block: Add 'x-blockdev-del' QMP command

This command is still experimental, hence the name.

This is the companion to 'blockdev-add'. It allows deleting a
BlockBackend with its associated BlockDriverState tree, or a
BlockDriverState that is not attached to any backend.

In either case, the command fails if the reference count is greater
than 1 or the BlockDriverState has any parents.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 6cfc148c77aca1da942b094d811bfa3fcf7ac7bb.1446475331.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>

1 files changed, 59 insertions, 2 deletions

diff --git a/qmp-commands.hx b/qmp-commands.hx
index 5fd6f9c0e3..02c0c5bc42 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -3946,8 +3946,8 @@ blockdev-add
 Add a block device.
 
 This command is still a work in progress.  It doesn't support all
-block drivers, it lacks a matching blockdev-del, and more.  Stay away
-from it unless you want to help with its development.
+block drivers among other things.  Stay away from it unless you want
+to help with its development.
 
 Arguments:
 
@@ -3993,6 +3993,63 @@ Example (2):
 EQMP
 
     {
+        .name       = "x-blockdev-del",
+        .args_type  = "id:s?,node-name:s?",
+        .mhandler.cmd_new = qmp_marshal_x_blockdev_del,
+    },
+
+SQMP
+x-blockdev-del
+------------
+Since 2.5
+
+Deletes a block device thas has been added using blockdev-add.
+The selected device can be either a block backend or a graph node.
+
+In the former case the backend will be destroyed, along with its
+inserted medium if there's any. The command will fail if the backend
+or its medium are in use.
+
+In the latter case the node will be destroyed. The command will fail
+if the node is attached to a block backend or is otherwise being
+used.
+
+One of "id" or "node-name" must be specified, but not both.
+
+This command is still a work in progress and is considered
+experimental. Stay away from it unless you want to help with its
+development.
+
+Arguments:
+
+- "id": Name of the block backend device to delete (json-string, optional)
+- "node-name": Name of the graph node to delete (json-string, optional)
+
+Example:
+
+-> { "execute": "blockdev-add",
+     "arguments": {
+         "options": {
+             "driver": "qcow2",
+             "id": "drive0",
+             "file": {
+                 "driver": "file",
+                 "filename": "test.qcow2"
+             }
+         }
+     }
+   }
+
+<- { "return": {} }
+
+-> { "execute": "x-blockdev-del",
+     "arguments": { "id": "drive0" }
+   }
+<- { "return": {} }
+
+EQMP
+
+    {
         .name       = "blockdev-open-tray",
         .args_type  = "device:s,force:b?",
         .mhandler.cmd_new = qmp_marshal_blockdev_open_tray,