Re: [PATCH] block: virtio-blk: Fix handling of zone append command completion

[Damien Le Moal <dlemoal@kernel.org>]

On 6/22/23 23:32, Suwan Kim wrote:
> On Tue, Jun 20, 2023 at 5:39 PM Damien Le Moal <dlemoal@kernel.org> wrote:
>>
>> The introduction of completion batching with commit 07b679f70d73
>> ("virtio-blk: support completion batching for the IRQ path") overlloked
>> handling correctly the completion of zone append operations, which
>> require an update of the request __sector field, as is done in
>> virtblk_request_done(): the function virtblk_complete_batch() only
>> executes virtblk_unmap_data() and virtblk_cleanup_cmd() without doing
>> this update. This causes problems with zone append operations, e.g.
>> zonefs complains about invalid zone append locations.
>>
> 
> Hi Damien Le Moal,
> 
> Unfortunately, this commit was reverted due to io hang.
> (afd384f0dbea2229fd11159efb86a5b41051c4a9)
> You can see the mail thread at the block layer mailing list.

There is no commit afd384f0dbea2229fd11159efb86a5b41051c4a9 in Linus tree. What
patch are you talking about ? Where is it ?

> We don't have a solution about io hang yet..
> So I have one question.
> Is there any possibility of virtblk-driver io hang on zoned devices
> without this patch?

If you are talking about the batch completion support being reverted, then my
fix patch is not necessary. The issue I fixed is not about IO hang but the fact
that completion processing was not identical for batch case vs non batch. That
led to breakage of the zone append command completion. The original support for
zone append without batch completion is fine.

> 
> Regards,
> Suwan Kim

-- 
Damien Le Moal
Western Digital Research