Commit d004d70d authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Carlos Maiolino
Browse files

xfs: remove xfs_last_used_zone 



This was my first attempt at caching the last used zone.  But it turns out
for O_DIRECT or RWF_DONTCACHE that operate concurrently or in very short
sequence, the bmap btree does not record a written extent yet, so it fails.
Because it then still finds the last written zone it can lead to a weird
ping-pong around a few zones with writers seeing different values.

Remove it entirely as the later added xfs_cached_zone actually does a
much better job enforcing the locality as the zone is associated with the
inode in the MRU cache as soon as the zone is selected.

Fixes: 4e4d5207 ("xfs: add the zoned space allocator")
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Tested-by: default avatarDamien Le Moal <dlemoal@kernel.org>
Reviewed-by: default avatarHans Holmberg <hans.holmberg@wdc.com>
Signed-off-by: default avatarCarlos Maiolino <cem@kernel.org>
parent 9ce43caa

fs/xfs/xfs_zone_alloc.c

+2 −43
Original line number Diff line number Diff line
@@ -374,44 +374,6 @@ xfs_zone_free_blocks( 
	return 0;

}



/*

 * Check if the zone containing the data just before the offset we are

 * writing to is still open and has space.

 */

static struct xfs_open_zone *

xfs_last_used_zone(

	struct iomap_ioend	*ioend)

{

	struct xfs_inode	*ip = XFS_I(ioend->io_inode);

	struct xfs_mount	*mp = ip->i_mount;

	xfs_fileoff_t		offset_fsb = XFS_B_TO_FSB(mp, ioend->io_offset);

	struct xfs_rtgroup	*rtg = NULL;

	struct xfs_open_zone	*oz = NULL;

	struct xfs_iext_cursor	icur;

	struct xfs_bmbt_irec	got;



	xfs_ilock(ip, XFS_ILOCK_SHARED);

	if (!xfs_iext_lookup_extent_before(ip, &ip->i_df, &offset_fsb,

				&icur, &got)) {

		xfs_iunlock(ip, XFS_ILOCK_SHARED);

		return NULL;

	}

	xfs_iunlock(ip, XFS_ILOCK_SHARED);



	rtg = xfs_rtgroup_grab(mp, xfs_rtb_to_rgno(mp, got.br_startblock));

	if (!rtg)

		return NULL;



	xfs_ilock(rtg_rmap(rtg), XFS_ILOCK_SHARED);

	oz = READ_ONCE(rtg->rtg_open_zone);

	if (oz && (oz->oz_is_gc || !atomic_inc_not_zero(&oz->oz_ref)))

		oz = NULL;

	xfs_iunlock(rtg_rmap(rtg), XFS_ILOCK_SHARED);



	xfs_rtgroup_rele(rtg);

	return oz;

}



static struct xfs_group *

xfs_find_free_zone(

	struct xfs_mount	*mp,
@@ -918,12 +880,9 @@ xfs_zone_alloc_and_submit( 
		goto out_error;



	/*

	 * If we don't have a cached zone in this write context, see if the

	 * last extent before the one we are writing to points to an active

	 * zone.  If so, just continue writing to it.

	 * If we don't have a locally cached zone in this write context, see if

	 * the inode is still associated with a zone and use that if so.

	 */

	if (!*oz && ioend->io_offset)

		*oz = xfs_last_used_zone(ioend);

	if (!*oz)

		*oz = xfs_cached_zone(mp, ip);