[libvirt] ambiguous ret of qemuDomainDetachVirtioDiskDevice

zhang bo oscar.zhangbo at huawei.com
Tue Jul 28 08:25:13 UTC 2015

static int
qemuDomainDetachVirtioDiskDevice(virQEMUDriverPtr driver,
                                 virDomainObjPtr vm,
                                 virDomainDiskDefPtr detach)

    rc = qemuDomainWaitForDeviceRemoval(vm);
    if (rc == 0 || rc == 1)
        ret = qemuDomainRemoveDiskDevice(driver, vm, detach);
        ret = 0;  /*the return value of 2 is dismissed here, which refers to ETIMEOUT.*/


If it timeouts when qemu tries to del the device, the return value would be modified from 2 to 0 in 
function qemuDomainDetachVirtioDiskDevice(), which means that, the users would be misleaded that 
the device has been deleted, however, the device maybe probably failed to be detached after timeout and
still in use. 

That is to say, the function qemuDomainDetachVirtioDiskDevice()'s return value is ambiguous when it's 0, 
maybe successful, or timeout. Will it be better to pass ETIMEOUT to user? or any other advises? for example,
let users themselves dumpxml the guest to check whether the device has been actually detached or not? 

oscar.zhangbo at huawei.com  

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