From patchwork Fri Dec 15 08:04:45 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Fam Zheng X-Patchwork-Id: 10114177 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 542D060231 for ; Fri, 15 Dec 2017 08:06:04 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 469BB29F16 for ; Fri, 15 Dec 2017 08:06:04 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3B88929F1B; Fri, 15 Dec 2017 08:06:04 +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 B9C1A29F16 for ; Fri, 15 Dec 2017 08:06:03 +0000 (UTC) Received: from localhost ([::1]:45013 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ePl0M-000809-UX for patchwork-qemu-devel@patchwork.kernel.org; Fri, 15 Dec 2017 03:06:02 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59563) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ePkzN-0007Dv-6P for qemu-devel@nongnu.org; Fri, 15 Dec 2017 03:05:02 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ePkzJ-0001IN-EU for qemu-devel@nongnu.org; Fri, 15 Dec 2017 03:05:01 -0500 Received: from mx1.redhat.com ([209.132.183.28]:50442) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ePkzF-0001FK-BW; Fri, 15 Dec 2017 03:04:53 -0500 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 8F34BC0587D4; Fri, 15 Dec 2017 08:04:52 +0000 (UTC) Received: from lemon.redhat.com (ovpn-12-91.pek2.redhat.com [10.72.12.91]) by smtp.corp.redhat.com (Postfix) with ESMTP id F024F614D0; Fri, 15 Dec 2017 08:04:50 +0000 (UTC) From: Fam Zheng To: qemu-devel@nongnu.org Date: Fri, 15 Dec 2017 16:04:45 +0800 Message-Id: <20171215080446.10671-2-famz@redhat.com> In-Reply-To: <20171215080446.10671-1-famz@redhat.com> References: <20171215080446.10671-1-famz@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Fri, 15 Dec 2017 08:04:52 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH 1/2] block: Open backing image in force share mode for size probe 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, Max Reitz Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP Management tools create overlays of running guests with qemu-img: $ qemu-img create -b /image/in/use.qcow2 -f qcow2 /overlay/image.qcow2 but this doesn't work anymore due to image locking: qemu-img: /overlay/image.qcow2: Failed to get shared "write" lock Is another process using the image? Could not open backing image to determine size. Use the force share option to allow this use case again. Cc: qemu-stable@nongnu.org Signed-off-by: Fam Zheng --- block.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/block.c b/block.c index 9a1a0d1e73..f236431da1 100644 --- a/block.c +++ b/block.c @@ -4593,10 +4593,11 @@ void bdrv_img_create(const char *filename, const char *fmt, back_flags = flags; back_flags &= ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING); + backing_options = qdict_new(); if (backing_fmt) { - backing_options = qdict_new(); qdict_put_str(backing_options, "driver", backing_fmt); } + qdict_put_bool(backing_options, BDRV_OPT_FORCE_SHARE, true); bs = bdrv_open(full_backing, NULL, backing_options, back_flags, &local_err);