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Date: Tue, 5 Dec 2000 15:17:07 -0500 (EST)
From: Alexander Viro <viro@math.psu.edu>
To: Linus Torvalds <torvalds@transmeta.com>
cc: "Stephen C. Tweedie" <sct@redhat.com>,
        Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Alexander Viro <aviro@redhat.com>, Andrew Morton <andrewm@uow.edu.au>,
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        Rik van Riel <riel@conectiva.com.br>,
        MOLNAR Ingo <mingo@chiara.elte.hu>
Subject: Re: test12-pre5
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On Tue, 5 Dec 2000, Linus Torvalds wrote:

> And this is not just a "it happens to be like this" kind of thing. It
> _has_ to be like this, because every time we call clear_inode() we are
> going to physically free the memory associated with the inode very soon
> afterwards. Which means that _any_ use of the inode had better be long
> gone. Dirty buffers included.

Urgh. Linus, AFAICS we _all_ agree on that. The only real question is
whether we consider calling clear_inode() with droppable dirty buffers
to be OK. It can't happen on the dispose_list() path and I'ld rather
see it _not_ happening on the delete_inode() one. It's a policy question,
not the correctness one.

IOW, I would prefer to have BUG() instead of invalidate_inode_buffers()
and let the ->delete_inode() make sure that list is empty. I'm not saying
that current code doesn't work. However, "let's clean after the
truncate_inode_page()/foo_delete_inode(), they might leave some junk
on the list" looks like a wrong thing.

Notice that policy wrt pages is already of that kind - clear_inode()
expects the callers to make sure that ->i_data.nr_pages is zero instead of
trying to clean after them. I think that we will be better off with
similar rules wrt dirty buffers list.

Comments?

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