label problem

[Robert J. Carr]

This isn't a bug, per se, but I couldn't find a user forum so if this
is the wrong place, please let me know.

I used parted to create a large partition, about 4TB.  It worked fine,
but I forgot to set the partition type, or label, so it defaulted to
msdos.  I then formatted the partition with xfs and everything was
working fine, until I restarted.

After the restart the partition shrunk itself back down to 2TB ...
this is because it is a msdos partition that doesn't support > 2TB.
[NOTE TO DEVS: Can you change the code so it doesn't allow you to
create a > 2TB partition on an msdos type?]  I've searched google and
have a couple hits of this happening the before, here's an example:

http://www.nabble.com/Truncated-Filesystem-tf4537095.html#a12949444

I now know what I did wrong and I've correctly set up another 4TB
partition on another channel.  But the 4TB that got screwed up is
important data, and I'd like to get it back.

My initial thought was to use parted to resize the partition.
Unfortunately, the filesystem is xfs, and when trying to resize a test
partition I got this:

"Support for opening xfs file systems is not supported yet."

So I guess my main question is ... why did this work in the first
place.  I was allowed to create a 4TB partition of msdos type, and I
filled it up with 3TB of data.  But after a restart, it magically
doesn't work.  Is there anything I can do to trick it into working?
Any other suggestions?

I'm open to anything ... please advise, and thanks!

Regards-
Robert