Re: [PATCH v2 6/7] Allow changing the RWH policy for a running array

[Jes Sorensen <Jes.Sorensen@redhat.com>]

Artur Paszkiewicz <artur.paszkiewicz@intel.com> writes:
> This extends the --rwh-policy parameter to work also in Misc mode. Using
> it changes the currently active RWH policy in the kernel driver and
> updates the metadata to make this change permanent. Updating metadata is
> not yet implemented for super1, so this is limited to IMSM for now.
>
> Signed-off-by: Artur Paszkiewicz <artur.paszkiewicz@intel.com>

Hi Artur,

It looked good all the way up until 6/7, but there is a nit here:

> ---
>  Manage.c      | 79 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  mdadm.c       |  9 +++++++
>  mdadm.h       |  1 +
>  super-intel.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++-
>  4 files changed, 153 insertions(+), 1 deletion(-)
[snip]
> diff --git a/super-intel.c b/super-intel.c
> index e524ef0..3b40429 100644
> --- a/super-intel.c
> +++ b/super-intel.c
> @@ -448,6 +448,7 @@ enum imsm_update_type {
>  	update_general_migration_checkpoint,
>  	update_size_change,
>  	update_prealloc_badblocks_mem,
> +	update_rwh_policy,
>  };
>  
>  struct imsm_update_activate_spare {
> @@ -540,6 +541,12 @@ struct imsm_update_prealloc_bb_mem {
>  	enum imsm_update_type type;
>  };
>  
> +struct imsm_update_rwh_policy {
> +	enum imsm_update_type type;
> +	int new_policy;
> +	int dev_idx;
> +};
> +
>  static const char *_sys_dev_type[] = {
>  	[SYS_DEV_UNKNOWN] = "Unknown",
>  	[SYS_DEV_SAS] = "SAS",
> @@ -3175,7 +3182,6 @@ static void getinfo_super_imsm_volume(struct supertype *st, struct mdinfo *info,
>  	info->custom_array_size   <<= 32;
>  	info->custom_array_size   |= __le32_to_cpu(dev->size_low);
>  	info->recovery_blocked = imsm_reshape_blocks_arrays_changes(st->sb);
> -	info->journal_clean = dev->rwh_policy;
>  
>  	if (is_gen_migration(dev)) {
>  		info->reshape_active = 1;
> @@ -3347,6 +3353,8 @@ static void getinfo_super_imsm_volume(struct supertype *st, struct mdinfo *info,
>  			info->rwh_policy = RWH_POLICY_PPL;
>  		else
>  			info->rwh_policy = RWH_POLICY_UNKNOWN;
> +
> +		info->journal_clean = info->rwh_policy == RWH_POLICY_PPL;
>  	}
>  }

This part doesn't make sense, first you set info->rwh_policy based on
sb->feature_map to RWH_POLICY_PPL or RWH_POLICY_UNKNOWN and then right
after you hard set it to RWH_POLICY_PPL.

In general I really would prefer not to see any of those double
assignments if it can be avoided.

Cheers,
Jes