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Commit e2ac8363 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Darrick J. Wong
Browse files

xfs: simplify xfs_bmap_punch_delalloc_range 



Instead of using xfs_bmapi_read to find delalloc extents and then punch
them out using xfs_bunmapi, opencode the loop to iterate over the extents
and call xfs_bmap_del_extent_delay directly.  This both simplifies the
code and reduces the number of extent tree lookups required.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarBrian Foster <bfoster@redhat.com>
Reviewed-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
parent ce397d21

fs/xfs/xfs_bmap_util.c

+32 −53
Original line number Diff line number Diff line
@@ -685,12 +685,10 @@ xfs_getbmap( 
}



/*

 * dead simple method of punching delalyed allocation blocks from a range in

 * the inode. Walks a block at a time so will be slow, but is only executed in

 * rare error cases so the overhead is not critical. This will always punch out

 * both the start and end blocks, even if the ranges only partially overlap

 * them, so it is up to the caller to ensure that partial blocks are not

 * passed in.

 * Dead simple method of punching delalyed allocation blocks from a range in

 * the inode.  This will always punch out both the start and end blocks, even

 * if the ranges only partially overlap them, so it is up to the caller to

 * ensure that partial blocks are not passed in.

 */

int

xfs_bmap_punch_delalloc_range(
@@ -698,63 +696,44 @@ xfs_bmap_punch_delalloc_range( 
	xfs_fileoff_t		start_fsb,

	xfs_fileoff_t		length)

{

	xfs_fileoff_t		remaining = length;

	struct xfs_ifork	*ifp = &ip->i_df;

	xfs_fileoff_t		end_fsb = start_fsb + length;

	struct xfs_bmbt_irec	got, del;

	struct xfs_iext_cursor	icur;

	int			error = 0;



	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));



	do {

		int		done;

		xfs_bmbt_irec_t	imap;

		int		nimaps = 1;

		xfs_fsblock_t	firstblock;

		struct xfs_defer_ops dfops;

	if (!(ifp->if_flags & XFS_IFEXTENTS)) {

		error = xfs_iread_extents(NULL, ip, XFS_DATA_FORK);

		if (error)

			return error;

	}



		/*

		 * Map the range first and check that it is a delalloc extent

		 * before trying to unmap the range. Otherwise we will be

		 * trying to remove a real extent (which requires a

		 * transaction) or a hole, which is probably a bad idea...

		 */

		error = xfs_bmapi_read(ip, start_fsb, 1, &imap, &nimaps,

				       XFS_BMAPI_ENTIRE);

	if (!xfs_iext_lookup_extent_before(ip, ifp, &end_fsb, &icur, &got))

		return 0;



		if (error) {

			/* something screwed, just bail */

			if (!XFS_FORCED_SHUTDOWN(ip->i_mount)) {

				xfs_alert(ip->i_mount,

			"Failed delalloc mapping lookup ino %lld fsb %lld.",

						ip->i_ino, start_fsb);

			}

			break;

		}

		if (!nimaps) {

			/* nothing there */

			goto next_block;

		}

		if (imap.br_startblock != DELAYSTARTBLOCK) {

			/* been converted, ignore */

			goto next_block;

		}

		WARN_ON(imap.br_blockcount == 0);

	while (got.br_startoff + got.br_blockcount > start_fsb) {

		del = got;

		xfs_trim_extent(&del, start_fsb, length);



		/*

		 * Note: while we initialise the firstblock/dfops pair, they

		 * should never be used because blocks should never be

		 * allocated or freed for a delalloc extent and hence we need

		 * don't cancel or finish them after the xfs_bunmapi() call.

		 * A delete can push the cursor forward. Step back to the

		 * previous extent on non-delalloc or extents outside the

		 * target range.

		 */

		xfs_defer_init(&dfops, &firstblock);

		error = xfs_bunmapi(NULL, ip, start_fsb, 1, 0, 1, &firstblock,

					&dfops, &done);

		if (error)

		if (!del.br_blockcount ||

		    !isnullstartblock(del.br_startblock)) {

			if (!xfs_iext_prev_extent(ifp, &icur, &got))

				break;

			continue;

		}



		ASSERT(!xfs_defer_has_unfinished_work(&dfops));

next_block:

		start_fsb++;

		remaining--;

	} while(remaining > 0);

		error = xfs_bmap_del_extent_delay(ip, XFS_DATA_FORK, &icur,

						  &got, &del);

		if (error || !xfs_iext_get_extent(ifp, &icur, &got))

			break;

	}



	return error;

}