From mboxrd@z Thu Jan  1 00:00:00 1970
From: Oleg Nesterov <oleg-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Subject: Re: [REVIEW][PATCH 3/3] vfs: Fix a regression in mounting proc
Date: Wed, 27 Nov 2013 19:10:24 +0100
Message-ID: <20131127181024.GB29379@redhat.com>
References: <20131118031932.GA17621@mail.hallyn.com>
	<52899D09.5080202@cn.fujitsu.com>
	<20131118140830.GA22075@mail.hallyn.com>
	<20131118180134.GA24156@mail.hallyn.com>
	<87k3g5gnuv.fsf@xmission.com>
	<20131126181043.GA25492@mail.hallyn.com>
	<87siui1z1g.fsf_-_@xmission.com> <87pppmzoin.fsf_-_@xmission.com>
	<20131127161300.GA24773@redhat.com>
	<CALCETrXFnw63=JoEaQxM+Opj+kCXSL=9XppymzGKhLzOnp3WaQ@mail.gmail.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Return-path: <containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org>
Content-Disposition: inline
In-Reply-To: <CALCETrXFnw63=JoEaQxM+Opj+kCXSL=9XppymzGKhLzOnp3WaQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
List-Unsubscribe: <https://lists.linuxfoundation.org/mailman/options/containers>,
	<mailto:containers-request-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org?subject=unsubscribe>
List-Archive: <http://lists.linuxfoundation.org/pipermail/containers/>
List-Post: <mailto:containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org>
List-Help: <mailto:containers-request-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org?subject=help>
List-Subscribe: <https://lists.linuxfoundation.org/mailman/listinfo/containers>,
	<mailto:containers-request-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org?subject=subscribe>
Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org
Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org
To: Andy Lutomirski <luto-kltTT9wpgjJwATOyAt5JVQ@public.gmane.org>
Cc: Aditya Kali <adityakali-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>, Containers <containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org>, Linux FS Devel <linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, "Eric W. Biederman" <ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
List-Id: containers.vger.kernel.org

On 11/27, Andy Lutomirski wrote:
>
> On Wed, Nov 27, 2013 at 8:13 AM, Oleg Nesterov <oleg-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> wrote:
> > To all: sorry for noise, I can't comment this patch.
> >
> >
> > But Eric, could you please help me to understand? I am totally confused.
> >
> > So, afaics, initially (even after MS_KERNMOUNT) fs_fully_visible("proc")
> > should return false.
> >
> > After the normal "mout -t proc none /proc/" it becomes true.
> >
> > And it is still true after, say, "mount -t ramfs none /proc/sys" because
> > "ls -ld /proc/sys" shows ->i_nlink == 1.
>
> Grr.  mount -t ramfs none /proc/sys should make proc be not "fully visible".

This was one of the reasons for my question ;)

Oleg.