Re: [Qemu-devel] [PATCH 2/3] block/backup: disable copy_range for compressed backup

[Vladimir Sementsov-Ogievskiy]

30.07.2019 21:22, John Snow wrote:
> 
> 
> On 7/30/19 12:32 PM, Vladimir Sementsov-Ogievskiy wrote:
>> Enabled by default copy_range ignores compress option. It's definitely
>> unexpected for user.
>>
>> It's broken since introduction of copy_range usage in backup in
>> 9ded4a011496.
>>
>> Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
>> ---
>>   block/backup.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/block/backup.c b/block/backup.c
>> index f4aaf08df3..c5f941101a 100644
>> --- a/block/backup.c
>> +++ b/block/backup.c
>> @@ -645,7 +645,7 @@ BlockJob *backup_job_create(const char *job_id, 
>> BlockDriverState *bs,
>>       job->cluster_size = cluster_size;
>>       job->copy_bitmap = copy_bitmap;
>>       copy_bitmap = NULL;
>> -    job->use_copy_range = true;
>> +    job->use_copy_range = !compress; /* compression isn't supported for it 
>> */
>>       job->copy_range_size = 
>> MIN_NON_ZERO(blk_get_max_transfer(job->common.blk),
>>                                           blk_get_max_transfer(job->target));
>>       job->copy_range_size = MAX(job->cluster_size,
>>
> 
> Agree, these aren't compatible options. Is this worth a note in
> docs/interop/live-block-operations.rst?

Use_copy_range is not an user-visible option and it's not documented as I can 
see,
so I think we don't need.

> 
> Reviewed-by: John Snow <address@hidden>
> 


-- 
Best regards,
Vladimir