Re: [Qemu-block] [Qemu-devel] [PATCH 3/7] qcow: Support .bdrv_co_create

[Daniel P . Berrangé]

On Wed, Mar 14, 2018 at 06:16:18AM -0500, Eric Blake wrote:
> On 03/09/2018 03:46 PM, Kevin Wolf wrote:
> > This adds the .bdrv_co_create driver callback to qcow, which
> > enables image creation over QMP.
> > 
> > Signed-off-by: Kevin Wolf <address@hidden>
> > ---
> >   qapi/block-core.json |  21 +++++-
> >   block/qcow.c         | 196 
> > ++++++++++++++++++++++++++++++++++-----------------
> >   2 files changed, 150 insertions(+), 67 deletions(-)
> 
> >   ##
> > +# @BlockdevCreateOptionsQcow:
> > +#
> > +# Driver specific image creation options for qcow.
> > +#
> > +# @file             Node to create the image format on
> > +# @size             Size of the virtual disk in bytes
> > +# @backing-file     File name of the backing file if a backing file
> > +#                   should be used
> > +# @encrypt          Encryption options if the image should be encrypted
> 
> Idea for followup patch - we should strongly document that encryption of
> qcow is discouraged as insecure, and/or mention that qcow2 is generally a
> better option than qcow when creating images over QMP.

Yes to the encryption note, but we should definitely document that
'qcow' is deprecated in general - there's little good reason you would
want to use it - it has terrible performance when allocating new clusters.


Regards,
Daniel
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