[libvirt] [PATCH 3/5] vz: implement managed migration

[Nikolay Shirokovskiy]

On 19.05.2016 13:38, Maxim Nestratov wrote:
> 18.05.2016 11:11, Nikolay Shirokovskiy пишет:
> 
>> The newest version of migration protocol - version 3 with parameters is implemented.
>> Supported flags is VIR_MIGRATE_PAUSED only. Supported parameters are
>> VIR_MIGRATE_PARAM_URI and VIR_MIGRATE_PARAM_DEST_NAME. VIR_MIGRATE_PARAM_DEST_XML
>> is in VZ_MIGRATION_PARAMETERS for technical onyl reasons.
>>
>> Signed-off-by: Nikolay Shirokovskiy <nshirokovskiy at virtuozzo.com>
>> ---
>>   src/vz/vz_driver.c | 443 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>>   src/vz/vz_sdk.c    |  42 +++++
>>   src/vz/vz_sdk.h    |   6 +
>>   3 files changed, 491 insertions(+)
>>

...

>> +static int
>> +vzDomainMigratePrepare3Params(virConnectPtr conn,
>> +                              virTypedParameterPtr params,
>> +                              int nparams,
>> +                              const char *cookiein,
>> +                              int cookieinlen,
>> +                              char **cookieout,
>> +                              int *cookieoutlen,
>> +                              char **uri_out,
>> +                              unsigned int flags)
>> +{
>> +    vzConnPtr privconn = conn->privateData;
>> +    const char *miguri = NULL;
>> +    const char *dname = NULL;
>> +    virDomainObjPtr dom = NULL;
>> +    vzMigrationCookiePtr mig = NULL;
>> +    int ret = -1;
>> +
>> +    virCheckFlags(VZ_MIGRATION_FLAGS, -1);
>> +
>> +    if (virTypedParamsValidate(params, nparams, VZ_MIGRATION_PARAMETERS) < 0)
>> +        goto cleanup;
>> +
>> +    if (virTypedParamsGetString(params, nparams,
>> +                                VIR_MIGRATE_PARAM_URI, &miguri) < 0 ||
>> +        virTypedParamsGetString(params, nparams,
>> +                                VIR_MIGRATE_PARAM_DEST_NAME, &dname) < 0)
>> +        goto cleanup;
>> +
>> +    /* We must set uri_out if miguri is not set. This is direct
>> +     * managed migration requirement */
>> +    if (!miguri && !(*uri_out = vzMigrationCreateURI()))
>> +        goto cleanup;
>> +
>> +    if (!(mig = vzEatCookie(cookiein, cookieinlen)))
>> +        goto cleanup;
>> +
>> +    memcpy(mig->session_uuid, privconn->driver->session_uuid, VIR_UUID_BUFLEN);
>> +
>> +    if (vzBakeCookie(mig, cookieout, cookieoutlen) < 0)
>> +        goto cleanup;
>> +
>> +    if (!(dom = vzNewDomain(privconn->driver,
>> +                            dname ? dname : mig->name, mig->uuid)))
>> +        goto cleanup;
> 
> Just realized that since virDomainObjListAdd returns a valid and existing domain if its name and uuid is the same this call can cause some problems.
> For instance, if a user specified the same source and destination uri, the migration will fail and Finish code will remove the domain from list.
> Thus what about the following chunk instead existing?:
> 
>     virObjectLock(privconn->driver);
>     dom = virDomainObjListFindByUUID(privconn->driver->domains, mig->uuid);
>     if (dom) {
>         char uuidstr[VIR_UUID_STRING_BUFLEN];
>         virUUIDFormat(mig->uuid, uuidstr);
>         virReportError(VIR_ERR_INTERNAL_ERROR,
>                        _("A domain with uuid '%s' already exists"),
>                        uuidstr);
>         goto unlock;
>     }
> 
>     if (!(dom = vzNewDomain(privconn->driver,
>                             dname ? dname : mig->name, mig->uuid)))
>         goto unlock;
> 
>     ret = 0;
> 
>  unlock:
>     virObjectUnlock(privconn->driver);
> 

Looks reasonable.

>> +
>> +    ret = 0;
>> +
>> + cleanup:
>> +    vzMigrationCookieFree(mig);
>> +    if (dom)
>> +        virObjectUnlock(dom);
>> +    return ret;
>> +}
>> +