code: public void writeMetaDataBlock( long metaDataOffset , byte[] 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 block write : offset="+metaDataOffset+" size="+metaData.length+" / queueSize="+(journalWriteQueue.size()+1));
          	
          	MetaDataBlockWriteOperation op = 
          		new MetaDataBlockWriteOperation(currentTransactionId,
  							                    metaDataOffset, 
  							                    metaData);
              journalWriteQueue.addLast(op);
              unflushedJournalSize += op.size();
              totalPendingOperations++;
          }
      }
docs: Write some metadata block (asynchronous)