Function vnode_create_vobject

freebsd/vm/vnode_pager.c:147–188

Create the VM system backing object for this vnode */

/* Create the VM system backing object for this vnode */
int
vnode_create_vobject(struct vnode *vp, off_t isize, struct thread *td)
{
	vm_object_t object;
	vm_ooffset_t size = isize;
	struct vattr va;
	bool last;

	if (!vn_isdisk(vp) && vn_canvmio(vp) == FALSE)
		return (0);

	object = vp->v_object;
	if (object != NULL)
		return (0);

	if (size == 0) {
		if (vn_isdisk(vp)) {
			size = IDX_TO_OFF(INT_MAX);
		} else {
			if (VOP_GETATTR(vp, &va, td->td_ucred))
				return (0);
			size = va.va_size;
		}
	}

	object = vnode_pager_alloc(vp, size, 0, 0, td->td_ucred);
	/*
	 * Dereference the reference we just created.  This assumes
	 * that the object is associated with the vp.  We still have
	 * to serialize with vnode_pager_dealloc() for the last
	 * potential reference.
	 */
	VM_OBJECT_RLOCK(object);
	last = refcount_release(&object->ref_count);
	VM_OBJECT_RUNLOCK(object);
	if (last)
		vrele(vp);

	KASSERT(vp->v_object != NULL, ("vnode_create_vobject: NULL object"));

	return (0);
}

void
vnode_destroy_vobject(struct vnode *vp)