Re: [Qemu-devel] [PATCH] qcow2: Get the request alignment for encrypted images from QCryptoBlock

["Daniel P. Berrangé" <berrange@redhat.com>]

On Mon, Oct 15, 2018 at 06:38:14PM +0200, Max Reitz wrote:
> On 11.10.18 12:58, Alberto Garcia wrote:
> > This doesn't have any practical effect at the moment because the
> > values of BDRV_SECTOR_SIZE, QCRYPTO_BLOCK_LUKS_SECTOR_SIZE and
> > QCRYPTO_BLOCK_QCOW_SECTOR_SIZE are all the same (512 bytes), but
> > future encryption methods could have different requirements.
> > 
> > Signed-off-by: Alberto Garcia <berto@igalia.com>
> > ---
> >  block/qcow2.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> This breaks non-LUKS encryption:
> 
> $ ./qemu-img create -f qcow2 -o encryption=on,encrypt.key-secret=secret
> --object secret,id=secret,data=foo foo.qcow2 64M
> Formatting 'foo.qcow2', fmt=qcow2 size=67108864 encryption=on
> encrypt.key-secret=secret cluster_size=65536 lazy_refcounts=off
> refcount_bits=16
> qemu-img: block.c:1248: bdrv_open_driver: Assertion
> `is_power_of_2(bs->bl.request_alignment)' failed.
> [1]    13589 abort (core dumped)  ./qemu-img create -f qcow2 -o
> encryption=on,encrypt.key-secret=secret --objec
> 
> (As seen in iotests 049, 087, 134, and 158.)

We failed to set sector size in the crypto backend when opening with
the NO_IO flag set. I just sent a fix for that. Feel free to queue it
as part of the block layer rather than waiting for my next crypto layer
pull request.

Regards,
Daniel
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