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: 4e4d52075577 ("xfs: add the zoned space allocator")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Hans Holmberg <hans.holmberg@wdc.com>
Signed-off-by: Carlos Maiolino <cem@kernel.org>

diff --git a/fs/xfs/xfs_zone_alloc.c b/fs/xfs/xfs_zone_alloc.c
index f8bd6d7417554131c8de90af81c22c0baf94e3c0..f28214c28ab5455670f7ef2a57e8317c73b5f204 100644 (file)
--- a/fs/xfs/xfs_zone_alloc.c
+++ b/fs/xfs/xfs_zone_alloc.c
@@ -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);