What are the implications of "holds a lien"

CCS Rules 1972: Rule 33(2) states that A person appointed to a post on probation shall be entitled to leave under these rules as a temporary or a permanent Government servant according as his appointment is against a temporary or a permanent post: Provided that where such person already holds a lien on a permanent post before such appointment, he shall be entitled to leave under these rules as a permanent Government servant. My appointment is done against a permanent post. After satisfactory probation period of two years, I will be absorbed as a permanent employee. Hence, Shall I be treated as a permanent employee ? and accordingly I can apply for leave without pay for maximum period of 5 years. What does this "holds a lien" implies?