.

fuse/ievicttrace

+#!/usr/bin/env bpftrace
+# ievicttrace - trace from where / how inodes are evicted by Linux kernel
+
+#include <linux/fs.h>
+
+/*
+kprobe:evict {
+	@ievict[kstack] = count();
+}
+
+interval:s:3 {
+	print(@ievict);
+	clear(@ievict);
+}
+*/
+
+kprobe:fuse_evict_inode {
+	$inode = (inode *)arg0;
+	$t = elapsed / 1000;
+	printf("%d.%d EVICT i%d: %s\n", $t/1000000, $t%1000000, $inode->i_ino, kstack);
+}

fuse/test/ievict_test.go.old

+package test
+
+// demonstrate that idir can be evicted/forgotten while its child ifile is active
+
+import (
+	"os"
+	"testing"
+	"time"
+
+	"github.com/hanwen/go-fuse/fuse/nodefs"
+	"github.com/hanwen/go-fuse/internal/testutil"
+
+	"lab.nexedi.com/kirr/go123/exc"
+)
+
+func TestIEvict(t *testing.T) {
+	X := exc.Raiseif
+	dir := testutil.TempDir()
+	defer func() {
+		err := os.Remove(dir); X(err)
+	}()
+
+	// setup a filesystem with / -> A -> B -> file
+	root := nodefs.NewDefaultNode()
+	opts := nodefs.NewOptions() // entry timeout = 1s
+	opts.Debug = testutil.VerboseTest()
+	srv, fsconn, err := nodefs.MountRoot(dir, root, opts); X(err)
+
+
+	Adir := nodefs.NewDefaultNode()
+	Bdir := nodefs.NewDefaultNode()
+	root.Inode().NewChild("A", true, Adir)
+	Adir.Inode().NewChild("B", true, Bdir)
+
+	data0 := "hello world"
+	file := NewDataNode([]byte(data0))
+	Bdir.Inode().NewChild("hello.txt", false, file)
+
+	go srv.Serve()
+	err = srv.WaitMount(); X(err)
+	defer func() {
+		err := srv.Unmount(); X(err)
+	}()
+
+	// open file, this will Lookup A, Lookup B, Lookup file, and open file
+	f, err := os.Open(dir + "/A/B/hello.txt"); X(err)
+	defer func() {
+		println("closed")
+		time.Sleep(5*time.Second)
+		println()
+	}()
+	defer f.Close()
+
+	// sleep 3s: during this time dentry root["A"] should be timed out and invalidated.
+	// the kernel evicts inode for A
+	println()
+	time.Sleep(1*time.Second)
+	//os.Stat(dir + "/A")
+	//st := fsconn.EntryNotify(root.Inode(), "A")
+	//st := fsconn.EntryNotify(Adir.Inode(), "B")
+	//st := fsconn.DeleteNotify(root.Inode(), Adir.Inode(), "A")
+	st := fsconn.DeleteNotify(Bdir.Inode(), file.Inode(), "hello.txt")
+	if !st.Ok() {
+		t.Fatalf("entry_notify: %s", st)
+	}
+	time.Sleep(1*time.Second)
+	println()
+
+	st = fsconn.DeleteNotify(Adir.Inode(), Bdir.Inode(), "B")
+	if !st.Ok() {
+		t.Fatalf("entry_notify: %s", st)
+	}
+
+	time.Sleep(1*time.Second)
+	println()
+
+	// now issue read for file.
+	buf := make([]byte, 1024)
+	_, err = f.Read(buf); X(err)
+
+	time.Sleep(1*time.Second)
+	println()
+
+}