def _mount_filesystem(dev_path, dir):
    try:
        _out, err = utils.execute('mount',
                                 '-t', 'ext2,ext3,ext4,reiserfs',
                                 dev_path, dir, run_as_root=True)
    except processutils.ProcessExecutionError as e:
        err = six.text_type(e)
    return err
mounts the device specified by dev_path in dir.
dataset/ETHPy150Open BU-NU-CLOUD-SP16/Trusted-Platform-Module-nova/nova/virt/xenapi/vm_utils.py/_mount_filesystem