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Re: [linux-lvm] LVM2 modifies the buffer_head struct?

Jens Axboe wrote:
> ...
> > We just want ext3/jbd to make sure that it only calls bh2jh on
> > an unlocked buffer... is that easy?
> That's the question indeed, someone with a good grasp of jbd should make
> that call. If that is the only 'violator' (depending on your point of
> view), then yes lets just fix that up and say that the above is pb
> private is valid.

We really don't want to do this, please.  Changing things so
that we can only run bh2jh() and, particularly, journal_add_journal_head()
on a locked buffer would involve fairly unpleasant surgery against
parts of ext3 which are already prone to exploding.  Like

If it was needed for 2.5 then hmm, maybe.  But as this is only a
2.4 problem then I really don't think we should risk breaking
or slowing down the filesystem for this.

Look, it's easy: delete buffer_head.b_inode (which is only used as 
a boolean), move its function to a b_state bit.  Add a new
buffer_head.ext3_hack and we can use that for pointing at the journal_head.

<insert "stable kernel" mantra here ;)>


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