+ return F_TYPE_EQUAL(sfs.f_type, BTRFS_SUPER_MAGIC);
+}
+
+static int setup_machine_raw(sd_bus_error *error) {
+ _cleanup_free_ char *tmp = NULL;
+ _cleanup_close_ int fd = -1;
+ struct statvfs ss;
+ pid_t pid = 0;
+ siginfo_t si;
+ int r;
+
+ /* We want to be able to make use of btrfs-specific file
+ * system features, in particular subvolumes, reflinks and
+ * quota. Hence, if we detect that /var/lib/machines.raw is
+ * not located on btrfs, let's create a loopback file, place a
+ * btrfs file system into it, and mount it to
+ * /var/lib/machines. */
+
+ fd = open("/var/lib/machines.raw", O_RDWR|O_CLOEXEC|O_NONBLOCK|O_NOCTTY);
+ if (fd >= 0) {
+ r = fd;
+ fd = -1;
+ return r;
+ }
+
+ if (errno != ENOENT)
+ return sd_bus_error_set_errnof(error, errno, "Failed to open /var/lib/machines.raw: %m");
+
+ r = tempfn_xxxxxx("/var/lib/machines.raw", &tmp);
+ if (r < 0)
+ return r;
+
+ (void) mkdir_p_label("/var/lib", 0755);
+ fd = open(tmp, O_RDWR|O_CREAT|O_EXCL|O_NOCTTY|O_CLOEXEC, 0600);
+ if (fd < 0)
+ return sd_bus_error_set_errnof(error, errno, "Failed to create /var/lib/machines.raw: %m");
+
+ if (fstatvfs(fd, &ss) < 0) {
+ r = sd_bus_error_set_errnof(error, errno, "Failed to determine free space on /var/lib/machines.raw: %m");
+ goto fail;
+ }
+
+ if (ss.f_bsize * ss.f_bavail < VAR_LIB_MACHINES_FREE_MIN) {
+ r = sd_bus_error_setf(error, SD_BUS_ERROR_FAILED, "Not enough free disk space to set up /var/lib/machines.");
+ goto fail;
+ }
+
+ if (ftruncate(fd, VAR_LIB_MACHINES_SIZE_START) < 0) {
+ r = sd_bus_error_set_errnof(error, errno, "Failed to enlarge /var/lib/machines.raw: %m");
+ goto fail;
+ }
+
+ pid = fork();
+ if (pid < 0) {
+ r = sd_bus_error_set_errnof(error, errno, "Failed to fork mkfs.btrfs: %m");
+ goto fail;
+ }
+
+ if (pid == 0) {
+
+ /* Child */
+
+ reset_all_signal_handlers();
+ reset_signal_mask();
+ assert_se(prctl(PR_SET_PDEATHSIG, SIGTERM) == 0);
+
+ fd = safe_close(fd);
+
+ execlp("mkfs.btrfs", "-Lvar-lib-machines", tmp, NULL);
+ if (errno == ENOENT)
+ return 99;
+
+ _exit(EXIT_FAILURE);
+ }
+
+ r = wait_for_terminate(pid, &si);
+ if (r < 0) {
+ sd_bus_error_set_errnof(error, r, "Failed to wait for mkfs.btrfs: %m");
+ goto fail;
+ }
+
+ pid = 0;
+
+ if (si.si_code != CLD_EXITED) {
+ r = sd_bus_error_setf(error, SD_BUS_ERROR_FAILED, "mkfs.btrfs died abnormally.");
+ goto fail;
+ }
+ if (si.si_status == 99) {
+ r = sd_bus_error_set_errnof(error, ENOENT, "Cannot set up /var/lib/machines, mkfs.btrfs is missing");
+ goto fail;
+ }
+ if (si.si_status != 0) {
+ r = sd_bus_error_setf(error, SD_BUS_ERROR_FAILED, "mkfs.btrfs failed with error code %i", si.si_status);
+ goto fail;
+ }
+
+ if (renameat2(AT_FDCWD, tmp, AT_FDCWD, "/var/lib/machines.raw", RENAME_NOREPLACE) < 0) {
+ r = sd_bus_error_set_errnof(error, errno, "Failed to move /var/lib/machines.raw into place: %m");
+ goto fail;
+ }
+
+ r = fd;
+ fd = -1;
+
+ return r;
+
+fail:
+ if (tmp)
+ unlink_noerrno(tmp);
+
+ if (pid > 1)
+ kill_and_sigcont(pid, SIGKILL);
+
+ return r;
+}
+
+static int setup_machine_directory(sd_bus_error *error) {
+ struct loop_info64 info = {
+ .lo_flags = LO_FLAGS_AUTOCLEAR,
+ };
+ _cleanup_close_ int fd = -1, control = -1, loop = -1;
+ _cleanup_free_ char* loopdev = NULL;
+ char tmpdir[] = "/tmp/import-mount.XXXXXX", *mntdir = NULL;
+ bool tmpdir_made = false, mntdir_made = false, mntdir_mounted = false;
+ int r, nr = -1;
+
+ r = check_btrfs();
+ if (r < 0)
+ return sd_bus_error_set_errnof(error, r, "Failed to determine whether /var/lib/machines is located on btrfs: %m");
+ if (r > 0) {
+ (void) btrfs_subvol_make_label("/var/lib/machines");
+ return 0;
+ }
+
+ if (path_is_mount_point("/var/lib/machines", true) > 0 ||
+ dir_is_empty("/var/lib/machines") == 0)