* 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 | 47 +++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 47 insertions(+)
diff --git a/block/parallels.c b/block/parallels.c
index 76aedfd7c4..83cb8d6722 100644
--- a/block/parallels.c
+++ b/block/parallels.c
@@ -537,6 +537,52 @@ parallels_co_readv(BlockDriverState *bs, int64_t
sector_num, int nb_sectors,
return ret;
}
+
+static int coroutine_fn GRAPH_RDLOCK_PTR
+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, cluster * s->cluster_size,
+ 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)
@@ -1409,6 +1455,7 @@ 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)