Re: about ll_rw_blk.c of void generic_make_request(struct bio *bio)

[Chris Caputo <ccaputo@alt.net>]

On Fri, 31 Mar 2006, Jens Axboe wrote:
> On Fri, Mar 31 2006, Chris Caputo wrote:
> > On Fri, 31 Mar 2006, Chris Caputo wrote:
> > > On Thu, 30 Mar 2006, Jens Axboe wrote:
> > > > I can't really say, from my recollection of leafing over lkml emails, I
> > > > seem to recall someone saying he hit this with a newer kernel where as
> > > > the older one did not?
> > > > 
> > > > What are the sectors exactly it complains about, eg the full line you
> > > > see?
> > > 
> > > I see:
> > > 
> > >   attempt to access beyond end of device
> > >   sdb1: rw=0, want=134744080, limit=128002016
> > 
> > I believe the "rw=0" means that was a simple read request, and not a 
> > read-ahead.
> 
> Correct.
> 
> > 128002016 equals about 62 gigs, which is the correct volume size:
> > 
> >   Filesystem           1K-blocks      Used Available Use% Mounted on
> >   /dev/sdb1             62995364   2832696  56962620   5% /xxx
> > 
> >   /dev/sdb1 on /xxx type ext2 (rw,noatime)
> 
> How are you reproducing this, through the file system (reading files),
> or reading the device? If the former, is the file system definitely
> sound - eg does it pass fsck?

Filesystem level interaction via bonnie++.  Basic repro is, using ccaputo 
user, is:

  mke2fs -j -L /xxx /dev/sdb1
  mount -t ext2 /dev/sdb1 /xxx
  cd /xxx ; mkdir ccaputo ; chown ccaputo ccaputo ; cd ccaputo ; su ccaputo
  /usr/sbin/bonnie++

Filesystem is believed to be sound since it is from a fresh mke2fs.

The one strange thing I do is that I format it as ext3 (-j) but mount it 
as ext2, but I didn't think that would be an issue and I'd be surprised if 
Erich is doing the same in his tests, which also fail, with ext2.  (I do 
it in case I later decide to mount the volume as ext3.)

Chris
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