[libvirt] [PATCH v2] xen: Prevent updating device when attaching a device

[Osier Yang]

于 2011年02月10日 14:09, Daniel Veillard 写道:
> On Wed, Feb 09, 2011 at 02:01:25PM +0000, Daniel P. Berrange wrote:
>> On Wed, Feb 09, 2011 at 04:51:27PM +0800, Osier Yang wrote:
>>> When attaching a device that already exists, xend driver updates
>>> the device with "device_configure", it causes problems (e.g. for
>>> disk device, 'device_configure' only can be used to update device
>>> like CDROM), on the other hand, we provide additional API
>>> (virDomainUpdateDevice) to update device, this fix is to raise up
>>> errors instead of updating the existed device which is not CDROM
>>> device.
>>>
>>> Changes from v1 to v2:
>>>    - allow update CDROM
>>>
>>> * src/xen/xend_internal.c
>>> ---
>>>   src/xen/xend_internal.c |   42 +++++++++++++++++++++++++++++++++++++-----
>>>   1 files changed, 37 insertions(+), 5 deletions(-)
>>
>>
>>
>>>
>>> diff --git a/src/xen/xend_internal.c b/src/xen/xend_internal.c
>>> index cd30336..bc23595 100644
>>> --- a/src/xen/xend_internal.c
>>> +++ b/src/xen/xend_internal.c
>>> @@ -3965,6 +3965,7 @@ xenDaemonAttachDeviceFlags(virDomainPtr domain, const char *xml,
>>>       virDomainDefPtr def = NULL;
>>>       virBuffer buf = VIR_BUFFER_INITIALIZER;
>>>       char class[8], ref[80];
>>> +    char *target = NULL;
>>>
>>>       if ((domain == NULL) || (domain->conn == NULL) || (domain->name == NULL)) {
>>>           virXendError(VIR_ERR_INVALID_ARG, __FUNCTION__);
>>> @@ -4029,6 +4030,13 @@ xenDaemonAttachDeviceFlags(virDomainPtr domain, const char *xml,
>>>                                       STREQ(def->os.type, "hvm") ? 1 : 0,
>>>                                       priv->xendConfigVersion, 1)<  0)
>>>               goto cleanup;
>>> +
>>> +        if (dev->data.disk->device != VIR_DOMAIN_DISK_DEVICE_CDROM) {
>>
>> I can't remember if Xen supports it or not, but do we need  DEVICE_FLOPPY
>> here too ?
>
>    I would guess that yes, we use it in the xend driver
>
>> The patch looks good aside from that question
>
> Daniel
>

Checked xend's code, from the code, floppy device updating is not
supported, and also tried to update a floppy device via "xm",
that's true.

file: "xend/server/blkif.py"

     def reconfigureDevice(self, _, config):
         """@see DevController.reconfigureDevice"""
         (devid, new_back, new_front) = self.getDeviceDetails(config)

         (dev, mode) = self.readBackend(devid, 'dev', 'mode')
         dev_type = self.readFrontend(devid, 'device-type')

         if (dev_type == 'cdrom' and new_front['device-type'] == 'cdrom' and
             dev == new_back['dev'] and mode == 'r'):

             if not os.access(new_back['params'],os.R_OK):
                 raise VmError("Can't read disk file %s" % 
new_back['params'])

             self.writeBackend(devid,
                               'type', new_back['type'],
                               'params', new_back['params'])
         else:
             raise VmError('Refusing to reconfigure device %s:%d to %s' %
                           (self.deviceClass, devid, config))


[root at dhcp exp]# xm block-list RHEL5-hvm-64
Vdev  BE handle state evt-ch ring-ref BE-path
51712    0    0     1      -1     -1 
/local/domain/0/backend/tap/18/51712
4058    0    0     1      -1     -1    /local/domain/0/backend/vbd/18/4058

[root at dhcp- exp]# xm block-configure 18 
file:/var/lib/xen/images/floppy.img fda:floppy r
Error: Refusing to reconfigure device vbd:4058 to ['vbd', ['uname', 
'file:/var/lib/xen/images/floppy.img'], ['dev', 'fda:floppy'], ['mode', 
'r']]


so I will push the patch.

Regards
Osier