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>

5 files changed, 46 insertions, 11 deletions

diff --git a/block.c b/block.c
index 40eb570..7f3e7bc 100644
--- a/block.c
+++ b/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);
-    }
 }
 
 /**
diff --git a/block/block-backend.c b/block/block-backend.c
index d97afa1..1a724a8 100644
--- a/block/block-backend.c
+++ b/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);
+
     }
 }
 
diff --git a/docs/qmp-commands.txt b/docs/qmp-commands.txt
index e0adceb..e044029 100644
--- a/docs/qmp-commands.txt
+++ b/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": {} }
diff --git a/docs/qmp-events.txt b/docs/qmp-events.txt
index 62a9f9c..e0a2365 100644
--- a/docs/qmp-events.txt
+++ b/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 } }
diff --git a/qapi/block.json b/qapi/block.json
index c896bd1..4661fc9 100644
--- a/qapi/block.json
+++ b/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