btrfs: use ncopies from btrfs_raid_array in btrfs_num_copies()

For all non-RAID56 profiles, we can use btrfs_raid_array[].ncopies
directly, only for RAID5 and RAID6 we need some extra handling as
there's no table value for that.

For RAID10 there's a change from sub_stripes to ncopies. The values are
the same but semantically we want to use number of copies, as this is
what btrfs_num_copies does.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Qu Wenruo <wqu@suse.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 e40c0d5..80636fb 100644 (file)
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -5717,7 +5717,8 @@ int btrfs_num_copies(struct btrfs_fs_info *fs_info, u64 logical, u64 len)
 {
        struct extent_map *em;
        struct map_lookup *map;
-       int ret;
+       enum btrfs_raid_types index;
+       int ret = 1;
 
        em = btrfs_get_chunk_map(fs_info, logical, len);
        if (IS_ERR(em))
@@ -5730,10 +5731,11 @@ int btrfs_num_copies(struct btrfs_fs_info *fs_info, u64 logical, u64 len)
                return 1;
 
        map = em->map_lookup;
-       if (map->type & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1_MASK))
-               ret = map->num_stripes;
-       else if (map->type & BTRFS_BLOCK_GROUP_RAID10)
-               ret = map->sub_stripes;
+       index = btrfs_bg_flags_to_raid_index(map->type);
+
+       /* Non-RAID56, use their ncopies from btrfs_raid_array. */
+       if (!(map->type & BTRFS_BLOCK_GROUP_RAID56_MASK))
+               ret = btrfs_raid_array[index].ncopies;
        else if (map->type & BTRFS_BLOCK_GROUP_RAID5)
                ret = 2;
        else if (map->type & BTRFS_BLOCK_GROUP_RAID6)
@@ -5745,8 +5747,6 @@ int btrfs_num_copies(struct btrfs_fs_info *fs_info, u64 logical, u64 len)
                 * stripe under reconstruction.
                 */
                ret = map->num_stripes;
-       else
-               ret = 1;
        free_extent_map(em);
 
        down_read(&fs_info->dev_replace.rwsem);