Commit 168eae80 authored by Darrick J. Wong's avatar Darrick J. Wong
Browse files

xfs: reflink can skip remap existing mappings 



If the source and destination map are identical, we can skip the remap
step to save some time.

Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: default avatarBrian Foster <bfoster@redhat.com>
parent 94b941fd

fs/xfs/xfs_reflink.c

+16 −0
Original line number Original line Diff line number Diff line
@@ -1035,6 +1035,22 @@ xfs_reflink_remap_extent( 




	trace_xfs_reflink_remap_extent_dest(ip, &smap);

	trace_xfs_reflink_remap_extent_dest(ip, &smap);





	/*

	 * Two extents mapped to the same physical block must not have

	 * different states; that's filesystem corruption.  Move on to the next

	 * extent if they're both holes or both the same physical extent.

	 */

	if (dmap->br_startblock == smap.br_startblock) {

		if (dmap->br_state != smap.br_state)

			error = -EFSCORRUPTED;

		goto out_cancel;

	}



	/* If both extents are unwritten, leave them alone. */

	if (dmap->br_state == XFS_EXT_UNWRITTEN &&

	    smap.br_state == XFS_EXT_UNWRITTEN)

		goto out_cancel;



	/* No reflinking if the AG of the dest mapping is low on space. */

	/* No reflinking if the AG of the dest mapping is low on space. */

	if (dmap_written) {

	if (dmap_written) {

		error = xfs_reflink_ag_has_free_space(mp,

		error = xfs_reflink_ag_has_free_space(mp,