[PATCH 0/4] scsi: remove devices in ALUA transitioning status

Hannes Reinecke
2020-09-30T08:03:03Z

Hi all,

during testing we found that there is an issue with dev_loss_tmo and
devices in ALUA transitioning state.
What happens is that I/O gets requeued via BLK_STS_RESOURCE for these
devices, so when dev_loss_tmo triggers the SCSI core cannot flush the
request list as I/O is simply requeued.

So when the driver is trying to re-establish the device it'll wait for
that last reference to drop in order to re-attach the device, but as I/O
is still outstanding on the (old) device it'll wait for ever.

Fix this by returning 'BLK_STS_AGAIN' from scsi_dh_alua when the device
is in ALUA transitioning, and also set the 'transitioning' state when
scsi_dh_alua is receiving a sense code, and not only after scsi_dh_alua
successfully received the response to a REPORT TARGET PORT GROUPS
command.

Hannes Reinecke (4):
block: return status code in blk_mq_end_request()
scsi_dh_alua: return BLK_STS_AGAIN for ALUA transitioning state
scsi_dh_alua: set 'transitioning' state on unit attention
scsi: return BLK_STS_AGAIN for ALUA transitioning

block/blk-mq.c | 2 +-
drivers/scsi/device_handler/scsi_dh_alua.c | 10 +++++++++-
drivers/scsi/scsi_lib.c | 8 ++++++++
3 files changed, 18 insertions(+), 2 deletions(-)

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2.16.4