Re: [RFC][PATCH v2 0/5] Experiments with overlayfs filemap

Miklos Szeredi
2019-01-29T07:17:02Z

On Mon, Jan 28, 2019 at 11:14 PM Amir Goldstein <amir73il@gmail.com> wrote:
>
> On Mon, Jan 28, 2019 at 11:22 PM Miklos Szeredi <miklos@szeredi.hu> wrote:
> >
> > On Mon, Jan 28, 2019 at 10:17 PM Miklos Szeredi <miklos@szeredi.hu> wrote:
> >
> > > Trying to put some code together...
> >
> > Very rudimentary patch attached. It doens't do direct IO yet, but
> > demonstrates what I meant about achoring the upper file in the inode.
> >
>
> Code looks good, but blows up on xfstests, so I'll wait for a baked patch
> before testing.
>
> > Also found the trick to actually make writeback work:
> > super_setup_bdi() call in fill_super...
> >
>
> Cool, but when adding only setup_bdi() this to my code, I still don't see any
> writeback. No writeback observed with your patch as well.

I did observe writeback, but haven't done much testing. Will
hopefully get this into a better shape today.

> Speaking of which, did you read the warning sign above
> simple_write_end()? Aren't you missing the mark_inode_dirty() call?

That's in __set_page_dirty_nobuffers().

Thanks,
Miklos