Re: [Qemu-devel] [PATCH] luks: Allow share-rw=on

[Kevin Wolf <kwolf@redhat.com>]

Am 14.08.2018 um 09:27 hat Daniel P. Berrangé geschrieben:
> On Tue, Aug 14, 2018 at 03:25:51PM +0800, Fam Zheng wrote:
> > Format drivers such as qcow2 don't allow sharing the same image between
> > two QEMU instances in order to prevent image corruptions, because of
> > metadata cache. LUKS driver don't modify metadata except for when
> > creating image, so it is safe to relax the permission. This makes
> > share-rw=on property work on virtual devices.
> > 
> > Suggested-by: Daniel P. Berrangé <berrange@redhat.com>
> > Signed-off-by: Fam Zheng <famz@redhat.com>
> > ---
> >  block/crypto.c | 4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> > 
> > diff --git a/block/crypto.c b/block/crypto.c
> > index 146d81c90a..33ee01bebd 100644
> > --- a/block/crypto.c
> > +++ b/block/crypto.c
> > @@ -627,7 +627,9 @@ BlockDriver bdrv_crypto_luks = {
> >      .bdrv_probe         = block_crypto_probe_luks,
> >      .bdrv_open          = block_crypto_open_luks,
> >      .bdrv_close         = block_crypto_close,
> > -    .bdrv_child_perm    = bdrv_format_default_perms,
> > +    /* This driver doesn't modify LUKS metadata except when creating image.
> > +     * Allow share-rw=on as a special case. */
> > +    .bdrv_child_perm    = bdrv_filter_default_perms,
> >      .bdrv_co_create     = block_crypto_co_create_luks,
> >      .bdrv_co_create_opts = block_crypto_co_create_opts_luks,
> >      .bdrv_co_truncate   = block_crypto_co_truncate,
> 
> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>

Thanks, applied to the block branch.

Kevin