Re: [PATCH 1/1] cr: fix ckpt_obj_fetch return values (v2)

["Serge E. Hallyn" <serue-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>]

Quoting Oren Laadan (orenl-eQaUEPhvms7ENvBUuze7eA@public.gmane.org):
> > @@ -1246,9 +1244,7 @@ int restore_mm_obj(struct ckpt_ctx *ctx, int mm_objref)
> >  	int ret;
> >  
> >  	mm = ckpt_obj_fetch(ctx, mm_objref, CKPT_OBJ_MM);
> > -	if (!mm)
> > -		return -EINVAL;
> > -	else if (IS_ERR(mm))
> > +	if (IS_ERR(mm))
> >  		return -EINVAL;
> 			^^^^^^
> should be:		PTR_ERR(mm);

Oops, right.

> > diff --git a/fs/pipe.c b/fs/pipe.c
> > index ab2de3c..b284dcb 100644
> > --- a/fs/pipe.c
> > +++ b/fs/pipe.c
> > @@ -982,14 +982,12 @@ struct file *pipe_file_restore(struct ckpt_ctx *ctx, struct ckpt_hdr_file *ptr)
> >  		return ERR_PTR(-EINVAL);
> >  
> >  	file = ckpt_obj_fetch(ctx, h->pipe_objref, CKPT_OBJ_FILE);
> > -	if (IS_ERR(file))
> > -		return file;
> >  	/*
> > -	 * If ckpt_obj_fetch() returned NULL, then this is the first
> > +	 * If ckpt_obj_fetch() returned -EINVAL, then this is the first
> >  	 * time we see this pipe so need to restore the contents.
> >  	 * Otherwise, use the file pointer skip forward.
> >  	 */
> > -	if (!file) {
> > +	if (PTR_ERR(file) == -EINVAL) {
> 
> ckpt_obj_fetch() will also fail with -EINVAL if the type of the object
> found doesn't match the type that was requested. Hence why originally
> the two return values. So I changed that latter to report -ENOMSG (that
> is:  /* No message of desired type */)

Hmm, yes I was thinking of the checkpoint case where mismatched types
would be strictly an objhash bug.  You're right, this case can just
be a bad checkpoint image!

thanks,
-serge