K 10
svn:author
V 3
kan
K 8
svn:date
V 27
2009-04-12T19:41:16.579116Z
K 7
svn:log
V 546
MFC changes 190533 and 190945:

Replace v_dd vnode pointer with v_cache_dd pointer to struct namecache
in directory vnodes. Allow namecache dotdot entry to be created pointing
from child vnode to parent vnode if no existing links in opposite
direction exist. Use direct link from parent to child for dotdot lookups
otherwise.

This restores more efficient dotdot caching in NFS filesystems which
was lost when vnodes stoppped being type stable.

Majority of backporting work for this was done by jhb.

Reviewed by:	jhb, kib
Approved by:	re (kib)

END