anchor.diff:      (check-magic magic)
       (check-feature-incompat feature-incompat)
       (make-superblock :inodes-count (sys.int::ub32ref/le superblock 0)
  -                     :blocks-count (sys.int::ub32ref/le superblock 4)
  -                     :r-blocks-count (sys.int::ub32ref/le superblock 8)
  -                     :free-blocks-count (sys.int::ub32ref/le superblock 12)
  +                     :blocks-count (logior (ash (sys.int::ub32ref/le superblock 336) 64)
  +                                           (sys.int::ub32ref/le superblock 4))
  +                     :r-blocks-count (logior (ash (sys.int::ub32ref/le superblock 340) 64)
  +                                             (sys.int::ub32ref/le superblock 8))
  +                     :free-blocks-count (logior (ash (sys.int::ub32ref/le superblock 344) 64)
  +                                                (sys.int::ub32ref/le superblock 12))
                        :free-inodes-count (sys.int::ub32ref/le superblock 16)
                        :first-data-block (sys.int::ub32ref/le superblock 20)
                        :log-block-size (sys.int::ub32ref/le superblock 24)
  -                     :log-frag-size (sys.int::ub32ref/le superblock 28)
  +                     :log-cluster-size (sys.int::ub32ref/le superblock 28)
                        :blocks-per-group (sys.int::ub32ref/le superblock 32)
  -                     :frags-per-group (sys.int::ub32ref/le superblock 36)
  +                     :clusters-per-group (sys.int::ub32ref/le superblock 36)
                        :inodes-per-group (sys.int::ub32ref/le superblock 40)
                        :mtime (sys.int::ub32ref/le superblock 44)
                        :wtime (sys.int::ub32ref/le superblock 48)
  
positive.code:                                    (sys.int::ub64ref/le superblock 104))
                       :volume-name (map 'string #'code-char (subseq superblock 120 136))
                       :last-mounted (map 'string #'code-char (subseq superblock 136 200))
                       :algo-bitmap (sys.int::ub32ref/le superblock 200)
                       :prealloc-blocks (aref superblock 204)
                       :prealloc-dir-blocks (aref superblock 205)
                       :journal-uuid (logior (ash (sys.int::ub64ref/le superblock 216) 64)
                                             (sys.int::ub64ref/le superblock 208))
                       :journal-inum (sys.int::ub32ref/le superblock 224)
  
negative.code:   (rev-level nil :type (unsigned-byte 32))
    (def-resuid nil :type (unsigned-byte 16))
    (def-resgid nil :type (unsigned-byte 16))
    (first-ino nil :type (unsigned-byte 32))
    (inode-size nil :type (unsigned-byte 16))
    (block-group-nr nil :type (unsigned-byte 16))
  