Re: btrfs lockup after mounting for a second time on 2.6.26

[Chris Mason <chris.mason@oracle.com>]

On Thu, 2009-02-12 at 01:31 -0500, Lee Trager wrote:
> While running a few tests with the btrfs sources pulled from
> btrfs-unstable patched with my patch to compile under 2.6.26 I
> encountered a very weird problem. Everything works fine the first time I
> mount the file system (either actual disk or loop back). When I
> unmounted the file system and mounted it again(I'm not doing mount -o
> remount ...) btrfs is completely unusable. When I tried to view some of
> the data which I previously put on the btrfs partition by doing a simple
> ls /mnt/btrfs in bash nothing happens. ls shows nothing, just hangs, and
> I am unable to kill ls. The same thing happens when I try to copy a file
> from my ext3 partition onto the btrfs partition after mounting it for a
> second time. The rest of the system is completely usable and the only
> things that are effects are applications which are trying to read/write
> from the btrfs file system. There are no kernel opps or any other errors
> messages in any of my logs. This happens if I have compression on or
> not. I'd be happy to fix this issue but I don't have a clue about where
> to start looking for what is wrong.
> 
> Could someone please help me?

Thanks for working on this.  The first step is to figure out what ls is
doing, and my guess is trying to read block groups.  Do a sysrq-w while
it is hung and send the results along.

-chris