Hi Jens,
Unless you have specific reason for not doing in __bio_clone(), I agree
with Neil's suggestion. Please consider the following patch:
--- linux-2.6.12-rc4-orig/fs/bio.c 2005-05-16 10:13:27.000000000 -0500
+++ linux-2.6.12-rc4-patch/fs/bio.c 2005-05-16 10:15:06.000000000 -0500
@@ -255,10 +255,7 @@
bio->bi_flags |= 1 << BIO_CLONED;
bio->bi_rw = bio_src->bi_rw;
- /*
- * notes -- maybe just leave bi_idx alone. assume identical mapping
- * for the clone
- */
+ bio->bi_idx = bio_src->bi_idx;
bio->bi_vcnt = bio_src->bi_vcnt;
bio->bi_size = bio_src->bi_size;
bio_phys_segments(q, bio);
--
Regards,
Mike T.
On Fri, 2005-05-13 at 18:08, Neil Brown wrote:
> On Friday May 13, mhtran@xxxxxxxxxx wrote:
> > Hi Neil et al,
> >
> > The scenario: Having LVM (striped) volumes on top of 2 raid1 devices
> > The problem: Corruption in building the scatter gather list for
> > device driver (see /drivers/block/blk_rq_map_sg() function)
> >
> > In DM code, a bio sometimes can be split into several
> > clones and the clones' bi_idx is set accordingly by DM. MD raid1 also
> > clones bio but does not adjust bi_idx. The problem can be fixed in
> > either __bio_clone() or the caller of bio_clone(). I chose to fix
> > raid1.
>
> Presumably the same fix would be needed in the "write" path and all in
> the read-retry path in raid1d?
>
> Why not just put it in __bio_clone, which would be one change instead
> of (atleast) 3?
>
> NeilBrown
>
> >
> > --- linux-2.6.12-rc4-orig/drivers/md/raid1.c 2005-05-10 13:35:06.000000000-0500
> > +++ linux-2.6.12-rc4-patch/drivers/md/raid1.c 2005-05-13 15:41:43.000000000-0500
> > @@ -577,6 +577,7 @@
> >
> > r1_bio->bios[rdisk] = read_bio;
> >
> > + read_bio->bi_idx = bio->bi_idx;
> > read_bio->bi_sector = r1_bio->sector + mirror->rdev->data_offset;
> > read_bio->bi_bdev = mirror->rdev->bdev;
> > read_bio->bi_end_io = raid1_end_read_request;
> >
> > --
> > Regards,
> > Mike T.
> >
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