ircd::fs::opts: Add an option to suppress internal error logging on some operations.

include/ircd/fs/opts.h

@@ -60,6 +60,10 @@ struct ircd::fs::opts
 	/// opcode and then pass the opts structure to write().
 	enum op op {op::NOOP};
 
+	/// Suppress logging of some expected/tolerated failures. Set to false
+	/// if the call should just silently rethrow.
+	bool errlog {true};
+
 	opts(const off_t &, const enum op & = op::NOOP);
 	opts() = default;
 };

ircd/fs.cc

@@ -2028,12 +2028,13 @@ try
 }
 catch(const std::system_error &e)
 {
-	log::derror
-	{
-		log, "`%s' :%s",
-		path,
-		e.what(),
-	};
+	if(opts.errlog)
+		log::derror
+		{
+			log, "`%s' :%s",
+			path,
+			e.what(),
+		};
 
 	throw;
 }