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: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index d5c55724666bc97744d1b91896afbabb97007719..19ad793e60fa935bb1c048ab689f088af4c553d8 100644 (file)
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -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