Moved in-flight waiting from Connection into Server.

For #9.

connection.go

@@ -43,7 +43,6 @@ type Connection struct {
 	debugLogger *log.Logger
 	errorLogger *log.Logger
 	wrapped     *bazilfuse.Conn
-	opsInFlight sync.WaitGroup
 
 	// The context from which all op contexts inherit.
 	parentCtx context.Context
@@ -217,9 +216,6 @@ func (c *Connection) beginOp(
 	bfReq bazilfuse.Request) (ctx context.Context) {
 	reqID := bfReq.Hdr().ID
 
-	// Note that the op is in flight.
-	c.opsInFlight.Add(1)
-
 	// Choose a parent context.
 	ctx = c.maybeTraceByPID(int(bfReq.Hdr().Pid))
 
@@ -267,9 +263,6 @@ func (c *Connection) finishOp(bfReq bazilfuse.Request) {
 		cancel()
 		delete(c.cancelFuncs, reqID)
 	}
-
-	// Decrement the in-flight counter.
-	c.opsInFlight.Done()
 }
 
 // LOCKS_EXCLUDED(c.mu)
@@ -365,9 +358,9 @@ func (c *Connection) waitForReady() (err error) {
 	return
 }
 
-// Close the connection and wait for in-flight ops.
+// Close the connection. Must not be called until operations that were read
+// from the connection have been responded to.
 func (c *Connection) close() (err error) {
 	err = c.wrapped.Close()
-	c.opsInFlight.Wait()
 	return
 }

fuseutil/file_system.go

@@ -18,6 +18,7 @@ import (
 	"flag"
 	"io"
 	"math/rand"
+	"sync"
 	"time"
 
 	"github.com/jacobsa/fuse"
@@ -73,14 +74,19 @@ type FileSystem interface {
 // cf. http://goo.gl/jnkHPO, fuse-devel thread "Fuse guarantees on concurrent
 // requests").
 func NewFileSystemServer(fs FileSystem) fuse.Server {
-	return fileSystemServer{fs}
+	return &fileSystemServer{
+		fs: fs,
+	}
 }
 
 type fileSystemServer struct {
-	fs FileSystem
+	fs          FileSystem
+	opsInFlight sync.WaitGroup
 }
 
-func (s fileSystemServer) ServeOps(c *fuse.Connection) {
+func (s *fileSystemServer) ServeOps(c *fuse.Connection) {
+	defer s.opsInFlight.Wait()
+
 	for {
 		op, err := c.ReadOp()
 		if err == io.EOF {
@@ -91,11 +97,14 @@ func (s fileSystemServer) ServeOps(c *fuse.Connection) {
 			panic(err)
 		}
 
+		s.opsInFlight.Add(1)
 		go s.handleOp(op)
 	}
 }
 
-func (s fileSystemServer) handleOp(op fuseops.Op) {
+func (s *fileSystemServer) handleOp(op fuseops.Op) {
+	defer s.opsInFlight.Done()
+
 	// Delay if requested.
 	if *fRandomDelays {
 		const delayLimit = 100 * time.Microsecond

mounted_file_system.go

@@ -26,7 +26,8 @@ import (
 
 // A type that knows how to serve ops read from a connection.
 type Server interface {
-	// Read and serve ops from the supplied connection until EOF.
+	// Read and serve ops from the supplied connection until EOF. Do not return
+	// until all operations have been responded to.
 	ServeOps(*Connection)
 }