linux-kernel - Re: Error mounting FC8 NFS server with 2.6.31-rc3 NFSv4 client.

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Date:	Wed, 22 Jul 2009 16:20:13 -0400
From:	Trond Myklebust <trond.myklebust@....uio.no>
To:	Andy Adamson <andros@...app.com>
Cc:	Ben Greear <greearb@...delatech.com>,
	linux-kernel <linux-kernel@...r.kernel.org>,
	linux-nfs@...r.kernel.org
Subject: Re: Error mounting FC8 NFS server with 2.6.31-rc3 NFSv4 client.

On Wed, 2009-07-22 at 15:49 -0400, Andy Adamson wrote:
> On Jul 21, 2009, at 5:17 PM, Trond Myklebust wrote:
> > Note that there is a bug remaining inside nfs4_init_session(): we
> > shouldn't be copying the rsize/wsize into the nfs_client if the latter
> > was already initialised.
> 
> The rsize/wsize is copied into the session prior to the create_session  
> call (triggered by the state management code you moved), and is used  
> for session negotiation. At this point the nfs_client cl_cons_state is  
> set to NFS_CS_SESSION_INITING (see nfs4_alloc_session), so the  
> nfs_client is not initialized.  The cl_cons_state is set to  
> NFS_CS_READY after a successful create_session call.

The call to nfs4_init_session() is in nfs4_create_server(). It can be
called several times _after_ the nfs_client has been initialised when
you mount more than one partition from the same NFS server.

If that is the case, and if you use different rsize/wsize values on
those different mounts, then you will end up clobbering the values of
fc_attrs.max_rqst_sz, and fc_attrs.max_resp_sz, having set them to the
wsize/rsize that was set by the very last mount call.

AFAICS, what you _should_ be doing in nfs4_init_session, is something
like

	if (clp->cl_session->fc_attrs.max_rqst_sz < server->wsize)
		clp->cl_session->fc_attrs.max_rqst_sz = server->wsize;

Trond

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