sys/kern/vfs_vnops.c

1642 vn_start_write(struct vnode *vp, struct mount **mpp, int flags)
1647 	KASSERT((flags & V_MNTREF) == 0 || (*mpp != NULL && vp == NULL),
1656 		if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) {
1657 			*mpp = NULL;
1663 	if ((mp = *mpp) == NULL)
1694 vn_start_secondary_write(struct vnode *vp, struct mount **mpp, int flags)
1699 	KASSERT((flags & V_MNTREF) == 0 || (*mpp != NULL && vp == NULL),
1704 		if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) {
1705 			*mpp = NULL;
1715 	if ((mp = *mpp) == NULL)