Re: [RFC PATCH v2 5/5] mm: Remove swap BIO paths and only use DIO paths [BROKEN]

From: Christoph Hellwig
Date: Fri Aug 13 2021 - 03:14:22 EST


On Thu, Aug 12, 2021 at 09:22:41PM +0100, David Howells wrote:
> [!] NOTE: This doesn't work and might damage your disk's contents.
>
> Delete the BIO-generating swap read/write paths and always use
> ->direct_IO(). This puts the mapping layer in the filesystem.
>
> This doesn't work - probably due to ki_pos being set to
> page_file_offset(page) which then gets remapped.

Also because most common block file systems do not actually implement
a ->direct_IO that does anything (noop_direct_IO).