Index: lib/libnv/Makefile
===================================================================
--- lib/libnv/Makefile
+++ lib/libnv/Makefile
@@ -24,6 +24,7 @@
 MLINKS+=nv.3 nvlist_create.3 \
 	nv.3 nvlist_destroy.3 \
 	nv.3 nvlist_error.3 \
+	nv.3 nvlist_set_error.3 \
 	nv.3 nvlist_empty.3 \
 	nv.3 nvlist_clone.3 \
 	nv.3 nvlist_dump.3 \
Index: lib/libnv/nv.h
===================================================================
--- lib/libnv/nv.h
+++ lib/libnv/nv.h
@@ -68,6 +68,7 @@
 void		 nvlist_destroy(nvlist_t *nvl);
 int		 nvlist_error(const nvlist_t *nvl);
 bool		 nvlist_empty(const nvlist_t *nvl);
+void		 nvlist_set_error(nvlist_t *nvl, int error);
 
 nvlist_t *nvlist_clone(const nvlist_t *nvl);
 
Index: lib/libnv/nv.3
===================================================================
--- lib/libnv/nv.3
+++ lib/libnv/nv.3
@@ -35,6 +35,7 @@
 .Nm nvlist_create ,
 .Nm nvlist_destroy ,
 .Nm nvlist_error ,
+.Nm nvlist_set_error ,
 .Nm nvlist_empty ,
 .Nm nvlist_exists ,
 .Nm nvlist_free ,
@@ -63,6 +64,8 @@
 .Fn nvlist_destroy "nvlist_t *nvl"
 .Ft int
 .Fn nvlist_error "const nvlist_t *nvl"
+.Ft void
+.Fn nvlist_set_error "nvlist_t *nvl, int error"
 .Ft bool
 .Fn nvlist_empty "const nvlist_t *nvl"
 .\"
@@ -248,8 +251,17 @@
 error will be returned.
 .Pp
 The
+.Fn nvlist_set_error
+function sets an nvlist to be in the error state.
+Subsequent calls to
+.Fn nvlist_error
+will return the given error value.
+This function cannot be used to clear the error state from an nvlist.
+This function does nothing if the nvlist is already in the error state.
+.Pp
+The
 .Fn nvlist_empty
-functions returns
+function returns
 .Dv true
 if the given nvlist is empty and
 .Dv false
Index: lib/libnv/nvlist.c
===================================================================
--- lib/libnv/nvlist.c
+++ lib/libnv/nvlist.c
@@ -137,6 +137,14 @@
 	errno = serrno;
 }
 
+void
+nvlist_set_error(nvlist_t *nvl, int error)
+{
+
+	if (nvl != NULL && error != 0 && nvl->nvl_error == 0)
+		nvl->nvl_error = error;
+}
+
 int
 nvlist_error(const nvlist_t *nvl)
 {
Index: lib/libnv/tests/nv_tests.cc
===================================================================
--- lib/libnv/tests/nv_tests.cc
+++ lib/libnv/tests/nv_tests.cc
@@ -406,6 +406,22 @@
 	nvlist_destroy(nvl);
 }
 
+ATF_TEST_CASE_WITHOUT_HEAD(nvlist_clone__error_nvlist);
+ATF_TEST_CASE_BODY(nvlist_clone__error_nvlist)
+{
+	nvlist_t *nvl, *clone;
+
+	nvl = nvlist_create(0);
+	ATF_REQUIRE(nvl != NULL);
+
+	nvlist_set_error(nvl, ENOMEM);
+
+	clone = nvlist_clone(nvl);
+	ATF_REQUIRE(clone == NULL);
+
+	nvlist_destroy(nvl);
+}
+
 ATF_TEST_CASE_WITHOUT_HEAD(nvlist_pack__empty_nvlist);
 ATF_TEST_CASE_BODY(nvlist_pack__empty_nvlist)
 {
@@ -547,6 +563,24 @@
 	free(packed);
 }
 
+ATF_TEST_CASE_WITHOUT_HEAD(nvlist_pack__error_nvlist);
+ATF_TEST_CASE_BODY(nvlist_pack__error_nvlist)
+{
+	nvlist_t *nvl;
+	void *packed;
+	size_t size;
+
+	nvl = nvlist_create(0);
+	ATF_REQUIRE(nvl != NULL);
+
+	nvlist_set_error(nvl, ENOMEM);
+
+	packed = nvlist_pack(nvl, &size);
+	ATF_REQUIRE(packed == NULL);
+
+	nvlist_destroy(nvl);
+}
+
 ATF_TEST_CASE_WITHOUT_HEAD(nvlist_unpack__duplicate_key);
 ATF_TEST_CASE_BODY(nvlist_unpack__duplicate_key)
 {
@@ -1145,9 +1179,11 @@
 	ATF_ADD_TEST_CASE(tp, nvlist_clone__empty_nvlist);
 	ATF_ADD_TEST_CASE(tp, nvlist_clone__nonempty_nvlist);
 	ATF_ADD_TEST_CASE(tp, nvlist_clone__nested_nvlist);
+	ATF_ADD_TEST_CASE(tp, nvlist_clone__error_nvlist);
 
 	ATF_ADD_TEST_CASE(tp, nvlist_pack__empty_nvlist);
 	ATF_ADD_TEST_CASE(tp, nvlist_pack__multiple_values);
+	ATF_ADD_TEST_CASE(tp, nvlist_pack__error_nvlist);
 	ATF_ADD_TEST_CASE(tp, nvlist_unpack__duplicate_key);
 
 	ATF_ADD_TEST_CASE(tp, nvlist_move_string__single_insert);