Fix: UST consumer sync all available metadata

[lttng-tools.git] / src / common / consumer-stream.c

diff --git a/src/common/consumer-stream.c b/src/common/consumer-stream.c
index a9e4deef5106d4b3ccb9725d1bcb95418209af27..8fe02e74eaa8dfe59b90ed4fbe2d6b4cf13b637b 100644 (file)
--- a/src/common/consumer-stream.c
+++ b/src/common/consumer-stream.c
@@ -391,45 +391,20 @@ error:
 }
 
 /*
- * Synchronize the metadata using a given session ID. A successful acquisition
- * of a metadata stream will trigger a request to the session daemon and a
- * snapshot so the metadata thread can consume it.
+ * Actually do the metadata sync using the given metadata stream.
  *
- * This function call is a rendez-vous point between the metadata thread and
- * the data thread.
- *
- * Return 0 on success or else a negative value.
+ * Return 0 on success else a negative value. ENODATA can be returned also
+ * indicating that there is no metadata available for that stream.
  */
-int consumer_stream_sync_metadata(struct lttng_consumer_local_data *ctx,
-               uint64_t session_id)
+static int do_sync_metadata(struct lttng_consumer_stream *metadata,
+               struct lttng_consumer_local_data *ctx)
 {
        int ret;
-       struct lttng_consumer_stream *metadata = NULL, *stream = NULL;
-       struct lttng_ht_iter iter;
-       struct lttng_ht *ht;
 
+       assert(metadata);
+       assert(metadata->metadata_flag);
        assert(ctx);
 
-       /* Ease our life a bit. */
-       ht = consumer_data.stream_list_ht;
-
-       rcu_read_lock();
-
-       /* Search the metadata associated with the session id of the given stream. */
-
-       cds_lfht_for_each_entry_duplicate(ht->ht,
-                       ht->hash_fct(&session_id, lttng_ht_seed), ht->match_fct,
-                       &session_id, &iter.iter, stream, node_session_id.node) {
-               if (stream->metadata_flag) {
-                       metadata = stream;
-                       break;
-               }
-       }
-       if (!metadata) {
-               ret = 0;
-               goto end_unlock_rcu;
-       }
-
        /*
         * In UST, since we have to write the metadata from the cache packet
         * by packet, we might need to start this procedure multiple times
@@ -515,12 +490,61 @@ int consumer_stream_sync_metadata(struct lttng_consumer_local_data *ctx,
                pthread_mutex_unlock(&metadata->metadata_rdv_lock);
        } while (ret == EAGAIN);
 
-       ret = 0;
-       goto end_unlock_rcu;
+       /* Success */
+       return 0;
 
 end_unlock_mutex:
        pthread_mutex_unlock(&metadata->lock);
-end_unlock_rcu:
+       return ret;
+}
+
+/*
+ * Synchronize the metadata using a given session ID. A successful acquisition
+ * of a metadata stream will trigger a request to the session daemon and a
+ * snapshot so the metadata thread can consume it.
+ *
+ * This function call is a rendez-vous point between the metadata thread and
+ * the data thread.
+ *
+ * Return 0 on success or else a negative value.
+ */
+int consumer_stream_sync_metadata(struct lttng_consumer_local_data *ctx,
+               uint64_t session_id)
+{
+       int ret;
+       struct lttng_consumer_stream *stream = NULL;
+       struct lttng_ht_iter iter;
+       struct lttng_ht *ht;
+
+       assert(ctx);
+
+       /* Ease our life a bit. */
+       ht = consumer_data.stream_list_ht;
+
+       rcu_read_lock();
+
+       /* Search the metadata associated with the session id of the given stream. */
+
+       cds_lfht_for_each_entry_duplicate(ht->ht,
+                       ht->hash_fct(&session_id, lttng_ht_seed), ht->match_fct,
+                       &session_id, &iter.iter, stream, node_session_id.node) {
+               if (!stream->metadata_flag) {
+                       continue;
+               }
+
+               ret = do_sync_metadata(stream, ctx);
+               if (ret < 0) {
+                       goto end;
+               }
+       }
+
+       /*
+        * Force return code to 0 (success) since ret might be ENODATA for instance
+        * which is not an error but rather that we should come back.
+        */
+       ret = 0;
+
+end:
        rcu_read_unlock();
        return ret;
 }