Re: RFC: iomap write invalidation

Darrick J. Wong
2020-07-21T16:06:10Z

On Tue, Jul 21, 2020 at 06:01:43PM +0200, Christoph Hellwig wrote:
> On Tue, Jul 21, 2020 at 08:59:25AM -0700, Darrick J. Wong wrote:
> > In the comment that precedes iomap_dio_rw() for the iomap version,
>
> maybe let's just do that..
>
> > ``direct_IO``
> > called by the generic read/write routines to perform direct_IO -
> > that is IO requests which bypass the page cache and transfer
> > data directly between the storage and the application's address
> > space. This function can return -ENOTBLK to signal that it is
> > necessary to fallback to buffered IO. Note that
> > blockdev_direct_IO and variants can also return -ENOTBLK.
>
> ->direct_IO is not used for iomap and various other implementations.
> In fact it is a horrible hack that I've been trying to get rid of
> for a while.

Agreed, but for now there are still a number of fses who are still on
the old directio code; let's try to keep the drainbamage/confusion
potential to a minimum so it doesn't spread to our iomap shinyness. :)

--D