On Mon, Mar 23, 2015 at 12:46:09PM +0800, Fam Zheng wrote:
> @@ -3435,6 +3446,10 @@ static int coroutine_fn
> bdrv_co_do_pwritev(BlockDriverState *bs,
> bytes = ROUND_UP(bytes, align);
> }
>
> + if (use_local_qiov) {
> + /* Local buffer may have non-zero data. */
> + flags &= ~BDRV_REQ_ZERO_WRITE;
> + }
> ret = bdrv_aligned_pwritev(bs, &req, offset, bytes,
> use_local_qiov ? &local_qiov : qiov,
> flags);
> @@ -3475,14 +3490,32 @@ int coroutine_fn
> bdrv_co_write_zeroes(BlockDriverState *bs,
> int64_t sector_num, int nb_sectors,
> BdrvRequestFlags flags)
> {
> + int ret;
> +
> trace_bdrv_co_write_zeroes(bs, sector_num, nb_sectors, flags);
>
> - if (!(bs->open_flags & BDRV_O_UNMAP)) {
> - flags &= ~BDRV_REQ_MAY_UNMAP;
> - }
Why is it okay to drop this when the request is aligned?
> + if (bdrv_req_is_aligned(bs, sector_num << BDRV_SECTOR_BITS,
> + nb_sectors << BDRV_SECTOR_BITS)) {
> + ret = bdrv_co_do_writev(bs, sector_num, nb_sectors, NULL,
> + BDRV_REQ_ZERO_WRITE | flags);
> + } else {
pgpohTxuQtrgo.pgp
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