On Tue, Nov 5, 2024 at 4:14 PM Yu Kuai <yukuai1@xxxxxxxxxxxxxxx> wrote:
>
> Hi,
>
> 在 2024/11/05 15:57, Xiao Ni 写道:
> > One customer reports a bug: raid5 is hung when changing thread cnt
> > while resync is running. The stripes are all in conf->handle_list
> > and new threads can't handle them.
> >
> > Commit b39f35ebe86d ("md: don't quiesce in mddev_suspend()") removes
> > pers->quiesce from mddev_suspend/resume, then we can't guarantee sync
> > requests finish in suspend operation. One personality knows itself the
> > best. So pers->quiesce is a proper way to let personality quiesce.
>
> Do you mean that other than normal IO, raid5 expects sync IO to be done
> as well by mddev_suspend()? If so, we'd better add some comments as
> well.
Hi Kuai
Yes, before patch b39f35ebe86d, mddev suspend can guarantee all io
(normal io from filesystem and sync requests) finish. And raid5
conf->handle_list have normal io and sync io, so it should wait all
these io finish in suspend operation. I'll add more comments.
Regards
Xiao
>
> Thanks,
> Kuai
>
> >
> > Fixes: b39f35ebe86d ("md: don't quiesce in mddev_suspend()")
> > Signed-off-by: Xiao Ni <xni@xxxxxxxxxx>
> > ---
> > drivers/md/md.c | 6 ++++++
> > 1 file changed, 6 insertions(+)
> >
> > diff --git a/drivers/md/md.c b/drivers/md/md.c
> > index 67108c397c5a..7409ecb2df68 100644
> > --- a/drivers/md/md.c
> > +++ b/drivers/md/md.c
> > @@ -482,6 +482,9 @@ int mddev_suspend(struct mddev *mddev, bool interruptible)
> > return err;
> > }
> >
> > + if (mddev->pers)
> > + mddev->pers->quiesce(mddev, 1);
> > +
> > /*
> > * For raid456, io might be waiting for reshape to make progress,
> > * allow new reshape to start while waiting for io to be done to
> > @@ -514,6 +517,9 @@ static void __mddev_resume(struct mddev *mddev, bool recovery_needed)
> > percpu_ref_resurrect(&mddev->active_io);
> > wake_up(&mddev->sb_wait);
> >
> > + if (mddev->pers)
> > + mddev->pers->quiesce(mddev, 0);
> > +
> > if (recovery_needed)
> > set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
> > md_wakeup_thread(mddev->thread);
> >
>
