What's a file?

Reading

             struct timespec            i_atime;
             struct timespec            i_mtime;        2007-11-22 21:01 
             struct timespec            i_ctime;

After a successful read or write, the kernel updates the i_atime

After a successful write, it updates the i_mtime

And possibly some other stuff too:

             loff_t                     i_size;        4096
             blkcnt_t           i_blocks;