dbx_lmdb: optimization

git-svn-id: http://svn.miranda-ng.org/main/trunk@16813 1316c22d-e87f-b044-9b9b-93d7a3e3ba9c

1 files changed, 10906 insertions, 10906 deletions

diff --git a/plugins/Dbx_mdb/src/lmdb/mdb.c b/plugins/Dbx_mdb/src/lmdb/mdb.c
index fe4976e3a2..a99e079c7f 100644
--- a/plugins/Dbx_mdb/src/lmdb/mdb.c
+++ b/plugins/Dbx_mdb/src/lmdb/mdb.c
@@ -1,10910 +1,10910 @@
-/** @file mdb.c
- *	@brief Lightning memory-mapped database library
- *
- *	A Btree-based database management library modeled loosely on the
- *	BerkeleyDB API, but much simplified.
- */
-/*
- * Copyright 2011-2016 Howard Chu, Symas Corp.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted only as authorized by the OpenLDAP
- * Public License.
- *
- * A copy of this license is available in the file LICENSE in the
- * top-level directory of the distribution or, alternatively, at
- * <http://www.OpenLDAP.org/license.html>.
- *
- * This code is derived from btree.c written by Martin Hedenfalk.
- *
- * Copyright (c) 2009, 2010 Martin Hedenfalk <martin@bzero.se>
- *
- * Permission to use, copy, modify, and distribute this software for any
- * purpose with or without fee is hereby granted, provided that the above
- * copyright notice and this permission notice appear in all copies.
- *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
- */
-#ifndef _GNU_SOURCE
-#define _GNU_SOURCE 1
-#endif
-
-#define MDB_VL32 1
-
+/** @file mdb.c

+ *	@brief Lightning memory-mapped database library

+ *

+ *	A Btree-based database management library modeled loosely on the

+ *	BerkeleyDB API, but much simplified.

+ */

+/*

+ * Copyright 2011-2016 Howard Chu, Symas Corp.

+ * All rights reserved.

+ *

+ * Redistribution and use in source and binary forms, with or without

+ * modification, are permitted only as authorized by the OpenLDAP

+ * Public License.

+ *

+ * A copy of this license is available in the file LICENSE in the

+ * top-level directory of the distribution or, alternatively, at

+ * <http://www.OpenLDAP.org/license.html>.

+ *

+ * This code is derived from btree.c written by Martin Hedenfalk.

+ *

+ * Copyright (c) 2009, 2010 Martin Hedenfalk <martin@bzero.se>

+ *

+ * Permission to use, copy, modify, and distribute this software for any

+ * purpose with or without fee is hereby granted, provided that the above

+ * copyright notice and this permission notice appear in all copies.

+ *

+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES

+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF

+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR

+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES

+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN

+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF

+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

+ */

+#ifndef _GNU_SOURCE

+#define _GNU_SOURCE 1

+#endif

+

+#define MDB_VL32 1

+

 #ifdef _WIN64

 #	pragma comment(lib, "lib/x64/ntdll.lib")

 #else

 #	pragma comment(lib, "lib/x86/ntdll.lib")

-#endif
-
-#pragma warning(disable: 4706)
-
-#if defined(MDB_VL32) || defined(__WIN64__)
-#define _FILE_OFFSET_BITS	64
-#endif
-#ifdef _WIN32
-#include <malloc.h>
-#include <windows.h>
-
-/* We use native NT APIs to setup the memory map, so that we can
- * let the DB file grow incrementally instead of always preallocating
- * the full size. These APIs are defined in <wdm.h> and <ntifs.h>
- * but those headers are meant for driver-level development and
- * conflict with the regular user-level headers, so we explicitly
- * declare them here. Using these APIs also means we must link to
- * ntdll.dll, which is not linked by default in user code.
- */
-
-NTSTATUS WINAPI
-	NtCreateSection(OUT PHANDLE sh, IN ACCESS_MASK acc,
-	IN void * oa OPTIONAL,
-	IN PLARGE_INTEGER ms OPTIONAL,
-	IN ULONG pp, IN ULONG aa, IN HANDLE fh OPTIONAL);
-
-typedef enum _SECTION_INHERIT {
-	ViewShare = 1,
-	ViewUnmap = 2
-} SECTION_INHERIT;
-
-NTSTATUS WINAPI
-	NtMapViewOfSection(IN PHANDLE sh, IN HANDLE ph,
-	IN OUT PVOID *addr, IN ULONG_PTR zbits,
-	IN SIZE_T cs, IN OUT PLARGE_INTEGER off OPTIONAL,
-	IN OUT PSIZE_T vs, IN SECTION_INHERIT ih,
-	IN ULONG at, IN ULONG pp);
-
-NTSTATUS WINAPI
-	NtClose(HANDLE h);
-
-/** getpid() returns int; MinGW defines pid_t but MinGW64 typedefs it
- *  as int64 which is wrong. MSVC doesn't define it at all, so just
- *  don't use it.
- */
-#define MDB_PID_T	int
-#define MDB_THR_T	DWORD
-#include <sys/types.h>
-#include <sys/stat.h>
-#ifdef __GNUC__
-# include <sys/param.h>
-#else
-# define LITTLE_ENDIAN	1234
-# define BIG_ENDIAN	4321
-# define BYTE_ORDER	LITTLE_ENDIAN
-# ifndef SSIZE_MAX
-#  define SSIZE_MAX	INT_MAX
-# endif
-#endif
-#else
-#include <sys/types.h>
-#include <sys/stat.h>
-#define MDB_PID_T	pid_t
-#define MDB_THR_T	pthread_t
-#include <sys/param.h>
-#include <sys/uio.h>
-#include <sys/mman.h>
-#ifdef HAVE_SYS_FILE_H
-#include <sys/file.h>
-#endif
-#include <fcntl.h>
-#endif
-
-#if defined(__mips) && defined(__linux)
-/* MIPS has cache coherency issues, requires explicit cache control */
-#include <asm/cachectl.h>
-extern int cacheflush(char *addr, int nbytes, int cache);
-#define CACHEFLUSH(addr, bytes, cache)	cacheflush(addr, bytes, cache)
-#else
-#define CACHEFLUSH(addr, bytes, cache)
-#endif
-
-#if defined(__linux) && !defined(MDB_FDATASYNC_WORKS)
-/** fdatasync is broken on ext3/ext4fs on older kernels, see
- *	description in #mdb_env_open2 comments. You can safely
- *	define MDB_FDATASYNC_WORKS if this code will only be run
- *	on kernels 3.6 and newer.
- */
-#define	BROKEN_FDATASYNC
-#endif
-
-#include <errno.h>
-#include <limits.h>
-#include <stddef.h>
-#include <inttypes.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <time.h>
-
-#ifdef _MSC_VER
-#include <io.h>
-typedef SSIZE_T	ssize_t;
-#else
-#include <unistd.h>
-#endif
-
-#if defined(__sun) || defined(ANDROID)
-/* Most platforms have posix_memalign, older may only have memalign */
-#define HAVE_MEMALIGN	1
-#include <malloc.h>
-#endif
-
-#if !(defined(BYTE_ORDER) || defined(__BYTE_ORDER))
-#include <netinet/in.h>
-#include <resolv.h>	/* defines BYTE_ORDER on HPUX and Solaris */
-#endif
-
-#if defined(__APPLE__) || defined (BSD)
-# if !(defined(MDB_USE_POSIX_MUTEX) || defined(MDB_USE_POSIX_SEM))
-# define MDB_USE_SYSV_SEM	1
-# endif
-# define MDB_FDATASYNC		fsync
-#elif defined(ANDROID)
-# define MDB_FDATASYNC		fsync
-#endif
-
-#ifndef _WIN32
-#include <pthread.h>
-#ifdef MDB_USE_POSIX_SEM
-# define MDB_USE_HASH		1
-#include <semaphore.h>
-#elif defined(MDB_USE_SYSV_SEM)
-#include <sys/ipc.h>
-#include <sys/sem.h>
-#ifdef _SEM_SEMUN_UNDEFINED
-union semun {
-	int val;
-	struct semid_ds *buf;
-	unsigned short *array;
-};
-#endif /* _SEM_SEMUN_UNDEFINED */
-#else
-#define MDB_USE_POSIX_MUTEX	1
-#endif /* MDB_USE_POSIX_SEM */
-#endif /* !_WIN32 */
-
-#if defined(_WIN32) + defined(MDB_USE_POSIX_SEM) + defined(MDB_USE_SYSV_SEM) \
-	+ defined(MDB_USE_POSIX_MUTEX) != 1
-# error "Ambiguous shared-lock implementation"
-#endif
-
-#ifdef USE_VALGRIND
-#include <valgrind/memcheck.h>
-#define VGMEMP_CREATE(h,r,z)    VALGRIND_CREATE_MEMPOOL(h,r,z)
-#define VGMEMP_ALLOC(h,a,s) VALGRIND_MEMPOOL_ALLOC(h,a,s)
-#define VGMEMP_FREE(h,a) VALGRIND_MEMPOOL_FREE(h,a)
-#define VGMEMP_DESTROY(h)	VALGRIND_DESTROY_MEMPOOL(h)
-#define VGMEMP_DEFINED(a,s)	VALGRIND_MAKE_MEM_DEFINED(a,s)
-#else
-#define VGMEMP_CREATE(h,r,z)
-#define VGMEMP_ALLOC(h,a,s)
-#define VGMEMP_FREE(h,a)
-#define VGMEMP_DESTROY(h)
-#define VGMEMP_DEFINED(a,s)
-#endif
-
-#ifndef BYTE_ORDER
-# if (defined(_LITTLE_ENDIAN) || defined(_BIG_ENDIAN)) && !(defined(_LITTLE_ENDIAN) && defined(_BIG_ENDIAN))
-/* Solaris just defines one or the other */
-#  define LITTLE_ENDIAN	1234
-#  define BIG_ENDIAN	4321
-#  ifdef _LITTLE_ENDIAN
-#   define BYTE_ORDER  LITTLE_ENDIAN
-#  else
-#   define BYTE_ORDER  BIG_ENDIAN
-#  endif
-# else
-#  define BYTE_ORDER   __BYTE_ORDER
-# endif
-#endif
-
-#ifndef LITTLE_ENDIAN
-#define LITTLE_ENDIAN	__LITTLE_ENDIAN
-#endif
-#ifndef BIG_ENDIAN
-#define BIG_ENDIAN	__BIG_ENDIAN
-#endif
-
-#if defined(__i386) || defined(__x86_64) || defined(_M_IX86)
-#define MISALIGNED_OK	1
-#endif
-
-#include "lmdb.h"
-#include "midl.h"
-
-#if (BYTE_ORDER == LITTLE_ENDIAN) == (BYTE_ORDER == BIG_ENDIAN)
-# error "Unknown or unsupported endianness (BYTE_ORDER)"
-#elif (-6 & 5) || CHAR_BIT != 8 || UINT_MAX < 0xffffffff || ULONG_MAX % 0xFFFF
-# error "Two's complement, reasonably sized integer types, please"
-#endif
-
-#ifdef __GNUC__
-/** Put infrequently used env functions in separate section */
-# ifdef __APPLE__
-#  define	ESECT	__attribute__ ((section("__TEXT,text_env")))
-# else
-#  define	ESECT	__attribute__ ((section("text_env")))
-# endif
-#else
-#define ESECT
-#endif
-
-#ifdef _WIN32
-#define CALL_CONV WINAPI
-#else
-#define CALL_CONV
-#endif
-
-/** @defgroup internal	LMDB Internals
- *	@{
- */
-/** @defgroup compat	Compatibility Macros
- *	A bunch of macros to minimize the amount of platform-specific ifdefs
- *	needed throughout the rest of the code. When the features this library
- *	needs are similar enough to POSIX to be hidden in a one-or-two line
- *	replacement, this macro approach is used.
- *	@{
- */
-
-	/** Features under development */
-#ifndef MDB_DEVEL
-#define MDB_DEVEL 0
-#endif
-
-	/** Wrapper around __func__, which is a C99 feature */
-#if __STDC_VERSION__ >= 199901L
-# define mdb_func_	__func__
-#elif __GNUC__ >= 2 || _MSC_VER >= 1300
-# define mdb_func_	__FUNCTION__
-#else
-/* If a debug message says <mdb_unknown>(), update the #if statements above */
-# define mdb_func_	"<mdb_unknown>"
-#endif
-
-/* Internal error codes, not exposed outside liblmdb */
-#define	MDB_NO_ROOT		(MDB_LAST_ERRCODE + 10)
-#ifdef _WIN32
-#define MDB_OWNERDEAD	((int) WAIT_ABANDONED)
-#elif defined MDB_USE_SYSV_SEM
-#define MDB_OWNERDEAD	(MDB_LAST_ERRCODE + 11)
-#elif defined(MDB_USE_POSIX_MUTEX) && defined(EOWNERDEAD)
-#define MDB_OWNERDEAD	EOWNERDEAD	/**< #LOCK_MUTEX0() result if dead owner */
-#endif
-
-#ifdef __GLIBC__
-#define	GLIBC_VER	((__GLIBC__ << 16 )| __GLIBC_MINOR__)
-#endif
-/** Some platforms define the EOWNERDEAD error code
- * even though they don't support Robust Mutexes.
- * Compile with -DMDB_USE_ROBUST=0, or use some other
- * mechanism like -DMDB_USE_SYSV_SEM instead of
- * -DMDB_USE_POSIX_MUTEX. (SysV semaphores are
- * also Robust, but some systems don't support them
- * either.)
- */
-#ifndef MDB_USE_ROBUST
-/* Android currently lacks Robust Mutex support. So does glibc < 2.4. */
-# if defined(MDB_USE_POSIX_MUTEX) && (defined(ANDROID) || \
-	(defined(__GLIBC__) && GLIBC_VER < 0x020004))
-#  define MDB_USE_ROBUST	0
-# else
-#  define MDB_USE_ROBUST	1
-/* glibc < 2.12 only provided _np API */
-#  if defined(__GLIBC__) && GLIBC_VER < 0x02000c
-#   define PTHREAD_MUTEX_ROBUST	PTHREAD_MUTEX_ROBUST_NP
-#   define pthread_mutexattr_setrobust(attr, flag)	pthread_mutexattr_setrobust_np(attr, flag)
-#   define pthread_mutex_consistent(mutex)	pthread_mutex_consistent_np(mutex)
-#  endif
-# endif
-#endif /* MDB_USE_ROBUST */
-
-#if defined(MDB_OWNERDEAD) && MDB_USE_ROBUST
-#define MDB_ROBUST_SUPPORTED	1
-#endif
-
-#ifdef _WIN32
-#define MDB_USE_HASH	1
-#define MDB_PIDLOCK	0
-#define THREAD_RET	DWORD
-#define pthread_t	HANDLE
-#define pthread_mutex_t	HANDLE
-#define pthread_cond_t	HANDLE
-typedef HANDLE mdb_mutex_t, mdb_mutexref_t;
-#define pthread_key_t	DWORD
-#define pthread_self()	GetCurrentThreadId()
-#define pthread_key_create(x,y)	\
-	((*(x) = TlsAlloc()) == TLS_OUT_OF_INDEXES ? ErrCode() : 0)
-#define pthread_key_delete(x)	TlsFree(x)
-#define pthread_getspecific(x)	TlsGetValue(x)
-#define pthread_setspecific(x,y)	(TlsSetValue(x,y) ? 0 : ErrCode())
-#define pthread_mutex_unlock(x)	ReleaseMutex(*x)
-#define pthread_mutex_lock(x)	WaitForSingleObject(*x, INFINITE)
-#define pthread_cond_signal(x)	SetEvent(*x)
-#define pthread_cond_wait(cond,mutex)	do{SignalObjectAndWait(*mutex, *cond, INFINITE, FALSE); WaitForSingleObject(*mutex, INFINITE);}while(0)
-#define THREAD_CREATE(thr,start,arg)	thr=CreateThread(NULL,0,start,arg,0,NULL)
-#define THREAD_FINISH(thr)	WaitForSingleObject(thr, INFINITE)
-#define LOCK_MUTEX0(mutex)		WaitForSingleObject(mutex, INFINITE)
-#define UNLOCK_MUTEX(mutex)		ReleaseMutex(mutex)
-#define mdb_mutex_consistent(mutex)	0
-#define getpid()	GetCurrentProcessId()
-#define	MDB_FDATASYNC(fd)	(!FlushFileBuffers(fd))
-#define	MDB_MSYNC(addr,len,flags)	(!FlushViewOfFile(addr,len))
-#define	ErrCode()	GetLastError()
-#define GET_PAGESIZE(x) {SYSTEM_INFO si; GetSystemInfo(&si); (x) = si.dwPageSize;}
-#define	close(fd)	(CloseHandle(fd) ? 0 : -1)
-#define	munmap(ptr,len)	UnmapViewOfFile(ptr)
-#ifdef PROCESS_QUERY_LIMITED_INFORMATION
-#define MDB_PROCESS_QUERY_LIMITED_INFORMATION PROCESS_QUERY_LIMITED_INFORMATION
-#else
-#define MDB_PROCESS_QUERY_LIMITED_INFORMATION 0x1000
-#endif
-#define	Z	"I"
-#else
-#define THREAD_RET	void *
-#define THREAD_CREATE(thr,start,arg)	pthread_create(&thr,NULL,start,arg)
-#define THREAD_FINISH(thr)	pthread_join(thr,NULL)
-#define	Z	"z"			/**< printf format modifier for size_t */
-
-	/** For MDB_LOCK_FORMAT: True if readers take a pid lock in the lockfile */
-#define MDB_PIDLOCK			1
-
-#ifdef MDB_USE_POSIX_SEM
-
-typedef sem_t *mdb_mutex_t, *mdb_mutexref_t;
-#define LOCK_MUTEX0(mutex)		mdb_sem_wait(mutex)
-#define UNLOCK_MUTEX(mutex)		sem_post(mutex)
-
-static int
-mdb_sem_wait(sem_t *sem)
-{
-   int rc;
-   while ((rc = sem_wait(sem)) && (rc = errno) == EINTR) ;
-   return rc;
-}
-
-#elif defined MDB_USE_SYSV_SEM
-
-typedef struct mdb_mutex {
-	int semid;
-	int semnum;
-	int *locked;
-} mdb_mutex_t[1], *mdb_mutexref_t;
-
-#define LOCK_MUTEX0(mutex)		mdb_sem_wait(mutex)
-#define UNLOCK_MUTEX(mutex)		do { \
-	struct sembuf sb = { 0, 1, SEM_UNDO }; \
-	sb.sem_num = (mutex)->semnum; \
-	*(mutex)->locked = 0; \
-	semop((mutex)->semid, &sb, 1); \
-} while(0)
-
-static int
-mdb_sem_wait(mdb_mutexref_t sem)
-{
-	int rc, *locked = sem->locked;
-	struct sembuf sb = { 0, -1, SEM_UNDO };
-	sb.sem_num = sem->semnum;
-	do {
-		if (!semop(sem->semid, &sb, 1)) {
-			rc = *locked ? MDB_OWNERDEAD : MDB_SUCCESS;
-			*locked = 1;
-			break;
-		}
-	} while ((rc = errno) == EINTR);
-	return rc;
-}
-
-#define mdb_mutex_consistent(mutex)	0
-
-#else	/* MDB_USE_POSIX_MUTEX: */
-	/** Shared mutex/semaphore as it is stored (mdb_mutex_t), and as
-	 *	local variables keep it (mdb_mutexref_t).
-	 *
-	 *	An mdb_mutex_t can be assigned to an mdb_mutexref_t.  They can
-	 *	be the same, or an array[size 1] and a pointer.
-	 *	@{
-	 */
-typedef pthread_mutex_t mdb_mutex_t[1], *mdb_mutexref_t;
-	/*	@} */
-	/** Lock the reader or writer mutex.
-	 *	Returns 0 or a code to give #mdb_mutex_failed(), as in #LOCK_MUTEX().
-	 */
-#define LOCK_MUTEX0(mutex)	pthread_mutex_lock(mutex)
-	/** Unlock the reader or writer mutex.
-	 */
-#define UNLOCK_MUTEX(mutex)	pthread_mutex_unlock(mutex)
-	/** Mark mutex-protected data as repaired, after death of previous owner.
-	 */
-#define mdb_mutex_consistent(mutex)	pthread_mutex_consistent(mutex)
-#endif	/* MDB_USE_POSIX_SEM || MDB_USE_SYSV_SEM */
-
-	/** Get the error code for the last failed system function.
-	 */
-#define	ErrCode()	errno
-
-	/** An abstraction for a file handle.
-	 *	On POSIX systems file handles are small integers. On Windows
-	 *	they're opaque pointers.
-	 */
-#define	HANDLE	int
-
-	/**	A value for an invalid file handle.
-	 *	Mainly used to initialize file variables and signify that they are
-	 *	unused.
-	 */
-#define INVALID_HANDLE_VALUE	(-1)
-
-	/** Get the size of a memory page for the system.
-	 *	This is the basic size that the platform's memory manager uses, and is
-	 *	fundamental to the use of memory-mapped files.
-	 */
-#define	GET_PAGESIZE(x)	((x) = sysconf(_SC_PAGE_SIZE))
-#endif
-
-#ifdef MDB_VL32
-#ifdef _WIN32
-#define	Y	"I64"
-#else
-#define	Y	"ll"
-#endif
-#else
-#define Y	Z
-#endif
-
-#if defined(_WIN32) || defined(MDB_USE_POSIX_SEM)
-#define MNAME_LEN	32
-#elif defined(MDB_USE_SYSV_SEM)
-#define MNAME_LEN	(sizeof(int))
-#else
-#define MNAME_LEN	(sizeof(pthread_mutex_t))
-#endif
-
-#ifdef MDB_USE_SYSV_SEM
-#define SYSV_SEM_FLAG	1		/**< SysV sems in lockfile format */
-#else
-#define SYSV_SEM_FLAG	0
-#endif
-
-/** @} */
-
-#ifdef MDB_ROBUST_SUPPORTED
-	/** Lock mutex, handle any error, set rc = result.
-	 *	Return 0 on success, nonzero (not rc) on error.
-	 */
-#define LOCK_MUTEX(rc, env, mutex) \
-	(((rc) = LOCK_MUTEX0(mutex)) && \
-	 ((rc) = mdb_mutex_failed(env, mutex, rc)))
-static int mdb_mutex_failed(MDB_env *env, mdb_mutexref_t mutex, int rc);
-#else
-#define LOCK_MUTEX(rc, env, mutex) ((rc) = LOCK_MUTEX0(mutex))
-#define mdb_mutex_failed(env, mutex, rc) (rc)
-#endif
-
-#ifndef _WIN32
-/**	A flag for opening a file and requesting synchronous data writes.
- *	This is only used when writing a meta page. It's not strictly needed;
- *	we could just do a normal write and then immediately perform a flush.
- *	But if this flag is available it saves us an extra system call.
- *
- *	@note If O_DSYNC is undefined but exists in /usr/include,
- * preferably set some compiler flag to get the definition.
- */
-#ifndef MDB_DSYNC
-# ifdef O_DSYNC
-# define MDB_DSYNC	O_DSYNC
-# else
-# define MDB_DSYNC	O_SYNC
-# endif
-#endif
-#endif
-
-/** Function for flushing the data of a file. Define this to fsync
- *	if fdatasync() is not supported.
- */
-#ifndef MDB_FDATASYNC
-# define MDB_FDATASYNC	fdatasync
-#endif
-
-#ifndef MDB_MSYNC
-# define MDB_MSYNC(addr,len,flags)	msync(addr,len,flags)
-#endif
-
-#ifndef MS_SYNC
-#define	MS_SYNC	1
-#endif
-
-#ifndef MS_ASYNC
-#define	MS_ASYNC	0
-#endif
-
-	/** A page number in the database.
-	 *	Note that 64 bit page numbers are overkill, since pages themselves
-	 *	already represent 12-13 bits of addressable memory, and the OS will
-	 *	always limit applications to a maximum of 63 bits of address space.
-	 *
-	 *	@note In the #MDB_node structure, we only store 48 bits of this value,
-	 *	which thus limits us to only 60 bits of addressable data.
-	 */
-typedef MDB_ID	pgno_t;
-
-	/** A transaction ID.
-	 *	See struct MDB_txn.mt_txnid for details.
-	 */
-typedef MDB_ID	txnid_t;
-
-/** @defgroup debug	Debug Macros
- *	@{
- */
-#ifndef MDB_DEBUG
-	/**	Enable debug output.  Needs variable argument macros (a C99 feature).
-	 *	Set this to 1 for copious tracing. Set to 2 to add dumps of all IDLs
-	 *	read from and written to the database (used for free space management).
-	 */
-#define MDB_DEBUG 0
-#endif
-
-#if MDB_DEBUG
-static int mdb_debug;
-static txnid_t mdb_debug_start;
-
-	/**	Print a debug message with printf formatting.
-	 *	Requires double parenthesis around 2 or more args.
-	 */
-# define DPRINTF(args) ((void) ((mdb_debug) && DPRINTF0 args))
-# define DPRINTF0(fmt, ...) \
-	fprintf(stderr, "%s:%d " fmt "\n", mdb_func_, __LINE__, __VA_ARGS__)
-#else
-# define DPRINTF(args)	((void) 0)
-#endif
-	/**	Print a debug string.
-	 *	The string is printed literally, with no format processing.
-	 */
-#define DPUTS(arg)	DPRINTF(("%s", arg))
-	/** Debuging output value of a cursor DBI: Negative in a sub-cursor. */
-#define DDBI(mc) \
-	(((mc)->mc_flags & C_SUB) ? -(int)(mc)->mc_dbi : (int)(mc)->mc_dbi)
-/** @} */
-
-	/**	@brief The maximum size of a database page.
-	 *
-	 *	It is 32k or 64k, since value-PAGEBASE must fit in
-	 *	#MDB_page.%mp_upper.
-	 *
-	 *	LMDB will use database pages < OS pages if needed.
-	 *	That causes more I/O in write transactions: The OS must
-	 *	know (read) the whole page before writing a partial page.
-	 *
-	 *	Note that we don't currently support Huge pages. On Linux,
-	 *	regular data files cannot use Huge pages, and in general
-	 *	Huge pages aren't actually pageable. We rely on the OS
-	 *	demand-pager to read our data and page it out when memory
-	 *	pressure from other processes is high. So until OSs have
-	 *	actual paging support for Huge pages, they're not viable.
-	 */
-#define MAX_PAGESIZE	 (PAGEBASE ? 0x10000 : 0x8000)
-
-	/** The minimum number of keys required in a database page.
-	 *	Setting this to a larger value will place a smaller bound on the
-	 *	maximum size of a data item. Data items larger than this size will
-	 *	be pushed into overflow pages instead of being stored directly in
-	 *	the B-tree node. This value used to default to 4. With a page size
-	 *	of 4096 bytes that meant that any item larger than 1024 bytes would
-	 *	go into an overflow page. That also meant that on average 2-3KB of
-	 *	each overflow page was wasted space. The value cannot be lower than
-	 *	2 because then there would no longer be a tree structure. With this
-	 *	value, items larger than 2KB will go into overflow pages, and on
-	 *	average only 1KB will be wasted.
-	 */
-#define MDB_MINKEYS	 2
-
-	/**	A stamp that identifies a file as an LMDB file.
-	 *	There's nothing special about this value other than that it is easily
-	 *	recognizable, and it will reflect any byte order mismatches.
-	 */
-#define MDB_MAGIC	 0xBEEFC0DE
-
-	/**	The version number for a database's datafile format. */
-#define MDB_DATA_VERSION	 ((MDB_DEVEL) ? 999 : 1)
-	/**	The version number for a database's lockfile format. */
-#define MDB_LOCK_VERSION	 ((MDB_DEVEL) ? 999 : 1)
-
-	/**	@brief The max size of a key we can write, or 0 for computed max.
-	 *
-	 *	This macro should normally be left alone or set to 0.
-	 *	Note that a database with big keys or dupsort data cannot be
-	 *	reliably modified by a liblmdb which uses a smaller max.
-	 *	The default is 511 for backwards compat, or 0 when #MDB_DEVEL.
-	 *
-	 *	Other values are allowed, for backwards compat.  However:
-	 *	A value bigger than the computed max can break if you do not
-	 *	know what you are doing, and liblmdb <= 0.9.10 can break when
-	 *	modifying a DB with keys/dupsort data bigger than its max.
-	 *
-	 *	Data items in an #MDB_DUPSORT database are also limited to
-	 *	this size, since they're actually keys of a sub-DB.  Keys and
-	 *	#MDB_DUPSORT data items must fit on a node in a regular page.
-	 */
-#ifndef MDB_MAXKEYSIZE
-#define MDB_MAXKEYSIZE	 ((MDB_DEVEL) ? 0 : 511)
-#endif
-
-	/**	The maximum size of a key we can write to the environment. */
-#if MDB_MAXKEYSIZE
-#define ENV_MAXKEY(env)	(MDB_MAXKEYSIZE)
-#else
-#define ENV_MAXKEY(env)	((env)->me_maxkey)
-#endif
-
-	/**	@brief The maximum size of a data item.
-	 *
-	 *	We only store a 32 bit value for node sizes.
-	 */
-#define MAXDATASIZE	0xffffffffUL
-
-#if MDB_DEBUG
-	/**	Key size which fits in a #DKBUF.
-	 *	@ingroup debug
-	 */
-#define DKBUF_MAXKEYSIZE ((MDB_MAXKEYSIZE) > 0 ? (MDB_MAXKEYSIZE) : 511)
-	/**	A key buffer.
-	 *	@ingroup debug
-	 *	This is used for printing a hex dump of a key's contents.
-	 */
-#define DKBUF	char kbuf[DKBUF_MAXKEYSIZE*2+1]
-	/**	Display a key in hex.
-	 *	@ingroup debug
-	 *	Invoke a function to display a key in hex.
-	 */
-#define	DKEY(x)	mdb_dkey(x, kbuf)
-#else
-#define	DKBUF
-#define DKEY(x)	0
-#endif
-
-	/** An invalid page number.
-	 *	Mainly used to denote an empty tree.
-	 */
-#define P_INVALID	 (~(pgno_t)0)
-
-	/** Test if the flags \b f are set in a flag word \b w. */
-#define F_ISSET(w, f)	 (((w) & (f)) == (f))
-
-	/** Round \b n up to an even number. */
-#define EVEN(n)		(((n) + 1U) & -2) /* sign-extending -2 to match n+1U */
-
-	/**	Used for offsets within a single page.
-	 *	Since memory pages are typically 4 or 8KB in size, 12-13 bits,
-	 *	this is plenty.
-	 */
-typedef uint16_t	 indx_t;
-
-	/**	Default size of memory map.
-	 *	This is certainly too small for any actual applications. Apps should always set
-	 *	the size explicitly using #mdb_env_set_mapsize().
-	 */
-#define DEFAULT_MAPSIZE	1048576
-
-/**	@defgroup readers	Reader Lock Table
- *	Readers don't acquire any locks for their data access. Instead, they
- *	simply record their transaction ID in the reader table. The reader
- *	mutex is needed just to find an empty slot in the reader table. The
- *	slot's address is saved in thread-specific data so that subsequent read
- *	transactions started by the same thread need no further locking to proceed.
- *
- *	If #MDB_NOTLS is set, the slot address is not saved in thread-specific data.
- *
- *	No reader table is used if the database is on a read-only filesystem, or
- *	if #MDB_NOLOCK is set.
- *
- *	Since the database uses multi-version concurrency control, readers don't
- *	actually need any locking. This table is used to keep track of which
- *	readers are using data from which old transactions, so that we'll know
- *	when a particular old transaction is no longer in use. Old transactions
- *	that have discarded any data pages can then have those pages reclaimed
- *	for use by a later write transaction.
- *
- *	The lock table is constructed such that reader slots are aligned with the
- *	processor's cache line size. Any slot is only ever used by one thread.
- *	This alignment guarantees that there will be no contention or cache
- *	thrashing as threads update their own slot info, and also eliminates
- *	any need for locking when accessing a slot.
- *
- *	A writer thread will scan every slot in the table to determine the oldest
- *	outstanding reader transaction. Any freed pages older than this will be
- *	reclaimed by the writer. The writer doesn't use any locks when scanning
- *	this table. This means that there's no guarantee that the writer will
- *	see the most up-to-date reader info, but that's not required for correct
- *	operation - all we need is to know the upper bound on the oldest reader,
- *	we don't care at all about the newest reader. So the only consequence of
- *	reading stale information here is that old pages might hang around a
- *	while longer before being reclaimed. That's actually good anyway, because
- *	the longer we delay reclaiming old pages, the more likely it is that a
- *	string of contiguous pages can be found after coalescing old pages from
- *	many old transactions together.
- *	@{
- */
-	/**	Number of slots in the reader table.
-	 *	This value was chosen somewhat arbitrarily. 126 readers plus a
-	 *	couple mutexes fit exactly into 8KB on my development machine.
-	 *	Applications should set the table size using #mdb_env_set_maxreaders().
-	 */
-#define DEFAULT_READERS	126
-
-	/**	The size of a CPU cache line in bytes. We want our lock structures
-	 *	aligned to this size to avoid false cache line sharing in the
-	 *	lock table.
-	 *	This value works for most CPUs. For Itanium this should be 128.
-	 */
-#ifndef CACHELINE
-#define CACHELINE	64
-#endif
-
-	/**	The information we store in a single slot of the reader table.
-	 *	In addition to a transaction ID, we also record the process and
-	 *	thread ID that owns a slot, so that we can detect stale information,
-	 *	e.g. threads or processes that went away without cleaning up.
-	 *	@note We currently don't check for stale records. We simply re-init
-	 *	the table when we know that we're the only process opening the
-	 *	lock file.
-	 */
-typedef struct MDB_rxbody {
-	/**	Current Transaction ID when this transaction began, or (txnid_t)-1.
-	 *	Multiple readers that start at the same time will probably have the
-	 *	same ID here. Again, it's not important to exclude them from
-	 *	anything; all we need to know is which version of the DB they
-	 *	started from so we can avoid overwriting any data used in that
-	 *	particular version.
-	 */
-	volatile txnid_t		mrb_txnid;
-	/** The process ID of the process owning this reader txn. */
-	volatile MDB_PID_T	mrb_pid;
-	/** The thread ID of the thread owning this txn. */
-	volatile MDB_THR_T	mrb_tid;
-} MDB_rxbody;
-
-	/** The actual reader record, with cacheline padding. */
-typedef struct MDB_reader {
-	union {
-		MDB_rxbody mrx;
-		/** shorthand for mrb_txnid */
-#define	mr_txnid	mru.mrx.mrb_txnid
-#define	mr_pid	mru.mrx.mrb_pid
-#define	mr_tid	mru.mrx.mrb_tid
-		/** cache line alignment */
-		char pad[(sizeof(MDB_rxbody)+CACHELINE-1) & ~(CACHELINE-1)];
-	} mru;
-} MDB_reader;
-
-	/** The header for the reader table.
-	 *	The table resides in a memory-mapped file. (This is a different file
-	 *	than is used for the main database.)
-	 *
-	 *	For POSIX the actual mutexes reside in the shared memory of this
-	 *	mapped file. On Windows, mutexes are named objects allocated by the
-	 *	kernel; we store the mutex names in this mapped file so that other
-	 *	processes can grab them. This same approach is also used on
-	 *	MacOSX/Darwin (using named semaphores) since MacOSX doesn't support
-	 *	process-shared POSIX mutexes. For these cases where a named object
-	 *	is used, the object name is derived from a 64 bit FNV hash of the
-	 *	environment pathname. As such, naming collisions are extremely
-	 *	unlikely. If a collision occurs, the results are unpredictable.
-	 */
-typedef struct MDB_txbody {
-		/** Stamp identifying this as an LMDB file. It must be set
-		 *	to #MDB_MAGIC. */
-	uint32_t	mtb_magic;
-		/** Format of this lock file. Must be set to #MDB_LOCK_FORMAT. */
-	uint32_t	mtb_format;
-#if defined(_WIN32) || defined(MDB_USE_POSIX_SEM)
-	char	mtb_rmname[MNAME_LEN];
-#elif defined(MDB_USE_SYSV_SEM)
-	int 	mtb_semid;
-	int		mtb_rlocked;
-#else
-		/** Mutex protecting access to this table.
-		 *	This is the reader table lock used with LOCK_MUTEX().
-		 */
-	mdb_mutex_t	mtb_rmutex;
-#endif
-		/**	The ID of the last transaction committed to the database.
-		 *	This is recorded here only for convenience; the value can always
-		 *	be determined by reading the main database meta pages.
-		 */
-	volatile txnid_t		mtb_txnid;
-		/** The number of slots that have been used in the reader table.
-		 *	This always records the maximum count, it is not decremented
-		 *	when readers release their slots.
-		 */
-	volatile unsigned	mtb_numreaders;
-} MDB_txbody;
-
-	/** The actual reader table definition. */
-typedef struct MDB_txninfo {
-	union {
-		MDB_txbody mtb;
-#define mti_magic	mt1.mtb.mtb_magic
-#define mti_format	mt1.mtb.mtb_format
-#define mti_rmutex	mt1.mtb.mtb_rmutex
-#define mti_rmname	mt1.mtb.mtb_rmname
-#define mti_txnid	mt1.mtb.mtb_txnid
-#define mti_numreaders	mt1.mtb.mtb_numreaders
-#ifdef MDB_USE_SYSV_SEM
-#define	mti_semid	mt1.mtb.mtb_semid
-#define	mti_rlocked	mt1.mtb.mtb_rlocked
-#endif
-		char pad[(sizeof(MDB_txbody)+CACHELINE-1) & ~(CACHELINE-1)];
-	} mt1;
-	union {
-#if defined(_WIN32) || defined(MDB_USE_POSIX_SEM)
-		char mt2_wmname[MNAME_LEN];
-#define	mti_wmname	mt2.mt2_wmname
-#elif defined MDB_USE_SYSV_SEM
-		int mt2_wlocked;
-#define mti_wlocked	mt2.mt2_wlocked
-#else
-		mdb_mutex_t	mt2_wmutex;
-#define mti_wmutex	mt2.mt2_wmutex
-#endif
-		char pad[(MNAME_LEN+CACHELINE-1) & ~(CACHELINE-1)];
-	} mt2;
-	MDB_reader	mti_readers[1];
-} MDB_txninfo;
-
-	/** Lockfile format signature: version, features and field layout */
-#define MDB_LOCK_FORMAT \
-	((uint32_t) \
-	 ((MDB_LOCK_VERSION) \
-	  /* Flags which describe functionality */ \
-	  + (SYSV_SEM_FLAG << 18) \
-	  + (((MDB_PIDLOCK) != 0) << 16)))
-/** @} */
-
-/** Common header for all page types.
- * Overflow records occupy a number of contiguous pages with no
- * headers on any page after the first.
- */
-typedef struct MDB_page {
-#define	mp_pgno	mp_p.p_pgno
-#define	mp_next	mp_p.p_next
-	union {
-		pgno_t		p_pgno;	/**< page number */
-		struct MDB_page *p_next; /**< for in-memory list of freed pages */
-	} mp_p;
-	uint16_t	mp_pad;
-/**	@defgroup mdb_page	Page Flags
- *	@ingroup internal
- *	Flags for the page headers.
- *	@{
- */
-#define	P_BRANCH	 0x01		/**< branch page */
-#define	P_LEAF		 0x02		/**< leaf page */
-#define	P_OVERFLOW	 0x04		/**< overflow page */
-#define	P_META		 0x08		/**< meta page */
-#define	P_DIRTY		 0x10		/**< dirty page, also set for #P_SUBP pages */
-#define	P_LEAF2		 0x20		/**< for #MDB_DUPFIXED records */
-#define	P_SUBP		 0x40		/**< for #MDB_DUPSORT sub-pages */
-#define	P_LOOSE		 0x4000		/**< page was dirtied then freed, can be reused */
-#define	P_KEEP		 0x8000		/**< leave this page alone during spill */
-/** @} */
-	uint16_t	mp_flags;		/**< @ref mdb_page */
-#define mp_lower	mp_pb.pb.pb_lower
-#define mp_upper	mp_pb.pb.pb_upper
-#define mp_pages	mp_pb.pb_pages
-	union {
-		struct {
-			indx_t		pb_lower;		/**< lower bound of free space */
-			indx_t		pb_upper;		/**< upper bound of free space */
-		} pb;
-		uint32_t	pb_pages;	/**< number of overflow pages */
-	} mp_pb;
-	indx_t		mp_ptrs[1];		/**< dynamic size */
-} MDB_page;
-
-	/** Size of the page header, excluding dynamic data at the end */
-#define PAGEHDRSZ	 ((unsigned) offsetof(MDB_page, mp_ptrs))
-
-	/** Address of first usable data byte in a page, after the header */
-#define METADATA(p)	 ((void *)((char *)(p) + PAGEHDRSZ))
-
-	/** ITS#7713, change PAGEBASE to handle 65536 byte pages */
-#define	PAGEBASE	((MDB_DEVEL) ? PAGEHDRSZ : 0)
-
-	/** Number of nodes on a page */
-#define NUMKEYS(p)	 (((p)->mp_lower - (PAGEHDRSZ-PAGEBASE)) >> 1)
-
-	/** The amount of space remaining in the page */
-#define SIZELEFT(p)	 (indx_t)((p)->mp_upper - (p)->mp_lower)
-
-	/** The percentage of space used in the page, in tenths of a percent. */
-#define PAGEFILL(env, p) (1000L * ((env)->me_psize - PAGEHDRSZ - SIZELEFT(p)) / \
-				((env)->me_psize - PAGEHDRSZ))
-	/** The minimum page fill factor, in tenths of a percent.
-	 *	Pages emptier than this are candidates for merging.
-	 */
-#define FILL_THRESHOLD	 250
-
-	/** Test if a page is a leaf page */
-#define IS_LEAF(p)	 F_ISSET((p)->mp_flags, P_LEAF)
-	/** Test if a page is a LEAF2 page */
-#define IS_LEAF2(p)	 F_ISSET((p)->mp_flags, P_LEAF2)
-	/** Test if a page is a branch page */
-#define IS_BRANCH(p)	 F_ISSET((p)->mp_flags, P_BRANCH)
-	/** Test if a page is an overflow page */
-#define IS_OVERFLOW(p)	 F_ISSET((p)->mp_flags, P_OVERFLOW)
-	/** Test if a page is a sub page */
-#define IS_SUBP(p)	 F_ISSET((p)->mp_flags, P_SUBP)
-
-	/** The number of overflow pages needed to store the given size. */
-#define OVPAGES(size, psize)	((PAGEHDRSZ-1 + (size)) / (psize) + 1)
-
-	/** Link in #MDB_txn.%mt_loose_pgs list */
-#define NEXT_LOOSE_PAGE(p)		(*(MDB_page **)((p) + 2))
-
-	/** Header for a single key/data pair within a page.
-	 * Used in pages of type #P_BRANCH and #P_LEAF without #P_LEAF2.
-	 * We guarantee 2-byte alignment for 'MDB_node's.
-	 */
-typedef struct MDB_node {
-	/** lo and hi are used for data size on leaf nodes and for
-	 * child pgno on branch nodes. On 64 bit platforms, flags
-	 * is also used for pgno. (Branch nodes have no flags).
-	 * They are in host byte order in case that lets some
-	 * accesses be optimized into a 32-bit word access.
-	 */
-#if BYTE_ORDER == LITTLE_ENDIAN
-	unsigned short	mn_lo, mn_hi;	/**< part of data size or pgno */
-#else
-	unsigned short	mn_hi, mn_lo;
-#endif
-/** @defgroup mdb_node Node Flags
- *	@ingroup internal
- *	Flags for node headers.
- *	@{
- */
-#define F_BIGDATA	 0x01			/**< data put on overflow page */
-#define F_SUBDATA	 0x02			/**< data is a sub-database */
-#define F_DUPDATA	 0x04			/**< data has duplicates */
-
-/** valid flags for #mdb_node_add() */
-#define	NODE_ADD_FLAGS	(F_DUPDATA|F_SUBDATA|MDB_RESERVE|MDB_APPEND)
-
-/** @} */
-	unsigned short	mn_flags;		/**< @ref mdb_node */
-	unsigned short	mn_ksize;		/**< key size */
-	char		mn_data[1];			/**< key and data are appended here */
-} MDB_node;
-
-	/** Size of the node header, excluding dynamic data at the end */
-#define NODESIZE	 offsetof(MDB_node, mn_data)
-
-	/** Bit position of top word in page number, for shifting mn_flags */
-#define PGNO_TOPWORD ((pgno_t)-1 > 0xffffffffu ? 32 : 0)
-
-	/** Size of a node in a branch page with a given key.
-	 *	This is just the node header plus the key, there is no data.
-	 */
-#define INDXSIZE(k)	 (NODESIZE + ((k) == NULL ? 0 : (k)->mv_size))
-
-	/** Size of a node in a leaf page with a given key and data.
-	 *	This is node header plus key plus data size.
-	 */
-#define LEAFSIZE(k, d)	 (NODESIZE + (k)->mv_size + (d)->mv_size)
-
-	/** Address of node \b i in page \b p */
-#define NODEPTR(p, i)	 ((MDB_node *)((char *)(p) + (p)->mp_ptrs[i] + PAGEBASE))
-
-	/** Address of the key for the node */
-#define NODEKEY(node)	 (void *)((node)->mn_data)
-
-	/** Address of the data for a node */
-#define NODEDATA(node)	 (void *)((char *)(node)->mn_data + (node)->mn_ksize)
-
-	/** Get the page number pointed to by a branch node */
-#define NODEPGNO(node) \
-	((node)->mn_lo | ((pgno_t) (node)->mn_hi << 16) | \
-	 (PGNO_TOPWORD ? ((pgno_t) (node)->mn_flags << PGNO_TOPWORD) : 0))
-	/** Set the page number in a branch node */
-#define SETPGNO(node,pgno)	do { \
-	(node)->mn_lo = (pgno) & 0xffff; (node)->mn_hi = (pgno) >> 16; \
-	if (PGNO_TOPWORD) (node)->mn_flags = (pgno) >> PGNO_TOPWORD; } while(0)
-
-	/** Get the size of the data in a leaf node */
-#define NODEDSZ(node)	 ((node)->mn_lo | ((unsigned)(node)->mn_hi << 16))
-	/** Set the size of the data for a leaf node */
-#define SETDSZ(node,size)	do { \
-	(node)->mn_lo = (size) & 0xffff; (node)->mn_hi = (size) >> 16;} while(0)
-	/** The size of a key in a node */
-#define NODEKSZ(node)	 ((node)->mn_ksize)
-
-	/** Copy a page number from src to dst */
-#ifdef MISALIGNED_OK
-#define COPY_PGNO(dst,src)	dst = src
-#else
-#if SIZE_MAX > 4294967295UL
-#define COPY_PGNO(dst,src)	do { \
-	unsigned short *s, *d;	\
-	s = (unsigned short *)&(src);	\
-	d = (unsigned short *)&(dst);	\
-	*d++ = *s++;	\
-	*d++ = *s++;	\
-	*d++ = *s++;	\
-	*d = *s;	\
-} while (0)
-#else
-#define COPY_PGNO(dst,src)	do { \
-	unsigned short *s, *d;	\
-	s = (unsigned short *)&(src);	\
-	d = (unsigned short *)&(dst);	\
-	*d++ = *s++;	\
-	*d = *s;	\
-} while (0)
-#endif
-#endif
-	/** The address of a key in a LEAF2 page.
-	 *	LEAF2 pages are used for #MDB_DUPFIXED sorted-duplicate sub-DBs.
-	 *	There are no node headers, keys are stored contiguously.
-	 */
-#define LEAF2KEY(p, i, ks)	((char *)(p) + PAGEHDRSZ + ((i)*(ks)))
-
-	/** Set the \b node's key into \b keyptr, if requested. */
-#define MDB_GET_KEY(node, keyptr)	{ if ((keyptr) != NULL) { \
-	(keyptr)->mv_size = NODEKSZ(node); (keyptr)->mv_data = NODEKEY(node); } }
-
-	/** Set the \b node's key into \b key. */
-#define MDB_GET_KEY2(node, key)	{ key.mv_size = NODEKSZ(node); key.mv_data = NODEKEY(node); }
-
-	/** Information about a single database in the environment. */
-typedef struct MDB_db {
-	uint32_t	md_pad;		/**< also ksize for LEAF2 pages */
-	uint16_t	md_flags;	/**< @ref mdb_dbi_open */
-	uint16_t	md_depth;	/**< depth of this tree */
-	pgno_t		md_branch_pages;	/**< number of internal pages */
-	pgno_t		md_leaf_pages;		/**< number of leaf pages */
-	pgno_t		md_overflow_pages;	/**< number of overflow pages */
-	mdb_size_t	md_entries;		/**< number of data items */
-	pgno_t		md_root;		/**< the root page of this tree */
-} MDB_db;
-
-	/** mdb_dbi_open flags */
-#define MDB_VALID	0x8000		/**< DB handle is valid, for me_dbflags */
-#define PERSISTENT_FLAGS	(0xffff & ~(MDB_VALID))
-#define VALID_FLAGS	(MDB_REVERSEKEY|MDB_DUPSORT|MDB_INTEGERKEY|MDB_DUPFIXED|\
-	MDB_INTEGERDUP|MDB_REVERSEDUP|MDB_CREATE)
-
-	/** Handle for the DB used to track free pages. */
-#define	FREE_DBI	0
-	/** Handle for the default DB. */
-#define	MAIN_DBI	1
-	/** Number of DBs in metapage (free and main) - also hardcoded elsewhere */
-#define CORE_DBS	2
-
-	/** Number of meta pages - also hardcoded elsewhere */
-#define NUM_METAS	2
-
-	/** Meta page content.
-	 *	A meta page is the start point for accessing a database snapshot.
-	 *	Pages 0-1 are meta pages. Transaction N writes meta page #(N % 2).
-	 */
-typedef struct MDB_meta {
-		/** Stamp identifying this as an LMDB file. It must be set
-		 *	to #MDB_MAGIC. */
-	uint32_t	mm_magic;
-		/** Version number of this file. Must be set to #MDB_DATA_VERSION. */
-	uint32_t	mm_version;
-#ifdef MDB_VL32
-	union {		/* always zero since we don't support fixed mapping in MDB_VL32 */
-		MDB_ID	mmun_ull;
-		void *mmun_address;
-	} mm_un;
-#define	mm_address mm_un.mmun_address
-#else
-	void		*mm_address;		/**< address for fixed mapping */
-#endif
-	pgno_t		mm_mapsize;			/**< size of mmap region */
-	MDB_db		mm_dbs[CORE_DBS];	/**< first is free space, 2nd is main db */
-	/** The size of pages used in this DB */
-#define	mm_psize	mm_dbs[FREE_DBI].md_pad
-	/** Any persistent environment flags. @ref mdb_env */
-#define	mm_flags	mm_dbs[FREE_DBI].md_flags
-	pgno_t		mm_last_pg;			/**< last used page in file */
-	volatile txnid_t	mm_txnid;	/**< txnid that committed this page */
-} MDB_meta;
-
-	/** Buffer for a stack-allocated meta page.
-	 *	The members define size and alignment, and silence type
-	 *	aliasing warnings.  They are not used directly; that could
-	 *	mean incorrectly using several union members in parallel.
-	 */
-typedef union MDB_metabuf {
-	MDB_page	mb_page;
-	struct {
-		char		mm_pad[PAGEHDRSZ];
-		MDB_meta	mm_meta;
-	} mb_metabuf;
-} MDB_metabuf;
-
-	/** Auxiliary DB info.
-	 *	The information here is mostly static/read-only. There is
-	 *	only a single copy of this record in the environment.
-	 */
-typedef struct MDB_dbx {
-	MDB_val		md_name;		/**< name of the database */
-	MDB_cmp_func	*md_cmp;	/**< function for comparing keys */
-	MDB_cmp_func	*md_dcmp;	/**< function for comparing data items */
-	MDB_rel_func	*md_rel;	/**< user relocate function */
-	void		*md_relctx;		/**< user-provided context for md_rel */
-} MDB_dbx;
-
-	/** A database transaction.
-	 *	Every operation requires a transaction handle.
-	 */
-struct MDB_txn {
-	MDB_txn		*mt_parent;		/**< parent of a nested txn */
-	/** Nested txn under this txn, set together with flag #MDB_TXN_HAS_CHILD */
-	MDB_txn		*mt_child;
-	pgno_t		mt_next_pgno;	/**< next unallocated page */
-#ifdef MDB_VL32
-	pgno_t		mt_last_pgno;	/**< last written page */
-#endif
-	/** The ID of this transaction. IDs are integers incrementing from 1.
-	 *	Only committed write transactions increment the ID. If a transaction
-	 *	aborts, the ID may be re-used by the next writer.
-	 */
-	txnid_t		mt_txnid;
-	MDB_env		*mt_env;		/**< the DB environment */
-	/** The list of pages that became unused during this transaction.
-	 */
-	MDB_IDL		mt_free_pgs;
-	/** The list of loose pages that became unused and may be reused
-	 *	in this transaction, linked through #NEXT_LOOSE_PAGE(page).
-	 */
-	MDB_page	*mt_loose_pgs;
-	/* #Number of loose pages (#mt_loose_pgs) */
-	int			mt_loose_count;
-	/** The sorted list of dirty pages we temporarily wrote to disk
-	 *	because the dirty list was full. page numbers in here are
-	 *	shifted left by 1, deleted slots have the LSB set.
-	 */
-	MDB_IDL		mt_spill_pgs;
-	union {
-		/** For write txns: Modified pages. Sorted when not MDB_WRITEMAP. */
-		MDB_ID2L	dirty_list;
-		/** For read txns: This thread/txn's reader table slot, or NULL. */
-		MDB_reader	*reader;
-	} mt_u;
-	/** Array of records for each DB known in the environment. */
-	MDB_dbx		*mt_dbxs;
-	/** Array of MDB_db records for each known DB */
-	MDB_db		*mt_dbs;
-	/** Array of sequence numbers for each DB handle */
-	unsigned int	*mt_dbiseqs;
-/** @defgroup mt_dbflag	Transaction DB Flags
- *	@ingroup internal
- * @{
- */
-#define DB_DIRTY	0x01		/**< DB was modified or is DUPSORT data */
-#define DB_STALE	0x02		/**< Named-DB record is older than txnID */
-#define DB_NEW		0x04		/**< Named-DB handle opened in this txn */
-#define DB_VALID	0x08		/**< DB handle is valid, see also #MDB_VALID */
-#define DB_USRVALID	0x10		/**< As #DB_VALID, but not set for #FREE_DBI */
-/** @} */
-	/** In write txns, array of cursors for each DB */
-	MDB_cursor	**mt_cursors;
-	/** Array of flags for each DB */
-	unsigned char	*mt_dbflags;
-#ifdef MDB_VL32
-	/** List of read-only pages (actually chunks) */
-	MDB_ID3L	mt_rpages;
-	/** We map chunks of 16 pages. Even though Windows uses 4KB pages, all
-	 * mappings must begin on 64KB boundaries. So we round off all pgnos to
-	 * a chunk boundary. We do the same on Linux for symmetry, and also to
-	 * reduce the frequency of mmap/munmap calls.
-	 */
-#define MDB_RPAGE_CHUNK	16
-#define MDB_TRPAGE_SIZE	4096	/**< size of #mt_rpages array of chunks */
-#define MDB_TRPAGE_MAX	(MDB_TRPAGE_SIZE-1)	/**< maximum chunk index */
-	unsigned int mt_rpcheck;	/**< threshold for reclaiming unref'd chunks */
-#endif
-	/**	Number of DB records in use, or 0 when the txn is finished.
-	 *	This number only ever increments until the txn finishes; we
-	 *	don't decrement it when individual DB handles are closed.
-	 */
-	MDB_dbi		mt_numdbs;
-
-/** @defgroup mdb_txn	Transaction Flags
- *	@ingroup internal
- *	@{
- */
-	/** #mdb_txn_begin() flags */
-#define MDB_TXN_BEGIN_FLAGS	(MDB_NOMETASYNC|MDB_NOSYNC|MDB_RDONLY)
-#define MDB_TXN_NOMETASYNC	MDB_NOMETASYNC	/**< don't sync meta for this txn on commit */
-#define MDB_TXN_NOSYNC		MDB_NOSYNC	/**< don't sync this txn on commit */
-#define MDB_TXN_RDONLY		MDB_RDONLY	/**< read-only transaction */
-	/* internal txn flags */
-#define MDB_TXN_WRITEMAP	MDB_WRITEMAP	/**< copy of #MDB_env flag in writers */
-#define MDB_TXN_FINISHED	0x01		/**< txn is finished or never began */
-#define MDB_TXN_ERROR		0x02		/**< txn is unusable after an error */
-#define MDB_TXN_DIRTY		0x04		/**< must write, even if dirty list is empty */
-#define MDB_TXN_SPILLS		0x08		/**< txn or a parent has spilled pages */
-#define MDB_TXN_HAS_CHILD	0x10		/**< txn has an #MDB_txn.%mt_child */
-	/** most operations on the txn are currently illegal */
-#define MDB_TXN_BLOCKED		(MDB_TXN_FINISHED|MDB_TXN_ERROR|MDB_TXN_HAS_CHILD)
-/** @} */
-	unsigned int	mt_flags;		/**< @ref mdb_txn */
-	/** #dirty_list room: Array size - \#dirty pages visible to this txn.
-	 *	Includes ancestor txns' dirty pages not hidden by other txns'
-	 *	dirty/spilled pages. Thus commit(nested txn) has room to merge
-	 *	dirty_list into mt_parent after freeing hidden mt_parent pages.
-	 */
-	unsigned int	mt_dirty_room;
-};
-
-/** Enough space for 2^32 nodes with minimum of 2 keys per node. I.e., plenty.
- * At 4 keys per node, enough for 2^64 nodes, so there's probably no need to
- * raise this on a 64 bit machine.
- */
-#define CURSOR_STACK		 32
-
-struct MDB_xcursor;
-
-	/** Cursors are used for all DB operations.
-	 *	A cursor holds a path of (page pointer, key index) from the DB
-	 *	root to a position in the DB, plus other state. #MDB_DUPSORT
-	 *	cursors include an xcursor to the current data item. Write txns
-	 *	track their cursors and keep them up to date when data moves.
-	 *	Exception: An xcursor's pointer to a #P_SUBP page can be stale.
-	 *	(A node with #F_DUPDATA but no #F_SUBDATA contains a subpage).
-	 */
-struct MDB_cursor {
-	/** Next cursor on this DB in this txn */
-	MDB_cursor	*mc_next;
-	/** Backup of the original cursor if this cursor is a shadow */
-	MDB_cursor	*mc_backup;
-	/** Context used for databases with #MDB_DUPSORT, otherwise NULL */
-	struct MDB_xcursor	*mc_xcursor;
-	/** The transaction that owns this cursor */
-	MDB_txn		*mc_txn;
-	/** The database handle this cursor operates on */
-	MDB_dbi		mc_dbi;
-	/** The database record for this cursor */
-	MDB_db		*mc_db;
-	/** The database auxiliary record for this cursor */
-	MDB_dbx		*mc_dbx;
-	/** The @ref mt_dbflag for this database */
-	unsigned char	*mc_dbflag;
-	unsigned short 	mc_snum;	/**< number of pushed pages */
-	unsigned short	mc_top;		/**< index of top page, normally mc_snum-1 */
-/** @defgroup mdb_cursor	Cursor Flags
- *	@ingroup internal
- *	Cursor state flags.
- *	@{
- */
-#define C_INITIALIZED	0x01	/**< cursor has been initialized and is valid */
-#define C_EOF	0x02			/**< No more data */
-#define C_SUB	0x04			/**< Cursor is a sub-cursor */
-#define C_DEL	0x08			/**< last op was a cursor_del */
-#define C_UNTRACK	0x40		/**< Un-track cursor when closing */
-#define C_WRITEMAP	MDB_TXN_WRITEMAP /**< Copy of txn flag */
-/** Read-only cursor into the txn's original snapshot in the map.
- *	Set for read-only txns, and in #mdb_page_alloc() for #FREE_DBI when
- *	#MDB_DEVEL & 2. Only implements code which is necessary for this.
- */
-#define C_ORIG_RDONLY	MDB_TXN_RDONLY
-/** @} */
-	unsigned int	mc_flags;	/**< @ref mdb_cursor */
-	MDB_page	*mc_pg[CURSOR_STACK];	/**< stack of pushed pages */
-	indx_t		mc_ki[CURSOR_STACK];	/**< stack of page indices */
-#ifdef MDB_VL32
-	MDB_page	*mc_ovpg;		/**< a referenced overflow page */
-#endif
-};
-
-	/** Context for sorted-dup records.
-	 *	We could have gone to a fully recursive design, with arbitrarily
-	 *	deep nesting of sub-databases. But for now we only handle these
-	 *	levels - main DB, optional sub-DB, sorted-duplicate DB.
-	 */
-typedef struct MDB_xcursor {
-	/** A sub-cursor for traversing the Dup DB */
-	MDB_cursor mx_cursor;
-	/** The database record for this Dup DB */
-	MDB_db	mx_db;
-	/**	The auxiliary DB record for this Dup DB */
-	MDB_dbx	mx_dbx;
-	/** The @ref mt_dbflag for this Dup DB */
-	unsigned char mx_dbflag;
-} MDB_xcursor;
-
-	/** State of FreeDB old pages, stored in the MDB_env */
-typedef struct MDB_pgstate {
-	pgno_t		*mf_pghead;	/**< Reclaimed freeDB pages, or NULL before use */
-	txnid_t		mf_pglast;	/**< ID of last used record, or 0 if !mf_pghead */
-} MDB_pgstate;
-
-	/** The database environment. */
-struct MDB_env {
-	HANDLE		me_fd;		/**< The main data file */
-	HANDLE		me_lfd;		/**< The lock file */
-	HANDLE		me_mfd;			/**< just for writing the meta pages */
-#if defined(MDB_VL32) && defined(_WIN32)
-	HANDLE		me_fmh;		/**< File Mapping handle */
-#endif
-	/** Failed to update the meta page. Probably an I/O error. */
-#define	MDB_FATAL_ERROR	0x80000000U
-	/** Some fields are initialized. */
-#define	MDB_ENV_ACTIVE	0x20000000U
-	/** me_txkey is set */
-#define	MDB_ENV_TXKEY	0x10000000U
-	/** fdatasync is unreliable */
-#define	MDB_FSYNCONLY	0x08000000U
-	uint32_t 	me_flags;		/**< @ref mdb_env */
-	unsigned int	me_psize;	/**< DB page size, inited from me_os_psize */
-	unsigned int	me_os_psize;	/**< OS page size, from #GET_PAGESIZE */
-	unsigned int	me_maxreaders;	/**< size of the reader table */
-	/** Max #MDB_txninfo.%mti_numreaders of interest to #mdb_env_close() */
-	volatile int	me_close_readers;
-	MDB_dbi		me_numdbs;		/**< number of DBs opened */
-	MDB_dbi		me_maxdbs;		/**< size of the DB table */
-	MDB_PID_T	me_pid;		/**< process ID of this env */
-	char		*me_path;		/**< path to the DB files */
-	char		*me_map;		/**< the memory map of the data file */
-	MDB_txninfo	*me_txns;		/**< the memory map of the lock file or NULL */
-	MDB_meta	*me_metas[NUM_METAS];	/**< pointers to the two meta pages */
-	void		*me_pbuf;		/**< scratch area for DUPSORT put() */
-	MDB_txn		*me_txn;		/**< current write transaction */
-	MDB_txn		*me_txn0;		/**< prealloc'd write transaction */
-	mdb_size_t	me_mapsize;		/**< size of the data memory map */
-	off_t		me_size;		/**< current file size */
-	pgno_t		me_maxpg;		/**< me_mapsize / me_psize */
-	MDB_dbx		*me_dbxs;		/**< array of static DB info */
-	uint16_t	*me_dbflags;	/**< array of flags from MDB_db.md_flags */
-	unsigned int	*me_dbiseqs;	/**< array of dbi sequence numbers */
-	pthread_key_t	me_txkey;	/**< thread-key for readers */
-	txnid_t		me_pgoldest;	/**< ID of oldest reader last time we looked */
-	MDB_pgstate	me_pgstate;		/**< state of old pages from freeDB */
-#	define		me_pglast	me_pgstate.mf_pglast
-#	define		me_pghead	me_pgstate.mf_pghead
-	MDB_page	*me_dpages;		/**< list of malloc'd blocks for re-use */
-	/** IDL of pages that became unused in a write txn */
-	MDB_IDL		me_free_pgs;
-	/** ID2L of pages written during a write txn. Length MDB_IDL_UM_SIZE. */
-	MDB_ID2L	me_dirty_list;
-	/** Max number of freelist items that can fit in a single overflow page */
-	int			me_maxfree_1pg;
-	/** Max size of a node on a page */
-	unsigned int	me_nodemax;
-#if !(MDB_MAXKEYSIZE)
-	unsigned int	me_maxkey;	/**< max size of a key */
-#endif
-	int		me_live_reader;		/**< have liveness lock in reader table */
-#ifdef _WIN32
-	int		me_pidquery;		/**< Used in OpenProcess */
-#endif
-#ifdef MDB_USE_POSIX_MUTEX	/* Posix mutexes reside in shared mem */
-#	define		me_rmutex	me_txns->mti_rmutex /**< Shared reader lock */
-#	define		me_wmutex	me_txns->mti_wmutex /**< Shared writer lock */
-#else
-	mdb_mutex_t	me_rmutex;
-	mdb_mutex_t	me_wmutex;
-#endif
-#ifdef MDB_VL32
-	MDB_ID3L	me_rpages;	/**< like #mt_rpages, but global to env */
-	pthread_mutex_t	me_rpmutex;	/**< control access to #me_rpages */
-#define MDB_ERPAGE_SIZE	16384
-#define MDB_ERPAGE_MAX	(MDB_ERPAGE_SIZE-1)
-	unsigned int me_rpcheck;
-#endif
-	void		*me_userctx;	 /**< User-settable context */
-	MDB_assert_func *me_assert_func; /**< Callback for assertion failures */
-};
-
-	/** Nested transaction */
-typedef struct MDB_ntxn {
-	MDB_txn		mnt_txn;		/**< the transaction */
-	MDB_pgstate	mnt_pgstate;	/**< parent transaction's saved freestate */
-} MDB_ntxn;
-
-	/** max number of pages to commit in one writev() call */
-#define MDB_COMMIT_PAGES	 64
-#if defined(IOV_MAX) && IOV_MAX < MDB_COMMIT_PAGES
-#undef MDB_COMMIT_PAGES
-#define MDB_COMMIT_PAGES	IOV_MAX
-#endif
-
-	/** max bytes to write in one call */
-#define MAX_WRITE		(0x40000000U >> (sizeof(ssize_t) == 4))
-
-	/** Check \b txn and \b dbi arguments to a function */
-#define TXN_DBI_EXIST(txn, dbi, validity) \
-	((txn) && (dbi)<(txn)->mt_numdbs && ((txn)->mt_dbflags[dbi] & (validity)))
-
-	/** Check for misused \b dbi handles */
-#define TXN_DBI_CHANGED(txn, dbi) \
-	((txn)->mt_dbiseqs[dbi] != (txn)->mt_env->me_dbiseqs[dbi])
-
-static int  mdb_page_alloc(MDB_cursor *mc, int num, MDB_page **mp);
-static int  mdb_page_new(MDB_cursor *mc, uint32_t flags, int num, MDB_page **mp);
-static int  mdb_page_touch(MDB_cursor *mc);
-
-#define MDB_END_NAMES {"committed", "empty-commit", "abort", "reset", \
-	"reset-tmp", "fail-begin", "fail-beginchild"}
-enum {
-	/* mdb_txn_end operation number, for logging */
-	MDB_END_COMMITTED, MDB_END_EMPTY_COMMIT, MDB_END_ABORT, MDB_END_RESET,
-	MDB_END_RESET_TMP, MDB_END_FAIL_BEGIN, MDB_END_FAIL_BEGINCHILD
-};
-#define MDB_END_OPMASK	0x0F	/**< mask for #mdb_txn_end() operation number */
-#define MDB_END_UPDATE	0x10	/**< update env state (DBIs) */
-#define MDB_END_FREE	0x20	/**< free txn unless it is #MDB_env.%me_txn0 */
-#define MDB_END_SLOT MDB_NOTLS	/**< release any reader slot if #MDB_NOTLS */
-static void mdb_txn_end(MDB_txn *txn, unsigned mode);
-
-static int  mdb_page_get(MDB_cursor *mc, pgno_t pgno, MDB_page **mp, int *lvl);
-static int  mdb_page_search_root(MDB_cursor *mc,
-			    MDB_val *key, int modify);
-#define MDB_PS_MODIFY	1
-#define MDB_PS_ROOTONLY	2
-#define MDB_PS_FIRST	4
-#define MDB_PS_LAST		8
-static int  mdb_page_search(MDB_cursor *mc,
-			    MDB_val *key, int flags);
-static int	mdb_page_merge(MDB_cursor *csrc, MDB_cursor *cdst);
-
-#define MDB_SPLIT_REPLACE	MDB_APPENDDUP	/**< newkey is not new */
-static int	mdb_page_split(MDB_cursor *mc, MDB_val *newkey, MDB_val *newdata,
-				pgno_t newpgno, unsigned int nflags);
-
-static int  mdb_env_read_header(MDB_env *env, MDB_meta *meta);
-static MDB_meta *mdb_env_pick_meta(const MDB_env *env);
-static int  mdb_env_write_meta(MDB_txn *txn);
-#ifdef MDB_USE_POSIX_MUTEX /* Drop unused excl arg */
-# define mdb_env_close0(env, excl) mdb_env_close1(env)
-#endif
-static void mdb_env_close0(MDB_env *env, int excl);
-
-static MDB_node *mdb_node_search(MDB_cursor *mc, MDB_val *key, int *exactp);
-static int  mdb_node_add(MDB_cursor *mc, indx_t indx,
-			    MDB_val *key, MDB_val *data, pgno_t pgno, unsigned int flags);
-static void mdb_node_del(MDB_cursor *mc, int ksize);
-static void mdb_node_shrink(MDB_page *mp, indx_t indx);
-static int	mdb_node_move(MDB_cursor *csrc, MDB_cursor *cdst, int fromleft);
-static int  mdb_node_read(MDB_cursor *mc, MDB_node *leaf, MDB_val *data);
-static size_t	mdb_leaf_size(MDB_env *env, MDB_val *key, MDB_val *data);
-static size_t	mdb_branch_size(MDB_env *env, MDB_val *key);
-
-static int	mdb_rebalance(MDB_cursor *mc);
-static int	mdb_update_key(MDB_cursor *mc, MDB_val *key);
-
-static void	mdb_cursor_pop(MDB_cursor *mc);
-static int	mdb_cursor_push(MDB_cursor *mc, MDB_page *mp);
-
-static int	mdb_cursor_del0(MDB_cursor *mc);
-static int	mdb_del0(MDB_txn *txn, MDB_dbi dbi, MDB_val *key, MDB_val *data, unsigned flags);
-static int	mdb_cursor_sibling(MDB_cursor *mc, int move_right);
-static int	mdb_cursor_next(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op);
-static int	mdb_cursor_prev(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op);
-static int	mdb_cursor_set(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op,
-				int *exactp);
-static int	mdb_cursor_first(MDB_cursor *mc, MDB_val *key, MDB_val *data);
-static int	mdb_cursor_last(MDB_cursor *mc, MDB_val *key, MDB_val *data);
-
-static void	mdb_cursor_init(MDB_cursor *mc, MDB_txn *txn, MDB_dbi dbi, MDB_xcursor *mx);
-static void	mdb_xcursor_init0(MDB_cursor *mc);
-static void	mdb_xcursor_init1(MDB_cursor *mc, MDB_node *node);
-static void	mdb_xcursor_init2(MDB_cursor *mc, MDB_xcursor *src_mx, int force);
-
-static int	mdb_drop0(MDB_cursor *mc, int subs);
-static void mdb_default_cmp(MDB_txn *txn, MDB_dbi dbi);
-static int mdb_reader_check0(MDB_env *env, int rlocked, int *dead);
-
-/** @cond */
-static MDB_cmp_func	mdb_cmp_memn, mdb_cmp_memnr, mdb_cmp_int, mdb_cmp_cint, mdb_cmp_long;
-/** @endcond */
-
-/** Compare two items pointing at size_t's of unknown alignment. */
-#ifdef MISALIGNED_OK
-# define mdb_cmp_clong mdb_cmp_long
-#else
-# define mdb_cmp_clong mdb_cmp_cint
-#endif
-
-#ifdef _WIN32
-static SECURITY_DESCRIPTOR mdb_null_sd;
-static SECURITY_ATTRIBUTES mdb_all_sa;
-static int mdb_sec_inited;
-
-static int utf8_to_utf16(const char *src, int srcsize, wchar_t **dst, int *dstsize);
-#endif
-
-/** Return the library version info. */
-char * ESECT
-mdb_version(int *major, int *minor, int *patch)
-{
-	if (major) *major = MDB_VERSION_MAJOR;
-	if (minor) *minor = MDB_VERSION_MINOR;
-	if (patch) *patch = MDB_VERSION_PATCH;
-	return MDB_VERSION_STRING;
-}
-
-/** Table of descriptions for LMDB @ref errors */
-static char *const mdb_errstr[] = {
-	"MDB_KEYEXIST: Key/data pair already exists",
-	"MDB_NOTFOUND: No matching key/data pair found",
-	"MDB_PAGE_NOTFOUND: Requested page not found",
-	"MDB_CORRUPTED: Located page was wrong type",
-	"MDB_PANIC: Update of meta page failed or environment had fatal error",
-	"MDB_VERSION_MISMATCH: Database environment version mismatch",
-	"MDB_INVALID: File is not an LMDB file",
-	"MDB_MAP_FULL: Environment mapsize limit reached",
-	"MDB_DBS_FULL: Environment maxdbs limit reached",
-	"MDB_READERS_FULL: Environment maxreaders limit reached",
-	"MDB_TLS_FULL: Thread-local storage keys full - too many environments open",
-	"MDB_TXN_FULL: Transaction has too many dirty pages - transaction too big",
-	"MDB_CURSOR_FULL: Internal error - cursor stack limit reached",
-	"MDB_PAGE_FULL: Internal error - page has no more space",
-	"MDB_MAP_RESIZED: Database contents grew beyond environment mapsize",
-	"MDB_INCOMPATIBLE: Operation and DB incompatible, or DB flags changed",
-	"MDB_BAD_RSLOT: Invalid reuse of reader locktable slot",
-	"MDB_BAD_TXN: Transaction must abort, has a child, or is invalid",
-	"MDB_BAD_VALSIZE: Unsupported size of key/DB name/data, or wrong DUPFIXED size",
-	"MDB_BAD_DBI: The specified DBI handle was closed/changed unexpectedly",
-};
-
-char *
-mdb_strerror(int err)
-{
-#ifdef _WIN32
-	/** HACK: pad 4KB on stack over the buf. Return system msgs in buf.
-	 *	This works as long as no function between the call to mdb_strerror
-	 *	and the actual use of the message uses more than 4K of stack.
-	 */
-#define MSGSIZE	1024
-#define PADSIZE	4096
-	char buf[MSGSIZE+PADSIZE], *ptr = buf;
-#endif
-	int i;
-	if (!err)
-		return ("Successful return: 0");
-
-	if (err >= MDB_KEYEXIST && err <= MDB_LAST_ERRCODE) {
-		i = err - MDB_KEYEXIST;
-		return mdb_errstr[i];
-	}
-
-#ifdef _WIN32
-	/* These are the C-runtime error codes we use. The comment indicates
-	 * their numeric value, and the Win32 error they would correspond to
-	 * if the error actually came from a Win32 API. A major mess, we should
-	 * have used LMDB-specific error codes for everything.
-	 */
-	switch(err) {
-	case ENOENT:	/* 2, FILE_NOT_FOUND */
-	case EIO:		/* 5, ACCESS_DENIED */
-	case ENOMEM:	/* 12, INVALID_ACCESS */
-	case EACCES:	/* 13, INVALID_DATA */
-	case EBUSY:		/* 16, CURRENT_DIRECTORY */
-	case EINVAL:	/* 22, BAD_COMMAND */
-	case ENOSPC:	/* 28, OUT_OF_PAPER */
-		return strerror(err);
-	default:
-		;
-	}
-	buf[0] = 0;
-	FormatMessageA(FORMAT_MESSAGE_FROM_SYSTEM |
-		FORMAT_MESSAGE_IGNORE_INSERTS,
-		NULL, err, 0, ptr, MSGSIZE, (va_list *)buf+MSGSIZE);
-	return ptr;
-#else
-	return strerror(err);
-#endif
-}
-
-/** assert(3) variant in cursor context */
-#define mdb_cassert(mc, expr)	mdb_assert0((mc)->mc_txn->mt_env, expr, #expr)
-/** assert(3) variant in transaction context */
-#define mdb_tassert(txn, expr)	mdb_assert0((txn)->mt_env, expr, #expr)
-/** assert(3) variant in environment context */
-#define mdb_eassert(env, expr)	mdb_assert0(env, expr, #expr)
-
-#ifndef NDEBUG
-# define mdb_assert0(env, expr, expr_txt) ((expr) ? (void)0 : \
-		mdb_assert_fail(env, expr_txt, mdb_func_, __FILE__, __LINE__))
-
-static void ESECT
-mdb_assert_fail(MDB_env *env, const char *expr_txt,
-	const char *func, const char *file, int line)
-{
-	char buf[400];
-	sprintf(buf, "%.100s:%d: Assertion '%.200s' failed in %.40s()",
-		file, line, expr_txt, func);
-	if (env->me_assert_func)
-		env->me_assert_func(env, buf);
-	fprintf(stderr, "%s\n", buf);
-	abort();
-}
-#else
-# define mdb_assert0(env, expr, expr_txt) ((void) 0)
-#endif /* NDEBUG */
-
-#if MDB_DEBUG
-/** Return the page number of \b mp which may be sub-page, for debug output */
-static pgno_t
-mdb_dbg_pgno(MDB_page *mp)
-{
-	pgno_t ret;
-	COPY_PGNO(ret, mp->mp_pgno);
-	return ret;
-}
-
-/** Display a key in hexadecimal and return the address of the result.
- * @param[in] key the key to display
- * @param[in] buf the buffer to write into. Should always be #DKBUF.
- * @return The key in hexadecimal form.
- */
-char *
-mdb_dkey(MDB_val *key, char *buf)
-{
-	char *ptr = buf;
-	unsigned char *c = key->mv_data;
-	unsigned int i;
-
-	if (!key)
-		return "";
-
-	if (key->mv_size > DKBUF_MAXKEYSIZE)
-		return "MDB_MAXKEYSIZE";
-	/* may want to make this a dynamic check: if the key is mostly
-	 * printable characters, print it as-is instead of converting to hex.
-	 */
-#if 1
-	buf[0] = '\0';
-	for (i=0; i<key->mv_size; i++)
-		ptr += sprintf(ptr, "%02x", *c++);
-#else
-	sprintf(buf, "%.*s", key->mv_size, key->mv_data);
-#endif
-	return buf;
-}
-
-static const char *
-mdb_leafnode_type(MDB_node *n)
-{
-	static char *const tp[2][2] = {{"", ": DB"}, {": sub-page", ": sub-DB"}};
-	return F_ISSET(n->mn_flags, F_BIGDATA) ? ": overflow page" :
-		tp[F_ISSET(n->mn_flags, F_DUPDATA)][F_ISSET(n->mn_flags, F_SUBDATA)];
-}
-
-/** Display all the keys in the page. */
-void
-mdb_page_list(MDB_page *mp)
-{
-	pgno_t pgno = mdb_dbg_pgno(mp);
-	const char *type, *state = (mp->mp_flags & P_DIRTY) ? ", dirty" : "";
-	MDB_node *node;
-	unsigned int i, nkeys, nsize, total = 0;
-	MDB_val key;
-	DKBUF;
-
-	switch (mp->mp_flags & (P_BRANCH|P_LEAF|P_LEAF2|P_META|P_OVERFLOW|P_SUBP)) {
-	case P_BRANCH:              type = "Branch page";		break;
-	case P_LEAF:                type = "Leaf page";			break;
-	case P_LEAF|P_SUBP:         type = "Sub-page";			break;
-	case P_LEAF|P_LEAF2:        type = "LEAF2 page";		break;
-	case P_LEAF|P_LEAF2|P_SUBP: type = "LEAF2 sub-page";	break;
-	case P_OVERFLOW:
-		fprintf(stderr, "Overflow page %"Y"u pages %u%s\n",
-			pgno, mp->mp_pages, state);
-		return;
-	case P_META:
-		fprintf(stderr, "Meta-page %"Y"u txnid %"Y"u\n",
-			pgno, ((MDB_meta *)METADATA(mp))->mm_txnid);
-		return;
-	default:
-		fprintf(stderr, "Bad page %"Y"u flags 0x%u\n", pgno, mp->mp_flags);
-		return;
-	}
-
-	nkeys = NUMKEYS(mp);
-	fprintf(stderr, "%s %"Y"u numkeys %d%s\n", type, pgno, nkeys, state);
-
-	for (i=0; i<nkeys; i++) {
-		if (IS_LEAF2(mp)) {	/* LEAF2 pages have no mp_ptrs[] or node headers */
-			key.mv_size = nsize = mp->mp_pad;
-			key.mv_data = LEAF2KEY(mp, i, nsize);
-			total += nsize;
-			fprintf(stderr, "key %d: nsize %d, %s\n", i, nsize, DKEY(&key));
-			continue;
-		}
-		node = NODEPTR(mp, i);
-		key.mv_size = node->mn_ksize;
-		key.mv_data = node->mn_data;
-		nsize = NODESIZE + key.mv_size;
-		if (IS_BRANCH(mp)) {
-			fprintf(stderr, "key %d: page %"Y"u, %s\n", i, NODEPGNO(node),
-				DKEY(&key));
-			total += nsize;
-		} else {
-			if (F_ISSET(node->mn_flags, F_BIGDATA))
-				nsize += sizeof(pgno_t);
-			else
-				nsize += NODEDSZ(node);
-			total += nsize;
-			nsize += sizeof(indx_t);
-			fprintf(stderr, "key %d: nsize %d, %s%s\n",
-				i, nsize, DKEY(&key), mdb_leafnode_type(node));
-		}
-		total = EVEN(total);
-	}
-	fprintf(stderr, "Total: header %d + contents %d + unused %d\n",
-		IS_LEAF2(mp) ? PAGEHDRSZ : PAGEBASE + mp->mp_lower, total, SIZELEFT(mp));
-}
-
-void
-mdb_cursor_chk(MDB_cursor *mc)
-{
-	unsigned int i;
-	MDB_node *node;
-	MDB_page *mp;
-
-	if (!mc->mc_snum || !(mc->mc_flags & C_INITIALIZED)) return;
-	for (i=0; i<mc->mc_top; i++) {
-		mp = mc->mc_pg[i];
-		node = NODEPTR(mp, mc->mc_ki[i]);
-		if (NODEPGNO(node) != mc->mc_pg[i+1]->mp_pgno)
-			printf("oops!\n");
-	}
-	if (mc->mc_ki[i] >= NUMKEYS(mc->mc_pg[i]))
-		printf("ack!\n");
-	if (mc->mc_xcursor && (mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED)) {
-		node = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
-		if (((node->mn_flags & (F_DUPDATA|F_SUBDATA)) == F_DUPDATA) &&
-			mc->mc_xcursor->mx_cursor.mc_pg[0] != NODEDATA(node)) {
-			printf("blah!\n");
-		}
-	}
-}
-#endif
-
-#if (MDB_DEBUG) > 2
-/** Count all the pages in each DB and in the freelist
- *  and make sure it matches the actual number of pages
- *  being used.
- *  All named DBs must be open for a correct count.
- */
-static void mdb_audit(MDB_txn *txn)
-{
-	MDB_cursor mc;
-	MDB_val key, data;
-	MDB_ID freecount, count;
-	MDB_dbi i;
-	int rc;
-
-	freecount = 0;
-	mdb_cursor_init(&mc, txn, FREE_DBI, NULL);
-	while ((rc = mdb_cursor_get(&mc, &key, &data, MDB_NEXT)) == 0)
-		freecount += *(MDB_ID *)data.mv_data;
-	mdb_tassert(txn, rc == MDB_NOTFOUND);
-
-	count = 0;
-	for (i = 0; i<txn->mt_numdbs; i++) {
-		MDB_xcursor mx;
-		if (!(txn->mt_dbflags[i] & DB_VALID))
-			continue;
-		mdb_cursor_init(&mc, txn, i, &mx);
-		if (txn->mt_dbs[i].md_root == P_INVALID)
-			continue;
-		count += txn->mt_dbs[i].md_branch_pages +
-			txn->mt_dbs[i].md_leaf_pages +
-			txn->mt_dbs[i].md_overflow_pages;
-		if (txn->mt_dbs[i].md_flags & MDB_DUPSORT) {
-			rc = mdb_page_search(&mc, NULL, MDB_PS_FIRST);
-			for (; rc == MDB_SUCCESS; rc = mdb_cursor_sibling(&mc, 1)) {
-				unsigned j;
-				MDB_page *mp;
-				mp = mc.mc_pg[mc.mc_top];
-				for (j=0; j<NUMKEYS(mp); j++) {
-					MDB_node *leaf = NODEPTR(mp, j);
-					if (leaf->mn_flags & F_SUBDATA) {
-						MDB_db db;
-						memcpy(&db, NODEDATA(leaf), sizeof(db));
-						count += db.md_branch_pages + db.md_leaf_pages +
-							db.md_overflow_pages;
-					}
-				}
-			}
-			mdb_tassert(txn, rc == MDB_NOTFOUND);
-		}
-	}
-	if (freecount + count + NUM_METAS != txn->mt_next_pgno) {
-		fprintf(stderr, "audit: %"Y"u freecount: %"Y"u count: %"Y"u total: %"Y"u next_pgno: %"Y"u\n",
-			txn->mt_txnid, freecount, count+NUM_METAS,
-			freecount+count+NUM_METAS, txn->mt_next_pgno);
-	}
-}
-#endif
-
-int
-mdb_cmp(MDB_txn *txn, MDB_dbi dbi, const MDB_val *a, const MDB_val *b)
-{
-	return txn->mt_dbxs[dbi].md_cmp(a, b);
-}
-
-int
-mdb_dcmp(MDB_txn *txn, MDB_dbi dbi, const MDB_val *a, const MDB_val *b)
-{
-	MDB_cmp_func *dcmp = txn->mt_dbxs[dbi].md_dcmp;
-#if UINT_MAX < SIZE_MAX || defined(MDB_VL32)
-	if (dcmp == mdb_cmp_int && a->mv_size == sizeof(mdb_size_t))
-		dcmp = mdb_cmp_clong;
-#endif
-	return dcmp(a, b);
-}
-
-/** Allocate memory for a page.
- * Re-use old malloc'd pages first for singletons, otherwise just malloc.
- */
-static MDB_page *
-mdb_page_malloc(MDB_txn *txn, unsigned num)
-{
-	MDB_env *env = txn->mt_env;
-	MDB_page *ret = env->me_dpages;
-	size_t psize = env->me_psize, sz = psize, off;
-	/* For ! #MDB_NOMEMINIT, psize counts how much to init.
-	 * For a single page alloc, we init everything after the page header.
-	 * For multi-page, we init the final page; if the caller needed that
-	 * many pages they will be filling in at least up to the last page.
-	 */
-	if (num == 1) {
-		if (ret) {
-			VGMEMP_ALLOC(env, ret, sz);
-			VGMEMP_DEFINED(ret, sizeof(ret->mp_next));
-			env->me_dpages = ret->mp_next;
-			return ret;
-		}
-		psize -= off = PAGEHDRSZ;
-	} else {
-		sz *= num;
-		off = sz - psize;
-	}
-	if ((ret = malloc(sz)) != NULL) {
-		VGMEMP_ALLOC(env, ret, sz);
-		if (!(env->me_flags & MDB_NOMEMINIT)) {
-			memset((char *)ret + off, 0, psize);
-			ret->mp_pad = 0;
-		}
-	} else {
-		txn->mt_flags |= MDB_TXN_ERROR;
-	}
-	return ret;
-}
-/** Free a single page.
- * Saves single pages to a list, for future reuse.
- * (This is not used for multi-page overflow pages.)
- */
-static void
-mdb_page_free(MDB_env *env, MDB_page *mp)
-{
-	mp->mp_next = env->me_dpages;
-	VGMEMP_FREE(env, mp);
-	env->me_dpages = mp;
-}
-
-/** Free a dirty page */
-static void
-mdb_dpage_free(MDB_env *env, MDB_page *dp)
-{
-	if (!IS_OVERFLOW(dp) || dp->mp_pages == 1) {
-		mdb_page_free(env, dp);
-	} else {
-		/* large pages just get freed directly */
-		VGMEMP_FREE(env, dp);
-		free(dp);
-	}
-}
-
-/**	Return all dirty pages to dpage list */
-static void
-mdb_dlist_free(MDB_txn *txn)
-{
-	MDB_env *env = txn->mt_env;
-	MDB_ID2L dl = txn->mt_u.dirty_list;
-	unsigned i, n = dl[0].mid;
-
-	for (i = 1; i <= n; i++) {
-		mdb_dpage_free(env, dl[i].mptr);
-	}
-	dl[0].mid = 0;
-}
-
-#ifdef MDB_VL32
-static void
-mdb_page_unref(MDB_txn *txn, MDB_page *mp)
-{
-	pgno_t pgno;
-	MDB_ID3L tl = txn->mt_rpages;
-	unsigned x, rem;
-	if (mp->mp_flags & (P_SUBP|P_DIRTY))
-		return;
-	rem = mp->mp_pgno & (MDB_RPAGE_CHUNK-1);
-	pgno = mp->mp_pgno ^ rem;
-	x = mdb_mid3l_search(tl, pgno);
-	if (x != tl[0].mid && tl[x+1].mid == mp->mp_pgno)
-		x++;
-	if (tl[x].mref)
-		tl[x].mref--;
-}
-#define MDB_PAGE_UNREF(txn, mp)	mdb_page_unref(txn, mp)
-
-static void
-mdb_cursor_unref(MDB_cursor *mc)
-{
-	int i;
-	if (!mc->mc_snum || !mc->mc_pg[0] || IS_SUBP(mc->mc_pg[0]))
-		return;
-	for (i=0; i<mc->mc_snum; i++)
-		mdb_page_unref(mc->mc_txn, mc->mc_pg[i]);
-	if (mc->mc_ovpg) {
-		mdb_page_unref(mc->mc_txn, mc->mc_ovpg);
-		mc->mc_ovpg = 0;
-	}
-	mc->mc_snum = mc->mc_top = 0;
-	mc->mc_pg[0] = NULL;
-	mc->mc_flags &= ~C_INITIALIZED;
-}
-#else
-#define MDB_PAGE_UNREF(txn, mp)
-#endif /* MDB_VL32 */
-
-/** Loosen or free a single page.
- * Saves single pages to a list for future reuse
- * in this same txn. It has been pulled from the freeDB
- * and already resides on the dirty list, but has been
- * deleted. Use these pages first before pulling again
- * from the freeDB.
- *
- * If the page wasn't dirtied in this txn, just add it
- * to this txn's free list.
- */
-static int
-mdb_page_loose(MDB_cursor *mc, MDB_page *mp)
-{
-	int loose = 0;
-	pgno_t pgno = mp->mp_pgno;
-	MDB_txn *txn = mc->mc_txn;
-
-	if ((mp->mp_flags & P_DIRTY) && mc->mc_dbi != FREE_DBI) {
-		if (txn->mt_parent) {
-			MDB_ID2 *dl = txn->mt_u.dirty_list;
-			/* If txn has a parent, make sure the page is in our
-			 * dirty list.
-			 */
-			if (dl[0].mid) {
-				unsigned x = mdb_mid2l_search(dl, pgno);
-				if (x <= dl[0].mid && dl[x].mid == pgno) {
-					if (mp != dl[x].mptr) { /* bad cursor? */
-						mc->mc_flags &= ~(C_INITIALIZED|C_EOF);
-						txn->mt_flags |= MDB_TXN_ERROR;
-						return MDB_CORRUPTED;
-					}
-					/* ok, it's ours */
-					loose = 1;
-				}
-			}
-		} else {
-			/* no parent txn, so it's just ours */
-			loose = 1;
-		}
-	}
-	if (loose) {
-		DPRINTF(("loosen db %d page %"Y"u", DDBI(mc),
-			mp->mp_pgno));
-		NEXT_LOOSE_PAGE(mp) = txn->mt_loose_pgs;
-		txn->mt_loose_pgs = mp;
-		txn->mt_loose_count++;
-		mp->mp_flags |= P_LOOSE;
-	} else {
-		int rc = mdb_midl_append(&txn->mt_free_pgs, pgno);
-		if (rc)
-			return rc;
-	}
-
-	return MDB_SUCCESS;
-}
-
-/** Set or clear P_KEEP in dirty, non-overflow, non-sub pages watched by txn.
- * @param[in] mc A cursor handle for the current operation.
- * @param[in] pflags Flags of the pages to update:
- * P_DIRTY to set P_KEEP, P_DIRTY|P_KEEP to clear it.
- * @param[in] all No shortcuts. Needed except after a full #mdb_page_flush().
- * @return 0 on success, non-zero on failure.
- */
-static int
-mdb_pages_xkeep(MDB_cursor *mc, unsigned pflags, int all)
-{
-	enum { Mask = P_SUBP|P_DIRTY|P_LOOSE|P_KEEP };
-	MDB_txn *txn = mc->mc_txn;
-	MDB_cursor *m3, *m0 = mc;
-	MDB_xcursor *mx;
-	MDB_page *dp, *mp;
-	MDB_node *leaf;
-	unsigned i, j;
-	int rc = MDB_SUCCESS, level;
-
-	/* Mark pages seen by cursors */
-	if (mc->mc_flags & C_UNTRACK)
-		mc = NULL;				/* will find mc in mt_cursors */
-	for (i = txn->mt_numdbs;; mc = txn->mt_cursors[--i]) {
-		for (; mc; mc=mc->mc_next) {
-			if (!(mc->mc_flags & C_INITIALIZED))
-				continue;
-			for (m3 = mc;; m3 = &mx->mx_cursor) {
-				mp = NULL;
-				for (j=0; j<m3->mc_snum; j++) {
-					mp = m3->mc_pg[j];
-					if ((mp->mp_flags & Mask) == pflags)
-						mp->mp_flags ^= P_KEEP;
-				}
-				mx = m3->mc_xcursor;
-				/* Proceed to mx if it is at a sub-database */
-				if (! (mx && (mx->mx_cursor.mc_flags & C_INITIALIZED)))
-					break;
-				if (! (mp && (mp->mp_flags & P_LEAF)))
-					break;
-				leaf = NODEPTR(mp, m3->mc_ki[j-1]);
-				if (!(leaf->mn_flags & F_SUBDATA))
-					break;
-			}
-		}
-		if (i == 0)
-			break;
-	}
-
-	if (all) {
-		/* Mark dirty root pages */
-		for (i=0; i<txn->mt_numdbs; i++) {
-			if (txn->mt_dbflags[i] & DB_DIRTY) {
-				pgno_t pgno = txn->mt_dbs[i].md_root;
-				if (pgno == P_INVALID)
-					continue;
-				if ((rc = mdb_page_get(m0, pgno, &dp, &level)) != MDB_SUCCESS)
-					break;
-				if ((dp->mp_flags & Mask) == pflags && level <= 1)
-					dp->mp_flags ^= P_KEEP;
-			}
-		}
-	}
-
-	return rc;
-}
-
-static int mdb_page_flush(MDB_txn *txn, int keep);
-
-/**	Spill pages from the dirty list back to disk.
- * This is intended to prevent running into #MDB_TXN_FULL situations,
- * but note that they may still occur in a few cases:
- *	1) our estimate of the txn size could be too small. Currently this
- *	 seems unlikely, except with a large number of #MDB_MULTIPLE items.
- *	2) child txns may run out of space if their parents dirtied a
- *	 lot of pages and never spilled them. TODO: we probably should do
- *	 a preemptive spill during #mdb_txn_begin() of a child txn, if
- *	 the parent's dirty_room is below a given threshold.
- *
- * Otherwise, if not using nested txns, it is expected that apps will
- * not run into #MDB_TXN_FULL any more. The pages are flushed to disk
- * the same way as for a txn commit, e.g. their P_DIRTY flag is cleared.
- * If the txn never references them again, they can be left alone.
- * If the txn only reads them, they can be used without any fuss.
- * If the txn writes them again, they can be dirtied immediately without
- * going thru all of the work of #mdb_page_touch(). Such references are
- * handled by #mdb_page_unspill().
- *
- * Also note, we never spill DB root pages, nor pages of active cursors,
- * because we'll need these back again soon anyway. And in nested txns,
- * we can't spill a page in a child txn if it was already spilled in a
- * parent txn. That would alter the parent txns' data even though
- * the child hasn't committed yet, and we'd have no way to undo it if
- * the child aborted.
- *
- * @param[in] m0 cursor A cursor handle identifying the transaction and
- *	database for which we are checking space.
- * @param[in] key For a put operation, the key being stored.
- * @param[in] data For a put operation, the data being stored.
- * @return 0 on success, non-zero on failure.
- */
-static int
-mdb_page_spill(MDB_cursor *m0, MDB_val *key, MDB_val *data)
-{
-	MDB_txn *txn = m0->mc_txn;
-	MDB_page *dp;
-	MDB_ID2L dl = txn->mt_u.dirty_list;
-	unsigned int i, j, need;
-	int rc;
-
-	if (m0->mc_flags & C_SUB)
-		return MDB_SUCCESS;
-
-	/* Estimate how much space this op will take */
-	i = m0->mc_db->md_depth;
-	/* Named DBs also dirty the main DB */
-	if (m0->mc_dbi >= CORE_DBS)
-		i += txn->mt_dbs[MAIN_DBI].md_depth;
-	/* For puts, roughly factor in the key+data size */
-	if (key)
-		i += (LEAFSIZE(key, data) + txn->mt_env->me_psize) / txn->mt_env->me_psize;
-	i += i;	/* double it for good measure */
-	need = i;
-
-	if (txn->mt_dirty_room > i)
-		return MDB_SUCCESS;
-
-	if (!txn->mt_spill_pgs) {
-		txn->mt_spill_pgs = mdb_midl_alloc(MDB_IDL_UM_MAX);
-		if (!txn->mt_spill_pgs)
-			return ENOMEM;
-	} else {
-		/* purge deleted slots */
-		MDB_IDL sl = txn->mt_spill_pgs;
-		unsigned int num = sl[0];
-		j=0;
-		for (i=1; i<=num; i++) {
-			if (!(sl[i] & 1))
-				sl[++j] = sl[i];
-		}
-		sl[0] = j;
-	}
-
-	/* Preserve pages which may soon be dirtied again */
-	if ((rc = mdb_pages_xkeep(m0, P_DIRTY, 1)) != MDB_SUCCESS)
-		goto done;
-
-	/* Less aggressive spill - we originally spilled the entire dirty list,
-	 * with a few exceptions for cursor pages and DB root pages. But this
-	 * turns out to be a lot of wasted effort because in a large txn many
-	 * of those pages will need to be used again. So now we spill only 1/8th
-	 * of the dirty pages. Testing revealed this to be a good tradeoff,
-	 * better than 1/2, 1/4, or 1/10.
-	 */
-	if (need < MDB_IDL_UM_MAX / 8)
-		need = MDB_IDL_UM_MAX / 8;
-
-	/* Save the page IDs of all the pages we're flushing */
-	/* flush from the tail forward, this saves a lot of shifting later on. */
-	for (i=dl[0].mid; i && need; i--) {
-		MDB_ID pn = dl[i].mid << 1;
-		dp = dl[i].mptr;
-		if (dp->mp_flags & (P_LOOSE|P_KEEP))
-			continue;
-		/* Can't spill twice, make sure it's not already in a parent's
-		 * spill list.
-		 */
-		if (txn->mt_parent) {
-			MDB_txn *tx2;
-			for (tx2 = txn->mt_parent; tx2; tx2 = tx2->mt_parent) {
-				if (tx2->mt_spill_pgs) {
-					j = mdb_midl_search(tx2->mt_spill_pgs, pn);
-					if (j <= tx2->mt_spill_pgs[0] && tx2->mt_spill_pgs[j] == pn) {
-						dp->mp_flags |= P_KEEP;
-						break;
-					}
-				}
-			}
-			if (tx2)
-				continue;
-		}
-		if ((rc = mdb_midl_append(&txn->mt_spill_pgs, pn)))
-			goto done;
-		need--;
-	}
-	mdb_midl_sort(txn->mt_spill_pgs);
-
-	/* Flush the spilled part of dirty list */
-	if ((rc = mdb_page_flush(txn, i)) != MDB_SUCCESS)
-		goto done;
-
-	/* Reset any dirty pages we kept that page_flush didn't see */
-	rc = mdb_pages_xkeep(m0, P_DIRTY|P_KEEP, i);
-
-done:
-	txn->mt_flags |= rc ? MDB_TXN_ERROR : MDB_TXN_SPILLS;
-	return rc;
-}
-
-/** Find oldest txnid still referenced. Expects txn->mt_txnid > 0. */
-static txnid_t
-mdb_find_oldest(MDB_txn *txn)
-{
-	int i;
-	txnid_t mr, oldest = txn->mt_txnid - 1;
-	if (txn->mt_env->me_txns) {
-		MDB_reader *r = txn->mt_env->me_txns->mti_readers;
-		for (i = txn->mt_env->me_txns->mti_numreaders; --i >= 0; ) {
-			if (r[i].mr_pid) {
-				mr = r[i].mr_txnid;
-				if (oldest > mr)
-					oldest = mr;
-			}
-		}
-	}
-	return oldest;
-}
-
-/** Add a page to the txn's dirty list */
-static void
-mdb_page_dirty(MDB_txn *txn, MDB_page *mp)
-{
-	MDB_ID2 mid;
-	int rc, (*insert)(MDB_ID2L, MDB_ID2 *);
-
-	if (txn->mt_flags & MDB_TXN_WRITEMAP) {
-		insert = mdb_mid2l_append;
-	} else {
-		insert = mdb_mid2l_insert;
-	}
-	mid.mid = mp->mp_pgno;
-	mid.mptr = mp;
-	rc = insert(txn->mt_u.dirty_list, &mid);
-	mdb_tassert(txn, rc == 0);
-	txn->mt_dirty_room--;
-}
-
-/** Allocate page numbers and memory for writing.  Maintain me_pglast,
- * me_pghead and mt_next_pgno.
- *
- * If there are free pages available from older transactions, they
- * are re-used first. Otherwise allocate a new page at mt_next_pgno.
- * Do not modify the freedB, just merge freeDB records into me_pghead[]
- * and move me_pglast to say which records were consumed.  Only this
- * function can create me_pghead and move me_pglast/mt_next_pgno.
- * When #MDB_DEVEL & 2, it is not affected by #mdb_freelist_save(): it
- * then uses the transaction's original snapshot of the freeDB.
- * @param[in] mc cursor A cursor handle identifying the transaction and
- *	database for which we are allocating.
- * @param[in] num the number of pages to allocate.
- * @param[out] mp Address of the allocated page(s). Requests for multiple pages
- *  will always be satisfied by a single contiguous chunk of memory.
- * @return 0 on success, non-zero on failure.
- */
-static int
-mdb_page_alloc(MDB_cursor *mc, int num, MDB_page **mp)
-{
-#ifdef MDB_PARANOID	/* Seems like we can ignore this now */
-	/* Get at most <Max_retries> more freeDB records once me_pghead
-	 * has enough pages.  If not enough, use new pages from the map.
-	 * If <Paranoid> and mc is updating the freeDB, only get new
-	 * records if me_pghead is empty. Then the freelist cannot play
-	 * catch-up with itself by growing while trying to save it.
-	 */
-	enum { Paranoid = 1, Max_retries = 500 };
-#else
-	enum { Paranoid = 0, Max_retries = INT_MAX /*infinite*/ };
-#endif
-	int rc, retry = num * 60;
-	MDB_txn *txn = mc->mc_txn;
-	MDB_env *env = txn->mt_env;
-	pgno_t pgno, *mop = env->me_pghead;
-	unsigned i, j, mop_len = mop ? mop[0] : 0, n2 = num-1;
-	MDB_page *np;
-	txnid_t oldest = 0, last;
-	MDB_cursor_op op;
-	MDB_cursor m2;
-	int found_old = 0;
-
-	/* If there are any loose pages, just use them */
-	if (num == 1 && txn->mt_loose_pgs) {
-		np = txn->mt_loose_pgs;
-		txn->mt_loose_pgs = NEXT_LOOSE_PAGE(np);
-		txn->mt_loose_count--;
-		DPRINTF(("db %d use loose page %"Y"u", DDBI(mc),
-				np->mp_pgno));
-		*mp = np;
-		return MDB_SUCCESS;
-	}
-
-	*mp = NULL;
-
-	/* If our dirty list is already full, we can't do anything */
-	if (txn->mt_dirty_room == 0) {
-		rc = MDB_TXN_FULL;
-		goto fail;
-	}
-
-	for (op = MDB_FIRST;; op = MDB_NEXT) {
-		MDB_val key, data;
-		MDB_node *leaf;
-		pgno_t *idl;
-
-		/* Seek a big enough contiguous page range. Prefer
-		 * pages at the tail, just truncating the list.
-		 */
-		if (mop_len > n2) {
-			i = mop_len;
-			do {
-				pgno = mop[i];
-				if (mop[i-n2] == pgno+n2)
-					goto search_done;
-			} while (--i > n2);
-			if (--retry < 0)
-				break;
-		}
-
-		if (op == MDB_FIRST) {	/* 1st iteration */
-			/* Prepare to fetch more and coalesce */
-			last = env->me_pglast;
-			oldest = env->me_pgoldest;
-			mdb_cursor_init(&m2, txn, FREE_DBI, NULL);
-#if (MDB_DEVEL) & 2	/* "& 2" so MDB_DEVEL=1 won't hide bugs breaking freeDB */
-			/* Use original snapshot. TODO: Should need less care in code
-			 * which modifies the database. Maybe we can delete some code?
-			 */
-			m2.mc_flags |= C_ORIG_RDONLY;
-			m2.mc_db = &env->me_metas[(txn->mt_txnid-1) & 1]->mm_dbs[FREE_DBI];
-			m2.mc_dbflag = (unsigned char *)""; /* probably unnecessary */
-#endif
-			if (last) {
-				op = MDB_SET_RANGE;
-				key.mv_data = &last; /* will look up last+1 */
-				key.mv_size = sizeof(last);
-			}
-			if (Paranoid && mc->mc_dbi == FREE_DBI)
-				retry = -1;
-		}
-		if (Paranoid && retry < 0 && mop_len)
-			break;
-
-		last++;
-		/* Do not fetch more if the record will be too recent */
-		if (oldest <= last) {
-			if (!found_old) {
-				oldest = mdb_find_oldest(txn);
-				env->me_pgoldest = oldest;
-				found_old = 1;
-			}
-			if (oldest <= last)
-				break;
-		}
-		rc = mdb_cursor_get(&m2, &key, NULL, op);
-		if (rc) {
-			if (rc == MDB_NOTFOUND)
-				break;
-			goto fail;
-		}
-		last = *(txnid_t*)key.mv_data;
-		if (oldest <= last) {
-			if (!found_old) {
-				oldest = mdb_find_oldest(txn);
-				env->me_pgoldest = oldest;
-				found_old = 1;
-			}
-			if (oldest <= last)
-				break;
-		}
-		np = m2.mc_pg[m2.mc_top];
-		leaf = NODEPTR(np, m2.mc_ki[m2.mc_top]);
-		if ((rc = mdb_node_read(&m2, leaf, &data)) != MDB_SUCCESS)
-			return rc;
-
-		idl = (MDB_ID *) data.mv_data;
-		i = idl[0];
-		if (!mop) {
-			if (!(env->me_pghead = mop = mdb_midl_alloc(i))) {
-				rc = ENOMEM;
-				goto fail;
-			}
-		} else {
-			if ((rc = mdb_midl_need(&env->me_pghead, i)) != 0)
-				goto fail;
-			mop = env->me_pghead;
-		}
-		env->me_pglast = last;
-#if (MDB_DEBUG) > 1
-		DPRINTF(("IDL read txn %"Y"u root %"Y"u num %u",
-			last, txn->mt_dbs[FREE_DBI].md_root, i));
-		for (j = i; j; j--)
-			DPRINTF(("IDL %"Y"u", idl[j]));
-#endif
-		/* Merge in descending sorted order */
-		mdb_midl_xmerge(mop, idl);
-		mop_len = mop[0];
-	}
-
-	/* Use new pages from the map when nothing suitable in the freeDB */
-	i = 0;
-	pgno = txn->mt_next_pgno;
-	if (pgno + num >= env->me_maxpg) {
-			DPUTS("DB size maxed out");
-			rc = MDB_MAP_FULL;
-			goto fail;
-	}
-#if defined(_WIN32) && !defined(MDB_VL32)
-	if (!(env->me_flags & MDB_RDONLY)) {
-		void *p;
-		p = (MDB_page *)(env->me_map + env->me_psize * pgno);
-		p = VirtualAlloc(p, env->me_psize * num, MEM_COMMIT,
-			(env->me_flags & MDB_WRITEMAP) ? PAGE_READWRITE:
-			PAGE_READONLY);
-		if (!p) {
-			DPUTS("VirtualAlloc failed");
-			rc = ErrCode();
-			goto fail;
-		}
-	}
-#endif
-
-search_done:
-	if (env->me_flags & MDB_WRITEMAP) {
-		np = (MDB_page *)(env->me_map + env->me_psize * pgno);
-	} else {
-		if (!(np = mdb_page_malloc(txn, num))) {
-			rc = ENOMEM;
-			goto fail;
-		}
-	}
-	if (i) {
-		mop[0] = mop_len -= num;
-		/* Move any stragglers down */
-		for (j = i-num; j < mop_len; )
-			mop[++j] = mop[++i];
-	} else {
-		txn->mt_next_pgno = pgno + num;
-	}
-	np->mp_pgno = pgno;
-	mdb_page_dirty(txn, np);
-	*mp = np;
-
-	return MDB_SUCCESS;
-
-fail:
-	txn->mt_flags |= MDB_TXN_ERROR;
-	return rc;
-}
-
-/** Copy the used portions of a non-overflow page.
- * @param[in] dst page to copy into
- * @param[in] src page to copy from
- * @param[in] psize size of a page
- */
-static void
-mdb_page_copy(MDB_page *dst, MDB_page *src, unsigned int psize)
-{
-	enum { Align = sizeof(pgno_t) };
-	indx_t upper = src->mp_upper, lower = src->mp_lower, unused = upper-lower;
-
-	/* If page isn't full, just copy the used portion. Adjust
-	 * alignment so memcpy may copy words instead of bytes.
-	 */
-	if ((unused &= -Align) && !IS_LEAF2(src)) {
-		upper = (upper + PAGEBASE) & -Align;
-		memcpy(dst, src, (lower + PAGEBASE + (Align-1)) & -Align);
-		memcpy((pgno_t *)((char *)dst+upper), (pgno_t *)((char *)src+upper),
-			psize - upper);
-	} else {
-		memcpy(dst, src, psize - unused);
-	}
-}
-
-/** Pull a page off the txn's spill list, if present.
- * If a page being referenced was spilled to disk in this txn, bring
- * it back and make it dirty/writable again.
- * @param[in] txn the transaction handle.
- * @param[in] mp the page being referenced. It must not be dirty.
- * @param[out] ret the writable page, if any. ret is unchanged if
- * mp wasn't spilled.
- */
-static int
-mdb_page_unspill(MDB_txn *txn, MDB_page *mp, MDB_page **ret)
-{
-	MDB_env *env = txn->mt_env;
-	const MDB_txn *tx2;
-	unsigned x;
-	pgno_t pgno = mp->mp_pgno, pn = pgno << 1;
-
-	for (tx2 = txn; tx2; tx2=tx2->mt_parent) {
-		if (!tx2->mt_spill_pgs)
-			continue;
-		x = mdb_midl_search(tx2->mt_spill_pgs, pn);
-		if (x <= tx2->mt_spill_pgs[0] && tx2->mt_spill_pgs[x] == pn) {
-			MDB_page *np;
-			int num;
-			if (txn->mt_dirty_room == 0)
-				return MDB_TXN_FULL;
-			if (IS_OVERFLOW(mp))
-				num = mp->mp_pages;
-			else
-				num = 1;
-			if (env->me_flags & MDB_WRITEMAP) {
-				np = mp;
-			} else {
-				np = mdb_page_malloc(txn, num);
-				if (!np)
-					return ENOMEM;
-				if (num > 1)
-					memcpy(np, mp, num * env->me_psize);
-				else
-					mdb_page_copy(np, mp, env->me_psize);
-			}
-			if (tx2 == txn) {
-				/* If in current txn, this page is no longer spilled.
-				 * If it happens to be the last page, truncate the spill list.
-				 * Otherwise mark it as deleted by setting the LSB.
-				 */
-				if (x == txn->mt_spill_pgs[0])
-					txn->mt_spill_pgs[0]--;
-				else
-					txn->mt_spill_pgs[x] |= 1;
-			}	/* otherwise, if belonging to a parent txn, the
-				 * page remains spilled until child commits
-				 */
-
-			mdb_page_dirty(txn, np);
-			np->mp_flags |= P_DIRTY;
-			*ret = np;
-			break;
-		}
-	}
-	return MDB_SUCCESS;
-}
-
-/** Touch a page: make it dirty and re-insert into tree with updated pgno.
- * @param[in] mc cursor pointing to the page to be touched
- * @return 0 on success, non-zero on failure.
- */
-static int
-mdb_page_touch(MDB_cursor *mc)
-{
-	MDB_page *mp = mc->mc_pg[mc->mc_top], *np;
-	MDB_txn *txn = mc->mc_txn;
-	MDB_cursor *m2, *m3;
-	pgno_t	pgno;
-	int rc;
-
-	if (!F_ISSET(mp->mp_flags, P_DIRTY)) {
-		if (txn->mt_flags & MDB_TXN_SPILLS) {
-			np = NULL;
-			rc = mdb_page_unspill(txn, mp, &np);
-			if (rc)
-				goto fail;
-			if (np)
-				goto done;
-		}
-		if ((rc = mdb_midl_need(&txn->mt_free_pgs, 1)) ||
-			(rc = mdb_page_alloc(mc, 1, &np)))
-			goto fail;
-		pgno = np->mp_pgno;
-		DPRINTF(("touched db %d page %"Y"u -> %"Y"u", DDBI(mc),
-			mp->mp_pgno, pgno));
-		mdb_cassert(mc, mp->mp_pgno != pgno);
-		mdb_midl_xappend(txn->mt_free_pgs, mp->mp_pgno);
-		/* Update the parent page, if any, to point to the new page */
-		if (mc->mc_top) {
-			MDB_page *parent = mc->mc_pg[mc->mc_top-1];
-			MDB_node *node = NODEPTR(parent, mc->mc_ki[mc->mc_top-1]);
-			SETPGNO(node, pgno);
-		} else {
-			mc->mc_db->md_root = pgno;
-		}
-	} else if (txn->mt_parent && !IS_SUBP(mp)) {
-		MDB_ID2 mid, *dl = txn->mt_u.dirty_list;
-		pgno = mp->mp_pgno;
-		/* If txn has a parent, make sure the page is in our
-		 * dirty list.
-		 */
-		if (dl[0].mid) {
-			unsigned x = mdb_mid2l_search(dl, pgno);
-			if (x <= dl[0].mid && dl[x].mid == pgno) {
-				if (mp != dl[x].mptr) { /* bad cursor? */
-					mc->mc_flags &= ~(C_INITIALIZED|C_EOF);
-					txn->mt_flags |= MDB_TXN_ERROR;
-					return MDB_CORRUPTED;
-				}
-				return 0;
-			}
-		}
-		mdb_cassert(mc, dl[0].mid < MDB_IDL_UM_MAX);
-		/* No - copy it */
-		np = mdb_page_malloc(txn, 1);
-		if (!np)
-			return ENOMEM;
-		mid.mid = pgno;
-		mid.mptr = np;
-		rc = mdb_mid2l_insert(dl, &mid);
-		mdb_cassert(mc, rc == 0);
-	} else {
-		return 0;
-	}
-
-	mdb_page_copy(np, mp, txn->mt_env->me_psize);
-	np->mp_pgno = pgno;
-	np->mp_flags |= P_DIRTY;
-
-done:
-	/* Adjust cursors pointing to mp */
-	mc->mc_pg[mc->mc_top] = np;
-	m2 = txn->mt_cursors[mc->mc_dbi];
-	if (mc->mc_flags & C_SUB) {
-		for (; m2; m2=m2->mc_next) {
-			m3 = &m2->mc_xcursor->mx_cursor;
-			if (m3->mc_snum < mc->mc_snum) continue;
-			if (m3->mc_pg[mc->mc_top] == mp)
-				m3->mc_pg[mc->mc_top] = np;
-		}
-	} else {
-		for (; m2; m2=m2->mc_next) {
-			if (m2->mc_snum < mc->mc_snum) continue;
-			if (m2 == mc) continue;
-			if (m2->mc_pg[mc->mc_top] == mp) {
-				m2->mc_pg[mc->mc_top] = np;
-				if ((mc->mc_db->md_flags & MDB_DUPSORT) &&
-					IS_LEAF(np) &&
-					(m2->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED))
-				{
-					MDB_node *leaf = NODEPTR(np, m2->mc_ki[mc->mc_top]);
-					if ((leaf->mn_flags & (F_DUPDATA|F_SUBDATA)) == F_DUPDATA)
-						m2->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(leaf);
-				}
-			}
-		}
-	}
-	MDB_PAGE_UNREF(mc->mc_txn, mp);
-	return 0;
-
-fail:
-	txn->mt_flags |= MDB_TXN_ERROR;
-	return rc;
-}
-
-int
-mdb_env_sync0(MDB_env *env, int force, pgno_t numpgs)
-{
-	int rc = 0;
-	if (env->me_flags & MDB_RDONLY)
-		return EACCES;
-	if (force || !F_ISSET(env->me_flags, MDB_NOSYNC)) {
-		if (env->me_flags & MDB_WRITEMAP) {
-			int flags = ((env->me_flags & MDB_MAPASYNC) && !force)
-				? MS_ASYNC : MS_SYNC;
-			if (MDB_MSYNC(env->me_map, env->me_psize * numpgs, flags))
-				rc = ErrCode();
-#ifdef _WIN32
-			else if (flags == MS_SYNC && MDB_FDATASYNC(env->me_fd))
-				rc = ErrCode();
-#endif
-		} else {
-#ifdef BROKEN_FDATASYNC
-			if (env->me_flags & MDB_FSYNCONLY) {
-				if (fsync(env->me_fd))
-					rc = ErrCode();
-			} else
-#endif
-			if (MDB_FDATASYNC(env->me_fd))
-				rc = ErrCode();
-		}
-	}
-	return rc;
-}
-
-int
-mdb_env_sync(MDB_env *env, int force)
-{
-	MDB_meta *m = mdb_env_pick_meta(env);
-	return mdb_env_sync0(env, force, m->mm_last_pg+1);
-}
-
-/** Back up parent txn's cursors, then grab the originals for tracking */
-static int
-mdb_cursor_shadow(MDB_txn *src, MDB_txn *dst)
-{
-	MDB_cursor *mc, *bk;
-	MDB_xcursor *mx;
-	size_t size;
-	int i;
-
-	for (i = src->mt_numdbs; --i >= 0; ) {
-		if ((mc = src->mt_cursors[i]) != NULL) {
-			size = sizeof(MDB_cursor);
-			if (mc->mc_xcursor)
-				size += sizeof(MDB_xcursor);
-			for (; mc; mc = bk->mc_next) {
-				bk = malloc(size);
-				if (!bk)
-					return ENOMEM;
-				*bk = *mc;
-				mc->mc_backup = bk;
-				mc->mc_db = &dst->mt_dbs[i];
-				/* Kill pointers into src to reduce abuse: The
-				 * user may not use mc until dst ends. But we need a valid
-				 * txn pointer here for cursor fixups to keep working.
-				 */
-				mc->mc_txn    = dst;
-				mc->mc_dbflag = &dst->mt_dbflags[i];
-				if ((mx = mc->mc_xcursor) != NULL) {
-					*(MDB_xcursor *)(bk+1) = *mx;
-					mx->mx_cursor.mc_txn = dst;
-				}
-				mc->mc_next = dst->mt_cursors[i];
-				dst->mt_cursors[i] = mc;
-			}
-		}
-	}
-	return MDB_SUCCESS;
-}
-
-/** Close this write txn's cursors, give parent txn's cursors back to parent.
- * @param[in] txn the transaction handle.
- * @param[in] merge true to keep changes to parent cursors, false to revert.
- * @return 0 on success, non-zero on failure.
- */
-static void
-mdb_cursors_close(MDB_txn *txn, unsigned merge)
-{
-	MDB_cursor **cursors = txn->mt_cursors, *mc, *next, *bk;
-	MDB_xcursor *mx;
-	int i;
-
-	for (i = txn->mt_numdbs; --i >= 0; ) {
-		for (mc = cursors[i]; mc; mc = next) {
-			next = mc->mc_next;
-			if ((bk = mc->mc_backup) != NULL) {
-				if (merge) {
-					/* Commit changes to parent txn */
-					mc->mc_next = bk->mc_next;
-					mc->mc_backup = bk->mc_backup;
-					mc->mc_txn = bk->mc_txn;
-					mc->mc_db = bk->mc_db;
-					mc->mc_dbflag = bk->mc_dbflag;
-					if ((mx = mc->mc_xcursor) != NULL)
-						mx->mx_cursor.mc_txn = bk->mc_txn;
-				} else {
-					/* Abort nested txn */
-					*mc = *bk;
-					if ((mx = mc->mc_xcursor) != NULL)
-						*mx = *(MDB_xcursor *)(bk+1);
-				}
-				mc = bk;
-			}
-			/* Only malloced cursors are permanently tracked. */
-			free(mc);
-		}
-		cursors[i] = NULL;
-	}
-}
-
-#if !(MDB_PIDLOCK)		/* Currently the same as defined(_WIN32) */
-enum Pidlock_op {
-	Pidset, Pidcheck
-};
-#else
-enum Pidlock_op {
-	Pidset = F_SETLK, Pidcheck = F_GETLK
-};
-#endif
-
-/** Set or check a pid lock. Set returns 0 on success.
- * Check returns 0 if the process is certainly dead, nonzero if it may
- * be alive (the lock exists or an error happened so we do not know).
- *
- * On Windows Pidset is a no-op, we merely check for the existence
- * of the process with the given pid. On POSIX we use a single byte
- * lock on the lockfile, set at an offset equal to the pid.
- */
-static int
-mdb_reader_pid(MDB_env *env, enum Pidlock_op op, MDB_PID_T pid)
-{
-#if !(MDB_PIDLOCK)		/* Currently the same as defined(_WIN32) */
-	int ret = 0;
-	HANDLE h;
-	if (op == Pidcheck) {
-		h = OpenProcess(env->me_pidquery, FALSE, pid);
-		/* No documented "no such process" code, but other program use this: */
-		if (!h)
-			return ErrCode() != ERROR_INVALID_PARAMETER;
-		/* A process exists until all handles to it close. Has it exited? */
-		ret = WaitForSingleObject(h, 0) != 0;
-		CloseHandle(h);
-	}
-	return ret;
-#else
-	for (;;) {
-		int rc;
-		struct flock lock_info;
-		memset(&lock_info, 0, sizeof(lock_info));
-		lock_info.l_type = F_WRLCK;
-		lock_info.l_whence = SEEK_SET;
-		lock_info.l_start = pid;
-		lock_info.l_len = 1;
-		if ((rc = fcntl(env->me_lfd, op, &lock_info)) == 0) {
-			if (op == F_GETLK && lock_info.l_type != F_UNLCK)
-				rc = -1;
-		} else if ((rc = ErrCode()) == EINTR) {
-			continue;
-		}
-		return rc;
-	}
-#endif
-}
-
-/** Common code for #mdb_txn_begin() and #mdb_txn_renew().
- * @param[in] txn the transaction handle to initialize
- * @return 0 on success, non-zero on failure.
- */
-static int
-mdb_txn_renew0(MDB_txn *txn)
-{
-	MDB_env *env = txn->mt_env;
-	MDB_txninfo *ti = env->me_txns;
-	MDB_meta *meta;
-	unsigned int i, nr, flags = txn->mt_flags;
-	uint16_t x;
-	int rc, new_notls = 0;
-
-	if ((flags &= MDB_TXN_RDONLY) != 0) {
-		if (!ti) {
-			meta = mdb_env_pick_meta(env);
-			txn->mt_txnid = meta->mm_txnid;
-			txn->mt_u.reader = NULL;
-		} else {
-			MDB_reader *r = (env->me_flags & MDB_NOTLS) ? txn->mt_u.reader :
-				pthread_getspecific(env->me_txkey);
-			if (r) {
-				if (r->mr_pid != env->me_pid || r->mr_txnid != (txnid_t)-1)
-					return MDB_BAD_RSLOT;
-			} else {
-				MDB_PID_T pid = env->me_pid;
-				MDB_THR_T tid = pthread_self();
-				mdb_mutexref_t rmutex = env->me_rmutex;
-
-				if (!env->me_live_reader) {
-					rc = mdb_reader_pid(env, Pidset, pid);
-					if (rc)
-						return rc;
-					env->me_live_reader = 1;
-				}
-
-				if (LOCK_MUTEX(rc, env, rmutex))
-					return rc;
-				nr = ti->mti_numreaders;
-				for (i=0; i<nr; i++)
-					if (ti->mti_readers[i].mr_pid == 0)
-						break;
-				if (i == env->me_maxreaders) {
-					UNLOCK_MUTEX(rmutex);
-					return MDB_READERS_FULL;
-				}
-				r = &ti->mti_readers[i];
-				/* Claim the reader slot, carefully since other code
-				 * uses the reader table un-mutexed: First reset the
-				 * slot, next publish it in mti_numreaders.  After
-				 * that, it is safe for mdb_env_close() to touch it.
-				 * When it will be closed, we can finally claim it.
-				 */
-				r->mr_pid = 0;
-				r->mr_txnid = (txnid_t)-1;
-				r->mr_tid = tid;
-				if (i == nr)
-					ti->mti_numreaders = ++nr;
-				env->me_close_readers = nr;
-				r->mr_pid = pid;
-				UNLOCK_MUTEX(rmutex);
-
-				new_notls = (env->me_flags & MDB_NOTLS);
-				if (!new_notls && (rc=pthread_setspecific(env->me_txkey, r))) {
-					r->mr_pid = 0;
-					return rc;
-				}
-			}
-			do /* LY: Retry on a race, ITS#7970. */
-				r->mr_txnid = ti->mti_txnid;
-			while(r->mr_txnid != ti->mti_txnid);
-			txn->mt_txnid = r->mr_txnid;
-			txn->mt_u.reader = r;
-			meta = env->me_metas[txn->mt_txnid & 1];
-		}
-
-	} else {
-		/* Not yet touching txn == env->me_txn0, it may be active */
-		if (ti) {
-			if (LOCK_MUTEX(rc, env, env->me_wmutex))
-				return rc;
-			txn->mt_txnid = ti->mti_txnid;
-			meta = env->me_metas[txn->mt_txnid & 1];
-		} else {
-			meta = mdb_env_pick_meta(env);
-			txn->mt_txnid = meta->mm_txnid;
-		}
-		txn->mt_txnid++;
-#if MDB_DEBUG
-		if (txn->mt_txnid == mdb_debug_start)
-			mdb_debug = 1;
-#endif
-		txn->mt_child = NULL;
-		txn->mt_loose_pgs = NULL;
-		txn->mt_loose_count = 0;
-		txn->mt_dirty_room = MDB_IDL_UM_MAX;
-		txn->mt_u.dirty_list = env->me_dirty_list;
-		txn->mt_u.dirty_list[0].mid = 0;
-		txn->mt_free_pgs = env->me_free_pgs;
-		txn->mt_free_pgs[0] = 0;
-		txn->mt_spill_pgs = NULL;
-		env->me_txn = txn;
-		memcpy(txn->mt_dbiseqs, env->me_dbiseqs, env->me_maxdbs * sizeof(unsigned int));
-	}
-
-	/* Copy the DB info and flags */
-	memcpy(txn->mt_dbs, meta->mm_dbs, CORE_DBS * sizeof(MDB_db));
-
-	/* Moved to here to avoid a data race in read TXNs */
-	txn->mt_next_pgno = meta->mm_last_pg+1;
-#ifdef MDB_VL32
-	txn->mt_last_pgno = txn->mt_next_pgno - 1;
-#endif
-
-	txn->mt_flags = flags;
-
-	/* Setup db info */
-	txn->mt_numdbs = env->me_numdbs;
-	for (i=CORE_DBS; i<txn->mt_numdbs; i++) {
-		x = env->me_dbflags[i];
-		txn->mt_dbs[i].md_flags = x & PERSISTENT_FLAGS;
-		txn->mt_dbflags[i] = (x & MDB_VALID) ? DB_VALID|DB_USRVALID|DB_STALE : 0;
-	}
-	txn->mt_dbflags[MAIN_DBI] = DB_VALID|DB_USRVALID;
-	txn->mt_dbflags[FREE_DBI] = DB_VALID;
-
-	if (env->me_flags & MDB_FATAL_ERROR) {
-		DPUTS("environment had fatal error, must shutdown!");
-		rc = MDB_PANIC;
-	} else if (env->me_maxpg < txn->mt_next_pgno) {
-		rc = MDB_MAP_RESIZED;
-	} else {
-		return MDB_SUCCESS;
-	}
-	mdb_txn_end(txn, new_notls /*0 or MDB_END_SLOT*/ | MDB_END_FAIL_BEGIN);
-	return rc;
-}
-
-int
-mdb_txn_renew(MDB_txn *txn)
-{
-	int rc;
-
-	if (!txn || !F_ISSET(txn->mt_flags, MDB_TXN_RDONLY|MDB_TXN_FINISHED))
-		return EINVAL;
-
-	rc = mdb_txn_renew0(txn);
-	if (rc == MDB_SUCCESS) {
-		DPRINTF(("renew txn %"Y"u%c %p on mdbenv %p, root page %"Y"u",
-			txn->mt_txnid, (txn->mt_flags & MDB_TXN_RDONLY) ? 'r' : 'w',
-			(void *)txn, (void *)txn->mt_env, txn->mt_dbs[MAIN_DBI].md_root));
-	}
-	return rc;
-}
-
-int
-mdb_txn_begin(MDB_env *env, MDB_txn *parent, unsigned int flags, MDB_txn **ret)
-{
-	MDB_txn *txn;
-	MDB_ntxn *ntxn;
-	int rc, size, tsize;
-
-	flags &= MDB_TXN_BEGIN_FLAGS;
-	flags |= env->me_flags & MDB_WRITEMAP;
-
-	if (env->me_flags & MDB_RDONLY & ~flags) /* write txn in RDONLY env */
-		return EACCES;
-
-	if (parent) {
-		/* Nested transactions: Max 1 child, write txns only, no writemap */
-		flags |= parent->mt_flags;
-		if (flags & (MDB_RDONLY|MDB_WRITEMAP|MDB_TXN_BLOCKED)) {
-			return (parent->mt_flags & MDB_TXN_RDONLY) ? EINVAL : MDB_BAD_TXN;
-		}
-		/* Child txns save MDB_pgstate and use own copy of cursors */
-		size = env->me_maxdbs * (sizeof(MDB_db)+sizeof(MDB_cursor *)+1);
-		size += tsize = sizeof(MDB_ntxn);
-	} else if (flags & MDB_RDONLY) {
-		size = env->me_maxdbs * (sizeof(MDB_db)+1);
-		size += tsize = sizeof(MDB_txn);
-	} else {
-		/* Reuse preallocated write txn. However, do not touch it until
-		 * mdb_txn_renew0() succeeds, since it currently may be active.
-		 */
-		txn = env->me_txn0;
-		goto renew;
-	}
-	if ((txn = calloc(1, size)) == NULL) {
-		DPRINTF(("calloc: %s", strerror(errno)));
-		return ENOMEM;
-	}
-#ifdef MDB_VL32
-	if (!parent) {
-		txn->mt_rpages = malloc(MDB_TRPAGE_SIZE * sizeof(MDB_ID3));
-		if (!txn->mt_rpages) {
-			free(txn);
-			return ENOMEM;
-		}
-		txn->mt_rpages[0].mid = 0;
-		txn->mt_rpcheck = MDB_TRPAGE_SIZE/2;
-	}
-#endif
-	txn->mt_dbxs = env->me_dbxs;	/* static */
-	txn->mt_dbs = (MDB_db *) ((char *)txn + tsize);
-	txn->mt_dbflags = (unsigned char *)txn + size - env->me_maxdbs;
-	txn->mt_flags = flags;
-	txn->mt_env = env;
-
-	if (parent) {
-		unsigned int i;
-		txn->mt_cursors = (MDB_cursor **)(txn->mt_dbs + env->me_maxdbs);
-		txn->mt_dbiseqs = parent->mt_dbiseqs;
-		txn->mt_u.dirty_list = malloc(sizeof(MDB_ID2)*MDB_IDL_UM_SIZE);
-		if (!txn->mt_u.dirty_list ||
-			!(txn->mt_free_pgs = mdb_midl_alloc(MDB_IDL_UM_MAX)))
-		{
-			free(txn->mt_u.dirty_list);
-			free(txn);
-			return ENOMEM;
-		}
-		txn->mt_txnid = parent->mt_txnid;
-		txn->mt_dirty_room = parent->mt_dirty_room;
-		txn->mt_u.dirty_list[0].mid = 0;
-		txn->mt_spill_pgs = NULL;
-		txn->mt_next_pgno = parent->mt_next_pgno;
-		parent->mt_flags |= MDB_TXN_HAS_CHILD;
-		parent->mt_child = txn;
-		txn->mt_parent = parent;
-		txn->mt_numdbs = parent->mt_numdbs;
-#ifdef MDB_VL32
-		txn->mt_rpages = parent->mt_rpages;
-#endif
-		memcpy(txn->mt_dbs, parent->mt_dbs, txn->mt_numdbs * sizeof(MDB_db));
-		/* Copy parent's mt_dbflags, but clear DB_NEW */
-		for (i=0; i<txn->mt_numdbs; i++)
-			txn->mt_dbflags[i] = parent->mt_dbflags[i] & ~DB_NEW;
-		rc = 0;
-		ntxn = (MDB_ntxn *)txn;
-		ntxn->mnt_pgstate = env->me_pgstate; /* save parent me_pghead & co */
-		if (env->me_pghead) {
-			size = MDB_IDL_SIZEOF(env->me_pghead);
-			env->me_pghead = mdb_midl_alloc(env->me_pghead[0]);
-			if (env->me_pghead)
-				memcpy(env->me_pghead, ntxn->mnt_pgstate.mf_pghead, size);
-			else
-				rc = ENOMEM;
-		}
-		if (!rc)
-			rc = mdb_cursor_shadow(parent, txn);
-		if (rc)
-			mdb_txn_end(txn, MDB_END_FAIL_BEGINCHILD);
-	} else { /* MDB_RDONLY */
-		txn->mt_dbiseqs = env->me_dbiseqs;
-renew:
-		rc = mdb_txn_renew0(txn);
-	}
-	if (rc) {
-		if (txn != env->me_txn0) {
-#ifdef MDB_VL32
-			free(txn->mt_rpages);
-#endif
-			free(txn);
-		}
-	} else {
-		txn->mt_flags |= flags;	/* could not change txn=me_txn0 earlier */
-		*ret = txn;
-		DPRINTF(("begin txn %"Y"u%c %p on mdbenv %p, root page %"Y"u",
-			txn->mt_txnid, (flags & MDB_RDONLY) ? 'r' : 'w',
-			(void *) txn, (void *) env, txn->mt_dbs[MAIN_DBI].md_root));
-	}
-
-	return rc;
-}
-
-MDB_env *
-mdb_txn_env(MDB_txn *txn)
-{
-	if(!txn) return NULL;
-	return txn->mt_env;
-}
-
-mdb_size_t
-mdb_txn_id(MDB_txn *txn)
-{
-    if(!txn) return 0;
-    return txn->mt_txnid;
-}
-
-/** Export or close DBI handles opened in this txn. */
-static void
-mdb_dbis_update(MDB_txn *txn, int keep)
-{
-	int i;
-	MDB_dbi n = txn->mt_numdbs;
-	MDB_env *env = txn->mt_env;
-	unsigned char *tdbflags = txn->mt_dbflags;
-
-	for (i = n; --i >= CORE_DBS;) {
-		if (tdbflags[i] & DB_NEW) {
-			if (keep) {
-				env->me_dbflags[i] = txn->mt_dbs[i].md_flags | MDB_VALID;
-			} else {
-				char *ptr = env->me_dbxs[i].md_name.mv_data;
-				if (ptr) {
-					env->me_dbxs[i].md_name.mv_data = NULL;
-					env->me_dbxs[i].md_name.mv_size = 0;
-					env->me_dbflags[i] = 0;
-					env->me_dbiseqs[i]++;
-					free(ptr);
-				}
-			}
-		}
-	}
-	if (keep && env->me_numdbs < n)
-		env->me_numdbs = n;
-}
-
-/** End a transaction, except successful commit of a nested transaction.
- * May be called twice for readonly txns: First reset it, then abort.
- * @param[in] txn the transaction handle to end
- * @param[in] mode why and how to end the transaction
- */
-static void
-mdb_txn_end(MDB_txn *txn, unsigned mode)
-{
-	MDB_env	*env = txn->mt_env;
-#if MDB_DEBUG
-	static const char *const names[] = MDB_END_NAMES;
-#endif
-
-	/* Export or close DBI handles opened in this txn */
-	mdb_dbis_update(txn, mode & MDB_END_UPDATE);
-
-	DPRINTF(("%s txn %"Y"u%c %p on mdbenv %p, root page %"Y"u",
-		names[mode & MDB_END_OPMASK],
-		txn->mt_txnid, (txn->mt_flags & MDB_TXN_RDONLY) ? 'r' : 'w',
-		(void *) txn, (void *)env, txn->mt_dbs[MAIN_DBI].md_root));
-
-	if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY)) {
-		if (txn->mt_u.reader) {
-			txn->mt_u.reader->mr_txnid = (txnid_t)-1;
-			if (!(env->me_flags & MDB_NOTLS)) {
-				txn->mt_u.reader = NULL; /* txn does not own reader */
-			} else if (mode & MDB_END_SLOT) {
-				txn->mt_u.reader->mr_pid = 0;
-				txn->mt_u.reader = NULL;
-			} /* else txn owns the slot until it does MDB_END_SLOT */
-		}
-		txn->mt_numdbs = 0;		/* prevent further DBI activity */
-		txn->mt_flags |= MDB_TXN_FINISHED;
-
-	} else if (!F_ISSET(txn->mt_flags, MDB_TXN_FINISHED)) {
-		pgno_t *pghead = env->me_pghead;
-
-		if (!(mode & MDB_END_UPDATE)) /* !(already closed cursors) */
-			mdb_cursors_close(txn, 0);
-		if (!(env->me_flags & MDB_WRITEMAP)) {
-			mdb_dlist_free(txn);
-		}
-
-		txn->mt_numdbs = 0;
-		txn->mt_flags = MDB_TXN_FINISHED;
-
-		if (!txn->mt_parent) {
-			mdb_midl_shrink(&txn->mt_free_pgs);
-			env->me_free_pgs = txn->mt_free_pgs;
-			/* me_pgstate: */
-			env->me_pghead = NULL;
-			env->me_pglast = 0;
-
-			env->me_txn = NULL;
-			mode = 0;	/* txn == env->me_txn0, do not free() it */
-
-			/* The writer mutex was locked in mdb_txn_begin. */
-			if (env->me_txns)
-				UNLOCK_MUTEX(env->me_wmutex);
-		} else {
-			txn->mt_parent->mt_child = NULL;
-			txn->mt_parent->mt_flags &= ~MDB_TXN_HAS_CHILD;
-			env->me_pgstate = ((MDB_ntxn *)txn)->mnt_pgstate;
-			mdb_midl_free(txn->mt_free_pgs);
-			mdb_midl_free(txn->mt_spill_pgs);
-			free(txn->mt_u.dirty_list);
-		}
-
-		mdb_midl_free(pghead);
-	}
-#ifdef MDB_VL32
-	if (!txn->mt_parent) {
-		MDB_ID3L el = env->me_rpages, tl = txn->mt_rpages;
-		unsigned i, x, n = tl[0].mid;
-		pthread_mutex_lock(&env->me_rpmutex);
-		for (i = 1; i <= n; i++) {
-			if (tl[i].mid & (MDB_RPAGE_CHUNK-1)) {
-				/* tmp overflow pages that we didn't share in env */
-				munmap(tl[i].mptr, tl[i].mcnt * env->me_psize);
-			} else {
-				x = mdb_mid3l_search(el, tl[i].mid);
-				if (tl[i].mptr == el[x].mptr) {
-					el[x].mref--;
-				} else {
-					/* another tmp overflow page */
-					munmap(tl[i].mptr, tl[i].mcnt * env->me_psize);
-				}
-			}
-		}
-		pthread_mutex_unlock(&env->me_rpmutex);
-		tl[0].mid = 0;
-		if (mode & MDB_END_FREE)
-			free(tl);
-	}
-#endif
-	if (mode & MDB_END_FREE)
-		free(txn);
-}
-
-void
-mdb_txn_reset(MDB_txn *txn)
-{
-	if (txn == NULL)
-		return;
-
-	/* This call is only valid for read-only txns */
-	if (!(txn->mt_flags & MDB_TXN_RDONLY))
-		return;
-
-	mdb_txn_end(txn, MDB_END_RESET);
-}
-
-void
-mdb_txn_abort(MDB_txn *txn)
-{
-	if (txn == NULL)
-		return;
-
-	if (txn->mt_child)
-		mdb_txn_abort(txn->mt_child);
-
-	mdb_txn_end(txn, MDB_END_ABORT|MDB_END_SLOT|MDB_END_FREE);
-}
-
-/** Save the freelist as of this transaction to the freeDB.
- * This changes the freelist. Keep trying until it stabilizes.
- *
- * When (MDB_DEVEL) & 2, the changes do not affect #mdb_page_alloc(),
- * it then uses the transaction's original snapshot of the freeDB.
- */
-static int
-mdb_freelist_save(MDB_txn *txn)
-{
-	/* env->me_pghead[] can grow and shrink during this call.
-	 * env->me_pglast and txn->mt_free_pgs[] can only grow.
-	 * Page numbers cannot disappear from txn->mt_free_pgs[].
-	 */
-	MDB_cursor mc;
-	MDB_env	*env = txn->mt_env;
-	int rc, maxfree_1pg = env->me_maxfree_1pg, more = 1;
-	txnid_t	pglast = 0, head_id = 0;
-	pgno_t	freecnt = 0, *free_pgs, *mop;
-	ssize_t	head_room = 0, total_room = 0, mop_len, clean_limit;
-
-	mdb_cursor_init(&mc, txn, FREE_DBI, NULL);
-
-	if (env->me_pghead) {
-		/* Make sure first page of freeDB is touched and on freelist */
-		rc = mdb_page_search(&mc, NULL, MDB_PS_FIRST|MDB_PS_MODIFY);
-		if (rc && rc != MDB_NOTFOUND)
-			return rc;
-	}
-
-	if (!env->me_pghead && txn->mt_loose_pgs) {
-		/* Put loose page numbers in mt_free_pgs, since
-		 * we may be unable to return them to me_pghead.
-		 */
-		MDB_page *mp = txn->mt_loose_pgs;
-		if ((rc = mdb_midl_need(&txn->mt_free_pgs, txn->mt_loose_count)) != 0)
-			return rc;
-		for (; mp; mp = NEXT_LOOSE_PAGE(mp))
-			mdb_midl_xappend(txn->mt_free_pgs, mp->mp_pgno);
-		txn->mt_loose_pgs = NULL;
-		txn->mt_loose_count = 0;
-	}
-
-	/* MDB_RESERVE cancels meminit in ovpage malloc (when no WRITEMAP) */
-	clean_limit = (env->me_flags & (MDB_NOMEMINIT|MDB_WRITEMAP))
-		? SSIZE_MAX : maxfree_1pg;
-
-	for (;;) {
-		/* Come back here after each Put() in case freelist changed */
-		MDB_val key, data;
-		pgno_t *pgs;
-		ssize_t j;
-
-		/* If using records from freeDB which we have not yet
-		 * deleted, delete them and any we reserved for me_pghead.
-		 */
-		while (pglast < env->me_pglast) {
-			rc = mdb_cursor_first(&mc, &key, NULL);
-			if (rc)
-				return rc;
-			pglast = head_id = *(txnid_t *)key.mv_data;
-			total_room = head_room = 0;
-			mdb_tassert(txn, pglast <= env->me_pglast);
-			rc = mdb_cursor_del(&mc, 0);
-			if (rc)
-				return rc;
-		}
-
-		/* Save the IDL of pages freed by this txn, to a single record */
-		if (freecnt < txn->mt_free_pgs[0]) {
-			if (!freecnt) {
-				/* Make sure last page of freeDB is touched and on freelist */
-				rc = mdb_page_search(&mc, NULL, MDB_PS_LAST|MDB_PS_MODIFY);
-				if (rc && rc != MDB_NOTFOUND)
-					return rc;
-			}
-			free_pgs = txn->mt_free_pgs;
-			/* Write to last page of freeDB */
-			key.mv_size = sizeof(txn->mt_txnid);
-			key.mv_data = &txn->mt_txnid;
-			do {
-				freecnt = free_pgs[0];
-				data.mv_size = MDB_IDL_SIZEOF(free_pgs);
-				rc = mdb_cursor_put(&mc, &key, &data, MDB_RESERVE);
-				if (rc)
-					return rc;
-				/* Retry if mt_free_pgs[] grew during the Put() */
-				free_pgs = txn->mt_free_pgs;
-			} while (freecnt < free_pgs[0]);
-			mdb_midl_sort(free_pgs);
-			memcpy(data.mv_data, free_pgs, data.mv_size);
-#if (MDB_DEBUG) > 1
-			{
-				unsigned int i = free_pgs[0];
-				DPRINTF(("IDL write txn %"Y"u root %"Y"u num %u",
-					txn->mt_txnid, txn->mt_dbs[FREE_DBI].md_root, i));
-				for (; i; i--)
-					DPRINTF(("IDL %"Y"u", free_pgs[i]));
-			}
-#endif
-			continue;
-		}
-
-		mop = env->me_pghead;
-		mop_len = (mop ? mop[0] : 0) + txn->mt_loose_count;
-
-		/* Reserve records for me_pghead[]. Split it if multi-page,
-		 * to avoid searching freeDB for a page range. Use keys in
-		 * range [1,me_pglast]: Smaller than txnid of oldest reader.
-		 */
-		if (total_room >= mop_len) {
-			if (total_room == mop_len || --more < 0)
-				break;
-		} else if (head_room >= maxfree_1pg && head_id > 1) {
-			/* Keep current record (overflow page), add a new one */
-			head_id--;
-			head_room = 0;
-		}
-		/* (Re)write {key = head_id, IDL length = head_room} */
-		total_room -= head_room;
-		head_room = mop_len - total_room;
-		if (head_room > maxfree_1pg && head_id > 1) {
-			/* Overflow multi-page for part of me_pghead */
-			head_room /= head_id; /* amortize page sizes */
-			head_room += maxfree_1pg - head_room % (maxfree_1pg + 1);
-		} else if (head_room < 0) {
-			/* Rare case, not bothering to delete this record */
-			head_room = 0;
-		}
-		key.mv_size = sizeof(head_id);
-		key.mv_data = &head_id;
-		data.mv_size = (head_room + 1) * sizeof(pgno_t);
-		rc = mdb_cursor_put(&mc, &key, &data, MDB_RESERVE);
-		if (rc)
-			return rc;
-		/* IDL is initially empty, zero out at least the length */
-		pgs = (pgno_t *)data.mv_data;
-		j = head_room > clean_limit ? head_room : 0;
-		do {
-			pgs[j] = 0;
-		} while (--j >= 0);
-		total_room += head_room;
-	}
-
-	/* Return loose page numbers to me_pghead, though usually none are
-	 * left at this point.  The pages themselves remain in dirty_list.
-	 */
-	if (txn->mt_loose_pgs) {
-		MDB_page *mp = txn->mt_loose_pgs;
-		unsigned count = txn->mt_loose_count;
-		MDB_IDL loose;
-		/* Room for loose pages + temp IDL with same */
-		if ((rc = mdb_midl_need(&env->me_pghead, 2*count+1)) != 0)
-			return rc;
-		mop = env->me_pghead;
-		loose = mop + MDB_IDL_ALLOCLEN(mop) - count;
-		for (count = 0; mp; mp = NEXT_LOOSE_PAGE(mp))
-			loose[ ++count ] = mp->mp_pgno;
-		loose[0] = count;
-		mdb_midl_sort(loose);
-		mdb_midl_xmerge(mop, loose);
-		txn->mt_loose_pgs = NULL;
-		txn->mt_loose_count = 0;
-		mop_len = mop[0];
-	}
-
-	/* Fill in the reserved me_pghead records */
-	rc = MDB_SUCCESS;
-	if (mop_len) {
-		MDB_val key, data;
-
-		mop += mop_len;
-		rc = mdb_cursor_first(&mc, &key, &data);
-		for (; !rc; rc = mdb_cursor_next(&mc, &key, &data, MDB_NEXT)) {
-			txnid_t id = *(txnid_t *)key.mv_data;
-			ssize_t	len = (ssize_t)(data.mv_size / sizeof(MDB_ID)) - 1;
-			MDB_ID save;
-
-			mdb_tassert(txn, len >= 0 && id <= env->me_pglast);
-			key.mv_data = &id;
-			if (len > mop_len) {
-				len = mop_len;
-				data.mv_size = (len + 1) * sizeof(MDB_ID);
-			}
-			data.mv_data = mop -= len;
-			save = mop[0];
-			mop[0] = len;
-			rc = mdb_cursor_put(&mc, &key, &data, MDB_CURRENT);
-			mop[0] = save;
-			if (rc || !(mop_len -= len))
-				break;
-		}
-	}
-	return rc;
-}
-
-/** Flush (some) dirty pages to the map, after clearing their dirty flag.
- * @param[in] txn the transaction that's being committed
- * @param[in] keep number of initial pages in dirty_list to keep dirty.
- * @return 0 on success, non-zero on failure.
- */
-static int
-mdb_page_flush(MDB_txn *txn, int keep)
-{
-	MDB_env		*env = txn->mt_env;
-	MDB_ID2L	dl = txn->mt_u.dirty_list;
-	unsigned	psize = env->me_psize, j;
-	int			i, pagecount = dl[0].mid, rc;
-	size_t		size = 0;
-	off_t		pos = 0;
-	pgno_t		pgno = 0;
-	MDB_page	*dp = NULL;
-#ifdef _WIN32
-	OVERLAPPED	ov;
-#else
-	struct iovec iov[MDB_COMMIT_PAGES];
-	ssize_t		wsize = 0, wres;
-	off_t		wpos = 0, next_pos = 1; /* impossible pos, so pos != next_pos */
-	int			n = 0;
-#endif
-
-	j = i = keep;
-
-	if (env->me_flags & MDB_WRITEMAP) {
-		/* Clear dirty flags */
-		while (++i <= pagecount) {
-			dp = dl[i].mptr;
-			/* Don't flush this page yet */
-			if (dp->mp_flags & (P_LOOSE|P_KEEP)) {
-				dp->mp_flags &= ~P_KEEP;
-				dl[++j] = dl[i];
-				continue;
-			}
-			dp->mp_flags &= ~P_DIRTY;
-		}
-		goto done;
-	}
-
-	/* Write the pages */
-	for (;;) {
-		if (++i <= pagecount) {
-			dp = dl[i].mptr;
-			/* Don't flush this page yet */
-			if (dp->mp_flags & (P_LOOSE|P_KEEP)) {
-				dp->mp_flags &= ~P_KEEP;
-				dl[i].mid = 0;
-				continue;
-			}
-			pgno = dl[i].mid;
-			/* clear dirty flag */
-			dp->mp_flags &= ~P_DIRTY;
-			pos = pgno * psize;
-			size = psize;
-			if (IS_OVERFLOW(dp)) size *= dp->mp_pages;
-		}
-#ifdef _WIN32
-		else break;
-
-		/* Windows actually supports scatter/gather I/O, but only on
-		 * unbuffered file handles. Since we're relying on the OS page
-		 * cache for all our data, that's self-defeating. So we just
-		 * write pages one at a time. We use the ov structure to set
-		 * the write offset, to at least save the overhead of a Seek
-		 * system call.
-		 */
-		DPRINTF(("committing page %"Z"u", pgno));
-		memset(&ov, 0, sizeof(ov));
-		ov.Offset = pos & 0xffffffff;
-		ov.OffsetHigh = pos >> 16 >> 16;
-		if (!WriteFile(env->me_fd, dp, size, NULL, &ov)) {
-			rc = ErrCode();
-			DPRINTF(("WriteFile: %d", rc));
-			return rc;
-		}
-#else
-		/* Write up to MDB_COMMIT_PAGES dirty pages at a time. */
-		if (pos!=next_pos || n==MDB_COMMIT_PAGES || wsize+size>MAX_WRITE) {
-			if (n) {
-retry_write:
-				/* Write previous page(s) */
-#ifdef MDB_USE_PWRITEV
-				wres = pwritev(env->me_fd, iov, n, wpos);
-#else
-				if (n == 1) {
-					wres = pwrite(env->me_fd, iov[0].iov_base, wsize, wpos);
-				} else {
-retry_seek:
-					if (lseek(env->me_fd, wpos, SEEK_SET) == -1) {
-						rc = ErrCode();
-						if (rc == EINTR)
-							goto retry_seek;
-						DPRINTF(("lseek: %s", strerror(rc)));
-						return rc;
-					}
-					wres = writev(env->me_fd, iov, n);
-				}
-#endif
-				if (wres != wsize) {
-					if (wres < 0) {
-						rc = ErrCode();
-						if (rc == EINTR)
-							goto retry_write;
-						DPRINTF(("Write error: %s", strerror(rc)));
-					} else {
-						rc = EIO; /* TODO: Use which error code? */
-						DPUTS("short write, filesystem full?");
-					}
-					return rc;
-				}
-				n = 0;
-			}
-			if (i > pagecount)
-				break;
-			wpos = pos;
-			wsize = 0;
-		}
-		DPRINTF(("committing page %"Y"u", pgno));
-		next_pos = pos + size;
-		iov[n].iov_len = size;
-		iov[n].iov_base = (char *)dp;
-		wsize += size;
-		n++;
-#endif	/* _WIN32 */
-	}
-#ifdef MDB_VL32
-	if (pgno > txn->mt_last_pgno)
-		txn->mt_last_pgno = pgno;
-#endif
-
-	/* MIPS has cache coherency issues, this is a no-op everywhere else
-	 * Note: for any size >= on-chip cache size, entire on-chip cache is
-	 * flushed.
-	 */
-	CACHEFLUSH(env->me_map, txn->mt_next_pgno * env->me_psize, DCACHE);
-
-	for (i = keep; ++i <= pagecount; ) {
-		dp = dl[i].mptr;
-		/* This is a page we skipped above */
-		if (!dl[i].mid) {
-			dl[++j] = dl[i];
-			dl[j].mid = dp->mp_pgno;
-			continue;
-		}
-		mdb_dpage_free(env, dp);
-	}
-
-done:
-	i--;
-	txn->mt_dirty_room += i - j;
-	dl[0].mid = j;
-	return MDB_SUCCESS;
-}
-
-int
-mdb_txn_commit(MDB_txn *txn)
-{
-	int		rc;
-	unsigned int i, end_mode;
-	MDB_env	*env;
-
-	if (txn == NULL)
-		return EINVAL;
-
-	/* mdb_txn_end() mode for a commit which writes nothing */
-	end_mode = MDB_END_EMPTY_COMMIT|MDB_END_UPDATE|MDB_END_SLOT|MDB_END_FREE;
-
-	if (txn->mt_child) {
-		rc = mdb_txn_commit(txn->mt_child);
-		if (rc)
-			goto fail;
-	}
-
-	env = txn->mt_env;
-
-	if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY)) {
-		goto done;
-	}
-
-	if (txn->mt_flags & (MDB_TXN_FINISHED|MDB_TXN_ERROR)) {
-		DPUTS("txn has failed/finished, can't commit");
-		if (txn->mt_parent)
-			txn->mt_parent->mt_flags |= MDB_TXN_ERROR;
-		rc = MDB_BAD_TXN;
-		goto fail;
-	}
-
-	if (txn->mt_parent) {
-		MDB_txn *parent = txn->mt_parent;
-		MDB_page **lp;
-		MDB_ID2L dst, src;
-		MDB_IDL pspill;
-		unsigned x, y, len, ps_len;
-
-		/* Append our free list to parent's */
-		rc = mdb_midl_append_list(&parent->mt_free_pgs, txn->mt_free_pgs);
-		if (rc)
-			goto fail;
-		mdb_midl_free(txn->mt_free_pgs);
-		/* Failures after this must either undo the changes
-		 * to the parent or set MDB_TXN_ERROR in the parent.
-		 */
-
-		parent->mt_next_pgno = txn->mt_next_pgno;
-		parent->mt_flags = txn->mt_flags;
-
-		/* Merge our cursors into parent's and close them */
-		mdb_cursors_close(txn, 1);
-
-		/* Update parent's DB table. */
-		memcpy(parent->mt_dbs, txn->mt_dbs, txn->mt_numdbs * sizeof(MDB_db));
-		parent->mt_numdbs = txn->mt_numdbs;
-		parent->mt_dbflags[FREE_DBI] = txn->mt_dbflags[FREE_DBI];
-		parent->mt_dbflags[MAIN_DBI] = txn->mt_dbflags[MAIN_DBI];
-		for (i=CORE_DBS; i<txn->mt_numdbs; i++) {
-			/* preserve parent's DB_NEW status */
-			x = parent->mt_dbflags[i] & DB_NEW;
-			parent->mt_dbflags[i] = txn->mt_dbflags[i] | x;
-		}
-
-		dst = parent->mt_u.dirty_list;
-		src = txn->mt_u.dirty_list;
-		/* Remove anything in our dirty list from parent's spill list */
-		if ((pspill = parent->mt_spill_pgs) && (ps_len = pspill[0])) {
-			x = y = ps_len;
-			pspill[0] = (pgno_t)-1;
-			/* Mark our dirty pages as deleted in parent spill list */
-			for (i=0, len=src[0].mid; ++i <= len; ) {
-				MDB_ID pn = src[i].mid << 1;
-				while (pn > pspill[x])
-					x--;
-				if (pn == pspill[x]) {
-					pspill[x] = 1;
-					y = --x;
-				}
-			}
-			/* Squash deleted pagenums if we deleted any */
-			for (x=y; ++x <= ps_len; )
-				if (!(pspill[x] & 1))
-					pspill[++y] = pspill[x];
-			pspill[0] = y;
-		}
-
-		/* Remove anything in our spill list from parent's dirty list */
-		if (txn->mt_spill_pgs && txn->mt_spill_pgs[0]) {
-			for (i=1; i<=txn->mt_spill_pgs[0]; i++) {
-				MDB_ID pn = txn->mt_spill_pgs[i];
-				if (pn & 1)
-					continue;	/* deleted spillpg */
-				pn >>= 1;
-				y = mdb_mid2l_search(dst, pn);
-				if (y <= dst[0].mid && dst[y].mid == pn) {
-					free(dst[y].mptr);
-					while (y < dst[0].mid) {
-						dst[y] = dst[y+1];
-						y++;
-					}
-					dst[0].mid--;
-				}
-			}
-		}
-
-		/* Find len = length of merging our dirty list with parent's */
-		x = dst[0].mid;
-		dst[0].mid = 0;		/* simplify loops */
-		if (parent->mt_parent) {
-			len = x + src[0].mid;
-			y = mdb_mid2l_search(src, dst[x].mid + 1) - 1;
-			for (i = x; y && i; y--) {
-				pgno_t yp = src[y].mid;
-				while (yp < dst[i].mid)
-					i--;
-				if (yp == dst[i].mid) {
-					i--;
-					len--;
-				}
-			}
-		} else { /* Simplify the above for single-ancestor case */
-			len = MDB_IDL_UM_MAX - txn->mt_dirty_room;
-		}
-		/* Merge our dirty list with parent's */
-		y = src[0].mid;
-		for (i = len; y; dst[i--] = src[y--]) {
-			pgno_t yp = src[y].mid;
-			while (yp < dst[x].mid)
-				dst[i--] = dst[x--];
-			if (yp == dst[x].mid)
-				free(dst[x--].mptr);
-		}
-		mdb_tassert(txn, i == x);
-		dst[0].mid = len;
-		free(txn->mt_u.dirty_list);
-		parent->mt_dirty_room = txn->mt_dirty_room;
-		if (txn->mt_spill_pgs) {
-			if (parent->mt_spill_pgs) {
-				/* TODO: Prevent failure here, so parent does not fail */
-				rc = mdb_midl_append_list(&parent->mt_spill_pgs, txn->mt_spill_pgs);
-				if (rc)
-					parent->mt_flags |= MDB_TXN_ERROR;
-				mdb_midl_free(txn->mt_spill_pgs);
-				mdb_midl_sort(parent->mt_spill_pgs);
-			} else {
-				parent->mt_spill_pgs = txn->mt_spill_pgs;
-			}
-		}
-
-		/* Append our loose page list to parent's */
-		for (lp = &parent->mt_loose_pgs; *lp; lp = &NEXT_LOOSE_PAGE(*lp))
-			;
-		*lp = txn->mt_loose_pgs;
-		parent->mt_loose_count += txn->mt_loose_count;
-
-		parent->mt_child = NULL;
-		mdb_midl_free(((MDB_ntxn *)txn)->mnt_pgstate.mf_pghead);
-		free(txn);
-		return rc;
-	}
-
-	if (txn != env->me_txn) {
-		DPUTS("attempt to commit unknown transaction");
-		rc = EINVAL;
-		goto fail;
-	}
-
-	mdb_cursors_close(txn, 0);
-
-	if (!txn->mt_u.dirty_list[0].mid &&
-		!(txn->mt_flags & (MDB_TXN_DIRTY|MDB_TXN_SPILLS)))
-		goto done;
-
-	DPRINTF(("committing txn %"Y"u %p on mdbenv %p, root page %"Y"u",
-	    txn->mt_txnid, (void*)txn, (void*)env, txn->mt_dbs[MAIN_DBI].md_root));
-
-	/* Update DB root pointers */
-	if (txn->mt_numdbs > CORE_DBS) {
-		MDB_cursor mc;
-		MDB_dbi i;
-		MDB_val data;
-		data.mv_size = sizeof(MDB_db);
-
-		mdb_cursor_init(&mc, txn, MAIN_DBI, NULL);
-		for (i = CORE_DBS; i < txn->mt_numdbs; i++) {
-			if (txn->mt_dbflags[i] & DB_DIRTY) {
-				if (TXN_DBI_CHANGED(txn, i)) {
-					rc = MDB_BAD_DBI;
-					goto fail;
-				}
-				data.mv_data = &txn->mt_dbs[i];
-				rc = mdb_cursor_put(&mc, &txn->mt_dbxs[i].md_name, &data,
-					F_SUBDATA);
-				if (rc)
-					goto fail;
-			}
-		}
-	}
-
-	rc = mdb_freelist_save(txn);
-	if (rc)
-		goto fail;
-
-	mdb_midl_free(env->me_pghead);
-	env->me_pghead = NULL;
-	mdb_midl_shrink(&txn->mt_free_pgs);
-
-#if (MDB_DEBUG) > 2
-	mdb_audit(txn);
-#endif
-
-	if ((rc = mdb_page_flush(txn, 0)))
-		goto fail;
-	if (!F_ISSET(txn->mt_flags, MDB_TXN_NOSYNC) &&
-		(rc = mdb_env_sync0(env, 0, txn->mt_next_pgno)))
-		goto fail;
-	if ((rc = mdb_env_write_meta(txn)))
-		goto fail;
-	end_mode = MDB_END_COMMITTED|MDB_END_UPDATE;
-
-done:
-	mdb_txn_end(txn, end_mode);
-	return MDB_SUCCESS;
-
-fail:
-	mdb_txn_abort(txn);
-	return rc;
-}
-
-/** Read the environment parameters of a DB environment before
- * mapping it into memory.
- * @param[in] env the environment handle
- * @param[out] meta address of where to store the meta information
- * @return 0 on success, non-zero on failure.
- */
-static int ESECT
-mdb_env_read_header(MDB_env *env, MDB_meta *meta)
-{
-	MDB_metabuf	pbuf;
-	MDB_page	*p;
-	MDB_meta	*m;
-	int			i, rc, off;
-	enum { Size = sizeof(pbuf) };
-
-	/* We don't know the page size yet, so use a minimum value.
-	 * Read both meta pages so we can use the latest one.
-	 */
-
-	for (i=off=0; i<NUM_METAS; i++, off += meta->mm_psize) {
-#ifdef _WIN32
-		DWORD len;
-		OVERLAPPED ov;
-		memset(&ov, 0, sizeof(ov));
-		ov.Offset = off;
-		rc = ReadFile(env->me_fd, &pbuf, Size, &len, &ov) ? (int)len : -1;
-		if (rc == -1 && ErrCode() == ERROR_HANDLE_EOF)
-			rc = 0;
-#else
-		rc = pread(env->me_fd, &pbuf, Size, off);
-#endif
-		if (rc != Size) {
-			if (rc == 0 && off == 0)
-				return ENOENT;
-			rc = rc < 0 ? (int) ErrCode() : MDB_INVALID;
-			DPRINTF(("read: %s", mdb_strerror(rc)));
-			return rc;
-		}
-
-		p = (MDB_page *)&pbuf;
-
-		if (!F_ISSET(p->mp_flags, P_META)) {
-			DPRINTF(("page %"Y"u not a meta page", p->mp_pgno));
-			return MDB_INVALID;
-		}
-
-		m = METADATA(p);
-		if (m->mm_magic != MDB_MAGIC) {
-			DPUTS("meta has invalid magic");
-			return MDB_INVALID;
-		}
-
-		if (m->mm_version != MDB_DATA_VERSION) {
-			DPRINTF(("database is version %u, expected version %u",
-				m->mm_version, MDB_DATA_VERSION));
-			return MDB_VERSION_MISMATCH;
-		}
-
-		if (off == 0 || m->mm_txnid > meta->mm_txnid)
-			*meta = *m;
-	}
-	return 0;
-}
-
-/** Fill in most of the zeroed #MDB_meta for an empty database environment */
-static void ESECT
-mdb_env_init_meta0(MDB_env *env, MDB_meta *meta)
-{
-	meta->mm_magic = MDB_MAGIC;
-	meta->mm_version = MDB_DATA_VERSION;
-	meta->mm_mapsize = env->me_mapsize;
-	meta->mm_psize = env->me_psize;
-	meta->mm_last_pg = NUM_METAS-1;
-	meta->mm_flags = env->me_flags & 0xffff;
-	meta->mm_flags |= MDB_INTEGERKEY; /* this is mm_dbs[FREE_DBI].md_flags */
-	meta->mm_dbs[FREE_DBI].md_root = P_INVALID;
-	meta->mm_dbs[MAIN_DBI].md_root = P_INVALID;
-}
-
-/** Write the environment parameters of a freshly created DB environment.
- * @param[in] env the environment handle
- * @param[in] meta the #MDB_meta to write
- * @return 0 on success, non-zero on failure.
- */
-static int ESECT
-mdb_env_init_meta(MDB_env *env, MDB_meta *meta)
-{
-	MDB_page *p, *q;
-	int rc;
-	unsigned int	 psize;
-#ifdef _WIN32
-	DWORD len;
-	OVERLAPPED ov;
-	memset(&ov, 0, sizeof(ov));
-#define DO_PWRITE(rc, fd, ptr, size, len, pos)	do { \
-	ov.Offset = pos;	\
-	rc = WriteFile(fd, ptr, size, &len, &ov);	} while(0)
-#else
-	int len;
-#define DO_PWRITE(rc, fd, ptr, size, len, pos)	do { \
-	len = pwrite(fd, ptr, size, pos);	\
-	if (len == -1 && ErrCode() == EINTR) continue; \
-	rc = (len >= 0); break; } while(1)
-#endif
-
-	DPUTS("writing new meta page");
-
-	psize = env->me_psize;
-
-	p = calloc(NUM_METAS, psize);
-	if (!p)
-		return ENOMEM;
-	p->mp_pgno = 0;
-	p->mp_flags = P_META;
-	*(MDB_meta *)METADATA(p) = *meta;
-
-	q = (MDB_page *)((char *)p + psize);
-	q->mp_pgno = 1;
-	q->mp_flags = P_META;
-	*(MDB_meta *)METADATA(q) = *meta;
-
-	DO_PWRITE(rc, env->me_fd, p, psize * NUM_METAS, len, 0);
-	if (!rc)
-		rc = ErrCode();
-	else if ((unsigned) len == psize * NUM_METAS)
-		rc = MDB_SUCCESS;
-	else
-		rc = ENOSPC;
-	free(p);
-	return rc;
-}
-
-/** Update the environment info to commit a transaction.
- * @param[in] txn the transaction that's being committed
- * @return 0 on success, non-zero on failure.
- */
-static int
-mdb_env_write_meta(MDB_txn *txn)
-{
-	MDB_env *env;
-	MDB_meta	meta, metab, *mp;
-	unsigned flags;
-	mdb_size_t mapsize;
-	off_t off;
-	int rc, len, toggle;
-	char *ptr;
-	HANDLE mfd;
-#ifdef _WIN32
-	OVERLAPPED ov;
-#else
-	int r2;
-#endif
-
-	toggle = txn->mt_txnid & 1;
-	DPRINTF(("writing meta page %d for root page %"Y"u",
-		toggle, txn->mt_dbs[MAIN_DBI].md_root));
-
-	env = txn->mt_env;
-	flags = txn->mt_flags | env->me_flags;
-	mp = env->me_metas[toggle];
-	mapsize = env->me_metas[toggle ^ 1]->mm_mapsize;
-	/* Persist any increases of mapsize config */
-	if (mapsize < env->me_mapsize)
-		mapsize = env->me_mapsize;
-
-	if (flags & MDB_WRITEMAP) {
-		mp->mm_mapsize = mapsize;
-		mp->mm_dbs[FREE_DBI] = txn->mt_dbs[FREE_DBI];
-		mp->mm_dbs[MAIN_DBI] = txn->mt_dbs[MAIN_DBI];
-		mp->mm_last_pg = txn->mt_next_pgno - 1;
-#if (__GNUC__ * 100 + __GNUC_MINOR__ >= 404) && /* TODO: portability */	\
-	!(defined(__i386__) || defined(__x86_64__))
-		/* LY: issue a memory barrier, if not x86. ITS#7969 */
-		__sync_synchronize();
-#endif
-		mp->mm_txnid = txn->mt_txnid;
-		if (!(flags & (MDB_NOMETASYNC|MDB_NOSYNC))) {
-			unsigned meta_size = env->me_psize;
-			rc = (env->me_flags & MDB_MAPASYNC) ? MS_ASYNC : MS_SYNC;
-			ptr = (char *)mp - PAGEHDRSZ;
-#ifndef _WIN32	/* POSIX msync() requires ptr = start of OS page */
-			r2 = (ptr - env->me_map) & (env->me_os_psize - 1);
-			ptr -= r2;
-			meta_size += r2;
-#endif
-			if (MDB_MSYNC(ptr, meta_size, rc)) {
-				rc = ErrCode();
-				goto fail;
-			}
-		}
-		goto done;
-	}
-	metab.mm_txnid = mp->mm_txnid;
-	metab.mm_last_pg = mp->mm_last_pg;
-
-	meta.mm_mapsize = mapsize;
-	meta.mm_dbs[FREE_DBI] = txn->mt_dbs[FREE_DBI];
-	meta.mm_dbs[MAIN_DBI] = txn->mt_dbs[MAIN_DBI];
-	meta.mm_last_pg = txn->mt_next_pgno - 1;
-	meta.mm_txnid = txn->mt_txnid;
-
-	off = offsetof(MDB_meta, mm_mapsize);
-	ptr = (char *)&meta + off;
-	len = sizeof(MDB_meta) - off;
-	off += (char *)mp - env->me_map;
-
-	/* Write to the SYNC fd */
-	mfd = (flags & (MDB_NOSYNC|MDB_NOMETASYNC)) ? env->me_fd : env->me_mfd;
-#ifdef _WIN32
-	{
-		memset(&ov, 0, sizeof(ov));
-		ov.Offset = off;
-		if (!WriteFile(mfd, ptr, len, (DWORD *)&rc, &ov))
-			rc = -1;
-	}
-#else
-retry_write:
-	rc = pwrite(mfd, ptr, len, off);
-#endif
-	if (rc != len) {
-		rc = rc < 0 ? ErrCode() : EIO;
-#ifndef _WIN32
-		if (rc == EINTR)
-			goto retry_write;
-#endif
-		DPUTS("write failed, disk error?");
-		/* On a failure, the pagecache still contains the new data.
-		 * Write some old data back, to prevent it from being used.
-		 * Use the non-SYNC fd; we know it will fail anyway.
-		 */
-		meta.mm_last_pg = metab.mm_last_pg;
-		meta.mm_txnid = metab.mm_txnid;
-#ifdef _WIN32
-		memset(&ov, 0, sizeof(ov));
-		ov.Offset = off;
-		WriteFile(env->me_fd, ptr, len, NULL, &ov);
-#else
-		r2 = pwrite(env->me_fd, ptr, len, off);
-		(void)r2;	/* Silence warnings. We don't care about pwrite's return value */
-#endif
-fail:
-		env->me_flags |= MDB_FATAL_ERROR;
-		return rc;
-	}
-	/* MIPS has cache coherency issues, this is a no-op everywhere else */
-	CACHEFLUSH(env->me_map + off, len, DCACHE);
-done:
-	/* Memory ordering issues are irrelevant; since the entire writer
-	 * is wrapped by wmutex, all of these changes will become visible
-	 * after the wmutex is unlocked. Since the DB is multi-version,
-	 * readers will get consistent data regardless of how fresh or
-	 * how stale their view of these values is.
-	 */
-	if (env->me_txns)
-		env->me_txns->mti_txnid = txn->mt_txnid;
-
-	return MDB_SUCCESS;
-}
-
-/** Check both meta pages to see which one is newer.
- * @param[in] env the environment handle
- * @return newest #MDB_meta.
- */
-static MDB_meta *
-mdb_env_pick_meta(const MDB_env *env)
-{
-	MDB_meta *const *metas = env->me_metas;
-	return metas[ metas[0]->mm_txnid < metas[1]->mm_txnid ];
-}
-
-int ESECT
-mdb_env_create(MDB_env **env)
-{
-	MDB_env *e;
-
-	e = calloc(1, sizeof(MDB_env));
-	if (!e)
-		return ENOMEM;
-
-	e->me_maxreaders = DEFAULT_READERS;
-	e->me_maxdbs = e->me_numdbs = CORE_DBS;
-	e->me_fd = INVALID_HANDLE_VALUE;
-	e->me_lfd = INVALID_HANDLE_VALUE;
-	e->me_mfd = INVALID_HANDLE_VALUE;
-#ifdef MDB_USE_POSIX_SEM
-	e->me_rmutex = SEM_FAILED;
-	e->me_wmutex = SEM_FAILED;
-#elif defined MDB_USE_SYSV_SEM
-	e->me_rmutex->semid = -1;
-	e->me_wmutex->semid = -1;
-#endif
-	e->me_pid = getpid();
-	GET_PAGESIZE(e->me_os_psize);
-	VGMEMP_CREATE(e,0,0);
-	*env = e;
-	return MDB_SUCCESS;
-}
-
-#ifdef _WIN32
-/** @brief Map a result from an NTAPI call to WIN32. */
-static DWORD
-mdb_nt2win32(NTSTATUS st)
-{
-	OVERLAPPED o = {0};
-	DWORD br;
-	o.Internal = st;
-	GetOverlappedResult(NULL, &o, &br, FALSE);
-	return GetLastError();
-}
-#endif
-
-static int ESECT
-mdb_env_map(MDB_env *env, void *addr)
-{
-	MDB_page *p;
-	unsigned int flags = env->me_flags;
-#ifdef _WIN32
-	int rc;
-	int access = SECTION_MAP_READ;
-	HANDLE mh;
-	void *map;
-	SIZE_T msize;
-	ULONG pageprot = PAGE_READONLY, secprot, alloctype;
-
-	if (flags & MDB_WRITEMAP) {
-		access |= SECTION_MAP_WRITE;
-		pageprot = PAGE_READWRITE;
-	}
-	if (flags & MDB_RDONLY) {
-		secprot = PAGE_READONLY;
-		msize = 0;
-		alloctype = 0;
-	} else {
-		secprot = PAGE_READWRITE;
-		msize = env->me_mapsize;
-		alloctype = MEM_RESERVE;
-	}
-
-	rc = NtCreateSection(&mh, access, NULL, NULL, secprot, SEC_RESERVE, env->me_fd);
-	if (rc)
-		return mdb_nt2win32(rc);
-	map = addr;
-#ifdef MDB_VL32
-	msize = NUM_METAS * env->me_psize;
-#endif
-	rc = NtMapViewOfSection(mh, GetCurrentProcess(), &map, 0, 0, NULL, &msize, ViewUnmap, alloctype, pageprot);
-#ifdef MDB_VL32
-	env->me_fmh = mh;
-#else
-	NtClose(mh);
-#endif
-	if (rc)
-		return mdb_nt2win32(rc);
-	env->me_map = map;
-#else
-#ifdef MDB_VL32
-	(void) flags;
-	env->me_map = mmap(addr, NUM_METAS * env->me_psize, PROT_READ, MAP_SHARED,
-		env->me_fd, 0);
-	if (env->me_map == MAP_FAILED) {
-		env->me_map = NULL;
-		return ErrCode();
-	}
-#else
-	int prot = PROT_READ;
-	if (flags & MDB_WRITEMAP) {
-		prot |= PROT_WRITE;
-		if (ftruncate(env->me_fd, env->me_mapsize) < 0)
-			return ErrCode();
-	}
-	env->me_map = mmap(addr, env->me_mapsize, prot, MAP_SHARED,
-		env->me_fd, 0);
-	if (env->me_map == MAP_FAILED) {
-		env->me_map = NULL;
-		return ErrCode();
-	}
-
-	if (flags & MDB_NORDAHEAD) {
-		/* Turn off readahead. It's harmful when the DB is larger than RAM. */
-#ifdef MADV_RANDOM
-		madvise(env->me_map, env->me_mapsize, MADV_RANDOM);
-#else
-#ifdef POSIX_MADV_RANDOM
-		posix_madvise(env->me_map, env->me_mapsize, POSIX_MADV_RANDOM);
-#endif /* POSIX_MADV_RANDOM */
-#endif /* MADV_RANDOM */
-	}
-#endif /* _WIN32 */
-
-	/* Can happen because the address argument to mmap() is just a
-	 * hint.  mmap() can pick another, e.g. if the range is in use.
-	 * The MAP_FIXED flag would prevent that, but then mmap could
-	 * instead unmap existing pages to make room for the new map.
-	 */
-	if (addr && env->me_map != addr)
-		return EBUSY;	/* TODO: Make a new MDB_* error code? */
-#endif
-
-	p = (MDB_page *)env->me_map;
-	env->me_metas[0] = METADATA(p);
-	env->me_metas[1] = (MDB_meta *)((char *)env->me_metas[0] + env->me_psize);
-
-	return MDB_SUCCESS;
-}
-
-int ESECT
-mdb_env_set_mapsize(MDB_env *env, mdb_size_t size)
-{
-	/* If env is already open, caller is responsible for making
-	 * sure there are no active txns.
-	 */
-	if (env->me_map) {
-		MDB_meta *meta;
-#ifndef MDB_VL32
-		void *old;
-		int rc;
-#endif
-		if (env->me_txn)
-			return EINVAL;
-		meta = mdb_env_pick_meta(env);
-		if (!size)
-			size = meta->mm_mapsize;
-		{
-			/* Silently round up to minimum if the size is too small */
-			mdb_size_t minsize = (meta->mm_last_pg + 1) * env->me_psize;
-			if (size < minsize)
-				size = minsize;
-		}
-#ifndef MDB_VL32
-		/* For MDB_VL32 this bit is a noop since we dynamically remap
-		 * chunks of the DB anyway.
-		 */
-		munmap(env->me_map, env->me_mapsize);
-		env->me_mapsize = size;
-		old = (env->me_flags & MDB_FIXEDMAP) ? env->me_map : NULL;
-		rc = mdb_env_map(env, old);
-		if (rc)
-			return rc;
-#endif /* !MDB_VL32 */
-	}
-	env->me_mapsize = size;
-	if (env->me_psize)
-		env->me_maxpg = env->me_mapsize / env->me_psize;
-	return MDB_SUCCESS;
-}
-
-int ESECT
-mdb_env_set_maxdbs(MDB_env *env, MDB_dbi dbs)
-{
-	if (env->me_map)
-		return EINVAL;
-	env->me_maxdbs = dbs + CORE_DBS;
-	return MDB_SUCCESS;
-}
-
-int ESECT
-mdb_env_set_maxreaders(MDB_env *env, unsigned int readers)
-{
-	if (env->me_map || readers < 1)
-		return EINVAL;
-	env->me_maxreaders = readers;
-	return MDB_SUCCESS;
-}
-
-int ESECT
-mdb_env_get_maxreaders(MDB_env *env, unsigned int *readers)
-{
-	if (!env || !readers)
-		return EINVAL;
-	*readers = env->me_maxreaders;
-	return MDB_SUCCESS;
-}
-
-static int ESECT
-mdb_fsize(HANDLE fd, mdb_size_t *size)
-{
-#ifdef _WIN32
-	LARGE_INTEGER fsize;
-
-	if (!GetFileSizeEx(fd, &fsize))
-		return ErrCode();
-
-	*size = fsize.QuadPart;
-#else
-	struct stat st;
-
-	if (fstat(fd, &st))
-		return ErrCode();
-
-	*size = st.st_size;
-#endif
-	return MDB_SUCCESS;
-}
-
-#ifdef BROKEN_FDATASYNC
-#include <sys/utsname.h>
-#include <sys/vfs.h>
-#endif
-
-/** Further setup required for opening an LMDB environment
- */
-static int ESECT
-mdb_env_open2(MDB_env *env)
-{
-	unsigned int flags = env->me_flags;
-	int i, newenv = 0, rc;
-	MDB_meta meta;
-
-#ifdef _WIN32
-	/* See if we should use QueryLimited */
-	rc = GetVersion();
-	if ((rc & 0xff) > 5)
-		env->me_pidquery = MDB_PROCESS_QUERY_LIMITED_INFORMATION;
-	else
-		env->me_pidquery = PROCESS_QUERY_INFORMATION;
-#endif /* _WIN32 */
-
-#ifdef BROKEN_FDATASYNC
-	/* ext3/ext4 fdatasync is broken on some older Linux kernels.
-	 * https://lkml.org/lkml/2012/9/3/83
-	 * Kernels after 3.6-rc6 are known good.
-	 * https://lkml.org/lkml/2012/9/10/556
-	 * See if the DB is on ext3/ext4, then check for new enough kernel
-	 * Kernels 2.6.32.60, 2.6.34.15, 3.2.30, and 3.5.4 are also known
-	 * to be patched.
-	 */
-	{
-		struct statfs st;
-		fstatfs(env->me_fd, &st);
-		while (st.f_type == 0xEF53) {
-			struct utsname uts;
-			int i;
-			uname(&uts);
-			if (uts.release[0] < '3') {
-				if (!strncmp(uts.release, "2.6.32.", 7)) {
-					i = atoi(uts.release+7);
-					if (i >= 60)
-						break;	/* 2.6.32.60 and newer is OK */
-				} else if (!strncmp(uts.release, "2.6.34.", 7)) {
-					i = atoi(uts.release+7);
-					if (i >= 15)
-						break;	/* 2.6.34.15 and newer is OK */
-				}
-			} else if (uts.release[0] == '3') {
-				i = atoi(uts.release+2);
-				if (i > 5)
-					break;	/* 3.6 and newer is OK */
-				if (i == 5) {
-					i = atoi(uts.release+4);
-					if (i >= 4)
-						break;	/* 3.5.4 and newer is OK */
-				} else if (i == 2) {
-					i = atoi(uts.release+4);
-					if (i >= 30)
-						break;	/* 3.2.30 and newer is OK */
-				}
-			} else {	/* 4.x and newer is OK */
-				break;
-			}
-			env->me_flags |= MDB_FSYNCONLY;
-			break;
-		}
-	}
-#endif
-
-	if ((i = mdb_env_read_header(env, &meta)) != 0) {
-		if (i != ENOENT)
-			return i;
-		DPUTS("new mdbenv");
-		newenv = 1;
-		env->me_psize = env->me_os_psize;
-		if (env->me_psize > MAX_PAGESIZE)
-			env->me_psize = MAX_PAGESIZE;
-		memset(&meta, 0, sizeof(meta));
-		mdb_env_init_meta0(env, &meta);
-		meta.mm_mapsize = DEFAULT_MAPSIZE;
-	} else {
-		env->me_psize = meta.mm_psize;
-	}
-
-	/* Was a mapsize configured? */
-	if (!env->me_mapsize) {
-		env->me_mapsize = meta.mm_mapsize;
-	}
-	{
-		/* Make sure mapsize >= committed data size.  Even when using
-		 * mm_mapsize, which could be broken in old files (ITS#7789).
-		 */
-		mdb_size_t minsize = (meta.mm_last_pg + 1) * meta.mm_psize;
-		if (env->me_mapsize < minsize)
-			env->me_mapsize = minsize;
-	}
-	meta.mm_mapsize = env->me_mapsize;
-
-	if (newenv && !(flags & MDB_FIXEDMAP)) {
-		/* mdb_env_map() may grow the datafile.  Write the metapages
-		 * first, so the file will be valid if initialization fails.
-		 * Except with FIXEDMAP, since we do not yet know mm_address.
-		 * We could fill in mm_address later, but then a different
-		 * program might end up doing that - one with a memory layout
-		 * and map address which does not suit the main program.
-		 */
-		rc = mdb_env_init_meta(env, &meta);
-		if (rc)
-			return rc;
-		newenv = 0;
-	}
-#ifdef _WIN32
-	/* For FIXEDMAP, make sure the file is non-empty before we attempt to map it */
-	if (newenv) {
-		char dummy = 0;
-		DWORD len;
-		rc = WriteFile(env->me_fd, &dummy, 1, &len, NULL);
-		if (!rc) {
-			rc = ErrCode();
-			return rc;
-		}
-	}
-#endif
-
-	rc = mdb_env_map(env, (flags & MDB_FIXEDMAP) ? meta.mm_address : NULL);
-	if (rc)
-		return rc;
-
-	if (newenv) {
-		if (flags & MDB_FIXEDMAP)
-			meta.mm_address = env->me_map;
-		i = mdb_env_init_meta(env, &meta);
-		if (i != MDB_SUCCESS) {
-			return i;
-		}
-	}
-
-	env->me_maxfree_1pg = (env->me_psize - PAGEHDRSZ) / sizeof(pgno_t) - 1;
-	env->me_nodemax = (((env->me_psize - PAGEHDRSZ) / MDB_MINKEYS) & -2)
-		- sizeof(indx_t);
-#if !(MDB_MAXKEYSIZE)
-	env->me_maxkey = env->me_nodemax - (NODESIZE + sizeof(MDB_db));
-#endif
-	env->me_maxpg = env->me_mapsize / env->me_psize;
-
-#if MDB_DEBUG
-	{
-		MDB_meta *meta = mdb_env_pick_meta(env);
-		MDB_db *db = &meta->mm_dbs[MAIN_DBI];
-
-		DPRINTF(("opened database version %u, pagesize %u",
-			meta->mm_version, env->me_psize));
-		DPRINTF(("using meta page %d",    (int) (meta->mm_txnid & 1)));
-		DPRINTF(("depth: %u",             db->md_depth));
-		DPRINTF(("entries: %"Y"u",        db->md_entries));
-		DPRINTF(("branch pages: %"Y"u",   db->md_branch_pages));
-		DPRINTF(("leaf pages: %"Y"u",     db->md_leaf_pages));
-		DPRINTF(("overflow pages: %"Y"u", db->md_overflow_pages));
-		DPRINTF(("root: %"Y"u",           db->md_root));
-	}
-#endif
-
-	return MDB_SUCCESS;
-}
-
-
-/** Release a reader thread's slot in the reader lock table.
- *	This function is called automatically when a thread exits.
- * @param[in] ptr This points to the slot in the reader lock table.
- */
-static void
-mdb_env_reader_dest(void *ptr)
-{
-	MDB_reader *reader = ptr;
-
-	reader->mr_pid = 0;
-}
-
-#ifdef _WIN32
-/** Junk for arranging thread-specific callbacks on Windows. This is
- *	necessarily platform and compiler-specific. Windows supports up
- *	to 1088 keys. Let's assume nobody opens more than 64 environments
- *	in a single process, for now. They can override this if needed.
- */
-#ifndef MAX_TLS_KEYS
-#define MAX_TLS_KEYS	64
-#endif
-static pthread_key_t mdb_tls_keys[MAX_TLS_KEYS];
-static int mdb_tls_nkeys;
-
-static void NTAPI mdb_tls_callback(PVOID module, DWORD reason, PVOID ptr)
-{
-	int i;
-	switch(reason) {
-	case DLL_PROCESS_ATTACH: break;
-	case DLL_THREAD_ATTACH: break;
-	case DLL_THREAD_DETACH:
-		for (i=0; i<mdb_tls_nkeys; i++) {
-			MDB_reader *r = pthread_getspecific(mdb_tls_keys[i]);
-			if (r) {
-				mdb_env_reader_dest(r);
-			}
-		}
-		break;
-	case DLL_PROCESS_DETACH: break;
-	}
-}
-#ifdef __GNUC__
-#ifdef _WIN64
-const PIMAGE_TLS_CALLBACK mdb_tls_cbp __attribute__((section (".CRT$XLB"))) = mdb_tls_callback;
-#else
-PIMAGE_TLS_CALLBACK mdb_tls_cbp __attribute__((section (".CRT$XLB"))) = mdb_tls_callback;
-#endif
-#else
-#ifdef _WIN64
-/* Force some symbol references.
- *	_tls_used forces the linker to create the TLS directory if not already done
- *	mdb_tls_cbp prevents whole-program-optimizer from dropping the symbol.
- */
-#pragma comment(linker, "/INCLUDE:_tls_used")
-#pragma comment(linker, "/INCLUDE:mdb_tls_cbp")
-#pragma const_seg(".CRT$XLB")
-extern const PIMAGE_TLS_CALLBACK mdb_tls_cbp;
-const PIMAGE_TLS_CALLBACK mdb_tls_cbp = mdb_tls_callback;
-#pragma const_seg()
-#else	/* _WIN32 */
-#pragma comment(linker, "/INCLUDE:__tls_used")
-#pragma comment(linker, "/INCLUDE:_mdb_tls_cbp")
-#pragma data_seg(".CRT$XLB")
-PIMAGE_TLS_CALLBACK mdb_tls_cbp = mdb_tls_callback;
-#pragma data_seg()
-#endif	/* WIN 32/64 */
-#endif	/* !__GNUC__ */
-#endif
-
-/** Downgrade the exclusive lock on the region back to shared */
-static int ESECT
-mdb_env_share_locks(MDB_env *env, int *excl)
-{
-	int rc = 0;
-	MDB_meta *meta = mdb_env_pick_meta(env);
-
-	env->me_txns->mti_txnid = meta->mm_txnid;
-
-#ifdef _WIN32
-	{
-		OVERLAPPED ov;
-		/* First acquire a shared lock. The Unlock will
-		 * then release the existing exclusive lock.
-		 */
-		memset(&ov, 0, sizeof(ov));
-		if (!LockFileEx(env->me_lfd, 0, 0, 1, 0, &ov)) {
-			rc = ErrCode();
-		} else {
-			UnlockFile(env->me_lfd, 0, 0, 1, 0);
-			*excl = 0;
-		}
-	}
-#else
-	{
-		struct flock lock_info;
-		/* The shared lock replaces the existing lock */
-		memset((void *)&lock_info, 0, sizeof(lock_info));
-		lock_info.l_type = F_RDLCK;
-		lock_info.l_whence = SEEK_SET;
-		lock_info.l_start = 0;
-		lock_info.l_len = 1;
-		while ((rc = fcntl(env->me_lfd, F_SETLK, &lock_info)) &&
-				(rc = ErrCode()) == EINTR) ;
-		*excl = rc ? -1 : 0;	/* error may mean we lost the lock */
-	}
-#endif
-
-	return rc;
-}
-
-/** Try to get exclusive lock, otherwise shared.
- *	Maintain *excl = -1: no/unknown lock, 0: shared, 1: exclusive.
- */
-static int ESECT
-mdb_env_excl_lock(MDB_env *env, int *excl)
-{
-	int rc = 0;
-#ifdef _WIN32
-	if (LockFile(env->me_lfd, 0, 0, 1, 0)) {
-		*excl = 1;
-	} else {
-		OVERLAPPED ov;
-		memset(&ov, 0, sizeof(ov));
-		if (LockFileEx(env->me_lfd, 0, 0, 1, 0, &ov)) {
-			*excl = 0;
-		} else {
-			rc = ErrCode();
-		}
-	}
-#else
-	struct flock lock_info;
-	memset((void *)&lock_info, 0, sizeof(lock_info));
-	lock_info.l_type = F_WRLCK;
-	lock_info.l_whence = SEEK_SET;
-	lock_info.l_start = 0;
-	lock_info.l_len = 1;
-	while ((rc = fcntl(env->me_lfd, F_SETLK, &lock_info)) &&
-			(rc = ErrCode()) == EINTR) ;
-	if (!rc) {
-		*excl = 1;
-	} else
-# ifndef MDB_USE_POSIX_MUTEX
-	if (*excl < 0) /* always true when MDB_USE_POSIX_MUTEX */
-# endif
-	{
-		lock_info.l_type = F_RDLCK;
-		while ((rc = fcntl(env->me_lfd, F_SETLKW, &lock_info)) &&
-				(rc = ErrCode()) == EINTR) ;
-		if (rc == 0)
-			*excl = 0;
-	}
-#endif
-	return rc;
-}
-
-#ifdef MDB_USE_HASH
-/*
- * hash_64 - 64 bit Fowler/Noll/Vo-0 FNV-1a hash code
- *
- * @(#) $Revision: 5.1 $
- * @(#) $Id: hash_64a.c,v 5.1 2009/06/30 09:01:38 chongo Exp $
- * @(#) $Source: /usr/local/src/cmd/fnv/RCS/hash_64a.c,v $
- *
- *	  http://www.isthe.com/chongo/tech/comp/fnv/index.html
- *
- ***
- *
- * Please do not copyright this code.  This code is in the public domain.
- *
- * LANDON CURT NOLL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
- * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO
- * EVENT SHALL LANDON CURT NOLL BE LIABLE FOR ANY SPECIAL, INDIRECT OR
- * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
- * USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
- * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
- * PERFORMANCE OF THIS SOFTWARE.
- *
- * By:
- *	chongo <Landon Curt Noll> /\oo/\
- *	  http://www.isthe.com/chongo/
- *
- * Share and Enjoy!	:-)
- */
-
-typedef unsigned long long	mdb_hash_t;
-#define MDB_HASH_INIT ((mdb_hash_t)0xcbf29ce484222325ULL)
-
-/** perform a 64 bit Fowler/Noll/Vo FNV-1a hash on a buffer
- * @param[in] val	value to hash
- * @param[in] hval	initial value for hash
- * @return 64 bit hash
- *
- * NOTE: To use the recommended 64 bit FNV-1a hash, use MDB_HASH_INIT as the
- * 	 hval arg on the first call.
- */
-static mdb_hash_t
-mdb_hash_val(MDB_val *val, mdb_hash_t hval)
-{
-	unsigned char *s = (unsigned char *)val->mv_data;	/* unsigned string */
-	unsigned char *end = s + val->mv_size;
-	/*
-	 * FNV-1a hash each octet of the string
-	 */
-	while (s < end) {
-		/* xor the bottom with the current octet */
-		hval ^= (mdb_hash_t)*s++;
-
-		/* multiply by the 64 bit FNV magic prime mod 2^64 */
-		hval += (hval << 1) + (hval << 4) + (hval << 5) +
-			(hval << 7) + (hval << 8) + (hval << 40);
-	}
-	/* return our new hash value */
-	return hval;
-}
-
-/** Hash the string and output the encoded hash.
- * This uses modified RFC1924 Ascii85 encoding to accommodate systems with
- * very short name limits. We don't care about the encoding being reversible,
- * we just want to preserve as many bits of the input as possible in a
- * small printable string.
- * @param[in] str string to hash
- * @param[out] encbuf an array of 11 chars to hold the hash
- */
-static const char mdb_a85[]= "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz!#$%&()*+-;<=>?@^_`{|}~";
-
-static void ESECT
-mdb_pack85(unsigned long l, char *out)
-{
-	int i;
-
-	for (i=0; i<5; i++) {
-		*out++ = mdb_a85[l % 85];
-		l /= 85;
-	}
-}
-
-static void ESECT
-mdb_hash_enc(MDB_val *val, char *encbuf)
-{
-	mdb_hash_t h = mdb_hash_val(val, MDB_HASH_INIT);
-
-	mdb_pack85(h, encbuf);
-	mdb_pack85(h>>32, encbuf+5);
-	encbuf[10] = '\0';
-}
-#endif
-
-/** Open and/or initialize the lock region for the environment.
- * @param[in] env The LMDB environment.
- * @param[in] lpath The pathname of the file used for the lock region.
- * @param[in] mode The Unix permissions for the file, if we create it.
- * @param[in,out] excl In -1, out lock type: -1 none, 0 shared, 1 exclusive
- * @return 0 on success, non-zero on failure.
- */
-static int ESECT
-mdb_env_setup_locks(MDB_env *env, char *lpath, int mode, int *excl)
-{
-#ifdef _WIN32
-#	define MDB_ERRCODE_ROFS	ERROR_WRITE_PROTECT
-#else
-#	define MDB_ERRCODE_ROFS	EROFS
-#ifdef O_CLOEXEC	/* Linux: Open file and set FD_CLOEXEC atomically */
-#	define MDB_CLOEXEC		O_CLOEXEC
-#else
-	int fdflags;
-#	define MDB_CLOEXEC		0
-#endif
-#endif
-#ifdef MDB_USE_SYSV_SEM
-	int semid;
-	union semun semu;
-#endif
-	int rc;
-	off_t size, rsize;
-
-#ifdef _WIN32
-	wchar_t *wlpath;
-	rc = utf8_to_utf16(lpath, -1, &wlpath, NULL);
-	if (rc)
-		return rc;
-	env->me_lfd = CreateFileW(wlpath, GENERIC_READ|GENERIC_WRITE,
-		FILE_SHARE_READ|FILE_SHARE_WRITE, NULL, OPEN_ALWAYS,
-		FILE_ATTRIBUTE_NORMAL, NULL);
-	free(wlpath);
-#else
-	env->me_lfd = open(lpath, O_RDWR|O_CREAT|MDB_CLOEXEC, mode);
-#endif
-	if (env->me_lfd == INVALID_HANDLE_VALUE) {
-		rc = ErrCode();
-		if (rc == MDB_ERRCODE_ROFS && (env->me_flags & MDB_RDONLY)) {
-			return MDB_SUCCESS;
-		}
-		goto fail_errno;
-	}
-#if ! ((MDB_CLOEXEC) || defined(_WIN32))
-	/* Lose record locks when exec*() */
-	if ((fdflags = fcntl(env->me_lfd, F_GETFD) | FD_CLOEXEC) >= 0)
-			fcntl(env->me_lfd, F_SETFD, fdflags);
-#endif
-
-	if (!(env->me_flags & MDB_NOTLS)) {
-		rc = pthread_key_create(&env->me_txkey, mdb_env_reader_dest);
-		if (rc)
-			goto fail;
-		env->me_flags |= MDB_ENV_TXKEY;
-#ifdef _WIN32
-		/* Windows TLS callbacks need help finding their TLS info. */
-		if (mdb_tls_nkeys >= MAX_TLS_KEYS) {
-			rc = MDB_TLS_FULL;
-			goto fail;
-		}
-		mdb_tls_keys[mdb_tls_nkeys++] = env->me_txkey;
-#endif
-	}
-
-	/* Try to get exclusive lock. If we succeed, then
-	 * nobody is using the lock region and we should initialize it.
-	 */
-	if ((rc = mdb_env_excl_lock(env, excl))) goto fail;
-
-#ifdef _WIN32
-	size = GetFileSize(env->me_lfd, NULL);
-#else
-	size = lseek(env->me_lfd, 0, SEEK_END);
-	if (size == -1) goto fail_errno;
-#endif
-	rsize = (env->me_maxreaders-1) * sizeof(MDB_reader) + sizeof(MDB_txninfo);
-	if (size < rsize && *excl > 0) {
-#ifdef _WIN32
-		if (SetFilePointer(env->me_lfd, rsize, NULL, FILE_BEGIN) != (DWORD)rsize
-			|| !SetEndOfFile(env->me_lfd))
-			goto fail_errno;
-#else
-		if (ftruncate(env->me_lfd, rsize) != 0) goto fail_errno;
-#endif
-	} else {
-		rsize = size;
-		size = rsize - sizeof(MDB_txninfo);
-		env->me_maxreaders = size/sizeof(MDB_reader) + 1;
-	}
-	{
-#ifdef _WIN32
-		HANDLE mh;
-		mh = CreateFileMapping(env->me_lfd, NULL, PAGE_READWRITE,
-			0, 0, NULL);
-		if (!mh) goto fail_errno;
-		env->me_txns = MapViewOfFileEx(mh, FILE_MAP_WRITE, 0, 0, rsize, NULL);
-		CloseHandle(mh);
-		if (!env->me_txns) goto fail_errno;
-#else
-		void *m = mmap(NULL, rsize, PROT_READ|PROT_WRITE, MAP_SHARED,
-			env->me_lfd, 0);
-		if (m == MAP_FAILED) goto fail_errno;
-		env->me_txns = m;
-#endif
-	}
-	if (*excl > 0) {
-#ifdef _WIN32
-		BY_HANDLE_FILE_INFORMATION stbuf;
-		struct {
-			DWORD volume;
-			DWORD nhigh;
-			DWORD nlow;
-		} idbuf;
-		MDB_val val;
-		char encbuf[11];
-
-		if (!mdb_sec_inited) {
-			InitializeSecurityDescriptor(&mdb_null_sd,
-				SECURITY_DESCRIPTOR_REVISION);
-			SetSecurityDescriptorDacl(&mdb_null_sd, TRUE, 0, FALSE);
-			mdb_all_sa.nLength = sizeof(SECURITY_ATTRIBUTES);
-			mdb_all_sa.bInheritHandle = FALSE;
-			mdb_all_sa.lpSecurityDescriptor = &mdb_null_sd;
-			mdb_sec_inited = 1;
-		}
-		if (!GetFileInformationByHandle(env->me_lfd, &stbuf)) goto fail_errno;
-		idbuf.volume = stbuf.dwVolumeSerialNumber;
-		idbuf.nhigh  = stbuf.nFileIndexHigh;
-		idbuf.nlow   = stbuf.nFileIndexLow;
-		val.mv_data = &idbuf;
-		val.mv_size = sizeof(idbuf);
-		mdb_hash_enc(&val, encbuf);
-		sprintf(env->me_txns->mti_rmname, "Global\\MDBr%s", encbuf);
-		sprintf(env->me_txns->mti_wmname, "Global\\MDBw%s", encbuf);
-		env->me_rmutex = CreateMutexA(&mdb_all_sa, FALSE, env->me_txns->mti_rmname);
-		if (!env->me_rmutex) goto fail_errno;
-		env->me_wmutex = CreateMutexA(&mdb_all_sa, FALSE, env->me_txns->mti_wmname);
-		if (!env->me_wmutex) goto fail_errno;
-#elif defined(MDB_USE_POSIX_SEM)
-		struct stat stbuf;
-		struct {
-			dev_t dev;
-			ino_t ino;
-		} idbuf;
-		MDB_val val;
-		char encbuf[11];
-
-#if defined(__NetBSD__)
-#define	MDB_SHORT_SEMNAMES	1	/* limited to 14 chars */
-#endif
-		if (fstat(env->me_lfd, &stbuf)) goto fail_errno;
-		idbuf.dev = stbuf.st_dev;
-		idbuf.ino = stbuf.st_ino;
-		val.mv_data = &idbuf;
-		val.mv_size = sizeof(idbuf);
-		mdb_hash_enc(&val, encbuf);
-#ifdef MDB_SHORT_SEMNAMES
-		encbuf[9] = '\0';	/* drop name from 15 chars to 14 chars */
-#endif
-		sprintf(env->me_txns->mti_rmname, "/MDBr%s", encbuf);
-		sprintf(env->me_txns->mti_wmname, "/MDBw%s", encbuf);
-		/* Clean up after a previous run, if needed:  Try to
-		 * remove both semaphores before doing anything else.
-		 */
-		sem_unlink(env->me_txns->mti_rmname);
-		sem_unlink(env->me_txns->mti_wmname);
-		env->me_rmutex = sem_open(env->me_txns->mti_rmname,
-			O_CREAT|O_EXCL, mode, 1);
-		if (env->me_rmutex == SEM_FAILED) goto fail_errno;
-		env->me_wmutex = sem_open(env->me_txns->mti_wmname,
-			O_CREAT|O_EXCL, mode, 1);
-		if (env->me_wmutex == SEM_FAILED) goto fail_errno;
-#elif defined(MDB_USE_SYSV_SEM)
-		unsigned short vals[2] = {1, 1};
-		key_t key = ftok(lpath, 'M');
-		if (key == -1)
-			goto fail_errno;
-		semid = semget(key, 2, (mode & 0777) | IPC_CREAT);
-		if (semid < 0)
-			goto fail_errno;
-		semu.array = vals;
-		if (semctl(semid, 0, SETALL, semu) < 0)
-			goto fail_errno;
-		env->me_txns->mti_semid = semid;
-#else	/* MDB_USE_POSIX_MUTEX: */
-		pthread_mutexattr_t mattr;
-
-		if ((rc = pthread_mutexattr_init(&mattr))
-			|| (rc = pthread_mutexattr_setpshared(&mattr, PTHREAD_PROCESS_SHARED))
-#ifdef MDB_ROBUST_SUPPORTED
-			|| (rc = pthread_mutexattr_setrobust(&mattr, PTHREAD_MUTEX_ROBUST))
-#endif
-			|| (rc = pthread_mutex_init(env->me_txns->mti_rmutex, &mattr))
-			|| (rc = pthread_mutex_init(env->me_txns->mti_wmutex, &mattr)))
-			goto fail;
-		pthread_mutexattr_destroy(&mattr);
-#endif	/* _WIN32 || ... */
-
-		env->me_txns->mti_magic = MDB_MAGIC;
-		env->me_txns->mti_format = MDB_LOCK_FORMAT;
-		env->me_txns->mti_txnid = 0;
-		env->me_txns->mti_numreaders = 0;
-
-	} else {
-#ifdef MDB_USE_SYSV_SEM
-		struct semid_ds buf;
-#endif
-		if (env->me_txns->mti_magic != MDB_MAGIC) {
-			DPUTS("lock region has invalid magic");
-			rc = MDB_INVALID;
-			goto fail;
-		}
-		if (env->me_txns->mti_format != MDB_LOCK_FORMAT) {
-			DPRINTF(("lock region has format+version 0x%x, expected 0x%x",
-				env->me_txns->mti_format, MDB_LOCK_FORMAT));
-			rc = MDB_VERSION_MISMATCH;
-			goto fail;
-		}
-		rc = ErrCode();
-		if (rc && rc != EACCES && rc != EAGAIN) {
-			goto fail;
-		}
-#ifdef _WIN32
-		env->me_rmutex = OpenMutexA(SYNCHRONIZE, FALSE, env->me_txns->mti_rmname);
-		if (!env->me_rmutex) goto fail_errno;
-		env->me_wmutex = OpenMutexA(SYNCHRONIZE, FALSE, env->me_txns->mti_wmname);
-		if (!env->me_wmutex) goto fail_errno;
-#elif defined(MDB_USE_POSIX_SEM)
-		env->me_rmutex = sem_open(env->me_txns->mti_rmname, 0);
-		if (env->me_rmutex == SEM_FAILED) goto fail_errno;
-		env->me_wmutex = sem_open(env->me_txns->mti_wmname, 0);
-		if (env->me_wmutex == SEM_FAILED) goto fail_errno;
-#elif defined(MDB_USE_SYSV_SEM)
-		semid = env->me_txns->mti_semid;
-		semu.buf = &buf;
-		/* check for read access */
-		if (semctl(semid, 0, IPC_STAT, semu) < 0)
-			goto fail_errno;
-		/* check for write access */
-		if (semctl(semid, 0, IPC_SET, semu) < 0)
-			goto fail_errno;
-#endif
-	}
-#ifdef MDB_USE_SYSV_SEM
-	env->me_rmutex->semid = semid;
-	env->me_wmutex->semid = semid;
-	env->me_rmutex->semnum = 0;
-	env->me_wmutex->semnum = 1;
-	env->me_rmutex->locked = &env->me_txns->mti_rlocked;
-	env->me_wmutex->locked = &env->me_txns->mti_wlocked;
-#endif
-#ifdef MDB_VL32
-#ifdef _WIN32
-	env->me_rpmutex = CreateMutex(NULL, FALSE, NULL);
-#else
-	pthread_mutex_init(&env->me_rpmutex, NULL);
-#endif
-#endif
-
-	return MDB_SUCCESS;
-
-fail_errno:
-	rc = ErrCode();
-fail:
-	return rc;
-}
-
-	/** The name of the lock file in the DB environment */
-#define LOCKNAME	"/lock.mdb"
-	/** The name of the data file in the DB environment */
-#define DATANAME	"/data.mdb"
-	/** The suffix of the lock file when no subdir is used */
-#define LOCKSUFF	"-lock"
-	/** Only a subset of the @ref mdb_env flags can be changed
-	 *	at runtime. Changing other flags requires closing the
-	 *	environment and re-opening it with the new flags.
-	 */
-#define	CHANGEABLE	(MDB_NOSYNC|MDB_NOMETASYNC|MDB_MAPASYNC|MDB_NOMEMINIT)
-#define	CHANGELESS	(MDB_FIXEDMAP|MDB_NOSUBDIR|MDB_RDONLY| \
-	MDB_WRITEMAP|MDB_NOTLS|MDB_NOLOCK|MDB_NORDAHEAD)
-
-#if VALID_FLAGS & PERSISTENT_FLAGS & (CHANGEABLE|CHANGELESS)
-# error "Persistent DB flags & env flags overlap, but both go in mm_flags"
-#endif
-
-int ESECT
-mdb_env_open(MDB_env *env, const char *path, unsigned int flags, mdb_mode_t mode)
-{
-	int		oflags, rc, len, excl = -1;
-	char *lpath, *dpath;
-#ifdef _WIN32
-	wchar_t *wpath;
-#endif
-
-	if (env->me_fd!=INVALID_HANDLE_VALUE || (flags & ~(CHANGEABLE|CHANGELESS)))
-		return EINVAL;
-
-#ifdef MDB_VL32
-	if (flags & MDB_WRITEMAP) {
-		/* silently ignore WRITEMAP in 32 bit mode */
-		flags ^= MDB_WRITEMAP;
-	}
-	if (flags & MDB_FIXEDMAP) {
-		/* cannot support FIXEDMAP */
-		return EINVAL;
-	}
-#endif
-
-	len = strlen(path);
-	if (flags & MDB_NOSUBDIR) {
-		rc = len + sizeof(LOCKSUFF) + len + 1;
-	} else {
-		rc = len + sizeof(LOCKNAME) + len + sizeof(DATANAME);
-	}
-	lpath = malloc(rc);
-	if (!lpath)
-		return ENOMEM;
-	if (flags & MDB_NOSUBDIR) {
-		dpath = lpath + len + sizeof(LOCKSUFF);
-		sprintf(lpath, "%s" LOCKSUFF, path);
-		strcpy(dpath, path);
-	} else {
-		dpath = lpath + len + sizeof(LOCKNAME);
-		sprintf(lpath, "%s" LOCKNAME, path);
-		sprintf(dpath, "%s" DATANAME, path);
-	}
-
-	rc = MDB_SUCCESS;
-	flags |= env->me_flags;
-	if (flags & MDB_RDONLY) {
-		/* silently ignore WRITEMAP when we're only getting read access */
-		flags &= ~MDB_WRITEMAP;
-	} else {
-		if (!((env->me_free_pgs = mdb_midl_alloc(MDB_IDL_UM_MAX)) &&
-			  (env->me_dirty_list = calloc(MDB_IDL_UM_SIZE, sizeof(MDB_ID2)))))
-			rc = ENOMEM;
-	}
-#ifdef MDB_VL32
-	if (!rc) {
-		env->me_rpages = malloc(MDB_ERPAGE_SIZE * sizeof(MDB_ID3));
-		if (!env->me_rpages) {
-			rc = ENOMEM;
-			goto leave;
-		}
-		env->me_rpages[0].mid = 0;
-		env->me_rpcheck = MDB_ERPAGE_SIZE/2;
-	}
-#endif
-	env->me_flags = flags |= MDB_ENV_ACTIVE;
-	if (rc)
-		goto leave;
-
-	env->me_path = strdup(path);
-	env->me_dbxs = calloc(env->me_maxdbs, sizeof(MDB_dbx));
-	env->me_dbflags = calloc(env->me_maxdbs, sizeof(uint16_t));
-	env->me_dbiseqs = calloc(env->me_maxdbs, sizeof(unsigned int));
-	if (!(env->me_dbxs && env->me_path && env->me_dbflags && env->me_dbiseqs)) {
-		rc = ENOMEM;
-		goto leave;
-	}
-	env->me_dbxs[FREE_DBI].md_cmp = mdb_cmp_long; /* aligned MDB_INTEGERKEY */
-
-	/* For RDONLY, get lockfile after we know datafile exists */
-	if (!(flags & (MDB_RDONLY|MDB_NOLOCK))) {
-		rc = mdb_env_setup_locks(env, lpath, mode, &excl);
-		if (rc)
-			goto leave;
-	}
-
-#ifdef _WIN32
-	if (F_ISSET(flags, MDB_RDONLY)) {
-		oflags = GENERIC_READ;
-		len = OPEN_EXISTING;
-	} else {
-		oflags = GENERIC_READ|GENERIC_WRITE;
-		len = OPEN_ALWAYS;
-	}
-	mode = FILE_ATTRIBUTE_NORMAL;
-	rc = utf8_to_utf16(dpath, -1, &wpath, NULL);
-	if (rc)
-		goto leave;
-	env->me_fd = CreateFileW(wpath, oflags, FILE_SHARE_READ|FILE_SHARE_WRITE,
-		NULL, len, mode, NULL);
-	free(wpath);
-#else
-	if (F_ISSET(flags, MDB_RDONLY))
-		oflags = O_RDONLY;
-	else
-		oflags = O_RDWR | O_CREAT;
-
-	env->me_fd = open(dpath, oflags, mode);
-#endif
-	if (env->me_fd == INVALID_HANDLE_VALUE) {
-		rc = ErrCode();
-		goto leave;
-	}
-
-	if ((flags & (MDB_RDONLY|MDB_NOLOCK)) == MDB_RDONLY) {
-		rc = mdb_env_setup_locks(env, lpath, mode, &excl);
-		if (rc)
-			goto leave;
-	}
-
-	if ((rc = mdb_env_open2(env)) == MDB_SUCCESS) {
-		if (flags & (MDB_RDONLY|MDB_WRITEMAP)) {
-			env->me_mfd = env->me_fd;
-		} else {
-			/* Synchronous fd for meta writes. Needed even with
-			 * MDB_NOSYNC/MDB_NOMETASYNC, in case these get reset.
-			 */
-#ifdef _WIN32
-			len = OPEN_EXISTING;
-			rc = utf8_to_utf16(dpath, -1, &wpath, NULL);
-			if (rc)
-				goto leave;
-			env->me_mfd = CreateFileW(wpath, oflags,
-				FILE_SHARE_READ|FILE_SHARE_WRITE, NULL, len,
-				mode | FILE_FLAG_WRITE_THROUGH, NULL);
-			free(wpath);
-#else
-			oflags &= ~O_CREAT;
-			env->me_mfd = open(dpath, oflags | MDB_DSYNC, mode);
-#endif
-			if (env->me_mfd == INVALID_HANDLE_VALUE) {
-				rc = ErrCode();
-				goto leave;
-			}
-		}
-		DPRINTF(("opened dbenv %p", (void *) env));
-		if (excl > 0) {
-			rc = mdb_env_share_locks(env, &excl);
-			if (rc)
-				goto leave;
-		}
-		if (!(flags & MDB_RDONLY)) {
-			MDB_txn *txn;
-			int tsize = sizeof(MDB_txn), size = tsize + env->me_maxdbs *
-				(sizeof(MDB_db)+sizeof(MDB_cursor *)+sizeof(unsigned int)+1);
-			if ((env->me_pbuf = calloc(1, env->me_psize)) &&
-				(txn = calloc(1, size)))
-			{
-				txn->mt_dbs = (MDB_db *)((char *)txn + tsize);
-				txn->mt_cursors = (MDB_cursor **)(txn->mt_dbs + env->me_maxdbs);
-				txn->mt_dbiseqs = (unsigned int *)(txn->mt_cursors + env->me_maxdbs);
-				txn->mt_dbflags = (unsigned char *)(txn->mt_dbiseqs + env->me_maxdbs);
-				txn->mt_env = env;
-#ifdef MDB_VL32
-				txn->mt_rpages = malloc(MDB_TRPAGE_SIZE * sizeof(MDB_ID3));
-				if (!txn->mt_rpages) {
-					free(txn);
-					rc = ENOMEM;
-					goto leave;
-				}
-				txn->mt_rpages[0].mid = 0;
-				txn->mt_rpcheck = MDB_TRPAGE_SIZE/2;
-#endif
-				txn->mt_dbxs = env->me_dbxs;
-				txn->mt_flags = MDB_TXN_FINISHED;
-				env->me_txn0 = txn;
-			} else {
-				rc = ENOMEM;
-			}
-		}
-	}
-
-leave:
-	if (rc) {
-		mdb_env_close0(env, excl);
-	}
-	free(lpath);
-	return rc;
-}
-
-/** Destroy resources from mdb_env_open(), clear our readers & DBIs */
-static void ESECT
-mdb_env_close0(MDB_env *env, int excl)
-{
-	int i;
-
-	if (!(env->me_flags & MDB_ENV_ACTIVE))
-		return;
-
-	/* Doing this here since me_dbxs may not exist during mdb_env_close */
-	if (env->me_dbxs) {
-		for (i = env->me_maxdbs; --i >= CORE_DBS; )
-			free(env->me_dbxs[i].md_name.mv_data);
-		free(env->me_dbxs);
-	}
-
-	free(env->me_pbuf);
-	free(env->me_dbiseqs);
-	free(env->me_dbflags);
-	free(env->me_path);
-	free(env->me_dirty_list);
-#ifdef MDB_VL32
-	if (env->me_txn0 && env->me_txn0->mt_rpages)
-		free(env->me_txn0->mt_rpages);
-	{ unsigned int x;
-		for (x=1; x<=env->me_rpages[0].mid; x++)
-		munmap(env->me_rpages[x].mptr, env->me_rpages[x].mcnt * env->me_psize);
-	}
-	free(env->me_rpages);
-#endif
-	free(env->me_txn0);
-	mdb_midl_free(env->me_free_pgs);
-
-	if (env->me_flags & MDB_ENV_TXKEY) {
-		pthread_key_delete(env->me_txkey);
-#ifdef _WIN32
-		/* Delete our key from the global list */
-		for (i=0; i<mdb_tls_nkeys; i++)
-			if (mdb_tls_keys[i] == env->me_txkey) {
-				mdb_tls_keys[i] = mdb_tls_keys[mdb_tls_nkeys-1];
-				mdb_tls_nkeys--;
-				break;
-			}
-#endif
-	}
-
-	if (env->me_map) {
-#ifdef MDB_VL32
-		munmap(env->me_map, NUM_METAS*env->me_psize);
-#else
-		munmap(env->me_map, env->me_mapsize);
-#endif
-	}
-	if (env->me_mfd != env->me_fd && env->me_mfd != INVALID_HANDLE_VALUE)
-		(void) close(env->me_mfd);
-	if (env->me_fd != INVALID_HANDLE_VALUE)
-		(void) close(env->me_fd);
-	if (env->me_txns) {
-		MDB_PID_T pid = env->me_pid;
-		/* Clearing readers is done in this function because
-		 * me_txkey with its destructor must be disabled first.
-		 *
-		 * We skip the the reader mutex, so we touch only
-		 * data owned by this process (me_close_readers and
-		 * our readers), and clear each reader atomically.
-		 */
-		for (i = env->me_close_readers; --i >= 0; )
-			if (env->me_txns->mti_readers[i].mr_pid == pid)
-				env->me_txns->mti_readers[i].mr_pid = 0;
-#ifdef _WIN32
-		if (env->me_rmutex) {
-			CloseHandle(env->me_rmutex);
-			if (env->me_wmutex) CloseHandle(env->me_wmutex);
-		}
-		/* Windows automatically destroys the mutexes when
-		 * the last handle closes.
-		 */
-#elif defined(MDB_USE_POSIX_SEM)
-		if (env->me_rmutex != SEM_FAILED) {
-			sem_close(env->me_rmutex);
-			if (env->me_wmutex != SEM_FAILED)
-				sem_close(env->me_wmutex);
-			/* If we have the filelock:  If we are the
-			 * only remaining user, clean up semaphores.
-			 */
-			if (excl == 0)
-				mdb_env_excl_lock(env, &excl);
-			if (excl > 0) {
-				sem_unlink(env->me_txns->mti_rmname);
-				sem_unlink(env->me_txns->mti_wmname);
-			}
-		}
-#elif defined(MDB_USE_SYSV_SEM)
-		if (env->me_rmutex->semid != -1) {
-			/* If we have the filelock:  If we are the
-			 * only remaining user, clean up semaphores.
-			 */
-			if (excl == 0)
-				mdb_env_excl_lock(env, &excl);
-			if (excl > 0)
-				semctl(env->me_rmutex->semid, 0, IPC_RMID);
-		}
-#endif
-		munmap((void *)env->me_txns, (env->me_maxreaders-1)*sizeof(MDB_reader)+sizeof(MDB_txninfo));
-	}
-	if (env->me_lfd != INVALID_HANDLE_VALUE) {
-#ifdef _WIN32
-		if (excl >= 0) {
-			/* Unlock the lockfile.  Windows would have unlocked it
-			 * after closing anyway, but not necessarily at once.
-			 */
-			UnlockFile(env->me_lfd, 0, 0, 1, 0);
-		}
-#endif
-		(void) close(env->me_lfd);
-	}
-#ifdef MDB_VL32
-#ifdef _WIN32
-	if (env->me_fmh) CloseHandle(env->me_fmh);
-	if (env->me_rpmutex) CloseHandle(env->me_rpmutex);
-#else
-	pthread_mutex_destroy(&env->me_rpmutex);
-#endif
-#endif
-
-	env->me_flags &= ~(MDB_ENV_ACTIVE|MDB_ENV_TXKEY);
-}
-
-void ESECT
-mdb_env_close(MDB_env *env)
-{
-	MDB_page *dp;
-
-	if (env == NULL)
-		return;
-
-	VGMEMP_DESTROY(env);
-	while ((dp = env->me_dpages) != NULL) {
-		VGMEMP_DEFINED(&dp->mp_next, sizeof(dp->mp_next));
-		env->me_dpages = dp->mp_next;
-		free(dp);
-	}
-
-	mdb_env_close0(env, 0);
-	free(env);
-}
-
-/** Compare two items pointing at aligned mdb_size_t's */
-static int
-mdb_cmp_long(const MDB_val *a, const MDB_val *b)
-{
-	return (*(mdb_size_t *)a->mv_data < *(mdb_size_t *)b->mv_data) ? -1 :
-		*(mdb_size_t *)a->mv_data > *(mdb_size_t *)b->mv_data;
-}
-
-/** Compare two items pointing at aligned unsigned int's.
- *
- *	This is also set as #MDB_INTEGERDUP|#MDB_DUPFIXED's #MDB_dbx.%md_dcmp,
- *	but #mdb_cmp_clong() is called instead if the data type is mdb_size_t.
- */
-static int
-mdb_cmp_int(const MDB_val *a, const MDB_val *b)
-{
-	return (*(unsigned int *)a->mv_data < *(unsigned int *)b->mv_data) ? -1 :
-		*(unsigned int *)a->mv_data > *(unsigned int *)b->mv_data;
-}
-
-/** Compare two items pointing at unsigned ints of unknown alignment.
- *	Nodes and keys are guaranteed to be 2-byte aligned.
- */
-static int
-mdb_cmp_cint(const MDB_val *a, const MDB_val *b)
-{
-#if BYTE_ORDER == LITTLE_ENDIAN
-	unsigned short *u, *c;
-	int x;
-
-	u = (unsigned short *) ((char *) a->mv_data + a->mv_size);
-	c = (unsigned short *) ((char *) b->mv_data + a->mv_size);
-	do {
-		x = *--u - *--c;
-	} while(!x && u > (unsigned short *)a->mv_data);
-	return x;
-#else
-	unsigned short *u, *c, *end;
-	int x;
-
-	end = (unsigned short *) ((char *) a->mv_data + a->mv_size);
-	u = (unsigned short *)a->mv_data;
-	c = (unsigned short *)b->mv_data;
-	do {
-		x = *u++ - *c++;
-	} while(!x && u < end);
-	return x;
-#endif
-}
-
-/** Compare two items lexically */
-static int
-mdb_cmp_memn(const MDB_val *a, const MDB_val *b)
-{
-	int diff;
-	ssize_t len_diff;
-	unsigned int len;
-
-	len = a->mv_size;
-	len_diff = (ssize_t) a->mv_size - (ssize_t) b->mv_size;
-	if (len_diff > 0) {
-		len = b->mv_size;
-		len_diff = 1;
-	}
-
-	diff = memcmp(a->mv_data, b->mv_data, len);
-	return diff ? diff : len_diff<0 ? -1 : len_diff;
-}
-
-/** Compare two items in reverse byte order */
-static int
-mdb_cmp_memnr(const MDB_val *a, const MDB_val *b)
-{
-	const unsigned char	*p1, *p2, *p1_lim;
-	ssize_t len_diff;
-	int diff;
-
-	p1_lim = (const unsigned char *)a->mv_data;
-	p1 = (const unsigned char *)a->mv_data + a->mv_size;
-	p2 = (const unsigned char *)b->mv_data + b->mv_size;
-
-	len_diff = (ssize_t) a->mv_size - (ssize_t) b->mv_size;
-	if (len_diff > 0) {
-		p1_lim += len_diff;
-		len_diff = 1;
-	}
-
-	while (p1 > p1_lim) {
-		diff = *--p1 - *--p2;
-		if (diff)
-			return diff;
-	}
-	return len_diff<0 ? -1 : len_diff;
-}
-
-/** Search for key within a page, using binary search.
- * Returns the smallest entry larger or equal to the key.
- * If exactp is non-null, stores whether the found entry was an exact match
- * in *exactp (1 or 0).
- * Updates the cursor index with the index of the found entry.
- * If no entry larger or equal to the key is found, returns NULL.
- */
-static MDB_node *
-mdb_node_search(MDB_cursor *mc, MDB_val *key, int *exactp)
-{
-	unsigned int	 i = 0, nkeys;
-	int		 low, high;
-	int		 rc = 0;
-	MDB_page *mp = mc->mc_pg[mc->mc_top];
-	MDB_node	*node = NULL;
-	MDB_val	 nodekey;
-	MDB_cmp_func *cmp;
-	DKBUF;
-
-	nkeys = NUMKEYS(mp);
-
-	DPRINTF(("searching %u keys in %s %spage %"Y"u",
-	    nkeys, IS_LEAF(mp) ? "leaf" : "branch", IS_SUBP(mp) ? "sub-" : "",
-	    mdb_dbg_pgno(mp)));
-
-	low = IS_LEAF(mp) ? 0 : 1;
-	high = nkeys - 1;
-	cmp = mc->mc_dbx->md_cmp;
-
-	/* Branch pages have no data, so if using integer keys,
-	 * alignment is guaranteed. Use faster mdb_cmp_int.
-	 */
-	if (cmp == mdb_cmp_cint && IS_BRANCH(mp)) {
-		if (NODEPTR(mp, 1)->mn_ksize == sizeof(mdb_size_t))
-			cmp = mdb_cmp_long;
-		else if(NODEPTR(mp, 1)->mn_ksize == sizeof(int))
-			cmp = mdb_cmp_int;
-	}
-
-	if (IS_LEAF2(mp)) {
-		nodekey.mv_size = mc->mc_db->md_pad;
-		node = NODEPTR(mp, 0);	/* fake */
-		while (low <= high) {
-			i = (low + high) >> 1;
-			nodekey.mv_data = LEAF2KEY(mp, i, nodekey.mv_size);
-			rc = cmp(key, &nodekey);
-			DPRINTF(("found leaf index %u [%s], rc = %i",
-			    i, DKEY(&nodekey), rc));
-			if (rc == 0)
-				break;
-			if (rc > 0)
-				low = i + 1;
-			else
-				high = i - 1;
-		}
-	} else {
-		while (low <= high) {
-			i = (low + high) >> 1;
-
-			node = NODEPTR(mp, i);
-			nodekey.mv_size = NODEKSZ(node);
-			nodekey.mv_data = NODEKEY(node);
-
-			rc = cmp(key, &nodekey);
-#if MDB_DEBUG
-			if (IS_LEAF(mp))
-				DPRINTF(("found leaf index %u [%s], rc = %i",
-				    i, DKEY(&nodekey), rc));
-			else
-				DPRINTF(("found branch index %u [%s -> %"Y"u], rc = %i",
-				    i, DKEY(&nodekey), NODEPGNO(node), rc));
-#endif
-			if (rc == 0)
-				break;
-			if (rc > 0)
-				low = i + 1;
-			else
-				high = i - 1;
-		}
-	}
-
-	if (rc > 0) {	/* Found entry is less than the key. */
-		i++;	/* Skip to get the smallest entry larger than key. */
-		if (!IS_LEAF2(mp))
-			node = NODEPTR(mp, i);
-	}
-	if (exactp)
-		*exactp = (rc == 0 && nkeys > 0);
-	/* store the key index */
-	mc->mc_ki[mc->mc_top] = i;
-	if (i >= nkeys)
-		/* There is no entry larger or equal to the key. */
-		return NULL;
-
-	/* nodeptr is fake for LEAF2 */
-	return node;
-}
-
-#if 0
-static void
-mdb_cursor_adjust(MDB_cursor *mc, func)
-{
-	MDB_cursor *m2;
-
-	for (m2 = mc->mc_txn->mt_cursors[mc->mc_dbi]; m2; m2=m2->mc_next) {
-		if (m2->mc_pg[m2->mc_top] == mc->mc_pg[mc->mc_top]) {
-			func(mc, m2);
-		}
-	}
-}
-#endif
-
-/** Pop a page off the top of the cursor's stack. */
-static void
-mdb_cursor_pop(MDB_cursor *mc)
-{
-	if (mc->mc_snum) {
-		DPRINTF(("popping page %"Y"u off db %d cursor %p",
-			mc->mc_pg[mc->mc_top]->mp_pgno, DDBI(mc), (void *) mc));
-
-		mc->mc_snum--;
-		if (mc->mc_snum) {
-			mc->mc_top--;
-		} else {
-			mc->mc_flags &= ~C_INITIALIZED;
-		}
-	}
-}
-
-/** Push a page onto the top of the cursor's stack. */
-static int
-mdb_cursor_push(MDB_cursor *mc, MDB_page *mp)
-{
-	DPRINTF(("pushing page %"Y"u on db %d cursor %p", mp->mp_pgno,
-		DDBI(mc), (void *) mc));
-
-	if (mc->mc_snum >= CURSOR_STACK) {
-		mc->mc_txn->mt_flags |= MDB_TXN_ERROR;
-		return MDB_CURSOR_FULL;
-	}
-
-	mc->mc_top = mc->mc_snum++;
-	mc->mc_pg[mc->mc_top] = mp;
-	mc->mc_ki[mc->mc_top] = 0;
-
-	return MDB_SUCCESS;
-}
-
-#ifdef MDB_VL32
-/** Map a read-only page.
- * There are two levels of tracking in use, a per-txn list and a per-env list.
- * ref'ing and unref'ing the per-txn list is faster since it requires no
- * locking. Pages are cached in the per-env list for global reuse, and a lock
- * is required. Pages are not immediately unmapped when their refcnt goes to
- * zero; they hang around in case they will be reused again soon.
- *
- * When the per-txn list gets full, all pages with refcnt=0 are purged from the
- * list and their refcnts in the per-env list are decremented.
- *
- * When the per-env list gets full, all pages with refcnt=0 are purged from the
- * list and their pages are unmapped.
- *
- * @note "full" means the list has reached its respective rpcheck threshold.
- * This threshold slowly raises if no pages could be purged on a given check,
- * and returns to its original value when enough pages were purged.
- *
- * If purging doesn't free any slots, filling the per-txn list will return
- * MDB_TXN_FULL, and filling the per-env list returns MDB_MAP_FULL.
- *
- * Reference tracking in a txn is imperfect, pages can linger with non-zero
- * refcnt even without active references. It was deemed to be too invasive
- * to add unrefs in every required location. However, all pages are unref'd
- * at the end of the transaction. This guarantees that no stale references
- * linger in the per-env list.
- *
- * Usually we map chunks of 16 pages at a time, but if an overflow page begins
- * at the tail of the chunk we extend the chunk to include the entire overflow
- * page. Unfortunately, pages can be turned into overflow pages after their
- * chunk was already mapped. In that case we must remap the chunk if the
- * overflow page is referenced. If the chunk's refcnt is 0 we can just remap
- * it, otherwise we temporarily map a new chunk just for the overflow page.
- *
- * @note this chunk handling means we cannot guarantee that a data item
- * returned from the DB will stay alive for the duration of the transaction:
- *   We unref pages as soon as a cursor moves away from the page
- *   A subsequent op may cause a purge, which may unmap any unref'd chunks
- * The caller must copy the data if it must be used later in the same txn.
- *
- * Also - our reference counting revolves around cursors, but overflow pages
- * aren't pointed to by a cursor's page stack. We have to remember them
- * explicitly, in the added mc_ovpg field. A single cursor can only hold a
- * reference to one overflow page at a time.
- *
- * @param[in] txn the transaction for this access.
- * @param[in] pgno the page number for the page to retrieve.
- * @param[out] ret address of a pointer where the page's address will be stored.
- * @return 0 on success, non-zero on failure.
- */
-static int
-mdb_rpage_get(MDB_txn *txn, pgno_t pg0, MDB_page **ret)
-{
-	MDB_env *env = txn->mt_env;
-	MDB_page *p;
-	MDB_ID3L tl = txn->mt_rpages;
-	MDB_ID3L el = env->me_rpages;
-	MDB_ID3 id3;
-	unsigned x, rem;
-	pgno_t pgno;
-	int rc, retries = 1;
-#ifdef _WIN32
-	LARGE_INTEGER off;
-	SIZE_T len;
-#define SET_OFF(off,val)	off.QuadPart = val
-#define MAP(rc,env,addr,len,off)	\
-	addr = NULL; \
-	rc = NtMapViewOfSection(env->me_fmh, GetCurrentProcess(), &addr, 0, \
-		len, &off, &len, ViewUnmap, (env->me_flags & MDB_RDONLY) ? 0 : MEM_RESERVE, PAGE_READONLY); \
-	if (rc) rc = mdb_nt2win32(rc)
-#else
-	off_t off;
-	size_t len;
-#define SET_OFF(off,val)	off = val
-#define MAP(rc,env,addr,len,off)	\
-	addr = mmap(NULL, len, PROT_READ, MAP_SHARED, env->me_fd, off); \
-	rc = (addr == MAP_FAILED) ? errno : 0
-#endif
-
-	/* remember the offset of the actual page number, so we can
-	 * return the correct pointer at the end.
-	 */
-	rem = pg0 & (MDB_RPAGE_CHUNK-1);
-	pgno = pg0 ^ rem;
-
-	id3.mid = 0;
-	x = mdb_mid3l_search(tl, pgno);
-	if (x <= tl[0].mid && tl[x].mid == pgno) {
-		if (x != tl[0].mid && tl[x+1].mid == pg0)
-			x++;
-		/* check for overflow size */
-		p = (MDB_page *)((char *)tl[x].mptr + rem * env->me_psize);
-		if (IS_OVERFLOW(p) && p->mp_pages + rem > tl[x].mcnt) {
-			id3.mcnt = p->mp_pages + rem;
-			len = id3.mcnt * env->me_psize;
-			SET_OFF(off, pgno * env->me_psize);
-			MAP(rc, env, id3.mptr, len, off);
-			if (rc)
-				return rc;
-			/* check for local-only page */
-			if (rem) {
-				mdb_tassert(txn, tl[x].mid != pg0);
-				/* hope there's room to insert this locally.
-				 * setting mid here tells later code to just insert
-				 * this id3 instead of searching for a match.
-				 */
-				id3.mid = pg0;
-				goto notlocal;
-			} else {
-				/* ignore the mapping we got from env, use new one */
-				tl[x].mptr = id3.mptr;
-				tl[x].mcnt = id3.mcnt;
-				/* if no active ref, see if we can replace in env */
-				if (!tl[x].mref) {
-					unsigned i;
-					pthread_mutex_lock(&env->me_rpmutex);
-					i = mdb_mid3l_search(el, tl[x].mid);
-					if (el[i].mref == 1) {
-						/* just us, replace it */
-						munmap(el[i].mptr, el[i].mcnt * env->me_psize);
-						el[i].mptr = tl[x].mptr;
-						el[i].mcnt = tl[x].mcnt;
-					} else {
-						/* there are others, remove ourself */
-						el[i].mref--;
-					}
-					pthread_mutex_unlock(&env->me_rpmutex);
-				}
-			}
-		}
-		id3.mptr = tl[x].mptr;
-		id3.mcnt = tl[x].mcnt;
-		tl[x].mref++;
-		goto ok;
-	}
-
-notlocal:
-	if (tl[0].mid >= MDB_TRPAGE_MAX - txn->mt_rpcheck) {
-		unsigned i, y;
-		/* purge unref'd pages from our list and unref in env */
-		pthread_mutex_lock(&env->me_rpmutex);
-retry:
-		y = 0;
-		for (i=1; i<=tl[0].mid; i++) {
-			if (!tl[i].mref) {
-				if (!y) y = i;
-				/* tmp overflow pages don't go to env */
-				if (tl[i].mid & (MDB_RPAGE_CHUNK-1)) {
-					munmap(tl[i].mptr, tl[i].mcnt * env->me_psize);
-					continue;
-				}
-				x = mdb_mid3l_search(el, tl[i].mid);
-				el[x].mref--;
-			}
-		}
-		pthread_mutex_unlock(&env->me_rpmutex);
-		if (!y) {
-			/* we didn't find any unref'd chunks.
-			 * if we're out of room, fail.
-			 */
-			if (tl[0].mid >= MDB_TRPAGE_MAX)
-				return MDB_TXN_FULL;
-			/* otherwise, raise threshold for next time around
-			 * and let this go.
-			 */
-			txn->mt_rpcheck /= 2;
-		} else {
-			/* we found some unused; consolidate the list */
-			for (i=y+1; i<= tl[0].mid; i++)
-				if (tl[i].mref)
-					tl[y++] = tl[i];
-			tl[0].mid = y-1;
-			/* decrease the check threshold toward its original value */
-			if (!txn->mt_rpcheck)
-				txn->mt_rpcheck = 1;
-			while (txn->mt_rpcheck < tl[0].mid && txn->mt_rpcheck < MDB_TRPAGE_SIZE/2)
-				txn->mt_rpcheck *= 2;
-		}
-	}
-	if (tl[0].mid < MDB_TRPAGE_SIZE) {
-		id3.mref = 1;
-		if (id3.mid)
-			goto found;
-		/* don't map past last written page in read-only envs */
-		if ((env->me_flags & MDB_RDONLY) && pgno + MDB_RPAGE_CHUNK-1 > txn->mt_last_pgno)
-			id3.mcnt = txn->mt_last_pgno + 1 - pgno;
-		else
-			id3.mcnt = MDB_RPAGE_CHUNK;
-		len = id3.mcnt * env->me_psize;
-		id3.mid = pgno;
-
-		/* search for page in env */
-		pthread_mutex_lock(&env->me_rpmutex);
-		x = mdb_mid3l_search(el, pgno);
-		if (x <= el[0].mid && el[x].mid == pgno) {
-			id3.mptr = el[x].mptr;
-			id3.mcnt = el[x].mcnt;
-			/* check for overflow size */
-			p = (MDB_page *)((char *)id3.mptr + rem * env->me_psize);
-			if (IS_OVERFLOW(p) && p->mp_pages + rem > id3.mcnt) {
-				id3.mcnt = p->mp_pages + rem;
-				len = id3.mcnt * env->me_psize;
-				SET_OFF(off, pgno * env->me_psize);
-				MAP(rc, env, id3.mptr, len, off);
-				if (rc)
-					goto fail;
-				if (!el[x].mref) {
-					munmap(el[x].mptr, env->me_psize * el[x].mcnt);
-					el[x].mptr = id3.mptr;
-					el[x].mcnt = id3.mcnt;
-				} else {
-					id3.mid = pg0;
-					pthread_mutex_unlock(&env->me_rpmutex);
-					goto found;
-				}
-			}
-			el[x].mref++;
-			pthread_mutex_unlock(&env->me_rpmutex);
-			goto found;
-		}
-		if (el[0].mid >= MDB_ERPAGE_MAX - env->me_rpcheck) {
-			/* purge unref'd pages */
-			unsigned i, y = 0;
-			for (i=1; i<=el[0].mid; i++) {
-				if (!el[i].mref) {
-					if (!y) y = i;
-					munmap(el[i].mptr, env->me_psize * el[i].mcnt);
-				}
-			}
-			if (!y) {
-				if (retries) {
-					/* see if we can unref some local pages */
-					retries--;
-					id3.mid = 0;
-					goto retry;
-				}
-				if (el[0].mid >= MDB_ERPAGE_MAX) {
-					pthread_mutex_unlock(&env->me_rpmutex);
-					return MDB_MAP_FULL;
-				}
-				env->me_rpcheck /= 2;
-			} else {
-				for (i=y+1; i<= el[0].mid; i++)
-					if (el[i].mref)
-						el[y++] = el[i];
-				el[0].mid = y-1;
-				if (!env->me_rpcheck)
-					env->me_rpcheck = 1;
-				while (env->me_rpcheck < el[0].mid && env->me_rpcheck < MDB_ERPAGE_SIZE/2)
-					env->me_rpcheck *= 2;
-			}
-		}
-		SET_OFF(off, pgno * env->me_psize);
-		MAP(rc, env, id3.mptr, len, off);
-		if (rc) {
-fail:
-			pthread_mutex_unlock(&env->me_rpmutex);
-			return rc;
-		}
-		/* check for overflow size */
-		p = (MDB_page *)((char *)id3.mptr + rem * env->me_psize);
-		if (IS_OVERFLOW(p) && p->mp_pages + rem > id3.mcnt) {
-			id3.mcnt = p->mp_pages + rem;
-			munmap(id3.mptr, len);
-			len = id3.mcnt * env->me_psize;
-			MAP(rc, env, id3.mptr, len, off);
-			if (rc)
-				goto fail;
-		}
-		mdb_mid3l_insert(el, &id3);
-		pthread_mutex_unlock(&env->me_rpmutex);
-found:
-		mdb_mid3l_insert(tl, &id3);
-	} else {
-		return MDB_TXN_FULL;
-	}
-ok:
-	p = (MDB_page *)((char *)id3.mptr + rem * env->me_psize);
-#if MDB_DEBUG	/* we don't need this check any more */
-	if (IS_OVERFLOW(p)) {
-		mdb_tassert(txn, p->mp_pages + rem <= id3.mcnt);
-	}
-#endif
-	*ret = p;
-	return MDB_SUCCESS;
-}
-#endif
-
-/** Find the address of the page corresponding to a given page number.
- * @param[in] mc the cursor accessing the page.
- * @param[in] pgno the page number for the page to retrieve.
- * @param[out] ret address of a pointer where the page's address will be stored.
- * @param[out] lvl dirty_list inheritance level of found page. 1=current txn, 0=mapped page.
- * @return 0 on success, non-zero on failure.
- */
-static int
-mdb_page_get(MDB_cursor *mc, pgno_t pgno, MDB_page **ret, int *lvl)
-{
-	MDB_txn *txn = mc->mc_txn;
-#ifndef MDB_VL32
-	MDB_env *env = txn->mt_env;
-#endif
-	MDB_page *p = NULL;
-	int level;
-
-	if (! (mc->mc_flags & (C_ORIG_RDONLY|C_WRITEMAP))) {
-		MDB_txn *tx2 = txn;
-		level = 1;
-		do {
-			MDB_ID2L dl = tx2->mt_u.dirty_list;
-			unsigned x;
-			/* Spilled pages were dirtied in this txn and flushed
-			 * because the dirty list got full. Bring this page
-			 * back in from the map (but don't unspill it here,
-			 * leave that unless page_touch happens again).
-			 */
-			if (tx2->mt_spill_pgs) {
-				MDB_ID pn = pgno << 1;
-				x = mdb_midl_search(tx2->mt_spill_pgs, pn);
-				if (x <= tx2->mt_spill_pgs[0] && tx2->mt_spill_pgs[x] == pn) {
-#ifdef MDB_VL32
-					int rc = mdb_rpage_get(txn, pgno, &p);
-					if (rc)
-						return rc;
-#else
-					p = (MDB_page *)(env->me_map + env->me_psize * pgno);
-#endif
-					goto done;
-				}
-			}
-			if (dl[0].mid) {
-				unsigned x = mdb_mid2l_search(dl, pgno);
-				if (x <= dl[0].mid && dl[x].mid == pgno) {
-					p = dl[x].mptr;
-					goto done;
-				}
-			}
-			level++;
-		} while ((tx2 = tx2->mt_parent) != NULL);
-	}
-
-	if (pgno < txn->mt_next_pgno) {
-		level = 0;
-#ifdef MDB_VL32
-		{
-			int rc = mdb_rpage_get(txn, pgno, &p);
-			if (rc)
-				return rc;
-		}
-#else
-		p = (MDB_page *)(env->me_map + env->me_psize * pgno);
-#endif
-	} else {
-		DPRINTF(("page %"Y"u not found", pgno));
-		txn->mt_flags |= MDB_TXN_ERROR;
-		return MDB_PAGE_NOTFOUND;
-	}
-
-done:
-	*ret = p;
-	if (lvl)
-		*lvl = level;
-	return MDB_SUCCESS;
-}
-
-/** Finish #mdb_page_search() / #mdb_page_search_lowest().
- *	The cursor is at the root page, set up the rest of it.
- */
-static int
-mdb_page_search_root(MDB_cursor *mc, MDB_val *key, int flags)
-{
-	MDB_page	*mp = mc->mc_pg[mc->mc_top];
-	int rc;
-	DKBUF;
-
-	while (IS_BRANCH(mp)) {
-		MDB_node	*node;
-		indx_t		i;
-
-		DPRINTF(("branch page %"Y"u has %u keys", mp->mp_pgno, NUMKEYS(mp)));
-		/* Don't assert on branch pages in the FreeDB. We can get here
-		 * while in the process of rebalancing a FreeDB branch page; we must
-		 * let that proceed. ITS#8336
-		 */
-		mdb_cassert(mc, !mc->mc_dbi || NUMKEYS(mp) > 1);
-		DPRINTF(("found index 0 to page %"Y"u", NODEPGNO(NODEPTR(mp, 0))));
-
-		if (flags & (MDB_PS_FIRST|MDB_PS_LAST)) {
-			i = 0;
-			if (flags & MDB_PS_LAST)
-				i = NUMKEYS(mp) - 1;
-		} else {
-			int	 exact;
-			node = mdb_node_search(mc, key, &exact);
-			if (node == NULL)
-				i = NUMKEYS(mp) - 1;
-			else {
-				i = mc->mc_ki[mc->mc_top];
-				if (!exact) {
-					mdb_cassert(mc, i > 0);
-					i--;
-				}
-			}
-			DPRINTF(("following index %u for key [%s]", i, DKEY(key)));
-		}
-
-		mdb_cassert(mc, i < NUMKEYS(mp));
-		node = NODEPTR(mp, i);
-
-		if ((rc = mdb_page_get(mc, NODEPGNO(node), &mp, NULL)) != 0)
-			return rc;
-
-		mc->mc_ki[mc->mc_top] = i;
-		if ((rc = mdb_cursor_push(mc, mp)))
-			return rc;
-
-		if (flags & MDB_PS_MODIFY) {
-			if ((rc = mdb_page_touch(mc)) != 0)
-				return rc;
-			mp = mc->mc_pg[mc->mc_top];
-		}
-	}
-
-	if (!IS_LEAF(mp)) {
-		DPRINTF(("internal error, index points to a %02X page!?",
-		    mp->mp_flags));
-		mc->mc_txn->mt_flags |= MDB_TXN_ERROR;
-		return MDB_CORRUPTED;
-	}
-
-	DPRINTF(("found leaf page %"Y"u for key [%s]", mp->mp_pgno,
-	    key ? DKEY(key) : "null"));
-	mc->mc_flags |= C_INITIALIZED;
-	mc->mc_flags &= ~C_EOF;
-
-	return MDB_SUCCESS;
-}
-
-/** Search for the lowest key under the current branch page.
- * This just bypasses a NUMKEYS check in the current page
- * before calling mdb_page_search_root(), because the callers
- * are all in situations where the current page is known to
- * be underfilled.
- */
-static int
-mdb_page_search_lowest(MDB_cursor *mc)
-{
-	MDB_page	*mp = mc->mc_pg[mc->mc_top];
-	MDB_node	*node = NODEPTR(mp, 0);
-	int rc;
-
-	if ((rc = mdb_page_get(mc, NODEPGNO(node), &mp, NULL)) != 0)
-		return rc;
-
-	mc->mc_ki[mc->mc_top] = 0;
-	if ((rc = mdb_cursor_push(mc, mp)))
-		return rc;
-	return mdb_page_search_root(mc, NULL, MDB_PS_FIRST);
-}
-
-/** Search for the page a given key should be in.
- * Push it and its parent pages on the cursor stack.
- * @param[in,out] mc the cursor for this operation.
- * @param[in] key the key to search for, or NULL for first/last page.
- * @param[in] flags If MDB_PS_MODIFY is set, visited pages in the DB
- *   are touched (updated with new page numbers).
- *   If MDB_PS_FIRST or MDB_PS_LAST is set, find first or last leaf.
- *   This is used by #mdb_cursor_first() and #mdb_cursor_last().
- *   If MDB_PS_ROOTONLY set, just fetch root node, no further lookups.
- * @return 0 on success, non-zero on failure.
- */
-static int
-mdb_page_search(MDB_cursor *mc, MDB_val *key, int flags)
-{
-	int		 rc;
-	pgno_t		 root;
-
-	/* Make sure the txn is still viable, then find the root from
-	 * the txn's db table and set it as the root of the cursor's stack.
-	 */
-	if (mc->mc_txn->mt_flags & MDB_TXN_BLOCKED) {
-		DPUTS("transaction may not be used now");
-		return MDB_BAD_TXN;
-	} else {
-		/* Make sure we're using an up-to-date root */
-		if (*mc->mc_dbflag & DB_STALE) {
-				MDB_cursor mc2;
-				if (TXN_DBI_CHANGED(mc->mc_txn, mc->mc_dbi))
-					return MDB_BAD_DBI;
-				mdb_cursor_init(&mc2, mc->mc_txn, MAIN_DBI, NULL);
-				rc = mdb_page_search(&mc2, &mc->mc_dbx->md_name, 0);
-				if (rc)
-					return rc;
-				{
-					MDB_val data;
-					int exact = 0;
-					uint16_t flags;
-					MDB_node *leaf = mdb_node_search(&mc2,
-						&mc->mc_dbx->md_name, &exact);
-					if (!exact)
-						return MDB_NOTFOUND;
-					if ((leaf->mn_flags & (F_DUPDATA|F_SUBDATA)) != F_SUBDATA)
-						return MDB_INCOMPATIBLE; /* not a named DB */
-					rc = mdb_node_read(&mc2, leaf, &data);
-					if (rc)
-						return rc;
-					memcpy(&flags, ((char *) data.mv_data + offsetof(MDB_db, md_flags)),
-						sizeof(uint16_t));
-					/* The txn may not know this DBI, or another process may
-					 * have dropped and recreated the DB with other flags.
-					 */
-					if ((mc->mc_db->md_flags & PERSISTENT_FLAGS) != flags)
-						return MDB_INCOMPATIBLE;
-					memcpy(mc->mc_db, data.mv_data, sizeof(MDB_db));
-				}
-				*mc->mc_dbflag &= ~DB_STALE;
-		}
-		root = mc->mc_db->md_root;
-
-		if (root == P_INVALID) {		/* Tree is empty. */
-			DPUTS("tree is empty");
-			return MDB_NOTFOUND;
-		}
-	}
-
-	mdb_cassert(mc, root > 1);
-	if (!mc->mc_pg[0] || mc->mc_pg[0]->mp_pgno != root) {
-#ifdef MDB_VL32
-		if (mc->mc_pg[0])
-			MDB_PAGE_UNREF(mc->mc_txn, mc->mc_pg[0]);
-#endif
-		if ((rc = mdb_page_get(mc, root, &mc->mc_pg[0], NULL)) != 0)
-			return rc;
-	}
-
-#ifdef MDB_VL32
-	{
-		int i;
-		for (i=1; i<mc->mc_snum; i++)
-			MDB_PAGE_UNREF(mc->mc_txn, mc->mc_pg[i]);
-	}
-#endif
-	mc->mc_snum = 1;
-	mc->mc_top = 0;
-
-	DPRINTF(("db %d root page %"Y"u has flags 0x%X",
-		DDBI(mc), root, mc->mc_pg[0]->mp_flags));
-
-	if (flags & MDB_PS_MODIFY) {
-		if ((rc = mdb_page_touch(mc)))
-			return rc;
-	}
-
-	if (flags & MDB_PS_ROOTONLY)
-		return MDB_SUCCESS;
-
-	return mdb_page_search_root(mc, key, flags);
-}
-
-static int
-mdb_ovpage_free(MDB_cursor *mc, MDB_page *mp)
-{
-	MDB_txn *txn = mc->mc_txn;
-	pgno_t pg = mp->mp_pgno;
-	unsigned x = 0, ovpages = mp->mp_pages;
-	MDB_env *env = txn->mt_env;
-	MDB_IDL sl = txn->mt_spill_pgs;
-	MDB_ID pn = pg << 1;
-	int rc;
-
-	DPRINTF(("free ov page %"Y"u (%d)", pg, ovpages));
-	/* If the page is dirty or on the spill list we just acquired it,
-	 * so we should give it back to our current free list, if any.
-	 * Otherwise put it onto the list of pages we freed in this txn.
-	 *
-	 * Won't create me_pghead: me_pglast must be inited along with it.
-	 * Unsupported in nested txns: They would need to hide the page
-	 * range in ancestor txns' dirty and spilled lists.
-	 */
-	if (env->me_pghead &&
-		!txn->mt_parent &&
-		((mp->mp_flags & P_DIRTY) ||
-		 (sl && (x = mdb_midl_search(sl, pn)) <= sl[0] && sl[x] == pn)))
-	{
-		unsigned i, j;
-		pgno_t *mop;
-		MDB_ID2 *dl, ix, iy;
-		rc = mdb_midl_need(&env->me_pghead, ovpages);
-		if (rc)
-			return rc;
-		if (!(mp->mp_flags & P_DIRTY)) {
-			/* This page is no longer spilled */
-			if (x == sl[0])
-				sl[0]--;
-			else
-				sl[x] |= 1;
-			goto release;
-		}
-		/* Remove from dirty list */
-		dl = txn->mt_u.dirty_list;
-		x = dl[0].mid--;
-		for (ix = dl[x]; ix.mptr != mp; ix = iy) {
-			if (x > 1) {
-				x--;
-				iy = dl[x];
-				dl[x] = ix;
-			} else {
-				mdb_cassert(mc, x > 1);
-				j = ++(dl[0].mid);
-				dl[j] = ix;		/* Unsorted. OK when MDB_TXN_ERROR. */
-				txn->mt_flags |= MDB_TXN_ERROR;
-				return MDB_CORRUPTED;
-			}
-		}
-		txn->mt_dirty_room++;
-		if (!(env->me_flags & MDB_WRITEMAP))
-			mdb_dpage_free(env, mp);
-release:
-		/* Insert in me_pghead */
-		mop = env->me_pghead;
-		j = mop[0] + ovpages;
-		for (i = mop[0]; i && mop[i] < pg; i--)
-			mop[j--] = mop[i];
-		while (j>i)
-			mop[j--] = pg++;
-		mop[0] += ovpages;
-	} else {
-		rc = mdb_midl_append_range(&txn->mt_free_pgs, pg, ovpages);
-		if (rc)
-			return rc;
-	}
-	mc->mc_db->md_overflow_pages -= ovpages;
-	return 0;
-}
-
-/** Return the data associated with a given node.
- * @param[in] mc The cursor for this operation.
- * @param[in] leaf The node being read.
- * @param[out] data Updated to point to the node's data.
- * @return 0 on success, non-zero on failure.
- */
-static int
-mdb_node_read(MDB_cursor *mc, MDB_node *leaf, MDB_val *data)
-{
-	MDB_page	*omp;		/* overflow page */
-	pgno_t		 pgno;
-	int rc;
-
-#ifdef MDB_VL32
-	if (mc->mc_ovpg) {
-		MDB_PAGE_UNREF(mc->mc_txn, mc->mc_ovpg);
-		mc->mc_ovpg = 0;
-	}
-#endif
-	if (!F_ISSET(leaf->mn_flags, F_BIGDATA)) {
-		data->mv_size = NODEDSZ(leaf);
-		data->mv_data = NODEDATA(leaf);
-		return MDB_SUCCESS;
-	}
-
-	/* Read overflow data.
-	 */
-	data->mv_size = NODEDSZ(leaf);
-	memcpy(&pgno, NODEDATA(leaf), sizeof(pgno));
-	if ((rc = mdb_page_get(mc, pgno, &omp, NULL)) != 0) {
-		DPRINTF(("read overflow page %"Y"u failed", pgno));
-		return rc;
-	}
-	data->mv_data = METADATA(omp);
-#ifdef MDB_VL32
-	mc->mc_ovpg = omp;
-#endif
-
-	return MDB_SUCCESS;
-}
-
-int
-mdb_get(MDB_txn *txn, MDB_dbi dbi,
-    MDB_val *key, MDB_val *data)
-{
-	MDB_cursor	mc;
-	MDB_xcursor	mx;
-	int exact = 0, rc;
-	DKBUF;
-
-	DPRINTF(("===> get db %u key [%s]", dbi, DKEY(key)));
-
-	if (!key || !data || !TXN_DBI_EXIST(txn, dbi, DB_USRVALID))
-		return EINVAL;
-
-	if (txn->mt_flags & MDB_TXN_BLOCKED)
-		return MDB_BAD_TXN;
-
-	mdb_cursor_init(&mc, txn, dbi, &mx);
-	rc = mdb_cursor_set(&mc, key, data, MDB_SET, &exact);
-#ifdef MDB_VL32
-	{
-		/* unref all the pages - caller must copy the data
-		 * before doing anything else
-		 */
-		mdb_cursor_unref(&mc);
-	}
-#endif
-	return rc;
-}
-
-/** Find a sibling for a page.
- * Replaces the page at the top of the cursor's stack with the
- * specified sibling, if one exists.
- * @param[in] mc The cursor for this operation.
- * @param[in] move_right Non-zero if the right sibling is requested,
- * otherwise the left sibling.
- * @return 0 on success, non-zero on failure.
- */
-static int
-mdb_cursor_sibling(MDB_cursor *mc, int move_right)
-{
-	int		 rc;
-	MDB_node	*indx;
-	MDB_page	*mp;
-#ifdef MDB_VL32
-	MDB_page	*op;
-#endif
-
-	if (mc->mc_snum < 2) {
-		return MDB_NOTFOUND;		/* root has no siblings */
-	}
-
-#ifdef MDB_VL32
-	op = mc->mc_pg[mc->mc_top];
-#endif
-	mdb_cursor_pop(mc);
-	DPRINTF(("parent page is page %"Y"u, index %u",
-		mc->mc_pg[mc->mc_top]->mp_pgno, mc->mc_ki[mc->mc_top]));
-
-	if (move_right ? (mc->mc_ki[mc->mc_top] + 1u >= NUMKEYS(mc->mc_pg[mc->mc_top]))
-		       : (mc->mc_ki[mc->mc_top] == 0)) {
-		DPRINTF(("no more keys left, moving to %s sibling",
-		    move_right ? "right" : "left"));
-		if ((rc = mdb_cursor_sibling(mc, move_right)) != MDB_SUCCESS) {
-			/* undo cursor_pop before returning */
-			mc->mc_top++;
-			mc->mc_snum++;
-			return rc;
-		}
-	} else {
-		if (move_right)
-			mc->mc_ki[mc->mc_top]++;
-		else
-			mc->mc_ki[mc->mc_top]--;
-		DPRINTF(("just moving to %s index key %u",
-		    move_right ? "right" : "left", mc->mc_ki[mc->mc_top]));
-	}
-	mdb_cassert(mc, IS_BRANCH(mc->mc_pg[mc->mc_top]));
-
-	MDB_PAGE_UNREF(mc->mc_txn, op);
-
-	indx = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
-	if ((rc = mdb_page_get(mc, NODEPGNO(indx), &mp, NULL)) != 0) {
-		/* mc will be inconsistent if caller does mc_snum++ as above */
-		mc->mc_flags &= ~(C_INITIALIZED|C_EOF);
-		return rc;
-	}
-
-	mdb_cursor_push(mc, mp);
-	if (!move_right)
-		mc->mc_ki[mc->mc_top] = NUMKEYS(mp)-1;
-
-	return MDB_SUCCESS;
-}
-
-/** Move the cursor to the next data item. */
-static int
-mdb_cursor_next(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op)
-{
-	MDB_page	*mp;
-	MDB_node	*leaf;
-	int rc;
-
-	if (mc->mc_flags & C_EOF) {
-		return MDB_NOTFOUND;
-	}
-	if (!(mc->mc_flags & C_INITIALIZED))
-		return mdb_cursor_first(mc, key, data);
-
-	mp = mc->mc_pg[mc->mc_top];
-
-	if (mc->mc_db->md_flags & MDB_DUPSORT) {
-		leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
-		if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
-			if (op == MDB_NEXT || op == MDB_NEXT_DUP) {
-				rc = mdb_cursor_next(&mc->mc_xcursor->mx_cursor, data, NULL, MDB_NEXT);
-				if (op != MDB_NEXT || rc != MDB_NOTFOUND) {
-					if (rc == MDB_SUCCESS)
-						MDB_GET_KEY(leaf, key);
-					return rc;
-				}
-			}
-#ifdef MDB_VL32
-			else {
-				if (mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED) {
-					mdb_cursor_unref(&mc->mc_xcursor->mx_cursor);
-				}
-			}
-#endif
-		} else {
-			mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);
-			if (op == MDB_NEXT_DUP)
-				return MDB_NOTFOUND;
-		}
-	}
-
-	DPRINTF(("cursor_next: top page is %"Y"u in cursor %p",
-		mdb_dbg_pgno(mp), (void *) mc));
-	if (mc->mc_flags & C_DEL) {
-		mc->mc_flags ^= C_DEL;
-		goto skip;
-	}
-
-	if (mc->mc_ki[mc->mc_top] + 1u >= NUMKEYS(mp)) {
-		DPUTS("=====> move to next sibling page");
-		if ((rc = mdb_cursor_sibling(mc, 1)) != MDB_SUCCESS) {
-			mc->mc_flags |= C_EOF;
-			return rc;
-		}
-		mp = mc->mc_pg[mc->mc_top];
-		DPRINTF(("next page is %"Y"u, key index %u", mp->mp_pgno, mc->mc_ki[mc->mc_top]));
-	} else
-		mc->mc_ki[mc->mc_top]++;
-
-skip:
-	DPRINTF(("==> cursor points to page %"Y"u with %u keys, key index %u",
-	    mdb_dbg_pgno(mp), NUMKEYS(mp), mc->mc_ki[mc->mc_top]));
-
-	if (IS_LEAF2(mp)) {
-		key->mv_size = mc->mc_db->md_pad;
-		key->mv_data = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], key->mv_size);
-		return MDB_SUCCESS;
-	}
-
-	mdb_cassert(mc, IS_LEAF(mp));
-	leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
-
-	if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
-		mdb_xcursor_init1(mc, leaf);
-	}
-	if (data) {
-		if ((rc = mdb_node_read(mc, leaf, data)) != MDB_SUCCESS)
-			return rc;
-
-		if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
-			rc = mdb_cursor_first(&mc->mc_xcursor->mx_cursor, data, NULL);
-			if (rc != MDB_SUCCESS)
-				return rc;
-		}
-	}
-
-	MDB_GET_KEY(leaf, key);
-	return MDB_SUCCESS;
-}
-
-/** Move the cursor to the previous data item. */
-static int
-mdb_cursor_prev(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op)
-{
-	MDB_page	*mp;
-	MDB_node	*leaf;
-	int rc;
-
-	if (!(mc->mc_flags & C_INITIALIZED)) {
-		rc = mdb_cursor_last(mc, key, data);
-		if (rc)
-			return rc;
-		mc->mc_ki[mc->mc_top]++;
-	}
-
-	mp = mc->mc_pg[mc->mc_top];
-
-	if (mc->mc_db->md_flags & MDB_DUPSORT) {
-		leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
-		if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
-			if (op == MDB_PREV || op == MDB_PREV_DUP) {
-				rc = mdb_cursor_prev(&mc->mc_xcursor->mx_cursor, data, NULL, MDB_PREV);
-				if (op != MDB_PREV || rc != MDB_NOTFOUND) {
-					if (rc == MDB_SUCCESS) {
-						MDB_GET_KEY(leaf, key);
-						mc->mc_flags &= ~C_EOF;
-					}
-					return rc;
-				}
-			}
-#ifdef MDB_VL32
-			else {
-				if (mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED) {
-					mdb_cursor_unref(&mc->mc_xcursor->mx_cursor);
-				}
-			}
-#endif
-		} else {
-			mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);
-			if (op == MDB_PREV_DUP)
-				return MDB_NOTFOUND;
-		}
-	}
-
-	DPRINTF(("cursor_prev: top page is %"Y"u in cursor %p",
-		mdb_dbg_pgno(mp), (void *) mc));
-
-	mc->mc_flags &= ~(C_EOF|C_DEL);
-
-	if (mc->mc_ki[mc->mc_top] == 0)  {
-		DPUTS("=====> move to prev sibling page");
-		if ((rc = mdb_cursor_sibling(mc, 0)) != MDB_SUCCESS) {
-			return rc;
-		}
-		mp = mc->mc_pg[mc->mc_top];
-		mc->mc_ki[mc->mc_top] = NUMKEYS(mp) - 1;
-		DPRINTF(("prev page is %"Y"u, key index %u", mp->mp_pgno, mc->mc_ki[mc->mc_top]));
-	} else
-		mc->mc_ki[mc->mc_top]--;
-
-	mc->mc_flags &= ~C_EOF;
-
-	DPRINTF(("==> cursor points to page %"Y"u with %u keys, key index %u",
-	    mdb_dbg_pgno(mp), NUMKEYS(mp), mc->mc_ki[mc->mc_top]));
-
-	if (IS_LEAF2(mp)) {
-		key->mv_size = mc->mc_db->md_pad;
-		key->mv_data = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], key->mv_size);
-		return MDB_SUCCESS;
-	}
-
-	mdb_cassert(mc, IS_LEAF(mp));
-	leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
-
-	if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
-		mdb_xcursor_init1(mc, leaf);
-	}
-	if (data) {
-		if ((rc = mdb_node_read(mc, leaf, data)) != MDB_SUCCESS)
-			return rc;
-
-		if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
-			rc = mdb_cursor_last(&mc->mc_xcursor->mx_cursor, data, NULL);
-			if (rc != MDB_SUCCESS)
-				return rc;
-		}
-	}
-
-	MDB_GET_KEY(leaf, key);
-	return MDB_SUCCESS;
-}
-
-/** Set the cursor on a specific data item. */
-static int
-mdb_cursor_set(MDB_cursor *mc, MDB_val *key, MDB_val *data,
-    MDB_cursor_op op, int *exactp)
-{
-	int		 rc;
-	MDB_page	*mp;
-	MDB_node	*leaf = NULL;
-	DKBUF;
-
-	if (key->mv_size == 0)
-		return MDB_BAD_VALSIZE;
-
-	if (mc->mc_xcursor)
-		mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);
-
-	/* See if we're already on the right page */
-	if (mc->mc_flags & C_INITIALIZED) {
-		MDB_val nodekey;
-
-		mp = mc->mc_pg[mc->mc_top];
-		if (!NUMKEYS(mp)) {
-			mc->mc_ki[mc->mc_top] = 0;
-			return MDB_NOTFOUND;
-		}
-		if (mp->mp_flags & P_LEAF2) {
-			nodekey.mv_size = mc->mc_db->md_pad;
-			nodekey.mv_data = LEAF2KEY(mp, 0, nodekey.mv_size);
-		} else {
-			leaf = NODEPTR(mp, 0);
-			MDB_GET_KEY2(leaf, nodekey);
-		}
-		rc = mc->mc_dbx->md_cmp(key, &nodekey);
-		if (rc == 0) {
-			/* Probably happens rarely, but first node on the page
-			 * was the one we wanted.
-			 */
-			mc->mc_ki[mc->mc_top] = 0;
-			if (exactp)
-				*exactp = 1;
-			goto set1;
-		}
-		if (rc > 0) {
-			unsigned int i;
-			unsigned int nkeys = NUMKEYS(mp);
-			if (nkeys > 1) {
-				if (mp->mp_flags & P_LEAF2) {
-					nodekey.mv_data = LEAF2KEY(mp,
-						 nkeys-1, nodekey.mv_size);
-				} else {
-					leaf = NODEPTR(mp, nkeys-1);
-					MDB_GET_KEY2(leaf, nodekey);
-				}
-				rc = mc->mc_dbx->md_cmp(key, &nodekey);
-				if (rc == 0) {
-					/* last node was the one we wanted */
-					mc->mc_ki[mc->mc_top] = nkeys-1;
-					if (exactp)
-						*exactp = 1;
-					goto set1;
-				}
-				if (rc < 0) {
-					if (mc->mc_ki[mc->mc_top] < NUMKEYS(mp)) {
-						/* This is definitely the right page, skip search_page */
-						if (mp->mp_flags & P_LEAF2) {
-							nodekey.mv_data = LEAF2KEY(mp,
-								 mc->mc_ki[mc->mc_top], nodekey.mv_size);
-						} else {
-							leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
-							MDB_GET_KEY2(leaf, nodekey);
-						}
-						rc = mc->mc_dbx->md_cmp(key, &nodekey);
-						if (rc == 0) {
-							/* current node was the one we wanted */
-							if (exactp)
-								*exactp = 1;
-							goto set1;
-						}
-					}
-					rc = 0;
-					goto set2;
-				}
-			}
-			/* If any parents have right-sibs, search.
-			 * Otherwise, there's nothing further.
-			 */
-			for (i=0; i<mc->mc_top; i++)
-				if (mc->mc_ki[i] <
-					NUMKEYS(mc->mc_pg[i])-1)
-					break;
-			if (i == mc->mc_top) {
-				/* There are no other pages */
-				mc->mc_ki[mc->mc_top] = nkeys;
-				return MDB_NOTFOUND;
-			}
-		}
-		if (!mc->mc_top) {
-			/* There are no other pages */
-			mc->mc_ki[mc->mc_top] = 0;
-			if (op == MDB_SET_RANGE && !exactp) {
-				rc = 0;
-				goto set1;
-			} else
-				return MDB_NOTFOUND;
-		}
-	} else {
-		mc->mc_pg[0] = 0;
-	}
-
-	rc = mdb_page_search(mc, key, 0);
-	if (rc != MDB_SUCCESS)
-		return rc;
-
-	mp = mc->mc_pg[mc->mc_top];
-	mdb_cassert(mc, IS_LEAF(mp));
-
-set2:
-	leaf = mdb_node_search(mc, key, exactp);
-	if (exactp != NULL && !*exactp) {
-		/* MDB_SET specified and not an exact match. */
-		return MDB_NOTFOUND;
-	}
-
-	if (leaf == NULL) {
-		DPUTS("===> inexact leaf not found, goto sibling");
-		if ((rc = mdb_cursor_sibling(mc, 1)) != MDB_SUCCESS) {
-			mc->mc_flags |= C_EOF;
-			return rc;		/* no entries matched */
-		}
-		mp = mc->mc_pg[mc->mc_top];
-		mdb_cassert(mc, IS_LEAF(mp));
-		leaf = NODEPTR(mp, 0);
-	}
-
-set1:
-	mc->mc_flags |= C_INITIALIZED;
-	mc->mc_flags &= ~C_EOF;
-
-	if (IS_LEAF2(mp)) {
-		if (op == MDB_SET_RANGE || op == MDB_SET_KEY) {
-			key->mv_size = mc->mc_db->md_pad;
-			key->mv_data = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], key->mv_size);
-		}
-		return MDB_SUCCESS;
-	}
-
-#ifdef MDB_VL32
-	if (mc->mc_xcursor && mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED) {
-		mdb_cursor_unref(&mc->mc_xcursor->mx_cursor);
-	}
-#endif
-	if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
-		mdb_xcursor_init1(mc, leaf);
-	}
-	if (data) {
-		if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
-			if (op == MDB_SET || op == MDB_SET_KEY || op == MDB_SET_RANGE) {
-				rc = mdb_cursor_first(&mc->mc_xcursor->mx_cursor, data, NULL);
-			} else {
-				int ex2, *ex2p;
-				if (op == MDB_GET_BOTH) {
-					ex2p = &ex2;
-					ex2 = 0;
-				} else {
-					ex2p = NULL;
-				}
-				rc = mdb_cursor_set(&mc->mc_xcursor->mx_cursor, data, NULL, MDB_SET_RANGE, ex2p);
-				if (rc != MDB_SUCCESS)
-					return rc;
-			}
-		} else if (op == MDB_GET_BOTH || op == MDB_GET_BOTH_RANGE) {
-			MDB_val olddata;
-			MDB_cmp_func *dcmp;
-			if ((rc = mdb_node_read(mc, leaf, &olddata)) != MDB_SUCCESS)
-				return rc;
-			dcmp = mc->mc_dbx->md_dcmp;
-#if UINT_MAX < SIZE_MAX || defined(MDB_VL32)
-			if (dcmp == mdb_cmp_int && olddata.mv_size == sizeof(mdb_size_t))
-				dcmp = mdb_cmp_clong;
-#endif
-			rc = dcmp(data, &olddata);
-			if (rc) {
-				if (op == MDB_GET_BOTH || rc > 0)
-					return MDB_NOTFOUND;
-				rc = 0;
-			}
-			*data = olddata;
-
-		} else {
-			if (mc->mc_xcursor)
-				mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);
-			if ((rc = mdb_node_read(mc, leaf, data)) != MDB_SUCCESS)
-				return rc;
-		}
-	}
-
-	/* The key already matches in all other cases */
-	if (op == MDB_SET_RANGE || op == MDB_SET_KEY)
-		MDB_GET_KEY(leaf, key);
-	DPRINTF(("==> cursor placed on key [%s]", DKEY(key)));
-
-	return rc;
-}
-
-/** Move the cursor to the first item in the database. */
-static int
-mdb_cursor_first(MDB_cursor *mc, MDB_val *key, MDB_val *data)
-{
-	int		 rc;
-	MDB_node	*leaf;
-
-	if (mc->mc_xcursor) {
-#ifdef MDB_VL32
-		if (mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED) {
-			mdb_cursor_unref(&mc->mc_xcursor->mx_cursor);
-		}
-#endif
-		mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);
-	}
-
-	if (!(mc->mc_flags & C_INITIALIZED) || mc->mc_top) {
-		rc = mdb_page_search(mc, NULL, MDB_PS_FIRST);
-		if (rc != MDB_SUCCESS)
-			return rc;
-	}
-	mdb_cassert(mc, IS_LEAF(mc->mc_pg[mc->mc_top]));
-
-	leaf = NODEPTR(mc->mc_pg[mc->mc_top], 0);
-	mc->mc_flags |= C_INITIALIZED;
-	mc->mc_flags &= ~C_EOF;
-
-	mc->mc_ki[mc->mc_top] = 0;
-
-	if (IS_LEAF2(mc->mc_pg[mc->mc_top])) {
-		key->mv_size = mc->mc_db->md_pad;
-		key->mv_data = LEAF2KEY(mc->mc_pg[mc->mc_top], 0, key->mv_size);
-		return MDB_SUCCESS;
-	}
-
-	if (data) {
-		if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
-			mdb_xcursor_init1(mc, leaf);
-			rc = mdb_cursor_first(&mc->mc_xcursor->mx_cursor, data, NULL);
-			if (rc)
-				return rc;
-		} else {
-			if ((rc = mdb_node_read(mc, leaf, data)) != MDB_SUCCESS)
-				return rc;
-		}
-	}
-	MDB_GET_KEY(leaf, key);
-	return MDB_SUCCESS;
-}
-
-/** Move the cursor to the last item in the database. */
-static int
-mdb_cursor_last(MDB_cursor *mc, MDB_val *key, MDB_val *data)
-{
-	int		 rc;
-	MDB_node	*leaf;
-
-	if (mc->mc_xcursor) {
-#ifdef MDB_VL32
-		if (mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED) {
-			mdb_cursor_unref(&mc->mc_xcursor->mx_cursor);
-		}
-#endif
-		mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);
-	}
-
-	if (!(mc->mc_flags & C_EOF)) {
-
-		if (!(mc->mc_flags & C_INITIALIZED) || mc->mc_top) {
-			rc = mdb_page_search(mc, NULL, MDB_PS_LAST);
-			if (rc != MDB_SUCCESS)
-				return rc;
-		}
-		mdb_cassert(mc, IS_LEAF(mc->mc_pg[mc->mc_top]));
-
-	}
-	mc->mc_ki[mc->mc_top] = NUMKEYS(mc->mc_pg[mc->mc_top]) - 1;
-	mc->mc_flags |= C_INITIALIZED|C_EOF;
-	leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
-
-	if (IS_LEAF2(mc->mc_pg[mc->mc_top])) {
-		key->mv_size = mc->mc_db->md_pad;
-		key->mv_data = LEAF2KEY(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top], key->mv_size);
-		return MDB_SUCCESS;
-	}
-
-	if (data) {
-		if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
-			mdb_xcursor_init1(mc, leaf);
-			rc = mdb_cursor_last(&mc->mc_xcursor->mx_cursor, data, NULL);
-			if (rc)
-				return rc;
-		} else {
-			if ((rc = mdb_node_read(mc, leaf, data)) != MDB_SUCCESS)
-				return rc;
-		}
-	}
-
-	MDB_GET_KEY(leaf, key);
-	return MDB_SUCCESS;
-}
-
-int
-mdb_cursor_get(MDB_cursor *mc, MDB_val *key, MDB_val *data,
-    MDB_cursor_op op)
-{
-	int		 rc;
-	int		 exact = 0;
-	int		 (*mfunc)(MDB_cursor *mc, MDB_val *key, MDB_val *data);
-
-	if (mc == NULL)
-		return EINVAL;
-
-	if (mc->mc_txn->mt_flags & MDB_TXN_BLOCKED)
-		return MDB_BAD_TXN;
-
-	switch (op) {
-	case MDB_GET_CURRENT:
-		if (!(mc->mc_flags & C_INITIALIZED)) {
-			rc = EINVAL;
-		} else {
-			MDB_page *mp = mc->mc_pg[mc->mc_top];
-			int nkeys = NUMKEYS(mp);
-			if (!nkeys || mc->mc_ki[mc->mc_top] >= nkeys) {
-				mc->mc_ki[mc->mc_top] = nkeys;
-				rc = MDB_NOTFOUND;
-				break;
-			}
-			rc = MDB_SUCCESS;
-			if (IS_LEAF2(mp)) {
-				key->mv_size = mc->mc_db->md_pad;
-				key->mv_data = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], key->mv_size);
-			} else {
-				MDB_node *leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
-				MDB_GET_KEY(leaf, key);
-				if (data) {
-					if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
-						rc = mdb_cursor_get(&mc->mc_xcursor->mx_cursor, data, NULL, MDB_GET_CURRENT);
-					} else {
-						rc = mdb_node_read(mc, leaf, data);
-					}
-				}
-			}
-		}
-		break;
-	case MDB_GET_BOTH:
-	case MDB_GET_BOTH_RANGE:
-		if (data == NULL) {
-			rc = EINVAL;
-			break;
-		}
-		if (mc->mc_xcursor == NULL) {
-			rc = MDB_INCOMPATIBLE;
-			break;
-		}
-		/* FALLTHRU */
-	case MDB_SET:
-	case MDB_SET_KEY:
-	case MDB_SET_RANGE:
-		if (key == NULL) {
-			rc = EINVAL;
-		} else {
-			rc = mdb_cursor_set(mc, key, data, op,
-				op == MDB_SET_RANGE ? NULL : &exact);
-		}
-		break;
-	case MDB_GET_MULTIPLE:
-		if (data == NULL || !(mc->mc_flags & C_INITIALIZED)) {
-			rc = EINVAL;
-			break;
-		}
-		if (!(mc->mc_db->md_flags & MDB_DUPFIXED)) {
-			rc = MDB_INCOMPATIBLE;
-			break;
-		}
-		rc = MDB_SUCCESS;
-		if (!(mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED) ||
-			(mc->mc_xcursor->mx_cursor.mc_flags & C_EOF))
-			break;
-		goto fetchm;
-	case MDB_NEXT_MULTIPLE:
-		if (data == NULL) {
-			rc = EINVAL;
-			break;
-		}
-		if (!(mc->mc_db->md_flags & MDB_DUPFIXED)) {
-			rc = MDB_INCOMPATIBLE;
-			break;
-		}
-		rc = mdb_cursor_next(mc, key, data, MDB_NEXT_DUP);
-		if (rc == MDB_SUCCESS) {
-			if (mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED) {
-				MDB_cursor *mx;
-fetchm:
-				mx = &mc->mc_xcursor->mx_cursor;
-				data->mv_size = NUMKEYS(mx->mc_pg[mx->mc_top]) *
-					mx->mc_db->md_pad;
-				data->mv_data = METADATA(mx->mc_pg[mx->mc_top]);
-				mx->mc_ki[mx->mc_top] = NUMKEYS(mx->mc_pg[mx->mc_top])-1;
-			} else {
-				rc = MDB_NOTFOUND;
-			}
-		}
-		break;
-	case MDB_PREV_MULTIPLE:
-		if (data == NULL) {
-			rc = EINVAL;
-			break;
-		}
-		if (!(mc->mc_db->md_flags & MDB_DUPFIXED)) {
-			rc = MDB_INCOMPATIBLE;
-			break;
-		}
-		if (!(mc->mc_flags & C_INITIALIZED))
-			rc = mdb_cursor_last(mc, key, data);
-		else
-			rc = MDB_SUCCESS;
-		if (rc == MDB_SUCCESS) {
-			MDB_cursor *mx = &mc->mc_xcursor->mx_cursor;
-			if (mx->mc_flags & C_INITIALIZED) {
-				rc = mdb_cursor_sibling(mx, 0);
-				if (rc == MDB_SUCCESS)
-					goto fetchm;
-			} else {
-				rc = MDB_NOTFOUND;
-			}
-		}
-		break;
-	case MDB_NEXT:
-	case MDB_NEXT_DUP:
-	case MDB_NEXT_NODUP:
-		rc = mdb_cursor_next(mc, key, data, op);
-		break;
-	case MDB_PREV:
-	case MDB_PREV_DUP:
-	case MDB_PREV_NODUP:
-		rc = mdb_cursor_prev(mc, key, data, op);
-		break;
-	case MDB_FIRST:
-		rc = mdb_cursor_first(mc, key, data);
-		break;
-	case MDB_FIRST_DUP:
-		mfunc = mdb_cursor_first;
-	mmove:
-		if (data == NULL || !(mc->mc_flags & C_INITIALIZED)) {
-			rc = EINVAL;
-			break;
-		}
-		if (mc->mc_xcursor == NULL) {
-			rc = MDB_INCOMPATIBLE;
-			break;
-		}
-		{
-			MDB_node *leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
-			if (!F_ISSET(leaf->mn_flags, F_DUPDATA)) {
-				MDB_GET_KEY(leaf, key);
-				rc = mdb_node_read(mc, leaf, data);
-				break;
-			}
-		}
-		if (!(mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED)) {
-			rc = EINVAL;
-			break;
-		}
-		rc = mfunc(&mc->mc_xcursor->mx_cursor, data, NULL);
-		break;
-	case MDB_LAST:
-		rc = mdb_cursor_last(mc, key, data);
-		break;
-	case MDB_LAST_DUP:
-		mfunc = mdb_cursor_last;
-		goto mmove;
-	default:
-		DPRINTF(("unhandled/unimplemented cursor operation %u", op));
-		rc = EINVAL;
-		break;
-	}
-
-	if (mc->mc_flags & C_DEL)
-		mc->mc_flags ^= C_DEL;
-
-	return rc;
-}
-
-/** Touch all the pages in the cursor stack. Set mc_top.
- *	Makes sure all the pages are writable, before attempting a write operation.
- * @param[in] mc The cursor to operate on.
- */
-static int
-mdb_cursor_touch(MDB_cursor *mc)
-{
-	int rc = MDB_SUCCESS;
-
-	if (mc->mc_dbi >= CORE_DBS && !(*mc->mc_dbflag & DB_DIRTY)) {
-		MDB_cursor mc2;
-		MDB_xcursor mcx;
-		if (TXN_DBI_CHANGED(mc->mc_txn, mc->mc_dbi))
-			return MDB_BAD_DBI;
-		mdb_cursor_init(&mc2, mc->mc_txn, MAIN_DBI, &mcx);
-		rc = mdb_page_search(&mc2, &mc->mc_dbx->md_name, MDB_PS_MODIFY);
-		if (rc)
-			 return rc;
-		*mc->mc_dbflag |= DB_DIRTY;
-	}
-	mc->mc_top = 0;
-	if (mc->mc_snum) {
-		do {
-			rc = mdb_page_touch(mc);
-		} while (!rc && ++(mc->mc_top) < mc->mc_snum);
-		mc->mc_top = mc->mc_snum-1;
-	}
-	return rc;
-}
-
-/** Do not spill pages to disk if txn is getting full, may fail instead */
-#define MDB_NOSPILL	0x8000
-
-int
-mdb_cursor_put(MDB_cursor *mc, MDB_val *key, MDB_val *data,
-    unsigned int flags)
-{
-	MDB_env		*env;
-	MDB_node	*leaf = NULL;
-	MDB_page	*fp, *mp, *sub_root = NULL;
-	uint16_t	fp_flags;
-	MDB_val		xdata, *rdata, dkey, olddata;
-	MDB_db dummy;
-	int do_sub = 0, insert_key, insert_data;
-	unsigned int mcount = 0, dcount = 0, nospill;
-	size_t nsize;
-	int rc, rc2;
-	unsigned int nflags;
-	DKBUF;
-
-	if (mc == NULL || key == NULL)
-		return EINVAL;
-
-	env = mc->mc_txn->mt_env;
-
-	/* Check this first so counter will always be zero on any
-	 * early failures.
-	 */
-	if (flags & MDB_MULTIPLE) {
-		dcount = data[1].mv_size;
-		data[1].mv_size = 0;
-		if (!F_ISSET(mc->mc_db->md_flags, MDB_DUPFIXED))
-			return MDB_INCOMPATIBLE;
-	}
-
-	nospill = flags & MDB_NOSPILL;
-	flags &= ~MDB_NOSPILL;
-
-	if (mc->mc_txn->mt_flags & (MDB_TXN_RDONLY|MDB_TXN_BLOCKED))
-		return (mc->mc_txn->mt_flags & MDB_TXN_RDONLY) ? EACCES : MDB_BAD_TXN;
-
-	if (key->mv_size-1 >= ENV_MAXKEY(env))
-		return MDB_BAD_VALSIZE;
-
-#if SIZE_MAX > MAXDATASIZE
-	if (data->mv_size > ((mc->mc_db->md_flags & MDB_DUPSORT) ? ENV_MAXKEY(env) : MAXDATASIZE))
-		return MDB_BAD_VALSIZE;
-#else
-	if ((mc->mc_db->md_flags & MDB_DUPSORT) && data->mv_size > ENV_MAXKEY(env))
-		return MDB_BAD_VALSIZE;
-#endif
-
-	DPRINTF(("==> put db %d key [%s], size %"Z"u, data size %"Z"u",
-		DDBI(mc), DKEY(key), key ? key->mv_size : 0, data->mv_size));
-
-	dkey.mv_size = 0;
-
-	if (flags == MDB_CURRENT) {
-		if (!(mc->mc_flags & C_INITIALIZED))
-			return EINVAL;
-		rc = MDB_SUCCESS;
-	} else if (mc->mc_db->md_root == P_INVALID) {
-		/* new database, cursor has nothing to point to */
-		mc->mc_snum = 0;
-		mc->mc_top = 0;
-		mc->mc_flags &= ~C_INITIALIZED;
-		rc = MDB_NO_ROOT;
-	} else {
-		int exact = 0;
-		MDB_val d2;
-		if (flags & MDB_APPEND) {
-			MDB_val k2;
-			rc = mdb_cursor_last(mc, &k2, &d2);
-			if (rc == 0) {
-				rc = mc->mc_dbx->md_cmp(key, &k2);
-				if (rc > 0) {
-					rc = MDB_NOTFOUND;
-					mc->mc_ki[mc->mc_top]++;
-				} else {
-					/* new key is <= last key */
-					rc = MDB_KEYEXIST;
-				}
-			}
-		} else {
-			rc = mdb_cursor_set(mc, key, &d2, MDB_SET, &exact);
-		}
-		if ((flags & MDB_NOOVERWRITE) && rc == 0) {
-			DPRINTF(("duplicate key [%s]", DKEY(key)));
-			*data = d2;
-			return MDB_KEYEXIST;
-		}
-		if (rc && rc != MDB_NOTFOUND)
-			return rc;
-	}
-
-	if (mc->mc_flags & C_DEL)
-		mc->mc_flags ^= C_DEL;
-
-	/* Cursor is positioned, check for room in the dirty list */
-	if (!nospill) {
-		if (flags & MDB_MULTIPLE) {
-			rdata = &xdata;
-			xdata.mv_size = data->mv_size * dcount;
-		} else {
-			rdata = data;
-		}
-		if ((rc2 = mdb_page_spill(mc, key, rdata)))
-			return rc2;
-	}
-
-	if (rc == MDB_NO_ROOT) {
-		MDB_page *np;
-		/* new database, write a root leaf page */
-		DPUTS("allocating new root leaf page");
-		if ((rc2 = mdb_page_new(mc, P_LEAF, 1, &np))) {
-			return rc2;
-		}
-		mdb_cursor_push(mc, np);
-		mc->mc_db->md_root = np->mp_pgno;
-		mc->mc_db->md_depth++;
-		*mc->mc_dbflag |= DB_DIRTY;
-		if ((mc->mc_db->md_flags & (MDB_DUPSORT|MDB_DUPFIXED))
-			== MDB_DUPFIXED)
-			np->mp_flags |= P_LEAF2;
-		mc->mc_flags |= C_INITIALIZED;
-	} else {
-		/* make sure all cursor pages are writable */
-		rc2 = mdb_cursor_touch(mc);
-		if (rc2)
-			return rc2;
-	}
-
-	insert_key = insert_data = rc;
-	if (insert_key) {
-		/* The key does not exist */
-		DPRINTF(("inserting key at index %i", mc->mc_ki[mc->mc_top]));
-		if ((mc->mc_db->md_flags & MDB_DUPSORT) &&
-			LEAFSIZE(key, data) > env->me_nodemax)
-		{
-			/* Too big for a node, insert in sub-DB.  Set up an empty
-			 * "old sub-page" for prep_subDB to expand to a full page.
-			 */
-			fp_flags = P_LEAF|P_DIRTY;
-			fp = env->me_pbuf;
-			fp->mp_pad = data->mv_size; /* used if MDB_DUPFIXED */
-			fp->mp_lower = fp->mp_upper = (PAGEHDRSZ-PAGEBASE);
-			olddata.mv_size = PAGEHDRSZ;
-			goto prep_subDB;
-		}
-	} else {
-		/* there's only a key anyway, so this is a no-op */
-		if (IS_LEAF2(mc->mc_pg[mc->mc_top])) {
-			char *ptr;
-			unsigned int ksize = mc->mc_db->md_pad;
-			if (key->mv_size != ksize)
-				return MDB_BAD_VALSIZE;
-			ptr = LEAF2KEY(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top], ksize);
-			memcpy(ptr, key->mv_data, ksize);
-fix_parent:
-			/* if overwriting slot 0 of leaf, need to
-			 * update branch key if there is a parent page
-			 */
-			if (mc->mc_top && !mc->mc_ki[mc->mc_top]) {
-				unsigned short dtop = 1;
-				mc->mc_top--;
-				/* slot 0 is always an empty key, find real slot */
-				while (mc->mc_top && !mc->mc_ki[mc->mc_top]) {
-					mc->mc_top--;
-					dtop++;
-				}
-				if (mc->mc_ki[mc->mc_top])
-					rc2 = mdb_update_key(mc, key);
-				else
-					rc2 = MDB_SUCCESS;
-				mc->mc_top += dtop;
-				if (rc2)
-					return rc2;
-			}
-			return MDB_SUCCESS;
-		}
-
-more:
-		leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
-		olddata.mv_size = NODEDSZ(leaf);
-		olddata.mv_data = NODEDATA(leaf);
-
-		/* DB has dups? */
-		if (F_ISSET(mc->mc_db->md_flags, MDB_DUPSORT)) {
-			/* Prepare (sub-)page/sub-DB to accept the new item,
-			 * if needed.  fp: old sub-page or a header faking
-			 * it.  mp: new (sub-)page.  offset: growth in page
-			 * size.  xdata: node data with new page or DB.
-			 */
-			unsigned	i, offset = 0;
-			mp = fp = xdata.mv_data = env->me_pbuf;
-			mp->mp_pgno = mc->mc_pg[mc->mc_top]->mp_pgno;
-
-			/* Was a single item before, must convert now */
-			if (!F_ISSET(leaf->mn_flags, F_DUPDATA)) {
-				MDB_cmp_func *dcmp;
-				/* Just overwrite the current item */
-				if (flags == MDB_CURRENT)
-					goto current;
-				dcmp = mc->mc_dbx->md_dcmp;
-#if UINT_MAX < SIZE_MAX || defined(MDB_VL32)
-				if (dcmp == mdb_cmp_int && olddata.mv_size == sizeof(mdb_size_t))
-					dcmp = mdb_cmp_clong;
-#endif
-				/* does data match? */
-				if (!dcmp(data, &olddata)) {
-					if (flags & (MDB_NODUPDATA|MDB_APPENDDUP))
-						return MDB_KEYEXIST;
-					/* overwrite it */
-					goto current;
-				}
-
-				/* Back up original data item */
-				dkey.mv_size = olddata.mv_size;
-				dkey.mv_data = memcpy(fp+1, olddata.mv_data, olddata.mv_size);
-
-				/* Make sub-page header for the dup items, with dummy body */
-				fp->mp_flags = P_LEAF|P_DIRTY|P_SUBP;
-				fp->mp_lower = (PAGEHDRSZ-PAGEBASE);
-				xdata.mv_size = PAGEHDRSZ + dkey.mv_size + data->mv_size;
-				if (mc->mc_db->md_flags & MDB_DUPFIXED) {
-					fp->mp_flags |= P_LEAF2;
-					fp->mp_pad = data->mv_size;
-					xdata.mv_size += 2 * data->mv_size;	/* leave space for 2 more */
-				} else {
-					xdata.mv_size += 2 * (sizeof(indx_t) + NODESIZE) +
-						(dkey.mv_size & 1) + (data->mv_size & 1);
-				}
-				fp->mp_upper = xdata.mv_size - PAGEBASE;
-				olddata.mv_size = xdata.mv_size; /* pretend olddata is fp */
-			} else if (leaf->mn_flags & F_SUBDATA) {
-				/* Data is on sub-DB, just store it */
-				flags |= F_DUPDATA|F_SUBDATA;
-				goto put_sub;
-			} else {
-				/* Data is on sub-page */
-				fp = olddata.mv_data;
-				switch (flags) {
-				default:
-					if (!(mc->mc_db->md_flags & MDB_DUPFIXED)) {
-						offset = EVEN(NODESIZE + sizeof(indx_t) +
-							data->mv_size);
-						break;
-					}
-					offset = fp->mp_pad;
-					if (SIZELEFT(fp) < offset) {
-						offset *= 4; /* space for 4 more */
-						break;
-					}
-					/* FALLTHRU: Big enough MDB_DUPFIXED sub-page */
-				case MDB_CURRENT:
-					fp->mp_flags |= P_DIRTY;
-					COPY_PGNO(fp->mp_pgno, mp->mp_pgno);
-					mc->mc_xcursor->mx_cursor.mc_pg[0] = fp;
-					flags |= F_DUPDATA;
-					goto put_sub;
-				}
-				xdata.mv_size = olddata.mv_size + offset;
-			}
-
-			fp_flags = fp->mp_flags;
-			if (NODESIZE + NODEKSZ(leaf) + xdata.mv_size > env->me_nodemax) {
-					/* Too big for a sub-page, convert to sub-DB */
-					fp_flags &= ~P_SUBP;
-prep_subDB:
-					if (mc->mc_db->md_flags & MDB_DUPFIXED) {
-						fp_flags |= P_LEAF2;
-						dummy.md_pad = fp->mp_pad;
-						dummy.md_flags = MDB_DUPFIXED;
-						if (mc->mc_db->md_flags & MDB_INTEGERDUP)
-							dummy.md_flags |= MDB_INTEGERKEY;
-					} else {
-						dummy.md_pad = 0;
-						dummy.md_flags = 0;
-					}
-					dummy.md_depth = 1;
-					dummy.md_branch_pages = 0;
-					dummy.md_leaf_pages = 1;
-					dummy.md_overflow_pages = 0;
-					dummy.md_entries = NUMKEYS(fp);
-					xdata.mv_size = sizeof(MDB_db);
-					xdata.mv_data = &dummy;
-					if ((rc = mdb_page_alloc(mc, 1, &mp)))
-						return rc;
-					offset = env->me_psize - olddata.mv_size;
-					flags |= F_DUPDATA|F_SUBDATA;
-					dummy.md_root = mp->mp_pgno;
-					sub_root = mp;
-			}
-			if (mp != fp) {
-				mp->mp_flags = fp_flags | P_DIRTY;
-				mp->mp_pad   = fp->mp_pad;
-				mp->mp_lower = fp->mp_lower;
-				mp->mp_upper = fp->mp_upper + offset;
-				if (fp_flags & P_LEAF2) {
-					memcpy(METADATA(mp), METADATA(fp), NUMKEYS(fp) * fp->mp_pad);
-				} else {
-					memcpy((char *)mp + mp->mp_upper + PAGEBASE, (char *)fp + fp->mp_upper + PAGEBASE,
-						olddata.mv_size - fp->mp_upper - PAGEBASE);
-					for (i=0; i<NUMKEYS(fp); i++)
-						mp->mp_ptrs[i] = fp->mp_ptrs[i] + offset;
-				}
-			}
-
-			rdata = &xdata;
-			flags |= F_DUPDATA;
-			do_sub = 1;
-			if (!insert_key)
-				mdb_node_del(mc, 0);
-			goto new_sub;
-		}
-current:
-		/* LMDB passes F_SUBDATA in 'flags' to write a DB record */
-		if ((leaf->mn_flags ^ flags) & F_SUBDATA)
-			return MDB_INCOMPATIBLE;
-		/* overflow page overwrites need special handling */
-		if (F_ISSET(leaf->mn_flags, F_BIGDATA)) {
-			MDB_page *omp;
-			pgno_t pg;
-			int level, ovpages, dpages = OVPAGES(data->mv_size, env->me_psize);
-
-			memcpy(&pg, olddata.mv_data, sizeof(pg));
-			if ((rc2 = mdb_page_get(mc, pg, &omp, &level)) != 0)
-				return rc2;
-			ovpages = omp->mp_pages;
-
-			/* Is the ov page large enough? */
-			if (ovpages >= dpages) {
-			  if (!(omp->mp_flags & P_DIRTY) &&
-				  (level || (env->me_flags & MDB_WRITEMAP)))
-			  {
-				rc = mdb_page_unspill(mc->mc_txn, omp, &omp);
-				if (rc)
-					return rc;
-				level = 0;		/* dirty in this txn or clean */
-			  }
-			  /* Is it dirty? */
-			  if (omp->mp_flags & P_DIRTY) {
-				/* yes, overwrite it. Note in this case we don't
-				 * bother to try shrinking the page if the new data
-				 * is smaller than the overflow threshold.
-				 */
-				if (level > 1) {
-					/* It is writable only in a parent txn */
-					size_t sz = (size_t) env->me_psize * ovpages, off;
-					MDB_page *np = mdb_page_malloc(mc->mc_txn, ovpages);
-					MDB_ID2 id2;
-					if (!np)
-						return ENOMEM;
-					id2.mid = pg;
-					id2.mptr = np;
-					/* Note - this page is already counted in parent's dirty_room */
-					rc2 = mdb_mid2l_insert(mc->mc_txn->mt_u.dirty_list, &id2);
-					mdb_cassert(mc, rc2 == 0);
-					if (!(flags & MDB_RESERVE)) {
-						/* Copy end of page, adjusting alignment so
-						 * compiler may copy words instead of bytes.
-						 */
-						off = (PAGEHDRSZ + data->mv_size) & -sizeof(size_t);
-						memcpy((size_t *)((char *)np + off),
-							(size_t *)((char *)omp + off), sz - off);
-						sz = PAGEHDRSZ;
-					}
-					memcpy(np, omp, sz); /* Copy beginning of page */
-					omp = np;
-				}
-				SETDSZ(leaf, data->mv_size);
-				if (F_ISSET(flags, MDB_RESERVE))
-					data->mv_data = METADATA(omp);
-				else
-					memcpy(METADATA(omp), data->mv_data, data->mv_size);
-				return MDB_SUCCESS;
-			  }
-			}
-			if ((rc2 = mdb_ovpage_free(mc, omp)) != MDB_SUCCESS)
-				return rc2;
-		} else if (data->mv_size == olddata.mv_size) {
-			/* same size, just replace it. Note that we could
-			 * also reuse this node if the new data is smaller,
-			 * but instead we opt to shrink the node in that case.
-			 */
-			if (F_ISSET(flags, MDB_RESERVE))
-				data->mv_data = olddata.mv_data;
-			else if (!(mc->mc_flags & C_SUB))
-				memcpy(olddata.mv_data, data->mv_data, data->mv_size);
-			else {
-				memcpy(NODEKEY(leaf), key->mv_data, key->mv_size);
-				goto fix_parent;
-			}
-			return MDB_SUCCESS;
-		}
-		mdb_node_del(mc, 0);
-	}
-
-	rdata = data;
-
-new_sub:
-	nflags = flags & NODE_ADD_FLAGS;
-	nsize = IS_LEAF2(mc->mc_pg[mc->mc_top]) ? key->mv_size : mdb_leaf_size(env, key, rdata);
-	if (SIZELEFT(mc->mc_pg[mc->mc_top]) < nsize) {
-		if (( flags & (F_DUPDATA|F_SUBDATA)) == F_DUPDATA )
-			nflags &= ~MDB_APPEND; /* sub-page may need room to grow */
-		if (!insert_key)
-			nflags |= MDB_SPLIT_REPLACE;
-		rc = mdb_page_split(mc, key, rdata, P_INVALID, nflags);
-	} else {
-		/* There is room already in this leaf page. */
-		rc = mdb_node_add(mc, mc->mc_ki[mc->mc_top], key, rdata, 0, nflags);
-		if (rc == 0) {
-			/* Adjust other cursors pointing to mp */
-			MDB_cursor *m2, *m3;
-			MDB_dbi dbi = mc->mc_dbi;
-			unsigned i = mc->mc_top;
-			MDB_page *mp = mc->mc_pg[i];
-
-			for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
-				if (mc->mc_flags & C_SUB)
-					m3 = &m2->mc_xcursor->mx_cursor;
-				else
-					m3 = m2;
-				if (m3 == mc || m3->mc_snum < mc->mc_snum || m3->mc_pg[i] != mp) continue;
-				if (m3->mc_ki[i] >= mc->mc_ki[i] && insert_key) {
-					m3->mc_ki[i]++;
-				}
-				if (m3->mc_xcursor && (m3->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED)) {
-					MDB_node *n2 = NODEPTR(mp, m3->mc_ki[i]);
-					if ((n2->mn_flags & (F_SUBDATA|F_DUPDATA)) == F_DUPDATA)
-						m3->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(n2);
-				}
-			}
-		}
-	}
-
-	if (rc == MDB_SUCCESS) {
-		/* Now store the actual data in the child DB. Note that we're
-		 * storing the user data in the keys field, so there are strict
-		 * size limits on dupdata. The actual data fields of the child
-		 * DB are all zero size.
-		 */
-		if (do_sub) {
-			int xflags, new_dupdata;
-			mdb_size_t ecount;
-put_sub:
-			xdata.mv_size = 0;
-			xdata.mv_data = "";
-			leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
-			if (flags & MDB_CURRENT) {
-				xflags = MDB_CURRENT|MDB_NOSPILL;
-			} else {
-				mdb_xcursor_init1(mc, leaf);
-				xflags = (flags & MDB_NODUPDATA) ?
-					MDB_NOOVERWRITE|MDB_NOSPILL : MDB_NOSPILL;
-			}
-			if (sub_root)
-				mc->mc_xcursor->mx_cursor.mc_pg[0] = sub_root;
-			new_dupdata = (int)dkey.mv_size;
-			/* converted, write the original data first */
-			if (dkey.mv_size) {
-				rc = mdb_cursor_put(&mc->mc_xcursor->mx_cursor, &dkey, &xdata, xflags);
-				if (rc)
-					goto bad_sub;
-				/* we've done our job */
-				dkey.mv_size = 0;
-			}
-			if (!(leaf->mn_flags & F_SUBDATA) || sub_root) {
-				/* Adjust other cursors pointing to mp */
-				MDB_cursor *m2;
-				MDB_xcursor *mx = mc->mc_xcursor;
-				unsigned i = mc->mc_top;
-				MDB_page *mp = mc->mc_pg[i];
-				int nkeys = NUMKEYS(mp);
-
-				for (m2 = mc->mc_txn->mt_cursors[mc->mc_dbi]; m2; m2=m2->mc_next) {
-					if (m2 == mc || m2->mc_snum < mc->mc_snum) continue;
-					if (!(m2->mc_flags & C_INITIALIZED)) continue;
-					if (m2->mc_pg[i] == mp) {
-						if (m2->mc_ki[i] == mc->mc_ki[i]) {
-							mdb_xcursor_init2(m2, mx, new_dupdata);
-						} else if (!insert_key && m2->mc_ki[i] < nkeys) {
-							MDB_node *n2 = NODEPTR(mp, m2->mc_ki[i]);
-							if ((n2->mn_flags & (F_SUBDATA|F_DUPDATA)) == F_DUPDATA)
-								m2->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(n2);
-						}
-					}
-				}
-			}
-			ecount = mc->mc_xcursor->mx_db.md_entries;
-			if (flags & MDB_APPENDDUP)
-				xflags |= MDB_APPEND;
-			rc = mdb_cursor_put(&mc->mc_xcursor->mx_cursor, data, &xdata, xflags);
-			if (flags & F_SUBDATA) {
-				void *db = NODEDATA(leaf);
-				memcpy(db, &mc->mc_xcursor->mx_db, sizeof(MDB_db));
-			}
-			insert_data = mc->mc_xcursor->mx_db.md_entries - ecount;
-		}
-		/* Increment count unless we just replaced an existing item. */
-		if (insert_data)
-			mc->mc_db->md_entries++;
-		if (insert_key) {
-			/* Invalidate txn if we created an empty sub-DB */
-			if (rc)
-				goto bad_sub;
-			/* If we succeeded and the key didn't exist before,
-			 * make sure the cursor is marked valid.
-			 */
-			mc->mc_flags |= C_INITIALIZED;
-		}
-		if (flags & MDB_MULTIPLE) {
-			if (!rc) {
-				mcount++;
-				/* let caller know how many succeeded, if any */
-				data[1].mv_size = mcount;
-				if (mcount < dcount) {
-					data[0].mv_data = (char *)data[0].mv_data + data[0].mv_size;
-					insert_key = insert_data = 0;
-					goto more;
-				}
-			}
-		}
-		return rc;
-bad_sub:
-		if (rc == MDB_KEYEXIST)	/* should not happen, we deleted that item */
-			rc = MDB_CORRUPTED;
-	}
-	mc->mc_txn->mt_flags |= MDB_TXN_ERROR;
-	return rc;
-}
-
-int
-mdb_cursor_del(MDB_cursor *mc, unsigned int flags)
-{
-	MDB_node	*leaf;
-	MDB_page	*mp;
-	int rc;
-
-	if (mc->mc_txn->mt_flags & (MDB_TXN_RDONLY|MDB_TXN_BLOCKED))
-		return (mc->mc_txn->mt_flags & MDB_TXN_RDONLY) ? EACCES : MDB_BAD_TXN;
-
-	if (!(mc->mc_flags & C_INITIALIZED))
-		return EINVAL;
-
-	if (mc->mc_ki[mc->mc_top] >= NUMKEYS(mc->mc_pg[mc->mc_top]))
-		return MDB_NOTFOUND;
-
-	if (!(flags & MDB_NOSPILL) && (rc = mdb_page_spill(mc, NULL, NULL)))
-		return rc;
-
-	rc = mdb_cursor_touch(mc);
-	if (rc)
-		return rc;
-
-	mp = mc->mc_pg[mc->mc_top];
-	if (IS_LEAF2(mp))
-		goto del_key;
-	leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
-
-	if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
-		if (flags & MDB_NODUPDATA) {
-			/* mdb_cursor_del0() will subtract the final entry */
-			mc->mc_db->md_entries -= mc->mc_xcursor->mx_db.md_entries - 1;
-			mc->mc_xcursor->mx_cursor.mc_flags &= ~C_INITIALIZED;
-		} else {
-			if (!F_ISSET(leaf->mn_flags, F_SUBDATA)) {
-				mc->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(leaf);
-			}
-			rc = mdb_cursor_del(&mc->mc_xcursor->mx_cursor, MDB_NOSPILL);
-			if (rc)
-				return rc;
-			/* If sub-DB still has entries, we're done */
-			if (mc->mc_xcursor->mx_db.md_entries) {
-				if (leaf->mn_flags & F_SUBDATA) {
-					/* update subDB info */
-					void *db = NODEDATA(leaf);
-					memcpy(db, &mc->mc_xcursor->mx_db, sizeof(MDB_db));
-				} else {
-					MDB_cursor *m2;
-					/* shrink fake page */
-					mdb_node_shrink(mp, mc->mc_ki[mc->mc_top]);
-					leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
-					mc->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(leaf);
-					/* fix other sub-DB cursors pointed at fake pages on this page */
-					for (m2 = mc->mc_txn->mt_cursors[mc->mc_dbi]; m2; m2=m2->mc_next) {
-						if (m2 == mc || m2->mc_snum < mc->mc_snum) continue;
-						if (!(m2->mc_flags & C_INITIALIZED)) continue;
-						if (m2->mc_pg[mc->mc_top] == mp) {
-							if (m2->mc_ki[mc->mc_top] == mc->mc_ki[mc->mc_top]) {
-								m2->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(leaf);
-							} else {
-								MDB_node *n2 = NODEPTR(mp, m2->mc_ki[mc->mc_top]);
-								if (!(n2->mn_flags & F_SUBDATA))
-									m2->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(n2);
-							}
-						}
-					}
-				}
-				mc->mc_db->md_entries--;
-				return rc;
-			} else {
-				mc->mc_xcursor->mx_cursor.mc_flags &= ~C_INITIALIZED;
-			}
-			/* otherwise fall thru and delete the sub-DB */
-		}
-
-		if (leaf->mn_flags & F_SUBDATA) {
-			/* add all the child DB's pages to the free list */
-			rc = mdb_drop0(&mc->mc_xcursor->mx_cursor, 0);
-			if (rc)
-				goto fail;
-		}
-	}
-	/* LMDB passes F_SUBDATA in 'flags' to delete a DB record */
-	else if ((leaf->mn_flags ^ flags) & F_SUBDATA) {
-		rc = MDB_INCOMPATIBLE;
-		goto fail;
-	}
-
-	/* add overflow pages to free list */
-	if (F_ISSET(leaf->mn_flags, F_BIGDATA)) {
-		MDB_page *omp;
-		pgno_t pg;
-
-		memcpy(&pg, NODEDATA(leaf), sizeof(pg));
-		if ((rc = mdb_page_get(mc, pg, &omp, NULL)) ||
-			(rc = mdb_ovpage_free(mc, omp)))
-			goto fail;
-	}
-
-del_key:
-	return mdb_cursor_del0(mc);
-
-fail:
-	mc->mc_txn->mt_flags |= MDB_TXN_ERROR;
-	return rc;
-}
-
-/** Allocate and initialize new pages for a database.
- * @param[in] mc a cursor on the database being added to.
- * @param[in] flags flags defining what type of page is being allocated.
- * @param[in] num the number of pages to allocate. This is usually 1,
- * unless allocating overflow pages for a large record.
- * @param[out] mp Address of a page, or NULL on failure.
- * @return 0 on success, non-zero on failure.
- */
-static int
-mdb_page_new(MDB_cursor *mc, uint32_t flags, int num, MDB_page **mp)
-{
-	MDB_page	*np;
-	int rc;
-
-	if ((rc = mdb_page_alloc(mc, num, &np)))
-		return rc;
-	DPRINTF(("allocated new mpage %"Y"u, page size %u",
-	    np->mp_pgno, mc->mc_txn->mt_env->me_psize));
-	np->mp_flags = flags | P_DIRTY;
-	np->mp_lower = (PAGEHDRSZ-PAGEBASE);
-	np->mp_upper = mc->mc_txn->mt_env->me_psize - PAGEBASE;
-
-	if (IS_BRANCH(np))
-		mc->mc_db->md_branch_pages++;
-	else if (IS_LEAF(np))
-		mc->mc_db->md_leaf_pages++;
-	else if (IS_OVERFLOW(np)) {
-		mc->mc_db->md_overflow_pages += num;
-		np->mp_pages = num;
-	}
-	*mp = np;
-
-	return 0;
-}
-
-/** Calculate the size of a leaf node.
- * The size depends on the environment's page size; if a data item
- * is too large it will be put onto an overflow page and the node
- * size will only include the key and not the data. Sizes are always
- * rounded up to an even number of bytes, to guarantee 2-byte alignment
- * of the #MDB_node headers.
- * @param[in] env The environment handle.
- * @param[in] key The key for the node.
- * @param[in] data The data for the node.
- * @return The number of bytes needed to store the node.
- */
-static size_t
-mdb_leaf_size(MDB_env *env, MDB_val *key, MDB_val *data)
-{
-	size_t		 sz;
-
-	sz = LEAFSIZE(key, data);
-	if (sz > env->me_nodemax) {
-		/* put on overflow page */
-		sz -= data->mv_size - sizeof(pgno_t);
-	}
-
-	return EVEN(sz + sizeof(indx_t));
-}
-
-/** Calculate the size of a branch node.
- * The size should depend on the environment's page size but since
- * we currently don't support spilling large keys onto overflow
- * pages, it's simply the size of the #MDB_node header plus the
- * size of the key. Sizes are always rounded up to an even number
- * of bytes, to guarantee 2-byte alignment of the #MDB_node headers.
- * @param[in] env The environment handle.
- * @param[in] key The key for the node.
- * @return The number of bytes needed to store the node.
- */
-static size_t
-mdb_branch_size(MDB_env *env, MDB_val *key)
-{
-	size_t		 sz;
-
-	sz = INDXSIZE(key);
-	if (sz > env->me_nodemax) {
-		/* put on overflow page */
-		/* not implemented */
-		/* sz -= key->size - sizeof(pgno_t); */
-	}
-
-	return sz + sizeof(indx_t);
-}
-
-/** Add a node to the page pointed to by the cursor.
- * @param[in] mc The cursor for this operation.
- * @param[in] indx The index on the page where the new node should be added.
- * @param[in] key The key for the new node.
- * @param[in] data The data for the new node, if any.
- * @param[in] pgno The page number, if adding a branch node.
- * @param[in] flags Flags for the node.
- * @return 0 on success, non-zero on failure. Possible errors are:
- * <ul>
- *	<li>ENOMEM - failed to allocate overflow pages for the node.
- *	<li>MDB_PAGE_FULL - there is insufficient room in the page. This error
- *	should never happen since all callers already calculate the
- *	page's free space before calling this function.
- * </ul>
- */
-static int
-mdb_node_add(MDB_cursor *mc, indx_t indx,
-    MDB_val *key, MDB_val *data, pgno_t pgno, unsigned int flags)
-{
-	unsigned int	 i;
-	size_t		 node_size = NODESIZE;
-	ssize_t		 room;
-	indx_t		 ofs;
-	MDB_node	*node;
-	MDB_page	*mp = mc->mc_pg[mc->mc_top];
-	MDB_page	*ofp = NULL;		/* overflow page */
-	void		*ndata;
-	DKBUF;
-
-	mdb_cassert(mc, mp->mp_upper >= mp->mp_lower);
-
-	DPRINTF(("add to %s %spage %"Y"u index %i, data size %"Z"u key size %"Z"u [%s]",
-	    IS_LEAF(mp) ? "leaf" : "branch",
-		IS_SUBP(mp) ? "sub-" : "",
-		mdb_dbg_pgno(mp), indx, data ? data->mv_size : 0,
-		key ? key->mv_size : 0, key ? DKEY(key) : "null"));
-
-	if (IS_LEAF2(mp)) {
-		/* Move higher keys up one slot. */
-		int ksize = mc->mc_db->md_pad, dif;
-		char *ptr = LEAF2KEY(mp, indx, ksize);
-		dif = NUMKEYS(mp) - indx;
-		if (dif > 0)
-			memmove(ptr+ksize, ptr, dif*ksize);
-		/* insert new key */
-		memcpy(ptr, key->mv_data, ksize);
-
-		/* Just using these for counting */
-		mp->mp_lower += sizeof(indx_t);
-		mp->mp_upper -= ksize - sizeof(indx_t);
-		return MDB_SUCCESS;
-	}
-
-	room = (ssize_t)SIZELEFT(mp) - (ssize_t)sizeof(indx_t);
-	if (key != NULL)
-		node_size += key->mv_size;
-	if (IS_LEAF(mp)) {
-		mdb_cassert(mc, key && data);
-		if (F_ISSET(flags, F_BIGDATA)) {
-			/* Data already on overflow page. */
-			node_size += sizeof(pgno_t);
-		} else if (node_size + data->mv_size > mc->mc_txn->mt_env->me_nodemax) {
-			int ovpages = OVPAGES(data->mv_size, mc->mc_txn->mt_env->me_psize);
-			int rc;
-			/* Put data on overflow page. */
-			DPRINTF(("data size is %"Z"u, node would be %"Z"u, put data on overflow page",
-			    data->mv_size, node_size+data->mv_size));
-			node_size = EVEN(node_size + sizeof(pgno_t));
-			if ((ssize_t)node_size > room)
-				goto full;
-			if ((rc = mdb_page_new(mc, P_OVERFLOW, ovpages, &ofp)))
-				return rc;
-			DPRINTF(("allocated overflow page %"Y"u", ofp->mp_pgno));
-			flags |= F_BIGDATA;
-			goto update;
-		} else {
-			node_size += data->mv_size;
-		}
-	}
-	node_size = EVEN(node_size);
-	if ((ssize_t)node_size > room)
-		goto full;
-
-update:
-	/* Move higher pointers up one slot. */
-	for (i = NUMKEYS(mp); i > indx; i--)
-		mp->mp_ptrs[i] = mp->mp_ptrs[i - 1];
-
-	/* Adjust free space offsets. */
-	ofs = mp->mp_upper - node_size;
-	mdb_cassert(mc, ofs >= mp->mp_lower + sizeof(indx_t));
-	mp->mp_ptrs[indx] = ofs;
-	mp->mp_upper = ofs;
-	mp->mp_lower += sizeof(indx_t);
-
-	/* Write the node data. */
-	node = NODEPTR(mp, indx);
-	node->mn_ksize = (key == NULL) ? 0 : key->mv_size;
-	node->mn_flags = flags;
-	if (IS_LEAF(mp))
-		SETDSZ(node,data->mv_size);
-	else
-		SETPGNO(node,pgno);
-
-	if (key)
-		memcpy(NODEKEY(node), key->mv_data, key->mv_size);
-
-	if (IS_LEAF(mp)) {
-		ndata = NODEDATA(node);
-		if (ofp == NULL) {
-			if (F_ISSET(flags, F_BIGDATA))
-				memcpy(ndata, data->mv_data, sizeof(pgno_t));
-			else if (F_ISSET(flags, MDB_RESERVE))
-				data->mv_data = ndata;
-			else
-				memcpy(ndata, data->mv_data, data->mv_size);
-		} else {
-			memcpy(ndata, &ofp->mp_pgno, sizeof(pgno_t));
-			ndata = METADATA(ofp);
-			if (F_ISSET(flags, MDB_RESERVE))
-				data->mv_data = ndata;
-			else
-				memcpy(ndata, data->mv_data, data->mv_size);
-		}
-	}
-
-	return MDB_SUCCESS;
-
-full:
-	DPRINTF(("not enough room in page %"Y"u, got %u ptrs",
-		mdb_dbg_pgno(mp), NUMKEYS(mp)));
-	DPRINTF(("upper-lower = %u - %u = %"Z"d", mp->mp_upper,mp->mp_lower,room));
-	DPRINTF(("node size = %"Z"u", node_size));
-	mc->mc_txn->mt_flags |= MDB_TXN_ERROR;
-	return MDB_PAGE_FULL;
-}
-
-/** Delete the specified node from a page.
- * @param[in] mc Cursor pointing to the node to delete.
- * @param[in] ksize The size of a node. Only used if the page is
- * part of a #MDB_DUPFIXED database.
- */
-static void
-mdb_node_del(MDB_cursor *mc, int ksize)
-{
-	MDB_page *mp = mc->mc_pg[mc->mc_top];
-	indx_t	indx = mc->mc_ki[mc->mc_top];
-	unsigned int	 sz;
-	indx_t		 i, j, numkeys, ptr;
-	MDB_node	*node;
-	char		*base;
-
-	DPRINTF(("delete node %u on %s page %"Y"u", indx,
-	    IS_LEAF(mp) ? "leaf" : "branch", mdb_dbg_pgno(mp)));
-	numkeys = NUMKEYS(mp);
-	mdb_cassert(mc, indx < numkeys);
-
-	if (IS_LEAF2(mp)) {
-		int x = numkeys - 1 - indx;
-		base = LEAF2KEY(mp, indx, ksize);
-		if (x)
-			memmove(base, base + ksize, x * ksize);
-		mp->mp_lower -= sizeof(indx_t);
-		mp->mp_upper += ksize - sizeof(indx_t);
-		return;
-	}
-
-	node = NODEPTR(mp, indx);
-	sz = NODESIZE + node->mn_ksize;
-	if (IS_LEAF(mp)) {
-		if (F_ISSET(node->mn_flags, F_BIGDATA))
-			sz += sizeof(pgno_t);
-		else
-			sz += NODEDSZ(node);
-	}
-	sz = EVEN(sz);
-
-	ptr = mp->mp_ptrs[indx];
-	for (i = j = 0; i < numkeys; i++) {
-		if (i != indx) {
-			mp->mp_ptrs[j] = mp->mp_ptrs[i];
-			if (mp->mp_ptrs[i] < ptr)
-				mp->mp_ptrs[j] += sz;
-			j++;
-		}
-	}
-
-	base = (char *)mp + mp->mp_upper + PAGEBASE;
-	memmove(base + sz, base, ptr - mp->mp_upper);
-
-	mp->mp_lower -= sizeof(indx_t);
-	mp->mp_upper += sz;
-}
-
-/** Compact the main page after deleting a node on a subpage.
- * @param[in] mp The main page to operate on.
- * @param[in] indx The index of the subpage on the main page.
- */
-static void
-mdb_node_shrink(MDB_page *mp, indx_t indx)
-{
-	MDB_node *node;
-	MDB_page *sp, *xp;
-	char *base;
-	indx_t delta, nsize, len, ptr;
-	int i;
-
-	node = NODEPTR(mp, indx);
-	sp = (MDB_page *)NODEDATA(node);
-	delta = SIZELEFT(sp);
-	nsize = NODEDSZ(node) - delta;
-
-	/* Prepare to shift upward, set len = length(subpage part to shift) */
-	if (IS_LEAF2(sp)) {
-		len = nsize;
-		if (nsize & 1)
-			return;		/* do not make the node uneven-sized */
-	} else {
-		xp = (MDB_page *)((char *)sp + delta); /* destination subpage */
-		for (i = NUMKEYS(sp); --i >= 0; )
-			xp->mp_ptrs[i] = sp->mp_ptrs[i] - delta;
-		len = PAGEHDRSZ;
-	}
-	sp->mp_upper = sp->mp_lower;
-	COPY_PGNO(sp->mp_pgno, mp->mp_pgno);
-	SETDSZ(node, nsize);
-
-	/* Shift <lower nodes...initial part of subpage> upward */
-	base = (char *)mp + mp->mp_upper + PAGEBASE;
-	memmove(base + delta, base, (char *)sp + len - base);
-
-	ptr = mp->mp_ptrs[indx];
-	for (i = NUMKEYS(mp); --i >= 0; ) {
-		if (mp->mp_ptrs[i] <= ptr)
-			mp->mp_ptrs[i] += delta;
-	}
-	mp->mp_upper += delta;
-}
-
-/** Initial setup of a sorted-dups cursor.
- * Sorted duplicates are implemented as a sub-database for the given key.
- * The duplicate data items are actually keys of the sub-database.
- * Operations on the duplicate data items are performed using a sub-cursor
- * initialized when the sub-database is first accessed. This function does
- * the preliminary setup of the sub-cursor, filling in the fields that
- * depend only on the parent DB.
- * @param[in] mc The main cursor whose sorted-dups cursor is to be initialized.
- */
-static void
-mdb_xcursor_init0(MDB_cursor *mc)
-{
-	MDB_xcursor *mx = mc->mc_xcursor;
-
-	mx->mx_cursor.mc_xcursor = NULL;
-	mx->mx_cursor.mc_txn = mc->mc_txn;
-	mx->mx_cursor.mc_db = &mx->mx_db;
-	mx->mx_cursor.mc_dbx = &mx->mx_dbx;
-	mx->mx_cursor.mc_dbi = mc->mc_dbi;
-	mx->mx_cursor.mc_dbflag = &mx->mx_dbflag;
-	mx->mx_cursor.mc_snum = 0;
-	mx->mx_cursor.mc_top = 0;
-#ifdef MDB_VL32
-	mx->mx_cursor.mc_ovpg = 0;
-#endif
-	mx->mx_cursor.mc_flags = C_SUB | (mc->mc_flags & (C_ORIG_RDONLY|C_WRITEMAP));
-	mx->mx_dbx.md_name.mv_size = 0;
-	mx->mx_dbx.md_name.mv_data = NULL;
-	mx->mx_dbx.md_cmp = mc->mc_dbx->md_dcmp;
-	mx->mx_dbx.md_dcmp = NULL;
-	mx->mx_dbx.md_rel = mc->mc_dbx->md_rel;
-}
-
-/** Final setup of a sorted-dups cursor.
- *	Sets up the fields that depend on the data from the main cursor.
- * @param[in] mc The main cursor whose sorted-dups cursor is to be initialized.
- * @param[in] node The data containing the #MDB_db record for the
- * sorted-dup database.
- */
-static void
-mdb_xcursor_init1(MDB_cursor *mc, MDB_node *node)
-{
-	MDB_xcursor *mx = mc->mc_xcursor;
-
-	mx->mx_cursor.mc_flags &= C_SUB|C_ORIG_RDONLY|C_WRITEMAP;
-	if (node->mn_flags & F_SUBDATA) {
-		memcpy(&mx->mx_db, NODEDATA(node), sizeof(MDB_db));
-		mx->mx_cursor.mc_pg[0] = 0;
-		mx->mx_cursor.mc_snum = 0;
-		mx->mx_cursor.mc_top = 0;
-	} else {
-		MDB_page *fp = NODEDATA(node);
-		mx->mx_db.md_pad = 0;
-		mx->mx_db.md_flags = 0;
-		mx->mx_db.md_depth = 1;
-		mx->mx_db.md_branch_pages = 0;
-		mx->mx_db.md_leaf_pages = 1;
-		mx->mx_db.md_overflow_pages = 0;
-		mx->mx_db.md_entries = NUMKEYS(fp);
-		COPY_PGNO(mx->mx_db.md_root, fp->mp_pgno);
-		mx->mx_cursor.mc_snum = 1;
-		mx->mx_cursor.mc_top = 0;
-		mx->mx_cursor.mc_flags |= C_INITIALIZED;
-		mx->mx_cursor.mc_pg[0] = fp;
-		mx->mx_cursor.mc_ki[0] = 0;
-		if (mc->mc_db->md_flags & MDB_DUPFIXED) {
-			mx->mx_db.md_flags = MDB_DUPFIXED;
-			mx->mx_db.md_pad = fp->mp_pad;
-			if (mc->mc_db->md_flags & MDB_INTEGERDUP)
-				mx->mx_db.md_flags |= MDB_INTEGERKEY;
-		}
-	}
-	DPRINTF(("Sub-db -%u root page %"Y"u", mx->mx_cursor.mc_dbi,
-		mx->mx_db.md_root));
-	mx->mx_dbflag = DB_VALID|DB_USRVALID|DB_DIRTY; /* DB_DIRTY guides mdb_cursor_touch */
-#if UINT_MAX < SIZE_MAX || defined(MDB_VL32)
-	if (mx->mx_dbx.md_cmp == mdb_cmp_int && mx->mx_db.md_pad == sizeof(mdb_size_t))
-		mx->mx_dbx.md_cmp = mdb_cmp_clong;
-#endif
-}
-
-
-/** Fixup a sorted-dups cursor due to underlying update.
- *	Sets up some fields that depend on the data from the main cursor.
- *	Almost the same as init1, but skips initialization steps if the
- *	xcursor had already been used.
- * @param[in] mc The main cursor whose sorted-dups cursor is to be fixed up.
- * @param[in] src_mx The xcursor of an up-to-date cursor.
- * @param[in] new_dupdata True if converting from a non-#F_DUPDATA item.
- */
-static void
-mdb_xcursor_init2(MDB_cursor *mc, MDB_xcursor *src_mx, int new_dupdata)
-{
-	MDB_xcursor *mx = mc->mc_xcursor;
-
-	if (new_dupdata) {
-		mx->mx_cursor.mc_snum = 1;
-		mx->mx_cursor.mc_top = 0;
-		mx->mx_cursor.mc_flags |= C_INITIALIZED;
-		mx->mx_cursor.mc_ki[0] = 0;
-		mx->mx_dbflag = DB_VALID|DB_USRVALID|DB_DIRTY; /* DB_DIRTY guides mdb_cursor_touch */
-#if UINT_MAX < SIZE_MAX
-		mx->mx_dbx.md_cmp = src_mx->mx_dbx.md_cmp;
-#endif
-	} else if (!(mx->mx_cursor.mc_flags & C_INITIALIZED)) {
-		return;
-	}
-	mx->mx_db = src_mx->mx_db;
-	mx->mx_cursor.mc_pg[0] = src_mx->mx_cursor.mc_pg[0];
-	DPRINTF(("Sub-db -%u root page %"Y"u", mx->mx_cursor.mc_dbi,
-		mx->mx_db.md_root));
-}
-
-/** Initialize a cursor for a given transaction and database. */
-static void
-mdb_cursor_init(MDB_cursor *mc, MDB_txn *txn, MDB_dbi dbi, MDB_xcursor *mx)
-{
-	mc->mc_next = NULL;
-	mc->mc_backup = NULL;
-	mc->mc_dbi = dbi;
-	mc->mc_txn = txn;
-	mc->mc_db = &txn->mt_dbs[dbi];
-	mc->mc_dbx = &txn->mt_dbxs[dbi];
-	mc->mc_dbflag = &txn->mt_dbflags[dbi];
-	mc->mc_snum = 0;
-	mc->mc_top = 0;
-	mc->mc_pg[0] = 0;
-	mc->mc_ki[0] = 0;
-#ifdef MDB_VL32
-	mc->mc_ovpg = 0;
-#endif
-	mc->mc_flags = txn->mt_flags & (C_ORIG_RDONLY|C_WRITEMAP);
-	if (txn->mt_dbs[dbi].md_flags & MDB_DUPSORT) {
-		mdb_tassert(txn, mx != NULL);
-		mc->mc_xcursor = mx;
-		mdb_xcursor_init0(mc);
-	} else {
-		mc->mc_xcursor = NULL;
-	}
-	if (*mc->mc_dbflag & DB_STALE) {
-		mdb_page_search(mc, NULL, MDB_PS_ROOTONLY);
-	}
-}
-
-int
-mdb_cursor_open(MDB_txn *txn, MDB_dbi dbi, MDB_cursor **ret)
-{
-	MDB_cursor	*mc;
-	size_t size = sizeof(MDB_cursor);
-
-	if (!ret || !TXN_DBI_EXIST(txn, dbi, DB_VALID))
-		return EINVAL;
-
-	if (txn->mt_flags & MDB_TXN_BLOCKED)
-		return MDB_BAD_TXN;
-
-	if (dbi == FREE_DBI && !F_ISSET(txn->mt_flags, MDB_TXN_RDONLY))
-		return EINVAL;
-
-	if (txn->mt_dbs[dbi].md_flags & MDB_DUPSORT)
-		size += sizeof(MDB_xcursor);
-
-	if ((mc = malloc(size)) != NULL) {
-		mdb_cursor_init(mc, txn, dbi, (MDB_xcursor *)(mc + 1));
-		if (txn->mt_cursors) {
-			mc->mc_next = txn->mt_cursors[dbi];
-			txn->mt_cursors[dbi] = mc;
-			mc->mc_flags |= C_UNTRACK;
-		}
-	} else {
-		return ENOMEM;
-	}
-
-	*ret = mc;
-
-	return MDB_SUCCESS;
-}
-
-int
-mdb_cursor_renew(MDB_txn *txn, MDB_cursor *mc)
-{
-	if (!mc || !TXN_DBI_EXIST(txn, mc->mc_dbi, DB_VALID))
-		return EINVAL;
-
-	if ((mc->mc_flags & C_UNTRACK) || txn->mt_cursors)
-		return EINVAL;
-
-	if (txn->mt_flags & MDB_TXN_BLOCKED)
-		return MDB_BAD_TXN;
-
-	mdb_cursor_init(mc, txn, mc->mc_dbi, mc->mc_xcursor);
-	return MDB_SUCCESS;
-}
-
-/* Return the count of duplicate data items for the current key */
-int
-mdb_cursor_count(MDB_cursor *mc, mdb_size_t *countp)
-{
-	MDB_node	*leaf;
-
-	if (mc == NULL || countp == NULL)
-		return EINVAL;
-
-	if (mc->mc_xcursor == NULL)
-		return MDB_INCOMPATIBLE;
-
-	if (mc->mc_txn->mt_flags & MDB_TXN_BLOCKED)
-		return MDB_BAD_TXN;
-
-	if (!(mc->mc_flags & C_INITIALIZED))
-		return EINVAL;
-
-	if (!mc->mc_snum || (mc->mc_flags & C_EOF))
-		return MDB_NOTFOUND;
-
-	leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
-	if (!F_ISSET(leaf->mn_flags, F_DUPDATA)) {
-		*countp = 1;
-	} else {
-		if (!(mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED))
-			return EINVAL;
-
-		*countp = mc->mc_xcursor->mx_db.md_entries;
-	}
-	return MDB_SUCCESS;
-}
-
-void
-mdb_cursor_close(MDB_cursor *mc)
-{
-	if (mc && !mc->mc_backup) {
-		/* remove from txn, if tracked */
-		if ((mc->mc_flags & C_UNTRACK) && mc->mc_txn->mt_cursors) {
-			MDB_cursor **prev = &mc->mc_txn->mt_cursors[mc->mc_dbi];
-			while (*prev && *prev != mc) prev = &(*prev)->mc_next;
-			if (*prev == mc)
-				*prev = mc->mc_next;
-		}
-		free(mc);
-	}
-}
-
-MDB_txn *
-mdb_cursor_txn(MDB_cursor *mc)
-{
-	if (!mc) return NULL;
-	return mc->mc_txn;
-}
-
-MDB_dbi
-mdb_cursor_dbi(MDB_cursor *mc)
-{
-	return mc->mc_dbi;
-}
-
-/** Replace the key for a branch node with a new key.
- * @param[in] mc Cursor pointing to the node to operate on.
- * @param[in] key The new key to use.
- * @return 0 on success, non-zero on failure.
- */
-static int
-mdb_update_key(MDB_cursor *mc, MDB_val *key)
-{
-	MDB_page		*mp;
-	MDB_node		*node;
-	char			*base;
-	size_t			 len;
-	int				 delta, ksize, oksize;
-	indx_t			 ptr, i, numkeys, indx;
-	DKBUF;
-
-	indx = mc->mc_ki[mc->mc_top];
-	mp = mc->mc_pg[mc->mc_top];
-	node = NODEPTR(mp, indx);
-	ptr = mp->mp_ptrs[indx];
-#if MDB_DEBUG
-	{
-		MDB_val	k2;
-		char kbuf2[DKBUF_MAXKEYSIZE*2+1];
-		k2.mv_data = NODEKEY(node);
-		k2.mv_size = node->mn_ksize;
-		DPRINTF(("update key %u (ofs %u) [%s] to [%s] on page %"Y"u",
-			indx, ptr,
-			mdb_dkey(&k2, kbuf2),
-			DKEY(key),
-			mp->mp_pgno));
-	}
-#endif
-
-	/* Sizes must be 2-byte aligned. */
-	ksize = EVEN(key->mv_size);
-	oksize = EVEN(node->mn_ksize);
-	delta = ksize - oksize;
-
-	/* Shift node contents if EVEN(key length) changed. */
-	if (delta) {
-		if (delta > 0 && SIZELEFT(mp) < delta) {
-			pgno_t pgno;
-			/* not enough space left, do a delete and split */
-			DPRINTF(("Not enough room, delta = %d, splitting...", delta));
-			pgno = NODEPGNO(node);
-			mdb_node_del(mc, 0);
-			return mdb_page_split(mc, key, NULL, pgno, MDB_SPLIT_REPLACE);
-		}
-
-		numkeys = NUMKEYS(mp);
-		for (i = 0; i < numkeys; i++) {
-			if (mp->mp_ptrs[i] <= ptr)
-				mp->mp_ptrs[i] -= delta;
-		}
-
-		base = (char *)mp + mp->mp_upper + PAGEBASE;
-		len = ptr - mp->mp_upper + NODESIZE;
-		memmove(base - delta, base, len);
-		mp->mp_upper -= delta;
-
-		node = NODEPTR(mp, indx);
-	}
-
-	/* But even if no shift was needed, update ksize */
-	if (node->mn_ksize != key->mv_size)
-		node->mn_ksize = key->mv_size;
-
-	if (key->mv_size)
-		memcpy(NODEKEY(node), key->mv_data, key->mv_size);
-
-	return MDB_SUCCESS;
-}
-
-static void
-mdb_cursor_copy(const MDB_cursor *csrc, MDB_cursor *cdst);
-
-/** Perform \b act while tracking temporary cursor \b mn */
-#define WITH_CURSOR_TRACKING(mn, act) do { \
-	MDB_cursor dummy, *tracked, **tp = &(mn).mc_txn->mt_cursors[mn.mc_dbi]; \
-	if ((mn).mc_flags & C_SUB) { \
-		dummy.mc_flags =  C_INITIALIZED; \
-		dummy.mc_xcursor = (MDB_xcursor *)&(mn);	\
-		tracked = &dummy; \
-	} else { \
-		tracked = &(mn); \
-	} \
-	tracked->mc_next = *tp; \
-	*tp = tracked; \
-	{ act; } \
-	*tp = tracked->mc_next; \
-} while (0)
-
-/** Move a node from csrc to cdst.
- */
-static int
-mdb_node_move(MDB_cursor *csrc, MDB_cursor *cdst, int fromleft)
-{
-	MDB_node		*srcnode;
-	MDB_val		 key, data;
-	pgno_t	srcpg;
-	MDB_cursor mn;
-	int			 rc;
-	unsigned short flags;
-
-	DKBUF;
-
-	/* Mark src and dst as dirty. */
-	if ((rc = mdb_page_touch(csrc)) ||
-	    (rc = mdb_page_touch(cdst)))
-		return rc;
-
-	if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
-		key.mv_size = csrc->mc_db->md_pad;
-		key.mv_data = LEAF2KEY(csrc->mc_pg[csrc->mc_top], csrc->mc_ki[csrc->mc_top], key.mv_size);
-		data.mv_size = 0;
-		data.mv_data = NULL;
-		srcpg = 0;
-		flags = 0;
-	} else {
-		srcnode = NODEPTR(csrc->mc_pg[csrc->mc_top], csrc->mc_ki[csrc->mc_top]);
-		mdb_cassert(csrc, !((size_t)srcnode & 1));
-		srcpg = NODEPGNO(srcnode);
-		flags = srcnode->mn_flags;
-		if (csrc->mc_ki[csrc->mc_top] == 0 && IS_BRANCH(csrc->mc_pg[csrc->mc_top])) {
-			unsigned int snum = csrc->mc_snum;
-			MDB_node *s2;
-			/* must find the lowest key below src */
-			rc = mdb_page_search_lowest(csrc);
-			if (rc)
-				return rc;
-			if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
-				key.mv_size = csrc->mc_db->md_pad;
-				key.mv_data = LEAF2KEY(csrc->mc_pg[csrc->mc_top], 0, key.mv_size);
-			} else {
-				s2 = NODEPTR(csrc->mc_pg[csrc->mc_top], 0);
-				key.mv_size = NODEKSZ(s2);
-				key.mv_data = NODEKEY(s2);
-			}
-			csrc->mc_snum = snum--;
-			csrc->mc_top = snum;
-		} else {
-			key.mv_size = NODEKSZ(srcnode);
-			key.mv_data = NODEKEY(srcnode);
-		}
-		data.mv_size = NODEDSZ(srcnode);
-		data.mv_data = NODEDATA(srcnode);
-	}
-	mn.mc_xcursor = NULL;
-	if (IS_BRANCH(cdst->mc_pg[cdst->mc_top]) && cdst->mc_ki[cdst->mc_top] == 0) {
-		unsigned int snum = cdst->mc_snum;
-		MDB_node *s2;
-		MDB_val bkey;
-		/* must find the lowest key below dst */
-		mdb_cursor_copy(cdst, &mn);
-		rc = mdb_page_search_lowest(&mn);
-		if (rc)
-			return rc;
-		if (IS_LEAF2(mn.mc_pg[mn.mc_top])) {
-			bkey.mv_size = mn.mc_db->md_pad;
-			bkey.mv_data = LEAF2KEY(mn.mc_pg[mn.mc_top], 0, bkey.mv_size);
-		} else {
-			s2 = NODEPTR(mn.mc_pg[mn.mc_top], 0);
-			bkey.mv_size = NODEKSZ(s2);
-			bkey.mv_data = NODEKEY(s2);
-		}
-		mn.mc_snum = snum--;
-		mn.mc_top = snum;
-		mn.mc_ki[snum] = 0;
-		rc = mdb_update_key(&mn, &bkey);
-		if (rc)
-			return rc;
-	}
-
-	DPRINTF(("moving %s node %u [%s] on page %"Y"u to node %u on page %"Y"u",
-	    IS_LEAF(csrc->mc_pg[csrc->mc_top]) ? "leaf" : "branch",
-	    csrc->mc_ki[csrc->mc_top],
-		DKEY(&key),
-	    csrc->mc_pg[csrc->mc_top]->mp_pgno,
-	    cdst->mc_ki[cdst->mc_top], cdst->mc_pg[cdst->mc_top]->mp_pgno));
-
-	/* Add the node to the destination page.
-	 */
-	rc = mdb_node_add(cdst, cdst->mc_ki[cdst->mc_top], &key, &data, srcpg, flags);
-	if (rc != MDB_SUCCESS)
-		return rc;
-
-	/* Delete the node from the source page.
-	 */
-	mdb_node_del(csrc, key.mv_size);
-
-	{
-		/* Adjust other cursors pointing to mp */
-		MDB_cursor *m2, *m3;
-		MDB_dbi dbi = csrc->mc_dbi;
-		MDB_page *mpd, *mps;
-
-		mps = csrc->mc_pg[csrc->mc_top];
-		/* If we're adding on the left, bump others up */
-		if (fromleft) {
-			mpd = cdst->mc_pg[csrc->mc_top];
-			for (m2 = csrc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
-				if (csrc->mc_flags & C_SUB)
-					m3 = &m2->mc_xcursor->mx_cursor;
-				else
-					m3 = m2;
-				if (!(m3->mc_flags & C_INITIALIZED) || m3->mc_top < csrc->mc_top)
-					continue;
-				if (m3 != cdst &&
-					m3->mc_pg[csrc->mc_top] == mpd &&
-					m3->mc_ki[csrc->mc_top] >= cdst->mc_ki[csrc->mc_top]) {
-					m3->mc_ki[csrc->mc_top]++;
-				}
-				if (m3 !=csrc &&
-					m3->mc_pg[csrc->mc_top] == mps &&
-					m3->mc_ki[csrc->mc_top] == csrc->mc_ki[csrc->mc_top]) {
-					m3->mc_pg[csrc->mc_top] = cdst->mc_pg[cdst->mc_top];
-					m3->mc_ki[csrc->mc_top] = cdst->mc_ki[cdst->mc_top];
-					m3->mc_ki[csrc->mc_top-1]++;
-				}
-				if (m3->mc_xcursor && (m3->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED) &&
-					IS_LEAF(mps)) {
-					MDB_node *node = NODEPTR(m3->mc_pg[csrc->mc_top], m3->mc_ki[csrc->mc_top]);
-					if ((node->mn_flags & (F_DUPDATA|F_SUBDATA)) == F_DUPDATA)
-						m3->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(node);
-				}
-			}
-		} else
-		/* Adding on the right, bump others down */
-		{
-			for (m2 = csrc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
-				if (csrc->mc_flags & C_SUB)
-					m3 = &m2->mc_xcursor->mx_cursor;
-				else
-					m3 = m2;
-				if (m3 == csrc) continue;
-				if (!(m3->mc_flags & C_INITIALIZED) || m3->mc_top < csrc->mc_top)
-					continue;
-				if (m3->mc_pg[csrc->mc_top] == mps) {
-					if (!m3->mc_ki[csrc->mc_top]) {
-						m3->mc_pg[csrc->mc_top] = cdst->mc_pg[cdst->mc_top];
-						m3->mc_ki[csrc->mc_top] = cdst->mc_ki[cdst->mc_top];
-						m3->mc_ki[csrc->mc_top-1]--;
-					} else {
-						m3->mc_ki[csrc->mc_top]--;
-					}
-					if (m3->mc_xcursor && (m3->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED) &&
-						IS_LEAF(mps)) {
-						MDB_node *node = NODEPTR(m3->mc_pg[csrc->mc_top], m3->mc_ki[csrc->mc_top]);
-						if ((node->mn_flags & (F_DUPDATA|F_SUBDATA)) == F_DUPDATA)
-							m3->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(node);
-					}
-				}
-			}
-		}
-	}
-
-	/* Update the parent separators.
-	 */
-	if (csrc->mc_ki[csrc->mc_top] == 0) {
-		if (csrc->mc_ki[csrc->mc_top-1] != 0) {
-			if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
-				key.mv_data = LEAF2KEY(csrc->mc_pg[csrc->mc_top], 0, key.mv_size);
-			} else {
-				srcnode = NODEPTR(csrc->mc_pg[csrc->mc_top], 0);
-				key.mv_size = NODEKSZ(srcnode);
-				key.mv_data = NODEKEY(srcnode);
-			}
-			DPRINTF(("update separator for source page %"Y"u to [%s]",
-				csrc->mc_pg[csrc->mc_top]->mp_pgno, DKEY(&key)));
-			mdb_cursor_copy(csrc, &mn);
-			mn.mc_snum--;
-			mn.mc_top--;
-			/* We want mdb_rebalance to find mn when doing fixups */
-			WITH_CURSOR_TRACKING(mn,
-				rc = mdb_update_key(&mn, &key));
-			if (rc)
-				return rc;
-		}
-		if (IS_BRANCH(csrc->mc_pg[csrc->mc_top])) {
-			MDB_val	 nullkey;
-			indx_t	ix = csrc->mc_ki[csrc->mc_top];
-			nullkey.mv_size = 0;
-			csrc->mc_ki[csrc->mc_top] = 0;
-			rc = mdb_update_key(csrc, &nullkey);
-			csrc->mc_ki[csrc->mc_top] = ix;
-			mdb_cassert(csrc, rc == MDB_SUCCESS);
-		}
-	}
-
-	if (cdst->mc_ki[cdst->mc_top] == 0) {
-		if (cdst->mc_ki[cdst->mc_top-1] != 0) {
-			if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
-				key.mv_data = LEAF2KEY(cdst->mc_pg[cdst->mc_top], 0, key.mv_size);
-			} else {
-				srcnode = NODEPTR(cdst->mc_pg[cdst->mc_top], 0);
-				key.mv_size = NODEKSZ(srcnode);
-				key.mv_data = NODEKEY(srcnode);
-			}
-			DPRINTF(("update separator for destination page %"Y"u to [%s]",
-				cdst->mc_pg[cdst->mc_top]->mp_pgno, DKEY(&key)));
-			mdb_cursor_copy(cdst, &mn);
-			mn.mc_snum--;
-			mn.mc_top--;
-			/* We want mdb_rebalance to find mn when doing fixups */
-			WITH_CURSOR_TRACKING(mn,
-				rc = mdb_update_key(&mn, &key));
-			if (rc)
-				return rc;
-		}
-		if (IS_BRANCH(cdst->mc_pg[cdst->mc_top])) {
-			MDB_val	 nullkey;
-			indx_t	ix = cdst->mc_ki[cdst->mc_top];
-			nullkey.mv_size = 0;
-			cdst->mc_ki[cdst->mc_top] = 0;
-			rc = mdb_update_key(cdst, &nullkey);
-			cdst->mc_ki[cdst->mc_top] = ix;
-			mdb_cassert(cdst, rc == MDB_SUCCESS);
-		}
-	}
-
-	return MDB_SUCCESS;
-}
-
-/** Merge one page into another.
- *  The nodes from the page pointed to by \b csrc will
- *	be copied to the page pointed to by \b cdst and then
- *	the \b csrc page will be freed.
- * @param[in] csrc Cursor pointing to the source page.
- * @param[in] cdst Cursor pointing to the destination page.
- * @return 0 on success, non-zero on failure.
- */
-static int
-mdb_page_merge(MDB_cursor *csrc, MDB_cursor *cdst)
-{
-	MDB_page	*psrc, *pdst;
-	MDB_node	*srcnode;
-	MDB_val		 key, data;
-	unsigned	 nkeys;
-	int			 rc;
-	indx_t		 i, j;
-
-	psrc = csrc->mc_pg[csrc->mc_top];
-	pdst = cdst->mc_pg[cdst->mc_top];
-
-	DPRINTF(("merging page %"Y"u into %"Y"u", psrc->mp_pgno, pdst->mp_pgno));
-
-	mdb_cassert(csrc, csrc->mc_snum > 1);	/* can't merge root page */
-	mdb_cassert(csrc, cdst->mc_snum > 1);
-
-	/* Mark dst as dirty. */
-	if ((rc = mdb_page_touch(cdst)))
-		return rc;
-
-	/* get dst page again now that we've touched it. */
-	pdst = cdst->mc_pg[cdst->mc_top];
-
-	/* Move all nodes from src to dst.
-	 */
-	j = nkeys = NUMKEYS(pdst);
-	if (IS_LEAF2(psrc)) {
-		key.mv_size = csrc->mc_db->md_pad;
-		key.mv_data = METADATA(psrc);
-		for (i = 0; i < NUMKEYS(psrc); i++, j++) {
-			rc = mdb_node_add(cdst, j, &key, NULL, 0, 0);
-			if (rc != MDB_SUCCESS)
-				return rc;
-			key.mv_data = (char *)key.mv_data + key.mv_size;
-		}
-	} else {
-		for (i = 0; i < NUMKEYS(psrc); i++, j++) {
-			srcnode = NODEPTR(psrc, i);
-			if (i == 0 && IS_BRANCH(psrc)) {
-				MDB_cursor mn;
-				MDB_node *s2;
-				mdb_cursor_copy(csrc, &mn);
-				mn.mc_xcursor = NULL;
-				/* must find the lowest key below src */
-				rc = mdb_page_search_lowest(&mn);
-				if (rc)
-					return rc;
-				if (IS_LEAF2(mn.mc_pg[mn.mc_top])) {
-					key.mv_size = mn.mc_db->md_pad;
-					key.mv_data = LEAF2KEY(mn.mc_pg[mn.mc_top], 0, key.mv_size);
-				} else {
-					s2 = NODEPTR(mn.mc_pg[mn.mc_top], 0);
-					key.mv_size = NODEKSZ(s2);
-					key.mv_data = NODEKEY(s2);
-				}
-			} else {
-				key.mv_size = srcnode->mn_ksize;
-				key.mv_data = NODEKEY(srcnode);
-			}
-
-			data.mv_size = NODEDSZ(srcnode);
-			data.mv_data = NODEDATA(srcnode);
-			rc = mdb_node_add(cdst, j, &key, &data, NODEPGNO(srcnode), srcnode->mn_flags);
-			if (rc != MDB_SUCCESS)
-				return rc;
-		}
-	}
-
-	DPRINTF(("dst page %"Y"u now has %u keys (%.1f%% filled)",
-	    pdst->mp_pgno, NUMKEYS(pdst),
-		(float)PAGEFILL(cdst->mc_txn->mt_env, pdst) / 10));
-
-	/* Unlink the src page from parent and add to free list.
-	 */
-	csrc->mc_top--;
-	mdb_node_del(csrc, 0);
-	if (csrc->mc_ki[csrc->mc_top] == 0) {
-		key.mv_size = 0;
-		rc = mdb_update_key(csrc, &key);
-		if (rc) {
-			csrc->mc_top++;
-			return rc;
-		}
-	}
-	csrc->mc_top++;
-
-	psrc = csrc->mc_pg[csrc->mc_top];
-	/* If not operating on FreeDB, allow this page to be reused
-	 * in this txn. Otherwise just add to free list.
-	 */
-	rc = mdb_page_loose(csrc, psrc);
-	if (rc)
-		return rc;
-	if (IS_LEAF(psrc))
-		csrc->mc_db->md_leaf_pages--;
-	else
-		csrc->mc_db->md_branch_pages--;
-	{
-		/* Adjust other cursors pointing to mp */
-		MDB_cursor *m2, *m3;
-		MDB_dbi dbi = csrc->mc_dbi;
-		unsigned int top = csrc->mc_top;
-
-		for (m2 = csrc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
-			if (csrc->mc_flags & C_SUB)
-				m3 = &m2->mc_xcursor->mx_cursor;
-			else
-				m3 = m2;
-			if (m3 == csrc) continue;
-			if (m3->mc_snum < csrc->mc_snum) continue;
-			if (m3->mc_pg[top] == psrc) {
-				m3->mc_pg[top] = pdst;
-				m3->mc_ki[top] += nkeys;
-				m3->mc_ki[top-1] = cdst->mc_ki[top-1];
-			} else if (m3->mc_pg[top-1] == csrc->mc_pg[top-1] &&
-				m3->mc_ki[top-1] > csrc->mc_ki[top-1]) {
-				m3->mc_ki[top-1]--;
-			}
-			if (m3->mc_xcursor && (m3->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED) &&
-				IS_LEAF(psrc)) {
-				MDB_node *node = NODEPTR(m3->mc_pg[top], m3->mc_ki[top]);
-				if ((node->mn_flags & (F_DUPDATA|F_SUBDATA)) == F_DUPDATA)
-					m3->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(node);
-			}
-		}
-	}
-	{
-		unsigned int snum = cdst->mc_snum;
-		uint16_t depth = cdst->mc_db->md_depth;
-		mdb_cursor_pop(cdst);
-		rc = mdb_rebalance(cdst);
-		/* Did the tree height change? */
-		if (depth != cdst->mc_db->md_depth)
-			snum += cdst->mc_db->md_depth - depth;
-		cdst->mc_snum = snum;
-		cdst->mc_top = snum-1;
-	}
-	return rc;
-}
-
-/** Copy the contents of a cursor.
- * @param[in] csrc The cursor to copy from.
- * @param[out] cdst The cursor to copy to.
- */
-static void
-mdb_cursor_copy(const MDB_cursor *csrc, MDB_cursor *cdst)
-{
-	unsigned int i;
-
-	cdst->mc_txn = csrc->mc_txn;
-	cdst->mc_dbi = csrc->mc_dbi;
-	cdst->mc_db  = csrc->mc_db;
-	cdst->mc_dbx = csrc->mc_dbx;
-	cdst->mc_snum = csrc->mc_snum;
-	cdst->mc_top = csrc->mc_top;
-	cdst->mc_flags = csrc->mc_flags;
-#ifdef MDB_VL32
-	cdst->mc_ovpg = csrc->mc_ovpg;
-#endif
-
-	for (i=0; i<csrc->mc_snum; i++) {
-		cdst->mc_pg[i] = csrc->mc_pg[i];
-		cdst->mc_ki[i] = csrc->mc_ki[i];
-	}
-}
-
-/** Rebalance the tree after a delete operation.
- * @param[in] mc Cursor pointing to the page where rebalancing
- * should begin.
- * @return 0 on success, non-zero on failure.
- */
-static int
-mdb_rebalance(MDB_cursor *mc)
-{
-	MDB_node	*node;
-	int rc, fromleft;
-	unsigned int ptop, minkeys, thresh;
-	MDB_cursor	mn;
-	indx_t oldki;
-
-	if (IS_BRANCH(mc->mc_pg[mc->mc_top])) {
-		minkeys = 2;
-		thresh = 1;
-	} else {
-		minkeys = 1;
-		thresh = FILL_THRESHOLD;
-	}
-	DPRINTF(("rebalancing %s page %"Y"u (has %u keys, %.1f%% full)",
-	    IS_LEAF(mc->mc_pg[mc->mc_top]) ? "leaf" : "branch",
-	    mdb_dbg_pgno(mc->mc_pg[mc->mc_top]), NUMKEYS(mc->mc_pg[mc->mc_top]),
-		(float)PAGEFILL(mc->mc_txn->mt_env, mc->mc_pg[mc->mc_top]) / 10));
-
-	if (PAGEFILL(mc->mc_txn->mt_env, mc->mc_pg[mc->mc_top]) >= thresh &&
-		NUMKEYS(mc->mc_pg[mc->mc_top]) >= minkeys) {
-		DPRINTF(("no need to rebalance page %"Y"u, above fill threshold",
-		    mdb_dbg_pgno(mc->mc_pg[mc->mc_top])));
-		return MDB_SUCCESS;
-	}
-
-	if (mc->mc_snum < 2) {
-		MDB_page *mp = mc->mc_pg[0];
-		if (IS_SUBP(mp)) {
-			DPUTS("Can't rebalance a subpage, ignoring");
-			return MDB_SUCCESS;
-		}
-		if (NUMKEYS(mp) == 0) {
-			DPUTS("tree is completely empty");
-			mc->mc_db->md_root = P_INVALID;
-			mc->mc_db->md_depth = 0;
-			mc->mc_db->md_leaf_pages = 0;
-			rc = mdb_midl_append(&mc->mc_txn->mt_free_pgs, mp->mp_pgno);
-			if (rc)
-				return rc;
-			/* Adjust cursors pointing to mp */
-			mc->mc_snum = 0;
-			mc->mc_top = 0;
-			mc->mc_flags &= ~C_INITIALIZED;
-			{
-				MDB_cursor *m2, *m3;
-				MDB_dbi dbi = mc->mc_dbi;
-
-				for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
-					if (mc->mc_flags & C_SUB)
-						m3 = &m2->mc_xcursor->mx_cursor;
-					else
-						m3 = m2;
-					if (!(m3->mc_flags & C_INITIALIZED) || (m3->mc_snum < mc->mc_snum))
-						continue;
-					if (m3->mc_pg[0] == mp) {
-						m3->mc_snum = 0;
-						m3->mc_top = 0;
-						m3->mc_flags &= ~C_INITIALIZED;
-					}
-				}
-			}
-		} else if (IS_BRANCH(mp) && NUMKEYS(mp) == 1) {
-			int i;
-			DPUTS("collapsing root page!");
-			rc = mdb_midl_append(&mc->mc_txn->mt_free_pgs, mp->mp_pgno);
-			if (rc)
-				return rc;
-			mc->mc_db->md_root = NODEPGNO(NODEPTR(mp, 0));
-			rc = mdb_page_get(mc, mc->mc_db->md_root, &mc->mc_pg[0], NULL);
-			if (rc)
-				return rc;
-			mc->mc_db->md_depth--;
-			mc->mc_db->md_branch_pages--;
-			mc->mc_ki[0] = mc->mc_ki[1];
-			for (i = 1; i<mc->mc_db->md_depth; i++) {
-				mc->mc_pg[i] = mc->mc_pg[i+1];
-				mc->mc_ki[i] = mc->mc_ki[i+1];
-			}
-			{
-				/* Adjust other cursors pointing to mp */
-				MDB_cursor *m2, *m3;
-				MDB_dbi dbi = mc->mc_dbi;
-
-				for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
-					if (mc->mc_flags & C_SUB)
-						m3 = &m2->mc_xcursor->mx_cursor;
-					else
-						m3 = m2;
-					if (m3 == mc) continue;
-					if (!(m3->mc_flags & C_INITIALIZED))
-						continue;
-					if (m3->mc_pg[0] == mp) {
-						for (i=0; i<mc->mc_db->md_depth; i++) {
-							m3->mc_pg[i] = m3->mc_pg[i+1];
-							m3->mc_ki[i] = m3->mc_ki[i+1];
-						}
-						m3->mc_snum--;
-						m3->mc_top--;
-					}
-				}
-			}
-		} else
-			DPUTS("root page doesn't need rebalancing");
-		return MDB_SUCCESS;
-	}
-
-	/* The parent (branch page) must have at least 2 pointers,
-	 * otherwise the tree is invalid.
-	 */
-	ptop = mc->mc_top-1;
-	mdb_cassert(mc, NUMKEYS(mc->mc_pg[ptop]) > 1);
-
-	/* Leaf page fill factor is below the threshold.
-	 * Try to move keys from left or right neighbor, or
-	 * merge with a neighbor page.
-	 */
-
-	/* Find neighbors.
-	 */
-	mdb_cursor_copy(mc, &mn);
-	mn.mc_xcursor = NULL;
-
-	oldki = mc->mc_ki[mc->mc_top];
-	if (mc->mc_ki[ptop] == 0) {
-		/* We're the leftmost leaf in our parent.
-		 */
-		DPUTS("reading right neighbor");
-		mn.mc_ki[ptop]++;
-		node = NODEPTR(mc->mc_pg[ptop], mn.mc_ki[ptop]);
-		rc = mdb_page_get(mc, NODEPGNO(node), &mn.mc_pg[mn.mc_top], NULL);
-		if (rc)
-			return rc;
-		mn.mc_ki[mn.mc_top] = 0;
-		mc->mc_ki[mc->mc_top] = NUMKEYS(mc->mc_pg[mc->mc_top]);
-		fromleft = 0;
-	} else {
-		/* There is at least one neighbor to the left.
-		 */
-		DPUTS("reading left neighbor");
-		mn.mc_ki[ptop]--;
-		node = NODEPTR(mc->mc_pg[ptop], mn.mc_ki[ptop]);
-		rc = mdb_page_get(mc, NODEPGNO(node), &mn.mc_pg[mn.mc_top], NULL);
-		if (rc)
-			return rc;
-		mn.mc_ki[mn.mc_top] = NUMKEYS(mn.mc_pg[mn.mc_top]) - 1;
-		mc->mc_ki[mc->mc_top] = 0;
-		fromleft = 1;
-	}
-
-	DPRINTF(("found neighbor page %"Y"u (%u keys, %.1f%% full)",
-	    mn.mc_pg[mn.mc_top]->mp_pgno, NUMKEYS(mn.mc_pg[mn.mc_top]),
-		(float)PAGEFILL(mc->mc_txn->mt_env, mn.mc_pg[mn.mc_top]) / 10));
-
-	/* If the neighbor page is above threshold and has enough keys,
-	 * move one key from it. Otherwise we should try to merge them.
-	 * (A branch page must never have less than 2 keys.)
-	 */
-	if (PAGEFILL(mc->mc_txn->mt_env, mn.mc_pg[mn.mc_top]) >= thresh && NUMKEYS(mn.mc_pg[mn.mc_top]) > minkeys) {
-		rc = mdb_node_move(&mn, mc, fromleft);
-		if (fromleft) {
-			/* if we inserted on left, bump position up */
-			oldki++;
-		}
-	} else {
-		if (!fromleft) {
-			rc = mdb_page_merge(&mn, mc);
-		} else {
-			oldki += NUMKEYS(mn.mc_pg[mn.mc_top]);
-			mn.mc_ki[mn.mc_top] += mc->mc_ki[mn.mc_top] + 1;
-			/* We want mdb_rebalance to find mn when doing fixups */
-			WITH_CURSOR_TRACKING(mn,
-				rc = mdb_page_merge(mc, &mn));
-			mdb_cursor_copy(&mn, mc);
-		}
-		mc->mc_flags &= ~C_EOF;
-	}
-	mc->mc_ki[mc->mc_top] = oldki;
-	return rc;
-}
-
-/** Complete a delete operation started by #mdb_cursor_del(). */
-static int
-mdb_cursor_del0(MDB_cursor *mc)
-{
-	int rc;
-	MDB_page *mp;
-	indx_t ki;
-	unsigned int nkeys;
-	MDB_cursor *m2, *m3;
-	MDB_dbi dbi = mc->mc_dbi;
-
-	ki = mc->mc_ki[mc->mc_top];
-	mp = mc->mc_pg[mc->mc_top];
-	mdb_node_del(mc, mc->mc_db->md_pad);
-	mc->mc_db->md_entries--;
-	{
-		/* Adjust other cursors pointing to mp */
-		for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
-			m3 = (mc->mc_flags & C_SUB) ? &m2->mc_xcursor->mx_cursor : m2;
-			if (! (m2->mc_flags & m3->mc_flags & C_INITIALIZED))
-				continue;
-			if (m3 == mc || m3->mc_snum < mc->mc_snum)
-				continue;
-			if (m3->mc_pg[mc->mc_top] == mp) {
-				if (m3->mc_ki[mc->mc_top] == ki) {
-					m3->mc_flags |= C_DEL;
-				} else if (m3->mc_ki[mc->mc_top] > ki) {
-					m3->mc_ki[mc->mc_top]--;
-				}
-				if (m3->mc_xcursor && (m3->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED)) {
-					MDB_node *node = NODEPTR(m3->mc_pg[mc->mc_top], m3->mc_ki[mc->mc_top]);
-					if ((node->mn_flags & (F_DUPDATA|F_SUBDATA)) == F_DUPDATA)
-						m3->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(node);
-				}
-			}
-		}
-	}
-	rc = mdb_rebalance(mc);
-
-	if (rc == MDB_SUCCESS) {
-		/* DB is totally empty now, just bail out.
-		 * Other cursors adjustments were already done
-		 * by mdb_rebalance and aren't needed here.
-		 */
-		if (!mc->mc_snum)
-			return rc;
-
-		mp = mc->mc_pg[mc->mc_top];
-		nkeys = NUMKEYS(mp);
-
-		/* Adjust other cursors pointing to mp */
-		for (m2 = mc->mc_txn->mt_cursors[dbi]; !rc && m2; m2=m2->mc_next) {
-			m3 = (mc->mc_flags & C_SUB) ? &m2->mc_xcursor->mx_cursor : m2;
-			if (! (m2->mc_flags & m3->mc_flags & C_INITIALIZED))
-				continue;
-			if (m3->mc_snum < mc->mc_snum)
-				continue;
-			if (m3->mc_pg[mc->mc_top] == mp) {
-				/* if m3 points past last node in page, find next sibling */
-				if (m3->mc_ki[mc->mc_top] >= mc->mc_ki[mc->mc_top]) {
-					if (m3->mc_ki[mc->mc_top] >= nkeys) {
-						rc = mdb_cursor_sibling(m3, 1);
-						if (rc == MDB_NOTFOUND) {
-							m3->mc_flags |= C_EOF;
-							rc = MDB_SUCCESS;
-							continue;
-						}
-					}
-					if (mc->mc_db->md_flags & MDB_DUPSORT) {
-						MDB_node *node = NODEPTR(m3->mc_pg[m3->mc_top], m3->mc_ki[m3->mc_top]);
-						if (node->mn_flags & F_DUPDATA) {
-							mdb_xcursor_init1(m3, node);
-							m3->mc_xcursor->mx_cursor.mc_flags |= C_DEL;
-						}
-					}
-				}
-			}
-		}
-		mc->mc_flags |= C_DEL;
-	}
-
-	if (rc)
-		mc->mc_txn->mt_flags |= MDB_TXN_ERROR;
-	return rc;
-}
-
-int
-mdb_del(MDB_txn *txn, MDB_dbi dbi,
-    MDB_val *key, MDB_val *data)
-{
-	if (!key || !TXN_DBI_EXIST(txn, dbi, DB_USRVALID))
-		return EINVAL;
-
-	if (txn->mt_flags & (MDB_TXN_RDONLY|MDB_TXN_BLOCKED))
-		return (txn->mt_flags & MDB_TXN_RDONLY) ? EACCES : MDB_BAD_TXN;
-
-	if (!F_ISSET(txn->mt_dbs[dbi].md_flags, MDB_DUPSORT)) {
-		/* must ignore any data */
-		data = NULL;
-	}
-
-	return mdb_del0(txn, dbi, key, data, 0);
-}
-
-static int
-mdb_del0(MDB_txn *txn, MDB_dbi dbi,
-	MDB_val *key, MDB_val *data, unsigned flags)
-{
-	MDB_cursor mc;
-	MDB_xcursor mx;
-	MDB_cursor_op op;
-	MDB_val rdata, *xdata;
-	int		 rc, exact = 0;
-	DKBUF;
-
-	DPRINTF(("====> delete db %u key [%s]", dbi, DKEY(key)));
-
-	mdb_cursor_init(&mc, txn, dbi, &mx);
-
-	if (data) {
-		op = MDB_GET_BOTH;
-		rdata = *data;
-		xdata = &rdata;
-	} else {
-		op = MDB_SET;
-		xdata = NULL;
-		flags |= MDB_NODUPDATA;
-	}
-	rc = mdb_cursor_set(&mc, key, xdata, op, &exact);
-	if (rc == 0) {
-		/* let mdb_page_split know about this cursor if needed:
-		 * delete will trigger a rebalance; if it needs to move
-		 * a node from one page to another, it will have to
-		 * update the parent's separator key(s). If the new sepkey
-		 * is larger than the current one, the parent page may
-		 * run out of space, triggering a split. We need this
-		 * cursor to be consistent until the end of the rebalance.
-		 */
-		mc.mc_flags |= C_UNTRACK;
-		mc.mc_next = txn->mt_cursors[dbi];
-		txn->mt_cursors[dbi] = &mc;
-		rc = mdb_cursor_del(&mc, flags);
-		txn->mt_cursors[dbi] = mc.mc_next;
-	}
-	return rc;
-}
-
-/** Split a page and insert a new node.
- * @param[in,out] mc Cursor pointing to the page and desired insertion index.
- * The cursor will be updated to point to the actual page and index where
- * the node got inserted after the split.
- * @param[in] newkey The key for the newly inserted node.
- * @param[in] newdata The data for the newly inserted node.
- * @param[in] newpgno The page number, if the new node is a branch node.
- * @param[in] nflags The #NODE_ADD_FLAGS for the new node.
- * @return 0 on success, non-zero on failure.
- */
-static int
-mdb_page_split(MDB_cursor *mc, MDB_val *newkey, MDB_val *newdata, pgno_t newpgno,
-	unsigned int nflags)
-{
-	unsigned int flags;
-	int		 rc = MDB_SUCCESS, new_root = 0, did_split = 0;
-	indx_t		 newindx;
-	pgno_t		 pgno = 0;
-	int	 i, j, split_indx, nkeys, pmax;
-	MDB_env 	*env = mc->mc_txn->mt_env;
-	MDB_node	*node;
-	MDB_val	 sepkey, rkey, xdata, *rdata = &xdata;
-	MDB_page	*copy = NULL;
-	MDB_page	*mp, *rp, *pp;
-	int ptop;
-	MDB_cursor	mn;
-	DKBUF;
-
-	mp = mc->mc_pg[mc->mc_top];
-	newindx = mc->mc_ki[mc->mc_top];
-	nkeys = NUMKEYS(mp);
-
-	DPRINTF(("-----> splitting %s page %"Y"u and adding [%s] at index %i/%i",
-	    IS_LEAF(mp) ? "leaf" : "branch", mp->mp_pgno,
-	    DKEY(newkey), mc->mc_ki[mc->mc_top], nkeys));
-
-	/* Create a right sibling. */
-	if ((rc = mdb_page_new(mc, mp->mp_flags, 1, &rp)))
-		return rc;
-	rp->mp_pad = mp->mp_pad;
-	DPRINTF(("new right sibling: page %"Y"u", rp->mp_pgno));
-
-	/* Usually when splitting the root page, the cursor
-	 * height is 1. But when called from mdb_update_key,
-	 * the cursor height may be greater because it walks
-	 * up the stack while finding the branch slot to update.
-	 */
-	if (mc->mc_top < 1) {
-		if ((rc = mdb_page_new(mc, P_BRANCH, 1, &pp)))
-			goto done;
-		/* shift current top to make room for new parent */
-		for (i=mc->mc_snum; i>0; i--) {
-			mc->mc_pg[i] = mc->mc_pg[i-1];
-			mc->mc_ki[i] = mc->mc_ki[i-1];
-		}
-		mc->mc_pg[0] = pp;
-		mc->mc_ki[0] = 0;
-		mc->mc_db->md_root = pp->mp_pgno;
-		DPRINTF(("root split! new root = %"Y"u", pp->mp_pgno));
-		new_root = mc->mc_db->md_depth++;
-
-		/* Add left (implicit) pointer. */
-		if ((rc = mdb_node_add(mc, 0, NULL, NULL, mp->mp_pgno, 0)) != MDB_SUCCESS) {
-			/* undo the pre-push */
-			mc->mc_pg[0] = mc->mc_pg[1];
-			mc->mc_ki[0] = mc->mc_ki[1];
-			mc->mc_db->md_root = mp->mp_pgno;
-			mc->mc_db->md_depth--;
-			goto done;
-		}
-		mc->mc_snum++;
-		mc->mc_top++;
-		ptop = 0;
-	} else {
-		ptop = mc->mc_top-1;
-		DPRINTF(("parent branch page is %"Y"u", mc->mc_pg[ptop]->mp_pgno));
-	}
-
-	mdb_cursor_copy(mc, &mn);
-	mn.mc_xcursor = NULL;
-	mn.mc_pg[mn.mc_top] = rp;
-	mn.mc_ki[ptop] = mc->mc_ki[ptop]+1;
-
-	if (nflags & MDB_APPEND) {
-		mn.mc_ki[mn.mc_top] = 0;
-		sepkey = *newkey;
-		split_indx = newindx;
-		nkeys = 0;
-	} else {
-
-		split_indx = (nkeys+1) / 2;
-
-		if (IS_LEAF2(rp)) {
-			char *split, *ins;
-			int x;
-			unsigned int lsize, rsize, ksize;
-			/* Move half of the keys to the right sibling */
-			x = mc->mc_ki[mc->mc_top] - split_indx;
-			ksize = mc->mc_db->md_pad;
-			split = LEAF2KEY(mp, split_indx, ksize);
-			rsize = (nkeys - split_indx) * ksize;
-			lsize = (nkeys - split_indx) * sizeof(indx_t);
-			mp->mp_lower -= lsize;
-			rp->mp_lower += lsize;
-			mp->mp_upper += rsize - lsize;
-			rp->mp_upper -= rsize - lsize;
-			sepkey.mv_size = ksize;
-			if (newindx == split_indx) {
-				sepkey.mv_data = newkey->mv_data;
-			} else {
-				sepkey.mv_data = split;
-			}
-			if (x<0) {
-				ins = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], ksize);
-				memcpy(rp->mp_ptrs, split, rsize);
-				sepkey.mv_data = rp->mp_ptrs;
-				memmove(ins+ksize, ins, (split_indx - mc->mc_ki[mc->mc_top]) * ksize);
-				memcpy(ins, newkey->mv_data, ksize);
-				mp->mp_lower += sizeof(indx_t);
-				mp->mp_upper -= ksize - sizeof(indx_t);
-			} else {
-				if (x)
-					memcpy(rp->mp_ptrs, split, x * ksize);
-				ins = LEAF2KEY(rp, x, ksize);
-				memcpy(ins, newkey->mv_data, ksize);
-				memcpy(ins+ksize, split + x * ksize, rsize - x * ksize);
-				rp->mp_lower += sizeof(indx_t);
-				rp->mp_upper -= ksize - sizeof(indx_t);
-				mc->mc_ki[mc->mc_top] = x;
-			}
-		} else {
-			int psize, nsize, k;
-			/* Maximum free space in an empty page */
-			pmax = env->me_psize - PAGEHDRSZ;
-			if (IS_LEAF(mp))
-				nsize = mdb_leaf_size(env, newkey, newdata);
-			else
-				nsize = mdb_branch_size(env, newkey);
-			nsize = EVEN(nsize);
-
-			/* grab a page to hold a temporary copy */
-			copy = mdb_page_malloc(mc->mc_txn, 1);
-			if (copy == NULL) {
-				rc = ENOMEM;
-				goto done;
-			}
-			copy->mp_pgno  = mp->mp_pgno;
-			copy->mp_flags = mp->mp_flags;
-			copy->mp_lower = (PAGEHDRSZ-PAGEBASE);
-			copy->mp_upper = env->me_psize - PAGEBASE;
-
-			/* prepare to insert */
-			for (i=0, j=0; i<nkeys; i++) {
-				if (i == newindx) {
-					copy->mp_ptrs[j++] = 0;
-				}
-				copy->mp_ptrs[j++] = mp->mp_ptrs[i];
-			}
-
-			/* When items are relatively large the split point needs
-			 * to be checked, because being off-by-one will make the
-			 * difference between success or failure in mdb_node_add.
-			 *
-			 * It's also relevant if a page happens to be laid out
-			 * such that one half of its nodes are all "small" and
-			 * the other half of its nodes are "large." If the new
-			 * item is also "large" and falls on the half with
-			 * "large" nodes, it also may not fit.
-			 *
-			 * As a final tweak, if the new item goes on the last
-			 * spot on the page (and thus, onto the new page), bias
-			 * the split so the new page is emptier than the old page.
-			 * This yields better packing during sequential inserts.
-			 */
-			if (nkeys < 20 || nsize > pmax/16 || newindx >= nkeys) {
-				/* Find split point */
-				psize = 0;
-				if (newindx <= split_indx || newindx >= nkeys) {
-					i = 0; j = 1;
-					k = newindx >= nkeys ? nkeys : split_indx+1+IS_LEAF(mp);
-				} else {
-					i = nkeys; j = -1;
-					k = split_indx-1;
-				}
-				for (; i!=k; i+=j) {
-					if (i == newindx) {
-						psize += nsize;
-						node = NULL;
-					} else {
-						node = (MDB_node *)((char *)mp + copy->mp_ptrs[i] + PAGEBASE);
-						psize += NODESIZE + NODEKSZ(node) + sizeof(indx_t);
-						if (IS_LEAF(mp)) {
-							if (F_ISSET(node->mn_flags, F_BIGDATA))
-								psize += sizeof(pgno_t);
-							else
-								psize += NODEDSZ(node);
-						}
-						psize = EVEN(psize);
-					}
-					if (psize > pmax || i == k-j) {
-						split_indx = i + (j<0);
-						break;
-					}
-				}
-			}
-			if (split_indx == newindx) {
-				sepkey.mv_size = newkey->mv_size;
-				sepkey.mv_data = newkey->mv_data;
-			} else {
-				node = (MDB_node *)((char *)mp + copy->mp_ptrs[split_indx] + PAGEBASE);
-				sepkey.mv_size = node->mn_ksize;
-				sepkey.mv_data = NODEKEY(node);
-			}
-		}
-	}
-
-	DPRINTF(("separator is %d [%s]", split_indx, DKEY(&sepkey)));
-
-	/* Copy separator key to the parent.
-	 */
-	if (SIZELEFT(mn.mc_pg[ptop]) < mdb_branch_size(env, &sepkey)) {
-		int snum = mc->mc_snum;
-		mn.mc_snum--;
-		mn.mc_top--;
-		did_split = 1;
-		/* We want other splits to find mn when doing fixups */
-		WITH_CURSOR_TRACKING(mn,
-			rc = mdb_page_split(&mn, &sepkey, NULL, rp->mp_pgno, 0));
-		if (rc)
-			goto done;
-
-		/* root split? */
-		if (mc->mc_snum > snum) {
-			ptop++;
-		}
-		/* Right page might now have changed parent.
-		 * Check if left page also changed parent.
-		 */
-		if (mn.mc_pg[ptop] != mc->mc_pg[ptop] &&
-		    mc->mc_ki[ptop] >= NUMKEYS(mc->mc_pg[ptop])) {
-			for (i=0; i<ptop; i++) {
-				mc->mc_pg[i] = mn.mc_pg[i];
-				mc->mc_ki[i] = mn.mc_ki[i];
-			}
-			mc->mc_pg[ptop] = mn.mc_pg[ptop];
-			if (mn.mc_ki[ptop]) {
-				mc->mc_ki[ptop] = mn.mc_ki[ptop] - 1;
-			} else {
-				/* find right page's left sibling */
-				mc->mc_ki[ptop] = mn.mc_ki[ptop];
-				mdb_cursor_sibling(mc, 0);
-			}
-		}
-	} else {
-		mn.mc_top--;
-		rc = mdb_node_add(&mn, mn.mc_ki[ptop], &sepkey, NULL, rp->mp_pgno, 0);
-		mn.mc_top++;
-	}
-	if (rc != MDB_SUCCESS) {
-		goto done;
-	}
-	if (nflags & MDB_APPEND) {
-		mc->mc_pg[mc->mc_top] = rp;
-		mc->mc_ki[mc->mc_top] = 0;
-		rc = mdb_node_add(mc, 0, newkey, newdata, newpgno, nflags);
-		if (rc)
-			goto done;
-		for (i=0; i<mc->mc_top; i++)
-			mc->mc_ki[i] = mn.mc_ki[i];
-	} else if (!IS_LEAF2(mp)) {
-		/* Move nodes */
-		mc->mc_pg[mc->mc_top] = rp;
-		i = split_indx;
-		j = 0;
-		do {
-			if (i == newindx) {
-				rkey.mv_data = newkey->mv_data;
-				rkey.mv_size = newkey->mv_size;
-				if (IS_LEAF(mp)) {
-					rdata = newdata;
-				} else
-					pgno = newpgno;
-				flags = nflags;
-				/* Update index for the new key. */
-				mc->mc_ki[mc->mc_top] = j;
-			} else {
-				node = (MDB_node *)((char *)mp + copy->mp_ptrs[i] + PAGEBASE);
-				rkey.mv_data = NODEKEY(node);
-				rkey.mv_size = node->mn_ksize;
-				if (IS_LEAF(mp)) {
-					xdata.mv_data = NODEDATA(node);
-					xdata.mv_size = NODEDSZ(node);
-					rdata = &xdata;
-				} else
-					pgno = NODEPGNO(node);
-				flags = node->mn_flags;
-			}
-
-			if (!IS_LEAF(mp) && j == 0) {
-				/* First branch index doesn't need key data. */
-				rkey.mv_size = 0;
-			}
-
-			rc = mdb_node_add(mc, j, &rkey, rdata, pgno, flags);
-			if (rc)
-				goto done;
-			if (i == nkeys) {
-				i = 0;
-				j = 0;
-				mc->mc_pg[mc->mc_top] = copy;
-			} else {
-				i++;
-				j++;
-			}
-		} while (i != split_indx);
-
-		nkeys = NUMKEYS(copy);
-		for (i=0; i<nkeys; i++)
-			mp->mp_ptrs[i] = copy->mp_ptrs[i];
-		mp->mp_lower = copy->mp_lower;
-		mp->mp_upper = copy->mp_upper;
-		memcpy(NODEPTR(mp, nkeys-1), NODEPTR(copy, nkeys-1),
-			env->me_psize - copy->mp_upper - PAGEBASE);
-
-		/* reset back to original page */
-		if (newindx < split_indx) {
-			mc->mc_pg[mc->mc_top] = mp;
-		} else {
-			mc->mc_pg[mc->mc_top] = rp;
-			mc->mc_ki[ptop]++;
-			/* Make sure mc_ki is still valid.
-			 */
-			if (mn.mc_pg[ptop] != mc->mc_pg[ptop] &&
-				mc->mc_ki[ptop] >= NUMKEYS(mc->mc_pg[ptop])) {
-				for (i=0; i<=ptop; i++) {
-					mc->mc_pg[i] = mn.mc_pg[i];
-					mc->mc_ki[i] = mn.mc_ki[i];
-				}
-			}
-		}
-		if (nflags & MDB_RESERVE) {
-			node = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
-			if (!(node->mn_flags & F_BIGDATA))
-				newdata->mv_data = NODEDATA(node);
-		}
-	} else {
-		if (newindx >= split_indx) {
-			mc->mc_pg[mc->mc_top] = rp;
-			mc->mc_ki[ptop]++;
-			/* Make sure mc_ki is still valid.
-			 */
-			if (mn.mc_pg[ptop] != mc->mc_pg[ptop] &&
-				mc->mc_ki[ptop] >= NUMKEYS(mc->mc_pg[ptop])) {
-				for (i=0; i<=ptop; i++) {
-					mc->mc_pg[i] = mn.mc_pg[i];
-					mc->mc_ki[i] = mn.mc_ki[i];
-				}
-			}
-		}
-	}
-
-	{
-		/* Adjust other cursors pointing to mp */
-		MDB_cursor *m2, *m3;
-		MDB_dbi dbi = mc->mc_dbi;
-		nkeys = NUMKEYS(mp);
-
-		for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
-			if (mc->mc_flags & C_SUB)
-				m3 = &m2->mc_xcursor->mx_cursor;
-			else
-				m3 = m2;
-			if (m3 == mc)
-				continue;
-			if (!(m2->mc_flags & m3->mc_flags & C_INITIALIZED))
-				continue;
-			if (new_root) {
-				int k;
-				/* sub cursors may be on different DB */
-				if (m3->mc_pg[0] != mp)
-					continue;
-				/* root split */
-				for (k=new_root; k>=0; k--) {
-					m3->mc_ki[k+1] = m3->mc_ki[k];
-					m3->mc_pg[k+1] = m3->mc_pg[k];
-				}
-				if (m3->mc_ki[0] >= nkeys) {
-					m3->mc_ki[0] = 1;
-				} else {
-					m3->mc_ki[0] = 0;
-				}
-				m3->mc_pg[0] = mc->mc_pg[0];
-				m3->mc_snum++;
-				m3->mc_top++;
-			}
-			if (m3->mc_top >= mc->mc_top && m3->mc_pg[mc->mc_top] == mp) {
-				if (m3->mc_ki[mc->mc_top] >= newindx && !(nflags & MDB_SPLIT_REPLACE))
-					m3->mc_ki[mc->mc_top]++;
-				if (m3->mc_ki[mc->mc_top] >= nkeys) {
-					m3->mc_pg[mc->mc_top] = rp;
-					m3->mc_ki[mc->mc_top] -= nkeys;
-					for (i=0; i<mc->mc_top; i++) {
-						m3->mc_ki[i] = mn.mc_ki[i];
-						m3->mc_pg[i] = mn.mc_pg[i];
-					}
-				}
-			} else if (!did_split && m3->mc_top >= ptop && m3->mc_pg[ptop] == mc->mc_pg[ptop] &&
-				m3->mc_ki[ptop] >= mc->mc_ki[ptop]) {
-				m3->mc_ki[ptop]++;
-			}
-			if (m3->mc_xcursor && (m3->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED) &&
-				IS_LEAF(mp)) {
-				MDB_node *node = NODEPTR(m3->mc_pg[mc->mc_top], m3->mc_ki[mc->mc_top]);
-				if ((node->mn_flags & (F_DUPDATA|F_SUBDATA)) == F_DUPDATA)
-					m3->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(node);
-			}
-		}
-	}
-	DPRINTF(("mp left: %d, rp left: %d", SIZELEFT(mp), SIZELEFT(rp)));
-
-done:
-	if (copy)					/* tmp page */
-		mdb_page_free(env, copy);
-	if (rc)
-		mc->mc_txn->mt_flags |= MDB_TXN_ERROR;
-	return rc;
-}
-
-int
-mdb_put(MDB_txn *txn, MDB_dbi dbi,
-    MDB_val *key, MDB_val *data, unsigned int flags)
-{
-	MDB_cursor mc;
-	MDB_xcursor mx;
-	int rc;
-
-	if (!key || !data || !TXN_DBI_EXIST(txn, dbi, DB_USRVALID))
-		return EINVAL;
-
-	if (flags & ~(MDB_NOOVERWRITE|MDB_NODUPDATA|MDB_RESERVE|MDB_APPEND|MDB_APPENDDUP))
-		return EINVAL;
-
-	if (txn->mt_flags & (MDB_TXN_RDONLY|MDB_TXN_BLOCKED))
-		return (txn->mt_flags & MDB_TXN_RDONLY) ? EACCES : MDB_BAD_TXN;
-
-	mdb_cursor_init(&mc, txn, dbi, &mx);
-	mc.mc_next = txn->mt_cursors[dbi];
-	txn->mt_cursors[dbi] = &mc;
-	rc = mdb_cursor_put(&mc, key, data, flags);
-	txn->mt_cursors[dbi] = mc.mc_next;
-	return rc;
-}
-
-#ifndef MDB_WBUF
-#define MDB_WBUF	(1024*1024)
-#endif
-
-	/** State needed for a compacting copy. */
-typedef struct mdb_copy {
-	pthread_mutex_t mc_mutex;
-	pthread_cond_t mc_cond;
-	char *mc_wbuf[2];
-	char *mc_over[2];
-	MDB_env *mc_env;
-	MDB_txn *mc_txn;
-	int mc_wlen[2];
-	int mc_olen[2];
-	pgno_t mc_next_pgno;
-	HANDLE mc_fd;
-	int mc_status;
-	volatile int mc_new;
-	int mc_toggle;
-
-} mdb_copy;
-
-	/** Dedicated writer thread for compacting copy. */
-static THREAD_RET ESECT CALL_CONV
-mdb_env_copythr(void *arg)
-{
-	mdb_copy *my = arg;
-	char *ptr;
-	int toggle = 0, wsize, rc;
-#ifdef _WIN32
-	DWORD len;
-#define DO_WRITE(rc, fd, ptr, w2, len)	rc = WriteFile(fd, ptr, w2, &len, NULL)
-#else
-	int len;
-#define DO_WRITE(rc, fd, ptr, w2, len)	len = write(fd, ptr, w2); rc = (len >= 0)
-#endif
-
-	pthread_mutex_lock(&my->mc_mutex);
-	my->mc_new = 0;
-	pthread_cond_signal(&my->mc_cond);
-	for(;;) {
-		while (!my->mc_new)
-			pthread_cond_wait(&my->mc_cond, &my->mc_mutex);
-		if (my->mc_new < 0) {
-			my->mc_new = 0;
-			break;
-		}
-		my->mc_new = 0;
-		wsize = my->mc_wlen[toggle];
-		ptr = my->mc_wbuf[toggle];
-again:
-		while (wsize > 0) {
-			DO_WRITE(rc, my->mc_fd, ptr, wsize, len);
-			if (!rc) {
-				rc = ErrCode();
-				break;
-			} else if (len > 0) {
-				rc = MDB_SUCCESS;
-				ptr += len;
-				wsize -= len;
-				continue;
-			} else {
-				rc = EIO;
-				break;
-			}
-		}
-		if (rc) {
-			my->mc_status = rc;
-			break;
-		}
-		/* If there's an overflow page tail, write it too */
-		if (my->mc_olen[toggle]) {
-			wsize = my->mc_olen[toggle];
-			ptr = my->mc_over[toggle];
-			my->mc_olen[toggle] = 0;
-			goto again;
-		}
-		my->mc_wlen[toggle] = 0;
-		toggle ^= 1;
-		pthread_cond_signal(&my->mc_cond);
-	}
-	pthread_cond_signal(&my->mc_cond);
-	pthread_mutex_unlock(&my->mc_mutex);
-	return (THREAD_RET)0;
-#undef DO_WRITE
-}
-
-	/** Tell the writer thread there's a buffer ready to write */
-static int ESECT
-mdb_env_cthr_toggle(mdb_copy *my, int st)
-{
-	int toggle = my->mc_toggle ^ 1;
-	pthread_mutex_lock(&my->mc_mutex);
-	if (my->mc_status) {
-		pthread_mutex_unlock(&my->mc_mutex);
-		return my->mc_status;
-	}
-	while (my->mc_new == 1)
-		pthread_cond_wait(&my->mc_cond, &my->mc_mutex);
-	my->mc_new = st;
-	my->mc_toggle = toggle;
-	pthread_cond_signal(&my->mc_cond);
-	pthread_mutex_unlock(&my->mc_mutex);
-	return 0;
-}
-
-	/** Depth-first tree traversal for compacting copy. */
-static int ESECT
-mdb_env_cwalk(mdb_copy *my, pgno_t *pg, int flags)
-{
-	MDB_cursor mc;
-	MDB_node *ni;
-	MDB_page *mo, *mp, *leaf;
-	char *buf, *ptr;
-	int rc, toggle;
-	unsigned int i;
-
-	/* Empty DB, nothing to do */
-	if (*pg == P_INVALID)
-		return MDB_SUCCESS;
-
-	mc.mc_snum = 1;
-	mc.mc_top = 0;
-	mc.mc_txn = my->mc_txn;
-
-	rc = mdb_page_get(&mc, *pg, &mc.mc_pg[0], NULL);
-	if (rc)
-		return rc;
-	rc = mdb_page_search_root(&mc, NULL, MDB_PS_FIRST);
-	if (rc)
-		return rc;
-
-	/* Make cursor pages writable */
-	buf = ptr = malloc(my->mc_env->me_psize * mc.mc_snum);
-	if (buf == NULL)
-		return ENOMEM;
-
-	for (i=0; i<mc.mc_top; i++) {
-		mdb_page_copy((MDB_page *)ptr, mc.mc_pg[i], my->mc_env->me_psize);
-		mc.mc_pg[i] = (MDB_page *)ptr;
-		ptr += my->mc_env->me_psize;
-	}
-
-	/* This is writable space for a leaf page. Usually not needed. */
-	leaf = (MDB_page *)ptr;
-
-	toggle = my->mc_toggle;
-	while (mc.mc_snum > 0) {
-		unsigned n;
-		mp = mc.mc_pg[mc.mc_top];
-		n = NUMKEYS(mp);
-
-		if (IS_LEAF(mp)) {
-			if (!IS_LEAF2(mp) && !(flags & F_DUPDATA)) {
-				for (i=0; i<n; i++) {
-					ni = NODEPTR(mp, i);
-					if (ni->mn_flags & F_BIGDATA) {
-						MDB_page *omp;
-						pgno_t pg;
-
-						/* Need writable leaf */
-						if (mp != leaf) {
-							mc.mc_pg[mc.mc_top] = leaf;
-							mdb_page_copy(leaf, mp, my->mc_env->me_psize);
-							mp = leaf;
-							ni = NODEPTR(mp, i);
-						}
-
-						memcpy(&pg, NODEDATA(ni), sizeof(pg));
-						rc = mdb_page_get(&mc, pg, &omp, NULL);
-						if (rc)
-							goto done;
-						if (my->mc_wlen[toggle] >= MDB_WBUF) {
-							rc = mdb_env_cthr_toggle(my, 1);
-							if (rc)
-								goto done;
-							toggle = my->mc_toggle;
-						}
-						mo = (MDB_page *)(my->mc_wbuf[toggle] + my->mc_wlen[toggle]);
-						memcpy(mo, omp, my->mc_env->me_psize);
-						mo->mp_pgno = my->mc_next_pgno;
-						my->mc_next_pgno += omp->mp_pages;
-						my->mc_wlen[toggle] += my->mc_env->me_psize;
-						if (omp->mp_pages > 1) {
-							my->mc_olen[toggle] = my->mc_env->me_psize * (omp->mp_pages - 1);
-							my->mc_over[toggle] = (char *)omp + my->mc_env->me_psize;
-							rc = mdb_env_cthr_toggle(my, 1);
-							if (rc)
-								goto done;
-							toggle = my->mc_toggle;
-						}
-						memcpy(NODEDATA(ni), &mo->mp_pgno, sizeof(pgno_t));
-					} else if (ni->mn_flags & F_SUBDATA) {
-						MDB_db db;
-
-						/* Need writable leaf */
-						if (mp != leaf) {
-							mc.mc_pg[mc.mc_top] = leaf;
-							mdb_page_copy(leaf, mp, my->mc_env->me_psize);
-							mp = leaf;
-							ni = NODEPTR(mp, i);
-						}
-
-						memcpy(&db, NODEDATA(ni), sizeof(db));
-						my->mc_toggle = toggle;
-						rc = mdb_env_cwalk(my, &db.md_root, ni->mn_flags & F_DUPDATA);
-						if (rc)
-							goto done;
-						toggle = my->mc_toggle;
-						memcpy(NODEDATA(ni), &db, sizeof(db));
-					}
-				}
-			}
-		} else {
-			mc.mc_ki[mc.mc_top]++;
-			if (mc.mc_ki[mc.mc_top] < n) {
-				pgno_t pg;
-again:
-				ni = NODEPTR(mp, mc.mc_ki[mc.mc_top]);
-				pg = NODEPGNO(ni);
-				rc = mdb_page_get(&mc, pg, &mp, NULL);
-				if (rc)
-					goto done;
-				mc.mc_top++;
-				mc.mc_snum++;
-				mc.mc_ki[mc.mc_top] = 0;
-				if (IS_BRANCH(mp)) {
-					/* Whenever we advance to a sibling branch page,
-					 * we must proceed all the way down to its first leaf.
-					 */
-					mdb_page_copy(mc.mc_pg[mc.mc_top], mp, my->mc_env->me_psize);
-					goto again;
-				} else
-					mc.mc_pg[mc.mc_top] = mp;
-				continue;
-			}
-		}
-		if (my->mc_wlen[toggle] >= MDB_WBUF) {
-			rc = mdb_env_cthr_toggle(my, 1);
-			if (rc)
-				goto done;
-			toggle = my->mc_toggle;
-		}
-		mo = (MDB_page *)(my->mc_wbuf[toggle] + my->mc_wlen[toggle]);
-		mdb_page_copy(mo, mp, my->mc_env->me_psize);
-		mo->mp_pgno = my->mc_next_pgno++;
-		my->mc_wlen[toggle] += my->mc_env->me_psize;
-		if (mc.mc_top) {
-			/* Update parent if there is one */
-			ni = NODEPTR(mc.mc_pg[mc.mc_top-1], mc.mc_ki[mc.mc_top-1]);
-			SETPGNO(ni, mo->mp_pgno);
-			mdb_cursor_pop(&mc);
-		} else {
-			/* Otherwise we're done */
-			*pg = mo->mp_pgno;
-			break;
-		}
-	}
-done:
-	free(buf);
-	return rc;
-}
-
-	/** Copy environment with compaction. */
-static int ESECT
-mdb_env_copyfd1(MDB_env *env, HANDLE fd)
-{
-	MDB_meta *mm;
-	MDB_page *mp;
-	mdb_copy my;
-	MDB_txn *txn = NULL;
-	pthread_t thr;
-	int rc;
-
-#ifdef _WIN32
-	my.mc_mutex = CreateMutex(NULL, FALSE, NULL);
-	my.mc_cond = CreateEvent(NULL, FALSE, FALSE, NULL);
-	my.mc_wbuf[0] = _aligned_malloc(MDB_WBUF*2, env->me_os_psize);
-	if (my.mc_wbuf[0] == NULL)
-		return errno;
-#else
-	pthread_mutex_init(&my.mc_mutex, NULL);
-	pthread_cond_init(&my.mc_cond, NULL);
-#ifdef HAVE_MEMALIGN
-	my.mc_wbuf[0] = memalign(env->me_os_psize, MDB_WBUF*2);
-	if (my.mc_wbuf[0] == NULL)
-		return errno;
-#else
-	rc = posix_memalign((void **)&my.mc_wbuf[0], env->me_os_psize, MDB_WBUF*2);
-	if (rc)
-		return rc;
-#endif
-#endif
-	memset(my.mc_wbuf[0], 0, MDB_WBUF*2);
-	my.mc_wbuf[1] = my.mc_wbuf[0] + MDB_WBUF;
-	my.mc_wlen[0] = 0;
-	my.mc_wlen[1] = 0;
-	my.mc_olen[0] = 0;
-	my.mc_olen[1] = 0;
-	my.mc_next_pgno = NUM_METAS;
-	my.mc_status = 0;
-	my.mc_new = 1;
-	my.mc_toggle = 0;
-	my.mc_env = env;
-	my.mc_fd = fd;
-	THREAD_CREATE(thr, mdb_env_copythr, &my);
-
-	rc = mdb_txn_begin(env, NULL, MDB_RDONLY, &txn);
-	if (rc)
-		return rc;
-
-	mp = (MDB_page *)my.mc_wbuf[0];
-	memset(mp, 0, NUM_METAS * env->me_psize);
-	mp->mp_pgno = 0;
-	mp->mp_flags = P_META;
-	mm = (MDB_meta *)METADATA(mp);
-	mdb_env_init_meta0(env, mm);
-	mm->mm_address = env->me_metas[0]->mm_address;
-
-	mp = (MDB_page *)(my.mc_wbuf[0] + env->me_psize);
-	mp->mp_pgno = 1;
-	mp->mp_flags = P_META;
-	*(MDB_meta *)METADATA(mp) = *mm;
-	mm = (MDB_meta *)METADATA(mp);
-
-	/* Count the number of free pages, subtract from lastpg to find
-	 * number of active pages
-	 */
-	{
-		MDB_ID freecount = 0;
-		MDB_cursor mc;
-		MDB_val key, data;
-		mdb_cursor_init(&mc, txn, FREE_DBI, NULL);
-		while ((rc = mdb_cursor_get(&mc, &key, &data, MDB_NEXT)) == 0)
-			freecount += *(MDB_ID *)data.mv_data;
-		freecount += txn->mt_dbs[FREE_DBI].md_branch_pages +
-			txn->mt_dbs[FREE_DBI].md_leaf_pages +
-			txn->mt_dbs[FREE_DBI].md_overflow_pages;
-
-		/* Set metapage 1 */
-		mm->mm_last_pg = txn->mt_next_pgno - freecount - 1;
-		mm->mm_dbs[MAIN_DBI] = txn->mt_dbs[MAIN_DBI];
-		if (mm->mm_last_pg > NUM_METAS-1) {
-			mm->mm_dbs[MAIN_DBI].md_root = mm->mm_last_pg;
-			mm->mm_txnid = 1;
-		} else {
-			mm->mm_dbs[MAIN_DBI].md_root = P_INVALID;
-		}
-	}
-	my.mc_wlen[0] = env->me_psize * NUM_METAS;
-	my.mc_txn = txn;
-	pthread_mutex_lock(&my.mc_mutex);
-	while(my.mc_new)
-		pthread_cond_wait(&my.mc_cond, &my.mc_mutex);
-	pthread_mutex_unlock(&my.mc_mutex);
-	rc = mdb_env_cwalk(&my, &txn->mt_dbs[MAIN_DBI].md_root, 0);
-	if (rc == MDB_SUCCESS && my.mc_wlen[my.mc_toggle])
-		rc = mdb_env_cthr_toggle(&my, 1);
-	mdb_env_cthr_toggle(&my, -1);
-	pthread_mutex_lock(&my.mc_mutex);
-	while(my.mc_new)
-		pthread_cond_wait(&my.mc_cond, &my.mc_mutex);
-	pthread_mutex_unlock(&my.mc_mutex);
-	THREAD_FINISH(thr);
-
-	mdb_txn_abort(txn);
-#ifdef _WIN32
-	CloseHandle(my.mc_cond);
-	CloseHandle(my.mc_mutex);
-	_aligned_free(my.mc_wbuf[0]);
-#else
-	pthread_cond_destroy(&my.mc_cond);
-	pthread_mutex_destroy(&my.mc_mutex);
-	free(my.mc_wbuf[0]);
-#endif
-	return rc;
-}
-
-	/** Copy environment as-is. */
-static int ESECT
-mdb_env_copyfd0(MDB_env *env, HANDLE fd)
-{
-	MDB_txn *txn = NULL;
-	mdb_mutexref_t wmutex = NULL;
-	int rc;
-	mdb_size_t wsize, w3;
-	char *ptr;
-#ifdef _WIN32
-	DWORD len, w2;
-#define DO_WRITE(rc, fd, ptr, w2, len)	rc = WriteFile(fd, ptr, w2, &len, NULL)
-#else
-	ssize_t len;
-	size_t w2;
-#define DO_WRITE(rc, fd, ptr, w2, len)	len = write(fd, ptr, w2); rc = (len >= 0)
-#endif
-
-	/* Do the lock/unlock of the reader mutex before starting the
-	 * write txn.  Otherwise other read txns could block writers.
-	 */
-	rc = mdb_txn_begin(env, NULL, MDB_RDONLY, &txn);
-	if (rc)
-		return rc;
-
-	if (env->me_txns) {
-		/* We must start the actual read txn after blocking writers */
-		mdb_txn_end(txn, MDB_END_RESET_TMP);
-
-		/* Temporarily block writers until we snapshot the meta pages */
-		wmutex = env->me_wmutex;
-		if (LOCK_MUTEX(rc, env, wmutex))
-			goto leave;
-
-		rc = mdb_txn_renew0(txn);
-		if (rc) {
-			UNLOCK_MUTEX(wmutex);
-			goto leave;
-		}
-	}
-
-	wsize = env->me_psize * NUM_METAS;
-	ptr = env->me_map;
-	w2 = wsize;
-	while (w2 > 0) {
-		DO_WRITE(rc, fd, ptr, w2, len);
-		if (!rc) {
-			rc = ErrCode();
-			break;
-		} else if (len > 0) {
-			rc = MDB_SUCCESS;
-			ptr += len;
-			w2 -= len;
-			continue;
-		} else {
-			/* Non-blocking or async handles are not supported */
-			rc = EIO;
-			break;
-		}
-	}
-	if (wmutex)
-		UNLOCK_MUTEX(wmutex);
-
-	if (rc)
-		goto leave;
-
-	w3 = txn->mt_next_pgno * env->me_psize;
-	{
-		mdb_size_t fsize = 0;
-		if ((rc = mdb_fsize(env->me_fd, &fsize)))
-			goto leave;
-		if (w3 > fsize)
-			w3 = fsize;
-	}
-	wsize = w3 - wsize;
-	while (wsize > 0) {
-		if (wsize > MAX_WRITE)
-			w2 = MAX_WRITE;
-		else
-			w2 = wsize;
-		DO_WRITE(rc, fd, ptr, w2, len);
-		if (!rc) {
-			rc = ErrCode();
-			break;
-		} else if (len > 0) {
-			rc = MDB_SUCCESS;
-			ptr += len;
-			wsize -= len;
-			continue;
-		} else {
-			rc = EIO;
-			break;
-		}
-	}
-
-leave:
-	mdb_txn_abort(txn);
-	return rc;
-}
-
-int ESECT
-mdb_env_copyfd2(MDB_env *env, HANDLE fd, unsigned int flags)
-{
-	if (flags & MDB_CP_COMPACT)
-		return mdb_env_copyfd1(env, fd);
-	else
-		return mdb_env_copyfd0(env, fd);
-}
-
-int ESECT
-mdb_env_copyfd(MDB_env *env, HANDLE fd)
-{
-	return mdb_env_copyfd2(env, fd, 0);
-}
-
-int ESECT
-mdb_env_copy2(MDB_env *env, const char *path, unsigned int flags)
-{
-	int rc, len;
-	char *lpath;
-	HANDLE newfd = INVALID_HANDLE_VALUE;
-#ifdef _WIN32
-	wchar_t *wpath;
-#endif
-
-	if (env->me_flags & MDB_NOSUBDIR) {
-		lpath = (char *)path;
-	} else {
-		len = strlen(path);
-		len += sizeof(DATANAME);
-		lpath = malloc(len);
-		if (!lpath)
-			return ENOMEM;
-		sprintf(lpath, "%s" DATANAME, path);
-	}
-
-	/* The destination path must exist, but the destination file must not.
-	 * We don't want the OS to cache the writes, since the source data is
-	 * already in the OS cache.
-	 */
-#ifdef _WIN32
-	rc = utf8_to_utf16(lpath, -1, &wpath, NULL);
-	if (rc)
-		goto leave;
-	newfd = CreateFileW(wpath, GENERIC_WRITE, 0, NULL, CREATE_NEW,
-				FILE_FLAG_NO_BUFFERING|FILE_FLAG_WRITE_THROUGH, NULL);
-	free(wpath);
-#else
-	newfd = open(lpath, O_WRONLY|O_CREAT|O_EXCL, 0666);
-#endif
-	if (newfd == INVALID_HANDLE_VALUE) {
-		rc = ErrCode();
-		goto leave;
-	}
-
-	if (env->me_psize >= env->me_os_psize) {
-#ifdef O_DIRECT
-	/* Set O_DIRECT if the file system supports it */
-	if ((rc = fcntl(newfd, F_GETFL)) != -1)
-		(void) fcntl(newfd, F_SETFL, rc | O_DIRECT);
-#endif
-#ifdef F_NOCACHE	/* __APPLE__ */
-	rc = fcntl(newfd, F_NOCACHE, 1);
-	if (rc) {
-		rc = ErrCode();
-		goto leave;
-	}
-#endif
-	}
-
-	rc = mdb_env_copyfd2(env, newfd, flags);
-
-leave:
-	if (!(env->me_flags & MDB_NOSUBDIR))
-		free(lpath);
-	if (newfd != INVALID_HANDLE_VALUE)
-		if (close(newfd) < 0 && rc == MDB_SUCCESS)
-			rc = ErrCode();
-
-	return rc;
-}
-
-int ESECT
-mdb_env_copy(MDB_env *env, const char *path)
-{
-	return mdb_env_copy2(env, path, 0);
-}
-
-int ESECT
-mdb_env_set_flags(MDB_env *env, unsigned int flag, int onoff)
-{
-	if (flag & ~CHANGEABLE)
-		return EINVAL;
-	if (onoff)
-		env->me_flags |= flag;
-	else
-		env->me_flags &= ~flag;
-	return MDB_SUCCESS;
-}
-
-int ESECT
-mdb_env_get_flags(MDB_env *env, unsigned int *arg)
-{
-	if (!env || !arg)
-		return EINVAL;
-
-	*arg = env->me_flags & (CHANGEABLE|CHANGELESS);
-	return MDB_SUCCESS;
-}
-
-int ESECT
-mdb_env_set_userctx(MDB_env *env, void *ctx)
-{
-	if (!env)
-		return EINVAL;
-	env->me_userctx = ctx;
-	return MDB_SUCCESS;
-}
-
-void * ESECT
-mdb_env_get_userctx(MDB_env *env)
-{
-	return env ? env->me_userctx : NULL;
-}
-
-int ESECT
-mdb_env_set_assert(MDB_env *env, MDB_assert_func *func)
-{
-	if (!env)
-		return EINVAL;
-#ifndef NDEBUG
-	env->me_assert_func = func;
-#endif
-	return MDB_SUCCESS;
-}
-
-int ESECT
-mdb_env_get_path(MDB_env *env, const char **arg)
-{
-	if (!env || !arg)
-		return EINVAL;
-
-	*arg = env->me_path;
-	return MDB_SUCCESS;
-}
-
-int ESECT
-mdb_env_get_fd(MDB_env *env, mdb_filehandle_t *arg)
-{
-	if (!env || !arg)
-		return EINVAL;
-
-	*arg = env->me_fd;
-	return MDB_SUCCESS;
-}
-
-/** Common code for #mdb_stat() and #mdb_env_stat().
- * @param[in] env the environment to operate in.
- * @param[in] db the #MDB_db record containing the stats to return.
- * @param[out] arg the address of an #MDB_stat structure to receive the stats.
- * @return 0, this function always succeeds.
- */
-static int ESECT
-mdb_stat0(MDB_env *env, MDB_db *db, MDB_stat *arg)
-{
-	arg->ms_psize = env->me_psize;
-	arg->ms_depth = db->md_depth;
-	arg->ms_branch_pages = db->md_branch_pages;
-	arg->ms_leaf_pages = db->md_leaf_pages;
-	arg->ms_overflow_pages = db->md_overflow_pages;
-	arg->ms_entries = db->md_entries;
-
-	return MDB_SUCCESS;
-}
-
-int ESECT
-mdb_env_stat(MDB_env *env, MDB_stat *arg)
-{
-	MDB_meta *meta;
-
-	if (env == NULL || arg == NULL)
-		return EINVAL;
-
-	meta = mdb_env_pick_meta(env);
-
-	return mdb_stat0(env, &meta->mm_dbs[MAIN_DBI], arg);
-}
-
-int ESECT
-mdb_env_info(MDB_env *env, MDB_envinfo *arg)
-{
-	MDB_meta *meta;
-
-	if (env == NULL || arg == NULL)
-		return EINVAL;
-
-	meta = mdb_env_pick_meta(env);
-	arg->me_mapaddr = meta->mm_address;
-	arg->me_last_pgno = meta->mm_last_pg;
-	arg->me_last_txnid = meta->mm_txnid;
-
-	arg->me_mapsize = env->me_mapsize;
-	arg->me_maxreaders = env->me_maxreaders;
-	arg->me_numreaders = env->me_txns ? env->me_txns->mti_numreaders : 0;
-	return MDB_SUCCESS;
-}
-
-/** Set the default comparison functions for a database.
- * Called immediately after a database is opened to set the defaults.
- * The user can then override them with #mdb_set_compare() or
- * #mdb_set_dupsort().
- * @param[in] txn A transaction handle returned by #mdb_txn_begin()
- * @param[in] dbi A database handle returned by #mdb_dbi_open()
- */
-static void
-mdb_default_cmp(MDB_txn *txn, MDB_dbi dbi)
-{
-	uint16_t f = txn->mt_dbs[dbi].md_flags;
-
-	txn->mt_dbxs[dbi].md_cmp =
-		(f & MDB_REVERSEKEY) ? mdb_cmp_memnr :
-		(f & MDB_INTEGERKEY) ? mdb_cmp_cint  : mdb_cmp_memn;
-
-	txn->mt_dbxs[dbi].md_dcmp =
-		!(f & MDB_DUPSORT) ? 0 :
-		((f & MDB_INTEGERDUP)
-		 ? ((f & MDB_DUPFIXED)   ? mdb_cmp_int   : mdb_cmp_cint)
-		 : ((f & MDB_REVERSEDUP) ? mdb_cmp_memnr : mdb_cmp_memn));
-}
-
-int mdb_dbi_open(MDB_txn *txn, const char *name, unsigned int flags, MDB_dbi *dbi)
-{
-	MDB_val key, data;
-	MDB_dbi i;
-	MDB_cursor mc;
-	MDB_db dummy;
-	int rc, dbflag, exact;
-	unsigned int unused = 0, seq;
-	char *namedup;
-	size_t len;
-
-	if (flags & ~VALID_FLAGS)
-		return EINVAL;
-	if (txn->mt_flags & MDB_TXN_BLOCKED)
-		return MDB_BAD_TXN;
-
-	/* main DB? */
-	if (!name) {
-		*dbi = MAIN_DBI;
-		if (flags & PERSISTENT_FLAGS) {
-			uint16_t f2 = flags & PERSISTENT_FLAGS;
-			/* make sure flag changes get committed */
-			if ((txn->mt_dbs[MAIN_DBI].md_flags | f2) != txn->mt_dbs[MAIN_DBI].md_flags) {
-				txn->mt_dbs[MAIN_DBI].md_flags |= f2;
-				txn->mt_flags |= MDB_TXN_DIRTY;
-			}
-		}
-		mdb_default_cmp(txn, MAIN_DBI);
-		return MDB_SUCCESS;
-	}
-
-	if (txn->mt_dbxs[MAIN_DBI].md_cmp == NULL) {
-		mdb_default_cmp(txn, MAIN_DBI);
-	}
-
-	/* Is the DB already open? */
-	len = strlen(name);
-	for (i=CORE_DBS; i<txn->mt_numdbs; i++) {
-		if (!txn->mt_dbxs[i].md_name.mv_size) {
-			/* Remember this free slot */
-			if (!unused) unused = i;
-			continue;
-		}
-		if (len == txn->mt_dbxs[i].md_name.mv_size &&
-			!strncmp(name, txn->mt_dbxs[i].md_name.mv_data, len)) {
-			*dbi = i;
-			return MDB_SUCCESS;
-		}
-	}
-
-	/* If no free slot and max hit, fail */
-	if (!unused && txn->mt_numdbs >= txn->mt_env->me_maxdbs)
-		return MDB_DBS_FULL;
-
-	/* Cannot mix named databases with some mainDB flags */
-	if (txn->mt_dbs[MAIN_DBI].md_flags & (MDB_DUPSORT|MDB_INTEGERKEY))
-		return (flags & MDB_CREATE) ? MDB_INCOMPATIBLE : MDB_NOTFOUND;
-
-	/* Find the DB info */
-	dbflag = DB_NEW|DB_VALID|DB_USRVALID;
-	exact = 0;
-	key.mv_size = len;
-	key.mv_data = (void *)name;
-	mdb_cursor_init(&mc, txn, MAIN_DBI, NULL);
-	rc = mdb_cursor_set(&mc, &key, &data, MDB_SET, &exact);
-	if (rc == MDB_SUCCESS) {
-		/* make sure this is actually a DB */
-		MDB_node *node = NODEPTR(mc.mc_pg[mc.mc_top], mc.mc_ki[mc.mc_top]);
-		if ((node->mn_flags & (F_DUPDATA|F_SUBDATA)) != F_SUBDATA)
-			return MDB_INCOMPATIBLE;
-	} else if (! (rc == MDB_NOTFOUND && (flags & MDB_CREATE))) {
-		return rc;
-	}
-
-	/* Done here so we cannot fail after creating a new DB */
-	if ((namedup = strdup(name)) == NULL)
-		return ENOMEM;
-
-	if (rc) {
-		/* MDB_NOTFOUND and MDB_CREATE: Create new DB */
-		data.mv_size = sizeof(MDB_db);
-		data.mv_data = &dummy;
-		memset(&dummy, 0, sizeof(dummy));
-		dummy.md_root = P_INVALID;
-		dummy.md_flags = flags & PERSISTENT_FLAGS;
-		rc = mdb_cursor_put(&mc, &key, &data, F_SUBDATA);
-		dbflag |= DB_DIRTY;
-	}
-
-	if (rc) {
-		free(namedup);
-	} else {
-		/* Got info, register DBI in this txn */
-		unsigned int slot = unused ? unused : txn->mt_numdbs;
-		txn->mt_dbxs[slot].md_name.mv_data = namedup;
-		txn->mt_dbxs[slot].md_name.mv_size = len;
-		txn->mt_dbxs[slot].md_rel = NULL;
-		txn->mt_dbflags[slot] = dbflag;
-		/* txn-> and env-> are the same in read txns, use
-		 * tmp variable to avoid undefined assignment
-		 */
-		seq = ++txn->mt_env->me_dbiseqs[slot];
-		txn->mt_dbiseqs[slot] = seq;
-
-		memcpy(&txn->mt_dbs[slot], data.mv_data, sizeof(MDB_db));
-		*dbi = slot;
-		mdb_default_cmp(txn, slot);
-		if (!unused) {
-			txn->mt_numdbs++;
-		}
-	}
-
-	return rc;
-}
-
-int ESECT
-mdb_stat(MDB_txn *txn, MDB_dbi dbi, MDB_stat *arg)
-{
-	if (!arg || !TXN_DBI_EXIST(txn, dbi, DB_VALID))
-		return EINVAL;
-
-	if (txn->mt_flags & MDB_TXN_BLOCKED)
-		return MDB_BAD_TXN;
-
-	if (txn->mt_dbflags[dbi] & DB_STALE) {
-		MDB_cursor mc;
-		MDB_xcursor mx;
-		/* Stale, must read the DB's root. cursor_init does it for us. */
-		mdb_cursor_init(&mc, txn, dbi, &mx);
-	}
-	return mdb_stat0(txn->mt_env, &txn->mt_dbs[dbi], arg);
-}
-
-void mdb_dbi_close(MDB_env *env, MDB_dbi dbi)
-{
-	char *ptr;
-	if (dbi < CORE_DBS || dbi >= env->me_maxdbs)
-		return;
-	ptr = env->me_dbxs[dbi].md_name.mv_data;
-	/* If there was no name, this was already closed */
-	if (ptr) {
-		env->me_dbxs[dbi].md_name.mv_data = NULL;
-		env->me_dbxs[dbi].md_name.mv_size = 0;
-		env->me_dbflags[dbi] = 0;
-		env->me_dbiseqs[dbi]++;
-		free(ptr);
-	}
-}
-
-int mdb_dbi_flags(MDB_txn *txn, MDB_dbi dbi, unsigned int *flags)
-{
-	/* We could return the flags for the FREE_DBI too but what's the point? */
-	if (!TXN_DBI_EXIST(txn, dbi, DB_USRVALID))
-		return EINVAL;
-	*flags = txn->mt_dbs[dbi].md_flags & PERSISTENT_FLAGS;
-	return MDB_SUCCESS;
-}
-
-/** Add all the DB's pages to the free list.
- * @param[in] mc Cursor on the DB to free.
- * @param[in] subs non-Zero to check for sub-DBs in this DB.
- * @return 0 on success, non-zero on failure.
- */
-static int
-mdb_drop0(MDB_cursor *mc, int subs)
-{
-	int rc;
-
-	rc = mdb_page_search(mc, NULL, MDB_PS_FIRST);
-	if (rc == MDB_SUCCESS) {
-		MDB_txn *txn = mc->mc_txn;
-		MDB_node *ni;
-		MDB_cursor mx;
-		unsigned int i;
-
-		/* DUPSORT sub-DBs have no ovpages/DBs. Omit scanning leaves.
-		 * This also avoids any P_LEAF2 pages, which have no nodes.
-		 * Also if the DB doesn't have sub-DBs and has no overflow
-		 * pages, omit scanning leaves.
-		 */
-		if ((mc->mc_flags & C_SUB) ||
-			(!subs && !mc->mc_db->md_overflow_pages))
-			mdb_cursor_pop(mc);
-
-		mdb_cursor_copy(mc, &mx);
-#ifdef MDB_VL32
-		/* bump refcount for mx's pages */
-		for (i=0; i<mc->mc_snum; i++)
-			mdb_page_get(&mx, mc->mc_pg[i]->mp_pgno, &mx.mc_pg[i], NULL);
-#endif
-		while (mc->mc_snum > 0) {
-			MDB_page *mp = mc->mc_pg[mc->mc_top];
-			unsigned n = NUMKEYS(mp);
-			if (IS_LEAF(mp)) {
-				for (i=0; i<n; i++) {
-					ni = NODEPTR(mp, i);
-					if (ni->mn_flags & F_BIGDATA) {
-						MDB_page *omp;
-						pgno_t pg;
-						memcpy(&pg, NODEDATA(ni), sizeof(pg));
-						rc = mdb_page_get(mc, pg, &omp, NULL);
-						if (rc != 0)
-							goto done;
-						mdb_cassert(mc, IS_OVERFLOW(omp));
-						rc = mdb_midl_append_range(&txn->mt_free_pgs,
-							pg, omp->mp_pages);
-						if (rc)
-							goto done;
-						mc->mc_db->md_overflow_pages -= omp->mp_pages;
-						if (!mc->mc_db->md_overflow_pages && !subs)
-							break;
-					} else if (subs && (ni->mn_flags & F_SUBDATA)) {
-						mdb_xcursor_init1(mc, ni);
-						rc = mdb_drop0(&mc->mc_xcursor->mx_cursor, 0);
-						if (rc)
-							goto done;
-					}
-				}
-				if (!subs && !mc->mc_db->md_overflow_pages)
-					goto pop;
-			} else {
-				if ((rc = mdb_midl_need(&txn->mt_free_pgs, n)) != 0)
-					goto done;
-				for (i=0; i<n; i++) {
-					pgno_t pg;
-					ni = NODEPTR(mp, i);
-					pg = NODEPGNO(ni);
-					/* free it */
-					mdb_midl_xappend(txn->mt_free_pgs, pg);
-				}
-			}
-			if (!mc->mc_top)
-				break;
-			mc->mc_ki[mc->mc_top] = i;
-			rc = mdb_cursor_sibling(mc, 1);
-			if (rc) {
-				if (rc != MDB_NOTFOUND)
-					goto done;
-				/* no more siblings, go back to beginning
-				 * of previous level.
-				 */
-pop:
-				mdb_cursor_pop(mc);
-				mc->mc_ki[0] = 0;
-				for (i=1; i<mc->mc_snum; i++) {
-					mc->mc_ki[i] = 0;
-					mc->mc_pg[i] = mx.mc_pg[i];
-				}
-			}
-		}
-		/* free it */
-		rc = mdb_midl_append(&txn->mt_free_pgs, mc->mc_db->md_root);
-done:
-		if (rc)
-			txn->mt_flags |= MDB_TXN_ERROR;
-#ifdef MDB_VL32
-		/* drop refcount for mx's pages */
-		mdb_cursor_unref(&mx);
-#endif
-	} else if (rc == MDB_NOTFOUND) {
-		rc = MDB_SUCCESS;
-	}
-	mc->mc_flags &= ~C_INITIALIZED;
-	return rc;
-}
-
-int mdb_drop(MDB_txn *txn, MDB_dbi dbi, int del)
-{
-	MDB_cursor *mc, *m2;
-	int rc;
-
-	if ((unsigned)del > 1 || !TXN_DBI_EXIST(txn, dbi, DB_USRVALID))
-		return EINVAL;
-
-	if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY))
-		return EACCES;
-
-	if (TXN_DBI_CHANGED(txn, dbi))
-		return MDB_BAD_DBI;
-
-	rc = mdb_cursor_open(txn, dbi, &mc);
-	if (rc)
-		return rc;
-
-	rc = mdb_drop0(mc, mc->mc_db->md_flags & MDB_DUPSORT);
-	/* Invalidate the dropped DB's cursors */
-	for (m2 = txn->mt_cursors[dbi]; m2; m2 = m2->mc_next)
-		m2->mc_flags &= ~(C_INITIALIZED|C_EOF);
-	if (rc)
-		goto leave;
-
-	/* Can't delete the main DB */
-	if (del && dbi >= CORE_DBS) {
-		rc = mdb_del0(txn, MAIN_DBI, &mc->mc_dbx->md_name, NULL, F_SUBDATA);
-		if (!rc) {
-			txn->mt_dbflags[dbi] = DB_STALE;
-			mdb_dbi_close(txn->mt_env, dbi);
-		} else {
-			txn->mt_flags |= MDB_TXN_ERROR;
-		}
-	} else {
-		/* reset the DB record, mark it dirty */
-		txn->mt_dbflags[dbi] |= DB_DIRTY;
-		txn->mt_dbs[dbi].md_depth = 0;
-		txn->mt_dbs[dbi].md_branch_pages = 0;
-		txn->mt_dbs[dbi].md_leaf_pages = 0;
-		txn->mt_dbs[dbi].md_overflow_pages = 0;
-		txn->mt_dbs[dbi].md_entries = 0;
-		txn->mt_dbs[dbi].md_root = P_INVALID;
-
-		txn->mt_flags |= MDB_TXN_DIRTY;
-	}
-leave:
-	mdb_cursor_close(mc);
-	return rc;
-}
-
-int mdb_set_compare(MDB_txn *txn, MDB_dbi dbi, MDB_cmp_func *cmp)
-{
-	if (!TXN_DBI_EXIST(txn, dbi, DB_USRVALID))
-		return EINVAL;
-
-	txn->mt_dbxs[dbi].md_cmp = cmp;
-	return MDB_SUCCESS;
-}
-
-int mdb_set_dupsort(MDB_txn *txn, MDB_dbi dbi, MDB_cmp_func *cmp)
-{
-	if (!TXN_DBI_EXIST(txn, dbi, DB_USRVALID))
-		return EINVAL;
-
-	txn->mt_dbxs[dbi].md_dcmp = cmp;
-	return MDB_SUCCESS;
-}
-
-int mdb_set_relfunc(MDB_txn *txn, MDB_dbi dbi, MDB_rel_func *rel)
-{
-	if (!TXN_DBI_EXIST(txn, dbi, DB_USRVALID))
-		return EINVAL;
-
-	txn->mt_dbxs[dbi].md_rel = rel;
-	return MDB_SUCCESS;
-}
-
-int mdb_set_relctx(MDB_txn *txn, MDB_dbi dbi, void *ctx)
-{
-	if (!TXN_DBI_EXIST(txn, dbi, DB_USRVALID))
-		return EINVAL;
-
-	txn->mt_dbxs[dbi].md_relctx = ctx;
-	return MDB_SUCCESS;
-}
-
-int ESECT
-mdb_env_get_maxkeysize(MDB_env *env)
-{
-	return ENV_MAXKEY(env);
-}
-
-int ESECT
-mdb_reader_list(MDB_env *env, MDB_msg_func *func, void *ctx)
-{
-	unsigned int i, rdrs;
-	MDB_reader *mr;
-	char buf[64];
-	int rc = 0, first = 1;
-
-	if (!env || !func)
-		return -1;
-	if (!env->me_txns) {
-		return func("(no reader locks)\n", ctx);
-	}
-	rdrs = env->me_txns->mti_numreaders;
-	mr = env->me_txns->mti_readers;
-	for (i=0; i<rdrs; i++) {
-		if (mr[i].mr_pid) {
-			txnid_t	txnid = mr[i].mr_txnid;
-			sprintf(buf, txnid == (txnid_t)-1 ?
-				"%10d %"Z"x -\n" : "%10d %"Z"x %"Y"u\n",
-				(int)mr[i].mr_pid, (size_t)mr[i].mr_tid, txnid);
-			if (first) {
-				first = 0;
-				rc = func("    pid     thread     txnid\n", ctx);
-				if (rc < 0)
-					break;
-			}
-			rc = func(buf, ctx);
-			if (rc < 0)
-				break;
-		}
-	}
-	if (first) {
-		rc = func("(no active readers)\n", ctx);
-	}
-	return rc;
-}
-
-/** Insert pid into list if not already present.
- * return -1 if already present.
- */
-static int ESECT
-mdb_pid_insert(MDB_PID_T *ids, MDB_PID_T pid)
-{
-	/* binary search of pid in list */
-	unsigned base = 0;
-	unsigned cursor = 1;
-	int val = 0;
-	unsigned n = ids[0];
-
-	while( 0 < n ) {
-		unsigned pivot = n >> 1;
-		cursor = base + pivot + 1;
-		val = pid - ids[cursor];
-
-		if( val < 0 ) {
-			n = pivot;
-
-		} else if ( val > 0 ) {
-			base = cursor;
-			n -= pivot + 1;
-
-		} else {
-			/* found, so it's a duplicate */
-			return -1;
-		}
-	}
-
-	if( val > 0 ) {
-		++cursor;
-	}
-	ids[0]++;
-	for (n = ids[0]; n > cursor; n--)
-		ids[n] = ids[n-1];
-	ids[n] = pid;
-	return 0;
-}
-
-int ESECT
-mdb_reader_check(MDB_env *env, int *dead)
-{
-	if (!env)
-		return EINVAL;
-	if (dead)
-		*dead = 0;
-	return env->me_txns ? mdb_reader_check0(env, 0, dead) : MDB_SUCCESS;
-}
-
-/** As #mdb_reader_check(). rlocked = <caller locked the reader mutex>. */
-static int ESECT
-mdb_reader_check0(MDB_env *env, int rlocked, int *dead)
-{
-	mdb_mutexref_t rmutex = rlocked ? NULL : env->me_rmutex;
-	unsigned int i, j, rdrs;
-	MDB_reader *mr;
-	MDB_PID_T *pids, pid;
-	int rc = MDB_SUCCESS, count = 0;
-
-	rdrs = env->me_txns->mti_numreaders;
-	pids = malloc((rdrs+1) * sizeof(MDB_PID_T));
-	if (!pids)
-		return ENOMEM;
-	pids[0] = 0;
-	mr = env->me_txns->mti_readers;
-	for (i=0; i<rdrs; i++) {
-		pid = mr[i].mr_pid;
-		if (pid && pid != env->me_pid) {
-			if (mdb_pid_insert(pids, pid) == 0) {
-				if (!mdb_reader_pid(env, Pidcheck, pid)) {
-					/* Stale reader found */
-					j = i;
-					if (rmutex) {
-						if ((rc = LOCK_MUTEX0(rmutex)) != 0) {
-							if ((rc = mdb_mutex_failed(env, rmutex, rc)))
-								break;
-							rdrs = 0; /* the above checked all readers */
-						} else {
-							/* Recheck, a new process may have reused pid */
-							if (mdb_reader_pid(env, Pidcheck, pid))
-								j = rdrs;
-						}
-					}
-					for (; j<rdrs; j++)
-							if (mr[j].mr_pid == pid) {
-								DPRINTF(("clear stale reader pid %u txn %"Y"d",
-									(unsigned) pid, mr[j].mr_txnid));
-								mr[j].mr_pid = 0;
-								count++;
-							}
-					if (rmutex)
-						UNLOCK_MUTEX(rmutex);
-				}
-			}
-		}
-	}
-	free(pids);
-	if (dead)
-		*dead = count;
-	return rc;
-}
-
-#ifdef MDB_ROBUST_SUPPORTED
-/** Handle #LOCK_MUTEX0() failure.
- * Try to repair the lock file if the mutex owner died.
- * @param[in] env	the environment handle
- * @param[in] mutex	LOCK_MUTEX0() mutex
- * @param[in] rc	LOCK_MUTEX0() error (nonzero)
- * @return 0 on success with the mutex locked, or an error code on failure.
- */
-static int ESECT
-mdb_mutex_failed(MDB_env *env, mdb_mutexref_t mutex, int rc)
-{
-	int rlocked, rc2;
-	MDB_meta *meta;
-
-	if (rc == MDB_OWNERDEAD) {
-		/* We own the mutex. Clean up after dead previous owner. */
-		rc = MDB_SUCCESS;
-		rlocked = (mutex == env->me_rmutex);
-		if (!rlocked) {
-			/* Keep mti_txnid updated, otherwise next writer can
-			 * overwrite data which latest meta page refers to.
-			 */
-			meta = mdb_env_pick_meta(env);
-			env->me_txns->mti_txnid = meta->mm_txnid;
-			/* env is hosed if the dead thread was ours */
-			if (env->me_txn) {
-				env->me_flags |= MDB_FATAL_ERROR;
-				env->me_txn = NULL;
-				rc = MDB_PANIC;
-			}
-		}
-		DPRINTF(("%cmutex owner died, %s", (rlocked ? 'r' : 'w'),
-			(rc ? "this process' env is hosed" : "recovering")));
-		rc2 = mdb_reader_check0(env, rlocked, NULL);
-		if (rc2 == 0)
-			rc2 = mdb_mutex_consistent(mutex);
-		if (rc || (rc = rc2)) {
-			DPRINTF(("LOCK_MUTEX recovery failed, %s", mdb_strerror(rc)));
-			UNLOCK_MUTEX(mutex);
-		}
-	} else {
-#ifdef _WIN32
-		rc = ErrCode();
-#endif
-		DPRINTF(("LOCK_MUTEX failed, %s", mdb_strerror(rc)));
-	}
-
-	return rc;
-}
-#endif	/* MDB_ROBUST_SUPPORTED */
-/** @} */
-
-#if defined(_WIN32)
-static int utf8_to_utf16(const char *src, int srcsize, wchar_t **dst, int *dstsize)
-{
-	int need;
-	wchar_t *result;
-	need = MultiByteToWideChar(CP_UTF8, 0, src, srcsize, NULL, 0);
-	if (need == 0xFFFD)
-		return EILSEQ;
-	if (need == 0)
-		return EINVAL;
-	result = malloc(sizeof(wchar_t) * need);
-	if (!result)
-		return ENOMEM;
-	MultiByteToWideChar(CP_UTF8, 0, src, srcsize, result, need);
-	if (dstsize)
-		*dstsize = need;
-	*dst = result;
-	return 0;
-}
-#endif /* defined(_WIN32) */
+#endif

+

+#pragma warning(disable: 4706)

+

+#if defined(MDB_VL32) || defined(__WIN64__)

+#define _FILE_OFFSET_BITS	64

+#endif

+#ifdef _WIN32

+#include <malloc.h>

+#include <windows.h>

+

+/* We use native NT APIs to setup the memory map, so that we can

+ * let the DB file grow incrementally instead of always preallocating

+ * the full size. These APIs are defined in <wdm.h> and <ntifs.h>

+ * but those headers are meant for driver-level development and

+ * conflict with the regular user-level headers, so we explicitly

+ * declare them here. Using these APIs also means we must link to

+ * ntdll.dll, which is not linked by default in user code.

+ */

+

+NTSTATUS WINAPI

+	NtCreateSection(OUT PHANDLE sh, IN ACCESS_MASK acc,

+	IN void * oa OPTIONAL,

+	IN PLARGE_INTEGER ms OPTIONAL,

+	IN ULONG pp, IN ULONG aa, IN HANDLE fh OPTIONAL);

+

+typedef enum _SECTION_INHERIT {

+	ViewShare = 1,

+	ViewUnmap = 2

+} SECTION_INHERIT;

+

+NTSTATUS WINAPI

+	NtMapViewOfSection(IN PHANDLE sh, IN HANDLE ph,

+	IN OUT PVOID *addr, IN ULONG_PTR zbits,

+	IN SIZE_T cs, IN OUT PLARGE_INTEGER off OPTIONAL,

+	IN OUT PSIZE_T vs, IN SECTION_INHERIT ih,

+	IN ULONG at, IN ULONG pp);

+

+NTSTATUS WINAPI

+	NtClose(HANDLE h);

+

+/** getpid() returns int; MinGW defines pid_t but MinGW64 typedefs it

+ *  as int64 which is wrong. MSVC doesn't define it at all, so just

+ *  don't use it.

+ */

+#define MDB_PID_T	int

+#define MDB_THR_T	DWORD

+#include <sys/types.h>

+#include <sys/stat.h>

+#ifdef __GNUC__

+# include <sys/param.h>

+#else

+# define LITTLE_ENDIAN	1234

+# define BIG_ENDIAN	4321

+# define BYTE_ORDER	LITTLE_ENDIAN

+# ifndef SSIZE_MAX

+#  define SSIZE_MAX	INT_MAX

+# endif

+#endif

+#else

+#include <sys/types.h>

+#include <sys/stat.h>

+#define MDB_PID_T	pid_t

+#define MDB_THR_T	pthread_t

+#include <sys/param.h>

+#include <sys/uio.h>

+#include <sys/mman.h>

+#ifdef HAVE_SYS_FILE_H

+#include <sys/file.h>

+#endif

+#include <fcntl.h>

+#endif

+

+#if defined(__mips) && defined(__linux)

+/* MIPS has cache coherency issues, requires explicit cache control */

+#include <asm/cachectl.h>

+extern int cacheflush(char *addr, int nbytes, int cache);

+#define CACHEFLUSH(addr, bytes, cache)	cacheflush(addr, bytes, cache)

+#else

+#define CACHEFLUSH(addr, bytes, cache)

+#endif

+

+#if defined(__linux) && !defined(MDB_FDATASYNC_WORKS)

+/** fdatasync is broken on ext3/ext4fs on older kernels, see

+ *	description in #mdb_env_open2 comments. You can safely

+ *	define MDB_FDATASYNC_WORKS if this code will only be run

+ *	on kernels 3.6 and newer.

+ */

+#define	BROKEN_FDATASYNC

+#endif

+

+#include <errno.h>

+#include <limits.h>

+#include <stddef.h>

+#include <inttypes.h>

+#include <stdio.h>

+#include <stdlib.h>

+#include <string.h>

+#include <time.h>

+

+#ifdef _MSC_VER

+#include <io.h>

+typedef SSIZE_T	ssize_t;

+#else

+#include <unistd.h>

+#endif

+

+#if defined(__sun) || defined(ANDROID)

+/* Most platforms have posix_memalign, older may only have memalign */

+#define HAVE_MEMALIGN	1

+#include <malloc.h>

+#endif

+

+#if !(defined(BYTE_ORDER) || defined(__BYTE_ORDER))

+#include <netinet/in.h>

+#include <resolv.h>	/* defines BYTE_ORDER on HPUX and Solaris */

+#endif

+

+#if defined(__APPLE__) || defined (BSD)

+# if !(defined(MDB_USE_POSIX_MUTEX) || defined(MDB_USE_POSIX_SEM))

+# define MDB_USE_SYSV_SEM	1

+# endif

+# define MDB_FDATASYNC		fsync

+#elif defined(ANDROID)

+# define MDB_FDATASYNC		fsync

+#endif

+

+#ifndef _WIN32

+#include <pthread.h>

+#ifdef MDB_USE_POSIX_SEM

+# define MDB_USE_HASH		1

+#include <semaphore.h>

+#elif defined(MDB_USE_SYSV_SEM)

+#include <sys/ipc.h>

+#include <sys/sem.h>

+#ifdef _SEM_SEMUN_UNDEFINED

+union semun {

+	int val;

+	struct semid_ds *buf;

+	unsigned short *array;

+};

+#endif /* _SEM_SEMUN_UNDEFINED */

+#else

+#define MDB_USE_POSIX_MUTEX	1

+#endif /* MDB_USE_POSIX_SEM */

+#endif /* !_WIN32 */

+

+#if defined(_WIN32) + defined(MDB_USE_POSIX_SEM) + defined(MDB_USE_SYSV_SEM) \

+	+ defined(MDB_USE_POSIX_MUTEX) != 1

+# error "Ambiguous shared-lock implementation"

+#endif

+

+#ifdef USE_VALGRIND

+#include <valgrind/memcheck.h>

+#define VGMEMP_CREATE(h,r,z)    VALGRIND_CREATE_MEMPOOL(h,r,z)

+#define VGMEMP_ALLOC(h,a,s) VALGRIND_MEMPOOL_ALLOC(h,a,s)

+#define VGMEMP_FREE(h,a) VALGRIND_MEMPOOL_FREE(h,a)

+#define VGMEMP_DESTROY(h)	VALGRIND_DESTROY_MEMPOOL(h)

+#define VGMEMP_DEFINED(a,s)	VALGRIND_MAKE_MEM_DEFINED(a,s)

+#else

+#define VGMEMP_CREATE(h,r,z)

+#define VGMEMP_ALLOC(h,a,s)

+#define VGMEMP_FREE(h,a)

+#define VGMEMP_DESTROY(h)

+#define VGMEMP_DEFINED(a,s)

+#endif

+

+#ifndef BYTE_ORDER

+# if (defined(_LITTLE_ENDIAN) || defined(_BIG_ENDIAN)) && !(defined(_LITTLE_ENDIAN) && defined(_BIG_ENDIAN))

+/* Solaris just defines one or the other */

+#  define LITTLE_ENDIAN	1234

+#  define BIG_ENDIAN	4321

+#  ifdef _LITTLE_ENDIAN

+#   define BYTE_ORDER  LITTLE_ENDIAN

+#  else

+#   define BYTE_ORDER  BIG_ENDIAN

+#  endif

+# else

+#  define BYTE_ORDER   __BYTE_ORDER

+# endif

+#endif

+

+#ifndef LITTLE_ENDIAN

+#define LITTLE_ENDIAN	__LITTLE_ENDIAN

+#endif

+#ifndef BIG_ENDIAN

+#define BIG_ENDIAN	__BIG_ENDIAN

+#endif

+

+#if defined(__i386) || defined(__x86_64) || defined(_M_IX86)

+#define MISALIGNED_OK	1

+#endif

+

+#include "lmdb.h"

+#include "midl.h"

+

+#if (BYTE_ORDER == LITTLE_ENDIAN) == (BYTE_ORDER == BIG_ENDIAN)

+# error "Unknown or unsupported endianness (BYTE_ORDER)"

+#elif (-6 & 5) || CHAR_BIT != 8 || UINT_MAX < 0xffffffff || ULONG_MAX % 0xFFFF

+# error "Two's complement, reasonably sized integer types, please"

+#endif

+

+#ifdef __GNUC__

+/** Put infrequently used env functions in separate section */

+# ifdef __APPLE__

+#  define	ESECT	__attribute__ ((section("__TEXT,text_env")))

+# else

+#  define	ESECT	__attribute__ ((section("text_env")))

+# endif

+#else

+#define ESECT

+#endif

+

+#ifdef _WIN32

+#define CALL_CONV WINAPI

+#else

+#define CALL_CONV

+#endif

+

+/** @defgroup internal	LMDB Internals

+ *	@{

+ */

+/** @defgroup compat	Compatibility Macros

+ *	A bunch of macros to minimize the amount of platform-specific ifdefs

+ *	needed throughout the rest of the code. When the features this library

+ *	needs are similar enough to POSIX to be hidden in a one-or-two line

+ *	replacement, this macro approach is used.

+ *	@{

+ */

+

+	/** Features under development */

+#ifndef MDB_DEVEL

+#define MDB_DEVEL 0

+#endif

+

+	/** Wrapper around __func__, which is a C99 feature */

+#if __STDC_VERSION__ >= 199901L

+# define mdb_func_	__func__

+#elif __GNUC__ >= 2 || _MSC_VER >= 1300

+# define mdb_func_	__FUNCTION__

+#else

+/* If a debug message says <mdb_unknown>(), update the #if statements above */

+# define mdb_func_	"<mdb_unknown>"

+#endif

+

+/* Internal error codes, not exposed outside liblmdb */

+#define	MDB_NO_ROOT		(MDB_LAST_ERRCODE + 10)

+#ifdef _WIN32

+#define MDB_OWNERDEAD	((int) WAIT_ABANDONED)

+#elif defined MDB_USE_SYSV_SEM

+#define MDB_OWNERDEAD	(MDB_LAST_ERRCODE + 11)

+#elif defined(MDB_USE_POSIX_MUTEX) && defined(EOWNERDEAD)

+#define MDB_OWNERDEAD	EOWNERDEAD	/**< #LOCK_MUTEX0() result if dead owner */

+#endif

+

+#ifdef __GLIBC__

+#define	GLIBC_VER	((__GLIBC__ << 16 )| __GLIBC_MINOR__)

+#endif

+/** Some platforms define the EOWNERDEAD error code

+ * even though they don't support Robust Mutexes.

+ * Compile with -DMDB_USE_ROBUST=0, or use some other

+ * mechanism like -DMDB_USE_SYSV_SEM instead of

+ * -DMDB_USE_POSIX_MUTEX. (SysV semaphores are

+ * also Robust, but some systems don't support them

+ * either.)

+ */

+#ifndef MDB_USE_ROBUST

+/* Android currently lacks Robust Mutex support. So does glibc < 2.4. */

+# if defined(MDB_USE_POSIX_MUTEX) && (defined(ANDROID) || \

+	(defined(__GLIBC__) && GLIBC_VER < 0x020004))

+#  define MDB_USE_ROBUST	0

+# else

+#  define MDB_USE_ROBUST	1

+/* glibc < 2.12 only provided _np API */

+#  if defined(__GLIBC__) && GLIBC_VER < 0x02000c

+#   define PTHREAD_MUTEX_ROBUST	PTHREAD_MUTEX_ROBUST_NP

+#   define pthread_mutexattr_setrobust(attr, flag)	pthread_mutexattr_setrobust_np(attr, flag)

+#   define pthread_mutex_consistent(mutex)	pthread_mutex_consistent_np(mutex)

+#  endif

+# endif

+#endif /* MDB_USE_ROBUST */

+

+#if defined(MDB_OWNERDEAD) && MDB_USE_ROBUST

+#define MDB_ROBUST_SUPPORTED	1

+#endif

+

+#ifdef _WIN32

+#define MDB_USE_HASH	1

+#define MDB_PIDLOCK	0

+#define THREAD_RET	DWORD

+#define pthread_t	HANDLE

+#define pthread_mutex_t	HANDLE

+#define pthread_cond_t	HANDLE

+typedef HANDLE mdb_mutex_t, mdb_mutexref_t;

+#define pthread_key_t	DWORD

+#define pthread_self()	GetCurrentThreadId()

+#define pthread_key_create(x,y)	\

+	((*(x) = TlsAlloc()) == TLS_OUT_OF_INDEXES ? ErrCode() : 0)

+#define pthread_key_delete(x)	TlsFree(x)

+#define pthread_getspecific(x)	TlsGetValue(x)

+#define pthread_setspecific(x,y)	(TlsSetValue(x,y) ? 0 : ErrCode())

+#define pthread_mutex_unlock(x)	ReleaseMutex(*x)

+#define pthread_mutex_lock(x)	WaitForSingleObject(*x, INFINITE)

+#define pthread_cond_signal(x)	SetEvent(*x)

+#define pthread_cond_wait(cond,mutex)	do{SignalObjectAndWait(*mutex, *cond, INFINITE, FALSE); WaitForSingleObject(*mutex, INFINITE);}while(0)

+#define THREAD_CREATE(thr,start,arg)	thr=CreateThread(NULL,0,start,arg,0,NULL)

+#define THREAD_FINISH(thr)	WaitForSingleObject(thr, INFINITE)

+#define LOCK_MUTEX0(mutex)		WaitForSingleObject(mutex, INFINITE)

+#define UNLOCK_MUTEX(mutex)		ReleaseMutex(mutex)

+#define mdb_mutex_consistent(mutex)	0

+#define getpid()	GetCurrentProcessId()

+#define	MDB_FDATASYNC(fd)	(!FlushFileBuffers(fd))

+#define	MDB_MSYNC(addr,len,flags)	(!FlushViewOfFile(addr,len))

+#define	ErrCode()	GetLastError()

+#define GET_PAGESIZE(x) {SYSTEM_INFO si; GetSystemInfo(&si); (x) = si.dwPageSize;}

+#define	close(fd)	(CloseHandle(fd) ? 0 : -1)

+#define	munmap(ptr,len)	UnmapViewOfFile(ptr)

+#ifdef PROCESS_QUERY_LIMITED_INFORMATION

+#define MDB_PROCESS_QUERY_LIMITED_INFORMATION PROCESS_QUERY_LIMITED_INFORMATION

+#else

+#define MDB_PROCESS_QUERY_LIMITED_INFORMATION 0x1000

+#endif

+#define	Z	"I"

+#else

+#define THREAD_RET	void *

+#define THREAD_CREATE(thr,start,arg)	pthread_create(&thr,NULL,start,arg)

+#define THREAD_FINISH(thr)	pthread_join(thr,NULL)

+#define	Z	"z"			/**< printf format modifier for size_t */

+

+	/** For MDB_LOCK_FORMAT: True if readers take a pid lock in the lockfile */

+#define MDB_PIDLOCK			1

+

+#ifdef MDB_USE_POSIX_SEM

+

+typedef sem_t *mdb_mutex_t, *mdb_mutexref_t;

+#define LOCK_MUTEX0(mutex)		mdb_sem_wait(mutex)

+#define UNLOCK_MUTEX(mutex)		sem_post(mutex)

+

+static int

+mdb_sem_wait(sem_t *sem)

+{

+   int rc;

+   while ((rc = sem_wait(sem)) && (rc = errno) == EINTR) ;

+   return rc;

+}

+

+#elif defined MDB_USE_SYSV_SEM

+

+typedef struct mdb_mutex {

+	int semid;

+	int semnum;

+	int *locked;

+} mdb_mutex_t[1], *mdb_mutexref_t;

+

+#define LOCK_MUTEX0(mutex)		mdb_sem_wait(mutex)

+#define UNLOCK_MUTEX(mutex)		do { \

+	struct sembuf sb = { 0, 1, SEM_UNDO }; \

+	sb.sem_num = (mutex)->semnum; \

+	*(mutex)->locked = 0; \

+	semop((mutex)->semid, &sb, 1); \

+} while(0)

+

+static int

+mdb_sem_wait(mdb_mutexref_t sem)

+{

+	int rc, *locked = sem->locked;

+	struct sembuf sb = { 0, -1, SEM_UNDO };

+	sb.sem_num = sem->semnum;

+	do {

+		if (!semop(sem->semid, &sb, 1)) {

+			rc = *locked ? MDB_OWNERDEAD : MDB_SUCCESS;

+			*locked = 1;

+			break;

+		}

+	} while ((rc = errno) == EINTR);

+	return rc;

+}

+

+#define mdb_mutex_consistent(mutex)	0

+

+#else	/* MDB_USE_POSIX_MUTEX: */

+	/** Shared mutex/semaphore as it is stored (mdb_mutex_t), and as

+	 *	local variables keep it (mdb_mutexref_t).

+	 *

+	 *	An mdb_mutex_t can be assigned to an mdb_mutexref_t.  They can

+	 *	be the same, or an array[size 1] and a pointer.

+	 *	@{

+	 */

+typedef pthread_mutex_t mdb_mutex_t[1], *mdb_mutexref_t;

+	/*	@} */

+	/** Lock the reader or writer mutex.

+	 *	Returns 0 or a code to give #mdb_mutex_failed(), as in #LOCK_MUTEX().

+	 */

+#define LOCK_MUTEX0(mutex)	pthread_mutex_lock(mutex)

+	/** Unlock the reader or writer mutex.

+	 */

+#define UNLOCK_MUTEX(mutex)	pthread_mutex_unlock(mutex)

+	/** Mark mutex-protected data as repaired, after death of previous owner.

+	 */

+#define mdb_mutex_consistent(mutex)	pthread_mutex_consistent(mutex)

+#endif	/* MDB_USE_POSIX_SEM || MDB_USE_SYSV_SEM */

+

+	/** Get the error code for the last failed system function.

+	 */

+#define	ErrCode()	errno

+

+	/** An abstraction for a file handle.

+	 *	On POSIX systems file handles are small integers. On Windows

+	 *	they're opaque pointers.

+	 */

+#define	HANDLE	int

+

+	/**	A value for an invalid file handle.

+	 *	Mainly used to initialize file variables and signify that they are

+	 *	unused.

+	 */

+#define INVALID_HANDLE_VALUE	(-1)

+

+	/** Get the size of a memory page for the system.

+	 *	This is the basic size that the platform's memory manager uses, and is

+	 *	fundamental to the use of memory-mapped files.

+	 */

+#define	GET_PAGESIZE(x)	((x) = sysconf(_SC_PAGE_SIZE))

+#endif

+

+#ifdef MDB_VL32

+#ifdef _WIN32

+#define	Y	"I64"

+#else

+#define	Y	"ll"

+#endif

+#else

+#define Y	Z

+#endif

+

+#if defined(_WIN32) || defined(MDB_USE_POSIX_SEM)

+#define MNAME_LEN	32

+#elif defined(MDB_USE_SYSV_SEM)

+#define MNAME_LEN	(sizeof(int))

+#else

+#define MNAME_LEN	(sizeof(pthread_mutex_t))

+#endif

+

+#ifdef MDB_USE_SYSV_SEM

+#define SYSV_SEM_FLAG	1		/**< SysV sems in lockfile format */

+#else

+#define SYSV_SEM_FLAG	0

+#endif

+

+/** @} */

+

+#ifdef MDB_ROBUST_SUPPORTED

+	/** Lock mutex, handle any error, set rc = result.

+	 *	Return 0 on success, nonzero (not rc) on error.

+	 */

+#define LOCK_MUTEX(rc, env, mutex) \

+	(((rc) = LOCK_MUTEX0(mutex)) && \

+	 ((rc) = mdb_mutex_failed(env, mutex, rc)))

+static int mdb_mutex_failed(MDB_env *env, mdb_mutexref_t mutex, int rc);

+#else

+#define LOCK_MUTEX(rc, env, mutex) ((rc) = LOCK_MUTEX0(mutex))

+#define mdb_mutex_failed(env, mutex, rc) (rc)

+#endif

+

+#ifndef _WIN32

+/**	A flag for opening a file and requesting synchronous data writes.

+ *	This is only used when writing a meta page. It's not strictly needed;

+ *	we could just do a normal write and then immediately perform a flush.

+ *	But if this flag is available it saves us an extra system call.

+ *

+ *	@note If O_DSYNC is undefined but exists in /usr/include,

+ * preferably set some compiler flag to get the definition.

+ */

+#ifndef MDB_DSYNC

+# ifdef O_DSYNC

+# define MDB_DSYNC	O_DSYNC

+# else

+# define MDB_DSYNC	O_SYNC

+# endif

+#endif

+#endif

+

+/** Function for flushing the data of a file. Define this to fsync

+ *	if fdatasync() is not supported.

+ */

+#ifndef MDB_FDATASYNC

+# define MDB_FDATASYNC	fdatasync

+#endif

+

+#ifndef MDB_MSYNC

+# define MDB_MSYNC(addr,len,flags)	msync(addr,len,flags)

+#endif

+

+#ifndef MS_SYNC

+#define	MS_SYNC	1

+#endif

+

+#ifndef MS_ASYNC

+#define	MS_ASYNC	0

+#endif

+

+	/** A page number in the database.

+	 *	Note that 64 bit page numbers are overkill, since pages themselves

+	 *	already represent 12-13 bits of addressable memory, and the OS will

+	 *	always limit applications to a maximum of 63 bits of address space.

+	 *

+	 *	@note In the #MDB_node structure, we only store 48 bits of this value,

+	 *	which thus limits us to only 60 bits of addressable data.

+	 */

+typedef MDB_ID	pgno_t;

+

+	/** A transaction ID.

+	 *	See struct MDB_txn.mt_txnid for details.

+	 */

+typedef MDB_ID	txnid_t;

+

+/** @defgroup debug	Debug Macros

+ *	@{

+ */

+#ifndef MDB_DEBUG

+	/**	Enable debug output.  Needs variable argument macros (a C99 feature).

+	 *	Set this to 1 for copious tracing. Set to 2 to add dumps of all IDLs

+	 *	read from and written to the database (used for free space management).

+	 */

+#define MDB_DEBUG 0

+#endif

+

+#if MDB_DEBUG

+static int mdb_debug;

+static txnid_t mdb_debug_start;

+

+	/**	Print a debug message with printf formatting.

+	 *	Requires double parenthesis around 2 or more args.

+	 */

+# define DPRINTF(args) ((void) ((mdb_debug) && DPRINTF0 args))

+# define DPRINTF0(fmt, ...) \

+	fprintf(stderr, "%s:%d " fmt "\n", mdb_func_, __LINE__, __VA_ARGS__)

+#else

+# define DPRINTF(args)	((void) 0)

+#endif

+	/**	Print a debug string.

+	 *	The string is printed literally, with no format processing.

+	 */

+#define DPUTS(arg)	DPRINTF(("%s", arg))

+	/** Debuging output value of a cursor DBI: Negative in a sub-cursor. */

+#define DDBI(mc) \

+	(((mc)->mc_flags & C_SUB) ? -(int)(mc)->mc_dbi : (int)(mc)->mc_dbi)

+/** @} */

+

+	/**	@brief The maximum size of a database page.

+	 *

+	 *	It is 32k or 64k, since value-PAGEBASE must fit in

+	 *	#MDB_page.%mp_upper.

+	 *

+	 *	LMDB will use database pages < OS pages if needed.

+	 *	That causes more I/O in write transactions: The OS must

+	 *	know (read) the whole page before writing a partial page.

+	 *

+	 *	Note that we don't currently support Huge pages. On Linux,

+	 *	regular data files cannot use Huge pages, and in general

+	 *	Huge pages aren't actually pageable. We rely on the OS

+	 *	demand-pager to read our data and page it out when memory

+	 *	pressure from other processes is high. So until OSs have

+	 *	actual paging support for Huge pages, they're not viable.

+	 */

+#define MAX_PAGESIZE	 (PAGEBASE ? 0x10000 : 0x8000)

+

+	/** The minimum number of keys required in a database page.

+	 *	Setting this to a larger value will place a smaller bound on the

+	 *	maximum size of a data item. Data items larger than this size will

+	 *	be pushed into overflow pages instead of being stored directly in

+	 *	the B-tree node. This value used to default to 4. With a page size

+	 *	of 4096 bytes that meant that any item larger than 1024 bytes would

+	 *	go into an overflow page. That also meant that on average 2-3KB of

+	 *	each overflow page was wasted space. The value cannot be lower than

+	 *	2 because then there would no longer be a tree structure. With this

+	 *	value, items larger than 2KB will go into overflow pages, and on

+	 *	average only 1KB will be wasted.

+	 */

+#define MDB_MINKEYS	 2

+

+	/**	A stamp that identifies a file as an LMDB file.

+	 *	There's nothing special about this value other than that it is easily

+	 *	recognizable, and it will reflect any byte order mismatches.

+	 */

+#define MDB_MAGIC	 0xBEEFC0DE

+

+	/**	The version number for a database's datafile format. */

+#define MDB_DATA_VERSION	 ((MDB_DEVEL) ? 999 : 1)

+	/**	The version number for a database's lockfile format. */

+#define MDB_LOCK_VERSION	 ((MDB_DEVEL) ? 999 : 1)

+

+	/**	@brief The max size of a key we can write, or 0 for computed max.

+	 *

+	 *	This macro should normally be left alone or set to 0.

+	 *	Note that a database with big keys or dupsort data cannot be

+	 *	reliably modified by a liblmdb which uses a smaller max.

+	 *	The default is 511 for backwards compat, or 0 when #MDB_DEVEL.

+	 *

+	 *	Other values are allowed, for backwards compat.  However:

+	 *	A value bigger than the computed max can break if you do not

+	 *	know what you are doing, and liblmdb <= 0.9.10 can break when

+	 *	modifying a DB with keys/dupsort data bigger than its max.

+	 *

+	 *	Data items in an #MDB_DUPSORT database are also limited to

+	 *	this size, since they're actually keys of a sub-DB.  Keys and

+	 *	#MDB_DUPSORT data items must fit on a node in a regular page.

+	 */

+#ifndef MDB_MAXKEYSIZE

+#define MDB_MAXKEYSIZE	 ((MDB_DEVEL) ? 0 : 511)

+#endif

+

+	/**	The maximum size of a key we can write to the environment. */

+#if MDB_MAXKEYSIZE

+#define ENV_MAXKEY(env)	(MDB_MAXKEYSIZE)

+#else

+#define ENV_MAXKEY(env)	((env)->me_maxkey)

+#endif

+

+	/**	@brief The maximum size of a data item.

+	 *

+	 *	We only store a 32 bit value for node sizes.

+	 */

+#define MAXDATASIZE	0xffffffffUL

+

+#if MDB_DEBUG

+	/**	Key size which fits in a #DKBUF.

+	 *	@ingroup debug

+	 */

+#define DKBUF_MAXKEYSIZE ((MDB_MAXKEYSIZE) > 0 ? (MDB_MAXKEYSIZE) : 511)

+	/**	A key buffer.

+	 *	@ingroup debug

+	 *	This is used for printing a hex dump of a key's contents.

+	 */

+#define DKBUF	char kbuf[DKBUF_MAXKEYSIZE*2+1]

+	/**	Display a key in hex.

+	 *	@ingroup debug

+	 *	Invoke a function to display a key in hex.

+	 */

+#define	DKEY(x)	mdb_dkey(x, kbuf)

+#else

+#define	DKBUF

+#define DKEY(x)	0

+#endif

+

+	/** An invalid page number.

+	 *	Mainly used to denote an empty tree.

+	 */

+#define P_INVALID	 (~(pgno_t)0)

+

+	/** Test if the flags \b f are set in a flag word \b w. */

+#define F_ISSET(w, f)	 (((w) & (f)) == (f))

+

+	/** Round \b n up to an even number. */

+#define EVEN(n)		(((n) + 1U) & -2) /* sign-extending -2 to match n+1U */

+

+	/**	Used for offsets within a single page.

+	 *	Since memory pages are typically 4 or 8KB in size, 12-13 bits,

+	 *	this is plenty.

+	 */

+typedef uint16_t	 indx_t;

+

+	/**	Default size of memory map.

+	 *	This is certainly too small for any actual applications. Apps should always set

+	 *	the size explicitly using #mdb_env_set_mapsize().

+	 */

+#define DEFAULT_MAPSIZE	1048576

+

+/**	@defgroup readers	Reader Lock Table

+ *	Readers don't acquire any locks for their data access. Instead, they

+ *	simply record their transaction ID in the reader table. The reader

+ *	mutex is needed just to find an empty slot in the reader table. The

+ *	slot's address is saved in thread-specific data so that subsequent read

+ *	transactions started by the same thread need no further locking to proceed.

+ *

+ *	If #MDB_NOTLS is set, the slot address is not saved in thread-specific data.

+ *

+ *	No reader table is used if the database is on a read-only filesystem, or

+ *	if #MDB_NOLOCK is set.

+ *

+ *	Since the database uses multi-version concurrency control, readers don't

+ *	actually need any locking. This table is used to keep track of which

+ *	readers are using data from which old transactions, so that we'll know

+ *	when a particular old transaction is no longer in use. Old transactions

+ *	that have discarded any data pages can then have those pages reclaimed

+ *	for use by a later write transaction.

+ *

+ *	The lock table is constructed such that reader slots are aligned with the

+ *	processor's cache line size. Any slot is only ever used by one thread.

+ *	This alignment guarantees that there will be no contention or cache

+ *	thrashing as threads update their own slot info, and also eliminates

+ *	any need for locking when accessing a slot.

+ *

+ *	A writer thread will scan every slot in the table to determine the oldest

+ *	outstanding reader transaction. Any freed pages older than this will be

+ *	reclaimed by the writer. The writer doesn't use any locks when scanning

+ *	this table. This means that there's no guarantee that the writer will

+ *	see the most up-to-date reader info, but that's not required for correct

+ *	operation - all we need is to know the upper bound on the oldest reader,

+ *	we don't care at all about the newest reader. So the only consequence of

+ *	reading stale information here is that old pages might hang around a

+ *	while longer before being reclaimed. That's actually good anyway, because

+ *	the longer we delay reclaiming old pages, the more likely it is that a

+ *	string of contiguous pages can be found after coalescing old pages from

+ *	many old transactions together.

+ *	@{

+ */

+	/**	Number of slots in the reader table.

+	 *	This value was chosen somewhat arbitrarily. 126 readers plus a

+	 *	couple mutexes fit exactly into 8KB on my development machine.

+	 *	Applications should set the table size using #mdb_env_set_maxreaders().

+	 */

+#define DEFAULT_READERS	126

+

+	/**	The size of a CPU cache line in bytes. We want our lock structures

+	 *	aligned to this size to avoid false cache line sharing in the

+	 *	lock table.

+	 *	This value works for most CPUs. For Itanium this should be 128.

+	 */

+#ifndef CACHELINE

+#define CACHELINE	64

+#endif

+

+	/**	The information we store in a single slot of the reader table.

+	 *	In addition to a transaction ID, we also record the process and

+	 *	thread ID that owns a slot, so that we can detect stale information,

+	 *	e.g. threads or processes that went away without cleaning up.

+	 *	@note We currently don't check for stale records. We simply re-init

+	 *	the table when we know that we're the only process opening the

+	 *	lock file.

+	 */

+typedef struct MDB_rxbody {

+	/**	Current Transaction ID when this transaction began, or (txnid_t)-1.

+	 *	Multiple readers that start at the same time will probably have the

+	 *	same ID here. Again, it's not important to exclude them from

+	 *	anything; all we need to know is which version of the DB they

+	 *	started from so we can avoid overwriting any data used in that

+	 *	particular version.

+	 */

+	volatile txnid_t		mrb_txnid;

+	/** The process ID of the process owning this reader txn. */

+	volatile MDB_PID_T	mrb_pid;

+	/** The thread ID of the thread owning this txn. */

+	volatile MDB_THR_T	mrb_tid;

+} MDB_rxbody;

+

+	/** The actual reader record, with cacheline padding. */

+typedef struct MDB_reader {

+	union {

+		MDB_rxbody mrx;

+		/** shorthand for mrb_txnid */

+#define	mr_txnid	mru.mrx.mrb_txnid

+#define	mr_pid	mru.mrx.mrb_pid

+#define	mr_tid	mru.mrx.mrb_tid

+		/** cache line alignment */

+		char pad[(sizeof(MDB_rxbody)+CACHELINE-1) & ~(CACHELINE-1)];

+	} mru;

+} MDB_reader;

+

+	/** The header for the reader table.

+	 *	The table resides in a memory-mapped file. (This is a different file

+	 *	than is used for the main database.)

+	 *

+	 *	For POSIX the actual mutexes reside in the shared memory of this

+	 *	mapped file. On Windows, mutexes are named objects allocated by the

+	 *	kernel; we store the mutex names in this mapped file so that other

+	 *	processes can grab them. This same approach is also used on

+	 *	MacOSX/Darwin (using named semaphores) since MacOSX doesn't support

+	 *	process-shared POSIX mutexes. For these cases where a named object

+	 *	is used, the object name is derived from a 64 bit FNV hash of the

+	 *	environment pathname. As such, naming collisions are extremely

+	 *	unlikely. If a collision occurs, the results are unpredictable.

+	 */

+typedef struct MDB_txbody {

+		/** Stamp identifying this as an LMDB file. It must be set

+		 *	to #MDB_MAGIC. */

+	uint32_t	mtb_magic;

+		/** Format of this lock file. Must be set to #MDB_LOCK_FORMAT. */

+	uint32_t	mtb_format;

+#if defined(_WIN32) || defined(MDB_USE_POSIX_SEM)

+	char	mtb_rmname[MNAME_LEN];

+#elif defined(MDB_USE_SYSV_SEM)

+	int 	mtb_semid;

+	int		mtb_rlocked;

+#else

+		/** Mutex protecting access to this table.

+		 *	This is the reader table lock used with LOCK_MUTEX().

+		 */

+	mdb_mutex_t	mtb_rmutex;

+#endif

+		/**	The ID of the last transaction committed to the database.

+		 *	This is recorded here only for convenience; the value can always

+		 *	be determined by reading the main database meta pages.

+		 */

+	volatile txnid_t		mtb_txnid;

+		/** The number of slots that have been used in the reader table.

+		 *	This always records the maximum count, it is not decremented

+		 *	when readers release their slots.

+		 */

+	volatile unsigned	mtb_numreaders;

+} MDB_txbody;

+

+	/** The actual reader table definition. */

+typedef struct MDB_txninfo {

+	union {

+		MDB_txbody mtb;

+#define mti_magic	mt1.mtb.mtb_magic

+#define mti_format	mt1.mtb.mtb_format

+#define mti_rmutex	mt1.mtb.mtb_rmutex

+#define mti_rmname	mt1.mtb.mtb_rmname

+#define mti_txnid	mt1.mtb.mtb_txnid

+#define mti_numreaders	mt1.mtb.mtb_numreaders

+#ifdef MDB_USE_SYSV_SEM

+#define	mti_semid	mt1.mtb.mtb_semid

+#define	mti_rlocked	mt1.mtb.mtb_rlocked

+#endif

+		char pad[(sizeof(MDB_txbody)+CACHELINE-1) & ~(CACHELINE-1)];

+	} mt1;

+	union {

+#if defined(_WIN32) || defined(MDB_USE_POSIX_SEM)

+		char mt2_wmname[MNAME_LEN];

+#define	mti_wmname	mt2.mt2_wmname

+#elif defined MDB_USE_SYSV_SEM

+		int mt2_wlocked;

+#define mti_wlocked	mt2.mt2_wlocked

+#else

+		mdb_mutex_t	mt2_wmutex;

+#define mti_wmutex	mt2.mt2_wmutex

+#endif

+		char pad[(MNAME_LEN+CACHELINE-1) & ~(CACHELINE-1)];

+	} mt2;

+	MDB_reader	mti_readers[1];

+} MDB_txninfo;

+

+	/** Lockfile format signature: version, features and field layout */

+#define MDB_LOCK_FORMAT \

+	((uint32_t) \

+	 ((MDB_LOCK_VERSION) \

+	  /* Flags which describe functionality */ \

+	  + (SYSV_SEM_FLAG << 18) \

+	  + (((MDB_PIDLOCK) != 0) << 16)))

+/** @} */

+

+/** Common header for all page types.

+ * Overflow records occupy a number of contiguous pages with no

+ * headers on any page after the first.

+ */

+typedef struct MDB_page {

+#define	mp_pgno	mp_p.p_pgno

+#define	mp_next	mp_p.p_next

+	union {

+		pgno_t		p_pgno;	/**< page number */

+		struct MDB_page *p_next; /**< for in-memory list of freed pages */

+	} mp_p;

+	uint16_t	mp_pad;

+/**	@defgroup mdb_page	Page Flags

+ *	@ingroup internal

+ *	Flags for the page headers.

+ *	@{

+ */

+#define	P_BRANCH	 0x01		/**< branch page */

+#define	P_LEAF		 0x02		/**< leaf page */

+#define	P_OVERFLOW	 0x04		/**< overflow page */

+#define	P_META		 0x08		/**< meta page */

+#define	P_DIRTY		 0x10		/**< dirty page, also set for #P_SUBP pages */

+#define	P_LEAF2		 0x20		/**< for #MDB_DUPFIXED records */

+#define	P_SUBP		 0x40		/**< for #MDB_DUPSORT sub-pages */

+#define	P_LOOSE		 0x4000		/**< page was dirtied then freed, can be reused */

+#define	P_KEEP		 0x8000		/**< leave this page alone during spill */

+/** @} */

+	uint16_t	mp_flags;		/**< @ref mdb_page */

+#define mp_lower	mp_pb.pb.pb_lower

+#define mp_upper	mp_pb.pb.pb_upper

+#define mp_pages	mp_pb.pb_pages

+	union {

+		struct {

+			indx_t		pb_lower;		/**< lower bound of free space */

+			indx_t		pb_upper;		/**< upper bound of free space */

+		} pb;

+		uint32_t	pb_pages;	/**< number of overflow pages */

+	} mp_pb;

+	indx_t		mp_ptrs[1];		/**< dynamic size */

+} MDB_page;

+

+	/** Size of the page header, excluding dynamic data at the end */

+#define PAGEHDRSZ	 ((unsigned) offsetof(MDB_page, mp_ptrs))

+

+	/** Address of first usable data byte in a page, after the header */

+#define METADATA(p)	 ((void *)((char *)(p) + PAGEHDRSZ))

+

+	/** ITS#7713, change PAGEBASE to handle 65536 byte pages */

+#define	PAGEBASE	((MDB_DEVEL) ? PAGEHDRSZ : 0)

+

+	/** Number of nodes on a page */

+#define NUMKEYS(p)	 (((p)->mp_lower - (PAGEHDRSZ-PAGEBASE)) >> 1)

+

+	/** The amount of space remaining in the page */

+#define SIZELEFT(p)	 (indx_t)((p)->mp_upper - (p)->mp_lower)

+

+	/** The percentage of space used in the page, in tenths of a percent. */

+#define PAGEFILL(env, p) (1000L * ((env)->me_psize - PAGEHDRSZ - SIZELEFT(p)) / \

+				((env)->me_psize - PAGEHDRSZ))

+	/** The minimum page fill factor, in tenths of a percent.

+	 *	Pages emptier than this are candidates for merging.

+	 */

+#define FILL_THRESHOLD	 250

+

+	/** Test if a page is a leaf page */

+#define IS_LEAF(p)	 F_ISSET((p)->mp_flags, P_LEAF)

+	/** Test if a page is a LEAF2 page */

+#define IS_LEAF2(p)	 F_ISSET((p)->mp_flags, P_LEAF2)

+	/** Test if a page is a branch page */

+#define IS_BRANCH(p)	 F_ISSET((p)->mp_flags, P_BRANCH)

+	/** Test if a page is an overflow page */

+#define IS_OVERFLOW(p)	 F_ISSET((p)->mp_flags, P_OVERFLOW)

+	/** Test if a page is a sub page */

+#define IS_SUBP(p)	 F_ISSET((p)->mp_flags, P_SUBP)

+

+	/** The number of overflow pages needed to store the given size. */

+#define OVPAGES(size, psize)	((PAGEHDRSZ-1 + (size)) / (psize) + 1)

+

+	/** Link in #MDB_txn.%mt_loose_pgs list */

+#define NEXT_LOOSE_PAGE(p)		(*(MDB_page **)((p) + 2))

+

+	/** Header for a single key/data pair within a page.

+	 * Used in pages of type #P_BRANCH and #P_LEAF without #P_LEAF2.

+	 * We guarantee 2-byte alignment for 'MDB_node's.

+	 */

+typedef struct MDB_node {

+	/** lo and hi are used for data size on leaf nodes and for

+	 * child pgno on branch nodes. On 64 bit platforms, flags

+	 * is also used for pgno. (Branch nodes have no flags).

+	 * They are in host byte order in case that lets some

+	 * accesses be optimized into a 32-bit word access.

+	 */

+#if BYTE_ORDER == LITTLE_ENDIAN

+	unsigned short	mn_lo, mn_hi;	/**< part of data size or pgno */

+#else

+	unsigned short	mn_hi, mn_lo;

+#endif

+/** @defgroup mdb_node Node Flags

+ *	@ingroup internal

+ *	Flags for node headers.

+ *	@{

+ */

+#define F_BIGDATA	 0x01			/**< data put on overflow page */

+#define F_SUBDATA	 0x02			/**< data is a sub-database */

+#define F_DUPDATA	 0x04			/**< data has duplicates */

+

+/** valid flags for #mdb_node_add() */

+#define	NODE_ADD_FLAGS	(F_DUPDATA|F_SUBDATA|MDB_RESERVE|MDB_APPEND)

+

+/** @} */

+	unsigned short	mn_flags;		/**< @ref mdb_node */

+	unsigned short	mn_ksize;		/**< key size */

+	char		mn_data[1];			/**< key and data are appended here */

+} MDB_node;

+

+	/** Size of the node header, excluding dynamic data at the end */

+#define NODESIZE	 offsetof(MDB_node, mn_data)

+

+	/** Bit position of top word in page number, for shifting mn_flags */

+#define PGNO_TOPWORD ((pgno_t)-1 > 0xffffffffu ? 32 : 0)

+

+	/** Size of a node in a branch page with a given key.

+	 *	This is just the node header plus the key, there is no data.

+	 */

+#define INDXSIZE(k)	 (NODESIZE + ((k) == NULL ? 0 : (k)->mv_size))

+

+	/** Size of a node in a leaf page with a given key and data.

+	 *	This is node header plus key plus data size.

+	 */

+#define LEAFSIZE(k, d)	 (NODESIZE + (k)->mv_size + (d)->mv_size)

+

+	/** Address of node \b i in page \b p */

+#define NODEPTR(p, i)	 ((MDB_node *)((char *)(p) + (p)->mp_ptrs[i] + PAGEBASE))

+

+	/** Address of the key for the node */

+#define NODEKEY(node)	 (void *)((node)->mn_data)

+

+	/** Address of the data for a node */

+#define NODEDATA(node)	 (void *)((char *)(node)->mn_data + (node)->mn_ksize)

+

+	/** Get the page number pointed to by a branch node */

+#define NODEPGNO(node) \

+	((node)->mn_lo | ((pgno_t) (node)->mn_hi << 16) | \

+	 (PGNO_TOPWORD ? ((pgno_t) (node)->mn_flags << PGNO_TOPWORD) : 0))

+	/** Set the page number in a branch node */

+#define SETPGNO(node,pgno)	do { \

+	(node)->mn_lo = (pgno) & 0xffff; (node)->mn_hi = (pgno) >> 16; \

+	if (PGNO_TOPWORD) (node)->mn_flags = (pgno) >> PGNO_TOPWORD; } while(0)

+

+	/** Get the size of the data in a leaf node */

+#define NODEDSZ(node)	 ((node)->mn_lo | ((unsigned)(node)->mn_hi << 16))

+	/** Set the size of the data for a leaf node */

+#define SETDSZ(node,size)	do { \

+	(node)->mn_lo = (size) & 0xffff; (node)->mn_hi = (size) >> 16;} while(0)

+	/** The size of a key in a node */

+#define NODEKSZ(node)	 ((node)->mn_ksize)

+

+	/** Copy a page number from src to dst */

+#ifdef MISALIGNED_OK

+#define COPY_PGNO(dst,src)	dst = src

+#else

+#if SIZE_MAX > 4294967295UL

+#define COPY_PGNO(dst,src)	do { \

+	unsigned short *s, *d;	\

+	s = (unsigned short *)&(src);	\

+	d = (unsigned short *)&(dst);	\

+	*d++ = *s++;	\

+	*d++ = *s++;	\

+	*d++ = *s++;	\

+	*d = *s;	\

+} while (0)

+#else

+#define COPY_PGNO(dst,src)	do { \

+	unsigned short *s, *d;	\

+	s = (unsigned short *)&(src);	\

+	d = (unsigned short *)&(dst);	\

+	*d++ = *s++;	\

+	*d = *s;	\

+} while (0)

+#endif

+#endif

+	/** The address of a key in a LEAF2 page.

+	 *	LEAF2 pages are used for #MDB_DUPFIXED sorted-duplicate sub-DBs.

+	 *	There are no node headers, keys are stored contiguously.

+	 */

+#define LEAF2KEY(p, i, ks)	((char *)(p) + PAGEHDRSZ + ((i)*(ks)))

+

+	/** Set the \b node's key into \b keyptr, if requested. */

+#define MDB_GET_KEY(node, keyptr)	{ if ((keyptr) != NULL) { \

+	(keyptr)->mv_size = NODEKSZ(node); (keyptr)->mv_data = NODEKEY(node); } }

+

+	/** Set the \b node's key into \b key. */

+#define MDB_GET_KEY2(node, key)	{ key.mv_size = NODEKSZ(node); key.mv_data = NODEKEY(node); }

+

+	/** Information about a single database in the environment. */

+typedef struct MDB_db {

+	uint32_t	md_pad;		/**< also ksize for LEAF2 pages */

+	uint16_t	md_flags;	/**< @ref mdb_dbi_open */

+	uint16_t	md_depth;	/**< depth of this tree */

+	pgno_t		md_branch_pages;	/**< number of internal pages */

+	pgno_t		md_leaf_pages;		/**< number of leaf pages */

+	pgno_t		md_overflow_pages;	/**< number of overflow pages */

+	mdb_size_t	md_entries;		/**< number of data items */

+	pgno_t		md_root;		/**< the root page of this tree */

+} MDB_db;

+

+	/** mdb_dbi_open flags */

+#define MDB_VALID	0x8000		/**< DB handle is valid, for me_dbflags */

+#define PERSISTENT_FLAGS	(0xffff & ~(MDB_VALID))

+#define VALID_FLAGS	(MDB_REVERSEKEY|MDB_DUPSORT|MDB_INTEGERKEY|MDB_DUPFIXED|\

+	MDB_INTEGERDUP|MDB_REVERSEDUP|MDB_CREATE)

+

+	/** Handle for the DB used to track free pages. */

+#define	FREE_DBI	0

+	/** Handle for the default DB. */

+#define	MAIN_DBI	1

+	/** Number of DBs in metapage (free and main) - also hardcoded elsewhere */

+#define CORE_DBS	2

+

+	/** Number of meta pages - also hardcoded elsewhere */

+#define NUM_METAS	2

+

+	/** Meta page content.

+	 *	A meta page is the start point for accessing a database snapshot.

+	 *	Pages 0-1 are meta pages. Transaction N writes meta page #(N % 2).

+	 */

+typedef struct MDB_meta {

+		/** Stamp identifying this as an LMDB file. It must be set

+		 *	to #MDB_MAGIC. */

+	uint32_t	mm_magic;

+		/** Version number of this file. Must be set to #MDB_DATA_VERSION. */

+	uint32_t	mm_version;

+#ifdef MDB_VL32

+	union {		/* always zero since we don't support fixed mapping in MDB_VL32 */

+		MDB_ID	mmun_ull;

+		void *mmun_address;

+	} mm_un;

+#define	mm_address mm_un.mmun_address

+#else

+	void		*mm_address;		/**< address for fixed mapping */

+#endif

+	pgno_t		mm_mapsize;			/**< size of mmap region */

+	MDB_db		mm_dbs[CORE_DBS];	/**< first is free space, 2nd is main db */

+	/** The size of pages used in this DB */

+#define	mm_psize	mm_dbs[FREE_DBI].md_pad

+	/** Any persistent environment flags. @ref mdb_env */

+#define	mm_flags	mm_dbs[FREE_DBI].md_flags

+	pgno_t		mm_last_pg;			/**< last used page in file */

+	volatile txnid_t	mm_txnid;	/**< txnid that committed this page */

+} MDB_meta;

+

+	/** Buffer for a stack-allocated meta page.

+	 *	The members define size and alignment, and silence type

+	 *	aliasing warnings.  They are not used directly; that could

+	 *	mean incorrectly using several union members in parallel.

+	 */

+typedef union MDB_metabuf {

+	MDB_page	mb_page;

+	struct {

+		char		mm_pad[PAGEHDRSZ];

+		MDB_meta	mm_meta;

+	} mb_metabuf;

+} MDB_metabuf;

+

+	/** Auxiliary DB info.

+	 *	The information here is mostly static/read-only. There is

+	 *	only a single copy of this record in the environment.

+	 */

+typedef struct MDB_dbx {

+	MDB_val		md_name;		/**< name of the database */

+	MDB_cmp_func	*md_cmp;	/**< function for comparing keys */

+	MDB_cmp_func	*md_dcmp;	/**< function for comparing data items */

+	MDB_rel_func	*md_rel;	/**< user relocate function */

+	void		*md_relctx;		/**< user-provided context for md_rel */

+} MDB_dbx;

+

+	/** A database transaction.

+	 *	Every operation requires a transaction handle.

+	 */

+struct MDB_txn {

+	MDB_txn		*mt_parent;		/**< parent of a nested txn */

+	/** Nested txn under this txn, set together with flag #MDB_TXN_HAS_CHILD */

+	MDB_txn		*mt_child;

+	pgno_t		mt_next_pgno;	/**< next unallocated page */

+#ifdef MDB_VL32

+	pgno_t		mt_last_pgno;	/**< last written page */

+#endif

+	/** The ID of this transaction. IDs are integers incrementing from 1.

+	 *	Only committed write transactions increment the ID. If a transaction

+	 *	aborts, the ID may be re-used by the next writer.

+	 */

+	txnid_t		mt_txnid;

+	MDB_env		*mt_env;		/**< the DB environment */

+	/** The list of pages that became unused during this transaction.

+	 */

+	MDB_IDL		mt_free_pgs;

+	/** The list of loose pages that became unused and may be reused

+	 *	in this transaction, linked through #NEXT_LOOSE_PAGE(page).

+	 */

+	MDB_page	*mt_loose_pgs;

+	/* #Number of loose pages (#mt_loose_pgs) */

+	int			mt_loose_count;

+	/** The sorted list of dirty pages we temporarily wrote to disk

+	 *	because the dirty list was full. page numbers in here are

+	 *	shifted left by 1, deleted slots have the LSB set.

+	 */

+	MDB_IDL		mt_spill_pgs;

+	union {

+		/** For write txns: Modified pages. Sorted when not MDB_WRITEMAP. */

+		MDB_ID2L	dirty_list;

+		/** For read txns: This thread/txn's reader table slot, or NULL. */

+		MDB_reader	*reader;

+	} mt_u;

+	/** Array of records for each DB known in the environment. */

+	MDB_dbx		*mt_dbxs;

+	/** Array of MDB_db records for each known DB */

+	MDB_db		*mt_dbs;

+	/** Array of sequence numbers for each DB handle */

+	unsigned int	*mt_dbiseqs;

+/** @defgroup mt_dbflag	Transaction DB Flags

+ *	@ingroup internal

+ * @{

+ */

+#define DB_DIRTY	0x01		/**< DB was modified or is DUPSORT data */

+#define DB_STALE	0x02		/**< Named-DB record is older than txnID */

+#define DB_NEW		0x04		/**< Named-DB handle opened in this txn */

+#define DB_VALID	0x08		/**< DB handle is valid, see also #MDB_VALID */

+#define DB_USRVALID	0x10		/**< As #DB_VALID, but not set for #FREE_DBI */

+/** @} */

+	/** In write txns, array of cursors for each DB */

+	MDB_cursor	**mt_cursors;

+	/** Array of flags for each DB */

+	unsigned char	*mt_dbflags;

+#ifdef MDB_VL32

+	/** List of read-only pages (actually chunks) */

+	MDB_ID3L	mt_rpages;

+	/** We map chunks of 16 pages. Even though Windows uses 4KB pages, all

+	 * mappings must begin on 64KB boundaries. So we round off all pgnos to

+	 * a chunk boundary. We do the same on Linux for symmetry, and also to

+	 * reduce the frequency of mmap/munmap calls.

+	 */

+#define MDB_RPAGE_CHUNK	16

+#define MDB_TRPAGE_SIZE	4096	/**< size of #mt_rpages array of chunks */

+#define MDB_TRPAGE_MAX	(MDB_TRPAGE_SIZE-1)	/**< maximum chunk index */

+	unsigned int mt_rpcheck;	/**< threshold for reclaiming unref'd chunks */

+#endif

+	/**	Number of DB records in use, or 0 when the txn is finished.

+	 *	This number only ever increments until the txn finishes; we

+	 *	don't decrement it when individual DB handles are closed.

+	 */

+	MDB_dbi		mt_numdbs;

+

+/** @defgroup mdb_txn	Transaction Flags

+ *	@ingroup internal

+ *	@{

+ */

+	/** #mdb_txn_begin() flags */

+#define MDB_TXN_BEGIN_FLAGS	(MDB_NOMETASYNC|MDB_NOSYNC|MDB_RDONLY)

+#define MDB_TXN_NOMETASYNC	MDB_NOMETASYNC	/**< don't sync meta for this txn on commit */

+#define MDB_TXN_NOSYNC		MDB_NOSYNC	/**< don't sync this txn on commit */

+#define MDB_TXN_RDONLY		MDB_RDONLY	/**< read-only transaction */

+	/* internal txn flags */

+#define MDB_TXN_WRITEMAP	MDB_WRITEMAP	/**< copy of #MDB_env flag in writers */

+#define MDB_TXN_FINISHED	0x01		/**< txn is finished or never began */

+#define MDB_TXN_ERROR		0x02		/**< txn is unusable after an error */

+#define MDB_TXN_DIRTY		0x04		/**< must write, even if dirty list is empty */

+#define MDB_TXN_SPILLS		0x08		/**< txn or a parent has spilled pages */

+#define MDB_TXN_HAS_CHILD	0x10		/**< txn has an #MDB_txn.%mt_child */

+	/** most operations on the txn are currently illegal */

+#define MDB_TXN_BLOCKED		(MDB_TXN_FINISHED|MDB_TXN_ERROR|MDB_TXN_HAS_CHILD)

+/** @} */

+	unsigned int	mt_flags;		/**< @ref mdb_txn */

+	/** #dirty_list room: Array size - \#dirty pages visible to this txn.

+	 *	Includes ancestor txns' dirty pages not hidden by other txns'

+	 *	dirty/spilled pages. Thus commit(nested txn) has room to merge

+	 *	dirty_list into mt_parent after freeing hidden mt_parent pages.

+	 */

+	unsigned int	mt_dirty_room;

+};

+

+/** Enough space for 2^32 nodes with minimum of 2 keys per node. I.e., plenty.

+ * At 4 keys per node, enough for 2^64 nodes, so there's probably no need to

+ * raise this on a 64 bit machine.

+ */

+#define CURSOR_STACK		 32

+

+struct MDB_xcursor;

+

+	/** Cursors are used for all DB operations.

+	 *	A cursor holds a path of (page pointer, key index) from the DB

+	 *	root to a position in the DB, plus other state. #MDB_DUPSORT

+	 *	cursors include an xcursor to the current data item. Write txns

+	 *	track their cursors and keep them up to date when data moves.

+	 *	Exception: An xcursor's pointer to a #P_SUBP page can be stale.

+	 *	(A node with #F_DUPDATA but no #F_SUBDATA contains a subpage).

+	 */

+struct MDB_cursor {

+	/** Next cursor on this DB in this txn */

+	MDB_cursor	*mc_next;

+	/** Backup of the original cursor if this cursor is a shadow */

+	MDB_cursor	*mc_backup;

+	/** Context used for databases with #MDB_DUPSORT, otherwise NULL */

+	struct MDB_xcursor	*mc_xcursor;

+	/** The transaction that owns this cursor */

+	MDB_txn		*mc_txn;

+	/** The database handle this cursor operates on */

+	MDB_dbi		mc_dbi;

+	/** The database record for this cursor */

+	MDB_db		*mc_db;

+	/** The database auxiliary record for this cursor */

+	MDB_dbx		*mc_dbx;

+	/** The @ref mt_dbflag for this database */

+	unsigned char	*mc_dbflag;

+	unsigned short 	mc_snum;	/**< number of pushed pages */

+	unsigned short	mc_top;		/**< index of top page, normally mc_snum-1 */

+/** @defgroup mdb_cursor	Cursor Flags

+ *	@ingroup internal

+ *	Cursor state flags.

+ *	@{

+ */

+#define C_INITIALIZED	0x01	/**< cursor has been initialized and is valid */

+#define C_EOF	0x02			/**< No more data */

+#define C_SUB	0x04			/**< Cursor is a sub-cursor */

+#define C_DEL	0x08			/**< last op was a cursor_del */

+#define C_UNTRACK	0x40		/**< Un-track cursor when closing */

+#define C_WRITEMAP	MDB_TXN_WRITEMAP /**< Copy of txn flag */

+/** Read-only cursor into the txn's original snapshot in the map.

+ *	Set for read-only txns, and in #mdb_page_alloc() for #FREE_DBI when

+ *	#MDB_DEVEL & 2. Only implements code which is necessary for this.

+ */

+#define C_ORIG_RDONLY	MDB_TXN_RDONLY

+/** @} */

+	unsigned int	mc_flags;	/**< @ref mdb_cursor */

+	MDB_page	*mc_pg[CURSOR_STACK];	/**< stack of pushed pages */

+	indx_t		mc_ki[CURSOR_STACK];	/**< stack of page indices */

+#ifdef MDB_VL32

+	MDB_page	*mc_ovpg;		/**< a referenced overflow page */

+#endif

+};

+

+	/** Context for sorted-dup records.

+	 *	We could have gone to a fully recursive design, with arbitrarily

+	 *	deep nesting of sub-databases. But for now we only handle these

+	 *	levels - main DB, optional sub-DB, sorted-duplicate DB.

+	 */

+typedef struct MDB_xcursor {

+	/** A sub-cursor for traversing the Dup DB */

+	MDB_cursor mx_cursor;

+	/** The database record for this Dup DB */

+	MDB_db	mx_db;

+	/**	The auxiliary DB record for this Dup DB */

+	MDB_dbx	mx_dbx;

+	/** The @ref mt_dbflag for this Dup DB */

+	unsigned char mx_dbflag;

+} MDB_xcursor;

+

+	/** State of FreeDB old pages, stored in the MDB_env */

+typedef struct MDB_pgstate {

+	pgno_t		*mf_pghead;	/**< Reclaimed freeDB pages, or NULL before use */

+	txnid_t		mf_pglast;	/**< ID of last used record, or 0 if !mf_pghead */

+} MDB_pgstate;

+

+	/** The database environment. */

+struct MDB_env {

+	HANDLE		me_fd;		/**< The main data file */

+	HANDLE		me_lfd;		/**< The lock file */

+	HANDLE		me_mfd;			/**< just for writing the meta pages */

+#if defined(MDB_VL32) && defined(_WIN32)

+	HANDLE		me_fmh;		/**< File Mapping handle */

+#endif

+	/** Failed to update the meta page. Probably an I/O error. */

+#define	MDB_FATAL_ERROR	0x80000000U

+	/** Some fields are initialized. */

+#define	MDB_ENV_ACTIVE	0x20000000U

+	/** me_txkey is set */

+#define	MDB_ENV_TXKEY	0x10000000U

+	/** fdatasync is unreliable */

+#define	MDB_FSYNCONLY	0x08000000U

+	uint32_t 	me_flags;		/**< @ref mdb_env */

+	unsigned int	me_psize;	/**< DB page size, inited from me_os_psize */

+	unsigned int	me_os_psize;	/**< OS page size, from #GET_PAGESIZE */

+	unsigned int	me_maxreaders;	/**< size of the reader table */

+	/** Max #MDB_txninfo.%mti_numreaders of interest to #mdb_env_close() */

+	volatile int	me_close_readers;

+	MDB_dbi		me_numdbs;		/**< number of DBs opened */

+	MDB_dbi		me_maxdbs;		/**< size of the DB table */

+	MDB_PID_T	me_pid;		/**< process ID of this env */

+	char		*me_path;		/**< path to the DB files */

+	char		*me_map;		/**< the memory map of the data file */

+	MDB_txninfo	*me_txns;		/**< the memory map of the lock file or NULL */

+	MDB_meta	*me_metas[NUM_METAS];	/**< pointers to the two meta pages */

+	void		*me_pbuf;		/**< scratch area for DUPSORT put() */

+	MDB_txn		*me_txn;		/**< current write transaction */

+	MDB_txn		*me_txn0;		/**< prealloc'd write transaction */

+	mdb_size_t	me_mapsize;		/**< size of the data memory map */

+	off_t		me_size;		/**< current file size */

+	pgno_t		me_maxpg;		/**< me_mapsize / me_psize */

+	MDB_dbx		*me_dbxs;		/**< array of static DB info */

+	uint16_t	*me_dbflags;	/**< array of flags from MDB_db.md_flags */

+	unsigned int	*me_dbiseqs;	/**< array of dbi sequence numbers */

+	pthread_key_t	me_txkey;	/**< thread-key for readers */

+	txnid_t		me_pgoldest;	/**< ID of oldest reader last time we looked */

+	MDB_pgstate	me_pgstate;		/**< state of old pages from freeDB */

+#	define		me_pglast	me_pgstate.mf_pglast

+#	define		me_pghead	me_pgstate.mf_pghead

+	MDB_page	*me_dpages;		/**< list of malloc'd blocks for re-use */

+	/** IDL of pages that became unused in a write txn */

+	MDB_IDL		me_free_pgs;

+	/** ID2L of pages written during a write txn. Length MDB_IDL_UM_SIZE. */

+	MDB_ID2L	me_dirty_list;

+	/** Max number of freelist items that can fit in a single overflow page */

+	int			me_maxfree_1pg;

+	/** Max size of a node on a page */

+	unsigned int	me_nodemax;

+#if !(MDB_MAXKEYSIZE)

+	unsigned int	me_maxkey;	/**< max size of a key */

+#endif

+	int		me_live_reader;		/**< have liveness lock in reader table */

+#ifdef _WIN32

+	int		me_pidquery;		/**< Used in OpenProcess */

+#endif

+#ifdef MDB_USE_POSIX_MUTEX	/* Posix mutexes reside in shared mem */

+#	define		me_rmutex	me_txns->mti_rmutex /**< Shared reader lock */

+#	define		me_wmutex	me_txns->mti_wmutex /**< Shared writer lock */

+#else

+	mdb_mutex_t	me_rmutex;

+	mdb_mutex_t	me_wmutex;

+#endif

+#ifdef MDB_VL32

+	MDB_ID3L	me_rpages;	/**< like #mt_rpages, but global to env */

+	pthread_mutex_t	me_rpmutex;	/**< control access to #me_rpages */

+#define MDB_ERPAGE_SIZE	16384

+#define MDB_ERPAGE_MAX	(MDB_ERPAGE_SIZE-1)

+	unsigned int me_rpcheck;

+#endif

+	void		*me_userctx;	 /**< User-settable context */

+	MDB_assert_func *me_assert_func; /**< Callback for assertion failures */

+};

+

+	/** Nested transaction */

+typedef struct MDB_ntxn {

+	MDB_txn		mnt_txn;		/**< the transaction */

+	MDB_pgstate	mnt_pgstate;	/**< parent transaction's saved freestate */

+} MDB_ntxn;

+

+	/** max number of pages to commit in one writev() call */

+#define MDB_COMMIT_PAGES	 64

+#if defined(IOV_MAX) && IOV_MAX < MDB_COMMIT_PAGES

+#undef MDB_COMMIT_PAGES

+#define MDB_COMMIT_PAGES	IOV_MAX

+#endif

+

+	/** max bytes to write in one call */

+#define MAX_WRITE		(0x40000000U >> (sizeof(ssize_t) == 4))

+

+	/** Check \b txn and \b dbi arguments to a function */

+#define TXN_DBI_EXIST(txn, dbi, validity) \

+	((txn) && (dbi)<(txn)->mt_numdbs && ((txn)->mt_dbflags[dbi] & (validity)))

+

+	/** Check for misused \b dbi handles */

+#define TXN_DBI_CHANGED(txn, dbi) \

+	((txn)->mt_dbiseqs[dbi] != (txn)->mt_env->me_dbiseqs[dbi])

+

+static int  mdb_page_alloc(MDB_cursor *mc, int num, MDB_page **mp);

+static int  mdb_page_new(MDB_cursor *mc, uint32_t flags, int num, MDB_page **mp);

+static int  mdb_page_touch(MDB_cursor *mc);

+

+#define MDB_END_NAMES {"committed", "empty-commit", "abort", "reset", \

+	"reset-tmp", "fail-begin", "fail-beginchild"}

+enum {

+	/* mdb_txn_end operation number, for logging */

+	MDB_END_COMMITTED, MDB_END_EMPTY_COMMIT, MDB_END_ABORT, MDB_END_RESET,

+	MDB_END_RESET_TMP, MDB_END_FAIL_BEGIN, MDB_END_FAIL_BEGINCHILD

+};

+#define MDB_END_OPMASK	0x0F	/**< mask for #mdb_txn_end() operation number */

+#define MDB_END_UPDATE	0x10	/**< update env state (DBIs) */

+#define MDB_END_FREE	0x20	/**< free txn unless it is #MDB_env.%me_txn0 */

+#define MDB_END_SLOT MDB_NOTLS	/**< release any reader slot if #MDB_NOTLS */

+static void mdb_txn_end(MDB_txn *txn, unsigned mode);

+

+static int  mdb_page_get(MDB_cursor *mc, pgno_t pgno, MDB_page **mp, int *lvl);

+static int  mdb_page_search_root(MDB_cursor *mc,

+			    MDB_val *key, int modify);

+#define MDB_PS_MODIFY	1

+#define MDB_PS_ROOTONLY	2

+#define MDB_PS_FIRST	4

+#define MDB_PS_LAST		8

+static int  mdb_page_search(MDB_cursor *mc,

+			    MDB_val *key, int flags);

+static int	mdb_page_merge(MDB_cursor *csrc, MDB_cursor *cdst);

+

+#define MDB_SPLIT_REPLACE	MDB_APPENDDUP	/**< newkey is not new */

+static int	mdb_page_split(MDB_cursor *mc, MDB_val *newkey, MDB_val *newdata,

+				pgno_t newpgno, unsigned int nflags);

+

+static int  mdb_env_read_header(MDB_env *env, MDB_meta *meta);

+static MDB_meta *mdb_env_pick_meta(const MDB_env *env);

+static int  mdb_env_write_meta(MDB_txn *txn);

+#ifdef MDB_USE_POSIX_MUTEX /* Drop unused excl arg */

+# define mdb_env_close0(env, excl) mdb_env_close1(env)

+#endif

+static void mdb_env_close0(MDB_env *env, int excl);

+

+static MDB_node *mdb_node_search(MDB_cursor *mc, MDB_val *key, int *exactp);

+static int  mdb_node_add(MDB_cursor *mc, indx_t indx,

+			    MDB_val *key, MDB_val *data, pgno_t pgno, unsigned int flags);

+static void mdb_node_del(MDB_cursor *mc, int ksize);

+static void mdb_node_shrink(MDB_page *mp, indx_t indx);

+static int	mdb_node_move(MDB_cursor *csrc, MDB_cursor *cdst, int fromleft);

+static int  mdb_node_read(MDB_cursor *mc, MDB_node *leaf, MDB_val *data);

+static size_t	mdb_leaf_size(MDB_env *env, MDB_val *key, MDB_val *data);

+static size_t	mdb_branch_size(MDB_env *env, MDB_val *key);

+

+static int	mdb_rebalance(MDB_cursor *mc);

+static int	mdb_update_key(MDB_cursor *mc, MDB_val *key);

+

+static void	mdb_cursor_pop(MDB_cursor *mc);

+static int	mdb_cursor_push(MDB_cursor *mc, MDB_page *mp);

+

+static int	mdb_cursor_del0(MDB_cursor *mc);

+static int	mdb_del0(MDB_txn *txn, MDB_dbi dbi, MDB_val *key, MDB_val *data, unsigned flags);

+static int	mdb_cursor_sibling(MDB_cursor *mc, int move_right);

+static int	mdb_cursor_next(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op);

+static int	mdb_cursor_prev(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op);

+static int	mdb_cursor_set(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op,

+				int *exactp);

+static int	mdb_cursor_first(MDB_cursor *mc, MDB_val *key, MDB_val *data);

+static int	mdb_cursor_last(MDB_cursor *mc, MDB_val *key, MDB_val *data);

+

+static void	mdb_cursor_init(MDB_cursor *mc, MDB_txn *txn, MDB_dbi dbi, MDB_xcursor *mx);

+static void	mdb_xcursor_init0(MDB_cursor *mc);

+static void	mdb_xcursor_init1(MDB_cursor *mc, MDB_node *node);

+static void	mdb_xcursor_init2(MDB_cursor *mc, MDB_xcursor *src_mx, int force);

+

+static int	mdb_drop0(MDB_cursor *mc, int subs);

+static void mdb_default_cmp(MDB_txn *txn, MDB_dbi dbi);

+static int mdb_reader_check0(MDB_env *env, int rlocked, int *dead);

+

+/** @cond */

+static MDB_cmp_func	mdb_cmp_memn, mdb_cmp_memnr, mdb_cmp_int, mdb_cmp_cint, mdb_cmp_long;

+/** @endcond */

+

+/** Compare two items pointing at size_t's of unknown alignment. */

+#ifdef MISALIGNED_OK

+# define mdb_cmp_clong mdb_cmp_long

+#else

+# define mdb_cmp_clong mdb_cmp_cint

+#endif

+

+#ifdef _WIN32

+static SECURITY_DESCRIPTOR mdb_null_sd;

+static SECURITY_ATTRIBUTES mdb_all_sa;

+static int mdb_sec_inited;

+

+static int utf8_to_utf16(const char *src, int srcsize, wchar_t **dst, int *dstsize);

+#endif

+

+/** Return the library version info. */

+char * ESECT

+mdb_version(int *major, int *minor, int *patch)

+{

+	if (major) *major = MDB_VERSION_MAJOR;

+	if (minor) *minor = MDB_VERSION_MINOR;

+	if (patch) *patch = MDB_VERSION_PATCH;

+	return MDB_VERSION_STRING;

+}

+

+/** Table of descriptions for LMDB @ref errors */

+static char *const mdb_errstr[] = {

+	"MDB_KEYEXIST: Key/data pair already exists",

+	"MDB_NOTFOUND: No matching key/data pair found",

+	"MDB_PAGE_NOTFOUND: Requested page not found",

+	"MDB_CORRUPTED: Located page was wrong type",

+	"MDB_PANIC: Update of meta page failed or environment had fatal error",

+	"MDB_VERSION_MISMATCH: Database environment version mismatch",

+	"MDB_INVALID: File is not an LMDB file",

+	"MDB_MAP_FULL: Environment mapsize limit reached",

+	"MDB_DBS_FULL: Environment maxdbs limit reached",

+	"MDB_READERS_FULL: Environment maxreaders limit reached",

+	"MDB_TLS_FULL: Thread-local storage keys full - too many environments open",

+	"MDB_TXN_FULL: Transaction has too many dirty pages - transaction too big",

+	"MDB_CURSOR_FULL: Internal error - cursor stack limit reached",

+	"MDB_PAGE_FULL: Internal error - page has no more space",

+	"MDB_MAP_RESIZED: Database contents grew beyond environment mapsize",

+	"MDB_INCOMPATIBLE: Operation and DB incompatible, or DB flags changed",

+	"MDB_BAD_RSLOT: Invalid reuse of reader locktable slot",

+	"MDB_BAD_TXN: Transaction must abort, has a child, or is invalid",

+	"MDB_BAD_VALSIZE: Unsupported size of key/DB name/data, or wrong DUPFIXED size",

+	"MDB_BAD_DBI: The specified DBI handle was closed/changed unexpectedly",

+};

+

+char *

+mdb_strerror(int err)

+{

+#ifdef _WIN32

+	/** HACK: pad 4KB on stack over the buf. Return system msgs in buf.

+	 *	This works as long as no function between the call to mdb_strerror

+	 *	and the actual use of the message uses more than 4K of stack.

+	 */

+#define MSGSIZE	1024

+#define PADSIZE	4096

+	char buf[MSGSIZE+PADSIZE], *ptr = buf;

+#endif

+	int i;

+	if (!err)

+		return ("Successful return: 0");

+

+	if (err >= MDB_KEYEXIST && err <= MDB_LAST_ERRCODE) {

+		i = err - MDB_KEYEXIST;

+		return mdb_errstr[i];

+	}

+

+#ifdef _WIN32

+	/* These are the C-runtime error codes we use. The comment indicates

+	 * their numeric value, and the Win32 error they would correspond to

+	 * if the error actually came from a Win32 API. A major mess, we should

+	 * have used LMDB-specific error codes for everything.

+	 */

+	switch(err) {

+	case ENOENT:	/* 2, FILE_NOT_FOUND */

+	case EIO:		/* 5, ACCESS_DENIED */

+	case ENOMEM:	/* 12, INVALID_ACCESS */

+	case EACCES:	/* 13, INVALID_DATA */

+	case EBUSY:		/* 16, CURRENT_DIRECTORY */

+	case EINVAL:	/* 22, BAD_COMMAND */

+	case ENOSPC:	/* 28, OUT_OF_PAPER */

+		return strerror(err);

+	default:

+		;

+	}

+	buf[0] = 0;

+	FormatMessageA(FORMAT_MESSAGE_FROM_SYSTEM |

+		FORMAT_MESSAGE_IGNORE_INSERTS,

+		NULL, err, 0, ptr, MSGSIZE, (va_list *)buf+MSGSIZE);

+	return ptr;

+#else

+	return strerror(err);

+#endif

+}

+

+/** assert(3) variant in cursor context */

+#define mdb_cassert(mc, expr)	mdb_assert0((mc)->mc_txn->mt_env, expr, #expr)

+/** assert(3) variant in transaction context */

+#define mdb_tassert(txn, expr)	mdb_assert0((txn)->mt_env, expr, #expr)

+/** assert(3) variant in environment context */

+#define mdb_eassert(env, expr)	mdb_assert0(env, expr, #expr)

+

+#ifndef NDEBUG

+# define mdb_assert0(env, expr, expr_txt) ((expr) ? (void)0 : \

+		mdb_assert_fail(env, expr_txt, mdb_func_, __FILE__, __LINE__))

+

+static void ESECT

+mdb_assert_fail(MDB_env *env, const char *expr_txt,

+	const char *func, const char *file, int line)

+{

+	char buf[400];

+	sprintf(buf, "%.100s:%d: Assertion '%.200s' failed in %.40s()",

+		file, line, expr_txt, func);

+	if (env->me_assert_func)

+		env->me_assert_func(env, buf);

+	fprintf(stderr, "%s\n", buf);

+	abort();

+}

+#else

+# define mdb_assert0(env, expr, expr_txt) ((void) 0)

+#endif /* NDEBUG */

+

+#if MDB_DEBUG

+/** Return the page number of \b mp which may be sub-page, for debug output */

+static pgno_t

+mdb_dbg_pgno(MDB_page *mp)

+{

+	pgno_t ret;

+	COPY_PGNO(ret, mp->mp_pgno);

+	return ret;

+}

+

+/** Display a key in hexadecimal and return the address of the result.

+ * @param[in] key the key to display

+ * @param[in] buf the buffer to write into. Should always be #DKBUF.

+ * @return The key in hexadecimal form.

+ */

+char *

+mdb_dkey(MDB_val *key, char *buf)

+{

+	char *ptr = buf;

+	unsigned char *c = key->mv_data;

+	unsigned int i;

+

+	if (!key)

+		return "";

+

+	if (key->mv_size > DKBUF_MAXKEYSIZE)

+		return "MDB_MAXKEYSIZE";

+	/* may want to make this a dynamic check: if the key is mostly

+	 * printable characters, print it as-is instead of converting to hex.

+	 */

+#if 1

+	buf[0] = '\0';

+	for (i=0; i<key->mv_size; i++)

+		ptr += sprintf(ptr, "%02x", *c++);

+#else

+	sprintf(buf, "%.*s", key->mv_size, key->mv_data);

+#endif

+	return buf;

+}

+

+static const char *

+mdb_leafnode_type(MDB_node *n)

+{

+	static char *const tp[2][2] = {{"", ": DB"}, {": sub-page", ": sub-DB"}};

+	return F_ISSET(n->mn_flags, F_BIGDATA) ? ": overflow page" :

+		tp[F_ISSET(n->mn_flags, F_DUPDATA)][F_ISSET(n->mn_flags, F_SUBDATA)];

+}

+

+/** Display all the keys in the page. */

+void

+mdb_page_list(MDB_page *mp)

+{

+	pgno_t pgno = mdb_dbg_pgno(mp);

+	const char *type, *state = (mp->mp_flags & P_DIRTY) ? ", dirty" : "";

+	MDB_node *node;

+	unsigned int i, nkeys, nsize, total = 0;

+	MDB_val key;

+	DKBUF;

+

+	switch (mp->mp_flags & (P_BRANCH|P_LEAF|P_LEAF2|P_META|P_OVERFLOW|P_SUBP)) {

+	case P_BRANCH:              type = "Branch page";		break;

+	case P_LEAF:                type = "Leaf page";			break;

+	case P_LEAF|P_SUBP:         type = "Sub-page";			break;

+	case P_LEAF|P_LEAF2:        type = "LEAF2 page";		break;

+	case P_LEAF|P_LEAF2|P_SUBP: type = "LEAF2 sub-page";	break;

+	case P_OVERFLOW:

+		fprintf(stderr, "Overflow page %"Y"u pages %u%s\n",

+			pgno, mp->mp_pages, state);

+		return;

+	case P_META:

+		fprintf(stderr, "Meta-page %"Y"u txnid %"Y"u\n",

+			pgno, ((MDB_meta *)METADATA(mp))->mm_txnid);

+		return;

+	default:

+		fprintf(stderr, "Bad page %"Y"u flags 0x%u\n", pgno, mp->mp_flags);

+		return;

+	}

+

+	nkeys = NUMKEYS(mp);

+	fprintf(stderr, "%s %"Y"u numkeys %d%s\n", type, pgno, nkeys, state);

+

+	for (i=0; i<nkeys; i++) {

+		if (IS_LEAF2(mp)) {	/* LEAF2 pages have no mp_ptrs[] or node headers */

+			key.mv_size = nsize = mp->mp_pad;

+			key.mv_data = LEAF2KEY(mp, i, nsize);

+			total += nsize;

+			fprintf(stderr, "key %d: nsize %d, %s\n", i, nsize, DKEY(&key));

+			continue;

+		}

+		node = NODEPTR(mp, i);

+		key.mv_size = node->mn_ksize;

+		key.mv_data = node->mn_data;

+		nsize = NODESIZE + key.mv_size;

+		if (IS_BRANCH(mp)) {

+			fprintf(stderr, "key %d: page %"Y"u, %s\n", i, NODEPGNO(node),

+				DKEY(&key));

+			total += nsize;

+		} else {

+			if (F_ISSET(node->mn_flags, F_BIGDATA))

+				nsize += sizeof(pgno_t);

+			else

+				nsize += NODEDSZ(node);

+			total += nsize;

+			nsize += sizeof(indx_t);

+			fprintf(stderr, "key %d: nsize %d, %s%s\n",

+				i, nsize, DKEY(&key), mdb_leafnode_type(node));

+		}

+		total = EVEN(total);

+	}

+	fprintf(stderr, "Total: header %d + contents %d + unused %d\n",

+		IS_LEAF2(mp) ? PAGEHDRSZ : PAGEBASE + mp->mp_lower, total, SIZELEFT(mp));

+}

+

+void

+mdb_cursor_chk(MDB_cursor *mc)

+{

+	unsigned int i;

+	MDB_node *node;

+	MDB_page *mp;

+

+	if (!mc->mc_snum || !(mc->mc_flags & C_INITIALIZED)) return;

+	for (i=0; i<mc->mc_top; i++) {

+		mp = mc->mc_pg[i];

+		node = NODEPTR(mp, mc->mc_ki[i]);

+		if (NODEPGNO(node) != mc->mc_pg[i+1]->mp_pgno)

+			printf("oops!\n");

+	}

+	if (mc->mc_ki[i] >= NUMKEYS(mc->mc_pg[i]))

+		printf("ack!\n");

+	if (mc->mc_xcursor && (mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED)) {

+		node = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);

+		if (((node->mn_flags & (F_DUPDATA|F_SUBDATA)) == F_DUPDATA) &&

+			mc->mc_xcursor->mx_cursor.mc_pg[0] != NODEDATA(node)) {

+			printf("blah!\n");

+		}

+	}

+}

+#endif

+

+#if (MDB_DEBUG) > 2

+/** Count all the pages in each DB and in the freelist

+ *  and make sure it matches the actual number of pages

+ *  being used.

+ *  All named DBs must be open for a correct count.

+ */

+static void mdb_audit(MDB_txn *txn)

+{

+	MDB_cursor mc;

+	MDB_val key, data;

+	MDB_ID freecount, count;

+	MDB_dbi i;

+	int rc;

+

+	freecount = 0;

+	mdb_cursor_init(&mc, txn, FREE_DBI, NULL);

+	while ((rc = mdb_cursor_get(&mc, &key, &data, MDB_NEXT)) == 0)

+		freecount += *(MDB_ID *)data.mv_data;

+	mdb_tassert(txn, rc == MDB_NOTFOUND);

+

+	count = 0;

+	for (i = 0; i<txn->mt_numdbs; i++) {

+		MDB_xcursor mx;

+		if (!(txn->mt_dbflags[i] & DB_VALID))

+			continue;

+		mdb_cursor_init(&mc, txn, i, &mx);

+		if (txn->mt_dbs[i].md_root == P_INVALID)

+			continue;

+		count += txn->mt_dbs[i].md_branch_pages +

+			txn->mt_dbs[i].md_leaf_pages +

+			txn->mt_dbs[i].md_overflow_pages;

+		if (txn->mt_dbs[i].md_flags & MDB_DUPSORT) {

+			rc = mdb_page_search(&mc, NULL, MDB_PS_FIRST);

+			for (; rc == MDB_SUCCESS; rc = mdb_cursor_sibling(&mc, 1)) {

+				unsigned j;

+				MDB_page *mp;

+				mp = mc.mc_pg[mc.mc_top];

+				for (j=0; j<NUMKEYS(mp); j++) {

+					MDB_node *leaf = NODEPTR(mp, j);

+					if (leaf->mn_flags & F_SUBDATA) {

+						MDB_db db;

+						memcpy(&db, NODEDATA(leaf), sizeof(db));

+						count += db.md_branch_pages + db.md_leaf_pages +

+							db.md_overflow_pages;

+					}

+				}

+			}

+			mdb_tassert(txn, rc == MDB_NOTFOUND);

+		}

+	}

+	if (freecount + count + NUM_METAS != txn->mt_next_pgno) {

+		fprintf(stderr, "audit: %"Y"u freecount: %"Y"u count: %"Y"u total: %"Y"u next_pgno: %"Y"u\n",

+			txn->mt_txnid, freecount, count+NUM_METAS,

+			freecount+count+NUM_METAS, txn->mt_next_pgno);

+	}

+}

+#endif

+

+int

+mdb_cmp(MDB_txn *txn, MDB_dbi dbi, const MDB_val *a, const MDB_val *b)

+{

+	return txn->mt_dbxs[dbi].md_cmp(a, b);

+}

+

+int

+mdb_dcmp(MDB_txn *txn, MDB_dbi dbi, const MDB_val *a, const MDB_val *b)

+{

+	MDB_cmp_func *dcmp = txn->mt_dbxs[dbi].md_dcmp;

+#if UINT_MAX < SIZE_MAX || defined(MDB_VL32)

+	if (dcmp == mdb_cmp_int && a->mv_size == sizeof(mdb_size_t))

+		dcmp = mdb_cmp_clong;

+#endif

+	return dcmp(a, b);

+}

+

+/** Allocate memory for a page.

+ * Re-use old malloc'd pages first for singletons, otherwise just malloc.

+ */

+static MDB_page *

+mdb_page_malloc(MDB_txn *txn, unsigned num)

+{

+	MDB_env *env = txn->mt_env;

+	MDB_page *ret = env->me_dpages;

+	size_t psize = env->me_psize, sz = psize, off;

+	/* For ! #MDB_NOMEMINIT, psize counts how much to init.

+	 * For a single page alloc, we init everything after the page header.

+	 * For multi-page, we init the final page; if the caller needed that

+	 * many pages they will be filling in at least up to the last page.

+	 */

+	if (num == 1) {

+		if (ret) {

+			VGMEMP_ALLOC(env, ret, sz);

+			VGMEMP_DEFINED(ret, sizeof(ret->mp_next));

+			env->me_dpages = ret->mp_next;

+			return ret;

+		}

+		psize -= off = PAGEHDRSZ;

+	} else {

+		sz *= num;

+		off = sz - psize;

+	}

+	if ((ret = malloc(sz)) != NULL) {

+		VGMEMP_ALLOC(env, ret, sz);

+		if (!(env->me_flags & MDB_NOMEMINIT)) {

+			memset((char *)ret + off, 0, psize);

+			ret->mp_pad = 0;

+		}

+	} else {

+		txn->mt_flags |= MDB_TXN_ERROR;

+	}

+	return ret;

+}

+/** Free a single page.

+ * Saves single pages to a list, for future reuse.

+ * (This is not used for multi-page overflow pages.)

+ */

+static void

+mdb_page_free(MDB_env *env, MDB_page *mp)

+{

+	mp->mp_next = env->me_dpages;

+	VGMEMP_FREE(env, mp);

+	env->me_dpages = mp;

+}

+

+/** Free a dirty page */

+static void

+mdb_dpage_free(MDB_env *env, MDB_page *dp)

+{

+	if (!IS_OVERFLOW(dp) || dp->mp_pages == 1) {

+		mdb_page_free(env, dp);

+	} else {

+		/* large pages just get freed directly */

+		VGMEMP_FREE(env, dp);

+		free(dp);

+	}

+}

+

+/**	Return all dirty pages to dpage list */

+static void

+mdb_dlist_free(MDB_txn *txn)

+{

+	MDB_env *env = txn->mt_env;

+	MDB_ID2L dl = txn->mt_u.dirty_list;

+	unsigned i, n = dl[0].mid;

+

+	for (i = 1; i <= n; i++) {

+		mdb_dpage_free(env, dl[i].mptr);

+	}

+	dl[0].mid = 0;

+}

+

+#ifdef MDB_VL32

+static void

+mdb_page_unref(MDB_txn *txn, MDB_page *mp)

+{

+	pgno_t pgno;

+	MDB_ID3L tl = txn->mt_rpages;

+	unsigned x, rem;

+	if (mp->mp_flags & (P_SUBP|P_DIRTY))

+		return;

+	rem = mp->mp_pgno & (MDB_RPAGE_CHUNK-1);

+	pgno = mp->mp_pgno ^ rem;

+	x = mdb_mid3l_search(tl, pgno);

+	if (x != tl[0].mid && tl[x+1].mid == mp->mp_pgno)

+		x++;

+	if (tl[x].mref)

+		tl[x].mref--;

+}

+#define MDB_PAGE_UNREF(txn, mp)	mdb_page_unref(txn, mp)

+

+static void

+mdb_cursor_unref(MDB_cursor *mc)

+{

+	int i;

+	if (!mc->mc_snum || !mc->mc_pg[0] || IS_SUBP(mc->mc_pg[0]))

+		return;

+	for (i=0; i<mc->mc_snum; i++)

+		mdb_page_unref(mc->mc_txn, mc->mc_pg[i]);

+	if (mc->mc_ovpg) {

+		mdb_page_unref(mc->mc_txn, mc->mc_ovpg);

+		mc->mc_ovpg = 0;

+	}

+	mc->mc_snum = mc->mc_top = 0;

+	mc->mc_pg[0] = NULL;

+	mc->mc_flags &= ~C_INITIALIZED;

+}

+#else

+#define MDB_PAGE_UNREF(txn, mp)

+#endif /* MDB_VL32 */

+

+/** Loosen or free a single page.

+ * Saves single pages to a list for future reuse

+ * in this same txn. It has been pulled from the freeDB

+ * and already resides on the dirty list, but has been

+ * deleted. Use these pages first before pulling again

+ * from the freeDB.

+ *

+ * If the page wasn't dirtied in this txn, just add it

+ * to this txn's free list.

+ */

+static int

+mdb_page_loose(MDB_cursor *mc, MDB_page *mp)

+{

+	int loose = 0;

+	pgno_t pgno = mp->mp_pgno;

+	MDB_txn *txn = mc->mc_txn;

+

+	if ((mp->mp_flags & P_DIRTY) && mc->mc_dbi != FREE_DBI) {

+		if (txn->mt_parent) {

+			MDB_ID2 *dl = txn->mt_u.dirty_list;

+			/* If txn has a parent, make sure the page is in our

+			 * dirty list.

+			 */

+			if (dl[0].mid) {

+				unsigned x = mdb_mid2l_search(dl, pgno);

+				if (x <= dl[0].mid && dl[x].mid == pgno) {

+					if (mp != dl[x].mptr) { /* bad cursor? */

+						mc->mc_flags &= ~(C_INITIALIZED|C_EOF);

+						txn->mt_flags |= MDB_TXN_ERROR;

+						return MDB_CORRUPTED;

+					}

+					/* ok, it's ours */

+					loose = 1;

+				}

+			}

+		} else {

+			/* no parent txn, so it's just ours */

+			loose = 1;

+		}

+	}

+	if (loose) {

+		DPRINTF(("loosen db %d page %"Y"u", DDBI(mc),

+			mp->mp_pgno));

+		NEXT_LOOSE_PAGE(mp) = txn->mt_loose_pgs;

+		txn->mt_loose_pgs = mp;

+		txn->mt_loose_count++;

+		mp->mp_flags |= P_LOOSE;

+	} else {

+		int rc = mdb_midl_append(&txn->mt_free_pgs, pgno);

+		if (rc)

+			return rc;

+	}

+

+	return MDB_SUCCESS;

+}

+

+/** Set or clear P_KEEP in dirty, non-overflow, non-sub pages watched by txn.

+ * @param[in] mc A cursor handle for the current operation.

+ * @param[in] pflags Flags of the pages to update:

+ * P_DIRTY to set P_KEEP, P_DIRTY|P_KEEP to clear it.

+ * @param[in] all No shortcuts. Needed except after a full #mdb_page_flush().

+ * @return 0 on success, non-zero on failure.

+ */

+static int

+mdb_pages_xkeep(MDB_cursor *mc, unsigned pflags, int all)

+{

+	enum { Mask = P_SUBP|P_DIRTY|P_LOOSE|P_KEEP };

+	MDB_txn *txn = mc->mc_txn;

+	MDB_cursor *m3, *m0 = mc;

+	MDB_xcursor *mx;

+	MDB_page *dp, *mp;

+	MDB_node *leaf;

+	unsigned i, j;

+	int rc = MDB_SUCCESS, level;

+

+	/* Mark pages seen by cursors */

+	if (mc->mc_flags & C_UNTRACK)

+		mc = NULL;				/* will find mc in mt_cursors */

+	for (i = txn->mt_numdbs;; mc = txn->mt_cursors[--i]) {

+		for (; mc; mc=mc->mc_next) {

+			if (!(mc->mc_flags & C_INITIALIZED))

+				continue;

+			for (m3 = mc;; m3 = &mx->mx_cursor) {

+				mp = NULL;

+				for (j=0; j<m3->mc_snum; j++) {

+					mp = m3->mc_pg[j];

+					if ((mp->mp_flags & Mask) == pflags)

+						mp->mp_flags ^= P_KEEP;

+				}

+				mx = m3->mc_xcursor;

+				/* Proceed to mx if it is at a sub-database */

+				if (! (mx && (mx->mx_cursor.mc_flags & C_INITIALIZED)))

+					break;

+				if (! (mp && (mp->mp_flags & P_LEAF)))

+					break;

+				leaf = NODEPTR(mp, m3->mc_ki[j-1]);

+				if (!(leaf->mn_flags & F_SUBDATA))

+					break;

+			}

+		}

+		if (i == 0)

+			break;

+	}

+

+	if (all) {

+		/* Mark dirty root pages */

+		for (i=0; i<txn->mt_numdbs; i++) {

+			if (txn->mt_dbflags[i] & DB_DIRTY) {

+				pgno_t pgno = txn->mt_dbs[i].md_root;

+				if (pgno == P_INVALID)

+					continue;

+				if ((rc = mdb_page_get(m0, pgno, &dp, &level)) != MDB_SUCCESS)

+					break;

+				if ((dp->mp_flags & Mask) == pflags && level <= 1)

+					dp->mp_flags ^= P_KEEP;

+			}

+		}

+	}

+

+	return rc;

+}

+

+static int mdb_page_flush(MDB_txn *txn, int keep);

+

+/**	Spill pages from the dirty list back to disk.

+ * This is intended to prevent running into #MDB_TXN_FULL situations,

+ * but note that they may still occur in a few cases:

+ *	1) our estimate of the txn size could be too small. Currently this

+ *	 seems unlikely, except with a large number of #MDB_MULTIPLE items.

+ *	2) child txns may run out of space if their parents dirtied a

+ *	 lot of pages and never spilled them. TODO: we probably should do

+ *	 a preemptive spill during #mdb_txn_begin() of a child txn, if

+ *	 the parent's dirty_room is below a given threshold.

+ *

+ * Otherwise, if not using nested txns, it is expected that apps will

+ * not run into #MDB_TXN_FULL any more. The pages are flushed to disk

+ * the same way as for a txn commit, e.g. their P_DIRTY flag is cleared.

+ * If the txn never references them again, they can be left alone.

+ * If the txn only reads them, they can be used without any fuss.

+ * If the txn writes them again, they can be dirtied immediately without

+ * going thru all of the work of #mdb_page_touch(). Such references are

+ * handled by #mdb_page_unspill().

+ *

+ * Also note, we never spill DB root pages, nor pages of active cursors,

+ * because we'll need these back again soon anyway. And in nested txns,

+ * we can't spill a page in a child txn if it was already spilled in a

+ * parent txn. That would alter the parent txns' data even though

+ * the child hasn't committed yet, and we'd have no way to undo it if

+ * the child aborted.

+ *

+ * @param[in] m0 cursor A cursor handle identifying the transaction and

+ *	database for which we are checking space.

+ * @param[in] key For a put operation, the key being stored.

+ * @param[in] data For a put operation, the data being stored.

+ * @return 0 on success, non-zero on failure.

+ */

+static int

+mdb_page_spill(MDB_cursor *m0, MDB_val *key, MDB_val *data)

+{

+	MDB_txn *txn = m0->mc_txn;

+	MDB_page *dp;

+	MDB_ID2L dl = txn->mt_u.dirty_list;

+	unsigned int i, j, need;

+	int rc;

+

+	if (m0->mc_flags & C_SUB)

+		return MDB_SUCCESS;

+

+	/* Estimate how much space this op will take */

+	i = m0->mc_db->md_depth;

+	/* Named DBs also dirty the main DB */

+	if (m0->mc_dbi >= CORE_DBS)

+		i += txn->mt_dbs[MAIN_DBI].md_depth;

+	/* For puts, roughly factor in the key+data size */

+	if (key)

+		i += (LEAFSIZE(key, data) + txn->mt_env->me_psize) / txn->mt_env->me_psize;

+	i += i;	/* double it for good measure */

+	need = i;

+

+	if (txn->mt_dirty_room > i)

+		return MDB_SUCCESS;

+

+	if (!txn->mt_spill_pgs) {

+		txn->mt_spill_pgs = mdb_midl_alloc(MDB_IDL_UM_MAX);

+		if (!txn->mt_spill_pgs)

+			return ENOMEM;

+	} else {

+		/* purge deleted slots */

+		MDB_IDL sl = txn->mt_spill_pgs;

+		unsigned int num = sl[0];

+		j=0;

+		for (i=1; i<=num; i++) {

+			if (!(sl[i] & 1))

+				sl[++j] = sl[i];

+		}

+		sl[0] = j;

+	}

+

+	/* Preserve pages which may soon be dirtied again */

+	if ((rc = mdb_pages_xkeep(m0, P_DIRTY, 1)) != MDB_SUCCESS)

+		goto done;

+

+	/* Less aggressive spill - we originally spilled the entire dirty list,

+	 * with a few exceptions for cursor pages and DB root pages. But this

+	 * turns out to be a lot of wasted effort because in a large txn many

+	 * of those pages will need to be used again. So now we spill only 1/8th

+	 * of the dirty pages. Testing revealed this to be a good tradeoff,

+	 * better than 1/2, 1/4, or 1/10.

+	 */

+	if (need < MDB_IDL_UM_MAX / 8)

+		need = MDB_IDL_UM_MAX / 8;

+

+	/* Save the page IDs of all the pages we're flushing */

+	/* flush from the tail forward, this saves a lot of shifting later on. */

+	for (i=dl[0].mid; i && need; i--) {

+		MDB_ID pn = dl[i].mid << 1;

+		dp = dl[i].mptr;

+		if (dp->mp_flags & (P_LOOSE|P_KEEP))

+			continue;

+		/* Can't spill twice, make sure it's not already in a parent's

+		 * spill list.

+		 */

+		if (txn->mt_parent) {

+			MDB_txn *tx2;

+			for (tx2 = txn->mt_parent; tx2; tx2 = tx2->mt_parent) {

+				if (tx2->mt_spill_pgs) {

+					j = mdb_midl_search(tx2->mt_spill_pgs, pn);

+					if (j <= tx2->mt_spill_pgs[0] && tx2->mt_spill_pgs[j] == pn) {

+						dp->mp_flags |= P_KEEP;

+						break;

+					}

+				}

+			}

+			if (tx2)

+				continue;

+		}

+		if ((rc = mdb_midl_append(&txn->mt_spill_pgs, pn)))

+			goto done;

+		need--;

+	}

+	mdb_midl_sort(txn->mt_spill_pgs);

+

+	/* Flush the spilled part of dirty list */

+	if ((rc = mdb_page_flush(txn, i)) != MDB_SUCCESS)

+		goto done;

+

+	/* Reset any dirty pages we kept that page_flush didn't see */

+	rc = mdb_pages_xkeep(m0, P_DIRTY|P_KEEP, i);

+

+done:

+	txn->mt_flags |= rc ? MDB_TXN_ERROR : MDB_TXN_SPILLS;

+	return rc;

+}

+

+/** Find oldest txnid still referenced. Expects txn->mt_txnid > 0. */

+static txnid_t

+mdb_find_oldest(MDB_txn *txn)

+{

+	int i;

+	txnid_t mr, oldest = txn->mt_txnid - 1;

+	if (txn->mt_env->me_txns) {

+		MDB_reader *r = txn->mt_env->me_txns->mti_readers;

+		for (i = txn->mt_env->me_txns->mti_numreaders; --i >= 0; ) {

+			if (r[i].mr_pid) {

+				mr = r[i].mr_txnid;

+				if (oldest > mr)

+					oldest = mr;

+			}

+		}

+	}

+	return oldest;

+}

+

+/** Add a page to the txn's dirty list */

+static void

+mdb_page_dirty(MDB_txn *txn, MDB_page *mp)

+{

+	MDB_ID2 mid;

+	int rc, (*insert)(MDB_ID2L, MDB_ID2 *);

+

+	if (txn->mt_flags & MDB_TXN_WRITEMAP) {

+		insert = mdb_mid2l_append;

+	} else {

+		insert = mdb_mid2l_insert;

+	}

+	mid.mid = mp->mp_pgno;

+	mid.mptr = mp;

+	rc = insert(txn->mt_u.dirty_list, &mid);

+	mdb_tassert(txn, rc == 0);

+	txn->mt_dirty_room--;

+}

+

+/** Allocate page numbers and memory for writing.  Maintain me_pglast,

+ * me_pghead and mt_next_pgno.

+ *

+ * If there are free pages available from older transactions, they

+ * are re-used first. Otherwise allocate a new page at mt_next_pgno.

+ * Do not modify the freedB, just merge freeDB records into me_pghead[]

+ * and move me_pglast to say which records were consumed.  Only this

+ * function can create me_pghead and move me_pglast/mt_next_pgno.

+ * When #MDB_DEVEL & 2, it is not affected by #mdb_freelist_save(): it

+ * then uses the transaction's original snapshot of the freeDB.

+ * @param[in] mc cursor A cursor handle identifying the transaction and

+ *	database for which we are allocating.

+ * @param[in] num the number of pages to allocate.

+ * @param[out] mp Address of the allocated page(s). Requests for multiple pages

+ *  will always be satisfied by a single contiguous chunk of memory.

+ * @return 0 on success, non-zero on failure.

+ */

+static int

+mdb_page_alloc(MDB_cursor *mc, int num, MDB_page **mp)

+{

+#ifdef MDB_PARANOID	/* Seems like we can ignore this now */

+	/* Get at most <Max_retries> more freeDB records once me_pghead

+	 * has enough pages.  If not enough, use new pages from the map.

+	 * If <Paranoid> and mc is updating the freeDB, only get new

+	 * records if me_pghead is empty. Then the freelist cannot play

+	 * catch-up with itself by growing while trying to save it.

+	 */

+	enum { Paranoid = 1, Max_retries = 500 };

+#else

+	enum { Paranoid = 0, Max_retries = INT_MAX /*infinite*/ };

+#endif

+	int rc, retry = num * 60;

+	MDB_txn *txn = mc->mc_txn;

+	MDB_env *env = txn->mt_env;

+	pgno_t pgno, *mop = env->me_pghead;

+	unsigned i, j, mop_len = mop ? mop[0] : 0, n2 = num-1;

+	MDB_page *np;

+	txnid_t oldest = 0, last;

+	MDB_cursor_op op;

+	MDB_cursor m2;

+	int found_old = 0;

+

+	/* If there are any loose pages, just use them */

+	if (num == 1 && txn->mt_loose_pgs) {

+		np = txn->mt_loose_pgs;

+		txn->mt_loose_pgs = NEXT_LOOSE_PAGE(np);

+		txn->mt_loose_count--;

+		DPRINTF(("db %d use loose page %"Y"u", DDBI(mc),

+				np->mp_pgno));

+		*mp = np;

+		return MDB_SUCCESS;

+	}

+

+	*mp = NULL;

+

+	/* If our dirty list is already full, we can't do anything */

+	if (txn->mt_dirty_room == 0) {

+		rc = MDB_TXN_FULL;

+		goto fail;

+	}

+

+	for (op = MDB_FIRST;; op = MDB_NEXT) {

+		MDB_val key, data;

+		MDB_node *leaf;

+		pgno_t *idl;

+

+		/* Seek a big enough contiguous page range. Prefer

+		 * pages at the tail, just truncating the list.

+		 */

+		if (mop_len > n2) {

+			i = mop_len;

+			do {

+				pgno = mop[i];

+				if (mop[i-n2] == pgno+n2)

+					goto search_done;

+			} while (--i > n2);

+			if (--retry < 0)

+				break;

+		}

+

+		if (op == MDB_FIRST) {	/* 1st iteration */

+			/* Prepare to fetch more and coalesce */

+			last = env->me_pglast;

+			oldest = env->me_pgoldest;

+			mdb_cursor_init(&m2, txn, FREE_DBI, NULL);

+#if (MDB_DEVEL) & 2	/* "& 2" so MDB_DEVEL=1 won't hide bugs breaking freeDB */

+			/* Use original snapshot. TODO: Should need less care in code

+			 * which modifies the database. Maybe we can delete some code?

+			 */

+			m2.mc_flags |= C_ORIG_RDONLY;

+			m2.mc_db = &env->me_metas[(txn->mt_txnid-1) & 1]->mm_dbs[FREE_DBI];

+			m2.mc_dbflag = (unsigned char *)""; /* probably unnecessary */

+#endif

+			if (last) {

+				op = MDB_SET_RANGE;

+				key.mv_data = &last; /* will look up last+1 */

+				key.mv_size = sizeof(last);

+			}

+			if (Paranoid && mc->mc_dbi == FREE_DBI)

+				retry = -1;

+		}

+		if (Paranoid && retry < 0 && mop_len)

+			break;

+

+		last++;

+		/* Do not fetch more if the record will be too recent */

+		if (oldest <= last) {

+			if (!found_old) {

+				oldest = mdb_find_oldest(txn);

+				env->me_pgoldest = oldest;

+				found_old = 1;

+			}

+			if (oldest <= last)

+				break;

+		}

+		rc = mdb_cursor_get(&m2, &key, NULL, op);

+		if (rc) {

+			if (rc == MDB_NOTFOUND)

+				break;

+			goto fail;

+		}

+		last = *(txnid_t*)key.mv_data;

+		if (oldest <= last) {

+			if (!found_old) {

+				oldest = mdb_find_oldest(txn);

+				env->me_pgoldest = oldest;

+				found_old = 1;

+			}

+			if (oldest <= last)

+				break;

+		}

+		np = m2.mc_pg[m2.mc_top];

+		leaf = NODEPTR(np, m2.mc_ki[m2.mc_top]);

+		if ((rc = mdb_node_read(&m2, leaf, &data)) != MDB_SUCCESS)

+			return rc;

+

+		idl = (MDB_ID *) data.mv_data;

+		i = idl[0];

+		if (!mop) {

+			if (!(env->me_pghead = mop = mdb_midl_alloc(i))) {

+				rc = ENOMEM;

+				goto fail;

+			}

+		} else {

+			if ((rc = mdb_midl_need(&env->me_pghead, i)) != 0)

+				goto fail;

+			mop = env->me_pghead;

+		}

+		env->me_pglast = last;

+#if (MDB_DEBUG) > 1

+		DPRINTF(("IDL read txn %"Y"u root %"Y"u num %u",

+			last, txn->mt_dbs[FREE_DBI].md_root, i));

+		for (j = i; j; j--)

+			DPRINTF(("IDL %"Y"u", idl[j]));

+#endif

+		/* Merge in descending sorted order */

+		mdb_midl_xmerge(mop, idl);

+		mop_len = mop[0];

+	}

+

+	/* Use new pages from the map when nothing suitable in the freeDB */

+	i = 0;

+	pgno = txn->mt_next_pgno;

+	if (pgno + num >= env->me_maxpg) {

+			DPUTS("DB size maxed out");

+			rc = MDB_MAP_FULL;

+			goto fail;

+	}

+#if defined(_WIN32) && !defined(MDB_VL32)

+	if (!(env->me_flags & MDB_RDONLY)) {

+		void *p;

+		p = (MDB_page *)(env->me_map + env->me_psize * pgno);

+		p = VirtualAlloc(p, env->me_psize * num, MEM_COMMIT,

+			(env->me_flags & MDB_WRITEMAP) ? PAGE_READWRITE:

+			PAGE_READONLY);

+		if (!p) {

+			DPUTS("VirtualAlloc failed");

+			rc = ErrCode();

+			goto fail;

+		}

+	}

+#endif

+

+search_done:

+	if (env->me_flags & MDB_WRITEMAP) {

+		np = (MDB_page *)(env->me_map + env->me_psize * pgno);

+	} else {

+		if (!(np = mdb_page_malloc(txn, num))) {

+			rc = ENOMEM;

+			goto fail;

+		}

+	}

+	if (i) {

+		mop[0] = mop_len -= num;

+		/* Move any stragglers down */

+		for (j = i-num; j < mop_len; )

+			mop[++j] = mop[++i];

+	} else {

+		txn->mt_next_pgno = pgno + num;

+	}

+	np->mp_pgno = pgno;

+	mdb_page_dirty(txn, np);

+	*mp = np;

+

+	return MDB_SUCCESS;

+

+fail:

+	txn->mt_flags |= MDB_TXN_ERROR;

+	return rc;

+}

+

+/** Copy the used portions of a non-overflow page.

+ * @param[in] dst page to copy into

+ * @param[in] src page to copy from

+ * @param[in] psize size of a page

+ */

+static void

+mdb_page_copy(MDB_page *dst, MDB_page *src, unsigned int psize)

+{

+	enum { Align = sizeof(pgno_t) };

+	indx_t upper = src->mp_upper, lower = src->mp_lower, unused = upper-lower;

+

+	/* If page isn't full, just copy the used portion. Adjust

+	 * alignment so memcpy may copy words instead of bytes.

+	 */

+	if ((unused &= -Align) && !IS_LEAF2(src)) {

+		upper = (upper + PAGEBASE) & -Align;

+		memcpy(dst, src, (lower + PAGEBASE + (Align-1)) & -Align);

+		memcpy((pgno_t *)((char *)dst+upper), (pgno_t *)((char *)src+upper),

+			psize - upper);

+	} else {

+		memcpy(dst, src, psize - unused);

+	}

+}

+

+/** Pull a page off the txn's spill list, if present.

+ * If a page being referenced was spilled to disk in this txn, bring

+ * it back and make it dirty/writable again.

+ * @param[in] txn the transaction handle.

+ * @param[in] mp the page being referenced. It must not be dirty.

+ * @param[out] ret the writable page, if any. ret is unchanged if

+ * mp wasn't spilled.

+ */

+static int

+mdb_page_unspill(MDB_txn *txn, MDB_page *mp, MDB_page **ret)

+{

+	MDB_env *env = txn->mt_env;

+	const MDB_txn *tx2;

+	unsigned x;

+	pgno_t pgno = mp->mp_pgno, pn = pgno << 1;

+

+	for (tx2 = txn; tx2; tx2=tx2->mt_parent) {

+		if (!tx2->mt_spill_pgs)

+			continue;

+		x = mdb_midl_search(tx2->mt_spill_pgs, pn);

+		if (x <= tx2->mt_spill_pgs[0] && tx2->mt_spill_pgs[x] == pn) {

+			MDB_page *np;

+			int num;

+			if (txn->mt_dirty_room == 0)

+				return MDB_TXN_FULL;

+			if (IS_OVERFLOW(mp))

+				num = mp->mp_pages;

+			else

+				num = 1;

+			if (env->me_flags & MDB_WRITEMAP) {

+				np = mp;

+			} else {

+				np = mdb_page_malloc(txn, num);

+				if (!np)

+					return ENOMEM;

+				if (num > 1)

+					memcpy(np, mp, num * env->me_psize);

+				else

+					mdb_page_copy(np, mp, env->me_psize);

+			}

+			if (tx2 == txn) {

+				/* If in current txn, this page is no longer spilled.

+				 * If it happens to be the last page, truncate the spill list.

+				 * Otherwise mark it as deleted by setting the LSB.

+				 */

+				if (x == txn->mt_spill_pgs[0])

+					txn->mt_spill_pgs[0]--;

+				else

+					txn->mt_spill_pgs[x] |= 1;

+			}	/* otherwise, if belonging to a parent txn, the

+				 * page remains spilled until child commits

+				 */

+

+			mdb_page_dirty(txn, np);

+			np->mp_flags |= P_DIRTY;

+			*ret = np;

+			break;

+		}

+	}

+	return MDB_SUCCESS;

+}

+

+/** Touch a page: make it dirty and re-insert into tree with updated pgno.

+ * @param[in] mc cursor pointing to the page to be touched

+ * @return 0 on success, non-zero on failure.

+ */

+static int

+mdb_page_touch(MDB_cursor *mc)

+{

+	MDB_page *mp = mc->mc_pg[mc->mc_top], *np;

+	MDB_txn *txn = mc->mc_txn;

+	MDB_cursor *m2, *m3;

+	pgno_t	pgno;

+	int rc;

+

+	if (!F_ISSET(mp->mp_flags, P_DIRTY)) {

+		if (txn->mt_flags & MDB_TXN_SPILLS) {

+			np = NULL;

+			rc = mdb_page_unspill(txn, mp, &np);

+			if (rc)

+				goto fail;

+			if (np)

+				goto done;

+		}

+		if ((rc = mdb_midl_need(&txn->mt_free_pgs, 1)) ||

+			(rc = mdb_page_alloc(mc, 1, &np)))

+			goto fail;

+		pgno = np->mp_pgno;

+		DPRINTF(("touched db %d page %"Y"u -> %"Y"u", DDBI(mc),

+			mp->mp_pgno, pgno));

+		mdb_cassert(mc, mp->mp_pgno != pgno);

+		mdb_midl_xappend(txn->mt_free_pgs, mp->mp_pgno);

+		/* Update the parent page, if any, to point to the new page */

+		if (mc->mc_top) {

+			MDB_page *parent = mc->mc_pg[mc->mc_top-1];

+			MDB_node *node = NODEPTR(parent, mc->mc_ki[mc->mc_top-1]);

+			SETPGNO(node, pgno);

+		} else {

+			mc->mc_db->md_root = pgno;

+		}

+	} else if (txn->mt_parent && !IS_SUBP(mp)) {

+		MDB_ID2 mid, *dl = txn->mt_u.dirty_list;

+		pgno = mp->mp_pgno;

+		/* If txn has a parent, make sure the page is in our

+		 * dirty list.

+		 */

+		if (dl[0].mid) {

+			unsigned x = mdb_mid2l_search(dl, pgno);

+			if (x <= dl[0].mid && dl[x].mid == pgno) {

+				if (mp != dl[x].mptr) { /* bad cursor? */

+					mc->mc_flags &= ~(C_INITIALIZED|C_EOF);

+					txn->mt_flags |= MDB_TXN_ERROR;

+					return MDB_CORRUPTED;

+				}

+				return 0;

+			}

+		}

+		mdb_cassert(mc, dl[0].mid < MDB_IDL_UM_MAX);

+		/* No - copy it */

+		np = mdb_page_malloc(txn, 1);

+		if (!np)

+			return ENOMEM;

+		mid.mid = pgno;

+		mid.mptr = np;

+		rc = mdb_mid2l_insert(dl, &mid);

+		mdb_cassert(mc, rc == 0);

+	} else {

+		return 0;

+	}

+

+	mdb_page_copy(np, mp, txn->mt_env->me_psize);

+	np->mp_pgno = pgno;

+	np->mp_flags |= P_DIRTY;

+

+done:

+	/* Adjust cursors pointing to mp */

+	mc->mc_pg[mc->mc_top] = np;

+	m2 = txn->mt_cursors[mc->mc_dbi];

+	if (mc->mc_flags & C_SUB) {

+		for (; m2; m2=m2->mc_next) {

+			m3 = &m2->mc_xcursor->mx_cursor;

+			if (m3->mc_snum < mc->mc_snum) continue;

+			if (m3->mc_pg[mc->mc_top] == mp)

+				m3->mc_pg[mc->mc_top] = np;

+		}

+	} else {

+		for (; m2; m2=m2->mc_next) {

+			if (m2->mc_snum < mc->mc_snum) continue;

+			if (m2 == mc) continue;

+			if (m2->mc_pg[mc->mc_top] == mp) {

+				m2->mc_pg[mc->mc_top] = np;

+				if ((mc->mc_db->md_flags & MDB_DUPSORT) &&

+					IS_LEAF(np) &&

+					(m2->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED))

+				{

+					MDB_node *leaf = NODEPTR(np, m2->mc_ki[mc->mc_top]);

+					if ((leaf->mn_flags & (F_DUPDATA|F_SUBDATA)) == F_DUPDATA)

+						m2->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(leaf);

+				}

+			}

+		}

+	}

+	MDB_PAGE_UNREF(mc->mc_txn, mp);

+	return 0;

+

+fail:

+	txn->mt_flags |= MDB_TXN_ERROR;

+	return rc;

+}

+

+int

+mdb_env_sync0(MDB_env *env, int force, pgno_t numpgs)

+{

+	int rc = 0;

+	if (env->me_flags & MDB_RDONLY)

+		return EACCES;

+	if (force || !F_ISSET(env->me_flags, MDB_NOSYNC)) {

+		if (env->me_flags & MDB_WRITEMAP) {

+			int flags = ((env->me_flags & MDB_MAPASYNC) && !force)

+				? MS_ASYNC : MS_SYNC;

+			if (MDB_MSYNC(env->me_map, env->me_psize * numpgs, flags))

+				rc = ErrCode();

+#ifdef _WIN32

+			else if (flags == MS_SYNC && MDB_FDATASYNC(env->me_fd))

+				rc = ErrCode();

+#endif

+		} else {

+#ifdef BROKEN_FDATASYNC

+			if (env->me_flags & MDB_FSYNCONLY) {

+				if (fsync(env->me_fd))

+					rc = ErrCode();

+			} else

+#endif

+			if (MDB_FDATASYNC(env->me_fd))

+				rc = ErrCode();

+		}

+	}

+	return rc;

+}

+

+int

+mdb_env_sync(MDB_env *env, int force)

+{

+	MDB_meta *m = mdb_env_pick_meta(env);

+	return mdb_env_sync0(env, force, m->mm_last_pg+1);

+}

+

+/** Back up parent txn's cursors, then grab the originals for tracking */

+static int

+mdb_cursor_shadow(MDB_txn *src, MDB_txn *dst)

+{

+	MDB_cursor *mc, *bk;

+	MDB_xcursor *mx;

+	size_t size;

+	int i;

+

+	for (i = src->mt_numdbs; --i >= 0; ) {

+		if ((mc = src->mt_cursors[i]) != NULL) {

+			size = sizeof(MDB_cursor);

+			if (mc->mc_xcursor)

+				size += sizeof(MDB_xcursor);

+			for (; mc; mc = bk->mc_next) {

+				bk = malloc(size);

+				if (!bk)

+					return ENOMEM;

+				*bk = *mc;

+				mc->mc_backup = bk;

+				mc->mc_db = &dst->mt_dbs[i];

+				/* Kill pointers into src to reduce abuse: The

+				 * user may not use mc until dst ends. But we need a valid

+				 * txn pointer here for cursor fixups to keep working.

+				 */

+				mc->mc_txn    = dst;

+				mc->mc_dbflag = &dst->mt_dbflags[i];

+				if ((mx = mc->mc_xcursor) != NULL) {

+					*(MDB_xcursor *)(bk+1) = *mx;

+					mx->mx_cursor.mc_txn = dst;

+				}

+				mc->mc_next = dst->mt_cursors[i];

+				dst->mt_cursors[i] = mc;

+			}

+		}

+	}

+	return MDB_SUCCESS;

+}

+

+/** Close this write txn's cursors, give parent txn's cursors back to parent.

+ * @param[in] txn the transaction handle.

+ * @param[in] merge true to keep changes to parent cursors, false to revert.

+ * @return 0 on success, non-zero on failure.

+ */

+static void

+mdb_cursors_close(MDB_txn *txn, unsigned merge)

+{

+	MDB_cursor **cursors = txn->mt_cursors, *mc, *next, *bk;

+	MDB_xcursor *mx;

+	int i;

+

+	for (i = txn->mt_numdbs; --i >= 0; ) {

+		for (mc = cursors[i]; mc; mc = next) {

+			next = mc->mc_next;

+			if ((bk = mc->mc_backup) != NULL) {

+				if (merge) {

+					/* Commit changes to parent txn */

+					mc->mc_next = bk->mc_next;

+					mc->mc_backup = bk->mc_backup;

+					mc->mc_txn = bk->mc_txn;

+					mc->mc_db = bk->mc_db;

+					mc->mc_dbflag = bk->mc_dbflag;

+					if ((mx = mc->mc_xcursor) != NULL)

+						mx->mx_cursor.mc_txn = bk->mc_txn;

+				} else {

+					/* Abort nested txn */

+					*mc = *bk;

+					if ((mx = mc->mc_xcursor) != NULL)

+						*mx = *(MDB_xcursor *)(bk+1);

+				}

+				mc = bk;

+			}

+			/* Only malloced cursors are permanently tracked. */

+			free(mc);

+		}

+		cursors[i] = NULL;

+	}

+}

+

+#if !(MDB_PIDLOCK)		/* Currently the same as defined(_WIN32) */

+enum Pidlock_op {

+	Pidset, Pidcheck

+};

+#else

+enum Pidlock_op {

+	Pidset = F_SETLK, Pidcheck = F_GETLK

+};

+#endif

+

+/** Set or check a pid lock. Set returns 0 on success.

+ * Check returns 0 if the process is certainly dead, nonzero if it may

+ * be alive (the lock exists or an error happened so we do not know).

+ *

+ * On Windows Pidset is a no-op, we merely check for the existence

+ * of the process with the given pid. On POSIX we use a single byte

+ * lock on the lockfile, set at an offset equal to the pid.

+ */

+static int

+mdb_reader_pid(MDB_env *env, enum Pidlock_op op, MDB_PID_T pid)

+{

+#if !(MDB_PIDLOCK)		/* Currently the same as defined(_WIN32) */

+	int ret = 0;

+	HANDLE h;

+	if (op == Pidcheck) {

+		h = OpenProcess(env->me_pidquery, FALSE, pid);

+		/* No documented "no such process" code, but other program use this: */

+		if (!h)

+			return ErrCode() != ERROR_INVALID_PARAMETER;

+		/* A process exists until all handles to it close. Has it exited? */

+		ret = WaitForSingleObject(h, 0) != 0;

+		CloseHandle(h);

+	}

+	return ret;

+#else

+	for (;;) {

+		int rc;

+		struct flock lock_info;

+		memset(&lock_info, 0, sizeof(lock_info));

+		lock_info.l_type = F_WRLCK;

+		lock_info.l_whence = SEEK_SET;

+		lock_info.l_start = pid;

+		lock_info.l_len = 1;

+		if ((rc = fcntl(env->me_lfd, op, &lock_info)) == 0) {

+			if (op == F_GETLK && lock_info.l_type != F_UNLCK)

+				rc = -1;

+		} else if ((rc = ErrCode()) == EINTR) {

+			continue;

+		}

+		return rc;

+	}

+#endif

+}

+

+/** Common code for #mdb_txn_begin() and #mdb_txn_renew().

+ * @param[in] txn the transaction handle to initialize

+ * @return 0 on success, non-zero on failure.

+ */

+static int

+mdb_txn_renew0(MDB_txn *txn)

+{

+	MDB_env *env = txn->mt_env;

+	MDB_txninfo *ti = env->me_txns;

+	MDB_meta *meta;

+	unsigned int i, nr, flags = txn->mt_flags;

+	uint16_t x;

+	int rc, new_notls = 0;

+

+	if ((flags &= MDB_TXN_RDONLY) != 0) {

+		if (!ti) {

+			meta = mdb_env_pick_meta(env);

+			txn->mt_txnid = meta->mm_txnid;

+			txn->mt_u.reader = NULL;

+		} else {

+			MDB_reader *r = (env->me_flags & MDB_NOTLS) ? txn->mt_u.reader :

+				pthread_getspecific(env->me_txkey);

+			if (r) {

+				if (r->mr_pid != env->me_pid || r->mr_txnid != (txnid_t)-1)

+					return MDB_BAD_RSLOT;

+			} else {

+				MDB_PID_T pid = env->me_pid;

+				MDB_THR_T tid = pthread_self();

+				mdb_mutexref_t rmutex = env->me_rmutex;

+

+				if (!env->me_live_reader) {

+					rc = mdb_reader_pid(env, Pidset, pid);

+					if (rc)

+						return rc;

+					env->me_live_reader = 1;

+				}

+

+				if (LOCK_MUTEX(rc, env, rmutex))

+					return rc;

+				nr = ti->mti_numreaders;

+				for (i=0; i<nr; i++)

+					if (ti->mti_readers[i].mr_pid == 0)

+						break;

+				if (i == env->me_maxreaders) {

+					UNLOCK_MUTEX(rmutex);

+					return MDB_READERS_FULL;

+				}

+				r = &ti->mti_readers[i];

+				/* Claim the reader slot, carefully since other code

+				 * uses the reader table un-mutexed: First reset the

+				 * slot, next publish it in mti_numreaders.  After

+				 * that, it is safe for mdb_env_close() to touch it.

+				 * When it will be closed, we can finally claim it.

+				 */

+				r->mr_pid = 0;

+				r->mr_txnid = (txnid_t)-1;

+				r->mr_tid = tid;

+				if (i == nr)

+					ti->mti_numreaders = ++nr;

+				env->me_close_readers = nr;

+				r->mr_pid = pid;

+				UNLOCK_MUTEX(rmutex);

+

+				new_notls = (env->me_flags & MDB_NOTLS);

+				if (!new_notls && (rc=pthread_setspecific(env->me_txkey, r))) {

+					r->mr_pid = 0;

+					return rc;

+				}

+			}

+			do /* LY: Retry on a race, ITS#7970. */

+				r->mr_txnid = ti->mti_txnid;

+			while(r->mr_txnid != ti->mti_txnid);

+			txn->mt_txnid = r->mr_txnid;

+			txn->mt_u.reader = r;

+			meta = env->me_metas[txn->mt_txnid & 1];

+		}

+

+	} else {

+		/* Not yet touching txn == env->me_txn0, it may be active */

+		if (ti) {

+			if (LOCK_MUTEX(rc, env, env->me_wmutex))

+				return rc;

+			txn->mt_txnid = ti->mti_txnid;

+			meta = env->me_metas[txn->mt_txnid & 1];

+		} else {

+			meta = mdb_env_pick_meta(env);

+			txn->mt_txnid = meta->mm_txnid;

+		}

+		txn->mt_txnid++;

+#if MDB_DEBUG

+		if (txn->mt_txnid == mdb_debug_start)

+			mdb_debug = 1;

+#endif

+		txn->mt_child = NULL;

+		txn->mt_loose_pgs = NULL;

+		txn->mt_loose_count = 0;

+		txn->mt_dirty_room = MDB_IDL_UM_MAX;

+		txn->mt_u.dirty_list = env->me_dirty_list;

+		txn->mt_u.dirty_list[0].mid = 0;

+		txn->mt_free_pgs = env->me_free_pgs;

+		txn->mt_free_pgs[0] = 0;

+		txn->mt_spill_pgs = NULL;

+		env->me_txn = txn;

+		memcpy(txn->mt_dbiseqs, env->me_dbiseqs, env->me_maxdbs * sizeof(unsigned int));

+	}

+

+	/* Copy the DB info and flags */

+	memcpy(txn->mt_dbs, meta->mm_dbs, CORE_DBS * sizeof(MDB_db));

+

+	/* Moved to here to avoid a data race in read TXNs */

+	txn->mt_next_pgno = meta->mm_last_pg+1;

+#ifdef MDB_VL32

+	txn->mt_last_pgno = txn->mt_next_pgno - 1;

+#endif

+

+	txn->mt_flags = flags;

+

+	/* Setup db info */

+	txn->mt_numdbs = env->me_numdbs;

+	for (i=CORE_DBS; i<txn->mt_numdbs; i++) {

+		x = env->me_dbflags[i];

+		txn->mt_dbs[i].md_flags = x & PERSISTENT_FLAGS;

+		txn->mt_dbflags[i] = (x & MDB_VALID) ? DB_VALID|DB_USRVALID|DB_STALE : 0;

+	}

+	txn->mt_dbflags[MAIN_DBI] = DB_VALID|DB_USRVALID;

+	txn->mt_dbflags[FREE_DBI] = DB_VALID;

+

+	if (env->me_flags & MDB_FATAL_ERROR) {

+		DPUTS("environment had fatal error, must shutdown!");

+		rc = MDB_PANIC;

+	} else if (env->me_maxpg < txn->mt_next_pgno) {

+		rc = MDB_MAP_RESIZED;

+	} else {

+		return MDB_SUCCESS;

+	}

+	mdb_txn_end(txn, new_notls /*0 or MDB_END_SLOT*/ | MDB_END_FAIL_BEGIN);

+	return rc;

+}

+

+int

+mdb_txn_renew(MDB_txn *txn)

+{

+	int rc;

+

+	if (!txn || !F_ISSET(txn->mt_flags, MDB_TXN_RDONLY|MDB_TXN_FINISHED))

+		return EINVAL;

+

+	rc = mdb_txn_renew0(txn);

+	if (rc == MDB_SUCCESS) {

+		DPRINTF(("renew txn %"Y"u%c %p on mdbenv %p, root page %"Y"u",

+			txn->mt_txnid, (txn->mt_flags & MDB_TXN_RDONLY) ? 'r' : 'w',

+			(void *)txn, (void *)txn->mt_env, txn->mt_dbs[MAIN_DBI].md_root));

+	}

+	return rc;

+}

+

+int

+mdb_txn_begin(MDB_env *env, MDB_txn *parent, unsigned int flags, MDB_txn **ret)

+{

+	MDB_txn *txn;

+	MDB_ntxn *ntxn;

+	int rc, size, tsize;

+

+	flags &= MDB_TXN_BEGIN_FLAGS;

+	flags |= env->me_flags & MDB_WRITEMAP;

+

+	if (env->me_flags & MDB_RDONLY & ~flags) /* write txn in RDONLY env */

+		return EACCES;

+

+	if (parent) {

+		/* Nested transactions: Max 1 child, write txns only, no writemap */

+		flags |= parent->mt_flags;

+		if (flags & (MDB_RDONLY|MDB_WRITEMAP|MDB_TXN_BLOCKED)) {

+			return (parent->mt_flags & MDB_TXN_RDONLY) ? EINVAL : MDB_BAD_TXN;

+		}

+		/* Child txns save MDB_pgstate and use own copy of cursors */

+		size = env->me_maxdbs * (sizeof(MDB_db)+sizeof(MDB_cursor *)+1);

+		size += tsize = sizeof(MDB_ntxn);

+	} else if (flags & MDB_RDONLY) {

+		size = env->me_maxdbs * (sizeof(MDB_db)+1);

+		size += tsize = sizeof(MDB_txn);

+	} else {

+		/* Reuse preallocated write txn. However, do not touch it until

+		 * mdb_txn_renew0() succeeds, since it currently may be active.

+		 */

+		txn = env->me_txn0;

+		goto renew;

+	}

+	if ((txn = calloc(1, size)) == NULL) {

+		DPRINTF(("calloc: %s", strerror(errno)));

+		return ENOMEM;

+	}

+#ifdef MDB_VL32

+	if (!parent) {

+		txn->mt_rpages = malloc(MDB_TRPAGE_SIZE * sizeof(MDB_ID3));

+		if (!txn->mt_rpages) {

+			free(txn);

+			return ENOMEM;

+		}

+		txn->mt_rpages[0].mid = 0;

+		txn->mt_rpcheck = MDB_TRPAGE_SIZE/2;

+	}

+#endif

+	txn->mt_dbxs = env->me_dbxs;	/* static */

+	txn->mt_dbs = (MDB_db *) ((char *)txn + tsize);

+	txn->mt_dbflags = (unsigned char *)txn + size - env->me_maxdbs;

+	txn->mt_flags = flags;

+	txn->mt_env = env;

+

+	if (parent) {

+		unsigned int i;

+		txn->mt_cursors = (MDB_cursor **)(txn->mt_dbs + env->me_maxdbs);

+		txn->mt_dbiseqs = parent->mt_dbiseqs;

+		txn->mt_u.dirty_list = malloc(sizeof(MDB_ID2)*MDB_IDL_UM_SIZE);

+		if (!txn->mt_u.dirty_list ||

+			!(txn->mt_free_pgs = mdb_midl_alloc(MDB_IDL_UM_MAX)))

+		{

+			free(txn->mt_u.dirty_list);

+			free(txn);

+			return ENOMEM;

+		}

+		txn->mt_txnid = parent->mt_txnid;

+		txn->mt_dirty_room = parent->mt_dirty_room;

+		txn->mt_u.dirty_list[0].mid = 0;

+		txn->mt_spill_pgs = NULL;

+		txn->mt_next_pgno = parent->mt_next_pgno;

+		parent->mt_flags |= MDB_TXN_HAS_CHILD;

+		parent->mt_child = txn;

+		txn->mt_parent = parent;

+		txn->mt_numdbs = parent->mt_numdbs;

+#ifdef MDB_VL32

+		txn->mt_rpages = parent->mt_rpages;

+#endif

+		memcpy(txn->mt_dbs, parent->mt_dbs, txn->mt_numdbs * sizeof(MDB_db));

+		/* Copy parent's mt_dbflags, but clear DB_NEW */

+		for (i=0; i<txn->mt_numdbs; i++)

+			txn->mt_dbflags[i] = parent->mt_dbflags[i] & ~DB_NEW;

+		rc = 0;

+		ntxn = (MDB_ntxn *)txn;

+		ntxn->mnt_pgstate = env->me_pgstate; /* save parent me_pghead & co */

+		if (env->me_pghead) {

+			size = MDB_IDL_SIZEOF(env->me_pghead);

+			env->me_pghead = mdb_midl_alloc(env->me_pghead[0]);

+			if (env->me_pghead)

+				memcpy(env->me_pghead, ntxn->mnt_pgstate.mf_pghead, size);

+			else

+				rc = ENOMEM;

+		}

+		if (!rc)

+			rc = mdb_cursor_shadow(parent, txn);

+		if (rc)

+			mdb_txn_end(txn, MDB_END_FAIL_BEGINCHILD);

+	} else { /* MDB_RDONLY */

+		txn->mt_dbiseqs = env->me_dbiseqs;

+renew:

+		rc = mdb_txn_renew0(txn);

+	}

+	if (rc) {

+		if (txn != env->me_txn0) {

+#ifdef MDB_VL32

+			free(txn->mt_rpages);

+#endif

+			free(txn);

+		}

+	} else {

+		txn->mt_flags |= flags;	/* could not change txn=me_txn0 earlier */

+		*ret = txn;

+		DPRINTF(("begin txn %"Y"u%c %p on mdbenv %p, root page %"Y"u",

+			txn->mt_txnid, (flags & MDB_RDONLY) ? 'r' : 'w',

+			(void *) txn, (void *) env, txn->mt_dbs[MAIN_DBI].md_root));

+	}

+

+	return rc;

+}

+

+MDB_env *

+mdb_txn_env(MDB_txn *txn)

+{

+	if(!txn) return NULL;

+	return txn->mt_env;

+}

+

+mdb_size_t

+mdb_txn_id(MDB_txn *txn)

+{

+    if(!txn) return 0;

+    return txn->mt_txnid;

+}

+

+/** Export or close DBI handles opened in this txn. */

+static void

+mdb_dbis_update(MDB_txn *txn, int keep)

+{

+	int i;

+	MDB_dbi n = txn->mt_numdbs;

+	MDB_env *env = txn->mt_env;

+	unsigned char *tdbflags = txn->mt_dbflags;

+

+	for (i = n; --i >= CORE_DBS;) {

+		if (tdbflags[i] & DB_NEW) {

+			if (keep) {

+				env->me_dbflags[i] = txn->mt_dbs[i].md_flags | MDB_VALID;

+			} else {

+				char *ptr = env->me_dbxs[i].md_name.mv_data;

+				if (ptr) {

+					env->me_dbxs[i].md_name.mv_data = NULL;

+					env->me_dbxs[i].md_name.mv_size = 0;

+					env->me_dbflags[i] = 0;

+					env->me_dbiseqs[i]++;

+					free(ptr);

+				}

+			}

+		}

+	}

+	if (keep && env->me_numdbs < n)

+		env->me_numdbs = n;

+}

+

+/** End a transaction, except successful commit of a nested transaction.

+ * May be called twice for readonly txns: First reset it, then abort.

+ * @param[in] txn the transaction handle to end

+ * @param[in] mode why and how to end the transaction

+ */

+static void

+mdb_txn_end(MDB_txn *txn, unsigned mode)

+{

+	MDB_env	*env = txn->mt_env;

+#if MDB_DEBUG

+	static const char *const names[] = MDB_END_NAMES;

+#endif

+

+	/* Export or close DBI handles opened in this txn */

+	mdb_dbis_update(txn, mode & MDB_END_UPDATE);

+

+	DPRINTF(("%s txn %"Y"u%c %p on mdbenv %p, root page %"Y"u",

+		names[mode & MDB_END_OPMASK],

+		txn->mt_txnid, (txn->mt_flags & MDB_TXN_RDONLY) ? 'r' : 'w',

+		(void *) txn, (void *)env, txn->mt_dbs[MAIN_DBI].md_root));

+

+	if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY)) {

+		if (txn->mt_u.reader) {

+			txn->mt_u.reader->mr_txnid = (txnid_t)-1;

+			if (!(env->me_flags & MDB_NOTLS)) {

+				txn->mt_u.reader = NULL; /* txn does not own reader */

+			} else if (mode & MDB_END_SLOT) {

+				txn->mt_u.reader->mr_pid = 0;

+				txn->mt_u.reader = NULL;

+			} /* else txn owns the slot until it does MDB_END_SLOT */

+		}

+		txn->mt_numdbs = 0;		/* prevent further DBI activity */

+		txn->mt_flags |= MDB_TXN_FINISHED;

+

+	} else if (!F_ISSET(txn->mt_flags, MDB_TXN_FINISHED)) {

+		pgno_t *pghead = env->me_pghead;

+

+		if (!(mode & MDB_END_UPDATE)) /* !(already closed cursors) */

+			mdb_cursors_close(txn, 0);

+		if (!(env->me_flags & MDB_WRITEMAP)) {

+			mdb_dlist_free(txn);

+		}

+

+		txn->mt_numdbs = 0;

+		txn->mt_flags = MDB_TXN_FINISHED;

+

+		if (!txn->mt_parent) {

+			mdb_midl_shrink(&txn->mt_free_pgs);

+			env->me_free_pgs = txn->mt_free_pgs;

+			/* me_pgstate: */

+			env->me_pghead = NULL;

+			env->me_pglast = 0;

+

+			env->me_txn = NULL;

+			mode = 0;	/* txn == env->me_txn0, do not free() it */

+

+			/* The writer mutex was locked in mdb_txn_begin. */

+			if (env->me_txns)

+				UNLOCK_MUTEX(env->me_wmutex);

+		} else {

+			txn->mt_parent->mt_child = NULL;

+			txn->mt_parent->mt_flags &= ~MDB_TXN_HAS_CHILD;

+			env->me_pgstate = ((MDB_ntxn *)txn)->mnt_pgstate;

+			mdb_midl_free(txn->mt_free_pgs);

+			mdb_midl_free(txn->mt_spill_pgs);

+			free(txn->mt_u.dirty_list);

+		}

+

+		mdb_midl_free(pghead);

+	}

+#ifdef MDB_VL32

+	if (!txn->mt_parent) {

+		MDB_ID3L el = env->me_rpages, tl = txn->mt_rpages;

+		unsigned i, x, n = tl[0].mid;

+		pthread_mutex_lock(&env->me_rpmutex);

+		for (i = 1; i <= n; i++) {

+			if (tl[i].mid & (MDB_RPAGE_CHUNK-1)) {

+				/* tmp overflow pages that we didn't share in env */

+				munmap(tl[i].mptr, tl[i].mcnt * env->me_psize);

+			} else {

+				x = mdb_mid3l_search(el, tl[i].mid);

+				if (tl[i].mptr == el[x].mptr) {

+					el[x].mref--;

+				} else {

+					/* another tmp overflow page */

+					munmap(tl[i].mptr, tl[i].mcnt * env->me_psize);

+				}

+			}

+		}

+		pthread_mutex_unlock(&env->me_rpmutex);

+		tl[0].mid = 0;

+		if (mode & MDB_END_FREE)

+			free(tl);

+	}

+#endif

+	if (mode & MDB_END_FREE)

+		free(txn);

+}

+

+void

+mdb_txn_reset(MDB_txn *txn)

+{

+	if (txn == NULL)

+		return;

+

+	/* This call is only valid for read-only txns */

+	if (!(txn->mt_flags & MDB_TXN_RDONLY))

+		return;

+

+	mdb_txn_end(txn, MDB_END_RESET);

+}

+

+void

+mdb_txn_abort(MDB_txn *txn)

+{

+	if (txn == NULL)

+		return;

+

+	if (txn->mt_child)

+		mdb_txn_abort(txn->mt_child);

+

+	mdb_txn_end(txn, MDB_END_ABORT|MDB_END_SLOT|MDB_END_FREE);

+}

+

+/** Save the freelist as of this transaction to the freeDB.

+ * This changes the freelist. Keep trying until it stabilizes.

+ *

+ * When (MDB_DEVEL) & 2, the changes do not affect #mdb_page_alloc(),

+ * it then uses the transaction's original snapshot of the freeDB.

+ */

+static int

+mdb_freelist_save(MDB_txn *txn)

+{

+	/* env->me_pghead[] can grow and shrink during this call.

+	 * env->me_pglast and txn->mt_free_pgs[] can only grow.

+	 * Page numbers cannot disappear from txn->mt_free_pgs[].

+	 */

+	MDB_cursor mc;

+	MDB_env	*env = txn->mt_env;

+	int rc, maxfree_1pg = env->me_maxfree_1pg, more = 1;

+	txnid_t	pglast = 0, head_id = 0;

+	pgno_t	freecnt = 0, *free_pgs, *mop;

+	ssize_t	head_room = 0, total_room = 0, mop_len, clean_limit;

+

+	mdb_cursor_init(&mc, txn, FREE_DBI, NULL);

+

+	if (env->me_pghead) {

+		/* Make sure first page of freeDB is touched and on freelist */

+		rc = mdb_page_search(&mc, NULL, MDB_PS_FIRST|MDB_PS_MODIFY);

+		if (rc && rc != MDB_NOTFOUND)

+			return rc;

+	}

+

+	if (!env->me_pghead && txn->mt_loose_pgs) {

+		/* Put loose page numbers in mt_free_pgs, since

+		 * we may be unable to return them to me_pghead.

+		 */

+		MDB_page *mp = txn->mt_loose_pgs;

+		if ((rc = mdb_midl_need(&txn->mt_free_pgs, txn->mt_loose_count)) != 0)

+			return rc;

+		for (; mp; mp = NEXT_LOOSE_PAGE(mp))

+			mdb_midl_xappend(txn->mt_free_pgs, mp->mp_pgno);

+		txn->mt_loose_pgs = NULL;

+		txn->mt_loose_count = 0;

+	}

+

+	/* MDB_RESERVE cancels meminit in ovpage malloc (when no WRITEMAP) */

+	clean_limit = (env->me_flags & (MDB_NOMEMINIT|MDB_WRITEMAP))

+		? SSIZE_MAX : maxfree_1pg;

+

+	for (;;) {

+		/* Come back here after each Put() in case freelist changed */

+		MDB_val key, data;

+		pgno_t *pgs;

+		ssize_t j;

+

+		/* If using records from freeDB which we have not yet

+		 * deleted, delete them and any we reserved for me_pghead.

+		 */

+		while (pglast < env->me_pglast) {

+			rc = mdb_cursor_first(&mc, &key, NULL);

+			if (rc)

+				return rc;

+			pglast = head_id = *(txnid_t *)key.mv_data;

+			total_room = head_room = 0;

+			mdb_tassert(txn, pglast <= env->me_pglast);

+			rc = mdb_cursor_del(&mc, 0);

+			if (rc)

+				return rc;

+		}

+

+		/* Save the IDL of pages freed by this txn, to a single record */

+		if (freecnt < txn->mt_free_pgs[0]) {

+			if (!freecnt) {

+				/* Make sure last page of freeDB is touched and on freelist */

+				rc = mdb_page_search(&mc, NULL, MDB_PS_LAST|MDB_PS_MODIFY);

+				if (rc && rc != MDB_NOTFOUND)

+					return rc;

+			}

+			free_pgs = txn->mt_free_pgs;

+			/* Write to last page of freeDB */

+			key.mv_size = sizeof(txn->mt_txnid);

+			key.mv_data = &txn->mt_txnid;

+			do {

+				freecnt = free_pgs[0];

+				data.mv_size = MDB_IDL_SIZEOF(free_pgs);

+				rc = mdb_cursor_put(&mc, &key, &data, MDB_RESERVE);

+				if (rc)

+					return rc;

+				/* Retry if mt_free_pgs[] grew during the Put() */

+				free_pgs = txn->mt_free_pgs;

+			} while (freecnt < free_pgs[0]);

+			mdb_midl_sort(free_pgs);

+			memcpy(data.mv_data, free_pgs, data.mv_size);

+#if (MDB_DEBUG) > 1

+			{

+				unsigned int i = free_pgs[0];

+				DPRINTF(("IDL write txn %"Y"u root %"Y"u num %u",

+					txn->mt_txnid, txn->mt_dbs[FREE_DBI].md_root, i));

+				for (; i; i--)

+					DPRINTF(("IDL %"Y"u", free_pgs[i]));

+			}

+#endif

+			continue;

+		}

+

+		mop = env->me_pghead;

+		mop_len = (mop ? mop[0] : 0) + txn->mt_loose_count;

+

+		/* Reserve records for me_pghead[]. Split it if multi-page,

+		 * to avoid searching freeDB for a page range. Use keys in

+		 * range [1,me_pglast]: Smaller than txnid of oldest reader.

+		 */

+		if (total_room >= mop_len) {

+			if (total_room == mop_len || --more < 0)

+				break;

+		} else if (head_room >= maxfree_1pg && head_id > 1) {

+			/* Keep current record (overflow page), add a new one */

+			head_id--;

+			head_room = 0;

+		}

+		/* (Re)write {key = head_id, IDL length = head_room} */

+		total_room -= head_room;

+		head_room = mop_len - total_room;

+		if (head_room > maxfree_1pg && head_id > 1) {

+			/* Overflow multi-page for part of me_pghead */

+			head_room /= head_id; /* amortize page sizes */

+			head_room += maxfree_1pg - head_room % (maxfree_1pg + 1);

+		} else if (head_room < 0) {

+			/* Rare case, not bothering to delete this record */

+			head_room = 0;

+		}

+		key.mv_size = sizeof(head_id);

+		key.mv_data = &head_id;

+		data.mv_size = (head_room + 1) * sizeof(pgno_t);

+		rc = mdb_cursor_put(&mc, &key, &data, MDB_RESERVE);

+		if (rc)

+			return rc;

+		/* IDL is initially empty, zero out at least the length */

+		pgs = (pgno_t *)data.mv_data;

+		j = head_room > clean_limit ? head_room : 0;

+		do {

+			pgs[j] = 0;

+		} while (--j >= 0);

+		total_room += head_room;

+	}

+

+	/* Return loose page numbers to me_pghead, though usually none are

+	 * left at this point.  The pages themselves remain in dirty_list.

+	 */

+	if (txn->mt_loose_pgs) {

+		MDB_page *mp = txn->mt_loose_pgs;

+		unsigned count = txn->mt_loose_count;

+		MDB_IDL loose;

+		/* Room for loose pages + temp IDL with same */

+		if ((rc = mdb_midl_need(&env->me_pghead, 2*count+1)) != 0)

+			return rc;

+		mop = env->me_pghead;

+		loose = mop + MDB_IDL_ALLOCLEN(mop) - count;

+		for (count = 0; mp; mp = NEXT_LOOSE_PAGE(mp))

+			loose[ ++count ] = mp->mp_pgno;

+		loose[0] = count;

+		mdb_midl_sort(loose);

+		mdb_midl_xmerge(mop, loose);

+		txn->mt_loose_pgs = NULL;

+		txn->mt_loose_count = 0;

+		mop_len = mop[0];

+	}

+

+	/* Fill in the reserved me_pghead records */

+	rc = MDB_SUCCESS;

+	if (mop_len) {

+		MDB_val key, data;

+

+		mop += mop_len;

+		rc = mdb_cursor_first(&mc, &key, &data);

+		for (; !rc; rc = mdb_cursor_next(&mc, &key, &data, MDB_NEXT)) {

+			txnid_t id = *(txnid_t *)key.mv_data;

+			ssize_t	len = (ssize_t)(data.mv_size / sizeof(MDB_ID)) - 1;

+			MDB_ID save;

+

+			mdb_tassert(txn, len >= 0 && id <= env->me_pglast);

+			key.mv_data = &id;

+			if (len > mop_len) {

+				len = mop_len;

+				data.mv_size = (len + 1) * sizeof(MDB_ID);

+			}

+			data.mv_data = mop -= len;

+			save = mop[0];

+			mop[0] = len;

+			rc = mdb_cursor_put(&mc, &key, &data, MDB_CURRENT);

+			mop[0] = save;

+			if (rc || !(mop_len -= len))

+				break;

+		}

+	}

+	return rc;

+}

+

+/** Flush (some) dirty pages to the map, after clearing their dirty flag.

+ * @param[in] txn the transaction that's being committed

+ * @param[in] keep number of initial pages in dirty_list to keep dirty.

+ * @return 0 on success, non-zero on failure.

+ */

+static int

+mdb_page_flush(MDB_txn *txn, int keep)

+{

+	MDB_env		*env = txn->mt_env;

+	MDB_ID2L	dl = txn->mt_u.dirty_list;

+	unsigned	psize = env->me_psize, j;

+	int			i, pagecount = dl[0].mid, rc;

+	size_t		size = 0;

+	off_t		pos = 0;

+	pgno_t		pgno = 0;

+	MDB_page	*dp = NULL;

+#ifdef _WIN32

+	OVERLAPPED	ov;

+#else

+	struct iovec iov[MDB_COMMIT_PAGES];

+	ssize_t		wsize = 0, wres;

+	off_t		wpos = 0, next_pos = 1; /* impossible pos, so pos != next_pos */

+	int			n = 0;

+#endif

+

+	j = i = keep;

+

+	if (env->me_flags & MDB_WRITEMAP) {

+		/* Clear dirty flags */

+		while (++i <= pagecount) {

+			dp = dl[i].mptr;

+			/* Don't flush this page yet */

+			if (dp->mp_flags & (P_LOOSE|P_KEEP)) {

+				dp->mp_flags &= ~P_KEEP;

+				dl[++j] = dl[i];

+				continue;

+			}

+			dp->mp_flags &= ~P_DIRTY;

+		}

+		goto done;

+	}

+

+	/* Write the pages */

+	for (;;) {

+		if (++i <= pagecount) {

+			dp = dl[i].mptr;

+			/* Don't flush this page yet */

+			if (dp->mp_flags & (P_LOOSE|P_KEEP)) {

+				dp->mp_flags &= ~P_KEEP;

+				dl[i].mid = 0;

+				continue;

+			}

+			pgno = dl[i].mid;

+			/* clear dirty flag */

+			dp->mp_flags &= ~P_DIRTY;

+			pos = pgno * psize;

+			size = psize;

+			if (IS_OVERFLOW(dp)) size *= dp->mp_pages;

+		}

+#ifdef _WIN32

+		else break;

+

+		/* Windows actually supports scatter/gather I/O, but only on

+		 * unbuffered file handles. Since we're relying on the OS page

+		 * cache for all our data, that's self-defeating. So we just

+		 * write pages one at a time. We use the ov structure to set

+		 * the write offset, to at least save the overhead of a Seek

+		 * system call.

+		 */

+		DPRINTF(("committing page %"Z"u", pgno));

+		memset(&ov, 0, sizeof(ov));

+		ov.Offset = pos & 0xffffffff;

+		ov.OffsetHigh = pos >> 16 >> 16;

+		if (!WriteFile(env->me_fd, dp, size, NULL, &ov)) {

+			rc = ErrCode();

+			DPRINTF(("WriteFile: %d", rc));

+			return rc;

+		}

+#else

+		/* Write up to MDB_COMMIT_PAGES dirty pages at a time. */

+		if (pos!=next_pos || n==MDB_COMMIT_PAGES || wsize+size>MAX_WRITE) {

+			if (n) {

+retry_write:

+				/* Write previous page(s) */

+#ifdef MDB_USE_PWRITEV

+				wres = pwritev(env->me_fd, iov, n, wpos);

+#else

+				if (n == 1) {

+					wres = pwrite(env->me_fd, iov[0].iov_base, wsize, wpos);

+				} else {

+retry_seek:

+					if (lseek(env->me_fd, wpos, SEEK_SET) == -1) {

+						rc = ErrCode();

+						if (rc == EINTR)

+							goto retry_seek;

+						DPRINTF(("lseek: %s", strerror(rc)));

+						return rc;

+					}

+					wres = writev(env->me_fd, iov, n);

+				}

+#endif

+				if (wres != wsize) {

+					if (wres < 0) {

+						rc = ErrCode();

+						if (rc == EINTR)

+							goto retry_write;

+						DPRINTF(("Write error: %s", strerror(rc)));

+					} else {

+						rc = EIO; /* TODO: Use which error code? */

+						DPUTS("short write, filesystem full?");

+					}

+					return rc;

+				}

+				n = 0;

+			}

+			if (i > pagecount)

+				break;

+			wpos = pos;

+			wsize = 0;

+		}

+		DPRINTF(("committing page %"Y"u", pgno));

+		next_pos = pos + size;

+		iov[n].iov_len = size;

+		iov[n].iov_base = (char *)dp;

+		wsize += size;

+		n++;

+#endif	/* _WIN32 */

+	}

+#ifdef MDB_VL32

+	if (pgno > txn->mt_last_pgno)

+		txn->mt_last_pgno = pgno;

+#endif

+

+	/* MIPS has cache coherency issues, this is a no-op everywhere else

+	 * Note: for any size >= on-chip cache size, entire on-chip cache is

+	 * flushed.

+	 */

+	CACHEFLUSH(env->me_map, txn->mt_next_pgno * env->me_psize, DCACHE);

+

+	for (i = keep; ++i <= pagecount; ) {

+		dp = dl[i].mptr;

+		/* This is a page we skipped above */

+		if (!dl[i].mid) {

+			dl[++j] = dl[i];

+			dl[j].mid = dp->mp_pgno;

+			continue;

+		}

+		mdb_dpage_free(env, dp);

+	}

+

+done:

+	i--;

+	txn->mt_dirty_room += i - j;

+	dl[0].mid = j;

+	return MDB_SUCCESS;

+}

+

+int

+mdb_txn_commit(MDB_txn *txn)

+{

+	int		rc;

+	unsigned int i, end_mode;

+	MDB_env	*env;

+

+	if (txn == NULL)

+		return EINVAL;

+

+	/* mdb_txn_end() mode for a commit which writes nothing */

+	end_mode = MDB_END_EMPTY_COMMIT|MDB_END_UPDATE|MDB_END_SLOT|MDB_END_FREE;

+

+	if (txn->mt_child) {

+		rc = mdb_txn_commit(txn->mt_child);

+		if (rc)

+			goto fail;

+	}

+

+	env = txn->mt_env;

+

+	if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY)) {

+		goto done;

+	}

+

+	if (txn->mt_flags & (MDB_TXN_FINISHED|MDB_TXN_ERROR)) {

+		DPUTS("txn has failed/finished, can't commit");

+		if (txn->mt_parent)

+			txn->mt_parent->mt_flags |= MDB_TXN_ERROR;

+		rc = MDB_BAD_TXN;

+		goto fail;

+	}

+

+	if (txn->mt_parent) {

+		MDB_txn *parent = txn->mt_parent;

+		MDB_page **lp;

+		MDB_ID2L dst, src;

+		MDB_IDL pspill;

+		unsigned x, y, len, ps_len;

+

+		/* Append our free list to parent's */

+		rc = mdb_midl_append_list(&parent->mt_free_pgs, txn->mt_free_pgs);

+		if (rc)

+			goto fail;

+		mdb_midl_free(txn->mt_free_pgs);

+		/* Failures after this must either undo the changes

+		 * to the parent or set MDB_TXN_ERROR in the parent.

+		 */

+

+		parent->mt_next_pgno = txn->mt_next_pgno;

+		parent->mt_flags = txn->mt_flags;

+

+		/* Merge our cursors into parent's and close them */

+		mdb_cursors_close(txn, 1);

+

+		/* Update parent's DB table. */

+		memcpy(parent->mt_dbs, txn->mt_dbs, txn->mt_numdbs * sizeof(MDB_db));

+		parent->mt_numdbs = txn->mt_numdbs;

+		parent->mt_dbflags[FREE_DBI] = txn->mt_dbflags[FREE_DBI];

+		parent->mt_dbflags[MAIN_DBI] = txn->mt_dbflags[MAIN_DBI];

+		for (i=CORE_DBS; i<txn->mt_numdbs; i++) {

+			/* preserve parent's DB_NEW status */

+			x = parent->mt_dbflags[i] & DB_NEW;

+			parent->mt_dbflags[i] = txn->mt_dbflags[i] | x;

+		}

+

+		dst = parent->mt_u.dirty_list;

+		src = txn->mt_u.dirty_list;

+		/* Remove anything in our dirty list from parent's spill list */

+		if ((pspill = parent->mt_spill_pgs) && (ps_len = pspill[0])) {

+			x = y = ps_len;

+			pspill[0] = (pgno_t)-1;

+			/* Mark our dirty pages as deleted in parent spill list */

+			for (i=0, len=src[0].mid; ++i <= len; ) {

+				MDB_ID pn = src[i].mid << 1;

+				while (pn > pspill[x])

+					x--;

+				if (pn == pspill[x]) {

+					pspill[x] = 1;

+					y = --x;

+				}

+			}

+			/* Squash deleted pagenums if we deleted any */

+			for (x=y; ++x <= ps_len; )

+				if (!(pspill[x] & 1))

+					pspill[++y] = pspill[x];

+			pspill[0] = y;

+		}

+

+		/* Remove anything in our spill list from parent's dirty list */

+		if (txn->mt_spill_pgs && txn->mt_spill_pgs[0]) {

+			for (i=1; i<=txn->mt_spill_pgs[0]; i++) {

+				MDB_ID pn = txn->mt_spill_pgs[i];

+				if (pn & 1)

+					continue;	/* deleted spillpg */

+				pn >>= 1;

+				y = mdb_mid2l_search(dst, pn);

+				if (y <= dst[0].mid && dst[y].mid == pn) {

+					free(dst[y].mptr);

+					while (y < dst[0].mid) {

+						dst[y] = dst[y+1];

+						y++;

+					}

+					dst[0].mid--;

+				}

+			}

+		}

+

+		/* Find len = length of merging our dirty list with parent's */

+		x = dst[0].mid;

+		dst[0].mid = 0;		/* simplify loops */

+		if (parent->mt_parent) {

+			len = x + src[0].mid;

+			y = mdb_mid2l_search(src, dst[x].mid + 1) - 1;

+			for (i = x; y && i; y--) {

+				pgno_t yp = src[y].mid;

+				while (yp < dst[i].mid)

+					i--;

+				if (yp == dst[i].mid) {

+					i--;

+					len--;

+				}

+			}

+		} else { /* Simplify the above for single-ancestor case */

+			len = MDB_IDL_UM_MAX - txn->mt_dirty_room;

+		}

+		/* Merge our dirty list with parent's */

+		y = src[0].mid;

+		for (i = len; y; dst[i--] = src[y--]) {

+			pgno_t yp = src[y].mid;

+			while (yp < dst[x].mid)

+				dst[i--] = dst[x--];

+			if (yp == dst[x].mid)

+				free(dst[x--].mptr);

+		}

+		mdb_tassert(txn, i == x);

+		dst[0].mid = len;

+		free(txn->mt_u.dirty_list);

+		parent->mt_dirty_room = txn->mt_dirty_room;

+		if (txn->mt_spill_pgs) {

+			if (parent->mt_spill_pgs) {

+				/* TODO: Prevent failure here, so parent does not fail */

+				rc = mdb_midl_append_list(&parent->mt_spill_pgs, txn->mt_spill_pgs);

+				if (rc)

+					parent->mt_flags |= MDB_TXN_ERROR;

+				mdb_midl_free(txn->mt_spill_pgs);

+				mdb_midl_sort(parent->mt_spill_pgs);

+			} else {

+				parent->mt_spill_pgs = txn->mt_spill_pgs;

+			}

+		}

+

+		/* Append our loose page list to parent's */

+		for (lp = &parent->mt_loose_pgs; *lp; lp = &NEXT_LOOSE_PAGE(*lp))

+			;

+		*lp = txn->mt_loose_pgs;

+		parent->mt_loose_count += txn->mt_loose_count;

+

+		parent->mt_child = NULL;

+		mdb_midl_free(((MDB_ntxn *)txn)->mnt_pgstate.mf_pghead);

+		free(txn);

+		return rc;

+	}

+

+	if (txn != env->me_txn) {

+		DPUTS("attempt to commit unknown transaction");

+		rc = EINVAL;

+		goto fail;

+	}

+

+	mdb_cursors_close(txn, 0);

+

+	if (!txn->mt_u.dirty_list[0].mid &&

+		!(txn->mt_flags & (MDB_TXN_DIRTY|MDB_TXN_SPILLS)))

+		goto done;

+

+	DPRINTF(("committing txn %"Y"u %p on mdbenv %p, root page %"Y"u",

+	    txn->mt_txnid, (void*)txn, (void*)env, txn->mt_dbs[MAIN_DBI].md_root));

+

+	/* Update DB root pointers */

+	if (txn->mt_numdbs > CORE_DBS) {

+		MDB_cursor mc;

+		MDB_dbi i;

+		MDB_val data;

+		data.mv_size = sizeof(MDB_db);

+

+		mdb_cursor_init(&mc, txn, MAIN_DBI, NULL);

+		for (i = CORE_DBS; i < txn->mt_numdbs; i++) {

+			if (txn->mt_dbflags[i] & DB_DIRTY) {

+				if (TXN_DBI_CHANGED(txn, i)) {

+					rc = MDB_BAD_DBI;

+					goto fail;

+				}

+				data.mv_data = &txn->mt_dbs[i];

+				rc = mdb_cursor_put(&mc, &txn->mt_dbxs[i].md_name, &data,

+					F_SUBDATA);

+				if (rc)

+					goto fail;

+			}

+		}

+	}

+

+	rc = mdb_freelist_save(txn);

+	if (rc)

+		goto fail;

+

+	mdb_midl_free(env->me_pghead);

+	env->me_pghead = NULL;

+	mdb_midl_shrink(&txn->mt_free_pgs);

+

+#if (MDB_DEBUG) > 2

+	mdb_audit(txn);

+#endif

+

+	if ((rc = mdb_page_flush(txn, 0)))

+		goto fail;

+	if (!F_ISSET(txn->mt_flags, MDB_TXN_NOSYNC) &&

+		(rc = mdb_env_sync0(env, 0, txn->mt_next_pgno)))

+		goto fail;

+	if ((rc = mdb_env_write_meta(txn)))

+		goto fail;

+	end_mode = MDB_END_COMMITTED|MDB_END_UPDATE;

+

+done:

+	mdb_txn_end(txn, end_mode);

+	return MDB_SUCCESS;

+

+fail:

+	mdb_txn_abort(txn);

+	return rc;

+}

+

+/** Read the environment parameters of a DB environment before

+ * mapping it into memory.

+ * @param[in] env the environment handle

+ * @param[out] meta address of where to store the meta information

+ * @return 0 on success, non-zero on failure.

+ */

+static int ESECT

+mdb_env_read_header(MDB_env *env, MDB_meta *meta)

+{

+	MDB_metabuf	pbuf;

+	MDB_page	*p;

+	MDB_meta	*m;

+	int			i, rc, off;

+	enum { Size = sizeof(pbuf) };

+

+	/* We don't know the page size yet, so use a minimum value.

+	 * Read both meta pages so we can use the latest one.

+	 */

+

+	for (i=off=0; i<NUM_METAS; i++, off += meta->mm_psize) {

+#ifdef _WIN32

+		DWORD len;

+		OVERLAPPED ov;

+		memset(&ov, 0, sizeof(ov));

+		ov.Offset = off;

+		rc = ReadFile(env->me_fd, &pbuf, Size, &len, &ov) ? (int)len : -1;

+		if (rc == -1 && ErrCode() == ERROR_HANDLE_EOF)

+			rc = 0;

+#else

+		rc = pread(env->me_fd, &pbuf, Size, off);

+#endif

+		if (rc != Size) {

+			if (rc == 0 && off == 0)

+				return ENOENT;

+			rc = rc < 0 ? (int) ErrCode() : MDB_INVALID;

+			DPRINTF(("read: %s", mdb_strerror(rc)));

+			return rc;

+		}

+

+		p = (MDB_page *)&pbuf;

+

+		if (!F_ISSET(p->mp_flags, P_META)) {

+			DPRINTF(("page %"Y"u not a meta page", p->mp_pgno));

+			return MDB_INVALID;

+		}

+

+		m = METADATA(p);

+		if (m->mm_magic != MDB_MAGIC) {

+			DPUTS("meta has invalid magic");

+			return MDB_INVALID;

+		}

+

+		if (m->mm_version != MDB_DATA_VERSION) {

+			DPRINTF(("database is version %u, expected version %u",

+				m->mm_version, MDB_DATA_VERSION));

+			return MDB_VERSION_MISMATCH;

+		}

+

+		if (off == 0 || m->mm_txnid > meta->mm_txnid)

+			*meta = *m;

+	}

+	return 0;

+}

+

+/** Fill in most of the zeroed #MDB_meta for an empty database environment */

+static void ESECT

+mdb_env_init_meta0(MDB_env *env, MDB_meta *meta)

+{

+	meta->mm_magic = MDB_MAGIC;

+	meta->mm_version = MDB_DATA_VERSION;

+	meta->mm_mapsize = env->me_mapsize;

+	meta->mm_psize = env->me_psize;

+	meta->mm_last_pg = NUM_METAS-1;

+	meta->mm_flags = env->me_flags & 0xffff;

+	meta->mm_flags |= MDB_INTEGERKEY; /* this is mm_dbs[FREE_DBI].md_flags */

+	meta->mm_dbs[FREE_DBI].md_root = P_INVALID;

+	meta->mm_dbs[MAIN_DBI].md_root = P_INVALID;

+}

+

+/** Write the environment parameters of a freshly created DB environment.

+ * @param[in] env the environment handle

+ * @param[in] meta the #MDB_meta to write

+ * @return 0 on success, non-zero on failure.

+ */

+static int ESECT

+mdb_env_init_meta(MDB_env *env, MDB_meta *meta)

+{

+	MDB_page *p, *q;

+	int rc;

+	unsigned int	 psize;

+#ifdef _WIN32

+	DWORD len;

+	OVERLAPPED ov;

+	memset(&ov, 0, sizeof(ov));

+#define DO_PWRITE(rc, fd, ptr, size, len, pos)	do { \

+	ov.Offset = pos;	\

+	rc = WriteFile(fd, ptr, size, &len, &ov);	} while(0)

+#else

+	int len;

+#define DO_PWRITE(rc, fd, ptr, size, len, pos)	do { \

+	len = pwrite(fd, ptr, size, pos);	\

+	if (len == -1 && ErrCode() == EINTR) continue; \

+	rc = (len >= 0); break; } while(1)

+#endif

+

+	DPUTS("writing new meta page");

+

+	psize = env->me_psize;

+

+	p = calloc(NUM_METAS, psize);

+	if (!p)

+		return ENOMEM;

+	p->mp_pgno = 0;

+	p->mp_flags = P_META;

+	*(MDB_meta *)METADATA(p) = *meta;

+

+	q = (MDB_page *)((char *)p + psize);

+	q->mp_pgno = 1;

+	q->mp_flags = P_META;

+	*(MDB_meta *)METADATA(q) = *meta;

+

+	DO_PWRITE(rc, env->me_fd, p, psize * NUM_METAS, len, 0);

+	if (!rc)

+		rc = ErrCode();

+	else if ((unsigned) len == psize * NUM_METAS)

+		rc = MDB_SUCCESS;

+	else

+		rc = ENOSPC;

+	free(p);

+	return rc;

+}

+

+/** Update the environment info to commit a transaction.

+ * @param[in] txn the transaction that's being committed

+ * @return 0 on success, non-zero on failure.

+ */

+static int

+mdb_env_write_meta(MDB_txn *txn)

+{

+	MDB_env *env;

+	MDB_meta	meta, metab, *mp;

+	unsigned flags;

+	mdb_size_t mapsize;

+	off_t off;

+	int rc, len, toggle;

+	char *ptr;

+	HANDLE mfd;

+#ifdef _WIN32

+	OVERLAPPED ov;

+#else

+	int r2;

+#endif

+

+	toggle = txn->mt_txnid & 1;

+	DPRINTF(("writing meta page %d for root page %"Y"u",

+		toggle, txn->mt_dbs[MAIN_DBI].md_root));

+

+	env = txn->mt_env;

+	flags = txn->mt_flags | env->me_flags;

+	mp = env->me_metas[toggle];

+	mapsize = env->me_metas[toggle ^ 1]->mm_mapsize;

+	/* Persist any increases of mapsize config */

+	if (mapsize < env->me_mapsize)

+		mapsize = env->me_mapsize;

+

+	if (flags & MDB_WRITEMAP) {

+		mp->mm_mapsize = mapsize;

+		mp->mm_dbs[FREE_DBI] = txn->mt_dbs[FREE_DBI];

+		mp->mm_dbs[MAIN_DBI] = txn->mt_dbs[MAIN_DBI];

+		mp->mm_last_pg = txn->mt_next_pgno - 1;

+#if (__GNUC__ * 100 + __GNUC_MINOR__ >= 404) && /* TODO: portability */	\

+	!(defined(__i386__) || defined(__x86_64__))

+		/* LY: issue a memory barrier, if not x86. ITS#7969 */

+		__sync_synchronize();

+#endif

+		mp->mm_txnid = txn->mt_txnid;

+		if (!(flags & (MDB_NOMETASYNC|MDB_NOSYNC))) {

+			unsigned meta_size = env->me_psize;

+			rc = (env->me_flags & MDB_MAPASYNC) ? MS_ASYNC : MS_SYNC;

+			ptr = (char *)mp - PAGEHDRSZ;

+#ifndef _WIN32	/* POSIX msync() requires ptr = start of OS page */

+			r2 = (ptr - env->me_map) & (env->me_os_psize - 1);

+			ptr -= r2;

+			meta_size += r2;

+#endif

+			if (MDB_MSYNC(ptr, meta_size, rc)) {

+				rc = ErrCode();

+				goto fail;

+			}

+		}

+		goto done;

+	}

+	metab.mm_txnid = mp->mm_txnid;

+	metab.mm_last_pg = mp->mm_last_pg;

+

+	meta.mm_mapsize = mapsize;

+	meta.mm_dbs[FREE_DBI] = txn->mt_dbs[FREE_DBI];

+	meta.mm_dbs[MAIN_DBI] = txn->mt_dbs[MAIN_DBI];

+	meta.mm_last_pg = txn->mt_next_pgno - 1;

+	meta.mm_txnid = txn->mt_txnid;

+

+	off = offsetof(MDB_meta, mm_mapsize);

+	ptr = (char *)&meta + off;

+	len = sizeof(MDB_meta) - off;

+	off += (char *)mp - env->me_map;

+

+	/* Write to the SYNC fd */

+	mfd = (flags & (MDB_NOSYNC|MDB_NOMETASYNC)) ? env->me_fd : env->me_mfd;

+#ifdef _WIN32

+	{

+		memset(&ov, 0, sizeof(ov));

+		ov.Offset = off;

+		if (!WriteFile(mfd, ptr, len, (DWORD *)&rc, &ov))

+			rc = -1;

+	}

+#else

+retry_write:

+	rc = pwrite(mfd, ptr, len, off);

+#endif

+	if (rc != len) {

+		rc = rc < 0 ? ErrCode() : EIO;

+#ifndef _WIN32

+		if (rc == EINTR)

+			goto retry_write;

+#endif

+		DPUTS("write failed, disk error?");

+		/* On a failure, the pagecache still contains the new data.

+		 * Write some old data back, to prevent it from being used.

+		 * Use the non-SYNC fd; we know it will fail anyway.

+		 */

+		meta.mm_last_pg = metab.mm_last_pg;

+		meta.mm_txnid = metab.mm_txnid;

+#ifdef _WIN32

+		memset(&ov, 0, sizeof(ov));

+		ov.Offset = off;

+		WriteFile(env->me_fd, ptr, len, NULL, &ov);

+#else

+		r2 = pwrite(env->me_fd, ptr, len, off);

+		(void)r2;	/* Silence warnings. We don't care about pwrite's return value */

+#endif

+fail:

+		env->me_flags |= MDB_FATAL_ERROR;

+		return rc;

+	}

+	/* MIPS has cache coherency issues, this is a no-op everywhere else */

+	CACHEFLUSH(env->me_map + off, len, DCACHE);

+done:

+	/* Memory ordering issues are irrelevant; since the entire writer

+	 * is wrapped by wmutex, all of these changes will become visible

+	 * after the wmutex is unlocked. Since the DB is multi-version,

+	 * readers will get consistent data regardless of how fresh or

+	 * how stale their view of these values is.

+	 */

+	if (env->me_txns)

+		env->me_txns->mti_txnid = txn->mt_txnid;

+

+	return MDB_SUCCESS;

+}

+

+/** Check both meta pages to see which one is newer.

+ * @param[in] env the environment handle

+ * @return newest #MDB_meta.

+ */

+static MDB_meta *

+mdb_env_pick_meta(const MDB_env *env)

+{

+	MDB_meta *const *metas = env->me_metas;

+	return metas[ metas[0]->mm_txnid < metas[1]->mm_txnid ];

+}

+

+int ESECT

+mdb_env_create(MDB_env **env)

+{

+	MDB_env *e;

+

+	e = calloc(1, sizeof(MDB_env));

+	if (!e)

+		return ENOMEM;

+

+	e->me_maxreaders = DEFAULT_READERS;

+	e->me_maxdbs = e->me_numdbs = CORE_DBS;

+	e->me_fd = INVALID_HANDLE_VALUE;

+	e->me_lfd = INVALID_HANDLE_VALUE;

+	e->me_mfd = INVALID_HANDLE_VALUE;

+#ifdef MDB_USE_POSIX_SEM

+	e->me_rmutex = SEM_FAILED;

+	e->me_wmutex = SEM_FAILED;

+#elif defined MDB_USE_SYSV_SEM

+	e->me_rmutex->semid = -1;

+	e->me_wmutex->semid = -1;

+#endif

+	e->me_pid = getpid();

+	GET_PAGESIZE(e->me_os_psize);

+	VGMEMP_CREATE(e,0,0);

+	*env = e;

+	return MDB_SUCCESS;

+}

+

+#ifdef _WIN32

+/** @brief Map a result from an NTAPI call to WIN32. */

+static DWORD

+mdb_nt2win32(NTSTATUS st)

+{

+	OVERLAPPED o = {0};

+	DWORD br;

+	o.Internal = st;

+	GetOverlappedResult(NULL, &o, &br, FALSE);

+	return GetLastError();

+}

+#endif

+

+static int ESECT

+mdb_env_map(MDB_env *env, void *addr)

+{

+	MDB_page *p;

+	unsigned int flags = env->me_flags;

+#ifdef _WIN32

+	int rc;

+	int access = SECTION_MAP_READ;

+	HANDLE mh;

+	void *map;

+	SIZE_T msize;

+	ULONG pageprot = PAGE_READONLY, secprot, alloctype;

+

+	if (flags & MDB_WRITEMAP) {

+		access |= SECTION_MAP_WRITE;

+		pageprot = PAGE_READWRITE;

+	}

+	if (flags & MDB_RDONLY) {

+		secprot = PAGE_READONLY;

+		msize = 0;

+		alloctype = 0;

+	} else {

+		secprot = PAGE_READWRITE;

+		msize = env->me_mapsize;

+		alloctype = MEM_RESERVE;

+	}

+

+	rc = NtCreateSection(&mh, access, NULL, NULL, secprot, SEC_RESERVE, env->me_fd);

+	if (rc)

+		return mdb_nt2win32(rc);

+	map = addr;

+#ifdef MDB_VL32

+	msize = NUM_METAS * env->me_psize;

+#endif

+	rc = NtMapViewOfSection(mh, GetCurrentProcess(), &map, 0, 0, NULL, &msize, ViewUnmap, alloctype, pageprot);

+#ifdef MDB_VL32

+	env->me_fmh = mh;

+#else

+	NtClose(mh);

+#endif

+	if (rc)

+		return mdb_nt2win32(rc);

+	env->me_map = map;

+#else

+#ifdef MDB_VL32

+	(void) flags;

+	env->me_map = mmap(addr, NUM_METAS * env->me_psize, PROT_READ, MAP_SHARED,

+		env->me_fd, 0);

+	if (env->me_map == MAP_FAILED) {

+		env->me_map = NULL;

+		return ErrCode();

+	}

+#else

+	int prot = PROT_READ;

+	if (flags & MDB_WRITEMAP) {

+		prot |= PROT_WRITE;

+		if (ftruncate(env->me_fd, env->me_mapsize) < 0)

+			return ErrCode();

+	}

+	env->me_map = mmap(addr, env->me_mapsize, prot, MAP_SHARED,

+		env->me_fd, 0);

+	if (env->me_map == MAP_FAILED) {

+		env->me_map = NULL;

+		return ErrCode();

+	}

+

+	if (flags & MDB_NORDAHEAD) {

+		/* Turn off readahead. It's harmful when the DB is larger than RAM. */

+#ifdef MADV_RANDOM

+		madvise(env->me_map, env->me_mapsize, MADV_RANDOM);

+#else

+#ifdef POSIX_MADV_RANDOM

+		posix_madvise(env->me_map, env->me_mapsize, POSIX_MADV_RANDOM);

+#endif /* POSIX_MADV_RANDOM */

+#endif /* MADV_RANDOM */

+	}

+#endif /* _WIN32 */

+

+	/* Can happen because the address argument to mmap() is just a

+	 * hint.  mmap() can pick another, e.g. if the range is in use.

+	 * The MAP_FIXED flag would prevent that, but then mmap could

+	 * instead unmap existing pages to make room for the new map.

+	 */

+	if (addr && env->me_map != addr)

+		return EBUSY;	/* TODO: Make a new MDB_* error code? */

+#endif

+

+	p = (MDB_page *)env->me_map;

+	env->me_metas[0] = METADATA(p);

+	env->me_metas[1] = (MDB_meta *)((char *)env->me_metas[0] + env->me_psize);

+

+	return MDB_SUCCESS;

+}

+

+int ESECT

+mdb_env_set_mapsize(MDB_env *env, mdb_size_t size)

+{

+	/* If env is already open, caller is responsible for making

+	 * sure there are no active txns.

+	 */

+	if (env->me_map) {

+		MDB_meta *meta;

+#ifndef MDB_VL32

+		void *old;

+		int rc;

+#endif

+		if (env->me_txn)

+			return EINVAL;

+		meta = mdb_env_pick_meta(env);

+		if (!size)

+			size = meta->mm_mapsize;

+		{

+			/* Silently round up to minimum if the size is too small */

+			mdb_size_t minsize = (meta->mm_last_pg + 1) * env->me_psize;

+			if (size < minsize)

+				size = minsize;

+		}

+#ifndef MDB_VL32

+		/* For MDB_VL32 this bit is a noop since we dynamically remap

+		 * chunks of the DB anyway.

+		 */

+		munmap(env->me_map, env->me_mapsize);

+		env->me_mapsize = size;

+		old = (env->me_flags & MDB_FIXEDMAP) ? env->me_map : NULL;

+		rc = mdb_env_map(env, old);

+		if (rc)

+			return rc;

+#endif /* !MDB_VL32 */

+	}

+	env->me_mapsize = size;

+	if (env->me_psize)

+		env->me_maxpg = env->me_mapsize / env->me_psize;

+	return MDB_SUCCESS;

+}

+

+int ESECT

+mdb_env_set_maxdbs(MDB_env *env, MDB_dbi dbs)

+{

+	if (env->me_map)

+		return EINVAL;

+	env->me_maxdbs = dbs + CORE_DBS;

+	return MDB_SUCCESS;

+}

+

+int ESECT

+mdb_env_set_maxreaders(MDB_env *env, unsigned int readers)

+{

+	if (env->me_map || readers < 1)

+		return EINVAL;

+	env->me_maxreaders = readers;

+	return MDB_SUCCESS;

+}

+

+int ESECT

+mdb_env_get_maxreaders(MDB_env *env, unsigned int *readers)

+{

+	if (!env || !readers)

+		return EINVAL;

+	*readers = env->me_maxreaders;

+	return MDB_SUCCESS;

+}

+

+static int ESECT

+mdb_fsize(HANDLE fd, mdb_size_t *size)

+{

+#ifdef _WIN32

+	LARGE_INTEGER fsize;

+

+	if (!GetFileSizeEx(fd, &fsize))

+		return ErrCode();

+

+	*size = fsize.QuadPart;

+#else

+	struct stat st;

+

+	if (fstat(fd, &st))

+		return ErrCode();

+

+	*size = st.st_size;

+#endif

+	return MDB_SUCCESS;

+}

+

+#ifdef BROKEN_FDATASYNC

+#include <sys/utsname.h>

+#include <sys/vfs.h>

+#endif

+

+/** Further setup required for opening an LMDB environment

+ */

+static int ESECT

+mdb_env_open2(MDB_env *env)

+{

+	unsigned int flags = env->me_flags;

+	int i, newenv = 0, rc;

+	MDB_meta meta;

+

+#ifdef _WIN32

+	/* See if we should use QueryLimited */

+	rc = GetVersion();

+	if ((rc & 0xff) > 5)

+		env->me_pidquery = MDB_PROCESS_QUERY_LIMITED_INFORMATION;

+	else

+		env->me_pidquery = PROCESS_QUERY_INFORMATION;

+#endif /* _WIN32 */

+

+#ifdef BROKEN_FDATASYNC

+	/* ext3/ext4 fdatasync is broken on some older Linux kernels.

+	 * https://lkml.org/lkml/2012/9/3/83

+	 * Kernels after 3.6-rc6 are known good.

+	 * https://lkml.org/lkml/2012/9/10/556

+	 * See if the DB is on ext3/ext4, then check for new enough kernel

+	 * Kernels 2.6.32.60, 2.6.34.15, 3.2.30, and 3.5.4 are also known

+	 * to be patched.

+	 */

+	{

+		struct statfs st;

+		fstatfs(env->me_fd, &st);

+		while (st.f_type == 0xEF53) {

+			struct utsname uts;

+			int i;

+			uname(&uts);

+			if (uts.release[0] < '3') {

+				if (!strncmp(uts.release, "2.6.32.", 7)) {

+					i = atoi(uts.release+7);

+					if (i >= 60)

+						break;	/* 2.6.32.60 and newer is OK */

+				} else if (!strncmp(uts.release, "2.6.34.", 7)) {

+					i = atoi(uts.release+7);

+					if (i >= 15)

+						break;	/* 2.6.34.15 and newer is OK */

+				}

+			} else if (uts.release[0] == '3') {

+				i = atoi(uts.release+2);

+				if (i > 5)

+					break;	/* 3.6 and newer is OK */

+				if (i == 5) {

+					i = atoi(uts.release+4);

+					if (i >= 4)

+						break;	/* 3.5.4 and newer is OK */

+				} else if (i == 2) {

+					i = atoi(uts.release+4);

+					if (i >= 30)

+						break;	/* 3.2.30 and newer is OK */

+				}

+			} else {	/* 4.x and newer is OK */

+				break;

+			}

+			env->me_flags |= MDB_FSYNCONLY;

+			break;

+		}

+	}

+#endif

+

+	if ((i = mdb_env_read_header(env, &meta)) != 0) {

+		if (i != ENOENT)

+			return i;

+		DPUTS("new mdbenv");

+		newenv = 1;

+		env->me_psize = env->me_os_psize;

+		if (env->me_psize > MAX_PAGESIZE)

+			env->me_psize = MAX_PAGESIZE;

+		memset(&meta, 0, sizeof(meta));

+		mdb_env_init_meta0(env, &meta);

+		meta.mm_mapsize = DEFAULT_MAPSIZE;

+	} else {

+		env->me_psize = meta.mm_psize;

+	}

+

+	/* Was a mapsize configured? */

+	if (!env->me_mapsize) {

+		env->me_mapsize = meta.mm_mapsize;

+	}

+	{

+		/* Make sure mapsize >= committed data size.  Even when using

+		 * mm_mapsize, which could be broken in old files (ITS#7789).

+		 */

+		mdb_size_t minsize = (meta.mm_last_pg + 1) * meta.mm_psize;

+		if (env->me_mapsize < minsize)

+			env->me_mapsize = minsize;

+	}

+	meta.mm_mapsize = env->me_mapsize;

+

+	if (newenv && !(flags & MDB_FIXEDMAP)) {

+		/* mdb_env_map() may grow the datafile.  Write the metapages

+		 * first, so the file will be valid if initialization fails.

+		 * Except with FIXEDMAP, since we do not yet know mm_address.

+		 * We could fill in mm_address later, but then a different

+		 * program might end up doing that - one with a memory layout

+		 * and map address which does not suit the main program.

+		 */

+		rc = mdb_env_init_meta(env, &meta);

+		if (rc)

+			return rc;

+		newenv = 0;

+	}

+#ifdef _WIN32

+	/* For FIXEDMAP, make sure the file is non-empty before we attempt to map it */

+	if (newenv) {

+		char dummy = 0;

+		DWORD len;

+		rc = WriteFile(env->me_fd, &dummy, 1, &len, NULL);

+		if (!rc) {

+			rc = ErrCode();

+			return rc;

+		}

+	}

+#endif

+

+	rc = mdb_env_map(env, (flags & MDB_FIXEDMAP) ? meta.mm_address : NULL);

+	if (rc)

+		return rc;

+

+	if (newenv) {

+		if (flags & MDB_FIXEDMAP)

+			meta.mm_address = env->me_map;

+		i = mdb_env_init_meta(env, &meta);

+		if (i != MDB_SUCCESS) {

+			return i;

+		}

+	}

+

+	env->me_maxfree_1pg = (env->me_psize - PAGEHDRSZ) / sizeof(pgno_t) - 1;

+	env->me_nodemax = (((env->me_psize - PAGEHDRSZ) / MDB_MINKEYS) & -2)

+		- sizeof(indx_t);

+#if !(MDB_MAXKEYSIZE)

+	env->me_maxkey = env->me_nodemax - (NODESIZE + sizeof(MDB_db));

+#endif

+	env->me_maxpg = env->me_mapsize / env->me_psize;

+

+#if MDB_DEBUG

+	{

+		MDB_meta *meta = mdb_env_pick_meta(env);

+		MDB_db *db = &meta->mm_dbs[MAIN_DBI];

+

+		DPRINTF(("opened database version %u, pagesize %u",

+			meta->mm_version, env->me_psize));

+		DPRINTF(("using meta page %d",    (int) (meta->mm_txnid & 1)));

+		DPRINTF(("depth: %u",             db->md_depth));

+		DPRINTF(("entries: %"Y"u",        db->md_entries));

+		DPRINTF(("branch pages: %"Y"u",   db->md_branch_pages));

+		DPRINTF(("leaf pages: %"Y"u",     db->md_leaf_pages));

+		DPRINTF(("overflow pages: %"Y"u", db->md_overflow_pages));

+		DPRINTF(("root: %"Y"u",           db->md_root));

+	}

+#endif

+

+	return MDB_SUCCESS;

+}

+

+

+/** Release a reader thread's slot in the reader lock table.

+ *	This function is called automatically when a thread exits.

+ * @param[in] ptr This points to the slot in the reader lock table.

+ */

+static void

+mdb_env_reader_dest(void *ptr)

+{

+	MDB_reader *reader = ptr;

+

+	reader->mr_pid = 0;

+}

+

+#ifdef _WIN32

+/** Junk for arranging thread-specific callbacks on Windows. This is

+ *	necessarily platform and compiler-specific. Windows supports up

+ *	to 1088 keys. Let's assume nobody opens more than 64 environments

+ *	in a single process, for now. They can override this if needed.

+ */

+#ifndef MAX_TLS_KEYS

+#define MAX_TLS_KEYS	64

+#endif

+static pthread_key_t mdb_tls_keys[MAX_TLS_KEYS];

+static int mdb_tls_nkeys;

+

+static void NTAPI mdb_tls_callback(PVOID module, DWORD reason, PVOID ptr)

+{

+	int i;

+	switch(reason) {

+	case DLL_PROCESS_ATTACH: break;

+	case DLL_THREAD_ATTACH: break;

+	case DLL_THREAD_DETACH:

+		for (i=0; i<mdb_tls_nkeys; i++) {

+			MDB_reader *r = pthread_getspecific(mdb_tls_keys[i]);

+			if (r) {

+				mdb_env_reader_dest(r);

+			}

+		}

+		break;

+	case DLL_PROCESS_DETACH: break;

+	}

+}

+#ifdef __GNUC__

+#ifdef _WIN64

+const PIMAGE_TLS_CALLBACK mdb_tls_cbp __attribute__((section (".CRT$XLB"))) = mdb_tls_callback;

+#else

+PIMAGE_TLS_CALLBACK mdb_tls_cbp __attribute__((section (".CRT$XLB"))) = mdb_tls_callback;

+#endif

+#else

+#ifdef _WIN64

+/* Force some symbol references.

+ *	_tls_used forces the linker to create the TLS directory if not already done

+ *	mdb_tls_cbp prevents whole-program-optimizer from dropping the symbol.

+ */

+#pragma comment(linker, "/INCLUDE:_tls_used")

+#pragma comment(linker, "/INCLUDE:mdb_tls_cbp")

+#pragma const_seg(".CRT$XLB")

+extern const PIMAGE_TLS_CALLBACK mdb_tls_cbp;

+const PIMAGE_TLS_CALLBACK mdb_tls_cbp = mdb_tls_callback;

+#pragma const_seg()

+#else	/* _WIN32 */

+#pragma comment(linker, "/INCLUDE:__tls_used")

+#pragma comment(linker, "/INCLUDE:_mdb_tls_cbp")

+#pragma data_seg(".CRT$XLB")

+PIMAGE_TLS_CALLBACK mdb_tls_cbp = mdb_tls_callback;

+#pragma data_seg()

+#endif	/* WIN 32/64 */

+#endif	/* !__GNUC__ */

+#endif

+

+/** Downgrade the exclusive lock on the region back to shared */

+static int ESECT

+mdb_env_share_locks(MDB_env *env, int *excl)

+{

+	int rc = 0;

+	MDB_meta *meta = mdb_env_pick_meta(env);

+

+	env->me_txns->mti_txnid = meta->mm_txnid;

+

+#ifdef _WIN32

+	{

+		OVERLAPPED ov;

+		/* First acquire a shared lock. The Unlock will

+		 * then release the existing exclusive lock.

+		 */

+		memset(&ov, 0, sizeof(ov));

+		if (!LockFileEx(env->me_lfd, 0, 0, 1, 0, &ov)) {

+			rc = ErrCode();

+		} else {

+			UnlockFile(env->me_lfd, 0, 0, 1, 0);

+			*excl = 0;

+		}

+	}

+#else

+	{

+		struct flock lock_info;

+		/* The shared lock replaces the existing lock */

+		memset((void *)&lock_info, 0, sizeof(lock_info));

+		lock_info.l_type = F_RDLCK;

+		lock_info.l_whence = SEEK_SET;

+		lock_info.l_start = 0;

+		lock_info.l_len = 1;

+		while ((rc = fcntl(env->me_lfd, F_SETLK, &lock_info)) &&

+				(rc = ErrCode()) == EINTR) ;

+		*excl = rc ? -1 : 0;	/* error may mean we lost the lock */

+	}

+#endif

+

+	return rc;

+}

+

+/** Try to get exclusive lock, otherwise shared.

+ *	Maintain *excl = -1: no/unknown lock, 0: shared, 1: exclusive.

+ */

+static int ESECT

+mdb_env_excl_lock(MDB_env *env, int *excl)

+{

+	int rc = 0;

+#ifdef _WIN32

+	if (LockFile(env->me_lfd, 0, 0, 1, 0)) {

+		*excl = 1;

+	} else {

+		OVERLAPPED ov;

+		memset(&ov, 0, sizeof(ov));

+		if (LockFileEx(env->me_lfd, 0, 0, 1, 0, &ov)) {

+			*excl = 0;

+		} else {

+			rc = ErrCode();

+		}

+	}

+#else

+	struct flock lock_info;

+	memset((void *)&lock_info, 0, sizeof(lock_info));

+	lock_info.l_type = F_WRLCK;

+	lock_info.l_whence = SEEK_SET;

+	lock_info.l_start = 0;

+	lock_info.l_len = 1;

+	while ((rc = fcntl(env->me_lfd, F_SETLK, &lock_info)) &&

+			(rc = ErrCode()) == EINTR) ;

+	if (!rc) {

+		*excl = 1;

+	} else

+# ifndef MDB_USE_POSIX_MUTEX

+	if (*excl < 0) /* always true when MDB_USE_POSIX_MUTEX */

+# endif

+	{

+		lock_info.l_type = F_RDLCK;

+		while ((rc = fcntl(env->me_lfd, F_SETLKW, &lock_info)) &&

+				(rc = ErrCode()) == EINTR) ;

+		if (rc == 0)

+			*excl = 0;

+	}

+#endif

+	return rc;

+}

+

+#ifdef MDB_USE_HASH

+/*

+ * hash_64 - 64 bit Fowler/Noll/Vo-0 FNV-1a hash code

+ *

+ * @(#) $Revision: 5.1 $

+ * @(#) $Id: hash_64a.c,v 5.1 2009/06/30 09:01:38 chongo Exp $

+ * @(#) $Source: /usr/local/src/cmd/fnv/RCS/hash_64a.c,v $

+ *

+ *	  http://www.isthe.com/chongo/tech/comp/fnv/index.html

+ *

+ ***

+ *

+ * Please do not copyright this code.  This code is in the public domain.

+ *

+ * LANDON CURT NOLL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,

+ * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO

+ * EVENT SHALL LANDON CURT NOLL BE LIABLE FOR ANY SPECIAL, INDIRECT OR

+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF

+ * USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR

+ * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR

+ * PERFORMANCE OF THIS SOFTWARE.

+ *

+ * By:

+ *	chongo <Landon Curt Noll> /\oo/\

+ *	  http://www.isthe.com/chongo/

+ *

+ * Share and Enjoy!	:-)

+ */

+

+typedef unsigned long long	mdb_hash_t;

+#define MDB_HASH_INIT ((mdb_hash_t)0xcbf29ce484222325ULL)

+

+/** perform a 64 bit Fowler/Noll/Vo FNV-1a hash on a buffer

+ * @param[in] val	value to hash

+ * @param[in] hval	initial value for hash

+ * @return 64 bit hash

+ *

+ * NOTE: To use the recommended 64 bit FNV-1a hash, use MDB_HASH_INIT as the

+ * 	 hval arg on the first call.

+ */

+static mdb_hash_t

+mdb_hash_val(MDB_val *val, mdb_hash_t hval)

+{

+	unsigned char *s = (unsigned char *)val->mv_data;	/* unsigned string */

+	unsigned char *end = s + val->mv_size;

+	/*

+	 * FNV-1a hash each octet of the string

+	 */

+	while (s < end) {

+		/* xor the bottom with the current octet */

+		hval ^= (mdb_hash_t)*s++;

+

+		/* multiply by the 64 bit FNV magic prime mod 2^64 */

+		hval += (hval << 1) + (hval << 4) + (hval << 5) +

+			(hval << 7) + (hval << 8) + (hval << 40);

+	}

+	/* return our new hash value */

+	return hval;

+}

+

+/** Hash the string and output the encoded hash.

+ * This uses modified RFC1924 Ascii85 encoding to accommodate systems with

+ * very short name limits. We don't care about the encoding being reversible,

+ * we just want to preserve as many bits of the input as possible in a

+ * small printable string.

+ * @param[in] str string to hash

+ * @param[out] encbuf an array of 11 chars to hold the hash

+ */

+static const char mdb_a85[]= "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz!#$%&()*+-;<=>?@^_`{|}~";

+

+static void ESECT

+mdb_pack85(unsigned long l, char *out)

+{

+	int i;

+

+	for (i=0; i<5; i++) {

+		*out++ = mdb_a85[l % 85];

+		l /= 85;

+	}

+}

+

+static void ESECT

+mdb_hash_enc(MDB_val *val, char *encbuf)

+{

+	mdb_hash_t h = mdb_hash_val(val, MDB_HASH_INIT);

+

+	mdb_pack85(h, encbuf);

+	mdb_pack85(h>>32, encbuf+5);

+	encbuf[10] = '\0';

+}

+#endif

+

+/** Open and/or initialize the lock region for the environment.

+ * @param[in] env The LMDB environment.

+ * @param[in] lpath The pathname of the file used for the lock region.

+ * @param[in] mode The Unix permissions for the file, if we create it.

+ * @param[in,out] excl In -1, out lock type: -1 none, 0 shared, 1 exclusive

+ * @return 0 on success, non-zero on failure.

+ */

+static int ESECT

+mdb_env_setup_locks(MDB_env *env, char *lpath, int mode, int *excl)

+{

+#ifdef _WIN32

+#	define MDB_ERRCODE_ROFS	ERROR_WRITE_PROTECT

+#else

+#	define MDB_ERRCODE_ROFS	EROFS

+#ifdef O_CLOEXEC	/* Linux: Open file and set FD_CLOEXEC atomically */

+#	define MDB_CLOEXEC		O_CLOEXEC

+#else

+	int fdflags;

+#	define MDB_CLOEXEC		0

+#endif

+#endif

+#ifdef MDB_USE_SYSV_SEM

+	int semid;

+	union semun semu;

+#endif

+	int rc;

+	off_t size, rsize;

+

+#ifdef _WIN32

+	wchar_t *wlpath;

+	rc = utf8_to_utf16(lpath, -1, &wlpath, NULL);

+	if (rc)

+		return rc;

+	env->me_lfd = CreateFileW(wlpath, GENERIC_READ|GENERIC_WRITE,

+		FILE_SHARE_READ|FILE_SHARE_WRITE, NULL, OPEN_ALWAYS,

+		FILE_ATTRIBUTE_NORMAL, NULL);

+	free(wlpath);

+#else

+	env->me_lfd = open(lpath, O_RDWR|O_CREAT|MDB_CLOEXEC, mode);

+#endif

+	if (env->me_lfd == INVALID_HANDLE_VALUE) {

+		rc = ErrCode();

+		if (rc == MDB_ERRCODE_ROFS && (env->me_flags & MDB_RDONLY)) {

+			return MDB_SUCCESS;

+		}

+		goto fail_errno;

+	}

+#if ! ((MDB_CLOEXEC) || defined(_WIN32))

+	/* Lose record locks when exec*() */

+	if ((fdflags = fcntl(env->me_lfd, F_GETFD) | FD_CLOEXEC) >= 0)

+			fcntl(env->me_lfd, F_SETFD, fdflags);

+#endif

+

+	if (!(env->me_flags & MDB_NOTLS)) {

+		rc = pthread_key_create(&env->me_txkey, mdb_env_reader_dest);

+		if (rc)

+			goto fail;

+		env->me_flags |= MDB_ENV_TXKEY;

+#ifdef _WIN32

+		/* Windows TLS callbacks need help finding their TLS info. */

+		if (mdb_tls_nkeys >= MAX_TLS_KEYS) {

+			rc = MDB_TLS_FULL;

+			goto fail;

+		}

+		mdb_tls_keys[mdb_tls_nkeys++] = env->me_txkey;

+#endif

+	}

+

+	/* Try to get exclusive lock. If we succeed, then

+	 * nobody is using the lock region and we should initialize it.

+	 */

+	if ((rc = mdb_env_excl_lock(env, excl))) goto fail;

+

+#ifdef _WIN32

+	size = GetFileSize(env->me_lfd, NULL);

+#else

+	size = lseek(env->me_lfd, 0, SEEK_END);

+	if (size == -1) goto fail_errno;

+#endif

+	rsize = (env->me_maxreaders-1) * sizeof(MDB_reader) + sizeof(MDB_txninfo);

+	if (size < rsize && *excl > 0) {

+#ifdef _WIN32

+		if (SetFilePointer(env->me_lfd, rsize, NULL, FILE_BEGIN) != (DWORD)rsize

+			|| !SetEndOfFile(env->me_lfd))

+			goto fail_errno;

+#else

+		if (ftruncate(env->me_lfd, rsize) != 0) goto fail_errno;

+#endif

+	} else {

+		rsize = size;

+		size = rsize - sizeof(MDB_txninfo);

+		env->me_maxreaders = size/sizeof(MDB_reader) + 1;

+	}

+	{

+#ifdef _WIN32

+		HANDLE mh;

+		mh = CreateFileMapping(env->me_lfd, NULL, PAGE_READWRITE,

+			0, 0, NULL);

+		if (!mh) goto fail_errno;

+		env->me_txns = MapViewOfFileEx(mh, FILE_MAP_WRITE, 0, 0, rsize, NULL);

+		CloseHandle(mh);

+		if (!env->me_txns) goto fail_errno;

+#else

+		void *m = mmap(NULL, rsize, PROT_READ|PROT_WRITE, MAP_SHARED,

+			env->me_lfd, 0);

+		if (m == MAP_FAILED) goto fail_errno;

+		env->me_txns = m;

+#endif

+	}

+	if (*excl > 0) {

+#ifdef _WIN32

+		BY_HANDLE_FILE_INFORMATION stbuf;

+		struct {

+			DWORD volume;

+			DWORD nhigh;

+			DWORD nlow;

+		} idbuf;

+		MDB_val val;

+		char encbuf[11];

+

+		if (!mdb_sec_inited) {

+			InitializeSecurityDescriptor(&mdb_null_sd,

+				SECURITY_DESCRIPTOR_REVISION);

+			SetSecurityDescriptorDacl(&mdb_null_sd, TRUE, 0, FALSE);

+			mdb_all_sa.nLength = sizeof(SECURITY_ATTRIBUTES);

+			mdb_all_sa.bInheritHandle = FALSE;

+			mdb_all_sa.lpSecurityDescriptor = &mdb_null_sd;

+			mdb_sec_inited = 1;

+		}

+		if (!GetFileInformationByHandle(env->me_lfd, &stbuf)) goto fail_errno;

+		idbuf.volume = stbuf.dwVolumeSerialNumber;

+		idbuf.nhigh  = stbuf.nFileIndexHigh;

+		idbuf.nlow   = stbuf.nFileIndexLow;

+		val.mv_data = &idbuf;

+		val.mv_size = sizeof(idbuf);

+		mdb_hash_enc(&val, encbuf);

+		sprintf(env->me_txns->mti_rmname, "Global\\MDBr%s", encbuf);

+		sprintf(env->me_txns->mti_wmname, "Global\\MDBw%s", encbuf);

+		env->me_rmutex = CreateMutexA(&mdb_all_sa, FALSE, env->me_txns->mti_rmname);

+		if (!env->me_rmutex) goto fail_errno;

+		env->me_wmutex = CreateMutexA(&mdb_all_sa, FALSE, env->me_txns->mti_wmname);

+		if (!env->me_wmutex) goto fail_errno;

+#elif defined(MDB_USE_POSIX_SEM)

+		struct stat stbuf;

+		struct {

+			dev_t dev;

+			ino_t ino;

+		} idbuf;

+		MDB_val val;

+		char encbuf[11];

+

+#if defined(__NetBSD__)

+#define	MDB_SHORT_SEMNAMES	1	/* limited to 14 chars */

+#endif

+		if (fstat(env->me_lfd, &stbuf)) goto fail_errno;

+		idbuf.dev = stbuf.st_dev;

+		idbuf.ino = stbuf.st_ino;

+		val.mv_data = &idbuf;

+		val.mv_size = sizeof(idbuf);

+		mdb_hash_enc(&val, encbuf);

+#ifdef MDB_SHORT_SEMNAMES

+		encbuf[9] = '\0';	/* drop name from 15 chars to 14 chars */

+#endif

+		sprintf(env->me_txns->mti_rmname, "/MDBr%s", encbuf);

+		sprintf(env->me_txns->mti_wmname, "/MDBw%s", encbuf);

+		/* Clean up after a previous run, if needed:  Try to

+		 * remove both semaphores before doing anything else.

+		 */

+		sem_unlink(env->me_txns->mti_rmname);

+		sem_unlink(env->me_txns->mti_wmname);

+		env->me_rmutex = sem_open(env->me_txns->mti_rmname,

+			O_CREAT|O_EXCL, mode, 1);

+		if (env->me_rmutex == SEM_FAILED) goto fail_errno;

+		env->me_wmutex = sem_open(env->me_txns->mti_wmname,

+			O_CREAT|O_EXCL, mode, 1);

+		if (env->me_wmutex == SEM_FAILED) goto fail_errno;

+#elif defined(MDB_USE_SYSV_SEM)

+		unsigned short vals[2] = {1, 1};

+		key_t key = ftok(lpath, 'M');

+		if (key == -1)

+			goto fail_errno;

+		semid = semget(key, 2, (mode & 0777) | IPC_CREAT);

+		if (semid < 0)

+			goto fail_errno;

+		semu.array = vals;

+		if (semctl(semid, 0, SETALL, semu) < 0)

+			goto fail_errno;

+		env->me_txns->mti_semid = semid;

+#else	/* MDB_USE_POSIX_MUTEX: */

+		pthread_mutexattr_t mattr;

+

+		if ((rc = pthread_mutexattr_init(&mattr))

+			|| (rc = pthread_mutexattr_setpshared(&mattr, PTHREAD_PROCESS_SHARED))

+#ifdef MDB_ROBUST_SUPPORTED

+			|| (rc = pthread_mutexattr_setrobust(&mattr, PTHREAD_MUTEX_ROBUST))

+#endif

+			|| (rc = pthread_mutex_init(env->me_txns->mti_rmutex, &mattr))

+			|| (rc = pthread_mutex_init(env->me_txns->mti_wmutex, &mattr)))

+			goto fail;

+		pthread_mutexattr_destroy(&mattr);

+#endif	/* _WIN32 || ... */

+

+		env->me_txns->mti_magic = MDB_MAGIC;

+		env->me_txns->mti_format = MDB_LOCK_FORMAT;

+		env->me_txns->mti_txnid = 0;

+		env->me_txns->mti_numreaders = 0;

+

+	} else {

+#ifdef MDB_USE_SYSV_SEM

+		struct semid_ds buf;

+#endif

+		if (env->me_txns->mti_magic != MDB_MAGIC) {

+			DPUTS("lock region has invalid magic");

+			rc = MDB_INVALID;

+			goto fail;

+		}

+		if (env->me_txns->mti_format != MDB_LOCK_FORMAT) {

+			DPRINTF(("lock region has format+version 0x%x, expected 0x%x",

+				env->me_txns->mti_format, MDB_LOCK_FORMAT));

+			rc = MDB_VERSION_MISMATCH;

+			goto fail;

+		}

+		rc = ErrCode();

+		if (rc && rc != EACCES && rc != EAGAIN) {

+			goto fail;

+		}

+#ifdef _WIN32

+		env->me_rmutex = OpenMutexA(SYNCHRONIZE, FALSE, env->me_txns->mti_rmname);

+		if (!env->me_rmutex) goto fail_errno;

+		env->me_wmutex = OpenMutexA(SYNCHRONIZE, FALSE, env->me_txns->mti_wmname);

+		if (!env->me_wmutex) goto fail_errno;

+#elif defined(MDB_USE_POSIX_SEM)

+		env->me_rmutex = sem_open(env->me_txns->mti_rmname, 0);

+		if (env->me_rmutex == SEM_FAILED) goto fail_errno;

+		env->me_wmutex = sem_open(env->me_txns->mti_wmname, 0);

+		if (env->me_wmutex == SEM_FAILED) goto fail_errno;

+#elif defined(MDB_USE_SYSV_SEM)

+		semid = env->me_txns->mti_semid;

+		semu.buf = &buf;

+		/* check for read access */

+		if (semctl(semid, 0, IPC_STAT, semu) < 0)

+			goto fail_errno;

+		/* check for write access */

+		if (semctl(semid, 0, IPC_SET, semu) < 0)

+			goto fail_errno;

+#endif

+	}

+#ifdef MDB_USE_SYSV_SEM

+	env->me_rmutex->semid = semid;

+	env->me_wmutex->semid = semid;

+	env->me_rmutex->semnum = 0;

+	env->me_wmutex->semnum = 1;

+	env->me_rmutex->locked = &env->me_txns->mti_rlocked;

+	env->me_wmutex->locked = &env->me_txns->mti_wlocked;

+#endif

+#ifdef MDB_VL32

+#ifdef _WIN32

+	env->me_rpmutex = CreateMutex(NULL, FALSE, NULL);

+#else

+	pthread_mutex_init(&env->me_rpmutex, NULL);

+#endif

+#endif

+

+	return MDB_SUCCESS;

+

+fail_errno:

+	rc = ErrCode();

+fail:

+	return rc;

+}

+

+	/** The name of the lock file in the DB environment */

+#define LOCKNAME	"/lock.mdb"

+	/** The name of the data file in the DB environment */

+#define DATANAME	"/data.mdb"

+	/** The suffix of the lock file when no subdir is used */

+#define LOCKSUFF	"-lock"

+	/** Only a subset of the @ref mdb_env flags can be changed

+	 *	at runtime. Changing other flags requires closing the

+	 *	environment and re-opening it with the new flags.

+	 */

+#define	CHANGEABLE	(MDB_NOSYNC|MDB_NOMETASYNC|MDB_MAPASYNC|MDB_NOMEMINIT)

+#define	CHANGELESS	(MDB_FIXEDMAP|MDB_NOSUBDIR|MDB_RDONLY| \

+	MDB_WRITEMAP|MDB_NOTLS|MDB_NOLOCK|MDB_NORDAHEAD)

+

+#if VALID_FLAGS & PERSISTENT_FLAGS & (CHANGEABLE|CHANGELESS)

+# error "Persistent DB flags & env flags overlap, but both go in mm_flags"

+#endif

+

+int ESECT

+mdb_env_open(MDB_env *env, const char *path, unsigned int flags, mdb_mode_t mode)

+{

+	int		oflags, rc, len, excl = -1;

+	char *lpath, *dpath;

+#ifdef _WIN32

+	wchar_t *wpath;

+#endif

+

+	if (env->me_fd!=INVALID_HANDLE_VALUE || (flags & ~(CHANGEABLE|CHANGELESS)))

+		return EINVAL;

+

+#ifdef MDB_VL32

+	if (flags & MDB_WRITEMAP) {

+		/* silently ignore WRITEMAP in 32 bit mode */

+		flags ^= MDB_WRITEMAP;

+	}

+	if (flags & MDB_FIXEDMAP) {

+		/* cannot support FIXEDMAP */

+		return EINVAL;

+	}

+#endif

+

+	len = strlen(path);

+	if (flags & MDB_NOSUBDIR) {

+		rc = len + sizeof(LOCKSUFF) + len + 1;

+	} else {

+		rc = len + sizeof(LOCKNAME) + len + sizeof(DATANAME);

+	}

+	lpath = malloc(rc);

+	if (!lpath)

+		return ENOMEM;

+	if (flags & MDB_NOSUBDIR) {

+		dpath = lpath + len + sizeof(LOCKSUFF);

+		sprintf(lpath, "%s" LOCKSUFF, path);

+		strcpy(dpath, path);

+	} else {

+		dpath = lpath + len + sizeof(LOCKNAME);

+		sprintf(lpath, "%s" LOCKNAME, path);

+		sprintf(dpath, "%s" DATANAME, path);

+	}

+

+	rc = MDB_SUCCESS;

+	flags |= env->me_flags;

+	if (flags & MDB_RDONLY) {

+		/* silently ignore WRITEMAP when we're only getting read access */

+		flags &= ~MDB_WRITEMAP;

+	} else {

+		if (!((env->me_free_pgs = mdb_midl_alloc(MDB_IDL_UM_MAX)) &&

+			  (env->me_dirty_list = calloc(MDB_IDL_UM_SIZE, sizeof(MDB_ID2)))))

+			rc = ENOMEM;

+	}

+#ifdef MDB_VL32

+	if (!rc) {

+		env->me_rpages = malloc(MDB_ERPAGE_SIZE * sizeof(MDB_ID3));

+		if (!env->me_rpages) {

+			rc = ENOMEM;

+			goto leave;

+		}

+		env->me_rpages[0].mid = 0;

+		env->me_rpcheck = MDB_ERPAGE_SIZE/2;

+	}

+#endif

+	env->me_flags = flags |= MDB_ENV_ACTIVE;

+	if (rc)

+		goto leave;

+

+	env->me_path = strdup(path);

+	env->me_dbxs = calloc(env->me_maxdbs, sizeof(MDB_dbx));

+	env->me_dbflags = calloc(env->me_maxdbs, sizeof(uint16_t));

+	env->me_dbiseqs = calloc(env->me_maxdbs, sizeof(unsigned int));

+	if (!(env->me_dbxs && env->me_path && env->me_dbflags && env->me_dbiseqs)) {

+		rc = ENOMEM;

+		goto leave;

+	}

+	env->me_dbxs[FREE_DBI].md_cmp = mdb_cmp_long; /* aligned MDB_INTEGERKEY */

+

+	/* For RDONLY, get lockfile after we know datafile exists */

+	if (!(flags & (MDB_RDONLY|MDB_NOLOCK))) {

+		rc = mdb_env_setup_locks(env, lpath, mode, &excl);

+		if (rc)

+			goto leave;

+	}

+

+#ifdef _WIN32

+	if (F_ISSET(flags, MDB_RDONLY)) {

+		oflags = GENERIC_READ;

+		len = OPEN_EXISTING;

+	} else {

+		oflags = GENERIC_READ|GENERIC_WRITE;

+		len = OPEN_ALWAYS;

+	}

+	mode = FILE_ATTRIBUTE_NORMAL;

+	rc = utf8_to_utf16(dpath, -1, &wpath, NULL);

+	if (rc)

+		goto leave;

+	env->me_fd = CreateFileW(wpath, oflags, FILE_SHARE_READ|FILE_SHARE_WRITE,

+		NULL, len, mode, NULL);

+	free(wpath);

+#else

+	if (F_ISSET(flags, MDB_RDONLY))

+		oflags = O_RDONLY;

+	else

+		oflags = O_RDWR | O_CREAT;

+

+	env->me_fd = open(dpath, oflags, mode);

+#endif

+	if (env->me_fd == INVALID_HANDLE_VALUE) {

+		rc = ErrCode();

+		goto leave;

+	}

+

+	if ((flags & (MDB_RDONLY|MDB_NOLOCK)) == MDB_RDONLY) {

+		rc = mdb_env_setup_locks(env, lpath, mode, &excl);

+		if (rc)

+			goto leave;

+	}

+

+	if ((rc = mdb_env_open2(env)) == MDB_SUCCESS) {

+		if (flags & (MDB_RDONLY|MDB_WRITEMAP)) {

+			env->me_mfd = env->me_fd;

+		} else {

+			/* Synchronous fd for meta writes. Needed even with

+			 * MDB_NOSYNC/MDB_NOMETASYNC, in case these get reset.

+			 */

+#ifdef _WIN32

+			len = OPEN_EXISTING;

+			rc = utf8_to_utf16(dpath, -1, &wpath, NULL);

+			if (rc)

+				goto leave;

+			env->me_mfd = CreateFileW(wpath, oflags,

+				FILE_SHARE_READ|FILE_SHARE_WRITE, NULL, len,

+				mode | FILE_FLAG_WRITE_THROUGH, NULL);

+			free(wpath);

+#else

+			oflags &= ~O_CREAT;

+			env->me_mfd = open(dpath, oflags | MDB_DSYNC, mode);

+#endif

+			if (env->me_mfd == INVALID_HANDLE_VALUE) {

+				rc = ErrCode();

+				goto leave;

+			}

+		}

+		DPRINTF(("opened dbenv %p", (void *) env));

+		if (excl > 0) {

+			rc = mdb_env_share_locks(env, &excl);

+			if (rc)

+				goto leave;

+		}

+		if (!(flags & MDB_RDONLY)) {

+			MDB_txn *txn;

+			int tsize = sizeof(MDB_txn), size = tsize + env->me_maxdbs *

+				(sizeof(MDB_db)+sizeof(MDB_cursor *)+sizeof(unsigned int)+1);

+			if ((env->me_pbuf = calloc(1, env->me_psize)) &&

+				(txn = calloc(1, size)))

+			{

+				txn->mt_dbs = (MDB_db *)((char *)txn + tsize);

+				txn->mt_cursors = (MDB_cursor **)(txn->mt_dbs + env->me_maxdbs);

+				txn->mt_dbiseqs = (unsigned int *)(txn->mt_cursors + env->me_maxdbs);

+				txn->mt_dbflags = (unsigned char *)(txn->mt_dbiseqs + env->me_maxdbs);

+				txn->mt_env = env;

+#ifdef MDB_VL32

+				txn->mt_rpages = malloc(MDB_TRPAGE_SIZE * sizeof(MDB_ID3));

+				if (!txn->mt_rpages) {

+					free(txn);

+					rc = ENOMEM;

+					goto leave;

+				}

+				txn->mt_rpages[0].mid = 0;

+				txn->mt_rpcheck = MDB_TRPAGE_SIZE/2;

+#endif

+				txn->mt_dbxs = env->me_dbxs;

+				txn->mt_flags = MDB_TXN_FINISHED;

+				env->me_txn0 = txn;

+			} else {

+				rc = ENOMEM;

+			}

+		}

+	}

+

+leave:

+	if (rc) {

+		mdb_env_close0(env, excl);

+	}

+	free(lpath);

+	return rc;

+}

+

+/** Destroy resources from mdb_env_open(), clear our readers & DBIs */

+static void ESECT

+mdb_env_close0(MDB_env *env, int excl)

+{

+	int i;

+

+	if (!(env->me_flags & MDB_ENV_ACTIVE))

+		return;

+

+	/* Doing this here since me_dbxs may not exist during mdb_env_close */

+	if (env->me_dbxs) {

+		for (i = env->me_maxdbs; --i >= CORE_DBS; )

+			free(env->me_dbxs[i].md_name.mv_data);

+		free(env->me_dbxs);

+	}

+

+	free(env->me_pbuf);

+	free(env->me_dbiseqs);

+	free(env->me_dbflags);

+	free(env->me_path);

+	free(env->me_dirty_list);

+#ifdef MDB_VL32

+	if (env->me_txn0 && env->me_txn0->mt_rpages)

+		free(env->me_txn0->mt_rpages);

+	{ unsigned int x;

+		for (x=1; x<=env->me_rpages[0].mid; x++)

+		munmap(env->me_rpages[x].mptr, env->me_rpages[x].mcnt * env->me_psize);

+	}

+	free(env->me_rpages);

+#endif

+	free(env->me_txn0);

+	mdb_midl_free(env->me_free_pgs);

+

+	if (env->me_flags & MDB_ENV_TXKEY) {

+		pthread_key_delete(env->me_txkey);

+#ifdef _WIN32

+		/* Delete our key from the global list */

+		for (i=0; i<mdb_tls_nkeys; i++)

+			if (mdb_tls_keys[i] == env->me_txkey) {

+				mdb_tls_keys[i] = mdb_tls_keys[mdb_tls_nkeys-1];

+				mdb_tls_nkeys--;

+				break;

+			}

+#endif

+	}

+

+	if (env->me_map) {

+#ifdef MDB_VL32

+		munmap(env->me_map, NUM_METAS*env->me_psize);

+#else

+		munmap(env->me_map, env->me_mapsize);

+#endif

+	}

+	if (env->me_mfd != env->me_fd && env->me_mfd != INVALID_HANDLE_VALUE)

+		(void) close(env->me_mfd);

+	if (env->me_fd != INVALID_HANDLE_VALUE)

+		(void) close(env->me_fd);

+	if (env->me_txns) {

+		MDB_PID_T pid = env->me_pid;

+		/* Clearing readers is done in this function because

+		 * me_txkey with its destructor must be disabled first.

+		 *

+		 * We skip the the reader mutex, so we touch only

+		 * data owned by this process (me_close_readers and

+		 * our readers), and clear each reader atomically.

+		 */

+		for (i = env->me_close_readers; --i >= 0; )

+			if (env->me_txns->mti_readers[i].mr_pid == pid)

+				env->me_txns->mti_readers[i].mr_pid = 0;

+#ifdef _WIN32

+		if (env->me_rmutex) {

+			CloseHandle(env->me_rmutex);

+			if (env->me_wmutex) CloseHandle(env->me_wmutex);

+		}

+		/* Windows automatically destroys the mutexes when

+		 * the last handle closes.

+		 */

+#elif defined(MDB_USE_POSIX_SEM)

+		if (env->me_rmutex != SEM_FAILED) {

+			sem_close(env->me_rmutex);

+			if (env->me_wmutex != SEM_FAILED)

+				sem_close(env->me_wmutex);

+			/* If we have the filelock:  If we are the

+			 * only remaining user, clean up semaphores.

+			 */

+			if (excl == 0)

+				mdb_env_excl_lock(env, &excl);

+			if (excl > 0) {

+				sem_unlink(env->me_txns->mti_rmname);

+				sem_unlink(env->me_txns->mti_wmname);

+			}

+		}

+#elif defined(MDB_USE_SYSV_SEM)

+		if (env->me_rmutex->semid != -1) {

+			/* If we have the filelock:  If we are the

+			 * only remaining user, clean up semaphores.

+			 */

+			if (excl == 0)

+				mdb_env_excl_lock(env, &excl);

+			if (excl > 0)

+				semctl(env->me_rmutex->semid, 0, IPC_RMID);

+		}

+#endif

+		munmap((void *)env->me_txns, (env->me_maxreaders-1)*sizeof(MDB_reader)+sizeof(MDB_txninfo));

+	}

+	if (env->me_lfd != INVALID_HANDLE_VALUE) {

+#ifdef _WIN32

+		if (excl >= 0) {

+			/* Unlock the lockfile.  Windows would have unlocked it

+			 * after closing anyway, but not necessarily at once.

+			 */

+			UnlockFile(env->me_lfd, 0, 0, 1, 0);

+		}

+#endif

+		(void) close(env->me_lfd);

+	}

+#ifdef MDB_VL32

+#ifdef _WIN32

+	if (env->me_fmh) CloseHandle(env->me_fmh);

+	if (env->me_rpmutex) CloseHandle(env->me_rpmutex);

+#else

+	pthread_mutex_destroy(&env->me_rpmutex);

+#endif

+#endif

+

+	env->me_flags &= ~(MDB_ENV_ACTIVE|MDB_ENV_TXKEY);

+}

+

+void ESECT

+mdb_env_close(MDB_env *env)

+{

+	MDB_page *dp;

+

+	if (env == NULL)

+		return;

+

+	VGMEMP_DESTROY(env);

+	while ((dp = env->me_dpages) != NULL) {

+		VGMEMP_DEFINED(&dp->mp_next, sizeof(dp->mp_next));

+		env->me_dpages = dp->mp_next;

+		free(dp);

+	}

+

+	mdb_env_close0(env, 0);

+	free(env);

+}

+

+/** Compare two items pointing at aligned mdb_size_t's */

+static int

+mdb_cmp_long(const MDB_val *a, const MDB_val *b)

+{

+	return (*(mdb_size_t *)a->mv_data < *(mdb_size_t *)b->mv_data) ? -1 :

+		*(mdb_size_t *)a->mv_data > *(mdb_size_t *)b->mv_data;

+}

+

+/** Compare two items pointing at aligned unsigned int's.

+ *

+ *	This is also set as #MDB_INTEGERDUP|#MDB_DUPFIXED's #MDB_dbx.%md_dcmp,

+ *	but #mdb_cmp_clong() is called instead if the data type is mdb_size_t.

+ */

+static int

+mdb_cmp_int(const MDB_val *a, const MDB_val *b)

+{

+	return (*(unsigned int *)a->mv_data < *(unsigned int *)b->mv_data) ? -1 :

+		*(unsigned int *)a->mv_data > *(unsigned int *)b->mv_data;

+}

+

+/** Compare two items pointing at unsigned ints of unknown alignment.

+ *	Nodes and keys are guaranteed to be 2-byte aligned.

+ */

+static int

+mdb_cmp_cint(const MDB_val *a, const MDB_val *b)

+{

+#if BYTE_ORDER == LITTLE_ENDIAN

+	unsigned short *u, *c;

+	int x;

+

+	u = (unsigned short *) ((char *) a->mv_data + a->mv_size);

+	c = (unsigned short *) ((char *) b->mv_data + a->mv_size);

+	do {

+		x = *--u - *--c;

+	} while(!x && u > (unsigned short *)a->mv_data);

+	return x;

+#else

+	unsigned short *u, *c, *end;

+	int x;

+

+	end = (unsigned short *) ((char *) a->mv_data + a->mv_size);

+	u = (unsigned short *)a->mv_data;

+	c = (unsigned short *)b->mv_data;

+	do {

+		x = *u++ - *c++;

+	} while(!x && u < end);

+	return x;

+#endif

+}

+

+/** Compare two items lexically */

+static int

+mdb_cmp_memn(const MDB_val *a, const MDB_val *b)

+{

+	int diff;

+	ssize_t len_diff;

+	unsigned int len;

+

+	len = a->mv_size;

+	len_diff = (ssize_t) a->mv_size - (ssize_t) b->mv_size;

+	if (len_diff > 0) {

+		len = b->mv_size;

+		len_diff = 1;

+	}

+

+	diff = memcmp(a->mv_data, b->mv_data, len);

+	return diff ? diff : len_diff<0 ? -1 : len_diff;

+}

+

+/** Compare two items in reverse byte order */

+static int

+mdb_cmp_memnr(const MDB_val *a, const MDB_val *b)

+{

+	const unsigned char	*p1, *p2, *p1_lim;

+	ssize_t len_diff;

+	int diff;

+

+	p1_lim = (const unsigned char *)a->mv_data;

+	p1 = (const unsigned char *)a->mv_data + a->mv_size;

+	p2 = (const unsigned char *)b->mv_data + b->mv_size;

+

+	len_diff = (ssize_t) a->mv_size - (ssize_t) b->mv_size;

+	if (len_diff > 0) {

+		p1_lim += len_diff;

+		len_diff = 1;

+	}

+

+	while (p1 > p1_lim) {

+		diff = *--p1 - *--p2;

+		if (diff)

+			return diff;

+	}

+	return len_diff<0 ? -1 : len_diff;

+}

+

+/** Search for key within a page, using binary search.

+ * Returns the smallest entry larger or equal to the key.

+ * If exactp is non-null, stores whether the found entry was an exact match

+ * in *exactp (1 or 0).

+ * Updates the cursor index with the index of the found entry.

+ * If no entry larger or equal to the key is found, returns NULL.

+ */

+static MDB_node *

+mdb_node_search(MDB_cursor *mc, MDB_val *key, int *exactp)

+{

+	unsigned int	 i = 0, nkeys;

+	int		 low, high;

+	int		 rc = 0;

+	MDB_page *mp = mc->mc_pg[mc->mc_top];

+	MDB_node	*node = NULL;

+	MDB_val	 nodekey;

+	MDB_cmp_func *cmp;

+	DKBUF;

+

+	nkeys = NUMKEYS(mp);

+

+	DPRINTF(("searching %u keys in %s %spage %"Y"u",

+	    nkeys, IS_LEAF(mp) ? "leaf" : "branch", IS_SUBP(mp) ? "sub-" : "",

+	    mdb_dbg_pgno(mp)));

+

+	low = IS_LEAF(mp) ? 0 : 1;

+	high = nkeys - 1;

+	cmp = mc->mc_dbx->md_cmp;

+

+	/* Branch pages have no data, so if using integer keys,

+	 * alignment is guaranteed. Use faster mdb_cmp_int.

+	 */

+	if (cmp == mdb_cmp_cint && IS_BRANCH(mp)) {

+		if (NODEPTR(mp, 1)->mn_ksize == sizeof(mdb_size_t))

+			cmp = mdb_cmp_long;

+		else if(NODEPTR(mp, 1)->mn_ksize == sizeof(int))

+			cmp = mdb_cmp_int;

+	}

+

+	if (IS_LEAF2(mp)) {

+		nodekey.mv_size = mc->mc_db->md_pad;

+		node = NODEPTR(mp, 0);	/* fake */

+		while (low <= high) {

+			i = (low + high) >> 1;

+			nodekey.mv_data = LEAF2KEY(mp, i, nodekey.mv_size);

+			rc = cmp(key, &nodekey);

+			DPRINTF(("found leaf index %u [%s], rc = %i",

+			    i, DKEY(&nodekey), rc));

+			if (rc == 0)

+				break;

+			if (rc > 0)

+				low = i + 1;

+			else

+				high = i - 1;

+		}

+	} else {

+		while (low <= high) {

+			i = (low + high) >> 1;

+

+			node = NODEPTR(mp, i);

+			nodekey.mv_size = NODEKSZ(node);

+			nodekey.mv_data = NODEKEY(node);

+

+			rc = cmp(key, &nodekey);

+#if MDB_DEBUG

+			if (IS_LEAF(mp))

+				DPRINTF(("found leaf index %u [%s], rc = %i",

+				    i, DKEY(&nodekey), rc));

+			else

+				DPRINTF(("found branch index %u [%s -> %"Y"u], rc = %i",

+				    i, DKEY(&nodekey), NODEPGNO(node), rc));

+#endif

+			if (rc == 0)

+				break;

+			if (rc > 0)

+				low = i + 1;

+			else

+				high = i - 1;

+		}

+	}

+

+	if (rc > 0) {	/* Found entry is less than the key. */

+		i++;	/* Skip to get the smallest entry larger than key. */

+		if (!IS_LEAF2(mp))

+			node = NODEPTR(mp, i);

+	}

+	if (exactp)

+		*exactp = (rc == 0 && nkeys > 0);

+	/* store the key index */

+	mc->mc_ki[mc->mc_top] = i;

+	if (i >= nkeys)

+		/* There is no entry larger or equal to the key. */

+		return NULL;

+

+	/* nodeptr is fake for LEAF2 */

+	return node;

+}

+

+#if 0

+static void

+mdb_cursor_adjust(MDB_cursor *mc, func)

+{

+	MDB_cursor *m2;

+

+	for (m2 = mc->mc_txn->mt_cursors[mc->mc_dbi]; m2; m2=m2->mc_next) {

+		if (m2->mc_pg[m2->mc_top] == mc->mc_pg[mc->mc_top]) {

+			func(mc, m2);

+		}

+	}

+}

+#endif

+

+/** Pop a page off the top of the cursor's stack. */

+static void

+mdb_cursor_pop(MDB_cursor *mc)

+{

+	if (mc->mc_snum) {

+		DPRINTF(("popping page %"Y"u off db %d cursor %p",

+			mc->mc_pg[mc->mc_top]->mp_pgno, DDBI(mc), (void *) mc));

+

+		mc->mc_snum--;

+		if (mc->mc_snum) {

+			mc->mc_top--;

+		} else {

+			mc->mc_flags &= ~C_INITIALIZED;

+		}

+	}

+}

+

+/** Push a page onto the top of the cursor's stack. */

+static int

+mdb_cursor_push(MDB_cursor *mc, MDB_page *mp)

+{

+	DPRINTF(("pushing page %"Y"u on db %d cursor %p", mp->mp_pgno,

+		DDBI(mc), (void *) mc));

+

+	if (mc->mc_snum >= CURSOR_STACK) {

+		mc->mc_txn->mt_flags |= MDB_TXN_ERROR;

+		return MDB_CURSOR_FULL;

+	}

+

+	mc->mc_top = mc->mc_snum++;

+	mc->mc_pg[mc->mc_top] = mp;

+	mc->mc_ki[mc->mc_top] = 0;

+

+	return MDB_SUCCESS;

+}

+

+#ifdef MDB_VL32

+/** Map a read-only page.

+ * There are two levels of tracking in use, a per-txn list and a per-env list.

+ * ref'ing and unref'ing the per-txn list is faster since it requires no

+ * locking. Pages are cached in the per-env list for global reuse, and a lock

+ * is required. Pages are not immediately unmapped when their refcnt goes to

+ * zero; they hang around in case they will be reused again soon.

+ *

+ * When the per-txn list gets full, all pages with refcnt=0 are purged from the

+ * list and their refcnts in the per-env list are decremented.

+ *

+ * When the per-env list gets full, all pages with refcnt=0 are purged from the

+ * list and their pages are unmapped.

+ *

+ * @note "full" means the list has reached its respective rpcheck threshold.

+ * This threshold slowly raises if no pages could be purged on a given check,

+ * and returns to its original value when enough pages were purged.

+ *

+ * If purging doesn't free any slots, filling the per-txn list will return

+ * MDB_TXN_FULL, and filling the per-env list returns MDB_MAP_FULL.

+ *

+ * Reference tracking in a txn is imperfect, pages can linger with non-zero

+ * refcnt even without active references. It was deemed to be too invasive

+ * to add unrefs in every required location. However, all pages are unref'd

+ * at the end of the transaction. This guarantees that no stale references

+ * linger in the per-env list.

+ *

+ * Usually we map chunks of 16 pages at a time, but if an overflow page begins

+ * at the tail of the chunk we extend the chunk to include the entire overflow

+ * page. Unfortunately, pages can be turned into overflow pages after their

+ * chunk was already mapped. In that case we must remap the chunk if the

+ * overflow page is referenced. If the chunk's refcnt is 0 we can just remap

+ * it, otherwise we temporarily map a new chunk just for the overflow page.

+ *

+ * @note this chunk handling means we cannot guarantee that a data item

+ * returned from the DB will stay alive for the duration of the transaction:

+ *   We unref pages as soon as a cursor moves away from the page

+ *   A subsequent op may cause a purge, which may unmap any unref'd chunks

+ * The caller must copy the data if it must be used later in the same txn.

+ *

+ * Also - our reference counting revolves around cursors, but overflow pages

+ * aren't pointed to by a cursor's page stack. We have to remember them

+ * explicitly, in the added mc_ovpg field. A single cursor can only hold a

+ * reference to one overflow page at a time.

+ *

+ * @param[in] txn the transaction for this access.

+ * @param[in] pgno the page number for the page to retrieve.

+ * @param[out] ret address of a pointer where the page's address will be stored.

+ * @return 0 on success, non-zero on failure.

+ */

+static int

+mdb_rpage_get(MDB_txn *txn, pgno_t pg0, MDB_page **ret)

+{

+	MDB_env *env = txn->mt_env;

+	MDB_page *p;

+	MDB_ID3L tl = txn->mt_rpages;

+	MDB_ID3L el = env->me_rpages;

+	MDB_ID3 id3;

+	unsigned x, rem;

+	pgno_t pgno;

+	int rc, retries = 1;

+#ifdef _WIN32

+	LARGE_INTEGER off;

+	SIZE_T len;

+#define SET_OFF(off,val)	off.QuadPart = val

+#define MAP(rc,env,addr,len,off)	\

+	addr = NULL; \

+	rc = NtMapViewOfSection(env->me_fmh, GetCurrentProcess(), &addr, 0, \

+		len, &off, &len, ViewUnmap, (env->me_flags & MDB_RDONLY) ? 0 : MEM_RESERVE, PAGE_READONLY); \

+	if (rc) rc = mdb_nt2win32(rc)

+#else

+	off_t off;

+	size_t len;

+#define SET_OFF(off,val)	off = val

+#define MAP(rc,env,addr,len,off)	\

+	addr = mmap(NULL, len, PROT_READ, MAP_SHARED, env->me_fd, off); \

+	rc = (addr == MAP_FAILED) ? errno : 0

+#endif

+

+	/* remember the offset of the actual page number, so we can

+	 * return the correct pointer at the end.

+	 */

+	rem = pg0 & (MDB_RPAGE_CHUNK-1);

+	pgno = pg0 ^ rem;

+

+	id3.mid = 0;

+	x = mdb_mid3l_search(tl, pgno);

+	if (x <= tl[0].mid && tl[x].mid == pgno) {

+		if (x != tl[0].mid && tl[x+1].mid == pg0)

+			x++;

+		/* check for overflow size */

+		p = (MDB_page *)((char *)tl[x].mptr + rem * env->me_psize);

+		if (IS_OVERFLOW(p) && p->mp_pages + rem > tl[x].mcnt) {

+			id3.mcnt = p->mp_pages + rem;

+			len = id3.mcnt * env->me_psize;

+			SET_OFF(off, pgno * env->me_psize);

+			MAP(rc, env, id3.mptr, len, off);

+			if (rc)

+				return rc;

+			/* check for local-only page */

+			if (rem) {

+				mdb_tassert(txn, tl[x].mid != pg0);

+				/* hope there's room to insert this locally.

+				 * setting mid here tells later code to just insert

+				 * this id3 instead of searching for a match.

+				 */

+				id3.mid = pg0;

+				goto notlocal;

+			} else {

+				/* ignore the mapping we got from env, use new one */

+				tl[x].mptr = id3.mptr;

+				tl[x].mcnt = id3.mcnt;

+				/* if no active ref, see if we can replace in env */

+				if (!tl[x].mref) {

+					unsigned i;

+					pthread_mutex_lock(&env->me_rpmutex);

+					i = mdb_mid3l_search(el, tl[x].mid);

+					if (el[i].mref == 1) {

+						/* just us, replace it */

+						munmap(el[i].mptr, el[i].mcnt * env->me_psize);

+						el[i].mptr = tl[x].mptr;

+						el[i].mcnt = tl[x].mcnt;

+					} else {

+						/* there are others, remove ourself */

+						el[i].mref--;

+					}

+					pthread_mutex_unlock(&env->me_rpmutex);

+				}

+			}

+		}

+		id3.mptr = tl[x].mptr;

+		id3.mcnt = tl[x].mcnt;

+		tl[x].mref++;

+		goto ok;

+	}

+

+notlocal:

+	if (tl[0].mid >= MDB_TRPAGE_MAX - txn->mt_rpcheck) {

+		unsigned i, y;

+		/* purge unref'd pages from our list and unref in env */

+		pthread_mutex_lock(&env->me_rpmutex);

+retry:

+		y = 0;

+		for (i=1; i<=tl[0].mid; i++) {

+			if (!tl[i].mref) {

+				if (!y) y = i;

+				/* tmp overflow pages don't go to env */

+				if (tl[i].mid & (MDB_RPAGE_CHUNK-1)) {

+					munmap(tl[i].mptr, tl[i].mcnt * env->me_psize);

+					continue;

+				}

+				x = mdb_mid3l_search(el, tl[i].mid);

+				el[x].mref--;

+			}

+		}

+		pthread_mutex_unlock(&env->me_rpmutex);

+		if (!y) {

+			/* we didn't find any unref'd chunks.

+			 * if we're out of room, fail.

+			 */

+			if (tl[0].mid >= MDB_TRPAGE_MAX)

+				return MDB_TXN_FULL;

+			/* otherwise, raise threshold for next time around

+			 * and let this go.

+			 */

+			txn->mt_rpcheck /= 2;

+		} else {

+			/* we found some unused; consolidate the list */

+			for (i=y+1; i<= tl[0].mid; i++)

+				if (tl[i].mref)

+					tl[y++] = tl[i];

+			tl[0].mid = y-1;

+			/* decrease the check threshold toward its original value */

+			if (!txn->mt_rpcheck)

+				txn->mt_rpcheck = 1;

+			while (txn->mt_rpcheck < tl[0].mid && txn->mt_rpcheck < MDB_TRPAGE_SIZE/2)

+				txn->mt_rpcheck *= 2;

+		}

+	}

+	if (tl[0].mid < MDB_TRPAGE_SIZE) {

+		id3.mref = 1;

+		if (id3.mid)

+			goto found;

+		/* don't map past last written page in read-only envs */

+		if ((env->me_flags & MDB_RDONLY) && pgno + MDB_RPAGE_CHUNK-1 > txn->mt_last_pgno)

+			id3.mcnt = txn->mt_last_pgno + 1 - pgno;

+		else

+			id3.mcnt = MDB_RPAGE_CHUNK;

+		len = id3.mcnt * env->me_psize;

+		id3.mid = pgno;

+

+		/* search for page in env */

+		pthread_mutex_lock(&env->me_rpmutex);

+		x = mdb_mid3l_search(el, pgno);

+		if (x <= el[0].mid && el[x].mid == pgno) {

+			id3.mptr = el[x].mptr;

+			id3.mcnt = el[x].mcnt;

+			/* check for overflow size */

+			p = (MDB_page *)((char *)id3.mptr + rem * env->me_psize);

+			if (IS_OVERFLOW(p) && p->mp_pages + rem > id3.mcnt) {

+				id3.mcnt = p->mp_pages + rem;

+				len = id3.mcnt * env->me_psize;

+				SET_OFF(off, pgno * env->me_psize);

+				MAP(rc, env, id3.mptr, len, off);

+				if (rc)

+					goto fail;

+				if (!el[x].mref) {

+					munmap(el[x].mptr, env->me_psize * el[x].mcnt);

+					el[x].mptr = id3.mptr;

+					el[x].mcnt = id3.mcnt;

+				} else {

+					id3.mid = pg0;

+					pthread_mutex_unlock(&env->me_rpmutex);

+					goto found;

+				}

+			}

+			el[x].mref++;

+			pthread_mutex_unlock(&env->me_rpmutex);

+			goto found;

+		}

+		if (el[0].mid >= MDB_ERPAGE_MAX - env->me_rpcheck) {

+			/* purge unref'd pages */

+			unsigned i, y = 0;

+			for (i=1; i<=el[0].mid; i++) {

+				if (!el[i].mref) {

+					if (!y) y = i;

+					munmap(el[i].mptr, env->me_psize * el[i].mcnt);

+				}

+			}

+			if (!y) {

+				if (retries) {

+					/* see if we can unref some local pages */

+					retries--;

+					id3.mid = 0;

+					goto retry;

+				}

+				if (el[0].mid >= MDB_ERPAGE_MAX) {

+					pthread_mutex_unlock(&env->me_rpmutex);

+					return MDB_MAP_FULL;

+				}

+				env->me_rpcheck /= 2;

+			} else {

+				for (i=y+1; i<= el[0].mid; i++)

+					if (el[i].mref)

+						el[y++] = el[i];

+				el[0].mid = y-1;

+				if (!env->me_rpcheck)

+					env->me_rpcheck = 1;

+				while (env->me_rpcheck < el[0].mid && env->me_rpcheck < MDB_ERPAGE_SIZE/2)

+					env->me_rpcheck *= 2;

+			}

+		}

+		SET_OFF(off, pgno * env->me_psize);

+		MAP(rc, env, id3.mptr, len, off);

+		if (rc) {

+fail:

+			pthread_mutex_unlock(&env->me_rpmutex);

+			return rc;

+		}

+		/* check for overflow size */

+		p = (MDB_page *)((char *)id3.mptr + rem * env->me_psize);

+		if (IS_OVERFLOW(p) && p->mp_pages + rem > id3.mcnt) {

+			id3.mcnt = p->mp_pages + rem;

+			munmap(id3.mptr, len);

+			len = id3.mcnt * env->me_psize;

+			MAP(rc, env, id3.mptr, len, off);

+			if (rc)

+				goto fail;

+		}

+		mdb_mid3l_insert(el, &id3);

+		pthread_mutex_unlock(&env->me_rpmutex);

+found:

+		mdb_mid3l_insert(tl, &id3);

+	} else {

+		return MDB_TXN_FULL;

+	}

+ok:

+	p = (MDB_page *)((char *)id3.mptr + rem * env->me_psize);

+#if MDB_DEBUG	/* we don't need this check any more */

+	if (IS_OVERFLOW(p)) {

+		mdb_tassert(txn, p->mp_pages + rem <= id3.mcnt);

+	}

+#endif

+	*ret = p;

+	return MDB_SUCCESS;

+}

+#endif

+

+/** Find the address of the page corresponding to a given page number.

+ * @param[in] mc the cursor accessing the page.

+ * @param[in] pgno the page number for the page to retrieve.

+ * @param[out] ret address of a pointer where the page's address will be stored.

+ * @param[out] lvl dirty_list inheritance level of found page. 1=current txn, 0=mapped page.

+ * @return 0 on success, non-zero on failure.

+ */

+static int

+mdb_page_get(MDB_cursor *mc, pgno_t pgno, MDB_page **ret, int *lvl)

+{

+	MDB_txn *txn = mc->mc_txn;

+#ifndef MDB_VL32

+	MDB_env *env = txn->mt_env;

+#endif

+	MDB_page *p = NULL;

+	int level;

+

+	if (! (mc->mc_flags & (C_ORIG_RDONLY|C_WRITEMAP))) {

+		MDB_txn *tx2 = txn;

+		level = 1;

+		do {

+			MDB_ID2L dl = tx2->mt_u.dirty_list;

+			unsigned x;

+			/* Spilled pages were dirtied in this txn and flushed

+			 * because the dirty list got full. Bring this page

+			 * back in from the map (but don't unspill it here,

+			 * leave that unless page_touch happens again).

+			 */

+			if (tx2->mt_spill_pgs) {

+				MDB_ID pn = pgno << 1;

+				x = mdb_midl_search(tx2->mt_spill_pgs, pn);

+				if (x <= tx2->mt_spill_pgs[0] && tx2->mt_spill_pgs[x] == pn) {

+#ifdef MDB_VL32

+					int rc = mdb_rpage_get(txn, pgno, &p);

+					if (rc)

+						return rc;

+#else

+					p = (MDB_page *)(env->me_map + env->me_psize * pgno);

+#endif

+					goto done;

+				}

+			}

+			if (dl[0].mid) {

+				unsigned x = mdb_mid2l_search(dl, pgno);

+				if (x <= dl[0].mid && dl[x].mid == pgno) {

+					p = dl[x].mptr;

+					goto done;

+				}

+			}

+			level++;

+		} while ((tx2 = tx2->mt_parent) != NULL);

+	}

+

+	if (pgno < txn->mt_next_pgno) {

+		level = 0;

+#ifdef MDB_VL32

+		{

+			int rc = mdb_rpage_get(txn, pgno, &p);

+			if (rc)

+				return rc;

+		}

+#else

+		p = (MDB_page *)(env->me_map + env->me_psize * pgno);

+#endif

+	} else {

+		DPRINTF(("page %"Y"u not found", pgno));

+		txn->mt_flags |= MDB_TXN_ERROR;

+		return MDB_PAGE_NOTFOUND;

+	}

+

+done:

+	*ret = p;

+	if (lvl)

+		*lvl = level;

+	return MDB_SUCCESS;

+}

+

+/** Finish #mdb_page_search() / #mdb_page_search_lowest().

+ *	The cursor is at the root page, set up the rest of it.

+ */

+static int

+mdb_page_search_root(MDB_cursor *mc, MDB_val *key, int flags)

+{

+	MDB_page	*mp = mc->mc_pg[mc->mc_top];

+	int rc;

+	DKBUF;

+

+	while (IS_BRANCH(mp)) {

+		MDB_node	*node;

+		indx_t		i;

+

+		DPRINTF(("branch page %"Y"u has %u keys", mp->mp_pgno, NUMKEYS(mp)));

+		/* Don't assert on branch pages in the FreeDB. We can get here

+		 * while in the process of rebalancing a FreeDB branch page; we must

+		 * let that proceed. ITS#8336

+		 */

+		mdb_cassert(mc, !mc->mc_dbi || NUMKEYS(mp) > 1);

+		DPRINTF(("found index 0 to page %"Y"u", NODEPGNO(NODEPTR(mp, 0))));

+

+		if (flags & (MDB_PS_FIRST|MDB_PS_LAST)) {

+			i = 0;

+			if (flags & MDB_PS_LAST)

+				i = NUMKEYS(mp) - 1;

+		} else {

+			int	 exact;

+			node = mdb_node_search(mc, key, &exact);

+			if (node == NULL)

+				i = NUMKEYS(mp) - 1;

+			else {

+				i = mc->mc_ki[mc->mc_top];

+				if (!exact) {

+					mdb_cassert(mc, i > 0);

+					i--;

+				}

+			}

+			DPRINTF(("following index %u for key [%s]", i, DKEY(key)));

+		}

+

+		mdb_cassert(mc, i < NUMKEYS(mp));

+		node = NODEPTR(mp, i);

+

+		if ((rc = mdb_page_get(mc, NODEPGNO(node), &mp, NULL)) != 0)

+			return rc;

+

+		mc->mc_ki[mc->mc_top] = i;

+		if ((rc = mdb_cursor_push(mc, mp)))

+			return rc;

+

+		if (flags & MDB_PS_MODIFY) {

+			if ((rc = mdb_page_touch(mc)) != 0)

+				return rc;

+			mp = mc->mc_pg[mc->mc_top];

+		}

+	}

+

+	if (!IS_LEAF(mp)) {

+		DPRINTF(("internal error, index points to a %02X page!?",

+		    mp->mp_flags));

+		mc->mc_txn->mt_flags |= MDB_TXN_ERROR;

+		return MDB_CORRUPTED;

+	}

+

+	DPRINTF(("found leaf page %"Y"u for key [%s]", mp->mp_pgno,

+	    key ? DKEY(key) : "null"));

+	mc->mc_flags |= C_INITIALIZED;

+	mc->mc_flags &= ~C_EOF;

+

+	return MDB_SUCCESS;

+}

+

+/** Search for the lowest key under the current branch page.

+ * This just bypasses a NUMKEYS check in the current page

+ * before calling mdb_page_search_root(), because the callers

+ * are all in situations where the current page is known to

+ * be underfilled.

+ */

+static int

+mdb_page_search_lowest(MDB_cursor *mc)

+{

+	MDB_page	*mp = mc->mc_pg[mc->mc_top];

+	MDB_node	*node = NODEPTR(mp, 0);

+	int rc;

+

+	if ((rc = mdb_page_get(mc, NODEPGNO(node), &mp, NULL)) != 0)

+		return rc;

+

+	mc->mc_ki[mc->mc_top] = 0;

+	if ((rc = mdb_cursor_push(mc, mp)))

+		return rc;

+	return mdb_page_search_root(mc, NULL, MDB_PS_FIRST);

+}

+

+/** Search for the page a given key should be in.

+ * Push it and its parent pages on the cursor stack.

+ * @param[in,out] mc the cursor for this operation.

+ * @param[in] key the key to search for, or NULL for first/last page.

+ * @param[in] flags If MDB_PS_MODIFY is set, visited pages in the DB

+ *   are touched (updated with new page numbers).

+ *   If MDB_PS_FIRST or MDB_PS_LAST is set, find first or last leaf.

+ *   This is used by #mdb_cursor_first() and #mdb_cursor_last().

+ *   If MDB_PS_ROOTONLY set, just fetch root node, no further lookups.

+ * @return 0 on success, non-zero on failure.

+ */

+static int

+mdb_page_search(MDB_cursor *mc, MDB_val *key, int flags)

+{

+	int		 rc;

+	pgno_t		 root;

+

+	/* Make sure the txn is still viable, then find the root from

+	 * the txn's db table and set it as the root of the cursor's stack.

+	 */

+	if (mc->mc_txn->mt_flags & MDB_TXN_BLOCKED) {

+		DPUTS("transaction may not be used now");

+		return MDB_BAD_TXN;

+	} else {

+		/* Make sure we're using an up-to-date root */

+		if (*mc->mc_dbflag & DB_STALE) {

+				MDB_cursor mc2;

+				if (TXN_DBI_CHANGED(mc->mc_txn, mc->mc_dbi))

+					return MDB_BAD_DBI;

+				mdb_cursor_init(&mc2, mc->mc_txn, MAIN_DBI, NULL);

+				rc = mdb_page_search(&mc2, &mc->mc_dbx->md_name, 0);

+				if (rc)

+					return rc;

+				{

+					MDB_val data;

+					int exact = 0;

+					uint16_t flags;

+					MDB_node *leaf = mdb_node_search(&mc2,

+						&mc->mc_dbx->md_name, &exact);

+					if (!exact)

+						return MDB_NOTFOUND;

+					if ((leaf->mn_flags & (F_DUPDATA|F_SUBDATA)) != F_SUBDATA)

+						return MDB_INCOMPATIBLE; /* not a named DB */

+					rc = mdb_node_read(&mc2, leaf, &data);

+					if (rc)

+						return rc;

+					memcpy(&flags, ((char *) data.mv_data + offsetof(MDB_db, md_flags)),

+						sizeof(uint16_t));

+					/* The txn may not know this DBI, or another process may

+					 * have dropped and recreated the DB with other flags.

+					 */

+					if ((mc->mc_db->md_flags & PERSISTENT_FLAGS) != flags)

+						return MDB_INCOMPATIBLE;

+					memcpy(mc->mc_db, data.mv_data, sizeof(MDB_db));

+				}

+				*mc->mc_dbflag &= ~DB_STALE;

+		}

+		root = mc->mc_db->md_root;

+

+		if (root == P_INVALID) {		/* Tree is empty. */

+			DPUTS("tree is empty");

+			return MDB_NOTFOUND;

+		}

+	}

+

+	mdb_cassert(mc, root > 1);

+	if (!mc->mc_pg[0] || mc->mc_pg[0]->mp_pgno != root) {

+#ifdef MDB_VL32

+		if (mc->mc_pg[0])

+			MDB_PAGE_UNREF(mc->mc_txn, mc->mc_pg[0]);

+#endif

+		if ((rc = mdb_page_get(mc, root, &mc->mc_pg[0], NULL)) != 0)

+			return rc;

+	}

+

+#ifdef MDB_VL32

+	{

+		int i;

+		for (i=1; i<mc->mc_snum; i++)

+			MDB_PAGE_UNREF(mc->mc_txn, mc->mc_pg[i]);

+	}

+#endif

+	mc->mc_snum = 1;

+	mc->mc_top = 0;

+

+	DPRINTF(("db %d root page %"Y"u has flags 0x%X",

+		DDBI(mc), root, mc->mc_pg[0]->mp_flags));

+

+	if (flags & MDB_PS_MODIFY) {

+		if ((rc = mdb_page_touch(mc)))

+			return rc;

+	}

+

+	if (flags & MDB_PS_ROOTONLY)

+		return MDB_SUCCESS;

+

+	return mdb_page_search_root(mc, key, flags);

+}

+

+static int

+mdb_ovpage_free(MDB_cursor *mc, MDB_page *mp)

+{

+	MDB_txn *txn = mc->mc_txn;

+	pgno_t pg = mp->mp_pgno;

+	unsigned x = 0, ovpages = mp->mp_pages;

+	MDB_env *env = txn->mt_env;

+	MDB_IDL sl = txn->mt_spill_pgs;

+	MDB_ID pn = pg << 1;

+	int rc;

+

+	DPRINTF(("free ov page %"Y"u (%d)", pg, ovpages));

+	/* If the page is dirty or on the spill list we just acquired it,

+	 * so we should give it back to our current free list, if any.

+	 * Otherwise put it onto the list of pages we freed in this txn.

+	 *

+	 * Won't create me_pghead: me_pglast must be inited along with it.

+	 * Unsupported in nested txns: They would need to hide the page

+	 * range in ancestor txns' dirty and spilled lists.

+	 */

+	if (env->me_pghead &&

+		!txn->mt_parent &&

+		((mp->mp_flags & P_DIRTY) ||

+		 (sl && (x = mdb_midl_search(sl, pn)) <= sl[0] && sl[x] == pn)))

+	{

+		unsigned i, j;

+		pgno_t *mop;

+		MDB_ID2 *dl, ix, iy;

+		rc = mdb_midl_need(&env->me_pghead, ovpages);

+		if (rc)

+			return rc;

+		if (!(mp->mp_flags & P_DIRTY)) {

+			/* This page is no longer spilled */

+			if (x == sl[0])

+				sl[0]--;

+			else

+				sl[x] |= 1;

+			goto release;

+		}

+		/* Remove from dirty list */

+		dl = txn->mt_u.dirty_list;

+		x = dl[0].mid--;

+		for (ix = dl[x]; ix.mptr != mp; ix = iy) {

+			if (x > 1) {

+				x--;

+				iy = dl[x];

+				dl[x] = ix;

+			} else {

+				mdb_cassert(mc, x > 1);

+				j = ++(dl[0].mid);

+				dl[j] = ix;		/* Unsorted. OK when MDB_TXN_ERROR. */

+				txn->mt_flags |= MDB_TXN_ERROR;

+				return MDB_CORRUPTED;

+			}

+		}

+		txn->mt_dirty_room++;

+		if (!(env->me_flags & MDB_WRITEMAP))

+			mdb_dpage_free(env, mp);

+release:

+		/* Insert in me_pghead */

+		mop = env->me_pghead;

+		j = mop[0] + ovpages;

+		for (i = mop[0]; i && mop[i] < pg; i--)

+			mop[j--] = mop[i];

+		while (j>i)

+			mop[j--] = pg++;

+		mop[0] += ovpages;

+	} else {

+		rc = mdb_midl_append_range(&txn->mt_free_pgs, pg, ovpages);

+		if (rc)

+			return rc;

+	}

+	mc->mc_db->md_overflow_pages -= ovpages;

+	return 0;

+}

+

+/** Return the data associated with a given node.

+ * @param[in] mc The cursor for this operation.

+ * @param[in] leaf The node being read.

+ * @param[out] data Updated to point to the node's data.

+ * @return 0 on success, non-zero on failure.

+ */

+static int

+mdb_node_read(MDB_cursor *mc, MDB_node *leaf, MDB_val *data)

+{

+	MDB_page	*omp;		/* overflow page */

+	pgno_t		 pgno;

+	int rc;

+

+#ifdef MDB_VL32

+	if (mc->mc_ovpg) {

+		MDB_PAGE_UNREF(mc->mc_txn, mc->mc_ovpg);

+		mc->mc_ovpg = 0;

+	}

+#endif

+	if (!F_ISSET(leaf->mn_flags, F_BIGDATA)) {

+		data->mv_size = NODEDSZ(leaf);

+		data->mv_data = NODEDATA(leaf);

+		return MDB_SUCCESS;

+	}

+

+	/* Read overflow data.

+	 */

+	data->mv_size = NODEDSZ(leaf);

+	memcpy(&pgno, NODEDATA(leaf), sizeof(pgno));

+	if ((rc = mdb_page_get(mc, pgno, &omp, NULL)) != 0) {

+		DPRINTF(("read overflow page %"Y"u failed", pgno));

+		return rc;

+	}

+	data->mv_data = METADATA(omp);

+#ifdef MDB_VL32

+	mc->mc_ovpg = omp;

+#endif

+

+	return MDB_SUCCESS;

+}

+

+int

+mdb_get(MDB_txn *txn, MDB_dbi dbi,

+    MDB_val *key, MDB_val *data)

+{

+	MDB_cursor	mc;

+	MDB_xcursor	mx;

+	int exact = 0, rc;

+	DKBUF;

+

+	DPRINTF(("===> get db %u key [%s]", dbi, DKEY(key)));

+

+	if (!key || !data || !TXN_DBI_EXIST(txn, dbi, DB_USRVALID))

+		return EINVAL;

+

+	if (txn->mt_flags & MDB_TXN_BLOCKED)

+		return MDB_BAD_TXN;

+

+	mdb_cursor_init(&mc, txn, dbi, &mx);

+	rc = mdb_cursor_set(&mc, key, data, MDB_SET, &exact);

+#ifdef MDB_VL32

+	{

+		/* unref all the pages - caller must copy the data

+		 * before doing anything else

+		 */

+		mdb_cursor_unref(&mc);

+	}

+#endif

+	return rc;

+}

+

+/** Find a sibling for a page.

+ * Replaces the page at the top of the cursor's stack with the

+ * specified sibling, if one exists.

+ * @param[in] mc The cursor for this operation.

+ * @param[in] move_right Non-zero if the right sibling is requested,

+ * otherwise the left sibling.

+ * @return 0 on success, non-zero on failure.

+ */

+static int

+mdb_cursor_sibling(MDB_cursor *mc, int move_right)

+{

+	int		 rc;

+	MDB_node	*indx;

+	MDB_page	*mp;

+#ifdef MDB_VL32

+	MDB_page	*op;

+#endif

+

+	if (mc->mc_snum < 2) {

+		return MDB_NOTFOUND;		/* root has no siblings */

+	}

+

+#ifdef MDB_VL32

+	op = mc->mc_pg[mc->mc_top];

+#endif

+	mdb_cursor_pop(mc);

+	DPRINTF(("parent page is page %"Y"u, index %u",

+		mc->mc_pg[mc->mc_top]->mp_pgno, mc->mc_ki[mc->mc_top]));

+

+	if (move_right ? (mc->mc_ki[mc->mc_top] + 1u >= NUMKEYS(mc->mc_pg[mc->mc_top]))

+		       : (mc->mc_ki[mc->mc_top] == 0)) {

+		DPRINTF(("no more keys left, moving to %s sibling",

+		    move_right ? "right" : "left"));

+		if ((rc = mdb_cursor_sibling(mc, move_right)) != MDB_SUCCESS) {

+			/* undo cursor_pop before returning */

+			mc->mc_top++;

+			mc->mc_snum++;

+			return rc;

+		}

+	} else {

+		if (move_right)

+			mc->mc_ki[mc->mc_top]++;

+		else

+			mc->mc_ki[mc->mc_top]--;

+		DPRINTF(("just moving to %s index key %u",

+		    move_right ? "right" : "left", mc->mc_ki[mc->mc_top]));

+	}

+	mdb_cassert(mc, IS_BRANCH(mc->mc_pg[mc->mc_top]));

+

+	MDB_PAGE_UNREF(mc->mc_txn, op);

+

+	indx = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);

+	if ((rc = mdb_page_get(mc, NODEPGNO(indx), &mp, NULL)) != 0) {

+		/* mc will be inconsistent if caller does mc_snum++ as above */

+		mc->mc_flags &= ~(C_INITIALIZED|C_EOF);

+		return rc;

+	}

+

+	mdb_cursor_push(mc, mp);

+	if (!move_right)

+		mc->mc_ki[mc->mc_top] = NUMKEYS(mp)-1;

+

+	return MDB_SUCCESS;

+}

+

+/** Move the cursor to the next data item. */

+static int

+mdb_cursor_next(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op)

+{

+	MDB_page	*mp;

+	MDB_node	*leaf;

+	int rc;

+

+	if (mc->mc_flags & C_EOF) {

+		return MDB_NOTFOUND;

+	}

+	if (!(mc->mc_flags & C_INITIALIZED))

+		return mdb_cursor_first(mc, key, data);

+

+	mp = mc->mc_pg[mc->mc_top];

+

+	if (mc->mc_db->md_flags & MDB_DUPSORT) {

+		leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);

+		if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {

+			if (op == MDB_NEXT || op == MDB_NEXT_DUP) {

+				rc = mdb_cursor_next(&mc->mc_xcursor->mx_cursor, data, NULL, MDB_NEXT);

+				if (op != MDB_NEXT || rc != MDB_NOTFOUND) {

+					if (rc == MDB_SUCCESS)

+						MDB_GET_KEY(leaf, key);

+					return rc;

+				}

+			}

+#ifdef MDB_VL32

+			else {

+				if (mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED) {

+					mdb_cursor_unref(&mc->mc_xcursor->mx_cursor);

+				}

+			}

+#endif

+		} else {

+			mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);

+			if (op == MDB_NEXT_DUP)

+				return MDB_NOTFOUND;

+		}

+	}

+

+	DPRINTF(("cursor_next: top page is %"Y"u in cursor %p",

+		mdb_dbg_pgno(mp), (void *) mc));

+	if (mc->mc_flags & C_DEL) {

+		mc->mc_flags ^= C_DEL;

+		goto skip;

+	}

+

+	if (mc->mc_ki[mc->mc_top] + 1u >= NUMKEYS(mp)) {

+		DPUTS("=====> move to next sibling page");

+		if ((rc = mdb_cursor_sibling(mc, 1)) != MDB_SUCCESS) {

+			mc->mc_flags |= C_EOF;

+			return rc;

+		}

+		mp = mc->mc_pg[mc->mc_top];

+		DPRINTF(("next page is %"Y"u, key index %u", mp->mp_pgno, mc->mc_ki[mc->mc_top]));

+	} else

+		mc->mc_ki[mc->mc_top]++;

+

+skip:

+	DPRINTF(("==> cursor points to page %"Y"u with %u keys, key index %u",

+	    mdb_dbg_pgno(mp), NUMKEYS(mp), mc->mc_ki[mc->mc_top]));

+

+	if (IS_LEAF2(mp)) {

+		key->mv_size = mc->mc_db->md_pad;

+		key->mv_data = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], key->mv_size);

+		return MDB_SUCCESS;

+	}

+

+	mdb_cassert(mc, IS_LEAF(mp));

+	leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);

+

+	if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {

+		mdb_xcursor_init1(mc, leaf);

+	}

+	if (data) {

+		if ((rc = mdb_node_read(mc, leaf, data)) != MDB_SUCCESS)

+			return rc;

+

+		if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {

+			rc = mdb_cursor_first(&mc->mc_xcursor->mx_cursor, data, NULL);

+			if (rc != MDB_SUCCESS)

+				return rc;

+		}

+	}

+

+	MDB_GET_KEY(leaf, key);

+	return MDB_SUCCESS;

+}

+

+/** Move the cursor to the previous data item. */

+static int

+mdb_cursor_prev(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op)

+{

+	MDB_page	*mp;

+	MDB_node	*leaf;

+	int rc;

+

+	if (!(mc->mc_flags & C_INITIALIZED)) {

+		rc = mdb_cursor_last(mc, key, data);

+		if (rc)

+			return rc;

+		mc->mc_ki[mc->mc_top]++;

+	}

+

+	mp = mc->mc_pg[mc->mc_top];

+

+	if (mc->mc_db->md_flags & MDB_DUPSORT) {

+		leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);

+		if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {

+			if (op == MDB_PREV || op == MDB_PREV_DUP) {

+				rc = mdb_cursor_prev(&mc->mc_xcursor->mx_cursor, data, NULL, MDB_PREV);

+				if (op != MDB_PREV || rc != MDB_NOTFOUND) {

+					if (rc == MDB_SUCCESS) {

+						MDB_GET_KEY(leaf, key);

+						mc->mc_flags &= ~C_EOF;

+					}

+					return rc;

+				}

+			}

+#ifdef MDB_VL32

+			else {

+				if (mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED) {

+					mdb_cursor_unref(&mc->mc_xcursor->mx_cursor);

+				}

+			}

+#endif

+		} else {

+			mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);

+			if (op == MDB_PREV_DUP)

+				return MDB_NOTFOUND;

+		}

+	}

+

+	DPRINTF(("cursor_prev: top page is %"Y"u in cursor %p",

+		mdb_dbg_pgno(mp), (void *) mc));

+

+	mc->mc_flags &= ~(C_EOF|C_DEL);

+

+	if (mc->mc_ki[mc->mc_top] == 0)  {

+		DPUTS("=====> move to prev sibling page");

+		if ((rc = mdb_cursor_sibling(mc, 0)) != MDB_SUCCESS) {

+			return rc;

+		}

+		mp = mc->mc_pg[mc->mc_top];

+		mc->mc_ki[mc->mc_top] = NUMKEYS(mp) - 1;

+		DPRINTF(("prev page is %"Y"u, key index %u", mp->mp_pgno, mc->mc_ki[mc->mc_top]));

+	} else

+		mc->mc_ki[mc->mc_top]--;

+

+	mc->mc_flags &= ~C_EOF;

+

+	DPRINTF(("==> cursor points to page %"Y"u with %u keys, key index %u",

+	    mdb_dbg_pgno(mp), NUMKEYS(mp), mc->mc_ki[mc->mc_top]));

+

+	if (IS_LEAF2(mp)) {

+		key->mv_size = mc->mc_db->md_pad;

+		key->mv_data = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], key->mv_size);

+		return MDB_SUCCESS;

+	}

+

+	mdb_cassert(mc, IS_LEAF(mp));

+	leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);

+

+	if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {

+		mdb_xcursor_init1(mc, leaf);

+	}

+	if (data) {

+		if ((rc = mdb_node_read(mc, leaf, data)) != MDB_SUCCESS)

+			return rc;

+

+		if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {

+			rc = mdb_cursor_last(&mc->mc_xcursor->mx_cursor, data, NULL);

+			if (rc != MDB_SUCCESS)

+				return rc;

+		}

+	}

+

+	MDB_GET_KEY(leaf, key);

+	return MDB_SUCCESS;

+}

+

+/** Set the cursor on a specific data item. */

+static int

+mdb_cursor_set(MDB_cursor *mc, MDB_val *key, MDB_val *data,

+    MDB_cursor_op op, int *exactp)

+{

+	int		 rc;

+	MDB_page	*mp;

+	MDB_node	*leaf = NULL;

+	DKBUF;

+

+	if (key->mv_size == 0)

+		return MDB_BAD_VALSIZE;

+

+	if (mc->mc_xcursor)

+		mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);

+

+	/* See if we're already on the right page */

+	if (mc->mc_flags & C_INITIALIZED) {

+		MDB_val nodekey;

+

+		mp = mc->mc_pg[mc->mc_top];

+		if (!NUMKEYS(mp)) {

+			mc->mc_ki[mc->mc_top] = 0;

+			return MDB_NOTFOUND;

+		}

+		if (mp->mp_flags & P_LEAF2) {

+			nodekey.mv_size = mc->mc_db->md_pad;

+			nodekey.mv_data = LEAF2KEY(mp, 0, nodekey.mv_size);

+		} else {

+			leaf = NODEPTR(mp, 0);

+			MDB_GET_KEY2(leaf, nodekey);

+		}

+		rc = mc->mc_dbx->md_cmp(key, &nodekey);

+		if (rc == 0) {

+			/* Probably happens rarely, but first node on the page

+			 * was the one we wanted.

+			 */

+			mc->mc_ki[mc->mc_top] = 0;

+			if (exactp)

+				*exactp = 1;

+			goto set1;

+		}

+		if (rc > 0) {

+			unsigned int i;

+			unsigned int nkeys = NUMKEYS(mp);

+			if (nkeys > 1) {

+				if (mp->mp_flags & P_LEAF2) {

+					nodekey.mv_data = LEAF2KEY(mp,

+						 nkeys-1, nodekey.mv_size);

+				} else {

+					leaf = NODEPTR(mp, nkeys-1);

+					MDB_GET_KEY2(leaf, nodekey);

+				}

+				rc = mc->mc_dbx->md_cmp(key, &nodekey);

+				if (rc == 0) {

+					/* last node was the one we wanted */

+					mc->mc_ki[mc->mc_top] = nkeys-1;

+					if (exactp)

+						*exactp = 1;

+					goto set1;

+				}

+				if (rc < 0) {

+					if (mc->mc_ki[mc->mc_top] < NUMKEYS(mp)) {

+						/* This is definitely the right page, skip search_page */

+						if (mp->mp_flags & P_LEAF2) {

+							nodekey.mv_data = LEAF2KEY(mp,

+								 mc->mc_ki[mc->mc_top], nodekey.mv_size);

+						} else {

+							leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);

+							MDB_GET_KEY2(leaf, nodekey);

+						}

+						rc = mc->mc_dbx->md_cmp(key, &nodekey);

+						if (rc == 0) {

+							/* current node was the one we wanted */

+							if (exactp)

+								*exactp = 1;

+							goto set1;

+						}

+					}

+					rc = 0;

+					goto set2;

+				}

+			}

+			/* If any parents have right-sibs, search.

+			 * Otherwise, there's nothing further.

+			 */

+			for (i=0; i<mc->mc_top; i++)

+				if (mc->mc_ki[i] <

+					NUMKEYS(mc->mc_pg[i])-1)

+					break;

+			if (i == mc->mc_top) {

+				/* There are no other pages */

+				mc->mc_ki[mc->mc_top] = nkeys;

+				return MDB_NOTFOUND;

+			}

+		}

+		if (!mc->mc_top) {

+			/* There are no other pages */

+			mc->mc_ki[mc->mc_top] = 0;

+			if (op == MDB_SET_RANGE && !exactp) {

+				rc = 0;

+				goto set1;

+			} else

+				return MDB_NOTFOUND;

+		}

+	} else {

+		mc->mc_pg[0] = 0;

+	}

+

+	rc = mdb_page_search(mc, key, 0);

+	if (rc != MDB_SUCCESS)

+		return rc;

+

+	mp = mc->mc_pg[mc->mc_top];

+	mdb_cassert(mc, IS_LEAF(mp));

+

+set2:

+	leaf = mdb_node_search(mc, key, exactp);

+	if (exactp != NULL && !*exactp) {

+		/* MDB_SET specified and not an exact match. */

+		return MDB_NOTFOUND;

+	}

+

+	if (leaf == NULL) {

+		DPUTS("===> inexact leaf not found, goto sibling");

+		if ((rc = mdb_cursor_sibling(mc, 1)) != MDB_SUCCESS) {

+			mc->mc_flags |= C_EOF;

+			return rc;		/* no entries matched */

+		}

+		mp = mc->mc_pg[mc->mc_top];

+		mdb_cassert(mc, IS_LEAF(mp));

+		leaf = NODEPTR(mp, 0);

+	}

+

+set1:

+	mc->mc_flags |= C_INITIALIZED;

+	mc->mc_flags &= ~C_EOF;

+

+	if (IS_LEAF2(mp)) {

+		if (op == MDB_SET_RANGE || op == MDB_SET_KEY) {

+			key->mv_size = mc->mc_db->md_pad;

+			key->mv_data = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], key->mv_size);

+		}

+		return MDB_SUCCESS;

+	}

+

+#ifdef MDB_VL32

+	if (mc->mc_xcursor && mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED) {

+		mdb_cursor_unref(&mc->mc_xcursor->mx_cursor);

+	}

+#endif

+	if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {

+		mdb_xcursor_init1(mc, leaf);

+	}

+	if (data) {

+		if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {

+			if (op == MDB_SET || op == MDB_SET_KEY || op == MDB_SET_RANGE) {

+				rc = mdb_cursor_first(&mc->mc_xcursor->mx_cursor, data, NULL);

+			} else {

+				int ex2, *ex2p;

+				if (op == MDB_GET_BOTH) {

+					ex2p = &ex2;

+					ex2 = 0;

+				} else {

+					ex2p = NULL;

+				}

+				rc = mdb_cursor_set(&mc->mc_xcursor->mx_cursor, data, NULL, MDB_SET_RANGE, ex2p);

+				if (rc != MDB_SUCCESS)

+					return rc;

+			}

+		} else if (op == MDB_GET_BOTH || op == MDB_GET_BOTH_RANGE) {

+			MDB_val olddata;

+			MDB_cmp_func *dcmp;

+			if ((rc = mdb_node_read(mc, leaf, &olddata)) != MDB_SUCCESS)

+				return rc;

+			dcmp = mc->mc_dbx->md_dcmp;

+#if UINT_MAX < SIZE_MAX || defined(MDB_VL32)

+			if (dcmp == mdb_cmp_int && olddata.mv_size == sizeof(mdb_size_t))

+				dcmp = mdb_cmp_clong;

+#endif

+			rc = dcmp(data, &olddata);

+			if (rc) {

+				if (op == MDB_GET_BOTH || rc > 0)

+					return MDB_NOTFOUND;

+				rc = 0;

+			}

+			*data = olddata;

+

+		} else {

+			if (mc->mc_xcursor)

+				mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);

+			if ((rc = mdb_node_read(mc, leaf, data)) != MDB_SUCCESS)

+				return rc;

+		}

+	}

+

+	/* The key already matches in all other cases */

+	if (op == MDB_SET_RANGE || op == MDB_SET_KEY)

+		MDB_GET_KEY(leaf, key);

+	DPRINTF(("==> cursor placed on key [%s]", DKEY(key)));

+

+	return rc;

+}

+

+/** Move the cursor to the first item in the database. */

+static int

+mdb_cursor_first(MDB_cursor *mc, MDB_val *key, MDB_val *data)

+{

+	int		 rc;

+	MDB_node	*leaf;

+

+	if (mc->mc_xcursor) {

+#ifdef MDB_VL32

+		if (mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED) {

+			mdb_cursor_unref(&mc->mc_xcursor->mx_cursor);

+		}

+#endif

+		mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);

+	}

+

+	if (!(mc->mc_flags & C_INITIALIZED) || mc->mc_top) {

+		rc = mdb_page_search(mc, NULL, MDB_PS_FIRST);

+		if (rc != MDB_SUCCESS)

+			return rc;

+	}

+	mdb_cassert(mc, IS_LEAF(mc->mc_pg[mc->mc_top]));

+

+	leaf = NODEPTR(mc->mc_pg[mc->mc_top], 0);

+	mc->mc_flags |= C_INITIALIZED;

+	mc->mc_flags &= ~C_EOF;

+

+	mc->mc_ki[mc->mc_top] = 0;

+

+	if (IS_LEAF2(mc->mc_pg[mc->mc_top])) {

+		key->mv_size = mc->mc_db->md_pad;

+		key->mv_data = LEAF2KEY(mc->mc_pg[mc->mc_top], 0, key->mv_size);

+		return MDB_SUCCESS;

+	}

+

+	if (data) {

+		if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {

+			mdb_xcursor_init1(mc, leaf);

+			rc = mdb_cursor_first(&mc->mc_xcursor->mx_cursor, data, NULL);

+			if (rc)

+				return rc;

+		} else {

+			if ((rc = mdb_node_read(mc, leaf, data)) != MDB_SUCCESS)

+				return rc;

+		}

+	}

+	MDB_GET_KEY(leaf, key);

+	return MDB_SUCCESS;

+}

+

+/** Move the cursor to the last item in the database. */

+static int

+mdb_cursor_last(MDB_cursor *mc, MDB_val *key, MDB_val *data)

+{

+	int		 rc;

+	MDB_node	*leaf;

+

+	if (mc->mc_xcursor) {

+#ifdef MDB_VL32

+		if (mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED) {

+			mdb_cursor_unref(&mc->mc_xcursor->mx_cursor);

+		}

+#endif

+		mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);

+	}

+

+	if (!(mc->mc_flags & C_EOF)) {

+

+		if (!(mc->mc_flags & C_INITIALIZED) || mc->mc_top) {

+			rc = mdb_page_search(mc, NULL, MDB_PS_LAST);

+			if (rc != MDB_SUCCESS)

+				return rc;

+		}

+		mdb_cassert(mc, IS_LEAF(mc->mc_pg[mc->mc_top]));

+

+	}

+	mc->mc_ki[mc->mc_top] = NUMKEYS(mc->mc_pg[mc->mc_top]) - 1;

+	mc->mc_flags |= C_INITIALIZED|C_EOF;

+	leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);

+

+	if (IS_LEAF2(mc->mc_pg[mc->mc_top])) {

+		key->mv_size = mc->mc_db->md_pad;

+		key->mv_data = LEAF2KEY(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top], key->mv_size);

+		return MDB_SUCCESS;

+	}

+

+	if (data) {

+		if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {

+			mdb_xcursor_init1(mc, leaf);

+			rc = mdb_cursor_last(&mc->mc_xcursor->mx_cursor, data, NULL);

+			if (rc)

+				return rc;

+		} else {

+			if ((rc = mdb_node_read(mc, leaf, data)) != MDB_SUCCESS)

+				return rc;

+		}

+	}

+

+	MDB_GET_KEY(leaf, key);

+	return MDB_SUCCESS;

+}

+

+int

+mdb_cursor_get(MDB_cursor *mc, MDB_val *key, MDB_val *data,

+    MDB_cursor_op op)

+{

+	int		 rc;

+	int		 exact = 0;

+	int		 (*mfunc)(MDB_cursor *mc, MDB_val *key, MDB_val *data);

+

+	if (mc == NULL)

+		return EINVAL;

+

+	if (mc->mc_txn->mt_flags & MDB_TXN_BLOCKED)

+		return MDB_BAD_TXN;

+

+	switch (op) {

+	case MDB_GET_CURRENT:

+		if (!(mc->mc_flags & C_INITIALIZED)) {

+			rc = EINVAL;

+		} else {

+			MDB_page *mp = mc->mc_pg[mc->mc_top];

+			int nkeys = NUMKEYS(mp);

+			if (!nkeys || mc->mc_ki[mc->mc_top] >= nkeys) {

+				mc->mc_ki[mc->mc_top] = nkeys;

+				rc = MDB_NOTFOUND;

+				break;

+			}

+			rc = MDB_SUCCESS;

+			if (IS_LEAF2(mp)) {

+				key->mv_size = mc->mc_db->md_pad;

+				key->mv_data = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], key->mv_size);

+			} else {

+				MDB_node *leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);

+				MDB_GET_KEY(leaf, key);

+				if (data) {

+					if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {

+						rc = mdb_cursor_get(&mc->mc_xcursor->mx_cursor, data, NULL, MDB_GET_CURRENT);

+					} else {

+						rc = mdb_node_read(mc, leaf, data);

+					}

+				}

+			}

+		}

+		break;

+	case MDB_GET_BOTH:

+	case MDB_GET_BOTH_RANGE:

+		if (data == NULL) {

+			rc = EINVAL;

+			break;

+		}

+		if (mc->mc_xcursor == NULL) {

+			rc = MDB_INCOMPATIBLE;

+			break;

+		}

+		/* FALLTHRU */

+	case MDB_SET:

+	case MDB_SET_KEY:

+	case MDB_SET_RANGE:

+		if (key == NULL) {

+			rc = EINVAL;

+		} else {

+			rc = mdb_cursor_set(mc, key, data, op,

+				op == MDB_SET_RANGE ? NULL : &exact);

+		}

+		break;

+	case MDB_GET_MULTIPLE:

+		if (data == NULL || !(mc->mc_flags & C_INITIALIZED)) {

+			rc = EINVAL;

+			break;

+		}

+		if (!(mc->mc_db->md_flags & MDB_DUPFIXED)) {

+			rc = MDB_INCOMPATIBLE;

+			break;

+		}

+		rc = MDB_SUCCESS;

+		if (!(mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED) ||

+			(mc->mc_xcursor->mx_cursor.mc_flags & C_EOF))

+			break;

+		goto fetchm;

+	case MDB_NEXT_MULTIPLE:

+		if (data == NULL) {

+			rc = EINVAL;

+			break;

+		}

+		if (!(mc->mc_db->md_flags & MDB_DUPFIXED)) {

+			rc = MDB_INCOMPATIBLE;

+			break;

+		}

+		rc = mdb_cursor_next(mc, key, data, MDB_NEXT_DUP);

+		if (rc == MDB_SUCCESS) {

+			if (mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED) {

+				MDB_cursor *mx;

+fetchm:

+				mx = &mc->mc_xcursor->mx_cursor;

+				data->mv_size = NUMKEYS(mx->mc_pg[mx->mc_top]) *

+					mx->mc_db->md_pad;

+				data->mv_data = METADATA(mx->mc_pg[mx->mc_top]);

+				mx->mc_ki[mx->mc_top] = NUMKEYS(mx->mc_pg[mx->mc_top])-1;

+			} else {

+				rc = MDB_NOTFOUND;

+			}

+		}

+		break;

+	case MDB_PREV_MULTIPLE:

+		if (data == NULL) {

+			rc = EINVAL;

+			break;

+		}

+		if (!(mc->mc_db->md_flags & MDB_DUPFIXED)) {

+			rc = MDB_INCOMPATIBLE;

+			break;

+		}

+		if (!(mc->mc_flags & C_INITIALIZED))

+			rc = mdb_cursor_last(mc, key, data);

+		else

+			rc = MDB_SUCCESS;

+		if (rc == MDB_SUCCESS) {

+			MDB_cursor *mx = &mc->mc_xcursor->mx_cursor;

+			if (mx->mc_flags & C_INITIALIZED) {

+				rc = mdb_cursor_sibling(mx, 0);

+				if (rc == MDB_SUCCESS)

+					goto fetchm;

+			} else {

+				rc = MDB_NOTFOUND;

+			}

+		}

+		break;

+	case MDB_NEXT:

+	case MDB_NEXT_DUP:

+	case MDB_NEXT_NODUP:

+		rc = mdb_cursor_next(mc, key, data, op);

+		break;

+	case MDB_PREV:

+	case MDB_PREV_DUP:

+	case MDB_PREV_NODUP:

+		rc = mdb_cursor_prev(mc, key, data, op);

+		break;

+	case MDB_FIRST:

+		rc = mdb_cursor_first(mc, key, data);

+		break;

+	case MDB_FIRST_DUP:

+		mfunc = mdb_cursor_first;

+	mmove:

+		if (data == NULL || !(mc->mc_flags & C_INITIALIZED)) {

+			rc = EINVAL;

+			break;

+		}

+		if (mc->mc_xcursor == NULL) {

+			rc = MDB_INCOMPATIBLE;

+			break;

+		}

+		{

+			MDB_node *leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);

+			if (!F_ISSET(leaf->mn_flags, F_DUPDATA)) {

+				MDB_GET_KEY(leaf, key);

+				rc = mdb_node_read(mc, leaf, data);

+				break;

+			}

+		}

+		if (!(mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED)) {

+			rc = EINVAL;

+			break;

+		}

+		rc = mfunc(&mc->mc_xcursor->mx_cursor, data, NULL);

+		break;

+	case MDB_LAST:

+		rc = mdb_cursor_last(mc, key, data);

+		break;

+	case MDB_LAST_DUP:

+		mfunc = mdb_cursor_last;

+		goto mmove;

+	default:

+		DPRINTF(("unhandled/unimplemented cursor operation %u", op));

+		rc = EINVAL;

+		break;

+	}

+

+	if (mc->mc_flags & C_DEL)

+		mc->mc_flags ^= C_DEL;

+

+	return rc;

+}

+

+/** Touch all the pages in the cursor stack. Set mc_top.

+ *	Makes sure all the pages are writable, before attempting a write operation.

+ * @param[in] mc The cursor to operate on.

+ */

+static int

+mdb_cursor_touch(MDB_cursor *mc)

+{

+	int rc = MDB_SUCCESS;

+

+	if (mc->mc_dbi >= CORE_DBS && !(*mc->mc_dbflag & DB_DIRTY)) {

+		MDB_cursor mc2;

+		MDB_xcursor mcx;

+		if (TXN_DBI_CHANGED(mc->mc_txn, mc->mc_dbi))

+			return MDB_BAD_DBI;

+		mdb_cursor_init(&mc2, mc->mc_txn, MAIN_DBI, &mcx);

+		rc = mdb_page_search(&mc2, &mc->mc_dbx->md_name, MDB_PS_MODIFY);

+		if (rc)

+			 return rc;

+		*mc->mc_dbflag |= DB_DIRTY;

+	}

+	mc->mc_top = 0;

+	if (mc->mc_snum) {

+		do {

+			rc = mdb_page_touch(mc);

+		} while (!rc && ++(mc->mc_top) < mc->mc_snum);

+		mc->mc_top = mc->mc_snum-1;

+	}

+	return rc;

+}

+

+/** Do not spill pages to disk if txn is getting full, may fail instead */

+#define MDB_NOSPILL	0x8000

+

+int

+mdb_cursor_put(MDB_cursor *mc, MDB_val *key, MDB_val *data,

+    unsigned int flags)

+{

+	MDB_env		*env;

+	MDB_node	*leaf = NULL;

+	MDB_page	*fp, *mp, *sub_root = NULL;

+	uint16_t	fp_flags;

+	MDB_val		xdata, *rdata, dkey, olddata;

+	MDB_db dummy;

+	int do_sub = 0, insert_key, insert_data;

+	unsigned int mcount = 0, dcount = 0, nospill;

+	size_t nsize;

+	int rc, rc2;

+	unsigned int nflags;

+	DKBUF;

+

+	if (mc == NULL || key == NULL)

+		return EINVAL;

+

+	env = mc->mc_txn->mt_env;

+

+	/* Check this first so counter will always be zero on any

+	 * early failures.

+	 */

+	if (flags & MDB_MULTIPLE) {

+		dcount = data[1].mv_size;

+		data[1].mv_size = 0;

+		if (!F_ISSET(mc->mc_db->md_flags, MDB_DUPFIXED))

+			return MDB_INCOMPATIBLE;

+	}

+

+	nospill = flags & MDB_NOSPILL;

+	flags &= ~MDB_NOSPILL;

+

+	if (mc->mc_txn->mt_flags & (MDB_TXN_RDONLY|MDB_TXN_BLOCKED))

+		return (mc->mc_txn->mt_flags & MDB_TXN_RDONLY) ? EACCES : MDB_BAD_TXN;

+

+	if (key->mv_size-1 >= ENV_MAXKEY(env))

+		return MDB_BAD_VALSIZE;

+

+#if SIZE_MAX > MAXDATASIZE

+	if (data->mv_size > ((mc->mc_db->md_flags & MDB_DUPSORT) ? ENV_MAXKEY(env) : MAXDATASIZE))

+		return MDB_BAD_VALSIZE;

+#else

+	if ((mc->mc_db->md_flags & MDB_DUPSORT) && data->mv_size > ENV_MAXKEY(env))

+		return MDB_BAD_VALSIZE;

+#endif

+

+	DPRINTF(("==> put db %d key [%s], size %"Z"u, data size %"Z"u",

+		DDBI(mc), DKEY(key), key ? key->mv_size : 0, data->mv_size));

+

+	dkey.mv_size = 0;

+

+	if (flags == MDB_CURRENT) {

+		if (!(mc->mc_flags & C_INITIALIZED))

+			return EINVAL;

+		rc = MDB_SUCCESS;

+	} else if (mc->mc_db->md_root == P_INVALID) {

+		/* new database, cursor has nothing to point to */

+		mc->mc_snum = 0;

+		mc->mc_top = 0;

+		mc->mc_flags &= ~C_INITIALIZED;

+		rc = MDB_NO_ROOT;

+	} else {

+		int exact = 0;

+		MDB_val d2;

+		if (flags & MDB_APPEND) {

+			MDB_val k2;

+			rc = mdb_cursor_last(mc, &k2, &d2);

+			if (rc == 0) {

+				rc = mc->mc_dbx->md_cmp(key, &k2);

+				if (rc > 0) {

+					rc = MDB_NOTFOUND;

+					mc->mc_ki[mc->mc_top]++;

+				} else {

+					/* new key is <= last key */

+					rc = MDB_KEYEXIST;

+				}

+			}

+		} else {

+			rc = mdb_cursor_set(mc, key, &d2, MDB_SET, &exact);

+		}

+		if ((flags & MDB_NOOVERWRITE) && rc == 0) {

+			DPRINTF(("duplicate key [%s]", DKEY(key)));

+			*data = d2;

+			return MDB_KEYEXIST;

+		}

+		if (rc && rc != MDB_NOTFOUND)

+			return rc;

+	}

+

+	if (mc->mc_flags & C_DEL)

+		mc->mc_flags ^= C_DEL;

+

+	/* Cursor is positioned, check for room in the dirty list */

+	if (!nospill) {

+		if (flags & MDB_MULTIPLE) {

+			rdata = &xdata;

+			xdata.mv_size = data->mv_size * dcount;

+		} else {

+			rdata = data;

+		}

+		if ((rc2 = mdb_page_spill(mc, key, rdata)))

+			return rc2;

+	}

+

+	if (rc == MDB_NO_ROOT) {

+		MDB_page *np;

+		/* new database, write a root leaf page */

+		DPUTS("allocating new root leaf page");

+		if ((rc2 = mdb_page_new(mc, P_LEAF, 1, &np))) {

+			return rc2;

+		}

+		mdb_cursor_push(mc, np);

+		mc->mc_db->md_root = np->mp_pgno;

+		mc->mc_db->md_depth++;

+		*mc->mc_dbflag |= DB_DIRTY;

+		if ((mc->mc_db->md_flags & (MDB_DUPSORT|MDB_DUPFIXED))

+			== MDB_DUPFIXED)

+			np->mp_flags |= P_LEAF2;

+		mc->mc_flags |= C_INITIALIZED;

+	} else {

+		/* make sure all cursor pages are writable */

+		rc2 = mdb_cursor_touch(mc);

+		if (rc2)

+			return rc2;

+	}

+

+	insert_key = insert_data = rc;

+	if (insert_key) {

+		/* The key does not exist */

+		DPRINTF(("inserting key at index %i", mc->mc_ki[mc->mc_top]));

+		if ((mc->mc_db->md_flags & MDB_DUPSORT) &&

+			LEAFSIZE(key, data) > env->me_nodemax)

+		{

+			/* Too big for a node, insert in sub-DB.  Set up an empty

+			 * "old sub-page" for prep_subDB to expand to a full page.

+			 */

+			fp_flags = P_LEAF|P_DIRTY;

+			fp = env->me_pbuf;

+			fp->mp_pad = data->mv_size; /* used if MDB_DUPFIXED */

+			fp->mp_lower = fp->mp_upper = (PAGEHDRSZ-PAGEBASE);

+			olddata.mv_size = PAGEHDRSZ;

+			goto prep_subDB;

+		}

+	} else {

+		/* there's only a key anyway, so this is a no-op */

+		if (IS_LEAF2(mc->mc_pg[mc->mc_top])) {

+			char *ptr;

+			unsigned int ksize = mc->mc_db->md_pad;

+			if (key->mv_size != ksize)

+				return MDB_BAD_VALSIZE;

+			ptr = LEAF2KEY(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top], ksize);

+			memcpy(ptr, key->mv_data, ksize);

+fix_parent:

+			/* if overwriting slot 0 of leaf, need to

+			 * update branch key if there is a parent page

+			 */

+			if (mc->mc_top && !mc->mc_ki[mc->mc_top]) {

+				unsigned short dtop = 1;

+				mc->mc_top--;

+				/* slot 0 is always an empty key, find real slot */

+				while (mc->mc_top && !mc->mc_ki[mc->mc_top]) {

+					mc->mc_top--;

+					dtop++;

+				}

+				if (mc->mc_ki[mc->mc_top])

+					rc2 = mdb_update_key(mc, key);

+				else

+					rc2 = MDB_SUCCESS;

+				mc->mc_top += dtop;

+				if (rc2)

+					return rc2;

+			}

+			return MDB_SUCCESS;

+		}

+

+more:

+		leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);

+		olddata.mv_size = NODEDSZ(leaf);

+		olddata.mv_data = NODEDATA(leaf);

+

+		/* DB has dups? */

+		if (F_ISSET(mc->mc_db->md_flags, MDB_DUPSORT)) {

+			/* Prepare (sub-)page/sub-DB to accept the new item,

+			 * if needed.  fp: old sub-page or a header faking

+			 * it.  mp: new (sub-)page.  offset: growth in page

+			 * size.  xdata: node data with new page or DB.

+			 */

+			unsigned	i, offset = 0;

+			mp = fp = xdata.mv_data = env->me_pbuf;

+			mp->mp_pgno = mc->mc_pg[mc->mc_top]->mp_pgno;

+

+			/* Was a single item before, must convert now */

+			if (!F_ISSET(leaf->mn_flags, F_DUPDATA)) {

+				MDB_cmp_func *dcmp;

+				/* Just overwrite the current item */

+				if (flags == MDB_CURRENT)

+					goto current;

+				dcmp = mc->mc_dbx->md_dcmp;

+#if UINT_MAX < SIZE_MAX || defined(MDB_VL32)

+				if (dcmp == mdb_cmp_int && olddata.mv_size == sizeof(mdb_size_t))

+					dcmp = mdb_cmp_clong;

+#endif

+				/* does data match? */

+				if (!dcmp(data, &olddata)) {

+					if (flags & (MDB_NODUPDATA|MDB_APPENDDUP))

+						return MDB_KEYEXIST;

+					/* overwrite it */

+					goto current;

+				}

+

+				/* Back up original data item */

+				dkey.mv_size = olddata.mv_size;

+				dkey.mv_data = memcpy(fp+1, olddata.mv_data, olddata.mv_size);

+

+				/* Make sub-page header for the dup items, with dummy body */

+				fp->mp_flags = P_LEAF|P_DIRTY|P_SUBP;

+				fp->mp_lower = (PAGEHDRSZ-PAGEBASE);

+				xdata.mv_size = PAGEHDRSZ + dkey.mv_size + data->mv_size;

+				if (mc->mc_db->md_flags & MDB_DUPFIXED) {

+					fp->mp_flags |= P_LEAF2;

+					fp->mp_pad = data->mv_size;

+					xdata.mv_size += 2 * data->mv_size;	/* leave space for 2 more */

+				} else {

+					xdata.mv_size += 2 * (sizeof(indx_t) + NODESIZE) +

+						(dkey.mv_size & 1) + (data->mv_size & 1);

+				}

+				fp->mp_upper = xdata.mv_size - PAGEBASE;

+				olddata.mv_size = xdata.mv_size; /* pretend olddata is fp */

+			} else if (leaf->mn_flags & F_SUBDATA) {

+				/* Data is on sub-DB, just store it */

+				flags |= F_DUPDATA|F_SUBDATA;

+				goto put_sub;

+			} else {

+				/* Data is on sub-page */

+				fp = olddata.mv_data;

+				switch (flags) {

+				default:

+					if (!(mc->mc_db->md_flags & MDB_DUPFIXED)) {

+						offset = EVEN(NODESIZE + sizeof(indx_t) +

+							data->mv_size);

+						break;

+					}

+					offset = fp->mp_pad;

+					if (SIZELEFT(fp) < offset) {

+						offset *= 4; /* space for 4 more */

+						break;

+					}

+					/* FALLTHRU: Big enough MDB_DUPFIXED sub-page */

+				case MDB_CURRENT:

+					fp->mp_flags |= P_DIRTY;

+					COPY_PGNO(fp->mp_pgno, mp->mp_pgno);

+					mc->mc_xcursor->mx_cursor.mc_pg[0] = fp;

+					flags |= F_DUPDATA;

+					goto put_sub;

+				}

+				xdata.mv_size = olddata.mv_size + offset;

+			}

+

+			fp_flags = fp->mp_flags;

+			if (NODESIZE + NODEKSZ(leaf) + xdata.mv_size > env->me_nodemax) {

+					/* Too big for a sub-page, convert to sub-DB */

+					fp_flags &= ~P_SUBP;

+prep_subDB:

+					if (mc->mc_db->md_flags & MDB_DUPFIXED) {

+						fp_flags |= P_LEAF2;

+						dummy.md_pad = fp->mp_pad;

+						dummy.md_flags = MDB_DUPFIXED;

+						if (mc->mc_db->md_flags & MDB_INTEGERDUP)

+							dummy.md_flags |= MDB_INTEGERKEY;

+					} else {

+						dummy.md_pad = 0;

+						dummy.md_flags = 0;

+					}

+					dummy.md_depth = 1;

+					dummy.md_branch_pages = 0;

+					dummy.md_leaf_pages = 1;

+					dummy.md_overflow_pages = 0;

+					dummy.md_entries = NUMKEYS(fp);

+					xdata.mv_size = sizeof(MDB_db);

+					xdata.mv_data = &dummy;

+					if ((rc = mdb_page_alloc(mc, 1, &mp)))

+						return rc;

+					offset = env->me_psize - olddata.mv_size;

+					flags |= F_DUPDATA|F_SUBDATA;

+					dummy.md_root = mp->mp_pgno;

+					sub_root = mp;

+			}

+			if (mp != fp) {

+				mp->mp_flags = fp_flags | P_DIRTY;

+				mp->mp_pad   = fp->mp_pad;

+				mp->mp_lower = fp->mp_lower;

+				mp->mp_upper = fp->mp_upper + offset;

+				if (fp_flags & P_LEAF2) {

+					memcpy(METADATA(mp), METADATA(fp), NUMKEYS(fp) * fp->mp_pad);

+				} else {

+					memcpy((char *)mp + mp->mp_upper + PAGEBASE, (char *)fp + fp->mp_upper + PAGEBASE,

+						olddata.mv_size - fp->mp_upper - PAGEBASE);

+					for (i=0; i<NUMKEYS(fp); i++)

+						mp->mp_ptrs[i] = fp->mp_ptrs[i] + offset;

+				}

+			}

+

+			rdata = &xdata;

+			flags |= F_DUPDATA;

+			do_sub = 1;

+			if (!insert_key)

+				mdb_node_del(mc, 0);

+			goto new_sub;

+		}

+current:

+		/* LMDB passes F_SUBDATA in 'flags' to write a DB record */

+		if ((leaf->mn_flags ^ flags) & F_SUBDATA)

+			return MDB_INCOMPATIBLE;

+		/* overflow page overwrites need special handling */

+		if (F_ISSET(leaf->mn_flags, F_BIGDATA)) {

+			MDB_page *omp;

+			pgno_t pg;

+			int level, ovpages, dpages = OVPAGES(data->mv_size, env->me_psize);

+

+			memcpy(&pg, olddata.mv_data, sizeof(pg));

+			if ((rc2 = mdb_page_get(mc, pg, &omp, &level)) != 0)

+				return rc2;

+			ovpages = omp->mp_pages;

+

+			/* Is the ov page large enough? */

+			if (ovpages >= dpages) {

+			  if (!(omp->mp_flags & P_DIRTY) &&

+				  (level || (env->me_flags & MDB_WRITEMAP)))

+			  {

+				rc = mdb_page_unspill(mc->mc_txn, omp, &omp);

+				if (rc)

+					return rc;

+				level = 0;		/* dirty in this txn or clean */

+			  }

+			  /* Is it dirty? */

+			  if (omp->mp_flags & P_DIRTY) {

+				/* yes, overwrite it. Note in this case we don't

+				 * bother to try shrinking the page if the new data

+				 * is smaller than the overflow threshold.

+				 */

+				if (level > 1) {

+					/* It is writable only in a parent txn */

+					size_t sz = (size_t) env->me_psize * ovpages, off;

+					MDB_page *np = mdb_page_malloc(mc->mc_txn, ovpages);

+					MDB_ID2 id2;

+					if (!np)

+						return ENOMEM;

+					id2.mid = pg;

+					id2.mptr = np;

+					/* Note - this page is already counted in parent's dirty_room */

+					rc2 = mdb_mid2l_insert(mc->mc_txn->mt_u.dirty_list, &id2);

+					mdb_cassert(mc, rc2 == 0);

+					if (!(flags & MDB_RESERVE)) {

+						/* Copy end of page, adjusting alignment so

+						 * compiler may copy words instead of bytes.

+						 */

+						off = (PAGEHDRSZ + data->mv_size) & -sizeof(size_t);

+						memcpy((size_t *)((char *)np + off),

+							(size_t *)((char *)omp + off), sz - off);

+						sz = PAGEHDRSZ;

+					}

+					memcpy(np, omp, sz); /* Copy beginning of page */

+					omp = np;

+				}

+				SETDSZ(leaf, data->mv_size);

+				if (F_ISSET(flags, MDB_RESERVE))

+					data->mv_data = METADATA(omp);

+				else

+					memcpy(METADATA(omp), data->mv_data, data->mv_size);

+				return MDB_SUCCESS;

+			  }

+			}

+			if ((rc2 = mdb_ovpage_free(mc, omp)) != MDB_SUCCESS)

+				return rc2;

+		} else if (data->mv_size == olddata.mv_size) {

+			/* same size, just replace it. Note that we could

+			 * also reuse this node if the new data is smaller,

+			 * but instead we opt to shrink the node in that case.

+			 */

+			if (F_ISSET(flags, MDB_RESERVE))

+				data->mv_data = olddata.mv_data;

+			else if (!(mc->mc_flags & C_SUB))

+				memcpy(olddata.mv_data, data->mv_data, data->mv_size);

+			else {

+				memcpy(NODEKEY(leaf), key->mv_data, key->mv_size);

+				goto fix_parent;

+			}

+			return MDB_SUCCESS;

+		}

+		mdb_node_del(mc, 0);

+	}

+

+	rdata = data;

+

+new_sub:

+	nflags = flags & NODE_ADD_FLAGS;

+	nsize = IS_LEAF2(mc->mc_pg[mc->mc_top]) ? key->mv_size : mdb_leaf_size(env, key, rdata);

+	if (SIZELEFT(mc->mc_pg[mc->mc_top]) < nsize) {

+		if (( flags & (F_DUPDATA|F_SUBDATA)) == F_DUPDATA )

+			nflags &= ~MDB_APPEND; /* sub-page may need room to grow */

+		if (!insert_key)

+			nflags |= MDB_SPLIT_REPLACE;

+		rc = mdb_page_split(mc, key, rdata, P_INVALID, nflags);

+	} else {

+		/* There is room already in this leaf page. */

+		rc = mdb_node_add(mc, mc->mc_ki[mc->mc_top], key, rdata, 0, nflags);

+		if (rc == 0) {

+			/* Adjust other cursors pointing to mp */

+			MDB_cursor *m2, *m3;

+			MDB_dbi dbi = mc->mc_dbi;

+			unsigned i = mc->mc_top;

+			MDB_page *mp = mc->mc_pg[i];

+

+			for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {

+				if (mc->mc_flags & C_SUB)

+					m3 = &m2->mc_xcursor->mx_cursor;

+				else

+					m3 = m2;

+				if (m3 == mc || m3->mc_snum < mc->mc_snum || m3->mc_pg[i] != mp) continue;

+				if (m3->mc_ki[i] >= mc->mc_ki[i] && insert_key) {

+					m3->mc_ki[i]++;

+				}

+				if (m3->mc_xcursor && (m3->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED)) {

+					MDB_node *n2 = NODEPTR(mp, m3->mc_ki[i]);

+					if ((n2->mn_flags & (F_SUBDATA|F_DUPDATA)) == F_DUPDATA)

+						m3->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(n2);

+				}

+			}

+		}

+	}

+

+	if (rc == MDB_SUCCESS) {

+		/* Now store the actual data in the child DB. Note that we're

+		 * storing the user data in the keys field, so there are strict

+		 * size limits on dupdata. The actual data fields of the child

+		 * DB are all zero size.

+		 */

+		if (do_sub) {

+			int xflags, new_dupdata;

+			mdb_size_t ecount;

+put_sub:

+			xdata.mv_size = 0;

+			xdata.mv_data = "";

+			leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);

+			if (flags & MDB_CURRENT) {

+				xflags = MDB_CURRENT|MDB_NOSPILL;

+			} else {

+				mdb_xcursor_init1(mc, leaf);

+				xflags = (flags & MDB_NODUPDATA) ?

+					MDB_NOOVERWRITE|MDB_NOSPILL : MDB_NOSPILL;

+			}

+			if (sub_root)

+				mc->mc_xcursor->mx_cursor.mc_pg[0] = sub_root;

+			new_dupdata = (int)dkey.mv_size;

+			/* converted, write the original data first */

+			if (dkey.mv_size) {

+				rc = mdb_cursor_put(&mc->mc_xcursor->mx_cursor, &dkey, &xdata, xflags);

+				if (rc)

+					goto bad_sub;

+				/* we've done our job */

+				dkey.mv_size = 0;

+			}

+			if (!(leaf->mn_flags & F_SUBDATA) || sub_root) {

+				/* Adjust other cursors pointing to mp */

+				MDB_cursor *m2;

+				MDB_xcursor *mx = mc->mc_xcursor;

+				unsigned i = mc->mc_top;

+				MDB_page *mp = mc->mc_pg[i];

+				int nkeys = NUMKEYS(mp);

+

+				for (m2 = mc->mc_txn->mt_cursors[mc->mc_dbi]; m2; m2=m2->mc_next) {

+					if (m2 == mc || m2->mc_snum < mc->mc_snum) continue;

+					if (!(m2->mc_flags & C_INITIALIZED)) continue;

+					if (m2->mc_pg[i] == mp) {

+						if (m2->mc_ki[i] == mc->mc_ki[i]) {

+							mdb_xcursor_init2(m2, mx, new_dupdata);

+						} else if (!insert_key && m2->mc_ki[i] < nkeys) {

+							MDB_node *n2 = NODEPTR(mp, m2->mc_ki[i]);

+							if ((n2->mn_flags & (F_SUBDATA|F_DUPDATA)) == F_DUPDATA)

+								m2->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(n2);

+						}

+					}

+				}

+			}

+			ecount = mc->mc_xcursor->mx_db.md_entries;

+			if (flags & MDB_APPENDDUP)

+				xflags |= MDB_APPEND;

+			rc = mdb_cursor_put(&mc->mc_xcursor->mx_cursor, data, &xdata, xflags);

+			if (flags & F_SUBDATA) {

+				void *db = NODEDATA(leaf);

+				memcpy(db, &mc->mc_xcursor->mx_db, sizeof(MDB_db));

+			}

+			insert_data = mc->mc_xcursor->mx_db.md_entries - ecount;

+		}

+		/* Increment count unless we just replaced an existing item. */

+		if (insert_data)

+			mc->mc_db->md_entries++;

+		if (insert_key) {

+			/* Invalidate txn if we created an empty sub-DB */

+			if (rc)

+				goto bad_sub;

+			/* If we succeeded and the key didn't exist before,

+			 * make sure the cursor is marked valid.

+			 */

+			mc->mc_flags |= C_INITIALIZED;

+		}

+		if (flags & MDB_MULTIPLE) {

+			if (!rc) {

+				mcount++;

+				/* let caller know how many succeeded, if any */

+				data[1].mv_size = mcount;

+				if (mcount < dcount) {

+					data[0].mv_data = (char *)data[0].mv_data + data[0].mv_size;

+					insert_key = insert_data = 0;

+					goto more;

+				}

+			}

+		}

+		return rc;

+bad_sub:

+		if (rc == MDB_KEYEXIST)	/* should not happen, we deleted that item */

+			rc = MDB_CORRUPTED;

+	}

+	mc->mc_txn->mt_flags |= MDB_TXN_ERROR;

+	return rc;

+}

+

+int

+mdb_cursor_del(MDB_cursor *mc, unsigned int flags)

+{

+	MDB_node	*leaf;

+	MDB_page	*mp;

+	int rc;

+

+	if (mc->mc_txn->mt_flags & (MDB_TXN_RDONLY|MDB_TXN_BLOCKED))

+		return (mc->mc_txn->mt_flags & MDB_TXN_RDONLY) ? EACCES : MDB_BAD_TXN;

+

+	if (!(mc->mc_flags & C_INITIALIZED))

+		return EINVAL;

+

+	if (mc->mc_ki[mc->mc_top] >= NUMKEYS(mc->mc_pg[mc->mc_top]))

+		return MDB_NOTFOUND;

+

+	if (!(flags & MDB_NOSPILL) && (rc = mdb_page_spill(mc, NULL, NULL)))

+		return rc;

+

+	rc = mdb_cursor_touch(mc);

+	if (rc)

+		return rc;

+

+	mp = mc->mc_pg[mc->mc_top];

+	if (IS_LEAF2(mp))

+		goto del_key;

+	leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);

+

+	if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {

+		if (flags & MDB_NODUPDATA) {

+			/* mdb_cursor_del0() will subtract the final entry */

+			mc->mc_db->md_entries -= mc->mc_xcursor->mx_db.md_entries - 1;

+			mc->mc_xcursor->mx_cursor.mc_flags &= ~C_INITIALIZED;

+		} else {

+			if (!F_ISSET(leaf->mn_flags, F_SUBDATA)) {

+				mc->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(leaf);

+			}

+			rc = mdb_cursor_del(&mc->mc_xcursor->mx_cursor, MDB_NOSPILL);

+			if (rc)

+				return rc;

+			/* If sub-DB still has entries, we're done */

+			if (mc->mc_xcursor->mx_db.md_entries) {

+				if (leaf->mn_flags & F_SUBDATA) {

+					/* update subDB info */

+					void *db = NODEDATA(leaf);

+					memcpy(db, &mc->mc_xcursor->mx_db, sizeof(MDB_db));

+				} else {

+					MDB_cursor *m2;

+					/* shrink fake page */

+					mdb_node_shrink(mp, mc->mc_ki[mc->mc_top]);

+					leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);

+					mc->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(leaf);

+					/* fix other sub-DB cursors pointed at fake pages on this page */

+					for (m2 = mc->mc_txn->mt_cursors[mc->mc_dbi]; m2; m2=m2->mc_next) {

+						if (m2 == mc || m2->mc_snum < mc->mc_snum) continue;

+						if (!(m2->mc_flags & C_INITIALIZED)) continue;

+						if (m2->mc_pg[mc->mc_top] == mp) {

+							if (m2->mc_ki[mc->mc_top] == mc->mc_ki[mc->mc_top]) {

+								m2->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(leaf);

+							} else {

+								MDB_node *n2 = NODEPTR(mp, m2->mc_ki[mc->mc_top]);

+								if (!(n2->mn_flags & F_SUBDATA))

+									m2->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(n2);

+							}

+						}

+					}

+				}

+				mc->mc_db->md_entries--;

+				return rc;

+			} else {

+				mc->mc_xcursor->mx_cursor.mc_flags &= ~C_INITIALIZED;

+			}

+			/* otherwise fall thru and delete the sub-DB */

+		}

+

+		if (leaf->mn_flags & F_SUBDATA) {

+			/* add all the child DB's pages to the free list */

+			rc = mdb_drop0(&mc->mc_xcursor->mx_cursor, 0);

+			if (rc)

+				goto fail;

+		}

+	}

+	/* LMDB passes F_SUBDATA in 'flags' to delete a DB record */

+	else if ((leaf->mn_flags ^ flags) & F_SUBDATA) {

+		rc = MDB_INCOMPATIBLE;

+		goto fail;

+	}

+

+	/* add overflow pages to free list */

+	if (F_ISSET(leaf->mn_flags, F_BIGDATA)) {

+		MDB_page *omp;

+		pgno_t pg;

+

+		memcpy(&pg, NODEDATA(leaf), sizeof(pg));

+		if ((rc = mdb_page_get(mc, pg, &omp, NULL)) ||

+			(rc = mdb_ovpage_free(mc, omp)))

+			goto fail;

+	}

+

+del_key:

+	return mdb_cursor_del0(mc);

+

+fail:

+	mc->mc_txn->mt_flags |= MDB_TXN_ERROR;

+	return rc;

+}

+

+/** Allocate and initialize new pages for a database.

+ * @param[in] mc a cursor on the database being added to.

+ * @param[in] flags flags defining what type of page is being allocated.

+ * @param[in] num the number of pages to allocate. This is usually 1,

+ * unless allocating overflow pages for a large record.

+ * @param[out] mp Address of a page, or NULL on failure.

+ * @return 0 on success, non-zero on failure.

+ */

+static int

+mdb_page_new(MDB_cursor *mc, uint32_t flags, int num, MDB_page **mp)

+{

+	MDB_page	*np;

+	int rc;

+

+	if ((rc = mdb_page_alloc(mc, num, &np)))

+		return rc;

+	DPRINTF(("allocated new mpage %"Y"u, page size %u",

+	    np->mp_pgno, mc->mc_txn->mt_env->me_psize));

+	np->mp_flags = flags | P_DIRTY;

+	np->mp_lower = (PAGEHDRSZ-PAGEBASE);

+	np->mp_upper = mc->mc_txn->mt_env->me_psize - PAGEBASE;

+

+	if (IS_BRANCH(np))

+		mc->mc_db->md_branch_pages++;

+	else if (IS_LEAF(np))

+		mc->mc_db->md_leaf_pages++;

+	else if (IS_OVERFLOW(np)) {

+		mc->mc_db->md_overflow_pages += num;

+		np->mp_pages = num;

+	}

+	*mp = np;

+

+	return 0;

+}

+

+/** Calculate the size of a leaf node.

+ * The size depends on the environment's page size; if a data item

+ * is too large it will be put onto an overflow page and the node

+ * size will only include the key and not the data. Sizes are always

+ * rounded up to an even number of bytes, to guarantee 2-byte alignment

+ * of the #MDB_node headers.

+ * @param[in] env The environment handle.

+ * @param[in] key The key for the node.

+ * @param[in] data The data for the node.

+ * @return The number of bytes needed to store the node.

+ */

+static size_t

+mdb_leaf_size(MDB_env *env, MDB_val *key, MDB_val *data)

+{

+	size_t		 sz;

+

+	sz = LEAFSIZE(key, data);

+	if (sz > env->me_nodemax) {

+		/* put on overflow page */

+		sz -= data->mv_size - sizeof(pgno_t);

+	}

+

+	return EVEN(sz + sizeof(indx_t));

+}

+

+/** Calculate the size of a branch node.

+ * The size should depend on the environment's page size but since

+ * we currently don't support spilling large keys onto overflow

+ * pages, it's simply the size of the #MDB_node header plus the

+ * size of the key. Sizes are always rounded up to an even number

+ * of bytes, to guarantee 2-byte alignment of the #MDB_node headers.

+ * @param[in] env The environment handle.

+ * @param[in] key The key for the node.

+ * @return The number of bytes needed to store the node.

+ */

+static size_t

+mdb_branch_size(MDB_env *env, MDB_val *key)

+{

+	size_t		 sz;

+

+	sz = INDXSIZE(key);

+	if (sz > env->me_nodemax) {

+		/* put on overflow page */

+		/* not implemented */

+		/* sz -= key->size - sizeof(pgno_t); */

+	}

+

+	return sz + sizeof(indx_t);

+}

+

+/** Add a node to the page pointed to by the cursor.

+ * @param[in] mc The cursor for this operation.

+ * @param[in] indx The index on the page where the new node should be added.

+ * @param[in] key The key for the new node.

+ * @param[in] data The data for the new node, if any.

+ * @param[in] pgno The page number, if adding a branch node.

+ * @param[in] flags Flags for the node.

+ * @return 0 on success, non-zero on failure. Possible errors are:

+ * <ul>

+ *	<li>ENOMEM - failed to allocate overflow pages for the node.

+ *	<li>MDB_PAGE_FULL - there is insufficient room in the page. This error

+ *	should never happen since all callers already calculate the

+ *	page's free space before calling this function.

+ * </ul>

+ */

+static int

+mdb_node_add(MDB_cursor *mc, indx_t indx,

+    MDB_val *key, MDB_val *data, pgno_t pgno, unsigned int flags)

+{

+	unsigned int	 i;

+	size_t		 node_size = NODESIZE;

+	ssize_t		 room;

+	indx_t		 ofs;

+	MDB_node	*node;

+	MDB_page	*mp = mc->mc_pg[mc->mc_top];

+	MDB_page	*ofp = NULL;		/* overflow page */

+	void		*ndata;

+	DKBUF;

+

+	mdb_cassert(mc, mp->mp_upper >= mp->mp_lower);

+

+	DPRINTF(("add to %s %spage %"Y"u index %i, data size %"Z"u key size %"Z"u [%s]",

+	    IS_LEAF(mp) ? "leaf" : "branch",

+		IS_SUBP(mp) ? "sub-" : "",

+		mdb_dbg_pgno(mp), indx, data ? data->mv_size : 0,

+		key ? key->mv_size : 0, key ? DKEY(key) : "null"));

+

+	if (IS_LEAF2(mp)) {

+		/* Move higher keys up one slot. */

+		int ksize = mc->mc_db->md_pad, dif;

+		char *ptr = LEAF2KEY(mp, indx, ksize);

+		dif = NUMKEYS(mp) - indx;

+		if (dif > 0)

+			memmove(ptr+ksize, ptr, dif*ksize);

+		/* insert new key */

+		memcpy(ptr, key->mv_data, ksize);

+

+		/* Just using these for counting */

+		mp->mp_lower += sizeof(indx_t);

+		mp->mp_upper -= ksize - sizeof(indx_t);

+		return MDB_SUCCESS;

+	}

+

+	room = (ssize_t)SIZELEFT(mp) - (ssize_t)sizeof(indx_t);

+	if (key != NULL)

+		node_size += key->mv_size;

+	if (IS_LEAF(mp)) {

+		mdb_cassert(mc, key && data);

+		if (F_ISSET(flags, F_BIGDATA)) {

+			/* Data already on overflow page. */

+			node_size += sizeof(pgno_t);

+		} else if (node_size + data->mv_size > mc->mc_txn->mt_env->me_nodemax) {

+			int ovpages = OVPAGES(data->mv_size, mc->mc_txn->mt_env->me_psize);

+			int rc;

+			/* Put data on overflow page. */

+			DPRINTF(("data size is %"Z"u, node would be %"Z"u, put data on overflow page",

+			    data->mv_size, node_size+data->mv_size));

+			node_size = EVEN(node_size + sizeof(pgno_t));

+			if ((ssize_t)node_size > room)

+				goto full;

+			if ((rc = mdb_page_new(mc, P_OVERFLOW, ovpages, &ofp)))

+				return rc;

+			DPRINTF(("allocated overflow page %"Y"u", ofp->mp_pgno));

+			flags |= F_BIGDATA;

+			goto update;

+		} else {

+			node_size += data->mv_size;

+		}

+	}

+	node_size = EVEN(node_size);

+	if ((ssize_t)node_size > room)

+		goto full;

+

+update:

+	/* Move higher pointers up one slot. */

+	for (i = NUMKEYS(mp); i > indx; i--)

+		mp->mp_ptrs[i] = mp->mp_ptrs[i - 1];

+

+	/* Adjust free space offsets. */

+	ofs = mp->mp_upper - node_size;

+	mdb_cassert(mc, ofs >= mp->mp_lower + sizeof(indx_t));

+	mp->mp_ptrs[indx] = ofs;

+	mp->mp_upper = ofs;

+	mp->mp_lower += sizeof(indx_t);

+

+	/* Write the node data. */

+	node = NODEPTR(mp, indx);

+	node->mn_ksize = (key == NULL) ? 0 : key->mv_size;

+	node->mn_flags = flags;

+	if (IS_LEAF(mp))

+		SETDSZ(node,data->mv_size);

+	else

+		SETPGNO(node,pgno);

+

+	if (key)

+		memcpy(NODEKEY(node), key->mv_data, key->mv_size);

+

+	if (IS_LEAF(mp)) {

+		ndata = NODEDATA(node);

+		if (ofp == NULL) {

+			if (F_ISSET(flags, F_BIGDATA))

+				memcpy(ndata, data->mv_data, sizeof(pgno_t));

+			else if (F_ISSET(flags, MDB_RESERVE))

+				data->mv_data = ndata;

+			else

+				memcpy(ndata, data->mv_data, data->mv_size);

+		} else {

+			memcpy(ndata, &ofp->mp_pgno, sizeof(pgno_t));

+			ndata = METADATA(ofp);

+			if (F_ISSET(flags, MDB_RESERVE))

+				data->mv_data = ndata;

+			else

+				memcpy(ndata, data->mv_data, data->mv_size);

+		}

+	}

+

+	return MDB_SUCCESS;

+

+full:

+	DPRINTF(("not enough room in page %"Y"u, got %u ptrs",

+		mdb_dbg_pgno(mp), NUMKEYS(mp)));

+	DPRINTF(("upper-lower = %u - %u = %"Z"d", mp->mp_upper,mp->mp_lower,room));

+	DPRINTF(("node size = %"Z"u", node_size));

+	mc->mc_txn->mt_flags |= MDB_TXN_ERROR;

+	return MDB_PAGE_FULL;

+}

+

+/** Delete the specified node from a page.

+ * @param[in] mc Cursor pointing to the node to delete.

+ * @param[in] ksize The size of a node. Only used if the page is

+ * part of a #MDB_DUPFIXED database.

+ */

+static void

+mdb_node_del(MDB_cursor *mc, int ksize)

+{

+	MDB_page *mp = mc->mc_pg[mc->mc_top];

+	indx_t	indx = mc->mc_ki[mc->mc_top];

+	unsigned int	 sz;

+	indx_t		 i, j, numkeys, ptr;

+	MDB_node	*node;

+	char		*base;

+

+	DPRINTF(("delete node %u on %s page %"Y"u", indx,

+	    IS_LEAF(mp) ? "leaf" : "branch", mdb_dbg_pgno(mp)));

+	numkeys = NUMKEYS(mp);

+	mdb_cassert(mc, indx < numkeys);

+

+	if (IS_LEAF2(mp)) {

+		int x = numkeys - 1 - indx;

+		base = LEAF2KEY(mp, indx, ksize);

+		if (x)

+			memmove(base, base + ksize, x * ksize);

+		mp->mp_lower -= sizeof(indx_t);

+		mp->mp_upper += ksize - sizeof(indx_t);

+		return;

+	}

+

+	node = NODEPTR(mp, indx);

+	sz = NODESIZE + node->mn_ksize;

+	if (IS_LEAF(mp)) {

+		if (F_ISSET(node->mn_flags, F_BIGDATA))

+			sz += sizeof(pgno_t);

+		else

+			sz += NODEDSZ(node);

+	}

+	sz = EVEN(sz);

+

+	ptr = mp->mp_ptrs[indx];

+	for (i = j = 0; i < numkeys; i++) {

+		if (i != indx) {

+			mp->mp_ptrs[j] = mp->mp_ptrs[i];

+			if (mp->mp_ptrs[i] < ptr)

+				mp->mp_ptrs[j] += sz;

+			j++;

+		}

+	}

+

+	base = (char *)mp + mp->mp_upper + PAGEBASE;

+	memmove(base + sz, base, ptr - mp->mp_upper);

+

+	mp->mp_lower -= sizeof(indx_t);

+	mp->mp_upper += sz;

+}

+

+/** Compact the main page after deleting a node on a subpage.

+ * @param[in] mp The main page to operate on.

+ * @param[in] indx The index of the subpage on the main page.

+ */

+static void

+mdb_node_shrink(MDB_page *mp, indx_t indx)

+{

+	MDB_node *node;

+	MDB_page *sp, *xp;

+	char *base;

+	indx_t delta, nsize, len, ptr;

+	int i;

+

+	node = NODEPTR(mp, indx);

+	sp = (MDB_page *)NODEDATA(node);

+	delta = SIZELEFT(sp);

+	nsize = NODEDSZ(node) - delta;

+

+	/* Prepare to shift upward, set len = length(subpage part to shift) */

+	if (IS_LEAF2(sp)) {

+		len = nsize;

+		if (nsize & 1)

+			return;		/* do not make the node uneven-sized */

+	} else {

+		xp = (MDB_page *)((char *)sp + delta); /* destination subpage */

+		for (i = NUMKEYS(sp); --i >= 0; )

+			xp->mp_ptrs[i] = sp->mp_ptrs[i] - delta;

+		len = PAGEHDRSZ;

+	}

+	sp->mp_upper = sp->mp_lower;

+	COPY_PGNO(sp->mp_pgno, mp->mp_pgno);

+	SETDSZ(node, nsize);

+

+	/* Shift <lower nodes...initial part of subpage> upward */

+	base = (char *)mp + mp->mp_upper + PAGEBASE;

+	memmove(base + delta, base, (char *)sp + len - base);

+

+	ptr = mp->mp_ptrs[indx];

+	for (i = NUMKEYS(mp); --i >= 0; ) {

+		if (mp->mp_ptrs[i] <= ptr)

+			mp->mp_ptrs[i] += delta;

+	}

+	mp->mp_upper += delta;

+}

+

+/** Initial setup of a sorted-dups cursor.

+ * Sorted duplicates are implemented as a sub-database for the given key.

+ * The duplicate data items are actually keys of the sub-database.

+ * Operations on the duplicate data items are performed using a sub-cursor

+ * initialized when the sub-database is first accessed. This function does

+ * the preliminary setup of the sub-cursor, filling in the fields that

+ * depend only on the parent DB.

+ * @param[in] mc The main cursor whose sorted-dups cursor is to be initialized.

+ */

+static void

+mdb_xcursor_init0(MDB_cursor *mc)

+{

+	MDB_xcursor *mx = mc->mc_xcursor;

+

+	mx->mx_cursor.mc_xcursor = NULL;

+	mx->mx_cursor.mc_txn = mc->mc_txn;

+	mx->mx_cursor.mc_db = &mx->mx_db;

+	mx->mx_cursor.mc_dbx = &mx->mx_dbx;

+	mx->mx_cursor.mc_dbi = mc->mc_dbi;

+	mx->mx_cursor.mc_dbflag = &mx->mx_dbflag;

+	mx->mx_cursor.mc_snum = 0;

+	mx->mx_cursor.mc_top = 0;

+#ifdef MDB_VL32

+	mx->mx_cursor.mc_ovpg = 0;

+#endif

+	mx->mx_cursor.mc_flags = C_SUB | (mc->mc_flags & (C_ORIG_RDONLY|C_WRITEMAP));

+	mx->mx_dbx.md_name.mv_size = 0;

+	mx->mx_dbx.md_name.mv_data = NULL;

+	mx->mx_dbx.md_cmp = mc->mc_dbx->md_dcmp;

+	mx->mx_dbx.md_dcmp = NULL;

+	mx->mx_dbx.md_rel = mc->mc_dbx->md_rel;

+}

+

+/** Final setup of a sorted-dups cursor.

+ *	Sets up the fields that depend on the data from the main cursor.

+ * @param[in] mc The main cursor whose sorted-dups cursor is to be initialized.

+ * @param[in] node The data containing the #MDB_db record for the

+ * sorted-dup database.

+ */

+static void

+mdb_xcursor_init1(MDB_cursor *mc, MDB_node *node)

+{

+	MDB_xcursor *mx = mc->mc_xcursor;

+

+	mx->mx_cursor.mc_flags &= C_SUB|C_ORIG_RDONLY|C_WRITEMAP;

+	if (node->mn_flags & F_SUBDATA) {

+		memcpy(&mx->mx_db, NODEDATA(node), sizeof(MDB_db));

+		mx->mx_cursor.mc_pg[0] = 0;

+		mx->mx_cursor.mc_snum = 0;

+		mx->mx_cursor.mc_top = 0;

+	} else {

+		MDB_page *fp = NODEDATA(node);

+		mx->mx_db.md_pad = 0;

+		mx->mx_db.md_flags = 0;

+		mx->mx_db.md_depth = 1;

+		mx->mx_db.md_branch_pages = 0;

+		mx->mx_db.md_leaf_pages = 1;

+		mx->mx_db.md_overflow_pages = 0;

+		mx->mx_db.md_entries = NUMKEYS(fp);

+		COPY_PGNO(mx->mx_db.md_root, fp->mp_pgno);

+		mx->mx_cursor.mc_snum = 1;

+		mx->mx_cursor.mc_top = 0;

+		mx->mx_cursor.mc_flags |= C_INITIALIZED;

+		mx->mx_cursor.mc_pg[0] = fp;

+		mx->mx_cursor.mc_ki[0] = 0;

+		if (mc->mc_db->md_flags & MDB_DUPFIXED) {

+			mx->mx_db.md_flags = MDB_DUPFIXED;

+			mx->mx_db.md_pad = fp->mp_pad;

+			if (mc->mc_db->md_flags & MDB_INTEGERDUP)

+				mx->mx_db.md_flags |= MDB_INTEGERKEY;

+		}

+	}

+	DPRINTF(("Sub-db -%u root page %"Y"u", mx->mx_cursor.mc_dbi,

+		mx->mx_db.md_root));

+	mx->mx_dbflag = DB_VALID|DB_USRVALID|DB_DIRTY; /* DB_DIRTY guides mdb_cursor_touch */

+#if UINT_MAX < SIZE_MAX || defined(MDB_VL32)

+	if (mx->mx_dbx.md_cmp == mdb_cmp_int && mx->mx_db.md_pad == sizeof(mdb_size_t))

+		mx->mx_dbx.md_cmp = mdb_cmp_clong;

+#endif

+}

+

+

+/** Fixup a sorted-dups cursor due to underlying update.

+ *	Sets up some fields that depend on the data from the main cursor.

+ *	Almost the same as init1, but skips initialization steps if the

+ *	xcursor had already been used.

+ * @param[in] mc The main cursor whose sorted-dups cursor is to be fixed up.

+ * @param[in] src_mx The xcursor of an up-to-date cursor.

+ * @param[in] new_dupdata True if converting from a non-#F_DUPDATA item.

+ */

+static void

+mdb_xcursor_init2(MDB_cursor *mc, MDB_xcursor *src_mx, int new_dupdata)

+{

+	MDB_xcursor *mx = mc->mc_xcursor;

+

+	if (new_dupdata) {

+		mx->mx_cursor.mc_snum = 1;

+		mx->mx_cursor.mc_top = 0;

+		mx->mx_cursor.mc_flags |= C_INITIALIZED;

+		mx->mx_cursor.mc_ki[0] = 0;

+		mx->mx_dbflag = DB_VALID|DB_USRVALID|DB_DIRTY; /* DB_DIRTY guides mdb_cursor_touch */

+#if UINT_MAX < SIZE_MAX

+		mx->mx_dbx.md_cmp = src_mx->mx_dbx.md_cmp;

+#endif

+	} else if (!(mx->mx_cursor.mc_flags & C_INITIALIZED)) {

+		return;

+	}

+	mx->mx_db = src_mx->mx_db;

+	mx->mx_cursor.mc_pg[0] = src_mx->mx_cursor.mc_pg[0];

+	DPRINTF(("Sub-db -%u root page %"Y"u", mx->mx_cursor.mc_dbi,

+		mx->mx_db.md_root));

+}

+

+/** Initialize a cursor for a given transaction and database. */

+static void

+mdb_cursor_init(MDB_cursor *mc, MDB_txn *txn, MDB_dbi dbi, MDB_xcursor *mx)

+{

+	mc->mc_next = NULL;

+	mc->mc_backup = NULL;

+	mc->mc_dbi = dbi;

+	mc->mc_txn = txn;

+	mc->mc_db = &txn->mt_dbs[dbi];

+	mc->mc_dbx = &txn->mt_dbxs[dbi];

+	mc->mc_dbflag = &txn->mt_dbflags[dbi];

+	mc->mc_snum = 0;

+	mc->mc_top = 0;

+	mc->mc_pg[0] = 0;

+	mc->mc_ki[0] = 0;

+#ifdef MDB_VL32

+	mc->mc_ovpg = 0;

+#endif

+	mc->mc_flags = txn->mt_flags & (C_ORIG_RDONLY|C_WRITEMAP);

+	if (txn->mt_dbs[dbi].md_flags & MDB_DUPSORT) {

+		mdb_tassert(txn, mx != NULL);

+		mc->mc_xcursor = mx;

+		mdb_xcursor_init0(mc);

+	} else {

+		mc->mc_xcursor = NULL;

+	}

+	if (*mc->mc_dbflag & DB_STALE) {

+		mdb_page_search(mc, NULL, MDB_PS_ROOTONLY);

+	}

+}

+

+int

+mdb_cursor_open(MDB_txn *txn, MDB_dbi dbi, MDB_cursor **ret)

+{

+	MDB_cursor	*mc;

+	size_t size = sizeof(MDB_cursor);

+

+	if (!ret || !TXN_DBI_EXIST(txn, dbi, DB_VALID))

+		return EINVAL;

+

+	if (txn->mt_flags & MDB_TXN_BLOCKED)

+		return MDB_BAD_TXN;

+

+	if (dbi == FREE_DBI && !F_ISSET(txn->mt_flags, MDB_TXN_RDONLY))

+		return EINVAL;

+

+	if (txn->mt_dbs[dbi].md_flags & MDB_DUPSORT)

+		size += sizeof(MDB_xcursor);

+

+	if ((mc = malloc(size)) != NULL) {

+		mdb_cursor_init(mc, txn, dbi, (MDB_xcursor *)(mc + 1));

+		if (txn->mt_cursors) {

+			mc->mc_next = txn->mt_cursors[dbi];

+			txn->mt_cursors[dbi] = mc;

+			mc->mc_flags |= C_UNTRACK;

+		}

+	} else {

+		return ENOMEM;

+	}

+

+	*ret = mc;

+

+	return MDB_SUCCESS;

+}

+

+int

+mdb_cursor_renew(MDB_txn *txn, MDB_cursor *mc)

+{

+	if (!mc || !TXN_DBI_EXIST(txn, mc->mc_dbi, DB_VALID))

+		return EINVAL;

+

+	if ((mc->mc_flags & C_UNTRACK) || txn->mt_cursors)

+		return EINVAL;

+

+	if (txn->mt_flags & MDB_TXN_BLOCKED)

+		return MDB_BAD_TXN;

+

+	mdb_cursor_init(mc, txn, mc->mc_dbi, mc->mc_xcursor);

+	return MDB_SUCCESS;

+}

+

+/* Return the count of duplicate data items for the current key */

+int

+mdb_cursor_count(MDB_cursor *mc, mdb_size_t *countp)

+{

+	MDB_node	*leaf;

+

+	if (mc == NULL || countp == NULL)

+		return EINVAL;

+

+	if (mc->mc_xcursor == NULL)

+		return MDB_INCOMPATIBLE;

+

+	if (mc->mc_txn->mt_flags & MDB_TXN_BLOCKED)

+		return MDB_BAD_TXN;

+

+	if (!(mc->mc_flags & C_INITIALIZED))

+		return EINVAL;

+

+	if (!mc->mc_snum || (mc->mc_flags & C_EOF))

+		return MDB_NOTFOUND;

+

+	leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);

+	if (!F_ISSET(leaf->mn_flags, F_DUPDATA)) {

+		*countp = 1;

+	} else {

+		if (!(mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED))

+			return EINVAL;

+

+		*countp = mc->mc_xcursor->mx_db.md_entries;

+	}

+	return MDB_SUCCESS;

+}

+

+void

+mdb_cursor_close(MDB_cursor *mc)

+{

+	if (mc && !mc->mc_backup) {

+		/* remove from txn, if tracked */

+		if ((mc->mc_flags & C_UNTRACK) && mc->mc_txn->mt_cursors) {

+			MDB_cursor **prev = &mc->mc_txn->mt_cursors[mc->mc_dbi];

+			while (*prev && *prev != mc) prev = &(*prev)->mc_next;

+			if (*prev == mc)

+				*prev = mc->mc_next;

+		}

+		free(mc);

+	}

+}

+

+MDB_txn *

+mdb_cursor_txn(MDB_cursor *mc)

+{

+	if (!mc) return NULL;

+	return mc->mc_txn;

+}

+

+MDB_dbi

+mdb_cursor_dbi(MDB_cursor *mc)

+{

+	return mc->mc_dbi;

+}

+

+/** Replace the key for a branch node with a new key.

+ * @param[in] mc Cursor pointing to the node to operate on.

+ * @param[in] key The new key to use.

+ * @return 0 on success, non-zero on failure.

+ */

+static int

+mdb_update_key(MDB_cursor *mc, MDB_val *key)

+{

+	MDB_page		*mp;

+	MDB_node		*node;

+	char			*base;

+	size_t			 len;

+	int				 delta, ksize, oksize;

+	indx_t			 ptr, i, numkeys, indx;

+	DKBUF;

+

+	indx = mc->mc_ki[mc->mc_top];

+	mp = mc->mc_pg[mc->mc_top];

+	node = NODEPTR(mp, indx);

+	ptr = mp->mp_ptrs[indx];

+#if MDB_DEBUG

+	{

+		MDB_val	k2;

+		char kbuf2[DKBUF_MAXKEYSIZE*2+1];

+		k2.mv_data = NODEKEY(node);

+		k2.mv_size = node->mn_ksize;

+		DPRINTF(("update key %u (ofs %u) [%s] to [%s] on page %"Y"u",

+			indx, ptr,

+			mdb_dkey(&k2, kbuf2),

+			DKEY(key),

+			mp->mp_pgno));

+	}

+#endif

+

+	/* Sizes must be 2-byte aligned. */

+	ksize = EVEN(key->mv_size);

+	oksize = EVEN(node->mn_ksize);

+	delta = ksize - oksize;

+

+	/* Shift node contents if EVEN(key length) changed. */

+	if (delta) {

+		if (delta > 0 && SIZELEFT(mp) < delta) {

+			pgno_t pgno;

+			/* not enough space left, do a delete and split */

+			DPRINTF(("Not enough room, delta = %d, splitting...", delta));

+			pgno = NODEPGNO(node);

+			mdb_node_del(mc, 0);

+			return mdb_page_split(mc, key, NULL, pgno, MDB_SPLIT_REPLACE);

+		}

+

+		numkeys = NUMKEYS(mp);

+		for (i = 0; i < numkeys; i++) {

+			if (mp->mp_ptrs[i] <= ptr)

+				mp->mp_ptrs[i] -= delta;

+		}

+

+		base = (char *)mp + mp->mp_upper + PAGEBASE;

+		len = ptr - mp->mp_upper + NODESIZE;

+		memmove(base - delta, base, len);

+		mp->mp_upper -= delta;

+

+		node = NODEPTR(mp, indx);

+	}

+

+	/* But even if no shift was needed, update ksize */

+	if (node->mn_ksize != key->mv_size)

+		node->mn_ksize = key->mv_size;

+

+	if (key->mv_size)

+		memcpy(NODEKEY(node), key->mv_data, key->mv_size);

+

+	return MDB_SUCCESS;

+}

+

+static void

+mdb_cursor_copy(const MDB_cursor *csrc, MDB_cursor *cdst);

+

+/** Perform \b act while tracking temporary cursor \b mn */

+#define WITH_CURSOR_TRACKING(mn, act) do { \

+	MDB_cursor dummy, *tracked, **tp = &(mn).mc_txn->mt_cursors[mn.mc_dbi]; \

+	if ((mn).mc_flags & C_SUB) { \

+		dummy.mc_flags =  C_INITIALIZED; \

+		dummy.mc_xcursor = (MDB_xcursor *)&(mn);	\

+		tracked = &dummy; \

+	} else { \

+		tracked = &(mn); \

+	} \

+	tracked->mc_next = *tp; \

+	*tp = tracked; \

+	{ act; } \

+	*tp = tracked->mc_next; \

+} while (0)

+

+/** Move a node from csrc to cdst.

+ */

+static int

+mdb_node_move(MDB_cursor *csrc, MDB_cursor *cdst, int fromleft)

+{

+	MDB_node		*srcnode;

+	MDB_val		 key, data;

+	pgno_t	srcpg;

+	MDB_cursor mn;

+	int			 rc;

+	unsigned short flags;

+

+	DKBUF;

+

+	/* Mark src and dst as dirty. */

+	if ((rc = mdb_page_touch(csrc)) ||

+	    (rc = mdb_page_touch(cdst)))

+		return rc;

+

+	if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {

+		key.mv_size = csrc->mc_db->md_pad;

+		key.mv_data = LEAF2KEY(csrc->mc_pg[csrc->mc_top], csrc->mc_ki[csrc->mc_top], key.mv_size);

+		data.mv_size = 0;

+		data.mv_data = NULL;

+		srcpg = 0;

+		flags = 0;

+	} else {

+		srcnode = NODEPTR(csrc->mc_pg[csrc->mc_top], csrc->mc_ki[csrc->mc_top]);

+		mdb_cassert(csrc, !((size_t)srcnode & 1));

+		srcpg = NODEPGNO(srcnode);

+		flags = srcnode->mn_flags;

+		if (csrc->mc_ki[csrc->mc_top] == 0 && IS_BRANCH(csrc->mc_pg[csrc->mc_top])) {

+			unsigned int snum = csrc->mc_snum;

+			MDB_node *s2;

+			/* must find the lowest key below src */

+			rc = mdb_page_search_lowest(csrc);

+			if (rc)

+				return rc;

+			if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {

+				key.mv_size = csrc->mc_db->md_pad;

+				key.mv_data = LEAF2KEY(csrc->mc_pg[csrc->mc_top], 0, key.mv_size);

+			} else {

+				s2 = NODEPTR(csrc->mc_pg[csrc->mc_top], 0);

+				key.mv_size = NODEKSZ(s2);

+				key.mv_data = NODEKEY(s2);

+			}

+			csrc->mc_snum = snum--;

+			csrc->mc_top = snum;

+		} else {

+			key.mv_size = NODEKSZ(srcnode);

+			key.mv_data = NODEKEY(srcnode);

+		}

+		data.mv_size = NODEDSZ(srcnode);

+		data.mv_data = NODEDATA(srcnode);

+	}

+	mn.mc_xcursor = NULL;

+	if (IS_BRANCH(cdst->mc_pg[cdst->mc_top]) && cdst->mc_ki[cdst->mc_top] == 0) {

+		unsigned int snum = cdst->mc_snum;

+		MDB_node *s2;

+		MDB_val bkey;

+		/* must find the lowest key below dst */

+		mdb_cursor_copy(cdst, &mn);

+		rc = mdb_page_search_lowest(&mn);

+		if (rc)

+			return rc;

+		if (IS_LEAF2(mn.mc_pg[mn.mc_top])) {

+			bkey.mv_size = mn.mc_db->md_pad;

+			bkey.mv_data = LEAF2KEY(mn.mc_pg[mn.mc_top], 0, bkey.mv_size);

+		} else {

+			s2 = NODEPTR(mn.mc_pg[mn.mc_top], 0);

+			bkey.mv_size = NODEKSZ(s2);

+			bkey.mv_data = NODEKEY(s2);

+		}

+		mn.mc_snum = snum--;

+		mn.mc_top = snum;

+		mn.mc_ki[snum] = 0;

+		rc = mdb_update_key(&mn, &bkey);

+		if (rc)

+			return rc;

+	}

+

+	DPRINTF(("moving %s node %u [%s] on page %"Y"u to node %u on page %"Y"u",

+	    IS_LEAF(csrc->mc_pg[csrc->mc_top]) ? "leaf" : "branch",

+	    csrc->mc_ki[csrc->mc_top],

+		DKEY(&key),

+	    csrc->mc_pg[csrc->mc_top]->mp_pgno,

+	    cdst->mc_ki[cdst->mc_top], cdst->mc_pg[cdst->mc_top]->mp_pgno));

+

+	/* Add the node to the destination page.

+	 */

+	rc = mdb_node_add(cdst, cdst->mc_ki[cdst->mc_top], &key, &data, srcpg, flags);

+	if (rc != MDB_SUCCESS)

+		return rc;

+

+	/* Delete the node from the source page.

+	 */

+	mdb_node_del(csrc, key.mv_size);

+

+	{

+		/* Adjust other cursors pointing to mp */

+		MDB_cursor *m2, *m3;

+		MDB_dbi dbi = csrc->mc_dbi;

+		MDB_page *mpd, *mps;

+

+		mps = csrc->mc_pg[csrc->mc_top];

+		/* If we're adding on the left, bump others up */

+		if (fromleft) {

+			mpd = cdst->mc_pg[csrc->mc_top];

+			for (m2 = csrc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {

+				if (csrc->mc_flags & C_SUB)

+					m3 = &m2->mc_xcursor->mx_cursor;

+				else

+					m3 = m2;

+				if (!(m3->mc_flags & C_INITIALIZED) || m3->mc_top < csrc->mc_top)

+					continue;

+				if (m3 != cdst &&

+					m3->mc_pg[csrc->mc_top] == mpd &&

+					m3->mc_ki[csrc->mc_top] >= cdst->mc_ki[csrc->mc_top]) {

+					m3->mc_ki[csrc->mc_top]++;

+				}

+				if (m3 !=csrc &&

+					m3->mc_pg[csrc->mc_top] == mps &&

+					m3->mc_ki[csrc->mc_top] == csrc->mc_ki[csrc->mc_top]) {

+					m3->mc_pg[csrc->mc_top] = cdst->mc_pg[cdst->mc_top];

+					m3->mc_ki[csrc->mc_top] = cdst->mc_ki[cdst->mc_top];

+					m3->mc_ki[csrc->mc_top-1]++;

+				}

+				if (m3->mc_xcursor && (m3->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED) &&

+					IS_LEAF(mps)) {

+					MDB_node *node = NODEPTR(m3->mc_pg[csrc->mc_top], m3->mc_ki[csrc->mc_top]);

+					if ((node->mn_flags & (F_DUPDATA|F_SUBDATA)) == F_DUPDATA)

+						m3->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(node);

+				}

+			}

+		} else

+		/* Adding on the right, bump others down */

+		{

+			for (m2 = csrc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {

+				if (csrc->mc_flags & C_SUB)

+					m3 = &m2->mc_xcursor->mx_cursor;

+				else

+					m3 = m2;

+				if (m3 == csrc) continue;

+				if (!(m3->mc_flags & C_INITIALIZED) || m3->mc_top < csrc->mc_top)

+					continue;

+				if (m3->mc_pg[csrc->mc_top] == mps) {

+					if (!m3->mc_ki[csrc->mc_top]) {

+						m3->mc_pg[csrc->mc_top] = cdst->mc_pg[cdst->mc_top];

+						m3->mc_ki[csrc->mc_top] = cdst->mc_ki[cdst->mc_top];

+						m3->mc_ki[csrc->mc_top-1]--;

+					} else {

+						m3->mc_ki[csrc->mc_top]--;

+					}

+					if (m3->mc_xcursor && (m3->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED) &&

+						IS_LEAF(mps)) {

+						MDB_node *node = NODEPTR(m3->mc_pg[csrc->mc_top], m3->mc_ki[csrc->mc_top]);

+						if ((node->mn_flags & (F_DUPDATA|F_SUBDATA)) == F_DUPDATA)

+							m3->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(node);

+					}

+				}

+			}

+		}

+	}

+

+	/* Update the parent separators.

+	 */

+	if (csrc->mc_ki[csrc->mc_top] == 0) {

+		if (csrc->mc_ki[csrc->mc_top-1] != 0) {

+			if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {

+				key.mv_data = LEAF2KEY(csrc->mc_pg[csrc->mc_top], 0, key.mv_size);

+			} else {

+				srcnode = NODEPTR(csrc->mc_pg[csrc->mc_top], 0);

+				key.mv_size = NODEKSZ(srcnode);

+				key.mv_data = NODEKEY(srcnode);

+			}

+			DPRINTF(("update separator for source page %"Y"u to [%s]",

+				csrc->mc_pg[csrc->mc_top]->mp_pgno, DKEY(&key)));

+			mdb_cursor_copy(csrc, &mn);

+			mn.mc_snum--;

+			mn.mc_top--;

+			/* We want mdb_rebalance to find mn when doing fixups */

+			WITH_CURSOR_TRACKING(mn,

+				rc = mdb_update_key(&mn, &key));

+			if (rc)

+				return rc;

+		}

+		if (IS_BRANCH(csrc->mc_pg[csrc->mc_top])) {

+			MDB_val	 nullkey;

+			indx_t	ix = csrc->mc_ki[csrc->mc_top];

+			nullkey.mv_size = 0;

+			csrc->mc_ki[csrc->mc_top] = 0;

+			rc = mdb_update_key(csrc, &nullkey);

+			csrc->mc_ki[csrc->mc_top] = ix;

+			mdb_cassert(csrc, rc == MDB_SUCCESS);

+		}

+	}

+

+	if (cdst->mc_ki[cdst->mc_top] == 0) {

+		if (cdst->mc_ki[cdst->mc_top-1] != 0) {

+			if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {

+				key.mv_data = LEAF2KEY(cdst->mc_pg[cdst->mc_top], 0, key.mv_size);

+			} else {

+				srcnode = NODEPTR(cdst->mc_pg[cdst->mc_top], 0);

+				key.mv_size = NODEKSZ(srcnode);

+				key.mv_data = NODEKEY(srcnode);

+			}

+			DPRINTF(("update separator for destination page %"Y"u to [%s]",

+				cdst->mc_pg[cdst->mc_top]->mp_pgno, DKEY(&key)));

+			mdb_cursor_copy(cdst, &mn);

+			mn.mc_snum--;

+			mn.mc_top--;

+			/* We want mdb_rebalance to find mn when doing fixups */

+			WITH_CURSOR_TRACKING(mn,

+				rc = mdb_update_key(&mn, &key));

+			if (rc)

+				return rc;

+		}

+		if (IS_BRANCH(cdst->mc_pg[cdst->mc_top])) {

+			MDB_val	 nullkey;

+			indx_t	ix = cdst->mc_ki[cdst->mc_top];

+			nullkey.mv_size = 0;

+			cdst->mc_ki[cdst->mc_top] = 0;

+			rc = mdb_update_key(cdst, &nullkey);

+			cdst->mc_ki[cdst->mc_top] = ix;

+			mdb_cassert(cdst, rc == MDB_SUCCESS);

+		}

+	}

+

+	return MDB_SUCCESS;

+}

+

+/** Merge one page into another.

+ *  The nodes from the page pointed to by \b csrc will

+ *	be copied to the page pointed to by \b cdst and then

+ *	the \b csrc page will be freed.

+ * @param[in] csrc Cursor pointing to the source page.

+ * @param[in] cdst Cursor pointing to the destination page.

+ * @return 0 on success, non-zero on failure.

+ */

+static int

+mdb_page_merge(MDB_cursor *csrc, MDB_cursor *cdst)

+{

+	MDB_page	*psrc, *pdst;

+	MDB_node	*srcnode;

+	MDB_val		 key, data;

+	unsigned	 nkeys;

+	int			 rc;

+	indx_t		 i, j;

+

+	psrc = csrc->mc_pg[csrc->mc_top];

+	pdst = cdst->mc_pg[cdst->mc_top];

+

+	DPRINTF(("merging page %"Y"u into %"Y"u", psrc->mp_pgno, pdst->mp_pgno));

+

+	mdb_cassert(csrc, csrc->mc_snum > 1);	/* can't merge root page */

+	mdb_cassert(csrc, cdst->mc_snum > 1);

+

+	/* Mark dst as dirty. */

+	if ((rc = mdb_page_touch(cdst)))

+		return rc;

+

+	/* get dst page again now that we've touched it. */

+	pdst = cdst->mc_pg[cdst->mc_top];

+

+	/* Move all nodes from src to dst.

+	 */

+	j = nkeys = NUMKEYS(pdst);

+	if (IS_LEAF2(psrc)) {

+		key.mv_size = csrc->mc_db->md_pad;

+		key.mv_data = METADATA(psrc);

+		for (i = 0; i < NUMKEYS(psrc); i++, j++) {

+			rc = mdb_node_add(cdst, j, &key, NULL, 0, 0);

+			if (rc != MDB_SUCCESS)

+				return rc;

+			key.mv_data = (char *)key.mv_data + key.mv_size;

+		}

+	} else {

+		for (i = 0; i < NUMKEYS(psrc); i++, j++) {

+			srcnode = NODEPTR(psrc, i);

+			if (i == 0 && IS_BRANCH(psrc)) {

+				MDB_cursor mn;

+				MDB_node *s2;

+				mdb_cursor_copy(csrc, &mn);

+				mn.mc_xcursor = NULL;

+				/* must find the lowest key below src */

+				rc = mdb_page_search_lowest(&mn);

+				if (rc)

+					return rc;

+				if (IS_LEAF2(mn.mc_pg[mn.mc_top])) {

+					key.mv_size = mn.mc_db->md_pad;

+					key.mv_data = LEAF2KEY(mn.mc_pg[mn.mc_top], 0, key.mv_size);

+				} else {

+					s2 = NODEPTR(mn.mc_pg[mn.mc_top], 0);

+					key.mv_size = NODEKSZ(s2);

+					key.mv_data = NODEKEY(s2);

+				}

+			} else {

+				key.mv_size = srcnode->mn_ksize;

+				key.mv_data = NODEKEY(srcnode);

+			}

+

+			data.mv_size = NODEDSZ(srcnode);

+			data.mv_data = NODEDATA(srcnode);

+			rc = mdb_node_add(cdst, j, &key, &data, NODEPGNO(srcnode), srcnode->mn_flags);

+			if (rc != MDB_SUCCESS)

+				return rc;

+		}

+	}

+

+	DPRINTF(("dst page %"Y"u now has %u keys (%.1f%% filled)",

+	    pdst->mp_pgno, NUMKEYS(pdst),

+		(float)PAGEFILL(cdst->mc_txn->mt_env, pdst) / 10));

+

+	/* Unlink the src page from parent and add to free list.

+	 */

+	csrc->mc_top--;

+	mdb_node_del(csrc, 0);

+	if (csrc->mc_ki[csrc->mc_top] == 0) {

+		key.mv_size = 0;

+		rc = mdb_update_key(csrc, &key);

+		if (rc) {

+			csrc->mc_top++;

+			return rc;

+		}

+	}

+	csrc->mc_top++;

+

+	psrc = csrc->mc_pg[csrc->mc_top];

+	/* If not operating on FreeDB, allow this page to be reused

+	 * in this txn. Otherwise just add to free list.

+	 */

+	rc = mdb_page_loose(csrc, psrc);

+	if (rc)

+		return rc;

+	if (IS_LEAF(psrc))

+		csrc->mc_db->md_leaf_pages--;

+	else

+		csrc->mc_db->md_branch_pages--;

+	{

+		/* Adjust other cursors pointing to mp */

+		MDB_cursor *m2, *m3;

+		MDB_dbi dbi = csrc->mc_dbi;

+		unsigned int top = csrc->mc_top;

+

+		for (m2 = csrc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {

+			if (csrc->mc_flags & C_SUB)

+				m3 = &m2->mc_xcursor->mx_cursor;

+			else

+				m3 = m2;

+			if (m3 == csrc) continue;

+			if (m3->mc_snum < csrc->mc_snum) continue;

+			if (m3->mc_pg[top] == psrc) {

+				m3->mc_pg[top] = pdst;

+				m3->mc_ki[top] += nkeys;

+				m3->mc_ki[top-1] = cdst->mc_ki[top-1];

+			} else if (m3->mc_pg[top-1] == csrc->mc_pg[top-1] &&

+				m3->mc_ki[top-1] > csrc->mc_ki[top-1]) {

+				m3->mc_ki[top-1]--;

+			}

+			if (m3->mc_xcursor && (m3->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED) &&

+				IS_LEAF(psrc)) {

+				MDB_node *node = NODEPTR(m3->mc_pg[top], m3->mc_ki[top]);

+				if ((node->mn_flags & (F_DUPDATA|F_SUBDATA)) == F_DUPDATA)

+					m3->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(node);

+			}

+		}

+	}

+	{

+		unsigned int snum = cdst->mc_snum;

+		uint16_t depth = cdst->mc_db->md_depth;

+		mdb_cursor_pop(cdst);

+		rc = mdb_rebalance(cdst);

+		/* Did the tree height change? */

+		if (depth != cdst->mc_db->md_depth)

+			snum += cdst->mc_db->md_depth - depth;

+		cdst->mc_snum = snum;

+		cdst->mc_top = snum-1;

+	}

+	return rc;

+}

+

+/** Copy the contents of a cursor.

+ * @param[in] csrc The cursor to copy from.

+ * @param[out] cdst The cursor to copy to.

+ */

+static void

+mdb_cursor_copy(const MDB_cursor *csrc, MDB_cursor *cdst)

+{

+	unsigned int i;

+

+	cdst->mc_txn = csrc->mc_txn;

+	cdst->mc_dbi = csrc->mc_dbi;

+	cdst->mc_db  = csrc->mc_db;

+	cdst->mc_dbx = csrc->mc_dbx;

+	cdst->mc_snum = csrc->mc_snum;

+	cdst->mc_top = csrc->mc_top;

+	cdst->mc_flags = csrc->mc_flags;

+#ifdef MDB_VL32

+	cdst->mc_ovpg = csrc->mc_ovpg;

+#endif

+

+	for (i=0; i<csrc->mc_snum; i++) {

+		cdst->mc_pg[i] = csrc->mc_pg[i];

+		cdst->mc_ki[i] = csrc->mc_ki[i];

+	}

+}

+

+/** Rebalance the tree after a delete operation.

+ * @param[in] mc Cursor pointing to the page where rebalancing

+ * should begin.

+ * @return 0 on success, non-zero on failure.

+ */

+static int

+mdb_rebalance(MDB_cursor *mc)

+{

+	MDB_node	*node;

+	int rc, fromleft;

+	unsigned int ptop, minkeys, thresh;

+	MDB_cursor	mn;

+	indx_t oldki;

+

+	if (IS_BRANCH(mc->mc_pg[mc->mc_top])) {

+		minkeys = 2;

+		thresh = 1;

+	} else {

+		minkeys = 1;

+		thresh = FILL_THRESHOLD;

+	}

+	DPRINTF(("rebalancing %s page %"Y"u (has %u keys, %.1f%% full)",

+	    IS_LEAF(mc->mc_pg[mc->mc_top]) ? "leaf" : "branch",

+	    mdb_dbg_pgno(mc->mc_pg[mc->mc_top]), NUMKEYS(mc->mc_pg[mc->mc_top]),

+		(float)PAGEFILL(mc->mc_txn->mt_env, mc->mc_pg[mc->mc_top]) / 10));

+

+	if (PAGEFILL(mc->mc_txn->mt_env, mc->mc_pg[mc->mc_top]) >= thresh &&

+		NUMKEYS(mc->mc_pg[mc->mc_top]) >= minkeys) {

+		DPRINTF(("no need to rebalance page %"Y"u, above fill threshold",

+		    mdb_dbg_pgno(mc->mc_pg[mc->mc_top])));

+		return MDB_SUCCESS;

+	}

+

+	if (mc->mc_snum < 2) {

+		MDB_page *mp = mc->mc_pg[0];

+		if (IS_SUBP(mp)) {

+			DPUTS("Can't rebalance a subpage, ignoring");

+			return MDB_SUCCESS;

+		}

+		if (NUMKEYS(mp) == 0) {

+			DPUTS("tree is completely empty");

+			mc->mc_db->md_root = P_INVALID;

+			mc->mc_db->md_depth = 0;

+			mc->mc_db->md_leaf_pages = 0;

+			rc = mdb_midl_append(&mc->mc_txn->mt_free_pgs, mp->mp_pgno);

+			if (rc)

+				return rc;

+			/* Adjust cursors pointing to mp */

+			mc->mc_snum = 0;

+			mc->mc_top = 0;

+			mc->mc_flags &= ~C_INITIALIZED;

+			{

+				MDB_cursor *m2, *m3;

+				MDB_dbi dbi = mc->mc_dbi;

+

+				for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {

+					if (mc->mc_flags & C_SUB)

+						m3 = &m2->mc_xcursor->mx_cursor;

+					else

+						m3 = m2;

+					if (!(m3->mc_flags & C_INITIALIZED) || (m3->mc_snum < mc->mc_snum))

+						continue;

+					if (m3->mc_pg[0] == mp) {

+						m3->mc_snum = 0;

+						m3->mc_top = 0;

+						m3->mc_flags &= ~C_INITIALIZED;

+					}

+				}

+			}

+		} else if (IS_BRANCH(mp) && NUMKEYS(mp) == 1) {

+			int i;

+			DPUTS("collapsing root page!");

+			rc = mdb_midl_append(&mc->mc_txn->mt_free_pgs, mp->mp_pgno);

+			if (rc)

+				return rc;

+			mc->mc_db->md_root = NODEPGNO(NODEPTR(mp, 0));

+			rc = mdb_page_get(mc, mc->mc_db->md_root, &mc->mc_pg[0], NULL);

+			if (rc)

+				return rc;

+			mc->mc_db->md_depth--;

+			mc->mc_db->md_branch_pages--;

+			mc->mc_ki[0] = mc->mc_ki[1];

+			for (i = 1; i<mc->mc_db->md_depth; i++) {

+				mc->mc_pg[i] = mc->mc_pg[i+1];

+				mc->mc_ki[i] = mc->mc_ki[i+1];

+			}

+			{

+				/* Adjust other cursors pointing to mp */

+				MDB_cursor *m2, *m3;

+				MDB_dbi dbi = mc->mc_dbi;

+

+				for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {

+					if (mc->mc_flags & C_SUB)

+						m3 = &m2->mc_xcursor->mx_cursor;

+					else

+						m3 = m2;

+					if (m3 == mc) continue;

+					if (!(m3->mc_flags & C_INITIALIZED))

+						continue;

+					if (m3->mc_pg[0] == mp) {

+						for (i=0; i<mc->mc_db->md_depth; i++) {

+							m3->mc_pg[i] = m3->mc_pg[i+1];

+							m3->mc_ki[i] = m3->mc_ki[i+1];

+						}

+						m3->mc_snum--;

+						m3->mc_top--;

+					}

+				}

+			}

+		} else

+			DPUTS("root page doesn't need rebalancing");

+		return MDB_SUCCESS;

+	}

+

+	/* The parent (branch page) must have at least 2 pointers,

+	 * otherwise the tree is invalid.

+	 */

+	ptop = mc->mc_top-1;

+	mdb_cassert(mc, NUMKEYS(mc->mc_pg[ptop]) > 1);

+

+	/* Leaf page fill factor is below the threshold.

+	 * Try to move keys from left or right neighbor, or

+	 * merge with a neighbor page.

+	 */

+

+	/* Find neighbors.

+	 */

+	mdb_cursor_copy(mc, &mn);

+	mn.mc_xcursor = NULL;

+

+	oldki = mc->mc_ki[mc->mc_top];

+	if (mc->mc_ki[ptop] == 0) {

+		/* We're the leftmost leaf in our parent.

+		 */

+		DPUTS("reading right neighbor");

+		mn.mc_ki[ptop]++;

+		node = NODEPTR(mc->mc_pg[ptop], mn.mc_ki[ptop]);

+		rc = mdb_page_get(mc, NODEPGNO(node), &mn.mc_pg[mn.mc_top], NULL);

+		if (rc)

+			return rc;

+		mn.mc_ki[mn.mc_top] = 0;

+		mc->mc_ki[mc->mc_top] = NUMKEYS(mc->mc_pg[mc->mc_top]);

+		fromleft = 0;

+	} else {

+		/* There is at least one neighbor to the left.

+		 */

+		DPUTS("reading left neighbor");

+		mn.mc_ki[ptop]--;

+		node = NODEPTR(mc->mc_pg[ptop], mn.mc_ki[ptop]);

+		rc = mdb_page_get(mc, NODEPGNO(node), &mn.mc_pg[mn.mc_top], NULL);

+		if (rc)

+			return rc;

+		mn.mc_ki[mn.mc_top] = NUMKEYS(mn.mc_pg[mn.mc_top]) - 1;

+		mc->mc_ki[mc->mc_top] = 0;

+		fromleft = 1;

+	}

+

+	DPRINTF(("found neighbor page %"Y"u (%u keys, %.1f%% full)",

+	    mn.mc_pg[mn.mc_top]->mp_pgno, NUMKEYS(mn.mc_pg[mn.mc_top]),

+		(float)PAGEFILL(mc->mc_txn->mt_env, mn.mc_pg[mn.mc_top]) / 10));

+

+	/* If the neighbor page is above threshold and has enough keys,

+	 * move one key from it. Otherwise we should try to merge them.

+	 * (A branch page must never have less than 2 keys.)

+	 */

+	if (PAGEFILL(mc->mc_txn->mt_env, mn.mc_pg[mn.mc_top]) >= thresh && NUMKEYS(mn.mc_pg[mn.mc_top]) > minkeys) {

+		rc = mdb_node_move(&mn, mc, fromleft);

+		if (fromleft) {

+			/* if we inserted on left, bump position up */

+			oldki++;

+		}

+	} else {

+		if (!fromleft) {

+			rc = mdb_page_merge(&mn, mc);

+		} else {

+			oldki += NUMKEYS(mn.mc_pg[mn.mc_top]);

+			mn.mc_ki[mn.mc_top] += mc->mc_ki[mn.mc_top] + 1;

+			/* We want mdb_rebalance to find mn when doing fixups */

+			WITH_CURSOR_TRACKING(mn,

+				rc = mdb_page_merge(mc, &mn));

+			mdb_cursor_copy(&mn, mc);

+		}

+		mc->mc_flags &= ~C_EOF;

+	}

+	mc->mc_ki[mc->mc_top] = oldki;

+	return rc;

+}

+

+/** Complete a delete operation started by #mdb_cursor_del(). */

+static int

+mdb_cursor_del0(MDB_cursor *mc)

+{

+	int rc;

+	MDB_page *mp;

+	indx_t ki;

+	unsigned int nkeys;

+	MDB_cursor *m2, *m3;

+	MDB_dbi dbi = mc->mc_dbi;

+

+	ki = mc->mc_ki[mc->mc_top];

+	mp = mc->mc_pg[mc->mc_top];

+	mdb_node_del(mc, mc->mc_db->md_pad);

+	mc->mc_db->md_entries--;

+	{

+		/* Adjust other cursors pointing to mp */

+		for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {

+			m3 = (mc->mc_flags & C_SUB) ? &m2->mc_xcursor->mx_cursor : m2;

+			if (! (m2->mc_flags & m3->mc_flags & C_INITIALIZED))

+				continue;

+			if (m3 == mc || m3->mc_snum < mc->mc_snum)

+				continue;

+			if (m3->mc_pg[mc->mc_top] == mp) {

+				if (m3->mc_ki[mc->mc_top] == ki) {

+					m3->mc_flags |= C_DEL;

+				} else if (m3->mc_ki[mc->mc_top] > ki) {

+					m3->mc_ki[mc->mc_top]--;

+				}

+				if (m3->mc_xcursor && (m3->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED)) {

+					MDB_node *node = NODEPTR(m3->mc_pg[mc->mc_top], m3->mc_ki[mc->mc_top]);

+					if ((node->mn_flags & (F_DUPDATA|F_SUBDATA)) == F_DUPDATA)

+						m3->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(node);

+				}

+			}

+		}

+	}

+	rc = mdb_rebalance(mc);

+

+	if (rc == MDB_SUCCESS) {

+		/* DB is totally empty now, just bail out.

+		 * Other cursors adjustments were already done

+		 * by mdb_rebalance and aren't needed here.

+		 */

+		if (!mc->mc_snum)

+			return rc;

+

+		mp = mc->mc_pg[mc->mc_top];

+		nkeys = NUMKEYS(mp);

+

+		/* Adjust other cursors pointing to mp */

+		for (m2 = mc->mc_txn->mt_cursors[dbi]; !rc && m2; m2=m2->mc_next) {

+			m3 = (mc->mc_flags & C_SUB) ? &m2->mc_xcursor->mx_cursor : m2;

+			if (! (m2->mc_flags & m3->mc_flags & C_INITIALIZED))

+				continue;

+			if (m3->mc_snum < mc->mc_snum)

+				continue;

+			if (m3->mc_pg[mc->mc_top] == mp) {

+				/* if m3 points past last node in page, find next sibling */

+				if (m3->mc_ki[mc->mc_top] >= mc->mc_ki[mc->mc_top]) {

+					if (m3->mc_ki[mc->mc_top] >= nkeys) {

+						rc = mdb_cursor_sibling(m3, 1);

+						if (rc == MDB_NOTFOUND) {

+							m3->mc_flags |= C_EOF;

+							rc = MDB_SUCCESS;

+							continue;

+						}

+					}

+					if (mc->mc_db->md_flags & MDB_DUPSORT) {

+						MDB_node *node = NODEPTR(m3->mc_pg[m3->mc_top], m3->mc_ki[m3->mc_top]);

+						if (node->mn_flags & F_DUPDATA) {

+							mdb_xcursor_init1(m3, node);

+							m3->mc_xcursor->mx_cursor.mc_flags |= C_DEL;

+						}

+					}

+				}

+			}

+		}

+		mc->mc_flags |= C_DEL;

+	}

+

+	if (rc)

+		mc->mc_txn->mt_flags |= MDB_TXN_ERROR;

+	return rc;

+}

+

+int

+mdb_del(MDB_txn *txn, MDB_dbi dbi,

+    MDB_val *key, MDB_val *data)

+{

+	if (!key || !TXN_DBI_EXIST(txn, dbi, DB_USRVALID))

+		return EINVAL;

+

+	if (txn->mt_flags & (MDB_TXN_RDONLY|MDB_TXN_BLOCKED))

+		return (txn->mt_flags & MDB_TXN_RDONLY) ? EACCES : MDB_BAD_TXN;

+

+	if (!F_ISSET(txn->mt_dbs[dbi].md_flags, MDB_DUPSORT)) {

+		/* must ignore any data */

+		data = NULL;

+	}

+

+	return mdb_del0(txn, dbi, key, data, 0);

+}

+

+static int

+mdb_del0(MDB_txn *txn, MDB_dbi dbi,

+	MDB_val *key, MDB_val *data, unsigned flags)

+{

+	MDB_cursor mc;

+	MDB_xcursor mx;

+	MDB_cursor_op op;

+	MDB_val rdata, *xdata;

+	int		 rc, exact = 0;

+	DKBUF;

+

+	DPRINTF(("====> delete db %u key [%s]", dbi, DKEY(key)));

+

+	mdb_cursor_init(&mc, txn, dbi, &mx);

+

+	if (data) {

+		op = MDB_GET_BOTH;

+		rdata = *data;

+		xdata = &rdata;

+	} else {

+		op = MDB_SET;

+		xdata = NULL;

+		flags |= MDB_NODUPDATA;

+	}

+	rc = mdb_cursor_set(&mc, key, xdata, op, &exact);

+	if (rc == 0) {

+		/* let mdb_page_split know about this cursor if needed:

+		 * delete will trigger a rebalance; if it needs to move

+		 * a node from one page to another, it will have to

+		 * update the parent's separator key(s). If the new sepkey

+		 * is larger than the current one, the parent page may

+		 * run out of space, triggering a split. We need this

+		 * cursor to be consistent until the end of the rebalance.

+		 */

+		mc.mc_flags |= C_UNTRACK;

+		mc.mc_next = txn->mt_cursors[dbi];

+		txn->mt_cursors[dbi] = &mc;

+		rc = mdb_cursor_del(&mc, flags);

+		txn->mt_cursors[dbi] = mc.mc_next;

+	}

+	return rc;

+}

+

+/** Split a page and insert a new node.

+ * @param[in,out] mc Cursor pointing to the page and desired insertion index.

+ * The cursor will be updated to point to the actual page and index where

+ * the node got inserted after the split.

+ * @param[in] newkey The key for the newly inserted node.

+ * @param[in] newdata The data for the newly inserted node.

+ * @param[in] newpgno The page number, if the new node is a branch node.

+ * @param[in] nflags The #NODE_ADD_FLAGS for the new node.

+ * @return 0 on success, non-zero on failure.

+ */

+static int

+mdb_page_split(MDB_cursor *mc, MDB_val *newkey, MDB_val *newdata, pgno_t newpgno,

+	unsigned int nflags)

+{

+	unsigned int flags;

+	int		 rc = MDB_SUCCESS, new_root = 0, did_split = 0;

+	indx_t		 newindx;

+	pgno_t		 pgno = 0;

+	int	 i, j, split_indx, nkeys, pmax;

+	MDB_env 	*env = mc->mc_txn->mt_env;

+	MDB_node	*node;

+	MDB_val	 sepkey, rkey, xdata, *rdata = &xdata;

+	MDB_page	*copy = NULL;

+	MDB_page	*mp, *rp, *pp;

+	int ptop;

+	MDB_cursor	mn;

+	DKBUF;

+

+	mp = mc->mc_pg[mc->mc_top];

+	newindx = mc->mc_ki[mc->mc_top];

+	nkeys = NUMKEYS(mp);

+

+	DPRINTF(("-----> splitting %s page %"Y"u and adding [%s] at index %i/%i",

+	    IS_LEAF(mp) ? "leaf" : "branch", mp->mp_pgno,

+	    DKEY(newkey), mc->mc_ki[mc->mc_top], nkeys));

+

+	/* Create a right sibling. */

+	if ((rc = mdb_page_new(mc, mp->mp_flags, 1, &rp)))

+		return rc;

+	rp->mp_pad = mp->mp_pad;

+	DPRINTF(("new right sibling: page %"Y"u", rp->mp_pgno));

+

+	/* Usually when splitting the root page, the cursor

+	 * height is 1. But when called from mdb_update_key,

+	 * the cursor height may be greater because it walks

+	 * up the stack while finding the branch slot to update.

+	 */

+	if (mc->mc_top < 1) {

+		if ((rc = mdb_page_new(mc, P_BRANCH, 1, &pp)))

+			goto done;

+		/* shift current top to make room for new parent */

+		for (i=mc->mc_snum; i>0; i--) {

+			mc->mc_pg[i] = mc->mc_pg[i-1];

+			mc->mc_ki[i] = mc->mc_ki[i-1];

+		}

+		mc->mc_pg[0] = pp;

+		mc->mc_ki[0] = 0;

+		mc->mc_db->md_root = pp->mp_pgno;

+		DPRINTF(("root split! new root = %"Y"u", pp->mp_pgno));

+		new_root = mc->mc_db->md_depth++;

+

+		/* Add left (implicit) pointer. */

+		if ((rc = mdb_node_add(mc, 0, NULL, NULL, mp->mp_pgno, 0)) != MDB_SUCCESS) {

+			/* undo the pre-push */

+			mc->mc_pg[0] = mc->mc_pg[1];

+			mc->mc_ki[0] = mc->mc_ki[1];

+			mc->mc_db->md_root = mp->mp_pgno;

+			mc->mc_db->md_depth--;

+			goto done;

+		}

+		mc->mc_snum++;

+		mc->mc_top++;

+		ptop = 0;

+	} else {

+		ptop = mc->mc_top-1;

+		DPRINTF(("parent branch page is %"Y"u", mc->mc_pg[ptop]->mp_pgno));

+	}

+

+	mdb_cursor_copy(mc, &mn);

+	mn.mc_xcursor = NULL;

+	mn.mc_pg[mn.mc_top] = rp;

+	mn.mc_ki[ptop] = mc->mc_ki[ptop]+1;

+

+	if (nflags & MDB_APPEND) {

+		mn.mc_ki[mn.mc_top] = 0;

+		sepkey = *newkey;

+		split_indx = newindx;

+		nkeys = 0;

+	} else {

+

+		split_indx = (nkeys+1) / 2;

+

+		if (IS_LEAF2(rp)) {

+			char *split, *ins;

+			int x;

+			unsigned int lsize, rsize, ksize;

+			/* Move half of the keys to the right sibling */

+			x = mc->mc_ki[mc->mc_top] - split_indx;

+			ksize = mc->mc_db->md_pad;

+			split = LEAF2KEY(mp, split_indx, ksize);

+			rsize = (nkeys - split_indx) * ksize;

+			lsize = (nkeys - split_indx) * sizeof(indx_t);

+			mp->mp_lower -= lsize;

+			rp->mp_lower += lsize;

+			mp->mp_upper += rsize - lsize;

+			rp->mp_upper -= rsize - lsize;

+			sepkey.mv_size = ksize;

+			if (newindx == split_indx) {

+				sepkey.mv_data = newkey->mv_data;

+			} else {

+				sepkey.mv_data = split;

+			}

+			if (x<0) {

+				ins = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], ksize);

+				memcpy(rp->mp_ptrs, split, rsize);

+				sepkey.mv_data = rp->mp_ptrs;

+				memmove(ins+ksize, ins, (split_indx - mc->mc_ki[mc->mc_top]) * ksize);

+				memcpy(ins, newkey->mv_data, ksize);

+				mp->mp_lower += sizeof(indx_t);

+				mp->mp_upper -= ksize - sizeof(indx_t);

+			} else {

+				if (x)

+					memcpy(rp->mp_ptrs, split, x * ksize);

+				ins = LEAF2KEY(rp, x, ksize);

+				memcpy(ins, newkey->mv_data, ksize);

+				memcpy(ins+ksize, split + x * ksize, rsize - x * ksize);

+				rp->mp_lower += sizeof(indx_t);

+				rp->mp_upper -= ksize - sizeof(indx_t);

+				mc->mc_ki[mc->mc_top] = x;

+			}

+		} else {

+			int psize, nsize, k;

+			/* Maximum free space in an empty page */

+			pmax = env->me_psize - PAGEHDRSZ;

+			if (IS_LEAF(mp))

+				nsize = mdb_leaf_size(env, newkey, newdata);

+			else

+				nsize = mdb_branch_size(env, newkey);

+			nsize = EVEN(nsize);

+

+			/* grab a page to hold a temporary copy */

+			copy = mdb_page_malloc(mc->mc_txn, 1);

+			if (copy == NULL) {

+				rc = ENOMEM;

+				goto done;

+			}

+			copy->mp_pgno  = mp->mp_pgno;

+			copy->mp_flags = mp->mp_flags;

+			copy->mp_lower = (PAGEHDRSZ-PAGEBASE);

+			copy->mp_upper = env->me_psize - PAGEBASE;

+

+			/* prepare to insert */

+			for (i=0, j=0; i<nkeys; i++) {

+				if (i == newindx) {

+					copy->mp_ptrs[j++] = 0;

+				}

+				copy->mp_ptrs[j++] = mp->mp_ptrs[i];

+			}

+

+			/* When items are relatively large the split point needs

+			 * to be checked, because being off-by-one will make the

+			 * difference between success or failure in mdb_node_add.

+			 *

+			 * It's also relevant if a page happens to be laid out

+			 * such that one half of its nodes are all "small" and

+			 * the other half of its nodes are "large." If the new

+			 * item is also "large" and falls on the half with

+			 * "large" nodes, it also may not fit.

+			 *

+			 * As a final tweak, if the new item goes on the last

+			 * spot on the page (and thus, onto the new page), bias

+			 * the split so the new page is emptier than the old page.

+			 * This yields better packing during sequential inserts.

+			 */

+			if (nkeys < 20 || nsize > pmax/16 || newindx >= nkeys) {

+				/* Find split point */

+				psize = 0;

+				if (newindx <= split_indx || newindx >= nkeys) {

+					i = 0; j = 1;

+					k = newindx >= nkeys ? nkeys : split_indx+1+IS_LEAF(mp);

+				} else {

+					i = nkeys; j = -1;

+					k = split_indx-1;

+				}

+				for (; i!=k; i+=j) {

+					if (i == newindx) {

+						psize += nsize;

+						node = NULL;

+					} else {

+						node = (MDB_node *)((char *)mp + copy->mp_ptrs[i] + PAGEBASE);

+						psize += NODESIZE + NODEKSZ(node) + sizeof(indx_t);

+						if (IS_LEAF(mp)) {

+							if (F_ISSET(node->mn_flags, F_BIGDATA))

+								psize += sizeof(pgno_t);

+							else

+								psize += NODEDSZ(node);

+						}

+						psize = EVEN(psize);

+					}

+					if (psize > pmax || i == k-j) {

+						split_indx = i + (j<0);

+						break;

+					}

+				}

+			}

+			if (split_indx == newindx) {

+				sepkey.mv_size = newkey->mv_size;

+				sepkey.mv_data = newkey->mv_data;

+			} else {

+				node = (MDB_node *)((char *)mp + copy->mp_ptrs[split_indx] + PAGEBASE);

+				sepkey.mv_size = node->mn_ksize;

+				sepkey.mv_data = NODEKEY(node);

+			}

+		}

+	}

+

+	DPRINTF(("separator is %d [%s]", split_indx, DKEY(&sepkey)));

+

+	/* Copy separator key to the parent.

+	 */

+	if (SIZELEFT(mn.mc_pg[ptop]) < mdb_branch_size(env, &sepkey)) {

+		int snum = mc->mc_snum;

+		mn.mc_snum--;

+		mn.mc_top--;

+		did_split = 1;

+		/* We want other splits to find mn when doing fixups */

+		WITH_CURSOR_TRACKING(mn,

+			rc = mdb_page_split(&mn, &sepkey, NULL, rp->mp_pgno, 0));

+		if (rc)

+			goto done;

+

+		/* root split? */

+		if (mc->mc_snum > snum) {

+			ptop++;

+		}

+		/* Right page might now have changed parent.

+		 * Check if left page also changed parent.

+		 */

+		if (mn.mc_pg[ptop] != mc->mc_pg[ptop] &&

+		    mc->mc_ki[ptop] >= NUMKEYS(mc->mc_pg[ptop])) {

+			for (i=0; i<ptop; i++) {

+				mc->mc_pg[i] = mn.mc_pg[i];

+				mc->mc_ki[i] = mn.mc_ki[i];

+			}

+			mc->mc_pg[ptop] = mn.mc_pg[ptop];

+			if (mn.mc_ki[ptop]) {

+				mc->mc_ki[ptop] = mn.mc_ki[ptop] - 1;

+			} else {

+				/* find right page's left sibling */

+				mc->mc_ki[ptop] = mn.mc_ki[ptop];

+				mdb_cursor_sibling(mc, 0);

+			}

+		}

+	} else {

+		mn.mc_top--;

+		rc = mdb_node_add(&mn, mn.mc_ki[ptop], &sepkey, NULL, rp->mp_pgno, 0);

+		mn.mc_top++;

+	}

+	if (rc != MDB_SUCCESS) {

+		goto done;

+	}

+	if (nflags & MDB_APPEND) {

+		mc->mc_pg[mc->mc_top] = rp;

+		mc->mc_ki[mc->mc_top] = 0;

+		rc = mdb_node_add(mc, 0, newkey, newdata, newpgno, nflags);

+		if (rc)

+			goto done;

+		for (i=0; i<mc->mc_top; i++)

+			mc->mc_ki[i] = mn.mc_ki[i];

+	} else if (!IS_LEAF2(mp)) {

+		/* Move nodes */

+		mc->mc_pg[mc->mc_top] = rp;

+		i = split_indx;

+		j = 0;

+		do {

+			if (i == newindx) {

+				rkey.mv_data = newkey->mv_data;

+				rkey.mv_size = newkey->mv_size;

+				if (IS_LEAF(mp)) {

+					rdata = newdata;

+				} else

+					pgno = newpgno;

+				flags = nflags;

+				/* Update index for the new key. */

+				mc->mc_ki[mc->mc_top] = j;

+			} else {

+				node = (MDB_node *)((char *)mp + copy->mp_ptrs[i] + PAGEBASE);

+				rkey.mv_data = NODEKEY(node);

+				rkey.mv_size = node->mn_ksize;

+				if (IS_LEAF(mp)) {

+					xdata.mv_data = NODEDATA(node);

+					xdata.mv_size = NODEDSZ(node);

+					rdata = &xdata;

+				} else

+					pgno = NODEPGNO(node);

+				flags = node->mn_flags;

+			}

+

+			if (!IS_LEAF(mp) && j == 0) {

+				/* First branch index doesn't need key data. */

+				rkey.mv_size = 0;

+			}

+

+			rc = mdb_node_add(mc, j, &rkey, rdata, pgno, flags);

+			if (rc)

+				goto done;

+			if (i == nkeys) {

+				i = 0;

+				j = 0;

+				mc->mc_pg[mc->mc_top] = copy;

+			} else {

+				i++;

+				j++;

+			}

+		} while (i != split_indx);

+

+		nkeys = NUMKEYS(copy);

+		for (i=0; i<nkeys; i++)

+			mp->mp_ptrs[i] = copy->mp_ptrs[i];

+		mp->mp_lower = copy->mp_lower;

+		mp->mp_upper = copy->mp_upper;

+		memcpy(NODEPTR(mp, nkeys-1), NODEPTR(copy, nkeys-1),

+			env->me_psize - copy->mp_upper - PAGEBASE);

+

+		/* reset back to original page */

+		if (newindx < split_indx) {

+			mc->mc_pg[mc->mc_top] = mp;

+		} else {

+			mc->mc_pg[mc->mc_top] = rp;

+			mc->mc_ki[ptop]++;

+			/* Make sure mc_ki is still valid.

+			 */

+			if (mn.mc_pg[ptop] != mc->mc_pg[ptop] &&

+				mc->mc_ki[ptop] >= NUMKEYS(mc->mc_pg[ptop])) {

+				for (i=0; i<=ptop; i++) {

+					mc->mc_pg[i] = mn.mc_pg[i];

+					mc->mc_ki[i] = mn.mc_ki[i];

+				}

+			}

+		}

+		if (nflags & MDB_RESERVE) {

+			node = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);

+			if (!(node->mn_flags & F_BIGDATA))

+				newdata->mv_data = NODEDATA(node);

+		}

+	} else {

+		if (newindx >= split_indx) {

+			mc->mc_pg[mc->mc_top] = rp;

+			mc->mc_ki[ptop]++;

+			/* Make sure mc_ki is still valid.

+			 */

+			if (mn.mc_pg[ptop] != mc->mc_pg[ptop] &&

+				mc->mc_ki[ptop] >= NUMKEYS(mc->mc_pg[ptop])) {

+				for (i=0; i<=ptop; i++) {

+					mc->mc_pg[i] = mn.mc_pg[i];

+					mc->mc_ki[i] = mn.mc_ki[i];

+				}

+			}

+		}

+	}

+

+	{

+		/* Adjust other cursors pointing to mp */

+		MDB_cursor *m2, *m3;

+		MDB_dbi dbi = mc->mc_dbi;

+		nkeys = NUMKEYS(mp);

+

+		for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {

+			if (mc->mc_flags & C_SUB)

+				m3 = &m2->mc_xcursor->mx_cursor;

+			else

+				m3 = m2;

+			if (m3 == mc)

+				continue;

+			if (!(m2->mc_flags & m3->mc_flags & C_INITIALIZED))

+				continue;

+			if (new_root) {

+				int k;

+				/* sub cursors may be on different DB */

+				if (m3->mc_pg[0] != mp)

+					continue;

+				/* root split */

+				for (k=new_root; k>=0; k--) {

+					m3->mc_ki[k+1] = m3->mc_ki[k];

+					m3->mc_pg[k+1] = m3->mc_pg[k];

+				}

+				if (m3->mc_ki[0] >= nkeys) {

+					m3->mc_ki[0] = 1;

+				} else {

+					m3->mc_ki[0] = 0;

+				}

+				m3->mc_pg[0] = mc->mc_pg[0];

+				m3->mc_snum++;

+				m3->mc_top++;

+			}

+			if (m3->mc_top >= mc->mc_top && m3->mc_pg[mc->mc_top] == mp) {

+				if (m3->mc_ki[mc->mc_top] >= newindx && !(nflags & MDB_SPLIT_REPLACE))

+					m3->mc_ki[mc->mc_top]++;

+				if (m3->mc_ki[mc->mc_top] >= nkeys) {

+					m3->mc_pg[mc->mc_top] = rp;

+					m3->mc_ki[mc->mc_top] -= nkeys;

+					for (i=0; i<mc->mc_top; i++) {

+						m3->mc_ki[i] = mn.mc_ki[i];

+						m3->mc_pg[i] = mn.mc_pg[i];

+					}

+				}

+			} else if (!did_split && m3->mc_top >= ptop && m3->mc_pg[ptop] == mc->mc_pg[ptop] &&

+				m3->mc_ki[ptop] >= mc->mc_ki[ptop]) {

+				m3->mc_ki[ptop]++;

+			}

+			if (m3->mc_xcursor && (m3->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED) &&

+				IS_LEAF(mp)) {

+				MDB_node *node = NODEPTR(m3->mc_pg[mc->mc_top], m3->mc_ki[mc->mc_top]);

+				if ((node->mn_flags & (F_DUPDATA|F_SUBDATA)) == F_DUPDATA)

+					m3->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(node);

+			}

+		}

+	}

+	DPRINTF(("mp left: %d, rp left: %d", SIZELEFT(mp), SIZELEFT(rp)));

+

+done:

+	if (copy)					/* tmp page */

+		mdb_page_free(env, copy);

+	if (rc)

+		mc->mc_txn->mt_flags |= MDB_TXN_ERROR;

+	return rc;

+}

+

+int

+mdb_put(MDB_txn *txn, MDB_dbi dbi,

+    MDB_val *key, MDB_val *data, unsigned int flags)

+{

+	MDB_cursor mc;

+	MDB_xcursor mx;

+	int rc;

+

+	if (!key || !data || !TXN_DBI_EXIST(txn, dbi, DB_USRVALID))

+		return EINVAL;

+

+	if (flags & ~(MDB_NOOVERWRITE|MDB_NODUPDATA|MDB_RESERVE|MDB_APPEND|MDB_APPENDDUP))

+		return EINVAL;

+

+	if (txn->mt_flags & (MDB_TXN_RDONLY|MDB_TXN_BLOCKED))

+		return (txn->mt_flags & MDB_TXN_RDONLY) ? EACCES : MDB_BAD_TXN;

+

+	mdb_cursor_init(&mc, txn, dbi, &mx);

+	mc.mc_next = txn->mt_cursors[dbi];

+	txn->mt_cursors[dbi] = &mc;

+	rc = mdb_cursor_put(&mc, key, data, flags);

+	txn->mt_cursors[dbi] = mc.mc_next;

+	return rc;

+}

+

+#ifndef MDB_WBUF

+#define MDB_WBUF	(1024*1024)

+#endif

+

+	/** State needed for a compacting copy. */

+typedef struct mdb_copy {

+	pthread_mutex_t mc_mutex;

+	pthread_cond_t mc_cond;

+	char *mc_wbuf[2];

+	char *mc_over[2];

+	MDB_env *mc_env;

+	MDB_txn *mc_txn;

+	int mc_wlen[2];

+	int mc_olen[2];

+	pgno_t mc_next_pgno;

+	HANDLE mc_fd;

+	int mc_status;

+	volatile int mc_new;

+	int mc_toggle;

+

+} mdb_copy;

+

+	/** Dedicated writer thread for compacting copy. */

+static THREAD_RET ESECT CALL_CONV

+mdb_env_copythr(void *arg)

+{

+	mdb_copy *my = arg;

+	char *ptr;

+	int toggle = 0, wsize, rc;

+#ifdef _WIN32

+	DWORD len;

+#define DO_WRITE(rc, fd, ptr, w2, len)	rc = WriteFile(fd, ptr, w2, &len, NULL)

+#else

+	int len;

+#define DO_WRITE(rc, fd, ptr, w2, len)	len = write(fd, ptr, w2); rc = (len >= 0)

+#endif

+

+	pthread_mutex_lock(&my->mc_mutex);

+	my->mc_new = 0;

+	pthread_cond_signal(&my->mc_cond);

+	for(;;) {

+		while (!my->mc_new)

+			pthread_cond_wait(&my->mc_cond, &my->mc_mutex);

+		if (my->mc_new < 0) {

+			my->mc_new = 0;

+			break;

+		}

+		my->mc_new = 0;

+		wsize = my->mc_wlen[toggle];

+		ptr = my->mc_wbuf[toggle];

+again:

+		while (wsize > 0) {

+			DO_WRITE(rc, my->mc_fd, ptr, wsize, len);

+			if (!rc) {

+				rc = ErrCode();

+				break;

+			} else if (len > 0) {

+				rc = MDB_SUCCESS;

+				ptr += len;

+				wsize -= len;

+				continue;

+			} else {

+				rc = EIO;

+				break;

+			}

+		}

+		if (rc) {

+			my->mc_status = rc;

+			break;

+		}

+		/* If there's an overflow page tail, write it too */

+		if (my->mc_olen[toggle]) {

+			wsize = my->mc_olen[toggle];

+			ptr = my->mc_over[toggle];

+			my->mc_olen[toggle] = 0;

+			goto again;

+		}

+		my->mc_wlen[toggle] = 0;

+		toggle ^= 1;

+		pthread_cond_signal(&my->mc_cond);

+	}

+	pthread_cond_signal(&my->mc_cond);

+	pthread_mutex_unlock(&my->mc_mutex);

+	return (THREAD_RET)0;

+#undef DO_WRITE

+}

+

+	/** Tell the writer thread there's a buffer ready to write */

+static int ESECT

+mdb_env_cthr_toggle(mdb_copy *my, int st)

+{

+	int toggle = my->mc_toggle ^ 1;

+	pthread_mutex_lock(&my->mc_mutex);

+	if (my->mc_status) {

+		pthread_mutex_unlock(&my->mc_mutex);

+		return my->mc_status;

+	}

+	while (my->mc_new == 1)

+		pthread_cond_wait(&my->mc_cond, &my->mc_mutex);

+	my->mc_new = st;

+	my->mc_toggle = toggle;

+	pthread_cond_signal(&my->mc_cond);

+	pthread_mutex_unlock(&my->mc_mutex);

+	return 0;

+}

+

+	/** Depth-first tree traversal for compacting copy. */

+static int ESECT

+mdb_env_cwalk(mdb_copy *my, pgno_t *pg, int flags)

+{

+	MDB_cursor mc;

+	MDB_node *ni;

+	MDB_page *mo, *mp, *leaf;

+	char *buf, *ptr;

+	int rc, toggle;

+	unsigned int i;

+

+	/* Empty DB, nothing to do */

+	if (*pg == P_INVALID)

+		return MDB_SUCCESS;

+

+	mc.mc_snum = 1;

+	mc.mc_top = 0;

+	mc.mc_txn = my->mc_txn;

+

+	rc = mdb_page_get(&mc, *pg, &mc.mc_pg[0], NULL);

+	if (rc)

+		return rc;

+	rc = mdb_page_search_root(&mc, NULL, MDB_PS_FIRST);

+	if (rc)

+		return rc;

+

+	/* Make cursor pages writable */

+	buf = ptr = malloc(my->mc_env->me_psize * mc.mc_snum);

+	if (buf == NULL)

+		return ENOMEM;

+

+	for (i=0; i<mc.mc_top; i++) {

+		mdb_page_copy((MDB_page *)ptr, mc.mc_pg[i], my->mc_env->me_psize);

+		mc.mc_pg[i] = (MDB_page *)ptr;

+		ptr += my->mc_env->me_psize;

+	}

+

+	/* This is writable space for a leaf page. Usually not needed. */

+	leaf = (MDB_page *)ptr;

+

+	toggle = my->mc_toggle;

+	while (mc.mc_snum > 0) {

+		unsigned n;

+		mp = mc.mc_pg[mc.mc_top];

+		n = NUMKEYS(mp);

+

+		if (IS_LEAF(mp)) {

+			if (!IS_LEAF2(mp) && !(flags & F_DUPDATA)) {

+				for (i=0; i<n; i++) {

+					ni = NODEPTR(mp, i);

+					if (ni->mn_flags & F_BIGDATA) {

+						MDB_page *omp;

+						pgno_t pg;

+

+						/* Need writable leaf */

+						if (mp != leaf) {

+							mc.mc_pg[mc.mc_top] = leaf;

+							mdb_page_copy(leaf, mp, my->mc_env->me_psize);

+							mp = leaf;

+							ni = NODEPTR(mp, i);

+						}

+

+						memcpy(&pg, NODEDATA(ni), sizeof(pg));

+						rc = mdb_page_get(&mc, pg, &omp, NULL);

+						if (rc)

+							goto done;

+						if (my->mc_wlen[toggle] >= MDB_WBUF) {

+							rc = mdb_env_cthr_toggle(my, 1);

+							if (rc)

+								goto done;

+							toggle = my->mc_toggle;

+						}

+						mo = (MDB_page *)(my->mc_wbuf[toggle] + my->mc_wlen[toggle]);

+						memcpy(mo, omp, my->mc_env->me_psize);

+						mo->mp_pgno = my->mc_next_pgno;

+						my->mc_next_pgno += omp->mp_pages;

+						my->mc_wlen[toggle] += my->mc_env->me_psize;

+						if (omp->mp_pages > 1) {

+							my->mc_olen[toggle] = my->mc_env->me_psize * (omp->mp_pages - 1);

+							my->mc_over[toggle] = (char *)omp + my->mc_env->me_psize;

+							rc = mdb_env_cthr_toggle(my, 1);

+							if (rc)

+								goto done;

+							toggle = my->mc_toggle;

+						}

+						memcpy(NODEDATA(ni), &mo->mp_pgno, sizeof(pgno_t));

+					} else if (ni->mn_flags & F_SUBDATA) {

+						MDB_db db;

+

+						/* Need writable leaf */

+						if (mp != leaf) {

+							mc.mc_pg[mc.mc_top] = leaf;

+							mdb_page_copy(leaf, mp, my->mc_env->me_psize);

+							mp = leaf;

+							ni = NODEPTR(mp, i);

+						}

+

+						memcpy(&db, NODEDATA(ni), sizeof(db));

+						my->mc_toggle = toggle;

+						rc = mdb_env_cwalk(my, &db.md_root, ni->mn_flags & F_DUPDATA);

+						if (rc)

+							goto done;

+						toggle = my->mc_toggle;

+						memcpy(NODEDATA(ni), &db, sizeof(db));

+					}

+				}

+			}

+		} else {

+			mc.mc_ki[mc.mc_top]++;

+			if (mc.mc_ki[mc.mc_top] < n) {

+				pgno_t pg;

+again:

+				ni = NODEPTR(mp, mc.mc_ki[mc.mc_top]);

+				pg = NODEPGNO(ni);

+				rc = mdb_page_get(&mc, pg, &mp, NULL);

+				if (rc)

+					goto done;

+				mc.mc_top++;

+				mc.mc_snum++;

+				mc.mc_ki[mc.mc_top] = 0;

+				if (IS_BRANCH(mp)) {

+					/* Whenever we advance to a sibling branch page,

+					 * we must proceed all the way down to its first leaf.

+					 */

+					mdb_page_copy(mc.mc_pg[mc.mc_top], mp, my->mc_env->me_psize);

+					goto again;

+				} else

+					mc.mc_pg[mc.mc_top] = mp;

+				continue;

+			}

+		}

+		if (my->mc_wlen[toggle] >= MDB_WBUF) {

+			rc = mdb_env_cthr_toggle(my, 1);

+			if (rc)

+				goto done;

+			toggle = my->mc_toggle;

+		}

+		mo = (MDB_page *)(my->mc_wbuf[toggle] + my->mc_wlen[toggle]);

+		mdb_page_copy(mo, mp, my->mc_env->me_psize);

+		mo->mp_pgno = my->mc_next_pgno++;

+		my->mc_wlen[toggle] += my->mc_env->me_psize;

+		if (mc.mc_top) {

+			/* Update parent if there is one */

+			ni = NODEPTR(mc.mc_pg[mc.mc_top-1], mc.mc_ki[mc.mc_top-1]);

+			SETPGNO(ni, mo->mp_pgno);

+			mdb_cursor_pop(&mc);

+		} else {

+			/* Otherwise we're done */

+			*pg = mo->mp_pgno;

+			break;

+		}

+	}

+done:

+	free(buf);

+	return rc;

+}

+

+	/** Copy environment with compaction. */

+static int ESECT

+mdb_env_copyfd1(MDB_env *env, HANDLE fd)

+{

+	MDB_meta *mm;

+	MDB_page *mp;

+	mdb_copy my;

+	MDB_txn *txn = NULL;

+	pthread_t thr;

+	int rc;

+

+#ifdef _WIN32

+	my.mc_mutex = CreateMutex(NULL, FALSE, NULL);

+	my.mc_cond = CreateEvent(NULL, FALSE, FALSE, NULL);

+	my.mc_wbuf[0] = _aligned_malloc(MDB_WBUF*2, env->me_os_psize);

+	if (my.mc_wbuf[0] == NULL)

+		return errno;

+#else

+	pthread_mutex_init(&my.mc_mutex, NULL);

+	pthread_cond_init(&my.mc_cond, NULL);

+#ifdef HAVE_MEMALIGN

+	my.mc_wbuf[0] = memalign(env->me_os_psize, MDB_WBUF*2);

+	if (my.mc_wbuf[0] == NULL)

+		return errno;

+#else

+	rc = posix_memalign((void **)&my.mc_wbuf[0], env->me_os_psize, MDB_WBUF*2);

+	if (rc)

+		return rc;

+#endif

+#endif

+	memset(my.mc_wbuf[0], 0, MDB_WBUF*2);

+	my.mc_wbuf[1] = my.mc_wbuf[0] + MDB_WBUF;

+	my.mc_wlen[0] = 0;

+	my.mc_wlen[1] = 0;

+	my.mc_olen[0] = 0;

+	my.mc_olen[1] = 0;

+	my.mc_next_pgno = NUM_METAS;

+	my.mc_status = 0;

+	my.mc_new = 1;

+	my.mc_toggle = 0;

+	my.mc_env = env;

+	my.mc_fd = fd;

+	THREAD_CREATE(thr, mdb_env_copythr, &my);

+

+	rc = mdb_txn_begin(env, NULL, MDB_RDONLY, &txn);

+	if (rc)

+		return rc;

+

+	mp = (MDB_page *)my.mc_wbuf[0];

+	memset(mp, 0, NUM_METAS * env->me_psize);

+	mp->mp_pgno = 0;

+	mp->mp_flags = P_META;

+	mm = (MDB_meta *)METADATA(mp);

+	mdb_env_init_meta0(env, mm);

+	mm->mm_address = env->me_metas[0]->mm_address;

+

+	mp = (MDB_page *)(my.mc_wbuf[0] + env->me_psize);

+	mp->mp_pgno = 1;

+	mp->mp_flags = P_META;

+	*(MDB_meta *)METADATA(mp) = *mm;

+	mm = (MDB_meta *)METADATA(mp);

+

+	/* Count the number of free pages, subtract from lastpg to find

+	 * number of active pages

+	 */

+	{

+		MDB_ID freecount = 0;

+		MDB_cursor mc;

+		MDB_val key, data;

+		mdb_cursor_init(&mc, txn, FREE_DBI, NULL);

+		while ((rc = mdb_cursor_get(&mc, &key, &data, MDB_NEXT)) == 0)

+			freecount += *(MDB_ID *)data.mv_data;

+		freecount += txn->mt_dbs[FREE_DBI].md_branch_pages +

+			txn->mt_dbs[FREE_DBI].md_leaf_pages +

+			txn->mt_dbs[FREE_DBI].md_overflow_pages;

+

+		/* Set metapage 1 */

+		mm->mm_last_pg = txn->mt_next_pgno - freecount - 1;

+		mm->mm_dbs[MAIN_DBI] = txn->mt_dbs[MAIN_DBI];

+		if (mm->mm_last_pg > NUM_METAS-1) {

+			mm->mm_dbs[MAIN_DBI].md_root = mm->mm_last_pg;

+			mm->mm_txnid = 1;

+		} else {

+			mm->mm_dbs[MAIN_DBI].md_root = P_INVALID;

+		}

+	}

+	my.mc_wlen[0] = env->me_psize * NUM_METAS;

+	my.mc_txn = txn;

+	pthread_mutex_lock(&my.mc_mutex);

+	while(my.mc_new)

+		pthread_cond_wait(&my.mc_cond, &my.mc_mutex);

+	pthread_mutex_unlock(&my.mc_mutex);

+	rc = mdb_env_cwalk(&my, &txn->mt_dbs[MAIN_DBI].md_root, 0);

+	if (rc == MDB_SUCCESS && my.mc_wlen[my.mc_toggle])

+		rc = mdb_env_cthr_toggle(&my, 1);

+	mdb_env_cthr_toggle(&my, -1);

+	pthread_mutex_lock(&my.mc_mutex);

+	while(my.mc_new)

+		pthread_cond_wait(&my.mc_cond, &my.mc_mutex);

+	pthread_mutex_unlock(&my.mc_mutex);

+	THREAD_FINISH(thr);

+

+	mdb_txn_abort(txn);

+#ifdef _WIN32

+	CloseHandle(my.mc_cond);

+	CloseHandle(my.mc_mutex);

+	_aligned_free(my.mc_wbuf[0]);

+#else

+	pthread_cond_destroy(&my.mc_cond);

+	pthread_mutex_destroy(&my.mc_mutex);

+	free(my.mc_wbuf[0]);

+#endif

+	return rc;

+}

+

+	/** Copy environment as-is. */

+static int ESECT

+mdb_env_copyfd0(MDB_env *env, HANDLE fd)

+{

+	MDB_txn *txn = NULL;

+	mdb_mutexref_t wmutex = NULL;

+	int rc;

+	mdb_size_t wsize, w3;

+	char *ptr;

+#ifdef _WIN32

+	DWORD len, w2;

+#define DO_WRITE(rc, fd, ptr, w2, len)	rc = WriteFile(fd, ptr, w2, &len, NULL)

+#else

+	ssize_t len;

+	size_t w2;

+#define DO_WRITE(rc, fd, ptr, w2, len)	len = write(fd, ptr, w2); rc = (len >= 0)

+#endif

+

+	/* Do the lock/unlock of the reader mutex before starting the

+	 * write txn.  Otherwise other read txns could block writers.

+	 */

+	rc = mdb_txn_begin(env, NULL, MDB_RDONLY, &txn);

+	if (rc)

+		return rc;

+

+	if (env->me_txns) {

+		/* We must start the actual read txn after blocking writers */

+		mdb_txn_end(txn, MDB_END_RESET_TMP);

+

+		/* Temporarily block writers until we snapshot the meta pages */

+		wmutex = env->me_wmutex;

+		if (LOCK_MUTEX(rc, env, wmutex))

+			goto leave;

+

+		rc = mdb_txn_renew0(txn);

+		if (rc) {

+			UNLOCK_MUTEX(wmutex);

+			goto leave;

+		}

+	}

+

+	wsize = env->me_psize * NUM_METAS;

+	ptr = env->me_map;

+	w2 = wsize;

+	while (w2 > 0) {

+		DO_WRITE(rc, fd, ptr, w2, len);

+		if (!rc) {

+			rc = ErrCode();

+			break;

+		} else if (len > 0) {

+			rc = MDB_SUCCESS;

+			ptr += len;

+			w2 -= len;

+			continue;

+		} else {

+			/* Non-blocking or async handles are not supported */

+			rc = EIO;

+			break;

+		}

+	}

+	if (wmutex)

+		UNLOCK_MUTEX(wmutex);

+

+	if (rc)

+		goto leave;

+

+	w3 = txn->mt_next_pgno * env->me_psize;

+	{

+		mdb_size_t fsize = 0;

+		if ((rc = mdb_fsize(env->me_fd, &fsize)))

+			goto leave;

+		if (w3 > fsize)

+			w3 = fsize;

+	}

+	wsize = w3 - wsize;

+	while (wsize > 0) {

+		if (wsize > MAX_WRITE)

+			w2 = MAX_WRITE;

+		else

+			w2 = wsize;

+		DO_WRITE(rc, fd, ptr, w2, len);

+		if (!rc) {

+			rc = ErrCode();

+			break;

+		} else if (len > 0) {

+			rc = MDB_SUCCESS;

+			ptr += len;

+			wsize -= len;

+			continue;

+		} else {

+			rc = EIO;

+			break;

+		}

+	}

+

+leave:

+	mdb_txn_abort(txn);

+	return rc;

+}

+

+int ESECT

+mdb_env_copyfd2(MDB_env *env, HANDLE fd, unsigned int flags)

+{

+	if (flags & MDB_CP_COMPACT)

+		return mdb_env_copyfd1(env, fd);

+	else

+		return mdb_env_copyfd0(env, fd);

+}

+

+int ESECT

+mdb_env_copyfd(MDB_env *env, HANDLE fd)

+{

+	return mdb_env_copyfd2(env, fd, 0);

+}

+

+int ESECT

+mdb_env_copy2(MDB_env *env, const char *path, unsigned int flags)

+{

+	int rc, len;

+	char *lpath;

+	HANDLE newfd = INVALID_HANDLE_VALUE;

+#ifdef _WIN32

+	wchar_t *wpath;

+#endif

+

+	if (env->me_flags & MDB_NOSUBDIR) {

+		lpath = (char *)path;

+	} else {

+		len = strlen(path);

+		len += sizeof(DATANAME);

+		lpath = malloc(len);

+		if (!lpath)

+			return ENOMEM;

+		sprintf(lpath, "%s" DATANAME, path);

+	}

+

+	/* The destination path must exist, but the destination file must not.

+	 * We don't want the OS to cache the writes, since the source data is

+	 * already in the OS cache.

+	 */

+#ifdef _WIN32

+	rc = utf8_to_utf16(lpath, -1, &wpath, NULL);

+	if (rc)

+		goto leave;

+	newfd = CreateFileW(wpath, GENERIC_WRITE, 0, NULL, CREATE_NEW,

+				FILE_FLAG_NO_BUFFERING|FILE_FLAG_WRITE_THROUGH, NULL);

+	free(wpath);

+#else

+	newfd = open(lpath, O_WRONLY|O_CREAT|O_EXCL, 0666);

+#endif

+	if (newfd == INVALID_HANDLE_VALUE) {

+		rc = ErrCode();

+		goto leave;

+	}

+

+	if (env->me_psize >= env->me_os_psize) {

+#ifdef O_DIRECT

+	/* Set O_DIRECT if the file system supports it */

+	if ((rc = fcntl(newfd, F_GETFL)) != -1)

+		(void) fcntl(newfd, F_SETFL, rc | O_DIRECT);

+#endif

+#ifdef F_NOCACHE	/* __APPLE__ */

+	rc = fcntl(newfd, F_NOCACHE, 1);

+	if (rc) {

+		rc = ErrCode();

+		goto leave;

+	}

+#endif

+	}

+

+	rc = mdb_env_copyfd2(env, newfd, flags);

+

+leave:

+	if (!(env->me_flags & MDB_NOSUBDIR))

+		free(lpath);

+	if (newfd != INVALID_HANDLE_VALUE)

+		if (close(newfd) < 0 && rc == MDB_SUCCESS)

+			rc = ErrCode();

+

+	return rc;

+}

+

+int ESECT

+mdb_env_copy(MDB_env *env, const char *path)

+{

+	return mdb_env_copy2(env, path, 0);

+}

+

+int ESECT

+mdb_env_set_flags(MDB_env *env, unsigned int flag, int onoff)

+{

+	if (flag & ~CHANGEABLE)

+		return EINVAL;

+	if (onoff)

+		env->me_flags |= flag;

+	else

+		env->me_flags &= ~flag;

+	return MDB_SUCCESS;

+}

+

+int ESECT

+mdb_env_get_flags(MDB_env *env, unsigned int *arg)

+{

+	if (!env || !arg)

+		return EINVAL;

+

+	*arg = env->me_flags & (CHANGEABLE|CHANGELESS);

+	return MDB_SUCCESS;

+}

+

+int ESECT

+mdb_env_set_userctx(MDB_env *env, void *ctx)

+{

+	if (!env)

+		return EINVAL;

+	env->me_userctx = ctx;

+	return MDB_SUCCESS;

+}

+

+void * ESECT

+mdb_env_get_userctx(MDB_env *env)

+{

+	return env ? env->me_userctx : NULL;

+}

+

+int ESECT

+mdb_env_set_assert(MDB_env *env, MDB_assert_func *func)

+{

+	if (!env)

+		return EINVAL;

+#ifndef NDEBUG

+	env->me_assert_func = func;

+#endif

+	return MDB_SUCCESS;

+}

+

+int ESECT

+mdb_env_get_path(MDB_env *env, const char **arg)

+{

+	if (!env || !arg)

+		return EINVAL;

+

+	*arg = env->me_path;

+	return MDB_SUCCESS;

+}

+

+int ESECT

+mdb_env_get_fd(MDB_env *env, mdb_filehandle_t *arg)

+{

+	if (!env || !arg)

+		return EINVAL;

+

+	*arg = env->me_fd;

+	return MDB_SUCCESS;

+}

+

+/** Common code for #mdb_stat() and #mdb_env_stat().

+ * @param[in] env the environment to operate in.

+ * @param[in] db the #MDB_db record containing the stats to return.

+ * @param[out] arg the address of an #MDB_stat structure to receive the stats.

+ * @return 0, this function always succeeds.

+ */

+static int ESECT

+mdb_stat0(MDB_env *env, MDB_db *db, MDB_stat *arg)

+{

+	arg->ms_psize = env->me_psize;

+	arg->ms_depth = db->md_depth;

+	arg->ms_branch_pages = db->md_branch_pages;

+	arg->ms_leaf_pages = db->md_leaf_pages;

+	arg->ms_overflow_pages = db->md_overflow_pages;

+	arg->ms_entries = db->md_entries;

+

+	return MDB_SUCCESS;

+}

+

+int ESECT

+mdb_env_stat(MDB_env *env, MDB_stat *arg)

+{

+	MDB_meta *meta;

+

+	if (env == NULL || arg == NULL)

+		return EINVAL;

+

+	meta = mdb_env_pick_meta(env);

+

+	return mdb_stat0(env, &meta->mm_dbs[MAIN_DBI], arg);

+}

+

+int ESECT

+mdb_env_info(MDB_env *env, MDB_envinfo *arg)

+{

+	MDB_meta *meta;

+

+	if (env == NULL || arg == NULL)

+		return EINVAL;

+

+	meta = mdb_env_pick_meta(env);

+	arg->me_mapaddr = meta->mm_address;

+	arg->me_last_pgno = meta->mm_last_pg;

+	arg->me_last_txnid = meta->mm_txnid;

+

+	arg->me_mapsize = env->me_mapsize;

+	arg->me_maxreaders = env->me_maxreaders;

+	arg->me_numreaders = env->me_txns ? env->me_txns->mti_numreaders : 0;

+	return MDB_SUCCESS;

+}

+

+/** Set the default comparison functions for a database.

+ * Called immediately after a database is opened to set the defaults.

+ * The user can then override them with #mdb_set_compare() or

+ * #mdb_set_dupsort().

+ * @param[in] txn A transaction handle returned by #mdb_txn_begin()

+ * @param[in] dbi A database handle returned by #mdb_dbi_open()

+ */

+static void

+mdb_default_cmp(MDB_txn *txn, MDB_dbi dbi)

+{

+	uint16_t f = txn->mt_dbs[dbi].md_flags;

+

+	txn->mt_dbxs[dbi].md_cmp =

+		(f & MDB_REVERSEKEY) ? mdb_cmp_memnr :

+		(f & MDB_INTEGERKEY) ? mdb_cmp_cint  : mdb_cmp_memn;

+

+	txn->mt_dbxs[dbi].md_dcmp =

+		!(f & MDB_DUPSORT) ? 0 :

+		((f & MDB_INTEGERDUP)

+		 ? ((f & MDB_DUPFIXED)   ? mdb_cmp_int   : mdb_cmp_cint)

+		 : ((f & MDB_REVERSEDUP) ? mdb_cmp_memnr : mdb_cmp_memn));

+}

+

+int mdb_dbi_open(MDB_txn *txn, const char *name, unsigned int flags, MDB_dbi *dbi)

+{

+	MDB_val key, data;

+	MDB_dbi i;

+	MDB_cursor mc;

+	MDB_db dummy;

+	int rc, dbflag, exact;

+	unsigned int unused = 0, seq;

+	char *namedup;

+	size_t len;

+

+	if (flags & ~VALID_FLAGS)

+		return EINVAL;

+	if (txn->mt_flags & MDB_TXN_BLOCKED)

+		return MDB_BAD_TXN;

+

+	/* main DB? */

+	if (!name) {

+		*dbi = MAIN_DBI;

+		if (flags & PERSISTENT_FLAGS) {

+			uint16_t f2 = flags & PERSISTENT_FLAGS;

+			/* make sure flag changes get committed */

+			if ((txn->mt_dbs[MAIN_DBI].md_flags | f2) != txn->mt_dbs[MAIN_DBI].md_flags) {

+				txn->mt_dbs[MAIN_DBI].md_flags |= f2;

+				txn->mt_flags |= MDB_TXN_DIRTY;

+			}

+		}

+		mdb_default_cmp(txn, MAIN_DBI);

+		return MDB_SUCCESS;

+	}

+

+	if (txn->mt_dbxs[MAIN_DBI].md_cmp == NULL) {

+		mdb_default_cmp(txn, MAIN_DBI);

+	}

+

+	/* Is the DB already open? */

+	len = strlen(name);

+	for (i=CORE_DBS; i<txn->mt_numdbs; i++) {

+		if (!txn->mt_dbxs[i].md_name.mv_size) {

+			/* Remember this free slot */

+			if (!unused) unused = i;

+			continue;

+		}

+		if (len == txn->mt_dbxs[i].md_name.mv_size &&

+			!strncmp(name, txn->mt_dbxs[i].md_name.mv_data, len)) {

+			*dbi = i;

+			return MDB_SUCCESS;

+		}

+	}

+

+	/* If no free slot and max hit, fail */

+	if (!unused && txn->mt_numdbs >= txn->mt_env->me_maxdbs)

+		return MDB_DBS_FULL;

+

+	/* Cannot mix named databases with some mainDB flags */

+	if (txn->mt_dbs[MAIN_DBI].md_flags & (MDB_DUPSORT|MDB_INTEGERKEY))

+		return (flags & MDB_CREATE) ? MDB_INCOMPATIBLE : MDB_NOTFOUND;

+

+	/* Find the DB info */

+	dbflag = DB_NEW|DB_VALID|DB_USRVALID;

+	exact = 0;

+	key.mv_size = len;

+	key.mv_data = (void *)name;

+	mdb_cursor_init(&mc, txn, MAIN_DBI, NULL);

+	rc = mdb_cursor_set(&mc, &key, &data, MDB_SET, &exact);

+	if (rc == MDB_SUCCESS) {

+		/* make sure this is actually a DB */

+		MDB_node *node = NODEPTR(mc.mc_pg[mc.mc_top], mc.mc_ki[mc.mc_top]);

+		if ((node->mn_flags & (F_DUPDATA|F_SUBDATA)) != F_SUBDATA)

+			return MDB_INCOMPATIBLE;

+	} else if (! (rc == MDB_NOTFOUND && (flags & MDB_CREATE))) {

+		return rc;

+	}

+

+	/* Done here so we cannot fail after creating a new DB */

+	if ((namedup = strdup(name)) == NULL)

+		return ENOMEM;

+

+	if (rc) {

+		/* MDB_NOTFOUND and MDB_CREATE: Create new DB */

+		data.mv_size = sizeof(MDB_db);

+		data.mv_data = &dummy;

+		memset(&dummy, 0, sizeof(dummy));

+		dummy.md_root = P_INVALID;

+		dummy.md_flags = flags & PERSISTENT_FLAGS;

+		rc = mdb_cursor_put(&mc, &key, &data, F_SUBDATA);

+		dbflag |= DB_DIRTY;

+	}

+

+	if (rc) {

+		free(namedup);

+	} else {

+		/* Got info, register DBI in this txn */

+		unsigned int slot = unused ? unused : txn->mt_numdbs;

+		txn->mt_dbxs[slot].md_name.mv_data = namedup;

+		txn->mt_dbxs[slot].md_name.mv_size = len;

+		txn->mt_dbxs[slot].md_rel = NULL;

+		txn->mt_dbflags[slot] = dbflag;

+		/* txn-> and env-> are the same in read txns, use

+		 * tmp variable to avoid undefined assignment

+		 */

+		seq = ++txn->mt_env->me_dbiseqs[slot];

+		txn->mt_dbiseqs[slot] = seq;

+

+		memcpy(&txn->mt_dbs[slot], data.mv_data, sizeof(MDB_db));

+		*dbi = slot;

+		mdb_default_cmp(txn, slot);

+		if (!unused) {

+			txn->mt_numdbs++;

+		}

+	}

+

+	return rc;

+}

+

+int ESECT

+mdb_stat(MDB_txn *txn, MDB_dbi dbi, MDB_stat *arg)

+{

+	if (!arg || !TXN_DBI_EXIST(txn, dbi, DB_VALID))

+		return EINVAL;

+

+	if (txn->mt_flags & MDB_TXN_BLOCKED)

+		return MDB_BAD_TXN;

+

+	if (txn->mt_dbflags[dbi] & DB_STALE) {

+		MDB_cursor mc;

+		MDB_xcursor mx;

+		/* Stale, must read the DB's root. cursor_init does it for us. */

+		mdb_cursor_init(&mc, txn, dbi, &mx);

+	}

+	return mdb_stat0(txn->mt_env, &txn->mt_dbs[dbi], arg);

+}

+

+void mdb_dbi_close(MDB_env *env, MDB_dbi dbi)

+{

+	char *ptr;

+	if (dbi < CORE_DBS || dbi >= env->me_maxdbs)

+		return;

+	ptr = env->me_dbxs[dbi].md_name.mv_data;

+	/* If there was no name, this was already closed */

+	if (ptr) {

+		env->me_dbxs[dbi].md_name.mv_data = NULL;

+		env->me_dbxs[dbi].md_name.mv_size = 0;

+		env->me_dbflags[dbi] = 0;

+		env->me_dbiseqs[dbi]++;

+		free(ptr);

+	}

+}

+

+int mdb_dbi_flags(MDB_txn *txn, MDB_dbi dbi, unsigned int *flags)

+{

+	/* We could return the flags for the FREE_DBI too but what's the point? */

+	if (!TXN_DBI_EXIST(txn, dbi, DB_USRVALID))

+		return EINVAL;

+	*flags = txn->mt_dbs[dbi].md_flags & PERSISTENT_FLAGS;

+	return MDB_SUCCESS;

+}

+

+/** Add all the DB's pages to the free list.

+ * @param[in] mc Cursor on the DB to free.

+ * @param[in] subs non-Zero to check for sub-DBs in this DB.

+ * @return 0 on success, non-zero on failure.

+ */

+static int

+mdb_drop0(MDB_cursor *mc, int subs)

+{

+	int rc;

+

+	rc = mdb_page_search(mc, NULL, MDB_PS_FIRST);

+	if (rc == MDB_SUCCESS) {

+		MDB_txn *txn = mc->mc_txn;

+		MDB_node *ni;

+		MDB_cursor mx;

+		unsigned int i;

+

+		/* DUPSORT sub-DBs have no ovpages/DBs. Omit scanning leaves.

+		 * This also avoids any P_LEAF2 pages, which have no nodes.

+		 * Also if the DB doesn't have sub-DBs and has no overflow

+		 * pages, omit scanning leaves.

+		 */

+		if ((mc->mc_flags & C_SUB) ||

+			(!subs && !mc->mc_db->md_overflow_pages))

+			mdb_cursor_pop(mc);

+

+		mdb_cursor_copy(mc, &mx);

+#ifdef MDB_VL32

+		/* bump refcount for mx's pages */

+		for (i=0; i<mc->mc_snum; i++)

+			mdb_page_get(&mx, mc->mc_pg[i]->mp_pgno, &mx.mc_pg[i], NULL);

+#endif

+		while (mc->mc_snum > 0) {

+			MDB_page *mp = mc->mc_pg[mc->mc_top];

+			unsigned n = NUMKEYS(mp);

+			if (IS_LEAF(mp)) {

+				for (i=0; i<n; i++) {

+					ni = NODEPTR(mp, i);

+					if (ni->mn_flags & F_BIGDATA) {

+						MDB_page *omp;

+						pgno_t pg;

+						memcpy(&pg, NODEDATA(ni), sizeof(pg));

+						rc = mdb_page_get(mc, pg, &omp, NULL);

+						if (rc != 0)

+							goto done;

+						mdb_cassert(mc, IS_OVERFLOW(omp));

+						rc = mdb_midl_append_range(&txn->mt_free_pgs,

+							pg, omp->mp_pages);

+						if (rc)

+							goto done;

+						mc->mc_db->md_overflow_pages -= omp->mp_pages;

+						if (!mc->mc_db->md_overflow_pages && !subs)

+							break;

+					} else if (subs && (ni->mn_flags & F_SUBDATA)) {

+						mdb_xcursor_init1(mc, ni);

+						rc = mdb_drop0(&mc->mc_xcursor->mx_cursor, 0);

+						if (rc)

+							goto done;

+					}

+				}

+				if (!subs && !mc->mc_db->md_overflow_pages)

+					goto pop;

+			} else {

+				if ((rc = mdb_midl_need(&txn->mt_free_pgs, n)) != 0)

+					goto done;

+				for (i=0; i<n; i++) {

+					pgno_t pg;

+					ni = NODEPTR(mp, i);

+					pg = NODEPGNO(ni);

+					/* free it */

+					mdb_midl_xappend(txn->mt_free_pgs, pg);

+				}

+			}

+			if (!mc->mc_top)

+				break;

+			mc->mc_ki[mc->mc_top] = i;

+			rc = mdb_cursor_sibling(mc, 1);

+			if (rc) {

+				if (rc != MDB_NOTFOUND)

+					goto done;

+				/* no more siblings, go back to beginning

+				 * of previous level.

+				 */

+pop:

+				mdb_cursor_pop(mc);

+				mc->mc_ki[0] = 0;

+				for (i=1; i<mc->mc_snum; i++) {

+					mc->mc_ki[i] = 0;

+					mc->mc_pg[i] = mx.mc_pg[i];

+				}

+			}

+		}

+		/* free it */

+		rc = mdb_midl_append(&txn->mt_free_pgs, mc->mc_db->md_root);

+done:

+		if (rc)

+			txn->mt_flags |= MDB_TXN_ERROR;

+#ifdef MDB_VL32

+		/* drop refcount for mx's pages */

+		mdb_cursor_unref(&mx);

+#endif

+	} else if (rc == MDB_NOTFOUND) {

+		rc = MDB_SUCCESS;

+	}

+	mc->mc_flags &= ~C_INITIALIZED;

+	return rc;

+}

+

+int mdb_drop(MDB_txn *txn, MDB_dbi dbi, int del)

+{

+	MDB_cursor *mc, *m2;

+	int rc;

+

+	if ((unsigned)del > 1 || !TXN_DBI_EXIST(txn, dbi, DB_USRVALID))

+		return EINVAL;

+

+	if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY))

+		return EACCES;

+

+	if (TXN_DBI_CHANGED(txn, dbi))

+		return MDB_BAD_DBI;

+

+	rc = mdb_cursor_open(txn, dbi, &mc);

+	if (rc)

+		return rc;

+

+	rc = mdb_drop0(mc, mc->mc_db->md_flags & MDB_DUPSORT);

+	/* Invalidate the dropped DB's cursors */

+	for (m2 = txn->mt_cursors[dbi]; m2; m2 = m2->mc_next)

+		m2->mc_flags &= ~(C_INITIALIZED|C_EOF);

+	if (rc)

+		goto leave;

+

+	/* Can't delete the main DB */

+	if (del && dbi >= CORE_DBS) {

+		rc = mdb_del0(txn, MAIN_DBI, &mc->mc_dbx->md_name, NULL, F_SUBDATA);

+		if (!rc) {

+			txn->mt_dbflags[dbi] = DB_STALE;

+			mdb_dbi_close(txn->mt_env, dbi);

+		} else {

+			txn->mt_flags |= MDB_TXN_ERROR;

+		}

+	} else {

+		/* reset the DB record, mark it dirty */

+		txn->mt_dbflags[dbi] |= DB_DIRTY;

+		txn->mt_dbs[dbi].md_depth = 0;

+		txn->mt_dbs[dbi].md_branch_pages = 0;

+		txn->mt_dbs[dbi].md_leaf_pages = 0;

+		txn->mt_dbs[dbi].md_overflow_pages = 0;

+		txn->mt_dbs[dbi].md_entries = 0;

+		txn->mt_dbs[dbi].md_root = P_INVALID;

+

+		txn->mt_flags |= MDB_TXN_DIRTY;

+	}

+leave:

+	mdb_cursor_close(mc);

+	return rc;

+}

+

+int mdb_set_compare(MDB_txn *txn, MDB_dbi dbi, MDB_cmp_func *cmp)

+{

+	if (!TXN_DBI_EXIST(txn, dbi, DB_USRVALID))

+		return EINVAL;

+

+	txn->mt_dbxs[dbi].md_cmp = cmp;

+	return MDB_SUCCESS;

+}

+

+int mdb_set_dupsort(MDB_txn *txn, MDB_dbi dbi, MDB_cmp_func *cmp)

+{

+	if (!TXN_DBI_EXIST(txn, dbi, DB_USRVALID))

+		return EINVAL;

+

+	txn->mt_dbxs[dbi].md_dcmp = cmp;

+	return MDB_SUCCESS;

+}

+

+int mdb_set_relfunc(MDB_txn *txn, MDB_dbi dbi, MDB_rel_func *rel)

+{

+	if (!TXN_DBI_EXIST(txn, dbi, DB_USRVALID))

+		return EINVAL;

+

+	txn->mt_dbxs[dbi].md_rel = rel;

+	return MDB_SUCCESS;

+}

+

+int mdb_set_relctx(MDB_txn *txn, MDB_dbi dbi, void *ctx)

+{

+	if (!TXN_DBI_EXIST(txn, dbi, DB_USRVALID))

+		return EINVAL;

+

+	txn->mt_dbxs[dbi].md_relctx = ctx;

+	return MDB_SUCCESS;

+}

+

+int ESECT

+mdb_env_get_maxkeysize(MDB_env *env)

+{

+	return ENV_MAXKEY(env);

+}

+

+int ESECT

+mdb_reader_list(MDB_env *env, MDB_msg_func *func, void *ctx)

+{

+	unsigned int i, rdrs;

+	MDB_reader *mr;

+	char buf[64];

+	int rc = 0, first = 1;

+

+	if (!env || !func)

+		return -1;

+	if (!env->me_txns) {

+		return func("(no reader locks)\n", ctx);

+	}

+	rdrs = env->me_txns->mti_numreaders;

+	mr = env->me_txns->mti_readers;

+	for (i=0; i<rdrs; i++) {

+		if (mr[i].mr_pid) {

+			txnid_t	txnid = mr[i].mr_txnid;

+			sprintf(buf, txnid == (txnid_t)-1 ?

+				"%10d %"Z"x -\n" : "%10d %"Z"x %"Y"u\n",

+				(int)mr[i].mr_pid, (size_t)mr[i].mr_tid, txnid);

+			if (first) {

+				first = 0;

+				rc = func("    pid     thread     txnid\n", ctx);

+				if (rc < 0)

+					break;

+			}

+			rc = func(buf, ctx);

+			if (rc < 0)

+				break;

+		}

+	}

+	if (first) {

+		rc = func("(no active readers)\n", ctx);

+	}

+	return rc;

+}

+

+/** Insert pid into list if not already present.

+ * return -1 if already present.

+ */

+static int ESECT

+mdb_pid_insert(MDB_PID_T *ids, MDB_PID_T pid)

+{

+	/* binary search of pid in list */

+	unsigned base = 0;

+	unsigned cursor = 1;

+	int val = 0;

+	unsigned n = ids[0];

+

+	while( 0 < n ) {

+		unsigned pivot = n >> 1;

+		cursor = base + pivot + 1;

+		val = pid - ids[cursor];

+

+		if( val < 0 ) {

+			n = pivot;

+

+		} else if ( val > 0 ) {

+			base = cursor;

+			n -= pivot + 1;

+

+		} else {

+			/* found, so it's a duplicate */

+			return -1;

+		}

+	}

+

+	if( val > 0 ) {

+		++cursor;

+	}

+	ids[0]++;

+	for (n = ids[0]; n > cursor; n--)

+		ids[n] = ids[n-1];

+	ids[n] = pid;

+	return 0;

+}

+

+int ESECT

+mdb_reader_check(MDB_env *env, int *dead)

+{

+	if (!env)

+		return EINVAL;

+	if (dead)

+		*dead = 0;

+	return env->me_txns ? mdb_reader_check0(env, 0, dead) : MDB_SUCCESS;

+}

+

+/** As #mdb_reader_check(). rlocked = <caller locked the reader mutex>. */

+static int ESECT

+mdb_reader_check0(MDB_env *env, int rlocked, int *dead)

+{

+	mdb_mutexref_t rmutex = rlocked ? NULL : env->me_rmutex;

+	unsigned int i, j, rdrs;

+	MDB_reader *mr;

+	MDB_PID_T *pids, pid;

+	int rc = MDB_SUCCESS, count = 0;

+

+	rdrs = env->me_txns->mti_numreaders;

+	pids = malloc((rdrs+1) * sizeof(MDB_PID_T));

+	if (!pids)

+		return ENOMEM;

+	pids[0] = 0;

+	mr = env->me_txns->mti_readers;

+	for (i=0; i<rdrs; i++) {

+		pid = mr[i].mr_pid;

+		if (pid && pid != env->me_pid) {

+			if (mdb_pid_insert(pids, pid) == 0) {

+				if (!mdb_reader_pid(env, Pidcheck, pid)) {

+					/* Stale reader found */

+					j = i;

+					if (rmutex) {

+						if ((rc = LOCK_MUTEX0(rmutex)) != 0) {

+							if ((rc = mdb_mutex_failed(env, rmutex, rc)))

+								break;

+							rdrs = 0; /* the above checked all readers */

+						} else {

+							/* Recheck, a new process may have reused pid */

+							if (mdb_reader_pid(env, Pidcheck, pid))

+								j = rdrs;

+						}

+					}

+					for (; j<rdrs; j++)

+							if (mr[j].mr_pid == pid) {

+								DPRINTF(("clear stale reader pid %u txn %"Y"d",

+									(unsigned) pid, mr[j].mr_txnid));

+								mr[j].mr_pid = 0;

+								count++;

+							}

+					if (rmutex)

+						UNLOCK_MUTEX(rmutex);

+				}

+			}

+		}

+	}

+	free(pids);

+	if (dead)

+		*dead = count;

+	return rc;

+}

+

+#ifdef MDB_ROBUST_SUPPORTED

+/** Handle #LOCK_MUTEX0() failure.

+ * Try to repair the lock file if the mutex owner died.

+ * @param[in] env	the environment handle

+ * @param[in] mutex	LOCK_MUTEX0() mutex

+ * @param[in] rc	LOCK_MUTEX0() error (nonzero)

+ * @return 0 on success with the mutex locked, or an error code on failure.

+ */

+static int ESECT

+mdb_mutex_failed(MDB_env *env, mdb_mutexref_t mutex, int rc)

+{

+	int rlocked, rc2;

+	MDB_meta *meta;

+

+	if (rc == MDB_OWNERDEAD) {

+		/* We own the mutex. Clean up after dead previous owner. */

+		rc = MDB_SUCCESS;

+		rlocked = (mutex == env->me_rmutex);

+		if (!rlocked) {

+			/* Keep mti_txnid updated, otherwise next writer can

+			 * overwrite data which latest meta page refers to.

+			 */

+			meta = mdb_env_pick_meta(env);

+			env->me_txns->mti_txnid = meta->mm_txnid;

+			/* env is hosed if the dead thread was ours */

+			if (env->me_txn) {

+				env->me_flags |= MDB_FATAL_ERROR;

+				env->me_txn = NULL;

+				rc = MDB_PANIC;

+			}

+		}

+		DPRINTF(("%cmutex owner died, %s", (rlocked ? 'r' : 'w'),

+			(rc ? "this process' env is hosed" : "recovering")));

+		rc2 = mdb_reader_check0(env, rlocked, NULL);

+		if (rc2 == 0)

+			rc2 = mdb_mutex_consistent(mutex);

+		if (rc || (rc = rc2)) {

+			DPRINTF(("LOCK_MUTEX recovery failed, %s", mdb_strerror(rc)));

+			UNLOCK_MUTEX(mutex);

+		}

+	} else {

+#ifdef _WIN32

+		rc = ErrCode();

+#endif

+		DPRINTF(("LOCK_MUTEX failed, %s", mdb_strerror(rc)));

+	}

+

+	return rc;

+}

+#endif	/* MDB_ROBUST_SUPPORTED */

+/** @} */

+

+#if defined(_WIN32)

+static int utf8_to_utf16(const char *src, int srcsize, wchar_t **dst, int *dstsize)

+{

+	int need;

+	wchar_t *result;

+	need = MultiByteToWideChar(CP_UTF8, 0, src, srcsize, NULL, 0);

+	if (need == 0xFFFD)

+		return EILSEQ;

+	if (need == 0)

+		return EINVAL;

+	result = malloc(sizeof(wchar_t) * need);

+	if (!result)

+		return ENOMEM;

+	MultiByteToWideChar(CP_UTF8, 0, src, srcsize, result, need);

+	if (dstsize)

+		*dstsize = need;

+	*dst = result;

+	return 0;

+}

+#endif /* defined(_WIN32) */