rem: rootfs_unmount(fs_cookie _fs)
add: rootfs_unmount(fs_volume _fs)
context: rootfs_unmount(fs_cookie _fs){	struct rootfs *fs = (struct rootfs *)_fs;	struct rootfs_vnode *v;	struct hash_iterator i;	TRACE(("rootfs_unmount: entry fs = %p\n", fs));	// put_vnode on the root to release the ref to it	vfs_put_vnode(fs->id, fs->root_vnode->id);	// delete all of the vnodes	hash_open(fs->vnode_list_hash, &i);	while((v = (struct rootfs_vnode *)hash_next(fs->vnode_list_hash, &i)) != NULL) {		rootfs_delete_vnode(fs, v, true);	}	hash_close(fs->vnode_list_hash, &i, false);	hash_uninit(fs->vnode_list_hash);	mutex_destroy(&fs->lock);	kfree(fs);	return 0;}