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

From: Chris Caputo
Date: Fri Mar 31 2006 - 15:35:14 EST


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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