How To Resize/Convert a BTRFS-LUKS partition?

[Manuel Escudero]

it's official:

Lately, I've been having a lot of Performance issues because of BTRFS
(Specially when running VM's) so I was wondering if theres a way to Shrink
an encrypted (Crypto-Luks) BTRFS partition in order to create a new Ext4 one
to store my VM's...

In case there's not, I'm interested in knowing how to convert a BTRFS
partition
to Ext4 without loosing any data, the thing is, I want to improve my
experience
with F15 and BTRFS in order to keep the system the way it is now without
having to reinstall,

Can Someone Help?