Re: [PATCH] kunit: fat: test cluster and directory i_pos layout helpers

OGAWA Hirofumi
2026-04-05T05:18:27Z

Adi Nata <adinata.softwareengineer@gmail.com> writes:

> Add KUnit coverage for fat_clus_to_blknr() and fat_get_blknr_offset()
> using stub msdos_sb_info values so cluster-to-sector and i_pos split
> math stays correct.
>
> Signed-off-by: Adi Nata <adinata.softwareengineer@gmail.com>

Looks good.

Acked-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>

Thanks.

> ---
> fs/fat/fat_test.c | 33 +++++++++++++++++++++++++++++++++
> 1 file changed, 33 insertions(+)
>
> diff --git a/fs/fat/fat_test.c b/fs/fat/fat_test.c
> index 1f0062659067..add44178f28e 100644
> --- a/fs/fat/fat_test.c
> +++ b/fs/fat/fat_test.c
> @@ -20,6 +20,37 @@ static void fat_checksum_test(struct kunit *test)
> KUNIT_EXPECT_EQ(test, fat_checksum("ABCDEFGHA "), (u8)98);
> }
>
> +static void fat_clus_to_blknr_test(struct kunit *test)
> +{
> + struct msdos_sb_info sbi = {
> + .sec_per_clus = 4,
> + .data_start = 100,
> + };
> +
> + KUNIT_EXPECT_EQ(test, (sector_t)100,
> + fat_clus_to_blknr(&sbi, FAT_START_ENT));
> + KUNIT_EXPECT_EQ(test, (sector_t)112, fat_clus_to_blknr(&sbi, 5));
> +}
> +
> +static void fat_get_blknr_offset_test(struct kunit *test)
> +{
> + struct msdos_sb_info sbi = {
> + .dir_per_block = 16,
> + .dir_per_block_bits = 4,
> + };
> +
> + sector_t blknr;
> + int offset;
> +
> + fat_get_blknr_offset(&sbi, 0, &blknr, &offset);
> + KUNIT_EXPECT_EQ(test, (sector_t)0, blknr);
> + KUNIT_EXPECT_EQ(test, 0, offset);
> +
> + fat_get_blknr_offset(&sbi, (10 << 4) | 7, &blknr, &offset);
> + KUNIT_EXPECT_EQ(test, (sector_t)10, blknr);
> + KUNIT_EXPECT_EQ(test, 7, offset);
> +}
> +
> struct fat_timestamp_testcase {
> const char *name;
> struct timespec64 ts;
> @@ -181,6 +212,8 @@ static void fat_time_unix2fat_test(struct kunit *test)
>
> static struct kunit_case fat_test_cases[] = {
> KUNIT_CASE(fat_checksum_test),
> + KUNIT_CASE(fat_clus_to_blknr_test),
> + KUNIT_CASE(fat_get_blknr_offset_test),
> KUNIT_CASE_PARAM(fat_time_fat2unix_test, fat_time_gen_params),
> KUNIT_CASE_PARAM(fat_time_unix2fat_test, fat_time_gen_params),
> {},