[PATCH v2 0/5] btrfs: zoned: fixes for zone finishing

[Naohiro Aota <naohiro.aota@wdc.com>]

- Changes
 - v2
   - Rename some functions/variables.
   - Intoduce btrfs_zoned_bg_is_full() to check if a block group is fully
     allocated or not.
   - Add some more comments.

* Note: this series depends on "btrfs: zoned: fix zone activation logic"
  series (patch 1). I found the bug addressed in the series while I'm
  introducing the helper. 

Commit be1a1d7a5d24 ("btrfs: zoned: finish fully written block group")
introduced zone finishing a block group when the IO reaches at the end of
the block group. However, since the zone capacity may not aligned to 16KB
(node size), we can leave an un-allocatable space at the end of a block
group. Also, it turned out that metadata zone finishing never works
actually.

This series addresses these issues by rewriting metadata zone finishing
code to use a workqueue to process the finishing work.

Patch 1 introduces a helper to check if a block group is fully allocated.
The helper is used in patch 2.

Patch 2 is a clean-up patch to consolidate zone finishing function for
better maintainability.

Patch 3 changes the left region calculation so that it finishes a block
group when there is no more space left for allocation.

Patch 4 fixes metadata block group finishing which is not actually working.

Patch 5 implements zone finishing of an unused block group and fixes active
block group accounting. This patch is a bit unrelated to other ones. But,
the patch is tested with the previous patches applied, so let me go with
the same series.

Naohiro Aota (5):
  btrfs: zoned: introduce btrfs_zoned_bg_is_full
  btrfs: zoned: consolidate zone finish function
  btrfs: zoned: finish BG when there are no more allocatable bytes left
  btrfs: zoned: properly finish block group on metadata write
  btrfs: zoned: zone finish unused block group

 fs/btrfs/block-group.c |   8 ++
 fs/btrfs/block-group.h |   2 +
 fs/btrfs/extent-tree.c |   3 +-
 fs/btrfs/extent_io.c   |   6 +-
 fs/btrfs/extent_io.h   |   1 -
 fs/btrfs/zoned.c       | 176 ++++++++++++++++++++++++-----------------
 fs/btrfs/zoned.h       |  11 +++
 7 files changed, 128 insertions(+), 79 deletions(-)

-- 
2.35.1