From patchwork Tue Aug 13 15:11:02 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michael Roth X-Patchwork-Id: 266874 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (unknown [IPv6:2001:4830:134:3::12]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id C41C12C0131 for ; Wed, 14 Aug 2013 02:01:46 +1000 (EST) Received: from localhost ([::1]:60662 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V9H2W-0006Bh-5M for incoming@patchwork.ozlabs.org; Tue, 13 Aug 2013 12:01:44 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60574) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V9GH4-0005mZ-Aq for qemu-devel@nongnu.org; Tue, 13 Aug 2013 11:12:51 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1V9GGv-00045q-4S for qemu-devel@nongnu.org; Tue, 13 Aug 2013 11:12:42 -0400 Received: from mail-oa0-x22f.google.com ([2607:f8b0:4003:c02::22f]:46485) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V9GGv-00045i-0A; Tue, 13 Aug 2013 11:12:33 -0400 Received: by mail-oa0-f47.google.com with SMTP id g12so11371122oah.6 for ; Tue, 13 Aug 2013 08:12:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:from:to:cc:subject:date:message-id:in-reply-to:references; bh=ZpQ3ORNIHpe3UoatGMLM7b2wOpQ55qKqt4rxLUwU5h8=; b=x0z84kiOfzHmwuDXwem5sYq3Ivt5etfbPsUAIeWfN2BDrd0Z6ZdonZfyimwZeyB4kl /7b+4i3sD9ZYg27LZpueUv7kJDNuQR/gAldnYoYiT2zdb0NBBYO220Uc0h6ThS1a3+i6 M38q06hs60h0i+kKC8sg6JGfY8e5C3Q+CJScrD3S0mkeLRylUzWvGQ9BDiee1sVllcSn K3AnSIp2wf1kqtNwDDx7sTbuiyLIut3c4TGsAGVS7VKeG7LHPk5WdqlPZCRt3tVtE95N moYU5yu+8OL4UvHjCs/Bck1aJSejd7NIDptMFMV1StcYXYp2Yd9pNVLNDrWB5oHVXriy S21A== X-Received: by 10.60.94.39 with SMTP id cz7mr4745297oeb.17.1376406752582; Tue, 13 Aug 2013 08:12:32 -0700 (PDT) Received: from loki.austin.ibm.com ([32.97.110.51]) by mx.google.com with ESMTPSA id uz16sm12947878obc.5.2013.08.13.08.12.30 for (version=TLSv1.1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Tue, 13 Aug 2013 08:12:31 -0700 (PDT) From: Michael Roth To: qemu-devel@nongnu.org Date: Tue, 13 Aug 2013 10:11:02 -0500 Message-Id: <1376406680-16302-39-git-send-email-mdroth@linux.vnet.ibm.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1376406680-16302-1-git-send-email-mdroth@linux.vnet.ibm.com> References: <1376406680-16302-1-git-send-email-mdroth@linux.vnet.ibm.com> X-detected-operating-system: by eggs.gnu.org: Error: Malformed IPv6 address (bad octet value). X-Received-From: 2607:f8b0:4003:c02::22f Cc: aliguori@us.ibm.com, qemu-stable@nongnu.org Subject: [Qemu-devel] [PATCH 38/56] dataplane: refuse to start if device is already in use X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org From: Stefan Hajnoczi Dataplane must check whether a block device is in use before launching the dataplane thread. This is necessary since the thread does not synchronize with the main loop and I/O requests could cause corruption. One example is when a drive is added and a block job is started before hotplugging the virtio-blk-pci adapter. In this case we must not use dataplane mode. Cc: qemu-stable@nongnu.org Reviewed-by: Kevin Wolf Signed-off-by: Stefan Hajnoczi (cherry picked from commit b0f2027cde31c645524256763672e09eeb204a9a) Signed-off-by: Michael Roth --- hw/block/dataplane/virtio-blk.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c index 0356665..a58cc53 100644 --- a/hw/block/dataplane/virtio-blk.c +++ b/hw/block/dataplane/virtio-blk.c @@ -418,6 +418,14 @@ bool virtio_blk_data_plane_create(VirtIODevice *vdev, VirtIOBlkConf *blk, return false; } + /* If dataplane is (re-)enabled while the guest is running there could be + * block jobs that can conflict. + */ + if (bdrv_in_use(blk->conf.bs)) { + error_report("cannot start dataplane thread while device is in use"); + return false; + } + fd = raw_get_aio_fd(blk->conf.bs); if (fd < 0) { error_report("drive is incompatible with x-data-plane, "