Re: [PATCH 03/41] VFS: Make lookup_hash() return a struct path

[Erez Zadok]

In message <1256152779-10054-4-git-send-email-vaurora@xxxxxxxxxx>, Valerie Aurora writes:
> From: Jan Blunck <jblunck@xxxxxxx>
> 
> This patch changes lookup_hash() into returning a struct path.

Actually, lookup_hash now also takes a qstr.

This is a somewhat involved patch.  I think more documentation is needed to
list all the places it touches and changes, b/c now struct path has to
propagate in various other places.  (In general, passing struct path instead
of struct dentry is going in the right direction: eventually we could get rid
of lookup_one_len.)

> @@ -1219,14 +1219,22 @@ out:
>   * needs parent already locked. Doesn't follow mounts.
>   * SMP-safe.
>   */
> -static struct dentry *lookup_hash(struct nameidata *nd)
> +static int lookup_hash(struct nameidata *nd, struct qstr *name,
> +		       struct path *path)
>  {

I suggest you document above this function what the @name and @path are for,
who is supposed to allocate and free them, caller/callee's responsibilities,
side effects (if any), new return status upon success/failure, etc.

>  
>  	err = inode_permission(nd->path.dentry->d_inode, MAY_EXEC);
>  	if (err)
> -		return ERR_PTR(err);
> -	return __lookup_hash(&nd->last, nd->path.dentry, nd);
> +		return err;

At least initially, while all this code is being developed, it might also be
a good idea to add

   BUG_ON(!name);
   BUG_ON(!path);

here and possibly in other places which are now taking new pointers.

Erez.
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