Comment # 7 on bug 906684 from Libor Pechacek

For the record, the kernel bug message corresponds to the below code in
fs/btrfs/extent_io.c, __do_readpage().

  2868                 if (IS_ERR_OR_NULL(em)) {
  2869                         SetPageError(page);
  2870                         if (!parent_locked)
  2871                                 unlock_extent(tree, cur, end);
  2872                         break;
  2873                 }
  2874                 extent_offset = cur - em->start;
=>2875                 BUG_ON(extent_map_end(em) <= cur);
  2876                 BUG_ON(end < cur);

I can also see that there are subtle changes in this function between openSUSE
13.2 and current upstream.  Frank, Nicholas, Roman, Christoph, Stephan does the
bug still trigger with newer openSUSE releases?

(In reply to Stefan Ziegler from comment #6)
> Long live ext4 and reiserfs. They never caused problems.

:) Reiser really wasn't my FS of choice in 2002.  How time flies!