Re: volume broken? btrfsck fails

[Thomas Kuther <gimpel@sonnenkinder.org>]

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On Mi, 04.08.10 21:30 Chris Mason <chris.mason@oracle.com> wrote:

> On Wed, Aug 04, 2010 at 08:48:40PM +0200, Thomas Kuther wrote:
> > On Di, 06.07.10 20:16 Chris Mason <chris.mason@oracle.com> wrote:
> > 
> > > On Sat, Jun 26, 2010 at 03:15:04PM -0700, Yee-Ting Li wrote:
> > > > Hi,
> > > > 
> > > > i think my btrfs volume is hosed.... it mounts okay, but iostat
> > > > shows /dev/sdg on 100% load. dmesg shows lots of 'parent transid
> > > > verify failed on x wanted y found z'. then after a while i can't
> > > > read from it (access to the filesystem freezes).
> > > > 
> > > > the machine had crashed (prob from some other process), and upon
> > > > reboot i've been experience this problem since.
> > > > 
> > > > can anyone provide any guidance in how to proceed?
> > > 
> > > These are definitely corruptions, and they probably came from the
> > > crash. Can you tell me more about the crash? (Power failure, what
> > > is the storage underneath etc, what are the write cache
> > > settings).  We don't expect these kinds corruptions to happen.
> > > 
> > > Yan Zheng is making a lot of progress on btrfsck, but I don't
> > > think you'll want to be one of the first testers there.  I can
> > > definitely help copy things off if you're having trouble
> > > accessing the FS.
> > > 
> > > -chris
> > 
> > Hello Chris,
> > 
> > sorry if I'm hijacking this thread. I got a similar problem,
> > probably caused by a system crash due to faulty/badly timed memory
> > dimms. The system suddenly hardlocked during write activity.
> > 
> > - kernel is 2.6.35
> > - btrfs on top of a md raid5, which looks healthy. Desktop SATA
> > disks.
> > 
> > # cat /proc/mdstat|grep -A1 md0
> > md0 : active raid5 sdb1[0] sdd1[1] sdc1[2]
> >       2930271872 blocks level 5, 64k chunk, algorithm 2 [3/3] [UUU]
> > 
> > # btrfsck
> > usage: btrfsck dev
> > Btrfs v0.19-16-g075587c-dirty
> > 
> > # btrfsck /dev/md0
> > parent transid verify failed on 2419218964480 wanted 127839 found
> > 127260 parent transid verify failed on 2419218964480 wanted 127839
> > found 127260 parent transid verify failed on 2419218915328 wanted
> > 127839 found 127260 parent transid verify failed on 2419218915328
> > wanted 127839 found 127260 parent transid verify failed on
> > 2419214266368 wanted 127839 found 127837 parent transid verify
> > failed on 2419214266368 wanted 127839 found 127837 parent transid
> > verify failed on 2419214266368 wanted 127839 found 127837
> > Segmentation fault
> > 
> > Mount endlessly loops, like explained in this thread.
> > 
> > If there is a way, I would really like some aid copying the data
> > off. The backup is quite out of date, shame on me.
> 
> No problem, I'll get a test patch out in the morning.
> 
> -chris
> 

Hi Chris,

did you find the time to get that patch done meanwhile?
I'm willing to test.

Seems more people get this error after power outages, suspending or
similar.

Thanks in advance.

~Thomas

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