Re: [Qemu-devel] [PATCH resend] block: fix wrong order in live block migration setup

[Chai Wen <chaiw.fnst@cn.fujitsu.com>]

On 06/04/2014 05:23 PM, Stefan Hajnoczi wrote:

> On Wed, Jun 04, 2014 at 11:47:37AM +0800, chai wen wrote:
>>
>> The function init_blk_migration is better to be called before
>> set_dirty_tracking as the reasons below.
>>
>> If we want to track dirty blocks via dirty_maps on a BlockDriverState
>> when doing live block-migration, its correspoding 'BlkMigDevState' should be
>> added to block_mig_state.bmds_list first for subsequent processing.
>> Otherwise set_dirty_tracking will do nothing on an empty list than allocating
>> dirty_bitmaps for them. And bdrv_get_dirty_count will access the 
>> bmds->dirty_maps directly, then there would be a segfault triggered.
>>
>> If the set_dirty_tracking fails, qemu_savevm_state_cancel will handle
>> the cleanup of init_blk_migration automatically.
>>
>>
>> Reviewed-by: Fam Zheng <famz@redhat.com>
>> Signed-off-by: chai wen <chaiw.fnst@cn.fujitsu.com>
>> ---
>>  block-migration.c |    3 +--
>>  1 files changed, 1 insertions(+), 2 deletions(-)
> 
> Thanks, applied to my block tree:
> https://github.com/stefanha/qemu/commits/block
> 


OK， thanks for your attention about this fix. :)

thanks
chai wen

> Stefan
> .
> 



-- 
Regards

Chai Wen