Re: [Qemu-devel] [PATCH v2 11/11] qmp: add command 'blockdev-backup'

[Wenchao Xia]

于 2013-7-18 12:41, Fam Zheng 写道:

On Wed, 07/17 06:44, Eric Blake wrote:

On 07/17/2013 03:42 AM, Fam Zheng wrote:

Similar to drive-backup, but this command uses a device id as target
instead of creating/opening an image file.

Signed-off-by: Fam Zheng <f...@redhat.com>
---
  blockdev.c       | 71 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
  qapi-schema.json | 49 ++++++++++++++++++++++++++++++++++++++
  qmp-commands.hx  | 22 ++++++++++++++++++
  3 files changed, 142 insertions(+)

+++ b/qapi-schema.json
@@ -1665,6 +1665,40 @@
              '*on-target-error': 'BlockdevOnError' } }

  ##
+# @BlockdevBackup
+#

+{ 'type': 'BlockdevBackup',
+  'data': { 'device': 'str', 'target': 'str',
+            'sync': 'MirrorSyncMode',
+            '*speed': 'int',
+            '*on-source-error': 'BlockdevOnError',
+            '*on-target-error': 'BlockdevOnError' } }

Seems okay.  But what is missing is the addition of this type into the
union used for 'transaction' - shouldn't it be possible to mix this with
other transaction capabilities?

Should be possible, as users may want point-in-time snapshot of multiple
disks. If this API looks OK, I will include it into transaction in the
next version.

  Instead of add this new API, how about extend Driver-backup API? This
patch is basically doing similar things with driver-backup, extension
of old API will save trouble to do same things driver-backup already
does, such as support qmp_transaction.

--
Best Regards

Wenchao Xia