shrinking ubifs?

[Jon Ringle]

On ubi0, I have 3 volumes:
ubi0_0 kernel (static volume)
ubi0_1 squashfs (static volume)
ubi0_2 ubifs (dynamic volume)

When I create the volumes, the static volumes are created first and
then the ubifs volume is created with whatever LEBs are left over. I
am using the squashfs and ubifs in a aufs2 union fs. When I need to
reflash either of the static volumes for an upgrade, and the new
images don't fit the space available in the LEBs reserved in the
corresponding static volume, I remove the ubifs volume to create space
and then recreate the ubifs volume again with what is remaining. This
is sub-optimal as this means that and data on the ubifs is now lost.

Is there a way to shrink a UBIFS if there are unused LEBs in the UBIFS?

Thanks
Jon