Re: [Qemu-devel] [V5 Patch 1/4]Qemu: Enhance "info block" to display host cache setting

[Supriya Kannery <supriyak@in.ibm.com>]

On 07/27/2011 07:49 PM, Stefan Hajnoczi wrote:
> On Wed, Jul 27, 2011 at 12:30 PM, Supriya Kannery
> <supriyak@linux.vnet.ibm.com>  wrote:
>> Enhance "info block" to display hostcache setting for each
>> block device.
>>
>> Example:
>> (qemu) info block
>> ide0-hd0: type=hd removable=0 file=../rhel6-32.qcow2 ro=0 drv=qcow2
>> encrypted=0
>>
>> Enhanced to display "hostcache" setting:
>> (qemu) info block
>> ide0-hd0: type=hd removable=0 hostcache=true file=../rhel6-32.qcow2
>> ro=0 drv=qcow2 encrypted=0
>
> This description is outdated, should be hostcache=1 instead of hostcache=true.
>
>> @@ -1749,13 +1757,18 @@ void bdrv_info(Monitor *mon, QObject **r
>>          QObject *bs_obj;
>>
>>          bs_obj = qobject_from_jsonf("{ 'device': %s, 'type': 'unknown', "
>> -                                    "'removable': %i, 'locked': %i }",
>> -                                    bs->device_name, bs->removable,
>> -                                    bs->locked);
>> +                                     "'removable': %i, 'locked': %i, "
>> +                                     "'hostcache': %s }",
>> +                                     bs->device_name, bs->removable,
>> +                                     bs->locked,
>> +                                     (bs->open_flags&  BDRV_O_NOCACHE) ?
>> +                                     "false" : "true");
>
> Please use the same bool-from-int format specifier ('%i') as the other
> fields for consistency.  The value can be !(bs->open_flags&
> BDRV_O_NOCACHE).
>

ok

>> +
>> +        QDict *bs_dict = qobject_to_qdict(bs_obj);
>> +        qdict_put(bs_dict, "open_flags", qint_from_int(bs->open_flags));
>>
>>          if (bs->drv) {
>>              QObject *obj;
>> -            QDict *bs_dict = qobject_to_qdict(bs_obj);
>>
>>              obj = qobject_from_jsonf("{ 'file': %s, 'ro': %i, 'drv': %s, "
>>                                       "'encrypted': %i }",
>
> My copy of the code has the following a few lines further down:
> qdict_put_obj(bs_dict, "inserted", obj);
>
> Removing bs_dict would break the build.  Am I missing something?
>

qdict_put_obj() for "inserted" is still there further down in the code.
Here,
   QDict *bs_dict = qobject_to_qdict(bs_obj);
is moved up to enable placing of "open_flags" into the dict. We need 
"open_flags" in dict to calculate hostcache value for printing in
monitor. Code for placing "inserted" is not touched.

>> Index: qemu/qmp-commands.hx
>> ===================================================================
>> --- qemu.orig/qmp-commands.hx
>> +++ qemu/qmp-commands.hx
>> @@ -1131,6 +1131,7 @@ Each json-object contain the following:
>>           - Possible values: "unknown"
>>   - "removable": true if the device is removable, false otherwise (json-bool)
>>   - "locked": true if the device is locked, false otherwise (json-bool)
>> +- "hostcache": true if hostcache enabled, false otherwise (json-bool)
>
> Let's explain what "hostcache" means:
>
> - "hostcache": true if host page cache is enabled, false otherwise (json-bool)
>

ok

-Thanks, Supriya

> Stefan