To: staubach@redhat.com
CC: miklos@szeredi.hu, linux-kernel@vger.kernel.org, linux-nfs@vger.kernel.org,
       akpm@linux-foundation.org, trond.myklebust@fys.uio.no,
       linux-fsdevel@vger.kernel.org
In-reply-to: <47A39471.4010105@redhat.com> (message from Peter Staubach on
	Fri, 01 Feb 2008 16:51:45 -0500)
Subject: Re: [PATCH 2/3] enhanced syscall ESTALE error handling (v2)
References: <4790C768.4080207@redhat.com> <47A387D4.70605@redhat.com> <E1JL3a0-0006H7-U3@pomaz-ex.szeredi.hu> <47A39471.4010105@redhat.com>
Message-Id: <E1JL3yn-0006KQ-AS@pomaz-ex.szeredi.hu>
From: Miklos Szeredi <miklos@szeredi.hu>
Date: Fri, 01 Feb 2008 23:03:25 +0100
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1386
Lines: 39

> > This doesn't apply to -mm, because the ro-mounts stuff touches a lot
> > of the same places as this patch.  You probably need to rebase this on
> > top of those changes.
> >
> >   
> >> This patch adds handling for the error, ESTALE, to the system
> >> calls which take pathnames as arguments.  The algorithm used
> >> is to detect that an ESTALE error has occurred during an
> >> operation subsequent to the lookup process and then to unwind
> >> appropriately and then to perform the lookup process again.
> >> Eventually, either the lookup process will return an error
> >> or a valid dentry/inode combination and then operation can
> >> succeed or fail based on its own merits.
> >>     
> >
> > If a broken NFS server or FUSE filesysem keeps returning ESTALE, this
> > goes into an infinite loop.  How are we planning to deal with that?
> >
> >   
> 
> Would you describe the situation that would cause the kernel to
> go into an infinite loop, please?

The patch basically does:

	do {
		...
		error = inode->i_op->foo()
		...
	} while (error == ESTALE);

What is the guarantee, that ->foo() will not always return ESTALE?

Miklos
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