Re: [Qemu-devel] [PATCH 0/2] deal with BDRV_BLOCK_RAW

[Vladimir Sementsov-Ogievskiy]

12.08.2019 22:50, Max Reitz wrote:
> On 12.08.19 21:46, Max Reitz wrote:
>> On 12.08.19 20:11, Vladimir Sementsov-Ogievskiy wrote:
>>> Hi all!
>>>
>>> I'm not sure, is it a bug or a feature, but using qcow2 under raw is
>>> broken. It should be either fixed like I propose (by Max's suggestion)
>>> or somehow forbidden (just forbid backing-file supporting node to be
>>> file child of raw-format node).
>>
>> I agree, I think only filters should return BDRV_BLOCK_RAW.
>>
>> (And not even them, they should just be handled transparently by
>> bdrv_co_block_status().  But that’s something for later.)
>>
>>> Vladimir Sementsov-Ogievskiy (2):
>>>    block/raw-format: switch to BDRV_BLOCK_DATA with BDRV_BLOCK_RECURSE
>>>    iotests: test mirroring qcow2 under raw format
>>>
>>>   block/raw-format.c         |  2 +-
>>>   tests/qemu-iotests/263     | 46 ++++++++++++++++++++++++++++++++++++++
>>>   tests/qemu-iotests/263.out | 12 ++++++++++
>>>   tests/qemu-iotests/group   |  1 +
>>>   4 files changed, 60 insertions(+), 1 deletion(-)
>>>   create mode 100755 tests/qemu-iotests/263
>>>   create mode 100644 tests/qemu-iotests/263.out
>>
>> Thanks, applied to my block-next branch:
>>
>> https://git.xanclic.moe/XanClic/qemu/commits/branch/block-next
> 
> Oops, maybe not.  221 needs to be adjusted.
> 


Hmm yes, I forget to run tests.. Areas which were zero becomes data|zero, it
don't look good.

So, it's not quite right to report DATA | RECURSE, we actually should report
DATA_OR_ZERO | RECURSE, which is actually ALLOCATED | RECURSE, as otherwise
DATA will be set in final result (generic layer must not drop it, obviously).

ALLOCATED never returned by drivers but seems it should be. I'll think a bit and
resend something new.


-- 
Best regards,
Vladimir