// SPDX-License-Identifier: GPL-2.0
#include <linux/sizes.h>
#include "btrfs-tests.h"
#include "../transaction.h"
#include "../delayed-ref.h"
#include "../extent-tree.h"

#define FAKE_ROOT_OBJECTID 256
#define FAKE_BYTENR 0
#define FAKE_LEVEL 1
#define FAKE_INO 256
#define FAKE_FILE_OFFSET 0
#define FAKE_PARENT SZ_1M

struct ref_head_check {
        u64 bytenr;
        u64 num_bytes;
        int ref_mod;
        int total_ref_mod;
        int must_insert;
};

struct ref_node_check {
        u64 bytenr;
        u64 num_bytes;
        int ref_mod;
        enum btrfs_delayed_ref_action action;
        u8 type;
        u64 parent;
        u64 root;
        u64 owner;
        u64 offset;
};

static enum btrfs_ref_type ref_type_from_disk_ref_type(u8 type)
{
        if ((type == BTRFS_TREE_BLOCK_REF_KEY) ||
            (type == BTRFS_SHARED_BLOCK_REF_KEY))
                return BTRFS_REF_METADATA;
        return BTRFS_REF_DATA;
}

static void delete_delayed_ref_head(struct btrfs_trans_handle *trans,
                                    struct btrfs_delayed_ref_head *head)
{
        struct btrfs_fs_info *fs_info = trans->fs_info;
        struct btrfs_delayed_ref_root *delayed_refs =
                &trans->transaction->delayed_refs;

        spin_lock(&delayed_refs->lock);
        spin_lock(&head->lock);
        btrfs_delete_ref_head(fs_info, delayed_refs, head);
        spin_unlock(&head->lock);
        spin_unlock(&delayed_refs->lock);

        btrfs_delayed_ref_unlock(head);
        btrfs_put_delayed_ref_head(head);
}

static void delete_delayed_ref_node(struct btrfs_delayed_ref_head *head,
                                    struct btrfs_delayed_ref_node *node)
{
        rb_erase_cached(&node->ref_node, &head->ref_tree);
        RB_CLEAR_NODE(&node->ref_node);
        if (!list_empty(&node->add_list))
                list_del_init(&node->add_list);
        btrfs_put_delayed_ref(node);
}

static int validate_ref_head(struct btrfs_delayed_ref_head *head,
                             struct ref_head_check *check)
{
        if (head->bytenr != check->bytenr) {
                test_err("invalid bytenr have: %llu want: %llu", head->bytenr,
                         check->bytenr);
                return -EINVAL;
        }

        if (head->num_bytes != check->num_bytes) {
                test_err("invalid num_bytes have: %llu want: %llu",
                         head->num_bytes, check->num_bytes);
                return -EINVAL;
        }

        if (head->ref_mod != check->ref_mod) {
                test_err("invalid ref_mod have: %d want: %d", head->ref_mod,
                         check->ref_mod);
                return -EINVAL;
        }

        if (head->total_ref_mod != check->total_ref_mod) {
                test_err("invalid total_ref_mod have: %d want: %d",
                         head->total_ref_mod, check->total_ref_mod);
                return -EINVAL;
        }

        if (head->must_insert_reserved != check->must_insert) {
                test_err("invalid must_insert have: %d want: %d",
                         head->must_insert_reserved, check->must_insert);
                return -EINVAL;
        }

        return 0;
}

static int validate_ref_node(struct btrfs_delayed_ref_node *node,
                             struct ref_node_check *check)
{
        if (node->bytenr != check->bytenr) {
                test_err("invalid bytenr have: %llu want: %llu", node->bytenr,
                         check->bytenr);
                return -EINVAL;
        }

        if (node->num_bytes != check->num_bytes) {
                test_err("invalid num_bytes have: %llu want: %llu",
                         node->num_bytes, check->num_bytes);
                return -EINVAL;
        }

        if (node->ref_mod != check->ref_mod) {
                test_err("invalid ref_mod have: %d want: %d", node->ref_mod,
                         check->ref_mod);
                return -EINVAL;
        }

        if (node->action != check->action) {
                test_err("invalid action have: %d want: %d", node->action,
                         check->action);
                return -EINVAL;
        }

        if (node->parent != check->parent) {
                test_err("invalid parent have: %llu want: %llu", node->parent,
                         check->parent);
                return -EINVAL;
        }

        if (node->ref_root != check->root) {
                test_err("invalid root have: %llu want: %llu", node->ref_root,
                         check->root);
                return -EINVAL;
        }

        if (node->type != check->type) {
                test_err("invalid type have: %d want: %d", node->type,
                         check->type);
                return -EINVAL;
        }

        if (btrfs_delayed_ref_owner(node) != check->owner) {
                test_err("invalid owner have: %llu want: %llu",
                         btrfs_delayed_ref_owner(node), check->owner);
                return -EINVAL;
        }

        if (btrfs_delayed_ref_offset(node) != check->offset) {
                test_err("invalid offset have: %llu want: %llu",
                         btrfs_delayed_ref_offset(node), check->offset);
                return -EINVAL;
        }

        return 0;
}

static int simple_test(struct btrfs_trans_handle *trans,
                       struct ref_head_check *head_check,
                       struct ref_node_check *node_check)
{
        struct btrfs_delayed_ref_root *delayed_refs =
                &trans->transaction->delayed_refs;
        struct btrfs_fs_info *fs_info = trans->fs_info;
        struct btrfs_delayed_ref_head *head;
        struct btrfs_delayed_ref_node *node;
        struct btrfs_ref ref = {
                .type = ref_type_from_disk_ref_type(node_check->type),
                .action = node_check->action,
                .parent = node_check->parent,
                .ref_root = node_check->root,
                .bytenr = node_check->bytenr,
                .num_bytes = fs_info->nodesize,
        };
        int ret;

        if (ref.type == BTRFS_REF_METADATA)
                btrfs_init_tree_ref(&ref, node_check->owner, node_check->root,
                                    false);
        else
                btrfs_init_data_ref(&ref, node_check->owner, node_check->offset,
                                    node_check->root, true);

        if (ref.type == BTRFS_REF_METADATA)
                ret = btrfs_add_delayed_tree_ref(trans, &ref, NULL);
        else
                ret = btrfs_add_delayed_data_ref(trans, &ref, 0);
        if (ret) {
                test_err("failed ref action %d", ret);
                return ret;
        }

        head = btrfs_select_ref_head(fs_info, delayed_refs);
        if (IS_ERR_OR_NULL(head)) {
                if (IS_ERR(head))
                        test_err("failed to select delayed ref head: %ld",
                                 PTR_ERR(head));
                else
                        test_err("failed to find delayed ref head");
                return -EINVAL;
        }

        ret = -EINVAL;
        if (validate_ref_head(head, head_check))
                goto out;

        spin_lock(&head->lock);
        node = btrfs_select_delayed_ref(head);
        spin_unlock(&head->lock);
        if (!node) {
                test_err("failed to select delayed ref");
                goto out;
        }

        if (validate_ref_node(node, node_check))
                goto out;
        ret = 0;
out:
        btrfs_unselect_ref_head(delayed_refs, head);
        btrfs_destroy_delayed_refs(trans->transaction);
        return ret;
}

/*
 * These are simple tests, make sure that our btrfs_ref's get turned into the
 * appropriate btrfs_delayed_ref_node based on their settings and action.
 */
static int simple_tests(struct btrfs_trans_handle *trans)
{
        struct btrfs_fs_info *fs_info = trans->fs_info;
        struct ref_head_check head_check = {
                .bytenr = FAKE_BYTENR,
                .num_bytes = fs_info->nodesize,
                .ref_mod = 1,
                .total_ref_mod = 1,
        };
        struct ref_node_check node_check = {
                .bytenr = FAKE_BYTENR,
                .num_bytes = fs_info->nodesize,
                .ref_mod = 1,
                .action = BTRFS_ADD_DELAYED_REF,
                .type = BTRFS_TREE_BLOCK_REF_KEY,
                .parent = 0,
                .root = FAKE_ROOT_OBJECTID,
                .owner = FAKE_LEVEL,
                .offset = 0,
        };

        if (simple_test(trans, &head_check, &node_check)) {
                test_err("single add tree block failed");
                return -EINVAL;
        }

        node_check.type = BTRFS_EXTENT_DATA_REF_KEY;
        node_check.owner = FAKE_INO;
        node_check.offset = FAKE_FILE_OFFSET;

        if (simple_test(trans, &head_check, &node_check)) {
                test_err("single add extent data failed");
                return -EINVAL;
        }

        node_check.parent = FAKE_PARENT;
        node_check.type = BTRFS_SHARED_BLOCK_REF_KEY;
        node_check.owner = FAKE_LEVEL;
        node_check.offset = 0;

        if (simple_test(trans, &head_check, &node_check)) {
                test_err("single add shared block failed");
                return -EINVAL;
        }

        node_check.type = BTRFS_SHARED_DATA_REF_KEY;
        node_check.owner = FAKE_INO;
        node_check.offset = FAKE_FILE_OFFSET;

        if (simple_test(trans, &head_check, &node_check)) {
                test_err("single add shared data failed");
                return -EINVAL;
        }

        head_check.ref_mod = -1;
        head_check.total_ref_mod = -1;
        node_check.action = BTRFS_DROP_DELAYED_REF;
        node_check.type = BTRFS_TREE_BLOCK_REF_KEY;
        node_check.owner = FAKE_LEVEL;
        node_check.offset = 0;
        node_check.parent = 0;

        if (simple_test(trans, &head_check, &node_check)) {
                test_err("single drop tree block failed");
                return -EINVAL;
        }

        node_check.type = BTRFS_EXTENT_DATA_REF_KEY;
        node_check.owner = FAKE_INO;
        node_check.offset = FAKE_FILE_OFFSET;

        if (simple_test(trans, &head_check, &node_check)) {
                test_err("single drop extent data failed");
                return -EINVAL;
        }

        node_check.parent = FAKE_PARENT;
        node_check.type = BTRFS_SHARED_BLOCK_REF_KEY;
        node_check.owner = FAKE_LEVEL;
        node_check.offset = 0;
        if (simple_test(trans, &head_check, &node_check)) {
                test_err("single drop shared block failed");
                return -EINVAL;
        }

        node_check.type = BTRFS_SHARED_DATA_REF_KEY;
        node_check.owner = FAKE_INO;
        node_check.offset = FAKE_FILE_OFFSET;
        if (simple_test(trans, &head_check, &node_check)) {
                test_err("single drop shared data failed");
                return -EINVAL;
        }

        return 0;
}

/*
 * Merge tests, validate that we do delayed ref merging properly, the ref counts
 * all end up properly, and delayed refs are deleted once they're no longer
 * needed.
 */
static int merge_tests(struct btrfs_trans_handle *trans,
                       enum btrfs_ref_type type)
{
        struct btrfs_fs_info *fs_info = trans->fs_info;
        struct btrfs_delayed_ref_head *head = NULL;
        struct btrfs_delayed_ref_node *node;
        struct btrfs_ref ref = {
                .type = type,
                .action = BTRFS_ADD_DELAYED_REF,
                .parent = 0,
                .ref_root = FAKE_ROOT_OBJECTID,
                .bytenr = FAKE_BYTENR,
                .num_bytes = fs_info->nodesize,
        };
        struct ref_head_check head_check = {
                .bytenr = FAKE_BYTENR,
                .num_bytes = fs_info->nodesize,
                .ref_mod = 0,
                .total_ref_mod = 0,
        };
        struct ref_node_check node_check = {
                .bytenr = FAKE_BYTENR,
                .num_bytes = fs_info->nodesize,
                .ref_mod = 2,
                .action = BTRFS_ADD_DELAYED_REF,
                .parent = 0,
                .root = FAKE_ROOT_OBJECTID,
        };
        int ret;

        /*
         * First add a ref and then drop it, make sure we get a head ref with a
         * 0 total ref mod and no nodes.
         */
        if (type == BTRFS_REF_METADATA) {
                node_check.type = BTRFS_TREE_BLOCK_REF_KEY;
                node_check.owner = FAKE_LEVEL;
                btrfs_init_tree_ref(&ref, FAKE_LEVEL, FAKE_ROOT_OBJECTID, false);
        } else {
                node_check.type = BTRFS_EXTENT_DATA_REF_KEY;
                node_check.owner = FAKE_INO;
                node_check.offset = FAKE_FILE_OFFSET;
                btrfs_init_data_ref(&ref, FAKE_INO, FAKE_FILE_OFFSET,
                                    FAKE_ROOT_OBJECTID, true);
        }

        if (type == BTRFS_REF_METADATA)
                ret = btrfs_add_delayed_tree_ref(trans, &ref, NULL);
        else
                ret = btrfs_add_delayed_data_ref(trans, &ref, 0);
        if (ret) {
                test_err("failed ref action %d", ret);
                return ret;
        }

        ref.action = BTRFS_DROP_DELAYED_REF;
        if (type == BTRFS_REF_METADATA)
                ret = btrfs_add_delayed_tree_ref(trans, &ref, NULL);
        else
                ret = btrfs_add_delayed_data_ref(trans, &ref, 0);
        if (ret) {
                test_err("failed ref action %d", ret);
                goto out;
        }

        head = btrfs_select_ref_head(fs_info, &trans->transaction->delayed_refs);
        if (IS_ERR_OR_NULL(head)) {
                if (IS_ERR(head))
                        test_err("failed to select delayed ref head: %ld",
                                 PTR_ERR(head));
                else
                        test_err("failed to find delayed ref head");
                goto out;
        }

        ret = -EINVAL;
        if (validate_ref_head(head, &head_check)) {
                test_err("single add and drop failed");
                goto out;
        }

        spin_lock(&head->lock);
        node = btrfs_select_delayed_ref(head);
        spin_unlock(&head->lock);
        if (node) {
                test_err("found node when none should exist");
                goto out;
        }

        delete_delayed_ref_head(trans, head);
        head = NULL;

        /*
         * Add a ref, then add another ref, make sure we get a head ref with a
         * 2 total ref mod and 1 node.
         */
        ref.action = BTRFS_ADD_DELAYED_REF;
        if (type == BTRFS_REF_METADATA)
                ret = btrfs_add_delayed_tree_ref(trans, &ref, NULL);
        else
                ret = btrfs_add_delayed_data_ref(trans, &ref, 0);
        if (ret) {
                test_err("failed ref action %d", ret);
                goto out;
        }

        if (type == BTRFS_REF_METADATA)
                ret = btrfs_add_delayed_tree_ref(trans, &ref, NULL);
        else
                ret = btrfs_add_delayed_data_ref(trans, &ref, 0);
        if (ret) {
                test_err("failed ref action %d", ret);
                goto out;
        }

        head = btrfs_select_ref_head(fs_info, &trans->transaction->delayed_refs);
        if (IS_ERR_OR_NULL(head)) {
                if (IS_ERR(head))
                        test_err("failed to select delayed ref head: %ld",
                                 PTR_ERR(head));
                else
                        test_err("failed to find delayed ref head");
                goto out;
        }

        head_check.ref_mod = 2;
        head_check.total_ref_mod = 2;
        ret = -EINVAL;
        if (validate_ref_head(head, &head_check)) {
                test_err("double add failed");
                goto out;
        }

        spin_lock(&head->lock);
        node = btrfs_select_delayed_ref(head);
        spin_unlock(&head->lock);
        if (!node) {
                test_err("failed to select delayed ref");
                goto out;
        }

        if (validate_ref_node(node, &node_check)) {
                test_err("node check failed");
                goto out;
        }

        delete_delayed_ref_node(head, node);

        spin_lock(&head->lock);
        node = btrfs_select_delayed_ref(head);
        spin_unlock(&head->lock);
        if (node) {
                test_err("found node when none should exist");
                goto out;
        }
        delete_delayed_ref_head(trans, head);
        head = NULL;

        /* Add two drop refs, make sure they are merged properly. */
        ref.action = BTRFS_DROP_DELAYED_REF;
        if (type == BTRFS_REF_METADATA)
                ret = btrfs_add_delayed_tree_ref(trans, &ref, NULL);
        else
                ret = btrfs_add_delayed_data_ref(trans, &ref, 0);
        if (ret) {
                test_err("failed ref action %d", ret);
                goto out;
        }

        if (type == BTRFS_REF_METADATA)
                ret = btrfs_add_delayed_tree_ref(trans, &ref, NULL);
        else
                ret = btrfs_add_delayed_data_ref(trans, &ref, 0);
        if (ret) {
                test_err("failed ref action %d", ret);
                goto out;
        }

        head = btrfs_select_ref_head(fs_info, &trans->transaction->delayed_refs);
        if (IS_ERR_OR_NULL(head)) {
                if (IS_ERR(head))
                        test_err("failed to select delayed ref head: %ld",
                                 PTR_ERR(head));
                else
                        test_err("failed to find delayed ref head");
                goto out;
        }

        head_check.ref_mod = -2;
        head_check.total_ref_mod = -2;
        ret = -EINVAL;
        if (validate_ref_head(head, &head_check)) {
                test_err("double drop failed");
                goto out;
        }

        node_check.action = BTRFS_DROP_DELAYED_REF;
        spin_lock(&head->lock);
        node = btrfs_select_delayed_ref(head);
        spin_unlock(&head->lock);
        if (!node) {
                test_err("failed to select delayed ref");
                goto out;
        }

        if (validate_ref_node(node, &node_check)) {
                test_err("node check failed");
                goto out;
        }

        delete_delayed_ref_node(head, node);

        spin_lock(&head->lock);
        node = btrfs_select_delayed_ref(head);
        spin_unlock(&head->lock);
        if (node) {
                test_err("found node when none should exist");
                goto out;
        }
        delete_delayed_ref_head(trans, head);
        head = NULL;

        /* Add multiple refs, then drop until we go negative again. */
        ref.action = BTRFS_ADD_DELAYED_REF;
        for (int i = 0; i < 10; i++) {
                if (type == BTRFS_REF_METADATA)
                        ret = btrfs_add_delayed_tree_ref(trans, &ref, NULL);
                else
                        ret = btrfs_add_delayed_data_ref(trans, &ref, 0);
                if (ret) {
                        test_err("failed ref action %d", ret);
                        goto out;
                }
        }

        ref.action = BTRFS_DROP_DELAYED_REF;
        for (int i = 0; i < 12; i++) {
                if (type == BTRFS_REF_METADATA)
                        ret = btrfs_add_delayed_tree_ref(trans, &ref, NULL);
                else
                        ret = btrfs_add_delayed_data_ref(trans, &ref, 0);
                if (ret) {
                        test_err("failed ref action %d", ret);
                        goto out;
                }
        }

        head = btrfs_select_ref_head(fs_info, &trans->transaction->delayed_refs);
        if (IS_ERR_OR_NULL(head)) {
                if (IS_ERR(head))
                        test_err("failed to select delayed ref head: %ld",
                                 PTR_ERR(head));
                else
                        test_err("failed to find delayed ref head");
                ret = -EINVAL;
                goto out;
        }

        head_check.ref_mod = -2;
        head_check.total_ref_mod = -2;
        ret = -EINVAL;
        if (validate_ref_head(head, &head_check)) {
                test_err("double drop failed");
                goto out;
        }

        spin_lock(&head->lock);
        node = btrfs_select_delayed_ref(head);
        spin_unlock(&head->lock);
        if (!node) {
                test_err("failed to select delayed ref");
                goto out;
        }

        if (validate_ref_node(node, &node_check)) {
                test_err("node check failed");
                goto out;
        }

        delete_delayed_ref_node(head, node);

        spin_lock(&head->lock);
        node = btrfs_select_delayed_ref(head);
        spin_unlock(&head->lock);
        if (node) {
                test_err("found node when none should exist");
                goto out;
        }

        delete_delayed_ref_head(trans, head);
        head = NULL;

        /* Drop multiple refs, then add until we go positive again. */
        ref.action = BTRFS_DROP_DELAYED_REF;
        for (int i = 0; i < 10; i++) {
                if (type == BTRFS_REF_METADATA)
                        ret = btrfs_add_delayed_tree_ref(trans, &ref, NULL);
                else
                        ret = btrfs_add_delayed_data_ref(trans, &ref, 0);
                if (ret) {
                        test_err("failed ref action %d", ret);
                        goto out;
                }
        }

        ref.action = BTRFS_ADD_DELAYED_REF;
        for (int i = 0; i < 12; i++) {
                if (type == BTRFS_REF_METADATA)
                        ret = btrfs_add_delayed_tree_ref(trans, &ref, NULL);
                else
                        ret = btrfs_add_delayed_data_ref(trans, &ref, 0);
                if (ret) {
                        test_err("failed ref action %d", ret);
                        goto out;
                }
        }

        head = btrfs_select_ref_head(fs_info, &trans->transaction->delayed_refs);
        if (IS_ERR_OR_NULL(head)) {
                if (IS_ERR(head))
                        test_err("failed to select delayed ref head: %ld",
                                 PTR_ERR(head));
                else
                        test_err("failed to find delayed ref head");
                ret = -EINVAL;
                goto out;
        }

        head_check.ref_mod = 2;
        head_check.total_ref_mod = 2;
        ret = -EINVAL;
        if (validate_ref_head(head, &head_check)) {
                test_err("add and drop to positive failed");
                goto out;
        }

        node_check.action = BTRFS_ADD_DELAYED_REF;
        spin_lock(&head->lock);
        node = btrfs_select_delayed_ref(head);
        spin_unlock(&head->lock);
        if (!node) {
                test_err("failed to select delayed ref");
                goto out;
        }

        if (validate_ref_node(node, &node_check)) {
                test_err("node check failed");
                goto out;
        }

        delete_delayed_ref_node(head, node);

        spin_lock(&head->lock);
        node = btrfs_select_delayed_ref(head);
        spin_unlock(&head->lock);
        if (node) {
                test_err("found node when none should exist");
                goto out;
        }
        delete_delayed_ref_head(trans, head);
        head = NULL;

        /*
         * Add a bunch of refs with different roots and parents, then drop them
         * all, make sure everything is properly merged.
         */
        ref.action = BTRFS_ADD_DELAYED_REF;
        for (int i = 0; i < 50; i++) {
                if (!(i % 2)) {
                        ref.parent = 0;
                        ref.ref_root = FAKE_ROOT_OBJECTID + i;
                } else {
                        ref.parent = FAKE_PARENT + (i * fs_info->nodesize);
                }
                if (type == BTRFS_REF_METADATA)
                        ret = btrfs_add_delayed_tree_ref(trans, &ref, NULL);
                else
                        ret = btrfs_add_delayed_data_ref(trans, &ref, 0);
                if (ret) {
                        test_err("failed ref action %d", ret);
                        goto out;
                }
        }

        ref.action = BTRFS_DROP_DELAYED_REF;
        for (int i = 0; i < 50; i++) {
                if (!(i % 2)) {
                        ref.parent = 0;
                        ref.ref_root = FAKE_ROOT_OBJECTID + i;
                } else {
                        ref.parent = FAKE_PARENT + (i * fs_info->nodesize);
                }
                if (type == BTRFS_REF_METADATA)
                        ret = btrfs_add_delayed_tree_ref(trans, &ref, NULL);
                else
                        ret = btrfs_add_delayed_data_ref(trans, &ref, 0);
                if (ret) {
                        test_err("failed ref action %d", ret);
                        goto out;
                }
        }

        head = btrfs_select_ref_head(fs_info, &trans->transaction->delayed_refs);
        if (IS_ERR_OR_NULL(head)) {
                if (IS_ERR(head))
                        test_err("failed to select delayed ref head: %ld",
                                 PTR_ERR(head));
                else
                        test_err("failed to find delayed ref head");
                ret = -EINVAL;
                goto out;
        }

        head_check.ref_mod = 0;
        head_check.total_ref_mod = 0;
        ret = -EINVAL;
        if (validate_ref_head(head, &head_check)) {
                test_err("add and drop multiple failed");
                goto out;
        }

        spin_lock(&head->lock);
        node = btrfs_select_delayed_ref(head);
        spin_unlock(&head->lock);
        if (node) {
                test_err("found node when none should exist");
                goto out;
        }
        ret = 0;
out:
        if (!IS_ERR_OR_NULL(head))
                btrfs_unselect_ref_head(&trans->transaction->delayed_refs, head);
        btrfs_destroy_delayed_refs(trans->transaction);
        return ret;
}

/*
 * Basic test to validate we always get the add operations first followed by any
 * delete operations.
 */
static int select_delayed_refs_test(struct btrfs_trans_handle *trans)
{
        struct btrfs_delayed_ref_root *delayed_refs =
                &trans->transaction->delayed_refs;
        struct btrfs_fs_info *fs_info = trans->fs_info;
        struct btrfs_delayed_ref_head *head = NULL;
        struct btrfs_delayed_ref_node *node;
        struct btrfs_ref ref = {
                .type = BTRFS_REF_METADATA,
                .action = BTRFS_DROP_DELAYED_REF,
                .parent = 0,
                .ref_root = FAKE_ROOT_OBJECTID,
                .bytenr = FAKE_BYTENR,
                .num_bytes = fs_info->nodesize,
        };
        struct ref_head_check head_check = {
                .bytenr = FAKE_BYTENR,
                .num_bytes = fs_info->nodesize,
                .ref_mod = 0,
                .total_ref_mod = 0,
        };
        struct ref_node_check node_check = {
                .bytenr = FAKE_BYTENR,
                .num_bytes = fs_info->nodesize,
                .ref_mod = 1,
                .action = BTRFS_ADD_DELAYED_REF,
                .type = BTRFS_TREE_BLOCK_REF_KEY,
                .parent = 0,
                .owner = FAKE_LEVEL,
                .offset = 0,
        };
        int ret;

        /* Add the drop first. */
        btrfs_init_tree_ref(&ref, FAKE_LEVEL, FAKE_ROOT_OBJECTID, false);
        ret = btrfs_add_delayed_tree_ref(trans, &ref, NULL);
        if (ret) {
                test_err("failed ref action %d", ret);
                return ret;
        }

        /*
         * Now add the add, and make it a different root so it's logically later
         * in the rb tree.
         */
        ref.action = BTRFS_ADD_DELAYED_REF;
        ref.ref_root = FAKE_ROOT_OBJECTID + 1;
        ret = btrfs_add_delayed_tree_ref(trans, &ref, NULL);
        if (ret) {
                test_err("failed ref action %d", ret);
                goto out;
        }

        head = btrfs_select_ref_head(fs_info, delayed_refs);
        if (IS_ERR_OR_NULL(head)) {
                if (IS_ERR(head))
                        test_err("failed to select delayed ref head: %ld",
                                 PTR_ERR(head));
                else
                        test_err("failed to find delayed ref head");
                ret = -EINVAL;
                head = NULL;
                goto out;
        }

        ret = -EINVAL;
        if (validate_ref_head(head, &head_check)) {
                test_err("head check failed");
                goto out;
        }

        spin_lock(&head->lock);
        node = btrfs_select_delayed_ref(head);
        spin_unlock(&head->lock);
        if (!node) {
                test_err("failed to select delayed ref");
                goto out;
        }

        node_check.root = FAKE_ROOT_OBJECTID + 1;
        if (validate_ref_node(node, &node_check)) {
                test_err("node check failed");
                goto out;
        }
        delete_delayed_ref_node(head, node);

        spin_lock(&head->lock);
        node = btrfs_select_delayed_ref(head);
        spin_unlock(&head->lock);
        if (!node) {
                test_err("failed to select delayed ref");
                goto out;
        }

        node_check.action = BTRFS_DROP_DELAYED_REF;
        node_check.root = FAKE_ROOT_OBJECTID;
        if (validate_ref_node(node, &node_check)) {
                test_err("node check failed");
                goto out;
        }
        delete_delayed_ref_node(head, node);
        delete_delayed_ref_head(trans, head);
        head = NULL;

        /*
         * Now we're going to do the same thing, but we're going to have an add
         * that gets deleted because of a merge, and make sure we still have
         * another add in place.
         */
        ref.action = BTRFS_DROP_DELAYED_REF;
        ref.ref_root = FAKE_ROOT_OBJECTID;
        ret = btrfs_add_delayed_tree_ref(trans, &ref, NULL);
        if (ret) {
                test_err("failed ref action %d", ret);
                goto out;
        }

        ref.action = BTRFS_ADD_DELAYED_REF;
        ref.ref_root = FAKE_ROOT_OBJECTID + 1;
        ret = btrfs_add_delayed_tree_ref(trans, &ref, NULL);
        if (ret) {
                test_err("failed ref action %d", ret);
                goto out;
        }

        ref.action = BTRFS_DROP_DELAYED_REF;
        ret = btrfs_add_delayed_tree_ref(trans, &ref, NULL);
        if (ret) {
                test_err("failed ref action %d", ret);
                goto out;
        }

        ref.action = BTRFS_ADD_DELAYED_REF;
        ref.ref_root = FAKE_ROOT_OBJECTID + 2;
        ret = btrfs_add_delayed_tree_ref(trans, &ref, NULL);
        if (ret) {
                test_err("failed ref action %d", ret);
                goto out;
        }

        head = btrfs_select_ref_head(fs_info, delayed_refs);
        if (IS_ERR_OR_NULL(head)) {
                if (IS_ERR(head))
                        test_err("failed to select delayed ref head: %ld",
                                 PTR_ERR(head));
                else
                        test_err("failed to find delayed ref head");
                ret = -EINVAL;
                head = NULL;
                goto out;
        }

        ret = -EINVAL;
        if (validate_ref_head(head, &head_check)) {
                test_err("head check failed");
                goto out;
        }

        spin_lock(&head->lock);
        node = btrfs_select_delayed_ref(head);
        spin_unlock(&head->lock);
        if (!node) {
                test_err("failed to select delayed ref");
                goto out;
        }

        node_check.action = BTRFS_ADD_DELAYED_REF;
        node_check.root = FAKE_ROOT_OBJECTID + 2;
        if (validate_ref_node(node, &node_check)) {
                test_err("node check failed");
                goto out;
        }
        delete_delayed_ref_node(head, node);

        spin_lock(&head->lock);
        node = btrfs_select_delayed_ref(head);
        spin_unlock(&head->lock);
        if (!node) {
                test_err("failed to select delayed ref");
                goto out;
        }

        node_check.action = BTRFS_DROP_DELAYED_REF;
        node_check.root = FAKE_ROOT_OBJECTID;
        if (validate_ref_node(node, &node_check)) {
                test_err("node check failed");
                goto out;
        }
        delete_delayed_ref_node(head, node);
        ret = 0;
out:
        if (head)
                btrfs_unselect_ref_head(delayed_refs, head);
        btrfs_destroy_delayed_refs(trans->transaction);
        return ret;
}

int btrfs_test_delayed_refs(u32 sectorsize, u32 nodesize)
{
        struct btrfs_transaction *transaction;
        struct btrfs_trans_handle trans;
        struct btrfs_fs_info *fs_info;
        int ret;

        test_msg("running delayed refs tests");

        fs_info = btrfs_alloc_dummy_fs_info(nodesize, sectorsize);
        if (!fs_info) {
                test_std_err(TEST_ALLOC_FS_INFO);
                return -ENOMEM;
        }
        transaction = kmalloc_obj(*transaction);
        if (!transaction) {
                test_std_err(TEST_ALLOC_TRANSACTION);
                ret = -ENOMEM;
                goto out_free_fs_info;
        }
        btrfs_init_dummy_trans(&trans, fs_info);
        btrfs_init_dummy_transaction(transaction, fs_info);
        trans.transaction = transaction;

        ret = simple_tests(&trans);
        if (!ret) {
                test_msg("running delayed refs merge tests on metadata refs");
                ret = merge_tests(&trans, BTRFS_REF_METADATA);
        }

        if (!ret) {
                test_msg("running delayed refs merge tests on data refs");
                ret = merge_tests(&trans, BTRFS_REF_DATA);
        }

        if (!ret)
                ret = select_delayed_refs_test(&trans);

        kfree(transaction);
out_free_fs_info:
        btrfs_free_dummy_fs_info(fs_info);
        return ret;
}