Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755963AbaJHLJA (ORCPT ); Wed, 8 Oct 2014 07:09:00 -0400 Received: from relay.parallels.com ([195.214.232.42]:43456 "EHLO relay.parallels.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754192AbaJHLI6 (ORCPT ); Wed, 8 Oct 2014 07:08:58 -0400 Date: Wed, 8 Oct 2014 15:08:30 +0400 From: Andrew Vagin To: "Eric W. Biederman" CC: Andrey Vagin , , , , Andrey Vagin , Alexander Viro , Andrew Morton , Cyrill Gorcunov , Pavel Emelyanov , Serge Hallyn , Rob Landley Subject: Re: [PATCH] [RFC] mnt: add ability to clone mntns starting with the current root Message-ID: <20141008110829.GC24908@paralelels.com> References: <1412683977-29543-1-git-send-email-avagin@openvz.org> <87mw97wqvx.fsf@x220.int.ebiederm.org> MIME-Version: 1.0 Content-Type: text/plain; charset="koi8-r" Content-Disposition: inline In-Reply-To: <87mw97wqvx.fsf@x220.int.ebiederm.org> User-Agent: Mutt/1.5.23 (2014-03-12) X-Originating-IP: [10.30.16.48] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Oct 07, 2014 at 01:45:22PM -0700, Eric W. Biederman wrote: > Andrey Vagin writes: > > > From: Andrey Vagin > > > > Currently when we create a new container with a separate root, > > we need to clone the current mount namespace with all mounts and then > > clean up it by using pivot_root(). A big part of mountpoints are cloned > > only to be umounted. > > Is the motivation performance? Because if that is the motivation we > need numbers. The major motivation to create a clean mount namespace which contains only required mounts. Now you want to convince us that there is nothing wrong if we use userns, because all inherited mounts are locked. My point is that all useless mounts should be umounted. If the current root isn't on rootfs, pivot_root() allows us to umount all useless points. But pivot_root() doesn't work, if the current root is on rootfs. How can we umount useless points in this case? Maybe we want to say that rootfs should not be used if we are going to create containers... Thanks, Andrew -- 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/