Re: [Qemu-devel] [PATCH V3 06/11] qmp: add interface query-images.

[Luiz Capitulino <lcapitulino@redhat.com>]

On Mon, 14 Jan 2013 15:09:42 +0800
Wenchao Xia <xiawenc@linux.vnet.ibm.com> wrote:

>   This mirror function will return all image info including
> snapshots. Now Qemu have both query-images and query-block
> interfaces.
> 
> Signed-off-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
> ---
>  block.c          |   19 +++++++++++++
>  qapi-schema.json |   27 +++++++++++++++++++
>  qmp-commands.hx  |   76 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 122 insertions(+), 0 deletions(-)
> 
> diff --git a/block.c b/block.c
> index 502c06e..8192d8e 100644
> --- a/block.c
> +++ b/block.c
> @@ -2963,6 +2963,25 @@ ImageInfo *bdrv_query_image_info(BlockDriverState *bs, Error **errp)
>      return info;
>  }
>  
> +DeviceImageInfoList *qmp_query_images(Error **errp)
> +{
> +    DeviceImageInfoList *head = NULL, **p_next = &head;
> +    BlockDriverState *bs;
> +
> +    QTAILQ_FOREACH(bs, &bdrv_states, list) {
> +        DeviceImageInfo *dii = g_malloc0(sizeof(*dii));
> +        dii->device = g_strdup(bs->device_name);
> +        dii->info = bdrv_query_image_info(bs, NULL);
> +        DeviceImageInfoList *diil = g_malloc0(sizeof(*diil));
> +        diil->value = dii;
> +
> +        *p_next = diil;
> +        p_next = &diil->next;
> +    }

When the device doesn't have an image, this returns:

        {
            "device": "ide1-cd0", 
            "info": {
                "virtual-size": 0, 
                "filename": "", 
                "format": ""
            }
        },

But it would be better to return an empty dict or even omit 'info'
completely. One more comment below.

> +
> +    return head;
> +}
> +
>  BlockInfo *bdrv_query_block_info(BlockDriverState *bs)
>  {
>      BlockInfo *info = g_malloc0(sizeof(*info));
> diff --git a/qapi-schema.json b/qapi-schema.json
> index 5dfa052..565737c 100644
> --- a/qapi-schema.json
> +++ b/qapi-schema.json
> @@ -245,6 +245,22 @@
>             '*backing-filename-format': 'str', '*snapshots': ['SnapshotInfo'] } }
>  
>  ##
> +# @DeviceImageInfo:
> +#
> +# Information about an image used by QEMU block device
> +#
> +# @device: name of the block device
> +#
> +# @info: info of the image used.

Info is too generic, please call it 'image'.

> +#
> +# Since: 1.4
> +#
> +##
> +
> +{ 'type': 'DeviceImageInfo',
> +  'data': {'device': 'str', 'info': 'ImageInfo' } }
> +
> +##
>  # @StatusInfo:
>  #
>  # Information about VCPU run state
> @@ -720,6 +736,17 @@
>  { 'command': 'query-block', 'returns': ['BlockInfo'] }
>  
>  ##
> +# @query-images:
> +#
> +# Get a list of DeviceImageInfo for all virtual block devices.
> +#
> +# Returns: a list of @DeviceImageInfo describing each virtual block device
> +#
> +# Since: 1.4
> +##
> +{ 'command': 'query-images', 'returns': ['DeviceImageInfo'] }
> +
> +##
>  # @BlockDeviceStats:
>  #
>  # Statistics of a virtual block device or a block backing device.
> diff --git a/qmp-commands.hx b/qmp-commands.hx
> index 5c692d0..c31a142 100644
> --- a/qmp-commands.hx
> +++ b/qmp-commands.hx
> @@ -1668,6 +1668,82 @@ EQMP
>      },
>  
>  SQMP
> +query-images
> +-----------
> +
> +Show the block devices' images.
> +
> +Each block image information is stored in a json-object and the returned value
> +is a json-array of all devices' images.
> +
> +Each json-object contain the following:
> +
> +- "device": device name (json-string)
> +- "info": related image information, it is a json-object containing the following:
> +         - "filename": image file name (json-string)
> +         - "format": image format (json-string)
> +         - "virtual-size": maximum capacity in bytes of the image (json-int)
> +         - "dirty-flag": true if image is not cleanly closed (json-bool, optional)
> +         - "actual-size": actual size on disk in bytes of the image (json-int, optional)
> +         - "cluster-size": size of a cluster in bytes (json-int, optional)
> +         - "encrypted": true if the image is encrypted (json-bool, optional)
> +         - "backing_file": backing file name (json-string, optional)
> +         - "full-backing-filename": full path of the backing file (json-string, optional)
> +         - "backing-filename-format": the format of the backing file (json-string, optional)
> +         - "snapshots": the internal snapshot info, it is an optional list of json-object
> +            containing the following:
> +             - "id": unique snapshot id (json-string)
> +             - "name": internal snapshot name (json-string)
> +             - "vm-state-size": size of the VM state in bytes (json-int)
> +             - "date-sec": UTC date of the snapshot in seconds (json-int)
> +             - "date-nsec": fractional part in nano seconds to be used with date-sec(json-int)
> +             - "vm-clock-sec": VM clock relative to boot in seconds (json-int)
> +             - "vm-clock-nsec": fractional part in nano seconds to be used with vm-clock-sec (json-int)
> +
> +Example:
> +
> +-> { "execute": "query-images" }
> +<- {
> +      "return":[
> +         {
> +            "device":"ide0-hd0",
> +            "info":{
> +               "filename":"disks/test0.img",
> +               "format":"qcow2",
> +               "virtual-size":1024000
> +            }
> +         },
> +         {
> +            "device":"ide0-hd1",
> +            "info":{
> +               "filename":"disks/test1.img",
> +               "format":"qcow2",
> +               "virtual-size":2048000,
> +               "snapshots":[
> +                  {
> +                     "id": "1",
> +                     "name": "snapshot1",
> +                     "vm-state-size": 0,
> +                     "date-sec": 10000200,
> +                     "date-nsec": 12,
> +                     "vm-clock-sec": 206,
> +                     "vm-clock-nsec": 30
> +                  }
> +               ]
> +            }
> +         }
> +      ]
> +   }
> +
> +EQMP
> +
> +    {
> +        .name       = "query-images",
> +        .args_type  = "",
> +        .mhandler.cmd_new = qmp_marshal_input_query_images,
> +    },
> +
> +SQMP
>  query-blockstats
>  ----------------
>