debugfs fill_bgs command?

debugfs fill_bgs command?

[Eric Sandeen]

I was wondering if others think it would be useful to have a "fill_bgs"
command in debugfs; this would (minimally) mark the lower X bgs as full
for both inodes & blocks (possibly either/or), to allow testing the
higher block groups.  I'm using a hacked up version of this to do a
little ext3 testing above 8T.  Given that this would really only be a
testing option in nature, would it be accepted into e2fsprogs?  I'd
probably need some sort of "unfill" command as well, to put the bg
counters back where they should be; probably by actually reading the
bitmaps.  This way fsck would still find a consistent filesystem...

I had originally written a set_bg_field function too, to go with inode &
sb variants, though for marking the first few thousand bg's it was going
to get a bit tedious... :)

Thoughts?

Thanks,
-Eric

Re: debugfs fill_bgs command?

[Andreas Dilger]

On Apr 11, 2007  15:17 -0500, Eric Sandeen wrote:
> I was wondering if others think it would be useful to have a "fill_bgs"
> command in debugfs; this would (minimally) mark the lower X bgs as full
> for both inodes & blocks (possibly either/or), to allow testing the
> higher block groups.  I'm using a hacked up version of this to do a
> little ext3 testing above 8T.  Given that this would really only be a
> testing option in nature, would it be accepted into e2fsprogs?  I'd
> probably need some sort of "unfill" command as well, to put the bg
> counters back where they should be; probably by actually reading the
> bitmaps.  This way fsck would still find a consistent filesystem...
> 
> I had originally written a set_bg_field function too, to go with inode &
> sb variants, though for marking the first few thousand bg's it was going
> to get a bit tedious... :)

Try "mke2fs -O lazy_bg XXX" and be happy.  Can be used on any kernel as
it is a COMPAT feature and marks all but first and last groups as full.

Cheers, Andreas
--
Andreas Dilger
Principal Software Engineer
Cluster File Systems, Inc.

Re: debugfs fill_bgs command?

[Eric Sandeen]

Andreas Dilger wrote:

> Try "mke2fs -O lazy_bg XXX" and be happy.  Can be used on any kernel as
> it is a COMPAT feature and marks all but first and last groups as full.

Ugh, how'd I miss that.  :)

Thanks...

-Eric