From patchwork Wed Mar 25 09:36:08 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wen Congyang X-Patchwork-Id: 454336 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 91B83140077 for ; Wed, 25 Mar 2015 20:41:26 +1100 (AEDT) Received: from localhost ([::1]:37134 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YahoS-0002Jc-K0 for incoming@patchwork.ozlabs.org; Wed, 25 Mar 2015 05:41:24 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40553) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Yahgt-0006DD-L2 for qemu-devel@nongnu.org; Wed, 25 Mar 2015 05:33:39 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Yahgp-0007uN-ET for qemu-devel@nongnu.org; Wed, 25 Mar 2015 05:33:35 -0400 Received: from [59.151.112.132] (port=1570 helo=heian.cn.fujitsu.com) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Yahgp-0007tv-2g; Wed, 25 Mar 2015 05:33:31 -0400 X-IronPort-AV: E=Sophos;i="5.04,848,1406563200"; d="scan'208";a="89293797" Received: from unknown (HELO edo.cn.fujitsu.com) ([10.167.33.5]) by heian.cn.fujitsu.com with ESMTP; 25 Mar 2015 17:29:45 +0800 Received: from G08CNEXCHPEKD02.g08.fujitsu.local (localhost.localdomain [127.0.0.1]) by edo.cn.fujitsu.com (8.14.3/8.13.1) with ESMTP id t2P9WRdj015810; Wed, 25 Mar 2015 17:32:27 +0800 Received: from G08FNSTD140052.g08.fujitsu.local (10.167.226.52) by G08CNEXCHPEKD02.g08.fujitsu.local (10.167.33.89) with Microsoft SMTP Server (TLS) id 14.3.181.6; Wed, 25 Mar 2015 17:33:32 +0800 From: Wen Congyang To: qemu devel , Fam Zheng , Max Reitz , Paolo Bonzini Date: Wed, 25 Mar 2015 17:36:08 +0800 Message-ID: <1427276174-9130-8-git-send-email-wency@cn.fujitsu.com> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1427276174-9130-1-git-send-email-wency@cn.fujitsu.com> References: <1427276174-9130-1-git-send-email-wency@cn.fujitsu.com> MIME-Version: 1.0 X-Originating-IP: [10.167.226.52] X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 59.151.112.132 Cc: Kevin Wolf , qemu block , Lai Jiangshan , Jiang Yunhong , Dong Eddie , "Dr. David Alan Gilbert" , Gonglei , Stefan Hajnoczi , Yang Hongyang , zhanghailiang Subject: [Qemu-devel] [RFC PATCH COLO v2 07/13] allow writing to the backing file 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 Signed-off-by: Wen Congyang Signed-off-by: zhanghailiang Signed-off-by: Gonglei --- block.c | 31 ++++++++++++++++++++++++++++++- 1 file changed, 30 insertions(+), 1 deletion(-) diff --git a/block.c b/block.c index 0ff5cf8..b4d629e 100644 --- a/block.c +++ b/block.c @@ -1247,6 +1247,20 @@ out: bdrv_refresh_limits(bs, NULL); } +#define ALLOW_WRITE_BACKING_FILE "allow-write-backing-file" +static QemuOptsList backing_file_opts = { + .name = "backing_file", + .head = QTAILQ_HEAD_INITIALIZER(backing_file_opts.head), + .desc = { + { + .name = ALLOW_WRITE_BACKING_FILE, + .type = QEMU_OPT_BOOL, + .help = "allow write to backing file", + }, + { /* end of list */ } + }, +}; + /* * Opens the backing file for a BlockDriverState if not yet open * @@ -1261,6 +1275,8 @@ int bdrv_open_backing_file(BlockDriverState *bs, QDict *options, Error **errp) int ret = 0; BlockDriverState *backing_hd; Error *local_err = NULL; + QemuOpts *opts = NULL; + int flags; if (bs->backing_hd != NULL) { QDECREF(options); @@ -1273,6 +1289,19 @@ int bdrv_open_backing_file(BlockDriverState *bs, QDict *options, Error **errp) } bs->open_flags &= ~BDRV_O_NO_BACKING; + flags = bdrv_backing_flags(bs->open_flags); + + opts = qemu_opts_create(&backing_file_opts, NULL, 0, &error_abort); + qemu_opts_absorb_qdict(opts, options, &local_err); + if (local_err) { + ret = -EINVAL; + goto free_exit; + } + if (qemu_opt_get_bool(opts, ALLOW_WRITE_BACKING_FILE, false)) { + flags |= BDRV_O_RDWR; + } + qemu_opts_del(opts); + if (qdict_haskey(options, "file.filename")) { backing_filename[0] = '\0'; } else if (bs->backing_file[0] == '\0' && qdict_size(options) == 0) { @@ -1305,7 +1334,7 @@ int bdrv_open_backing_file(BlockDriverState *bs, QDict *options, Error **errp) assert(bs->backing_hd == NULL); ret = bdrv_open(&backing_hd, *backing_filename ? backing_filename : NULL, NULL, options, - bdrv_backing_flags(bs->open_flags), NULL, &local_err); + flags, NULL, &local_err); if (ret < 0) { bdrv_unref(backing_hd); backing_hd = NULL;