Btrfs: add basic restriper infrastructure

Add basic restriper infrastructure: extended balancing ioctl and all
related ioctl data structures, add data structure for tracking
restriper's state to fs_info, etc.  The semantics of the old balancing
ioctl are fully preserved.

Explicitly disallow any volume operations when balance is in progress.

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

1 files changed, 13 insertions, 1 deletions

diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 78f2d4d4f37f..882582385283 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)))
 
+struct btrfs_balance_args;
+struct btrfs_balance_control {
+        struct btrfs_fs_info *fs_info;
+
+        struct btrfs_balance_args data;
+        struct btrfs_balance_args meta;
+        struct btrfs_balance_args sys;
+
+        u64 flags;
+};
+
 int btrfs_account_dev_extents_size(struct btrfs_device *device, u64 start,
                                    u64 end, u64 *length);
 
@@ -228,7 +239,8 @@ struct btrfs_device *btrfs_find_device(struct btrfs_root *root, u64 devid,
                                        u8 *uuid, u8 *fsid);
 int btrfs_shrink_device(struct btrfs_device *device, u64 new_size);
 int btrfs_init_new_device(struct btrfs_root *root, char *path);
-int btrfs_balance(struct btrfs_root *dev_root);
+int btrfs_balance(struct btrfs_balance_control *bctl,
+                  struct btrfs_ioctl_balance_args *bargs);
 int btrfs_chunk_readonly(struct btrfs_root *root, u64 chunk_offset);
 int find_free_dev_extent(struct btrfs_trans_handle *trans,
                          struct btrfs_device *device, u64 num_bytes,