When called from vrecycle() or vgone() there is a window where the refcount
is greater than zero and another thread could get and release a reference
that would miss VOP_INACTIVE() as the refcount doesn't drop to zero.
Adjust test fs/puffs/t_basic: test VOP_INACTIVE count being greater zero.
- Make vrecycle() more robust by checking v_usecount first and preventing
further references across vn_lock(). Fixes a deadlock where one thread
starts unmount, second thread locks a directory and allocates a vnode
and first thread tries to vrecycle() the directory.
First thread holds vfs_busy and wants vnode, second thread holds vnode
and wants vfs_busy.
- With these fixes in place change cleanvnode() to use vget()/vrecycle()
to reclaim the vnode.
f3e32599e8