From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Serge E. Hallyn" Subject: Re: [PATCH 3/5] device_cgroup: keep track of local group settings Date: Thu, 6 Dec 2012 04:31:30 +0000 Message-ID: <20121206043130.GA22792@mail.hallyn.com> References: <20121127193501.255267751@napanee.usersys.redhat.com> <20121127193502.482004744@napanee.usersys.redhat.com> <20121129192945.GD26104@mail.hallyn.com> <20121129195942.GW32112@redhat.com> <20121129202608.GA26716@mail.hallyn.com> <20121129223111.GZ32112@redhat.com> <20121203180125.GA30637@mail.hallyn.com> <20121203190657.GD32112@redhat.com> Mime-Version: 1.0 Return-path: Content-Disposition: inline In-Reply-To: <20121203190657.GD32112-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Aristeu Rozanski Cc: "Serge E. Hallyn" , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Tejun Heo , Serge Hallyn , cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Quoting Aristeu Rozanski (aris-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org): > On Mon, Dec 03, 2012 at 06:01:25PM +0000, Serge E. Hallyn wrote: > > First, generally, I don't think 'allows' added to parent should be > > automatically propagated to descendents. > > that's what I think too and what I tried to do > > > In devcgroup_update_access: (around line 625) > > there is a period of time where cgroup members have > > default allow without the parent's exceptions. > > true, will fix that one and look for more cases > > > propagate_behavior (line 505): > > 1. doesn't follow the same ordering as devcgroup_update_access(), in > > particular cleaning exceptions before setting behavior. > > I see, will update that > > > 2. When changing a parent from deny to allow, I don't think children > > should be updated. > > I disagree on this one. since there'll be local preferences, it'll try > to revalidate them everytime there's a change. so, for example, an > exception that might not be possible now, will be possible when its > parent changes in a way that allows that. My concern is just practical - if I've started a bunch of containers, and another admin decides to make a change to the root devices cgroup, I don't want the container's device accesses now changing. Maybe that's better solved by having all of userspace sit in /system while containers and vms sit under /lxc and /libvirt... -serge