Re: [PATCH v2 2/9] ext2: tell DAX the size of allocation holes

From: Theodore Ts'o
Date: Mon Aug 29 2016 - 08:57:59 EST

On Mon, Aug 29, 2016 at 12:41:16AM -0700, Christoph Hellwig wrote:
> We're going to move forward killing buffer_heads in XFS. I think ext4
> would dramatically benefit from this a well, as would ext2 (although I
> think all that DAX work in ext2 is a horrible idea to start with).

It's been on my todo list. The only reason why I haven't done it yet
is because I knew you were working on a solution, and I didn't want to
do things one way for buffered I/O, and a different way for Direct
I/O, and disentangling the DIO code and the different assumptions of
how different file systems interact with the DIO code is a *mess*.

It may have gotten better more recently, but a few years ago I took a
look at it and backed slowly away.....

- Ted