Re: [PATCH] scsi: sd: retry command SYNC CACHE if format in progress

[Bart Van Assche <bvanassche@acm.org>]

On 8/8/24 8:44 PM, Yihang Li wrote:
> On 2024/8/9 3:09, Bart Van Assche wrote:
>> On 8/7/24 7:17 PM, Yihang Li wrote:
>>> If formatting a suspended disk (such as formatting with different DIF
>>> type), the SYNC CACHE command will fail because the disk is in the
>>> formatting process, which will cause the runtime_status of the disk to
>>> error and it is difficult for user to recover it.
>>>
>>> To solve the issue, retry the command until format command is finished.
>>
>> How is the format command submitted to the SCSI disk? Is that command
>> perhaps submitted as a SCSI pass-through command (SG_IO ioctl)?
>>
> 
> When formatting a suspended disk, the disk will be resuming first,
> and then the format command will submit to the disk through SG_IO ioctl.
> 
> When the disk is processing the formatting command, the system does not
> submit other commands to the disk. Therefore, the system attempts to suspend
> the disk again and sends the SYNC CACHE command. However, the SYNC CACHE
> command fails because the disk is being formatted.
> 
> Error info like:
> 
> [  669.925325] sd 6:0:6:0: [sdg] Synchronizing SCSI cache
> [  670.202371] sd 6:0:6:0: [sdg] Synchronize Cache(10) failed: Result: hostbyte=0x00 driverbyte=DRIVER_OK
> [  670.216300] sd 6:0:6:0: [sdg] Sense Key : 0x2 [current]
> [  670.221860] sd 6:0:6:0: [sdg] ASC=0x4 ASCQ=0x4

Please consider integrating this information in the patch description.

>> Should the sd driver perhaps be unbound while the format command is in
>> progress?
>>
> 
> I do not have any suggestions for this yet. I don't know how to unbound driver
> when executing the format command and bound driver after the command is executed.
> 
> If you have any suggestions, please let me know.

It seems like the PCI core supports binding and unbinding through sysfs
but the SCSI core not. So it's probably easier to add support for
ASC/ASCQ 04h / 04h rather than to add bind/unbind support to the SCSI
core.

Thanks,

Bart.