Re: [GIT PULL] Core block IO bits for 2.6.39 - early Oops

Markus Trippelsdorf
2011-03-25T09:57:09Z

On 2011.03.25 at 09:44 +0100, Jens Axboe wrote:
> On 2011-03-25 09:37, Markus Trippelsdorf wrote:
> > On 2011.03.25 at 08:23 +0100, Jens Axboe wrote:
> >> On 2011-03-24 22:41, Markus Trippelsdorf wrote:
> >>> On 2011.03.24 at 22:01 +0100, Jens Axboe wrote:
> >>>> On 2011-03-24 21:06, Markus Trippelsdorf wrote:
> >>>>> On 2011.03.24 at 20:57 +0100, Jens Axboe wrote:
> >>>>>>
> >>>>>> OK, still a data point. What was the last -git kernel you used?
> >>>>>
> >>>>> This one was the last and gave me no problems:
> >>>>>
> >>>>> commit b81a618dcd3ea99de292dbe624f41ca68f464376
> >>>>> Merge: 2f284c8 a9712bc
> >>>>> Author: Linus Torvalds <torvalds@linux-foundation.org>
> >>>>> Date: Wed Mar 23 20:51:42 2011 -0700
> >>>>>
> >>>>> Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6
> >>>>
> >>>> Puzzling... Poking at straws here so far. Does this make any difference
> >>>> whatsoever?
> >>>
> >>> I will test your patch later.
> >>>
> >>> Git-bisect gave me this result thus far:
> >>>
> >>> 9026e521c0da0731eb31f9f9022dd00cc3cd8885 is bad
> >>> 82f04ab47e1d94d78503591a7460b2cad9601ede is good
> >>>
> >>> When I continue the bisection with 4345caba340f051e10847924fc078ae18ed6695c
> >>> the system will start normally, but it then silently corrupts my xfs
> >>> partitions. And on next (re)boot I get this (only fixable with
> >>> xfs_repair):
> >>>
> >> How confident are you in those bisection results? Not trying to put you
> >> on the spot, just wondering whether you tested and it's completely
> >> consistent, or whether it was a one-off.
> >
> > Just double checked and 82f04ab47e1d94d78503591a7460b2cad9601ede is also
> > bad. It just silently corrupts the file system (without a BUG) and I
> > didn't notice.
> > So back to square one.
> >
> > How can I tell git-bisect just to try the commits in the block merge and
> > not to take wild swings in history?
>
> Something like:
>
> $ git bisect start
> $ git bisect good 3dab04e6978e358ad2307bca563fabd6c5d2c58b
> $ git bisect bad 6c5103890057b1bb781b26b7aae38d33e4c517d8

Ok this time I've found the commit:

9b6096a65f99a89dfd8328c4e469e7b53b3ae04a is the first bad commit
commit 9b6096a65f99a89dfd8328c4e469e7b53b3ae04a
Author: Shaohua Li <shaohua.li@intel.com>
Date: Thu Mar 17 10:47:06 2011 +0100

mm: make generic_writepages() use plugging

This recovers a performance regression caused by the removal
of the per-device plugging.

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

Reverting it solves all problems here.

--
Markus