relayd: clarify viewer_get_next_index no rotation condition

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

diff --git a/src/bin/lttng-relayd/live.cpp b/src/bin/lttng-relayd/live.cpp
index 92c3bf4a7831d8ac6195009e08af8dc5e6fceee0..96ec11efcde387e67e8884b63593f705933effb4 100644 (file)
--- a/src/bin/lttng-relayd/live.cpp
+++ b/src/bin/lttng-relayd/live.cpp
@@ -29,6 +29,7 @@
 #include <urcu/futex.h>
 #include <urcu/rculist.h>
 #include <urcu/uatomic.h>
+#include <string>
 
 #include <common/common.h>
 #include <common/compat/endian.h>
@@ -1167,6 +1168,16 @@ int viewer_get_new_streams(struct relay_connection *conn)
         * the viewer's point of view.
         */
        pthread_mutex_lock(&session->lock);
+       /*
+        * If a session rotation is ongoing, do not attempt to open any
+        * stream, because the chunk can be in an intermediate state
+        * due to directory renaming.
+        */
+       if (session->ongoing_rotation) {
+               DBG("Relay session %" PRIu64 " rotation ongoing", session_id);
+               response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_NO_NEW);
+               goto send_reply_unlock;
+       }
        ret = make_viewer_streams(session,
                        conn->viewer_session,
                        LTTNG_VIEWER_SEEK_BEGINNING, &nb_total, &nb_unsent,
@@ -1307,6 +1318,17 @@ int viewer_attach_session(struct relay_connection *conn)
                goto send_reply;
        }
 
+       /*
+        * If a session rotation is ongoing, do not attempt to open any
+        * stream, because the chunk can be in an intermediate state
+        * due to directory renaming.
+        */
+       if (session->ongoing_rotation) {
+               DBG("Relay session %" PRIu64 " rotation ongoing", session_id);
+               send_streams = 0;
+               goto send_reply;
+       }
+
        ret = make_viewer_streams(session,
                        conn->viewer_session, seek_type,
                        &nb_streams, NULL, NULL, &closed);
@@ -1581,6 +1603,9 @@ int viewer_get_next_index(struct relay_connection *conn)
        struct relay_stream *rstream = NULL;
        struct ctf_trace *ctf_trace = NULL;
        struct relay_viewer_stream *metadata_viewer_stream = NULL;
+       bool viewer_stream_and_session_in_same_chunk, viewer_stream_one_rotation_behind;
+       uint64_t stream_file_chunk_id = -1ULL, viewer_session_chunk_id = -1ULL;
+       enum lttng_trace_chunk_status status;
 
        LTTNG_ASSERT(conn);
 
@@ -1661,12 +1686,50 @@ int viewer_get_next_index(struct relay_connection *conn)
         * This allows clients to consume all the packets of a trace chunk
         * after a session's destruction.
         */
-       if (conn->viewer_session->current_trace_chunk != vstream->stream_file.trace_chunk &&
-                       !(rstream->completed_rotation_count == vstream->last_seen_rotation_count + 1 && !rstream->trace_chunk)) {
-               DBG("Viewer session and viewer stream chunk differ: "
-                               "vsession chunk %p vstream chunk %p",
+       if (vstream->stream_file.trace_chunk) {
+               status = lttng_trace_chunk_get_id(
+                               vstream->stream_file.trace_chunk,
+                               &stream_file_chunk_id);
+               LTTNG_ASSERT(status == LTTNG_TRACE_CHUNK_STATUS_OK);
+       }
+       if (conn->viewer_session->current_trace_chunk) {
+               status = lttng_trace_chunk_get_id(
                                conn->viewer_session->current_trace_chunk,
-                               vstream->stream_file.trace_chunk);
+                               &viewer_session_chunk_id);
+               LTTNG_ASSERT(status == LTTNG_TRACE_CHUNK_STATUS_OK);
+       }
+
+       viewer_stream_and_session_in_same_chunk = lttng_trace_chunk_ids_equal(
+                       conn->viewer_session->current_trace_chunk,
+                       vstream->stream_file.trace_chunk);
+       viewer_stream_one_rotation_behind = rstream->completed_rotation_count ==
+                       vstream->last_seen_rotation_count + 1;
+
+       if (viewer_stream_and_session_in_same_chunk) {
+               DBG("Transition to latest chunk check (%s -> %s): Same chunk, no need to rotate",
+                               vstream->stream_file.trace_chunk ?
+                                               std::to_string(stream_file_chunk_id).c_str() :
+                                               "None",
+                               conn->viewer_session->current_trace_chunk ?
+                                               std::to_string(viewer_session_chunk_id).c_str() :
+                                               "None");
+       } else if (viewer_stream_one_rotation_behind && !rstream->trace_chunk) {
+               DBG("Transition to latest chunk check (%s -> %s): One chunk behind relay stream which is being destroyed, no need to rotate",
+                               vstream->stream_file.trace_chunk ?
+                                               std::to_string(stream_file_chunk_id).c_str() :
+                                               "None",
+                               conn->viewer_session->current_trace_chunk ?
+                                               std::to_string(viewer_session_chunk_id).c_str() :
+                                               "None");
+       } else {
+               DBG("Transition to latest chunk check (%s -> %s): Viewer stream chunk ID and viewer session chunk ID differ, rotating viewer stream",
+                               vstream->stream_file.trace_chunk ?
+                                               std::to_string(stream_file_chunk_id).c_str() :
+                                               "None",
+                               conn->viewer_session->current_trace_chunk ?
+                                               std::to_string(viewer_session_chunk_id).c_str() :
+                                               "None");
+
                viewer_stream_rotate_to_trace_chunk(vstream,
                                conn->viewer_session->current_trace_chunk);
                vstream->last_seen_rotation_count =
@@ -1711,7 +1774,6 @@ int viewer_get_next_index(struct relay_connection *conn)
         */
        if (!vstream->stream_file.handle) {
                char file_path[LTTNG_PATH_MAX];
-               enum lttng_trace_chunk_status status;
                struct fs_handle *fs_handle;
 
                ret = utils_stream_file_path(rstream->path_name,
@@ -2006,11 +2068,11 @@ int viewer_get_metadata(struct relay_connection *conn)
                 * an error.
                 */
                if (vstream->metadata_sent > 0) {
-                       vstream->stream->no_new_metadata_notified = true;
-                       if (vstream->stream->closed) {
+                       if (vstream->stream->closed && vstream->stream->no_new_metadata_notified) {
                                /* Release ownership for the viewer metadata stream. */
                                viewer_stream_put(vstream);
                        }
+                       vstream->stream->no_new_metadata_notified = true;
                }
                goto send_reply;
        }
@@ -2032,8 +2094,8 @@ int viewer_get_metadata(struct relay_connection *conn)
        }
 
        if (conn->viewer_session->current_trace_chunk &&
-                       conn->viewer_session->current_trace_chunk !=
-                                       vstream->stream_file.trace_chunk) {
+                       !lttng_trace_chunk_ids_equal(conn->viewer_session->current_trace_chunk,
+                                       vstream->stream_file.trace_chunk)) {
                bool acquired_reference;
 
                DBG("Viewer session and viewer stream chunk differ: "