Re: [RFC][PATCH 4/4] Represent RPC Callers

[Matt Helsley <matthltc@us.ibm.com>]

On Tue, 2009-01-06 at 08:04 -0500, Trond Myklebust wrote:
> 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?

	I figured that the network latencies would be much larger than the
amount of time it takes to make a function call which, in the cases I
know of, would reduce to a strcpy().

Cheers,
	-Matt Helsley