[linux-lvm] relocate on write for snapshot

[Ming Zhang]

Hi, I wonder if there are any thought about a relocate on write policy
for snapshot instead of copy on write policy used now?

instead of copy old one to snapshot, overwrite old one with new one, 2
writes and 1 reads. it is possible that write new data to a usused
location directly.

i know later remove a snaphot will be a little trouble, but there must
be some way to get around it.

just a rough thought, any comment?

ming