[libvirt] [PATCH] qemu: fix return value issue

[ajia at redhat.com]

whether or not previous return value is -1, the following codes will be 
executed for a inactive guest in src/qemu/qemu_driver.c:
ret = virDomainSaveConfig(driver->configDir, persistentDef);
and if everything is okay, 'ret' is assigned to 0, the previous 'ret'
will be overwritten, this patch will fix this issue.  

* src/qemu/qemu_driver.c: avoid return value is overwritten when give a argument
  in out of blkio weight range for a inactive guest.

* how to reproduce?
  % virsh blkiotune ${guestname} --weight 10
  % echo $?

  Note: guest must be inactive, argument 10 in out of blkio weight range, 
  however, virsh hasn't raised any error information, and return value is 0.

  https://bugzilla.redhat.com/show_bug.cgi?id=726304

Signed-off-by: Alex Jia <ajia at redhat.com>
---
 src/qemu/qemu_driver.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index b673fd5..aaccddf 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -5688,7 +5688,9 @@ static int qemuDomainSetBlkioParameters(virDomainPtr dom,
                 ret = -1;
             }
         }
-        ret = virDomainSaveConfig(driver->configDir, persistentDef);
+
+        if(virDomainSaveConfig(driver->configDir, persistentDef) < 0)
+            goto cleanup;
     }
 
 cleanup:
-- 
1.7.1