Re: Crashes in extent_io.c after "btrfs bad mapping eb" notice

Hi,

I have been trying to get some sysrq output, but I am only getting hard
hangs right now. So no reaction to sysrq-w.

Here is some sysrq-w output from around 15 minutes before the crash:
https://www.dropbox.com/s/386ifyoxh8eppia/sysrqw_2012-11-1.log
I don't know if this will be helpful.

Tobias

On Thu, 01 Nov 2012 12:57:00 +0100
Jan Schmidt [off-list ref] wrote:

On Thu, November 01, 2012 at 03:39 (+0100), Liu Bo wrote:

quoted

On 11/01/2012 04:00 AM, Franke wrote:

quoted

Hi,

since yesterday I have run a balance while asleep/at work. Now I
experimented a bit, and the situation has changed.

I am now getting hard hangs ( system is gone without even writing
anything to syslog ), some time ( minutes to an hour ) into
running a scrub.

Those hangs happen with 3.6.2 , 3.6.4 and Jan's unstable version.
It hasn't hung yet without running a scrub.

I have no idea if this is part of the same problem or something
else. Do you have any idea either way?

Well, thanks for testing.

We may need your sysrq-w output(maybe screen output) to locate
where we hard hangs.

Besides, I recommend you pick Jan's patches out, and apply them on
the latest btrfs upstream and run another round to see if it get
better, since there might be some fixes for the very hang already
in the upstream.

Right now the latest btrfs upstream's top commit is

commit f46dbe3dee853f8a860f889cb2b7ff4c624f2a7a
Author: Chris Mason [off-list ref]
Date:   Tue Oct 9 11:17:20 2012 -0400

    btrfs: init ref_index to zero in add_inode_ref
    
    Signed-off-by: Chris Mason [off-list ref]

This is an old top commit. The current cmason/master state is

commit c37b2b6269ee4637fb7cdb5da0d1e47215d57ce2
Author: Josef Bacik [off-list ref]
Date:   Mon Oct 22 15:51:44 2012 -0400

and includes my recent fixes. I don't really expect them to prevent
getting stuck anywhere. sysrq+w output would be really helpful. I'm
trying to reproduce the problems in the meantime.

-Jan