diff --git a/block/nfs.c b/block/nfs.c
index 351dc6e..006045d 100644
--- a/block/nfs.c
+++ b/block/nfs.c
@@ -726,10 +726,8 @@
     if (task->ret < 0) {
         error_report("NFS Error: %s", nfs_get_error(nfs));
     }
-
-    /* Set task->complete before reading bs->wakeup.  */
-    qatomic_mb_set(&task->complete, 1);
-    bdrv_wakeup(task->bs);
+    replay_bh_schedule_oneshot_event(task->client->aio_context,
+                                     nfs_co_generic_bh_cb, task);
 }
 
 static int64_t coroutine_fn nfs_co_get_allocated_file_size(BlockDriverState *bs)
@@ -743,15 +741,19 @@
         return client->st_blocks * 512;
     }
 
-    task.bs = bs;
+    nfs_co_init_task(bs, &task);
     task.st = &st;
-    if (nfs_fstat_async(client->context, client->fh, nfs_get_allocated_file_size_cb,
-                        &task) != 0) {
-        return -ENOMEM;
-    }
+    WITH_QEMU_LOCK_GUARD(&client->mutex) {
+        if (nfs_fstat_async(client->context, client->fh, nfs_get_allocated_file_size_cb,
+                            &task) != 0) {
+            return -ENOMEM;
+        }
 
-    nfs_set_events(client);
-    BDRV_POLL_WHILE(bs, !task.complete);
+        nfs_set_events(client);
+    }
+    while (!task.complete) {
+        qemu_coroutine_yield();
+    }
 
     return (task.ret < 0 ? task.ret : st.st_blocks * 512);
 }