From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263370AbVGAPV0 (ORCPT ); Fri, 1 Jul 2005 11:21:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263367AbVGAPV0 (ORCPT ); Fri, 1 Jul 2005 11:21:26 -0400 Received: from frankvm.xs4all.nl ([80.126.170.174]:6071 "EHLO janus.localdomain") by vger.kernel.org with ESMTP id S263371AbVGAPUE (ORCPT ); Fri, 1 Jul 2005 11:20:04 -0400 Date: Fri, 1 Jul 2005 17:20:03 +0200 From: Frank van Maarseveen To: Miklos Szeredi Cc: frankvm@frankvm.com, akpm@osdl.org, aia21@cam.ac.uk, arjan@infradead.org, linux-kernel@vger.kernel.org Subject: Re: FUSE merging? Message-ID: <20050701152003.GA7073@janus> References: <1120129996.5434.1.camel@imp.csi.cam.ac.uk> <20050630124622.7c041c0b.akpm@osdl.org> <20050630222828.GA32357@janus> <20050701092444.GA4317@janus> <20050701120028.GB5218@janus> <20050701130510.GA5805@janus> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.1i X-Subliminal-Message: Use Linux! Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jul 01, 2005 at 03:21:59PM +0200, Miklos Szeredi wrote: > > > To require an empty stub to mount FUSE upon makes the whole picture > > cleaner: users are only able to extend the namespace _leaf_ nodes for > > themselves and processes they can send signals to: setuid programs > > which do not fully become root. The existing namespace [nodes] remains > > unchanged for everyone. > > It's not as simple. A filesystem can be mounted many times (either > with mount --bind, or just by mounting the same device on multiple > mountpoints). In this case you can't ensure, that a mountpoint will > remain a leaf node after being mounted on. I have bind-mounted / on /net/blabla I tried two experiments: mounting something under / and looking for it under /net/blabla mounting something under /net/blabla and looking for it under / The experiment was done with bind mounts and by mounting a USB stick (/dev/sdb1) and there was no auto propagation of mounts. (2.6.12-rc6) How can a leaf dir suddenly become non-leaf by a mount without an explicit mount command? -- Frank