added fix and test to tail issue

tail_test.go

@@ -435,6 +435,28 @@ func reSeek(t *testing.T, poll bool) {
 	tailTest.Cleanup(tail, false)
 }
 
+func TestPermissionChange(t *testing.T) {
+	tailTest := NewTailTest("change-permission", t)
+	tailTest.CreateFile("test.txt", "a really long string goes here\nhello\nworld\n")
+
+	tail := tailTest.StartTail(
+		"test.txt",
+		Config{Follow: true, ReOpen: true, Poll: false})
+
+	<-time.After(100 * time.Millisecond)
+
+	content := []string{"a really long string goes here", "hello", "world"}
+	go tailTest.VerifyTailOutput(tail, content, false)
+
+	tailTest.ChangeFilePermssions("test.txt", 0200)
+
+	<-time.After(100 * time.Millisecond)
+
+	tailTest.ChangeFilePermssions("test.txt", 0600)
+
+	tailTest.Cleanup(tail, true)
+}
+
 // Test library
 
 type TailTest struct {
@@ -484,6 +506,14 @@ func (t TailTest) RenameFile(oldname string, newname string) {
 	}
 }
 
+func (t TailTest) ChangeFilePermssions(name string, mode os.FileMode) {
+	fPath := t.path + "/" + name
+	err := os.Chmod(fPath, mode)
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
 func (t TailTest) AppendFile(name string, contents string) {
 	f, err := os.OpenFile(t.path+"/"+name, os.O_APPEND|os.O_WRONLY, 0600)
 	if err != nil {

watch/inotify.go

@@ -116,6 +116,12 @@ func (fw *InotifyFileWatcher) ChangeEvents(t *tomb.Tomb, pos int64) (*FileChange
 						changes.NotifyDeleted()
 						return
 					}
+
+					if os.IsPermission(err) {
+						util.LOGGER.Printf("Permission error on file %v: %v\n", fw.Filename, err)
+						continue
+					}
+
 					// XXX: report this error back to the user
 					util.Fatal("Failed to stat file %v: %v", fw.Filename, err)
 				}