zfs_refcount_*() are to be wrapped by zfsctl_snapshot_*() in this file. Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Reviewed-by: Tony Hutter <hutter2@llnl.gov> Signed-off-by: Tomohiro Kusumi <kusumi.tomohiro@gmail.com> Closes #9039