From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753226Ab3A1HPB (ORCPT ); Mon, 28 Jan 2013 02:15:01 -0500 Received: from out02.mta.xmission.com ([166.70.13.232]:59723 "EHLO out02.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751948Ab3A1HO5 (ORCPT ); Mon, 28 Jan 2013 02:14:57 -0500 From: ebiederm@xmission.com (Eric W. Biederman) To: Gao feng Cc: serge.hallyn@canonical.com, akpm@linux-foundation.org, containers@lists.linux-foundation.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org References: <1359342541-383-1-git-send-email-gaofeng@cn.fujitsu.com> <87bocayntu.fsf@xmission.com> <51061F2F.6040104@cn.fujitsu.com> Date: Sun, 27 Jan 2013 23:14:48 -0800 In-Reply-To: <51061F2F.6040104@cn.fujitsu.com> (Gao feng's message of "Mon, 28 Jan 2013 14:48:15 +0800") Message-ID: <877gmxye1j.fsf@xmission.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-AID: U2FsdGVkX1/Sc5LZpmJUn71Q6HSLWCslP/WNDP94FTI= X-SA-Exim-Connect-IP: 98.207.153.68 X-SA-Exim-Mail-From: ebiederm@xmission.com X-Spam-Report: * -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP * 0.1 XMSubLong Long Subject * 0.0 T_TM2_M_HEADER_IN_MSG BODY: T_TM2_M_HEADER_IN_MSG * -3.0 BAYES_00 BODY: Bayes spam probability is 0 to 1% * [score: 0.0002] * -0.0 DCC_CHECK_NEGATIVE Not listed in DCC * [sa06 1397; Body=1 Fuz1=1 Fuz2=1] X-Spam-DCC: XMission; sa06 1397; Body=1 Fuz1=1 Fuz2=1 X-Spam-Combo: ;Gao feng X-Spam-Relay-Country: Subject: Re: [PATCH] userns: Allow the unprivileged users to mount mqueue fs X-Spam-Flag: No X-SA-Exim-Version: 4.2.1 (built Wed, 14 Nov 2012 14:26:46 -0700) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Gao feng writes: > On 2013/01/28 11:43, Eric W. Biederman wrote: >> Gao feng writes: >> >>> This patch allow the unprivileged user to mount mqueuefs in >>> user ns. >>> >>> If two userns share the same ipcns,the files in mqueue fs >>> should be seen in both these two userns. >>> >>> If the userns has its own ipcns,it has its own mqueue fs too. >>> ipcns has already done this job well. >> >> I am a little dense. When does userspace actually mount a mqueuefs? >> My impression was that user space never needed to mount and actually >> never could mount a mqueuefs. MS_NO_USER isn't set so mounting a >> mqueuefs is possible but when does it happen and why? >> > > Actually the files which representative messgae queue in mqueuefs contains > some informations,such as QSIZE,NOTIFY,SIGNO,NOTIFY_PID. > > My workstation is Fedora 17,mqueuefs is mounted on /dev/mqueue by default. > So I think at lest this patch is needed by some people. I have just confirmed that the most you can do in a mounted mqueue fs is to create files message queues. Given that these filesystems exist anyway I don't see a problem. Applied thanks. Eric