X-Git-Url: http://git.efficios.com/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fbin%2Flttng-relayd%2Fviewer-stream.c;h=333246afb3f4d312874cca9cfc144e6cc0fdf932;hp=1d02ee32945200b63142d934565ab83154513953;hb=a44ca2ca85e4b64729f7b88b1919fd6737dfff8a;hpb=9237e6a108fdba7acc014f739d0569565552bdec

diff --git a/src/bin/lttng-relayd/viewer-stream.c b/src/bin/lttng-relayd/viewer-stream.c
index 1d02ee329..333246afb 100644
--- a/src/bin/lttng-relayd/viewer-stream.c
+++ b/src/bin/lttng-relayd/viewer-stream.c
@@ -63,29 +63,59 @@ struct relay_viewer_stream *viewer_stream_create(struct relay_stream *stream,
 		goto error;
 	}
 
+	if (!stream_get(stream)) {
+		ERR("Cannot get stream");
+		goto error;
+	}
+	vstream->stream = stream;
+
+	pthread_mutex_lock(&stream->lock);
+
+	if (stream->is_metadata && stream->trace->viewer_metadata_stream) {
+		ERR("Cannot attach viewer metadata stream to trace (busy).");
+		goto error_unlock;
+	}
+
 	switch (seek_t) {
 	case LTTNG_VIEWER_SEEK_BEGINNING:
-		vstream->current_tracefile_id = stream->oldest_tracefile_id;
+	{
+		uint64_t seq_tail = tracefile_array_get_seq_tail(stream->tfa);
+
+		if (seq_tail == -1ULL) {
+			/*
+			 * Tail may not be initialized yet. Nonetheless, we know
+			 * we want to send the first index once it becomes
+			 * available.
+			 */
+			seq_tail = 0;
+		}
+		vstream->current_tracefile_id =
+			tracefile_array_get_file_index_tail(stream->tfa);
+		vstream->index_sent_seqcount = seq_tail;
 		break;
+	}
 	case LTTNG_VIEWER_SEEK_LAST:
-		vstream->current_tracefile_id = stream->current_tracefile_id;
+		vstream->current_tracefile_id =
+			tracefile_array_get_file_index_head(stream->tfa);
+		/*
+		 * We seek at the very end of each stream, awaiting for
+		 * a future packet to eventually come in.
+		 *
+		 * We don't need to check the head position for -1ULL since the
+		 * increment will set it to 0.
+		 */
+		vstream->index_sent_seqcount =
+				tracefile_array_get_seq_head(stream->tfa) + 1;
 		break;
 	default:
-		goto error;
-	}
-	if (!stream_get(stream)) {
-		ERR("Cannot get stream");
-		goto error;
+		goto error_unlock;
 	}
-	vstream->stream = stream;
 
-	pthread_mutex_lock(&stream->lock);
 	/*
-	 * If we never received an index for the current stream, delay the opening
-	 * of the index, otherwise open it right now.
+	 * If we never received an index for the current stream, delay
+	 * the opening of the index, otherwise open it right now.
 	 */
-	if (vstream->current_tracefile_id == stream->current_tracefile_id
-			&& stream->total_index_received == 0) {
+	if (stream->index_received_seqcount == 0) {
 		vstream->index_fd = NULL;
 	} else {
 		int read_fd;
@@ -112,14 +142,12 @@ struct relay_viewer_stream *viewer_stream_create(struct relay_stream *stream,
 		if (lseek_ret < 0) {
 			goto error_unlock;
 		}
-		vstream->last_sent_index = stream->total_index_received;
 	}
-	pthread_mutex_unlock(&stream->lock);
-
 	if (stream->is_metadata) {
 		rcu_assign_pointer(stream->trace->viewer_metadata_stream,
 				vstream);
 	}
+	pthread_mutex_unlock(&stream->lock);
 
 	/* Globally visible after the add unique. */
 	lttng_ht_node_init_u64(&vstream->stream_n, stream->stream_handle);
@@ -226,26 +254,6 @@ void viewer_stream_put(struct relay_viewer_stream *vstream)
 	rcu_read_unlock();
 }
 
-/*
- * Returns whether the current tracefile is readable. If not, it has
- * been overwritten.
- * Must be called with rstream lock held.
- */
-bool viewer_stream_is_tracefile_seq_readable(struct relay_viewer_stream *vstream,
-		 uint64_t seq)
-{
-	struct relay_stream *stream = vstream->stream;
-
-	if (seq >= stream->oldest_tracefile_seq
-			&& seq <= stream->current_tracefile_seq) {
-		/* seq is a readable file. */
-		return true;
-	} else {
-		/* seq is not readable. */
-		return false;
-	}
-}
-
 /*
  * Rotate a stream to the next tracefile.
  *
@@ -256,9 +264,11 @@ int viewer_stream_rotate(struct relay_viewer_stream *vstream)
 {
 	int ret;
 	struct relay_stream *stream = vstream->stream;
+	uint64_t new_id;
 
 	/* Detect the last tracefile to open. */
-	if (stream->total_index_received == vstream->last_sent_index
+	if (stream->index_received_seqcount
+			== vstream->index_sent_seqcount
 			&& stream->trace->session->connection_closed) {
 		ret = 1;
 		goto end;
@@ -270,17 +280,29 @@ int viewer_stream_rotate(struct relay_viewer_stream *vstream)
 		goto end;
 	}
 
-	if (!viewer_stream_is_tracefile_seq_readable(vstream,
-			vstream->current_tracefile_seq + 1)) {
-		vstream->current_tracefile_id =
-				stream->oldest_tracefile_id;
-		vstream->current_tracefile_seq =
-				stream->oldest_tracefile_seq;
+	/*
+	 * Try to move to the next file.
+	 */
+	new_id = (vstream->current_tracefile_id + 1)
+			% stream->tracefile_count;
+	if (tracefile_array_seq_in_file(stream->tfa, new_id,
+			vstream->index_sent_seqcount)) {
+		vstream->current_tracefile_id = new_id;
 	} else {
+		uint64_t seq_tail = tracefile_array_get_seq_tail(stream->tfa);
+
+		/*
+		 * This can only be reached on overwrite, which implies there
+		 * has been data written at some point, which will have set the
+		 * tail.
+		 */
+		assert(seq_tail != -1ULL);
+		/*
+		 * We need to resync because we lag behind tail.
+		 */
 		vstream->current_tracefile_id =
-				(vstream->current_tracefile_id + 1)
-					% stream->tracefile_count;
-		vstream->current_tracefile_seq++;
+			tracefile_array_get_file_index_tail(stream->tfa);
+		vstream->index_sent_seqcount = seq_tail;
 	}
 
 	if (vstream->index_fd) {