Return-Path: linux-nfs-owner@vger.kernel.org Received: from smtp.opengridcomputing.com ([72.48.136.20]:37613 "EHLO smtp.opengridcomputing.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750702AbaENSX5 (ORCPT ); Wed, 14 May 2014 14:23:57 -0400 From: "Steve Wise" To: "'Chuck Lever'" Cc: "'J. Bruce Fields'" , "'Linux NFS Mailing List'" , "'linux-rdma'" , "'Tom Tucker'" References: <20140506174621.18208.24242.stgit@build.ogc.int> <20140506174632.18208.28160.stgit@build.ogc.int> <00f901cf6eeb$2ff1f630$8fd5e290$@opengridcomputing.com> <3DAF95F3-22D5-4FC5-8C98-5A440E54DC2F@gmail.com> <53737D15.6020902@opengridcomputing.com> <2AEECADA-4A40-4BF2-866E-7F178D016DDE@gmail.com> <009601cf6f9f$f47b2cb0$dd718610$@opengridcomputing.com> <639CE8CC-46CE-4EC9-A97B-2F146BA045C4@gmail.com> In-Reply-To: <639CE8CC-46CE-4EC9-A97B-2F146BA045C4@gmail.com> Subject: RE: [PATCH V2 RFC 2/3] svcrdma: Recvfrom changes Date: Wed, 14 May 2014 13:24:00 -0500 Message-ID: <009a01cf6fa1$ad1906b0$074b1410$@opengridcomputing.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Sender: linux-nfs-owner@vger.kernel.org List-ID: > >> > > > > So the code as it stands violates the RFC by sending 2 chunks? > > The Linux client is non-compliant because it sends two chunks. A compliant server ignores the > second chunk, so this is functionally harmless (but a waste of resources). > > The Linux server is non-compliant because it _requires_ the XDR pad chunk. A compliant client > (eg. Linux with pad optimization enabled) does not interoperate with it. > > > And if I change the server > > to only consume 1, then everything unaligned will break? > > If you change the server to consume only the first chunk, but do not also make it deal with XDR > padding as recommended in chapter 3 of RFC 5666, then WRITEs with a length that is not a > multiple of four will fail. SYMLINKs with a large payload will also have this problem. > Thanks Chuck for clarifying this! So I'm going to defer this issue and fix it with a subsequent patch to only process 1 chunk and handle pad correctly. Steve.