// SPDX-License-Identifier: GPL-2.0
/*
 * Written by Ojaswin Mujoo <ojaswin@linux.ibm.com> (IBM)
 *
 * These Kunit tests are designed to test the functionality of
 * extent split and conversion in ext4.
 *
 * Currently, ext4 can split extents in 2 ways:
 * 1. By splitting the extents in the extent tree and optionally converting them
 *    to written or unwritten based on flags passed.
 * 2. In case 1 encounters an error, ext4 instead zerooes out the unwritten
 *    areas of the extent and marks the complete extent written.
 *
 * The primary function that handles this is ext4_split_convert_extents().
 *
 * We test both of the methods of split. The behavior we try to enforce is:
 * 1. When passing EXT4_GET_BLOCKS_CONVERT flag to ext4_split_convert_extents(),
 *    the split extent should be converted to initialized.
 * 2. When passing EXT4_GET_BLOCKS_CONVERT_UNWRITTEN flag to
 *    ext4_split_convert_extents(), the split extent should be converted to
 *    uninitialized.
 * 3. In case we use the zeroout method, then we should correctly write zeroes
 *    to the unwritten areas of the extent and we should not corrupt/leak any
 *    data.
 *
 * Enforcing 1 and 2 is straight forward, we just setup a minimal inode with
 * extent tree, call ext4_split_convert_extents() and check the final state of
 * the extent tree.
 *
 * For zeroout testing, we maintain a separate buffer which represents the disk
 * data corresponding to the extents. We then override ext4's zeroout functions
 * to instead write zeroes to our buffer. Then, we override
 * ext4_ext_insert_extent() to return -ENOSPC, which triggers the zeroout.
 * Finally, we check the state of the extent tree and zeroout buffer to confirm
 * everything went well.
 */

#include <kunit/test.h>
#include <kunit/static_stub.h>
#include <linux/gfp_types.h>
#include <linux/stddef.h>

#include "ext4.h"
#include "ext4_extents.h"

#define EXT_DATA_PBLK 100
#define EXT_DATA_LBLK 10
#define EXT_DATA_LEN 3

struct kunit_ctx {
        /*
         * Ext4 inode which has only 1 unwrit extent
         */
        struct ext4_inode_info *k_ei;
        /*
         * Represents the underlying data area (used for zeroout testing)
         */
        char *k_data;
} k_ctx;

/*
 * describes the state of an expected extent in extent tree.
 */
struct kunit_ext_state {
        ext4_lblk_t ex_lblk;
        ext4_lblk_t ex_len;
        bool is_unwrit;
};

/*
 * describes the state of the data area of a writ extent. Used for testing
 * correctness of zeroout.
 */
struct kunit_ext_data_state {
        char exp_char;
        ext4_lblk_t off_blk;
        ext4_lblk_t len_blk;
};

enum kunit_test_types {
        TEST_SPLIT_CONVERT,
        TEST_CREATE_BLOCKS,
};

struct kunit_ext_test_param {
        /* description of test */
        char *desc;

        /* determines which function will be tested */
        int type;

        /* is extent unwrit at beginning of test */
        bool is_unwrit_at_start;

        /* flags to pass while splitting */
        int split_flags;

        /* map describing range to split */
        struct ext4_map_blocks split_map;

        /* disable zeroout */
        bool disable_zeroout;

        /* no of extents expected after split */
        int nr_exp_ext;

        /*
         * expected state of extents after split. We will never split into more
         * than 3 extents
         */
        struct kunit_ext_state exp_ext_state[3];

        /* Below fields used for zeroout tests */

        bool is_zeroout_test;
        /*
         * no of expected data segments (zeroout tests). Example, if we expect
         * data to be 4kb 0s, followed by 8kb non-zero, then nr_exp_data_segs==2
         */
        int nr_exp_data_segs;

        /*
         * expected state of data area after zeroout.
         */
        struct kunit_ext_data_state exp_data_state[3];
};

static void ext_kill_sb(struct super_block *sb)
{
        generic_shutdown_super(sb);
}

static int ext_set(struct super_block *sb, void *data)
{
        return 0;
}

static struct file_system_type ext_fs_type = {
        .name = "extents test",
        .kill_sb = ext_kill_sb,
};

static void extents_kunit_exit(struct kunit *test)
{
        struct super_block *sb = k_ctx.k_ei->vfs_inode.i_sb;
        struct ext4_sb_info *sbi = sb->s_fs_info;

        ext4_es_unregister_shrinker(sbi);
        kfree(sbi);
        kfree(k_ctx.k_ei);
        kfree(k_ctx.k_data);
}

static int __ext4_ext_dirty_stub(const char *where, unsigned int line,
                                 handle_t *handle, struct inode *inode,
                                 struct ext4_ext_path *path)
{
        return 0;
}

static struct ext4_ext_path *
ext4_ext_insert_extent_stub(handle_t *handle, struct inode *inode,
                            struct ext4_ext_path *path,
                            struct ext4_extent *newext, int gb_flags)
{
        return ERR_PTR(-ENOSPC);
}

/*
 * We will zeroout the equivalent range in the data area
 */
static int ext4_ext_zeroout_stub(struct inode *inode, struct ext4_extent *ex)
{
        ext4_lblk_t ee_block, off_blk;
        loff_t ee_len;
        loff_t off_bytes;
        struct kunit *test = kunit_get_current_test();

        ee_block = le32_to_cpu(ex->ee_block);
        ee_len = ext4_ext_get_actual_len(ex);

        KUNIT_EXPECT_EQ_MSG(test, 1, ee_block >= EXT_DATA_LBLK, "ee_block=%d",
                            ee_block);
        KUNIT_EXPECT_EQ(test, 1,
                        ee_block + ee_len <= EXT_DATA_LBLK + EXT_DATA_LEN);

        off_blk = ee_block - EXT_DATA_LBLK;
        off_bytes = off_blk << inode->i_sb->s_blocksize_bits;
        memset(k_ctx.k_data + off_bytes, 0,
               ee_len << inode->i_sb->s_blocksize_bits);

        return 0;
}

static int ext4_issue_zeroout_stub(struct inode *inode, ext4_lblk_t lblk,
                                   ext4_fsblk_t pblk, ext4_lblk_t len)
{
        ext4_lblk_t off_blk;
        loff_t off_bytes;
        struct kunit *test = kunit_get_current_test();

        kunit_log(KERN_ALERT, test,
                  "%s: lblk=%u pblk=%llu len=%u", __func__, lblk, pblk, len);
        KUNIT_EXPECT_EQ(test, 1, lblk >= EXT_DATA_LBLK);
        KUNIT_EXPECT_EQ(test, 1, lblk + len <= EXT_DATA_LBLK + EXT_DATA_LEN);
        KUNIT_EXPECT_EQ(test, 1, lblk - EXT_DATA_LBLK == pblk - EXT_DATA_PBLK);

        off_blk = lblk - EXT_DATA_LBLK;
        off_bytes = off_blk << inode->i_sb->s_blocksize_bits;
        memset(k_ctx.k_data + off_bytes, 0,
               len << inode->i_sb->s_blocksize_bits);

        return 0;
}

static int extents_kunit_init(struct kunit *test)
{
        struct ext4_extent_header *eh = NULL;
        struct ext4_inode_info *ei;
        struct inode *inode;
        struct super_block *sb;
        struct ext4_sb_info *sbi = NULL;
        struct kunit_ext_test_param *param =
                (struct kunit_ext_test_param *)(test->param_value);
        int err;

        sb = sget(&ext_fs_type, NULL, ext_set, 0, NULL);
        if (IS_ERR(sb))
                return PTR_ERR(sb);

        sb->s_blocksize = 4096;
        sb->s_blocksize_bits = 12;

        sbi = kzalloc_obj(struct ext4_sb_info);
        if (sbi == NULL)
                return -ENOMEM;

        sbi->s_sb = sb;
        sb->s_fs_info = sbi;

        if (!param || !param->disable_zeroout)
                sbi->s_extent_max_zeroout_kb = 32;

        /* setup the mock inode */
        k_ctx.k_ei = kzalloc_obj(struct ext4_inode_info);
        if (k_ctx.k_ei == NULL)
                return -ENOMEM;
        ei = k_ctx.k_ei;
        inode = &ei->vfs_inode;

        err = ext4_es_register_shrinker(sbi);
        if (err)
                return err;

        ext4_es_init_tree(&ei->i_es_tree);
        rwlock_init(&ei->i_es_lock);
        INIT_LIST_HEAD(&ei->i_es_list);
        ei->i_es_all_nr = 0;
        ei->i_es_shk_nr = 0;
        ei->i_es_shrink_lblk = 0;

        ei->i_disksize = (EXT_DATA_LBLK + EXT_DATA_LEN + 10)
                         << sb->s_blocksize_bits;
        ei->i_flags = 0;
        ext4_set_inode_flag(inode, EXT4_INODE_EXTENTS);
        inode->i_sb = sb;

        k_ctx.k_data = kzalloc(EXT_DATA_LEN * 4096, GFP_KERNEL);
        if (k_ctx.k_data == NULL)
                return -ENOMEM;

        /*
         * set the data area to a junk value
         */
        memset(k_ctx.k_data, 'X', EXT_DATA_LEN * 4096);

        /* create a tree with depth 0 */
        eh = (struct ext4_extent_header *)k_ctx.k_ei->i_data;

        /* Fill extent header */
        eh = ext_inode_hdr(&k_ctx.k_ei->vfs_inode);
        eh->eh_depth = 0;
        eh->eh_entries = cpu_to_le16(1);
        eh->eh_magic = EXT4_EXT_MAGIC;
        eh->eh_max = cpu_to_le16(ext4_ext_space_root_idx_test(
                                        &k_ctx.k_ei->vfs_inode, 0));
        eh->eh_generation = 0;

        /*
         * add 1 extent in leaf node covering:
         * - lblks: [EXT_DATA_LBLK, EXT_DATA_LBLK * + EXT_DATA_LEN)
         * - pblks: [EXT_DATA_PBLK, EXT_DATA_PBLK + EXT_DATA_LEN)
         */
        EXT_FIRST_EXTENT(eh)->ee_block = cpu_to_le32(EXT_DATA_LBLK);
        EXT_FIRST_EXTENT(eh)->ee_len = cpu_to_le16(EXT_DATA_LEN);
        ext4_ext_store_pblock(EXT_FIRST_EXTENT(eh), EXT_DATA_PBLK);
        if (!param || param->is_unwrit_at_start)
                ext4_ext_mark_unwritten(EXT_FIRST_EXTENT(eh));

        ext4_es_insert_extent(inode, EXT_DATA_LBLK, EXT_DATA_LEN, EXT_DATA_PBLK,
                              ext4_ext_is_unwritten(EXT_FIRST_EXTENT(eh)) ?
                                      EXTENT_STATUS_UNWRITTEN :
                                      EXTENT_STATUS_WRITTEN,
                              0);

        /* Add stubs */
        kunit_activate_static_stub(test, __ext4_ext_dirty,
                                   __ext4_ext_dirty_stub);
        kunit_activate_static_stub(test, ext4_ext_zeroout, ext4_ext_zeroout_stub);
        kunit_activate_static_stub(test, ext4_issue_zeroout,
                                   ext4_issue_zeroout_stub);
        return 0;
}

/*
 * Return 1 if all bytes in the buf equal to c, else return the offset of first mismatch
 */
static int check_buffer(char *buf, int c, int size)
{
        void *ret = NULL;

        ret = memchr_inv(buf, c, size);
        if (ret  == NULL)
                return 0;

        kunit_log(KERN_ALERT, kunit_get_current_test(),
                  "# %s: wrong char found at offset %u (expected:%d got:%d)", __func__,
                  (u32)((char *)ret - buf), c, *((char *)ret));
        return 1;
}

/*
 * Simulate a map block call by first calling ext4_map_query_blocks() to
 * correctly populate map flags and pblk and then call the
 * ext4_map_create_blocks() to do actual split and conversion. This is easier
 * than calling ext4_map_blocks() because that needs mocking a lot of unrelated
 * functions.
 */
static void ext4_map_create_blocks_helper(struct kunit *test,
                                          struct inode *inode,
                                          struct ext4_map_blocks *map,
                                          int flags)
{
        int retval = 0;

        retval = ext4_map_query_blocks(NULL, inode, map, flags);
        if (retval < 0) {
                KUNIT_FAIL(test,
                           "ext4_map_query_blocks() failed. Cannot proceed\n");
                return;
        }

        ext4_map_create_blocks(NULL, inode, map, flags);
}

static void test_split_convert(struct kunit *test)
{
        struct ext4_ext_path *path;
        struct inode *inode = &k_ctx.k_ei->vfs_inode;
        struct ext4_extent *ex;
        struct ext4_map_blocks map;
        const struct kunit_ext_test_param *param =
                (const struct kunit_ext_test_param *)(test->param_value);
        int blkbits = inode->i_sb->s_blocksize_bits;

        if (param->is_zeroout_test)
                /*
                 * Force zeroout by making ext4_ext_insert_extent return ENOSPC
                 */
                kunit_activate_static_stub(test, ext4_ext_insert_extent,
                                           ext4_ext_insert_extent_stub);

        path = ext4_find_extent(inode, EXT_DATA_LBLK, NULL, EXT4_EX_NOCACHE);
        ex = path->p_ext;
        KUNIT_EXPECT_EQ(test, EXT_DATA_LBLK, le32_to_cpu(ex->ee_block));
        KUNIT_EXPECT_EQ(test, EXT_DATA_LEN, ext4_ext_get_actual_len(ex));
        KUNIT_EXPECT_EQ(test, param->is_unwrit_at_start,
                        ext4_ext_is_unwritten(ex));
        if (param->is_zeroout_test)
                KUNIT_EXPECT_EQ(test, 0,
                                check_buffer(k_ctx.k_data, 'X',
                                             EXT_DATA_LEN << blkbits));

        map.m_lblk = param->split_map.m_lblk;
        map.m_len = param->split_map.m_len;

        switch (param->type) {
        case TEST_SPLIT_CONVERT:
                path = ext4_split_convert_extents_test(NULL, inode, &map,
                                        path, param->split_flags, NULL);
                break;
        case TEST_CREATE_BLOCKS:
                ext4_map_create_blocks_helper(test, inode, &map, param->split_flags);
                break;
        default:
                KUNIT_FAIL(test, "param->type %d not support.", param->type);
        }

        path = ext4_find_extent(inode, EXT_DATA_LBLK, NULL, EXT4_EX_NOCACHE);
        ex = path->p_ext;

        for (int i = 0; i < param->nr_exp_ext; i++) {
                struct kunit_ext_state exp_ext = param->exp_ext_state[i];
                bool es_check_needed = param->type != TEST_SPLIT_CONVERT;
                struct extent_status es;
                int contains_ex, ex_end, es_end, es_pblk;

                KUNIT_EXPECT_EQ(test, exp_ext.ex_lblk,
                                le32_to_cpu(ex->ee_block));
                KUNIT_EXPECT_EQ(test, exp_ext.ex_len,
                                ext4_ext_get_actual_len(ex));
                KUNIT_EXPECT_EQ(test, exp_ext.is_unwrit,
                                ext4_ext_is_unwritten(ex));
                /*
                 * Confirm extent cache is in sync. Note that es cache can be
                 * merged even when on-disk extents are not so take that into
                 * account.
                 *
                 * Also, ext4_split_convert_extents() forces EXT4_EX_NOCACHE hence
                 * es status are ignored for that case.
                 */
                if (es_check_needed) {
                        ext4_es_lookup_extent(inode, le32_to_cpu(ex->ee_block),
                                              NULL, &es, NULL);

                        ex_end = exp_ext.ex_lblk + exp_ext.ex_len;
                        es_end = es.es_lblk + es.es_len;
                        contains_ex = es.es_lblk <= exp_ext.ex_lblk &&
                                      es_end >= ex_end;
                        es_pblk = ext4_es_pblock(&es) +
                                  (exp_ext.ex_lblk - es.es_lblk);

                        KUNIT_EXPECT_EQ(test, contains_ex, 1);
                        KUNIT_EXPECT_EQ(test, ext4_ext_pblock(ex), es_pblk);
                        KUNIT_EXPECT_EQ(test, 1,
                                        (exp_ext.is_unwrit &&
                                         ext4_es_is_unwritten(&es)) ||
                                                (!exp_ext.is_unwrit &&
                                                 ext4_es_is_written(&es)));
                }

                /* Only printed on failure */
                kunit_log(KERN_INFO, test,
                          "# [extent %d] exp: lblk:%d len:%d unwrit:%d \n", i,
                          exp_ext.ex_lblk, exp_ext.ex_len, exp_ext.is_unwrit);
                kunit_log(KERN_INFO, test,
                          "# [extent %d] got: lblk:%d len:%d unwrit:%d\n", i,
                          le32_to_cpu(ex->ee_block),
                          ext4_ext_get_actual_len(ex),
                          ext4_ext_is_unwritten(ex));
                if (es_check_needed)
                        kunit_log(
                                KERN_INFO, test,
                                "# [extent %d] es: lblk:%d len:%d pblk:%lld type:0x%x\n",
                                i, es.es_lblk, es.es_len, ext4_es_pblock(&es),
                                ext4_es_type(&es));
                kunit_log(KERN_INFO, test, "------------------\n");

                ex = ex + 1;
        }

        if (!param->is_zeroout_test)
                return;

        /*
         * Check that then data area has been zeroed out correctly
         */
        for (int i = 0; i < param->nr_exp_data_segs; i++) {
                loff_t off, len;
                struct kunit_ext_data_state exp_data_seg = param->exp_data_state[i];

                off = exp_data_seg.off_blk << blkbits;
                len = exp_data_seg.len_blk << blkbits;
                KUNIT_EXPECT_EQ_MSG(test, 0,
                                    check_buffer(k_ctx.k_data + off,
                                                 exp_data_seg.exp_char, len),
                                    "# corruption in byte range [%lld, %lld)",
                                    off, len);
        }

        return;
}

static const struct kunit_ext_test_param test_split_convert_params[] = {
        /* unwrit to writ splits */
        { .desc = "split unwrit extent to 2 extents and convert 1st half writ",
          .type = TEST_SPLIT_CONVERT,
          .is_unwrit_at_start = 1,
          .split_flags = EXT4_GET_BLOCKS_CONVERT,
          .split_map = { .m_lblk = EXT_DATA_LBLK, .m_len = 1 },
          .nr_exp_ext = 2,
          .exp_ext_state = { { .ex_lblk = EXT_DATA_LBLK,
                               .ex_len = 1,
                               .is_unwrit = 0 },
                             { .ex_lblk = EXT_DATA_LBLK + 1,
                               .ex_len = EXT_DATA_LEN - 1,
                               .is_unwrit = 1 } },
          .is_zeroout_test = 0 },
        { .desc = "split unwrit extent to 2 extents and convert 2nd half writ",
          .type = TEST_SPLIT_CONVERT,
          .is_unwrit_at_start = 1,
          .split_flags = EXT4_GET_BLOCKS_CONVERT,
          .split_map = { .m_lblk = EXT_DATA_LBLK + 1, .m_len = EXT_DATA_LEN - 1 },
          .nr_exp_ext = 2,
          .exp_ext_state = { { .ex_lblk = EXT_DATA_LBLK,
                               .ex_len = 1,
                               .is_unwrit = 1 },
                             { .ex_lblk = EXT_DATA_LBLK + 1,
                               .ex_len = EXT_DATA_LEN - 1,
                               .is_unwrit = 0 } },
          .is_zeroout_test = 0 },
        { .desc = "split unwrit extent to 3 extents and convert 2nd half to writ",
          .type = TEST_SPLIT_CONVERT,
          .is_unwrit_at_start = 1,
          .split_flags = EXT4_GET_BLOCKS_CONVERT,
          .split_map = { .m_lblk = EXT_DATA_LBLK + 1, .m_len = EXT_DATA_LEN - 2 },
          .nr_exp_ext = 3,
          .exp_ext_state = { { .ex_lblk = EXT_DATA_LBLK,
                               .ex_len = 1,
                               .is_unwrit = 1 },
                             { .ex_lblk = EXT_DATA_LBLK + 1,
                               .ex_len = EXT_DATA_LEN - 2,
                               .is_unwrit = 0 },
                             { .ex_lblk = EXT_DATA_LBLK + 1 + (EXT_DATA_LEN - 2),
                               .ex_len = 1,
                               .is_unwrit = 1 } },
          .is_zeroout_test = 0 },

        /* writ to unwrit splits */
        { .desc = "split writ extent to 2 extents and convert 1st half unwrit",
          .type = TEST_SPLIT_CONVERT,
          .is_unwrit_at_start = 0,
          .split_flags = EXT4_GET_BLOCKS_CONVERT_UNWRITTEN,
          .split_map = { .m_lblk = EXT_DATA_LBLK, .m_len = 1 },
          .nr_exp_ext = 2,
          .exp_ext_state = { { .ex_lblk = EXT_DATA_LBLK,
                               .ex_len = 1,
                               .is_unwrit = 1 },
                             { .ex_lblk = EXT_DATA_LBLK + 1,
                               .ex_len = EXT_DATA_LEN - 1,
                               .is_unwrit = 0 } },
          .is_zeroout_test = 0 },
        { .desc = "split writ extent to 2 extents and convert 2nd half unwrit",
          .type = TEST_SPLIT_CONVERT,
          .is_unwrit_at_start = 0,
          .split_flags = EXT4_GET_BLOCKS_CONVERT_UNWRITTEN,
          .split_map = { .m_lblk = EXT_DATA_LBLK + 1, .m_len = EXT_DATA_LEN - 1 },
          .nr_exp_ext = 2,
          .exp_ext_state = { { .ex_lblk = EXT_DATA_LBLK,
                               .ex_len = 1,
                               .is_unwrit = 0 },
                             { .ex_lblk = EXT_DATA_LBLK + 1,
                               .ex_len = EXT_DATA_LEN - 1,
                               .is_unwrit = 1 } },
          .is_zeroout_test = 0 },
        { .desc = "split writ extent to 3 extents and convert 2nd half to unwrit",
          .type = TEST_SPLIT_CONVERT,
          .is_unwrit_at_start = 0,
          .split_flags = EXT4_GET_BLOCKS_CONVERT_UNWRITTEN,
          .split_map = { .m_lblk = EXT_DATA_LBLK + 1, .m_len = EXT_DATA_LEN - 2 },
          .nr_exp_ext = 3,
          .exp_ext_state = { { .ex_lblk = EXT_DATA_LBLK,
                               .ex_len = 1,
                               .is_unwrit = 0 },
                             { .ex_lblk = EXT_DATA_LBLK + 1,
                               .ex_len = EXT_DATA_LEN - 2,
                               .is_unwrit = 1 },
                             { .ex_lblk = EXT_DATA_LBLK + 1 + (EXT_DATA_LEN - 2),
                               .ex_len = 1,
                               .is_unwrit = 0 } },
          .is_zeroout_test = 0 },

        /*
         * ***** zeroout tests *****
         */
        /* unwrit to writ splits */
        { .desc = "split unwrit extent to 2 extents and convert 1st half writ (zeroout)",
          .type = TEST_SPLIT_CONVERT,
          .is_unwrit_at_start = 1,
          .split_flags = EXT4_GET_BLOCKS_CONVERT,
          .split_map = { .m_lblk = EXT_DATA_LBLK, .m_len = 1 },
          .nr_exp_ext = 1,
          .exp_ext_state = { { .ex_lblk = EXT_DATA_LBLK,
                               .ex_len = EXT_DATA_LEN,
                               .is_unwrit = 0 } },
          .is_zeroout_test = 1,
          .nr_exp_data_segs = 2,
          .exp_data_state = { { .exp_char = 'X', .off_blk = 0, .len_blk = 1 },
                              { .exp_char = 0,
                                .off_blk = 1,
                                .len_blk = EXT_DATA_LEN - 1 } } },
        { .desc = "split unwrit extent to 2 extents and convert 2nd half writ (zeroout)",
          .type = TEST_SPLIT_CONVERT,
          .is_unwrit_at_start = 1,
          .split_flags = EXT4_GET_BLOCKS_CONVERT,
          .split_map = { .m_lblk = EXT_DATA_LBLK + 1, .m_len = EXT_DATA_LEN - 1 },
          .nr_exp_ext = 1,
          .exp_ext_state = { { .ex_lblk = EXT_DATA_LBLK,
                               .ex_len = EXT_DATA_LEN,
                               .is_unwrit = 0 } },
          .is_zeroout_test = 1,
          .nr_exp_data_segs = 2,
          .exp_data_state = { { .exp_char = 0, .off_blk = 0, .len_blk = 1 },
                              { .exp_char = 'X',
                                .off_blk = 1,
                                .len_blk = EXT_DATA_LEN - 1 } } },
        { .desc = "split unwrit extent to 3 extents and convert 2nd half writ (zeroout)",
          .type = TEST_SPLIT_CONVERT,
          .is_unwrit_at_start = 1,
          .split_flags = EXT4_GET_BLOCKS_CONVERT,
          .split_map = { .m_lblk = EXT_DATA_LBLK + 1, .m_len = EXT_DATA_LEN - 2 },
          .nr_exp_ext = 1,
          .exp_ext_state = { { .ex_lblk = EXT_DATA_LBLK,
                               .ex_len = EXT_DATA_LEN,
                               .is_unwrit = 0 } },
          .is_zeroout_test = 1,
          .nr_exp_data_segs = 3,
          .exp_data_state = { { .exp_char = 0, .off_blk = 0, .len_blk = 1 },
                              { .exp_char = 'X', .off_blk = 1, .len_blk = EXT_DATA_LEN - 2 },
                              { .exp_char = 0, .off_blk = EXT_DATA_LEN - 1, .len_blk = 1 } } },

        /* writ to unwrit splits */
        { .desc = "split writ extent to 2 extents and convert 1st half unwrit (zeroout)",
          .type = TEST_SPLIT_CONVERT,
          .is_unwrit_at_start = 0,
          .split_flags = EXT4_GET_BLOCKS_CONVERT_UNWRITTEN,
          .split_map = { .m_lblk = EXT_DATA_LBLK, .m_len = 1 },
          .nr_exp_ext = 1,
          .exp_ext_state = { { .ex_lblk = EXT_DATA_LBLK,
                               .ex_len = EXT_DATA_LEN,
                               .is_unwrit = 0 } },
          .is_zeroout_test = 1,
          .nr_exp_data_segs = 2,
          .exp_data_state = { { .exp_char = 0, .off_blk = 0, .len_blk = 1 },
                              { .exp_char = 'X',
                                .off_blk = 1,
                                .len_blk = EXT_DATA_LEN - 1 } } },
        { .desc = "split writ extent to 2 extents and convert 2nd half unwrit (zeroout)",
          .type = TEST_SPLIT_CONVERT,
          .is_unwrit_at_start = 0,
          .split_flags = EXT4_GET_BLOCKS_CONVERT_UNWRITTEN,
          .split_map = { .m_lblk = EXT_DATA_LBLK + 1, .m_len = EXT_DATA_LEN - 1 },
          .nr_exp_ext = 1,
          .exp_ext_state = { { .ex_lblk = EXT_DATA_LBLK,
                               .ex_len = EXT_DATA_LEN,
                               .is_unwrit = 0 } },
          .is_zeroout_test = 1,
          .nr_exp_data_segs = 2,
          .exp_data_state = { { .exp_char = 'X', .off_blk = 0, .len_blk = 1 },
                              { .exp_char = 0,
                                .off_blk = 1,
                                .len_blk = EXT_DATA_LEN - 1 } } },
        { .desc = "split writ extent to 3 extents and convert 2nd half unwrit (zeroout)",
          .type = TEST_SPLIT_CONVERT,
          .is_unwrit_at_start = 0,
          .split_flags = EXT4_GET_BLOCKS_CONVERT_UNWRITTEN,
          .split_map = { .m_lblk = EXT_DATA_LBLK + 1, .m_len = EXT_DATA_LEN - 2 },
          .nr_exp_ext = 1,
          .exp_ext_state = { { .ex_lblk = EXT_DATA_LBLK,
                               .ex_len = EXT_DATA_LEN,
                               .is_unwrit = 0 } },
          .is_zeroout_test = 1,
          .nr_exp_data_segs = 3,
          .exp_data_state = { { .exp_char = 'X', .off_blk = 0, .len_blk = 1 },
                              { .exp_char = 0,
                                .off_blk = 1,
                                .len_blk = EXT_DATA_LEN - 2 },
                              { .exp_char = 'X',
                                .off_blk = EXT_DATA_LEN - 1,
                                .len_blk = 1 } } },
};

/* Tests to trigger ext4_ext_map_blocks() -> convert_initialized_extent() */
static const struct kunit_ext_test_param test_convert_initialized_params[] = {
        /* writ to unwrit splits */
        { .desc = "split writ extent to 2 extents and convert 1st half unwrit",
          .type = TEST_CREATE_BLOCKS,
          .split_flags = EXT4_GET_BLOCKS_CONVERT_UNWRITTEN,
          .is_unwrit_at_start = 0,
          .split_map = { .m_lblk = EXT_DATA_LBLK, .m_len = 1 },
          .nr_exp_ext = 2,
          .exp_ext_state = { { .ex_lblk = EXT_DATA_LBLK,
                               .ex_len = 1,
                               .is_unwrit = 1 },
                             { .ex_lblk = EXT_DATA_LBLK + 1,
                               .ex_len = EXT_DATA_LEN - 1,
                               .is_unwrit = 0 } },
          .is_zeroout_test = 0 },
        { .desc = "split writ extent to 2 extents and convert 2nd half unwrit",
          .type = TEST_CREATE_BLOCKS,
          .split_flags = EXT4_GET_BLOCKS_CONVERT_UNWRITTEN,
          .is_unwrit_at_start = 0,
          .split_map = { .m_lblk = EXT_DATA_LBLK + 1, .m_len = EXT_DATA_LEN - 1 },
          .nr_exp_ext = 2,
          .exp_ext_state = { { .ex_lblk = EXT_DATA_LBLK,
                               .ex_len = 1,
                               .is_unwrit = 0 },
                             { .ex_lblk = EXT_DATA_LBLK + 1,
                               .ex_len = EXT_DATA_LEN - 1,
                               .is_unwrit = 1 } },
          .is_zeroout_test = 0 },
        { .desc = "split writ extent to 3 extents and convert 2nd half to unwrit",
          .type = TEST_CREATE_BLOCKS,
          .split_flags = EXT4_GET_BLOCKS_CONVERT_UNWRITTEN,
          .is_unwrit_at_start = 0,
          .split_map = { .m_lblk = EXT_DATA_LBLK + 1, .m_len = EXT_DATA_LEN - 2 },
          .nr_exp_ext = 3,
          .exp_ext_state = { { .ex_lblk = EXT_DATA_LBLK,
                               .ex_len = 1,
                               .is_unwrit = 0 },
                             { .ex_lblk = EXT_DATA_LBLK + 1,
                               .ex_len = EXT_DATA_LEN - 2,
                               .is_unwrit = 1 },
                             { .ex_lblk = EXT_DATA_LBLK + 1 + (EXT_DATA_LEN - 2),
                               .ex_len = 1,
                               .is_unwrit = 0 } },
          .is_zeroout_test = 0 },

        /* writ to unwrit splits (zeroout) */
        { .desc = "split writ extent to 2 extents and convert 1st half unwrit (zeroout)",
          .type = TEST_CREATE_BLOCKS,
          .is_unwrit_at_start = 0,
          .split_flags = EXT4_GET_BLOCKS_CONVERT_UNWRITTEN,
          .split_map = { .m_lblk = EXT_DATA_LBLK, .m_len = 1 },
          .nr_exp_ext = 1,
          .exp_ext_state = { { .ex_lblk = EXT_DATA_LBLK,
                               .ex_len = EXT_DATA_LEN,
                               .is_unwrit = 0 } },
          .is_zeroout_test = 1,
          .nr_exp_data_segs = 2,
          .exp_data_state = { { .exp_char = 0, .off_blk = 0, .len_blk = 1 },
                              { .exp_char = 'X',
                                .off_blk = 1,
                                .len_blk = EXT_DATA_LEN - 1 } } },
        { .desc = "split writ extent to 2 extents and convert 2nd half unwrit (zeroout)",
          .type = TEST_CREATE_BLOCKS,
          .is_unwrit_at_start = 0,
          .split_flags = EXT4_GET_BLOCKS_CONVERT_UNWRITTEN,
          .split_map = { .m_lblk = EXT_DATA_LBLK + 1, .m_len = EXT_DATA_LEN - 1 },
          .nr_exp_ext = 1,
          .exp_ext_state = { { .ex_lblk = EXT_DATA_LBLK,
                               .ex_len = EXT_DATA_LEN,
                               .is_unwrit = 0 } },
          .is_zeroout_test = 1,
          .nr_exp_data_segs = 2,
          .exp_data_state = { { .exp_char = 'X', .off_blk = 0, .len_blk = 1 },
                              { .exp_char = 0,
                                .off_blk = 1,
                                .len_blk = EXT_DATA_LEN - 1 } } },
        { .desc = "split writ extent to 3 extents and convert 2nd half unwrit (zeroout)",
          .type = TEST_CREATE_BLOCKS,
          .is_unwrit_at_start = 0,
          .split_flags = EXT4_GET_BLOCKS_CONVERT_UNWRITTEN,
          .split_map = { .m_lblk = EXT_DATA_LBLK + 1, .m_len = EXT_DATA_LEN - 2 },
          .nr_exp_ext = 1,
          .exp_ext_state = { { .ex_lblk = EXT_DATA_LBLK,
                               .ex_len = EXT_DATA_LEN,
                               .is_unwrit = 0 } },
          .is_zeroout_test = 1,
          .nr_exp_data_segs = 3,
          .exp_data_state = { { .exp_char = 'X', .off_blk = 0, .len_blk = 1 },
                              { .exp_char = 0,
                                .off_blk = 1,
                                .len_blk = EXT_DATA_LEN - 2 },
                              { .exp_char = 'X',
                                .off_blk = EXT_DATA_LEN - 1,
                                .len_blk = 1 } } },
};

/* Tests to trigger ext4_ext_map_blocks() -> ext4_ext_handle_unwritten_exntents() */
static const struct kunit_ext_test_param test_handle_unwritten_params[] = {
        /* unwrit to writ splits via endio path */
        { .desc = "split unwrit extent to 2 extents and convert 1st half writ (endio)",
          .type = TEST_CREATE_BLOCKS,
          .is_unwrit_at_start = 1,
          .split_flags = EXT4_GET_BLOCKS_CONVERT,
          .split_map = { .m_lblk = EXT_DATA_LBLK, .m_len = 1 },
          .nr_exp_ext = 2,
          .exp_ext_state = { { .ex_lblk = EXT_DATA_LBLK,
                               .ex_len = 1,
                               .is_unwrit = 0 },
                             { .ex_lblk = EXT_DATA_LBLK + 1,
                               .ex_len = EXT_DATA_LEN - 1,
                               .is_unwrit = 1 } },
          .is_zeroout_test = 0 },
        { .desc = "split unwrit extent to 2 extents and convert 2nd half writ (endio)",
          .type = TEST_CREATE_BLOCKS,
          .is_unwrit_at_start = 1,
          .split_flags = EXT4_GET_BLOCKS_CONVERT,
          .split_map = { .m_lblk = EXT_DATA_LBLK + 1, .m_len = EXT_DATA_LEN - 1 },
          .nr_exp_ext = 2,
          .exp_ext_state = { { .ex_lblk = EXT_DATA_LBLK,
                               .ex_len = 1,
                               .is_unwrit = 1 },
                             { .ex_lblk = EXT_DATA_LBLK + 1,
                               .ex_len = EXT_DATA_LEN - 1,
                               .is_unwrit = 0 } },
          .is_zeroout_test = 0 },
        { .desc = "split unwrit extent to 3 extents and convert 2nd half to writ (endio)",
          .type = TEST_CREATE_BLOCKS,
          .is_unwrit_at_start = 1,
          .split_flags = EXT4_GET_BLOCKS_CONVERT,
          .split_map = { .m_lblk = EXT_DATA_LBLK + 1, .m_len = EXT_DATA_LEN - 2 },
          .nr_exp_ext = 3,
          .exp_ext_state = { { .ex_lblk = EXT_DATA_LBLK,
                               .ex_len = 1,
                               .is_unwrit = 1 },
                             { .ex_lblk = EXT_DATA_LBLK + 1,
                               .ex_len = EXT_DATA_LEN - 2,
                               .is_unwrit = 0 },
                             { .ex_lblk = EXT_DATA_LBLK + 1 + (EXT_DATA_LEN - 2),
                               .ex_len = 1,
                               .is_unwrit = 1 } },
          .is_zeroout_test = 0 },

        /* unwrit to writ splits via non-endio path */
        { .desc = "split unwrit extent to 2 extents and convert 1st half writ (non endio)",
          .type = TEST_CREATE_BLOCKS,
          .is_unwrit_at_start = 1,
          .split_flags = EXT4_GET_BLOCKS_CREATE,
          .split_map = { .m_lblk = EXT_DATA_LBLK, .m_len = 1 },
          .nr_exp_ext = 2,
          .disable_zeroout = true,
          .exp_ext_state = { { .ex_lblk = EXT_DATA_LBLK,
                               .ex_len = 1,
                               .is_unwrit = 0 },
                             { .ex_lblk = EXT_DATA_LBLK + 1,
                               .ex_len = EXT_DATA_LEN - 1,
                               .is_unwrit = 1 } },
          .is_zeroout_test = 0 },
        { .desc = "split unwrit extent to 2 extents and convert 2nd half writ (non endio)",
          .type = TEST_CREATE_BLOCKS,
          .is_unwrit_at_start = 1,
          .split_flags = EXT4_GET_BLOCKS_CREATE,
          .split_map = { .m_lblk = EXT_DATA_LBLK + 1, .m_len = EXT_DATA_LEN - 1 },
          .nr_exp_ext = 2,
          .disable_zeroout = true,
          .exp_ext_state = { { .ex_lblk = EXT_DATA_LBLK,
                               .ex_len = 1,
                               .is_unwrit = 1 },
                             { .ex_lblk = EXT_DATA_LBLK + 1,
                               .ex_len = EXT_DATA_LEN - 1,
                               .is_unwrit = 0 } },
          .is_zeroout_test = 0 },
        { .desc = "split unwrit extent to 3 extents and convert 2nd half to writ (non endio)",
          .type = TEST_CREATE_BLOCKS,
          .is_unwrit_at_start = 1,
          .split_flags = EXT4_GET_BLOCKS_CREATE,
          .split_map = { .m_lblk = EXT_DATA_LBLK + 1, .m_len = EXT_DATA_LEN - 2 },
          .nr_exp_ext = 3,
          .disable_zeroout = true,
          .exp_ext_state = { { .ex_lblk = EXT_DATA_LBLK,
                               .ex_len = 1,
                               .is_unwrit = 1 },
                             { .ex_lblk = EXT_DATA_LBLK + 1,
                               .ex_len = EXT_DATA_LEN - 2,
                               .is_unwrit = 0 },
                             { .ex_lblk = EXT_DATA_LBLK + 1 + (EXT_DATA_LEN - 2),
                               .ex_len = 1,
                               .is_unwrit = 1 } },
          .is_zeroout_test = 0 },

        /*
         * ***** zeroout tests *****
         */
        /* unwrit to writ splits (endio)*/
        { .desc = "split unwrit extent to 2 extents and convert 1st half writ (endio, zeroout)",
          .type = TEST_CREATE_BLOCKS,
          .is_unwrit_at_start = 1,
          .split_flags = EXT4_GET_BLOCKS_CONVERT,
          .split_map = { .m_lblk = EXT_DATA_LBLK, .m_len = 1 },
          .nr_exp_ext = 1,
          .exp_ext_state = { { .ex_lblk = EXT_DATA_LBLK,
                               .ex_len = EXT_DATA_LEN,
                               .is_unwrit = 0 } },
          .is_zeroout_test = 1,
          .nr_exp_data_segs = 2,
          .exp_data_state = { { .exp_char = 'X', .off_blk = 0, .len_blk = 1 },
                              { .exp_char = 0,
                                .off_blk = 1,
                                .len_blk = EXT_DATA_LEN - 1 } } },
        { .desc = "split unwrit extent to 2 extents and convert 2nd half writ (endio, zeroout)",
          .type = TEST_CREATE_BLOCKS,
          .is_unwrit_at_start = 1,
          .split_flags = EXT4_GET_BLOCKS_CONVERT,
          .split_map = { .m_lblk = EXT_DATA_LBLK + 1, .m_len = EXT_DATA_LEN - 1 },
          .nr_exp_ext = 1,
          .exp_ext_state = { { .ex_lblk = EXT_DATA_LBLK,
                               .ex_len = EXT_DATA_LEN,
                               .is_unwrit = 0 } },
          .is_zeroout_test = 1,
          .nr_exp_data_segs = 2,
          .exp_data_state = { { .exp_char = 0, .off_blk = 0, .len_blk = 1 },
                              { .exp_char = 'X',
                                .off_blk = 1,
                                .len_blk = EXT_DATA_LEN - 1 } } },
        { .desc = "split unwrit extent to 3 extents and convert 2nd half writ (endio, zeroout)",
          .type = TEST_CREATE_BLOCKS,
          .is_unwrit_at_start = 1,
          .split_flags = EXT4_GET_BLOCKS_CONVERT,
          .split_map = { .m_lblk = EXT_DATA_LBLK + 1, .m_len = EXT_DATA_LEN - 2 },
          .nr_exp_ext = 1,
          .exp_ext_state = { { .ex_lblk = EXT_DATA_LBLK,
                               .ex_len = EXT_DATA_LEN,
                               .is_unwrit = 0 } },
          .is_zeroout_test = 1,
          .nr_exp_data_segs = 3,
          .exp_data_state = { { .exp_char = 0, .off_blk = 0, .len_blk = 1 },
                              { .exp_char = 'X',
                                .off_blk = 1,
                                .len_blk = EXT_DATA_LEN - 2 },
                              { .exp_char = 0,
                                .off_blk = EXT_DATA_LEN - 1,
                                .len_blk = 1 } } },

        /* unwrit to writ splits (non-endio)*/
        { .desc = "split unwrit extent to 2 extents and convert 1st half writ (non-endio, zeroout)",
          .type = TEST_CREATE_BLOCKS,
          .is_unwrit_at_start = 1,
          .split_flags = EXT4_GET_BLOCKS_CREATE,
          .split_map = { .m_lblk = EXT_DATA_LBLK, .m_len = 1 },
          .nr_exp_ext = 1,
          .exp_ext_state = { { .ex_lblk = EXT_DATA_LBLK,
                               .ex_len = EXT_DATA_LEN,
                               .is_unwrit = 0 } },
          .is_zeroout_test = 1,
          .nr_exp_data_segs = 2,
          .exp_data_state = { { .exp_char = 'X', .off_blk = 0, .len_blk = 1 },
                              { .exp_char = 0,
                                .off_blk = 1,
                                .len_blk = EXT_DATA_LEN - 1 } } },
        { .desc = "split unwrit extent to 2 extents and convert 2nd half writ (non-endio, zeroout)",
          .type = TEST_CREATE_BLOCKS,
          .is_unwrit_at_start = 1,
          .split_flags = EXT4_GET_BLOCKS_CREATE,
          .split_map = { .m_lblk = EXT_DATA_LBLK + 1, .m_len = EXT_DATA_LEN - 1 },
          .nr_exp_ext = 1,
          .exp_ext_state = { { .ex_lblk = EXT_DATA_LBLK,
                               .ex_len = EXT_DATA_LEN,
                               .is_unwrit = 0 } },
          .is_zeroout_test = 1,
          .nr_exp_data_segs = 2,
          .exp_data_state = { { .exp_char = 0, .off_blk = 0, .len_blk = 1 },
                              { .exp_char = 'X',
                                .off_blk = 1,
                                .len_blk = EXT_DATA_LEN - 1 } } },
        { .desc = "split unwrit extent to 3 extents and convert 2nd half writ (non-endio, zeroout)",
          .type = TEST_CREATE_BLOCKS,
          .is_unwrit_at_start = 1,
          .split_flags = EXT4_GET_BLOCKS_CREATE,
          .split_map = { .m_lblk = EXT_DATA_LBLK + 1, .m_len = EXT_DATA_LEN - 2 },
          .nr_exp_ext = 1,
          .exp_ext_state = { { .ex_lblk = EXT_DATA_LBLK,
                               .ex_len = EXT_DATA_LEN,
                               .is_unwrit = 0 } },
          .is_zeroout_test = 1,
          .nr_exp_data_segs = 3,
          .exp_data_state = { { .exp_char = 0, .off_blk = 0, .len_blk = 1 },
                              { .exp_char = 'X',
                                .off_blk = 1,
                                .len_blk = EXT_DATA_LEN - 2 },
                              { .exp_char = 0,
                                .off_blk = EXT_DATA_LEN - 1,
                                .len_blk = 1 } } },
};

static void ext_get_desc(struct kunit *test, const void *p, char *desc)

{
        struct kunit_ext_test_param *param = (struct kunit_ext_test_param *)p;

        snprintf(desc, KUNIT_PARAM_DESC_SIZE, "%s %s\n", param->desc,
                 (param->type & TEST_CREATE_BLOCKS) ? "(highlevel)" : "");
}

static int test_split_convert_param_init(struct kunit *test)
{
        size_t arr_size = ARRAY_SIZE(test_split_convert_params);

        kunit_register_params_array(test, test_split_convert_params, arr_size,
                                    ext_get_desc);
        return 0;
}

static int test_convert_initialized_param_init(struct kunit *test)
{
        size_t arr_size = ARRAY_SIZE(test_convert_initialized_params);

        kunit_register_params_array(test, test_convert_initialized_params,
                                    arr_size, ext_get_desc);
        return 0;
}

static int test_handle_unwritten_init(struct kunit *test)
{
        size_t arr_size = ARRAY_SIZE(test_handle_unwritten_params);

        kunit_register_params_array(test, test_handle_unwritten_params,
                                    arr_size, ext_get_desc);
        return 0;
}

/*
 * Note that we use KUNIT_CASE_PARAM_WITH_INIT() instead of the more compact
 * KUNIT_ARRAY_PARAM() because the later currently has a limitation causing the
 * output parsing to be prone to error. For more context:
 *
 * https://lore.kernel.org/linux-kselftest/aULJpTvJDw9ctUDe@li-dc0c254c-257c-11b2-a85c-98b6c1322444.ibm.com/
 */
static struct kunit_case extents_test_cases[] = {
        KUNIT_CASE_PARAM_WITH_INIT(test_split_convert, kunit_array_gen_params,
                                   test_split_convert_param_init, NULL),
        KUNIT_CASE_PARAM_WITH_INIT(test_split_convert, kunit_array_gen_params,
                                   test_convert_initialized_param_init, NULL),
        KUNIT_CASE_PARAM_WITH_INIT(test_split_convert, kunit_array_gen_params,
                                   test_handle_unwritten_init, NULL),
        {}
};

static struct kunit_suite extents_test_suite = {
        .name = "ext4_extents_test",
        .init = extents_kunit_init,
        .exit = extents_kunit_exit,
        .test_cases = extents_test_cases,
};

kunit_test_suites(&extents_test_suite);

MODULE_LICENSE("GPL");