Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences

From: Jan Kara
Date: Tue Feb 02 2016 - 11:46:36 EST


On Tue 02-02-16 08:33:56, Dan Williams wrote:
> On Tue, Feb 2, 2016 at 3:17 AM, Jan Kara <jack@xxxxxxx> wrote:
> [..]
> > I see, thanks for explanation. So I'm OK with changing what is stored in
> > the radix tree to accommodate this use case but my reservation that we IHMO
> > have other more pressing things to fix remains...
>
> We don't need pfns in the radix to support XFS RT configurations.
> Just call get_blocks() again and use the sector, or am I missing
> something?

You are correct. But if you decide to pay the cost of additional
get_block() call, you only need the dirty tag in the radix tree and nothing
else. So my understanding was that the whole point of games with radix tree
is avoiding this extra get_block() calls for fsync().

Honza
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR