diff --git a/src/lib/libsigs.js b/src/lib/libsigs.js
index 4b19dec546636..789cd18459ac1 100644
--- a/src/lib/libsigs.js
+++ b/src/lib/libsigs.js
@@ -439,6 +439,7 @@ sigs = {
   _wasmfs_opfs_set_size_access__sig: 'vpijp',
   _wasmfs_opfs_set_size_file__sig: 'vpijp',
   _wasmfs_opfs_write_access__sig: 'iipij',
+  _wasmfs_opfs_close_all__sig: 'vp',
   _wasmfs_stdin_get_char__sig: 'i',
   _wasmfs_thread_utils_heartbeat__sig: 'vp',
   alBuffer3f__sig: 'viifff',
diff --git a/src/lib/libwasmfs_opfs.js b/src/lib/libwasmfs_opfs.js
index 405891b05d0d6..13cc48e782b03 100644
--- a/src/lib/libwasmfs_opfs.js
+++ b/src/lib/libwasmfs_opfs.js
@@ -474,5 +474,26 @@ addToLibrary({
       {{{ makeSetValue('errPtr', 0, 'err', 'i32') }}};
     }
     wasmfsOPFSProxyFinish(ctx);
-  }
+  },
+
+ _wasmfs_opfs_close_all__deps: ['$wasmfsOPFSAccessHandles', '$wasmfsOPFSProxyFinish'],
+ _wasmfs_opfs_close_all__async: {{{ !PTHREADS }}},
+ _wasmfs_opfs_close_all: async function(ctx) {
+    for (let i = 0; i < wasmfsOPFSAccessHandles.allocated.length; i++)
+    {
+      const handle = wasmfsOPFSAccessHandles.allocated[i];
+      if (handle && handle.close)
+      {
+        try {
+          await handle.close();
+        } catch (e) {
+#if ASSERTIONS
+      err('unexpected error:', e, e.stack);
+#endif
+        }
+        wasmfsOPFSAccessHandles.free(i);
+      }
+    }
+    wasmfsOPFSProxyFinish(ctx);
+ }
 });
diff --git a/system/include/emscripten/wasmfs.h b/system/include/emscripten/wasmfs.h
index f7025dc6eb6cb..9f1c6b8f3aac4 100644
--- a/system/include/emscripten/wasmfs.h
+++ b/system/include/emscripten/wasmfs.h
@@ -91,6 +91,8 @@ backend_t wasmfs_create_node_backend(const char* root __attribute__((nonnull)));
 // thread.
 backend_t wasmfs_create_opfs_backend(void);
 
+void wasmfs_close_opfs_backend(backend_t backend);
+
 // Creates a generic JSIMPL backend
 backend_t wasmfs_create_jsimpl_backend(void);
 
diff --git a/system/lib/wasmfs/backends/opfs_backend.cpp b/system/lib/wasmfs/backends/opfs_backend.cpp
index 6a5be884cc38b..ac5d03544f6e2 100644
--- a/system/lib/wasmfs/backends/opfs_backend.cpp
+++ b/system/lib/wasmfs/backends/opfs_backend.cpp
@@ -393,6 +393,10 @@ class OPFSBackend : public Backend {
     // Symlinks not supported.
     return nullptr;
   }
+
+  void closeAll() {
+    proxy([](auto ctx) { _wasmfs_opfs_close_all(ctx.ctx); });
+  }
 };
 
 } // anonymous namespace
@@ -415,4 +419,10 @@ void EMSCRIPTEN_KEEPALIVE _wasmfs_opfs_record_entry(
   entries->push_back({name, File::FileKind(type), 0});
 }
 
+void wasmfs_close_opfs_backend(backend_t backend) {
+  auto opfsBackend = static_cast<OPFSBackend*>(backend);
+  assert(opfsBackend && "Invalid OPFS backend");
+  opfsBackend->closeAll();
+}
+
 } // extern "C"
diff --git a/system/lib/wasmfs/backends/opfs_backend.h b/system/lib/wasmfs/backends/opfs_backend.h
index fc484bdd067b9..683a25ce2ae75 100644
--- a/system/lib/wasmfs/backends/opfs_backend.h
+++ b/system/lib/wasmfs/backends/opfs_backend.h
@@ -104,4 +104,6 @@ void _wasmfs_opfs_set_size_file(em_proxying_ctx* ctx,
 
 void _wasmfs_opfs_flush_access(em_proxying_ctx* ctx, int access_id, int* err);
 
+void _wasmfs_opfs_close_all(em_proxying_ctx* ctx);
+
 } // extern "C"
diff --git a/test/code_size/audio_worklet_wasm.json b/test/code_size/audio_worklet_wasm.json
index 5aad516bd2316..37e4532c6ea51 100644
--- a/test/code_size/audio_worklet_wasm.json
+++ b/test/code_size/audio_worklet_wasm.json
@@ -3,8 +3,8 @@
   "a.html.gz": 364,
   "a.js": 3853,
   "a.js.gz": 2050,
-  "a.wasm": 1294,
-  "a.wasm.gz": 864,
-  "total": 5666,
+  "a.wasm": 1288,
+  "a.wasm.gz": 867,
+  "total": 5660,
   "total_gz": 3278
 }
diff --git a/test/code_size/embind_hello_wasm.json b/test/code_size/embind_hello_wasm.json
index a9884cc49d60f..e0d0528b85c2d 100644
--- a/test/code_size/embind_hello_wasm.json
+++ b/test/code_size/embind_hello_wasm.json
@@ -3,8 +3,8 @@
   "a.html.gz": 380,
   "a.js": 7266,
   "a.js.gz": 3321,
-  "a.wasm": 7300,
-  "a.wasm.gz": 3348,
-  "total": 15118,
-  "total_gz": 7049
+  "a.wasm": 7294,
+  "a.wasm.gz": 3346,
+  "total": 15112,
+  "total_gz": 7047
 }
diff --git a/test/code_size/hello_wasm_worker_wasm.json b/test/code_size/hello_wasm_worker_wasm.json
index 4b31168c56d25..b5e8b1476b786 100644
--- a/test/code_size/hello_wasm_worker_wasm.json
+++ b/test/code_size/hello_wasm_worker_wasm.json
@@ -3,8 +3,8 @@
   "a.html.gz": 364,
   "a.js": 830,
   "a.js.gz": 530,
-  "a.wasm": 1891,
-  "a.wasm.gz": 1082,
-  "total": 3240,
-  "total_gz": 1976
+  "a.wasm": 1885,
+  "a.wasm.gz": 1079,
+  "total": 3234,
+  "total_gz": 1973
 }
diff --git a/test/code_size/hello_webgl2_wasm.json b/test/code_size/hello_webgl2_wasm.json
index c9afcedc357e2..f45711ef1d80d 100644
--- a/test/code_size/hello_webgl2_wasm.json
+++ b/test/code_size/hello_webgl2_wasm.json
@@ -3,8 +3,8 @@
   "a.html.gz": 328,
   "a.js": 4386,
   "a.js.gz": 2252,
-  "a.wasm": 8286,
-  "a.wasm.gz": 5617,
+  "a.wasm": 8278,
+  "a.wasm.gz": 5627,
   "total": 13126,
   "total_gz": 8197
 }
diff --git a/test/code_size/hello_webgl_wasm.json b/test/code_size/hello_webgl_wasm.json
index 2e1ba8e7f8d09..337555ae0e026 100644
--- a/test/code_size/hello_webgl_wasm.json
+++ b/test/code_size/hello_webgl_wasm.json
@@ -3,8 +3,8 @@
   "a.html.gz": 328,
   "a.js": 3924,
   "a.js.gz": 2092,
-  "a.wasm": 8286,
-  "a.wasm.gz": 5617,
-  "total": 12664,
-  "total_gz": 8037
+  "a.wasm": 8278,
+  "a.wasm.gz": 5627,
+  "total": 12656,
+  "total_gz": 8047
 }
diff --git a/test/code_size/hello_webgl_wasm2js.json b/test/code_size/hello_webgl_wasm2js.json
index 3a2fcd28a1104..f7e13afe1e948 100644
--- a/test/code_size/hello_webgl_wasm2js.json
+++ b/test/code_size/hello_webgl_wasm2js.json
@@ -1,8 +1,8 @@
 {
   "a.html": 346,
   "a.html.gz": 262,
-  "a.js": 17605,
-  "a.js.gz": 9614,
-  "total": 17951,
-  "total_gz": 9876
+  "a.js": 17630,
+  "a.js.gz": 9603,
+  "total": 17976,
+  "total_gz": 9865
 }
diff --git a/test/code_size/math_wasm.json b/test/code_size/math_wasm.json
index 9d06a35db4f41..0baeeb4cb0883 100644
--- a/test/code_size/math_wasm.json
+++ b/test/code_size/math_wasm.json
@@ -3,8 +3,8 @@
   "a.html.gz": 380,
   "a.js": 110,
   "a.js.gz": 125,
-  "a.wasm": 2687,
-  "a.wasm.gz": 1658,
-  "total": 3349,
-  "total_gz": 2163
+  "a.wasm": 2678,
+  "a.wasm.gz": 1655,
+  "total": 3340,
+  "total_gz": 2160
 }
diff --git a/test/other/codesize/test_codesize_hello_O0.size b/test/other/codesize/test_codesize_hello_O0.size
index eec17de1a748f..3b8287d415f3a 100644
--- a/test/other/codesize/test_codesize_hello_O0.size
+++ b/test/other/codesize/test_codesize_hello_O0.size
@@ -1 +1 @@
-15133
+15135
diff --git a/test/other/codesize/test_codesize_hello_O1.size b/test/other/codesize/test_codesize_hello_O1.size
index 6338b1987b648..cbb9ec4e57648 100644
--- a/test/other/codesize/test_codesize_hello_O1.size
+++ b/test/other/codesize/test_codesize_hello_O1.size
@@ -1 +1 @@
-2673
+2675
diff --git a/test/other/codesize/test_codesize_hello_O2.size b/test/other/codesize/test_codesize_hello_O2.size
index 90e525730040d..f48626da3a84f 100644
--- a/test/other/codesize/test_codesize_hello_O2.size
+++ b/test/other/codesize/test_codesize_hello_O2.size
@@ -1 +1 @@
-1977
+1979
diff --git a/test/other/codesize/test_codesize_hello_O3.size b/test/other/codesize/test_codesize_hello_O3.size
index b339887848ea0..b0539e90d9ac1 100644
--- a/test/other/codesize/test_codesize_hello_O3.size
+++ b/test/other/codesize/test_codesize_hello_O3.size
@@ -1 +1 @@
-1733
+1735
diff --git a/test/other/codesize/test_codesize_hello_Os.size b/test/other/codesize/test_codesize_hello_Os.size
index a858d2d47bab2..1c38c9071a6a5 100644
--- a/test/other/codesize/test_codesize_hello_Os.size
+++ b/test/other/codesize/test_codesize_hello_Os.size
@@ -1 +1 @@
-1724
+1725
diff --git a/test/other/codesize/test_codesize_hello_dylink.size b/test/other/codesize/test_codesize_hello_dylink.size
index afd43f8827d5b..dfa51a1359a00 100644
--- a/test/other/codesize/test_codesize_hello_dylink.size
+++ b/test/other/codesize/test_codesize_hello_dylink.size
@@ -1 +1 @@
-18547
+18549
diff --git a/test/other/codesize/test_codesize_hello_single_file.jssize b/test/other/codesize/test_codesize_hello_single_file.jssize
index 8755c7be20a70..4cd877762ac5c 100644
--- a/test/other/codesize/test_codesize_hello_single_file.jssize
+++ b/test/other/codesize/test_codesize_hello_single_file.jssize
@@ -1 +1 @@
-6611
+6615
diff --git a/test/other/codesize/test_codesize_hello_wasmfs.size b/test/other/codesize/test_codesize_hello_wasmfs.size
index b339887848ea0..b0539e90d9ac1 100644
--- a/test/other/codesize/test_codesize_hello_wasmfs.size
+++ b/test/other/codesize/test_codesize_hello_wasmfs.size
@@ -1 +1 @@
-1733
+1735
diff --git a/test/other/test_unoptimized_code_size.wasm.size b/test/other/test_unoptimized_code_size.wasm.size
index eec17de1a748f..3b8287d415f3a 100644
--- a/test/other/test_unoptimized_code_size.wasm.size
+++ b/test/other/test_unoptimized_code_size.wasm.size
@@ -1 +1 @@
-15133
+15135
diff --git a/test/other/test_unoptimized_code_size_strict.wasm.size b/test/other/test_unoptimized_code_size_strict.wasm.size
index eec17de1a748f..3b8287d415f3a 100644
--- a/test/other/test_unoptimized_code_size_strict.wasm.size
+++ b/test/other/test_unoptimized_code_size_strict.wasm.size
@@ -1 +1 @@
-15133
+15135