Re: [Qemu-devel] [PATCH 3/5] block: support compressed write for copy-on-read

[Anton Nefedov]

On 15/11/2017 9:49 PM, Max Reitz wrote:
> On 2017-11-14 11:16, Anton Nefedov wrote:
> > Signed-off-by: Anton Nefedov <address@hidden>
> > ---
> >   block/io.c         | 30 ++++++++++++++++++++++++------
> >   block/trace-events |  2 +-
> >   2 files changed, 25 insertions(+), 7 deletions(-)
> >
> > diff --git a/block/io.c b/block/io.c
> > index 3d5ef2c..93c6b24 100644
> > --- a/block/io.c
> > +++ b/block/io.c
>
> [...]
>
> > @@ -1209,6 +1220,13 @@ int coroutine_fn bdrv_co_preadv(BdrvChild *child,
> >           return ret;
> >       }
> >   
> > +    /* write compressed only makes sense with copy on read */
> > +    if ((flags & BDRV_REQ_WRITE_COMPRESSED) &&
> > +        !(flags & BDRV_REQ_COPY_ON_READ))
> > +    {
> > +        return -EINVAL;
> > +    }
> > +
>
> I think the assertion in bdrv_aligned_preadv() should be enough, but
> either way:
>
> Reviewed-by: Max Reitz <address@hidden>

Ok, and it will fail more loudly. Will remove.

> >       bdrv_inc_in_flight(bs);
> >   
> >       /* Don't do copy-on-read if we read data before write operation */