Add some basic sanity-check tests for the fat_checksum() function and the fat_time_unix2fat() and fat_time_fat2unix() functions. These unit tests verify these functions return correct output for a number of test inputs.

These tests were inspored by -- and serve a similar purpose to -- the timestamp parsing KUnit tests in ext4[1].

Note that, unlike fat_time_unix2fat, fat_time_fat2unix wasn't previously exported, so this patch exports it as well. This is required for the case where we're building the fat and fat_test as modules.

[1]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/fs/e...

Signed-off-by: David Gow davidgow@google.com Acked-by: OGAWA Hirofumi hirofumi@mail.parknet.co.jp ---

Changes since v6: https://lore.kernel.org/linux-kselftest/20201024060558.2556249-1-davidgow@go... - Make CONFIG_FAT_DEFAULT_CODEPAGE depend on FAT_FS, rather than either VFAT_FS or MSDOS_FS. - This means that FAT_KUNIT_TEST can now also just depend of FAT_FS - Fix a few warnings that KUnit tool was eating: - KUnit's type checking needs a specific cast for the fat_checksum() expected results. - The time test cases shouldn't be 'const' - The fake superblock is now static, as otherwise it increased the stack size too much.

Changes since v4/5: https://lore.kernel.org/linux-kselftest/20201024052047.2526780-1-davidgow@go... - Fix a typo introduced in the Kconfig. It builds now.

Changes since v3: https://lore.kernel.org/linux-kselftest/20201021061713.1545931-1-davidgow@go... - Update the Kconfig entry to use "depends on" rather than "select", as discussed in [2]. - Depend on "MSDOS_FS || VFAT_FS", rather than "FAT_FS", as we need the CONFIG_FAT_DEFAULT_CODEPAGE symbol to be defined.

Changes since v2: https://lore.kernel.org/linux-kselftest/20201020055856.1270482-1-davidgow@go... - Comment that the export for fat_time_fat2unix() function is for KUnit tests.

Changes since v1: https://lore.kernel.org/linux-kselftest/20201017064107.375174-1-davidgow@goo... - Now export fat_time_fat2unix() so that the test can access it when built as a module.

[2]: https://lore.kernel.org/linux-ext4/52959e99-4105-3de9-730c-c46894b82bdd@infr...

fs/fat/Kconfig | 14 +++- fs/fat/Makefile | 2 + fs/fat/fat_test.c | 196 ++++++++++++++++++++++++++++++++++++++++++++++ fs/fat/misc.c | 2 + 4 files changed, 213 insertions(+), 1 deletion(-) create mode 100644 fs/fat/fat_test.c

diff --git a/fs/fat/Kconfig b/fs/fat/Kconfig index 66532a71e8fd..238cc55f84c4 100644 --- a/fs/fat/Kconfig +++ b/fs/fat/Kconfig @@ -77,7 +77,7 @@ config VFAT_FS

config FAT_DEFAULT_CODEPAGE int "Default codepage for FAT" - depends on MSDOS_FS || VFAT_FS + depends on FAT_FS default 437 help This option should be set to the codepage of your FAT filesystems. @@ -115,3 +115,15 @@ config FAT_DEFAULT_UTF8 Say Y if you use UTF-8 encoding for file names, N otherwise.

See file:Documentation/filesystems/vfat.rst for more information. + +config FAT_KUNIT_TEST + tristate "Unit Tests for FAT filesystems" if !KUNIT_ALL_TESTS + depends on KUNIT && FAT_FS + default KUNIT_ALL_TESTS + help + This builds the FAT KUnit tests + + For more information on KUnit and unit tests in general, please refer + to the KUnit documentation in Documentation/dev-tools/kunit + + If unsure, say N diff --git a/fs/fat/Makefile b/fs/fat/Makefile index 70645ce2f7fc..2b034112690d 100644 --- a/fs/fat/Makefile +++ b/fs/fat/Makefile @@ -10,3 +10,5 @@ obj-$(CONFIG_MSDOS_FS) += msdos.o fat-y := cache.o dir.o fatent.o file.o inode.o misc.o nfs.o vfat-y := namei_vfat.o msdos-y := namei_msdos.o + +obj-$(CONFIG_FAT_KUNIT_TEST) += fat_test.o diff --git a/fs/fat/fat_test.c b/fs/fat/fat_test.c new file mode 100644 index 000000000000..7d3fe928fbe6 --- /dev/null +++ b/fs/fat/fat_test.c @@ -0,0 +1,196 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * KUnit tests for FAT filesystems. + * + * Copyright (C) 2020 Google LLC. + * Author: David Gow davidgow@google.com + */ + +#include <kunit/test.h> + +#include "fat.h" + +static void fat_checksum_test(struct kunit *test) +{ + /* With no extension. */ + KUNIT_EXPECT_EQ(test, fat_checksum("VMLINUX "), (u8)44); + /* With 3-letter extension. */ + KUNIT_EXPECT_EQ(test, fat_checksum("README TXT"), (u8)115); + /* With short (1-letter) extension. */ + KUNIT_EXPECT_EQ(test, fat_checksum("ABCDEFGHA "), (u8)98); +} + + +struct fat_timestamp_testcase { + const char *name; + struct timespec64 ts; + __le16 time; + __le16 date; + u8 cs; + int time_offset; +}; + +static struct fat_timestamp_testcase time_test_cases[] = { + { + .name = "Earliest possible UTC (1980-01-01 00:00:00)", + .ts = {.tv_sec = 315532800LL, .tv_nsec = 0L}, + .time = 0, + .date = 33, + .cs = 0, + .time_offset = 0, + }, + { + .name = "Latest possible UTC (2107-12-31 23:59:58)", + .ts = {.tv_sec = 4354819198LL, .tv_nsec = 0L}, + .time = 49021, + .date = 65439, + .cs = 0, + .time_offset = 0, + }, + { + .name = "Earliest possible (UTC-11) (== 1979-12-31 13:00:00 UTC)", + .ts = {.tv_sec = 315493200LL, .tv_nsec = 0L}, + .time = 0, + .date = 33, + .cs = 0, + .time_offset = 11 * 60, + }, + { + .name = "Latest possible (UTC+11) (== 2108-01-01 10:59:58 UTC)", + .ts = {.tv_sec = 4354858798LL, .tv_nsec = 0L}, + .time = 49021, + .date = 65439, + .cs = 0, + .time_offset = -11 * 60, + }, + { + .name = "Leap Day / Year (1996-02-29 00:00:00)", + .ts = {.tv_sec = 825552000LL, .tv_nsec = 0L}, + .time = 0, + .date = 8285, + .cs = 0, + .time_offset = 0, + }, + { + .name = "Year 2000 is leap year (2000-02-29 00:00:00)", + .ts = {.tv_sec = 951782400LL, .tv_nsec = 0L}, + .time = 0, + .date = 10333, + .cs = 0, + .time_offset = 0, + }, + { + .name = "Year 2100 not leap year (2100-03-01 00:00:00)", + .ts = {.tv_sec = 4107542400LL, .tv_nsec = 0L}, + .time = 0, + .date = 61537, + .cs = 0, + .time_offset = 0, + }, + { + .name = "Leap year + timezone UTC+1 (== 2004-02-29 00:30:00 UTC)", + .ts = {.tv_sec = 1078014600LL, .tv_nsec = 0L}, + .time = 48064, + .date = 12380, + .cs = 0, + .time_offset = -60, + }, + { + .name = "Leap year + timezone UTC-1 (== 2004-02-29 23:30:00 UTC)", + .ts = {.tv_sec = 1078097400LL, .tv_nsec = 0L}, + .time = 960, + .date = 12385, + .cs = 0, + .time_offset = 60, + }, + { + .name = "VFAT odd-second resolution (1999-12-31 23:59:59)", + .ts = {.tv_sec = 946684799LL, .tv_nsec = 0L}, + .time = 49021, + .date = 10143, + .cs = 100, + .time_offset = 0, + }, + { + .name = "VFAT 10ms resolution (1980-01-01 00:00:00:0010)", + .ts = {.tv_sec = 315532800LL, .tv_nsec = 10000000L}, + .time = 0, + .date = 33, + .cs = 1, + .time_offset = 0, + }, +}; + +static void fat_time_fat2unix_test(struct kunit *test) +{ + static struct msdos_sb_info fake_sb; + int i; + struct timespec64 ts; + + for (i = 0; i < ARRAY_SIZE(time_test_cases); ++i) { + fake_sb.options.tz_set = 1; + fake_sb.options.time_offset = time_test_cases[i].time_offset; + + fat_time_fat2unix(&fake_sb, &ts, + time_test_cases[i].time, + time_test_cases[i].date, + time_test_cases[i].cs); + KUNIT_EXPECT_EQ_MSG(test, + time_test_cases[i].ts.tv_sec, + ts.tv_sec, + "Timestamp mismatch (seconds) in case "%s"\n", + time_test_cases[i].name); + KUNIT_EXPECT_EQ_MSG(test, + time_test_cases[i].ts.tv_nsec, + ts.tv_nsec, + "Timestamp mismatch (nanoseconds) in case "%s"\n", + time_test_cases[i].name); + } +} + +static void fat_time_unix2fat_test(struct kunit *test) +{ + static struct msdos_sb_info fake_sb; + int i; + __le16 date, time; + u8 cs; + + for (i = 0; i < ARRAY_SIZE(time_test_cases); ++i) { + fake_sb.options.tz_set = 1; + fake_sb.options.time_offset = time_test_cases[i].time_offset; + + fat_time_unix2fat(&fake_sb, &time_test_cases[i].ts, + &time, &date, &cs); + KUNIT_EXPECT_EQ_MSG(test, + time_test_cases[i].time, + time, + "Time mismatch in case "%s"\n", + time_test_cases[i].name); + KUNIT_EXPECT_EQ_MSG(test, + time_test_cases[i].date, + date, + "Date mismatch in case "%s"\n", + time_test_cases[i].name); + KUNIT_EXPECT_EQ_MSG(test, + time_test_cases[i].cs, + cs, + "Centisecond mismatch in case "%s"\n", + time_test_cases[i].name); + } +} + +static struct kunit_case fat_test_cases[] = { + KUNIT_CASE(fat_checksum_test), + KUNIT_CASE(fat_time_fat2unix_test), + KUNIT_CASE(fat_time_unix2fat_test), + {}, +}; + +static struct kunit_suite fat_test_suite = { + .name = "fat_test", + .test_cases = fat_test_cases, +}; + +kunit_test_suites(&fat_test_suite); + +MODULE_LICENSE("GPL v2"); diff --git a/fs/fat/misc.c b/fs/fat/misc.c index f1b2a1fc2a6a..3eabd07b38e2 100644 --- a/fs/fat/misc.c +++ b/fs/fat/misc.c @@ -229,6 +229,8 @@ void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec64 *ts, ts->tv_nsec = 0; } } +/* Export fat_time_fat2unix() for the fat_test KUnit tests. */ +EXPORT_SYMBOL_GPL(fat_time_fat2unix);

/* Convert linear UNIX date to a FAT time/date pair. */ void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec64 *ts,