OpenZFS 6550 - cmd/zfs: cleanup gcc warnings

Porting Notes:
- Many of the fixes proposed by this patch were already applied.
In the cases where a different but equivalent fix was made the
code was updated with the OpenZFS version to minimize differences.

Authored by: Igor Kozhukhov <ikozhukhov@gmail.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Andy Stormont <astormont@racktopsystems.com>
Approved by: Dan McDonald <danmcd@omniti.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>

OpenZFS-issue: https://www.illumos.org/issues/6550
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/c16bcc4
Closes #5591

cmd/zfs/zfs_main.c

@@ -26,6 +26,7 @@
  * Copyright (c) 2012, Joyent, Inc. All rights reserved.
  * Copyright (c) 2013 Steven Hartland.  All rights reserved.
  * Copyright 2013 Nexenta Systems, Inc.  All rights reserved.
+ * Copyright 2016 Igor Kozhukhov <ikozhukhov@gmail.com>.
  */
 
 #include <assert.h>
@@ -857,7 +858,7 @@ zfs_do_create(int argc, char **argv)
 		char *strval;
 		char msg[1024];
 
-		if ((p = strchr(argv[0], '/')))
+		if ((p = strchr(argv[0], '/')) != NULL)
 			*p = '\0';
 		zpool_handle = zpool_open(g_zfs, argv[0]);
 		if (p != NULL)
@@ -2353,6 +2354,7 @@ compare_nums:
 			if (rv64 != lv64)
 				rc = (rv64 < lv64) ? 1 : -1;
 			break;
+
 		default:
 			break;
 		}
@@ -3980,7 +3982,7 @@ zfs_do_send(int argc, char **argv)
 static int
 zfs_do_receive(int argc, char **argv)
 {
-	int c, err;
+	int c, err = 0;
 	recvflags_t flags = { 0 };
 	boolean_t abort_resumable = B_FALSE;
 
@@ -4263,7 +4265,7 @@ deleg_perm_type(zfs_deleg_note_t note)
 	}
 }
 
-static int inline
+static int
 who_type2weight(zfs_deleg_who_type_t who_type)
 {
 	int res;
@@ -4483,7 +4485,7 @@ fs_perm_fini(fs_perm_t *fsperm)
 	uu_avl_destroy(fsperm->fsp_uge_avl);
 }
 
-static void inline
+static void
 set_deleg_perm_node(uu_avl_t *avl, deleg_perm_node_t *node,
     zfs_deleg_who_type_t who_type, const char *name, char locality)
 {
@@ -4580,8 +4582,9 @@ parse_fs_perm(fs_perm_t *fsperm, nvlist_t *nvl)
 			avl_pool = fspset->fsps_who_perm_avl_pool;
 			avl = fsperm->fsp_uge_avl;
 			break;
+
 		default:
-			break;
+			assert(!"unhandled zfs_deleg_who_type_t");
 		}
 
 		if (is_set) {
@@ -4617,6 +4620,7 @@ parse_fs_perm(fs_perm_t *fsperm, nvlist_t *nvl)
 						if (g)
 							nice_name = g->gr_name;
 						break;
+
 					default:
 						break;
 					}
@@ -4954,8 +4958,8 @@ store_allow_perm(zfs_deleg_who_type_t type, boolean_t local, boolean_t descend,
 	int i;
 	char ld[2] = { '\0', '\0' };
 	char who_buf[MAXNAMELEN + 32];
-	char base_type = ZFS_DELEG_WHO_UNKNOWN;
+	char base_type = '\0';
-	char set_type = ZFS_DELEG_WHO_UNKNOWN;
+	char set_type = '\0';
 	nvlist_t *base_nvl = NULL;
 	nvlist_t *set_nvl = NULL;
 	nvlist_t *nvl;
@@ -5004,8 +5008,10 @@ store_allow_perm(zfs_deleg_who_type_t type, boolean_t local, boolean_t descend,
 			ld[0] = ZFS_DELEG_LOCAL;
 		if (descend)
 			ld[1] = ZFS_DELEG_DESCENDENT;
-	default:
 		break;
+
+	default:
+		assert(set_type != '\0' && base_type != '\0');
 	}
 
 	if (perms != NULL) {
@@ -5239,7 +5245,7 @@ print_set_creat_perms(uu_avl_t *who_avl)
 	}
 }
 
-static void inline
+static void
 print_uge_deleg_perms(uu_avl_t *who_avl, boolean_t local, boolean_t descend,
     const char *title)
 {
@@ -5290,8 +5296,10 @@ print_uge_deleg_perms(uu_avl_t *who_avl, boolean_t local, boolean_t descend,
 				case ZFS_DELEG_EVERYONE:
 					who = gettext("everyone");
 					who_name = NULL;
-				default:
 					break;
+
+				default:
+					assert(who != NULL);
 				}
 
 				prt_who = B_FALSE;
@@ -5996,10 +6004,10 @@ share_mount_one(zfs_handle_t *zhp, int op, int flags, char *protocol,
 		shared_smb = zfs_is_shared_smb(zhp, NULL);
 
 		if ((shared_nfs && shared_smb) ||
-		    ((shared_nfs && strcmp(shareopts, "on") == 0) &&
+		    (shared_nfs && strcmp(shareopts, "on") == 0 &&
-		    (strcmp(smbshareopts, "off") == 0)) ||
+		    strcmp(smbshareopts, "off") == 0) ||
-		    ((shared_smb && strcmp(smbshareopts, "on") == 0) &&
+		    (shared_smb && strcmp(smbshareopts, "on") == 0 &&
-		    (strcmp(shareopts, "off") == 0))) {
+		    strcmp(shareopts, "off") == 0)) {
 			if (!explicit)
 				return (0);
 
@@ -6787,7 +6795,7 @@ zfs_do_diff(int argc, char **argv)
 	if (copy == NULL)
 		usage(B_FALSE);
 
-	if ((atp = strchr(copy, '@')))
+	if ((atp = strchr(copy, '@')) != NULL)
 		*atp = '\0';
 
 	if ((zhp = zfs_open(g_zfs, copy, ZFS_TYPE_FILESYSTEM)) == NULL) {

include/sys/fs/zfs.h

@@ -82,7 +82,8 @@ typedef enum dmu_objset_type {
  * the property table in module/zcommon/zfs_prop.c.
  */
 typedef enum {
-	ZFS_PROP_TYPE,
+	ZFS_PROP_BAD = -1,
+	ZFS_PROP_TYPE = 0,
 	ZFS_PROP_CREATION,
 	ZFS_PROP_USED,
 	ZFS_PROP_AVAILABLE,