Block file system lock?

Can the following calls be blocked? for example due to some Windows I / O conflicts (like writing to a file at the same time) or something else?

recursive_directory_iterator++
file_size
last_write_time

      

        
        
        
      

    

I have a function that uses them which for some reason intermittently have very long execution times (maybe something else, I just want to make sure the problem doesn't lie here).