+
+struct log_header {
+ char magic[4];
+ uint32_t size;
+ BlueSkyCloudID id;
+ uint32_t pointer_count;
+} __attribute__((packed));
+
+struct logref {
+ BlueSkyCloudID id;
+ BlueSkyCloudPointer location;
+} __attribute__((packed));
+
+struct log_footer {
+ char refmagic[4];
+ struct logref refs[0];
+};
+
+/* Ensure that a cloud log item is loaded in memory, and if not read it in.
+ * TODO: Make asynchronous, and make this also fetch from the cloud. Right now
+ * we only read from the log. Log item must be locked. */
+void bluesky_cloudlog_fetch(BlueSkyCloudLog *log)
+{
+ if (log->data != NULL)
+ return;
+
+ if ((log->location_flags | log->pending_write) & CLOUDLOG_JOURNAL) {
+ bluesky_cloudlog_stats_update(log, -1);
+ log->data = bluesky_log_map_object(log->fs, -1, log->log_seq,
+ log->log_offset, log->log_size);
+ bluesky_cloudlog_stats_update(log, 1);
+ }
+
+ if (log->data == NULL && (log->location_flags & CLOUDLOG_CLOUD)) {
+ log->location_flags &= ~CLOUDLOG_JOURNAL;
+ bluesky_cloudlog_stats_update(log, -1);
+ log->data = bluesky_log_map_object(log->fs, log->location.directory,
+ log->location.sequence,
+ log->location.offset,
+ log->location.size);
+ bluesky_cloudlog_stats_update(log, 1);
+ }
+
+ if (log->data == NULL) {
+ g_error("Unable to fetch cloudlog entry!");
+ }
+
+ g_cond_broadcast(log->cond);
+}
+
+BlueSkyCloudPointer bluesky_cloudlog_serialize(BlueSkyCloudLog *log,
+ BlueSkyFS *fs)
+{
+ BlueSkyCloudLogState *state = fs->log_state;
+
+ if ((log->location_flags | log->pending_write) & CLOUDLOG_CLOUD) {
+ return log->location;
+ }
+
+ for (int i = 0; i < log->links->len; i++) {
+ BlueSkyCloudLog *ref = g_array_index(log->links,
+ BlueSkyCloudLog *, i);
+ if (ref != NULL)
+ bluesky_cloudlog_serialize(ref, fs);
+ }
+
+ g_mutex_lock(log->lock);
+ bluesky_cloudlog_fetch(log);
+ g_assert(log->data != NULL);
+
+ bluesky_cloudlog_stats_update(log, -1);
+
+ /* TODO: Right now offset/size are set to the raw data, but we should add
+ * header parsing to the code which loads objects back in. */
+ log->location = state->location;
+ log->location.offset = state->data->len + sizeof(struct log_header);
+ log->location.size = log->data->len;
+ /* = sizeof(struct log_header) + sizeof(BlueSkyCloudID) * 0
+ + log->data->len; */
+
+ struct log_header header;
+ memcpy(header.magic, "AgI ", 4);
+ header.size = GUINT32_TO_LE(log->location.size);
+ header.id = log->id;
+ header.pointer_count = GUINT32_TO_LE(0);
+
+ g_string_append_len(state->data, (const char *)&header, sizeof(header));
+ g_string_append_len(state->data, log->data->data, log->data->len);
+
+ /* If the object we flushed was an inode, update the inode map. */
+ if (log->type == LOGTYPE_INODE) {
+ g_mutex_lock(fs->lock);
+ InodeMapEntry *entry = bluesky_inode_map_lookup(fs->inode_map,
+ log->inum, 1);
+ entry->id = log->id;
+ entry->location = log->location;
+ g_mutex_unlock(fs->lock);
+ }
+
+ /* TODO: We should mark the objects as committed on the cloud until the
+ * data is flushed and acknowledged. */
+ log->pending_write |= CLOUDLOG_CLOUD;
+ bluesky_cloudlog_stats_update(log, 1);
+ state->writeback_list = g_slist_prepend(state->writeback_list, log);
+ bluesky_cloudlog_ref(log);
+ g_mutex_unlock(log->lock);
+
+ if (state->data->len > CLOUDLOG_SEGMENT_SIZE)
+ bluesky_cloudlog_flush(fs);
+
+ return log->location;
+}
+
+static void cloudlog_flush_complete(BlueSkyStoreAsync *async,
+ SerializedRecord *record)
+{
+ g_print("Write of %s to cloud complete, status = %d\n",
+ async->key, async->result);
+
+ g_mutex_lock(record->lock);
+ if (async->result >= 0) {
+ while (record->items != NULL) {
+ BlueSkyCloudLog *item = (BlueSkyCloudLog *)record->items->data;
+ g_mutex_lock(item->lock);
+ bluesky_cloudlog_stats_update(item, -1);
+ item->pending_write &= ~CLOUDLOG_CLOUD;
+ item->location_flags |= CLOUDLOG_CLOUD;
+ bluesky_cloudlog_stats_update(item, 1);
+ g_mutex_unlock(item->lock);
+ bluesky_cloudlog_unref(item);
+
+ record->items = g_slist_delete_link(record->items, record->items);
+ }
+
+ bluesky_string_unref(record->data);
+ record->data = NULL;
+ g_slist_free(record->items);
+ record->items = NULL;
+ record->complete = TRUE;
+ g_cond_broadcast(record->cond);
+ } else {
+ g_print("Write should be resubmitted...\n");
+
+ BlueSkyStoreAsync *async2 = bluesky_store_async_new(async->store);
+ async2->op = STORE_OP_PUT;
+ async2->key = g_strdup(async->key);
+ async2->data = record->data;
+ bluesky_string_ref(record->data);
+ bluesky_store_async_submit(async2);
+ bluesky_store_async_add_notifier(async2,
+ (GFunc)cloudlog_flush_complete,
+ record);
+ bluesky_store_async_unref(async2);
+ }
+ g_mutex_unlock(record->lock);
+}
+
+/* Finish up a partially-written cloud log segment and flush it to storage. */
+void bluesky_cloudlog_flush(BlueSkyFS *fs)
+{
+ BlueSkyCloudLogState *state = fs->log_state;
+ if (state->data == NULL || state->data->len == 0)
+ return;
+
+ /* TODO: Append some type of commit record to the log segment? */
+
+ g_print("Serializing %zd bytes of data to cloud\n", state->data->len);
+ SerializedRecord *record = g_new0(SerializedRecord, 1);
+ record->data = bluesky_string_new_from_gstring(state->data);
+ record->items = state->writeback_list;
+ record->lock = g_mutex_new();
+ record->cond = g_cond_new();
+ state->writeback_list = NULL;
+
+ BlueSkyStoreAsync *async = bluesky_store_async_new(fs->store);
+ async->op = STORE_OP_PUT;
+ async->key = g_strdup_printf("log-%08d-%08d",
+ state->location.directory,
+ state->location.sequence);
+ async->data = record->data;
+ bluesky_string_ref(record->data);
+ bluesky_store_async_submit(async);
+ bluesky_store_async_add_notifier(async,
+ (GFunc)cloudlog_flush_complete,
+ record);
+ bluesky_store_async_unref(async);
+
+ state->pending_segments = g_list_prepend(state->pending_segments, record);
+
+ state->location.sequence++;
+ state->location.offset = 0;
+ state->data = g_string_new("");
+}