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Re: [libvirt] [PATCH 3/5] libvirt/qemu - support persistent modification of devices.



On Mon, 14 Mar 2011 13:29:13 +0800
Wen Congyang <wency cn fujitsu com> wrote:

> At 03/03/2011 09:11 AM, KAMEZAWA Hiroyuki Write:
> >>From f7a997e3cd58cfac81e131afdd20c3691267831d Mon Sep 17 00:00:00 2001
> > From: KAMEZAWA Hiroyuki <kamezawa hiroyu jp fujitsu com>
> > Date: Thu, 3 Mar 2011 09:43:07 +0900
> > Subject: [PATCH 3/5] libivrt/qemu - support persistent modification of devices.
> > 
> > Now, virsh attach-***/detach-*** has --persistent option and
> > it can update XML definition of inactive domains.
> > Now, disk and nic are supported in Xen, but none in qemu.
> > 
> > This patch adds a function for permanent modification for qemu.
> > Following patches will add disk/network suport.
> > 
> > TODO:
> >   - finally, need to do hotplug + XML modification for active domain.
> > 
> > Changelog v3->v4
> >   - fixed trailing white spaces.
> >   - splitted into 2 part and this patch only contains wrappers.
> > Changelog v2->v3:
> >   - clean ups.
> >   - handle all VIR_DOMAIN_DEVICE_MODIFY_XXX flags.
> > ---
> >  src/qemu/qemu_driver.c |  143 ++++++++++++++++++++++++++++++++++++++++++++----
> >  1 files changed, 131 insertions(+), 12 deletions(-)
> > 
> > diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
> > index c9095bb..3248cdc 100644
> > --- a/src/qemu/qemu_driver.c
> > +++ b/src/qemu/qemu_driver.c
> > @@ -4099,16 +4099,131 @@ cleanup:
> >      return ret;
> >  }
> >  
> > -static int qemudDomainAttachDeviceFlags(virDomainPtr dom,
> > +/*
> > + * Attach a device given by XML, the change will be persistent
> > + * and domain XML definition file is updated.
> > + */
> > +static int qemuDomainAttachDevicePersistent(virDomainDefPtr vmdef,
> > +                                            virDomainDeviceDefPtr newdev)
> > +{
> > +
> > +    /* At first, check device confliction */
> > +    switch(newdev->type) {
> > +    default:
> > +        qemuReportError(VIR_ERR_INVALID_ARG, "%s",
> 
> When the device is not supported, we should use VIR_ERR_CONFIG_UNSUPPORTED
> instead of VIR_ERR_INVALID_ARG.
> 

will change.

> > +                        _("Sorry, the device is not suppored for now"));
> > +        return -1;
> > +    }
> > +
> > +    return 0;
> > +}
> > +
> > +static int qemuDomainDetachDevicePersistent(virDomainDefPtr vmdef,
> > +                                       virDomainDeviceDefPtr device)
> 
> The coding style is wrong: virDomainDeviceDefPtr shoulde be left justified
> with virDomainDefPtr.
> 

Hmm, okay.


> > +{
> > +    switch(device->type) {
> > +    default:
> > +        qemuReportError(VIR_ERR_INVALID_ARG, "%s",
> > +                        _("Sorry, the device is not suppored for now"));
> > +        return -1;
> > +    }
> > +    return 0;
> > +}
> > +
> > +static int qemuDomainModifyDevicePersistent(virDomainPtr dom,
> >                                          const char *xml,
> > -                                        unsigned int flags) {
> > -    if (flags & VIR_DOMAIN_DEVICE_MODIFY_CONFIG) {
> > -        qemuReportError(VIR_ERR_OPERATION_INVALID,
> > -                        "%s", _("cannot modify the persistent configuration of a domain"));
> > +                                        unsigned int attach, int flags)
> 
> Why do you modify the type of flag?
> 

my bug.


> > +{
> > +    struct qemud_driver *driver;
> > +    virDomainDeviceDefPtr device;
> > +    virDomainDefPtr vmdef;
> > +    virDomainObjPtr vm;
> > +    int ret = -1;
> > +
> > +    if (!dom || !dom->conn || !dom->name || !xml) {
> 
> dom and dom->conn does not need check, they are always not null.
> 

Ok, so, Xen code should be fixed. (This is just a copy-n-paste.)


> > +        qemuReportError(VIR_ERR_INTERNAL_ERROR,
> > +                        _("internal error : %s"),  __FUNCTION__);
> 
> Do not use __FUNCTION__ here, the macro qemuReportError will do it.
> > +        return -1;
> > +    }
> > +    /*
> > +     * When both of MODIFY_CONFIG and MODIFY_LIVE is specified at the same time,
> > +     * return error for now. We should support this later.
> > +     */
> > +    if (flags & VIR_DOMAIN_DEVICE_MODIFY_LIVE) {
> > +        qemuReportError(VIR_ERR_INVALID_ARG, "%s",
> 
> Please use VIR_ERR_OPERATION_INVALID instead of VIR_ERR_INVALID_ARG.
> 
ok.

> > +                        _("Now, cannot modify alive domain and its definition "
> > +                          "at the same time."));
> >          return -1;
> >      }
> >  
> > -    return qemudDomainAttachDevice(dom, xml);
> > +    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);
> 
> You use UUID to search the domain, so the error message should be:
> no domain with matching uuid '%s'
> 
ok.


> > +        goto unlock_out;
> > +    }
> > +
> > +    if (qemuDomainObjBeginJobWithDriver(driver, vm) < 0)
> > +        goto unlock_out;
> > +
> > +    if (virDomainObjIsActive(vm)) {
> > +        /*
> > +         * 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_OPERATION_INVALID, "%s",
> > +              _("Now, it's unsupported to update active domain's definition."));
> > +        goto endjob;
> > +    }
> > +
> > +    vmdef = virDomainObjGetPersistentDef(driver->caps, vm);
> > +
> > +    if (!vmdef)
> > +        goto endjob;
> > +
> > +    device = virDomainDeviceDefParse(driver->caps,
> > +                 vmdef, xml, VIR_DOMAIN_XML_INACTIVE);
> > +    if (!device)
> > +        goto endjob;
> > +
> > +    if (attach)
> > +        ret = qemuDomainAttachDevicePersistent(vmdef, device);
> > +    else
> > +        ret = qemuDomainDetachDevicePersistent(vmdef, device);
> > +
> > +    if (!ret) /* save the result */
> > +        ret = virDomainSaveConfig(driver->configDir, vmdef);
> > +
> > +    virDomainDeviceDefFree(device);
> > +
> > +endjob:
> > +    if (qemuDomainObjEndJob(vm) == 0)
> > +        vm = NULL;
> > +    if (vm)
> > +        virDomainObjUnlock(vm);
> 
> When qemuDomainObjBeginJobWithDriver() failed, we should unlock the domain.
> So we should do it when we goto unlock_out.
> 

ok.


> > +unlock_out:
> > +    qemuDriverUnlock(driver);
> > +    return ret;
> > +}
> > +
> > +static int qemudDomainAttachDeviceFlags(virDomainPtr dom,
> > +                                        const char *xml,
> > +                                        unsigned int flags)
> > +{
> > +    if (flags & VIR_DOMAIN_DEVICE_MODIFY_CONFIG)
> > +        return qemuDomainModifyDevicePersistent(dom, xml, 1, flags);
> > +
> > +    if (flags & VIR_DOMAIN_DEVICE_MODIFY_LIVE)
> > +        return qemudDomainAttachDevice(dom, xml);
> > +
> > +    qemuReportError(VIR_ERR_INVALID_ARG,
> > +        _("bad flag: %x only MODIFY_LIVE, MODIFY_CONFIG are supported now"),
> > +       flags);
> > +
> > +    return -1;
> >  }
> >  
> >  
> > @@ -4322,13 +4437,17 @@ cleanup:
> >  static int qemudDomainDetachDeviceFlags(virDomainPtr dom,
> >                                          const char *xml,
> >                                          unsigned int flags) {
> > -    if (flags & VIR_DOMAIN_DEVICE_MODIFY_CONFIG) {
> > -        qemuReportError(VIR_ERR_OPERATION_INVALID,
> > -                        "%s", _("cannot modify the persistent configuration of a domain"));
> > -        return -1;
> > -    }
> >  
> > -    return qemudDomainDetachDevice(dom, xml);
> > +    if (flags & VIR_DOMAIN_DEVICE_MODIFY_CONFIG)
> > +        return qemuDomainModifyDevicePersistent(dom, xml, 0, flags);
> > +
> > +    if (flags & VIR_DOMAIN_DEVICE_MODIFY_LIVE)
> > +        return qemudDomainDetachDevice(dom, xml);
> > +
> > +    qemuReportError(VIR_ERR_INVALID_ARG,
> > +        _("bad flag: %x only MODIFY_LIVE, MODIFY_CONFIG are supported now"),
> > +        flags);
> > +    return -1;
> >  }
> >  
> >  static int qemudDomainGetAutostart(virDomainPtr dom,
> 
> 

Thank you.
-Kame


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