/*
  * (non-Javadoc)
  *
  * @see
  * org.opendedup.collections.AbstractHashesMap#update(org.opendedup.sdfs
  * .filestore.ChunkData)
  */
 @Override
 public boolean update(ChunkData cm) throws IOException {
   this.arlock.lock();
   try {
     boolean added = false;
     if (!this.isClaimed(cm)) {
       cm.persistData(true);
       added = this.getReadMap(cm.getHash()).update(cm.getHash(), cm.getcPos());
     }
     if (added) {
       this.compactKsz++;
     }
     return added;
   } catch (KeyNotFoundException e) {
     return false;
   } finally {
     this.arlock.unlock();
   }
 }