diff --git a/cephfs/errors.go b/cephfs/errors.go
index ab28f09..5643499 100644
--- a/cephfs/errors.go
+++ b/cephfs/errors.go
@@ -37,6 +37,9 @@ var (
 	ErrNotConnected = getError(-C.ENOTCONN)
 	// ErrNotExist indicates a non-specific missing resource.
 	ErrNotExist = getError(-C.ENOENT)
+	// ErrOpNotSupported is returned in general for operations that are not
+	// supported.
+	ErrOpNotSupported = getError(-C.EOPNOTSUPP)
 
 	// Private errors:
 
diff --git a/cephfs/file_fallocate_mode_zero_unsupported_test.go b/cephfs/file_fallocate_mode_zero_unsupported_test.go
new file mode 100644
index 0000000..8071d30
--- /dev/null
+++ b/cephfs/file_fallocate_mode_zero_unsupported_test.go
@@ -0,0 +1,30 @@
+//go:build main
+
+package cephfs
+
+import (
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+// TestFallocateModeZeroUnsupported and this test file exists merely to track
+// the backports for https://tracker.ceph.com/issues/68026. Once they are
+// available with release versions this can probably vanish.
+func TestFallocateModeZeroUnsupported(t *testing.T) {
+	mount := fsConnect(t)
+	defer fsDisconnect(t, mount)
+	fname := "file1.txt"
+	f, err := mount.Open(fname, os.O_RDWR|os.O_CREATE, 0644)
+	assert.NoError(t, err)
+	assert.NotNil(t, f)
+	defer func() {
+		assert.NoError(t, f.Close())
+		assert.NoError(t, mount.Unlink(fname))
+	}()
+
+	err = f.Fallocate(FallocNoFlag, 0, 10)
+	assert.Error(t, err)
+	assert.Equal(t, ErrOpNotSupported, err)
+}