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, 4 insertions, 0 deletions

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index f572c53dda4..60852217ce9 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3076,6 +3076,8 @@ void update_ioctl_balance_args(struct btrfs_fs_info *fs_info,
                 bargs->state |= BTRFS_BALANCE_STATE_RUNNING;
         if (atomic_read(&fs_info->balance_pause_req))
                 bargs->state |= BTRFS_BALANCE_STATE_PAUSE_REQ;
+        if (atomic_read(&fs_info->balance_cancel_req))
+                bargs->state |= BTRFS_BALANCE_STATE_CANCEL_REQ;
 
         memcpy(&bargs->data, &bctl->data, sizeof(bargs->data));
         memcpy(&bargs->meta, &bctl->meta, sizeof(bargs->meta));
@@ -3157,6 +3159,8 @@ static long btrfs_ioctl_balance_ctl(struct btrfs_root *root, int cmd)
         switch (cmd) {
         case BTRFS_BALANCE_CTL_PAUSE:
                 return btrfs_pause_balance(root->fs_info);
+        case BTRFS_BALANCE_CTL_CANCEL:
+                return btrfs_cancel_balance(root->fs_info);
         }
 
         return -EINVAL;