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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,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 CA983C433E0 for ; Sat, 20 Feb 2021 20:34:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A7794601FB for ; Sat, 20 Feb 2021 20:34:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229905AbhBTUea (ORCPT ); Sat, 20 Feb 2021 15:34:30 -0500 Received: from ivanoab7.miniserver.com ([37.128.132.42]:45452 "EHLO www.kot-begemot.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229817AbhBTUe0 (ORCPT ); Sat, 20 Feb 2021 15:34:26 -0500 X-Greylist: delayed 1192 seconds by postgrey-1.27 at vger.kernel.org; Sat, 20 Feb 2021 15:34:25 EST Received: from tun252.jain.kot-begemot.co.uk ([192.168.18.6] helo=jain.kot-begemot.co.uk) by www.kot-begemot.co.uk with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1lDYdP-0001Ob-Ez; Sat, 20 Feb 2021 20:13:47 +0000 Received: from madding.kot-begemot.co.uk ([192.168.3.98]) by jain.kot-begemot.co.uk with esmtps (TLS1.3:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.92) (envelope-from ) id 1lDYdN-0007Q5-1O; Sat, 20 Feb 2021 20:13:47 +0000 Subject: Re: NFS Caching broken in 4.19.37 To: Salvatore Bonaccorso Cc: Linux Kernel Mailing List , 940821@bugs.debian.org, linux-nfs@vger.kernel.org, bfields@fieldses.org, chuck.lever@oracle.com References: <5022bdc4-9f3e-9756-cbca-ada37f88ecc7@cambridgegreys.com> From: Anton Ivanov Organization: Cambridge Greys Message-ID: Date: Sat, 20 Feb 2021 20:13:44 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Clacks-Overhead: GNU Terry Pratchett Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 20/02/2021 20:04, Salvatore Bonaccorso wrote: > Hi, > > On Mon, Jul 08, 2019 at 07:19:54PM +0100, Anton Ivanov wrote: >> Hi list, >> >> NFS caching appears broken in 4.19.37. >> >> The more cores/threads the easier to reproduce. Tested with identical >> results on Ryzen 1600 and 1600X. >> >> 1. Mount an openwrt build tree over NFS v4 >> 2. Run make -j `cat /proc/cpuinfo | grep vendor | wc -l` ; make clean in a >> loop >> 3. Result after 3-4 iterations: >> >> State on the client >> >> ls -laF /var/autofs/local/src/openwrt/build_dir/target-mips_24kc_musl/linux-ar71xx_tiny/linux-4.14.125/arch/mips/include/generated/uapi/asm >> >> total 8 >> drwxr-xr-x 2 anivanov anivanov 4096 Jul 8 11:40 ./ >> drwxr-xr-x 3 anivanov anivanov 4096 Jul 8 11:40 ../ >> >> State as seen on the server (mounted via nfs from localhost): >> >> ls -laF /var/autofs/local/src/openwrt/build_dir/target-mips_24kc_musl/linux-ar71xx_tiny/linux-4.14.125/arch/mips/include/generated/uapi/asm >> total 12 >> drwxr-xr-x 2 anivanov anivanov 4096 Jul 8 11:40 ./ >> drwxr-xr-x 3 anivanov anivanov 4096 Jul 8 11:40 ../ >> -rw-r--r-- 1 anivanov anivanov 32 Jul 8 11:40 ipcbuf.h >> >> Actual state on the filesystem: >> >> ls -laF /exports/work/src/openwrt/build_dir/target-mips_24kc_musl/linux-ar71xx_tiny/linux-4.14.125/arch/mips/include/generated/uapi/asm >> total 12 >> drwxr-xr-x 2 anivanov anivanov 4096 Jul 8 11:40 ./ >> drwxr-xr-x 3 anivanov anivanov 4096 Jul 8 11:40 ../ >> -rw-r--r-- 1 anivanov anivanov 32 Jul 8 11:40 ipcbuf.h >> >> So the client has quite clearly lost the plot. Telling it to drop caches and >> re-reading the directory shows the file present. >> >> It is possible to reproduce this using a linux kernel tree too, just takes >> much more iterations - 10+ at least. >> >> Both client and server run 4.19.37 from Debian buster. This is filed as >> debian bug 931500. I originally thought it to be autofs related, but IMHO it >> is actually something fundamentally broken in nfs caching resulting in cache >> corruption. > According to the reporter downstream in Debian, at > https://bugs.debian.org/940821#26 thi seem still reproducible with > more recent kernels than the initial reported. Is there anything Anton > can provide to try to track down the issue? > > Anton, can you reproduce with current stable series? 100% reproducible with any kernel from 4.9 to 5.4, stable or backports. It may exist in earlier versions, but I do not have a machine with anything before 4.9 to test at present. From 1-2 make clean && make  cycles to one afternoon depending on the number of machine cores. More cores/threads the faster it does it. I tried playing with protocol minor versions, caching options, etc - it is still reproducible for any nfs4 settings as long as there is client side caching of metadata. A. > > Regards, > Salvatore > -- Anton R. Ivanov Cambridgegreys Limited. Registered in England. Company Number 10273661 https://www.cambridgegreys.com/