xfs: add missing rmap error return

xfs_rmap_lookup_le_range can return errors, so we need to check for
them and bail out.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>

fs/xfs/libxfs/xfs_rmap.c

@@ -1374,6 +1374,8 @@ xfs_rmap_convert_shared(
 	 */
 	error = xfs_rmap_lookup_le_range(cur, bno, owner, offset, flags,
 			&PREV, &i);
+	if (error)
+		goto done;
 	XFS_WANT_CORRUPTED_GOTO(mp, i == 1, done);
 
 	ASSERT(PREV.rm_offset <= offset);