From: Jamie Lokier <jamie@shareable.org>
To: Jeff Layton <jlayton@redhat.com>
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-nfs@vger.kernel.org, adobriyan@gmail.com,
viro@ZenIV.linux.org.uk
Subject: Re: [PATCH] proc: revalidate dentry returned by proc_pid_follow_link
Date: Fri, 6 Nov 2009 20:36:01 +0000 [thread overview]
Message-ID: <20091106203601.GD27751@shareable.org> (raw)
In-Reply-To: <1257513594-31071-1-git-send-email-jlayton@redhat.com>
Jeff Layton wrote:
> The problem here is that this makes that code shortcut any lookup or
> revalidation of the dentry. In general, this isn't a problem -- in most
> cases the dentry is known to be good. It is a problem however for NFSv4.
> If this symlink is followed on an open operation no actual open call
> occurs and the open state isn't properly established. This causes
> problems when we later try to use this file descriptor for actual
> operations.
As NFS uses open() as a kind of fcntl-lock barrier, I can see it's
important to do _something_ on new opens, rather than just cloning
most of the file descriptor.
> This patch takes a minimalist approach to fixing this by making the
> /proc/pid follow_link routine revalidate the dentry before returning it.
What happens if the file descriptor you are re-opening is for a file
which has been deleted. Does it still have a revalidatable dentry?
-- Jamie
next prev parent reply other threads:[~2009-11-06 20:36 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-06 13:19 [PATCH] proc: revalidate dentry returned by proc_pid_follow_link Jeff Layton
2009-11-06 13:19 ` Jeff Layton
2009-11-06 20:36 ` Jamie Lokier [this message]
2009-11-06 21:06 ` Jeff Layton
2009-11-06 21:06 ` Jeff Layton
2009-11-08 10:15 ` Eric W. Biederman
[not found] ` <m17hu1miea.fsf-+imSwln9KH6u2/kzUuoCbdi2O/JbrIOy@public.gmane.org>
2009-11-09 1:12 ` Jeff Layton
2009-11-09 1:12 ` Jeff Layton
2009-11-09 1:12 ` Jeff Layton
[not found] ` <20091108201237.79af5cac-PC62bkCOHzGdMjc06nkz3ljfA9RmPOcC@public.gmane.org>
2009-11-09 3:30 ` Eric W. Biederman
2009-11-09 3:30 ` Eric W. Biederman
2009-11-09 3:30 ` Eric W. Biederman
[not found] ` <m1hbt49xxs.fsf-+imSwln9KH6u2/kzUuoCbdi2O/JbrIOy@public.gmane.org>
2009-11-09 13:11 ` Jeff Layton
2009-11-09 13:11 ` Jeff Layton
2009-11-09 13:11 ` Jeff Layton
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