From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51199) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YsnPj-000634-JG for qemu-devel@nongnu.org; Thu, 14 May 2015 03:18:40 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YsnPi-0003gn-Iz for qemu-devel@nongnu.org; Thu, 14 May 2015 03:18:39 -0400 Message-ID: <55544BE3.6080301@huawei.com> Date: Thu, 14 May 2015 15:16:51 +0800 From: Gonglei MIME-Version: 1.0 References: <1431076567-30371-1-git-send-email-wency@cn.fujitsu.com> <1431076567-30371-3-git-send-email-wency@cn.fujitsu.com> In-Reply-To: <1431076567-30371-3-git-send-email-wency@cn.fujitsu.com> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Subject: Re: [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: Wen Congyang , qemu devel , Fam Zheng , Max Reitz , Paolo Bonzini Cc: Kevin Wolf , Lai Jiangshan , qemu block , Jiang Yunhong , Dong Eddie , "Dr. David Alan Gilbert" , Stefan Hajnoczi , Yang Hongyang , zhanghailiang On 2015/5/8 17:15, Wen Congyang wrote: > 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; Oh, This will leak memory which local variable local_err pointed. Besides, do we need to propagate the error info? Regards, -Gonglei > + } > + 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; >