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

[Stefan Hajnoczi <stefanha@gmail.com>]

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This description is outdated, should be hostcache=1 instead of hostcache=true.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).

> +
> +        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?

> 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)

Stefan