Btrfs: allow for canceling restriper

Implement an ioctl for canceling restriper.  Currently we wait until
relocation of the current block group is finished, in future this can be
done by triggering a commit.  Balance item is deleted and no memory
about the interrupted balance is kept.

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

1 files changed, 1 insertions, 0 deletions

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 8ce837407800..c23b82d8ec08 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2006,6 +2006,7 @@ struct btrfs_root *open_ctree(struct super_block *sb,
         mutex_init(&fs_info->balance_mutex);
         atomic_set(&fs_info->balance_running, 0);
         atomic_set(&fs_info->balance_pause_req, 0);
+        atomic_set(&fs_info->balance_cancel_req, 0);
         fs_info->balance_ctl = NULL;
         init_waitqueue_head(&fs_info->balance_wait_q);