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

[Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>]

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 <vsementsov@virtuozzo.com>
>>>> ---
>>>>    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