From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752320Ab1LSQfq (ORCPT ); Mon, 19 Dec 2011 11:35:46 -0500 Received: from out01.mta.xmission.com ([166.70.13.231]:36879 "EHLO out01.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751414Ab1LSQfn (ORCPT ); Mon, 19 Dec 2011 11:35:43 -0500 From: ebiederm@xmission.com (Eric W. Biederman) To: Stanislav Kinsbursky Cc: "Trond.Myklebust\@netapp.com" , "linux-nfs\@vger.kernel.org" , Pavel Emelianov , "neilb\@suse.de" , "netdev\@vger.kernel.org" , "linux-kernel\@vger.kernel.org" , James Bottomley , "bfields\@fieldses.org" , "davem\@davemloft.net" , "devel\@openvz.org" References: <20111214103602.3991.20990.stgit@localhost6.localdomain6> <20111214104449.3991.61989.stgit@localhost6.localdomain6> <4EEEFC54.10700@parallels.com> <4EEF2C9A.8000403@parallels.com> Date: Mon, 19 Dec 2011 08:37:19 -0800 In-Reply-To: <4EEF2C9A.8000403@parallels.com> (Stanislav Kinsbursky's message of "Mon, 19 Dec 2011 16:22:50 +0400") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-XM-SPF: eid=;;;mid=;;;hst=in01.mta.xmission.com;;;ip=98.207.153.68;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX1/TMV7kot2kq+DNKALUeU1qq7B/IL48lgY= X-SA-Exim-Connect-IP: 98.207.153.68 X-SA-Exim-Mail-From: ebiederm@xmission.com X-Spam-Report: * 1.5 XMNoVowels Alpha-numberic number with no vowels * 0.0 T_TM2_M_HEADER_IN_MSG BODY: T_TM2_M_HEADER_IN_MSG * -3.0 BAYES_00 BODY: Bayes spam probability is 0 to 1% * [score: 0.0000] * -0.0 DCC_CHECK_NEGATIVE Not listed in DCC * [sa02 1397; Body=1 Fuz1=1 Fuz2=1] * 0.4 UNTRUSTED_Relay Comes from a non-trusted relay X-Spam-DCC: XMission; sa02 1397; Body=1 Fuz1=1 Fuz2=1 X-Spam-Combo: ;Stanislav Kinsbursky X-Spam-Relay-Country: ** Subject: Re: [PATCH 01/11] SYSCTL: export root and set handling routines X-Spam-Flag: No X-SA-Exim-Version: 4.2.1 (built Fri, 06 Aug 2010 16:31:04 -0600) X-SA-Exim-Scanned: Yes (on in01.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Stanislav Kinsbursky writes: >> In practice what this means is that register_net_sysctl_table should >> work for any sysctl file anywhere under /proc/sys. I think >> register_net_sysctl_table is the right solution for your problem. The >> only possible caveat I can think of is you might hit Al's performance >> optimizations and need to create a common empty directory first with >> register_sysctl_paths. > > Sorry, but I forgot to mention one more important goal I would like to achieve: > I want to manage sysctl's variables in context of mount owner, but not viewer one. > IOW imagine, that we have one two network namespaces: "A" and "B". Both of them > have it's own net sysctl's root. And we have per-net sysctl "/proc/sys/var". > And for ns "A" variable was set to 0, and for "B" - to 1. > And B's "/proc/sys/var" is accessible from "A" namespace > ("/chroot_path/proc/sys/var" for example). > With this configuration I want to read "1" from both namespaces: > owner "B" (/proc/sys/var) and "A" ("/chroot_path/proc/sys/var"). > Looks like simple using of register_net_sysctl_table doesn't allow me this, > because current net ns is used. And to achieve this goal I need my own sysctl > set for SUNRPC like it was done for network namespaces. Doing that independently of the rest of the sysctls is pretty horrible and confusing to users. What I am planning might suit your needs and if not we need to talk some more about how to get the vfs to do something reasonable. >> That said since I am in the process of rewriting things some of this >> may change a little bit, but hopefully not in ways that immediately >> effect the users of register_sysctl_table. >> >> Don't use register_net_sysctl_ro_table. I think what the implementors >> actually wanted was register_net_sysctl_table(&init_net, ...) and didn't >> know it. >> >> Don't put subdirectories in your sysctl tables. Use a ctl_path to >> specify the entire directory where the files should show up. Generally >> the code is easier to read in that form, and the code is simpler to deal >> with if we don't have to worry about directories. >> >> Don't play with the sysctl roots. It is my intention to completely kill >> them off and replace them by moving the per net sysctl tree under >> /proc//sys/. Leaving behind symlinks in /proc/sys/net and I guess >> ultimately in /proc/sys/sunrpc/ and /proc/sys/fs/nfs... Which actually >> seems to better describe your mental model. >> > > > I'm afraid, that this approach this not allow me to achieve the goal, mentioned > above, because current->nsproxy->net_ns will be used during lookup. > Or maybe I misunderstanding here? What I hope to do is to stop using current, and to behave like /proc/net. Aka a per process view under /proc//sys that matches the namespaces of the specified process. The VFS really hates my use of current in the sysctl case, and I intend to stop. I need to run and catch my plane. It doesn't look like I will have access to this email address for the next two weeks :( Eric