OpenZFS 8652 - Tautological comparisons with ZPROP_INVAL

usr/src/uts/common/sys/fs/zfs.h
	Change ZPROP_INVAL and ZPROP_CONT from macros to enum values.  Clang
	and GCC both prefer to use unsigned ints to store enums.  That was
	causing tautological comparison warnings (and likely eliminating
	error handling code at compile time) whenever a zfs_prop_t or
	zpool_prop_t was compared to ZPROP_INVAL or ZPROP_CONT.  Making the
	error flags be explicity enum values forces the enum types to be
	signed.

	ZPROP_INVAL was also compared against two different enum types.  I
	had to change its name to ZPOOL_PROP_INVAL whenever its compared to
	a zpool_prop_t.  There are still some places where ZPROP_INVAL or
	ZPROP_CONT is compared to a plain int, in code that doesn't know
	whether the int is storing a zfs_prop_t or a zpool_prop_t.

usr/src/uts/common/fs/zfs/spa.c
	s/ZPROP_INVAL/ZPOOL_PROP_INVAL/

Authored by: Alan Somers <asomers@gmail.com>
Approved by: Gordon Ross <gwr@nexenta.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Igor Kozhukhov <igor@dilos.org>
Reviewed by: George Melikov <mail@gmelikov.ru>
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>

OpenZFS-issue: https://www.illumos.org/issues/8652
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/c2de80dc74
Closes #7061

cmd/zpool/zpool_main.c

@@ -511,7 +511,7 @@ static int
 add_prop_list(const char *propname, char *propval, nvlist_t **props,
     boolean_t poolprop)
 {
-	zpool_prop_t prop = ZPROP_INVAL;
+	zpool_prop_t prop = ZPOOL_PROP_INVAL;
 	zfs_prop_t fprop;
 	nvlist_t *proplist;
 	const char *normnm;
@@ -529,7 +529,7 @@ add_prop_list(const char *propname, char *propval, nvlist_t **props,
 	if (poolprop) {
 		const char *vname = zpool_prop_to_name(ZPOOL_PROP_VERSION);
 
-		if ((prop = zpool_name_to_prop(propname)) == ZPROP_INVAL &&
+		if ((prop = zpool_name_to_prop(propname)) == ZPOOL_PROP_INVAL &&
 		    !zpool_prop_feature(propname)) {
 			(void) fprintf(stderr, gettext("property '%s' is "
 			    "not a valid pool property\n"), propname);
@@ -540,7 +540,7 @@ add_prop_list(const char *propname, char *propval, nvlist_t **props,
 		 * feature@ properties and version should not be specified
 		 * at the same time.
 		 */
-		if ((prop == ZPROP_INVAL && zpool_prop_feature(propname) &&
+		if ((prop == ZPOOL_PROP_INVAL && zpool_prop_feature(propname) &&
 		    nvlist_exists(proplist, vname)) ||
 		    (prop == ZPOOL_PROP_VERSION &&
 		    prop_list_contains_feature(proplist))) {

include/sys/fs/zfs.h

@@ -88,7 +88,8 @@ typedef enum dmu_objset_type {
  * the property table in module/zcommon/zfs_prop.c.
  */
 typedef enum {
-	ZFS_PROP_BAD = -1,
+	ZPROP_CONT = -2,
+	ZPROP_INVAL = -1,
 	ZFS_PROP_TYPE = 0,
 	ZFS_PROP_CREATION,
 	ZFS_PROP_USED,
@@ -203,6 +204,7 @@ extern const char *zfs_userquota_prop_prefixes[ZFS_NUM_USERQUOTA_PROPS];
  * the property table in module/zcommon/zpool_prop.c.
  */
 typedef enum {
+	ZPOOL_PROP_INVAL = -1,
 	ZPOOL_PROP_NAME,
 	ZPOOL_PROP_SIZE,
 	ZPOOL_PROP_CAPACITY,
@@ -238,9 +240,6 @@ typedef enum {
 /* Small enough to not hog a whole line of printout in zpool(1M). */
 #define	ZPROP_MAX_COMMENT	32
 
-#define	ZPROP_CONT		-2
-#define	ZPROP_INVAL		-1
-
 #define	ZPROP_VALUE		"value"
 #define	ZPROP_SOURCE		"source"
 

lib/libzfs/libzfs_pool.c

@@ -460,7 +460,7 @@ zpool_valid_proplist(libzfs_handle_t *hdl, const char *poolname,
 		const char *propname = nvpair_name(elem);
 
 		prop = zpool_name_to_prop(propname);
-		if (prop == ZPROP_INVAL && zpool_prop_feature(propname)) {
+		if (prop == ZPOOL_PROP_INVAL && zpool_prop_feature(propname)) {
 			int err;
 			char *fname = strchr(propname, '@') + 1;
 
@@ -500,7 +500,7 @@ zpool_valid_proplist(libzfs_handle_t *hdl, const char *poolname,
 		/*
 		 * Make sure this property is valid and applies to this type.
 		 */
-		if (prop == ZPROP_INVAL) {
+		if (prop == ZPOOL_PROP_INVAL) {
 			zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
 			    "invalid property '%s'"), propname);
 			(void) zfs_error(hdl, EZFS_BADPROP, errbuf);

module/zfs/spa.c

@@ -353,7 +353,7 @@ spa_prop_get(spa_t *spa, nvlist_t **nvp)
 		zprop_source_t src = ZPROP_SRC_DEFAULT;
 		zpool_prop_t prop;
 
-		if ((prop = zpool_name_to_prop(za.za_name)) == ZPROP_INVAL)
+		if ((prop = zpool_name_to_prop(za.za_name)) == ZPOOL_PROP_INVAL)
 			continue;
 
 		switch (za.za_integer_length) {
@@ -440,8 +440,8 @@ spa_prop_validate(spa_t *spa, nvlist_t *props)
 		const char *propname = nvpair_name(elem);
 		zpool_prop_t prop = zpool_name_to_prop(propname);
 
-		switch ((int)prop) {
+		switch (prop) {
-		case ZPROP_INVAL:
+		case ZPOOL_PROP_INVAL:
 			if (!zpool_prop_feature(propname)) {
 				error = SET_ERROR(EINVAL);
 				break;
@@ -698,7 +698,7 @@ spa_prop_set(spa_t *spa, nvlist_t *nvp)
 		    prop == ZPOOL_PROP_READONLY)
 			continue;
 
-		if (prop == ZPOOL_PROP_VERSION || prop == ZPROP_INVAL) {
+		if (prop == ZPOOL_PROP_VERSION || prop == ZPOOL_PROP_INVAL) {
 			uint64_t ver;
 
 			if (prop == ZPOOL_PROP_VERSION) {
@@ -6541,9 +6541,8 @@ spa_sync_props(void *arg, dmu_tx_t *tx)
 		zprop_type_t proptype;
 		spa_feature_t fid;
 
-		prop = zpool_name_to_prop(nvpair_name(elem));
+		switch (prop = zpool_name_to_prop(nvpair_name(elem))) {
-		switch ((int)prop) {
+		case ZPOOL_PROP_INVAL:
-		case ZPROP_INVAL:
 			/*
 			 * We checked this earlier in spa_prop_validate().
 			 */