fix for append mode bug (from Rick Macklem)

update from Rick Macklem (including leases)

include ordering

pass proc pointers down to lower levels; use NFS_DIRBLKSIZ

first cut for new proc & user structs (still need to put in new vnode calling
convention): get credentials, etc, via proc; u.u_nd, u.u_spare are gone;

update for new VM

new copyright notice

"update from Rick Macklem"

"nfs_mknod update from Rick Macklem"

"update from Rick Macklem adding TCP support to NFS"

no longer need to munhash, handled by xuntext instead

use bwrite to avoid getting out of sync with it

n_lastr is replaced by v_lastr

v_blockh is split into clean and dirty lists; count active I/O's

"December update from Rick Macklem"

now use b_lblkno in place of b_blkno

brelvp now implied by setting B_INVAL

locking now done above vnode level; read/write no longer take an offp

lint

"bug fixes and cleanups from Rick Macklem"

"update from Rick Macklem"

first buffer cache implementation