From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56244) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YqeKm-00021r-6R for qemu-devel@nongnu.org; Fri, 08 May 2015 05:12:41 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YqeKh-0004T5-Qd for qemu-devel@nongnu.org; Fri, 08 May 2015 05:12:40 -0400 From: Wen Congyang Date: Fri, 8 May 2015 17:15:54 +0800 Message-ID: <1431076567-30371-3-git-send-email-wency@cn.fujitsu.com> In-Reply-To: <1431076567-30371-1-git-send-email-wency@cn.fujitsu.com> References: <1431076567-30371-1-git-send-email-wency@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain Subject: [Qemu-devel] [PATCH COLO v4 02/15] allow writing to the backing file List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu devel , Fam Zheng , Max Reitz , Paolo Bonzini Cc: Kevin Wolf , qemu block , Lai Jiangshan , Jiang Yunhong , Dong Eddie , "Dr. David Alan Gilbert" , Gonglei , Stefan Hajnoczi , Yang Hongyang , zhanghailiang 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 49d472f..8fa4f05 100644 --- a/block.c +++ b/block.c @@ -1051,6 +1051,20 @@ 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 * @@ -1065,6 +1079,8 @@ 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); @@ -1077,6 +1093,19 @@ 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) { @@ -1109,7 +1138,7 @@ 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; -- 2.1.0