Re: [RFC v2 02/11] fs/buffer: add a for_each_bh() for block_read_full_folio()

Luis Chamberlain
2024-12-16T20:05:58Z

On Mon, Dec 16, 2024 at 10:56:44AM -0800, Luis Chamberlain wrote:
> On Sat, Dec 14, 2024 at 04:02:53AM +0000, Matthew Wilcox wrote:
> > On Fri, Dec 13, 2024 at 07:10:40PM -0800, Luis Chamberlain wrote:
> > > - do {
> > > + for_each_bh(bh, head) {
> > > if (buffer_uptodate(bh))
> > > continue;
> > >
> > > @@ -2454,7 +2464,9 @@ int block_read_full_folio(struct folio *folio, get_block_t *get_block)
> > > continue;
> > > }
> > > arr[nr++] = bh;
> > > - } while (i++, iblock++, (bh = bh->b_this_page) != head);
> > > + i++;
> > > + iblock++;
> > > + }
> >
> > This is non-equivalent. That 'continue' you can see would increment i
> > and iblock. Now it doesn't.
>
> Thanks, not sure how I missed that! With that fix in place I ran a full
> baseline against ext4 and all XFS profiles.
>
> For ext4 the new failures I see are just:
>
> * generic/044
> * generic/045
> * generic/046

Oh my, these all fail on vanilla v6.12-rc2 so its not the code which is
at fault.

Luis