char backing_name[PATH_MAX];
QDict *options = NULL;
- if (bs->backing_format[0] != '\0') {
- options = qdict_new();
- qdict_put_str(options, "driver", bs->backing_format);
- }
-
- if (force_share) {
- if (!options) {
+ if (bs->backing) {
+ if (bs->backing_format[0] != '\0') {
options = qdict_new();
+ qdict_put_str(options, "driver", bs->backing_format);
}
- qdict_put_bool(options, BDRV_OPT_FORCE_SHARE, true);
- }
- bdrv_get_backing_filename(bs, backing_name, sizeof(backing_name));
- blk_old_backing = blk_new_open(backing_name, NULL,
- options, src_flags, &local_err);
- if (!blk_old_backing) {
- error_reportf_err(local_err,
- "Could not open old backing file '%s': ",
- backing_name);
- ret = -1;
- goto out;
+
+ if (force_share) {
+ if (!options) {
+ options = qdict_new();
+ }
+ qdict_put_bool(options, BDRV_OPT_FORCE_SHARE, true);
+ }
+ bdrv_get_backing_filename(bs, backing_name, sizeof(backing_name));
+ blk_old_backing = blk_new_open(backing_name, NULL,
+ options, src_flags, &local_err);
+ if (!blk_old_backing) {
+ error_reportf_err(local_err,
+ "Could not open old backing file '%s': ",
+ backing_name);
+ ret = -1;
+ goto out;
+ }
+ } else {
+ blk_old_backing = NULL;
}
if (out_baseimg[0]) {
*/
if (!unsafe) {
int64_t size;
- int64_t old_backing_size;
+ int64_t old_backing_size = 0;
int64_t new_backing_size = 0;
uint64_t offset;
int64_t n;
ret = -1;
goto out;
}
- old_backing_size = blk_getlength(blk_old_backing);
- if (old_backing_size < 0) {
- char backing_name[PATH_MAX];
+ if (blk_old_backing) {
+ old_backing_size = blk_getlength(blk_old_backing);
+ if (old_backing_size < 0) {
+ char backing_name[PATH_MAX];
- bdrv_get_backing_filename(bs, backing_name, sizeof(backing_name));
- error_report("Could not get size of '%s': %s",
- backing_name, strerror(-old_backing_size));
- ret = -1;
- goto out;
+ bdrv_get_backing_filename(bs, backing_name,
+ sizeof(backing_name));
+ error_report("Could not get size of '%s': %s",
+ backing_name, strerror(-old_backing_size));
+ ret = -1;
+ goto out;
+ }
}
if (blk_new_backing) {
new_backing_size = blk_getlength(blk_new_backing);