[PATCH 6.6 08/21] xfs: introduce protection for drop nlink

From: Catherine Hoang <catherine.hoang@oracle.com>
To: stable@vger.kernel.org
Cc: linux-xfs@vger.kernel.org
Subject: [PATCH 6.6 08/21] xfs: introduce protection for drop nlink
Date: Thu,  8 Feb 2024 15:20:41 -0800	[thread overview]
Message-ID: <20240208232054.15778-9-catherine.hoang@oracle.com> (raw)
In-Reply-To: <20240208232054.15778-1-catherine.hoang@oracle.com>

From: Cheng Lin <cheng.lin130@zte.com.cn>

commit 2b99e410b28f5a75ae417e6389e767c7745d6fce upstream.

When abnormal drop_nlink are detected on the inode,
return error, to avoid corruption propagation.

Signed-off-by: Cheng Lin <cheng.lin130@zte.com.cn>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
Signed-off-by: Catherine Hoang <catherine.hoang@oracle.com>
Acked-by: Chandan Babu R <chandanbabu@kernel.org>
---
 fs/xfs/xfs_inode.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 4d55f58d99b7..fb85c5c81745 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -918,6 +918,13 @@ xfs_droplink(
 	xfs_trans_t *tp,
 	xfs_inode_t *ip)
 {
+	if (VFS_I(ip)->i_nlink == 0) {
+		xfs_alert(ip->i_mount,
+			  "%s: Attempt to drop inode (%llu) with nlink zero.",
+			  __func__, ip->i_ino);
+		return -EFSCORRUPTED;
+	}
+
 	xfs_trans_ichgtime(tp, ip, XFS_ICHGTIME_CHG);
 
 	drop_nlink(VFS_I(ip));
-- 
2.39.3

