Command metadata regenerate

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

diff --git a/src/common/consumer/consumer-metadata-cache.c b/src/common/consumer/consumer-metadata-cache.c
index 48257c299750aa0953016808766c6a634a17c65e..3211ec1e84878d7735fe2280891719fd9fd308d6 100644 (file)
--- a/src/common/consumer/consumer-metadata-cache.c
+++ b/src/common/consumer/consumer-metadata-cache.c
@@ -70,6 +70,41 @@ end:
        return ret;
 }
 
+/*
+ * Reset the metadata cache.
+ */
+static
+void metadata_cache_reset(struct consumer_metadata_cache *cache)
+{
+       memset(cache->data, 0, cache->cache_alloc_size);
+       cache->max_offset = 0;
+}
+
+/*
+ * Check if the metadata cache version changed.
+ * If it did, reset the metadata cache.
+ * The metadata cache lock MUST be held.
+ *
+ * Returns 0 on success, a negative value on error.
+ */
+static
+int metadata_cache_check_version(struct consumer_metadata_cache *cache,
+               struct lttng_consumer_channel *channel, uint64_t version)
+{
+       int ret = 0;
+
+       if (cache->version == version) {
+               goto end;
+       }
+
+       DBG("Metadata cache version update to %" PRIu64, version);
+       metadata_cache_reset(cache);
+       cache->version = version;
+
+end:
+       return ret;
+}
+
 /*
  * Write metadata to the cache, extend the cache if necessary. We support
  * overlapping updates, but they need to be contiguous. Send the
@@ -79,7 +114,8 @@ end:
  * Return 0 on success, a negative value on error.
  */
 int consumer_metadata_cache_write(struct lttng_consumer_channel *channel,
-               unsigned int offset, unsigned int len, char *data)
+               unsigned int offset, unsigned int len, uint64_t version,
+               char *data)
 {
        int ret = 0;
        int size_ret;
@@ -89,6 +125,12 @@ int consumer_metadata_cache_write(struct lttng_consumer_channel *channel,
        assert(channel->metadata_cache);
 
        cache = channel->metadata_cache;
+
+       ret = metadata_cache_check_version(cache, channel, version);
+       if (ret < 0) {
+               goto end;
+       }
+
        DBG("Writing %u bytes from offset %u in metadata cache", len, offset);
 
        if (offset + len > cache->cache_alloc_size) {