From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757477Ab2DIQRp (ORCPT ); Mon, 9 Apr 2012 12:17:45 -0400 Received: from mx2.netapp.com ([216.240.18.37]:31295 "EHLO mx2.netapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756878Ab2DIQRn (ORCPT ); Mon, 9 Apr 2012 12:17:43 -0400 X-IronPort-AV: E=Sophos;i="4.75,393,1330934400"; d="scan'208";a="639512204" From: "Myklebust, Trond" To: "bfields@fieldses.org" CC: Stanislav Kinsbursky , Jeff Layton , "linux-nfs@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: Re: Grace period Thread-Topic: Grace period Thread-Index: AQHNFkNePLtNdDcBi0a9POplR1wLJZaS936AgAAKpACAABFIgIAAC4qAgAAAowCAAAGkAA== Date: Mon, 9 Apr 2012 16:17:06 +0000 Message-ID: <1333988226.2688.76.camel@lade.trondhjem.org> References: <4F7F230A.6080506@parallels.com> <20120406234039.GA20940@fieldses.org> <4F82C6E3.3030009@parallels.com> <20120409094743.56932677@tlielax.poochiereds.net> <4F82F16C.7030303@parallels.com> <20120409112739.6a823d6f@corrin.poochiereds.net> <4F830999.5000504@parallels.com> <20120409161114.GB6482@fieldses.org> In-Reply-To: <20120409161114.GB6482@fieldses.org> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.104.60.115] Content-Type: text/plain; charset="utf-8" Content-ID: MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by nfs id q39GHpg9018568 On Mon, 2012-04-09 at 12:11 -0400, bfields@fieldses.org wrote: > On Mon, Apr 09, 2012 at 08:08:57PM +0400, Stanislav Kinsbursky wrote: > > 09.04.2012 19:27, Jeff Layton пишет: > > > > > >If you allow one container to hand out conflicting locks while another > > >container is allowing reclaims, then you can end up with some very > > >difficult to debug silent data corruption. That's the worst possible > > >outcome, IMO. We really need to actively keep people from shooting > > >themselves in the foot here. > > > > > >One possibility might be to only allow filesystems to be exported from > > >a single container at a time (and allow that to be overridable somehow > > >once we have a working active/active serving solution). With that, you > > >may be able limp along with a per-container grace period handling > > >scheme like you're proposing. > > > > > > > Ok then. Keeping people from shooting themselves here sounds reasonable. > > And I like the idea of exporting a filesystem only from once per > > network namespace. > > Unfortunately that's not going to get us very far, especially not in the > v4 case where we've got the common read-only pseudoroot that everyone > has to share. I don't see how that can work in cases where each container has its own private mount namespace. You're going to have to tie that pseudoroot to the mount namespace somehow. -- Trond Myklebust Linux NFS client maintainer NetApp Trond.Myklebust@netapp.com www.netapp.com {.n++%ݶw{.n+{G{ayʇڙ,jfhz_(階ݢj"mG?&~iOzv^m ?I