[libvirt] [Patch v7 1/4] libvirt/qemu - persistent modification of domain.

[Wen Congyang]

At 03/25/2011 04:10 PM, KAMEZAWA Hiroyuki Write:
> This is v7. Dropped patches for Nics and added 2 sanity checks and
> show correct error messages.
> 
> =
>>From 948597237bd9ecfc5c7343fd30efdca37733274e Mon Sep 17 00:00:00 2001
> From: KAMEZAWA Hiroyuki <kamezawa.hiroyu at jp.fujitsu.com>
> Date: Fri, 25 Mar 2011 16:59:55 +0900
> Subject: [PATCHv7 1/4] libvirt/qemu - persistent modification of devices.
> 
> Now, qemudDomainAttachDeviceFlags() and qemudDomainDetachDeviceFlags()
> doesn't support VIR_DOMAIN_DEVICE_MODIFY_CONFIG. By this, virsh's
> at(de)tatch-device --persistent cannot modify qemu config.
> (Xen allows it.)
> 
> This patch is a base patch for adding support of devices in
> step by step manner. Following patches will add some device
> support.
> 
> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu at jp.fujitsu.com>
> ---
>  src/qemu/qemu_driver.c |  138 +++++++++++++++++++++++++++++++++++++++++++-----
>  1 files changed, 125 insertions(+), 13 deletions(-)
> 
> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
> index af897ad..a4fb1cd 100644
> --- a/src/qemu/qemu_driver.c
> +++ b/src/qemu/qemu_driver.c
> @@ -4144,16 +4144,125 @@ cleanup:
>      return ret;
>  }
>  
> -static int qemudDomainAttachDeviceFlags(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"));
> +/*
> + * 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)
> +{
> +
> +    switch(newdev->type) {
> +    default:
> +        qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
> +                        _("Sorry, the device is not supported for now"));
> +        return -1;
> +    }
> +
> +    return 0;
> +}
> +
> +static int qemuDomainDetachDevicePersistent(virDomainDefPtr vmdef,
> +                                            virDomainDeviceDefPtr device)
> +{
> +    switch(device->type) {
> +    default:
> +        qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
> +                        _("Sorry, the device is not supported for now"));
>          return -1;
>      }
> +    return 0;
> +}
> +
> +static int qemuDomainModifyDevicePersistent(virDomainPtr dom,
> +                                            const char *xml,
> +                                            unsigned int attach,
> +                                            unsigned int flags)
> +{
> +    struct qemud_driver *driver;
> +    virDomainDeviceDefPtr device;
> +    virDomainDefPtr vmdef;
> +    virDomainObjPtr vm;
> +    int ret = -1;
> +
> +    /*
> +     * When both of MODIFY_CONFIG and MODIFY_LIVE is specified at the same,
> +     * time return error for now. We should support this later.

s/at the same, time/at the same time,/

> +     */
> +    if (flags & VIR_DOMAIN_DEVICE_MODIFY_LIVE) {
> +        qemuReportError(VIR_ERR_OPERATION_INVALID, "%s",
> +                        _("Now, cannot modify alive domain and its definition "

You use 'alive domain' here, but you use 'active domain' below.
The message should be consistent.

> +                          "at the same time."));
> +        return -1;
> +    }
> +
> +    driver = dom->conn->privateData;
> +    qemuDriverLock(driver);
> +    vm = virDomainFindByName(&driver->domains, dom->name);
> +    if (!vm) {
> +        qemuReportError(VIR_ERR_NO_DOMAIN, _("no domain with name : '%s'"),
> +                        dom->name);
> +        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",
> +                        _("unsupported to update active domain's definition."));
> +        goto endjob;
> +    }
> +
> +    vmdef = virDomainObjGetPersistentDef(driver->caps, vm);
>  
> -    return qemudDomainAttachDevice(dom, xml);
> +    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);

vmdef may be modified even if ret is not 0, but you do not update
the xml file. I do not find any problem about this, but it may be
better to update the xml file when ret is not 0.

> +
> +    virDomainDeviceDefFree(device);
> +
> +endjob:
> +    if (qemuDomainObjEndJob(vm) == 0)
> +        vm = NULL;
> +unlock_out:
> +    if (vm)
> +        virDomainObjUnlock(vm);
> +    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 not supported"), flags);

If the flags is VIR_DOMAIN_DEVICE_MODIFY_LIVE | unsupported_flags, we do not
report error here.

You can use the macro virCheckFlags to check it.

> +
> +    return -1;
>  }
>  
>  
> @@ -4368,13 +4477,16 @@ 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 not supported now"), flags);
> +    return -1;

the same as above

>  }
>  
>  static int qemudDomainGetAutostart(virDomainPtr dom,