From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755320AbbAOQ1q (ORCPT ); Thu, 15 Jan 2015 11:27:46 -0500 Received: from fieldses.org ([174.143.236.118]:57880 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752814AbbAOQ1o (ORCPT ); Thu, 15 Jan 2015 11:27:44 -0500 Date: Thu, 15 Jan 2015 11:27:42 -0500 From: "J. Bruce Fields" To: Ian Kent Cc: Kernel Mailing List , David Howells , Oleg Nesterov , Trond Myklebust , Benjamin Coddington , Al Viro , Jeff Layton , "Eric W. Biederman" Subject: Re: [RFC PATCH 0/5] Second attempt at contained helper execution Message-ID: <20150115162741.GA14902@fieldses.org> References: <20150114092704.30252.60446.stgit@pluto.fritz.box> <20150114215525.GB7071@fieldses.org> <20150114221011.GC7071@fieldses.org> <1421281572.2688.4.camel@pluto.fritz.box> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1421281572.2688.4.camel@pluto.fritz.box> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 15, 2015 at 08:26:12AM +0800, Ian Kent wrote: > On Wed, 2015-01-14 at 17:10 -0500, J. Bruce Fields wrote: > > > On Wed, Jan 14, 2015 at 05:32:22PM +0800, Ian Kent wrote: > > > > There are other difficulties to tackle as well, such as how to decide > > > > if contained helper execution is needed. For example, if a mount has > > > > been propagated to a container or bound into the container tree (such > > > > as with the --volume option of "docker run") the root init namespace > > > > may need to be used and not the container namespace. > > > > I think you have to go through each of the existing upcall examples and > > decide what's needed for each. > > > > At least for the nfsv4 idmapper I would've thought the namespace the > > mount was done in would be the right choice, hence my previous question. > > Probably but you don't necessarily know what namespace the mount was > done in. It may have been propagated from another namespace or (although > I don't think it works yet) bound from another container using the > volumes-from docker option. Name-id mappings should be associated with the superblock, I guess--so don't you store a pointer to the right thing there? --b. > > At least I believe that's a problem and I agree that, once a suitable > method of running helpers is found each case will need to be looked at. > > Ian > >