This patch allows to handle 64-bit block counts.
It introduces new macros to access block counts stored in the superblock.

Changes from the previous version:
remove '_EXT4FS_' conditional compilation and use instead INCOMPAT_64BIT 
tests.

  debugfs/debugfs.c          |    4 +-
  debugfs/logdump.c          |    2 -
  debugfs/lsdel.c            |    2 -
  debugfs/set_fields.c       |    3 +
  debugfs/unused.c           |    2 -
  e2fsck/badblocks.c         |    4 +-
  e2fsck/journal.c           |    4 +-
  e2fsck/pass1.c             |   16 ++++----
  e2fsck/pass2.c             |    4 +-
  e2fsck/pass5.c             |   24 ++++++-------
  e2fsck/super.c             |   22 ++++++------
  e2fsck/unix.c              |   10 ++---
  lib/e2p/ls.c               |    8 ++--
  lib/ext2fs/alloc.c         |    6 +--
  lib/ext2fs/alloc_stats.c   |    2 -
  lib/ext2fs/bb_inode.c      |    2 -
  lib/ext2fs/bitmaps.c       |    4 +-
  lib/ext2fs/block.c         |    6 +--
  lib/ext2fs/bmove.c         |    2 -
  lib/ext2fs/closefs.c       |    2 -
  lib/ext2fs/ext2_fs.h       |   36 ++++++++++++++++++++
  lib/ext2fs/ext2fs.h        |    6 +--
  lib/ext2fs/ext_attr.c      |    2 -
  lib/ext2fs/extent.c        |    4 +-
  lib/ext2fs/initialize.c    |   26 +++++++-------
  lib/ext2fs/openfs.c        |    4 +-
  lib/ext2fs/read_bb.c       |    2 -
  lib/ext2fs/read_bb_file.c  |    2 -
  lib/ext2fs/rw_bitmaps.c    |    2 -
  lib/ext2fs/swapfs.c        |    3 +
  lib/ext2fs/tst_badblocks.c |    2 -
  lib/ext2fs/tst_iscan.c     |    2 -
  misc/e2image.c             |    2 -
  misc/mke2fs.c              |   62 ++++++++++++++++++----------------
  misc/tune2fs.c             |   12 +++---
  misc/util.c                |   12 +++---
  resize/main.c              |    2 -
  resize/online.c            |   11 +++---
  resize/resize2fs.c         |   81 
+++++++++++++++++++++++----------------------
  tests/progs/test_icount.c  |    2 -
  40 files changed, 228 insertions(+), 176 deletions(-)