Revert ITS#7789 commits, let's try this again.

Revert "ITS#7789 Fix resize vs MDB_NOMETASYNC, and a comment."
Revert "ITS#7789 more"
Revert "Revert "ITS#7789 update RESIZED errmsg text""
Revert "ITS#7789 update RESIZED errmsg text"
Revert "ITS#7789 persist mapsize changes"

This reverts commit 02285aca58.
This reverts commit 38e71c68de.
This reverts commit a5e4eecb1e.
This reverts commit d8e18551c3.
This reverts commit 5926e54bba.

libraries/liblmdb/lmdb.h

@@ -411,7 +411,7 @@ typedef enum MDB_cursor_op {
 #define MDB_CURSOR_FULL	(-30787)
 	/** Page has not enough space - internal error */
 #define MDB_PAGE_FULL	(-30786)
-	/** Environment mapsize was changed by another process */
+	/** Database contents grew beyond environment mapsize */
 #define MDB_MAP_RESIZED	(-30785)
 	/** MDB_INCOMPATIBLE: Operation and DB incompatible, or DB flags changed */
 #define MDB_INCOMPATIBLE	(-30784)
@@ -785,10 +785,7 @@ int  mdb_env_get_fd(MDB_env *env, mdb_filehandle_t *fd);
 	 * This function should be called after #mdb_env_create() and before #mdb_env_open().
 	 * It may be called at later times if no transactions are active in
 	 * this process. Note that the library does not check for this condition,
-	 * the caller must ensure it explicitly. The new size takes effect
+	 * the caller must ensure it explicitly.
-	 * immediately for the current process but will not be persisted to
-	 * any others until a write transaction has been committed by the
-	 * current process.
 	 *
 	 * If the mapsize is changed by another process, #mdb_txn_begin() will
 	 * return #MDB_MAP_RESIZED. This function may be called with a size

libraries/liblmdb/mdb.c

@@ -1074,8 +1074,6 @@ struct MDB_env {
 	HANDLE		me_mfd;			/**< just for writing the meta pages */
 	/** Failed to update the meta page. Probably an I/O error. */
 #define	MDB_FATAL_ERROR	0x80000000U
-	/** We're explicitly changing the mapsize. */
-#define	MDB_RESIZING	0x40000000U
 	/** Some fields are initialized. */
 #define	MDB_ENV_ACTIVE	0x20000000U
 	/** me_txkey is set */
@@ -2537,9 +2535,7 @@ mdb_txn_renew0(MDB_txn *txn)
 	}
 	txn->mt_dbflags[0] = txn->mt_dbflags[1] = DB_VALID;
 
-	/* If we didn't ask for a resize, but the size grew, fail */
+	if (env->me_maxpg < txn->mt_next_pgno) {
-	if (!(env->me_flags & MDB_RESIZING)
-		&& env->me_mapsize < meta->mm_mapsize) {
 		mdb_txn_reset0(txn, "renew0-mapfail");
 		if (new_notls) {
 			txn->mt_u.reader->mr_pid = 0;
@@ -3277,13 +3273,8 @@ mdb_txn_commit(MDB_txn *txn)
 	mdb_cursors_close(txn, 0);
 
 	if (!txn->mt_u.dirty_list[0].mid &&
-		!(txn->mt_flags & (MDB_TXN_DIRTY|MDB_TXN_SPILLS))) {
+		!(txn->mt_flags & (MDB_TXN_DIRTY|MDB_TXN_SPILLS)))
-		if ((env->me_flags & MDB_RESIZING)
-			&& (rc = mdb_env_write_meta(txn))) {
-			goto fail;
-		}
 		goto done;
-	}
 
 	DPRINTF(("committing txn %"Z"u %p on mdbenv %p, root page %"Z"u",
 	    txn->mt_txnid, (void*)txn, (void*)env, txn->mt_dbs[MAIN_DBI].md_root));
@@ -3324,6 +3315,7 @@ mdb_txn_commit(MDB_txn *txn)
 #endif
 
 	if ((rc = mdb_page_flush(txn, 0)) ||
+		(rc = mdb_env_sync(env, 0)) ||
 		(rc = mdb_env_write_meta(txn)))
 		goto fail;
 
@@ -3480,7 +3472,7 @@ mdb_env_init_meta(MDB_env *env, MDB_meta *meta)
 static int
 mdb_env_write_meta(MDB_txn *txn)
 {
-	MDB_env *env = txn->mt_env;
+	MDB_env *env;
 	MDB_meta	meta, metab, *mp;
 	off_t off;
 	int rc, len, toggle;
@@ -3492,22 +3484,17 @@ mdb_env_write_meta(MDB_txn *txn)
 	int r2;
 #endif
 
-	/* Sync data and previous metapage before writing a new metapage */
-	if ((rc = mdb_env_sync(env, 0)) != MDB_SUCCESS)
-		return rc;
-
 	toggle = txn->mt_txnid & 1;
 	DPRINTF(("writing meta page %d for root page %"Z"u",
 		toggle, txn->mt_dbs[MAIN_DBI].md_root));
 
+	env = txn->mt_env;
 	mp = env->me_metas[toggle];
 
 	if (env->me_flags & MDB_WRITEMAP) {
-		/* Persist any changes of mapsize config */
+		/* Persist any increases of mapsize config */
-		if (env->me_flags & MDB_RESIZING) {
+		if (env->me_mapsize > mp->mm_mapsize)
 			mp->mm_mapsize = env->me_mapsize;
-			env->me_flags ^= MDB_RESIZING;
-		}
 		mp->mm_dbs[0] = txn->mt_dbs[0];
 		mp->mm_dbs[1] = txn->mt_dbs[1];
 		mp->mm_last_pg = txn->mt_next_pgno - 1;
@@ -3535,11 +3522,10 @@ mdb_env_write_meta(MDB_txn *txn)
 	metab.mm_last_pg = env->me_metas[toggle]->mm_last_pg;
 
 	ptr = (char *)&meta;
-	if (env->me_flags & MDB_RESIZING) {
+	if (env->me_mapsize > mp->mm_mapsize) {
-		/* Persist any changes of mapsize config */
+		/* Persist any increases of mapsize config */
 		meta.mm_mapsize = env->me_mapsize;
 		off = offsetof(MDB_meta, mm_mapsize);
-		env->me_flags ^= MDB_RESIZING;
 	} else {
 		off = offsetof(MDB_meta, mm_dbs[0].md_depth);
 	}
@@ -3728,14 +3714,13 @@ mdb_env_set_mapsize(MDB_env *env, size_t size)
 	 * sure there are no active txns.
 	 */
 	if (env->me_map) {
-		int rc, change = 0;
+		int rc;
 		void *old;
 		if (env->me_txn)
 			return EINVAL;
 		if (!size)
 			size = env->me_metas[mdb_env_pick_meta(env)]->mm_mapsize;
-		else {
+		else if (size < env->me_mapsize) {
-			if (size < env->me_mapsize) {
 			/* If the configured size is smaller, make sure it's
 			 * still big enough. Silently round up to minimum if not.
 			 */
@@ -3743,19 +3728,12 @@ mdb_env_set_mapsize(MDB_env *env, size_t size)
 			if (size < minsize)
 				size = minsize;
 		}
-			/* nothing actually changed */
-			if (size == env->me_mapsize)
-				return MDB_SUCCESS;
-			change = 1;
-		}
 		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;
-		if (change)
-			env->me_flags |= MDB_RESIZING;
 	}
 	env->me_mapsize = size;
 	if (env->me_psize)
@@ -3828,8 +3806,7 @@ mdb_env_open2(MDB_env *env)
 		 * else use the size recorded in the existing env.
 		 */
 		env->me_mapsize = newenv ? DEFAULT_MAPSIZE : meta.mm_mapsize;
-	} else {
+	} else if (env->me_mapsize < meta.mm_mapsize) {
-		if (env->me_mapsize < meta.mm_mapsize) {
 		/* If the configured size is smaller, make sure it's
 		 * still big enough. Silently round up to minimum if not.
 		 */
@@ -3837,9 +3814,6 @@ mdb_env_open2(MDB_env *env)
 		if (env->me_mapsize < minsize)
 			env->me_mapsize = minsize;
 	}
-		if (env->me_mapsize != meta.mm_mapsize)
-			env->me_flags |= MDB_RESIZING;
-	}
 
 	rc = mdb_env_map(env, (flags & MDB_FIXEDMAP) ? meta.mm_address : NULL);
 	if (rc)