Add a (name,vnode) entry to the VFS namecache.
- macOS 10.4+
Directory in which file lives.
File to add to cache. A non-NULL vp is stored for rapid access; a NULL vp indicates that there is no such file in the directory and speeds future failed lookups.
Various data about lookup, e.g. filename and intended operation.
Generally used to add a cache entry after a successful filesystem-level lookup or to add a negative entry after one which did not find its target.