Re: [PATCH 2/2] scsi: scsi_debug: Validate zone access for WRITE ATOMIC (16)

[John Garry <john.garry@linux.dev>]

On 9/17/26 17:10, Niklas Cassel wrote:
>>> Right now, I don't see why WRITE ATOMIC should not be allowed on a ZBC
>>> drive.
>>>
>>>
>> So what happens when the write pointer is not aligned with Atomic alignment? Are atomic writes just not permitted in that scenario?
> 
> You are the expert when it comes to atomic writes.
> 
> But I would imagine that a device that implements both WRITE ATOMIC and ZBC
> would set the atomic alignment to the physical block size.

Sure, that sounds like a sane implementation. But there is nothing in 
the SCSI spec which mandates this (as far as I remember).

Maybe I am just being pedantic here in expecting the SCSI specs to be 
specific about interoperability of these two features.

> 
> That way the write pointer in sequential write required zones would always be aligned to both.
> 
> I/Os too larger than MAXIMUM ATOMIC TRANSFER LENGTH could be invalid for WRITE ATOMIC, but could be valid for regular writes.
> 
> Anyway, I will probably just drop this patch when I respin, since Damien did not fancy it.
> 
> I will keep the fix that ensures that we mark the blocks written by WRITE ATOMIC are marked as mapped:
> https://lore.kernel.org/linux-scsi/12d01f4b-4d9f-4079-908d- 
> ede50f7a28b4@kernel.org/

ok, I'll check it.

Thanks!