Patchwork [V6,08/14] qmp: add interface query-images.

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Submitter Wayne Xia
Date Feb. 18, 2013, 2:09 p.m.
Message ID <1361196578-19016-9-git-send-email-xiawenc@linux.vnet.ibm.com>
Download mbox | patch
Permalink /patch/221400/
State New
Headers show

Comments

Wayne Xia - Feb. 18, 2013, 2:09 p.m.
This mirror function will return all image info including
snapshots, if specified backing image's info will also be returned.
Now Qemu have both query-images and query-block interfaces.

Signed-off-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
---
 block.c          |   83 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 qapi-schema.json |   35 ++++++++++++++++++++++
 qmp-commands.hx  |   76 +++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 194 insertions(+), 0 deletions(-)
Eric Blake - Feb. 20, 2013, 6:25 p.m.
On 02/18/2013 07:09 AM, Wenchao Xia wrote:
>   This mirror function will return all image info including
> snapshots, if specified backing image's info will also be returned.
> Now Qemu have both query-images and query-block interfaces.
> 
> Signed-off-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
> ---
>  block.c          |   83 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  qapi-schema.json |   35 ++++++++++++++++++++++
>  qmp-commands.hx  |   76 +++++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 194 insertions(+), 0 deletions(-)
> 

> +++ b/qapi-schema.json
> @@ -245,6 +245,22 @@
>             '*backing-filename-format': 'str', '*snapshots': ['SnapshotInfo'] } }
>  
>  ##
> +# @DeviceImageInfo:
> +#
> +# Information about an image used by QEMU block device

s/by/by a/

> +#
> +# @device: name of the block device
> +#
> +# @image: #optional info of the image used.

Not consistent on whether there is a trailing '.' (looks like most
one-line docstrings don't have one, but it is not a hard rule)

>  
>  ##
> +# @query-images:
> +#
> +# Get a list of DeviceImageInfo for all virtual block devices.
> +#
> +# @device: #optional the name of the device to get image info from. If not
> +#          specified, all block devices's image info would be returned.

s/devices's image info would be returned/devices will be queried/

> +# @backing: #optional whether show info of backing images if they exist. If not
> +#          specified, only the top image info of the block devices would be
> +#          returned.

A bit verbose; I'd suggest:

@backing: #optional true to show information on backing images, false or
omitted to show just the top image of a block device

> +#
> +# Returns: a list of @DeviceImageInfo describing each virtual block device
> +#
> +# Since: 1.5
> +##
> +{ 'command': 'query-images',
> +  'data': { '*device': 'str', '*backing': 'bool' },
> +  'returns': ['DeviceImageInfo'] }
> +
> +##

At any rate, I like how the interface has turned out, when my only
comments are regarding grammar of the documentation.

Patch

diff --git a/block.c b/block.c
index a1c24dc..480e8c6 100644
--- a/block.c
+++ b/block.c
@@ -2959,6 +2959,89 @@  ImageInfo *bdrv_query_image_info(BlockDriverState *bs, Error **errp)
     return info;
 }
 
+/* collect all info for one bs, p_list point to the empty tail to be filled,
+   return the empty tail of the new list. */
+static DeviceImageInfoList **
+collect_device_image_info_list(BlockDriverState *bs,
+                               bool show_backing,
+                               DeviceImageInfoList **p_list,
+                               Error **errp)
+{
+    DeviceImageInfoList **p_next = p_list;
+
+    while (bs) {
+        DeviceImageInfo *dii = g_malloc0(sizeof(*dii));
+        DeviceImageInfoList *diil = g_malloc0(sizeof(*diil));
+        diil->value = dii;
+        *p_next = diil;
+        p_next = &diil->next;
+
+        dii->device = g_strdup(bs->device_name);
+        if (!bdrv_is_inserted(bs)) {
+            dii->has_image = false;
+            break;
+        }
+        dii->has_image = true;
+        dii->image = bdrv_query_image_info(bs, errp);
+        if (error_is_set(errp)) {
+            break;
+        }
+
+        if (show_backing && bs->drv && bs->backing_hd) {
+            bs = bs->backing_hd;
+        } else {
+            bs = NULL;
+        }
+    }
+    return p_next;
+}
+
+DeviceImageInfoList *qmp_query_images(bool has_device,
+                                      const char *device,
+                                      bool has_backing,
+                                      bool backing,
+                                      Error **errp)
+{
+    DeviceImageInfoList *head = NULL, **p_next = &head;
+    BlockDriverState *bs = NULL;
+    Error *err = NULL;
+    const char *target_device = NULL;
+    bool show_backing = false;
+
+    if (has_device) {
+        target_device = device;
+    }
+    if (has_backing) {
+        show_backing = backing;
+    }
+
+    if (target_device) {
+        bs = bdrv_find(device);
+        if (!bs) {
+            error_set(errp, QERR_DEVICE_NOT_FOUND, device);
+            return NULL;
+        }
+        collect_device_image_info_list(bs, show_backing, p_next, errp);
+        if (error_is_set(&err)) {
+            goto err;
+        }
+    } else {
+        QTAILQ_FOREACH(bs, &bdrv_states, list) {
+            p_next = collect_device_image_info_list(bs, show_backing,
+                                                    p_next, errp);
+            if (error_is_set(&err)) {
+                goto err;
+            }
+        }
+    }
+
+    return head;
+
+ err:
+    qapi_free_DeviceImageInfoList(head);
+    return NULL;
+}
+
 BlockInfo *bdrv_query_block_info(BlockDriverState *bs)
 {
     BlockInfo *info = g_malloc0(sizeof(*info));
diff --git a/qapi-schema.json b/qapi-schema.json
index 7275b5d..70777c0 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
+#
+# @image: #optional info of the image used.
+#
+# Since: 1.5
+#
+##
+
+{ 'type': 'DeviceImageInfo',
+  'data': {'device': 'str', '*image': 'ImageInfo' } }
+
+##
 # @StatusInfo:
 #
 # Information about VCPU run state
@@ -789,6 +805,25 @@ 
 { 'command': 'query-block', 'returns': ['BlockInfo'] }
 
 ##
+# @query-images:
+#
+# Get a list of DeviceImageInfo for all virtual block devices.
+#
+# @device: #optional the name of the device to get image info from. If not
+#          specified, all block devices's image info would be returned.
+# @backing: #optional whether show info of backing images if they exist. If not
+#          specified, only the top image info of the block devices would be
+#          returned.
+#
+# Returns: a list of @DeviceImageInfo describing each virtual block device
+#
+# Since: 1.5
+##
+{ 'command': 'query-images',
+  'data': { '*device': 'str', '*backing': 'bool' },
+  '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 799adea..292d61e 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -1743,6 +1743,82 @@  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)
+- "image": related image information, it is a optional 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",
+            "image":{
+               "filename":"disks/test0.img",
+               "format":"qcow2",
+               "virtual-size":1024000
+            }
+         },
+         {
+            "device":"ide0-hd1",
+            "image":{
+               "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  = "device:B?, backing:-b",
+        .mhandler.cmd_new = qmp_marshal_input_query_images,
+    },
+
+SQMP
 query-blockstats
 ----------------