HN user
As Russ points out in his earlier re2-related blog posts, these regex engines still perform non-linearly on inputs which don't involve look-around, look-behind, etc. There's plenty of room for improvement even if they want to keep these features.
Confirming that Fedora 16 is affected, with the latest updates as of the time of this writing.
No, they don't. Be wary. I tried to use btrfs in raid10 (data and metadata) mode for my latest array of large disks (4x 2TB WD Caviar Blacks); 70 GB in copying data from my old md array, I got a kernel OOPS. This was with very recent btrfs code -- Fedora 16 with a 3.1.x kernel and btrfs-progs-0.19-16.fc16. It's simply not ready.