-mount (--one-file-system) like option for rdiff-backup?

[dean gaudet]

ben -- this, plus other features i've been pondering, make me wonder about
external filelist generation for rdiff-backup.

--include-filelist goes some of the way -- but if you include a directory
in --include-filelist then rdiff-backup will recurse.

also -- for some file selection problems you really need access to the
complete file list on both sides of the link.  it seems hard to move this
outside of rdiff-backup.

the problem i run into occasionally is that my users will upload a couple
Gb of data which is a backup of their accounts elsewhere... and they're
sometimes not nice enough to ask me beforehand, or i'd tell them how to
avoid it ending up in my nightly rdiff-backup.

so what i was considering is some sort of "unexpected large delta"
detection prior to transmitting across the link.  the most simple form of
this would be "this 200MB+ file/directory is not yet on the mirror, it
won't be backed up until it's whitelisted somewhere".

i almost asked for a feature like that (and --one-file-system was on my
list early on, but i eventually convinced myself that rdiff-backup of
everything in one hierarchy was best for me).  but i worried that
featuritis in file selection was an indication of a need for a different
design :)

i don't really have an answer... but i keep thinking about multiple
processes sharing data via pipes, so that we could replace some components
with locally modified pieces to get new features.

-dean