Add an optimization to pthread aio writes to also do fsync if requested.

Should help by ensuring complete writes done in sub-thread, not in
the main thread.

source3/modules/vfs_aio_pthread.c

@@ -40,6 +40,7 @@ struct aio_private_data {
 	int ret_errno;
 	bool cancelled;
 	bool write_command;
+	bool flush_write;
 };
 
 /* List of outstanding requests we have. */
@@ -115,6 +116,14 @@ static void aio_worker(void *private_data)
 					(const void *)pd->aiocb->aio_buf,
 					pd->aiocb->aio_nbytes);
 		}
+		if (pd->ret_size != -1 && pd->flush_write) {
+			/*
+			 * Optimization - flush if requested.
+			 * Ignore error as upper layer will
+			 * also do this.
+			 */
+			(void)fsync(pd->aiocb->aio_fildes);
+		}
 	} else {
 		pd->ret_size = sys_pread(pd->aiocb->aio_fildes,
 				(void *)pd->aiocb->aio_buf,
@@ -229,6 +238,12 @@ static int aio_pthread_write(struct vfs_handle_struct *handle,
 	}
 
 	pd->write_command = true;
+	if (lp_strict_sync(SNUM(fsp->conn)) &&
+			(lp_syncalways(SNUM(fsp->conn)) ||
+				aio_write_through_requested(aio_ex))) {
+		pd->flush_write = true;
+	}
+
 
 	ret = pthreadpool_add_job(pool, pd->jobid, aio_worker, (void *)pd);
 	if (ret) {

source3/smbd/aio.c

@@ -52,6 +52,15 @@ struct aio_extra {
 	int (*handle_completion)(struct aio_extra *ex, int errcode);
 };
 
+/****************************************************************************
+ Accessor function to return write_through state.
+*****************************************************************************/
+
+bool aio_write_through_requested(struct aio_extra *aio_ex)
+{
+	return aio_ex->write_through;
+}
+
 /****************************************************************************
  Initialize the signal handler for aio read/write.
 *****************************************************************************/

source3/smbd/proto.h

@@ -64,6 +64,7 @@ void srv_set_signing(struct smbd_server_connection *conn,
 
 /* The following definitions come from smbd/aio.c  */
 
+bool aio_write_through_requested(struct aio_extra *aio_ex);
 bool initialize_async_io_handler(void);
 NTSTATUS schedule_aio_read_and_X(connection_struct *conn,
 			     struct smb_request *req,