From 268940b80fa4096397fd0a28e6ad807e64120215 Mon Sep 17 00:00:00 2001 From: Hannes Reinecke Date: Wed, 30 Sep 2020 10:02:54 +0200 Subject: scsi: scsi_dh_alua: Return BLK_STS_AGAIN for ALUA transitioning state When the ALUA state indicates transitioning we should not retry the command immediately, but rather complete the command with BLK_STS_AGAIN to signal the completion handler that it might be retried. This allows multipathing to redirect the command to another path if possible, and avoid stalls during lengthy transitioning times. Link: https://lore.kernel.org/r/20200930080256.90964-3-hare@suse.de Reviewed-by: Ewan D. Milne Signed-off-by: Hannes Reinecke Signed-off-by: Martin K. Petersen --- drivers/scsi/device_handler/scsi_dh_alua.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/scsi/device_handler/scsi_dh_alua.c') diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c index f32da0ca529e..9e8d32d01d91 100644 --- a/drivers/scsi/device_handler/scsi_dh_alua.c +++ b/drivers/scsi/device_handler/scsi_dh_alua.c @@ -1091,7 +1091,7 @@ static blk_status_t alua_prep_fn(struct scsi_device *sdev, struct request *req) case SCSI_ACCESS_STATE_LBA: return BLK_STS_OK; case SCSI_ACCESS_STATE_TRANSITIONING: - return BLK_STS_RESOURCE; + return BLK_STS_AGAIN; default: req->rq_flags |= RQF_QUIET; return BLK_STS_IOERR; -- cgit v1.2.3 From fb908850ece3bc93a9d276f6dd8505d824b2789c Mon Sep 17 00:00:00 2001 From: Hannes Reinecke Date: Wed, 30 Sep 2020 10:02:55 +0200 Subject: scsi: scsi_dh_alua: Set 'transitioning' state on Unit Attention We should be setting the 'transitioning' ALUA state once we get a Unit Attention indicating the array is in transitioning. There are arrays which cannot respond to an RTPG while in transitioning, and others have issues correctly reporting the state. So better to set the state during Unit Attention handling and wait for TUR / RTPG to run its course. Link: https://lore.kernel.org/r/20200930080256.90964-4-hare@suse.de Reviewed-by: Ewan D. Milne Signed-off-by: Hannes Reinecke Signed-off-by: Martin K. Petersen --- drivers/scsi/device_handler/scsi_dh_alua.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'drivers/scsi/device_handler/scsi_dh_alua.c') diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c index 9e8d32d01d91..92b592e9ebcb 100644 --- a/drivers/scsi/device_handler/scsi_dh_alua.c +++ b/drivers/scsi/device_handler/scsi_dh_alua.c @@ -408,12 +408,20 @@ static char print_alua_state(unsigned char state) static int alua_check_sense(struct scsi_device *sdev, struct scsi_sense_hdr *sense_hdr) { + struct alua_dh_data *h = sdev->handler_data; + struct alua_port_group *pg; + switch (sense_hdr->sense_key) { case NOT_READY: if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0a) { /* * LUN Not Accessible - ALUA state transition */ + rcu_read_lock(); + pg = rcu_dereference(h->pg); + if (pg) + pg->state = SCSI_ACCESS_STATE_TRANSITIONING; + rcu_read_unlock(); alua_check(sdev, false); return NEEDS_RETRY; } -- cgit v1.2.3