From 41f376af5f064f36b76f3a55812bd22d334bcc48 Mon Sep 17 00:00:00 2001
From: Aaron Jacobs <jacobsa@google.com>
Date: Mon, 25 May 2015 14:15:49 +1000
Subject: [PATCH] Added commonOp.errorLogger.

---
 fuseops/common_op.go   | 11 +++++++++++
 mounted_file_system.go |  3 ++-
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/fuseops/common_op.go b/fuseops/common_op.go
index ccf2d19..2ae773b 100644
--- a/fuseops/common_op.go
+++ b/fuseops/common_op.go
@@ -16,6 +16,7 @@ package fuseops
 
 import (
 	"fmt"
+	"log"
 	"reflect"
 	"strings"
 
@@ -50,6 +51,9 @@ type commonOp struct {
 	// first argument is a call depth.
 	debugLog func(int, string, ...interface{})
 
+	// A logger to be used for logging exceptional errors.
+	errorLogger *log.Logger
+
 	// A function that is invoked with the error given to Respond, for use in
 	// closing off traces and reporting back to the connection.
 	finished func(error)
@@ -77,12 +81,14 @@ func (o *commonOp) init(
 	op internalOp,
 	bazilReq bazilfuse.Request,
 	debugLog func(int, string, ...interface{}),
+	errorLogger *log.Logger,
 	finished func(error)) {
 	// Initialize basic fields.
 	o.ctx = ctx
 	o.op = op
 	o.bazilReq = bazilReq
 	o.debugLog = debugLog
+	o.errorLogger = errorLogger
 	o.finished = finished
 
 	// Set up a trace span for this op.
@@ -130,6 +136,11 @@ func (o *commonOp) Respond(err error) {
 		o.op.ShortDesc(),
 		err)
 
+	o.errorLogger.Printf(
+		"(%s) error: %v",
+		o.op.ShortDesc(),
+		err)
+
 	// Send a response to the kernel.
 	o.bazilReq.RespondError(err)
 }
diff --git a/mounted_file_system.go b/mounted_file_system.go
index e42d443..c3e8211 100644
--- a/mounted_file_system.go
+++ b/mounted_file_system.go
@@ -77,7 +77,8 @@ type MountConfig struct {
 	ReadOnly bool
 
 	// A logger to use for logging errors. All errors are logged, with the
-	// exception of a few blacklisted errors that are expected.
+	// exception of a few blacklisted errors that are expected. If nil, no error
+	// logging is performed.
 	ErrorLogger *log.Logger
 
 	// OS X only.