Commit 089221d3 authored by Johannes Thumshirn's avatar Johannes Thumshirn Committed by David Sterba
Browse files

btrfs: factor out block mapping for RAID5/6 



Now that we have a container for the I/O geometry that has all the needed
information for the block mappings of RAID5 and RAID6, factor out a helper
calculating this information.

Signed-off-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent d9d4ce9f

fs/btrfs/volumes.c

+53 −42
Original line number Diff line number Diff line
@@ -6435,6 +6435,55 @@ static void map_blocks_raid10(struct btrfs_fs_info *fs_info, 
	io_geom->mirror_num = io_geom->stripe_index - old_stripe_index + 1;

}



static void map_blocks_raid56_write(struct btrfs_chunk_map *map,

				    struct btrfs_io_geometry *io_geom,

				    u64 logical, u64 *length)

{

	int data_stripes = nr_data_stripes(map);



	/*

	 * Needs full stripe mapping.

	 *

	 * Push stripe_nr back to the start of the full stripe For those cases

	 * needing a full stripe, @stripe_nr is the full stripe number.

	 *

	 * Originally we go raid56_full_stripe_start / full_stripe_len, but

	 * that can be expensive.  Here we just divide @stripe_nr with

	 * @data_stripes.

	 */

	io_geom->stripe_nr /= data_stripes;



	/* RAID[56] write or recovery. Return all stripes */

	io_geom->num_stripes = map->num_stripes;

	io_geom->max_errors = btrfs_chunk_max_errors(map);



	/* Return the length to the full stripe end. */

	*length = min(logical + *length,

		      io_geom->raid56_full_stripe_start + map->start +

		      btrfs_stripe_nr_to_offset(data_stripes)) -

		logical;

	io_geom->stripe_index = 0;

	io_geom->stripe_offset = 0;

}



static void map_blocks_raid56_read(struct btrfs_chunk_map *map,

				   struct btrfs_io_geometry *io_geom)

{

	int data_stripes = nr_data_stripes(map);



	ASSERT(io_geom->mirror_num <= 1);

	/* Just grab the data stripe directly. */

	io_geom->stripe_index = io_geom->stripe_nr % data_stripes;

	io_geom->stripe_nr /= data_stripes;



	/* We distribute the parity blocks across stripes. */

	io_geom->stripe_index =

		(io_geom->stripe_nr + io_geom->stripe_index) % map->num_stripes;



	if (io_geom->op == BTRFS_MAP_READ && io_geom->mirror_num < 1)

		io_geom->mirror_num = 1;

}



/*

 * Map one logical range to one or more physical ranges.

 *
@@ -6527,48 +6576,10 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op, 
	} else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {

		map_blocks_raid10(fs_info, map, &io_geom, dev_replace_is_ongoing);

	} else if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {

		int data_stripes = nr_data_stripes(map);



		if (op != BTRFS_MAP_READ || io_geom.mirror_num > 1) {

			/*

			 * Needs full stripe mapping.

			 *

			 * Push stripe_nr back to the start of the full stripe

			 * For those cases needing a full stripe, @stripe_nr

			 * is the full stripe number.

			 *

			 * Originally we go raid56_full_stripe_start / full_stripe_len,

			 * but that can be expensive.  Here we just divide

			 * @stripe_nr with @data_stripes.

			 */

			io_geom.stripe_nr /= data_stripes;



			/* RAID[56] write or recovery. Return all stripes */

			io_geom.num_stripes = map->num_stripes;

			io_geom.max_errors = btrfs_chunk_max_errors(map);



			/* Return the length to the full stripe end */

			*length = min(logical + *length,

				      io_geom.raid56_full_stripe_start +

					      map->start +

					      btrfs_stripe_nr_to_offset(

						      data_stripes)) -

				  logical;

			io_geom.stripe_index = 0;

			io_geom.stripe_offset = 0;

		} else {

			ASSERT(io_geom.mirror_num <= 1);

			/* Just grab the data stripe directly. */

			io_geom.stripe_index = io_geom.stripe_nr % data_stripes;

			io_geom.stripe_nr /= data_stripes;



			/* We distribute the parity blocks across stripes */

			io_geom.stripe_index =

				(io_geom.stripe_nr + io_geom.stripe_index) %

					map->num_stripes;

			if (op == BTRFS_MAP_READ && io_geom.mirror_num < 1)

				io_geom.mirror_num = 1;

		}

		if (op != BTRFS_MAP_READ || io_geom.mirror_num > 1)

			map_blocks_raid56_write(map, &io_geom, logical, length);

		else

			map_blocks_raid56_read(map, &io_geom);

	} else {

		/*

		 * After this, stripe_nr is the number of stripes on this