fusefrontend: print dirCache stats after unmount

internal/fusefrontend/dircache.go

@@ -151,17 +151,24 @@ func (d *dirCache) expireThread() {
 	for {
 		time.Sleep(60 * time.Second)
 		d.Clear()
-		if enableStats {
-			d.Lock()
-			lookups := d.lookups
-			hits := d.hits
-			d.lookups = 0
-			d.hits = 0
-			d.Unlock()
-			if lookups > 0 {
-				fmt.Printf("dirCache: hits=%3d lookups=%3d, rate=%3d%%\n", hits, lookups, (hits*100)/lookups)
-			}
-		}
+		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
+	d.lookups = 0
+	d.hits = 0
+	d.Unlock()
+	if lookups > 0 {
+		fmt.Printf("dirCache: hits=%3d lookups=%3d, rate=%3d%%\n", hits, lookups, (hits*100)/lookups)
 	}
 }
 

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