Support setting user properties in a channel program

This adds support for setting user properties in a
zfs channel program by adding 'zfs.sync.set_prop'
and 'zfs.check.set_prop' to the ZFS LUA API.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matt Ahrens <matt@delphix.com>
Co-authored-by: Sara Hartse <sara.hartse@delphix.com>
Contributions-by: Jason King <jason.king@joyent.com>
Signed-off-by: Sara Hartse <sara.hartse@delphix.com>
Signed-off-by: Jason King <jason.king@joyent.com>
Closes #9950

include/sys/Makefile.am

@@ -99,6 +99,7 @@ COMMON_H = \
 	$(top_srcdir)/include/sys/zcp_global.h \
 	$(top_srcdir)/include/sys/zcp_iter.h \
 	$(top_srcdir)/include/sys/zcp_prop.h \
+	$(top_srcdir)/include/sys/zcp_set.h \
 	$(top_srcdir)/include/sys/zfeature.h \
 	$(top_srcdir)/include/sys/zfs_acl.h \
 	$(top_srcdir)/include/sys/zfs_context.h \

include/sys/zcp_set.h

@@ -0,0 +1,44 @@
+/*
+ * CDDL HEADER START
+ *
+ * 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.
+ *
+ * CDDL HEADER END
+ */
+
+/*
+ * Copyright 2019 Joyent, Inc.
+ */
+
+#ifndef _SYS_ZCP_SET_H
+#define	_SYS_ZCP_SET_H
+
+#include <sys/dmu_tx.h>
+#include <sys/dsl_pool.h>
+
+#ifdef  __cplusplus
+extern "C" {
+#endif
+
+typedef struct zcp_set_prop_arg {
+	lua_State	*state;
+	const char	*dsname;
+	const char	*prop;
+	const char	*val;
+} zcp_set_prop_arg_t;
+
+int zcp_set_prop_check(void *arg, dmu_tx_t *tx);
+void zcp_set_prop_sync(void *arg, dmu_tx_t *tx);
+
+#ifdef  __cplusplus
+}
+#endif
+
+#endif /* _SYS_ZCP_SET_H */