Re: [PATCH RFC 5/6] md/raid1: Handle bio_split() errors

[John Garry]

On 24/10/2024 10:12, Yu Kuai wrote:
> > > > > > Indeed, IMO, chance of encountering a device with BBs and supporting
> > > > > > atomic writes is low, so no need to try to make it work (if it were
> > > > > > possible) - I think that we just report EIO.
> > >
> > > If you want this, then make sure raid will set fail fast together with
> > > atomic write. This way disk will just faulty with IO error instead of
> > > marking with BB, hence make sure there are no BBs.
> >
> > To be clear, you mean to set the r1/r10 bio failfast flag, right? 
> > There are rdev and also r1/r10 bio failfast flags.
>
> I mean the rdev flag, all underlying disks should set FailFast, so that
> no BB will be present. rdev will just become faulty for the case IO
> error.
>
> r1/r10 bio failfast flags is for internal usage to handle IO error.

I am not familiar with all consequences of FailFast for an rdev, but it 
seems a bit drastic to set it just because the rdev supports atomic 
writes. If we support atomic writes, then not all writes will 
necessarily be atomic.

Thanks,
John