From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AAACBC001DE for ; Thu, 13 Jul 2023 23:09:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233189AbjGMXJq (ORCPT ); Thu, 13 Jul 2023 19:09:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52950 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229916AbjGMXJq (ORCPT ); Thu, 13 Jul 2023 19:09:46 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1E26B172C; Thu, 13 Jul 2023 16:09:42 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 7CA4B60A70; Thu, 13 Jul 2023 23:09:41 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 992A5C433C8; Thu, 13 Jul 2023 23:09:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1689289780; bh=BQUnTmDBddlxRHvOZ6/VzgVMFh5ycXpIlBQaFHVxBWY=; h=From:To:Cc:Subject:Date:From; b=KO1cxiOL4XiocgTiv66xqzumu2NxX1I7gYuPmaYFGtcI/OoyvzyRE9YhoZd2cTTZW vSY2O7BZlZgyHd3X9Koqjz4D8pIWoda3AQeVnjD7yk4bEQdMZTexHkAoqgBkUwwv/d FqwRmM/FIukX4H1OLAMEWAuxwR9UyFwLigwkWJ46A6357oPWZZztXcj4GSN0cLFtgE PQljHqIkqCobJyQpkXphEfJi2/k/N3Fx2nrAAhnzn0EFajPtXMqKyWo7TMIGMG4CU7 AA0hxtStKSTfQ7MuLFOod9xc97dfFoT0fJdMfj+hi3RAUCvwN2MWnIsOPy8L+iEbDm 546FMXW+pkf1Q== From: Jeff Layton To: fstests@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org Subject: [fstests PATCH] generic: add a test for multigrain timestamps Date: Thu, 13 Jul 2023 19:09:39 -0400 Message-ID: <20230713230939.367068-1-jlayton@kernel.org> X-Mailer: git-send-email 2.41.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Ensure that the mtime and ctime apparently change, even when there are multiple writes in quick succession. Older kernels didn't do this, but there are patches in flight that should help ensure it in the future. Signed-off-by: Jeff Layton --- src/Makefile | 2 +- src/mgctime.c | 107 ++++++++++++++++++++++++++++++++++++++++++ tests/generic/730 | 25 ++++++++++ tests/generic/730.out | 1 + 4 files changed, 134 insertions(+), 1 deletion(-) create mode 100644 src/mgctime.c create mode 100755 tests/generic/730 create mode 100644 tests/generic/730.out This patchset is intended to test the new multigrain timestamp feature: https://lore.kernel.org/linux-fsdevel/20230713-mgctime-v5-0-9eb795d2ae37@kernel.org/T/#t I had originally attempted to write this as a shell script, but it was too slow, which made it falsely pass on unpatched kernels. All current filesystems will fail this, so we may want to wait until we are closer to merging the kernel series. diff --git a/src/Makefile b/src/Makefile index 24cd47479140..aff7d07466f0 100644 --- a/src/Makefile +++ b/src/Makefile @@ -33,7 +33,7 @@ LINUX_TARGETS = xfsctl bstat t_mtab getdevicesize preallo_rw_pattern_reader \ attr_replace_test swapon mkswap t_attr_corruption t_open_tmpfiles \ fscrypt-crypt-util bulkstat_null_ocount splice-test chprojid_fail \ detached_mounts_propagation ext4_resize t_readdir_3 splice2pipe \ - uuid_ioctl + uuid_ioctl mgctime EXTRA_EXECS = dmerror fill2attr fill2fs fill2fs_check scaleread.sh \ btrfs_crc32c_forged_name.py popdir.pl popattr.py diff --git a/src/mgctime.c b/src/mgctime.c new file mode 100644 index 000000000000..38e22a8613ff --- /dev/null +++ b/src/mgctime.c @@ -0,0 +1,107 @@ +/* + * Older Linux kernels always use coarse-grained timestamps, with a + * resolution of around 1 jiffy. Writes that are done in quick succession + * on those kernels apparent change to the ctime or mtime. + * + * Newer kernels attempt to ensure that fine-grained timestamps are used + * when the mtime or ctime are queried from userland. + * + * Open a file and do a 1 byte write to it and then statx the mtime and ctime. + * Do that in a loop 1000 times and ensure that the value is different from + * the last. + * + * Copyright (c) 2023: Jeff Layton + */ +#define _GNU_SOURCE 1 +#include +#include +#include +#include +#include +#include +#include +#include + +#define NUM_WRITES 1000 + +static int64_t statx_ts_cmp(struct statx_timestamp *ts1, struct statx_timestamp *ts2) +{ + int64_t ret = ts2->tv_sec - ts1->tv_sec; + + if (ret) + return ret; + + ret = ts2->tv_nsec; + ret -= ts1->tv_nsec; + + return ret; +} + +int main(int argc, char **argv) +{ + int ret, fd, i; + struct statx stx = { }; + struct statx_timestamp ctime, mtime; + bool verbose = false; + + while ((i = getopt(argc, argv, "v")) != -1) { + switch (i) { + case 'v': + verbose = true; + break; + } + } + + if (argc < 2) { + errno = -EINVAL; + perror("usage"); + } + + fd = open(argv[1], O_WRONLY|O_CREAT|O_TRUNC, 0644); + if (fd < 0) { + perror("open"); + return 1; + } + + ret = statx(fd, "", AT_EMPTY_PATH, STATX_MTIME|STATX_CTIME, &stx); + if (ret < 0) { + perror("stat"); + return 1; + } + + ctime = stx.stx_ctime; + mtime = stx.stx_mtime; + + for (i = 0; i < NUM_WRITES; ++i) { + ssize_t written; + + written = write(fd, "a", 1); + if (written < 0) { + perror("write"); + return 1; + } + + ret = statx(fd, "", AT_EMPTY_PATH, STATX_MTIME|STATX_CTIME, &stx); + if (ret < 0) { + perror("stat"); + return 1; + } + + if (verbose) + printf("%d: %llu.%u\n", i, stx.stx_ctime.tv_sec, stx.stx_ctime.tv_nsec); + + if (!statx_ts_cmp(&ctime, &stx.stx_ctime)) { + printf("Duplicate ctime after write!\n"); + return 1; + } + + if (!statx_ts_cmp(&mtime, &stx.stx_mtime)) { + printf("Duplicate mtime after write!\n"); + return 1; + } + + ctime = stx.stx_ctime; + mtime = stx.stx_mtime; + } + return 0; +} diff --git a/tests/generic/730 b/tests/generic/730 new file mode 100755 index 000000000000..c3f24aeb8534 --- /dev/null +++ b/tests/generic/730 @@ -0,0 +1,25 @@ +#! /bin/bash +# SPDX-License-Identifier: GPL-2.0 +# Copyright (c) 2023, Jeff Layton +# +# FS QA Test No. 730 +# +# Multigrain time test +# +# Open a file, and do 1 byte writes to it, and statx the file for +# the ctime and mtime after each write. Ensure that they have changed +# since the previous write. +# +. ./common/preamble +_begin_fstest auto quick + +# Override the default cleanup function. +_require_test_program mgctime + +testfile="$TEST_DIR/test_mgtime_file.$$" + +$here/src/mgctime $testfile + +# success, all done +status=0 +exit diff --git a/tests/generic/730.out b/tests/generic/730.out new file mode 100644 index 000000000000..5dbea532d60f --- /dev/null +++ b/tests/generic/730.out @@ -0,0 +1 @@ +QA output created by 730 -- 2.41.0