[Qemu-devel] Re: [PATCH] block: Use error codes from lower levels for error message

[Kevin Wolf <kwolf@redhat.com>]

Am 18.07.2010 21:42, schrieb Stefan Weil:
> "No such file or directory" is a misleading error message
> when a user tries to open a file with wrong permissions.
> 
> Cc: Kevin Wolf <kwolf@redhat.com>
> Signed-off-by: Stefan Weil <weil@mail.berlios.de>
> ---
>  block.c |   12 ++++++++----
>  1 files changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/block.c b/block.c
> index f837876..2f80540 100644
> --- a/block.c
> +++ b/block.c
> @@ -330,16 +330,20 @@ BlockDriver *bdrv_find_protocol(const char *filename)
>      return NULL;
>  }
>  
> -static BlockDriver *find_image_format(const char *filename)
> +static BlockDriver *find_image_format(const char *filename, int *error)

Wouldn't it be a more natural interface to return an 0/-errno int and
pass the BlockDriver* by reference? I think we already have some
function that work this way in the block code, but I can't remember any
that get an int *error.

>  {
>      int ret, score, score_max;
>      BlockDriver *drv1, *drv;
>      uint8_t buf[2048];
>      BlockDriverState *bs;
>  
> +    *error = -ENOENT;

Why -ENOENT is the default would be clearer if you moved it down next to
the drv = NULL before the loop that searches for the driver.

Apart from these minor nitpicks it looks good.

Kevin