From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christopher Allen Wing Subject: Re: Direct VFS/SB Access and Private Submounting Date: Wed, 21 Mar 2007 10:51:05 -0400 (EDT) Message-ID: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Cc: linux-fsdevel@vger.kernel.org To: "John Anthony Kazos Jr." Return-path: Received: from srvr20.engin.umich.edu ([141.213.75.22]:63304 "EHLO srvr20.engin.umich.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932152AbXCUPW6 (ORCPT ); Wed, 21 Mar 2007 11:22:58 -0400 Received: from gx620.engin.umich.edu (IDENT:U2FsdGVkX18ieV+cHvJ0DEULHtbhOkX9Xbm0zxPaARo@gx620.engin.umich.edu [141.213.40.58]) by srvr20.engin.umich.edu (8.13.6/8.13.6) with ESMTP id l2LEvP4Y029764 for ; Wed, 21 Mar 2007 10:57:26 -0400 (EDT) Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org Hello, not sure if someone has written you back about this already, but what you are trying to do (look 'underneath' a mount point) can be done easily without kernel modifications. You can bind mount an existing filesystem to a new location, and examine its contents without following existing mount points. e.g. suppose you want to look at the directory on your root filesystem upon which /proc is mounted: # mount |grep 'on /proc type proc' none on /proc type proc (rw) this is what the root of the /proc filesystem looks like: # ls -ld /proc dr-xr-xr-x 200 root root 0 Mar 1 18:06 /proc Now, temporarily bind mount the root to someplace else: # mkdir /tmp/look # mount --bind / /tmp/look Now you can examine the directory underlying /proc in the root: # ls -ld /tmp/look/proc drwxr-xr-x 2 root root 4096 Sep 26 2005 /tmp/look/proc # umount /tmp/look In general I would assume that a package manager shouldn't be concerned about these types of things, since permanent mountpoints should always be mounted when a system is in its normal state, thus there would be no reason to care about what's 'underneath' a mountpoint. (If someone had root access, they could be hiding stuff there, but it they had root access they could do a whole lot of other bad things) -Chris Wing wingc@engin.umich.edu