Re: Lockups with loop'ed sparse files on reiserfs?

From: Oleg Drokin (
Date: Fri Jun 13 2003 - 15:22:05 EST


On Fri, Jun 13, 2003 at 08:07:55PM +0200, Christian Jaeger wrote:

> >Any chance to hit say sysrq-T/sysrq-P to find out where CPU spins?
> I've never used those, I'll have to learn about those debugging
> options first. Where should I go to?

Read /usr/src/linux/Documentation/sysrq.txt

> Now the question is wbat happens if a partition is full.

There were a known problem with reiserfs that it might sometimes
deadlock in out-of-space situation.
This is fixed in 2.4.21

> In fact I've seen this in kern.log (full log at
> ):
> Jun 13 11:34:57 pflanze kernel: raid5: md0, not all disks are
> operational -- trying to recover array
> ...
> Jun 13 11:34:57 pflanze kernel: md0: resyncing spare disk [dev 07:07]
> to replace failed disk

This is raid5 stuff resyncing. Probably it is normal if you just
setup the raid5 array.

> What does happen if a raid array fails (i.e. 2 disks fail and there's
> no spare, or 1 spare and 3 disks fail etc.)? If it's not an important

Everything that will access this array will break, I presume ;)

> array (i.e. no swap or root filesystem on it), is there a reason for
> the system to go down? Isn't it possible to just mark the mounted
> filesystem as erroneous and return EIO to applications accessing it?

Something like that will happen.

> There's also the case 1, using uml. In this case I'm sure there was
> no problem with space. The sparse filesystem image file I used is
> exactly 500'000'000 bytes, and there's 1675228 k free space on the
> partition where it is put on.

Ok, that's where sysrq-T/sysrq-P traceswould be most useful.
And if you'd try with 2.4.21 that would be even better.

Thank you.

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