Previously, we were setting bits up to the first byte boundary,
memset()ing to the last byte boundary, then ignoring the memset()
and resetting every single bit up to the last one individually,
from where the first for-loop left off.
This should be *at least* nine times faster.
server startup (sparse write avoidance doesn't happen until it is finished).
Added mutex to bitset functions, which were already being called from
multiple threads. Rewrote allocation map builder to request file
information in multiple chunks, to avoid uninterruptible wait and dynamic
memory allocation.
If you compile with:
DEBUG=true rake build
then all the commands get a --debug flag as an option which will make
the server dump crazy amounts of data to stderr.
