@@ -2920,6 +2920,11 @@ int bdrv_has_zero_init(BlockDriverState *bs)
{
assert(bs->drv);
+ /* If BS is a copy on write image, it is initialized to
+ the contents of the base image, which may not be zeroes. */
+ if (bs->backing_hd) {
+ return 0;
+ }
if (bs->drv->bdrv_has_zero_init) {
return bs->drv->bdrv_has_zero_init(bs);
}
@@ -1504,14 +1504,7 @@ static int img_convert(int argc, char **argv)
should add a specific call to have the info to go faster */
buf1 = buf;
while (n > 0) {
- /* If the output image is being created as a copy on write image,
- copy all sectors even the ones containing only NUL bytes,
- because they may differ from the sectors in the base image.
-
- 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 ||
+ if (!has_zero_init ||
is_allocated_sectors_min(buf1, n, &n1, min_sparse)) {
ret = bdrv_write(out_bs, sector_num, buf1, n1);
if (ret < 0) {
This helps implementing is_allocated on top of get_block_status. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> --- block.c | 5 +++++ qemu-img.c | 9 +-------- 2 files changed, 6 insertions(+), 8 deletions(-)