Re: [Qemu-block] [PATCH 06/22] qcow2: add dirty bitmaps extension

[Vladimir Sementsov-Ogievskiy]

On 12.10.2016 21:21, Max Reitz wrote:
> On 11.10.2016 14:09, Vladimir Sementsov-Ogievskiy wrote:
> > On 01.10.2016 17:46, Max Reitz wrote:
> > > On 30.09.2016 12:53, Vladimir Sementsov-Ogievskiy wrote:
> > > > Add dirty bitmap extension as specified in docs/specs/qcow2.txt.
> > > > For now, just mirror extension header into Qcow2 state and check
> > > > constraints.
> > > >
> > > > For now, disable image resize if it has bitmaps. It will be fixed later.
> > > >
> > > > Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
> > > > ---
> > > >    block/qcow2.c | 83
> > > > +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> > > >    block/qcow2.h |  4 +++
> > > >    2 files changed, 87 insertions(+)
> > > >
> > > > diff --git a/block/qcow2.c b/block/qcow2.c
> > > > index c079aa8..08c4ef9 100644
> > > > --- a/block/qcow2.c
> > > > +++ b/block/qcow2.c
> > > [...]
> > >
> > > > @@ -162,6 +164,62 @@ static int
> > > > qcow2_read_extensions(BlockDriverState *bs, uint64_t start_offset,
> > > >                }
> > > >                break;
> > > >    +        case QCOW2_EXT_MAGIC_DIRTY_BITMAPS:
> > > > +            ret = bdrv_pread(bs->file, offset, &bitmaps_ext, ext.len);
> > > Overflows with ext.len > sizeof(bitmaps_ext).
> > >
> > > (ext.len < sizeof(bitmaps_ext) is also wrong, but less dramatically so.)
> > >
> > > > +            if (ret < 0) {
> > > > +                error_setg_errno(errp, -ret, "ERROR: bitmaps_ext: "
> > > > +                                 "Could not read ext header");
> > > > +                return ret;
> > > > +            }
> > > > +
> > > > +            if (bitmaps_ext.reserved32 != 0) {
> > > > +                error_setg_errno(errp, -ret, "ERROR: bitmaps_ext: "
> > > > +                                 "Reserved field is not zero.");
> > > Please drop the full stop at the end.
> > what do you mean? goto to fail: here? or not stop at all, just print error?
> The "." at the end of the message. :-)
>
> (https://en.wikipedia.org/wiki/Full_stop)
>
> Max
aha, cool. didn't know this. )

--
Best regards,
Vladimir