Btrfs: make raid attr array more readable

The current code of raid attr arry is hard to understand and it is easy to
introduce some problem if we modify the array. So I changed it and made it
more readable.

Cc: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

1 files changed, 9 insertions, 13 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 82400b2b2517..174c4d5c692c 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -5545,20 +5545,16 @@ wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
 
 int __get_raid_index(u64 flags)
 {
-        int index;
-
         if (flags & BTRFS_BLOCK_GROUP_RAID10)
-                index = 0;
+                return BTRFS_RAID_RAID10;
         else if (flags & BTRFS_BLOCK_GROUP_RAID1)
-                index = 1;
+                return BTRFS_RAID_RAID1;
         else if (flags & BTRFS_BLOCK_GROUP_DUP)
-                index = 2;
+                return BTRFS_RAID_DUP;
         else if (flags & BTRFS_BLOCK_GROUP_RAID0)
-                index = 3;
+                return BTRFS_RAID_RAID0;
         else
-                index = 4;
-
-        return index;
+                return BTRFS_RAID_SINGLE;
 }
 
 static int get_block_group_index(struct btrfs_block_group_cache *cache)
@@ -7518,16 +7514,16 @@ int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
                 index = get_block_group_index(block_group);
         }
 
-        if (index == 0) {
+        if (index == BTRFS_RAID_RAID10) {
                 dev_min = 4;
                 /* Divide by 2 */
                 min_free >>= 1;
-        } else if (index == 1) {
+        } else if (index == BTRFS_RAID_RAID1) {
                 dev_min = 2;
-        } else if (index == 2) {
+        } else if (index == BTRFS_RAID_DUP) {
                 /* Multiply by 2 */
                 min_free <<= 1;
-        } else if (index == 3) {
+        } else if (index == BTRFS_RAID_RAID0) {
                 dev_min = fs_devices->rw_devices;
                 do_div(min_free, dev_min);
         }