- Add a sysctl kern.geom.mirror.idletime, so one can specify after how many   seconds of idling, DRITY flags are removed. - If mirror is in idle state or is not open for writing, sleep without   timeout when waiting for I/O requests. - Don't use atomic operations, for now sysctls are protected by Giant. - Update debugs.
- Add a sysctl kern.geom.mirror.idletime, so one can specify after how many
  seconds of idling, DRITY flags are removed.
- If mirror is in idle state or is not open for writing, sleep without
  timeout when waiting for I/O requests.
- Don't use atomic operations, for now sysctls are protected by Giant.
- Update debugs.

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase