// SPDX-License-Identifier: GPL-2.0

  /*
   *  linux/fs/hfsplus/brec.c
   *
   * Copyright (C) 2001
   * Brad Boyer (flar@allandria.com)
   * (C) 2003 Ardis Technologies <roman@ardistech.com>
   *
   * Handle individual btree records
   */
  
  #include "hfsplus_fs.h"
  #include "hfsplus_raw.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 *);
  
  /* 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) &&
  	   (node->tree->cnid != HFSPLUS_ATTR_CNID)) {

  		retval = node->tree->max_key_len + 2;
  	} else {

  		recoff = hfs_bnode_read_u16(node,
  			node->tree->node_size - (rec + 1) * 2);

  		if (!recoff)
  			return 0;

  		if (recoff > node->tree->node_size - 2) {

  			pr_err("recoff %d too large
  ", recoff);

  			return 0;
  		}

  
  		retval = hfs_bnode_read_u16(node, recoff) + 2;
  		if (retval > node->tree->max_key_len + 2) {

  			pr_err("keylen %d too large
  ",

  				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 = be16_to_cpu(fd->search_key->key_len) + 2;
  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
  ",

  		rec, size, end_off, end_rec_off);

  	if (size > end_rec_off - end_off) {
  		if (new_node)
  			panic("not enough room!
  ");
  		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_find_rec_by_key);

  
  		hfs_bnode_put(new_node);
  		new_node = NULL;

  		if ((tree->attributes & HFS_TREE_VARIDXKEYS) ||
  				(tree->cnid == HFSPLUS_ATTR_CNID))

  			key_len = be16_to_cpu(fd->search_key->key_len) + 2;
  		else {

  			fd->search_key->key_len =
  				cpu_to_be16(tree->max_key_len);

  			key_len = tree->max_key_len + 2;
  		}
  		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
  ",

  		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, hfs_find_rec_by_key);

  		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
  ",

  		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, hfs_find_rec_by_key);

  	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) ||
  				(tree->cnid == HFSPLUS_ATTR_CNID))

  		newkeylen = hfs_bnode_read_u16(node, 14) + 2;
  	else
  		fd->keylength = newkeylen = tree->max_key_len + 2;

  	hfs_dbg(BNODE_MOD, "update_rec: %d, %d, %d
  ",

  		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) {

  			hfs_dbg(BNODE_MOD, "splitting index node
  ");

  			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);
  	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_find_rec_by_key);

  		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 ||
  				tree->cnid == HFSPLUS_ATTR_CNID)

  			key_size = hfs_bnode_read_u16(node, 14) + 2;
  		else
  			key_size = tree->max_key_len + 2;
  		hfs_bnode_copy(new_node, 14, node, 14, key_size);

  		if (!(tree->attributes & HFS_TREE_VARIDXKEYS) &&
  				(tree->cnid != HFSPLUS_ATTR_CNID)) {

  			key_size = tree->max_key_len + 2;
  			hfs_bnode_write_u16(new_node, 14, tree->max_key_len);
  		}
  		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;
  }