code: public void writeMetaData( long metaDataOffset , int metaData ) 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 metadata write : offset="+metaDataOffset+" metaData="+metaData+" / queueSize="+(journalWriteQueue.size()+1));
          	
          	MetaDataWriteOperation op = new MetaDataWriteOperation(currentTransactionId,
  												                   metaDataOffset, 
  												                   metaData);
          	unflushedJournalSize += op.size();
              journalWriteQueue.addLast(op);
              totalPendingOperations++;
          }
      }
docs: Write some metadata value (asynchronous)