title: How to "defragment" a directory on ext3?
body: <p>I am running a daemon which analyses files in a directory and then deletes them. In case the daemon is not running for whatever reason, files get stacked there. Today I had 90k files in that directory. After starting the daemon again, it processed all the files.</p>
  
  <p>However, the directory remains large; "ls -dh ." returns a size of 5.6M. How can I "defragment" that directory? I already figured out that renaming that directory, and creaing a new one with the same name and permissions solves the problem. However, as files get written in there at any time, there doesn't seem to be a safe way to rename the directory and create a new one as for a moment, the target directory does not exist.</p>
  
  <p>So a) is there a way/a (shell) program which can defragment directories on an ext3 filesystem? or b) is there a way to create a lock on a directory so that trying to write files blocks until the rename/create has finished?</p>