Add -u option to 'zfs create'

Add -u option to 'zfs create' that prevents file system from being
automatically mounted. This is similar to the 'zfs receive -u'.

Authored by: pjd <pjd@FreeBSD.org>
FreeBSD-commit: freebsd/freebsd@35c58230e2

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Allan Jude <allan@klarasystems.com>
Ported-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes #11254

tests/zfs-tests/tests/functional/cli_root/zfs_create/Makefile.am

@@ -19,6 +19,7 @@ dist_pkgdata_SCRIPTS = \
 	zfs_create_encrypted.ksh \
 	zfs_create_crypt_combos.ksh \
 	zfs_create_dryrun.ksh \
+	zfs_create_nomount.ksh \
 	zfs_create_verbose.ksh
 
 dist_pkgdata_DATA = \

tests/zfs-tests/tests/functional/cli_root/zfs_create/zfs_create_nomount.ksh

@@ -0,0 +1,51 @@
+#!/bin/ksh -p
+#
+# This file and its contents are supplied under the terms of the
+# Common Development and Distribution License ("CDDL"), version 1.0.
+# You may only use this file in accordance with the terms of version
+# 1.0 of the CDDL.
+#
+# A full copy of the text of the CDDL should have accompanied this
+# source.  A copy of the CDDL is also available via the Internet at
+# http://www.illumos.org/license/CDDL.
+#
+
+#
+# Copyright 2020 iXsystems, Inc.
+#
+
+. $STF_SUITE/include/libtest.shlib
+
+#
+# DESCRIPTION:
+# zfs create -u should leave the new file system unmounted.
+# It should not work for a volume.
+#
+# STRATEGY:
+# 1. Create a file system using -u and make sure the file system is not mounted.
+# 3. Do it for a volume to verify it fails.
+#
+
+verify_runnable "both"
+
+function cleanup
+{
+	local ds
+
+	for ds in "$fs" "$vol"; do
+		datasetexists "$ds" && destroy_dataset "$ds"
+	done
+}
+log_onexit cleanup
+
+log_assert "zfs create -u leaves the new file system unmounted"
+
+typeset fs="$TESTPOOL/$TESTFS1"
+typeset vol="$TESTPOOL/$TESTVOL1"
+
+log_must create_dataset "$fs" "-u"
+log_mustnot ismounted "$fs"
+
+log_mustnot zfs create -V $VOLSIZE -u "$vol"
+
+log_pass "zfs create -u leaves the new file system unmounted"