[libvirt] [PATCH v1 04/11] qemu: Introduce nbd-server-add command

[Michal Privoznik]

On 28.11.2012 00:41, Eric Blake wrote:
>> This will be used with new migration scheme.
>> This patch creates basically just monitor stub
>> functions. Wiring them into something useful
>> is done in later patches.
>> ---
>>  src/qemu/qemu_monitor.c      |   21 +++++++++++++++++++++
>>  src/qemu/qemu_monitor.h      |    2 ++
>>  src/qemu/qemu_monitor_json.c |   23 +++++++++++++++++++++++
>>  src/qemu/qemu_monitor_json.h |    2 ++
>>  4 files changed, 48 insertions(+), 0 deletions(-)
>>
> 
>> +
>> +int
>> +qemuMonitorJSONNBDServerAdd(qemuMonitorPtr mon,
>> +                            const char *deviceID)
>> +{
>> +    int ret = -1;
>> +    virJSONValuePtr cmd;
>> +    virJSONValuePtr reply = NULL;
>> +
>> +    if (!(cmd = qemuMonitorJSONMakeCommand("nbd-server-add",
>> +                                           "s:device", deviceID,
>> +                                           NULL)))
> 
> According to qemu.git, 'writable' is optional, but if omitted, it
> defaults to false.  But doesn't storage migration require 'writable'
> to be true in order for drive-mirror on the source to be able to
> actually write into the destination?
> 
> [You may have dealt with this later in the series, but even if so,
> I still think this stub should be doing something with "b:writable".]
> 

Ah, there's a bug in qemu; qapi-schema.json tells the default is false,
however blockdev-nbd.c sets default to false. That would explain why it
worked even without explicitly setting this argument.

Anyway, I'll update my patch. Meanwhile, I've posted a qemu patch:

http://lists.nongnu.org/archive/html/qemu-devel/2012-11/msg03133.html

Michal