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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,UNPARSEABLE_RELAY autolearn=ham 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 D16A0C282C2 for ; Wed, 13 Feb 2019 08:41:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AB0CC222BE for ; Wed, 13 Feb 2019 08:41:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390761AbfBMIlO (ORCPT ); Wed, 13 Feb 2019 03:41:14 -0500 Received: from out4437.biz.mail.alibaba.com ([47.88.44.37]:3007 "EHLO out4437.biz.mail.alibaba.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390759AbfBMIlO (ORCPT ); Wed, 13 Feb 2019 03:41:14 -0500 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R111e4;CH=green;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e07417;MF=wuyihao@linux.alibaba.com;NM=1;PH=DS;RN=3;SR=0;TI=SMTPD_---0TJzYfc5_1550047271; Received: from ali-186590dcce93-2.local(mailfrom:wuyihao@linux.alibaba.com fp:SMTPD_---0TJzYfc5_1550047271) by smtp.aliyun-inc.com(127.0.0.1); Wed, 13 Feb 2019 16:41:12 +0800 To: linux-nfs@vger.kernel.org Cc: jlayton@redhat.com From: Yihao Wu Subject: Why doesn't NFSv3 implement LOOKUPP? Message-ID: <3dc67361-9c2f-d183-09e5-0a4d5c48d0f7@linux.alibaba.com> Date: Wed, 13 Feb 2019 16:41:12 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:60.0) Gecko/20100101 Thunderbird/60.5.0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org Hi all, When looking into "Failures: generic/467" given by xfstests, I found that NFSv3 didn't implement LOOKUPP. I know that this might be by design. But LOOKUPP was meant to replace ".." in NFSv3, right? xfstests's generic/467 test case performs the following sequence of operations. name_to_handle -> drop_caches -> open_by_handle Dentry becomes disconnected due to drop_caches. NFSv3 doesn't support LOOKUPP. So when it performs open_by_handle to an directory, this test case fails. I did some small experiment by implementing LOOKUPP for NFSv3. The way I tried is to merely pass ".." to nfs3_proc_lookup. And it seems to work. At least it's a workaround for xfstests. I'm curious whether this sort of simulation of LOOKUPP will work or make sense. Thanks, Yihao Wu