Re: [PATCH] qapi: Craft the BlockdevCreateOptionsLUKS comment

[Kevin Wolf <kwolf@redhat.com>]

Am 28.02.2024 um 12:30 hat Daniel P. Berrangé geschrieben:
> On Wed, Feb 28, 2024 at 11:17:37AM +0100, Kevin Wolf wrote:
> > Until now, @size has been mandatory for creating images with every
> > driver. Maybe we should even have put it into BlockdevCreateOptions's
> > base, because without a size, you're not really creating an image.
> 
> NB, @size isn't mandatory for creating images. It isn't required
> when creating qcow2 files with backing stores, as the size is
> acquired from the backing file instead.
> 
> $ qemu-img create demo.raw 1g
> Formatting 'demo.raw', fmt=raw size=1073741824
> $ qemu-img create -o backing_file=demo.raw -o backing_fmt=raw -f qcow2 demo.qcow2
> Formatting 'demo.qcow2', fmt=qcow2 cluster_size=65536 extended_l2=off compression_type=zlib size=1073741824 backing_file=demo.raw backing_fmt=raw lazy_refcounts=off refcount_bits=16

Yes, 'qemu-img create' is different, it adds some convenience magic like
this. But for 'blockdev-create', it's mandatory for every driver. I
double checked the QAPI schema.

Kevin