Budget Fair Queueing (BFQ) Storage-I/O Scheduler

Known bugs

All versions below v3r4 contain the following bugs:
1. Memory leak: under some circumstances the references of a process to a queue are not decremented correctly, which may prevent unused shared bfq_queue to be correctly deallocated.
2. Various errors related to hierarchical scheduling that may lead to kernel panics when the bfqio cgroup is used (see the changelogs of versions v3r4 onwards for details)
All versions below v3r3 contain a bug causing occasional kernel panics when moving a process to a new cgroup. In particolar, the panic occurs if:
1. the queue associated to the process was idle when the process was moved
2. a new disk request was inserted into the queue just after the move.