Re: [PATCH 1/3] enhanced ESTALE error handling

[Peter Staubach]

Matthew Wilcox wrote:
> On Fri, Jan 18, 2008 at 10:36:01AM -0500, Peter Staubach wrote:
>   
> > @@ -1025,12 +1027,27 @@ static int fastcall link_path_walk(const
> >  	mntget(save.mnt);
> >  
> >  	result = __link_path_walk(name, nd);
> > -	if (result == -ESTALE) {
> > +	while (result == -ESTALE) {
> > +		/*
> > +		 * If no progress was made looking up the pathname,
> > +		 * then stop and return ENOENT instead of ESTALE.
> > +		 */
> > +		if (nd->dentry == save.dentry) {
> > +			result = -ENOENT;
> > +			break;
> > +		}
> >  		*nd = save;
> >  		dget(nd->dentry);
> >  		mntget(nd->mnt);
> >  		nd->flags |= LOOKUP_REVAL;
> >  		result = __link_path_walk(name, nd);
> > +		/*
> > +		 * If no progress was made this time, then return
> > +		 * ENOENT instead of ESTALE because no recovery
> > +		 * is possible to recover the stale file handle.
> > +		 */
> > +		if (result == -ESTALE && nd->dentry == save.dentry)
> > +			result = -ENOENT;
> >  	}
> >  
> >  	dput(save.dentry);
> >     
>
> Why do you need both of these tests?  The first one should be enough,
> surely?
>
>   

Yes, good point.

> > @@ -1268,8 +1285,8 @@ int path_lookup_open(int dfd, const char
> >   * @create_mode: create intent flags
> >   */
> >  static int path_lookup_create(int dfd, const char *name,
> > -			      unsigned int lookup_flags, struct nameidata *nd,
> > -			      int open_flags, int create_mode)
> > +		unsigned int lookup_flags, struct nameidata *nd,
> > +		int open_flags, int create_mode)
> >     
>
> Gratuitous reformatting?
>
>   

Elimination of an overly long line?

> > @@ -1712,7 +1729,10 @@ int open_namei(int dfd, const char *path
> >  	int acc_mode, error;
> >  	struct path path;
> >  	struct dentry *dir;
> > -	int count = 0;
> > +	int count;
> > +
> > +top:
> > +	count = 0;
> >  
> >  	acc_mode = ACC_MODE(flag);
> >  
> > @@ -1739,7 +1759,8 @@ int open_namei(int dfd, const char *path
> >  	/*
> >  	 * Create - we need to know the parent.
> >  	 */
> > -	error = path_lookup_create(dfd,pathname,LOOKUP_PARENT,nd,flag,mode);
> > +	error = path_lookup_create(dfd, pathname, LOOKUP_PARENT, nd,
> > +				flag, mode);
> >  	if (error)
> >  		return error;
> >  
> > @@ -1812,10 +1833,17 @@ ok:
> >  	return 0;
> >  
> >  exit_dput:
> > +	if (error == -ESTALE)
> > +		d_drop(path.dentry);
> >  	dput_path(&path, nd);
> >  exit:
> >  	if (!IS_ERR(nd->intent.open.file))
> >  		release_open_intent(nd);
> > +	if (error == -ESTALE) {
> > +		d_drop(nd->dentry);
> > +		path_release(nd);
> > +		goto top;
> > +	}
> >     
>
> I wonder if a tail-call might not work better here.

"Tail-call"?

   Thanx...

      ps
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