linux-kernel - Re: [PATCH RFC] vfs: make fstatat retry on ESTALE errors from getattr call

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Date:	Mon, 16 Apr 2012 15:43:04 -0400
From:	Scott Lovenberg <scott.lovenberg@...il.com>
To:	Jeff Layton <jlayton@...hat.com>
CC:	Bernd Schubert <bernd.schubert@...m.fraunhofer.de>,
	Malahal Naineni <malahal@...ibm.com>,
	linux-nfs@...r.kernel.org, linux-fsdevel@...r.kernel.org,
	linux-kernel@...r.kernel.org, pstaubach@...grid.com,
	miklos@...redi.hu, viro@...IV.linux.org.uk, hch@...radead.org,
	michael.brantley@...haw.com, sven.breuner@...m.fraunhofer.de
Subject: Re: [PATCH RFC] vfs: make fstatat retry on ESTALE errors from getattr
 call

On 4/16/2012 1:46 PM, Jeff Layton wrote:
> NFS will generally return a different error if the process catches a
> fatal signal, so a soft mount should not be necessary and is not
> recommended anyway...
>
> In any case, we loop indefinitely now in the NFS code when (for
> instance) there's a loss of communication. Users are not generally
> happy if that causes an error, since their applications start dying.
>
 From the peanut gallery, I've always set an infinite loop with an 
exponential backoff on the loss of communication.  IE, in some code I 
wrote for S3backer (a FUSE file system on top of Amazon EC3) a few years 
ago (committed by Archie Cobbs).

The trade off is that your applications will try to submit requests if 
you don't tell them "leave me alone, I can't service you now".  The more 
I think about it, the more it seems like failing silently.  Isn't the 
rule supposed to be "if you must fail, do it loudly and as soon as 
possible"?  Just my $0.02.  Take it as you will.
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