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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]:37854 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kZtbh-00067q-84 for qemu-devel@archiver.kernel.org; Tue, 03 Nov 2020 05:32:05 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:48840) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kZtZY-0004fv-0V for qemu-devel@nongnu.org; Tue, 03 Nov 2020 05:29:52 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:44836) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kZtZU-0002LD-6b for qemu-devel@nongnu.org; Tue, 03 Nov 2020 05:29:51 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1604399386; 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=63GzjYcexcJ6f4R/gzQDJePTgnKS5LFqiJk6U1Jm9hg=; b=Cd8KofbOf9UH/JdymoklLAkxxSL3fHo6fx+LLQGsI+1aC5ysEwC7gH6lzGGpTUveQDNcq8 14SUW9ZERyuqJyp30YmLcZLNcZcLqR5mmbrqo4bane+Y11zHP/0L3uUQsppHGe9wo1Efom r3ILXxZQYUysb6De+biyN9yqZXzuVGk= 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-40-_fZyrOm6OnCxEQxUpihLNw-1; Tue, 03 Nov 2020 05:29:44 -0500 X-MC-Unique: _fZyrOm6OnCxEQxUpihLNw-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id B434B6D271; Tue, 3 Nov 2020 10:29:43 +0000 (UTC) Received: from work-vm (ovpn-115-84.ams2.redhat.com [10.36.115.84]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D78B05C230; Tue, 3 Nov 2020 10:29:35 +0000 (UTC) Date: Tue, 3 Nov 2020 10:29:33 +0000 From: "Dr. David Alan Gilbert" To: Max Reitz Subject: Re: [PULL 10/12] virtiofsd: Announce sub-mount points Message-ID: <20201103102933.GC3566@work-vm> References: <20201102195657.219501-1-dgilbert@redhat.com> <20201102195657.219501-11-dgilbert@redhat.com> MIME-Version: 1.0 In-Reply-To: User-Agent: Mutt/1.14.6 (2020-07-11) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dgilbert@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=63.128.21.124; envelope-from=dgilbert@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/11/03 01:02:05 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] 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, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=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: quintela@redhat.com, qemu-devel@nongnu.org, peterx@redhat.com, zhangjiachen.jaycee@bytedance.com, stefanha@redhat.com, philmd@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Max Reitz (mreitz@redhat.com) wrote: > On 02.11.20 20:56, Dr. David Alan Gilbert (git) wrote: > > From: Max Reitz > > > > Whenever we encounter a directory with an st_dev or mount ID that > > differs from that of its parent, we set the FUSE_ATTR_SUBMOUNT flag so > > the guest can create a submount for it. > > > > We only need to do so in lo_do_lookup(). The following functions return > > a fuse_attr object: > > - lo_create(), though fuse_reply_create(): Calls lo_do_lookup(). > > - lo_lookup(), though fuse_reply_entry(): Calls lo_do_lookup(). > > - lo_mknod_symlink(), through fuse_reply_entry(): Calls lo_do_lookup(). > > - lo_link(), through fuse_reply_entry(): Creating a link cannot create a > > submount, so there is no need to check for it. > > - lo_getattr(), through fuse_reply_attr(): Announcing submounts when the > > node is first detected (at lookup) is sufficient. We do not need to > > return the submount attribute later. > > - lo_do_readdir(), through fuse_add_direntry_plus(): Calls > > lo_do_lookup(). > > > > Make announcing submounts optional, so submounts are only announced to > > the guest with the announce_submounts option. Some users may prefer the > > current behavior, so that the guest learns nothing about the host mount > > structure. > > > > (announce_submounts is force-disabled when the guest does not present > > the FUSE_SUBMOUNTS capability, or when there is no statx().) > > > > Signed-off-by: Max Reitz > > Reviewed-by: Stefan Hajnoczi > > Message-Id: <20201102161859.156603-6-mreitz@redhat.com> > > Signed-off-by: Dr. David Alan Gilbert > > --- > > tools/virtiofsd/helper.c | 1 + > > tools/virtiofsd/passthrough_ll.c | 22 ++++++++++++++++++++++ > > 2 files changed, 23 insertions(+) > > > diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c > [...] > > > index 34d107975f..ec1008bceb 100644 > > --- a/tools/virtiofsd/passthrough_ll.c > > +++ b/tools/virtiofsd/passthrough_ll.c > > [...] > > > @@ -601,6 +604,20 @@ static void lo_init(void *userdata, struct fuse_conn_info *conn) > > [...] > > > +#ifndef CONFIG_STATX > > + if (lo->announce_submounts) { > > + fuse_log(FUSE_LOG_WARNING, "lo_init: Cannot announce submounts, there " > > + "is no statx()\n"); > > + lo->announce_submounts = false; > > + } > > +#endif > > When reviewing this series, Miklos noted today that this warning is > wrong (we can still announce submounts even without statx()), and we > concluded that we should probably drop it and the > “lo->announce_submounts = false” assignment (i.e. this whole block). > > I don’t think that needs to stop this pull request, though, we can > easily fix it on top. That's OK, send me a follow up patch to fix the warning; that's a minor. Dave > Max -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK