BUG#22301 ndb: File_class::size() is not thread safe

ndb/include/logger/FileLogHandler.hpp:
  use off_t for file offset
ndb/include/util/File.hpp:
  use off_t for returning file offset (size)
ndb/src/common/util/File.cpp:
  make File_class::size(FILE*) safe when having multiple threads writing to
  the file

ndb/include/logger/FileLogHandler.hpp

@@ -102,7 +102,7 @@ private:
   bool setMaxFiles(const BaseString &files);
   
   int m_maxNoFiles;
-  long m_maxFileSize;
+  off_t m_maxFileSize;
   unsigned int m_maxLogEntries;
   File_class* m_pLogFile;
 };

ndb/include/util/File.hpp

@@ -50,7 +50,7 @@ public:
    * @param f a pointer to a FILE descriptor.
    * @return the size of the file.
    */
-  static long size(FILE* f);
+  static off_t size(FILE* f);
 
   /**
    * Renames a file.
@@ -182,7 +182,7 @@ public:
    *
    * @return the file size.
    */
-  long size() const;
+  off_t size() const;
 
   /**
    * Returns the filename.

ndb/src/common/util/File.cpp

@@ -45,17 +45,16 @@ File_class::exists(const char* aFileName)
   return (my_stat(aFileName, &stmp, MYF(0))!=NULL);
 }
 
-long
+off_t
 File_class::size(FILE* f)
 {
-  long cur_pos = 0, length = 0;
-  
-  cur_pos = ::ftell(f);
-  ::fseek(f, 0, SEEK_END); 
-  length = ::ftell(f); 
-  ::fseek(f, cur_pos, SEEK_SET); // restore original position
+  MY_STAT s;
+
+  // Note that my_fstat behaves *differently* than my_stat. ARGGGHH!
+  if(my_fstat(::fileno(f), &s, MYF(0)))
+    return 0;
 
-  return length;
+  return s.st_size;
 }
 
 bool 
@@ -168,8 +167,8 @@ File_class::writeChar(const char* buf)
 {
   return writeChar(buf, 0, ::strlen(buf));
 }
-   
-long 
+
+off_t
 File_class::size() const
 {
   return File_class::size(m_file);