From mboxrd@z Thu Jan 1 00:00:00 1970 From: Zachary Palmer Subject: Re: Linux 3.11-rc4 Writeback Cache Corruption Date: Wed, 04 Sep 2013 23:16:04 -0400 Message-ID: <5227F774.7010002@bahj.com> References: <52265410.4010000@bahj.com> <522656EC.8040002@gmail.com> <5227F74F.5000305@bahj.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <5227F74F.5000305-J5qI5MFTcs8@public.gmane.org> Sender: linux-bcache-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: linux-bcache-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-bcache@vger.kernel.org Whoops; forgot to send this e-mail to the whole list. :) > So I have some unfortunate test results regarding this corruption > issue. I tested my laptop on two kernels I built today. The > procedure was as follows: > > 1. Check out bcache-3.10-stable. Kernal was build using the > .config I have for Debian package > linux-image-3.10-0.bpo.2-686-pae=3.10.5-1~bpo70+1. All new options > were left at defaults. > 2. Begin by checking out bcache git repository at > bcache-for-3.11. Next, add Linux stable git as an origin. Then, "git > br temp; git co temp; git merge linux-3.11.y". The merge applies > automatically. Build the resulting kernel, again using the above > .config with all new options left at defaults. > > My hope was that one of these two kernels would resolve both (a) the > cache corruption issue and (b) my hibernate/suspend problem. This did > not appear to be the case. Using kernel #2 above (Linux 3.11.0), > cache corruption was immediately evident; both apt-cacher and MySQL > failed to start due to segfaults. Cache corruption was resolved by > detaching and reattaching the cache device under a clean kernel. > > Using kernel #1 above, I get the same results as the Debian stock > kernel for Wheezy backports (the one from the package named above): > bcache seems to work just fine until the kernel attempts to stop > devices for suspend, hibernate, or shutdown; at this point, bcache > times out waiting for the device to stop and the laptop never changes > power states. > > For the time being, it is easier for me to live without > suspend/hibernate than it is for me to migrate back to a cacheless > layout; moving all of that data around is time-consuming and I really > want to use bcache. :) If there is any information I could collect > with my machine that would help in the debugging process, please let > me know! > > Thanks, > > Zach >> [This mail was also posted to gmane.linux.kernel.bcache.devel.] >> >> On Tue, 03 Sep 2013 17:26:40 -0400, Zachary Palmer wrote: >>> So here's the question: how would I best go about testing this patch? >>> In looking through the git history, it doesn't seem as if the >>> bcache-for-3.11 branch has been synced against the Linux git since >>> 3.10-rc7 (on June 22nd). I was thinking I could >>> >>> * Pull the Linux kernel source >>> * Add the bcache git as an origin >>> * Merge the bcache-for-3.11 branch into the Linux 3.11 mainline >>> branch myself and >>> * Assuming that this works, compile and boot the resulting kernel >>> using my Debian kernel .config >>> >>> Does this sound reasonable? Or is there a better way to do this? I'm >>> pretty happy with whatever gives me at least the behavior of my >>> mainline >>> 3.10 kernel and I'm looking forward to getting bcache and laptop power >>> modes on the same machine. :) >> Yeah, it'll merge cleanly. You can reuse the .config and build with >> `make deb-pkg -j -l6`, which is slowly replacing make-kpkg >> functionality. >> >> >