From: Bernd Schubert <bernd.schubert@pci.uni-heidelberg.de>
Subject: Re: protocol question
Date: Wed, 26 Jul 2006 13:56:38 +0200
Message-ID: <200607261356.38520.bernd.schubert@pci.uni-heidelberg.de>
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To: Trond Myklebust <trond.myklebust@fys.uio.no>
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[Sorry that I forgot a proper subject first]

Hi Trond,

thanks for your help,

On Wednesday 26 July 2006 13:43, Trond Myklebust wrote:
> On Wed, 2006-07-26 at 12:47 +0200, Bernd Schubert wrote:
[...]
> > Ethereal shows that the getattr gives the correct results, but the read
> > call gives an NFS3ERR_STALE.
> > Should the client in this case drop its filehandle cache and entirely
> > re-request the file from the server, or is the given i/o error ok?
>
> The ESTALE error is usually correct. The client should not be reopening
> the file unless it can guarantee that the file is the same as the one
> that was originally open()ed.

But the client returns an i/o error to the userspace, is this correct?

>
> > From the point of the server, I guess, it already should return the
> > NFS3ERR_STALE for the getattr call, shouldn't it? I will look into the
> > sources to see why it didn't. (unfs3 was compiled with inode generation
> > number support).
>
> Yes. Under the close-to-open caching model, the expectation is that the
> filehandle will remain valid from the moment the successful GETATTR call
> is sent in the first open() request until the last call to close(). If
> unfs3 is caching filehandles, then it needs to use something like
> inotify in order to figure out when to invalidate its cache.

Hmm, but the inode generation number should have changed, isn't it there fo=
r =

exactly this purpose? I also restarted unfs3 first, so it didn't have any =

filehandles cached.


Thanks again,
	Bernd

-- =

Bernd Schubert
Physikalisch Chemisches Institut / Theoretische Chemie
Universit=E4t Heidelberg
INF 229
69120 Heidelberg
e-mail: bernd.schubert@pci.uni-heidelberg.de

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