Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!samsung!munnari.oz.au!metro!cluster!jaa
From: jaa@cluster.cs.su.oz.au (James Ashton)
Newsgroups: comp.sys.mips
Subject: rpc.lockd
Message-ID: <2383@cluster.cs.su.oz.au>
Date: 3 May 91 08:37:32 GMT
Organization: Dept. of Comp. Science, Uni of Sydney, Australia
Lines: 31

There seem to be a large number of bugs with this programme.  We have
found the following problems using fcntl to gain advisory exclusive
locks across multiple hosts.

Occasionally, locks are granted to many local processes simultaneously
for a file while locking for the same file operates correctly on remote
hosts.

When rpc.lockd is not running (it occasionally dies), processes which
request locks block permanently and cannot be killed.

Sometimes rpc.lockd consumes vast numbers of mbufs which eventually
brings the machine down.

Where file systems are remotely mounted with different names, the files
are not considered to be the same.  E.g. we have two machines basser and
orthanc.  /usr/tmp/tmp on orthanc is nfs mounted as /n/orthanc/usr/tmp/tmp
on basser but it is possible to simultaneously gain exclusive locks
on this file from each machine.

Locks seem not to be reliably released when a process is killed while
holding a lock.

We have 4.51 installed and are close to changing over to 4.52 but
rpc.lockd is apparently not modified in the new release.  Has anyone
fixed up these problems which seem to make file locking fairly
difficult?  Are others having these problems or could it be something
incorrectly set up with our configuration?  Any information would
be appreciated.

						James Ashton.