Re: [REGRESSION] v5.17-rc1+: FIFREEZE ioctl system call hangs

[Song Liu <song@kernel.org>]

On Mon, Aug 22, 2022 at 8:15 PM Thomas Deutschmann <whissi@whissi.de> wrote:
>
> On 2022-08-23 03:37, Song Liu wrote:
> > Thomas, have you tried to bisect with the fio repro?
>
> Yes, just finished:
>
> > d32d3d0b47f7e34560ae3c55ddfcf68694813501 is the first bad commit
> > commit d32d3d0b47f7e34560ae3c55ddfcf68694813501
> > Author: Christoph Hellwig
> > Date:   Mon Jun 14 13:17:34 2021 +0200
> >
> >     nvme-multipath: set QUEUE_FLAG_NOWAIT
> >
> >     The nvme multipathing code just dispatches bios to one of the blk-mq
> >     based paths and never blocks on its own, so set QUEUE_FLAG_NOWAIT
> >     to support REQ_NOWAIT bios.
>
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d32d3d0b47f7e34560ae3c55ddfcf68694813501
>
>
> So another NOWAIT issue -- similar to the bad commit which is causing
> the mdraid issue I already found
> (https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0f9650bd838efe5c52f7e5f40c3204ad59f1964d).
>
> Reverting the commit, i.e. deleting
>
>    blk_queue_flag_set(QUEUE_FLAG_NOWAIT, head->disk->queue);
>
> fixes the problem for me. Well, sort of. Looks like this will disable
> io_uring. fio reproducer fails with

My system doesn't have multipath enabled. I guess bisect will point to something
else here.

I am afraid we won't get more information from bisect.

Thanks,
Song

>
> > $ fio reproducer.fio
> > filename0: (g=0): rw=randwrite, bs=(R) 4096B-4096B, (W) 4096B-4096B, (T) 4096B-4096B, ioengine=io_uring, iodepth=1
> > fio-3.30
> > Starting 1 thread
> > fio: io_u error on file /srv/machines/fio/filename0.0.0: Operation not supported: write offset=12648448, buflen=4096
> > fio: pid=1585, err=95/file:io_u.c:1846, func=io_u error, error=Operation not supported
>
> My MariaDB reproducer also doesn't trigger the problem anymore, but
> probably for the same reason -- it cannot use io_uring anymore.
>