X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=src%2Fcommon%2Fust-consumer%2Fust-consumer.c;h=81c05d2da1febfe5fff215e9917195dd4b4d8ab4;hb=c124970bc6f688ba8e13cf21cc9933e291cbb76a;hp=3e9814fdb7ea20f50f8156d476c564b362e5e651;hpb=6791112142b503d8f92cca737cc37215b1057568;p=lttng-tools.git

diff --git a/src/common/ust-consumer/ust-consumer.c b/src/common/ust-consumer/ust-consumer.c
index 3e9814fdb..81c05d2da 100644
--- a/src/common/ust-consumer/ust-consumer.c
+++ b/src/common/ust-consumer/ust-consumer.c
@@ -1288,6 +1288,17 @@ error_unlock:
 	return ret;
 }
 
+static
+void metadata_stream_reset_cache_consumed_position(
+		struct lttng_consumer_stream *stream)
+{
+	ASSERT_LOCKED(stream->lock);
+
+	DBG("Reset metadata cache of session %" PRIu64,
+			stream->chan->session_id);
+	stream->ust_metadata_pushed = 0;
+}
+
 /*
  * Receive the metadata updates from the sessiond. Supports receiving
  * overlapping metadata, but is needs to always belong to a contiguous
@@ -1302,6 +1313,7 @@ int lttng_ustconsumer_recv_metadata(int sock, uint64_t key, uint64_t offset,
 {
 	int ret, ret_code = LTTCOMM_CONSUMERD_SUCCESS;
 	char *metadata_str;
+	enum consumer_metadata_cache_write_status cache_write_status;
 
 	DBG("UST consumer push metadata key %" PRIu64 " of len %" PRIu64, key, len);
 
@@ -1325,10 +1337,40 @@ int lttng_ustconsumer_recv_metadata(int sock, uint64_t key, uint64_t offset,
 	health_code_update();
 
 	pthread_mutex_lock(&channel->metadata_cache->lock);
-	ret = consumer_metadata_cache_write(channel, offset, len, version,
-			metadata_str);
+	cache_write_status = consumer_metadata_cache_write(
+			channel, offset, len, version, metadata_str);
 	pthread_mutex_unlock(&channel->metadata_cache->lock);
-	if (ret < 0) {
+	switch (cache_write_status) {
+	case CONSUMER_METADATA_CACHE_WRITE_STATUS_NO_CHANGE:
+		/*
+		 * The write entirely overlapped with existing contents of the
+		 * same metadata version (same content); there is nothing to do.
+		 */
+		break;
+	case CONSUMER_METADATA_CACHE_WRITE_STATUS_INVALIDATED:
+		/*
+		 * The metadata cache was invalidated (previously pushed
+		 * content has been overwritten). Reset the stream's consumed
+		 * metadata position to ensure the metadata poll thread consumes
+		 * the whole cache.
+		 */
+		pthread_mutex_lock(&channel->metadata_stream->lock);
+		metadata_stream_reset_cache_consumed_position(
+				channel->metadata_stream);
+		pthread_mutex_unlock(&channel->metadata_stream->lock);
+		/* Fall-through. */
+	case CONSUMER_METADATA_CACHE_WRITE_STATUS_APPENDED_CONTENT:
+		/*
+		 * In both cases, the metadata poll thread has new data to
+		 * consume.
+		 */
+		ret = consumer_metadata_wakeup_pipe(channel);
+		if (ret) {
+			ret_code = LTTCOMM_CONSUMERD_ERROR_METADATA;
+			goto end_free;
+		}
+		break;
+	case CONSUMER_METADATA_CACHE_WRITE_STATUS_ERROR:
 		/* Unable to handle metadata. Notify session daemon. */
 		ret_code = LTTCOMM_CONSUMERD_ERROR_METADATA;
 		/*
@@ -1337,6 +1379,8 @@ int lttng_ustconsumer_recv_metadata(int sock, uint64_t key, uint64_t offset,
 		 * waiting for the metadata cache to be flushed.
 		 */
 		goto end_free;
+	default:
+		abort();
 	}
 
 	if (!wait) {
@@ -2416,15 +2460,6 @@ int lttng_ustconsumer_close_wakeup_fd(struct lttng_consumer_stream *stream)
 	return ustctl_stream_close_wakeup_fd(stream->ustream);
 }
 
-static
-void metadata_stream_reset_cache_consumed_position(
-		struct lttng_consumer_stream *stream)
-{
-	DBG("Reset metadata cache of session %" PRIu64,
-			stream->chan->session_id);
-	stream->ust_metadata_pushed = 0;
-}
-
 /*
  * Write up to one packet from the metadata cache to the channel.
  *
@@ -3002,6 +3037,7 @@ int lttng_ustconsumer_data_pending(struct lttng_consumer_stream *stream)
 
 	assert(stream);
 	assert(stream->ustream);
+	ASSERT_LOCKED(stream->lock);
 
 	DBG("UST consumer checking data pending");