Re: [Patch v5] super1: fix sb->max_dev when adding a new disk in linear array

[NeilBrown <neilb@suse.com>]

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On Thu, May 25 2017, Lidong Zhong wrote:

> The value of sb->max_dev will always be increased by 1 when adding
> a new disk in linear array. It causes an inconsistence between each
> disk in the array and the "Array State" value of "mdadm --examine DISK"
> is wrong. For example, when adding the first new disk into linear array
> it will be:
>
> Array State : RAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
> ('A' == active, '.' == missing, 'R' == replacing)
>
> Adding the second disk into linear array it will be
>
> Array State : .AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
> ('A' == active, '.' == missing, 'R' == replacing)
>
> Signed-off-by: Lidong Zhong <lzhong@suse.com>

Reviewed-by: NeilBrown <neilb@suse.com>

Thanks,
NeilBrown

> ---
>  super1.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/super1.c b/super1.c
> index 2fcb814..86ec850 100644
> --- a/super1.c
> +++ b/super1.c
> @@ -1267,8 +1267,9 @@ static int update_super1(struct supertype *st, struct mdinfo *info,
>  				break;
>  		sb->dev_number = __cpu_to_le32(i);
>  		info->disk.number = i;
> -		if (max >= __le32_to_cpu(sb->max_dev))
> +		if (i >= max) {
>  			sb->max_dev = __cpu_to_le32(max+1);
> +		}
>  
>  		random_uuid(sb->device_uuid);
>  
> @@ -1293,7 +1294,11 @@ static int update_super1(struct supertype *st, struct mdinfo *info,
>  			}
>  		}
>  	} else if (strcmp(update, "linear-grow-update") == 0) {
> +		int max = __le32_to_cpu(sb->max_dev);
>  		sb->raid_disks = __cpu_to_le32(info->array.raid_disks);
> +		if (info->array.raid_disks > max) {
> +			sb->max_dev = __cpu_to_le32(max+1);
> +		}
>  		sb->dev_roles[info->disk.number] =
>  			__cpu_to_le16(info->disk.raid_disk);
>  	} else if (strcmp(update, "resync") == 0) {
> -- 
> 2.12.0

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