From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7843FC433E2 for ; Fri, 4 Sep 2020 14:29:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 10FAF20709 for ; Fri, 4 Sep 2020 14:29:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fieldses.org header.i=@fieldses.org header.b="qB37pzq6" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730270AbgIDO32 (ORCPT ); Fri, 4 Sep 2020 10:29:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60130 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730266AbgIDO30 (ORCPT ); Fri, 4 Sep 2020 10:29:26 -0400 Received: from fieldses.org (fieldses.org [IPv6:2600:3c00:e000:2f7::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E2742C061244 for ; Fri, 4 Sep 2020 07:29:25 -0700 (PDT) Received: by fieldses.org (Postfix, from userid 2815) id 29A841509; Fri, 4 Sep 2020 10:29:23 -0400 (EDT) DKIM-Filter: OpenDKIM Filter v2.11.0 fieldses.org 29A841509 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fieldses.org; s=default; t=1599229763; bh=dACq62FidyFRq/zUdggvXMM2CjkxwYUNeCEWUJxn/Wk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=qB37pzq63wtA7j2JxFESjsTRtZYwJzSbGXJJ0/a6GzppIZPjmWkXl6oEj9rRlpSjA yj7TCXLaIXkqGz4FX4b7+TzcWqYD8p11N3/yf23YyK8Lq9WE5W3s46jCLrDj7EiKgu j/cC9rwD62IyJP7RemRWPA83czNrfoZUqXrO7cvI= Date: Fri, 4 Sep 2020 10:29:23 -0400 From: Bruce Fields To: Chuck Lever Cc: Anna Schumaker , Bruce Fields , Linux NFS Mailing List Subject: Re: [PATCH v4 2/5] NFSD: Add READ_PLUS data support Message-ID: <20200904142923.GE26706@fieldses.org> References: <20200828212521.GA33226@pick.fieldses.org> <20200828215627.GB33226@pick.fieldses.org> <20200901164938.GC12082@fieldses.org> <20200901191854.GD12082@fieldses.org> <20200904135259.GB26706@fieldses.org> <00931C34-6C86-46A2-A3B3-9727DA5E739E@oracle.com> <20200904140324.GC26706@fieldses.org> <164C37D9-8044-4CF4-99A1-5FB722A16B8E@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <164C37D9-8044-4CF4-99A1-5FB722A16B8E@oracle.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org On Fri, Sep 04, 2020 at 10:07:22AM -0400, Chuck Lever wrote: > My primary concern is that the result of a file copy operation should > look the same on NFS/TCP (with READ_PLUS) and NFS/RDMA (with SEEK_DATA/HOLE). I'm not sure what you mean. I don't see the spec providing any guarantee of consistency between READ_PLUS and SEEK. It also doesn't guarantee that the results tell you anything about how the file is actually stored--a returned "hole" could represent an unallocated segment, or a fully allocated segment that's filled with zeroes, or some combination. So, for example, if you implemented an optimized copy that used ALLOCATE, DEALLOCATE, SEEK and/or READ_PLUS to avoid reading and writing a lot of zeroes--there's no guarantee that the target file would end up allocated in the same way as the source. --b.