When the record title of real estate is encumbered by an undischarged mortgage, and the mortgagor and those having his estate in the premises have been in uninterrupted possession of such real estate for 20 years after the expiration of the time limited in the mortgage for the full performance of the conditions thereof, he or they, or any person having a freehold estate, vested or contingent in possession, reversion or remainder, in the land originally subject to the mortgage or in any undivided or any aliquot part thereof, or any interest therein which may eventually become a freehold estate, or any person who has conveyed such land or any such interest therein with covenants of title or warranty, may apply to the Superior Court in the county where the whole or any part of the mortgaged premises is situated, by complaint setting forth the facts and asking for a decree as hereinafter provided. If after notice to all persons interested as provided in section 6107, no evidence is offered of any payment within said 20 years or of any other act within said time, in recognition of its existence as a valid mortgage, the Superior Court upon hearing may enter a decree setting forth such facts and its findings in relation thereto, which decree shall within 30 days be recorded in the registry of deeds where the mortgage is recorded. Thereafter no action shall be brought by any person to enforce a title under said mortgage.