- We no longer have to bother with PDIRUNLOCK, lookup() handles it for us.

 - We no longer have to bother with PDIRUNLOCK, lookup() handles it for us.
 - Network filesystems are written with a special idiom that checks the
   cache first, and may even unlock dvp before discovering that a network
   round-trip is required to resolve the name.  I believe dvp is prevented
   from being recycled even in the forced unmount case by the shared lock
   on the mount point.  If not, this code should grow checks for VI_DOOMED
   after it relocks dvp or it will access NULL v_data fields.

Sponsored by:	Isilon Systems, Inc.