Theodore Ts'o wrote:

> On Wed, Jan 26, 2005 at 11:22:39PM -0800, pmeda@akamai.com wrote:
> >
> > Apply ext3 speedups added by Jan Kara to ext2.
> > Reference: http://linus.bkbits.net:8080/linux-2.5/gnupatch@41f127f2jwYahmKm0eWTJNpYcSyhPw
> >
>
> This patch isn't right, as it causes ext2_sparse_group(1) to return 0
> instead of 1.  Block groups number 0 and 1 must always contain a
> superblock.
>
> >  static int ext2_group_sparse(int group)
> >  {
> > +     if (group <= 0)
> > +             return 1;
>
> Change this to be:
>
> +       if (group <= 1)
> +               return 1;
>
> and it should fix the patch (as well as be similar to the ext3
> mainline).  With this change,
>
> Acked-by: "Theodore Ts'o" <tytso@mit.edu>

 Thanks for correction!  I made one more attempt to improve it.
 Please look at the attached patch.

  - Folded all three root checkings for 3,  5 and 7 into one loop.
  -  Short cut the loop with 3**n < 5 **n < 7**n logic.
  -  Even numbers can be ruled out.

  Tested with  user space programs.


Thanks,
Prasanna.