> From: Mark Hahn [mailto:[EMAIL PROTECTED]
>
> > In its current implementation write-back mode acknowledges writes
before
> > they have reached non-volatile media.
>
> which is basically normal for unix, no?
I am referring to when bi_end_io is called on the bio submitted to MD.
Normally it is not called until after the bi_end_io event for the bio
submitted to the backing disk.
>
> are you planning to support barriers? (which are the block system's
way
> of supporting filesystem atomicity).
Not as a part of these performance experiments. But, I have wondered
what the underlying issues are behind raid5 not supporting barriers.
Currently in raid5.c:make_request:
if (unlikely(bio_barrier(bi))) {
bio_endio(bi, bi->bi_size, -EOPNOTSUPP);
return 0;
}
--
Dan
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