From: Al Viro <viro@ZenIV.linux.org.uk>
To: Nick Piggin <npiggin@gmail.com>
Cc: "J. R. Okajima" <hooanon05@yahoo.co.jp>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
linux-kernel@vger.kernel.org
Subject: Re: vfs-scale, d_revalidate from nfsd
Date: Fri, 14 Jan 2011 03:03:25 +0000 [thread overview]
Message-ID: <20110114030325.GU19804@ZenIV.linux.org.uk> (raw)
In-Reply-To: <AANLkTik1bj=Z9xFv8JfYrxqefFL1owmH=Rctj=XnH4Mp@mail.gmail.com>
On Fri, Jan 14, 2011 at 01:57:55PM +1100, Nick Piggin wrote:
> On Fri, Jan 14, 2011 at 1:03 AM, J. R. Okajima <hooanon05@yahoo.co.jp> wrote:
> >
> > NFSD calls filesystem's ->d_revalidate() with the parameter nd == NULL.
> > So every
> > ? ? ? ?if (nd->flags & LOOKUP_RCU)
> > ? ? ? ? ? ? ? ?return -ECHILD;
> > code which was added to ->d_revalidate() of FS which supports NFS
> > exporting will crash.
> >
> > If we rewrite it as
> > ? ? ? ?if (nd && (nd->flags & LOOKUP_RCU))
> > ? ? ? ? ? ? ? ?return -ECHILD;
> > the problem may not occur.
> > But I am not sure whether lookup_one_len() call in NFSD support rcu-walk.
>
> Ah, good catch.
>
> I'm going to change the d_revalidate API so it takes and inode and rcu-walk
> flag parameter to make it easier for filesystems to implement rcu-walk.
>
> That will take care of this NULL nd case.
Oh, for fuck sake... Would you at least mind posting your API change
description to fsdevel before going for it?
->d_revalidate() is one sick puppy and it's intimately involved in atomic
open rewrite. Please, *please* don't make that shit even messier...
next prev parent reply other threads:[~2011-01-14 3:03 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-13 14:03 vfs-scale, d_revalidate from nfsd J. R. Okajima
2011-01-14 2:57 ` Nick Piggin
2011-01-14 3:03 ` Al Viro [this message]
2011-01-14 3:12 ` Nick Piggin
2011-01-14 3:20 ` Al Viro
2011-01-14 3:22 ` Al Viro
2011-01-14 3:29 ` Nick Piggin
2011-01-14 3:38 ` Al Viro
2011-01-15 3:47 ` J. R. Okajima
2011-01-15 18:11 ` Nick Piggin
2011-02-15 5:07 ` J. R. Okajima
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