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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 64C46C433DB for ; Wed, 17 Mar 2021 11:51:46 +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 B089D64F2A for ; Wed, 17 Mar 2021 11:51:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B089D64F2A Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=crudebyte.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:51160 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lMUiG-0007xc-Ih for qemu-devel@archiver.kernel.org; Wed, 17 Mar 2021 07:51:44 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:51510) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lMUgg-0006dc-J1 for qemu-devel@nongnu.org; Wed, 17 Mar 2021 07:50:06 -0400 Received: from kylie.crudebyte.com ([5.189.157.229]:50587) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lMUgc-0008Ig-Qs for qemu-devel@nongnu.org; Wed, 17 Mar 2021 07:50:06 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=crudebyte.com; s=kylie; h=Content-Type:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Content-ID:Content-Description; bh=WEz1d/e2FD0Bb0jqfPmPixKcTTK0zElGy1qtD/uutw4=; b=e6VZHa0ehiWNW2azoEfh57Fe81 w6yfNMssKw9JSlLqXclxE7MyqDhVyzx+effkHOjH5VKSqSOgpfuQ4QrbvTYidGGa0QycvE2Vyt3px 7QD6Tc+H4jUVovMSFjI3fQIK4/Ag9zUgfksL2LcrMgVMU8iQLO1pwdR2HG/NTOGTSlsKPmtfEG14C y8DXZpa3eWLKj5AGh3QrbxiLAI61kwT1CCEVgUMU27EWTI07LdHiRG9pmIpmHK4IajXLWDtSnv4F4 UnJs8B82GxvoR89jJl7Gc9MTENOZZsFkzFqNtnJAOqqJwTZmT81gV0sOWJOIShgnDZryqAtZO+D4o I+RbA6Dx49JlFrOSlZt+eEwm3rNSGZOhSZCABiFkZ5FYb+/oQdE4CdK1tBDr4MYmKNzif9Srftxs0 +L8OB0RAuOcaPrcUNz3cNkbROR9qyp693T5xfXA0C85y81Hgn66FJ2f1bJQErOlmo7tsmtRIpNQpC LBARVO2qVjwxrNh+LzygwlwbWIiNRJDmojVvpLTKmn3Pp5V6hlG9UvzGijGSRrsrVZqpetfmAJXmi a8QHHAN4YRAzuom7qzQOIMgThHsfVgpznONXIA/2g+8NoUc9uVNw9s2qedFxhKYP1mCf+Mc7JxBga KCljkb/oKljv3bIMZKQlzWgMMO6mWz9vvSgHpOL9Y=; From: Christian Schoenebeck To: qemu-devel@nongnu.org Cc: Stefan Hajnoczi , Jiachen Zhang , "Daniel P. Berrange" , slp@redhat.com, "Michael S . Tsirkin" , "Dr . David Alan Gilbert" , virtio-fs@redhat.com, Xie Yongji , =?ISO-8859-1?Q?Marc=2DAndr=E9?= Lureau Subject: Re: [External] Re: [RFC PATCH 0/9] Support for Virtio-fs daemon crash reconnection Date: Wed, 17 Mar 2021 12:49:37 +0100 Message-ID: <1709993.NBFj2RoZ23@silver> In-Reply-To: References: <20201215162119.27360-1-zhangjiachen.jaycee@bytedance.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="iso-8859-1" Received-SPF: pass client-ip=5.189.157.229; envelope-from=qemu_oss@crudebyte.com; helo=kylie.crudebyte.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Mittwoch, 17. M=E4rz 2021 11:05:32 CET Stefan Hajnoczi wrote: > On Fri, Dec 18, 2020 at 05:39:34PM +0800, Jiachen Zhang wrote: > > Thanks for the suggestions. Actually, we choose to save all state > > information to QEMU because a virtiofsd has the same lifecycle as its > > QEMU master. However, saving things to a file do avoid communication wi= th > > QEMU, and we no longer need to increase the complexity of vhost-user > > protocol. The suggestion to save fds to the systemd is also very > > reasonable > > if we don't consider the lifecycle issues, we will try it. >=20 > Hi, > We recently discussed crash recovery in the virtio-fs bi-weekly call and > I read some of this email thread because it's a topic I'm interested in. I just had a quick fly over the patches so far. Shouldn't there be some kin= d=20 of constraint for an automatic reconnection feature after a crash to preven= t=20 this being exploited by ROP brute force attacks? E.g. adding some (maybe continuously increasing) delay and/or limiting the= =20 amount of reconnects within a certain time frame would come to my mind. Best regards, Christian Schoenebeck