merge everything from chs-ubc branch.
Sync w/ -current.
Sync w/ -current.
Chuq apparently forgot to place this on the ubc2 branch.
Sync w/ -current (again) to get a typo fix.
Correct a printf format now that vnode flags are an int (in the uvm_vnode
structure).
Forward decl struct csum.
Pull in ffs_extern.h to get ffs_balloc_range() prototype for
ufs_readwrite.c
Fix a merge error.
Make this compile in the face of some UVM interface changes, and kill
void * arithmetic.
Add vfs_cluster.c again, so that GENERIC at least compiles.
Put back the calls to cluster_*(), but #if 0 them out.  This is mostly
for use as a reference point.
Sync w/ -current.
Fix merge botch.
Oops, fix botch in previous.
Fix merge botch.
Remove the VREG panic from getblk() so that file systems which have not
yet been converted to use UBC continue to work with the old buffer cache.
Remove an #ifdef UBC for the new uvm_vnode/vnode flags; just always use them
instead, and g/c the old ones.  (Boy, this really confused me at first! :-)
Add UBC glue to sys_fhopen() (because it has some vn_open() stuff inline).
Take two at making a non-converted LFS work in a UBC kernel.