diff --git a/connection.go b/connection.go
index 1c92dfb..3bfdb22 100644
--- a/connection.go
+++ b/connection.go
@@ -16,6 +16,7 @@ package fuse
 
 import (
 	"log"
+	"sync"
 
 	"github.com/jacobsa/bazilfuse"
 	"github.com/jacobsa/fuse/fuseops"
@@ -23,8 +24,9 @@ import (
 
 // A connection to the fuse kernel process.
 type Connection struct {
-	logger  *log.Logger
-	wrapped *bazilfuse.Conn
+	logger      *log.Logger
+	wrapped     *bazilfuse.Conn
+	opsInFlight sync.WaitGroup
 }
 
 // Responsibility for closing the wrapped connection is transferred to the
@@ -72,12 +74,13 @@ func (c *Connection) ReadOp() (op fuseops.Op, err error) {
 		}
 
 		// Convert it, if possible.
-		if op = fuseops.Convert(bfReq, c.logger); op == nil {
+		if op = fuseops.Convert(bfReq, c.logger, &c.opsInFlight); op == nil {
 			c.logger.Printf("Returning ENOSYS for unknown bazilfuse request: %v", bfReq)
 			bfReq.RespondError(ENOSYS)
 			continue
 		}
 
+		c.opsInFlight.Add(1)
 		return
 	}
 }
@@ -88,7 +91,9 @@ func (c *Connection) waitForReady() (err error) {
 	return
 }
 
+// Close the connection and wait for in-flight ops.
 func (c *Connection) close() (err error) {
 	err = c.wrapped.Close()
+	c.opsInFlight.Wait()
 	return
 }
diff --git a/fuseops/convert.go b/fuseops/convert.go
index 738321d..843c903 100644
--- a/fuseops/convert.go
+++ b/fuseops/convert.go
@@ -20,6 +20,7 @@ package fuseops
 import (
 	"log"
 	"reflect"
+	"sync"
 	"time"
 
 	"github.com/jacobsa/bazilfuse"
@@ -31,7 +32,10 @@ import (
 //
 // This function is an implementation detail of the fuse package, and must not
 // be called by anyone else.
-func Convert(r bazilfuse.Request, logger *log.Logger) (o Op) {
+func Convert(
+	r bazilfuse.Request,
+	logger *log.Logger,
+	opsInFlight *sync.WaitGroup) (o Op) {
 	var co *commonOp
 
 	switch typed := r.(type) {
@@ -214,7 +218,7 @@ func Convert(r bazilfuse.Request, logger *log.Logger) (o Op) {
 		return
 	}
 
-	co.init(reflect.TypeOf(o).String(), r, logger)
+	co.init(reflect.TypeOf(o).String(), r, logger, opsInFlight)
 	return
 }
 
@@ -264,20 +268,23 @@ func convertChildInodeEntry(
 
 // A helper for embedding common behavior.
 type commonOp struct {
-	opType string
-	ctx    context.Context
-	r      bazilfuse.Request
-	logger *log.Logger
+	opType      string
+	ctx         context.Context
+	r           bazilfuse.Request
+	logger      *log.Logger
+	opsInFlight *sync.WaitGroup
 }
 
 func (o *commonOp) init(
 	opType string,
 	r bazilfuse.Request,
-	logger *log.Logger) {
+	logger *log.Logger,
+	opsInFlight *sync.WaitGroup) {
 	o.opType = opType
 	o.ctx = context.Background()
 	o.r = r
 	o.logger = logger
+	o.opsInFlight = opsInFlight
 }
 
 func (o *commonOp) Header() OpHeader {
diff --git a/fuseops/ops.go b/fuseops/ops.go
index ea7af98..4f4e38b 100644
--- a/fuseops/ops.go
+++ b/fuseops/ops.go
@@ -53,6 +53,8 @@ type InitOp struct {
 }
 
 func (o *InitOp) Respond(err error) {
+	defer o.commonOp.opsInFlight.Done()
+
 	if err != nil {
 		o.commonOp.respondErr(err)
 		return
@@ -135,6 +137,8 @@ type LookUpInodeOp struct {
 }
 
 func (o *LookUpInodeOp) Respond(err error) {
+	defer o.commonOp.opsInFlight.Done()
+
 	if err != nil {
 		o.commonOp.respondErr(err)
 		return
@@ -165,6 +169,8 @@ type GetInodeAttributesOp struct {
 }
 
 func (o *GetInodeAttributesOp) Respond(err error) {
+	defer o.commonOp.opsInFlight.Done()
+
 	if err != nil {
 		o.commonOp.respondErr(err)
 		return
@@ -203,6 +209,8 @@ type SetInodeAttributesOp struct {
 }
 
 func (o *SetInodeAttributesOp) Respond(err error) {
+	defer o.commonOp.opsInFlight.Done()
+
 	if err != nil {
 		o.commonOp.respondErr(err)
 		return
@@ -267,6 +275,8 @@ type ForgetInodeOp struct {
 }
 
 func (o *ForgetInodeOp) Respond(err error) {
+	defer o.commonOp.opsInFlight.Done()
+
 	if err != nil {
 		o.commonOp.respondErr(err)
 		return
@@ -305,6 +315,8 @@ type MkDirOp struct {
 }
 
 func (o *MkDirOp) Respond(err error) {
+	defer o.commonOp.opsInFlight.Done()
+
 	if err != nil {
 		o.commonOp.respondErr(err)
 		return
@@ -361,6 +373,8 @@ type CreateFileOp struct {
 }
 
 func (o *CreateFileOp) Respond(err error) {
+	defer o.commonOp.opsInFlight.Done()
+
 	if err != nil {
 		o.commonOp.respondErr(err)
 		return
@@ -398,6 +412,8 @@ type RmDirOp struct {
 }
 
 func (o *RmDirOp) Respond(err error) {
+	defer o.commonOp.opsInFlight.Done()
+
 	if err != nil {
 		o.commonOp.respondErr(err)
 		return
@@ -422,6 +438,8 @@ type UnlinkOp struct {
 }
 
 func (o *UnlinkOp) Respond(err error) {
+	defer o.commonOp.opsInFlight.Done()
+
 	if err != nil {
 		o.commonOp.respondErr(err)
 		return
@@ -462,6 +480,8 @@ type OpenDirOp struct {
 }
 
 func (o *OpenDirOp) Respond(err error) {
+	defer o.commonOp.opsInFlight.Done()
+
 	if err != nil {
 		o.commonOp.respondErr(err)
 		return
@@ -566,6 +586,8 @@ type ReadDirOp struct {
 }
 
 func (o *ReadDirOp) Respond(err error) {
+	defer o.commonOp.opsInFlight.Done()
+
 	if err != nil {
 		o.commonOp.respondErr(err)
 		return
@@ -597,6 +619,8 @@ type ReleaseDirHandleOp struct {
 }
 
 func (o *ReleaseDirHandleOp) Respond(err error) {
+	defer o.commonOp.opsInFlight.Done()
+
 	if err != nil {
 		o.commonOp.respondErr(err)
 		return
@@ -636,6 +660,8 @@ type OpenFileOp struct {
 }
 
 func (o *OpenFileOp) Respond(err error) {
+	defer o.commonOp.opsInFlight.Done()
+
 	if err != nil {
 		o.commonOp.respondErr(err)
 		return
@@ -679,6 +705,8 @@ type ReadFileOp struct {
 }
 
 func (o *ReadFileOp) Respond(err error) {
+	defer o.commonOp.opsInFlight.Done()
+
 	if err != nil {
 		o.commonOp.respondErr(err)
 		return
@@ -763,6 +791,8 @@ type WriteFileOp struct {
 }
 
 func (o *WriteFileOp) Respond(err error) {
+	defer o.commonOp.opsInFlight.Done()
+
 	if err != nil {
 		o.commonOp.respondErr(err)
 		return
@@ -801,6 +831,8 @@ type SyncFileOp struct {
 }
 
 func (o *SyncFileOp) Respond(err error) {
+	defer o.commonOp.opsInFlight.Done()
+
 	if err != nil {
 		o.commonOp.respondErr(err)
 		return
@@ -866,6 +898,8 @@ type FlushFileOp struct {
 }
 
 func (o *FlushFileOp) Respond(err error) {
+	defer o.commonOp.opsInFlight.Done()
+
 	if err != nil {
 		o.commonOp.respondErr(err)
 		return
@@ -893,6 +927,8 @@ type ReleaseFileHandleOp struct {
 }
 
 func (o *ReleaseFileHandleOp) Respond(err error) {
+	defer o.commonOp.opsInFlight.Done()
+
 	if err != nil {
 		o.commonOp.respondErr(err)
 		return
diff --git a/mounted_file_system.go b/mounted_file_system.go
index db3e9e1..6772793 100644
--- a/mounted_file_system.go
+++ b/mounted_file_system.go
@@ -44,9 +44,12 @@ func (mfs *MountedFileSystem) Dir() string {
 	return mfs.dir
 }
 
-// Block until a mounted file system has been unmounted. The return value will
-// be non-nil if anything unexpected happened while serving. May be called
-// multiple times.
+// Block until a mounted file system has been unmounted. Do not return
+// successfully until all ops read from the connection have been responded to
+// (i.e. the file system server has finished processing all in-flight ops).
+//
+// The return value will be non-nil if anything unexpected happened while
+// serving. May be called multiple times.
 func (mfs *MountedFileSystem) Join(ctx context.Context) error {
 	select {
 	case <-mfs.joinStatusAvailable:
diff --git a/samples/in_process.go b/samples/in_process.go
index 2fc2ecf..ae78210 100644
--- a/samples/in_process.go
+++ b/samples/in_process.go
@@ -129,5 +129,12 @@ func (t *SampleTest) destroy() (err error) {
 		return
 	}
 
+	// Join the file system.
+	err = t.mfs.Join(t.Ctx)
+	if err != nil {
+		err = fmt.Errorf("mfs.Join: %v", err)
+		return
+	}
+
 	return
 }