We may wish to write language bindings for btrfs operations at some point. Python, for example. This will require the ioctl header file (btrfs-progs/ioctl.h or kernel/fs/btrfs/ioctl.h). Should this go in kernel-devel or a btrfs-progs-devel?
# rpm -q btrfs-progs-devel btrfs-progs-devel-0.20.rc1.20130917git194aa4a-1.fc21.x86_64 # rpm -ql btrfs-progs-devel | grep ioctl /usr/include/btrfs/ioctl.h Fixed in rawhide... (and f20 and f19 by when they get pushed)