[PATCH 2/7] ext4: avoid potential buffer_head leak in __ext4_new_inode

[Kemeng Shi]

If a group is marked EXT4_GROUP_INFO_IBITMAP_CORRUPT after it's inode
bitmap buffer_head was successfully verified, then __ext4_new_inode
will get a valid inode_bitmap_bh of a corrupted group from
ext4_read_inode_bitmap in which case inode_bitmap_bh misses a release.
Hnadle "IS_ERR(inode_bitmap_bh)" and group corruption separately like
how ext4_free_inode does to avoid buffer_head leak.

Signed-off-by: Kemeng Shi <shikemeng@xxxxxxxxxxxxxxx>
---
 fs/ext4/ialloc.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index ad7f13976dc6..f24a238b6b09 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -1054,9 +1054,13 @@ struct inode *__ext4_new_inode(struct mnt_idmap *idmap,
 		brelse(inode_bitmap_bh);
 		inode_bitmap_bh = ext4_read_inode_bitmap(sb, group);
 		/* Skip groups with suspicious inode tables */
-		if (((!(sbi->s_mount_state & EXT4_FC_REPLAY))
-		     && EXT4_MB_GRP_IBITMAP_CORRUPT(grp)) ||
-		    IS_ERR(inode_bitmap_bh)) {
+		if (IS_ERR(inode_bitmap_bh)) {
+			inode_bitmap_bh = NULL;
+			goto next_group;
+		}
+		if (!(sbi->s_mount_state & EXT4_FC_REPLAY) &&
+		    EXT4_MB_GRP_IBITMAP_CORRUPT(grp)) {
+			brelse(inode_bitmap_bh);
 			inode_bitmap_bh = NULL;
 			goto next_group;
 		}
-- 
2.30.0