[PATCH 1/4] xfs: check unused nlink fields in the ondisk inode

Darrick J. Wong
2024-03-27T02:06:56Z

v2/v3 inodes use di_nlink and not di_onlink; and v1 inodes use di_onlink
and not di_nlink. Whichever field is not in use, make sure its contents
are zero, and teach xfs_scrub to fix that if it is.

This clears a bunch of missing scrub failure errors in xfs/385 for
core.onlink.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
fs/xfs/libxfs/xfs_inode_buf.c | 8 ++++++++
fs/xfs/scrub/inode_repair.c | 12 ++++++++++++
2 files changed, 20 insertions(+)

diff --git a/fs/xfs/libxfs/xfs_inode_buf.c b/fs/xfs/libxfs/xfs_inode_buf.c
index d0dcce462bf42..d79002343d0b6 100644
--- a/fs/xfs/libxfs/xfs_inode_buf.c
+++ b/fs/xfs/libxfs/xfs_inode_buf.c
@@ -491,6 +491,14 @@ xfs_dinode_verify(
return __this_address;
}

+ if (dip->di_version > 1) {
+ if (dip->di_onlink)
+ return __this_address;
+ } else {
+ if (dip->di_nlink)
+ return __this_address;
+ }
+
/* don't allow invalid i_size */
di_size = be64_to_cpu(dip->di_size);
if (di_size & (1ULL << 63))
diff --git a/fs/xfs/scrub/inode_repair.c b/fs/xfs/scrub/inode_repair.c
index 1851d17f0f2b7..228317b22bcb3 100644
--- a/fs/xfs/scrub/inode_repair.c
+++ b/fs/xfs/scrub/inode_repair.c
@@ -514,6 +514,17 @@ xrep_dinode_mode(
return 0;
}

+/* Fix unused link count fields having nonzero values. */
+STATIC void
+xrep_dinode_nlinks(
+ struct xfs_dinode *dip)
+{
+ if (dip->di_version > 1)
+ dip->di_onlink = 0;
+ else
+ dip->di_nlink = 0;
+}
+
/* Fix any conflicting flags that the verifiers complain about. */
STATIC void
xrep_dinode_flags(
@@ -1375,6 +1386,7 @@ xrep_dinode_core(
iget_error = xrep_dinode_mode(ri, dip);
if (iget_error)
goto write;
+ xrep_dinode_nlinks(dip);
xrep_dinode_flags(sc, dip, ri->rt_extents > 0);
xrep_dinode_size(ri, dip);
xrep_dinode_extsize_hints(sc, dip);