linux-kernel - Re: [PATCH 2/3] enhanced syscall ESTALE error handling (v2)

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Message-Id: <E1JL3yn-0006KQ-AS@pomaz-ex.szeredi.hu>
Date:	Fri, 01 Feb 2008 23:03:25 +0100
From:	Miklos Szeredi <miklos@...redi.hu>
To:	staubach@...hat.com
CC:	miklos@...redi.hu, linux-kernel@...r.kernel.org,
	linux-nfs@...r.kernel.org, akpm@...ux-foundation.org,
	trond.myklebust@....uio.no, linux-fsdevel@...r.kernel.org
Subject: Re: [PATCH 2/3] enhanced syscall ESTALE error handling (v2)

> > 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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