xfs: cross-reference reverse-mapping btree

When scrubbing various btrees, we should cross-reference the records
with the reverse mapping btree and ensure that traversing the btree
finds the same number of blocks that the rmapbt thinks are owned by
that btree.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

fs/xfs/scrub/alloc.c

@@ -105,6 +105,7 @@ xfs_scrub_allocbt_xref(
 
 	xfs_scrub_allocbt_xref_other(sc, agbno, len);
 	xfs_scrub_xref_is_not_inode_chunk(sc, agbno, len);
+	xfs_scrub_xref_has_no_owner(sc, agbno, len);
 }
 
 /* Scrub a bnobt/cntbt record. */