BTRFS in 2012?

If BTRFS is used by default on boxes, then file system snapshots
insturmented in RPM's (or URPMI's) state machines become possible.

(aside)
There's a closely related usage case in build systems based on
populating a chroot which then uses a depsolver to populate
the chroot based on BuildRequirements. In the build system
case, reverting to the original chroot snapshot is (perhaps:
a measurement is needed to say for sure) an efficient implementation
to return to the original image (yes I am making an assumption that
each chroot is also a mount point.)

Is BTRFS being considered in 2012? If not, then RPM/URPM
using snapshots is less important than otherwise.

73 de Jeff