Re: strange ext3 corruption problem on 2.6.x

[Marc Singer <elf@buici.com>]

On Fri, Mar 12, 2004 at 06:34:23PM -0800, Andrew Morton wrote:
> Marc Lehmann <pcg@schmorp.de> wrote:
> >
> >  I use lvm-over-raid5 and get these messages once a day (requiring a reboot
> >  afterwards):
> > 
> >     EXT3-fs error (device dm-0): ext3_readdir: bad entry in directory #4804801: directory entry across blocks - offset=0, inode=0, rec_len=50000,
> >     name_len=152
> >     Aborting journal on device dm-0.
> 
> (and fsck comes up clean)
> 
> There have been earlier reports of this.  Too many for it to be some random
> glitch.   We've had similar reports in 2.4, usually with raid5.
> 
> I'm fairly confident in ext3 - it's hard to think of an ext3-level bug
> which wouldn't have 10x as many reports from non-md users.  But perhaps
> some timing unique to the MD layer is triggering some ext3 bug.
> 
> Joe, Neil: have you spotted reports like this?  Any suggestions as to how
> to track it down a bit?

I, too, have been experiencing this with ext3 on top of lvm on top of
raid5.  I also have a dual-proc machine.

It seems to be some sort of race condition because it is triggered by
multiple disk-io intensive processes using the same volume.  Many
mornings, when I first login to this machine which runs all of the
time, I find that one or more of the volumes is mounted read-only.
Sometimes e2fsck shows errors and sometimes it doesn't.