title: the linux page cache flush order
body: <p>There is page cache before we write data to disk.</p>
  
  <p>So if I have two operations.</p>
  
  <pre><code>write(fileA)
  write(fileB)
  </code></pre>
  
  <p>Then if the system is suddenly shutdown. <strong>We don't initiative call the sync() call.</strong></p>
  
  <p>I want to know if it is possible that the data we wrote to fileB has flush to the disk, while the data we wrote to fileA haven't been flush to the disk?</p>