Now block-copy will crash if user don't set progress meter by
block_copy_set_progress_meter(). copy-before-write filter will be used
in separate of backup job, and it doesn't want any progress meter (for
now). So, allow not setting it.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
---
 block/block-copy.c | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/block/block-copy.c b/block/block-copy.c
index b0e0a38330..975f9986a4 100644
--- a/block/block-copy.c
+++ b/block/block-copy.c
@@ -291,9 +291,11 @@ static void coroutine_fn block_copy_task_end(BlockCopyTask *task, int ret)
         bdrv_set_dirty_bitmap(task->s->copy_bitmap, task->offset, task->bytes);
     }
     QLIST_REMOVE(task, list);
-    progress_set_remaining(task->s->progress,
-                           bdrv_get_dirty_count(task->s->copy_bitmap) +
-                           task->s->in_flight_bytes);
+    if (task->s->progress) {
+        progress_set_remaining(task->s->progress,
+                               bdrv_get_dirty_count(task->s->copy_bitmap) +
+                               task->s->in_flight_bytes);
+    }
     qemu_co_queue_restart_all(&task->wait_queue);
 }
 
@@ -593,7 +595,7 @@ static coroutine_fn int block_copy_task_entry(AioTask *task)
                 t->call_state->ret = ret;
                 t->call_state->error_is_read = error_is_read;
             }
-        } else {
+        } else if (s->progress) {
             progress_work_done(s->progress, t->bytes);
         }
     }
@@ -699,9 +701,11 @@ int64_t block_copy_reset_unallocated(BlockCopyState *s,
     if (!ret) {
         qemu_co_mutex_lock(&s->lock);
         bdrv_reset_dirty_bitmap(s->copy_bitmap, offset, bytes);
-        progress_set_remaining(s->progress,
-                               bdrv_get_dirty_count(s->copy_bitmap) +
-                               s->in_flight_bytes);
+        if (s->progress) {
+            progress_set_remaining(s->progress,
+                                   bdrv_get_dirty_count(s->copy_bitmap) +
+                                   s->in_flight_bytes);
+        }
         qemu_co_mutex_unlock(&s->lock);
     }
 
-- 
2.29.2