[libvirt] [PATCH v2] virsh: avoid missing zero value judgement in cmdBlkiotune

[Alex Jia]

On 07/28/2011 05:04 PM, Alex Jia wrote:
> * tools/virsh.c: avoid missing zero value judgement in cmdBlkiotune, when
>    weight is equal to 0, the cmdBlkiotune will not raise any error information
>    when judge weight value first time, and execute else branch to judge weight
>    value again, strncpy(temp->field, VIR_DOMAIN_BLKIO_WEIGHT, sizeof(temp->field))
>    will be not executed for ever. However, if and only if param->field is equal
>    to VIR_DOMAIN_BLKIO_WEIGHT, underlying qemuDomainSetBlkioParameters function
>    will check whether weight value is in range [100, 1000].
>
> * how to reproduce?
>
>    % virsh blkiotune ${guestname} --weight 0
>
> Signed-off-by: Alex Jia<ajia at redhat.com>
> ---
>   tools/virsh.c |   11 +++++------
>   1 files changed, 5 insertions(+), 6 deletions(-)
>
> diff --git a/tools/virsh.c b/tools/virsh.c
> index 8bd22dc..512f2c6 100644
> --- a/tools/virsh.c
> +++ b/tools/virsh.c
> @@ -4037,14 +4037,13 @@ cmdBlkiotune(vshControl * ctl, const vshCmd * cmd)
>           goto cleanup;
>       }
>
> -    if (weight) {
> -        nparams++;
> -        if (weight<  0) {
> -            vshError(ctl, _("Invalid value of %d for I/O weight"), weight);
> -            goto cleanup;
> -        }
> +    if (weight<= 0) {
> +        vshError(ctl, _("Invalid value of %d for I/O weight"), weight);
> +        goto cleanup;
>       }
>
> +    nparams++;
> +
>       if (nparams == 0) {
>           /* get the number of blkio parameters */
>           if (virDomainGetBlkioParameters(dom, NULL,&nparams, flags) != 0) {
Hmm, the above patch will introduce new issue, if blkiotune without any 
weight option,
vshError will also be hit, that is not we expected.

The reason of root is vshCommandOptInt will assign 0 to weight if option 
not found
and not required, so we need to specifically deal with 0 value, I will 
renew consider this
issue, so cancel this patch.

Thanks,
Alex