From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tvrtko Ursulin Subject: Re: Change in behaviour when unmounting recursive bind mounts Date: Thu, 28 Mar 2013 16:29:47 +0000 Message-ID: <1845538.MuH6UK6OzG@deuteros> References: <2987308.JNKpYDEnfV@deuteros> <1694652.5MYOe5IR6S@deuteros> <20130328153549.GP6400@ram.oc3035372033.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Cc: linux-kernel , linux-fsdevel@vger.kernel.org, Al Viro To: Ram Pai Return-path: In-Reply-To: <20130328153549.GP6400@ram.oc3035372033.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On Thursday 28 March 2013 23:35:49 Ram Pai wrote: > On Thu, Mar 28, 2013 at 01:05:56PM +0000, Tvrtko Ursulin wrote: > > Hi, > > > > On Thursday 28 March 2013 11:03:51 Ram Pai wrote: > > > I tried these commands on a 3.8.0-rc1+ kernel and did not find the > > > problem. Is this on a recent kernel? > > > > I am on Fedora 17 latest, but I've seen this problem with different > > kernels. Pretty sure from 3.5 something to 3.8 something. All Fedora > > flavoured. I will try vanilla soon. > > > > What I am not sure is whether this behaviour was there from the start (on > > Fedora 17). I *think* it started to happen later on, which would mean a > > potential userland change somehow causes it. > > > > Would that be at all possible with some mechanism? > > > > > > Previously unmounting the recursive bind target would not unmount the > > > > source, which to me looks like a more sensible outcome. > > > > > > yes. it should not unless they are peer-mounts, which in your case is > > > not. > > > > What are these and how to create them? > > These are mounts that are created by marking mount as shared, followed > by bind mount, followed by submount and then unmount. > > Documentation/filesystem/sharedsubtree.txt has the details. Knowing the right keywords certainly enabled me to hunt it down, thanks! Culprit is systemd as per following commit: http://cgit.freedesktop.org/systemd/systemd/commit/?id=b3ac5f8cb98757416d8660023d6564a7c411f0a0 Regards, Tvrtko