OpenZFS 8898 - creating fs with checksum=skein on the boot pools fails ungracefully

Authored by: Yuri Pankov <yuri.pankov@nexenta.com>
Reviewed by: Toomas Soome <tsoome@me.com>
Reviewed by: Andy Stormont <astormont@racktopsystems.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Approved by: Dan McDonald <danmcd@joyent.com>
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>

OpenZFS-issue: https://www.illumos.org/issues/8898
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/9fa2266d9a
Closes #7031

man/man8/zfs.8

@@ -29,7 +29,7 @@
 .\" Copyright 2016 Richard Laager. All rights reserved.
 .\" Copyright 2017 Nexenta Systems, Inc.
 .\"
-.Dd June 28, 2017
+.Dd January 10, 2018
 .Dt ZFS 8 SMM
 .Os Linux
 .Sh NAME
@@ -1099,6 +1099,10 @@ Please see
 for more information on these algorithms.
 .Pp
 Changing this property affects only newly-written data.
+.Pp
+Salted checksum algorithms
+.Pq Cm edonr , skein
+are currently not supported for any filesystem on the boot pools.
 .It Xo
 .Sy compression Ns = Ns Sy on Ns | Ns Sy off Ns | Ns Sy gzip Ns | Ns
 .Sy gzip- Ns Em N Ns | Ns Sy lz4 Ns | Ns Sy lzjb Ns | Ns Sy zle