Re: put the xfs xfile abstraction on a diet v2

[Christoph Hellwig <hch@lst.de>]

On Fri, Jan 26, 2024 at 02:15:44PM +0000, Matthew Wilcox wrote:
> hwpoison is per page not per file.  That's intrinsic to, well, hardware
> poison, it affects an entire page (I'd love to support sub-page poison,
> but not enough to spend my time working on memory-poison.c).
> 
> In general, I think there's a lack of understanding of hwpoison, and
> I include myself in that.  Mostly I blame Intel for this; limiting the
> hardware support to the higher end machines means that most of us just
> don't care about it.
> 
> Why even bother checking for hwpoison in xfiles?  If you have flaky
> hardware, well, maybe there's a reason you're having to fsck, and crashing
> during a fsck might encourage the user to replace their hardware with
> stuff that works.

But the sentence is stale actually - we're using folios now after Darrick
coded up a helper check all the hwpoison cases and others.  I should
have removed it from the commit log.  Crashing is never a good idea
I think if we can easily avoid it.

Note that I still find the difference in hwpoison checking in shmem
vs filemap rather confusing.