dfs_node
dd->dfs_node = debugfs_create_dir(dd->disk->disk_name, dfs_parent);
debugfs_create_file("flags", 0444, dd->dfs_node, dd, &mtip_flags_fops);
debugfs_create_file("registers", 0444, dd->dfs_node, dd,
debugfs_remove_recursive(dd->dfs_node);
struct dentry *dfs_node;