Comment # 10 on bug 1017461 from Richard Weinberger

(In reply to Goldwyn Rodrigues from comment #9)
> I have been trying to recreate this issue (especially the trace in comment
> #3) but have not succeeded so far.

Well, I don't expect this to be reproducible within a few minutes.
It happened here in my build server after an uptime of more than two weeks. 

> Richard: Does btrfs check report your filesystem is healthy?

The check upon boot reports it as healthy.
Since it is my rootfs I cannot run the check directly.

> Ronan: Are you getting these backtraces in the kernel log as well?
> 
> btrfs balance is a relatively I/O intensive operation because it has to move
> around chunks. However, if the tree is balanced frequently, then each
> balance should not take as much time.

The reporter here seem to observe the opposite. ;-)