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=-8.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 2633FC8300A for ; Thu, 30 Apr 2020 08:59:02 +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 E5C5C20575 for ; Thu, 30 Apr 2020 08:59:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="GL5KPnlm" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E5C5C20575 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]:36980 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jU525-000166-5W for qemu-devel@archiver.kernel.org; Thu, 30 Apr 2020 04:59:01 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:44652) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jU51W-0000fX-7Z for qemu-devel@nongnu.org; Thu, 30 Apr 2020 04:58:26 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.90_1) (envelope-from ) id 1jU51V-0006i9-M6 for qemu-devel@nongnu.org; Thu, 30 Apr 2020 04:58:26 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:50961 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jU51V-0006i1-8Z for qemu-devel@nongnu.org; Thu, 30 Apr 2020 04:58:25 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1588237104; 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=YZWJbyskEh/t4LoyVabnWcxeWz+O95/+yCmDnV6MJtI=; b=GL5KPnlmls70nUyTzVtuaOYQiI2NsVKZ6HzzhIj+EOtwq0u1dAAHcyo9iOZTAoHWcRRrfr WgjhQ7fTUYwpJRhHcyIQDmSQ5Rng3IZBLt0vn+H6Lbz6lnPmzzCfsP6FvOv33heyCAn3GY otAhTzpyvOOa8Tu1nHeEUyqCSLcTBYo= 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-236-Xw65-uleP62JVs03yBntyw-1; Thu, 30 Apr 2020 04:58:22 -0400 X-MC-Unique: Xw65-uleP62JVs03yBntyw-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id BD603EC1A0 for ; Thu, 30 Apr 2020 08:58:21 +0000 (UTC) Received: from work-vm (ovpn-114-228.ams2.redhat.com [10.36.114.228]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 15CCA605DD; Thu, 30 Apr 2020 08:58:14 +0000 (UTC) Date: Thu, 30 Apr 2020 09:58:12 +0100 From: "Dr. David Alan Gilbert" To: Max Reitz Subject: Re: [PATCH] virtiofsd: Show submounts Message-ID: <20200430085812.GC2874@work-vm> References: <20200424133516.73077-1-mreitz@redhat.com> <20200427175902.GM2923@work-vm> <20200429145720.GA2835@work-vm> <8c73f374-fcc8-1684-b581-84a9ab501aa9@redhat.com> MIME-Version: 1.0 In-Reply-To: <8c73f374-fcc8-1684-b581-84a9ab501aa9@redhat.com> User-Agent: Mutt/1.13.4 (2020-02-15) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Received-SPF: pass client-ip=205.139.110.120; envelope-from=dgilbert@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/04/30 01:24:05 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] X-Received-From: 205.139.110.120 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: virtio-fs@redhat.com, Stefan Hajnoczi , qemu-devel@nongnu.org, vgoyal@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Max Reitz (mreitz@redhat.com) wrote: > On 29.04.20 16:57, Dr. David Alan Gilbert wrote: > > * Dr. David Alan Gilbert (dgilbert@redhat.com) wrote: > >> * Max Reitz (mreitz@redhat.com) wrote: > >>> Currently, setup_mounts() bind-mounts the shared directory without > >>> MS_REC. This makes all submounts disappear. > >>> > >>> Pass MS_REC so that the guest can see submounts again. > >> > >> Thanks! > >> > >>> Fixes: 3ca8a2b1c83eb185c232a4e87abbb65495263756 > >> > >> Should this actually be 5baa3b8e95064c2434bd9e2f312edd5e9ae275dc ? > >> > >>> Signed-off-by: Max Reitz > >>> --- > >>> tools/virtiofsd/passthrough_ll.c | 2 +- > >>> 1 file changed, 1 insertion(+), 1 deletion(-) > >>> > >>> diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passt= hrough_ll.c > >>> index 4c35c95b25..9d7f863e66 100644 > >>> --- a/tools/virtiofsd/passthrough_ll.c > >>> +++ b/tools/virtiofsd/passthrough_ll.c > >>> @@ -2643,7 +2643,7 @@ static void setup_mounts(const char *source) > >>> int oldroot; > >>> int newroot; > >>> =20 > >>> - if (mount(source, source, NULL, MS_BIND, NULL) < 0) { > >>> + if (mount(source, source, NULL, MS_BIND | MS_REC, NULL) < 0) { > >>> fuse_log(FUSE_LOG_ERR, "mount(%s, %s, MS_BIND): %m\n", sourc= e, source); > >>> exit(1); > >>> } > >> > >> Do we want MS_SLAVE to pick up future mounts that might happenf rom th= e > >> host? > >> What's the interaction between this and the MS_REC|MS_SLAVE that we ha= ve > >> a few lines above for / ? > >=20 > > Just to confirm something from vgoyal, and what had confused me about > > why we hadn't spotted this earlier. > >=20 > > Even without this patch, the SLAVE stuff worked so if you start the > > daemon and *then* mount under the shared directory, the guest sees it > > with or without this patch. >=20 > Hm, I don=E2=80=99t. Do you really? Yes! With your patch reverted: Start virtiofsd, mount in the guest: host: # ./virtiofsd --socket-path=3D/tmp/vhostqemu -o source=3D/home/dgilbert/vir= tio-fs/fs -o log_level=3Dwarn -o no_writeback guest: # mount -t virtiofs myfs /sysroot host: # findmnt -o +PROPAGATION -N 6100 TARGET SOURCE = FSTYPE OPTIONS PROPAGA= TION / /dev/mapper/fedora_dgilbert--t580-root[/home/dgilbert/virtio-fs/fs] = xfs rw,relatime,seclabel,attr2,inode64,logbufs=3D8,logbsize=3D32k,no pri= vate,slave # mount -t tmpfs /dev/null /home/dgilbert/virtio-fs/fs/tmp # findmnt -o +PROPAGATION -N 6100 TARGET SOURCE = FSTYPE OPTIONS PROPAGA= TION / /dev/mapper/fedora_dgilbert--t580-root[/home/dgilbert/virtio-fs/fs] = xfs rw,relatime,seclabel,attr2,inode64,logbufs=3D8,logbsize=3D32k,no pri= vate,slave =E2=94=94=E2=94=80/tmp /dev/null = tmpfs rw,relatime,seclabel = private,slave # touch /home/dgilbert/virtio-fs/fs/tmp/hello guest: # ls -l /sysroot/tmp total 0 -rw-r--r-- 1 root root 0 Apr 30 08:50 hello Maybe this is related to what Vivek said about default behaviours on systemd's, what does: # findmnt -o +PROPAGATION TARGET SOURCE FSTYPE OPTIONS = PROPAGATION / /dev/mapper/fedora_dgilbert--t580-root =E2=94=82 xfs rw,relatime,seclabel,attr2,inod= e64,logbufs=3D8,logbsize=3D32k,noquota shared say for your source=3D directory? Dave > Max >=20 -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK