fusefrontend: print dirCache stats after unmount

internal/fusefrontend/dircache.go

@@ -151,7 +151,16 @@ func (d *dirCache) expireThread() {
 	for {
 		time.Sleep(60 * time.Second)
 		d.Clear()
-		if enableStats {
+		d.stats()
+	}
+}
+
+// stats prints hit rate statistics and resets the counters. No-op if
+// enableStats == false.
+func (d *dirCache) stats() {
+	if !enableStats {
+		return
+	}
 	d.Lock()
 	lookups := d.lookups
 	hits := d.hits
@@ -162,8 +171,6 @@ func (d *dirCache) expireThread() {
 		fmt.Printf("dirCache: hits=%3d lookups=%3d, rate=%3d%%\n", hits, lookups, (hits*100)/lookups)
 	}
 }
-	}
-}
 
 // dbg prints a debug message. Usually disabled.
 func (d *dirCache) dbg(format string, a ...interface{}) {

internal/fusefrontend/root_node.go

@@ -76,6 +76,12 @@ func NewRootNode(args Args, c *contentenc.ContentEnc, n nametransform.NameTransf
 	return rn
 }
 
+// main.doMount() calls this after unmount
+func (rn *RootNode) AfterUnmount() {
+	// print stats before we exit
+	rn.dirCache.stats()
+}
+
 // mangleOpenFlags is used by Create() and Open() to convert the open flags the user
 // wants to the flags we internally use to open the backing file.
 // The returned flags always contain O_NOFOLLOW.

mount.go

@@ -37,6 +37,12 @@ import (
 	"github.com/rfjakob/gocryptfs/internal/tlog"
 )
 
+// AfterUnmount is called after the filesystem has been unmounted.
+// This can be used for cleanup and printing statistics.
+type AfterUnmounter interface {
+	AfterUnmount()
+}
+
 // doMount mounts an encrypted directory.
 // Called from main.
 func doMount(args *argContainer) {
@@ -116,10 +122,13 @@ func doMount(args *argContainer) {
 	tlog.Debug.Printf("cli args: %#v", args)
 	// Initialize gocryptfs (read config file, ask for password, ...)
 	fs, wipeKeys := initFuseFrontend(args)
-	// Initialize go-fuse FUSE server
-	srv := initGoFuse(fs, args)
 	// Try to wipe secret keys from memory after unmount
 	defer wipeKeys()
+	// Initialize go-fuse FUSE server
+	srv := initGoFuse(fs, args)
+	if x, ok := fs.(AfterUnmounter); ok {
+		defer x.AfterUnmount()
+	}
 
 	tlog.Info.Println(tlog.ColorGreen + "Filesystem mounted and ready." + tlog.ColorReset)
 	// We have been forked into the background, as evidenced by the set