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Re: [Qemu-devel] [PATCH 2/7] qcow2: bdrv_co_pwritev: move encryption cod
From: |
Max Reitz |
Subject: |
Re: [Qemu-devel] [PATCH 2/7] qcow2: bdrv_co_pwritev: move encryption code out of lock |
Date: |
Thu, 27 Sep 2018 19:06:38 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.0 |
On 07.08.18 19:43, Vladimir Sementsov-Ogievskiy wrote:
> We don't need locking for encryption code.
>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
> ---
> block/qcow2.c | 20 ++++++++++++--------
> 1 file changed, 12 insertions(+), 8 deletions(-)
>
> diff --git a/block/qcow2.c b/block/qcow2.c
> index 41def07c67..65e3ca00e2 100644
> --- a/block/qcow2.c
> +++ b/block/qcow2.c
> @@ -2039,6 +2039,15 @@ static coroutine_fn int
> qcow2_co_pwritev(BlockDriverState *bs, uint64_t offset,
>
> assert((cluster_offset & 511) == 0);
>
> + ret = qcow2_pre_write_overlap_check(bs, 0,
> + cluster_offset +
> offset_in_cluster,
> + cur_bytes);
> + if (ret < 0) {
> + goto fail;
> + }
> +
> + qemu_co_mutex_unlock(&s->lock);
> +
> qemu_iovec_reset(&hd_qiov);
> qemu_iovec_concat(&hd_qiov, qiov, bytes_done, cur_bytes);
>
> @@ -2072,30 +2081,25 @@ static coroutine_fn int
> qcow2_co_pwritev(BlockDriverState *bs, uint64_t offset,
> qemu_iovec_add(&hd_qiov, cluster_data, cur_bytes);
> }
>
> - ret = qcow2_pre_write_overlap_check(bs, 0,
> - cluster_offset + offset_in_cluster, cur_bytes);
> - if (ret < 0) {
> - goto fail;
> - }
> -
> /* If we need to do COW, check if it's possible to merge the
> * writing of the guest data together with that of the COW regions.
> * If it's not possible (or not necessary) then write the
> * guest data now. */
> if (!merge_cow(offset, cur_bytes, &hd_qiov, l2meta)) {
> - qemu_co_mutex_unlock(&s->lock);
> BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
> trace_qcow2_writev_data(qemu_coroutine_self(),
> cluster_offset + offset_in_cluster);
> ret = bdrv_co_pwritev(bs->file,
> cluster_offset + offset_in_cluster,
> cur_bytes, &hd_qiov, 0);
> - qemu_co_mutex_lock(&s->lock);
> if (ret < 0) {
> + qemu_co_mutex_lock(&s->lock);
> goto fail;
There are a couple more failure places in between that probably need a
re-locking.
Otherwise, the patch looks good.
Max
> }
> }
>
> + qemu_co_mutex_lock(&s->lock);
> +
> ret = qcow2_handle_l2meta(bs, &l2meta, true);
> if (ret) {
> goto fail;
>
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