locking change help

I am trying to change the lock manager so read locks will not be granted
if there is a write-lock waiting for a lock. The following patch helps,
but is incomplete. Can someone figure out the right fix? I tried
putting this code inside LockResolveConflicts(), but that didn't work
either.

---------------------------------------------------------------------------

*** ./backend/storage/lmgr/lock.c.orig Fri Jan 23 01:18:01 1998
--- ./backend/storage/lmgr/lock.c Fri Jan 23 01:18:53 1998
***************
*** 602,607 ****
--- 602,620 ----

status = LockResolveConflicts(ltable, lock, lockt, myXid);

+ /* ------------------------
+ * If someone with a greater priority is waiting for the lock,
+ * do not continue and share the lock, even if we can. bjm
+ * ------------------------
+ */
+ int myprio = ltable->ctl->prio[lockt];
+ PROC_QUEUE *waitQueue = &(lock->waitProcs);
+ PROC *topproc = (PROC *) MAKE_PTR(waitQueue->links.prev);
+
+ if (topproc && topproc->prio > myprio)
+ status = STATUS_FOUND;
+ }
+
if (status == STATUS_OK)
{
GrantLock(lock, lockt);

--
Bruce Momjian
maillist(at)candle(dot)pha(dot)pa(dot)us