X-Git-Url: https://git.liburcu.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fbin%2Flttng-relayd%2Flive.cpp;h=f1f97f91748b9337c43636d2949cf77b187ed336;hp=99037e417c0db58cd76e267383a9f3f7dc1bd068;hb=55d3f5e528059267f44fb24b179b992bf2b0cfa6;hpb=c56468d0ccfba50baa889b2b9728aff09480d4e0

diff --git a/src/bin/lttng-relayd/live.cpp b/src/bin/lttng-relayd/live.cpp
index 99037e417..f1f97f917 100644
--- a/src/bin/lttng-relayd/live.cpp
+++ b/src/bin/lttng-relayd/live.cpp
@@ -2128,6 +2128,7 @@ static int viewer_get_metadata(struct relay_connection *conn)
 	struct lttng_viewer_get_metadata request;
 	struct lttng_viewer_metadata_packet reply;
 	struct relay_viewer_stream *vstream = nullptr;
+	bool dispose_of_stream = false;
 
 	LTTNG_ASSERT(conn);
 
@@ -2156,6 +2157,9 @@ static int viewer_get_metadata(struct relay_connection *conn)
 		reply.status = htobe32(LTTNG_VIEWER_METADATA_ERR);
 		goto send_reply;
 	}
+
+	pthread_mutex_lock(&vstream->stream->trace->session->lock);
+	pthread_mutex_lock(&vstream->stream->trace->lock);
 	pthread_mutex_lock(&vstream->stream->lock);
 	if (!vstream->stream->is_metadata) {
 		ERR("Invalid metadata stream");
@@ -2164,10 +2168,6 @@ static int viewer_get_metadata(struct relay_connection *conn)
 
 	if (vstream->metadata_sent >= vstream->stream->metadata_received) {
 		/*
-		 * The live viewers expect to receive a NO_NEW_METADATA
-		 * status before a stream disappears, otherwise they abort the
-		 * entire live connection when receiving an error status.
-		 *
 		 * Clear feature resets the metadata_received to 0 until the
 		 * same metadata is received again.
 		 */
@@ -2176,20 +2176,7 @@ static int viewer_get_metadata(struct relay_connection *conn)
 		 * The live viewer considers a closed 0 byte metadata stream as
 		 * an error.
 		 */
-		if (vstream->metadata_sent > 0) {
-			if (vstream->stream->closed && vstream->stream->no_new_metadata_notified) {
-				/*
-				 * Release ownership for the viewer metadata
-				 * stream. Note that this reference is the
-				 * viewer's reference. The vstream still exists
-				 * until the end of the function as
-				 * viewer_stream_get_by_id() took a reference.
-				 */
-				viewer_stream_put(vstream);
-			}
-
-			vstream->stream->no_new_metadata_notified = true;
-		}
+		dispose_of_stream = vstream->metadata_sent > 0 && vstream->stream->closed;
 		goto send_reply;
 	}
 
@@ -2227,6 +2214,19 @@ static int viewer_get_metadata(struct relay_connection *conn)
 	len = vstream->stream->metadata_received - vstream->metadata_sent;
 
 	if (!vstream->stream_file.trace_chunk) {
+		if (vstream->stream->trace->session->connection_closed) {
+			/*
+			 * If the connection is closed, there is no way for the metadata stream
+			 * to ever transition back to an active chunk. As such, signal to the viewer
+			 * that there is no new metadata available.
+			 *
+			 * The stream can be disposed-of. On the next execution of this command,
+			 * the relay daemon will reply with an error status since the stream can't
+			 * be found.
+			 */
+			dispose_of_stream = true;
+		}
+
 		reply.status = htobe32(LTTNG_VIEWER_NO_NEW_METADATA);
 		len = 0;
 		goto send_reply;
@@ -2357,6 +2357,8 @@ send_reply:
 	health_code_update();
 	if (vstream) {
 		pthread_mutex_unlock(&vstream->stream->lock);
+		pthread_mutex_unlock(&vstream->stream->trace->lock);
+		pthread_mutex_unlock(&vstream->stream->trace->session->lock);
 	}
 	ret = send_response(conn->sock, &reply, sizeof(reply));
 	if (ret < 0) {
@@ -2382,7 +2384,22 @@ end_free:
 end:
 	if (vstream) {
 		viewer_stream_put(vstream);
+		if (dispose_of_stream) {
+			/*
+			 * Trigger the destruction of the viewer stream
+			 * by releasing its global reference.
+			 *
+			 * The live viewers expect to receive a NO_NEW_METADATA
+			 * status before a stream disappears, otherwise they abort the
+			 * entire live connection when receiving an error status.
+			 *
+			 * On the next query for this stream, an error will be reported to the
+			 * client.
+			 */
+			viewer_stream_put(vstream);
+		}
 	}
+
 	return ret;
 }