From f3d3f60e3dd051f2a4fcb0fe4deb000e988f3eab Mon Sep 17 00:00:00 2001
From: Hallvard Furuseth <hallvard@openldap.org>
Date: Mon, 8 Dec 2014 09:56:36 +0100
Subject: [PATCH] Try to avoid an invalid datafile after failed init

---
 libraries/liblmdb/mdb.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/libraries/liblmdb/mdb.c b/libraries/liblmdb/mdb.c
index d5387bc..da09f8d 100644
--- a/libraries/liblmdb/mdb.c
+++ b/libraries/liblmdb/mdb.c
@@ -4008,6 +4008,20 @@ mdb_env_open2(MDB_env *env)
 	}
 	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;
+	}
+
 	rc = mdb_env_map(env, (flags & MDB_FIXEDMAP) ? meta.mm_address : NULL);
 	if (rc)
 		return rc;