Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758064AbYJHAl6 (ORCPT ); Tue, 7 Oct 2008 20:41:58 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753972AbYJHAlu (ORCPT ); Tue, 7 Oct 2008 20:41:50 -0400 Received: from kroah.org ([198.145.64.141]:50428 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753163AbYJHAlu (ORCPT ); Tue, 7 Oct 2008 20:41:50 -0400 Date: Tue, 7 Oct 2008 17:38:34 -0700 From: Greg KH To: "Serge E. Hallyn" Cc: "Eric W. Biederman" , Al Viro , Benjamin Thery , linux-kernel@vger.kernel.org, Al Viro , Linus Torvalds , Tejun Heo Subject: Re: sysfs: tagged directories not merged completely yet Message-ID: <20081008003834.GA8680@kroah.com> References: <20080922153455.GA6238@kroah.com> <48D8FC1E.6000601@bull.net> <20081003101331.GH28946@ZenIV.linux.org.uk> <20081005053236.GA9472@kroah.com> <20081007222726.GA9465@kroah.com> <20081007225424.GA9430@us.ibm.com> <20081007233936.GA23282@kroah.com> <20081008001203.GA21918@us.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20081008001203.GA21918@us.ibm.com> User-Agent: Mutt/1.5.16 (2007-06-09) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2943 Lines: 66 On Tue, Oct 07, 2008 at 07:12:03PM -0500, Serge E. Hallyn wrote: > Quoting Greg KH (greg@kroah.com): > > On Tue, Oct 07, 2008 at 05:54:24PM -0500, Serge E. Hallyn wrote: > > > Quoting Greg KH (greg@kroah.com): > > > > On Tue, Oct 07, 2008 at 01:27:17AM -0700, Eric W. Biederman wrote: > > > > > Unless someone will give an example of how having multiple superblocks > > > > > sharing inodes is a problem in practice for sysfs and call it good > > > > > for 2.6.28. Certainly it shouldn't be an issue if the network namespace > > > > > code is compiled out. And it should greatly improve testing of the > > > > > network namespace to at least have access to sysfs. > > > > > > > > But if the network namespace code is in? THen we have problems, right? > > > > And that's the whole point here. > > > > > > > > The fact that you are trying to limit userspace view of in-kernel data > > > > structures, based on that specific user, is, in my opinion, crazy. > > > > > > > > Why not just keep all users from seeing sysfs, and then have a user > > > > daemon doing something on top of FUSE if you really want to see this > > > > kind of stuff. > > > > > > Well the blocker is really that when you create a new network namespace, > > > it wants to create a new loopback interface, but > > > /sys/devices/virtual/net/lo already exists. That's the same issue with > > > user namespace when the fair scheduler is enabled, which tries to > > > re-create /sys/kernel/uids/0. > > > > > > Otherwise yeah at least for my own uses, containers wouldn't need to > > > look at /sys at all. > > > > > > Heck you wouldn't even need FUSE, just mount -t tmpfs /sys/class/net > > > and manually link the right devices from /sys/devices/virtual/net. > > > > Great, that sounds like a solution. > > > > So tell me again why we need these huge sysfs reworks? :) > > Because : > > > > Well the blocker is really that when you create a new network namespace, No, wait. Why would you want to do such a thing in the first place? > > > it wants to create a new loopback interface, but > > > /sys/devices/virtual/net/lo already exists. That's the same issue with > > So at least we'd have to do something to allow creation of 'duplicate' > devices in different namespaces. It might be fine if we just ended up > with /sys/devices/virtual/net/lo, if created in a child net namespace, > be named /sys/devices/virtual/net/lo.childXYZ. Then userspace can > mount -t tmpfs none /sys/class/net and ln -s > /sys/devices/virtual/net/lo.childXYZ /sys/class/net/lo. ick. I agree with Tejun here, what's this whole network namespace stuff, what problems is it trying to solve and what are its goals? thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/