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, 6 insertions, 0 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 3f8f11e18b53..c4d98c8df5c5 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -934,6 +934,7 @@ struct btrfs_block_group_cache {
 struct reloc_control;
 struct btrfs_device;
 struct btrfs_fs_devices;
+struct btrfs_balance_control;
 struct btrfs_delayed_root;
 struct btrfs_fs_info {
         u8 fsid[BTRFS_FSID_SIZE];
@@ -1159,6 +1160,11 @@ struct btrfs_fs_info {
         u64 avail_metadata_alloc_bits;
         u64 avail_system_alloc_bits;
 
+        /* restriper state */
+        spinlock_t balance_lock;
+        struct mutex balance_mutex;
+        struct btrfs_balance_control *balance_ctl;
+
         unsigned data_chunk_allocations;
         unsigned metadata_ratio;