linux-kernel - [PATCH v2 2/7] ext4: avoid potential buffer_head leak in __ext4_new

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Message-Id: <20240820132234.2759926-3-shikemeng@huaweicloud.com>
Date: Tue, 20 Aug 2024 21:22:29 +0800
From: Kemeng Shi <shikemeng@...weicloud.com>
To: tytso@....edu,
	adilger.kernel@...ger.ca
Cc: harshadshirwadkar@...il.com,
	darrick.wong@...cle.com,
	akpm@...l.org,
	shaggy@...tin.ibm.com,
	linux-ext4@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH v2 2/7] ext4: avoid potential buffer_head leak in __ext4_new_inode()

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.

Fixes: 9008a58e5dce ("ext4: make the bitmap read routines return real error codes")
Signed-off-by: Kemeng Shi <shikemeng@...weicloud.com>
---
 fs/ext4/ialloc.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index ad7f13976dc6..9e2c08a8665f 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -1054,12 +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))
+			goto next_group;
 
 repeat_in_this_group:
 		ret2 = find_inode_bit(sb, group, inode_bitmap_bh, &ino);
-- 
2.30.0