vdi: Fix .bdrv_has_zero_init()

Static VDI images cannot guarantee to be zero-initialized.  If the image
has been statically allocated, forward the call to the underlying
storage node.

Reported-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Stefan Weil <sw@weilnetz.de>
Acked-by: Stefano Garzarella <sgarzare@redhat.com>
Tested-by: Stefano Garzarella <sgarzare@redhat.com>
Message-id: 20190724171239.8764-8-mreitz@redhat.com
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>

block/vdi.c

@@ -988,6 +988,17 @@ static void vdi_close(BlockDriverState *bs)
     error_free(s->migration_blocker);
 }
 
+static int vdi_has_zero_init(BlockDriverState *bs)
+{
+    BDRVVdiState *s = bs->opaque;
+
+    if (s->header.image_type == VDI_TYPE_STATIC) {
+        return bdrv_has_zero_init(bs->file->bs);
+    } else {
+        return 1;
+    }
+}
+
 static QemuOptsList vdi_create_opts = {
     .name = "vdi-create-opts",
     .head = QTAILQ_HEAD_INITIALIZER(vdi_create_opts.head),
@@ -1028,7 +1039,7 @@ static BlockDriver bdrv_vdi = {
     .bdrv_child_perm          = bdrv_format_default_perms,
     .bdrv_co_create      = vdi_co_create,
     .bdrv_co_create_opts = vdi_co_create_opts,
-    .bdrv_has_zero_init = bdrv_has_zero_init_1,
+    .bdrv_has_zero_init  = vdi_has_zero_init,
     .bdrv_co_block_status = vdi_co_block_status,
     .bdrv_make_empty = vdi_make_empty,