Re: [Qemu-devel] [PATCH] qemu-img: Print error if check failed

[Markus Armbruster]

Max Reitz <address@hidden> writes:

> Currently, if bdrv_check() fails either by returning -errno or having
> check_errors set, qemu-img check just exits with 1 after having told the
> user that there were no errors on the image. This is bad.
>
> Instead of printing the check result if there were internal errors which
> were so bad that bdrv_check() could not even complete with 0 as a return
> value, qemu-img check should inform the user about the error.
>
> Signed-off-by: Max Reitz <address@hidden>
> ---
>  qemu-img.c | 21 ++++++++++++++-------
>  1 file changed, 14 insertions(+), 7 deletions(-)
>
> diff --git a/qemu-img.c b/qemu-img.c
> index 09e7e72..731502c 100644
> --- a/qemu-img.c
> +++ b/qemu-img.c
> @@ -687,16 +687,23 @@ static int img_check(int argc, char **argv)
>          check->corruptions_fixed    = corruptions_fixed;
>      }
>  
> -    switch (output_format) {
> -    case OFORMAT_HUMAN:
> -        dump_human_image_check(check, quiet);
> -        break;
> -    case OFORMAT_JSON:
> -        dump_json_image_check(check, quiet);
> -        break;
> +    if (!ret) {
> +        switch (output_format) {
> +        case OFORMAT_HUMAN:
> +            dump_human_image_check(check, quiet);
> +            break;
> +        case OFORMAT_JSON:
> +            dump_json_image_check(check, quiet);
> +            break;
> +        }
>      }
>  
>      if (ret || check->check_errors) {
> +        if (ret) {
> +            error_report("Check failed: %s", strerror(-ret));
> +        } else {
> +            error_report("Check failed");
> +        }
>          ret = 1;
>          goto fail;
>      }

Non-zero ret can only come from bdrv_check() via collect_image_check().
bdrv_check() is specified to return zero or -errno.  Okay.

Aside: ret is used for error codes, 0/-1 and for the return value
0/1/2/3/63.  Unclean, but not this patch's fault.

Reviewed-by: Markus Armbruster <address@hidden>