Re: [PATCH 2/2] iomap: fall back to buffered writes for invalidation failures

Christoph Hellwig
2020-07-14T11:00:18Z

On Mon, Jul 13, 2020 at 12:55:09PM +0100, Matthew Wilcox wrote:
> On Mon, Jul 13, 2020 at 09:46:33AM +0200, Christoph Hellwig wrote:
> > Failing to invalid the page cache means data in incoherent, which is
> > a very bad state for the system. Always fall back to buffered I/O
> > through the page cache if we can't invalidate mappings.
>
> Is that the right approach though? I don't have a full picture in my head,
> but wouldn't we be better off marking these pages as !Uptodate and doing
> the direct I/O?

Isn't that a problem if e.g. pages are mapped into userspace and mlocked?