Re: [PATCH v2 4/4] qcow2: Use BDRV_SECTOR_SIZE instead of the hardcoded value

[Alberto Garcia]

On Tue 14 Jan 2020 03:15:48 PM CET, Max Reitz <mre...@redhat.com> wrote:
>> @@ -3836,7 +3837,7 @@ qcow2_co_copy_range_from(BlockDriverState *bs,
>>          case QCOW2_CLUSTER_NORMAL:
>>              child = s->data_file;
>>              copy_offset += offset_into_cluster(s, src_offset);
>> -            if ((copy_offset & 511) != 0) {
>> +            if (!QEMU_IS_ALIGNED(copy_offset, BDRV_SECTOR_SIZE)) {
>
> Hm.  I don’t get this one.

Ok, this came with Fam's "qemu-img convert with copy offloading" series:

   https://lists.gnu.org/archive/html/qemu-block/2018-06/msg00015.html

and qemu-img uses sectors here:

   blk_co_copy_range(..., sector_num << BDRV_SECTOR_BITS,
                     n << BDRV_SECTOR_BITS, ...)

so I guess that's why the check is there. Again, I think this should be
bl.request_alignment, because as far as I can tell copy_file_range()
works just fine unless O_DIRECT is used.

Berto