Re: [PATCH v3 5/6] netfs, 9p, afs, ceph: Use folios

David Howells
2021-11-03T14:58:49Z

Matthew Wilcox <willy@infradead.org> wrote:

> > + len = (size >= start + gran) ? gran : size - start;
>
> This seems like the most complicated way to write this ... how about:
>
> size_t len = min_t(loff_t, isize - start, folio_size(folio));

I was trying to hedge against isize-start going negative. Can this code race
against truncate? truncate_setsize() changes i_size *before* invalidating the
pages.

> > static int afs_symlink_readpage(struct file *file, struct page *page)
> > {
> > - struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
> > + struct afs_vnode *vnode = AFS_FS_I(page_mapping(page)->host);
>
> How does swap end up calling readpage on a symlink?

Um - readpage is called to read the symlink.

> > - page_endio(page, false, ret);
> > + page_endio(&folio->page, false, ret);
>
> We need a folio_endio() ...

I think we mentioned this before and I think you said you had or would make a
patch for it. I can just create a wrapper for it if that'll do.

David