[v2,00/14] Zone write plugging fixes and cleanup

Message

Damien Le Moal May 1, 2024, 12:09 a.m. UTC

Jens, Mike,

With more testing of zone write plugging on more device setups,
including weird/test setups (with scsi debug and null_blk), several
issues were identified. This patch series addresses them and cleanup the
code a little to try to make it more obvious.

The first patch is a DM modification to not expose zoned devices
composed solely of conventional zones as zoned block devices. The second
patch is a fix partly related to this to expose a correct max open zones
limit for devices with no limits (which DM devices are as the max
open/active limit is not propagated to the mapped device as there is no
easy way to do that).

Patches 3 to 9 are bug fixes. The most serious problem among theses was
detected with tests using scsi_debug zoned devices and is fixed in
patch 7.

Patches 10 to 14 improve and cleanup the code.

Changes from v1:
 - Changed patch 4 as suggested by Christoph
 - Added additional comments in patch 7 to clarify the check for the
   zone write plug reference count in disk_should_remove_zone_wplug()
 - Added patch 14
 - Added review tags

Damien Le Moal (14):
  dm: Check that a zoned table leads to a valid mapped device
  block: Exclude conventional zones when faking max open limit
  block: Fix zone write plug initialization from blk_revalidate_zone_cb()
  block: Fix reference counting for zone write plugs in error state
  block: Hold a reference on zone write plugs to schedule submission
  block: Unhash a zone write plug only if needed
  block: Do not remove zone write plugs still in use
  block: Fix flush request sector restore
  block: Fix handling of non-empty flush write requests to zones
  block: Improve blk_zone_write_plug_bio_merged()
  block: Improve zone write request completion handling
  block: Simplify blk_zone_write_plug_bio_endio()
  block: Simplify zone write plug BIO abort
  block: Cleanup blk_revalidate_zone_cb()

 block/blk-flush.c     |   3 +-
 block/blk-mq.c        |  12 +-
 block/blk-zoned.c     | 407 +++++++++++++++++++++++++++---------------
 block/blk.h           |  12 +-
 drivers/md/dm-table.c |   3 +-
 drivers/md/dm-zone.c  |  53 ++++++
 6 files changed, 334 insertions(+), 156 deletions(-)