Re: [PATCHSET RFC v2 jane 0/5] vfs: enable userspace to reset damaged file storage

Dan Williams
2021-09-23T01:17:49Z

On Wed, Sep 22, 2021 at 5:52 PM Darrick J. Wong <djwong@kernel.org> wrote:
>
> I withdraw the patchset due to spiralling complexity and the need to get
> back to the other hojillion things.
>
> Dave now suggests creating a RWF_CLEAR_POISON/IOCB_CLEAR_POISON flag to
> clear poison ahead of userspace using a regular write to reset the
> storage. Honestly I only though of zero writes because I though that
> would lead to the least amount of back and forth, which was clearly
> wrong.
>

Sorry Darrick, you really tried to do right by the feedback.

> Jane, could you take over and try that?

Let's just solve the immediate problem for DAX in the easiest way
possible which is just Jane's original patches, but using the existing
dax_zero_page_range() operation in the DAX pwrite() failure path. The
only change would be to make sure that the pwrite() is page aligned,
and punt on the ability to clear poison on sub-page granularity for
now.