// leveldir_current may be invalid (level group, parent link)
if (!validLevelSeries(leveldir_current))
leveldir_current = getFirstValidTreeInfoEntry(leveldir_last_valid);
// leveldir_current may be invalid (level group, parent link)
if (!validLevelSeries(leveldir_current))
leveldir_current = getFirstValidTreeInfoEntry(leveldir_last_valid);