From: avivdaum Date: Sun, 15 Mar 2026 22:24:04 +0000 (+0200) Subject: fat: add KUnit tests for timestamp conversion helpers X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=4bbf3f58e00f8671eb384c7df6983d803058b204;p=thirdparty%2Fkernel%2Flinux.git fat: add KUnit tests for timestamp conversion helpers Extend fat_test with coverage for FAT timestamp edge cases that are not currently exercised. Add tests for fat_time_unix2fat() clamping at the UTC boundaries and when time_offset pushes an otherwise valid timestamp outside the FAT date range. Also cover the NULL time_cs path used by existing callers, and verify fat_truncate_atime() truncation across timezone offsets. Link: https://patch.msgid.link/20260315222404.9678-1-aviv.daum@gmail.com Acked-by: OGAWA Hirofumi Signed-off-by: avivdaum Signed-off-by: Christian Brauner --- diff --git a/fs/fat/fat_test.c b/fs/fat/fat_test.c index 1f00626590675..5c97a7fcc41d0 100644 --- a/fs/fat/fat_test.c +++ b/fs/fat/fat_test.c @@ -29,6 +29,22 @@ struct fat_timestamp_testcase { int time_offset; }; +struct fat_unix2fat_clamp_testcase { + const char *name; + struct timespec64 ts; + __le16 time; + __le16 date; + u8 cs; + int time_offset; +}; + +struct fat_truncate_atime_testcase { + const char *name; + struct timespec64 ts; + struct timespec64 expected; + int time_offset; +}; + static struct fat_timestamp_testcase time_test_cases[] = { { .name = "Earliest possible UTC (1980-01-01 00:00:00)", @@ -120,13 +136,92 @@ static struct fat_timestamp_testcase time_test_cases[] = { }, }; +static struct fat_unix2fat_clamp_testcase unix2fat_clamp_test_cases[] = { + { + .name = "Clamp to earliest FAT date for 1979-12-31 23:59:59 UTC", + .ts = {.tv_sec = 315532799LL, .tv_nsec = 0L}, + .time = cpu_to_le16(0), + .date = cpu_to_le16(33), + .cs = 0, + .time_offset = 0, + }, + { + .name = "Clamp after time_offset=-60 pushes 1980-01-01 00:30 UTC below 1980", + .ts = {.tv_sec = 315534600LL, .tv_nsec = 0L}, + .time = cpu_to_le16(0), + .date = cpu_to_le16(33), + .cs = 0, + .time_offset = -60, + }, + { + .name = "Clamp to latest FAT date for 2108-01-01 00:00:00 UTC", + .ts = {.tv_sec = 4354819200LL, .tv_nsec = 0L}, + .time = cpu_to_le16(49021), + .date = cpu_to_le16(65439), + .cs = 199, + .time_offset = 0, + }, + { + .name = "Clamp after time_offset=60 pushes 2107-12-31 23:30 UTC beyond 2107", + .ts = {.tv_sec = 4354817400LL, .tv_nsec = 0L}, + .time = cpu_to_le16(49021), + .date = cpu_to_le16(65439), + .cs = 199, + .time_offset = 60, + }, +}; + +static struct fat_truncate_atime_testcase truncate_atime_test_cases[] = { + { + .name = "UTC atime truncates to 2004-02-29 00:00:00", + .ts = {.tv_sec = 1078058096LL, .tv_nsec = 789000000L}, + .expected = {.tv_sec = 1078012800LL, .tv_nsec = 0L}, + .time_offset = 0, + }, + { + .name = "time_offset=-60 truncates 2004-02-29 00:30 UTC to previous local midnight", + .ts = {.tv_sec = 1078014645LL, .tv_nsec = 123000000L}, + .expected = {.tv_sec = 1077930000LL, .tv_nsec = 0L}, + .time_offset = -60, + }, + { + .name = "time_offset=60 truncates 2004-02-29 23:30 UTC to next local midnight", + .ts = {.tv_sec = 1078097445LL, .tv_nsec = 123000000L}, + .expected = {.tv_sec = 1078095600LL, .tv_nsec = 0L}, + .time_offset = 60, + }, +}; + static void time_testcase_desc(struct fat_timestamp_testcase *t, char *desc) { strscpy(desc, t->name, KUNIT_PARAM_DESC_SIZE); } +static void unix2fat_clamp_testcase_desc(struct fat_unix2fat_clamp_testcase *t, + char *desc) +{ + strscpy(desc, t->name, KUNIT_PARAM_DESC_SIZE); +} + +static void truncate_atime_testcase_desc(struct fat_truncate_atime_testcase *t, + char *desc) +{ + strscpy(desc, t->name, KUNIT_PARAM_DESC_SIZE); +} + KUNIT_ARRAY_PARAM(fat_time, time_test_cases, time_testcase_desc); +KUNIT_ARRAY_PARAM(fat_unix2fat_clamp, unix2fat_clamp_test_cases, + unix2fat_clamp_testcase_desc); +KUNIT_ARRAY_PARAM(fat_truncate_atime, truncate_atime_test_cases, + truncate_atime_testcase_desc); + +static void fat_test_set_time_offset(struct msdos_sb_info *sbi, int time_offset) +{ + *sbi = (struct msdos_sb_info){}; + sbi->options.tz_set = 1; + sbi->options.time_offset = time_offset; +} static void fat_time_fat2unix_test(struct kunit *test) { @@ -135,8 +230,7 @@ static void fat_time_fat2unix_test(struct kunit *test) struct fat_timestamp_testcase *testcase = (struct fat_timestamp_testcase *)test->param_value; - fake_sb.options.tz_set = 1; - fake_sb.options.time_offset = testcase->time_offset; + fat_test_set_time_offset(&fake_sb, testcase->time_offset); fat_time_fat2unix(&fake_sb, &ts, testcase->time, @@ -160,18 +254,17 @@ static void fat_time_unix2fat_test(struct kunit *test) struct fat_timestamp_testcase *testcase = (struct fat_timestamp_testcase *)test->param_value; - fake_sb.options.tz_set = 1; - fake_sb.options.time_offset = testcase->time_offset; + fat_test_set_time_offset(&fake_sb, testcase->time_offset); fat_time_unix2fat(&fake_sb, &testcase->ts, &time, &date, &cs); KUNIT_EXPECT_EQ_MSG(test, - le16_to_cpu(testcase->time), - le16_to_cpu(time), + testcase->time, + time, "Time mismatch\n"); KUNIT_EXPECT_EQ_MSG(test, - le16_to_cpu(testcase->date), - le16_to_cpu(date), + testcase->date, + date, "Date mismatch\n"); KUNIT_EXPECT_EQ_MSG(test, testcase->cs, @@ -179,10 +272,82 @@ static void fat_time_unix2fat_test(struct kunit *test) "Centisecond mismatch\n"); } +static void fat_time_unix2fat_clamp_test(struct kunit *test) +{ + static struct msdos_sb_info fake_sb; + __le16 date, time; + u8 cs; + struct fat_unix2fat_clamp_testcase *testcase = + (struct fat_unix2fat_clamp_testcase *)test->param_value; + + fat_test_set_time_offset(&fake_sb, testcase->time_offset); + + fat_time_unix2fat(&fake_sb, &testcase->ts, &time, &date, &cs); + KUNIT_EXPECT_EQ_MSG(test, + testcase->time, + time, + "Clamped time mismatch\n"); + KUNIT_EXPECT_EQ_MSG(test, + testcase->date, + date, + "Clamped date mismatch\n"); + KUNIT_EXPECT_EQ_MSG(test, + testcase->cs, + cs, + "Clamped centisecond mismatch\n"); +} + +static void fat_time_unix2fat_no_csec_test(struct kunit *test) +{ + static struct msdos_sb_info fake_sb; + struct timespec64 ts = { + .tv_sec = 946684799LL, + .tv_nsec = 0L, + }; + __le16 date, time; + + fat_test_set_time_offset(&fake_sb, 0); + + fat_time_unix2fat(&fake_sb, &ts, &time, &date, NULL); + KUNIT_EXPECT_EQ_MSG(test, + 49021, + le16_to_cpu(time), + "Time mismatch without centiseconds\n"); + KUNIT_EXPECT_EQ_MSG(test, + 10143, + le16_to_cpu(date), + "Date mismatch without centiseconds\n"); +} + +static void fat_truncate_atime_test(struct kunit *test) +{ + static struct msdos_sb_info fake_sb; + struct timespec64 actual; + struct fat_truncate_atime_testcase *testcase = + (struct fat_truncate_atime_testcase *)test->param_value; + + fat_test_set_time_offset(&fake_sb, testcase->time_offset); + + actual = fat_truncate_atime(&fake_sb, &testcase->ts); + KUNIT_EXPECT_EQ_MSG(test, + testcase->expected.tv_sec, + actual.tv_sec, + "Atime truncation seconds mismatch\n"); + KUNIT_EXPECT_EQ_MSG(test, + testcase->expected.tv_nsec, + actual.tv_nsec, + "Atime truncation nanoseconds mismatch\n"); +} + static struct kunit_case fat_test_cases[] = { KUNIT_CASE(fat_checksum_test), KUNIT_CASE_PARAM(fat_time_fat2unix_test, fat_time_gen_params), KUNIT_CASE_PARAM(fat_time_unix2fat_test, fat_time_gen_params), + KUNIT_CASE_PARAM(fat_time_unix2fat_clamp_test, + fat_unix2fat_clamp_gen_params), + KUNIT_CASE(fat_time_unix2fat_no_csec_test), + KUNIT_CASE_PARAM(fat_truncate_atime_test, + fat_truncate_atime_gen_params), {}, }; diff --git a/fs/fat/misc.c b/fs/fat/misc.c index b154a51627645..3027ef53af214 100644 --- a/fs/fat/misc.c +++ b/fs/fat/misc.c @@ -297,6 +297,8 @@ struct timespec64 fat_truncate_atime(const struct msdos_sb_info *sbi, return (struct timespec64){ seconds, 0 }; } +/* Export fat_truncate_atime() for the fat_test KUnit tests. */ +EXPORT_SYMBOL_GPL(fat_truncate_atime); /* * Update the in-inode atime and/or mtime after truncating the timestamp to the