@wrap_check_policy
def unreserve_volume(self, context, volume):
    if (volume['status'] == 'attaching'):
        self.update(context, volume, {'status': 'available'})
@wrap_check_policy
def unreserve_volume(self, context, volume):
    if (volume['status'] == 'attaching'):
        self.update(context, volume, {'status': 'available'})