Re: [PATCH 01/10] mdadm/Grow: Update new level when starting reshape

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

Hi Xiao,
Thanks for patches.

On Wed, 28 Aug 2024 10:11:41 +0800
Xiao Ni <xni@redhat.com> wrote:

> Reshape needs to specify a backup file when it can't update data offset
> of member disks. For this situation, first, it starts reshape and then
> it kicks off mdadm-grow-continue service which does backup job and
> monitors the reshape process. The service is a new process, so it needs
> to read superblock from member disks to get information.

Looks like kernel is fine with reset the same level so I don't see a risk in
this change for other scenarios but please mention that.

> 
> But in the first step, it doesn't update new level in superblock. So
> it can't change level after reshape finishes, because the new level is
> not right. So records the new level in the first step.

> 
> Signed-off-by: Xiao Ni <xni@redhat.com>
> ---
>  Grow.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/Grow.c b/Grow.c
> index 5810b128aa99..97e48d86a33f 100644
> --- a/Grow.c
> +++ b/Grow.c
> @@ -2946,6 +2946,9 @@ static int impose_reshape(struct mdinfo *sra,
>  		if (!err && sysfs_set_num(sra, NULL, "layout",
>  					  reshape->after.layout) < 0)
>  			err = errno;
> +		if (!err && sysfs_set_num(sra, NULL, "new_level",
> +					info->new_level) < 0)
> +			err = errno;

Please add empty line before and after and please merge if statement to one
line (we support up to 100).


>  		if (!err && subarray_set_num(container, sra, "raid_disks",
>  					     reshape->after.data_disks +
>  					     reshape->parity) < 0)


Thanks,
Mariusz