+ if (stream->chan->metadata_cache->max_offset ==
+ stream->ust_metadata_pushed) {
+ /*
+ * In the context of a user space metadata channel, a
+ * change in version can be detected in two ways:
+ * 1) During the pre-consume of the `read_subbuffer` loop,
+ * 2) When populating the metadata ring buffer (i.e. here).
+ *
+ * This function is invoked when there is no metadata
+ * available in the ring-buffer. If all data was consumed
+ * up to the size of the metadata cache, there is no metadata
+ * to insert in the ring-buffer.
+ *
+ * However, the metadata version could still have changed (a
+ * regeneration without any new data will yield the same cache
+ * size).
+ *
+ * The cache's version is checked for a version change and the
+ * consumed position is reset if one occurred.
+ *
+ * This check is only necessary for the user space domain as
+ * it has to manage the cache explicitly. If this reset was not
+ * performed, no metadata would be consumed (and no reset would
+ * occur as part of the pre-consume) until the metadata size
+ * exceeded the cache size.
+ */
+ if (stream->metadata_version !=
+ stream->chan->metadata_cache->version) {
+ metadata_stream_reset_cache_consumed_position(stream);
+ consumer_stream_metadata_set_version(stream,
+ stream->chan->metadata_cache->version);
+ } else {
+ ret = 0;
+ goto end;
+ }