Re: [PATCH for-4.2 0/2] Fix bitmap migration

[Vladimir Sementsov-Ogievskiy]

25.11.2019 16:50, Max Reitz wrote:
> On 25.11.19 13:52, Vladimir Sementsov-Ogievskiy wrote:
>> Hi all!
>>
>> We've faced a bug in rhev-2.12.0-33.el7-based Qemu.
>> In upstream, bug introduced in 4.0 by 74da6b943565c45
>> "block/dirty-bitmaps: implement inconsistent bit" commit.
>> At this commit we started to load inconsistent bitmap instead of
>> silently ignoring them, and it now I see that it breaks migration.
>>
>> The fix is very simple, so I think it's OK for 4.2.. Still, it's not a
>> degradation, so we may postpone it to 5.0.
>>
>> Vladimir Sementsov-Ogievskiy (2):
>>    block/qcow2-bitmap: fix bitmap migration
>>    iotests: add new test cases to bitmap migration
>>
>>   block/qcow2-bitmap.c       | 21 ++++++++++++++++++++-
>>   tests/qemu-iotests/169     | 22 +++++++++++++++-------
>>   tests/qemu-iotests/169.out |  4 ++--
>>   3 files changed, 37 insertions(+), 10 deletions(-)
> 
> Reviewed-by: Max Reitz <address@hidden>
> 
> Makes sense to me to put this into 4.2, but I don’t think it would
> survive Peter’s check list. :?

It depends on how much the fixed case is popular..

Actually, anyone who tries to migrate bitmaps with dirty-bitmaps capability
enabled and with shared storage will very possibly run into this bug.

But who is it, except for Virtuozzo, I don't know:) Still, I see that a lot
of that staff merged into Rhel Qemu we based on, so at least this should go
to qemu-stable and to Rhel update.

> 
> (https://lists.nongnu.org/archive/html/qemu-block/2019-11/msg00807.html)
> 
> Max
> 


-- 
Best regards,
Vladimir