Re: [PATCH RFC 1/1] md: Use pers->quiesce in mddev_suspend

[Mariusz Tkaczyk <mariusz.tkaczyk@linux.intel.com>]

On Tue,  5 Nov 2024 15:57:33 +0800
Xiao Ni <xni@redhat.com> wrote:

> 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.

Is issue fixed with this patch? Is is missing here :)
> 
> 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.

> 
> Fixes: b39f35ebe86d ("md: don't quiesce in mddev_suspend()")
> Signed-off-by: Xiao Ni <xni@redhat.com>
> ---
>  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);
> +

Shouldn't it be implemented as below? According to b39f35ebe86d, some levels are
not implementing this?

+	if (mddev->pers && mddev->pers->quiesce)
+		mddev->pers->quiesce(mddev, 1);

Is it reproducible with upstream kernel?

Thanks,
Mariusz