K 10
svn:author
V 3
kib
K 8
svn:date
V 27
2016-09-08T12:04:45.060749Z
K 7
svn:log
V 301
There is no need to upgrade the last dvp lock on lookups for modifying
operations.  Instead of upgrading, assert that the lock is exclusive.
Explain the cause in comments.

This effectively reverts r209367.

Tested by:	pho
Reviewed by:	mckusick
Sponsored by:	The FreeBSD Foundation
MFC after:	2 weeks

END