Re: [Qemu-devel] [PATCH 2/3] qemu-io: Respect early image end for map

[Benoît Canet]

The Saturday 11 Oct 2014 à 11:53:40 (+0200), Max Reitz wrote :
> Am 10.10.2014 um 14:03 schrieb Benoît Canet:
> >>+        } else if (!num) {
> >>+            error_report("Unexpected end of image");
> >>+            return 0;
> >I think this test can miss some case of Unexpected end of image.
> >
> >For example supose that in map_is_allocated the first bdrv_is_allocated
> >actually succeed then *pnum = num. Then the bottom loop has exit on failure
> >and the function return.
> >
> >in map_f &num is map_is_allocated *pnum so map_f's num != 0 and this very 
> >test
> >fails to see the unexpected end of image error.
> 
> num != 0 because some sectors where successfully queried. In my opinion, we
> should print the information about them we have. Then, the do-while loop is
> repeated; and this time, map_is_allocated() either again returns num > 0
> (for whatever reason, but I'd be fine with it) or, more probably, it'll be
> num == 0 this time. So the error is not missed, it's just printed one
> iteration later.

Ok that make sense.

Best regards

Benoît

> 
> Max
> 
> >Best regards
> >
> >Benoît
> >
> >>          }
> >>          retstr = ret ? "    allocated" : "not allocated";
> >>-- 
> >>2.0.4
> >>
> >>
> 
>