VOP_LOCK(9) on FreeBSD

The text 8b448c1d1cf0, as FreeBSD 4.3-RELEASE, FreeBSD 4.2-RELEASE, FreeBSD 4.1.1-RELEASE, FreeBSD 4.1-RELEASE, FreeBSD 4.0-RELEASE shipped it.

serialize access to a vnode

VOP_LOCK(9) on FreeBSD now