debugfs fill_bgs command?

[Eric Sandeen <sandeen@redhat.com>]

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