Fix: ust-consumer: metadata thread not woken-up after version change

[lttng-tools.git] / src / common / consumer / consumer-metadata-cache.h

diff --git a/src/common/consumer/consumer-metadata-cache.h b/src/common/consumer/consumer-metadata-cache.h
index 8ce7f30b19ee7d795af047ca35f78fbf9b7f3ecb..43136858247e764d98d7ad0a857688043fb06b8a 100644 (file)
--- a/src/common/consumer/consumer-metadata-cache.h
+++ b/src/common/consumer/consumer-metadata-cache.h
@@ -21,9 +21,34 @@
 
 #include <common/consumer/consumer.h>
 
+enum consumer_metadata_cache_write_status {
+       CONSUMER_METADATA_CACHE_WRITE_STATUS_ERROR = -1,
+       /*
+        * New metadata content was appended to the cache successfully.
+        * Previously available content remains valid.
+        */
+       CONSUMER_METADATA_CACHE_WRITE_STATUS_APPENDED_CONTENT = 0,
+       /*
+        * The new content pushed to the cache invalidated the content that
+        * was already present. The contents of the cache should be re-read.
+        */
+       CONSUMER_METADATA_CACHE_WRITE_STATUS_INVALIDATED,
+       /*
+        * A metadata cache write can simply overwrite an already existing
+        * section of the cache (and it should be a write-through with identical
+        * data). From the caller's standpoint, there is no change to the state
+        * of the cache.
+        */
+       CONSUMER_METADATA_CACHE_WRITE_STATUS_NO_CHANGE,
+};
+
 struct consumer_metadata_cache {
        char *data;
        uint64_t cache_alloc_size;
+       /*
+        * Current version of the metadata cache.
+        */
+       uint64_t version;
        /*
         * The upper-limit of data written inside the buffer.
         *
@@ -41,8 +66,10 @@ struct consumer_metadata_cache {
        pthread_mutex_t lock;
 };
 
-int consumer_metadata_cache_write(struct lttng_consumer_channel *channel,
-               unsigned int offset, unsigned int len, char *data);
+enum consumer_metadata_cache_write_status
+consumer_metadata_cache_write(struct lttng_consumer_channel *channel,
+               unsigned int offset, unsigned int len, uint64_t version,
+               char *data);
 int consumer_metadata_cache_allocate(struct lttng_consumer_channel *channel);
 void consumer_metadata_cache_destroy(struct lttng_consumer_channel *channel);
 int consumer_metadata_cache_flushed(struct lttng_consumer_channel *channel,