OpenZFS 8906 - uts: illumos rootfs should support salted cksum

Porting notes:
* As of grub-2.02 these checksums are not supported.  However, as
  pointed out in #6501 there are alternates see the issue for
  addition discussion.

Authored by: Toomas Soome <tsoome@me.com>
Reviewed by: C Fraire <cfraire@me.com>
Reviewed by: Robert Mustacchi <rm@joyent.com>
Reviewed by: Yuri Pankov <yuripv@yuripv.net>
Approved by: Dan McDonald <danmcd@joyent.com>
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>

OpenZFS-issue: https://illumos.org/issues/8906
OpenZFS-commit: openzfs/openzfs@7dec52f
Issue #6501

man/man5/zpool-features.5

@@ -14,7 +14,7 @@
 .\" CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your
 .\" own identifying information:
 .\" Portions Copyright [yyyy] [name of copyright owner]
-.TH ZPOOL-FEATURES 5 "Aug 27, 2013"
+.TH ZPOOL-FEATURES 5 "Jun 8, 2018"
 .SH NAME
 zpool\-features \- ZFS pool feature descriptions
 .SH DESCRIPTION
@@ -598,8 +598,7 @@ can turn on the \fBsha512\fR checksum on any dataset using the
 and will return to being \fBenabled\fR once all filesystems that have
 ever had their checksum set to \fBsha512\fR are destroyed.
 
-Booting off of pools utilizing SHA-512/256 is supported (provided that
-the updated GRUB stage2 module is installed).
+Booting off of pools utilizing SHA-512/256 is supported.
 
 .RE
 
@@ -633,9 +632,7 @@ can turn on the \fBskein\fR checksum on any dataset using the
 and will return to being \fBenabled\fR once all filesystems that have
 ever had their checksum set to \fBskein\fR are destroyed.
 
-Booting off of pools using \fBskein\fR is \fBNOT\fR supported
--- any attempt to enable \fBskein\fR on a root pool will fail with an
-error.
+Booting off of pools using \fBskein\fR is supported.
 
 .RE
 
@@ -675,9 +672,7 @@ can turn on the \fBedonr\fR checksum on any dataset using the
 and will return to being \fBenabled\fR once all filesystems that have
 ever had their checksum set to \fBedonr\fR are destroyed.
 
-Booting off of pools using \fBedonr\fR is \fBNOT\fR supported
--- any attempt to enable \fBedonr\fR on a root pool will fail with an
-error.
+Booting off of pools using \fBedonr\fR is supported.
 
 .RE
 

man/man8/zfs.8

@@ -30,7 +30,7 @@
 .\" Copyright 2017 Nexenta Systems, Inc.
 .\" Copyright 2018 Joyent, Inc.
 .\"
-.Dd January 10, 2018
+.Dd July 13, 2018
 .Dt ZFS 8 SMM
 .Os Linux
 .Sh NAME
@@ -1189,10 +1189,6 @@ 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

module/zfs/zfs_ioctl.c

@@ -4130,16 +4130,7 @@ zfs_check_settable(const char *dsname, nvpair_t *pair, cred_t *cr)
 
 		if ((err = spa_open(dsname, &spa, FTAG)) != 0)
 			return (err);
-		/*
-		 * Salted checksums are not supported on root pools.
-		 */
-		if (spa_bootfs(spa) != 0 &&
-		    intval < ZIO_CHECKSUM_FUNCTIONS &&
-		    (zio_checksum_table[intval].ci_flags &
-		    ZCHECKSUM_FLAG_SALTED)) {
-			spa_close(spa, FTAG);
-			return (SET_ERROR(ERANGE));
-		}
+
 		if (!spa_feature_is_enabled(spa, feature)) {
 			spa_close(spa, FTAG);
 			return (SET_ERROR(ENOTSUP));