5 files changed, 9 insertions, 0 deletions
diff --git a/block/qcow2.c b/block/qcow2.c
index 8e2b6c7..41e454a 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -1893,6 +1893,8 @@ static coroutine_fn int qcow2_co_flush_to_os(BlockDriverState *bs)
 static int qcow2_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
 {
     BDRVQcowState *s = bs->opaque;
+    bdi->unallocated_blocks_are_zero = true;
+    bdi->can_write_zeroes_with_unmap = (s->qcow_version >= 3);
     bdi->cluster_size = s->cluster_size;
     bdi->vm_state_offset = qcow2_vm_state_offset(s);
     return 0;
diff --git a/block/qed.c b/block/qed.c
index adc2736..59516a5 100644
--- a/block/qed.c
+++ b/block/qed.c
@@ -1475,6 +1475,8 @@ static int bdrv_qed_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
     memset(bdi, 0, sizeof(*bdi));
     bdi->cluster_size = s->header.cluster_size;
     bdi->is_dirty = s->header.features & QED_F_NEED_CHECK;
+    bdi->unallocated_blocks_are_zero = true;
+    bdi->can_write_zeroes_with_unmap = true;
     return 0;
 }
 
diff --git a/block/vdi.c b/block/vdi.c
index b6ec002..2d7490f 100644
--- a/block/vdi.c
+++ b/block/vdi.c
@@ -331,6 +331,7 @@ static int vdi_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
     logout("\n");
     bdi->cluster_size = s->block_size;
     bdi->vm_state_offset = 0;
+    bdi->unallocated_blocks_are_zero = true;
     return 0;
 }
 
diff --git a/block/vhdx.c b/block/vhdx.c
index ed6fa53..67bbe10 100644
--- a/block/vhdx.c
+++ b/block/vhdx.c
@@ -1049,6 +1049,9 @@ static int vhdx_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
 
     bdi->cluster_size = s->block_size;
 
+    bdi->unallocated_blocks_are_zero =
+        (s->params.data_bits & VHDX_PARAMS_HAS_PARENT) == 0;
+
     return 0;
 }
 
diff --git a/block/vpc.c b/block/vpc.c
index 551876f..1d326cb 100644
--- a/block/vpc.c
+++ b/block/vpc.c
@@ -464,6 +464,7 @@ static int vpc_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
         bdi->cluster_size = s->block_size;
     }
 
+    bdi->unallocated_blocks_are_zero = true;
     return 0;
 }