title: after writing a files to an ext4 volume do I need to do more than flush to guarantee the file is fully written?
body: <p>I've written some code where its very important that beyond a certain point that the contents of a file are written to disk </p>
  
  <p>I'm using ext4, such that the volumes integrity is guaranteed with the journal</p>
  
  <p>in order to guarantee my file is actually on disk and not vulnerable to errors replaying the journal in the event of a crash, do I need to do anything more than flush()?   I believe that's it, that the contract of flush is that the contents are on disk, and all buffers/caches are flushed</p>