I/O control, synchronization method in a raid environment with co-existing hardware and software-based I/O paths

摘要

The present invention is directed to a command block protocol which may implemented by RAID firmware for synchronizing I/Os in a RAID system which includes co-existing hardware and software-based I/O paths. The command block protocol of the present disclosure ensures that there aren't any I/Os outstanding in the fast path or any other hardware engine by making sure that the region lock (ex.—Sentinel Region Lock) is taken for the entire size of the volume. When the Sentinel Region Lock is granted, the RAID firmware may assume that there aren't any commands outstanding in the fast path hardware or pending for the region lock to be obtained. The RAID firmware would not be able to maintain integrity of user data in the absence of the new command block protocol disclosed herein.

主权项

1. A method for providing I/O control and synchronization in a RAID system which includes co-existing hardware and software-based I/O paths, said method comprising:
detecting a need to take a command block via firmware, the command block including at least one of blocking at least one host command and pausing at least one active background operation; establishing a host I/O bit of a control register of fast path hardware of the system at a first setting for preventing the fast path hardware from processing subsequent host I/Os posted by a host driver through a request first-in first-out (FIFO) buffer of the controller; and allowing the fast path hardware to complete servicing a last I/O fetched after the first setting of the host I/O bit was established.