code: int collectSubtreeBlocksAndClear(List<BlockInfo> v, 
                                     int blocksLimit, 
                                     List<INode> removedINodes) {
      clearTargets();
      return super.collectSubtreeBlocksAndClear(v, blocksLimit, removedINodes);
    }
docs: When deleting an open file, we should remove it from the list
  of its targets.