[libvirt] [PATCH 5/8] UndefineFlags: Implement qemu driver handling

[Osier Yang]

于 2011年07月14日 02:01, Eric Blake 写道:
> On 07/13/2011 04:19 AM, Osier Yang wrote:
>> ---
>>   src/qemu/qemu_driver.c |   31 +++++++++++++++++++++++++++----
>>   1 files changed, 27 insertions(+), 4 deletions(-)
>>
>> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
>> index f962e2c..a9f6986 100644
>> --- a/src/qemu/qemu_driver.c
>> +++ b/src/qemu/qemu_driver.c
>> @@ -2402,10 +2402,8 @@ cleanup:
>>   static char *
>>   qemuDomainManagedSavePath(struct qemud_driver *driver, virDomainObjPtr vm) {
>>       char *ret;
>> -    char uuidstr[VIR_UUID_STRING_BUFLEN];
>> -    virUUIDFormat(vm->def->uuid, uuidstr);
>>
>> -    if (virAsprintf(&ret, "%s/%s.save", driver->saveDir, uuidstr)<  0) {
>> +    if (virAsprintf(&ret, "%s/%s.save", driver->saveDir, vm->def->name)<  0) {
> This hunk won't apply to existing libvirt.git.  Did you forget to rebase
> out your first attempt?
>

Ah, yes.

>> @@ -4312,6 +4315,20 @@ static int qemudDomainUndefine(virDomainPtr dom) {
>>           goto cleanup;
>>       }
>>
>> +    if (flags&  VIR_DOMAIN_UNDEFINE_MANAGED_STATE) {
>> +        name = qemuDomainManagedSavePath(driver, vm);
>> +
>> +        if (name == NULL)
>> +            goto cleanup;
>> +
>> +        if (virFileExists(name)&&  (unlink(name)<  0)) {
>> +            qemuReportError(VIR_ERR_INTERNAL_ERROR,
>> +                            _("failed on removing domain managed state "
>> +                            "file '%s'"), name);
>> +            goto cleanup;
>> +        }
>> +    }
> I think we need to explicitly reject attempts to undefine a domain while
> a state file exists.  That is, I think this logic needs to be:
>
> name = qemuDomainManagedSavePath(driver, vm);
> if (name == NULL)
>      goto cleanup;
> if (virFileExists(name)) {
>      if (flags&  VIR_DOMAIN_UNDEFINE_MANAGED_STATE) {
>          if (unlink(name)<  0) {
>              error - failed to remove
>          }
>      } else {
>          error - refusing to undefine with managed state file present
>     }
> }
>
> Yes, it will change existing behavior (previously, you could undefine a
> domain and leave the state file behind), but that was unsafe, and this
> is arguably a bug fix.  The default should be as safe as possible, with
> the flags (VIR_DOMAIN_UNDEFINE_MANAGED_STATE) in place to make things
> faster.
>

This answer my question in 3/8
>> @@ -8487,6 +8509,7 @@ static virDriver qemuDriver = {
>>       .domainCreateWithFlags = qemudDomainStartWithFlags, /* 0.8.2 */
>>       .domainDefineXML = qemudDomainDefine, /* 0.2.0 */
>>       .domainUndefine = qemudDomainUndefine, /* 0.2.0 */
>> +    .domainUndefineWithFlags = qemudDomainUndefineWithFlags, /* 0.9.4 */
> Also, I think that for every hypervisor that supports domainUndefine, we
> should add a (trivial) domainUndefine[With]Flags wrapper, so that the
> new API is available everywhere in 0.9.4, but do that as a separate patch.

Agree, even if other hypervisors except libxl and qemu don't support
managed saving.

> I'm about to post a series to add virDomainSaveFlags, which might serve
> as an example for what I'm thinking about.  That series will add a
> no-semantic-change wrapper in the first commit, and only later changes
> the qemu wrapper to learn to honor a new flag value.
>