On 2015/5/8 17:15, Wen Congyang wrote: > Signed-off-by: Wen Congyang <we...@cn.fujitsu.com> > Signed-off-by: zhanghailiang <zhang.zhanghaili...@huawei.com> > Signed-off-by: Gonglei <arei.gong...@huawei.com> > --- > 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; >