On 05/14/2015 03:16 PM, Gonglei wrote: > 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?
Yes, we need to propaget the error info. I also forget to free options. Will fix it in the next version. Thanks Wen Congyang > > 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; >> > > > . >