Subject: Re: [RFC][PATCH 4/4] Represent RPC Callers
From: Trond Myklebust <trond.myklebust@fys.uio.no>
To: Matt Helsley <matthltc@us.ibm.com>
Cc: Linux Containers <containers@lists.linux-foundation.org>,
       "J. Bruce Fields" <bfields@fieldses.org>,
       Cedric Le Goater <clg@fr.ibm.com>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
       linux-nfs@vger.kernel.org, Chuck Lever <chuck.lever@oracle.com>,
       "Eric W. Biederman" <ebiederm@xmission.com>,
       Linux Containers <containers@lists.osdl.org>
In-Reply-To: <20090106011315.229045829@us.ibm.com>
References: <20090106011314.534653345@us.ibm.com>
	 <20090106011315.229045829@us.ibm.com>
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Date: Tue, 06 Jan 2009 08:04:22 -0500
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On Mon, 2009-01-05 at 17:13 -0800, Matt Helsley wrote:
> plain text document attachment (move-rpc-client-nodename-cache.patch)
> Currently RPC needs to know the nodename (often the same as the hostname) which
> should be used for UNIX-style authentication and file-lock tracking. Because
> hostname can change between RPC calls and some sequences of RPC calls may
> require consistent names between calls RPC currently saves the nodename with
> the RPC client structure.
> 
> This is doesn't always work because RPC clients may be discarded over the
> lifetime of a higher level service -- like those that compose NFS. Specifically
> this is known to happen during shutdown.
> 
> Hence RPC should expect the nodename to be saved by the caller when sequences
> of RPC calls requiring consistent nodenames may be needed (e.g. NFS). To enable
> this we introduce an RPC caller structure that allows RPC to query the caller
> for this information.
> 
> This patch is not complete but is meant to indicate the direction I'm planning
> on going. I'd like to know if there are any objections or if anyone sees a
> better way to handle this.

You're planning on slowing down every RPC call in order to fix a problem
on client shutdown? Why?

Trond

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