[linux-lvm] question about extending snapshots

[Brian Chrisman]

I'm running rhel6.2 nearly stock.
When I mount a snapshot (writable) and perform an lvextend, the CoW
table increases in size, but the logical volume size (for example,
blockdev output) doesn't change itself.
Is this impossible because the regions of the snapshot volume wouldn't
have any corresponding regions in the origin volume?
Is there any way to change the size reported by a snapshot?

What I'm trying to do is take a snapshot, mount it, do stuff to it,
and if I need, make it bigger, and if I need to, just drop it and
create a new one.
If I just take a snapshot and modify the origin and use a merge, then
space becomes an issue.

thanks,
Brian