Re: no space left on device

quoted

That patch is released on this list on january 26th, called "Fix
balance panic". If you experience the same, you could try applying
this patch too. There is no (pre-built) kernel yet with this patch
already applied.

Maybe it will help. But my actual problem is: I cannot mount the btrfs  
system (it leads to "kernel panic"). And starting "btrfs filesystem  
balance ..." requires a mounted btrfs system.

Yeah sorry, I hadn't noticed that. No, that patch will certainly not fix
a filesystem you can't mount to begin with. Can't help you out.

 - Erik