On 31.08.2015 10:42, Nikolay Shirokovskiy wrote:
>
>
> On 28.08.2015 19:04, Michal Privoznik wrote:
>> On 28.08.2015 11:29, Nikolay Shirokovskiy wrote:
>>>
>>>
>>> On 28.08.2015 08:54, Michal Privoznik wrote:
>>>> On 27.08.2015 12:23, Nikolay Shirokovskiy wrote:
>>>>> From: Nikolay Shirokovskiy <Nikolay Shirokovskiy nshirokovskiy@xxxxxxxxxxxxx>
>>>>>
>>>>> Direct migration should work if *perform3 is present but *perform
>>>>> is not. This is situation when driver migration is implemented
>>>>> after new version of driver function is introduced. We should not
>>>>> be forced to support old version too as its parameter space is
>>>>> subspace of newer one.
>>>>>
>>>>> Signed-off-by: Nikolay Shirokovskiy <nshirokovskiy@xxxxxxxxxxxxx>
>>>>> ---
>>>>> src/libvirt-domain.c | 3 ++-
>>>>> 1 files changed, 2 insertions(+), 1 deletions(-)
>>>>>
>>>>> diff --git a/src/libvirt-domain.c b/src/libvirt-domain.c
>>>>> index 6ab50ba..c89775b 100644
>>>>> --- a/src/libvirt-domain.c
>>>>> +++ b/src/libvirt-domain.c
>>>>> @@ -3427,7 +3427,8 @@ virDomainMigrateDirect(virDomainPtr domain,
>>>>> NULLSTR(xmlin), flags, NULLSTR(dname), NULLSTR(dconnuri),
>>>>> NULLSTR(miguri), bandwidth);
>>>>>
>>>>> - if (!domain->conn->driver->domainMigratePerform) {
>>>>> + if (!domain->conn->driver->domainMigratePerform &&
>>>>> + !domain->conn->driver->domainMigratePerform3) {
>>>>> virReportUnsupportedError();
>>>>> return -1;
>>>>> }
>>>>>
>>>>
>>>>
>>>> Hm.. domainMigratePerform3 will be used iff connection driver has
>>>> VIR_DRV_FEATURE_MIGRATION_V3 feature. But this check will require that
>>>> regardless. What if we check the presence of implementation with respect
>>>> to that?
>>> I see you mean actual driver could be behind remote one and checking
>>> for perform3 always gives true so we need to check for feature instead?
>>
>> Sort of. domainMigratePerform3 is used only if the feature is present.
>> But after your patch, the function implementation would be needed
>> always, even if the feature is not present.
> Why? You can implement version1 or version3 or both for this check to pass.
Unfortunately no. I mean, the current code does not have any fallback. Whenever the feature is detected, domainMigratePerform3 is used and that's it. Therefore I think we are aiming on something among the following lines:
diff --git a/src/libvirt-domain.c b/src/libvirt-domain.c
index cbf08fc..218efe8 100644
--- a/src/libvirt-domain.c
+++ b/src/libvirt-domain.c
@@ -3425,16 +3425,16 @@ virDomainMigrateDirect(virDomainPtr domain,
NULLSTR(xmlin), flags, NULLSTR(dname), NULLSTR(uri),
bandwidth);
- if (!domain->conn->driver->domainMigratePerform) {
- virReportUnsupportedError();
- return -1;
- }
-
/* Perform the migration. The driver isn't supposed to return
* until the migration is complete.
*/
if (VIR_DRV_SUPPORTS_FEATURE(domain->conn->driver, domain->conn,
VIR_DRV_FEATURE_MIGRATION_V3)) {
+ if (!domain->conn->driver->domainMigratePerform3) {
+ virReportUnsupportedError();
+ return -1;
+ }
+
VIR_DEBUG("Using migration protocol 3");
/* dconn URI not relevant in direct migration, since no
* target libvirtd is involved */
@@ -3450,6 +3450,11 @@ virDomainMigrateDirect(virDomainPtr domain,
dname,
bandwidth);
} else {
+ if (!domain->conn->driver->domainMigratePerform) {
+ virReportUnsupportedError();
+ return -1;
+ }
+
VIR_DEBUG("Using migration protocol 2");
if (xmlin) {
virReportError(VIR_ERR_ARGUMENT_UNSUPPORTED, "%s",
The other approach could be:
diff --git a/src/libvirt-domain.c b/src/libvirt-domain.c
index cbf08fc..9d4827a 100644
--- a/src/libvirt-domain.c
+++ b/src/libvirt-domain.c
@@ -3420,12 +3420,18 @@ virDomainMigrateDirect(virDomainPtr domain,
const char *uri,
unsigned long bandwidth)
{
+ bool v3migration;
+
VIR_DOMAIN_DEBUG(domain,
"xmlin=%s, flags=%lx, dname=%s, uri=%s, bandwidth=%lu",
NULLSTR(xmlin), flags, NULLSTR(dname), NULLSTR(uri),
bandwidth);
- if (!domain->conn->driver->domainMigratePerform) {
+ v3migration = VIR_DRV_SUPPORTS_FEATURE(domain->conn->driver, domain->conn,
+ VIR_DRV_FEATURE_MIGRATION_V3);
+
+ if ((!v3migration && !domain->conn->driver->domainMigratePerform) ||
+ (v3migration && !domain->conn->driver->domainMigratePerform3)) {
virReportUnsupportedError();
return -1;
}
@@ -3433,8 +3439,7 @@ virDomainMigrateDirect(virDomainPtr domain,
/* Perform the migration. The driver isn't supposed to return
* until the migration is complete.
*/
- if (VIR_DRV_SUPPORTS_FEATURE(domain->conn->driver, domain->conn,
- VIR_DRV_FEATURE_MIGRATION_V3)) {
+ if (v3migration) {
VIR_DEBUG("Using migration protocol 3");
/* dconn URI not relevant in direct migration, since no
* target libvirtd is involved */
Michal
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