linux-kernel - Re: [PATCH] Add "-e" option to rpc.gssd to allow error on ticket expiry. Try 2 with added man pages.

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Date:	Sat, 19 Nov 2011 00:37:08 +0200
From:	Trond Myklebust <Trond.Myklebust@...app.com>
To:	John Hughes <john@...vaedi.com>
Cc:	Jim Rees <rees@...ch.edu>, John Hughes <john@...va.COM>,
	linux-nfs@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Add "-e" option to rpc.gssd to allow error on ticket
 expiry. Try 2 with added man pages.

On Fri, 2011-11-18 at 23:33 +0100, John Hughes wrote: 
> On 11/18/2011 10:03 PM, Trond Myklebust wrote:
> > On Fri, 2011-11-18 at 15:57 -0500, Jim Rees wrote:
> >    
> >>
> >> The write() syscall doesn't indicate whether the data is safe or not.  That
> >> would be the close() syscall.
> >>      
> > fsync(). Which may succeed if the user renews their ticket first.
> > However you may still have data loss if dirty data has been lost because
> > of EKEYEXPIRED returns on the WRITE RPC call...
> >    
> Only if the write(2) returned EKEYEXPIRED, surely,

What part of "write is asynchronous" is so hard to understand?

> > Also, for the fsync() to return EKEYEXPIRED _after_ the user has renewed
> > their ticket would seem counter-intuitive to most people.
> >    
> 
> I would want to know if data was lost.
> 
> Intuition means nothing if I get an error.
> 
> If it were possible I'd like:
> 
> 1. write works
> 1a. WRITE RPC fails, data stays in cache
> 2. ticket renewed
> 3. fsync works, data written

Which is _exactly_ how it works today, so what is the problem?

-- 
Trond Myklebust
Linux NFS client maintainer

NetApp
Trond.Myklebust@...app.com
www.netapp.com

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