Btrfs: add basic infrastructure for selective balancing

This allows to have a separate set of filters for each chunk type
(data,meta,sys).  The code however is generic and switch on chunk type
is only done once.

This commit also adds a type filter: it allows to balance for example
meta and system chunks w/o touching data ones.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 882582385283..003e54216069 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -186,6 +186,17 @@ struct map_lookup {
 #define map_lookup_size(n) (sizeof(struct map_lookup) + \
                             (sizeof(struct btrfs_bio_stripe) * (n)))
 
+/*
+ * Restriper's general type filter
+ */
+#define BTRFS_BALANCE_DATA              (1ULL << 0)
+#define BTRFS_BALANCE_SYSTEM            (1ULL << 1)
+#define BTRFS_BALANCE_METADATA          (1ULL << 2)
+
+#define BTRFS_BALANCE_TYPE_MASK         (BTRFS_BALANCE_DATA |       \
+                                         BTRFS_BALANCE_SYSTEM |     \
+                                         BTRFS_BALANCE_METADATA)
+
 struct btrfs_balance_args;
 struct btrfs_balance_control {
         struct btrfs_fs_info *fs_info;