Re: [PATCH v2 blktests 2/2] nvme/059: add atomic write tests

[alan.adamson@oracle.com]

On 1/31/25 4:50 AM, Shinichiro Kawasaki wrote:
> On Jan 28, 2025 / 15:50, Alan Adamson wrote:
>> Tests basic atomic write functionality using NVMe devices
>> that support the AWUN and AWUPF Controller Atomic Parameters
>> and NAWUN and NAWUPF Namespace Atomic Parameters.
>>
>> Testing areas include:
>>
>> - Verify sysfs atomic write attributes are consistent with
>>    atomic write capablities advertised by the NVMe HW.
>>
>> - Verify the atomic write paramters of statx are correct using
>>    xfs_io.
>>
>> - Perform a pwritev2() (with and without RWF_ATOMIC flag) using
>>    xfs_io:
>>      - maximum byte size (atomic_write_unit_max_bytes)
>>      - a write larger than atomic_write_unit_max_bytes
> These test contests are smallre than those in scsi/009. Is it intentional?
> No "minimum byte size" test, and no "a write smaller than
> atomic_write_unit_min_bytes" test.

SCSI supports atomic writes a bit differently than NVMe.  SCSI has an 
atomic granularity which translates to a minimum write size when doing 
an atomic write.  NVMe doesn't have this concept and always guarantees 
writes of 1 block will be atomic so the additional tests aren't need for 
NVMe.

Alan