Re: Ininitial e2fsprogs TODO list (please expand)

[Andreas Dilger <adilger@sun.com>]

On Apr 15, 2008  23:35 -0500, Jose R. Santos wrote:
> On Tue, 15 Apr 2008 21:30:02 -0600
> Andreas Dilger <adilger@sun.com> wrote:
> > Something was lost in translation here.  The uninit_groups feature DOES
> > zero the inode tables by default, and marks the groups with ITABLE_ZEROED.
> > It is only if "-O uninit_groups,lazy_bg" are both given at the same time
> > that the itable is not initialized.  That is no different than if lazy_bg
> > was given by itself.
> 
> Yes, I understand this part.
>  
> > So nothing needs to be done in e2fsprogs until some time after the kernel
> > is updated to do the zeroing.
> 
> The problem is that not initializing the inode table on the uninit
> block group patch depends on a feature (lazy_bg) that Ted wants
> removed.  I believe that just removing the lazy_bg feature would be
> enough to remove this capability from the uninit patch, but was not
> entirely sure so I put the item just to keep track of it.
> 
> If lazy_bg is in fact removed from e2fsprogs, I suppose we need to add
> another item to enable lazy setup of the inode tables once the proper
> support in the kernel is establish.

Yes, the "lazy init" for uinint_groups will essentially be identical to
what we have in lazy_bg today.  So if we are disabling lazy_bg as a
user-selectable option, we should leave the code in place for later use.
I wouldn't object to requiring a user to specify "mke2fs -O FEATURE_C6"
to enable it.  That keeps it out of the hands of newbies, but leaves the
capability to test large filesystems w/o 45 minute mke2fs times.

Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.