Re: [PATCH] md: Partially revert 2f6db2a7, which broke raid5

[Jens Axboe <axboe@kernel.dk>]

On Thu, May 30 2013, NeilBrown wrote:
> On Wed, 29 May 2013 15:03:40 +0200 Jens Axboe <axboe@kernel.dk> wrote:
> 
> > On Wed, May 29 2013, Richard W.M. Jones wrote:
> > > 
> > > On Sun, May 19, 2013 at 10:51:45AM -0700, Kent Overstreet wrote:
> > > > Sorry for the delay - been vacationing. Reproduced the original bug,
> > > > here's a patch that fixes it:
> > > > 
> > > > 
> > > > commit 402f5db3708b2062795a384a3d8397cf702e27bc
> > > > Author: Kent Overstreet <koverstreet@google.com>
> > > > Date:   Sun May 19 10:27:07 2013 -0700
> > > > 
> > > >     raid5: Initialize bi_vcnt
> > > >     
> > > >     The patch that converted raid5 to use bio_reset() forgot to initialize
> > > >     bi_vcnt.
> > > >     
> > > >     Signed-off-by: Kent Overstreet <koverstreet@google.com>
> > > >     Cc: NeilBrown <neilb@suse.de>
> > > >     Cc: Jens Axboe <axboe@kernel.dk>
> > > >     Cc: linux-raid@vger.kernel.org
> > > > 
> > > > diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
> > > > index 9359828..753f318 100644
> > > > --- a/drivers/md/raid5.c
> > > > +++ b/drivers/md/raid5.c
> > > > @@ -664,6 +664,7 @@ static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
> > > >  			if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
> > > >  				bi->bi_rw |= REQ_FLUSH;
> > > >  
> > > > +			bi->bi_vcnt = 1;
> > > >  			bi->bi_io_vec[0].bv_len = STRIPE_SIZE;
> > > >  			bi->bi_io_vec[0].bv_offset = 0;
> > > >  			bi->bi_size = STRIPE_SIZE;
> > > > @@ -701,6 +702,7 @@ static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
> > > >  			else
> > > >  				rbi->bi_sector = (sh->sector
> > > >  						  + rrdev->data_offset);
> > > > +			rbi->bi_vcnt = 1;
> > > >  			rbi->bi_io_vec[0].bv_len = STRIPE_SIZE;
> > > >  			rbi->bi_io_vec[0].bv_offset = 0;
> > > >  			rbi->bi_size = STRIPE_SIZE;
> > > 
> > > Ditto to the previous follow up.  We've been tracking this
> > > bug for nearly a month:
> > > 
> > > https://bugzilla.redhat.com/show_bug.cgi?id=962079
> > > 
> > > Please include this (or the other) patch to fix it.
> > 
> > I'm assuming both Kent and I are waiting for Neil to pick it up. Neil, I
> > can include this in my next round going upstream, just let me know. It
> > should have been sent upstream a while back, sorry guys.
> > 
> 
> Seems you were waiting for me, and I was waiting for you :-)
> 
> Yes: please include it with your next round.  Thanks!

Hah, in that case we could have waited for a long time! I'll add it to
the current mix, thanks.

-- 
Jens Axboe