# Re: \[PATCH\] Allow level migration only for single-array container

- From: Jes Sorensen \<hidden\>
- Date: 2016-10-19 15:26:11 
- List: linux-raid
- Page: https://ratatoskr.run/linux-raid/2016/10/6633128
- Thread: https://ratatoskr.run/linux-raid/2016/10/6633128/t.md

```text
Mariusz Dabrowski [ref] writes:
> IMSM doesn't allow to change RAID level of array in container with two
> arrays but array count check is being done too late (after removing disks)
> and in some cases (e. g. RAID 0 and RAID 1 migrated to RAID 0) both arrays
> become degraded. This patch adds array count check before disks are being
> removed.
>
> Signed-off-by: Mariusz Dabrowski <redacted>
> ---
>  Grow.c | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
>
> diff --git a/Grow.c b/Grow.c
> index 628f0e7..bcd27f5 100755
> --- a/Grow.c
> +++ b/Grow.c
> @@ -777,6 +777,25 @@ int remove_disks_for_takeover(struct supertype *st,
>  	struct mdinfo *remaining;
>  	int slot;
>  
> +	if (st->ss->external) {
> +		int rv = 0;
> +		struct mdinfo *arrays = st->ss->container_content(st, NULL);
> +		/* containter_content returns list of arrays in container
> +		 * If arrays->next is not NULL it means that there are 2 arrays in
> +		 * container and operation should be blocked
> +		 */
> +		if (arrays) {
> +			if (arrays->next)
> +				rv = 1;
> +			sysfs_free(arrays);
> +			if (rv) {
> +				pr_err("Error. Cannot perform operation on /dev/%s\n", st->devnm);
> +				pr_err("For this operation it MUST be single array in container\n");
> +				return rv;
> +			}
> +		}
> +	}
> +

Applied, but do remember code is 80 characters wide - except for print
statements. I will fixup that comment line as part of applying it.

Thanks,
Jes
```