this patch does 2 things: a) only do additional call outs if BDRV_BLOCK_ZERO is not already set. b) use bdi.discard_zeroes to return the zero state of an unallocated block. the callout to bdrv_has_zero_init() is only valid right after bdrv_create.
Signed-off-by: Peter Lieven <p...@kamp.de> --- block.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/block.c b/block.c index 282943b..6698c10 100644 --- a/block.c +++ b/block.c @@ -3153,8 +3153,10 @@ static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs, return ret; } - if (!(ret & BDRV_BLOCK_DATA)) { - if (bdrv_has_zero_init(bs)) { + if (!(ret & BDRV_BLOCK_DATA) && !(ret & BDRV_BLOCK_ZERO)) { + BlockDriverInfo bdi; + if (bdrv_get_info(bs, &bdi) == 0 && + bdi.discard_zeroes) { ret |= BDRV_BLOCK_ZERO; } else if (bs->backing_hd) { BlockDriverState *bs2 = bs->backing_hd; -- 1.7.9.5