qmp: add ImageInfo in BlockDeviceInfo used by query-block

Now image info will be retrieved as an embbed json object inside
BlockDeviceInfo, backing chain info and all related internal snapshot
info can be got in the enhanced recursive structure of ImageInfo. New
recursive member *backing-image is added to reflect the backing chain
status.

Signed-off-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

block/qapi.c

@@ -94,6 +94,13 @@ int bdrv_query_snapshot_info_list(BlockDriverState *bs,
  * @p_info: location to store image information
  * @errp: location to store error information
  *
+ * Store "flat" image information in @p_info.
+ *
+ * "Flat" means it does *not* query backing image information,
+ * i.e. (*pinfo)->has_backing_image will be set to false and
+ * (*pinfo)->backing_image to NULL even when the image does in fact have
+ * a backing image.
+ *
  * @p_info will be set only on success. On error, store error in @errp.
  */
 void bdrv_query_image_info(BlockDriverState *bs,
@@ -167,9 +174,15 @@ void bdrv_query_image_info(BlockDriverState *bs,
     *p_info = info;
 }
 
-BlockInfo *bdrv_query_info(BlockDriverState *bs)
+/* @p_info will be set only on success. */
+void bdrv_query_info(BlockDriverState *bs,
+                     BlockInfo **p_info,
+                     Error **errp)
 {
     BlockInfo *info = g_malloc0(sizeof(*info));
+    BlockDriverState *bs0;
+    ImageInfo **p_image_info;
+    Error *local_err = NULL;
     info->device = g_strdup(bs->device_name);
     info->type = g_strdup("unknown");
     info->locked = bdrv_dev_is_medium_locked(bs);
@@ -223,8 +236,30 @@ BlockInfo *bdrv_query_info(BlockDriverState *bs)
             info->inserted->iops_wr =
                            bs->io_limits.iops[BLOCK_IO_LIMIT_WRITE];
         }
+
+        bs0 = bs;
+        p_image_info = &info->inserted->image;
+        while (1) {
+            bdrv_query_image_info(bs0, p_image_info, &local_err);
+            if (error_is_set(&local_err)) {
+                error_propagate(errp, local_err);
+                goto err;
+            }
+            if (bs0->drv && bs0->backing_hd) {
+                bs0 = bs0->backing_hd;
+                (*p_image_info)->has_backing_image = true;
+                p_image_info = &((*p_image_info)->backing_image);
+            } else {
+                break;
+            }
+        }
     }
-    return info;
+
+    *p_info = info;
+    return;
+
+ err:
+    qapi_free_BlockInfo(info);
 }
 
 BlockStats *bdrv_query_stats(const BlockDriverState *bs)
@@ -261,16 +296,25 @@ BlockInfoList *qmp_query_block(Error **errp)
 {
     BlockInfoList *head = NULL, **p_next = &head;
     BlockDriverState *bs = NULL;
+    Error *local_err = NULL;
 
      while ((bs = bdrv_next(bs))) {
         BlockInfoList *info = g_malloc0(sizeof(*info));
-        info->value = bdrv_query_info(bs);
+        bdrv_query_info(bs, &info->value, &local_err);
+        if (error_is_set(&local_err)) {
+            error_propagate(errp, local_err);
+            goto err;
+        }
 
         *p_next = info;
         p_next = &info->next;
     }
 
     return head;
+
+ err:
+    qapi_free_BlockInfoList(head);
+    return NULL;
 }
 
 BlockStatsList *qmp_query_blockstats(Error **errp)

include/block/qapi.h

@@ -35,7 +35,9 @@ int bdrv_query_snapshot_info_list(BlockDriverState *bs,
 void bdrv_query_image_info(BlockDriverState *bs,
                            ImageInfo **p_info,
                            Error **errp);
-BlockInfo *bdrv_query_info(BlockDriverState *s);
+void bdrv_query_info(BlockDriverState *bs,
+                     BlockInfo **p_info,
+                     Error **errp);
 BlockStats *bdrv_query_stats(const BlockDriverState *bs);
 
 void bdrv_snapshot_dump(fprintf_function func_fprintf, void *f,

qapi-schema.json

@@ -236,6 +236,8 @@
 #
 # @snapshots: #optional list of VM snapshots
 #
+# @backing-image: #optional info of the backing image (since 1.6)
+#
 # Since: 1.3
 #
 ##
@@ -245,7 +247,8 @@
            '*actual-size': 'int', 'virtual-size': 'int',
            '*cluster-size': 'int', '*encrypted': 'bool',
            '*backing-filename': 'str', '*full-backing-filename': 'str',
-           '*backing-filename-format': 'str', '*snapshots': ['SnapshotInfo'] } }
+           '*backing-filename-format': 'str', '*snapshots': ['SnapshotInfo'],
+           '*backing-image': 'ImageInfo' } }
 
 ##
 # @ImageCheck:
@@ -756,6 +759,8 @@
 #
 # @iops_wr: write I/O operations per second is specified
 #
+# @image: the info of image used (since: 1.6)
+#
 # Since: 0.14.0
 #
 # Notes: This interface is only found in @BlockInfo.
@@ -765,7 +770,8 @@
             '*backing_file': 'str', 'backing_file_depth': 'int',
             'encrypted': 'bool', 'encryption_key_missing': 'bool',
             'bps': 'int', 'bps_rd': 'int', 'bps_wr': 'int',
-            'iops': 'int', 'iops_rd': 'int', 'iops_wr': 'int'} }
+            'iops': 'int', 'iops_rd': 'int', 'iops_wr': 'int',
+            'image': 'ImageInfo' } }
 
 ##
 # @BlockDeviceIoStatus:

qmp-commands.hx

@@ -1704,6 +1704,47 @@ Each json-object contain the following:
          - "iops": limit total I/O operations per second (json-int)
          - "iops_rd": limit read operations per second (json-int)
          - "iops_wr": limit write operations per second (json-int)
+         - "image": the detail of the image, it is a json-object containing
+            the following:
+             - "filename": image file name (json-string)
+             - "format": image format (json-string)
+             - "virtual-size": image capacity in bytes (json-int)
+             - "dirty-flag": true if image is not cleanly closed, not present
+                             means clean (json-bool, optional)
+             - "actual-size": actual size on disk in bytes of the image, not
+                              present when image does not support thin
+                              provision (json-int, optional)
+             - "cluster-size": size of a cluster in bytes, not present if image
+                               format does not support it (json-int, optional)
+             - "encrypted": true if the image is encrypted, not present means
+                            false or the image format does not support
+                            encryption (json-bool, optional)
+             - "backing_file": backing file name, not present means no backing
+                               file is used or the image format does not
+                               support backing file chain
+                               (json-string, optional)
+             - "full-backing-filename": full path of the backing file, not
+                                        present if it equals backing_file or no
+                                        backing file is used
+                                        (json-string, optional)
+             - "backing-filename-format": the format of the backing file, not
+                                          present means unknown or no 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": 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 nanoseconds 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 nanoseconds to be used
+                                    with vm-clock-sec (json-int)
+             - "backing-image": the detail of the backing image, it is an
+                                optional json-object only present when a
+                                backing image present for this image
 
 - "io-status": I/O operation status, only present if the device supports it
                and the VM is configured to stop on errors. It's always reset
@@ -1724,14 +1765,38 @@ Example:
                "ro":false,
                "drv":"qcow2",
                "encrypted":false,
-               "file":"disks/test.img",
-               "backing_file_depth":0,
+               "file":"disks/test.qcow2",
+               "backing_file_depth":1,
                "bps":1000000,
                "bps_rd":0,
                "bps_wr":0,
                "iops":1000000,
                "iops_rd":0,
                "iops_wr":0,
+               "image":{
+                  "filename":"disks/test.qcow2",
+                  "format":"qcow2",
+                  "virtual-size":2048000,
+                  "backing_file":"base.qcow2",
+                  "full-backing-filename":"disks/base.qcow2",
+                  "backing-filename-format:"qcow2",
+                  "snapshots":[
+                     {
+                        "id": "1",
+                        "name": "snapshot1",
+                        "vm-state-size": 0,
+                        "date-sec": 10000200,
+                        "date-nsec": 12,
+                        "vm-clock-sec": 206,
+                        "vm-clock-nsec": 30
+                     }
+                  ],
+                  "backing-image":{
+                      "filename":"disks/base.qcow2",
+                      "format":"qcow2",
+                      "virtual-size":2048000
+                  }
+               }
             },
             "type":"unknown"
          },