rem: mount->vnodes_tail = v->mount_prev; if (v->mount_prev) v->mount_prev->mount_next = v->mount_next;
add: mount->vnodes_tail = vnode->mount_prev; if (vnode->mount_prev) vnode->mount_prev->mount_next = vnode->mount_next;
context: remove_vnode_from_mount_list(struct vnode *v, struct fs_mount *mount){	recursive_lock_lock(&mount->rlock);	if (v->mount_next)		v->mount_next->mount_prev = v->mount_prev;	else		mount->vnodes_tail = v->mount_prev;	if (v->mount_prev)		v->mount_prev->mount_next = v->mount_next;	else		mount->vnodes_head = v->mount_next;	v->mount_prev = v->mount_next = NULL;	recursive_lock_unlock(&mount->rlock);}