From 209b56fead1afe8273db6c714c0a74a9c09b9cf6 Mon Sep 17 00:00:00 2001
From: Howard Chu <hyc@openldap.org>
Date: Mon, 21 Dec 2015 02:36:20 +0000
Subject: [PATCH] ITS#8324 fix for WRITEMAP

We called FlushViewOfFile with (map,mapsize) which worked fine
when we had allocated the entire map already. Now we have to make
sure to only flush as much as was actually written. Add a numpgs
argument to tell how much to flush in env_sync0().
---
 libraries/liblmdb/mdb.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/libraries/liblmdb/mdb.c b/libraries/liblmdb/mdb.c
index c6a6802..a02ce5c 100644
--- a/libraries/liblmdb/mdb.c
+++ b/libraries/liblmdb/mdb.c
@@ -2643,7 +2643,7 @@ fail:
 }
 
 int
-mdb_env_sync(MDB_env *env, int force)
+mdb_env_sync0(MDB_env *env, int force, pgno_t numpgs)
 {
 	int rc = 0;
 	if (env->me_flags & MDB_RDONLY)
@@ -2652,7 +2652,7 @@ mdb_env_sync(MDB_env *env, int force)
 		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_mapsize, flags))
+			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))
@@ -2672,6 +2672,13 @@ mdb_env_sync(MDB_env *env, int force)
 	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)
@@ -3813,7 +3820,7 @@ mdb_txn_commit(MDB_txn *txn)
 	if ((rc = mdb_page_flush(txn, 0)))
 		goto fail;
 	if (!F_ISSET(txn->mt_flags, MDB_TXN_NOSYNC) &&
-		(rc = mdb_env_sync(env, 0)))
+		(rc = mdb_env_sync0(env, 0, txn->mt_next_pgno)))
 		goto fail;
 	if ((rc = mdb_env_write_meta(txn)))
 		goto fail;