index_config
.memory_size = geometry.index_config.mem,
.sparse = geometry.index_config.sparse,
geometry->index_config = (struct index_config) {
struct index_config index_config;
struct index_config index_config;
static void write_index_config(struct index_config *config, char **buf,
write_index_config(&vdo->geometry.index_config, buf, maxlen);