From mboxrd@z Thu Jan 1 00:00:00 1970 From: ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org (Eric W. Biederman) Subject: Re: [PATCH] userns: Allow the unprivileged users to mount mqueue fs Date: Sun, 27 Jan 2013 23:14:48 -0800 Message-ID: <877gmxye1j.fsf@xmission.com> References: <1359342541-383-1-git-send-email-gaofeng@cn.fujitsu.com> <87bocayntu.fsf@xmission.com> <51061F2F.6040104@cn.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <51061F2F.6040104-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org> (Gao feng's message of "Mon, 28 Jan 2013 14:48:15 +0800") List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Gao feng Cc: linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: containers.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