code: public void extendStore( int blockSize , int oldBlockCount , int newBlockCount ) throws JournalException
      {
          // Refuse any further operation in case of previous failure
          if (failing)
              throw new JournalException("Store journal is failing");
          
          synchronized (journalWriteQueue)
          {
              if (traceEnabled)
                  log.trace("["+baseName+"] #"+currentTransactionId+" Queueing store extend : blockSize="+blockSize+" blockCount="+oldBlockCount+" -> "+newBlockCount+" / queueSize="+(journalWriteQueue.size()+1));
              
              StoreExtendOperation op = new StoreExtendOperation(currentTransactionId,blockSize,oldBlockCount,newBlockCount);
  
              unflushedJournalSize += op.size();
              journalWriteQueue.addLast(op);
              totalPendingOperations++;
          }
      }
docs: Write some store extend operation (asynchronous)