bandaid to avoid unlock panic until we do it right;
trivia: this was the final delta done by CSRG

allow opening for reading and writing (from mycroft)

read-only checking must be done by the filesystem layers

add in proper layer locking

add proper locking

add proper locking and lookup routines; document other needed actions

have to have fifo_inactive so can unlock at its end

follow proper locking protocol

have to follow locking protocol in kernfs_lookup

inactive routine must unlock node

inactive becomes real

inactive routine must unlock node

inactive routine must unlock node

inactive routine must unlock node

fifo_inactive becomes real

inactive routine must unlock node

cleanups (from mycroft)

new locking

VOP_UNLOCK vrele -> vput

lock vnode while computing dircache

new mount locking protocol

convert VOP_LOCK to vn_lock; add parameters to VOP_UNLOCK and vget

convert VOP_LOCK to vn_lock; add parameters to VOP_UNLOCK and vget

add umap_lock to check VXLOCK and clear interlock before bypassing

convert VOP_LOCK to vn_lock; add parameters to VOP_UNLOCK and vget
locking functions no longer needed (use vop_nolock* instead)