[PATCH v3 00/14] Zone write plugging fixes and cleanup

Damien Le Moal
2024-05-01T11:09:09Z

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 v2:
- Fixed comment in patch 1
- Addressed Christoph's suggestion in patch 2 (mempool_resize call).
- Added review tags

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 | 403 +++++++++++++++++++++++++++---------------
block/blk.h | 12 +-
drivers/md/dm-table.c | 3 +-
drivers/md/dm-zone.c | 57 ++++++
6 files changed, 335 insertions(+), 155 deletions(-)

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2.44.0