Re: [PATCH] FLEX_BG Kernel support.

["Jose R. Santos" <jrs@us.ibm.com>]

On Tue, 11 Sep 2007 17:21:39 -0600
Andreas Dilger <adilger@clusterfs.com> wrote:

> On Sep 11, 2007  07:27 -0500, Jose R. Santos wrote:
> > On Tue, 11 Sep 2007 00:04:43 -0600
> > "Andreas Dilger" <adilger@clusterfs.com> wrote:
> > > On 9/10/07, Jose R. Santos <jrs@us.ibm.com> wrote:
> > > > @@ -1254,7 +1254,8 @@ static int ext4_check_descriptors (struct super_block * sb)
> > > >
> > > >         for (i = 0; i < sbi->s_groups_count; i++)
> > > >         {
> > > > -               if (i == sbi->s_groups_count - 1)
> > > > +               if (i == sbi->s_groups_count - 1 || EXT4_HAS_INCOMPAT_FEATURE(sb,
> > > > +                                       EXT4_FEATURE_INCOMPAT_FLEX_BG))
> > > >                         last_block = ext4_blocks_count(sbi->s_es) - 1;
> > > 
> > > No need to check this featyre for every  group, once at the beginning
> > > of the function is enough.
> > > 
> > 
> > Do you mean something like the original patch?
> > http://lists.openwall.net/linux-ext4/2007/07/12/20
> > 
> > Wouldn't we need to check all the descriptor for corruption if checksum
> > is not enable on the filesystem?
> 
> Yes, I just meant you don't need to have:
> 
> 	EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG))
> 
> for each time through the loop.  That loop is walked 8000 times per TB
> at mount, so if we can make it faster we should do so.

Good point, I'll send an updated patch.


-JRS