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=-2.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 A1F7BC47247 for ; Tue, 5 May 2020 17:48:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6E020206B9 for ; Tue, 5 May 2020 17:48:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (3072-bit key) header.d=samba.org header.i=@samba.org header.b="mjP7Fwh5" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728804AbgEERsp (ORCPT ); Tue, 5 May 2020 13:48:45 -0400 Received: from hr2.samba.org ([144.76.82.148]:56548 "EHLO hr2.samba.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729315AbgEERso (ORCPT ); Tue, 5 May 2020 13:48:44 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=samba.org; s=42; h=Message-ID:Cc:To:From:Date; bh=M0P66gTN407+d6oKcb86AA0qCqZU3InlzDHRpphxKbY=; b=mjP7Fwh5fNC3dPOYP2tWBalZ4g mQ4UytaBRDXIowy3L3+YDGzFs5x4f5TBxqfwXagb9Op3O7s63onU3kHCuore0zWKc+cBRPRdDF15Y bbyuwwfPyhptHWVGiagiefKHSt1AlHvRwWw1KQLvqyr1YyUoRFtXpYo4vPWF1IWW90GEF2WQ51MRC WV7N9/ufasUnuK2fuaLMI+4LPt/L/L7IUT4MOy4794r/ivzGKe8ADcsVFRD5bk9gNkwj+CoT8joAv E6AFcqIpo5jRf8JFl7igiLnCPOgJmwgS0mVI1jQiqBzhsLO3hvuvesxiCBEOgUGOEBDWe0/5Y+x6E f+2Hb8WDNPZeT1NO2egpMdkbrmPBcfcq/25pRZnxhXaD+7VJgx46ubPstCXMFXQU2PhVCzPKx9tmF ULG0oD1eEESLHkHobvU/UZhl/xfqIu4Cr4zNzIF2e8gyQW+D2J2oyr4GOrUCRhS1G9s//EmMp6bkI NqCSPXzYJLRL+Sspus/L2ss6; Received: from [127.0.0.2] (localhost [127.0.0.1]) by hr2.samba.org with esmtpsa (TLS1.3:ECDHE_RSA_CHACHA20_POLY1305:256) (Exim) id 1jW1gN-0005Qe-Oy; Tue, 05 May 2020 17:48:40 +0000 Date: Tue, 5 May 2020 10:48:32 -0700 From: Jeremy Allison To: Jens Axboe Cc: Stefan Metzmacher , io-uring , Samba Technical , jra@samba.org Subject: Re: Data Corruption bug with Samba's vfs_iouring and Linux 5.6.7/5.7rc3 Message-ID: <20200505174832.GC7920@jeremy-acer> Reply-To: Jeremy Allison References: <0009f6b7-9139-35c7-c0b1-b29df2a67f70@samba.org> <102c824b-b2f5-bbb1-02da-d2a78c3ff460@kernel.dk> <7ed7267d-a0ae-72ac-2106-2476773f544f@kernel.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: io-uring-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On Tue, May 05, 2020 at 11:39:14AM -0600, Jens Axboe wrote: > >=20 > > I'll try and see if I can get an arch binary build that has the > > vfs_io_uring module and reproduce. >=20 > Got that done, and I can now mount it on Linux. Been trying pretty > hard to trigger any corruptions on reads, but it works for me. Checked > that we see short reads, and we do, and that it handles it just fine. > So pretty blank right now on what this could be. >=20 > FWIW, I'm mounting on Linux as: >=20 > # mount -t cifs -o ro,guest //arch/data /smb The reporter claims this only happens with a Windows client, as the Linux and Samba libsmb clients don't pipeline the reads in the same way for multiple files the same way that Windows does. Here is the bug report with all the details I've managed to get out of the original reporter: https://bugzilla.samba.org/show_bug.cgi?id=3D14361 I also can't reproduce the data corruption, even =66rom a Windows client although I've only tried so far on my home Ubuntu 19.04 kernel 5.3.0-51-generic #44-Ubuntu SMP box. I tried running 2 powershell processes on the Windows client and doing a copy in both of them to ensure we are opening multiple files simultaneously and going through the io_uring module (which I saw happening by adding debug statements) but I never see corruption. I'm planning to try running against a Fedora32 VM next, as that's case the reporter claims will reproduce the issue. Thanks for helping me look at this ! Jeremy.