settings: zms: add more robustness to the save function

When a power off happens after writing the settings name and before
writing the linked list node we cannot write the settings name again in
the future.
Fix this by writing the linked list node before writing the name.
When loading all settings, we already delete linked list node that do
not have any name or value written.

Signed-off-by: Riadh Ghaddab <[email protected]>

Author: rghaddab

subsys/settings/src/settings_zms.c

@@ -513,10 +513,7 @@ static int settings_zms_save(struct settings_store *cs, const char *name, const
 
 	/* write the name if required */
 	if (write_name) {
-		rc = zms_write(&cf->cf_zms, name_hash, name, strlen(name));
-		if (rc < 0) {
-			return rc;
-		}
+		/* First let's update the linked list */
 #ifdef CONFIG_SETTINGS_ZMS_NO_LL_DELETE
 		if (ll_node_exist) {
 			goto no_ll_update;
@@ -570,10 +567,16 @@ static int settings_zms_save(struct settings_store *cs, const char *name, const
 			cf->ll_cache[cf->ll_cache_next - 2] = settings_element;
 		}
 #endif
-	}
 #ifdef CONFIG_SETTINGS_ZMS_NO_LL_DELETE
 no_ll_update:
 #endif /* CONFIG_SETTINGS_ZMS_NO_LL_DELETE */
+		/* Now let's write the name */
+		rc = zms_write(&cf->cf_zms, name_hash, name, strlen(name));
+		if (rc < 0) {
+			return rc;
+		}
+	}
+
 #ifdef CONFIG_SETTINGS_ZMS_NAME_CACHE
 	/* Add the flags of the written settings entry in cache */
 	cache_flags = 0;