enlarging a partition

[Pascal GREGIS]

Hi everyone,

I'm using parted-1.6.23 on a Linux from Scratch.

I have the following partitions, with a GPT label :
/       xfs     1.5 GB
/data   xfs     3 GB

I would like to enlarge my /data partition without having to umount it.
I tried with xfs_growfs, but it can only extend the xfs filesystem to the size 
of the partition, which does not help me because my filesystem already occupies 
the whole partition.
I then tried with parted but have 2 problems :
- parted doesn't handle xfs resizing
- parted doesn't want to extend a mounted partition.

In other words, the problem that I have with parted is due to the fact that 
parted doesn't resize a partition, it resizes a partition and the filesystem on 
it. 
I only want to resize the partition, (i.e. just modify the partition table), I 
will extend the filesystem in a second step with xfs_growfs.

How could I do it? Is it possible with parted?
I can upgrade parted to a newer version if necessary.
Or, is it possible via the parted API?

If parted is not the right tool to do it, just tell me, however I've not found 
any other partitionning tool supporting GPT partition tables.

Thanks a lot for your reading

Pascal