From: Massimo Dal Zotto <dz@cs.unitn.it>

lock.patch

        I have rewritten lock.c cleaning up the code and adding better
        assert checking I have also added some fields to the lock and
        xid tags for better support of user locks. There is also a new
        function which returns an array of pids owning a lock.
        I'm using this code from over six months and it works fine.