Re: [PATCH] 9p: don't use v9fs_parent_fid() when v9fs_fid_clone() is needed

[Al Viro]

On Mon, Aug 01, 2016 at 09:57:17PM +0200, Johannes Berg wrote:
> The introduction of v9fs_parent_fid() broke v9fs_vfs_rename()
> since that doesn't just do v9fs_fid_lookup() but rather uses
> v9fs_fid_clone() on the ->d_parent.
> 
> I suppose it'd be possible to introduce v9fs_clone_parent_fid()
> but I decided that just reverting the broken change was better
> for now.

Sorry for the braino; FWIW, I'd rather add

static inline struct p9_fid *fid_clone(struct p9_fid *fid)
{
	if (IS_ERR(fid))
		return fid;
	return p9_client_walk(fid, 0, NULL, 1);
}

and turn those into fid_clone(v9fs_parent_fid(old_dentry)), etc.  Has an
extra benefit of simplifying several other places.  I'll fix and post
(with credits to you for spotting the bug in question, of course).