Re: [libvirt] [PATCH 1/2] libvirt/qemu - support updating inactive domains (take 2)
On Thu, 24 Feb 2011 15:29:46 +0800
Hu Tao <hutao(a)cn.fujitsu.com> wrote:
> > > +
> > > + driver = dom->conn->privateData;
> > > + qemuDriverLock(driver);
> > > + vm = virDomainFindByUUID(&driver->domains, dom->uuid);
> > > + if (!vm) {
> > > + qemuReportError(VIR_ERR_NO_DOMAIN, _("cannot find domain
'%s'"),
> > > + dom->name);
> > > + goto unlock_out;
> > > + }
> > > +
> > > + if (qemuDomainObjBeginJobWithDriver(driver, vm) < 0) {
> > > + /*
> > > + * For now, just allow updating inactive domains. Further
development
> > > + * will allow updating both active domain and its config file at
> > > + * the same time.
> > > + */
> > > + qemuReportError(VIR_ERR_INVALID_ARG,
> > > + _("cannot update alive domain : %s"),
__FUNCTION__);
> >
> > I think we can silently fail here. Currently this function
(qemuDomainModifyDevicePersistent)
> > is called only for modifying inactive domains.
> >
> It seems...."virDomainObjIsActive(vm) check" is lacked..
Yes. What about checking for flag VIR_DOMAIN_DEVICE_MODIFY_LIVE? This
flag is set if domain is active, for example, see cmdAttachDisk().
checking virDomainObjIsActive(vm) under lock is required.
As you pointed out, if --persistent is specified in virsh attach-disk,
==
if (vshCommandOptBool(cmd, "persistent")) {
flags = VIR_DOMAIN_DEVICE_MODIFY_CONFIG;
if (virDomainIsActive(dom) == 1)
flags |= VIR_DOMAIN_DEVICE_MODIFY_LIVE;
ret = virDomainAttachDeviceFlags(dom, buffer, flags);
} else {
ret = virDomainAttachDevice(dom, buffer);
}
==
Both of MODIFY_CONFIG, MODIFY_LIVE flags are always set if domain is alive.
* Attach a virtual device to a domain, using the flags parameter
* to control how the device is attached. VIR_DOMAIN_DEVICE_MODIFY_CURRENT
* specifies that the device allocation is made based on current domain
* state. VIR_DOMAIN_DEVICE_MODIFY_LIVE specifies that the device shall be
* allocated to the active domain instance only and is not added to the
* persisted domain configuration. VIR_DOMAIN_DEVICE_MODIFY_CONFIG
* specifies that the device shall be allocated to the persisted domain
* configuration only. Note that the target hypervisor must return an
* error if unable to satisfy flags. E.g. the hypervisor driver will
* return failure if LIVE is specified but it only supports modifying the
* persisted device allocation.
From above, if VIR_DOMAIN_DEVICE_MODIFY_LIVE is set....this function
should fail?
Ok. But no explanation of API when both of MODIFY_LIVE and
MODIFY_CONFIG
are set at the same time.
I'll add a test of VIR_DOMAIN_DEVICE_MODIFY_LIVE for now. But I'll remove it
later.
What we want to know here is the caller wants persistent change or not.
I think I'll update this function to allow modification of active domain
in future.
Thanks,
-Kame