64 bit block pointers, extended attribute storage, and a few
other things.
This commit does not yet include the code to manipulate the extended
storage (for e.g. ACLs), this will be done later.
Originally written by Kirk McKusick and Network Associates Laboratories for
FreeBSD.
(though still not all) errors in a damaged lfs. Segment byte accounting
is corrected in pass 5. "fsck_lfs -p" will do a partial roll-forward,
verifying the checkpoint from the newer superblock. fscknames[] is
updated so that fsck knows about fsck_lfs.