block/qapi: Add qdev device name to query-block

With -blockdev/-device, users can indirectly create anonymous
BlockBackends, while the state of such backends is still of interest. As
a preparation for making such BBs visible in query-block, make sure that
they can be identified even without a name by adding the ID/QOM path of
their qdev device to BlockInfo.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>

block/qapi.c

@@ -322,11 +322,21 @@ static void bdrv_query_info(BlockBackend *blk, BlockInfo **p_info,
 {
     BlockInfo *info = g_malloc0(sizeof(*info));
     BlockDriverState *bs = blk_bs(blk);
+    char *qdev;
+
     info->device = g_strdup(blk_name(blk));
     info->type = g_strdup("unknown");
     info->locked = blk_dev_is_medium_locked(blk);
     info->removable = blk_dev_has_removable_media(blk);
 
+    qdev = blk_get_attached_dev_id(blk);
+    if (qdev && *qdev) {
+        info->has_qdev = true;
+        info->qdev = qdev;
+    } else {
+        g_free(qdev);
+    }
+
     if (blk_dev_has_tray(blk)) {
         info->has_tray_open = true;
         info->tray_open = blk_dev_is_tray_open(blk);

hmp.c

@@ -425,6 +425,9 @@ static void print_block_info(Monitor *mon, BlockInfo *info,
     }
 
     if (info) {
+        if (info->has_qdev) {
+            monitor_printf(mon, "    Attached to:      %s\n", info->qdev);
+        }
         if (info->has_io_status && info->io_status != BLOCK_DEVICE_IO_STATUS_OK) {
             monitor_printf(mon, "    I/O status:       %s\n",
                            BlockDeviceIoStatus_lookup[info->io_status]);

qapi/block-core.json

@@ -457,6 +457,9 @@
 #
 # @device: The device name associated with the virtual device.
 #
+# @qdev: The qdev ID, or if no ID is assigned, the QOM path of the block
+#        device. (since 2.10)
+#
 # @type: This field is returned only for compatibility reasons, it should
 #        not be used (always returns 'unknown')
 #
@@ -482,7 +485,7 @@
 # Since:  0.14.0
 ##
 { 'struct': 'BlockInfo',
-  'data': {'device': 'str', 'type': 'str', 'removable': 'bool',
+  'data': {'device': 'str', '*qdev': 'str', 'type': 'str', 'removable': 'bool',
            'locked': 'bool', '*inserted': 'BlockDeviceInfo',
            '*tray_open': 'bool', '*io-status': 'BlockDeviceIoStatus',
            '*dirty-bitmaps': ['BlockDirtyInfo'] } }
@@ -577,6 +580,7 @@
 #                   }
 #                }
 #             },
+#             "qdev": "ide_disk",
 #             "type":"unknown"
 #          },
 #          {
@@ -584,12 +588,15 @@
 #             "device":"ide1-cd0",
 #             "locked":false,
 #             "removable":true,
+#             "qdev": "/machine/unattached/device[23]",
+#             "tray_open": false,
 #             "type":"unknown"
 #          },
 #          {
 #             "device":"floppy0",
 #             "locked":false,
 #             "removable":true,
+#             "qdev": "/machine/unattached/device[20]",
 #             "type":"unknown"
 #          },
 #          {

tests/qemu-iotests/067.out

@@ -57,6 +57,7 @@ Testing: -drive file=TEST_DIR/t.qcow2,format=qcow2,if=none,id=disk -device virti
                 "file": "TEST_DIR/t.qcow2",
                 "encryption_key_missing": false
             },
+            "qdev": "/machine/peripheral/virtio0/virtio-backend",
             "type": "unknown"
         }
     ]