Re: [Qemu-devel] [PATCH v2.5 00/10] block: incremental backup transactions

[Kashyap Chamarthy <kchamart@redhat.com>]

On Fri, Apr 17, 2015 at 09:01:10PM -0400, John Snow wrote:
> I am not prepared to send a v3 on this, primarily because I am still
> waffling on whether or not to do the code motion patch that is present in
> patch #8 of v2 of this series.
> 
> However, for the purposes of testing, reviewers may find it convenient to
> have a new version of this series that applies cleanly in concert with v6 of
> the transactionless series, so I am presenting an informal "version 2.5" of
> this series.
> 
> Patches are available on github:
> https://github.com/jnsnow/qemu/commits/incremental-transactions

I just tested this w/o creating the target image, and I don't see any
error thrown.

Details:

I tested with this branch:

    https://github.com/jnsnow/qemu/commits/incremental-transactions

    $ git checkout -b v2.5-and-v6-inc-backup jsnow/incremental-transactions
    $ git describe
    v2.3.0-rc3-37-g6932a32


With a QEMU invocation (of a CirrOS disk image) with QMP server:
    . . .
    char device redirected to /dev/pts/31 (label charserial0)
    QEMU waiting for connection on: disconnected:tcp:localhost:4444,server


And, invoking `drive-backup` *without* pre-creating the target image
(i.e. 'incremental.o.img'):

    { 'execute': 'drive-backup',
      'arguments': {
        'device': 'ide0-0-0',
        'bitmap': 'bitmap0',
        'sync': 'dirty-bitmap',
        'target': 'incremental.0.img',
        'mode': 'existing',
        'format': 'qcow2'
      }
    }

Results in:

    {"QMP": {"version": {"qemu": {"micro": 93, "minor": 2, "major": 2},
    "package": ""}, "capabilities": []}} {"return": {}}

Instead of an "error". Is this a bug?

On a related note, Kevin Wolf said on IRC that he gets an error (without
'bitmap') when tested from QEMU master branch.


-- 
/kashyap