[libvirt] [PATCH v3] virsh: avoid missing zero value judgement in cmdBlkiotune

[ajia redhat com]

* 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 redhat com>
---
 tools/virsh.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/tools/virsh.c b/tools/virsh.c
index 8bd22dc..f24050d 100644
--- a/tools/virsh.c
+++ b/tools/virsh.c
@@ -4037,12 +4037,12 @@ cmdBlkiotune(vshControl * ctl, const vshCmd * cmd)
         goto cleanup;
     }
 
-    if (weight) {
-        nparams++;
-        if (weight < 0) {
+    if (vshCommandOptInt(cmd, "weight", &weight) > 0) {
+        if (weight <= 0) {
             vshError(ctl, _("Invalid value of %d for I/O weight"), weight);
             goto cleanup;
         }
+        nparams++;
     }
 
     if (nparams == 0) {
-- 
1.7.1