[PATCH v2] ext2: add missing brelse in ext2_new_blocks()

[Chengguang Xu <cgxu519@mykernel.net>]

There is a missing brelse of bitmap_bh in the
case of retry.

Signed-off-by: Chengguang Xu <cgxu519@mykernel.net>
---
v1->v2:
- Add comment to explain why the fix is needed.

 fs/ext2/balloc.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/fs/ext2/balloc.c b/fs/ext2/balloc.c
index 924c1c765306..18e75adcd2f6 100644
--- a/fs/ext2/balloc.c
+++ b/fs/ext2/balloc.c
@@ -1313,6 +1313,13 @@ ext2_fsblk_t ext2_new_blocks(struct inode *inode, ext2_fsblk_t goal,
 	if (free_blocks > 0) {
 		grp_target_blk = ((goal - le32_to_cpu(es->s_first_data_block)) %
 				EXT2_BLOCKS_PER_GROUP(sb));
+		/*
+		 * In a special case that allocated blocks are in system zone,
+		 * we will retry block allocation due to failing to pass sanity
+		 * check. In this case, the bitmap_bh is non-null pointer and we
+		 * have to release it before calling read_block_bitmap().
+		 */
+		brelse(bitmap_bh);
 		bitmap_bh = read_block_bitmap(sb, group_no);
 		if (!bitmap_bh)
 			goto io_error;
-- 
2.20.1