Re: Change in reported values of some block integrity sysfs attributes

[M Nikhil <nikh1092@linux.ibm.com>]

Thanks for the inputs Martin.

We have observed that even though the HBA does not support DIX Type, 
still the integrity attributes 'write_generate' and 'read_verify' are 
set to 1 for the block devices.


a3560030:~ # cat /sys/class/scsi_host/host0/prot_capabilities
0
a3560030:~ # cat /sys/class/scsi_host/host1/prot_capabilities
0


a3560030:~ # cat /sys/block/sdc/integrity/write_generate
1
a3560030:~ # cat /sys/block/sdc/integrity/read_verify
1


Thanks and Regards,

Nikhil

On 14/12/24 4:00 am, Martin K. Petersen wrote:
>> The sysfs attributes related to block device integrity ,
>> write_generate and read_verify are enabled for the block device when
>> the parameter device_is_integrity_capable is disabled.
> 'device_is_integrity_capable' is set if storage device (media) is
> formatted with PI.
>
> That is completely orthogonal to 'write_generate' and 'read_verify'
> which are enabled if the HBA supports DIX. If the HBA supports DIX Type
> 0, 'write_generate' and 'read_verify' are enabled even if the attached
> disk is not formatted with PI.
>
> I don't see any change in what's reported with block/for-next in a
> regular SCSI HBA/disk setup. Will have to look at whether there is a
> stacking issue wrt. multipathing.
>