From patchwork Wed Sep 9 18:40:25 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Max Reitz X-Patchwork-Id: 274114 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=-9.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS 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 D50CCC43461 for ; Wed, 9 Sep 2020 18:44:12 +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 4C2832080C for ; Wed, 9 Sep 2020 18:44:12 +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="bVJxIGa/" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4C2832080C 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]:55014 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kG54l-0001QZ-Bq for qemu-devel@archiver.kernel.org; Wed, 09 Sep 2020 14:44:11 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:56590) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kG51r-0005yw-0n for qemu-devel@nongnu.org; Wed, 09 Sep 2020 14:41:11 -0400 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:38813 helo=us-smtp-delivery-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 1kG51p-0007SL-F5 for qemu-devel@nongnu.org; Wed, 09 Sep 2020 14:41:10 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1599676868; 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=nh0FPSe4hR16BIoT/N4xYTXt5vkDFlUFUIGOhNvTSeI=; b=bVJxIGa/7KsWqzYC62toP4Fsw+3JH84DMbhflW/KbTRsOKiHQ4oS6V2GT+twXeAoODDFcV iZgbzAr3GIvPop8H5/FGXrdsXVSXrOQ4z4Vfa6yW1Utu0s7OW7qJNDBjXHRca7m5suCU/H M2DnnuOZTiE26hUaWS0YpEzImtMZkjE= 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-125-cn6qZ8zrMl6JqWeBZOb9_Q-1; Wed, 09 Sep 2020 14:41:06 -0400 X-MC-Unique: cn6qZ8zrMl6JqWeBZOb9_Q-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id E94FC80EF8A for ; Wed, 9 Sep 2020 18:41:05 +0000 (UTC) Received: from localhost (ovpn-113-94.ams2.redhat.com [10.36.113.94]) by smtp.corp.redhat.com (Postfix) with ESMTPS id CC2A860BEC; Wed, 9 Sep 2020 18:40:59 +0000 (UTC) From: Max Reitz To: qemu-devel@nongnu.org Subject: [PATCH 5/8] virtiofsd: Store every lo_inode's parent_dev Date: Wed, 9 Sep 2020 20:40:25 +0200 Message-Id: <20200909184028.262297-6-mreitz@redhat.com> In-Reply-To: <20200909184028.262297-1-mreitz@redhat.com> References: <20200909184028.262297-1-mreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=mreitz@redhat.com X-Mimecast-Spam-Score: 0.002 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=207.211.31.81; envelope-from=mreitz@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/09/09 02:43:02 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_H2=-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, Miklos Szeredi , "Dr . David Alan Gilbert" , Stefan Hajnoczi , Max Reitz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" 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 --- 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 784330e0e4..2c48c03b4c 100644 --- a/tools/virtiofsd/passthrough_ll.c +++ b/tools/virtiofsd/passthrough_ll.c @@ -124,6 +124,14 @@ 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 { @@ -821,6 +829,7 @@ 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); @@ -1047,6 +1056,14 @@ 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);