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

[ajia at 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 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) {
-- 
1.7.1