+ * Returns true if this is a valid written@ property.
+ * Note that after the @, any character is valid (eg, another @, for
+ * written@pool/fs@origin).
+ */
+boolean_t
+zfs_prop_written(const char *name)
+{
+ static const char *prefix = "written@";
+ return (strncmp(name, prefix, strlen(prefix)) == 0);
+}
+
+/*