From mboxrd@z Thu Jan 1 00:00:00 1970 From: ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org (Eric W. Biederman) Subject: Re: [RFC][PATCH] Devices visibility container Date: Wed, 26 Sep 2007 13:09:46 -0600 Message-ID: References: <46F77523.9020001@openvz.org> <46F8BD33.5040108@openvz.org> <1190820972.26982.359.camel@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: In-Reply-To: <1190820972.26982.359.camel@localhost> (Dave Hansen's message of "Wed, 26 Sep 2007 08:36:12 -0700") List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Dave Hansen Cc: Linux Containers , Paul Menage , Pavel Emelyanov List-Id: containers.vger.kernel.org Dave Hansen writes: > On Tue, 2007-09-25 at 07:30 -0600, Eric W. Biederman wrote: >> Pavel Emelyanov writes: >> > >> > Oh! Can you provide us an example when after the migration some >> > device's major+minor pair change on the same device? >> >> SCSI disks on a SAN. Network accessible block devices. >> All kinds of logical/virtual devices like ttys, the loop device, and >> ramdisks. >> >> It isn't especially frequent that something cares, but fundamentally >> the same issues apply. > > To be clear, this just covers cases where an application has > _internalized_ the device number, right? Also cases where you want to call mknod in the container. > Most applications should be pretty happy with the devices having > persistent device names across a restart, and we can do that with udev > and no kernel patching. Yes. But the applications that do internalize stat data from files aren't that uncommon. git, and backup software etc. There is also a fair bit of work that is needed to get sysfs and the hotplug events isolated, when we start allowing mknod etc. Basically if I figure if we are going to deal with this we need to handle the entire problem because these pieces are user visible. I don't think it is a great priority. Eric