[libvirt] [PATCH] qemu: add return value check

[Alex Jia]

On 09/27/2011 06:55 AM, Eric Blake wrote:
> On 09/26/2011 01:52 AM, ajia at redhat.com wrote:
>> From: Alex Jia<ajia at redhat.com>
>>
>> * src/qemu/qemu_migration.c: if 'vmdef' is NULL, the function
>>    virDomainSaveConfig still dereferences it, it doesn't make
>>    sense, so should add return value check to make sure 'vmdef'
>>    is non-NULL before calling virDomainSaveConfig.
>>
>> Signed-off-by: Alex Jia<ajia at redhat.com>
>> ---
>>   src/qemu/qemu_migration.c |    8 +++++++-
>>   1 files changed, 7 insertions(+), 1 deletions(-)
>
> Good catch, but not quite the right fix.
>
>> +++ b/src/qemu/qemu_migration.c
>> @@ -2580,8 +2580,14 @@ qemuMigrationFinish(struct qemud_driver *driver,
>>               vm->persistent = 1;
>>               if (mig->persistent)
>>                   vm->newDef = vmdef = mig->persistent;
>> -            else
>> +            else {
>
> This violates formatting conventions (if one side of if-else uses {}, 
> then both must use it).
Because 'if' only includes one statement, I haven't use {} surround with 
this statement,
however, the following usage is better:

if {
...
} else {
...
}
>
>>                   vmdef = virDomainObjGetPersistentDef(driver->caps, 
>> vm);
>> +                if (!vmdef) {
>> +                    qemuReportError(VIR_ERR_INTERNAL_ERROR, "%s",
>> +                                    _("can't get vmdef"));
>> +                    goto endjob;
>
> This is wrong for v3proto.  A better fix is probably this one, 
> although I'd feel more comfortable with Dan reviewing it and/or 
> running the TCK migration stress test on it:
>
> diff --git i/src/qemu/qemu_migration.c w/src/qemu/qemu_migration.c
> index 0a5a13d..1bef50a 100644
> --- i/src/qemu/qemu_migration.c
> +++ w/src/qemu/qemu_migration.c
> @@ -2582,7 +2582,8 @@ qemuMigrationFinish(struct qemud_driver *driver,
>                  vm->newDef = vmdef = mig->persistent;
>              else
>                  vmdef = virDomainObjGetPersistentDef(driver->caps, vm);
> -            if (virDomainSaveConfig(driver->configDir, vmdef) < 0) {
> +            if (!vmdef ||
> +                virDomainSaveConfig(driver->configDir, vmdef) < 0) {
>                  /* Hmpf.  Migration was successful, but making it 
> persistent
>                   * was not.  If we report successful, then when this 
> domain
>                   * shuts down, management tools are in for a 
> surprise.  On the
>
>
Yeah, but in order to debug,  whether we still need to write error/debug 
log to record
which condition is failed.


Thanks,
Alex