[CFT][PATCH] cleanup of partition code

[Alexander Viro]

	Folks, _please_ help to test this one.  It switches most of
the fs/partitions/* to use of pagecache, cleans it up and fixes quite
a few holes in that area.

	It should work in all cases when vanilla tree does.  Please,
try it on different partitioning schemes.

	Things to look for:

* Odd IDE disks - victims of EZ-Disk, OnCrack, etc.
* Minix, Solaris, Unixware partitions.  Changes were completely
  straightforward, but it needs testing.
* BSD disklabels.  Should work, but more testing is needed.
* non-x86 variants - Sun disklables, SGI, etc.  Need testing.

	One thing that doesn't work yet is support of Acorn partitions -
I'm switching it to pagecache right now.

	If there's no bug reports it will go into the tree, so _please_
test it now, not after it's in 2.4.11

	Patch is on ftp.math.psu.edu/pub/viro/partition-a-S11-pre1.  It's
against 2.4.11-pre1.  Again, any help with testing is very welcome.