Nonsense UNKNOWN error when writing large buffers with fs.writev

Version

14.18.1

Platform

Linux ops 5.11.0-1021-gcp #23~20.04.1-Ubuntu SMP Fri Oct 1 19:04:32 UTC 2021 x86_64 x86_64 x86_64 GNU/Linu

Subsystem

fs

What steps will reproduce the bug?

const fs = require("fs");
const fd = fs.openSync("./test.dat", fs.constants.O_WRONLY | fs.constants.O_CREAT, 0o666);
const bufs = [Buffer.alloc(0x7FFFFFFF + 1)];
fs.writevSync(fd, bufs, 0);

This throws

Uncaught Error: UNKNOWN: unknown error, write
    at Object.writevSync (fs.js:749:3) {
  errno: -2147483648,
  syscall: 'write',
  code: 'UNKNOWN'
}

That errno is 0x7fffffff + 1 wrapped around.

How often does it reproduce? Is there a required condition?

Always.

What is the expected behavior?

Should either work, since pwritev(2) works (I don't know if it has a limit less than SSIZE_MAX), or report a proper error before making the syscall. I did the latter recently for fs.write in c4e7dca8f30ff89b42e96fb8819558ed518a72dd. It would be nice if large files actually worked, but the best fix for that would require a new libuv function.

What do you see instead?

No response

Additional information

No response

Commencez par fs.writevSync dans fs.js et comparez la gestion de ses arguments avec la validation de fs.write référencée par le commit c4e7dca8f30ff89b42e96fb8819558ed518a72dd. Reproduisez le cas du grand buffer sous Linux, puis déterminez si le comportement final doit rejeter la requête avec une erreur appropriée avant le syscall ou prendre en charge le buffer plus grand via libuv.