With reboot, you mean abruptly unplug the power and insert it again?
Yes, this is handled by the Linux kernel, which buffers writes for some time. By buffering writes, wear on the flash is reduced, which has a limited number of write / erase cycles.
Using the data store module, data is safe however since fsync is used. A journal is also used for pending writes. We believe the data consistency of such data is important to be tolerant from power outages.
