[PATCH] xfs: dabtree scrub needs to range-check level

["Darrick J. Wong" <darrick.wong@oracle.com>]

From: Darrick J. Wong <darrick.wong@oracle.com>

Make sure scrub's dabtree iterator function checks that we're not
going deeper in the stack than our cursor permits.  Found by sparse.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 fs/xfs/scrub/dabtree.c |    5 +++++
 1 file changed, 5 insertions(+)

diff --git a/fs/xfs/scrub/dabtree.c b/fs/xfs/scrub/dabtree.c
index c6ab123b6051..5c6175d074e0 100644
--- a/fs/xfs/scrub/dabtree.c
+++ b/fs/xfs/scrub/dabtree.c
@@ -604,6 +604,11 @@ xchk_da_btree(
 		/* Drill another level deeper. */
 		blkno = be32_to_cpu(key->before);
 		level++;
+		if (level >= XFS_DA_NODE_MAXDEPTH) {
+			/* Too deep! */
+			xchk_da_set_corrupt(&ds, level - 1);
+			break;
+		}
 		ds.tree_level--;
 		error = xchk_da_btree_block(&ds, level, blkno);
 		if (error)