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=-6.3 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,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 0A95FC433E0 for ; Mon, 21 Dec 2020 12:50:05 +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 59D71227BF for ; Mon, 21 Dec 2020 12:50:04 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 59D71227BF Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:44814 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1krKdX-0003V1-57 for qemu-devel@archiver.kernel.org; Mon, 21 Dec 2020 07:50:03 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:45134) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1krKcv-00033j-M0 for qemu-devel@nongnu.org; Mon, 21 Dec 2020 07:49:25 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:51100) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1krKct-0000YH-0V for qemu-devel@nongnu.org; Mon, 21 Dec 2020 07:49:25 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1608554962; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=5yCz1xk1G61tEQ0WOrnpa0N67Ud3Qjk8WX3/nKpYlCg=; b=GlmlmtM07HlbUmLu32//GKAjkugb8CNOX1J9ocslAy9QbKtpYBoH1EcjMzYsBd1Kr/7Szh cqjSBCX3EHMmC/ReqfqQ+a87DuS37nKmrOLhXJtGvWn48te1BzxMJYebZJ1HM9MY3R/gaj HJP9tGDMR6DZeH1dGG/3HFjuHpAoPtk= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-568-bc7xoo4VNjiVSkSxMtUi1Q-1; Mon, 21 Dec 2020 07:49:20 -0500 X-MC-Unique: bc7xoo4VNjiVSkSxMtUi1Q-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9ED7D180A087 for ; Mon, 21 Dec 2020 12:49:19 +0000 (UTC) Received: from dresden.str.redhat.com (ovpn-114-3.ams2.redhat.com [10.36.114.3]) by smtp.corp.redhat.com (Postfix) with ESMTPS id F00CD5D6D1; Mon, 21 Dec 2020 12:49:09 +0000 (UTC) Subject: Re: virtiofsd: sshfs as submount? To: Laszlo Ersek , Miklos Szeredi References: <599fd4bd-2f62-1ce5-2b9c-0512ee7ead6e@redhat.com> <0208dde6-df57-c27a-418f-57cb3c0173f2@redhat.com> From: Max Reitz Message-ID: <06de2310-e566-61a7-9ae8-679e9fefabc3@redhat.com> Date: Mon, 21 Dec 2020 13:49:07 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.5.0 MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=mreitz@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=63.128.21.124; envelope-from=mreitz@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -32 X-Spam_score: -3.3 X-Spam_bar: --- X-Spam_report: (-3.3 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-1.233, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, 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: , Cc: =?UTF-8?Q?Daniel_P=2e_Berrang=c3=a9?= , qemu devel list , "Dr. David Alan Gilbert" , virtio-fs@redhat.com, Stefan Hajnoczi , Vivek Goyal Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 21.12.20 13:45, Laszlo Ersek wrote: > On 12/21/20 13:06, Max Reitz wrote: > >> I can share sshfs through sshfs, so it must be something virtiofs-specific. > > Your insight proved crucial to solving the riddle. > > Chaining sshfs with sshfs made me think that you must have used a normal > (non-root) user account on the first remote computer (where you ran the > 2nd sshfs command). > > And that reminded me of the "allow_root" option which I seemed to have > read somewhere around the FUSE manuals. Oh, that makes sense. Right. > So indeed I set up another sshfs mount on my laptop, with my normal UID, > and tried to access the mount point from a plain root shell (with > virtiofsd completely out of the picture) -- it failed with "Permission > denied". :) It's apparently intentional on sshfs's / FUSE's part, to > protect the local root user from "remote nastiness injection". > > Then I re-did the sshfs mount, but with "-o allow_root" this time. The > plain root shell can now access the mount point. Indeed, that works better. > ... So can virtiofsd :) It's *amazing* to see remote files in the UEFI > shell. I never thought "filesystem as a service" could feel this empowering. > > Thanks, Max! Er, *cough*, my pleasure! O:) Max