btrfs: use raid_attr table to find profiles for integrity lowering

Replace open coded list of the profiles by selecting them from the
raid_attr table. The criteria are now more explicit, we need profiles
that have more than 1 copy of the data or can reconstruct the data with
a missing device.

Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 301e60b11dd08857ded94204daca9cc23d068e7f..71add22e041ade2628bd7c650ccc3fa5706ec347 100644 (file)
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -4110,11 +4110,16 @@ int btrfs_balance(struct btrfs_fs_info *fs_info,
                goto out;
        }
 
-       /* allow to reduce meta or sys integrity only if force set */
-       allowed = BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
-                       BTRFS_BLOCK_GROUP_RAID10 |
-                       BTRFS_BLOCK_GROUP_RAID5 |
-                       BTRFS_BLOCK_GROUP_RAID6;
+       /*
+        * Allow to reduce metadata or system integrity only if force set for
+        * profiles with redundancy (copies, parity)
+        */
+       allowed = 0;
+       for (i = 0; i < ARRAY_SIZE(btrfs_raid_array); i++) {
+               if (btrfs_raid_array[i].ncopies >= 2 ||
+                   btrfs_raid_array[i].tolerated_failures >= 1)
+                       allowed |= btrfs_raid_array[i].bg_flag;
+       }
        do {
                seq = read_seqbegin(&fs_info->profiles_lock);