Fwd: [BUG] reiser4-for-2.6.22-2 Large stalls when using atime mount option

["Dushan Tcholich" <dusanc@gmail.com>]

---------- Forwarded message ----------
From: Dushan Tcholich <dusanc@gmail.com>
Date: Nov 9, 2007 3:03 PM
Subject: Re: [BUG] reiser4-for-2.6.22-2 Large stalls when using atime
mount option
To: Edward Shishkin <edward.shishkin@gmail.com>


There were some stalls, but a lot shorter than before (~7sec on
shutdown with patch, ~3.5min without), and no kernel messages.
Stalls that were encountered during normal use were short 1-3sec.
Take all this with a grain of salt because, for me, these are hard to reproduce.
kernel2.6.22-r8+reiser-for-2.6.22-2.patch+reiser4-discard-entd.patch
reiser4 mounted as / without -noatime option.

Dusan




On Nov 9, 2007 2:04 AM, Edward Shishkin <edward.shishkin@gmail.com> wrote:
> Hello guys.
> This is the promised patch against (2.6.22 + reiser4-for-2.6.22-2).
>
> Note, that this patch may cause problems, so keep also a stable kernel
> to boot on.
> The goal is to detect any progress in preventing the nasty stalls:
> please boot to the
> patched kernel and try to reproduce them. If you encounter oops, then
> reboot to the
> same kernel and try again. If oopses are annoying, then boot to the
> stable kernel and
> let me know about it.
>
> Waiting for your results..
> Thanks,
> Edward.
>
>
> On 11/8/07, Dushan Tcholich <dusanc@gmail.com> wrote:
> > Hi
> >
> > On Nov 7, 2007 10:31 PM, Edward Shishkin <edward.shishkin@gmail.com> wrote:
> > > Hello.
> > >
> > > On 11/7/07, Dushan Tcholich <dusanc@gmail.com> wrote:
> > > > Kernel: Gentoo 2.6.22-r2 + reiser4-for-2.6.22-2.patch
> > > > fstab:
> > > > /dev/sda2        /boot        ext2        noauto,noatime    1 2
> > > > /dev/sda5        /        reiser4                0 0
> > > > /dev/sda3        none        swap        sw        0 0
> > > > /dev/sda6        /home        ext3        noatime        0 0
> > > >
> > > > reiser4 partition is with cryptocompress (lzo) default settings.
> > > >
> > > > I usually mount r4 with -noatime, but after some debbuging with some users
> > > > on irc (rvalles), who have intermitent large stalls, we found that only
> > > > difference between our setups was my -noatime flag in fstab.
> > >
> > > Plus rvalles doesn't use compression (isn't it?)
> >
> > He had stalls without compression, but now switched to compression and
> > still has them.
> > But I can't reproduce them with -noatime option.
> > >
> > > > I tried to mount / without -noatime, started gnome, and then in about same
> > > > time evolution, firefox, played some mp3s, avis, did a kernel compile,
> > > > emerge -uD world (compiled few packages), acessed some random fles in
> > > > /usr/src/linux, started gnome disk usage analyser etc. and had no stalls at
> > > > all.
> > > > And then I tried to reboot. System stalled for 3min 25 sec (i was ready with
> > > > a watch :)) before printing the first message, with heavy disk activity.
> > > > Upon reboot I just changed line in fstab with nano to mount r4 with -noatime
> > > > and rebooted agin. Now there were no stalls.
> > > >
> >
> > To my inexperienced eyes it looks like lazy writes of atime are adding
> > with that "reiser4 writes continuously to same sector" bug.
> >
> > >
> > > Currently I am preparing a patch for this problem.
> > > Not sure about its efficiency: we'll take a look..
> >
> > Great
> >
> > >
> > > Thanks,
> > > Edward.
> > >
> >
> > Dushan
> >
>