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Date:      Thu, 14 Dec 2000 23:07:56 +0100
From:      Axel Thimm <Axel.Thimm@physik.fu-berlin.de>
To:        freebsd-current@freebsd.org
Cc:        freebsd-hackers@freebsd.org, "David E. Cross" <crossd@cs.rpi.edu>, vladimir-bsd-current@math.uic.edu, Brad Knowles <blk@skynet.be>, Andrew Gallatin <gallatin@cs.duke.edu>, Roman Shterenzon <roman@harmonic.co.il>, "Scot W. Hetzel" <hetzels@westbend.net>, Greg Lewis <glewis@trc.adelaide.edu.au>, cam <cam@bsdfr.org>, Erik Trulsson <ertr1013@student.uu.se>, Cy Schubert - ITSD Open Systems Group <Cy.Schubert@uumail.gov.bc.ca>, Jaap Akkerhuis <jaap@nic.nl>, Stephen Montgomery-Smith <stephen@math.missouri.edu>, Coleman Kane <cokane@one.net>, Jeff Fisher <jeff@jeffenstein.org>, ragnar@sysabend.org, Doug@gorean.org, dillon@backplane.com, Andrew Gordon <arg@arg1.demon.co.uk>, andrew@ugh.net.au, Carsten Urbach <Carsten.Urbach@physik.fu-berlin.de>, Tobias Burnus <Tobias.Burnus@physik.fu-berlin.de>, Wolfram Klaus <Wolfram.Klaus@physik.fu-berlin.de>
Subject:   rpc.lockd and true NFS locks?
Message-ID:  <20001214230756.A13794@pua.domain>

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Dear all,

rpc.lockd in FreeBSD suffers from a pubic server's lazyness --- It says it's
done the job, but never did anything besides talking...

Searching through the lists gives different stories. Some say that NFS locking
isn't really necessary, but what about locking critical situations like
delivering mail over NFS to FreeBSD homes? Procmail & fcntl made our computing
department especially unhappy, and we are wondering whether we can keep our
migration strategy (moving our homes to backuped FreeBSD boxes).

Some of the following quoted mails (consider this mail as a review, if you
like) give hope that some people were working on this (without obviously
having commited anything, as one can check in cvsweb).

Is this true? Has anyone any server side patches for FreeBSD? Is he/she
looking for guinea pigs? Anything is better than the current situation. Our
users are running away from our otherwise very comfortable FreeBSD homes. :(

On Mon, Apr 03, 2000 at 02:07:54PM +0200, Brad Knowles wrote:
> [...]
> 	Besides, file locking becomes impossible in -STABLE once you've
> mounted it with NFS (we don't have a working lockd, although work in this
> area is progressing in -CURRENT), and NFS writes generally suck when
> compared to local writes.
> [...]

On Fri, Apr 07, 2000 at 08:07:40PM -0400, David E. Cross wrote:
> I apologize profusely for the delay of this, but lockd-0.2 is out.
> The URL is: http://www.cs.rpi.edu/~crossd/FreeBSD/lockd-0.2.tar.gz
> [...]
> 5) this does not add the code to FreeBSD's kernel to request the NFS locks
>    (that is a job for people more skilled than I ;)
> [...]
On Sat, Apr 08, 2000 at 12:23:14AM -0400, David E. Cross wrote:
> [...]
> http://www.cs.rpi.edu/~crossd/FreeBSD/lockd-0.2a.tar.gz
> [...]

On Fri, Apr 07, 2000 at 08:44:33PM -0400, Andrew Gallatin wrote:
> This might be a bit touchy, but I'm rather curious -- how will the BSDI
> merger affect your lockd work?  It seems like your work on lockd
> (esp. client side & statd interoperation issues) could be speeded up if you
> had access to the BSDI sources..

On Tue, Sep 19, 2000 at 12:38:51PM +0200, Roman Shterenzon wrote:
> Quoting Andrew Gordon <arg@arg1.demon.co.uk>:
> > On Mon, 4 Sep 2000, Roman Shterenzon wrote:
> > > The rpc.lockd(8) is marked as broken in /etc/defaults/rc.conf in 4.1-R
> > > My question is - how bad is it broken?
> > The rpc.lockd in 4.x simply answers "Yes" to all locking requests, and
> > does not maintain any state.  This means that if your programs actually
> > need locking, running rpc.lockd will cause problems (file corruption etc).
> > 
> > On the other hand, if your programs don't need locking and are just making
> > the locking calls for the hell of it, rpc.lockd will allow these programs
> > to run rather than just hanging up.
> > 
> > There was talk a few months ago about someone having implemented NFS
> > locking properly, but I haven't heard any more since - check the mailing
> > list archives.
> > 
> > [I wrote the existing 'hack' implementation].

On Wed, Sep 20, 2000 at 09:28:36AM -0500, Scot W. Hetzel wrote:
> From: "Roman Shterenzon" <roman@harmonic.co.il>
> > On Tue, 19 Sep 2000 andrew@ugh.net.au wrote:
> > > [...] Someone (from something.edu, perhaps rpi.edu) posted a URL to one
> > > of the lists of a working but untested rpc.lockd. [...]

I believe that Andrew means "David E. Cross" <crossd@cs.rpi.edu>, but his
citation some lines above show that he hadn't worked in that direction.

> I kind of remember reading about it on the current mailing list.
> Current-Users: Has a working rpc.lockd been imported into CURRENT.  If it
> has, is there a possibility of getting it MFC'd to STABLE.

On Thu, Sep 21, 2000 at 11:02:25AM +0930, Greg Lewis wrote:
> Look through the freebsd-hackers archive.  There was an rpc.lockd
> implementation announced there looking for testers about a month or so
> before the 4.0 release.  The person who wrote it is David Cross who is now a
> FreeBSD committer I believe.
> 
> Thats my recollection anyway.  Unfortunately I haven't seen any recent
> followups.  At the time it was deemed too close to the 4.0 release.  If you
> do test it maybe you can prod David with the results and get it committed to
> -current.

On Wed, Nov 08, 2000 at 05:45:21PM +0100, Erik Trulsson wrote:
> On Wed, Nov 08, 2000 at 02:53:47PM +0100, cam wrote:
> > I have to use rpc.lockd on my NFS server (FreeBSD 4.0-STABLE) and I've
> > notice that it is broken with this line in /etc/defaults/rc.conf:
> > 113: rpc_lockd_enable="NO"               # Run NFS rpc.lockd (*broken!*) if nfs_server.
> 
> You can't have looked that hard. This question did come up earlier this
> year on -questions and it wasn't difficult to find the answer searching
> through the list-archives.
> 
> Anyway, the answer is that lockd is just a dummy implementation. When the
> client requests a lock rpc.lockd will just say "A lock? Sure, here you have
> one." without actually locking anything. 
> 
> The only reason for running this is when you have semi-broken clients
> (usually DOS/Windows based) that insist on getting a lock even though they
> don't really need it. Then lockd will make them work.

This is not true, any true networked system might try to modify the same file,
think of mail delivery agents and Mail readers.

> ( I seem to remember somebody saying that there was work in progress
> writing a fully functional lockd. Has anything materialized on that
> front? (A quick check doesn't show anything in the repository.))

Thanks, Axel.
-- 
Axel.Thimm@physik.fu-berlin.de




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