Re: [PATCH v3 05/13] generic/1226: Add atomic write test using fio crc check verifier

Ojaswin Mujoo
2025-08-08T06:01:03Z

On Mon, Aug 04, 2025 at 08:12:00AM +0100, John Garry wrote:
> On 02/08/2025 07:49, Ojaswin Mujoo wrote:
> > On Fri, Aug 01, 2025 at 09:23:46AM +0100, John Garry wrote:
> > > On 01/08/2025 07:41, Ojaswin Mujoo wrote:
> > > > Got it, I think I can make this test work for ext4 only but then it might
> > > > be more appropriate to run the fio tests directly on atomic blkdev and
> > > > skip the FS, since we anyways want to focus on the storage stack.
> > > >
> > > testing on ext4 will prove also that the FS and iomap behave correctly in
> > > that they generate a single bio per atomic write (as well as testing the
> > > block stack and below).
> > Okay, I think we are already testing those in the ext4/061 ext4/062
> > tests of this patchset. Just thought blkdev test might be useful to keep
> > in generic. Do you see a value in that or shall I just drop the generic
> > overlapping write tests?
>
> If you want to just test fio on the blkdev, then I think that is fine.
> Indeed, maybe such tests are useful in blktests also.

Okay, I think it is better suited for blktests, so I'll add it there.

>
> >
> > Also, just for the records, ext4 passes the fio tests ONLY because we use
> > the same io size for all threads. If we happen to start overlapping
> > RWF_ATOMIC writes with different sizes that can get torn due to racing
> > unwritten conversion.
>
> I'd keep the same io size for all threads in the tests.

Yep

Thanks,
Ojaswin
>
> Thanks,
> John