[PATCH hci-8.1 0/5] scsi-disk: fix UNMAP and WRITE SAME racing with inactivation #VSTOR-151532

["Denis V. Lunev" <den@openvz.org>]

scsi-disk splits UNMAP into one discard per descriptor and a non-zero
WRITE SAME into 512 KiB writes, submitting each step from the
completion callback of the previous one. A drain in between only waits
for the step in flight; the next one is queued by
blk_wait_while_drained() and resumed by drain_end. When the drain is
the one in bdrv_inactivate_all() (end of live migration,
blockdev-set-active), the resumed request hits an inactive node:

  bdrv_co_write_req_prepare: Assertion
  `!(bs->open_flags & BDRV_O_INACTIVE)' failed.

We hit this in production on a guest UNMAP with 38 descriptors.

The fix follows the one Kevin did for IDE TRIM:
https://lore.kernel.org/qemu-devel/20260421161132.99878-1-kwolf@redhat.com/

Signed-off-by: Denis V. Lunev <den@openvz.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Hanna Reitz <hreitz@redhat.com>
Cc: Fabiano Rosas <farosas@suse.de>
Cc: Laurent Vivier <lvivier@redhat.com>
Cc: qemu-stable@nongnu.org

Denis V. Lunev (5):
  scsi-disk: check all UNMAP descriptors before discarding any
    #VSTOR-151532
  scsi-disk: fix UNMAP racing with inactivation of block nodes
    #VSTOR-151532
  scsi-disk: fix WRITE SAME racing with inactivation of block nodes
    #VSTOR-151532
  virtio-scsi-test: split virtio_scsi_do_command() into submit and wait
    #VSTOR-151532
  virtio-scsi-test: test UNMAP and WRITE SAME during inactivation
    #VSTOR-151532

 hw/scsi/scsi-disk.c            | 278 +++++++++++++++++++--------------
 tests/qtest/virtio-scsi-test.c | 173 +++++++++++++++++---
 2 files changed, 309 insertions(+), 142 deletions(-)

base-commit: 81aea91c7f71cba39b4c3340579d45f0256a91d8

-- 
2.53.0