[libvirt] [PATCHv8 1/4] libvirt/qemu - persistent modification of inactive domans.

[Wen Congyang]

At 04/01/2011 12:17 PM, KAMEZAWA Hiroyuki Write:
>>From 1ffbe73b1663719414367abbdebc8f31b9592331 Mon Sep 17 00:00:00 2001
> From: KAMEZAWA Hiroyuki <kamezawa.hiroyu at jp.fujitsu.com>
> Date: Thu, 31 Mar 2011 16:20:05 +0900
> Subject: [PATCHv8 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 |  150 +++++++++++++++++++++++++++++++++++++++++++-----
>  1 files changed, 136 insertions(+), 14 deletions(-)
> 
> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
> index dd12dc8..b89bc8f 100644
> --- a/src/qemu/qemu_driver.c
> +++ b/src/qemu/qemu_driver.c
> @@ -3873,16 +3873,133 @@ 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"));
> +/*
> + * At(de)tach a device given by XML, the change will be persistent
> + * and domain XML definition file is updated when these function
> + * returns 0(success). IOW, at failure, XML definition is never updated.
> + * So, this function must guarantee consistency between vmdef and its XML
> + * definition in the file.
> + */
> +
> +static int qemuDomainAttachDevicePersistent(virDomainDefPtr vmdef,
> +                                            virDomainDeviceDefPtr newdev)
> +{
> +
> +    switch(newdev->type) {
> +    default:
> +        qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
> +                        _("the device is not supported for now"));
>          return -1;
>      }
>  
> -    return qemudDomainAttachDevice(dom, xml);
> +    return 0;
> +}
> +
> +static int qemuDomainDetachDevicePersistent(virDomainDefPtr vmdef,
> +                                            virDomainDeviceDefPtr device)
> +{
> +    switch(device->type) {
> +    default:
> +        qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
> +                        _("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 are passed at the same time,
> +     * return error for now. We should support this later.
> +     */
> +    if (flags & VIR_DOMAIN_DEVICE_MODIFY_LIVE) {
> +        qemuReportError(VIR_ERR_OPERATION_INVALID, "%s",
> +                        _("cannot modify active domain and its definition "
> +                          "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",
> +                        _("cannot modify 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);
> +    /*
> +     * At(De)tachDevicePersistent() must guarantee that vmdef is consistent
> +     * with XML definition when they returns a failure, ret != 0.
> +     */

This comment can be removed in patch 2 as we use a copy of XML definition.

> +    if (!ret)
> +        ret = virDomainSaveConfig(driver->configDir, vmdef);
> +
> +    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)
> +{
> +    int ret = -1;
> +
> +    virCheckFlags((VIR_DOMAIN_DEVICE_MODIFY_CONFIG |
> +                   VIR_DOMAIN_DEVICE_MODIFY_LIVE), -1);
> +
> +    if (flags & VIR_DOMAIN_DEVICE_MODIFY_CONFIG)
> +        ret = qemuDomainModifyDevicePersistent(dom, xml, 1, flags);
> +    else if (flags & VIR_DOMAIN_DEVICE_MODIFY_LIVE)
> +        ret = qemudDomainAttachDevice(dom, xml);
> +
> +    return ret;
>  }
>  
>  
> @@ -4096,14 +4213,19 @@ 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;
> -    }
> +                                        unsigned int flags)
> +{
> +    int ret = -1;
> +
> +    virCheckFlags((VIR_DOMAIN_DEVICE_MODIFY_CONFIG |
> +                   VIR_DOMAIN_DEVICE_MODIFY_LIVE), -1);
>  
> -    return qemudDomainDetachDevice(dom, xml);
> +    if (flags & VIR_DOMAIN_DEVICE_MODIFY_CONFIG)
> +        ret = qemuDomainModifyDevicePersistent(dom, xml, 0, flags);
> +    else if (flags & VIR_DOMAIN_DEVICE_MODIFY_LIVE)
> +        ret = qemudDomainDetachDevice(dom, xml);
> +
> +    return ret;
>  }
>  
>  static int qemudDomainGetAutostart(virDomainPtr dom,