This is a completely rewritten filesystem checker for GFS.  Performance
characteristics are significantly improved.  The design follows the 5-pass
fsck design found in "Fsck - The UNIX File System Check Program"
by McKusick & Kowalkski (1994)
  - http://citeseer.ist.psu.edu/mckusick94fsck.html


Line item list of supported features:

1. Detects and replaces missing/bad root inode
2. Detects and relinks unlinked inodes to l+f
   o If a file is zero length, it is not relinked to l+f - unless it
     has an extended attribute attached to it.
3. Detects duplicate blocks and removes inodes containing them
4. Detects bad blocks (block number out of range) and removes inodes
   containing them - Currently EAs that have blocks are removed but
   the inode containing them is left.
5. Detects bad metadata headers and clears the structure
6. Fixes bad resource group bitmaps
7. Fixes incorrect resource group counts
8. Creates l+f directory if missing
9. Detects and removes duplicate '.' and '..' entries
10. Creates '.' if missing
11. Beginning of support for internationalization
12. Checks extended attributes
