Re: r4 observations

["Peter" <sw98234-PkbjNfxxIARBDgjK7y7TUQ@public.gmane.org>]

On Fri, 22 Sep 2006 14:02:44 +0200, Thomas Kuther wrote:

> On Thu, 21 Sep 2006 11:18:41 +0000 (UTC)
> "Peter" <sw98234-PkbjNfxxIARBDgjK7y7TUQ@public.gmane.org> wrote:
> 
>> On Thu, 21 Sep 2006 15:02:01 +0400, Vladimir V. Saveliev wrote:
>> 
>> > Hello
>> > 
>> > On Wednesday 20 September 2006 22:47, Peter wrote:
>> >> I booted from a non-reiser4 partition in order to make a backup of
>> >> my main / which was a r4 partition.
>> >> 
>> >> After the backup, I unmounted the drive explicitly, then rebooted.
>> >> 
>> >> I did not use the backed up drive for anything except tar-ring its
>> >> files.
>> >> 
>> >> On next boot to the r4 / partition, all kinds of file not found
>> >> errors occurred. I booted again to my non-r4 partition, and ran
>> >> fsck.reiser4 --check -y there were fatal errors on my r4 /.
>> >> 
>> >> The backup was fine. I downgraded back to reiserfs which does not
>> >> exhibit this problem.
>> >> 
>> >> I have not experienced any problem with other r4 partitions.
>> >> Just /. /home, /tmp, /src, etc. are fine.
>> >> 
>> >> Unfortunately, I don't have time to keep wondering where the
>> >> problem is or why. Perhaps it's the kernel or the init scripts.
>> >> Nonetheless, the instability of whatever the problem is is
>> >> unnerving.
>> >> 
>> > 
>> > Please provide information about which kernel and which reiser4 did
>> > you use. Am I correct that you were trying to run gentoo on reiser4?
>> 
>> Yes, Vladimir. When making the backup, I was not running Gentoo at
>> all. I was running Slackware 10.2. I booted into Slackware with the
>> beyond patchset (ck superset) based on 2.6.17.11 with the reiser4
>> 2.6.17-3 patch. All of the work on backup mount and unmount was on
>> Slackware. It was when rebooting back into Gentoo (with the init and
>> base layout which DID NOT CAUSE a boot problem) that the fatal errors
>> occurred. Interestingly, and maybe this is helpful, only the /
>> partition seems to be affected. I have observed no problematic
>> behavior with any of the other three partitions I used r4 for. In
>> fact, even though I downgraded / to reiserfs3, the other r4
>> partitions work fine. Please let me know if I can provide additional
>> information.
>> 
> 
> 2.6.17-beyond includes -ck1 which includes fcache which is totally evil
> for reiser4. The old fscache patch in .17-ck1 tends to kill reiser4 /usr
> here (I assume your /usr is in / then) when rebooting/umounting the
> partition. Also newer -mm is evil and umount on /usr completely fails
> here, i have to hard reset the box, but here the partitions stay
> alive, with the older fcache i had to --build-sb and --fix it, and
> then remerge all stuff that was lost.
> Oh and this happens even i didn't enable fcache in kernel config, just
> the existance of the patch is enough.
> Strangely it's reproducably and only /usr. So if you run the /usr
> folder on a reiser4 partition, do NOT use -mm, or at least good luck
> trying to break out fcache. Reversing the fcache patch from -beyond is
> easy, just get the broken-out from -ck and patch -R it.
> 
> HTH
> Tom

Thanks for the tip, Tom! You're the second person (unless you're the same
one on the gentoo forums) to mention this. I suspect, with your use of the
word evil, you're the same! :)

Nonetheless, I lost patience, and did not want to be in a changing beta
situation as kernels, patches, etc. are all changing at different rates of
speed. I found this bug both annoying and disconcerting. I have one r4
partition left, and since it's not / there appear to be no problems.

I assume the various parties involved are all aware of this?


-- 
Peter
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