D22: every restore puts the data back exactly on failure and after a power cut (R-1177, R-1195); whole restore asks the unit first (R-1178); no mirror during a restore (R-1180); W22 restore refusals in Hungarian; unreleased

controller/internal/backup/offbox_restore_undo.go

@@ -134,6 +134,15 @@ func (m *Manager) planLiveVolumeCopy(vols []string) (need int64, exists map[stri
 // copyLiveVolumes tars every existing volume of the plan into a fresh restoreUndoDir. Runs with the app
 // STOPPED, so each copy is consistent. On any error the partial copy is removed and nothing has moved yet.
 func (m *Manager) copyLiveVolumes(stack, nsRoot string, vols []string, exists map[string]bool) (*liveVolumeCopy, error) {
+	// D22: when none of the volumes exists there is nothing to copy — the copy is the list of volumes the backup adds
+	// (removed on a put-back), with no folder.
+	none := true
+	for _, v := range vols {
+		none = none && !exists[v]
+	}
+	if none {
+		return &liveVolumeCopy{absent: append([]string(nil), vols...)}, nil
+	}
 	dir := filepath.Join(restoreUndoDir(nsRoot, stack), time.Now().UTC().Format("20060102T150405Z"))
 	if err := os.MkdirAll(dir, 0o700); err != nil {
 		return nil, err