reiserfs: tidy up super block printing, switch reiserfs proc code to use bdevname instead of __bdevname.

  reiserfs: use reiserfs_bdevname(s) instead of s->s_id. From Josh MacDonald.

Make the 144 files in fs/ that need it include buffer_head.h directly.
Again some uses in the VFS files are layering violations and need to
be addressed later.  The new include statement gives a nice grep pattern
for that :)

[ I reversed the order in which writeback walks the superblock's
  dirty inodes.  It sped up dbench's unlink phase greatly.  I'm
  such a sleaze ]

The core writeback patch.  Switches file writeback from the dirty
buffer LRU over to address_space.dirty_pages.

- The buffer LRU is removed

- The buffer hash is removed (uses blockdev pagecache lookups)

- The bdflush and kupdate functions are implemented against
  address_spaces, via pdflush.

- The relationship between pages and buffers is changed.

  - If a page has dirty buffers, it is marked dirty
  - If a page is marked dirty, it *may* have dirty buffers.
  - A dirty page may be "partially dirty".  block_write_full_page
    discovers this.

- A bunch of consistency checks of the form

	if (!something_which_should_be_true())
		buffer_error();

  have been introduced.  These fog the code up but are important for
  ensuring that the new buffer/page code is working correctly.

- New locking (inode.i_bufferlist_lock) is introduced for exclusion
  from try_to_free_buffers().  This is needed because set_page_dirty
  is called under spinlock, so it cannot lock the page.  But it
  needs access to page->buffers to set them all dirty.

  i_bufferlist_lock is also used to protect inode.i_dirty_buffers.

- fs/inode.c has been split: all the code related to file data writeback
  has been moved into fs/fs-writeback.c

- Code related to file data writeback at the address_space level is in
  the new mm/page-writeback.c

- try_to_free_buffers() is now non-blocking

- Switches vmscan.c over to understand that all pages with dirty data
  are now marked dirty.

- Introduces a new a_op for VM writeback:

	->vm_writeback(struct page *page, int *nr_to_write)

  this is a bit half-baked at present.  The intent is that the address_space
  is given the opportunity to perform clustered writeback.  To allow it to
  opportunistically write out disk-contiguous dirty data which may be in other zones.
  To allow delayed-allocate filesystems to get good disk layout.

- Added address_space.io_pages.  Pages which are being prepared for
  writeback.  This is here for two reasons:

  1: It will be needed later, when BIOs are assembled direct
     against pagecache, bypassing the buffer layer.  It avoids a
     deadlock which would occur if someone moved the page back onto the
     dirty_pages list after it was added to the BIO, but before it was
     submitted.  (hmm.  This may not be a problem with PG_writeback logic).

  2: Avoids a livelock which would occur if some other thread is continually
     redirtying pages.

- There are two known performance problems in this code:

  1: Pages which are locked for writeback cause undesirable
     blocking when they are being overwritten.  A patch which leaves
     pages unlocked during writeback comes later in the series.

  2: While inodes are under writeback, they are locked.  This
     causes namespace lookups against the file to get unnecessarily
     blocked in wait_on_inode().  This is a fairly minor problem.

     I don't have a fix for this at present - I'll fix this when I
     attach dirty address_spaces direct to super_blocks.

- The patch vastly increases the amount of dirty data which the
  kernel permits highmem machines to maintain.  This is because the
  balancing decisions are made against the amount of memory in the
  machine, not against the amount of buffercache-allocatable memory.

  This may be very wrong, although it works fine for me (2.5 gigs).

  We can trivially go back to the old-style throttling with
  s/nr_free_pagecache_pages/nr_free_buffer_pages/ in
  balance_dirty_pages().  But better would be to allow blockdev
  mappings to use highmem (I'm thinking about this one, slowly).  And
  to move writer-throttling and writeback decisions into the VM (modulo
  the file-overwriting problem).

- Drops 24 bytes from struct buffer_head.  More to come.

- There's some gunk like super_block.flags:MS_FLUSHING which needs to
  be killed.  Need a better way of providing collision avoidance
  between pdflush threads, to prevent more than one pdflush thread
  working a disk at the same time.

  The correct way to do that is to put a flag in the request queue to
  say "there's a pdlfush thread working this disk".  This is easy to
  do: just generalise the "ra_pages" pointer to point at a struct which
  includes ra_pages and the new collision-avoidance flag.

 - bdevname() switched to struct block_device *.  Old variant (taking
   kdev_t) renamed to __bdevname() (very few callers remain).  This
   allow to drop ->b_dev conveniently - it's duplicated by ->b_bdev
   and most of remaining users were bdevname(bh->b_dev) in various
   places.

Original from: Brian Gerst <bgerst@didntduck.org>
Has had a once over by Chris Mason and Al.

Seperates reiserfs_sb_info from struct super_block.

						Brian Gerst

   Correctly detect and print hash values, when manual hash detection is used.

Big bits first, I'll redo the smaller bits tomorrow after some sleep.
Same as last time, rediffed against pre5

- Doug Ledford: i810 audio driver update
- Evgeniy Polyakov: update various SCSI drivers to new locking
- David Howells: syscall latency improvement, try 2
- Francois Romieu: dscc4 driver update
- Patrick Mochel: driver model fixes
- Andrew Morton: clean up a few details in ext3 inode initialization
- Pete Wyckoff: make x86 machine check print out right address..
- Hans Reiser: reiserfs update
- Richard Gooch: devfs update
- Greg KH: USB updates
- Dave Jones: PNPBIOS
- Nathan Scott: extended attributes
- Corey Minyard: clean up zlib duplication (triplication..)

- Greg KH: USB updates
- various: kdev_t updates
- Al Viro: more bread()/filesystem cleanups

  - Ivan Kokshaysky: fix alpha dec_and_lock with modules, for alpha config entry
  - Kai Germaschewski: ISDN updates
  - Jeff Garzik: network driver updates, sysv fs update
  - Kai Mäkisara: SCSI tape update
  - Alan Cox: large drivers merge
  - Nikita Danilov: reiserfs procfs information
  - Andrew Morton: ext3 merge
  - Christoph Hellwig: vxfs livelock fix
  - Trond Myklebust: NFS updates
  - Jens Axboe: cpqarray + cciss dequeue fix
  - Tim Waugh: parport_serial base_baud setting
  - Matthew Dharm: usb-storage Freecom driver fixes
  - Dave McCracken: wait4() thread group race fix

  - me: remember to bump the version number ;)
  - Hugh Dickins: export "free_lru_page()" for modules
  - Jeff Garzik: don't change nopage arguments, just make the last a dummy one
  - David Miller: sparc and net updates (netfilter, VLAN etc)
  - Nikita Danilov: reiserfs cleanups
  - Jan Kara: quota initialization race
  - Tigran Aivazian: make the x86 microcode update driver happy about
  hyperthreaded P4's
  - me: shrink dcache/icache more aggressively
  - me: fix up oom-killer so that it actually works

  - Jens Axboe: clean up duplicate unused request list
  - Jeff Mahoney: reiserfs endianness finishing touches
  - Hugh Dickins: some further swapoff fixes and cleanups
  - prepare-for-Alan: move drivers/i2o into drivers/message/i2o
  - Leonard Zubkoff: 2TB disk device fixes
  - Paul Schroeder: mwave config enable
  - Urban Widmark: fix via-rhine double free..
  - Tom Rini: PPC fixes
  - NIIBE Yutaka: SuperH update

  - Alan Cox: more merging
  - Ben Fennema: UDF module license
  - Jeff Mahoney: reiserfs endian safeness
  - Chris Mason: reiserfs O_SYNC/fsync performance improvements
  - Jean Tourrilhes: wireless extension update
  - Joerg Reuter: AX.25 updates
  - David Miller: 64-bit DMA interfaces

  - Jens Axboe: remove trivially dead io_request_lock usage
  - Andrea Arcangeli: softirq cleanup and ARM fixes. Slab cleanups
  - Christoph Hellwig: gendisk handling helper functions/cleanups
  - Nikita Danilov: reiserfs dead code pruning
  - Anton Altaparmakov: NTFS update to 1.1.18
  - firestream network driver: patch reverted on authors request
  - NIIBE Yutaka: SH architecture update
  - Paul Mackerras: PPC cleanups, PPC8xx update.
  - me: reverse broken bootdata allocation patch that went into pre5

  - Al Viro: sanity-check user arguments, zero-terminated strings etc.
  - Urban Widmark: smbfs update (server/client cache coherency etc)
  - Rik van Riel, Marcelo Tosatti: VM updates
  - Cort Dougan: PPC updates
  - Neil Brown: raid1/5 failed drive fixups, NULL ptr checking, md error cleanup
  - Neil Brown: knfsd fix for 64-bit architectures, and filehandle resolveir
  - Ken Brownfield: workaround for menuconfig CPU selection glitch
  - David Miller: sparc64 MM setup fix, arpfilter forward port
  - Keith Owens: Remove obsolete IPv6 provider based addressing
  - Jari Ruusu: block_write error case cleanup fix
  - Jeff Garzik: netdriver update

  - David Miller: sparc rw semaphores moved over
  - Alan Cox: yet more resyncs
  - NIIBE Yutaka: Super-H driver update
  - David Howells: more rw-sem cleanups, updates
  - USB updates
  - Al Viro: filesystem init cleanup

  - ppp UP deadlock attack fix

  - ReiserFS merge
  - fix DRM R128/AGP dependency