[PATCH 19/22] parallels: naive implementation of parallels_co_pdiscard

Denis V. Lunev posted 22 patches 8 months, 1 week ago
There is a newer version of this series
[PATCH 19/22] parallels: naive implementation of parallels_co_pdiscard
Posted by Denis V. Lunev 8 months, 1 week ago
* 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)
-- 
2.34.1
Re: [PATCH 19/22] parallels: naive implementation of parallels_co_pdiscard
Posted by Alexander Ivanov 8 months, 1 week ago
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