I was browsing through the latest literature on Btrfs and discovered this little gem:
https://en.wikipedia.org/wiki/Btrfs
So, the idea is that a distro developer could create a LiveCD installer that has a read-only Btrfs "seed" (not sure what they entails) on an OPTICAL disc. The user could then use the KParted app to modify a partition, say sd1, and then balance itself to that partition, all while allowing the user to continue working. Ejecting the LiveCD when balancing is done allows the user to continue working on the rw Btrfs sda1 partition WITHOUT rebooting.
I LIKE THAT!
https://en.wikipedia.org/wiki/Btrfs
Union mounting / seed devices
When creating a new Btrfs, an existing Btrfs can be used as a read-only "seed" file system.[69] The new file system will then act as a copy-on-write overlay on the seed, as a form of union mounting. The seed can be later detached from the Btrfs, at which point the balance command will simply copy over any seed data still referenced by the new file system before detaching. Mason has suggested this may be useful for a Live CD installer, which might boot from a read-only Btrfs seed on an optical disc, rebalance itself to the target partition on the install disk in the background while the user continues to work, then eject the disc to complete the installation without rebooting.
When creating a new Btrfs, an existing Btrfs can be used as a read-only "seed" file system.[69] The new file system will then act as a copy-on-write overlay on the seed, as a form of union mounting. The seed can be later detached from the Btrfs, at which point the balance command will simply copy over any seed data still referenced by the new file system before detaching. Mason has suggested this may be useful for a Live CD installer, which might boot from a read-only Btrfs seed on an optical disc, rebalance itself to the target partition on the install disk in the background while the user continues to work, then eject the disc to complete the installation without rebooting.
I LIKE THAT!