Re: [Qemu-devel] [PATCH 6/8] qemu-img: use bdrv_write_zeroes to write zeroes

[Peter Lieven]

Am 24.06.2013 16:33, schrieb Paolo Bonzini:
> Il 22/06/2013 22:58, Peter Lieven ha scritto:
>> Signed-off-by: Peter Lieven <address@hidden>
>> ---
>>  qemu-img.c |   10 +++++++---
>>  1 file changed, 7 insertions(+), 3 deletions(-)
>>
>> diff --git a/qemu-img.c b/qemu-img.c
>> index 809b4f1..5aa53ab 100644
>> --- a/qemu-img.c
>> +++ b/qemu-img.c
>> @@ -1513,9 +1513,13 @@ static int img_convert(int argc, char **argv)
>>                     If the output is to a host device, we also write out
>>                     sectors that are entirely 0, since whatever data was
>>                     already there is garbage, not 0s. */
>> -                if (!has_zero_init || out_baseimg ||
>> -                    is_allocated_sectors_min(buf1, n, &n1, min_sparse)) {
>> -                    ret = bdrv_write(out_bs, sector_num, buf1, n1);
>> +                int allocated = is_allocated_sectors_min(buf1, n, &n1, 
>> min_sparse);
>> +                if (!has_zero_init || out_baseimg || allocated) {
>> +                    if (allocated || out_baseimg) {
>> +                        ret = bdrv_write(out_bs, sector_num, buf1, n1);
>> +                    } else {
>> +                        ret = bdrv_write_zeroes(out_bs, sector_num, n1);
> I think it should still do the write only if !has_zero_init.
With this I am still in trouble with iSCSI, but Kevin pointed out another
possible solution for the allocating everything problem.

a) let iscsi_create discard the whole device if lbpz && lbprz
b) return 1 for has_zero_init if lbprz.

What do you think?

Peter
>
> Paolo
>
>> +                    }
>>                      if (ret < 0) {
>>                          error_report("error while writing sector %" PRId64
>>                                       ": %s", sector_num, strerror(-ret));
>>