On Fri, Sep 14, 2012 at 09:01:36PM +0800, Liu Bo wrote:

Fine, please run xfstests 068 till it hits a BUG_ON inside either btrfs_delete_delayed_dir_index or
btrfs_insert_delayed_dir_index.

068 is the freezer test, we've seen enough issues in the freezing area
recently, I'm curious if you were able to reproduce with a non-freezing
tests.

It's quite possible that this may be a race condition and the freezer
just supplies the right delays and widens the race window.