Re: [PATCH] I/O errors for ALUA state transitions

[Hannes Reinecke <hare@suse.de>]

On 9/7/21 5:59 PM, michael.christie@oracle.com wrote:
> On 9/7/21 2:16 AM, Hannes Reinecke wrote:
>> From: Rajashekhar M A <rajs@netapp.com>
>>
>> When a host is configured with a few LUNs and IO is running,
>> injecting FC faults repeatedly leads to path recovery problems.
>> The LUNs have 4 paths each and 3 of them come back active after
>> say an FC fault which makes two of the paths go down, instead of
>> all 4. This happens after several iterations of continuous FC faults.
>>
>> Reason here is that we're returning an I/O error whenever we're
>> encountering sense code 06/04/0a (LOGICAL UNIT NOT ACCESSIBLE,
>> ASYMMETRIC ACCESS STATE TRANSITION) instead of retrying.
>>> Signed-off-by: Hannes Reinecke <hare@suse.de>
>> ---
>>   drivers/scsi/scsi_error.c | 7 ++++---
>>   1 file changed, 4 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
>> index 03a2ff547b22..1185083105ae 100644
>> --- a/drivers/scsi/scsi_error.c
>> +++ b/drivers/scsi/scsi_error.c
>> @@ -594,10 +594,11 @@ enum scsi_disposition scsi_check_sense(struct scsi_cmnd *scmd)
>>   		    sshdr.asc == 0x3f && sshdr.ascq == 0x0e)
>>   			return NEEDS_RETRY;
>>   		/*
>> -		 * if the device is in the process of becoming ready, we
>> -		 * should retry.
>> +		 * if the device is in the process of becoming ready, or
>> +		 * transitions between ALUA states, we should retry.
>>   		 */
>> -		if ((sshdr.asc == 0x04) && (sshdr.ascq == 0x01))
>> +		if ((sshdr.asc == 0x04) &&
>> +		    (sshdr.ascq == 0x01 || sshdr.ascq == 0x0a))
>>   			return NEEDS_RETRY;
> 
> Why put this here instead of in alua_check_sense with the other ALUA
> state transition check?
> 
Good point. Will be updating the patch.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
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