From patchwork Thu Apr 28 12:57:20 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Fam Zheng X-Patchwork-Id: 8969681 Return-Path: X-Original-To: patchwork-qemu-devel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id CFCF8BF29F for ; Thu, 28 Apr 2016 12:58:09 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 4759D202EC for ; Thu, 28 Apr 2016 12:58:09 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 48054202AE for ; Thu, 28 Apr 2016 12:58:08 +0000 (UTC) Received: from localhost ([::1]:48729 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1avlWB-0000cw-Nl for patchwork-qemu-devel@patchwork.kernel.org; Thu, 28 Apr 2016 08:58:07 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60472) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1avlVw-0000ST-In for qemu-devel@nongnu.org; Thu, 28 Apr 2016 08:57:55 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1avlVs-00005B-GV for qemu-devel@nongnu.org; Thu, 28 Apr 2016 08:57:52 -0400 Received: from mx1.redhat.com ([209.132.183.28]:60221) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1avlVq-0008Ui-IX; Thu, 28 Apr 2016 08:57:46 -0400 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 26C567F0B0; Thu, 28 Apr 2016 12:57:46 +0000 (UTC) Received: from lemon.redhat.com (vpn1-5-154.pek2.redhat.com [10.72.5.154]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u3SCvWN4001193; Thu, 28 Apr 2016 08:57:39 -0400 From: Fam Zheng To: qemu-devel@nongnu.org Date: Thu, 28 Apr 2016 20:57:20 +0800 Message-Id: <1461848266-32119-2-git-send-email-famz@redhat.com> In-Reply-To: <1461848266-32119-1-git-send-email-famz@redhat.com> References: <1461848266-32119-1-git-send-email-famz@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.24 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v3 01/27] block: Add BDRV_O_NO_LOCK X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , qemu-block@nongnu.org, Jeff Cody , Markus Armbruster , Max Reitz , stefanha@redhat.com, den@openvz.org, pbonzini@redhat.com, John Snow Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Later the block layer will automatically lock the images to avoid unexpected concurrent accesses to the same image, which will easily corrupt the metadata or user data, unless in some very special cases, like migration. The exceptional cases like shared storage migration and testing should set BDRV_O_NO_LOCK the flag indicating that the block layer should skip the automatic locking of the image, like the old behavior. Signed-off-by: Fam Zheng Reviewed-by: Denis V. Lunev --- include/block/block.h | 1 + 1 file changed, 1 insertion(+) diff --git a/include/block/block.h b/include/block/block.h index 3a73137..b803597 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -94,6 +94,7 @@ typedef struct HDGeometry { select an appropriate protocol driver, ignoring the format layer */ #define BDRV_O_NO_IO 0x10000 /* don't initialize for I/O */ +#define BDRV_O_NO_LOCK 0x20000 /* don't lock image file */ #define BDRV_O_CACHE_MASK (BDRV_O_NOCACHE | BDRV_O_NO_FLUSH)