def get_device_number(mountpoint):
    device_number = _mountpoint_to_number(mountpoint)
    if device_number < 0:
        raise exception.StorageError(
                reason=_('Unable to obtain target information %s') %
                       mountpoint)
    return device_number
dataset/ETHPy150Open BU-NU-CLOUD-SP16/Trusted-Platform-Module-nova/nova/virt/xenapi/volume_utils.py/get_device_number/original