// SPDX-License-Identifier: GPL-2.0
/*
 *  linux/fs/hfs/brec.c
 *
 * Copyright (C) 2001
 * Brad Boyer (flar@allandria.com)
 * (C) 2003 Ardis Technologies <roman@ardistech.com>
 *
 * Handle individual btree records
 */

#include "btree.h"

static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd);
static int hfs_brec_update_parent(struct hfs_find_data *fd);
static int hfs_btree_inc_height(struct hfs_btree *tree);

/* Get the length and offset of the given record in the given node */
u16 hfs_brec_lenoff(struct hfs_bnode *node, u16 rec, u16 *off)
{
        __be16 retval[2];
        u16 dataoff;

        dataoff = node->tree->node_size - (rec + 2) * 2;
        hfs_bnode_read(node, retval, dataoff, 4);
        *off = be16_to_cpu(retval[1]);
        return be16_to_cpu(retval[0]) - *off;
}

/* Get the length of the key from a keyed record */
u16 hfs_brec_keylen(struct hfs_bnode *node, u16 rec)
{
        u16 retval, recoff;

        if (node->type != HFS_NODE_INDEX && node->type != HFS_NODE_LEAF)
                return 0;

        if ((node->type == HFS_NODE_INDEX) &&
           !(node->tree->attributes & HFS_TREE_VARIDXKEYS)) {
                if (node->tree->attributes & HFS_TREE_BIGKEYS)
                        retval = node->tree->max_key_len + 2;
                else
                        retval = node->tree->max_key_len + 1;
        } else {
                recoff = hfs_bnode_read_u16(node, node->tree->node_size - (rec + 1) * 2);
                if (!recoff)
                        return 0;
                if (node->tree->attributes & HFS_TREE_BIGKEYS) {
                        retval = hfs_bnode_read_u16(node, recoff) + 2;
                        if (retval > node->tree->max_key_len + 2) {
                                pr_err("keylen %d too large\n", retval);
                                retval = 0;
                        }
                } else {
                        retval = (hfs_bnode_read_u8(node, recoff) | 1) + 1;
                        if (retval > node->tree->max_key_len + 1) {
                                pr_err("keylen %d too large\n", retval);
                                retval = 0;
                        }
                }
        }
        return retval;
}

int hfs_brec_insert(struct hfs_find_data *fd, void *entry, int entry_len)
{
        struct hfs_btree *tree;
        struct hfs_bnode *node, *new_node;
        int size, key_len, rec;
        int data_off, end_off;
        int idx_rec_off, data_rec_off, end_rec_off;
        __be32 cnid;

        tree = fd->tree;
        if (!fd->bnode) {
                if (!tree->root)
                        hfs_btree_inc_height(tree);
                node = hfs_bnode_find(tree, tree->leaf_head);
                if (IS_ERR(node))
                        return PTR_ERR(node);
                fd->bnode = node;
                fd->record = -1;
        }
        new_node = NULL;
        key_len = (fd->search_key->key_len | 1) + 1;
again:
        /* new record idx and complete record size */
        rec = fd->record + 1;
        size = key_len + entry_len;

        node = fd->bnode;
        hfs_bnode_dump(node);
        /* get last offset */
        end_rec_off = tree->node_size - (node->num_recs + 1) * 2;
        end_off = hfs_bnode_read_u16(node, end_rec_off);
        end_rec_off -= 2;
        hfs_dbg(BNODE_MOD, "insert_rec: %d, %d, %d, %d\n",
                rec, size, end_off, end_rec_off);
        if (size > end_rec_off - end_off) {
                if (new_node)
                        panic("not enough room!\n");
                new_node = hfs_bnode_split(fd);
                if (IS_ERR(new_node))
                        return PTR_ERR(new_node);
                goto again;
        }
        if (node->type == HFS_NODE_LEAF) {
                tree->leaf_count++;
                mark_inode_dirty(tree->inode);
        }
        node->num_recs++;
        /* write new last offset */
        hfs_bnode_write_u16(node, offsetof(struct hfs_bnode_desc, num_recs), node->num_recs);
        hfs_bnode_write_u16(node, end_rec_off, end_off + size);
        data_off = end_off;
        data_rec_off = end_rec_off + 2;
        idx_rec_off = tree->node_size - (rec + 1) * 2;
        if (idx_rec_off == data_rec_off)
                goto skip;
        /* move all following entries */
        do {
                data_off = hfs_bnode_read_u16(node, data_rec_off + 2);
                hfs_bnode_write_u16(node, data_rec_off, data_off + size);
                data_rec_off += 2;
        } while (data_rec_off < idx_rec_off);

        /* move data away */
        hfs_bnode_move(node, data_off + size, data_off,
                       end_off - data_off);

skip:
        hfs_bnode_write(node, fd->search_key, data_off, key_len);
        hfs_bnode_write(node, entry, data_off + key_len, entry_len);
        hfs_bnode_dump(node);

        /*
         * update parent key if we inserted a key
         * at the start of the node and it is not the new node
         */
        if (!rec && new_node != node) {
                hfs_bnode_read_key(node, fd->search_key, data_off + size);
                hfs_brec_update_parent(fd);
        }

        if (new_node) {
                hfs_bnode_put(fd->bnode);
                if (!new_node->parent) {
                        hfs_btree_inc_height(tree);
                        new_node->parent = tree->root;
                }
                fd->bnode = hfs_bnode_find(tree, new_node->parent);

                /* create index data entry */
                cnid = cpu_to_be32(new_node->this);
                entry = &cnid;
                entry_len = sizeof(cnid);

                /* get index key */
                hfs_bnode_read_key(new_node, fd->search_key, 14);
                __hfs_brec_find(fd->bnode, fd);

                hfs_bnode_put(new_node);
                new_node = NULL;

                if (tree->attributes & HFS_TREE_VARIDXKEYS)
                        key_len = fd->search_key->key_len + 1;
                else {
                        fd->search_key->key_len = tree->max_key_len;
                        key_len = tree->max_key_len + 1;
                }
                goto again;
        }

        return 0;
}

int hfs_brec_remove(struct hfs_find_data *fd)
{
        struct hfs_btree *tree;
        struct hfs_bnode *node, *parent;
        int end_off, rec_off, data_off, size;

        tree = fd->tree;
        node = fd->bnode;
again:
        rec_off = tree->node_size - (fd->record + 2) * 2;
        end_off = tree->node_size - (node->num_recs + 1) * 2;

        if (node->type == HFS_NODE_LEAF) {
                tree->leaf_count--;
                mark_inode_dirty(tree->inode);
        }
        hfs_bnode_dump(node);
        hfs_dbg(BNODE_MOD, "remove_rec: %d, %d\n",
                fd->record, fd->keylength + fd->entrylength);
        if (!--node->num_recs) {
                hfs_bnode_unlink(node);
                if (!node->parent)
                        return 0;
                parent = hfs_bnode_find(tree, node->parent);
                if (IS_ERR(parent))
                        return PTR_ERR(parent);
                hfs_bnode_put(node);
                node = fd->bnode = parent;

                __hfs_brec_find(node, fd);
                goto again;
        }
        hfs_bnode_write_u16(node, offsetof(struct hfs_bnode_desc, num_recs), node->num_recs);

        if (rec_off == end_off)
                goto skip;
        size = fd->keylength + fd->entrylength;

        do {
                data_off = hfs_bnode_read_u16(node, rec_off);
                hfs_bnode_write_u16(node, rec_off + 2, data_off - size);
                rec_off -= 2;
        } while (rec_off >= end_off);

        /* fill hole */
        hfs_bnode_move(node, fd->keyoffset, fd->keyoffset + size,
                       data_off - fd->keyoffset - size);
skip:
        hfs_bnode_dump(node);
        if (!fd->record)
                hfs_brec_update_parent(fd);
        return 0;
}

static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd)
{
        struct hfs_btree *tree;
        struct hfs_bnode *node, *new_node, *next_node;
        struct hfs_bnode_desc node_desc;
        int num_recs, new_rec_off, new_off, old_rec_off;
        int data_start, data_end, size;

        tree = fd->tree;
        node = fd->bnode;
        new_node = hfs_bmap_alloc(tree);
        if (IS_ERR(new_node))
                return new_node;
        hfs_bnode_get(node);
        hfs_dbg(BNODE_MOD, "split_nodes: %d - %d - %d\n",
                node->this, new_node->this, node->next);
        new_node->next = node->next;
        new_node->prev = node->this;
        new_node->parent = node->parent;
        new_node->type = node->type;
        new_node->height = node->height;

        if (node->next)
                next_node = hfs_bnode_find(tree, node->next);
        else
                next_node = NULL;

        if (IS_ERR(next_node)) {
                hfs_bnode_put(node);
                hfs_bnode_put(new_node);
                return next_node;
        }

        size = tree->node_size / 2 - node->num_recs * 2 - 14;
        old_rec_off = tree->node_size - 4;
        num_recs = 1;
        for (;;) {
                data_start = hfs_bnode_read_u16(node, old_rec_off);
                if (data_start > size)
                        break;
                old_rec_off -= 2;
                if (++num_recs < node->num_recs)
                        continue;
                /* panic? */
                hfs_bnode_put(node);
                hfs_bnode_put(new_node);
                if (next_node)
                        hfs_bnode_put(next_node);
                return ERR_PTR(-ENOSPC);
        }

        if (fd->record + 1 < num_recs) {
                /* new record is in the lower half,
                 * so leave some more space there
                 */
                old_rec_off += 2;
                num_recs--;
                data_start = hfs_bnode_read_u16(node, old_rec_off);
        } else {
                hfs_bnode_put(node);
                hfs_bnode_get(new_node);
                fd->bnode = new_node;
                fd->record -= num_recs;
                fd->keyoffset -= data_start - 14;
                fd->entryoffset -= data_start - 14;
        }
        new_node->num_recs = node->num_recs - num_recs;
        node->num_recs = num_recs;

        new_rec_off = tree->node_size - 2;
        new_off = 14;
        size = data_start - new_off;
        num_recs = new_node->num_recs;
        data_end = data_start;
        while (num_recs) {
                hfs_bnode_write_u16(new_node, new_rec_off, new_off);
                old_rec_off -= 2;
                new_rec_off -= 2;
                data_end = hfs_bnode_read_u16(node, old_rec_off);
                new_off = data_end - size;
                num_recs--;
        }
        hfs_bnode_write_u16(new_node, new_rec_off, new_off);
        hfs_bnode_copy(new_node, 14, node, data_start, data_end - data_start);

        /* update new bnode header */
        node_desc.next = cpu_to_be32(new_node->next);
        node_desc.prev = cpu_to_be32(new_node->prev);
        node_desc.type = new_node->type;
        node_desc.height = new_node->height;
        node_desc.num_recs = cpu_to_be16(new_node->num_recs);
        node_desc.reserved = 0;
        hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));

        /* update previous bnode header */
        node->next = new_node->this;
        hfs_bnode_read(node, &node_desc, 0, sizeof(node_desc));
        node_desc.next = cpu_to_be32(node->next);
        node_desc.num_recs = cpu_to_be16(node->num_recs);
        hfs_bnode_write(node, &node_desc, 0, sizeof(node_desc));

        /* update next bnode header */
        if (next_node) {
                next_node->prev = new_node->this;
                hfs_bnode_read(next_node, &node_desc, 0, sizeof(node_desc));
                node_desc.prev = cpu_to_be32(next_node->prev);
                hfs_bnode_write(next_node, &node_desc, 0, sizeof(node_desc));
                hfs_bnode_put(next_node);
        } else if (node->this == tree->leaf_tail) {
                /* if there is no next node, this might be the new tail */
                tree->leaf_tail = new_node->this;
                mark_inode_dirty(tree->inode);
        }

        hfs_bnode_dump(node);
        hfs_bnode_dump(new_node);
        hfs_bnode_put(node);

        return new_node;
}

static int hfs_brec_update_parent(struct hfs_find_data *fd)
{
        struct hfs_btree *tree;
        struct hfs_bnode *node, *new_node, *parent;
        int newkeylen, diff;
        int rec, rec_off, end_rec_off;
        int start_off, end_off;

        tree = fd->tree;
        node = fd->bnode;
        new_node = NULL;
        if (!node->parent)
                return 0;

again:
        parent = hfs_bnode_find(tree, node->parent);
        if (IS_ERR(parent))
                return PTR_ERR(parent);
        __hfs_brec_find(parent, fd);
        if (fd->record < 0)
                return -ENOENT;
        hfs_bnode_dump(parent);
        rec = fd->record;

        /* size difference between old and new key */
        if (tree->attributes & HFS_TREE_VARIDXKEYS)
                newkeylen = (hfs_bnode_read_u8(node, 14) | 1) + 1;
        else
                fd->keylength = newkeylen = tree->max_key_len + 1;
        hfs_dbg(BNODE_MOD, "update_rec: %d, %d, %d\n",
                rec, fd->keylength, newkeylen);

        rec_off = tree->node_size - (rec + 2) * 2;
        end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
        diff = newkeylen - fd->keylength;
        if (!diff)
                goto skip;
        if (diff > 0) {
                end_off = hfs_bnode_read_u16(parent, end_rec_off);
                if (end_rec_off - end_off < diff) {

                        printk(KERN_DEBUG "splitting index node...\n");
                        fd->bnode = parent;
                        new_node = hfs_bnode_split(fd);
                        if (IS_ERR(new_node))
                                return PTR_ERR(new_node);
                        parent = fd->bnode;
                        rec = fd->record;
                        rec_off = tree->node_size - (rec + 2) * 2;
                        end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
                }
        }

        end_off = start_off = hfs_bnode_read_u16(parent, rec_off);
        hfs_bnode_write_u16(parent, rec_off, start_off + diff);
        start_off -= 4; /* move previous cnid too */

        while (rec_off > end_rec_off) {
                rec_off -= 2;
                end_off = hfs_bnode_read_u16(parent, rec_off);
                hfs_bnode_write_u16(parent, rec_off, end_off + diff);
        }
        hfs_bnode_move(parent, start_off + diff, start_off,
                       end_off - start_off);
skip:
        hfs_bnode_copy(parent, fd->keyoffset, node, 14, newkeylen);
        if (!(tree->attributes & HFS_TREE_VARIDXKEYS))
                hfs_bnode_write_u8(parent, fd->keyoffset, newkeylen - 1);
        hfs_bnode_dump(parent);

        hfs_bnode_put(node);
        node = parent;

        if (new_node) {
                __be32 cnid;

                if (!new_node->parent) {
                        hfs_btree_inc_height(tree);
                        new_node->parent = tree->root;
                }
                fd->bnode = hfs_bnode_find(tree, new_node->parent);
                /* create index key and entry */
                hfs_bnode_read_key(new_node, fd->search_key, 14);
                cnid = cpu_to_be32(new_node->this);

                __hfs_brec_find(fd->bnode, fd);
                hfs_brec_insert(fd, &cnid, sizeof(cnid));
                hfs_bnode_put(fd->bnode);
                hfs_bnode_put(new_node);

                if (!rec) {
                        if (new_node == node)
                                goto out;
                        /* restore search_key */
                        hfs_bnode_read_key(node, fd->search_key, 14);
                }
                new_node = NULL;
        }

        if (!rec && node->parent)
                goto again;
out:
        fd->bnode = node;
        return 0;
}

static int hfs_btree_inc_height(struct hfs_btree *tree)
{
        struct hfs_bnode *node, *new_node;
        struct hfs_bnode_desc node_desc;
        int key_size, rec;
        __be32 cnid;

        node = NULL;
        if (tree->root) {
                node = hfs_bnode_find(tree, tree->root);
                if (IS_ERR(node))
                        return PTR_ERR(node);
        }
        new_node = hfs_bmap_alloc(tree);
        if (IS_ERR(new_node)) {
                hfs_bnode_put(node);
                return PTR_ERR(new_node);
        }

        tree->root = new_node->this;
        if (!tree->depth) {
                tree->leaf_head = tree->leaf_tail = new_node->this;
                new_node->type = HFS_NODE_LEAF;
                new_node->num_recs = 0;
        } else {
                new_node->type = HFS_NODE_INDEX;
                new_node->num_recs = 1;
        }
        new_node->parent = 0;
        new_node->next = 0;
        new_node->prev = 0;
        new_node->height = ++tree->depth;

        node_desc.next = cpu_to_be32(new_node->next);
        node_desc.prev = cpu_to_be32(new_node->prev);
        node_desc.type = new_node->type;
        node_desc.height = new_node->height;
        node_desc.num_recs = cpu_to_be16(new_node->num_recs);
        node_desc.reserved = 0;
        hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));

        rec = tree->node_size - 2;
        hfs_bnode_write_u16(new_node, rec, 14);

        if (node) {
                /* insert old root idx into new root */
                node->parent = tree->root;
                if (node->type == HFS_NODE_LEAF ||
                    tree->attributes & HFS_TREE_VARIDXKEYS)
                        key_size = hfs_bnode_read_u8(node, 14) + 1;
                else
                        key_size = tree->max_key_len + 1;
                hfs_bnode_copy(new_node, 14, node, 14, key_size);

                if (!(tree->attributes & HFS_TREE_VARIDXKEYS)) {
                        key_size = tree->max_key_len + 1;
                        hfs_bnode_write_u8(new_node, 14, tree->max_key_len);
                }
                key_size = (key_size + 1) & -2;
                cnid = cpu_to_be32(node->this);
                hfs_bnode_write(new_node, &cnid, 14 + key_size, 4);

                rec -= 2;
                hfs_bnode_write_u16(new_node, rec, 14 + key_size + 4);

                hfs_bnode_put(node);
        }
        hfs_bnode_put(new_node);
        mark_inode_dirty(tree->inode);

        return 0;
}