From 8e79bb0e25c48354f895077b206ded171507ba55 Mon Sep 17 00:00:00 2001

From: Jeffrey Cody <jcody@redhat.com>

Date: Fri, 19 Sep 2014 03:18:59 +0200

Subject: [PATCH 20/20] block: add __com.redhat_change-backing-file qmp command

Message-id: <c7fc7cefc7588dca2d02b0cc0051cdbdadbf20ac.1411096194.git.jcody@redhat.com>

Patchwork-id: 61313

O-Subject: [PATCH qemu-kvm-rhev RHEL7.0.z 4/4] block: add __com.redhat_change-backing-file qmp command

Bugzilla: 1122925

RH-Acked-by: Kevin Wolf <kwolf@redhat.com>

RH-Acked-by: Eric Blake <eblake@redhat.com>

RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>

Upstream, the QAPI command 'change-backing-file' was added in a patch,

as part of a series that allowed libvirt to specify backing file

names in block-commit and block-stream.

This standalone QAPI (change-backing-file) is not currently in use by

libvirt, except as a witness that QEMU has the ability to change backing

files in block-commit and block-stream.

However, change-backing-file also relies on node-names functionality,

which is not present in RHEL7.0.  The backport of node-names would also

be fairly instrusive, especially for a command that is not going to be

used beyond verifying its presence.

This downstream patch adds __com.redhat_change-backing-file, which

accepts the same arguments as its upstream namesake.  However, no action

is performed, and the command always returns QERR_UNSUPPORTED.

This is not placed inside the RHEL/RHEV differentiation commands, as it

is not a live block operation (upstream or the dummy version), and

returns synchronously.

Signed-off-by: Jeff Cody <jcody@redhat.com>

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>

---

 blockdev.c       |    8 ++++++++

 qapi-schema.json |   16 ++++++++++++++++

 qmp-commands.hx  |   22 ++++++++++++++++++++++

 3 files changed, 46 insertions(+), 0 deletions(-)

diff --git a/blockdev.c b/blockdev.c

index 09ef3f7..7d4a53f 100644

--- a/blockdev.c

+++ b/blockdev.c

@@ -1782,6 +1782,14 @@ void qmp_block_job_complete(const char *device, Error **errp)

     block_job_complete(job, errp);

 }

+void qmp___com_redhat_change_backing_file(const char *device,

+                                          const char *image_node_name,

+                                          const char *backing_file,

+                                          Error **errp)

+{

+    error_set(errp, QERR_UNSUPPORTED);

+}

+

 void qmp_blockdev_add(BlockdevOptions *options, Error **errp)

 {

     QmpOutputVisitor *ov = qmp_output_visitor_new();

diff --git a/qapi-schema.json b/qapi-schema.json

index 40bd2a6..d3d4e57 100644

--- a/qapi-schema.json

+++ b/qapi-schema.json

@@ -1832,6 +1832,22 @@

   'data': {'command-line': 'str', '*cpu-index': 'int'},

   'returns': 'str' }

+##

+# @__com.redhat_change-backing-file

+#

+# This is a placeholder function, that exists as a witness for libvirt

+# that the ability to specify backing files in block-commit and block-stream

+# exists in this version of QEMU.

+#

+# It has the same argument requirements as the upstream 'change-backing-file',

+# but performs no action.

+#

+# Returns: NotSupported

+##

+{ 'command': '__com.redhat_change-backing-file',

+  'data': { 'device': 'str', 'image-node-name': 'str',

+            'backing-file': 'str' } }

+

 #_rhev-only CONFIG_LIVE_BLOCK_OPS

 ##

 # @block-commit

diff --git a/qmp-commands.hx b/qmp-commands.hx

index c07cf8a..e164ff8 100644

--- a/qmp-commands.hx

+++ b/qmp-commands.hx

@@ -1241,6 +1241,28 @@ EQMP

 #endif

     {

+        .name       = RFQDN_REDHAT "change-backing-file",

+        .args_type  = "device:s,image-node-name:s,backing-file:s",

+        .mhandler.cmd_new = qmp_marshal_input___com_redhat_change_backing_file,

+    },

+

+SQMP

+@__com.redhat_change-backing-file

+-------------------

+@__com.redhat_change-backing-file

+

+This is a placeholder function, that exists as a witness for libvirt

+that the ability to specify backing files block-commit and block-stream

+exists in this version of QEMU.

+

+It has the same argument requirements as the upstream 'change-backing-file',

+but performs no action.

+

+Returns: NotSupported

+

+EQMP

+

+    {

         .name       = "balloon",

         .args_type  = "value:M",

         .mhandler.cmd_new = qmp_marshal_input_balloon,

-- 

1.7.1