Correct compilation errors reported by GCC 10/11

New `zfs_type_t` value `ZFS_TYPE_INVALID` is introduced.
Variable initialization is now possible to make GCC happy.

Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: szubersk <szuberskidamian@gmail.com>
Closes #12167
Closes #13103

lib/libzfs/libzfs_dataset.c

@@ -3972,13 +3972,10 @@ zfs_clone(zfs_handle_t *zhp, const char *target, nvlist_t *props)
 	/* do the clone */
 
 	if (props) {
-		zfs_type_t type;
+		zfs_type_t type = ZFS_TYPE_FILESYSTEM;
 
-		if (ZFS_IS_VOLUME(zhp)) {
+		if (ZFS_IS_VOLUME(zhp))
 			type = ZFS_TYPE_VOLUME;
-		} else {
-			type = ZFS_TYPE_FILESYSTEM;
-		}
 		if ((props = zfs_valid_proplist(hdl, type, props, zoned,
 		    zhp, zhp->zpool_hdl, B_TRUE, errbuf)) == NULL)
 			return (-1);

lib/libzfs/libzfs_sendrecv.c

@@ -807,8 +807,9 @@ dump_ioctl(zfs_handle_t *zhp, const char *fromsnap, uint64_t fromsnap_obj,
 		char errbuf[1024];
 		int error = errno;
 
-		(void) snprintf(errbuf, sizeof (errbuf), dgettext(TEXT_DOMAIN,
-		    "warning: cannot send '%s'"), zhp->zfs_name);
+		(void) snprintf(errbuf, sizeof (errbuf), "%s '%s'",
+		    dgettext(TEXT_DOMAIN, "warning: cannot send"),
+		    zhp->zfs_name);
 
 		if (debugnv != NULL) {
 			fnvlist_add_uint64(thisdbg, "error", error);
@@ -4196,7 +4197,7 @@ zfs_receive_one(libzfs_handle_t *hdl, int infd, const char *tosnap,
 	nvlist_t *rcvprops = NULL; /* props received from the send stream */
 	nvlist_t *oxprops = NULL; /* override (-o) and exclude (-x) props */
 	nvlist_t *origprops = NULL; /* original props (if destination exists) */
-	zfs_type_t type;
+	zfs_type_t type = ZFS_TYPE_INVALID;
 	boolean_t toplevel = B_FALSE;
 	boolean_t zoned = B_FALSE;
 	boolean_t hastoken = B_FALSE;

lib/libzfs/os/freebsd/libzfs_compat.c

@@ -199,7 +199,7 @@ execvpe(const char *name, char * const argv[], char * const envp[])
 	return (execvPe(name, path, argv, envp));
 }
 
-#define	ERRBUFLEN 256
+#define	ERRBUFLEN 1024
 
 static __thread char errbuf[ERRBUFLEN];
 
@@ -207,10 +207,10 @@ const char *
 libzfs_error_init(int error)
 {
 	char *msg = errbuf;
-	size_t len, msglen = ERRBUFLEN;
+	size_t msglen = sizeof (errbuf);
 
 	if (modfind("zfs") < 0) {
-		len = snprintf(msg, msglen, dgettext(TEXT_DOMAIN,
+		size_t len = snprintf(msg, msglen, dgettext(TEXT_DOMAIN,
 		    "Failed to load %s module: "), ZFS_KMOD);
 		msg += len;
 		msglen -= len;
@@ -285,7 +285,6 @@ zfs_jail(zfs_handle_t *zhp, int jailid, int attach)
 {
 	libzfs_handle_t *hdl = zhp->zfs_hdl;
 	zfs_cmd_t zc = {"\0"};
-	char errbuf[1024];
 	unsigned long cmd;
 	int ret;
 
@@ -314,6 +313,10 @@ zfs_jail(zfs_handle_t *zhp, int jailid, int attach)
 		zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
 		    "vdevs can not be jailed"));
 		return (zfs_error(hdl, EZFS_BADTYPE, errbuf));
+	case ZFS_TYPE_INVALID:
+		zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
+		    "invalid zfs_type_t: ZFS_TYPE_INVALID"));
+		return (zfs_error(hdl, EZFS_BADTYPE, errbuf));
 	case ZFS_TYPE_POOL:
 	case ZFS_TYPE_FILESYSTEM:
 		/* OK */

lib/libzutil/os/linux/zutil_import_os.c

@@ -754,6 +754,9 @@ no_dev:
 
 	return (ret);
 #else
+	(void) path;
+	(void) ds;
+	(void) wholedisk;
 	return (ENOENT);
 #endif
 }