TSAN: unprotected global variable

WARNING: ThreadSanitizer: data race (pid=1510842)
  Write of size 8 at 0x0000067b1e98 by main thread:
    #0 os_file_pwrite(IORequest const&, int, unsigned char const*, unsigned long, unsigned long, dberr_t*) /storage/innobase/os/os0file.cc:2928:2 (mariadbd+0x234c5ac)
    #1 os_file_write_func(IORequest const&, char const*, int, void const*, unsigned long, unsigned long) /storage/innobase/os/os0file.cc:2963:20 (mariadbd+0x234c019)
    #2 file_os_io::write(char const*, unsigned long, st_::span<unsigned char const>) /storage/innobase/log/log0log.cc:320:10 (mariadbd+0x22eaa50)
    #3 log_file_t::write(unsigned long, st_::span<unsigned char const>) /storage/innobase/log/log0log.cc:434:18 (mariadbd+0x22eb1d8)
    #4 log_t::file::write(unsigned long, st_::span<unsigned char>) /storage/innobase/log/log0log.cc:496:29 (mariadbd+0x22ebb55)
    #5 log_write_buf(unsigned char*, unsigned long, unsigned long, unsigned long, unsigned long) /storage/innobase/log/log0log.cc:614:14 (mariadbd+0x22f1b51)
    #6 log_write(bool) /storage/innobase/log/log0log.cc:755:2 (mariadbd+0x22ed2ec)
    #7 log_write_up_to(unsigned long, bool, bool, completion_callback const*) /storage/innobase/log/log0log.cc:817:5 (mariadbd+0x22eca44)
    #8 log_checkpoint_low(unsigned long, unsigned long) /storage/innobase/buf/buf0flu.cc:1734:5 (mariadbd+0x20d37c1)
    #9 log_checkpoint() /storage/innobase/buf/buf0flu.cc:1787:10 (mariadbd+0x20cd155)
    #10 buf_flush_wait_flushed(unsigned long) /storage/innobase/buf/buf0flu.cc:1867:5 (mariadbd+0x20ccf8f)
    #11 log_make_checkpoint() /storage/innobase/buf/buf0flu.cc:1793:3 (mariadbd+0x20cc4c9)
    #12 buf_dblwr_t::create() /storage/innobase/buf/buf0dblwr.cc:216:3 (mariadbd+0x209076a)
    #13 srv_start(bool) /storage/innobase/srv/srv0start.cc:1685:20 (mariadbd+0x256b4aa)
    #14 innodb_init(void*) /storage/innobase/handler/ha_innodb.cc:4188:8 (mariadbd+0x1ed40da)
    #15 ha_initialize_handlerton(st_plugin_int*) /sql/handler.cc:659:31 (mariadbd+0xf7c2b6)
    #16 plugin_initialize(st_mem_root*, st_plugin_int*, int*, char**, bool) /sql/sql_plugin.cc:1463:9 (mariadbd+0x160fedb)
    #17 plugin_init(int*, char**, int) /sql/sql_plugin.cc:1756:15 (mariadbd+0x160f53f)
    #18 init_server_components() /sql/mysqld.cc:5043:7 (mariadbd+0xd71462)
    #19 mysqld_main(int, char**) /sql/mysqld.cc:5655:7 (mariadbd+0xd6ae87)
    #20 main /sql/main.cc:34:10 (mariadbd+0xd661c8)

  Previous write of size 8 at 0x0000067b1e98 by thread T3:
    #0 os_file_pwrite(IORequest const&, int, unsigned char const*, unsigned long, unsigned long, dberr_t*) /storage/innobase/os/os0file.cc:2928:2 (mariadbd+0x234c5ac)
    #1 os_file_write_func(IORequest const&, char const*, int, void const*, unsigned long, unsigned long) /storage/innobase/os/os0file.cc:2963:20 (mariadbd+0x234c019)
    #2 file_os_io::write(char const*, unsigned long, st_::span<unsigned char const>) /storage/innobase/log/log0log.cc:320:10 (mariadbd+0x22eaa50)
    #3 log_file_t::write(unsigned long, st_::span<unsigned char const>) /storage/innobase/log/log0log.cc:434:18 (mariadbd+0x22eb1d8)
    #4 log_t::file::write(unsigned long, st_::span<unsigned char>) /storage/innobase/log/log0log.cc:496:29 (mariadbd+0x22ebb55)
    #5 log_write_checkpoint_info(unsigned long) /storage/innobase/log/log0log.cc:911:14 (mariadbd+0x22edd4e)
    #6 log_checkpoint_low(unsigned long, unsigned long) /storage/innobase/buf/buf0flu.cc:1755:3 (mariadbd+0x20d3a3d)
    #7 buf_flush_sync_for_checkpoint(unsigned long) /storage/innobase/buf/buf0flu.cc:1947:7 (mariadbd+0x20d4163)
    #8 buf_flush_page_cleaner() /storage/innobase/buf/buf0flu.cc:2186:9 (mariadbd+0x20cdab1)
    #9 void std::__invoke_impl<void, void (*)()>(std::__invoke_other, void (*&&)()) /usr/lib/gcc/x86_64-linux-gnu/11/../../../../include/c++/11/bits/invoke.h:61:14 (mariadbd+0x20c3aaa)
    #10 std::__invoke_result<void (*)()>::type std::__invoke<void (*)()>(void (*&&)()) /usr/lib/gcc/x86_64-linux-gnu/11/../../../../include/c++/11/bits/invoke.h:96:14 (mariadbd+0x20c39bd)
    #11 void std::thread::_Invoker<std::tuple<void (*)()> >::_M_invoke<0ul>(std::_Index_tuple<0ul>) /usr/lib/gcc/x86_64-linux-gnu/11/../../../../include/c++/11/bits/std_thread.h:253:13 (mariadbd+0x20c3965)
    #12 std::thread::_Invoker<std::tuple<void (*)()> >::operator()() /usr/lib/gcc/x86_64-linux-gnu/11/../../../../include/c++/11/bits/std_thread.h:260:11 (mariadbd+0x20c3905)
    #13 std::thread::_State_impl<std::thread::_Invoker<std::tuple<void (*)()> > >::_M_run() /usr/lib/gcc/x86_64-linux-gnu/11/../../../../include/c++/11/bits/std_thread.h:211:13 (mariadbd+0x20c37f9)
    #14 <null> <null> (libstdc++.so.6+0xd230f)

  Location is global 'os_n_file_writes' of size 8 at 0x0000067b1e98 (mariadbd+0x67b1e98)

  Make variable atomic.

storage/innobase/include/os0file.h

@@ -263,7 +263,7 @@ struct os_file_size_t {
 constexpr ulint OS_AIO_N_PENDING_IOS_PER_THREAD= 256;
 
 extern Atomic_counter<ulint> os_n_file_reads;
-extern ulint	os_n_file_writes;
+extern Atomic_counter<size_t> os_n_file_writes;
 extern Atomic_counter<size_t> os_n_fsyncs;
 
 /* File types for directory entry data type */

storage/innobase/os/os0file.cc

@@ -157,7 +157,7 @@ static ulint	os_innodb_umask	= 0;
 
 Atomic_counter<ulint> os_n_file_reads;
 static ulint	os_bytes_read_since_printout;
-ulint	os_n_file_writes;
+Atomic_counter<size_t> os_n_file_writes;
 Atomic_counter<size_t> os_n_fsyncs;
 static ulint	os_n_file_reads_old;
 static ulint	os_n_file_writes_old;
@@ -3924,12 +3924,11 @@ os_aio_print(FILE*	file)
 	fprintf(file,
 		"Pending flushes (fsync) log: " ULINTPF
 		"; buffer pool: " ULINTPF "\n"
-		ULINTPF " OS file reads, "
-		ULINTPF " OS file writes, %zu OS fsyncs\n",
+		ULINTPF " OS file reads, %zu OS file writes, %zu OS fsyncs\n",
 		log_sys.get_pending_flushes(),
 		ulint{fil_n_pending_tablespace_flushes},
 		ulint{os_n_file_reads},
-		os_n_file_writes,
+		static_cast<size_t>(os_n_file_writes),
 		static_cast<size_t>(os_n_fsyncs));
 
 	const ulint n_reads = ulint(MONITOR_VALUE(MONITOR_OS_PENDING_READS));