Re: [PATCH v2] md/raid5: don't allow concurrent reshape with recovery

[Song Liu]

On Mon, May 29, 2023 at 6:37 AM Yu Kuai <yukuai1@xxxxxxxxxxxxxxx> wrote:
>
> From: Yu Kuai <yukuai3@xxxxxxxxxx>
>
> Commit 0aecb06e2249 ("md/raid5: don't allow replacement while reshape
> is in progress") fixes that replacement can be set if reshape is
> interrupted, which will cause that array can't be assembled.
>
> There is a similar problem on the other side, if recovery is
> interrupted, then reshape can start, which will cause the same problem.
>
> Fix the problem by not starting to reshape while recovery is still in
> progress.
>
> Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>

Applied to md-next.

Thanks,
Song

> ---
> Changes in v2:
>  - fix some typo in commit message.
>
>  drivers/md/raid5.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
>
> diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
> index 8686d629e3f2..6615abf54d3f 100644
> --- a/drivers/md/raid5.c
> +++ b/drivers/md/raid5.c
> @@ -8525,6 +8525,7 @@ static int raid5_start_reshape(struct mddev *mddev)
>         struct r5conf *conf = mddev->private;
>         struct md_rdev *rdev;
>         int spares = 0;
> +       int i;
>         unsigned long flags;
>
>         if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
> @@ -8536,6 +8537,13 @@ static int raid5_start_reshape(struct mddev *mddev)
>         if (has_failed(conf))
>                 return -EINVAL;
>
> +       /* raid5 can't handle concurrent reshape and recovery */
> +       if (mddev->recovery_cp < MaxSector)
> +               return -EBUSY;
> +       for (i = 0; i < conf->raid_disks; i++)
> +               if (rdev_mdlock_deref(mddev, conf->disks[i].replacement))
> +                       return -EBUSY;
> +
>         rdev_for_each(rdev, mddev) {
>                 if (!test_bit(In_sync, &rdev->flags)
>                     && !test_bit(Faulty, &rdev->flags))
> --
> 2.39.2
>