[tahoe-dev] new mutable file system pushed to trunk

[Brian Warner]

I just pushed about 20 patches for a large-scale overhaul of the way we
handle mutable files. Nothing is changed in the data formats, but the way we
manage test-and-set is completely revamped. This should also fix a number of
issues involving how we tolerate multiple versions in the grid, and lays the
groundwork for more sophisticated applications to see those multiple versions
and do something intelligent with them (perhaps merge them together).

Please give it a try.. there are a lot of unit tests, of course, but I'm not
yet confident about the stability of the new code and would like some extra
eyeballs to shake out the bugs. Note that allmydata/mutable.py has been split
into several smallers files in allmydata/mutable/*.py , and you may
experience problems with stale .pyc files depending upon how you upgrade.

Mutable file operations will probably cost an extra round trip until I turn
on the small cache that I haven't finished testing yet.

cheers,
 -Brian