From 0985694a4b2fd1df66874f6ccfa5f41ac6458d7c Mon Sep 17 00:00:00 2001
From: Aaron Jacobs <jacobsa@google.com>
Date: Fri, 1 May 2015 11:17:15 +1000
Subject: [PATCH] Allow setting a parent context for all ops.

---
 connection.go          | 14 +++++++++++---
 fuseops/common_op.go   |  7 ++++---
 fuseops/convert.go     |  5 ++++-
 mounted_file_system.go | 12 +++++++++++-
 4 files changed, 30 insertions(+), 8 deletions(-)

diff --git a/connection.go b/connection.go
index 6083b22..cc0b657 100644
--- a/connection.go
+++ b/connection.go
@@ -21,6 +21,8 @@ import (
 	"runtime"
 	"sync"
 
+	"golang.org/x/net/context"
+
 	"github.com/jacobsa/bazilfuse"
 	"github.com/jacobsa/fuse/fuseops"
 )
@@ -31,6 +33,9 @@ type Connection struct {
 	wrapped     *bazilfuse.Conn
 	opsInFlight sync.WaitGroup
 
+	// The context from which all op contexts inherit.
+	parentCtx context.Context
+
 	// For logging purposes only.
 	nextOpID uint32
 }
@@ -38,11 +43,13 @@ type Connection struct {
 // Responsibility for closing the wrapped connection is transferred to the
 // result. You must call c.close() eventually.
 func newConnection(
+	parentCtx context.Context,
 	logger *log.Logger,
 	wrapped *bazilfuse.Conn) (c *Connection, err error) {
 	c = &Connection{
-		logger:  logger,
-		wrapped: wrapped,
+		logger:    logger,
+		wrapped:   wrapped,
+		parentCtx: parentCtx,
 	}
 
 	return
@@ -115,7 +122,8 @@ func (c *Connection) ReadOp() (op fuseops.Op, err error) {
 			c.log(opID, calldepth+1, format, v...)
 		}
 
-		if op = fuseops.Convert(bfReq, logForOp, &c.opsInFlight); op == nil {
+		op = fuseops.Convert(c.parentCtx, bfReq, logForOp, &c.opsInFlight)
+		if op == nil {
 			c.log(opID, 1, "-> ENOSYS: %v", bfReq)
 			bfReq.RespondError(ENOSYS)
 			continue
diff --git a/fuseops/common_op.go b/fuseops/common_op.go
index 99364d1..204016b 100644
--- a/fuseops/common_op.go
+++ b/fuseops/common_op.go
@@ -25,12 +25,13 @@ import (
 
 // A helper for embedding common behavior.
 type commonOp struct {
-	ctx         context.Context
 	opType      string
 	r           bazilfuse.Request
 	log         func(int, string, ...interface{})
 	opsInFlight *sync.WaitGroup
-	report      reqtrace.ReportFunc
+
+	ctx    context.Context
+	report reqtrace.ReportFunc
 }
 
 func describeOpType(t reflect.Type) (desc string) {
@@ -40,13 +41,13 @@ func describeOpType(t reflect.Type) (desc string) {
 }
 
 func (o *commonOp) init(
+	ctx context.Context,
 	opType reflect.Type,
 	r bazilfuse.Request,
 	log func(int, string, ...interface{}),
 	opsInFlight *sync.WaitGroup) {
 	// Initialize basic fields.
 	o.opType = describeOpType(opType)
-	o.ctx = context.Background()
 	o.r = r
 	o.log = log
 	o.opsInFlight = opsInFlight
diff --git a/fuseops/convert.go b/fuseops/convert.go
index 8dc7ac8..ef4a297 100644
--- a/fuseops/convert.go
+++ b/fuseops/convert.go
@@ -19,6 +19,8 @@ import (
 	"sync"
 	"time"
 
+	"golang.org/x/net/context"
+
 	"github.com/jacobsa/bazilfuse"
 )
 
@@ -28,6 +30,7 @@ import (
 // This function is an implementation detail of the fuse package, and must not
 // be called by anyone else.
 func Convert(
+	parentCtx context.Context,
 	r bazilfuse.Request,
 	logForOp func(int, string, ...interface{}),
 	opsInFlight *sync.WaitGroup) (o Op) {
@@ -213,7 +216,7 @@ func Convert(
 		return
 	}
 
-	co.init(reflect.TypeOf(o), r, logForOp, opsInFlight)
+	co.init(parentCtx, reflect.TypeOf(o), r, logForOp, opsInFlight)
 	return
 }
 
diff --git a/mounted_file_system.go b/mounted_file_system.go
index 6772793..f814378 100644
--- a/mounted_file_system.go
+++ b/mounted_file_system.go
@@ -61,6 +61,10 @@ func (mfs *MountedFileSystem) Join(ctx context.Context) error {
 
 // Optional configuration accepted by Mount.
 type MountConfig struct {
+	// The context from which every op read from the connetion by the sever
+	// should inherit. If nil, context.Background() will be used.
+	OpContext context.Context
+
 	// OS X only.
 	//
 	// Normally on OS X we mount with the novncache option
@@ -127,8 +131,14 @@ func Mount(
 		return
 	}
 
+	// Choose a parent context for ops.
+	opContext := config.OpContext
+	if opContext == nil {
+		opContext = context.Background()
+	}
+
 	// Create our own Connection object wrapping it.
-	connection, err := newConnection(logger, bfConn)
+	connection, err := newConnection(opContext, logger, bfConn)
 	if err != nil {
 		bfConn.Close()
 		err = fmt.Errorf("newConnection: %v", err)