Re: [Qemu-devel] [PATCH v2 4/4] block: convert qcrypto_block_encrypt|decrypt to take bytes offset

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

On Thu, Aug 31, 2017 at 10:17:43AM -0500, Eric Blake wrote:
> On 08/31/2017 06:05 AM, Daniel P. Berrange wrote:
> > Instead of sector offset, take the bytes offset when encrypting
> > or decrypting data.
> > 
> > Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
> > ---
> >  block/crypto.c         |  8 ++++----
> >  block/qcow.c           |  7 +++++--
> >  block/qcow2-cluster.c  |  8 +++-----
> >  block/qcow2.c          |  4 ++--
> >  crypto/block-luks.c    | 12 ++++++++----
> >  crypto/block-qcow.c    | 12 ++++++++----
> >  crypto/block.c         | 14 ++++++++------
> >  crypto/blockpriv.h     |  4 ++--
> >  include/crypto/block.h | 14 ++++++++------
> >  9 files changed, 48 insertions(+), 35 deletions(-)
> > 
> > diff --git a/block/crypto.c b/block/crypto.c
> > index 40daa77188..6b8d88efbc 100644
> > --- a/block/crypto.c
> > +++ b/block/crypto.c
> > @@ -426,8 +426,8 @@ block_crypto_co_preadv(BlockDriverState *bs, uint64_t offset, uint64_t bytes,
> >              goto cleanup;
> >          }
> >  
> > -        if (qcrypto_block_decrypt(crypto->block, sector_num, cipher_data,
> > -                                  cur_bytes, NULL) < 0) {
> > +        if (qcrypto_block_decrypt(crypto->block, offset + bytes_done,
> > +                                  cipher_data, cur_bytes, NULL) < 0) {
> 
> How close are we to getting rid of even needing 'sector_num' as a variable?

I thought there was more usage, but I just realized we can in fact
remove it in this patch.

> 
> > +++ b/block/qcow.c
> > @@ -456,7 +456,9 @@ static uint64_t get_cluster_offset(BlockDriverState *bs,
> >                          if (i < n_start || i >= n_end) {
> >                              Error *err = NULL;
> >                              memset(s->cluster_data, 0x00, 512);
> > -                            if (qcrypto_block_encrypt(s->crypto, start_sect + i,
> > +                            if (qcrypto_block_encrypt(s->crypto,
> > +                                                      start_sect + i *
> > +                                                      BDRV_SECTOR_SIZE,
> 
> Umm, not the same.  You want (start_sect + i) * BDRV_SECTOR_SIZE.

Heh, oppps.


Regards,
Daniel
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