On 9/18/23 20:00, Denis V. Lunev wrote:
> * Discarding with backing stores is not supported by the format.
> * There is no buffering/queueing of the discard operation.
> * Only operations aligned to the cluster are supported.
>
> Signed-off-by: Denis V. Lunev <den@openvz.org>
> ---
> block/parallels.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 46 insertions(+)
>
> diff --git a/block/parallels.c b/block/parallels.c
> index d9d36c514b..1ef23f6669 100644
> --- a/block/parallels.c
> +++ b/block/parallels.c
> @@ -537,6 +537,51 @@ parallels_co_readv(BlockDriverState *bs, int64_t sector_num, int nb_sectors,
> return ret;
> }
>
> +
> +static int coroutine_fn
> +parallels_co_pdiscard(BlockDriverState *bs, int64_t offset, int64_t bytes)
> +{
> + int ret = 0;
> + uint32_t cluster, count;
> + BDRVParallelsState *s = bs->opaque;
> +
> + /*
> + * The image does not support ZERO mark inside the BAT, which means that
> + * stale data could be exposed from the backing file.
> + */
> + if (bs->backing) {
> + return -ENOTSUP;
> + }
> +
> + if (!QEMU_IS_ALIGNED(offset, s->cluster_size)) {
> + return -ENOTSUP;
> + } else if (!QEMU_IS_ALIGNED(bytes, s->cluster_size)) {
> + return -ENOTSUP;
> + }
> +
> + cluster = offset / s->cluster_size;
> + count = bytes / s->cluster_size;
> +
> + qemu_co_mutex_lock(&s->lock);
> + for (; count > 0; cluster++, count--) {
> + int64_t host_off = bat2sect(s, cluster) << BDRV_SECTOR_BITS;
> + if (host_off == 0) {
> + continue;
> + }
> +
> + ret = bdrv_co_pdiscard(bs->file, host_off, s->cluster_size);
> + if (ret < 0) {
> + goto done;
> + }
> +
> + parallels_set_bat_entry(s, cluster, 0);
> + bitmap_clear(s->used_bmap, host_cluster_index(s, host_off), 1);
> + }
> +done:
> + qemu_co_mutex_unlock(&s->lock);
> + return ret;
> +}
> +
> static void parallels_check_unclean(BlockDriverState *bs,
> BdrvCheckResult *res,
> BdrvCheckMode fix)
> @@ -1417,6 +1462,7 @@ static BlockDriver bdrv_parallels = {
> .bdrv_co_create = parallels_co_create,
> .bdrv_co_create_opts = parallels_co_create_opts,
> .bdrv_co_check = parallels_co_check,
> + .bdrv_co_pdiscard = parallels_co_pdiscard,
> };
>
> static void bdrv_parallels_init(void)
Reviewed-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
--
Best regards,
Alexander Ivanov