From: Darrick J. Wong <djwong@kernel.org>
Date: Mon, 15 Apr 2024 21:55:03 +0000 (-0700)
Subject: xfs: check unused nlink fields in the ondisk inode
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=40cb8613d6122ca80a9e42e4cecc4d308c3b80fb;p=linux.git

xfs: check unused nlink fields in the ondisk inode

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>
---

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 0dde5df2f8d39..e3b74ea50fdef 100644
--- a/fs/xfs/scrub/inode_repair.c
+++ b/fs/xfs/scrub/inode_repair.c
@@ -516,6 +516,17 @@ 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(
@@ -1377,6 +1388,7 @@ 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);