code: void persistBlocks(String path, INodeFileUnderConstruction file)
                       throws IOException {
      waitForReady();
  
      writeLock();
      try {
        fsImage.getEditLog().logOpenFile(path, file);
        if (NameNode.stateChangeLog.isDebugEnabled()) {
          NameNode.stateChangeLog.debug("DIR* FSDirectory.persistBlocks: "
                                        +path+" with "+ file.getBlocks().length
                                        +" blocks is persisted to the file system");
        }
      } finally {
        writeUnlock();
      }
    }
docs: Persist the block list for the inode.