xfs: convert a few more directory asserts to corruption

Yet another round of playing whack-a-mole with directory code that
asserts on corrupt on-disk metadata when it really should be returning
-EFSCORRUPTED instead of ASSERTing.  Found by a xfs/391 crash while
lastbit fuzzing of ltail.bestcount.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>

fs/xfs/libxfs/xfs_dir2_leaf.c

@@ -1415,7 +1415,8 @@ xfs_dir2_leaf_removename(
 	oldbest = be16_to_cpu(bf[0].length);
 	ltp = xfs_dir2_leaf_tail_p(args->geo, leaf);
 	bestsp = xfs_dir2_leaf_bests_p(ltp);
-	ASSERT(be16_to_cpu(bestsp[db]) == oldbest);
+	if (be16_to_cpu(bestsp[db]) != oldbest)
+		return -EFSCORRUPTED;
 	/*
 	 * Mark the former data entry unused.
 	 */

fs/xfs/libxfs/xfs_dir2_node.c

@@ -387,8 +387,9 @@ xfs_dir2_leaf_to_node(
 	dp->d_ops->free_hdr_from_disk(&freehdr, free);
 	leaf = lbp->b_addr;
 	ltp = xfs_dir2_leaf_tail_p(args->geo, leaf);
-	ASSERT(be32_to_cpu(ltp->bestcount) <=
-				(uint)dp->i_d.di_size / args->geo->blksize);
+	if (be32_to_cpu(ltp->bestcount) >
+				(uint)dp->i_d.di_size / args->geo->blksize)
+		return -EFSCORRUPTED;
 
 	/*
 	 * Copy freespace entries from the leaf block to the new block.