From f403537a3489f5e3007f8489cd38c7b4f02af324 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fatih=20G=C3=BCzel?= <fatihguzeldev@gmail.com>
Date: Fri, 6 Nov 2026 18:23:48 +0300
Subject: [PATCH] src: check mtime seconds for file-backed blobs
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compare the seconds part of mtime as well as nanoseconds. otherwise,
same-size edits can go unnoticed on filesystems with coarse timestamps.

add regression coverage for both file-backed blob apis.

Fixes: https://github.com/nodejs/node/issues/67283
Signed-off-by: Fatih Güzel <fatihguzeldev@gmail.com>
---
 src/dataqueue/queue.cc                       |  1 +
 test/parallel/test-blob-file-backed-mtime.js | 36 ++++++++++++++++++++
 2 files changed, 37 insertions(+)
 create mode 100644 test/parallel/test-blob-file-backed-mtime.js

diff --git a/src/dataqueue/queue.cc b/src/dataqueue/queue.cc
index 96a7956b8749..30df8bdf71f6 100644
--- a/src/dataqueue/queue.cc
+++ b/src/dataqueue/queue.cc
@@ -936,6 +936,7 @@ class FdEntry final : public EntryImpl {
 
   bool is_modified(const uv_stat_t& other) {
     return other.st_size != stat_.st_size ||
+           other.st_mtim.tv_sec != stat_.st_mtim.tv_sec ||
            other.st_mtim.tv_nsec != stat_.st_mtim.tv_nsec;
   }
 
diff --git a/test/parallel/test-blob-file-backed-mtime.js b/test/parallel/test-blob-file-backed-mtime.js
new file mode 100644
index 000000000000..1fb12e890382
--- /dev/null
+++ b/test/parallel/test-blob-file-backed-mtime.js
@@ -0,0 +1,36 @@
+'use strict';
+
+require('../common');
+const assert = require('node:assert');
+const { test } = require('node:test');
+const {
+  openAsBlob,
+  openAsBlobSync,
+  statSync,
+  utimesSync,
+  writeFileSync,
+} = require('node:fs');
+const tmpdir = require('../common/tmpdir');
+
+tmpdir.refresh();
+
+for (const openBlob of [openAsBlob, openAsBlobSync]) {
+  test(`${openBlob.name} detects whole-second mtime changes`, async () => {
+    const file = tmpdir.resolve(openBlob.name);
+    const time = 1_700_000_000;
+    writeFileSync(file, 'before');
+    utimesSync(file, time, time);
+    const before = statSync(file, { bigint: true });
+
+    const blob = await openBlob(file);
+    assert.strictEqual(await blob.text(), 'before');
+
+    writeFileSync(file, 'after!');
+    utimesSync(file, time, time + 2);
+    const after = statSync(file, { bigint: true });
+    assert.strictEqual(after.size, before.size);
+    assert.strictEqual(after.mtimeNs - before.mtimeNs, 2_000_000_000n);
+
+    await assert.rejects(blob.text(), { name: 'NotReadableError' });
+  });
+}