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From:   Iurii Zaikin <yzaikin@google.com>
Date:   Wed, 9 Oct 2019 19:40:32 -0700
Message-ID: <CAAXuY3qavRvDxQvyitxJh8aWeOgcPd_Ab3G3g61yxnYRiiU6NA@mail.gmail.com>
Subject: Re: [PATCH v1] fs/ext4/inode-test: KUnit test for ext4 inode.
To:     Shuah Khan <skhan@linuxfoundation.org>
Cc:     "open list:KERNEL SELFTEST FRAMEWORK" 
        <linux-kselftest@vger.kernel.org>, linux-ext4@vger.kernel.org,
        "Theodore Ts'o" <tytso@mit.edu>, adilger.kernel@dilger.ca,
        kunit-dev@googlegroups.com,
        Brendan Higgins <brendanhiggins@google.com>
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>
> Hi Iurii,
>
> Thanks for the patch.
>
> On 10/8/19 8:42 PM, Iurii Zaikin wrote:
> > Note: this patch is intended to be applied against kselftest/test branch:
> > https://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest.git/log/?h=test
> >
>
>
> This doesn't belong here. You can add it to commit header
>
> [PATCH linux-kselftest/test] also you don't need v1 in there.
>
> > KUnit tests for decoding extended 64 bit timestamps.
>
> Please give more details on what these tests do. More information
> on range of timestamps would be helpful. I see you have 2038 test
> and it would be great to call out the ranges and conditions it is
> resting.
Added the link to the ext4 docs from which the tests were derived.
>
> >
> > Signed-off-by: Iurii Zaikin <yzaikin@google.com>
> > ---
> >   fs/ext4/Kconfig      |  12 +++
> >   fs/ext4/Makefile     |   1 +
> >   fs/ext4/inode-test.c | 217 +++++++++++++++++++++++++++++++++++++++++++
> >   3 files changed, 230 insertions(+)
> >   create mode 100644 fs/ext4/inode-test.c
> >
> > diff --git a/fs/ext4/Kconfig b/fs/ext4/Kconfig
> > index cbb5ca830e57..72c26abbce4c 100644
> > --- a/fs/ext4/Kconfig
> > +++ b/fs/ext4/Kconfig
> > @@ -106,3 +106,15 @@ config EXT4_DEBUG
> >     If you select Y here, then you will be able to turn on debugging
> >     with a command such as:
> >    echo 1 > /sys/module/ext4/parameters/mballoc_debug
> > +
> > +config EXT4_INODE_KUNIT_TEST
> > + bool "KUnit test for ext4 inode"
> > + depends on EXT4_FS
> > + depends on KUNIT
> > + help
> > +  This builds the ext4 inode sysctl unit test, which runs on boot.
> > +  Tests the encoding correctness of ext4 inode.
> > +  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/ext4/Makefile b/fs/ext4/Makefile
> > index b17ddc229ac5..1eeb8b449255 100644
> > --- a/fs/ext4/Makefile
> > +++ b/fs/ext4/Makefile
> > @@ -13,4 +13,5 @@ ext4-y := balloc.o bitmap.o block_validity.o dir.o
> > ext4_jbd2.o extents.o \
> >
> >   ext4-$(CONFIG_EXT4_FS_POSIX_ACL) += acl.o
> >   ext4-$(CONFIG_EXT4_FS_SECURITY) += xattr_security.o
> > +ext4-$(CONFIG_EXT4_INODE_KUNIT_TEST) += inode-test.o
> >   ext4-$(CONFIG_FS_VERITY) += verity.o
> > diff --git a/fs/ext4/inode-test.c b/fs/ext4/inode-test.c
> > new file mode 100644
> > index 000000000000..0ecb8dd5e0c5
> > --- /dev/null
> > +++ b/fs/ext4/inode-test.c
> > @@ -0,0 +1,217 @@
> > +// SPDX-License-Identifier: GPL-2.0
>
> Follow the commenting style recommended in the coding-style doc.
> /* ---- */
Done
>
> > +/*
> > + * KUnit test of ext4 inode.
> > + */
> > +
> > +#include <kunit/test.h>
> > +#include <linux/kernel.h>
> > +#include <linux/time64.h>
> > +
> > +#include "ext4.h"
> > +
> > +// binary: 00000000 00000000 00000000 00000000
> > +#define LOWER_MSB_0 0L
> > +// binary: 01111111 11111111 11111111 11111111
> > +#define UPPER_MSB_0 0x7fffffffL
> > +// binary: 10000000 00000000 00000000 00000000
> > +#define LOWER_MSB_1 (-0x80000000L)
> > +// binary: 11111111 11111111 11111111 11111111
> > +#define UPPER_MSB_1 (-1L)
> > +
> > +#define CASE_NAME_FORMAT "%s: msb:%x lower_bound:%x extra_bits: %x"
> > +
> > +struct timestamp_expectation {
> > + const char *test_case_name;
> > + struct timespec64 expected;
> > + u32 extra_bits;
> > + bool msb_set;
> > + bool lower_bound;
> > +};
> > +
> > +static time64_t get_32bit_time(const struct timestamp_expectation * const test)
> > +{
> > + if (test->msb_set) {
> > + if (test->lower_bound)
> > + return LOWER_MSB_1;
> > +
> > + return UPPER_MSB_1;
> > + }
>
> Can you add information on what you are trying to test.
> Please do the same for all tests.
>
> > +
> > + if (test->lower_bound)
> > + return LOWER_MSB_0;
> > + return UPPER_MSB_0;
> > +}
> > +
> > +
> > +static void inode_test_xtimestamp_decoding(struct kunit *test)
> > +{
> > + const struct timestamp_expectation test_data[] = {
> > + {
> > + .test_case_name = "1901-12-13",
> > + .msb_set = true,
> > + .lower_bound = true,
> > + .extra_bits = 0,
> > + .expected = {.tv_sec = -0x80000000LL, .tv_nsec = 0L},
> > + },
> > +
>
> I see that you use the same tv_nsec for all tests. Is there
> a reason for that? Would it be helpful to vary it?
Done.
>
> > + {
> > + .test_case_name = "1969-12-31",
> > + .msb_set = true,
> > + .lower_bound = false,
> > + .extra_bits = 0,
> > + .expected = {.tv_sec = -1LL, .tv_nsec = 0L},
> > + },
> > +
> > + {
> > + .test_case_name = "1970-01-01",
> > + .msb_set = false,
> > + .lower_bound = true,
> > + .extra_bits = 0,
> > + .expected = {0LL, 0L},
> > + },
> > +
> > + {
> > + .test_case_name = "2038-01-19",
> > + .msb_set = false,
> > + .lower_bound = false,
> > + .extra_bits = 0,
> > + .expected = {.tv_sec = 0x7fffffffLL, .tv_nsec = 0L},
> > + },
> > +
> > + {
> > + .test_case_name = "2038-01-19",
> > + .msb_set = true,
> > + .lower_bound = true,
> > + .extra_bits = 1,
> > + .expected = {.tv_sec = 0x80000000LL, .tv_nsec = 0L},
> > + },
> > +
> > + {
> > + .test_case_name = "2106-02-07",
> > + .msb_set = true,
> > + .lower_bound = false,
> > + .extra_bits = 1,
> > + .expected = {.tv_sec = 0xffffffffLL, .tv_nsec = 0L},
> > + },
> > +
> > + {
> > + .test_case_name = "2106-02-07",
> > + .msb_set = false,
> > + .lower_bound = true,
> > + .extra_bits = 1,
> > + .expected = {.tv_sec = 0x100000000LL, .tv_nsec = 0LL},
> > + },
> > +
> > + {
> > + .test_case_name = "2174-02-25",
> > + .msb_set = false,
> > + .lower_bound = false,
> > + .extra_bits = 1,
> > + .expected = {.tv_sec = 0x17fffffffLL, .tv_nsec = 0L},
> > + },
> > +
> > + {
> > + .test_case_name = "2174-02-25",
> > + .msb_set = true,
> > + .lower_bound = true,
> > + .extra_bits =  2,
> > + .expected = {.tv_sec = 0x180000000LL, .tv_nsec = 0L},
> > + },
> > +
> > + {
> > + .test_case_name = "2242-03-16",
> > + .msb_set = true,
> > + .lower_bound = false,
> > + .extra_bits = 2,
> > + .expected = {.tv_sec = 0x1ffffffffLL, .tv_nsec = 0L},
> > + },
> > +
> > + {
> > + .test_case_name = "2242-03-16",
> > + .msb_set = false,
> > + .lower_bound = true,
> > + .extra_bits = 2,
> > + .expected = {.tv_sec = 0x200000000LL, .tv_nsec = 0L},
> > + },
> > +
> > + {
> > + .test_case_name = " 2310-04-04",
> > + .msb_set = false,
> > + .lower_bound = false,
> > + .extra_bits = 2,
> > + .expected = {.tv_sec = 0x27fffffffLL, .tv_nsec = 0L},
> > + },
> > +
>
> Get rid of this. Add it when you can add it later. I don't
> like to see these TODOs with blocks of code commented out.
Done
>
> > + /* TODO: enable when legacy encoding in ext4.h is disabled.
> > + *{
> > + * .test_case_name = "2310-04-04",
> > + * .msb_set = true,
> > + * .lower_bound = true,
> > + * .extra_bits = 3,
> > + * .expected = {.tv_sec = 0x280000000LL, .tv_nsec = 0L},
> > + *},
> > + *
> > + *{
> > + * .test_case_name = "2378-04-22",
> > + * .msb_set = true,
> > + * .lower_bound = false,
> > + * .extra_bits = 3,
> > + * .expected = {.tv_sec = 0x2ffffffffLL, .tv_nsec = 0L},
> > + * },
> > + */
> > +
> > + {
> > + .test_case_name = "2378-04-22",
> > + .msb_set = false,
> > + .lower_bound = true,
> > + .extra_bits = 3,
> > + .expected = {.tv_sec = 0x300000000LL, .tv_nsec = 0L},
> > + },
> > +
> > + {
> > + .test_case_name = "2446-05-10",
> > + .msb_set = false,
> > + .lower_bound = false,
> > + .extra_bits = 3,
> > + .expected = {.tv_sec = 0x37fffffffLL, .tv_nsec = 0L},
> > + }
> > + };
> > +
> > + struct timespec64 timestamp;
> > + int i;
> > +
> > + for (i = 0; i < ARRAY_SIZE(test_data); ++i) {
> > + timestamp.tv_sec = get_32bit_time(&test_data[i]);
> > + ext4_decode_extra_time(&timestamp,
> > +       cpu_to_le32(test_data[i].extra_bits));
> > +
> > + KUNIT_EXPECT_EQ_MSG(test,
> > +    test_data[i].expected.tv_sec,
> > +    timestamp.tv_sec,
> > +    CASE_NAME_FORMAT,
> > +    test_data[i].test_case_name,
> > +    test_data[i].msb_set,
> > +    test_data[i].lower_bound,
> > +    test_data[i].extra_bits);
> > + KUNIT_EXPECT_EQ_MSG(test,
> > +    test_data[i].expected.tv_nsec,
> > +    timestamp.tv_nsec,
> > +    CASE_NAME_FORMAT,
> > +    test_data[i].test_case_name,
> > +    test_data[i].msb_set,
> > +    test_data[i].lower_bound,
> > +    test_data[i].extra_bits);
> > + }
> > +}
> > +
> > +static struct kunit_case ext4_inode_test_cases[] = {
> > + KUNIT_CASE(inode_test_xtimestamp_decoding),
> > + {}
> > +};
> > +
> > +static struct kunit_suite ext4_inode_test_suite = {
> > + .name = "ext4_inode_test",
> > + .test_cases = ext4_inode_test_cases,
> > +};
> > +
> > +kunit_test_suite(ext4_inode_test_suite);
> > --
> > 2.23.0.700.g56cf767bdb-goog
> >
>
> thanks,
> -- Shuah

> Whitespace in this patch (ok, I'm assuming that there was some whitespace)
> is severely damaged.  I.e., gone.
Sorry, used different email client this time.
> I'd suggest using "ext4: add kunit test for decoding extended
> timestamps" as the one-line summary, and we probably don't need
> anything else.
Done
> Should we perhaps just call the cofnig "EXT4_KUNIT_TESTS"?
Done