From 595f9e700d17d6269b5a8cf5ecc643cb927d88aa Mon Sep 17 00:00:00 2001
From: Leo Yuriev <leo@yuriev.ru>
Date: Wed, 5 Aug 2015 13:23:30 +0300
Subject: [PATCH] lmdb: fix b-tree walking bug in case empty db.

Change-Id: I28c0985493327babe4d2ae5c6cd56116a26e6034
---
 mdb.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/mdb.c b/mdb.c
index 66eabeac..a4b68a36 100644
--- a/mdb.c
+++ b/mdb.c
@@ -9727,6 +9727,10 @@ mdb_env_walk(mdb_walk_ctx_t *ctx, const char* dbi, pgno_t pg, int flags, int dee
 	int rc;
 	unsigned i;
 
+	/* Empty DB, nothing to do */
+	if (pg == P_INVALID)
+		return MDB_SUCCESS;
+
 	if (deep < 2) {
 		if ((rc = mdb_page_get(ctx->mw_txn, pg, &mp, NULL)) != 0)
 			return rc;
@@ -9736,10 +9740,6 @@ mdb_env_walk(mdb_walk_ctx_t *ctx, const char* dbi, pgno_t pg, int flags, int dee
 			return rc;
 	}
 
-	/* Empty DB, nothing to do */
-	if (pg == P_INVALID)
-		return MDB_SUCCESS;
-
 	mc.mc_snum = 1;
 	mc.mc_top = 0;
 	mc.mc_txn = ctx->mw_txn;