Re: RFC: iomap write invalidation

Christoph Hellwig
2020-07-21T15:42:44Z

On Tue, Jul 21, 2020 at 04:31:36PM +0100, Matthew Wilcox wrote:
> > Umm, no. -ENOTBLK is internal - the file systems will retry using
> > buffered I/O and the error shall never escape to userspace (or even the
> > VFS for that matter).
>
> Ah, I made the mistake of believing the comments that I could see in
> your patch instead of reading the code.
>
> Can I suggest deleting this comment:
>
> /*
> * No fallback to buffered IO on errors for XFS, direct IO will either
> * complete fully or fail.
> */
>
> and rewording this one:
>
> /*
> * Allow a directio write to fall back to a buffered
> * write *only* in the case that we're doing a reflink
> * CoW. In all other directio scenarios we do not
> * allow an operation to fall back to buffered mode.
> */
>
> as part of your revised patchset?

That isn't actually true. In current mainline we only fallback on
reflink RMW cases, but with this series we also fall back for
invalidation failures.