* Add lfs_balloc capability to the lfs library.
* Extend the Ifile if we run out of free inodes when creating lost+found.
* Don't roll forward if we have allocated a lost+found, to avoid
conflicts when adding new files in roll-forward.
* Make some messages slightly more verbose (e.g. include inode number,
and use pwarn() instead of printf() so the messages include the device
name when preening).
* Change superblock detection/avoidance to use the offset table in the
primary superblock, rather than looking at the contents.
* Be more verbose about various operations when passed the -d flag,
especially roll-forward.
* Be more careful about dirops during roll forward, since the cleaner can
sometimes write blocks from dirop vnodes. Detect and avoid this problem.
* Always check the free list, even if given -i; if we're going to write
it we have to check it first.
* Mark inodes dirty when blocks are found during roll forward, so the
inodes are written with the new block locations.
* Update size of inodes if blocks beyond EOF are found during roll
forward.
* Fix segment accounting for blocks and inodes found during roll
forward.
* Report statistics on roll forward: how many new/deleted/moved files
and how many updated blocks (or "nothing new").
* Don't care if the device being checked is really a device, if we have
been passed the -f flag (to facilitate automated testing).
* When writing to the disk, use the current time in the segment headers
rathern than time 0.
* When passed the -i flag, locate the partial segment containing the
Ifile inode and use that to calculate lfs_offset, lfs_curseg,
lfs_nextseg. (Again for automated testing.)
