ext3 no longer keeps the filesystem-wide free blocks counter and free inodes
counter up to date all the time in the superblock.  Because that requires
fs-wide locking.  These counters are only needed at runtime for the Orlov
allocator heuristics, and we are now using a fuzzy per-cpu coutner for that.

These counters are rather unnecessary: the same info is present in the file
allocation maps and inode tables, the group descriptor blocks and the
bitmaps.

e2fsck will be changed to downgrade the seriousness of this inconsistency.

The filesystem _will_ write these numbers out in the superblock on a clean
unmount, based on the sum of the free block and inode counts in the group
descriptors.