Re: [Qemu-block] [PATCH v6] migration/block: use blk_pwrite_zeroes for each zero cluster

[858585 jemmy]

On Thu, Apr 13, 2017 at 10:16 PM, Stefan Hajnoczi <address@hidden> wrote:
> On Thu, Apr 13, 2017 at 10:34:28AM +0800, address@hidden wrote:
>> From: Lidong Chen <address@hidden>
>>
>> BLOCK_SIZE is (1 << 20), qcow2 cluster size is 65536 by default,
>> this may cause the qcow2 file size to be bigger after migration.
>> This patch checks each cluster, using blk_pwrite_zeroes for each
>> zero cluster.
>>
>> Reviewed-by: Stefan Hajnoczi <address@hidden>
>> Signed-off-by: Lidong Chen <address@hidden>
>> ---
>> v6 changelog:
>> Fix up some grammar in the comment.
>> ---
>>  migration/block.c | 35 +++++++++++++++++++++++++++++++++--
>>  1 file changed, 33 insertions(+), 2 deletions(-)
>
> I fixed the following gcc warning when merging the patch:
>
>   migration/block.c:958:25: error: ‘cluster_size’ may be used uninitialized 
> in this function [-Werror=maybe-uninitialized]
>                             buffer_is_zero(cur_buf, cluster_size)) {

Thanks，i will check gcc warning next time.

>
> Thanks, applied to my block-next tree:
> https://github.com/stefanha/qemu/commits/block-next
>
> Stefan