code: private void processFailedBlocks(Block []failed, 
        int failedPendingRequests) {
      synchronized (receivedAndDeletedBlockList) {
        // We are adding to the front of a linked list and hence to preserve
        // order we should add the blocks in the reverse order.
        for (int i = failed.length - 1; i >= 0; i--) {
          receivedAndDeletedBlockList.add(0, failed[i]);
        }
        pendingReceivedRequests += failedPendingRequests;
      }
    }
docs: Adds blocks of incremental block report back to the
  receivedAndDeletedBlockList, when handling an exception
  
  @param failed - list of blocks
  @param failedPendingRequests - how many of the blocks are received acks.