From mboxrd@z Thu Jan 1 00:00:00 1970 From: ebiederm@xmission.com (Eric W. Biederman) Subject: Re: [PATCH] vfs: Add setns support for the mount namespace Date: Fri, 18 May 2012 16:47:02 -0600 Message-ID: <87sjexp0nt.fsf@xmission.com> References: <4FAD0524.3000307@parallels.com> <4FAD0555.4090906@parallels.com> <87mx5e5tho.fsf_-_@xmission.com> <4FAE4C70.5000804@parallels.com> <20120518194417.GA14195@mail.hallyn.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Pavel Emelyanov , Al Viro , Daniel Lezcano , Linux Kernel Mailing List , Andrew Morton , "linux-fsdevel\@vger.kernel.org" , Miklos Szeredi To: "Serge E. Hallyn" Return-path: Received: from out01.mta.xmission.com ([166.70.13.231]:60728 "EHLO out01.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757228Ab2ERWr1 (ORCPT ); Fri, 18 May 2012 18:47:27 -0400 In-Reply-To: <20120518194417.GA14195@mail.hallyn.com> (Serge E. Hallyn's message of "Fri, 18 May 2012 19:44:17 +0000") Sender: linux-fsdevel-owner@vger.kernel.org List-ID: "Serge E. Hallyn" writes: > Quoting Pavel Emelyanov (xemul@parallels.com): >> On 05/12/2012 12:54 AM, Eric W. Biederman wrote: >> > >> > setns support for the mount namespace is a little tricky as an arbitrary >> > decision must be made about what to set fs->root and fs->pwd to, as >> > there is no expectation of a relationship between the two mount >> > namespaces. Therefore I arbitrarily find the root mount point, and >> > follow every mount on top of it to find the top of the mount stack. >> > Then I set fs->root and fs->pwd to that location. The topmost root of >> > the mount stack seems like a reasonable place to be. >> > >> > Bind mount support for the mount namespace inodes has the possibility of >> > creating circular dependencies between mount namespaces. Circular >> > dependencies can result in loops that prevent mount namespaces from >> > every being freed. I avoid creating those circular dependencies by >> > adding a sequence number to the mount namespace and require all bind >> > mounts be of a younger mount namespace into an older mount namespace. >> > >> > Add a helper function proc_ns_inode so it is possible to detect when we >> > are attempting to bind mound a namespace inode. >> > >> > Signed-off-by: Eric W. Biederman >> >> Acked-by: Pavel Emelyanov > > These patches haven't made it into linux-next or Linus' tree. (More > worrisome, is that the several online linux-kernel mail archives I've > checked seem to have most of this thread, but not Eric's original > patch.) What path were they expected to go in by? I was hoping Al Viro would pick it up in the vfs tree, or at least review the patch. With a backup possibility that Andrew Morton might. Given that the merge window is likely to open in next couple of days I plan to resubmit this after the merge window closes. I don't have a clue what happened to the archives that day but it does look like there was a significant mail hiccup as the number of messages archived are way down. Eric