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=-0.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 627A3C433DF for ; Wed, 27 May 2020 06:20:16 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3748520787 for ; Wed, 27 May 2020 06:20:16 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3748520787 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=bugs.launchpad.net Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:55832 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jdpQF-0002v5-E2 for qemu-devel@archiver.kernel.org; Wed, 27 May 2020 02:20:15 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:55628) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jdpPh-0002VK-HN for qemu-devel@nongnu.org; Wed, 27 May 2020 02:19:41 -0400 Received: from indium.canonical.com ([91.189.90.7]:36576) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1jdpPg-0005d0-2c for qemu-devel@nongnu.org; Wed, 27 May 2020 02:19:41 -0400 Received: from loganberry.canonical.com ([91.189.90.37]) by indium.canonical.com with esmtp (Exim 4.86_2 #2 (Debian)) id 1jdpPd-0005lz-TU for ; Wed, 27 May 2020 06:19:37 +0000 Received: from loganberry.canonical.com (localhost [127.0.0.1]) by loganberry.canonical.com (Postfix) with ESMTP id CB3412E8087 for ; Wed, 27 May 2020 06:19:37 +0000 (UTC) MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Date: Wed, 27 May 2020 06:03:53 -0000 From: Greg Kurz <1336794@bugs.launchpad.net> To: qemu-devel@nongnu.org X-Launchpad-Notification-Type: bug X-Launchpad-Bug: product=qemu; status=Confirmed; importance=Undecided; assignee=None; X-Launchpad-Bug: distribution=ubuntu; sourcepackage=None; component=None; status=Confirmed; importance=Undecided; assignee=None; X-Launchpad-Bug-Information-Type: Public X-Launchpad-Bug-Private: no X-Launchpad-Bug-Security-Vulnerability: no X-Launchpad-Bug-Commenters: agretha crobinso ericvh gkurz infinoid janitor l-admin-o maxim-kuvyrkov X-Launchpad-Bug-Reporter: Cole Robinson (crobinso) X-Launchpad-Bug-Modifier: Greg Kurz (gkurz) References: <20140702135258.23882.15100.malonedeb@soybean.canonical.com> Message-Id: <159055943336.806.7379057394662646136.malone@chaenomeles.canonical.com> Subject: [Bug 1336794] Re: 9pfs does not honor open file handles on unlinked files X-Launchpad-Message-Rationale: Subscriber (QEMU) @qemu-devel-ml X-Launchpad-Message-For: qemu-devel-ml Precedence: bulk X-Generated-By: Launchpad (canonical.com); Revision="1f7bc749b40714a4cc10f5e4d787118a78037035"; Instance="production-secrets-lazr.conf" X-Launchpad-Hash: a4b391a2f278390a1fc11040096240214498ea60 Received-SPF: none client-ip=91.189.90.7; envelope-from=bounces@canonical.com; helo=indium.canonical.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/27 01:00:55 X-ACL-Warn: Detected OS = Linux 3.11 and newer [fuzzy] X-Spam_score_int: -65 X-Spam_score: -6.6 X-Spam_bar: ------ X-Spam_report: (-6.6 / 5.0 requ) BAYES_00=-1.9, HEADER_FROM_DIFFERENT_DOMAINS=0.249, RCVD_IN_DNSWL_HI=-5, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, URIBL_BLOCKED=0.001 autolearn=_AUTOLEARN X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Bug 1336794 <1336794@bugs.launchpad.net> Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" For the records. QEMU patches: https://lists.nongnu.org/archive/html/qemu-devel/2016-06/msg07586.html Linux patches: https://sourceforge.net/p/v9fs/mailman/message/35175775/ -- = You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1336794 Title: 9pfs does not honor open file handles on unlinked files Status in QEMU: Confirmed Status in Ubuntu: Confirmed Bug description: This was originally filed over here: https://bugzilla.redhat.com/show_bug.cgi?id=3D1114221 The open-unlink-fstat idiom used in some places to create an anonymous private temporary file does not work in a QEMU guest over a virtio-9p filesystem. Version-Release number of selected component (if applicable): qemu-kvm-1.6.2-6.fc20.x86_64 qemu-system-x86-1.6.2-6.fc20.x86_64 (those are fedora RPMs) How reproducible: Always. See this example C program: https://bugzilla.redhat.com/attachment.cgi?id=3D913069 Steps to Reproduce: 1. Export a filesystem with virt-manager for the guest. (type: mount, driver: default, mode: passthrough) 2. Start guest and mount that filesystem (mount -t 9p -o trans=3Dvirtio,version=3D9p2000.L ...) 3. Run a program that uses open-unlink-fstat (in my case it was trying to compile Perl 5.20) Actual results: fstat fails: open("/home/tst/filename", O_RDWR|O_CREAT|O_EXCL, 0600) =3D 3 unlink("/home/tst/filename") =3D 0 fstat(3, 0x23aa1a8) =3D -1 ENOENT (No such file or di= rectory) close(3) Expected results: open("/home/tst/filename", O_RDWR|O_CREAT|O_EXCL, 0600) =3D 3 unlink("/home/tst/filename") =3D 0 fstat(3, {st_mode=3DS_IFREG|0600, st_size=3D0, ...}) =3D 0 fcntl(3, F_SETFD, FD_CLOEXEC) =3D 0 close(3) = Additional info: There was a patch put into the kernel back in '07 to handle this very problem for other filesystems; maybe its helpful: http://lwn.net/Articles/251228/ There is also a thread on LKML from last December specifically about this very problem: https://lkml.org/lkml/2013/12/31/163 There was a discussion on the QEMU list back in '11 that doesn't seem to have come to a conclusion, but did provide the test program that i've attached to this report: http://marc.info/?l=3Dqemu-devel&m=3D130443605720648&w=3D2 To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1336794/+subscriptions