X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=src%2Fcommon%2Fust-consumer%2Fust-consumer.c;h=88b687611fc8714675722f8616a85b10fce40baa;hb=269cb2a1da5ba1baf63304dfa9cefd3cab4401b9;hp=366f8550bf03774db161b6d70bd34765f9005869;hpb=3ab4ee7d2fec586872739cd0f6e58bd4ed54b78a;p=lttng-tools.git

diff --git a/src/common/ust-consumer/ust-consumer.c b/src/common/ust-consumer/ust-consumer.c
index 366f8550b..88b687611 100644
--- a/src/common/ust-consumer/ust-consumer.c
+++ b/src/common/ust-consumer/ust-consumer.c
@@ -768,10 +768,19 @@ static int flush_channel(uint64_t chan_key)
 		health_code_update();
 
 		pthread_mutex_lock(&stream->lock);
+
+		/*
+		 * Protect against concurrent teardown of a stream.
+		 */
+		if (cds_lfht_is_node_deleted(&stream->node.node)) {
+			goto next;
+		}
+
 		if (!stream->quiescent) {
 			ustctl_flush_buffer(stream->ustream, 0);
 			stream->quiescent = true;
 		}
+next:
 		pthread_mutex_unlock(&stream->lock);
 	}
 error:
@@ -831,6 +840,7 @@ static int close_metadata(uint64_t chan_key)
 {
 	int ret = 0;
 	struct lttng_consumer_channel *channel;
+	unsigned int channel_monitor;
 
 	DBG("UST consumer close metadata key %" PRIu64, chan_key);
 
@@ -849,13 +859,48 @@ static int close_metadata(uint64_t chan_key)
 
 	pthread_mutex_lock(&consumer_data.lock);
 	pthread_mutex_lock(&channel->lock);
-
+	channel_monitor = channel->monitor;
 	if (cds_lfht_is_node_deleted(&channel->node.node)) {
 		goto error_unlock;
 	}
 
 	lttng_ustconsumer_close_metadata(channel);
+	pthread_mutex_unlock(&channel->lock);
+	pthread_mutex_unlock(&consumer_data.lock);
+
+	/*
+	 * The ownership of a metadata channel depends on the type of
+	 * session to which it belongs. In effect, the monitor flag is checked
+	 * to determine if this metadata channel is in "snapshot" mode or not.
+	 *
+	 * In the non-snapshot case, the metadata channel is created along with
+	 * a single stream which will remain present until the metadata channel
+	 * is destroyed (on the destruction of its session). In this case, the
+	 * metadata stream in "monitored" by the metadata poll thread and holds
+	 * the ownership of its channel.
+	 *
+	 * Closing the metadata will cause the metadata stream's "metadata poll
+	 * pipe" to be closed. Closing this pipe will wake-up the metadata poll
+	 * thread which will teardown the metadata stream which, in return,
+	 * deletes the metadata channel.
+	 *
+	 * In the snapshot case, the metadata stream is created and destroyed
+	 * on every snapshot record. Since the channel doesn't have an owner
+	 * other than the session daemon, it is safe to destroy it immediately
+	 * on reception of the CLOSE_METADATA command.
+	 */
+	if (!channel_monitor) {
+		/*
+		 * The channel and consumer_data locks must be
+		 * released before this call since consumer_del_channel
+		 * re-acquires the channel and consumer_data locks to teardown
+		 * the channel and queue its reclamation by the "call_rcu"
+		 * worker thread.
+		 */
+		consumer_del_channel(channel);
+	}
 
+	return ret;
 error_unlock:
 	pthread_mutex_unlock(&channel->lock);
 	pthread_mutex_unlock(&consumer_data.lock);
@@ -1101,12 +1146,6 @@ static int snapshot_channel(uint64_t key, char *path, uint64_t relayd_id,
 			DBG("UST consumer snapshot stream %s/%s (%" PRIu64 ")", path,
 					stream->name, stream->key);
 		}
-		if (relayd_id != -1ULL) {
-			ret = consumer_send_relayd_streams_sent(relayd_id);
-			if (ret < 0) {
-				goto error_unlock;
-			}
-		}
 
 		/*
 		 * If tracing is active, we want to perform a "full" buffer flush.
@@ -1144,7 +1183,7 @@ static int snapshot_channel(uint64_t key, char *path, uint64_t relayd_id,
 				produced_pos, nb_packets_per_stream,
 				stream->max_sb_size);
 
-		while (consumed_pos < produced_pos) {
+		while ((long) (consumed_pos - produced_pos) < 0) {
 			ssize_t read_len;
 			unsigned long len, padded_len;
 
@@ -2892,7 +2931,7 @@ int lttng_ustconsumer_request_metadata(struct lttng_consumer_local_data *ctx,
 	request.key = channel->key;
 
 	DBG("Sending metadata request to sessiond, session id %" PRIu64
-			", per-pid %" PRIu64 ", app UID %u and channek key %" PRIu64,
+			", per-pid %" PRIu64 ", app UID %u and channel key %" PRIu64,
 			request.session_id, request.session_id_per_pid, request.uid,
 			request.key);