From: Pavel Machek <pavel@suse.cz>
To: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Alexander Viro <viro@math.psu.edu>,
Alan Cox <alan@lxorguk.ukuu.org.uk>,
Simon Richter <Simon.Richter@phobos.fachschaften.tu-muenchen.de>,
Jonathan Barker <jbarker@ebi.ac.uk>,
linux-kernel@vger.kernel.org
Subject: Re: VFS mediator?
Date: Mon, 18 Mar 2002 23:38:27 +0100 [thread overview]
Message-ID: <20020318223827.GD1740@atrey.karlin.mff.cuni.cz> (raw)
In-Reply-To: <E16lej0-0002FE-00@the-village.bc.nu> <Pine.GSO.4.21.0203141825070.329-100000@weyl.math.psu.edu> <20020318192502.GD194@elf.ucw.cz> <shs1yeha5b4.fsf@charged.uio.no>
Hi!
> >> * NFS (v2,v3): Portable. And that's the only good thing to say
> >> about it - it's stateless, it has messy semantics all over the
> >> place and implementing userland server requires a lot of glue.
>
> > Does not work... If you mount nfs server on localhost, you can
> > deadlock.
>
> Huh? Examples please? A hell of a lot of work has gone into ensuring
> that this cannot happen. I do most of my NFS client work on this sort
> of setup, so it had bloody well better work...
Okay, take userland nfs-server. (This thread was about userland
filesystems).
Then, make memory full of dirty pages. Imagine that nfs-server is
swapped-out by some bad luck. What you have is extremely nasty
deadlock, AFAICS. [To free memory you have to write out dirty data,
but you can't do that because you don't have enough memory for
nfs-server].
Pavel
--
Casualities in World Trade Center: ~3k dead inside the building,
cryptography in U.S.A. and free speech in Czech Republic.
next prev parent reply other threads:[~2002-03-18 22:39 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-03-14 14:52 Jonathan Barker
2002-03-14 23:09 ` Simon Richter
2002-03-14 23:33 ` Alan Cox
2002-03-15 0:00 ` Alexander Viro
2002-03-15 11:50 ` Simon Richter
2002-03-18 19:25 ` Pavel Machek
2002-03-18 22:18 ` Trond Myklebust
2002-03-18 22:38 ` Pavel Machek [this message]
2002-03-18 22:48 ` Trond Myklebust
2002-03-18 22:54 ` Pavel Machek
2002-03-18 23:05 ` Trond Myklebust
2002-03-19 0:15 ` Alan Cox
2002-03-18 22:29 ` Alexander Viro
2002-03-18 22:36 ` Pavel Machek
2002-03-15 14:28 ` Jonathan Barker
2002-03-19 13:45 Jesse Pollard
2002-03-19 21:24 ` Pavel Machek
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