From mboxrd@z Thu Jan  1 00:00:00 1970
From: "J. R. Okajima" <hooanon05@yahoo.co.jp>
Subject: vfs-scale, d_revalidate from nfsd
Date: Thu, 13 Jan 2011 23:03:56 +0900
Message-ID: <8855.1294927436@jrobl>
Cc: linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	linux-kernel@vger.kernel.org
To: Nick Piggin <npiggin@gmail.com>
Return-path: <linux-kernel-owner@vger.kernel.org>
Sender: linux-kernel-owner@vger.kernel.org
List-Id: linux-fsdevel.vger.kernel.org


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.


J. R. Okajima