From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753059AbZAFM1v (ORCPT ); Tue, 6 Jan 2009 07:27:51 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751594AbZAFM1m (ORCPT ); Tue, 6 Jan 2009 07:27:42 -0500 Received: from out02.mta.xmission.com ([166.70.13.232]:33723 "EHLO out02.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751662AbZAFM1l (ORCPT ); Tue, 6 Jan 2009 07:27:41 -0500 From: ebiederm@xmission.com (Eric W. Biederman) To: Christoph Hellwig Cc: Alexey Dobriyan , viro@zeniv.linux.org.uk, linux-kernel@vger.kernel.org, containers@lists.osdl.org, sds@tycho.nsa.gov, jmorris@namei.org Subject: Re: [PATCH 1/6] proc: implement support for automounts in task directories References: <20090105233241.GA3924@x200.localdomain> <20090106092114.GA11877@infradead.org> Date: Tue, 06 Jan 2009 04:20:55 -0800 In-Reply-To: <20090106092114.GA11877@infradead.org> (Christoph Hellwig's message of "Tue, 6 Jan 2009 04:21:14 -0500") Message-ID: User-Agent: Gnus/5.110006 (No Gnus v0.6) Emacs/21.4 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-XM-SPF: eid=;;;mid=;;;hst=mx04.mta.xmission.com;;;ip=24.130.11.59;;;frm=ebiederm@xmission.com;;;spf=neutral X-SA-Exim-Connect-IP: 24.130.11.59 X-SA-Exim-Rcpt-To: too long (recipient list exceeded maximum allowed size of 128 bytes) X-SA-Exim-Mail-From: ebiederm@xmission.com X-SA-Exim-Version: 4.2.1 (built Thu, 07 Dec 2006 04:40:56 +0000) X-SA-Exim-Scanned: No (on mx04.mta.xmission.com); Unknown failure Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Christoph Hellwig writes: > On Tue, Jan 06, 2009 at 02:32:41AM +0300, Alexey Dobriyan wrote: >> This is current version of /proc/net as separate file system patchset, >> rebased, etc. I'll put it into -next again when merge window closes. > > I still don't see the point for that. Why not /proc/nets/ with > symlinks from /proc//net into those? Simple really. /proc/nets/ is the other possible viable solution. Where netid is some pid value that we assign to the network namespace during unshare or clone. While there is precedent of using a pid value to identify a process group or a session it is a bit of a stretch to have it cover a namespace. When I talked it over with Al his preference was to for the current approach, and it happens to be my preference as well. It gives more control of naming policy to user space allowing us to avoid the maintenance pain that is sysfs where user space depends upon a fixed kernel naming policy (which makes change hard). It gives us a guarantee that we only have a single dentry tree for any given network namespace. It allows us to eventually separate out maintenance of proc/generic and proc/net, as inherently they have nothing in common. The only cost of this is that we actually use one of the rare but fully supported vfs features, on demand submounts. Beyond that proc has wanted to be several filesystems for ages, and doing it this way allows us to actually start splitting proc up without breaking backwards compatibility with out existing user space. Eric