'Confirms existence of the tmpfile under CONF.instances_path.
Cannot confirm tmpfile return False.'

def _check_shared_storage_test_file(self, filename, instance):

    os.utime(CONF.instances_path, None)
    tmp_file = os.path.join(CONF.instances_path, filename)
    if (not os.path.exists(tmp_file)):
        exists = False
    else:
        exists = True
    LOG.debug('Check    if    temp    file    %s    exists    to    indicate    shared    storage    is    being    used    for    migration.    Exists?    %s', tmp_file, exists, instance=instance)
    return exists
