No subject

>> This information needs to be exported to userland in two different ways:

>> - A simple list of files and directories that have been updated since 
>> the generation requested. This should be suitable for feeding into 
>> rsync.

The way I read that, it's not something rsync-specific.  It sounds like 
btrfs would allow the generation of a list of files, which rsync (or tar, 
or zip, or whatever) could accept.  (Rsync obviously being the best 
choice, :-) )

e.g.:

$ export-whatever-from-btrfs | rsync --files-from=- / backup/

(or)

$ export-whatever-from-btrfs | tar -Jcvf backup.tar.xz -T -
$ export-whatever-from-btrfs | zip -@ backup.zip
...etc...


> Is this someone that is likely to happen in the for see able future?

Sounds like a question for the btrfs folks.

Best,
Ben