Porting notes:
* Two of the three changes from the upstream patch were already
applied for Linux. Only the last one is required.
Authored by: Yuri Pankov <yuri.pankov@nexenta.com>
Reviewed by: Robert Mustacchi <rm@joyent.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Approved by: Gordon Ross <gwr@nexenta.com>
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
OpenZFS-issue: https://illumos.org/issues/9763
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/8a702e55Closes#7972