Re: [PATCH] Btrfs: remove duplicated btrfs_release_path in btrfs_unlink_subvol

[Liu Bo]

On Tue, Aug 14, 2018 at 12:46:00PM +0200, David Sterba wrote:
> On Tue, Aug 14, 2018 at 10:47:09AM +0800, Liu Bo wrote:
> > The btrfs_release_path() is just useless as path is only used in error 
> > handling.
> 
> Where is it duplicated? And I don't think it's useless, while the
> changelog does not explain why and it's not obvious from the context. If
> the path is locked, then releasing it right after it's not needed makes
> sense.  There are several potentially heavyweight operations between the
> release and final free.

I see, the diff context is a little bit misleading, the logic in
btrfs_unlink_subvol() is like,

{
        ...
        btrfs_delete_one_dir_name(path);
        btrfs_release_path(path);

        ret = btrfs_del_root_ref(); <<<< path is not used here.
        if (ret < 0) {
                btrfs_search_dir_index_item(path);
                btrfs_release_path(path);
        }
        btrfs_release_path(path);   <<<< path has been released anyway.
        ...
}

thanks,
-liubo