From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S936298AbcJ0Nuy (ORCPT <rfc822;w@1wt.eu>);
        Thu, 27 Oct 2016 09:50:54 -0400
Received: from bombadil.infradead.org ([198.137.202.9]:52312 "EHLO
        bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S936094AbcJ0Nur (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Thu, 27 Oct 2016 09:50:47 -0400
Date: Thu, 27 Oct 2016 05:32:19 -0700
From: Christoph Hellwig <hch@infradead.org>
To: Sagi Grimberg <sagi@grimberg.me>
Cc: Christoph Hellwig <hch@infradead.org>,
        Dave Chinner <david@fromorbit.com>, jgunthorpe@obsidianresearch.com,
        sbates@raithin.com, "Raj, Ashok" <ashok.raj@intel.com>,
        haggaie@mellanox.com, linux-rdma@vger.kernel.org,
        "linux-nvdimm@lists.01.org" <linux-nvdimm@ml01.01.org>,
        Jonathan Corbet <corbet@lwn.net>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        jim.macdonald@everspin.com, Stephen Bates <sbates@raithlin.com>,
        linux-block@vger.kernel.org, Linux MM <linux-mm@kvack.org>,
        Jens Axboe <axboe@fb.com>, David Woodhouse <dwmw2@infradead.org>
Subject: Re: [PATCH 0/3] iopmem : A block device for PCIe memory
Message-ID: <20161027123219.GA757@infradead.org>
References: <1476826937-20665-1-git-send-email-sbates@raithlin.com>
 <CAPcyv4gJ_c-6s2BUjsu6okR1EF53R+KNuXnOc5jv0fuwJaa3cQ@mail.gmail.com>
 <20161019184814.GC16550@cgy1-donard.priv.deltatee.com>
 <20161020232239.GQ23194@dastard>
 <20161021095714.GA12209@infradead.org>
 <76e957c9-8002-5a46-8111-269bb0401718@grimberg.me>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <76e957c9-8002-5a46-8111-269bb0401718@grimberg.me>
User-Agent: Mutt/1.6.1 (2016-04-27)
X-SRS-Rewrite: SMTP reverse-path rewritten from <hch@infradead.org> by bombadil.infradead.org. See http://www.infradead.org/rpr.html
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Thu, Oct 27, 2016 at 01:22:49PM +0300, Sagi Grimberg wrote:
> Christoph, did you manage to leap to the future and solve the
> RDMA persistency hole? :)
> 
> e.g. what happens with O_DSYNC in this model? Or you did
> a message exchange for commits?

Yes, pNFS calls this the layoutcommit.  That being said once we get a RDMA
commit or flush operation we could easily make the layoutcommit optional
for some operations.  There already is a precedence for the in the
flexfiles layout specification.