diff --git a/internal/fusefrontend/file_holes.go b/internal/fusefrontend/file_holes.go
index 85792f9..0d28004 100644
--- a/internal/fusefrontend/file_holes.go
+++ b/internal/fusefrontend/file_holes.go
@@ -61,7 +61,7 @@ func (f *File) Lseek(ctx context.Context, off uint64, whence uint32) (uint64, sy
 	cipherOff := f.rootNode.contentEnc.PlainSizeToCipherSize(off)
 	newCipherOff, err := syscall.Seek(f.intFd(), int64(cipherOff), int(whence))
 	if err != nil {
-		return uint64(newCipherOff), fs.ToErrno(err)
+		return 0, fs.ToErrno(err)
 	}
 	newOff := f.contentEnc.CipherSizeToPlainSize(uint64(newCipherOff))
 	return newOff, 0
diff --git a/internal/fusefrontend_reverse/file.go b/internal/fusefrontend_reverse/file.go
index 55f5f80..294872f 100644
--- a/internal/fusefrontend_reverse/file.go
+++ b/internal/fusefrontend_reverse/file.go
@@ -68,3 +68,14 @@ func (f *File) Read(ctx context.Context, buf []byte, ioff int64) (resultData fus
 func (f *File) Release(context.Context) syscall.Errno {
 	return fs.ToErrno(f.fd.Close())
 }
+
+// Lseek - FUSE call.
+func (f *File) Lseek(ctx context.Context, off uint64, whence uint32) (uint64, syscall.Errno) {
+	plainOff := f.contentEnc.CipherSizeToPlainSize(off)
+	newPlainOff, err := syscall.Seek(int(f.fd.Fd()), int64(plainOff), int(whence))
+	if err != nil {
+		return 0, fs.ToErrno(err)
+	}
+	newOff := f.contentEnc.PlainSizeToCipherSize(uint64(newPlainOff))
+	return newOff, 0
+}
diff --git a/internal/fusefrontend_reverse/file_api_check.go b/internal/fusefrontend_reverse/file_api_check.go
index 201f1ea..b7e59d4 100644
--- a/internal/fusefrontend_reverse/file_api_check.go
+++ b/internal/fusefrontend_reverse/file_api_check.go
@@ -7,22 +7,19 @@ import (
 // Check that we have implemented the fs.File* interfaces
 var _ = (fs.FileReader)((*File)(nil))
 var _ = (fs.FileReleaser)((*File)(nil))
-
-/* TODO
-var _ = (fs.FileLseeker)((*File2)(nil))
-*/
+var _ = (fs.FileLseeker)((*File)(nil))
 
 /* Not needed
-var _ = (fs.FileGetattrer)((*File2)(nil))
-var _ = (fs.FileGetlker)((*File2)(nil))
-var _ = (fs.FileSetlker)((*File2)(nil))
-var _ = (fs.FileSetlkwer)((*File2)(nil))
+var _ = (fs.FileGetattrer)((*File)(nil))
+var _ = (fs.FileGetlker)((*File)(nil))
+var _ = (fs.FileSetlker)((*File)(nil))
+var _ = (fs.FileSetlkwer)((*File)(nil))
 */
 
 /* Will not implement these - reverse mode is read-only!
-var _ = (fs.FileSetattrer)((*File2)(nil))
-var _ = (fs.FileWriter)((*File2)(nil))
-var _ = (fs.FileFsyncer)((*File2)(nil))
-var _ = (fs.FileFlusher)((*File2)(nil))
-var _ = (fs.FileAllocater)((*File2)(nil))
+var _ = (fs.FileSetattrer)((*File)(nil))
+var _ = (fs.FileWriter)((*File)(nil))
+var _ = (fs.FileFsyncer)((*File)(nil))
+var _ = (fs.FileFlusher)((*File)(nil))
+var _ = (fs.FileAllocater)((*File)(nil))
 */
diff --git a/tests/defaults/main_test.go b/tests/defaults/main_test.go
index 1982c90..8873f8f 100644
--- a/tests/defaults/main_test.go
+++ b/tests/defaults/main_test.go
@@ -263,6 +263,7 @@ func TestCpWarnings(t *testing.T) {
 	}
 }
 
+// TestSeekData tests that fs.FileLseeker is implemented
 func TestSeekData(t *testing.T) {
 	fn := filepath.Join(test_helpers.DefaultPlainDir, t.Name())
 	f, err := os.Create(fn)
diff --git a/tests/reverse/correctness_test.go b/tests/reverse/correctness_test.go
index 78c9c4b..9d7a1c8 100644
--- a/tests/reverse/correctness_test.go
+++ b/tests/reverse/correctness_test.go
@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"io/ioutil"
 	"os"
+	"path/filepath"
 	"syscall"
 	"testing"
 
@@ -257,3 +258,40 @@ func TestStatfs(t *testing.T) {
 		t.Errorf("statfs reports size zero: %#v", st)
 	}
 }
+
+// TestSeekData tests that fs.FileLseeker is implemented
+func TestSeekData(t *testing.T) {
+	if !plaintextnames {
+		t.Skip()
+	}
+
+	fn := filepath.Join(dirA, t.Name())
+	f, err := os.Create(fn)
+	if err != nil {
+		t.Fatal(err)
+	}
+	var oneTiB int64 = 1024 * 1024 * 1024 * 1024
+	if _, err = f.Seek(oneTiB, 0); err != nil {
+		t.Fatal(err)
+	}
+	if _, err = f.Write([]byte("foo")); err != nil {
+		t.Fatal(err)
+	}
+	f.Close()
+
+	const SEEK_DATA = 3
+
+	fn2 := filepath.Join(dirB, t.Name())
+	f, err = os.Open(fn2)
+	if err != nil {
+		t.Fatal(err)
+	}
+	off, err := f.Seek(1024*1024, SEEK_DATA)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if off < oneTiB-1024*1024 {
+		t.Errorf("off=%d, expected=%d\n", off, oneTiB)
+	}
+	f.Close()
+}