From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Waychison Subject: Re: [RFC][PATCH] rbind across namespaces Date: Mon, 23 May 2005 17:39:38 -0700 Message-ID: <429277CA.9050300@google.com> References: <1116627099.4397.43.camel@localhost> <1116660380.4397.66.camel@localhost> <20050521134615.GB4274@mail.shareable.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: linuxram@us.ibm.com, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, akpm@osdl.org, viro@parcelfarce.linux.theplanet.co.uk Return-path: Received: from 216-239-45-4.google.com ([216.239.45.4]:63902 "EHLO 216-239-45-4.google.com") by vger.kernel.org with ESMTP id S261256AbVEXAkn (ORCPT ); Mon, 23 May 2005 20:40:43 -0400 To: Miklos Szeredi In-Reply-To: Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org Miklos Szeredi wrote: >>>I still see a problem: what if old_nd.mnt is already detached, and >>>bind is non-recursive. Now it fails with EINVAL, though it used to >>>work (and I think is very useful). >> >>Hey, you just made another argument for not detaching mounts when the >>last task with that current->namespace exits, but instead detaching >>mounts when the last reference to any vfsmnt in the namespace is dropped. >> >>Hint :) > > > I have a better idea: > > - create a "dead_mounts" namespace. > - chain each detached mount's ->mnt_list on dead_mounts->list > - set mnt_namespace to dead_mounts > - export the list via proc through the usual mount list interface > > The last would be a nice bonus: I've always wanted to see the list of > detached, but not-yet destroyed mounts. > > Does anybody see a problem with that? > FWIW, all this stuff has already been done and posted here. Detachable chunks of vfsmounts: http://marc.theaimsgroup.com/?l=linux-fsdevel&m=109872862003192&w=2 'Soft' reference counts for manipulating vfsmounts without pinning them down: http://marc.theaimsgroup.com/?l=linux-kernel&m=109872797030644&w=2 Referencing vfsmounts in userspace using a file descriptor: http://marc.theaimsgroup.com/?l=linux-kernel&m=109871948812782&w=2 walking mountpoints in userspace: http://marc.theaimsgroup.com/?l=linux-kernel&m=109875012510262&w=2 attaching mountpoints in userspace: http://marc.theaimsgroup.com/?l=linux-fsdevel&m=109875063100111&w=2 detaching mountpoints in userspace: http://marc.theaimsgroup.com/?l=linux-kernel&m=109880051800963&w=2 getting info from a vfsmount: http://marc.theaimsgroup.com/?l=linux-kernel&m=109875135030473&w=2 Mike Waychison