MDEV-14705: Speed up InnoDB shutdown

Suggested by Marko on github pr #576

buf_all_freed only needs to be called once, not 3 times.

buf_all_freed will always return TRUE if it returns.
It will crash if any page was not flushed so its effectively
an assert anyway.

The following calls are likely redundant and could be removed:

		fil_flush_file_spaces(FIL_TYPE_TABLESPACE);
		fil_flush_file_spaces(FIL_TYPE_LOG);

storage/innobase/log/log0log.cc

@@ -3441,23 +3441,6 @@ logs_empty_and_mark_files_at_shutdown(void)
 
 		mutex_exit(&log_sys->mutex);
 
-		fil_flush_file_spaces(FIL_TABLESPACE);
-		fil_flush_file_spaces(FIL_LOG);
-
-		/* The call fil_write_flushed_lsn_to_data_files() will
-		bypass the buffer pool: therefore it is essential that
-		the buffer pool has been completely flushed to disk! */
-
-		if (!buf_all_freed()) {
-			if (srv_print_verbose_log && count > 600) {
-				ib_logf(IB_LOG_LEVEL_INFO,
-					"Waiting for dirty buffer pages"
-					" to be flushed");
-				count = 0;
-			}
-
-			goto loop;
-		}
 	} else {
 		lsn = srv_start_lsn;
 	}
@@ -3468,8 +3451,7 @@ logs_empty_and_mark_files_at_shutdown(void)
 	srv_thread_type	type = srv_get_active_thread_type();
 	ut_a(type == SRV_NONE);
 
-	bool	freed = buf_all_freed();
-	ut_a(freed);
+	buf_all_freed();
 
 	ut_a(lsn == log_sys->lsn);
 
@@ -3499,9 +3481,6 @@ logs_empty_and_mark_files_at_shutdown(void)
 	type = srv_get_active_thread_type();
 	ut_a(type == SRV_NONE);
 
-	freed = buf_all_freed();
-	ut_a(freed);
-
 	ut_a(lsn == log_sys->lsn);
 }
 

storage/xtradb/log/log0log.cc

@@ -3758,23 +3758,6 @@ logs_empty_and_mark_files_at_shutdown(void)
 
 		mutex_exit(&log_sys->mutex);
 
-		fil_flush_file_spaces(FIL_TABLESPACE);
-		fil_flush_file_spaces(FIL_LOG);
-
-		/* The call fil_write_flushed_lsn_to_data_files() will
-		bypass the buffer pool: therefore it is essential that
-		the buffer pool has been completely flushed to disk! */
-
-		if (!buf_all_freed()) {
-			if (srv_print_verbose_log && count > 600) {
-				ib_logf(IB_LOG_LEVEL_INFO,
-					"Waiting for dirty buffer pages"
-					" to be flushed");
-				count = 0;
-			}
-
-			goto loop;
-		}
 	} else {
 		lsn = srv_start_lsn;
 	}
@@ -3791,8 +3774,7 @@ logs_empty_and_mark_files_at_shutdown(void)
 	srv_thread_type	type = srv_get_active_thread_type();
 	ut_a(type == SRV_NONE);
 
-	bool	freed = buf_all_freed();
-	ut_a(freed);
+	buf_all_freed();
 
 	ut_a(lsn == log_sys->lsn);
 	ut_ad(srv_force_recovery >= SRV_FORCE_NO_LOG_REDO
@@ -3824,9 +3806,6 @@ logs_empty_and_mark_files_at_shutdown(void)
 	type = srv_get_active_thread_type();
 	ut_a(type == SRV_NONE);
 
-	freed = buf_all_freed();
-	ut_a(freed);
-
 	ut_a(lsn == log_sys->lsn);
 }