code: boolean removeBlock(String path, INodeFileUnderConstruction fileNode,
                        Block block) throws IOException {
      waitForReady();
  
      writeLock();
      try {
        // modify file-> block and blocksMap
        fileNode.removeBlock(block);
        getFSNamesystem().blocksMap.removeBlock(block);
        // Remove the block from corruptReplicasMap
        getFSNamesystem().corruptReplicas.removeFromCorruptReplicasMap(block);
  
        // write modified block locations to log
        fsImage.getEditLog().logOpenFile(path, fileNode);
        if (NameNode.stateChangeLog.isDebugEnabled()) {
          NameNode.stateChangeLog.debug("DIR* FSDirectory.removeBlock: "
                                        +path+" with "+block
                                        +" block is removed from the file system");
        }
      } finally {
        writeUnlock();
      }
      return true;
    }
docs: Remove the block from a file.