#val_type uint64_t
BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED
BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED
BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED
BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED
BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED