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

[Paolo Bonzini <pbonzini@redhat.com>]

Il 22/06/2013 22:58, Peter Lieven ha scritto:
> Signed-off-by: Peter Lieven <pl@kamp.de>
> ---
>  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.

Paolo

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