Merge pull request ceph#58591 from idryomov/wip-aio-completion-prep-for-atomic-wait

librbd: fix inconsistency between AioCompletion is_complete() and wait_for_complete()

Reviewed-by: N Balachandran <[email protected]>
Reviewed-by: Ramana Raja <[email protected]>

Author: idryomov

src/librbd/io/AioCompletion.cc

@@ -97,18 +97,15 @@ void AioCompletion::complete() {
     }
   }
 
-  state = AIO_STATE_CALLBACK;
   if (complete_cb) {
     if (external_callback) {
       complete_external_callback();
     } else {
       complete_cb(rbd_comp, complete_arg);
-      complete_event_socket();
-      notify_callbacks_complete();
+      mark_complete_and_notify();
     }
   } else {
-    complete_event_socket();
-    notify_callbacks_complete();
+    mark_complete_and_notify();
   }
 
   tracepoint(librbd, aio_complete_exit);
@@ -240,7 +237,7 @@ void AioCompletion::complete_request(ssize_t r)
 
 bool AioCompletion::is_complete() {
   tracepoint(librbd, aio_is_complete_enter, this);
-  bool done = (this->state != AIO_STATE_PENDING);
+  bool done = (this->state == AIO_STATE_COMPLETE);
   tracepoint(librbd, aio_is_complete_exit, done);
   return done;
 }
@@ -259,21 +256,18 @@ void AioCompletion::complete_external_callback() {
   // from multiple librbd-internal threads.
   boost::asio::dispatch(ictx->asio_engine->get_api_strand(), [this]() {
       complete_cb(rbd_comp, complete_arg);
-      complete_event_socket();
-      notify_callbacks_complete();
+      mark_complete_and_notify();
       put();
     });
 }
 
-void AioCompletion::complete_event_socket() {
+void AioCompletion::mark_complete_and_notify() {
+  state = AIO_STATE_COMPLETE;
+
   if (ictx != nullptr && event_notify && ictx->event_socket.is_valid()) {
     ictx->event_socket_completions.push(this);
     ictx->event_socket.notify();
   }
-}
-
-void AioCompletion::notify_callbacks_complete() {
-  state = AIO_STATE_COMPLETE;
 
   {
     std::unique_lock<std::mutex> locker(lock);

src/librbd/io/AioCompletion.h

@@ -40,7 +40,6 @@ namespace io {
 struct AioCompletion {
   typedef enum {
     AIO_STATE_PENDING = 0,
-    AIO_STATE_CALLBACK,
     AIO_STATE_COMPLETE,
   } aio_state_t;
 
@@ -180,8 +179,7 @@ struct AioCompletion {
 private:
   void queue_complete();
   void complete_external_callback();
-  void complete_event_socket();
-  void notify_callbacks_complete();
+  void mark_complete_and_notify();
 };
 
 class C_AioRequest : public Context {