[v14.x backport] fs: improve fsPromises writeFile performance

lib/internal/fs/promises.js

@@ -1,7 +1,5 @@
 'use strict';
 
-const kWriteFileMaxChunkSize = 2 ** 14;
-
 const {
   ArrayPrototypePush,
   Error,
@@ -40,6 +38,7 @@ const {
     kMaxUserId,
     kReadFileBufferLength,
     kReadFileUnknownBufferLength,
+    kWriteFileMaxChunkSize,
   },
   copyObject,
   getDirents,

lib/internal/fs/utils.js

@@ -126,6 +126,8 @@ const kIoMaxLength = 2 ** 31 - 1;
 const kReadFileUnknownBufferLength = 64 * 1024;
 const kReadFileBufferLength = 512 * 1024;
 
+const kWriteFileMaxChunkSize = 512 * 1024;
+
 const kMaxUserId = 2 ** 32 - 1;
 
 const isWindows = process.platform === 'win32';
@@ -835,6 +837,7 @@ module.exports = {
     kMaxUserId,
     kReadFileBufferLength,
     kReadFileUnknownBufferLength,
+    kWriteFileMaxChunkSize,
   },
   assertEncoding,
   BigIntStats,  // for testing

test/parallel/test-fs-promises-file-handle-writeFile.js

@@ -34,13 +34,17 @@ async function validateWriteFile() {
 async function doWriteAndCancel() {
   const filePathForHandle = path.resolve(tmpDir, 'dogs-running.txt');
   const fileHandle = await open(filePathForHandle, 'w+');
-  const buffer = Buffer.from('dogs running'.repeat(10000), 'utf8');
-  const controller = new AbortController();
-  const { signal } = controller;
-  process.nextTick(() => controller.abort());
-  await assert.rejects(writeFile(fileHandle, buffer, { signal }), {
-    name: 'AbortError'
-  });
+  try {
+    const buffer = Buffer.from('dogs running'.repeat(512 * 1024), 'utf8');
+    const controller = new AbortController();
+    const { signal } = controller;
+    process.nextTick(() => controller.abort());
+    await assert.rejects(writeFile(fileHandle, buffer, { signal }), {
+      name: 'AbortError'
+    });
+  } finally {
+    await fileHandle.close();
+  }
 }
 
 const dest = path.resolve(tmpDir, 'tmp.txt');