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Add SCSI_PASSTHROUGH to zvols to enable UNMAP support
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When exporting ZVOLs as SCSI LUNs, by default Windows will not
issue them UNMAP commands. This reduces storage efficiency in
many cases.

We add the SCSI_PASSTHROUGH flag to the zvol's device queue,
which lets the SCSI target logic know that it can handle SCSI
commands.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: John Gallagher <john.gallagher@delphix.com>
Signed-off-by: Paul Dagnelie <pcd@delphix.com>
Closes openzfs#8933
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pcd1193182 authored and tonyhutter committed Aug 22, 2019
1 parent 92709c9 commit 6dc9872
Showing 1 changed file with 4 additions and 0 deletions.
4 changes: 4 additions & 0 deletions module/zfs/zvol.c
Original file line number Diff line number Diff line change
Expand Up @@ -1876,6 +1876,10 @@ zvol_create_minor_impl(const char *name)
#ifdef QUEUE_FLAG_ADD_RANDOM
blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, zv->zv_queue);
#endif
/* This flag was introduced in kernel version 4.12. */
#ifdef QUEUE_FLAG_SCSI_PASSTHROUGH
blk_queue_flag_set(QUEUE_FLAG_SCSI_PASSTHROUGH, zv->zv_queue);
#endif

if (spa_writeable(dmu_objset_spa(os))) {
if (zil_replay_disable)
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