diff mbox series

[5.9,162/252] xfs: directory scrub should check the null bestfree entries too

Message ID 20201123121843.409030494@linuxfoundation.org
State New
Headers show
Series None | expand

Commit Message

Greg KH Nov. 23, 2020, 12:21 p.m. UTC 
From: Darrick J. Wong <darrick.wong@oracle.com>

[ Upstream commit 6b48e5b8a20f653b7d64ccf99a498f2523bff752 ]

Teach the directory scrubber to check all the bestfree entries,
including the null ones.  We want to be able to detect the case where
the entry is null but there actually /is/ a directory data block.

Found by fuzzing lbests[0] = ones in xfs/391.

Fixes: df481968f33b ("xfs: scrub directory freespace")
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/xfs/scrub/dir.c | 21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)
diff mbox series

Patch

diff --git a/fs/xfs/scrub/dir.c b/fs/xfs/scrub/dir.c
index 7c432997edade..b045e95c2ea73 100644
--- a/fs/xfs/scrub/dir.c
+++ b/fs/xfs/scrub/dir.c
@@ -558,14 +558,27 @@  xchk_directory_leaf1_bestfree(
 	/* Check all the bestfree entries. */
 	for (i = 0; i < bestcount; i++, bestp++) {
 		best = be16_to_cpu(*bestp);
-		if (best == NULLDATAOFF)
-			continue;
 		error = xfs_dir3_data_read(sc->tp, sc->ip,
-				i * args->geo->fsbcount, 0, &dbp);
+				xfs_dir2_db_to_da(args->geo, i),
+				XFS_DABUF_MAP_HOLE_OK,
+				&dbp);
 		if (!xchk_fblock_process_error(sc, XFS_DATA_FORK, lblk,
 				&error))
 			break;
-		xchk_directory_check_freesp(sc, lblk, dbp, best);
+
+		if (!dbp) {
+			if (best != NULLDATAOFF) {
+				xchk_fblock_set_corrupt(sc, XFS_DATA_FORK,
+						lblk);
+				break;
+			}
+			continue;
+		}
+
+		if (best == NULLDATAOFF)
+			xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, lblk);
+		else
+			xchk_directory_check_freesp(sc, lblk, dbp, best);
 		xfs_trans_brelse(sc->tp, dbp);
 		if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
 			break;