From patchwork Fri Jun 3 08:48:55 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Fam Zheng X-Patchwork-Id: 9152301 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 4F45E6072B for ; Fri, 3 Jun 2016 09:03:04 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 438E626D19 for ; Fri, 3 Jun 2016 09:03:04 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 382FC28309; Fri, 3 Jun 2016 09:03:04 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 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.wl.linuxfoundation.org (Postfix) with ESMTPS id D96D526D19 for ; Fri, 3 Jun 2016 09:03:03 +0000 (UTC) Received: from localhost ([::1]:53472 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b8l0Q-0002JS-U4 for patchwork-qemu-devel@patchwork.kernel.org; Fri, 03 Jun 2016 05:03:03 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54909) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b8knd-0006je-Jd for qemu-devel@nongnu.org; Fri, 03 Jun 2016 04:49:55 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1b8knX-0001po-Uh for qemu-devel@nongnu.org; Fri, 03 Jun 2016 04:49:48 -0400 Received: from mx1.redhat.com ([209.132.183.28]:58114) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b8knK-0001m5-AN; Fri, 03 Jun 2016 04:49:30 -0400 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (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 C2259C049E1D; Fri, 3 Jun 2016 08:49:29 +0000 (UTC) Received: from ad.usersys.redhat.com (dhcp-15-133.nay.redhat.com [10.66.15.133]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u538nKXl023508; Fri, 3 Jun 2016 04:49:24 -0400 From: Fam Zheng To: qemu-devel@nongnu.org Date: Fri, 3 Jun 2016 16:48:55 +0800 Message-Id: <1464943756-14143-2-git-send-email-famz@redhat.com> In-Reply-To: <1464943756-14143-1-git-send-email-famz@redhat.com> References: <1464943756-14143-1-git-send-email-famz@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Fri, 03 Jun 2016 08:49:29 +0000 (UTC) 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 v6 01/22] block: Add flag bits for image locking 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, rjones@redhat.com, John Snow , Jeff Cody , Markus Armbruster , Max Reitz , stefanha@redhat.com, den@openvz.org, pbonzini@redhat.com Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" 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_SHARED_LOCK or BDRV_O_NO_LOCK to advise an appropriate locking mode. Signed-off-by: Fam Zheng Reviewed-by: Max Reitz --- include/block/block.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/include/block/block.h b/include/block/block.h index 70ea299..02b598b 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -94,6 +94,8 @@ 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_SHARED_LOCK 0x40000 /* lock the image file in shared mode */ #define BDRV_O_CACHE_MASK (BDRV_O_NOCACHE | BDRV_O_NO_FLUSH)