Does XFS ever relocate extents after they are on disk?

[Christoph Hellwig]

On Fri, Mar 11, 2011 at 02:29:30PM -0800, Steven Swanson wrote:
> Christoph,
> 
> Thanks for the quick reply.  
> 
> Here's another question:  If I write data to an extent that already exists, am I also guaranteed that the new data will overwrite the same location?  For instance, will XFS ever relocate an extent on a write in order to expand the extent?

Right now it won't. I wouldn't call that a guaranteed though - e.g. if
we're ever going to finish off storig file data in the inode for small
files we'll have to migrate them out of the inode once we create the
first extent.