[PATCH v6] xfs: introduce protection for drop nlink

cheng.lin130
2023-10-10T02:09:32Z

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

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>
---
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 9e62cc500..0fa1ac5e0 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -919,6 +919,13 @@ 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));
--
2.18.1