MDEV-17845 Extreme high open file limit used

SHOW STATUS LIKE 'Open_files' was showing 18446744073709551615

my_file_opened used statistic_increment/statistic_decrement,
so one-off errors were normal and expected. But they confused
monitoring tools, so let's move my_file_opened to use atomics.

3 files changed, 6 insertions, 8 deletions

diff --git a/mysys/my_fopen.c b/mysys/my_fopen.c
index fbd84049700..e33d9d67925 100644
--- a/mysys/my_fopen.c
+++ b/mysys/my_fopen.c
@@ -223,7 +223,7 @@ FILE *my_fdopen(File Filedes, const char *name, int Flags, myf MyFlags)
     {
       if (my_file_info[Filedes].type != UNOPEN)
       {
-        statistic_decrement(my_file_opened, &THR_LOCK_open);		/* File is opened with my_open ! */
+        thread_safe_decrement32(&my_file_opened);       /* File is opened with my_open ! */
       }
       else
       {
diff --git a/mysys/my_open.c b/mysys/my_open.c
index 92e46610100..aa3b0448cdb 100644
--- a/mysys/my_open.c
+++ b/mysys/my_open.c
@@ -105,7 +105,7 @@ int my_close(File fd, myf MyFlags)
   {
     my_free(name);
   }
-  statistic_decrement(my_file_opened, &THR_LOCK_open);
+  thread_safe_decrement32(&my_file_opened);
   DBUG_RETURN(err);
 } /* my_close */
 
@@ -133,13 +133,10 @@ File my_register_filename(File fd, const char *FileName, enum file_type
   DBUG_ENTER("my_register_filename");
   if ((int) fd >= MY_FILE_MIN)
   {
+    thread_safe_increment32(&my_file_opened);
     if ((uint) fd >= my_file_limit)
-    {
-      statistic_increment(my_file_opened,&THR_LOCK_open);
-      DBUG_RETURN(fd);				/* safeguard */
-    }
+      DBUG_RETURN(fd);
     my_file_info[fd].name = (char*) my_strdup(FileName, MyFlags);
-    statistic_increment(my_file_opened,&THR_LOCK_open);
     statistic_increment(my_file_total_opened,&THR_LOCK_open);
     my_file_info[fd].type = type_of_file;
     DBUG_PRINT("exit",("fd: %d",fd));
diff --git a/mysys/my_static.c b/mysys/my_static.c
index f2a9fbb7335..a8f520e656a 100644
--- a/mysys/my_static.c
+++ b/mysys/my_static.c
@@ -31,7 +31,7 @@ char *mysql_data_home= (char*) ".";
 const char      *my_progname= NULL, *my_progname_short= NULL;
 char		curr_dir[FN_REFLEN]= {0},
 		home_dir_buff[FN_REFLEN]= {0};
-ulong		my_stream_opened=0,my_file_opened=0, my_tmp_file_created=0;
+ulong		my_stream_opened=0,my_tmp_file_created=0;
 ulong           my_file_total_opened= 0;
 int		my_umask=0664, my_umask_dir=0777;
 
@@ -39,6 +39,7 @@ myf             my_global_flags= 0;
 my_bool         my_assert_on_error= 0;
 struct st_my_file_info my_file_info_default[MY_NFILE];
 uint   my_file_limit= MY_NFILE;
+int32           my_file_opened=0;
 struct st_my_file_info *my_file_info= my_file_info_default;
 
 	/* From mf_brkhant */