littlefs/tests/test_exhaustion.toml

# test running a filesystem to exhaustion
[cases.test_exhaustion_normal]
defines.ERASE_CYCLES = 10
defines.ERASE_COUNT = 256 # small bd so test runs faster
defines.BLOCK_CYCLES = 'ERASE_CYCLES / 2'
defines.BADBLOCK_BEHAVIOR = [
    'LFS_EMUBD_BADBLOCK_PROGERROR',
    'LFS_EMUBD_BADBLOCK_ERASEERROR',
    'LFS_EMUBD_BADBLOCK_READERROR',
    'LFS_EMUBD_BADBLOCK_PROGNOOP',
    'LFS_EMUBD_BADBLOCK_ERASENOOP',
]
defines.FILES = 10
code = '''
    lfs_t lfs;
    lfs_format(&lfs, cfg) => 0;
    lfs_mount(&lfs, cfg) => 0;
    lfs_mkdir(&lfs, "roadrunner") => 0;
    lfs_unmount(&lfs) => 0;

    uint32_t cycle = 0;
    while (true) {
        lfs_mount(&lfs, cfg) => 0;
        for (uint32_t i = 0; i < FILES; i++) {
            // chose name, roughly random seed, and random 2^n size
            char path[1024];
            sprintf(path, "roadrunner/test%d", i);
            uint32_t prng = cycle * i;
            lfs_size_t size = 1 << ((TEST_PRNG(&prng) % 10)+2);

            lfs_file_t file;
            lfs_file_open(&lfs, &file, path,
                    LFS_O_WRONLY | LFS_O_CREAT | LFS_O_TRUNC) => 0;

            for (lfs_size_t j = 0; j < size; j++) {
                char c = 'a' + (TEST_PRNG(&prng) % 26);
                lfs_ssize_t res = lfs_file_write(&lfs, &file, &c, 1);
                assert(res == 1 || res == LFS_ERR_NOSPC);
                if (res == LFS_ERR_NOSPC) {
                    int err = lfs_file_close(&lfs, &file);
                    assert(err == 0 || err == LFS_ERR_NOSPC);
                    lfs_unmount(&lfs) => 0;
                    goto exhausted;
                }
            }

            int err = lfs_file_close(&lfs, &file);
            assert(err == 0 || err == LFS_ERR_NOSPC);
            if (err == LFS_ERR_NOSPC) {
                lfs_unmount(&lfs) => 0;
                goto exhausted;
            }
        }

        for (uint32_t i = 0; i < FILES; i++) {
            // check for errors
            char path[1024];
            sprintf(path, "roadrunner/test%d", i);
            uint32_t prng = cycle * i;
            lfs_size_t size = 1 << ((TEST_PRNG(&prng) % 10)+2);

            lfs_file_t file;
            lfs_file_open(&lfs, &file, path, LFS_O_RDONLY) => 0;
            for (lfs_size_t j = 0; j < size; j++) {
                char c = 'a' + (TEST_PRNG(&prng) % 26);
                char r;
                lfs_file_read(&lfs, &file, &r, 1) => 1;
                assert(r == c);
            }

            lfs_file_close(&lfs, &file) => 0;
        }
        lfs_unmount(&lfs) => 0;

        cycle += 1;
    }

exhausted:
    // should still be readable
    lfs_mount(&lfs, cfg) => 0;
    for (uint32_t i = 0; i < FILES; i++) {
        // check for errors
        char path[1024];
        sprintf(path, "roadrunner/test%d", i);
        struct lfs_info info;
        lfs_stat(&lfs, path, &info) => 0;
    }
    lfs_unmount(&lfs) => 0;

    LFS_WARN("completed %d cycles", cycle);
'''

# test running a filesystem to exhaustion
# which also requires expanding superblocks
[cases.test_exhaustion_superblocks]
defines.ERASE_CYCLES = 10
defines.ERASE_COUNT = 256 # small bd so test runs faster
defines.BLOCK_CYCLES = 'ERASE_CYCLES / 2'
defines.BADBLOCK_BEHAVIOR = [
    'LFS_EMUBD_BADBLOCK_PROGERROR',
    'LFS_EMUBD_BADBLOCK_ERASEERROR',
    'LFS_EMUBD_BADBLOCK_READERROR',
    'LFS_EMUBD_BADBLOCK_PROGNOOP',
    'LFS_EMUBD_BADBLOCK_ERASENOOP',
]
defines.FILES = 10
code = '''
    lfs_t lfs;
    lfs_format(&lfs, cfg) => 0;

    uint32_t cycle = 0;
    while (true) {
        lfs_mount(&lfs, cfg) => 0;
        for (uint32_t i = 0; i < FILES; i++) {
            // chose name, roughly random seed, and random 2^n size
            char path[1024];
            sprintf(path, "test%d", i);
            uint32_t prng = cycle * i;
            lfs_size_t size = 1 << ((TEST_PRNG(&prng) % 10)+2);

            lfs_file_t file;
            lfs_file_open(&lfs, &file, path,
                    LFS_O_WRONLY | LFS_O_CREAT | LFS_O_TRUNC) => 0;

            for (lfs_size_t j = 0; j < size; j++) {
                char c = 'a' + (TEST_PRNG(&prng) % 26);
                lfs_ssize_t res = lfs_file_write(&lfs, &file, &c, 1);
                assert(res == 1 || res == LFS_ERR_NOSPC);
                if (res == LFS_ERR_NOSPC) {
                    int err = lfs_file_close(&lfs, &file);
                    assert(err == 0 || err == LFS_ERR_NOSPC);
                    lfs_unmount(&lfs) => 0;
                    goto exhausted;
                }
            }

            int err = lfs_file_close(&lfs, &file);
            assert(err == 0 || err == LFS_ERR_NOSPC);
            if (err == LFS_ERR_NOSPC) {
                lfs_unmount(&lfs) => 0;
                goto exhausted;
            }
        }

        for (uint32_t i = 0; i < FILES; i++) {
            // check for errors
            char path[1024];
            sprintf(path, "test%d", i);
            uint32_t prng = cycle * i;
            lfs_size_t size = 1 << ((TEST_PRNG(&prng) % 10)+2);

            lfs_file_t file;
            lfs_file_open(&lfs, &file, path, LFS_O_RDONLY) => 0;
            for (lfs_size_t j = 0; j < size; j++) {
                char c = 'a' + (TEST_PRNG(&prng) % 26);
                char r;
                lfs_file_read(&lfs, &file, &r, 1) => 1;
                assert(r == c);
            }

            lfs_file_close(&lfs, &file) => 0;
        }
        lfs_unmount(&lfs) => 0;

        cycle += 1;
    }

exhausted:
    // should still be readable
    lfs_mount(&lfs, cfg) => 0;
    for (uint32_t i = 0; i < FILES; i++) {
        // check for errors
        char path[1024];
        struct lfs_info info;
        sprintf(path, "test%d", i);
        lfs_stat(&lfs, path, &info) => 0;
    }
    lfs_unmount(&lfs) => 0;

    LFS_WARN("completed %d cycles", cycle);
'''

# These are a sort of high-level litmus test for wear-leveling. One definition
# of wear-leveling is that increasing a block device's space translates directly
# into increasing the block devices lifetime. This is something we can actually
# check for.

# wear-level test running a filesystem to exhaustion
[cases.test_exhuastion_wear_leveling]
defines.ERASE_CYCLES = 20
defines.ERASE_COUNT = 256 # small bd so test runs faster
defines.BLOCK_CYCLES = 'ERASE_CYCLES / 2'
defines.FILES = 10
code = '''
    uint32_t run_cycles[2];
    const uint32_t run_block_count[2] = {BLOCK_COUNT/2, BLOCK_COUNT};

    for (int run = 0; run < 2; run++) {
        for (lfs_block_t b = 0; b < BLOCK_COUNT; b++) {
            lfs_emubd_setwear(cfg, b,
                    (b < run_block_count[run]) ? 0 : ERASE_CYCLES) => 0;
        }

        lfs_t lfs;
        lfs_format(&lfs, cfg) => 0;
        lfs_mount(&lfs, cfg) => 0;
        lfs_mkdir(&lfs, "roadrunner") => 0;
        lfs_unmount(&lfs) => 0;

        uint32_t cycle = 0;
        while (true) {
            lfs_mount(&lfs, cfg) => 0;
            for (uint32_t i = 0; i < FILES; i++) {
                // chose name, roughly random seed, and random 2^n size
                char path[1024];
                sprintf(path, "roadrunner/test%d", i);
                uint32_t prng = cycle * i;
                lfs_size_t size = 1 << ((TEST_PRNG(&prng) % 10)+2);

                lfs_file_t file;
                lfs_file_open(&lfs, &file, path,
                        LFS_O_WRONLY | LFS_O_CREAT | LFS_O_TRUNC) => 0;

                for (lfs_size_t j = 0; j < size; j++) {
                    char c = 'a' + (TEST_PRNG(&prng) % 26);
                    lfs_ssize_t res = lfs_file_write(&lfs, &file, &c, 1);
                    assert(res == 1 || res == LFS_ERR_NOSPC);
                    if (res == LFS_ERR_NOSPC) {
                        int err = lfs_file_close(&lfs, &file);
                        assert(err == 0 || err == LFS_ERR_NOSPC);
                        lfs_unmount(&lfs) => 0;
                        goto exhausted;
                    }
                }

                int err = lfs_file_close(&lfs, &file);
                assert(err == 0 || err == LFS_ERR_NOSPC);
                if (err == LFS_ERR_NOSPC) {
                    lfs_unmount(&lfs) => 0;
                    goto exhausted;
                }
            }

            for (uint32_t i = 0; i < FILES; i++) {
                // check for errors
                char path[1024];
                sprintf(path, "roadrunner/test%d", i);
                uint32_t prng = cycle * i;
                lfs_size_t size = 1 << ((TEST_PRNG(&prng) % 10)+2);

                lfs_file_t file;
                lfs_file_open(&lfs, &file, path, LFS_O_RDONLY) => 0;
                for (lfs_size_t j = 0; j < size; j++) {
                    char c = 'a' + (TEST_PRNG(&prng) % 26);
                    char r;
                    lfs_file_read(&lfs, &file, &r, 1) => 1;
                    assert(r == c);
                }

                lfs_file_close(&lfs, &file) => 0;
            }
            lfs_unmount(&lfs) => 0;

            cycle += 1;
        }

exhausted:
        // should still be readable
        lfs_mount(&lfs, cfg) => 0;
        for (uint32_t i = 0; i < FILES; i++) {
            // check for errors
            char path[1024];
            struct lfs_info info;
            sprintf(path, "roadrunner/test%d", i);
            lfs_stat(&lfs, path, &info) => 0;
        }
        lfs_unmount(&lfs) => 0;

        run_cycles[run] = cycle;
        LFS_WARN("completed %d blocks %d cycles",
                run_block_count[run], run_cycles[run]);
    }

    // check we increased the lifetime by 2x with ~10% error
    LFS_ASSERT(run_cycles[1]*110/100 > 2*run_cycles[0]);
'''

# wear-level test + expanding superblock
[cases.test_exhaustion_wear_leveling_superblocks]
defines.ERASE_CYCLES = 20
defines.ERASE_COUNT = 256 # small bd so test runs faster
defines.BLOCK_CYCLES = 'ERASE_CYCLES / 2'
defines.FILES = 10
code = '''
    uint32_t run_cycles[2];
    const uint32_t run_block_count[2] = {BLOCK_COUNT/2, BLOCK_COUNT};

    for (int run = 0; run < 2; run++) {
        for (lfs_block_t b = 0; b < BLOCK_COUNT; b++) {
            lfs_emubd_setwear(cfg, b,
                    (b < run_block_count[run]) ? 0 : ERASE_CYCLES) => 0;
        }

        lfs_t lfs;
        lfs_format(&lfs, cfg) => 0;

        uint32_t cycle = 0;
        while (true) {
            lfs_mount(&lfs, cfg) => 0;
            for (uint32_t i = 0; i < FILES; i++) {
                // chose name, roughly random seed, and random 2^n size
                char path[1024];
                sprintf(path, "test%d", i);
                uint32_t prng = cycle * i;
                lfs_size_t size = 1 << ((TEST_PRNG(&prng) % 10)+2);

                lfs_file_t file;
                lfs_file_open(&lfs, &file, path,
                        LFS_O_WRONLY | LFS_O_CREAT | LFS_O_TRUNC) => 0;

                for (lfs_size_t j = 0; j < size; j++) {
                    char c = 'a' + (TEST_PRNG(&prng) % 26);
                    lfs_ssize_t res = lfs_file_write(&lfs, &file, &c, 1);
                    assert(res == 1 || res == LFS_ERR_NOSPC);
                    if (res == LFS_ERR_NOSPC) {
                        int err = lfs_file_close(&lfs, &file);
                        assert(err == 0 || err == LFS_ERR_NOSPC);
                        lfs_unmount(&lfs) => 0;
                        goto exhausted;
                    }
                }

                int err = lfs_file_close(&lfs, &file);
                assert(err == 0 || err == LFS_ERR_NOSPC);
                if (err == LFS_ERR_NOSPC) {
                    lfs_unmount(&lfs) => 0;
                    goto exhausted;
                }
            }

            for (uint32_t i = 0; i < FILES; i++) {
                // check for errors
                char path[1024];
                sprintf(path, "test%d", i);
                uint32_t prng = cycle * i;
                lfs_size_t size = 1 << ((TEST_PRNG(&prng) % 10)+2);

                lfs_file_t file;
                lfs_file_open(&lfs, &file, path, LFS_O_RDONLY) => 0;
                for (lfs_size_t j = 0; j < size; j++) {
                    char c = 'a' + (TEST_PRNG(&prng) % 26);
                    char r;
                    lfs_file_read(&lfs, &file, &r, 1) => 1;
                    assert(r == c);
                }

                lfs_file_close(&lfs, &file) => 0;
            }
            lfs_unmount(&lfs) => 0;

            cycle += 1;
        }

exhausted:
        // should still be readable
        lfs_mount(&lfs, cfg) => 0;
        for (uint32_t i = 0; i < FILES; i++) {
            // check for errors
            char path[1024];
            struct lfs_info info;
            sprintf(path, "test%d", i);
            lfs_stat(&lfs, path, &info) => 0;
        }
        lfs_unmount(&lfs) => 0;

        run_cycles[run] = cycle;
        LFS_WARN("completed %d blocks %d cycles",
                run_block_count[run], run_cycles[run]);
    }

    // check we increased the lifetime by 2x with ~10% error
    LFS_ASSERT(run_cycles[1]*110/100 > 2*run_cycles[0]);
'''

# test that we wear blocks roughly evenly
[cases.test_exhaustion_wear_distribution]
defines.ERASE_CYCLES = 0xffffffff
defines.ERASE_COUNT = 256 # small bd so test runs faster
defines.BLOCK_CYCLES = [5, 4, 3, 2, 1]
defines.CYCLES = 100
defines.FILES = 10
if = 'BLOCK_CYCLES < CYCLES/10'
code = '''
    lfs_t lfs;
    lfs_format(&lfs, cfg) => 0;
    lfs_mount(&lfs, cfg) => 0;
    lfs_mkdir(&lfs, "roadrunner") => 0;
    lfs_unmount(&lfs) => 0;

    uint32_t cycle = 0;
    while (cycle < CYCLES) {
        lfs_mount(&lfs, cfg) => 0;
        for (uint32_t i = 0; i < FILES; i++) {
            // chose name, roughly random seed, and random 2^n size
            char path[1024];
            sprintf(path, "roadrunner/test%d", i);
            uint32_t prng = cycle * i;
            lfs_size_t size = 1 << 4; //((TEST_PRNG(&prng) % 10)+2);

            lfs_file_t file;
            lfs_file_open(&lfs, &file, path,
                    LFS_O_WRONLY | LFS_O_CREAT | LFS_O_TRUNC) => 0;

            for (lfs_size_t j = 0; j < size; j++) {
                char c = 'a' + (TEST_PRNG(&prng) % 26);
                lfs_ssize_t res = lfs_file_write(&lfs, &file, &c, 1);
                assert(res == 1 || res == LFS_ERR_NOSPC);
                if (res == LFS_ERR_NOSPC) {
                    int err = lfs_file_close(&lfs, &file);
                    assert(err == 0 || err == LFS_ERR_NOSPC);
                    lfs_unmount(&lfs) => 0;
                    goto exhausted;
                }
            }

            int err = lfs_file_close(&lfs, &file);
            assert(err == 0 || err == LFS_ERR_NOSPC);
            if (err == LFS_ERR_NOSPC) {
                lfs_unmount(&lfs) => 0;
                goto exhausted;
            }
        }

        for (uint32_t i = 0; i < FILES; i++) {
            // check for errors
            char path[1024];
            sprintf(path, "roadrunner/test%d", i);
            uint32_t prng = cycle * i;
            lfs_size_t size = 1 << 4; //((TEST_PRNG(&prng) % 10)+2);

            lfs_file_t file;
            lfs_file_open(&lfs, &file, path, LFS_O_RDONLY) => 0;
            for (lfs_size_t j = 0; j < size; j++) {
                char c = 'a' + (TEST_PRNG(&prng) % 26);
                char r;
                lfs_file_read(&lfs, &file, &r, 1) => 1;
                assert(r == c);
            }

            lfs_file_close(&lfs, &file) => 0;
        }
        lfs_unmount(&lfs) => 0;

        cycle += 1;
    }

exhausted:
    // should still be readable
    lfs_mount(&lfs, cfg) => 0;
    for (uint32_t i = 0; i < FILES; i++) {
        // check for errors
        char path[1024];
        struct lfs_info info;
        sprintf(path, "roadrunner/test%d", i);
        lfs_stat(&lfs, path, &info) => 0;
    }
    lfs_unmount(&lfs) => 0;

    LFS_WARN("completed %d cycles", cycle);

    // check the wear on our block device
    lfs_emubd_wear_t minwear = -1;
    lfs_emubd_wear_t totalwear = 0;
    lfs_emubd_wear_t maxwear = 0;
    // skip 0 and 1 as superblock movement is intentionally avoided
    for (lfs_block_t b = 2; b < BLOCK_COUNT; b++) {
        lfs_emubd_wear_t wear = lfs_emubd_wear(cfg, b);
        printf("%08x: wear %d\n", b, wear);
        assert(wear >= 0);
        if (wear < minwear) {
            minwear = wear;
        }
        if (wear > maxwear) {
            maxwear = wear;
        }
        totalwear += wear;
    }
    lfs_emubd_wear_t avgwear = totalwear / BLOCK_COUNT;
    LFS_WARN("max wear: %d cycles", maxwear);
    LFS_WARN("avg wear: %d cycles", totalwear / (int)BLOCK_COUNT);
    LFS_WARN("min wear: %d cycles", minwear);

    // find standard deviation^2
    lfs_emubd_wear_t dev2 = 0;
    for (lfs_block_t b = 2; b < BLOCK_COUNT; b++) {
        lfs_emubd_wear_t wear = lfs_emubd_wear(cfg, b);
        assert(wear >= 0);
        lfs_emubd_swear_t diff = wear - avgwear;
        dev2 += diff*diff;
    }
    dev2 /= totalwear;
    LFS_WARN("std dev^2: %d", dev2);
    assert(dev2 < 8);
'''