X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fbin%2Flttng-relayd%2Fstream.c;h=8825d094ce57b389662667bfd5d567ca0ed77cfd;hp=2a59d1ed3e166edd319209ea97065eebf81e3876;hb=49e614cb2878f0664c9f44f9f24cb1d81116de21;hpb=bda7c7b9b4c633de16f3d8bf109f9d21fdd9a5fb

diff --git a/src/bin/lttng-relayd/stream.c b/src/bin/lttng-relayd/stream.c
index 2a59d1ed3..8825d094c 100644
--- a/src/bin/lttng-relayd/stream.c
+++ b/src/bin/lttng-relayd/stream.c
@@ -253,6 +253,11 @@ static void stream_unpublish(struct relay_stream *stream)
 static void stream_destroy(struct relay_stream *stream)
 {
 	if (stream->indexes_ht) {
+		/*
+		 * Calling lttng_ht_destroy in call_rcu worker thread so
+		 * we don't hold the RCU read-side lock while calling
+		 * it.
+		 */
 		lttng_ht_destroy(stream->indexes_ht);
 	}
 	if (stream->tfa) {
@@ -354,26 +359,59 @@ void try_stream_close(struct relay_stream *stream)
 	}
 
 	stream->close_requested = true;
-	/*
-	 * We shortcut the data pending check if no bound is known for this
-	 * stream. This prevents us from never closing the stream in the case
-	 * where a connection would be closed before a "close" command has
-	 * been received.
-	 *
-	 * TODO
-	 * This still leaves open the question of handling missing data after
-	 * a bound has been set by a stream close command. Since we have no
-	 * way of pairing data and control connection, and that a data
-	 * connection has no ownership of a stream, it is likely that a
-	 * timeout approach would be appropriate to handle dangling streams.
-	 */
+
+	if (stream->last_net_seq_num == -1ULL) {
+		/*
+		 * Handle connection close without explicit stream close
+		 * command.
+		 *
+		 * We can be clever about indexes partially received in
+		 * cases where we received the data socket part, but not
+		 * the control socket part: since we're currently closing
+		 * the stream on behalf of the control socket, we *know*
+		 * there won't be any more control information for this
+		 * socket. Therefore, we can destroy all indexes for
+		 * which we have received only the file descriptor (from
+		 * data socket). This takes care of consumerd crashes
+		 * between sending the data and control information for
+		 * a packet. Since those are sent in that order, we take
+		 * care of consumerd crashes.
+		 */
+		relay_index_close_partial_fd(stream);
+		/*
+		 * Use the highest net_seq_num we currently have pending
+		 * As end of stream indicator.  Leave last_net_seq_num
+		 * at -1ULL if we cannot find any index.
+		 */
+		stream->last_net_seq_num = relay_index_find_last(stream);
+		/* Fall-through into the next check. */
+	}
+
 	if (stream->last_net_seq_num != -1ULL &&
 			((int64_t) (stream->prev_seq - stream->last_net_seq_num)) < 0) {
-		/* Don't close since we still have data pending. */
+		/*
+		 * Don't close since we still have data pending. This
+		 * handles cases where an explicit close command has
+		 * been received for this stream, and cases where the
+		 * connection has been closed, and we are awaiting for
+		 * index information from the data socket. It is
+		 * therefore expected that all the index fd information
+		 * we need has already been received on the control
+		 * socket. Matching index information from data socket
+		 * should be Expected Soon(TM).
+		 *
+		 * TODO: We should implement a timer to garbage collect
+		 * streams after a timeout to be resilient against a
+		 * consumerd implementation that would not match this
+		 * expected behavior.
+		 */
 		pthread_mutex_unlock(&stream->lock);
 		DBG("closing stream %" PRIu64 " aborted since it still has data pending", stream->stream_handle);
 		return;
 	}
+	/*
+	 * We received all the indexes we can expect.
+	 */
 	stream_unpublish(stream);
 	stream->closed = true;
 	/* Relay indexes are only used by the "consumer/sessiond" end. */
@@ -383,6 +421,27 @@ void try_stream_close(struct relay_stream *stream)
 	stream_put(stream);
 }
 
+static void print_stream_indexes(struct relay_stream *stream)
+{
+	struct lttng_ht_iter iter;
+	struct relay_index *index;
+
+	rcu_read_lock();
+	cds_lfht_for_each_entry(stream->indexes_ht->ht, &iter.iter, index,
+			index_n.node) {
+		DBG("index %p net_seq_num %" PRIu64 " refcount %ld"
+				" stream %" PRIu64 " trace %" PRIu64
+				" session %" PRIu64,
+				index,
+				index->index_n.key,
+				stream->ref.refcount,
+				index->stream->stream_handle,
+				index->stream->trace->id,
+				index->stream->trace->session->id);
+	}
+	rcu_read_unlock();
+}
+
 void print_relay_streams(void)
 {
 	struct lttng_ht_iter iter;
@@ -401,6 +460,7 @@ void print_relay_streams(void)
 				stream->stream_handle,
 				stream->trace->id,
 				stream->trace->session->id);
+		print_stream_indexes(stream);
 		stream_put(stream);
 	}
 	rcu_read_unlock();