From patchwork Mon Oct 26 18:43:28 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Dr. David Alan Gilbert" X-Patchwork-Id: 11858309 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 426A0697 for ; Mon, 26 Oct 2020 18:54:48 +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 D2B6D2168B for ; Mon, 26 Oct 2020 18:54:47 +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="eKH+sEKu" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D2B6D2168B 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+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Received: from localhost ([::1]:49852 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kX7dm-0005d0-QP for patchwork-qemu-devel@patchwork.kernel.org; Mon, 26 Oct 2020 14:54:46 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:45942) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kX7Tb-0002cK-KM for qemu-devel@nongnu.org; Mon, 26 Oct 2020 14:44:15 -0400 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:50305) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kX7TZ-0003cP-R7 for qemu-devel@nongnu.org; Mon, 26 Oct 2020 14:44:15 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1603737852; 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=Oc+dmUX2To63s+lZkfkb1mzuLK1KZe6J4nW/upXzUv0=; b=eKH+sEKuIOwBc8ZOeXAJBI6l3khCj9NulmPKb4QfSFhjgIuLl+w2fnSdEqnHrAbor/kHin SZi4OIKiUQH5zLKPKVwces+hUBMFovXCv+Xb64033HPtf2P1nrHHiYGinMq4U35UvL7ET/ wN09kjLC50Xj18P9K80gNBMOVlYhPeY= 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-512-rsQDjw4vOfGYC0ZpcjAiUQ-1; Mon, 26 Oct 2020 14:44:10 -0400 X-MC-Unique: rsQDjw4vOfGYC0ZpcjAiUQ-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id CDFE7803F4F; Mon, 26 Oct 2020 18:44:09 +0000 (UTC) Received: from dgilbert-t580.localhost (ovpn-112-208.ams2.redhat.com [10.36.112.208]) by smtp.corp.redhat.com (Postfix) with ESMTP id 779C15D9CA; Mon, 26 Oct 2020 18:44:08 +0000 (UTC) From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org, stefanha@redhat.com, mreitz@redhat.com, misono.tomohiro@jp.fujitsu.com Subject: [PULL 13/16] virtiofsd: Store every lo_inode's parent_dev Date: Mon, 26 Oct 2020 18:43:28 +0000 Message-Id: <20201026184331.272953-14-dgilbert@redhat.com> In-Reply-To: <20201026184331.272953-1-dgilbert@redhat.com> References: <20201026184331.272953-1-dgilbert@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 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 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 = 2020/10/25 21:03:19 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: virtio-fs@redhat.com, vgoyal@Redhat.com Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" From: Max Reitz We want to detect mount points in the shared tree. We report them to the guest by setting the FUSE_ATTR_SUBMOUNT flag in fuse_attr.flags, but because the FUSE client will create a submount for every directory that has this flag set, we must do this only for the actual mount points. We can detect mount points by comparing a directory's st_dev with its parent's st_dev. To be able to do so, we need to store the parent's st_dev in the lo_inode object. Note that mount points need not necessarily be directories; a single file can be a mount point as well. However, for the sake of simplicity let us ignore any non-directory mount points for now. Signed-off-by: Max Reitz Message-Id: <20200909184028.262297-6-mreitz@redhat.com> Reviewed-by: Dr. David Alan Gilbert Signed-off-by: Dr. David Alan Gilbert --- tools/virtiofsd/passthrough_ll.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c index a0beb986f3..4188bf3ad2 100644 --- a/tools/virtiofsd/passthrough_ll.c +++ b/tools/virtiofsd/passthrough_ll.c @@ -125,6 +125,14 @@ struct lo_inode { GHashTable *posix_locks; /* protected by lo_inode->plock_mutex */ mode_t filetype; + + /* + * So we can detect crossmount roots + * (As such, this only needs to be valid for directories. Note + * that files can have multiple parents due to hard links, and so + * their parent_dev may fluctuate.) + */ + dev_t parent_dev; }; struct lo_cred { @@ -847,6 +855,7 @@ static int lo_do_lookup(fuse_req_t req, fuse_ino_t parent, const char *name, g_hash_table_insert(lo->inodes, &inode->key, inode); pthread_mutex_unlock(&lo->mutex); } + inode->parent_dev = dir->key.dev; e->ino = inode->fuse_ino; lo_inode_put(lo, &inode); lo_inode_put(lo, &dir); @@ -1073,6 +1082,14 @@ static void lo_link(fuse_req_t req, fuse_ino_t ino, fuse_ino_t parent, fuse_log(FUSE_LOG_DEBUG, " %lli/%s -> %lli\n", (unsigned long long)parent, name, (unsigned long long)e.ino); + /* + * No need to update inode->parent_dev, because + * (1) We cannot, the inode now has more than one parent, + * (2) Directories cannot have more than one parent, so link() + * does not work for them; but parent_dev only needs to be + * valid for directories. + */ + fuse_reply_entry(req, &e); lo_inode_put(lo, &parent_inode); lo_inode_put(lo, &inode);