Fix: relayd: missing metadata stream causes all traces to be skipped

[lttng-tools.git] / src / bin / lttng-relayd / live.c

diff --git a/src/bin/lttng-relayd/live.c b/src/bin/lttng-relayd/live.c
index 9a3d78ef0fc3a0632476d131202b325d77e17e82..f00f07db1b8e63fc280c5a868379da2a47a68ade 100644 (file)
--- a/src/bin/lttng-relayd/live.c
+++ b/src/bin/lttng-relayd/live.c
@@ -291,6 +291,13 @@ static int make_viewer_streams(struct relay_session *session,
        assert(session);
        ASSERT_LOCKED(session->lock);
 
+       if (!viewer_trace_chunk) {
+               ERR("Internal error: viewer session associated with session \"%s\" has a NULL trace chunk",
+                               session->session_name);
+               ret = -1;
+               goto error;
+       }
+
        if (session->connection_closed) {
                *closed = true;
        }
@@ -302,6 +309,7 @@ static int make_viewer_streams(struct relay_session *session,
        rcu_read_lock();
        cds_lfht_for_each_entry(session->ctf_traces_ht->ht, &iter.iter, ctf_trace,
                        node.node) {
+               bool trace_has_metadata_stream = false;
                struct relay_stream *stream;
 
                health_code_update();
@@ -310,6 +318,30 @@ static int make_viewer_streams(struct relay_session *session,
                        continue;
                }
 
+               /*
+                * Iterate over all the streams of the trace to see if we have a
+                * metadata stream.
+                */
+               cds_list_for_each_entry_rcu(
+                               stream, &ctf_trace->stream_list, stream_node)
+               {
+                       if (stream->is_metadata) {
+                               trace_has_metadata_stream = true;
+                               break;
+                       }
+               }
+
+               /*
+                * If there is no metadata stream in this trace at the moment
+                * and we never sent one to the viewer, skip the trace. We
+                * accept that the viewer will not see this trace at all.
+                */
+               if (!trace_has_metadata_stream &&
+                               !ctf_trace->metadata_stream_sent_to_viewer) {
+                       ctf_trace_put(ctf_trace);
+                       continue;
+               }
+
                cds_list_for_each_entry_rcu(stream, &ctf_trace->stream_list, stream_node) {
                        struct relay_viewer_stream *vstream;
 
@@ -324,6 +356,15 @@ static int make_viewer_streams(struct relay_session *session,
                        }
                        vstream = viewer_stream_get_by_id(stream->stream_handle);
                        if (!vstream) {
+                               /*
+                                * Save that we sent the metadata stream to the
+                                * viewer. So that we know what trace the viewer
+                                * is aware of.
+                                */
+                               if (stream->is_metadata) {
+                                       ctf_trace->metadata_stream_sent_to_viewer =
+                                                       true;
+                               }
                                vstream = viewer_stream_create(stream,
                                                viewer_trace_chunk, seek_t);
                                if (!vstream) {
@@ -378,6 +419,7 @@ static int make_viewer_streams(struct relay_session *session,
 
 error_unlock:
        rcu_read_unlock();
+error:
        return ret;
 }
 
@@ -959,25 +1001,6 @@ int viewer_get_new_streams(struct relay_connection *conn)
        }
 
        pthread_mutex_lock(&session->lock);
-       if (!session->current_trace_chunk) {
-               /*
-                * Means the session is being destroyed. React the same way
-                * as if it could not be found at all.
-                */
-               DBG("Relay session %" PRIu64 " has no current trace chunk, replying LTTNG_VIEWER_NEW_STREAMS_ERR",
-                               session_id);
-               response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_ERR);
-               goto send_reply_unlock;
-       }
-
-       if (!conn->viewer_session->current_trace_chunk &&
-                       session->current_trace_chunk) {
-               ret = viewer_session_set_trace_chunk(conn->viewer_session,
-                               session->current_trace_chunk);
-               if (ret) {
-                       goto error_unlock_session;
-               }
-       }
        ret = make_viewer_streams(session,
                        conn->viewer_session->current_trace_chunk,
                        LTTNG_VIEWER_SEEK_LAST, &nb_total, &nb_unsent,
@@ -1057,6 +1080,7 @@ int viewer_attach_session(struct relay_connection *conn)
        struct lttng_viewer_attach_session_request request;
        struct lttng_viewer_attach_session_response response;
        struct relay_session *session = NULL;
+       enum lttng_viewer_attach_return_code viewer_attach_status;
        bool closed = false;
        uint64_t session_id;
 
@@ -1106,10 +1130,10 @@ int viewer_attach_session(struct relay_connection *conn)
        }
 
        send_streams = 1;
-       ret = viewer_session_attach(conn->viewer_session, session);
-       if (ret) {
-               DBG("Already a viewer attached");
-               response.status = htobe32(LTTNG_VIEWER_ATTACH_ALREADY);
+       viewer_attach_status = viewer_session_attach(conn->viewer_session,
+                       session);
+       if (viewer_attach_status != LTTNG_VIEWER_ATTACH_OK) {
+               response.status = htobe32(viewer_attach_status);
                goto send_reply;
        }
 
@@ -1126,14 +1150,6 @@ int viewer_attach_session(struct relay_connection *conn)
                goto send_reply;
        }
 
-       if (!conn->viewer_session->current_trace_chunk &&
-                       session->current_trace_chunk) {
-               ret = viewer_session_set_trace_chunk(conn->viewer_session,
-                               session->current_trace_chunk);
-               if (ret) {
-                       goto end_put_session;
-               }
-       }
        ret = make_viewer_streams(session,
                        conn->viewer_session->current_trace_chunk, seek_type,
                        &nb_streams, NULL, NULL, &closed);