qmp: Introduce blockdev-change-medium

Introduce a new QMP command 'blockdev-change-medium' which is intended
to replace the 'change' command for block devices. The existing function
qmp_change_blockdev() is accordingly renamed to
qmp_blockdev_change_medium().

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

blockdev.c

@@ -2143,8 +2143,9 @@ void qmp_blockdev_insert_medium(const char *device, const char *node_name,
     qmp_blockdev_insert_anon_medium(device, bs, errp);
 }
 
-void qmp_change_blockdev(const char *device, const char *filename,
-                         const char *format, Error **errp)
+void qmp_blockdev_change_medium(const char *device, const char *filename,
+                                bool has_format, const char *format,
+                                Error **errp)
 {
     BlockBackend *blk;
     BlockDriverState *medium_bs = NULL;
@@ -2165,7 +2166,7 @@ void qmp_change_blockdev(const char *device, const char *filename,
 
     bdrv_flags = blk_get_open_flags_from_root_state(blk);
 
-    if (format) {
+    if (has_format) {
         options = qdict_new();
         qdict_put(options, "driver", qstring_from_str(format));
     }

include/sysemu/blockdev.h

@@ -63,8 +63,6 @@ DriveInfo *drive_new(QemuOpts *arg, BlockInterfaceType block_default_type);
 
 /* device-hotplug */
 
-void qmp_change_blockdev(const char *device, const char *filename,
-                         const char *format, Error **errp);
 void hmp_commit(Monitor *mon, const QDict *qdict);
 void hmp_drive_del(Monitor *mon, const QDict *qdict);
 #endif

qapi-schema.json

@@ -1856,8 +1856,10 @@
 #          device's password.  The behavior of reads and writes to the block
 #          device between when these calls are executed is undefined.
 #
-# Notes:  It is strongly recommended that this interface is not used especially
-#         for changing block devices.
+# Notes:  This interface is deprecated, and it is strongly recommended that you
+#         avoid using it.  For changing block devices, use
+#         blockdev-change-medium; for changing VNC parameters, use
+#         change-vnc-password.
 #
 # Since: 0.14.0
 ##

qapi/block-core.json

@@ -1958,6 +1958,29 @@
             'node-name': 'str'} }
 
 
+##
+# @blockdev-change-medium:
+#
+# Changes the medium inserted into a block device by ejecting the current medium
+# and loading a new image file which is inserted as the new medium (this command
+# combines blockdev-open-tray, blockdev-remove-medium, blockdev-insert-medium
+# and blockdev-close-tray).
+#
+# @device:          block device name
+#
+# @filename:        filename of the new image to be loaded
+#
+# @format:          #optional, format to open the new image with (defaults to
+#                   the probed format)
+#
+# Since: 2.5
+##
+{ 'command': 'blockdev-change-medium',
+  'data': { 'device': 'str',
+            'filename': 'str',
+            '*format': 'str' } }
+
+
 ##
 # @BlockErrorAction
 #

qmp-commands.hx

@@ -4179,6 +4179,37 @@ Example:
                       }
                    } } ] }
 
+EQMP
+
+    {
+        .name       = "blockdev-change-medium",
+        .args_type  = "device:B,filename:F,format:s?",
+        .mhandler.cmd_new = qmp_marshal_blockdev_change_medium,
+    },
+
+SQMP
+blockdev-change-medium
+----------------------
+
+Changes the medium inserted into a block device by ejecting the current medium
+and loading a new image file which is inserted as the new medium.
+
+Arguments:
+
+- "device": device name (json-string)
+- "filename": filename of the new image (json-string)
+- "format": format of the new image (json-string, optional)
+
+Examples:
+
+1. Change a removable medium
+
+-> { "execute": "blockdev-change-medium",
+             "arguments": { "device": "ide1-cd0",
+                            "filename": "/srv/images/Fedora-12-x86_64-DVD.iso",
+                            "format": "raw" } }
+<- { "return": {} }
+
 EQMP
 
     {

qmp.c

@@ -414,7 +414,7 @@ void qmp_change(const char *device, const char *target,
     if (strcmp(device, "vnc") == 0) {
         qmp_change_vnc(target, has_arg, arg, errp);
     } else {
-        qmp_change_blockdev(device, target, arg, errp);
+        qmp_blockdev_change_medium(device, target, has_arg, arg, errp);
     }
 }
 

ui/cocoa.m

@@ -1113,10 +1113,12 @@ - (void)changeDeviceMedia:(id)sender
         }
 
         Error *err = NULL;
-        qmp_change_blockdev([drive cStringUsingEncoding: NSASCIIStringEncoding],
-                            [file cStringUsingEncoding: NSASCIIStringEncoding],
-                            "raw",
-                            &err);
+        qmp_blockdev_change_medium([drive cStringUsingEncoding:
+                                          NSASCIIStringEncoding],
+                                   [file cStringUsingEncoding:
+                                         NSASCIIStringEncoding],
+                                   true, "raw",
+                                   &err);
         handleAnyDeviceErrors(err);
     }
 }