op-program: Recreate preimage data dir if required

op-program/host/kvstore/disk.go

@@ -37,7 +37,7 @@ func (d *DiskKV) pathKey(k common.Hash) string {
 func (d *DiskKV) Put(k common.Hash, v []byte) error {
 	d.Lock()
 	defer d.Unlock()
-	f, err := os.CreateTemp(d.path, k.String()+".txt.*")
+	f, err := openTempFile(d.path, k.String()+".txt.*")
 	if err != nil {
 		return fmt.Errorf("failed to open temp file for pre-image %s: %w", k, err)
 	}
@@ -57,6 +57,21 @@ func (d *DiskKV) Put(k common.Hash, v []byte) error {
 	return nil
 }
 
+func openTempFile(dir string, nameTemplate string) (*os.File, error) {
+	f, err := os.CreateTemp(dir, nameTemplate)
+	// Directory has been deleted out from underneath us. Recreate it.
+	if errors.Is(err, os.ErrNotExist) {
+		if mkdirErr := os.MkdirAll(dir, 0777); mkdirErr != nil {
+			return nil, errors.Join(fmt.Errorf("failed to create directory %v: %w", dir, mkdirErr), err)
+		}
+		f, err = os.CreateTemp(dir, nameTemplate)
+	}
+	if err != nil {
+		return nil, err
+	}
+	return f, nil
+}
+
 func (d *DiskKV) Get(k common.Hash) ([]byte, error) {
 	d.RLock()
 	defer d.RUnlock()

op-program/host/kvstore/disk_test.go

 package kvstore
 
-import "testing"
+import (
+	"path/filepath"
+	"testing"
+
+	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/stretchr/testify/require"
+)
 
 func TestDiskKV(t *testing.T) {
 	tmp := t.TempDir() // automatically removed by testing cleanup
 	kv := NewDiskKV(tmp)
 	kvTest(t, kv)
 }
+
+func TestCreateMissingDirectory(t *testing.T) {
+	tmp := t.TempDir()
+	dir := filepath.Join(tmp, "data")
+	kv := NewDiskKV(dir)
+	val := []byte{1, 2, 3, 4}
+	key := crypto.Keccak256Hash(val)
+	require.NoError(t, kv.Put(key, val))
+}