[Qemu-devel] [PATCH v3 33/38] qmp: Introduce blockdev-change-medium

[Max Reitz <mreitz@redhat.com>]

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>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 blockdev.c                |  7 ++++---
 include/sysemu/blockdev.h |  2 --
 qapi-schema.json          |  6 ++++--
 qapi/block-core.json      | 23 +++++++++++++++++++++++
 qmp-commands.hx           | 31 +++++++++++++++++++++++++++++++
 qmp.c                     |  2 +-
 6 files changed, 63 insertions(+), 8 deletions(-)

diff --git a/blockdev.c b/blockdev.c
index 687b39f..a0de2d8 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -2066,8 +2066,9 @@ 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;
     BlockBackendRootState *blk_rs;
@@ -2090,7 +2091,7 @@ void qmp_change_blockdev(const char *device, const char *filename,
     bdrv_flags = blk_rs->read_only ? 0 : BDRV_O_RDWR;
     bdrv_flags |= blk_rs->open_flags & ~BDRV_O_RDWR;
 
-    if (format) {
+    if (has_format) {
         drv = bdrv_find_whitelisted_format(format, bdrv_flags & BDRV_O_RDWR);
         if (!drv) {
             error_setg(errp, "Invalid block format '%s'", format);
diff --git a/include/sysemu/blockdev.h b/include/sysemu/blockdev.h
index 7ca59b5..aa2865c 100644
--- a/include/sysemu/blockdev.h
+++ b/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);
 int hmp_drive_del(Monitor *mon, const QDict *qdict, QObject **ret_data);
 #endif
diff --git a/qapi-schema.json b/qapi-schema.json
index 0662a9b..7350d93 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -1787,8 +1787,10 @@
 #          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
 ##
diff --git a/qapi/block-core.json b/qapi/block-core.json
index cac67d9..7c4a44a 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -1909,6 +1909,29 @@
 
 
 ##
+# @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: 2.3
+##
+{ 'command': 'blockdev-change-medium',
+  'data': { 'device': 'str',
+            'filename': 'str',
+            '*format': 'str' } }
+
+
+##
 # @BlockErrorAction
 #
 # An enumeration of action that has been taken when a DISK I/O occurs
diff --git a/qmp-commands.hx b/qmp-commands.hx
index b910d46..46530c9 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -4085,6 +4085,37 @@ Example:
 EQMP
 
     {
+        .name       = "blockdev-change-medium",
+        .args_type  = "device:B,filename:F,format:s?",
+        .mhandler.cmd_new = qmp_marshal_input_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
+
+    {
         .name       = "query-memdev",
         .args_type  = "",
         .mhandler.cmd_new = qmp_marshal_input_query_memdev,
diff --git a/qmp.c b/qmp.c
index 99c14bf..bd28bed 100644
--- a/qmp.c
+++ b/qmp.c
@@ -428,7 +428,7 @@ 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);
     }
 }
 
-- 
2.4.1