Re: [PATCH -next 1/5] md/raid5: don't allow replacement while reshape is not done

[Yu Kuai]

Hi,

在 2023/05/20 7:33, Song Liu 写道:
> On Thu, May 11, 2023 at 6:59 PM Yu Kuai <yukuai1@xxxxxxxxxxxxxxx> wrote:
> > From: Yu Kuai <yukuai3@xxxxxxxxxx>
> >
> > Set rdev replacement has but not only two conditions:
> >
> > 1) MD_RECOVERY_RUNNING is not set;
> > 2) rdev nr_pending is 0;
>
> The above is confusing. I updated it and applied the set to md-next.

By the way, I'm willing to add regression test for these problems, and I
already send two other tests and there are no response yet. Should the
test wait for fixed patch to be applied to make progress?

Thanks,
Kuai
> Please let me know if it looks good.
>
> Thanks,
> Song
>
> > If reshape is interrupted(for example, echo frozen to sync_action), then
> > rdev replacement can be set. It's safe because reshape is always prior to
> > resync in md_check_recovery(). However, if system reboots, then kernel will
> > complain cannot handle concurrent replacement and reshape and this array
> > is not able to assemble anymore.
> >
> > Fix this problem by don't allow replacement until reshape is done.
> >
> > Reported-by: Peter Neuwirth <reddunur@xxxxxxxxx>
> > Link: https://lore.kernel.org/linux-raid/e2f96772-bfbc-f43b-6da1-f520e5164536@xxxxxxxxx/
> > Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
> > ---
> >   drivers/md/raid5.c | 1 +
> >   1 file changed, 1 insertion(+)
> >
> > diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
> > index a58507a4345d..bd3b535c0739 100644
> > --- a/drivers/md/raid5.c
> > +++ b/drivers/md/raid5.c
> > @@ -8378,6 +8378,7 @@ static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev)
> >                  p = conf->disks + disk;
> >                  tmp = rdev_mdlock_deref(mddev, p->rdev);
> >                  if (test_bit(WantReplacement, &tmp->flags) &&
> > +                   mddev->reshape_position == MaxSector &&
> >                      p->replacement == NULL) {
> >                          clear_bit(In_sync, &rdev->flags);
> >                          set_bit(Replacement, &rdev->flags);
> > --
> > 2.39.2
> .