Does XFS ever relocate extents after they are on disk?

[Steven Swanson <swanson@xxxxxxxxxxx>]

I have simple question that I'm having trouble finding a concrete answer for:

Does XFS ever relocate a file or one of its extents once it's been written to 
disk?  For instance, does the file system ever decide to reorganize extents to 
reduce fragmentation.

I've read through all the documentation I can find, and everything points to 
using an external de-fragmentation tool, which suggests that XFS won't do it 
autonomously, but for the project we are working on it would be useful to know 
for certain when and under what conditions XFS might decide to move an extent 
that's already been written.

Thanks!

-steve