vdev_mirror: load balancing fixes
vdev_queue:
- Track the last position of each vdev, including the io size, in order to detect linear access of the following zio.
- Remove duplicate vq_lastoffset
vdev_mirror:
- Correctly calculate the zio offset (signedness issue)
- Deprecate vdev_queue_register_lastoffset()
- Add VDEV_LABEL_START_SIZE to zio offset of leaf vdevs
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Gvozden Neskovic <neskovic@gmail.com>
Closes #6461