Client library: design and implement plugable erasure coding interface: ECMethod to facilitate use of different erasure codes with QFS. Create QCRSMethod for original Quantqast RS encoding. Create jerasure stub, and define jerasure method id. Move relevant stripe parameters validation into the erasure code methods.
Meta server: make stripe parameters validation more flexible, do not assume qcrs striping.
Chunk server: change recovery parameters validation to be flexible, by not assuming qcrs recovery.