[libvirt] [PATCH] Fix ejecting cdroms with latest qemu syntax

[Cole Robinson]

Daniel P. Berrange wrote:
> On Mon, Aug 25, 2008 at 01:41:24PM -0400, Cole Robinson wrote:
>> +
>> +    int idx = virDiskNameToIndex(newdisk->dst);
>> +    switch (newdisk->bus) {
>> +        /* Assume that if we are here, device targets don't exceed hypervisor
>> +         * limits, and we are already an appropriate device type */
>> +        case VIR_DOMAIN_DISK_BUS_IDE:
>> +            /* Device name of the form 'ide{0-1}-cd{0-1}' */
>> +            ret = asprintf(&devname, "ide%d-cd%d", ((idx - (idx % 2)) / 2),
>> +                                                   (idx % 2));
>> +            break;
>> +        case VIR_DOMAIN_DISK_BUS_SCSI:
>> +            /* Device name of the form 'scsi{bus#}-cd{0-6}
>> +             * Each bus holds seven devs */
>> +            ret = asprintf(&devname, "scsi%d-cd%d", ((idx - (idx % 7)) / 7),
>> +                                                    (idx % 7));
>> +            break;
>> +        case VIR_DOMAIN_DISK_BUS_FDC:
>> +            /* Device name is 'floppy{0-1}' */
>> +            ret = asprintf(&devname, "floppy%d", idx);
>> +            break;
>> +
>> +        default:
>> +            qemudReportError(dom->conn, dom, NULL, VIR_ERR_NO_SUPPORT,
>> +                             _("Cannot hotplug device with bus '%s'"),
>> +                             virDomainDiskBusTypeToString(newdisk->bus));
>> +            return -1;
>> +    }
> 
> I think this block could be re-factored a little into one or more helper
> methods, because I think we'll need to re-use this for hot-unplug of
> disks. I'd suggest a helper to turn the plain integer index into the
> (bus,device) index pair
> 
>      virDiskNameToBusDeviceIndex(virDomainDiskDefPtr disk, 
>                                  int *busIdx, 
>                                  int *devIdx);
> 
> And then a QEMU specific function
> 
>     char *virQEMUDeviceName(virDomainDiskDefPtr disk);
> 
> and have this call virDiskNameToBusDeviceIndex() and return the 'ide1-2'
> type string.
> 

Okay, second cut attached. I followed your recommendations:

virDiskNameToBusDeviceIndex added to domain_conf.c
qemudDiskDeviceName added to qemu_driver.c

I also hopefully solved the back compatibility issue. Seems
-drive was added to qemu in Dec 07 (qemu commit 3759) and the
device naming scheme was updated at the end of that month (qemu
commit 3846), so checking for -drive should be a sufficient 
indicator that we need to use the new device name format. So
if drive was detected (using the already present qemu_conf
flag), we revert to the old style cdrom/fda naming style.

I tested this on f8 using plain qemu (which lacks the -drive
option) and it appeared to work as expected for cdrom and
floppy devices.

Thanks,
Cole


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