From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760468AbZAWJNd (ORCPT ); Fri, 23 Jan 2009 04:13:33 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753873AbZAWJNQ (ORCPT ); Fri, 23 Jan 2009 04:13:16 -0500 Received: from out4.smtp.messagingengine.com ([66.111.4.28]:47733 "EHLO out4.smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752713AbZAWJNO (ORCPT ); Fri, 23 Jan 2009 04:13:14 -0500 X-Sasl-enc: X8xm9vEodrELqWbHuz7jeUep4087+d7nMjuSpKbkpeEc 1232701992 Subject: Re: [PATCH] autofs4: turn ->oz_pgrp into "struct pid *" From: Ian Kent To: Oleg Nesterov Cc: Andrew Morton , hpa@zytor.com, Cedric Le Goater , Dave Hansen , Eric Biederman , Pavel Emelyanov , Serge Hallyn , Sukadev Bhattiprolu , linux-kernel@vger.kernel.org In-Reply-To: <20090123080617.GA4002@redhat.com> References: <20090118073449.GA707@redhat.com> <1232686627.3011.26.camel@zeus.themaw.net> <20090123080617.GA4002@redhat.com> Content-Type: text/plain Date: Fri, 23 Jan 2009 18:13:08 +0900 Message-Id: <1232701988.3011.42.camel@zeus.themaw.net> Mime-Version: 1.0 X-Mailer: Evolution 2.22.3.1 (2.22.3.1-1.fc9) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2009-01-23 at 09:06 +0100, Oleg Nesterov wrote: > On 01/23, Ian Kent wrote: > > > > On Sun, 2009-01-18 at 08:34 +0100, Oleg Nesterov wrote: > > > > > > I guess autofs4_show_options()->pid_vnr() is not exactly right, but hopefully > > > not worse than the current code. > > > > But shouldn't pid_vnr(sbi->oz_pgrp) report the pid as seen in the > > namespace of the calling process? In which case the only problem would > > be listing the mount table from a subordinate namespace that cannot see > > the process which did the mount, assuming fs namespace is not linked in > > some strict way to pid namespace, this could give an odd result. What > > might happen in this case Oleg? > > Yes, nothing bad can happen. pid_vnr() just returns 0 if the calling > process can't see the namespace. > > But I was worried about the case when, say, we are looking at > /subnamespace_root_mount/proc/mounts. > > In that case pid_vnr() will report the pid_t in the global namespace, > this differs from the case when this file is read by its own namespace > as /proc/mounts. > > I do not know whether this is right or not, though. Right, but mostly a source of confusion than anything else as things will still function OK. Not sure how to deal with that! Ian