+ struct bch_ioctl_dev_usage_v2 *u = xcalloc(sizeof(*u) + sizeof(u->d[0]) * BCH_DATA_NR, 1);
+
+ u->dev = idx;
+ u->flags = BCH_BY_INDEX;
+ u->nr_data_types = BCH_DATA_NR;
+
+ if (!ioctl(fs.ioctl_fd, BCH_IOCTL_DEV_USAGE_V2, u))
+ return u;
+
+ struct bch_ioctl_dev_usage u_v1 = { .dev = idx, .flags = BCH_BY_INDEX};
+ xioctl(fs.ioctl_fd, BCH_IOCTL_DEV_USAGE, &u_v1);