Return-Path: Received: from mail-io0-f178.google.com ([209.85.223.178]:34759 "EHLO mail-io0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752286AbcC3SjT (ORCPT ); Wed, 30 Mar 2016 14:39:19 -0400 Received: by mail-io0-f178.google.com with SMTP id e3so85803185ioa.1 for ; Wed, 30 Mar 2016 11:39:19 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <20160330174040.GA12525@fieldses.org> Date: Wed, 30 Mar 2016 14:39:18 -0400 Message-ID: Subject: Re: out of order v3 write replies and cache invalidation From: Olga Kornievskaia To: Trond Myklebust Cc: "J. Bruce Fields" , linux-nfs Content-Type: text/plain; charset=UTF-8 Sender: linux-nfs-owner@vger.kernel.org List-ID: On Wed, Mar 30, 2016 at 2:20 PM, Trond Myklebust wrote: > On Wed, Mar 30, 2016 at 1:40 PM, J. Bruce Fields wrote: >> If we assume no other writers until we close, couldn't you on close wait >> for all writes, send a final getattr for change attribute, and trust >> that? If the extra getattr's too much, then you'd need some algorithm >> like the above to determine which change attribute is the last. Or >> implement >> https://tools.ietf.org/html/draft-ietf-nfsv4-minorversion2-41#section-12.2.3 >> on client and server and just track the maximum returned value when the >> server returns something other than NFS4_CHANGE_TYPE_IS_UNDEFINED. >> > > The correct tool to use for resolving these caching issues is > ultimately a write delegation. > > You can also eliminate a lot of invalidations if you know that the > server implements change_attr_type == > NFS4_CHANGE_TYPE_IS_VERSION_COUNTER or > NFS4_CHANGE_TYPE_IS_VERSION_COUNTER_NOPNFS, since that allows you to > predict what the attribute should be after a change. Thanks for all the info. But let me highlight that I was asking about v3. I don't see that the code has issues with cache invalidation for nfsv4 when receiving out-of-order RPCs. I am not sure if it's worth implementing something that Bruce suggests. I just wanted to make sure that what i'm seeing is "expected" behavior (caz it's v3) and not a bug.