5045 use atomic_{inc,dec}_* instead of atomic_add_*
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Garrett D'Amore <garrett@damore.org>
Approved by: Robert Mustacchi <rm@joyent.com>

6671591 lofs needs to propagate vfs features from real vfs

PSARC 2006/270 vfs_femhead change to vfs_implp
6418270 RFE: Need implementation private data for vfs
6419029 sys/vnode.h pollutes the userland namespace

5034470 Fix for bug 4126922 is incomplete, still lofs stack overflow panic possible

OpenSolaris Launch