diff --git a/[refs] b/[refs]
index 56c234b05d16..86ca9fefdd9a 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: aebf02430d25b6bd2b8542126fdcdb90e75a24b8
+refs/heads/master: 15b49132fc972c63894592f218ea5a9a61b1a18f
diff --git a/trunk/fs/ext4/balloc.c b/trunk/fs/ext4/balloc.c
index cf1821784a16..33938c120c85 100644
--- a/trunk/fs/ext4/balloc.c
+++ b/trunk/fs/ext4/balloc.c
@@ -358,7 +358,7 @@ void ext4_validate_block_bitmap(struct super_block *sb,
 }
 
 /**
- * ext4_read_block_bitmap()
+ * ext4_read_block_bitmap_nowait()
  * @sb:			super block
  * @block_group:	given block group
  *
@@ -457,6 +457,8 @@ ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group)
 	struct buffer_head *bh;
 
 	bh = ext4_read_block_bitmap_nowait(sb, block_group);
+	if (!bh)
+		return NULL;
 	if (ext4_wait_block_bitmap(sb, block_group, bh)) {
 		put_bh(bh);
 		return NULL;