librbd: potentially delay completion of image dispatcher spec

If an AioCompletion is being completed for an external API user, ensure
that the completion of image dispatcher finalizer does not race with the
potential to close the image.

Signed-off-by: Jason Dillaman <dillaman@redhat.com>

diff --git a/src/librbd/io/AioCompletion.cc b/src/librbd/io/AioCompletion.cc
index f6015b8a942d8c6906e9dd1a18f50201bf50e3ae..cd5df0e7147e81f18258997ffe22e4e947e1635f 100644 (file)
--- a/src/librbd/io/AioCompletion.cc
+++ b/src/librbd/io/AioCompletion.cc
@@ -114,10 +114,6 @@ void AioCompletion::complete() {
     notify_callbacks_complete();
   }
 
-  if (image_dispatcher_ctx != nullptr) {
-    image_dispatcher_ctx->complete(rval);
-  }
-
   tracepoint(librbd, aio_complete_exit);
 }
 
@@ -275,6 +271,10 @@ void AioCompletion::notify_callbacks_complete() {
     cond.notify_all();
   }
 
+  if (image_dispatcher_ctx != nullptr) {
+    image_dispatcher_ctx->complete(rval);
+  }
+
   // note: possible for image to be closed after op marked finished
   if (async_op.started()) {
     async_op.finish_op();