def _canonicalize_lv_path(lv_path):
    """Convert LV path to a (vg, lv) tuple"""
    if lv_path.startswith('/dev'):
        # '/dev/vg/lv'
        _, _, vg, lv = lv_path.split('/')
    else:
        # vg/lv
        vg, lv = lv_path.split('/')
    return vg, lv