On 01/12/2012 06:03 PM, Rob Evers wrote:
On 01/12/2012 04:43 AM, Hannes Reinecke wrote:
On 01/03/2012 08:20 PM, Rob Evers wrote:
From: Rob Evers<revers@xxxxxxxxxx>
When alua targets are transitioning, the scsi midlayer retry mechanism
continuously retries the scsi commands that are returning with not ready
transitioning status. The target is not capable of handling the
commands for time on the order of several seconds during these
transistions.
This patch delays the device queue for 2 seconds, which is in the same
order of aas transition time.
Also, handle all other cases where ADD_TO_MLQUEUE_DELAY could be
returned
instead of ADD_TO_MLQUEUE as if ADD_TO_MLQUEUE were being returned.
Problem found by array partner testing
change MLQUEUE_DEV_DLY_RTY to MLQUEUE_DELAYED_RETRY
I have been working on a different solution, whic
Signed-off-by: Rob Evers<revers@xxxxxxxxxx>
---
drivers/scsi/device_handler/scsi_dh_alua.c | 7 ++++---
drivers/scsi/scsi.c | 3 +++
drivers/scsi/scsi_error.c | 1 +
drivers/scsi/scsi_lib.c | 9 ++++++++-
include/scsi/scsi.h | 12 +++++++-----
5 files changed, 23 insertions(+), 9 deletions(-)
diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c
b/drivers/scsi/device_handler/scsi_dh_alua.c
index 4ef0212..33b8df7 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -233,7 +233,7 @@ static void stpg_endio(struct request *req, int
error)
goto done;
}
err = alua_check_sense(h->sdev,&sense_hdr);
- if (err == ADD_TO_MLQUEUE) {
+ if (err == ADD_TO_MLQUEUE || err == ADD_TO_MLQUEUE_DELAY) {
err = SCSI_DH_RETRY;
goto done;
}
@@ -443,7 +443,7 @@ static int alua_check_sense(struct scsi_device
*sdev,
/*
* LUN Not Accessible - ALUA state transition
*/
- return ADD_TO_MLQUEUE;
+ return ADD_TO_MLQUEUE_DELAY;
if (sense_hdr->asc == 0x04&& sense_hdr->ascq == 0x0b)
/*
* LUN Not Accessible -- Target port in standby state
@@ -521,7 +521,8 @@ static int alua_rtpg(struct scsi_device *sdev,
struct alua_dh_data *h)
return SCSI_DH_IO;
err = alua_check_sense(sdev,&sense_hdr);
- if (err == ADD_TO_MLQUEUE&& time_before(jiffies, expiry))
+ if ((err == ADD_TO_MLQUEUE || err == ADD_TO_MLQUEUE_DELAY)&&
+ time_before(jiffies, expiry))
goto retry;
sdev_printk(KERN_INFO, sdev,
"%s: rtpg sense code %02x/%02x/%02x\n",
Actually, this doesn't help if the RTPG command returns with the
mentioned error; then you'll just continue flooding the array with
RTPG commands. You'll need to delay the RTPG commands, too.
I thought that the rtpg command would get requeued into the
device queue that is being delayed anyway.
Isn't that true?
Nope.
rtpg is being send via the SG_IO path, for which the error is returned
directly without being retried.
So we'll need to fix it up in the alua handler.
Cheers,
Hannes
--
Dr. Hannes Reinecke zSeries & Storage
hare@xxxxxxx +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Markus Rex, HRB 16746 (AG Nürnberg)
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