Re: [PATCH 2/4] dm-zoned: use array for superblock zones

[Bob Liu <bob.liu@oracle.com>]

On 3/27/20 3:14 PM, Hannes Reinecke wrote:
> Instead of storing just the first superblock zone and calculate
> the secondary relative to that we should be using an array for
> holding the superblock zones.
> 
> Signed-off-by: Hannes Reinecke <hare@suse.de>

Reviewed-by: Bob Liu <bob.liu@oracle.com>

> ---
>  drivers/md/dm-zoned-metadata.c | 34 +++++++++++++++++++++-------------
>  1 file changed, 21 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/md/dm-zoned-metadata.c b/drivers/md/dm-zoned-metadata.c
> index afce594067fb..dc1d17bc3bbb 100644
> --- a/drivers/md/dm-zoned-metadata.c
> +++ b/drivers/md/dm-zoned-metadata.c
> @@ -124,6 +124,7 @@ struct dmz_sb {
>  	sector_t		block;
>  	struct dmz_mblock	*mblk;
>  	struct dmz_super	*sb;
> +	struct dm_zone		*zone;
>  };
>  
>  /*
> @@ -150,7 +151,6 @@ struct dmz_metadata {
>  	/* Zone information array */
>  	struct dm_zone		*zones;
>  
> -	struct dm_zone		*sb_zone;
>  	struct dmz_sb		sb[2];
>  	unsigned int		mblk_primary;
>  	u64			sb_gen;
> @@ -937,16 +937,20 @@ static int dmz_lookup_secondary_sb(struct dmz_metadata *zmd)
>  
>  	/* Bad first super block: search for the second one */
>  	zmd->sb[1].block = zmd->sb[0].block + zone_nr_blocks;
> +	zmd->sb[1].zone = zmd->sb[0].zone + 1;
>  	for (i = 0; i < zmd->nr_rnd_zones - 1; i++) {
>  		if (dmz_read_sb(zmd, 1) != 0)
>  			break;
> -		if (le32_to_cpu(zmd->sb[1].sb->magic) == DMZ_MAGIC)
> +		if (le32_to_cpu(zmd->sb[1].sb->magic) == DMZ_MAGIC) {
> +			zmd->sb[1].zone += i;
>  			return 0;
> +		}
>  		zmd->sb[1].block += zone_nr_blocks;
>  	}
>  
>  	dmz_free_mblock(zmd, mblk);
>  	zmd->sb[1].mblk = NULL;
> +	zmd->sb[1].zone = NULL;
>  
>  	return -EIO;
>  }
> @@ -990,11 +994,9 @@ static int dmz_recover_mblocks(struct dmz_metadata *zmd, unsigned int dst_set)
>  	dmz_dev_warn(zmd->dev, "Metadata set %u invalid: recovering", dst_set);
>  
>  	if (dst_set == 0)
> -		zmd->sb[0].block = dmz_start_block(zmd, zmd->sb_zone);
> -	else {
> -		zmd->sb[1].block = zmd->sb[0].block +
> -			(zmd->nr_meta_zones << zmd->dev->zone_nr_blocks_shift);
> -	}
> +		zmd->sb[0].block = dmz_start_block(zmd, zmd->sb[0].zone);
> +	else
> +		zmd->sb[1].block = dmz_start_block(zmd, zmd->sb[1].zone);
>  
>  	page = alloc_page(GFP_NOIO);
>  	if (!page)
> @@ -1038,8 +1040,13 @@ static int dmz_load_sb(struct dmz_metadata *zmd)
>  	u64 sb_gen[2] = {0, 0};
>  	int ret;
>  
> +	if (!zmd->sb[0].zone) {
> +		dmz_dev_err(zmd->dev, "Primary super block zone not set");
> +		return -ENXIO;
> +	}
> +
>  	/* Read and check the primary super block */
> -	zmd->sb[0].block = dmz_start_block(zmd, zmd->sb_zone);
> +	zmd->sb[0].block = dmz_start_block(zmd, zmd->sb[0].zone);
>  	ret = dmz_get_sb(zmd, 0);
>  	if (ret) {
>  		dmz_dev_err(zmd->dev, "Read primary super block failed");
> @@ -1051,8 +1058,9 @@ static int dmz_load_sb(struct dmz_metadata *zmd)
>  	/* Read and check secondary super block */
>  	if (ret == 0) {
>  		sb_good[0] = true;
> -		zmd->sb[1].block = zmd->sb[0].block +
> -			(zmd->nr_meta_zones << zmd->dev->zone_nr_blocks_shift);
> +		if (!zmd->sb[1].zone)
> +			zmd->sb[1].zone = zmd->sb[0].zone + zmd->nr_meta_zones;
> +		zmd->sb[1].block = dmz_start_block(zmd, zmd->sb[1].zone);
>  		ret = dmz_get_sb(zmd, 1);
>  	} else
>  		ret = dmz_lookup_secondary_sb(zmd);
> @@ -1147,9 +1155,9 @@ static int dmz_init_zone(struct blk_zone *blkz, unsigned int idx, void *data)
>  		zmd->nr_useable_zones++;
>  		if (dmz_is_rnd(zone)) {
>  			zmd->nr_rnd_zones++;
> -			if (!zmd->sb_zone) {
> +			if (!zmd->sb[0].zone) {
>  				/* Super block zone */
> -				zmd->sb_zone = zone;
> +				zmd->sb[0].zone = zone;
>  			}
>  		}
>  	}
> @@ -2420,7 +2428,7 @@ int dmz_ctr_metadata(struct dmz_dev *dev, struct dmz_metadata **metadata)
>  		goto err;
>  
>  	/* Set metadata zones starting from sb_zone */
> -	zid = dmz_id(zmd, zmd->sb_zone);
> +	zid = dmz_id(zmd, zmd->sb[0].zone);
>  	for (i = 0; i < zmd->nr_meta_zones << 1; i++) {
>  		zone = dmz_get(zmd, zid + i);
>  		if (!dmz_is_rnd(zone))
>