block: Add qdev ID to DEVICE_TRAY_MOVED

The event currently only contains the BlockBackend name. However, with
anonymous BlockBackends, this is always the empty string. Add the qdev
ID (or if none was given, the QOM path) so that the user can still see
which device caused the event.

Event generation has to be moved from bdrv_eject() to the BlockBackend
because the BDS doesn't know the attached device, but that's easy
because blk_eject() is the only user of it.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>

block.c

@@ -3360,17 +3360,10 @@ int bdrv_media_changed(BlockDriverState *bs)
 void bdrv_eject(BlockDriverState *bs, bool eject_flag)
 {
     BlockDriver *drv = bs->drv;
-    const char *device_name;
 
     if (drv && drv->bdrv_eject) {
         drv->bdrv_eject(bs, eject_flag);
     }
-
-    device_name = bdrv_get_device_name(bs);
-    if (device_name[0] != '\0') {
-        qapi_event_send_device_tray_moved(device_name,
-                                          eject_flag, &error_abort);
-    }
 }
 
 /**

block/block-backend.c

@@ -565,6 +565,23 @@ void *blk_get_attached_dev(BlockBackend *blk)
     return blk->dev;
 }
 
+/* Return the qdev ID, or if no ID is assigned the QOM path, of the block
+ * device attached to the BlockBackend. */
+static char *blk_get_attached_dev_id(BlockBackend *blk)
+{
+    DeviceState *dev;
+
+    assert(!blk->legacy_dev);
+    dev = blk->dev;
+
+    if (!dev) {
+        return g_strdup("");
+    } else if (dev->id) {
+        return g_strdup(dev->id);
+    }
+    return object_get_canonical_path(OBJECT(dev));
+}
+
 /*
  * Return the BlockBackend which has the device model @dev attached if it
  * exists, else null.
@@ -612,13 +629,17 @@ void blk_dev_change_media_cb(BlockBackend *blk, bool load)
     if (blk->dev_ops && blk->dev_ops->change_media_cb) {
         bool tray_was_open, tray_is_open;
 
+        assert(!blk->legacy_dev);
+
         tray_was_open = blk_dev_is_tray_open(blk);
         blk->dev_ops->change_media_cb(blk->dev_opaque, load);
         tray_is_open = blk_dev_is_tray_open(blk);
 
         if (tray_was_open != tray_is_open) {
-            qapi_event_send_device_tray_moved(blk_name(blk), tray_is_open,
+            char *id = blk_get_attached_dev_id(blk);
+            qapi_event_send_device_tray_moved(blk_name(blk), id, tray_is_open,
                                               &error_abort);
+            g_free(id);
         }
     }
 }
@@ -1316,9 +1337,19 @@ void blk_lock_medium(BlockBackend *blk, bool locked)
 void blk_eject(BlockBackend *blk, bool eject_flag)
 {
     BlockDriverState *bs = blk_bs(blk);
+    char *id;
+
+    /* blk_eject is only called by qdevified devices */
+    assert(!blk->legacy_dev);
 
     if (bs) {
         bdrv_eject(bs, eject_flag);
+
+        id = blk_get_attached_dev_id(blk);
+        qapi_event_send_device_tray_moved(blk_name(blk), id,
+                                          eject_flag, &error_abort);
+        g_free(id);
+
     }
 }
 

docs/qmp-commands.txt

@@ -3239,6 +3239,7 @@ Example:
                     "microseconds": 716996 },
      "event": "DEVICE_TRAY_MOVED",
      "data": { "device": "ide1-cd0",
+               "id": "ide0-1-0",
                "tray-open": true } }
 
 <- { "return": {} }
@@ -3267,6 +3268,7 @@ Example:
                     "microseconds": 272147 },
      "event": "DEVICE_TRAY_MOVED",
      "data": { "device": "ide1-cd0",
+               "id": "ide0-1-0",
                "tray-open": false } }
 
 <- { "return": {} }
@@ -3303,6 +3305,7 @@ Example:
                     "microseconds": 549958 },
      "event": "DEVICE_TRAY_MOVED",
      "data": { "device": "ide1-cd0",
+               "id": "ide0-1-0",
                "tray-open": true } }
 
 <- { "return": {} }

docs/qmp-events.txt

@@ -220,12 +220,16 @@ or by HMP/QMP commands.
 
 Data:
 
-- "device": device name (json-string)
+- "device": Block device name. This is always present for compatibility
+            reasons, but it can be empty ("") if the image does not have a
+            device name associated. (json-string)
+- "id": The name or QOM path of the guest device (json-string)
 - "tray-open": true if the tray has been opened or false if it has been closed
                (json-bool)
 
 { "event": "DEVICE_TRAY_MOVED",
   "data": { "device": "ide1-cd0",
+            "id": "/machine/unattached/device[22]",
             "tray-open": true
   },
   "timestamp": { "seconds": 1265044230, "microseconds": 450486 } }

qapi/block.json

@@ -195,14 +195,18 @@
 # Emitted whenever the tray of a removable device is moved by the guest or by
 # HMP/QMP commands
 #
-# @device: device name
+# @device: Block device name. This is always present for compatibility
+#          reasons, but it can be empty ("") if the image does not
+#          have a device name associated.
+#
+# @id: The name or QOM path of the guest device
 #
 # @tray-open: true if the tray has been opened or false if it has been closed
 #
 # Since: 1.1
 ##
 { 'event': 'DEVICE_TRAY_MOVED',
-  'data': { 'device': 'str', 'tray-open': 'bool' } }
+  'data': { 'device': 'str', 'id': 'str', 'tray-open': 'bool' } }
 
 ##
 # @QuorumOpType