Re: [BUG] raid1: barrier retry does not work correctly with write-behind

[Paul Clements <paul.clements@steeleye.com>]

Neil Brown wrote:

> sector, bdev, size are all remembered in r1_bio.
> That leaves bi_idx and an array od len/offset pairs that we need
> to preserve.
> 
> So I guess the first step is to change alloc_behind_pages to
> return a new 'struct bio_vec' array rather than just a list of pages,
> and we should keep that array attached to the raid1_bio.

I think bio_clone gives us that already. I may have missed something but 
I think we have everything we need:

When a bio comes into raid1's make_request we bio_clone for each drive 
and attach those to r1_bio->bios. We also have behind_pages, which 
contains the pages. I think maybe instead of cloning r1_bio->master_bio, 
we can just clone r1_bio->bios[i]. Does that make sense?

Let me try that.

--
Paul