Re: [git pull] vfs pile 3

[Al Viro <viro@ZenIV.linux.org.uk>]

On Sat, Oct 13, 2012 at 11:48:10AM -0400, Christoph Hellwig wrote:
> On Sat, Oct 13, 2012 at 08:51:28AM +0100, Al Viro wrote:
> > It's somewhat pointless on its own...  If you were doing something with
> > the callers afterwards - sure, it would be make sense, but as it is...
> 
> I'd really like to see ->truncate and vmtruncate done, so from that side
> I'm absolutely in favour of this series.  What I'm a bit concerned about
> is that it just does the trivial 1:1 conversion and not actually
> converts the sequence of operations to the proper form, which was one
> of the two big reasons of moving away from ->truncate to start with.
> 
> I'd love to see the full conversion, but without adequate test coverage
> for all the fringe filesystems that might be a bit too much to expect
> from Marco.
> 
> I think just doing the easy conversions he did, and putting a TODO
> comment explaining how it should be taken further at each of the sites
> would be valueable on its own.

You know, I'm in the middle of dealing with one such TODO.  Yours, as it
were.  From six years ago.  kernel_thread() unexporting.  TODO comments
of any form are routinely shat upon and ignored, especially when shuffled
away into less read parts of the tree... ;-/

I'd rather see it done fs-by-fs.  Starting with something reasonably easy
to test - minixfs would do nicely.  Don't get me wrong - I'm all for
burying ->truncate(); what I'm worried about is that we'll end up burying
the warning about the reasons why vmtruncate() was a bad idea, leaving the
functionality exactly as it used to be...