Commit 3e0ee78f authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Dave Chinner
Browse files

xfs: optimize xfs_reflink_cancel_cow_blocks 



Rewrite xfs_reflink_cancel_cow_blocks so that we only do a search for
the first extent in the extent list and then iterate over the remaining
extents using the extent index, passing the extent we operate on
directly to xfs_bmap_del_extent_delay or xfs_bmap_del_extent_cow instead
of going through xfs_bunmapi and doing yet another extent list lookup.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: default avatarBrian Foster <bfoster@redhat.com>
Signed-off-by: default avatarDave Chinner <david@fromorbit.com>
parent fa5c836c

fs/xfs/xfs_reflink.c

+23 −28
Original line number Diff line number Diff line
@@ -511,53 +511,49 @@ xfs_reflink_cancel_cow_blocks( 
	xfs_fileoff_t			offset_fsb,

	xfs_fileoff_t			end_fsb)

{

	struct xfs_bmbt_irec		irec;

	xfs_filblks_t			count_fsb;

	struct xfs_ifork		*ifp = XFS_IFORK_PTR(ip, XFS_COW_FORK);

	struct xfs_bmbt_irec		got, prev, del;

	xfs_extnum_t			idx;

	xfs_fsblock_t			firstfsb;

	struct xfs_defer_ops		dfops;

	int				error = 0;

	int				nimaps;

	int				error = 0, eof = 0;



	if (!xfs_is_reflink_inode(ip))

		return 0;



	/* Go find the old extent in the CoW fork. */

	while (offset_fsb < end_fsb) {

		nimaps = 1;

		count_fsb = (xfs_filblks_t)(end_fsb - offset_fsb);

		error = xfs_bmapi_read(ip, offset_fsb, count_fsb, &irec,

				&nimaps, XFS_BMAPI_COWFORK);

		if (error)

			break;

		ASSERT(nimaps == 1);

	xfs_bmap_search_extents(ip, offset_fsb, XFS_COW_FORK, &eof, &idx,

			&got, &prev);

	if (eof)

		return 0;



		trace_xfs_reflink_cancel_cow(ip, &irec);

	while (got.br_startoff < end_fsb) {

		del = got;

		xfs_trim_extent(&del, offset_fsb, end_fsb - offset_fsb);

		trace_xfs_reflink_cancel_cow(ip, &del);



		if (irec.br_startblock == DELAYSTARTBLOCK) {

			/* Remove the mapping from the CoW fork. */

			error = xfs_bunmapi_cow(ip, &irec);

		if (isnullstartblock(del.br_startblock)) {

			error = xfs_bmap_del_extent_delay(ip, XFS_COW_FORK,

					&idx, &got, &del);

			if (error)

				break;

		} else if (irec.br_startblock == HOLESTARTBLOCK) {

			/* empty */

		} else {

			xfs_trans_ijoin(*tpp, ip, 0);

			xfs_defer_init(&dfops, &firstfsb);



			/* Free the CoW orphan record. */

			error = xfs_refcount_free_cow_extent(ip->i_mount,

					&dfops, irec.br_startblock,

					irec.br_blockcount);

					&dfops, del.br_startblock,

					del.br_blockcount);

			if (error)

				break;



			xfs_bmap_add_free(ip->i_mount, &dfops,

					irec.br_startblock, irec.br_blockcount,

					del.br_startblock, del.br_blockcount,

					NULL);



			/* Update quota accounting */

			xfs_trans_mod_dquot_byino(*tpp, ip, XFS_TRANS_DQ_BCOUNT,

					-(long)irec.br_blockcount);

					-(long)del.br_blockcount);



			/* Roll the transaction */

			error = xfs_defer_finish(tpp, &dfops, ip);
@@ -567,13 +563,12 @@ xfs_reflink_cancel_cow_blocks( 
			}



			/* Remove the mapping from the CoW fork. */

			error = xfs_bunmapi_cow(ip, &irec);

			if (error)

				break;

			xfs_bmap_del_extent_cow(ip, &idx, &got, &del);

		}



		/* Roll on... */

		offset_fsb = irec.br_startoff + irec.br_blockcount;

		if (++idx >= ifp->if_bytes / sizeof(struct xfs_bmbt_rec))

			return 0;

		xfs_bmbt_get_all(xfs_iext_get_ext(ifp, idx), &got);

	}



	return error;

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