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=-7.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_PASS,URIBL_BLOCKED, USER_AGENT_MUTT 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 E12A0C282CA for ; Tue, 12 Feb 2019 18:57:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BB158222C0 for ; Tue, 12 Feb 2019 18:57:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731263AbfBLS5a (ORCPT ); Tue, 12 Feb 2019 13:57:30 -0500 Received: from mx1.redhat.com ([209.132.183.28]:45308 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729371AbfBLS53 (ORCPT ); Tue, 12 Feb 2019 13:57:29 -0500 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 7DE17369CA; Tue, 12 Feb 2019 18:57:29 +0000 (UTC) Received: from horse.redhat.com (unknown [10.18.25.156]) by smtp.corp.redhat.com (Postfix) with ESMTP id 919C3194A0; Tue, 12 Feb 2019 18:57:25 +0000 (UTC) Received: by horse.redhat.com (Postfix, from userid 10451) id 295CE220992; Tue, 12 Feb 2019 13:57:25 -0500 (EST) Date: Tue, 12 Feb 2019 13:57:25 -0500 From: Vivek Goyal To: "Aneesh Kumar K.V" Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, miklos@szeredi.hu, stefanha@redhat.com, dgilbert@redhat.com, sweil@redhat.com, swhiteho@redhat.com Subject: Re: [PATCH 00/52] [RFC] virtio-fs: shared file system for virtual machines Message-ID: <20190212185725.GD6273@redhat.com> References: <20181210171318.16998-1-vgoyal@redhat.com> <871s4dc85b.fsf@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <871s4dc85b.fsf@linux.ibm.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Tue, 12 Feb 2019 18:57:29 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Feb 12, 2019 at 09:26:48PM +0530, Aneesh Kumar K.V wrote: > Vivek Goyal writes: > > > Hi, > > > > Here are RFC patches for virtio-fs. Looking for feedback on this approach. > > > > These patches should apply on top of 4.20-rc5. We have also put code for > > various components here. > > > > https://gitlab.com/virtio-fs > > > > Problem Description > > =================== > > We want to be able to take a directory tree on the host and share it with > > guest[s]. Our goal is to be able to do it in a fast, consistent and secure > > manner. Our primary use case is kata containers, but it should be usable in > > other scenarios as well. > > > > Containers may rely on local file system semantics for shared volumes, > > read-write mounts that multiple containers access simultaneously. File > > system changes must be visible to other containers with the same consistency > > expected of a local file system, including mmap MAP_SHARED. > > > > Existing Solutions > > ================== > > We looked at existing solutions and virtio-9p already provides basic shared > > file system functionality although does not offer local file system semantics, > > causing some workloads and test suites to fail. > > Can you elaborate on this? Is this with 9p2000.L ? We did quiet a lot of > work to make sure posix test suite pass on 9p file system. Also > was the mount option with cache=loose? Hi Aneesh, Yes this is with 9p2000.L and cache=loose. I used following mount option. mount -t 9p -o trans=virtio hostShared /mnt/virtio-9p/ -oversion=9p2000.L,posixacl,cache=loose We noticed primarily two issues. - Ran pjdfstests and a lot of them are failing. I think even kata container folks also experienced pjdfstests failures. I have never looked into details of why it is failing. - We thought mmap(MAP_SHARED) will not work with virtio-9p when two clients are running in two different VMs and mapped same file with MAP_SHARED. Having said that, biggest concern with virtio-9p seems to be performance. We are looking for ways to improve performance with virtio-fs. Hoping DAX can provide faster data access and fuse protocol itself seems to be faster (in primilinary testing results). Thanks Vivek