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(-) -- 2.44.0