[PATCH CANDIDATE v6.1 4/5] xfs: use the directory name hash function for dir scrubbing

["Theodore Ts'o" <tytso@mit.edu>]

From: "Darrick J. Wong" <djwong@kernel.org>

The directory code has a directory-specific hash computation function
that includes a modified hash function for case-insensitive lookups.
Hence we must use that function (and not the raw da_hashname) when
checking the dabtree structure.

Found by accidentally breaking xfs/188 to create an abnormally huge
case-insensitive directory and watching scrub break.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
(cherry picked from commit 9dceccc5822f2ecea12a89f24d7cad1f3e5eab7c)
---
 fs/xfs/scrub/dir.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/fs/xfs/scrub/dir.c b/fs/xfs/scrub/dir.c
index 5c87800ab223..ee29084ec44e 100644
--- a/fs/xfs/scrub/dir.c
+++ b/fs/xfs/scrub/dir.c
@@ -201,6 +201,7 @@ xchk_dir_rec(
 	struct xchk_da_btree		*ds,
 	int				level)
 {
+	struct xfs_name			dname = { };
 	struct xfs_da_state_blk		*blk = &ds->state->path.blk[level];
 	struct xfs_mount		*mp = ds->state->mp;
 	struct xfs_inode		*dp = ds->dargs.dp;
@@ -297,7 +298,11 @@ xchk_dir_rec(
 		xchk_fblock_set_corrupt(ds->sc, XFS_DATA_FORK, rec_bno);
 		goto out_relse;
 	}
-	calc_hash = xfs_da_hashname(dent->name, dent->namelen);
+
+	/* Does the directory hash match? */
+	dname.name = dent->name;
+	dname.len = dent->namelen;
+	calc_hash = xfs_dir2_hashname(mp, &dname);
 	if (calc_hash != hash)
 		xchk_fblock_set_corrupt(ds->sc, XFS_DATA_FORK, rec_bno);
 
-- 
2.31.0