[mirror_ubuntu-focal-kernel.git] / fs / hfs / bnode.c

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

#include <linux/pagemap.h>
#include <linux/slab.h>
#include <linux/swap.h>

#include "btree.h"

void hfs_bnode_read(struct hfs_bnode *node, void *buf,
		int off, int len)
{
	struct page *page;

	off += node->page_offset;
	page = node->page[0];

	memcpy(buf, kmap(page) + off, len);
	kunmap(page);
}

u16 hfs_bnode_read_u16(struct hfs_bnode *node, int off)
{
	__be16 data;
	// optimize later...
	hfs_bnode_read(node, &data, off, 2);
	return be16_to_cpu(data);
}

u8 hfs_bnode_read_u8(struct hfs_bnode *node, int off)
{
	u8 data;
	// optimize later...
	hfs_bnode_read(node, &data, off, 1);
	return data;
}

void hfs_bnode_read_key(struct hfs_bnode *node, void *key, int off)
{
	struct hfs_btree *tree;
	int key_len;

	tree = node->tree;
	if (node->type == HFS_NODE_LEAF ||
	    tree->attributes & HFS_TREE_VARIDXKEYS)
		key_len = hfs_bnode_read_u8(node, off) + 1;
	else
		key_len = tree->max_key_len + 1;

	hfs_bnode_read(node, key, off, key_len);
}

void hfs_bnode_write(struct hfs_bnode *node, void *buf, int off, int len)
{
	struct page *page;

	off += node->page_offset;
	page = node->page[0];

	memcpy(kmap(page) + off, buf, len);
	kunmap(page);
	set_page_dirty(page);
}

void hfs_bnode_write_u16(struct hfs_bnode *node, int off, u16 data)
{
	__be16 v = cpu_to_be16(data);
	// optimize later...
	hfs_bnode_write(node, &v, off, 2);
}

void hfs_bnode_write_u8(struct hfs_bnode *node, int off, u8 data)
{
	// optimize later...
	hfs_bnode_write(node, &data, off, 1);
}

void hfs_bnode_clear(struct hfs_bnode *node, int off, int len)
{
	struct page *page;

	off += node->page_offset;
	page = node->page[0];

	memset(kmap(page) + off, 0, len);
	kunmap(page);
	set_page_dirty(page);
}

void hfs_bnode_copy(struct hfs_bnode *dst_node, int dst,
		struct hfs_bnode *src_node, int src, int len)
{
	struct hfs_btree *tree;
	struct page *src_page, *dst_page;

	hfs_dbg(BNODE_MOD, "copybytes: %u,%u,%u\n", dst, src, len);
	if (!len)
		return;
	tree = src_node->tree;
	src += src_node->page_offset;
	dst += dst_node->page_offset;
	src_page = src_node->page[0];
	dst_page = dst_node->page[0];

	memcpy(kmap(dst_page) + dst, kmap(src_page) + src, len);
	kunmap(src_page);
	kunmap(dst_page);
	set_page_dirty(dst_page);
}

void hfs_bnode_move(struct hfs_bnode *node, int dst, int src, int len)
{
	struct page *page;
	void *ptr;

	hfs_dbg(BNODE_MOD, "movebytes: %u,%u,%u\n", dst, src, len);
	if (!len)
		return;
	src += node->page_offset;
	dst += node->page_offset;
	page = node->page[0];
	ptr = kmap(page);
	memmove(ptr + dst, ptr + src, len);
	kunmap(page);
	set_page_dirty(page);
}

void hfs_bnode_dump(struct hfs_bnode *node)
{
	struct hfs_bnode_desc desc;
	__be32 cnid;
	int i, off, key_off;

	hfs_dbg(BNODE_MOD, "bnode: %d\n", node->this);
	hfs_bnode_read(node, &desc, 0, sizeof(desc));
	hfs_dbg(BNODE_MOD, "%d, %d, %d, %d, %d\n",
		be32_to_cpu(desc.next), be32_to_cpu(desc.prev),
		desc.type, desc.height, be16_to_cpu(desc.num_recs));

	off = node->tree->node_size - 2;
	for (i = be16_to_cpu(desc.num_recs); i >= 0; off -= 2, i--) {
		key_off = hfs_bnode_read_u16(node, off);
		hfs_dbg_cont(BNODE_MOD, " %d", key_off);
		if (i && node->type == HFS_NODE_INDEX) {
			int tmp;

			if (node->tree->attributes & HFS_TREE_VARIDXKEYS)
				tmp = (hfs_bnode_read_u8(node, key_off) | 1) + 1;
			else
				tmp = node->tree->max_key_len + 1;
			hfs_dbg_cont(BNODE_MOD, " (%d,%d",
				     tmp, hfs_bnode_read_u8(node, key_off));
			hfs_bnode_read(node, &cnid, key_off + tmp, 4);
			hfs_dbg_cont(BNODE_MOD, ",%d)", be32_to_cpu(cnid));
		} else if (i && node->type == HFS_NODE_LEAF) {
			int tmp;

			tmp = hfs_bnode_read_u8(node, key_off);
			hfs_dbg_cont(BNODE_MOD, " (%d)", tmp);
		}
	}
	hfs_dbg_cont(BNODE_MOD, "\n");
}

void hfs_bnode_unlink(struct hfs_bnode *node)
{
	struct hfs_btree *tree;
	struct hfs_bnode *tmp;
	__be32 cnid;

	tree = node->tree;
	if (node->prev) {
		tmp = hfs_bnode_find(tree, node->prev);
		if (IS_ERR(tmp))
			return;
		tmp->next = node->next;
		cnid = cpu_to_be32(tmp->next);
		hfs_bnode_write(tmp, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
		hfs_bnode_put(tmp);
	} else if (node->type == HFS_NODE_LEAF)
		tree->leaf_head = node->next;

	if (node->next) {
		tmp = hfs_bnode_find(tree, node->next);
		if (IS_ERR(tmp))
			return;
		tmp->prev = node->prev;
		cnid = cpu_to_be32(tmp->prev);
		hfs_bnode_write(tmp, &cnid, offsetof(struct hfs_bnode_desc, prev), 4);
		hfs_bnode_put(tmp);
	} else if (node->type == HFS_NODE_LEAF)
		tree->leaf_tail = node->prev;

	// move down?
	if (!node->prev && !node->next) {
		printk(KERN_DEBUG "hfs_btree_del_level\n");
	}
	if (!node->parent) {
		tree->root = 0;
		tree->depth = 0;
	}
	set_bit(HFS_BNODE_DELETED, &node->flags);
}

static inline int hfs_bnode_hash(u32 num)
{
	num = (num >> 16) + num;
	num += num >> 8;
	return num & (NODE_HASH_SIZE - 1);
}

struct hfs_bnode *hfs_bnode_findhash(struct hfs_btree *tree, u32 cnid)
{
	struct hfs_bnode *node;

	if (cnid >= tree->node_count) {
		pr_err("request for non-existent node %d in B*Tree\n", cnid);
		return NULL;
	}

	for (node = tree->node_hash[hfs_bnode_hash(cnid)];
	     node; node = node->next_hash) {
		if (node->this == cnid) {
			return node;
		}
	}
	return NULL;
}

static struct hfs_bnode *__hfs_bnode_create(struct hfs_btree *tree, u32 cnid)
{
	struct super_block *sb;
	struct hfs_bnode *node, *node2;
	struct address_space *mapping;
	struct page *page;
	int size, block, i, hash;
	loff_t off;

	if (cnid >= tree->node_count) {
		pr_err("request for non-existent node %d in B*Tree\n", cnid);
		return NULL;
	}

	sb = tree->inode->i_sb;
	size = sizeof(struct hfs_bnode) + tree->pages_per_bnode *
		sizeof(struct page *);
	node = kzalloc(size, GFP_KERNEL);
	if (!node)
		return NULL;
	node->tree = tree;
	node->this = cnid;
	set_bit(HFS_BNODE_NEW, &node->flags);
	atomic_set(&node->refcnt, 1);
	hfs_dbg(BNODE_REFS, "new_node(%d:%d): 1\n",
		node->tree->cnid, node->this);
	init_waitqueue_head(&node->lock_wq);
	spin_lock(&tree->hash_lock);
	node2 = hfs_bnode_findhash(tree, cnid);
	if (!node2) {
		hash = hfs_bnode_hash(cnid);
		node->next_hash = tree->node_hash[hash];
		tree->node_hash[hash] = node;
		tree->node_hash_cnt++;
	} else {
		spin_unlock(&tree->hash_lock);
		kfree(node);
		wait_event(node2->lock_wq, !test_bit(HFS_BNODE_NEW, &node2->flags));
		return node2;
	}
	spin_unlock(&tree->hash_lock);

	mapping = tree->inode->i_mapping;
	off = (loff_t)cnid * tree->node_size;
	block = off >> PAGE_SHIFT;
	node->page_offset = off & ~PAGE_MASK;
	for (i = 0; i < tree->pages_per_bnode; i++) {
		page = read_mapping_page(mapping, block++, NULL);
		if (IS_ERR(page))
			goto fail;
		if (PageError(page)) {
			put_page(page);
			goto fail;
		}
		node->page[i] = page;
	}

	return node;
fail:
	set_bit(HFS_BNODE_ERROR, &node->flags);
	return node;
}

void hfs_bnode_unhash(struct hfs_bnode *node)
{
	struct hfs_bnode **p;

	hfs_dbg(BNODE_REFS, "remove_node(%d:%d): %d\n",
		node->tree->cnid, node->this, atomic_read(&node->refcnt));
	for (p = &node->tree->node_hash[hfs_bnode_hash(node->this)];
	     *p && *p != node; p = &(*p)->next_hash)
		;
	BUG_ON(!*p);
	*p = node->next_hash;
	node->tree->node_hash_cnt--;
}

/* Load a particular node out of a tree */
struct hfs_bnode *hfs_bnode_find(struct hfs_btree *tree, u32 num)
{
	struct hfs_bnode *node;
	struct hfs_bnode_desc *desc;
	int i, rec_off, off, next_off;
	int entry_size, key_size;

	spin_lock(&tree->hash_lock);
	node = hfs_bnode_findhash(tree, num);
	if (node) {
		hfs_bnode_get(node);
		spin_unlock(&tree->hash_lock);
		wait_event(node->lock_wq, !test_bit(HFS_BNODE_NEW, &node->flags));
		if (test_bit(HFS_BNODE_ERROR, &node->flags))
			goto node_error;
		return node;
	}
	spin_unlock(&tree->hash_lock);
	node = __hfs_bnode_create(tree, num);
	if (!node)
		return ERR_PTR(-ENOMEM);
	if (test_bit(HFS_BNODE_ERROR, &node->flags))
		goto node_error;
	if (!test_bit(HFS_BNODE_NEW, &node->flags))
		return node;

	desc = (struct hfs_bnode_desc *)(kmap(node->page[0]) + node->page_offset);
	node->prev = be32_to_cpu(desc->prev);
	node->next = be32_to_cpu(desc->next);
	node->num_recs = be16_to_cpu(desc->num_recs);
	node->type = desc->type;
	node->height = desc->height;
	kunmap(node->page[0]);

	switch (node->type) {
	case HFS_NODE_HEADER:
	case HFS_NODE_MAP:
		if (node->height != 0)
			goto node_error;
		break;
	case HFS_NODE_LEAF:
		if (node->height != 1)
			goto node_error;
		break;
	case HFS_NODE_INDEX:
		if (node->height <= 1 || node->height > tree->depth)
			goto node_error;
		break;
	default:
		goto node_error;
	}

	rec_off = tree->node_size - 2;
	off = hfs_bnode_read_u16(node, rec_off);
	if (off != sizeof(struct hfs_bnode_desc))
		goto node_error;
	for (i = 1; i <= node->num_recs; off = next_off, i++) {
		rec_off -= 2;
		next_off = hfs_bnode_read_u16(node, rec_off);
		if (next_off <= off ||
		    next_off > tree->node_size ||
		    next_off & 1)
			goto node_error;
		entry_size = next_off - off;
		if (node->type != HFS_NODE_INDEX &&
		    node->type != HFS_NODE_LEAF)
			continue;
		key_size = hfs_bnode_read_u8(node, off) + 1;
		if (key_size >= entry_size /*|| key_size & 1*/)
			goto node_error;
	}
	clear_bit(HFS_BNODE_NEW, &node->flags);
	wake_up(&node->lock_wq);
	return node;

node_error:
	set_bit(HFS_BNODE_ERROR, &node->flags);
	clear_bit(HFS_BNODE_NEW, &node->flags);
	wake_up(&node->lock_wq);
	hfs_bnode_put(node);
	return ERR_PTR(-EIO);
}

void hfs_bnode_free(struct hfs_bnode *node)
{
	int i;

	for (i = 0; i < node->tree->pages_per_bnode; i++)
		if (node->page[i])
			put_page(node->page[i]);
	kfree(node);
}

struct hfs_bnode *hfs_bnode_create(struct hfs_btree *tree, u32 num)
{
	struct hfs_bnode *node;
	struct page **pagep;
	int i;

	spin_lock(&tree->hash_lock);
	node = hfs_bnode_findhash(tree, num);
	spin_unlock(&tree->hash_lock);
	if (node) {
		pr_crit("new node %u already hashed?\n", num);
		WARN_ON(1);
		return node;
	}
	node = __hfs_bnode_create(tree, num);
	if (!node)
		return ERR_PTR(-ENOMEM);
	if (test_bit(HFS_BNODE_ERROR, &node->flags)) {
		hfs_bnode_put(node);
		return ERR_PTR(-EIO);
	}

	pagep = node->page;
	memset(kmap(*pagep) + node->page_offset, 0,
	       min((int)PAGE_SIZE, (int)tree->node_size));
	set_page_dirty(*pagep);
	kunmap(*pagep);
	for (i = 1; i < tree->pages_per_bnode; i++) {
		memset(kmap(*++pagep), 0, PAGE_SIZE);
		set_page_dirty(*pagep);
		kunmap(*pagep);
	}
	clear_bit(HFS_BNODE_NEW, &node->flags);
	wake_up(&node->lock_wq);

	return node;
}

void hfs_bnode_get(struct hfs_bnode *node)
{
	if (node) {
		atomic_inc(&node->refcnt);
		hfs_dbg(BNODE_REFS, "get_node(%d:%d): %d\n",
			node->tree->cnid, node->this,
			atomic_read(&node->refcnt));
	}
}

/* Dispose of resources used by a node */
void hfs_bnode_put(struct hfs_bnode *node)
{
	if (node) {
		struct hfs_btree *tree = node->tree;
		int i;

		hfs_dbg(BNODE_REFS, "put_node(%d:%d): %d\n",
			node->tree->cnid, node->this,
			atomic_read(&node->refcnt));
		BUG_ON(!atomic_read(&node->refcnt));
		if (!atomic_dec_and_lock(&node->refcnt, &tree->hash_lock))
			return;
		for (i = 0; i < tree->pages_per_bnode; i++) {
			if (!node->page[i])
				continue;
			mark_page_accessed(node->page[i]);
		}

		if (test_bit(HFS_BNODE_DELETED, &node->flags)) {
			hfs_bnode_unhash(node);
			spin_unlock(&tree->hash_lock);
			hfs_bmap_free(node);
			hfs_bnode_free(node);
			return;
		}
		spin_unlock(&tree->hash_lock);
	}
}
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
1da177e4 LT	2	/*
	3	* linux/fs/hfs/bnode.c
	4	*
	5	* Copyright (C) 2001
	6	* Brad Boyer (flar@allandria.com)
	7	* (C) 2003 Ardis Technologies <roman@ardistech.com>
	8	*
	9	* Handle basic btree node operations
	10	*/
	11
	12	#include <linux/pagemap.h>
5a0e3ad6	13	#include <linux/slab.h>
1da177e4 LT	14	#include <linux/swap.h>
	15
	16	#include "btree.h"
	17
1da177e4 LT	18	void hfs_bnode_read(struct hfs_bnode node, void buf,
	19	int off, int len)
	20	{
	21	struct page *page;
	22
	23	off += node->page_offset;
	24	page = node->page[0];
	25
	26	memcpy(buf, kmap(page) + off, len);
	27	kunmap(page);
	28	}
	29
	30	u16 hfs_bnode_read_u16(struct hfs_bnode *node, int off)
	31	{
	32	__be16 data;
	33	// optimize later...
	34	hfs_bnode_read(node, &data, off, 2);
	35	return be16_to_cpu(data);
	36	}
	37
	38	u8 hfs_bnode_read_u8(struct hfs_bnode *node, int off)
	39	{
	40	u8 data;
	41	// optimize later...
	42	hfs_bnode_read(node, &data, off, 1);
	43	return data;
	44	}
	45
	46	void hfs_bnode_read_key(struct hfs_bnode node, void key, int off)
	47	{
	48	struct hfs_btree *tree;
	49	int key_len;
	50
	51	tree = node->tree;
	52	if (node->type == HFS_NODE_LEAF \|\|
	53	tree->attributes & HFS_TREE_VARIDXKEYS)
	54	key_len = hfs_bnode_read_u8(node, off) + 1;
	55	else
	56	key_len = tree->max_key_len + 1;
	57
	58	hfs_bnode_read(node, key, off, key_len);
	59	}
	60
	61	void hfs_bnode_write(struct hfs_bnode node, void buf, int off, int len)
	62	{
	63	struct page *page;
	64
	65	off += node->page_offset;
	66	page = node->page[0];
	67
	68	memcpy(kmap(page) + off, buf, len);
	69	kunmap(page);
	70	set_page_dirty(page);
	71	}
	72
	73	void hfs_bnode_write_u16(struct hfs_bnode *node, int off, u16 data)
	74	{
	75	__be16 v = cpu_to_be16(data);
	76	// optimize later...
	77	hfs_bnode_write(node, &v, off, 2);
	78	}
	79
	80	void hfs_bnode_write_u8(struct hfs_bnode *node, int off, u8 data)
	81	{
82	// optimize later...
83	hfs_bnode_write(node, &data, off, 1);
84	}
85
86	void hfs_bnode_clear(struct hfs_bnode *node, int off, int len)
87	{
88	struct page *page;
89
90	off += node->page_offset;
91	page = node->page[0];
92
93	memset(kmap(page) + off, 0, len);
94	kunmap(page);
95	set_page_dirty(page);
96	}
97
98	void hfs_bnode_copy(struct hfs_bnode *dst_node, int dst,
99	struct hfs_bnode *src_node, int src, int len)
100	{
101	struct hfs_btree *tree;
102	struct page src_page, dst_page;
103
c2b3e1f7	104	hfs_dbg(BNODE_MOD, "copybytes: %u,%u,%u\n", dst, src, len);
1da177e4 LT	105	if (!len)
	106	return;
	107	tree = src_node->tree;
	108	src += src_node->page_offset;
	109	dst += dst_node->page_offset;
	110	src_page = src_node->page[0];
	111	dst_page = dst_node->page[0];
	112
	113	memcpy(kmap(dst_page) + dst, kmap(src_page) + src, len);
	114	kunmap(src_page);
	115	kunmap(dst_page);
	116	set_page_dirty(dst_page);
	117	}
	118
	119	void hfs_bnode_move(struct hfs_bnode *node, int dst, int src, int len)
	120	{
	121	struct page *page;
	122	void *ptr;
	123
c2b3e1f7	124	hfs_dbg(BNODE_MOD, "movebytes: %u,%u,%u\n", dst, src, len);
1da177e4 LT	125	if (!len)
	126	return;
	127	src += node->page_offset;
	128	dst += node->page_offset;
	129	page = node->page[0];
	130	ptr = kmap(page);
	131	memmove(ptr + dst, ptr + src, len);
	132	kunmap(page);
	133	set_page_dirty(page);
	134	}
	135
	136	void hfs_bnode_dump(struct hfs_bnode *node)
	137	{
	138	struct hfs_bnode_desc desc;
	139	__be32 cnid;
	140	int i, off, key_off;
	141
c2b3e1f7	142	hfs_dbg(BNODE_MOD, "bnode: %d\n", node->this);
1da177e4	143	hfs_bnode_read(node, &desc, 0, sizeof(desc));
c2b3e1f7	144	hfs_dbg(BNODE_MOD, "%d, %d, %d, %d, %d\n",
1da177e4 LT	145	be32_to_cpu(desc.next), be32_to_cpu(desc.prev),
	146	desc.type, desc.height, be16_to_cpu(desc.num_recs));
	147
	148	off = node->tree->node_size - 2;
	149	for (i = be16_to_cpu(desc.num_recs); i >= 0; off -= 2, i--) {
	150	key_off = hfs_bnode_read_u16(node, off);
c2b3e1f7	151	hfs_dbg_cont(BNODE_MOD, " %d", key_off);
1da177e4 LT	152	if (i && node->type == HFS_NODE_INDEX) {
	153	int tmp;
	154
	155	if (node->tree->attributes & HFS_TREE_VARIDXKEYS)
	156	tmp = (hfs_bnode_read_u8(node, key_off) \| 1) + 1;
	157	else
	158	tmp = node->tree->max_key_len + 1;
c2b3e1f7 JP	159	hfs_dbg_cont(BNODE_MOD, " (%d,%d",
c2b3e1f7 JP	160	tmp, hfs_bnode_read_u8(node, key_off));
1da177e4	161	hfs_bnode_read(node, &cnid, key_off + tmp, 4);
c2b3e1f7	162	hfs_dbg_cont(BNODE_MOD, ",%d)", be32_to_cpu(cnid));
1da177e4 LT	163	} else if (i && node->type == HFS_NODE_LEAF) {
	164	int tmp;
	165
	166	tmp = hfs_bnode_read_u8(node, key_off);
c2b3e1f7	167	hfs_dbg_cont(BNODE_MOD, " (%d)", tmp);
1da177e4 LT	168	}
1da177e4 LT	169	}
c2b3e1f7	170	hfs_dbg_cont(BNODE_MOD, "\n");
1da177e4 LT	171	}
	172
	173	void hfs_bnode_unlink(struct hfs_bnode *node)
	174	{
	175	struct hfs_btree *tree;
	176	struct hfs_bnode *tmp;
	177	__be32 cnid;
	178
	179	tree = node->tree;
	180	if (node->prev) {
	181	tmp = hfs_bnode_find(tree, node->prev);
	182	if (IS_ERR(tmp))
	183	return;
	184	tmp->next = node->next;
	185	cnid = cpu_to_be32(tmp->next);
	186	hfs_bnode_write(tmp, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
	187	hfs_bnode_put(tmp);
	188	} else if (node->type == HFS_NODE_LEAF)
	189	tree->leaf_head = node->next;
	190
	191	if (node->next) {
	192	tmp = hfs_bnode_find(tree, node->next);
	193	if (IS_ERR(tmp))
	194	return;
	195	tmp->prev = node->prev;
	196	cnid = cpu_to_be32(tmp->prev);
	197	hfs_bnode_write(tmp, &cnid, offsetof(struct hfs_bnode_desc, prev), 4);
	198	hfs_bnode_put(tmp);
	199	} else if (node->type == HFS_NODE_LEAF)
	200	tree->leaf_tail = node->prev;
	201
	202	// move down?
	203	if (!node->prev && !node->next) {
7cf3cc30	204	printk(KERN_DEBUG "hfs_btree_del_level\n");
1da177e4 LT	205	}
	206	if (!node->parent) {
	207	tree->root = 0;
	208	tree->depth = 0;
	209	}
	210	set_bit(HFS_BNODE_DELETED, &node->flags);
	211	}
	212
	213	static inline int hfs_bnode_hash(u32 num)
	214	{
	215	num = (num >> 16) + num;
	216	num += num >> 8;
	217	return num & (NODE_HASH_SIZE - 1);
	218	}
	219
	220	struct hfs_bnode hfs_bnode_findhash(struct hfs_btree tree, u32 cnid)
	221	{
	222	struct hfs_bnode *node;
	223
	224	if (cnid >= tree->node_count) {
d6142673	225	pr_err("request for non-existent node %d in B*Tree\n", cnid);
1da177e4 LT	226	return NULL;
	227	}
	228
	229	for (node = tree->node_hash[hfs_bnode_hash(cnid)];
	230	node; node = node->next_hash) {
	231	if (node->this == cnid) {
	232	return node;
	233	}
	234	}
	235	return NULL;
	236	}
	237
	238	static struct hfs_bnode __hfs_bnode_create(struct hfs_btree tree, u32 cnid)
	239	{
	240	struct super_block *sb;
	241	struct hfs_bnode node, node2;
	242	struct address_space *mapping;
	243	struct page *page;
	244	int size, block, i, hash;
	245	loff_t off;
	246
	247	if (cnid >= tree->node_count) {
d6142673	248	pr_err("request for non-existent node %d in B*Tree\n", cnid);
1da177e4 LT	249	return NULL;
	250	}
	251
	252	sb = tree->inode->i_sb;
	253	size = sizeof(struct hfs_bnode) + tree->pages_per_bnode *
	254	sizeof(struct page *);
f8314dc6	255	node = kzalloc(size, GFP_KERNEL);
1da177e4 LT	256	if (!node)
1da177e4 LT	257	return NULL;
1da177e4 LT	258	node->tree = tree;
	259	node->this = cnid;
	260	set_bit(HFS_BNODE_NEW, &node->flags);
	261	atomic_set(&node->refcnt, 1);
c2b3e1f7 JP	262	hfs_dbg(BNODE_REFS, "new_node(%d:%d): 1\n",
c2b3e1f7 JP	263	node->tree->cnid, node->this);
1da177e4 LT	264	init_waitqueue_head(&node->lock_wq);
	265	spin_lock(&tree->hash_lock);
	266	node2 = hfs_bnode_findhash(tree, cnid);
	267	if (!node2) {
	268	hash = hfs_bnode_hash(cnid);
	269	node->next_hash = tree->node_hash[hash];
	270	tree->node_hash[hash] = node;
	271	tree->node_hash_cnt++;
	272	} else {
	273	spin_unlock(&tree->hash_lock);
	274	kfree(node);
	275	wait_event(node2->lock_wq, !test_bit(HFS_BNODE_NEW, &node2->flags));
	276	return node2;
	277	}
	278	spin_unlock(&tree->hash_lock);
	279
	280	mapping = tree->inode->i_mapping;
	281	off = (loff_t)cnid * tree->node_size;
09cbfeaf KS	282	block = off >> PAGE_SHIFT;
09cbfeaf KS	283	node->page_offset = off & ~PAGE_MASK;
1da177e4	284	for (i = 0; i < tree->pages_per_bnode; i++) {
090d2b18	285	page = read_mapping_page(mapping, block++, NULL);
1da177e4 LT	286	if (IS_ERR(page))
	287	goto fail;
	288	if (PageError(page)) {
09cbfeaf	289	put_page(page);
1da177e4 LT	290	goto fail;
1da177e4 LT	291	}
1da177e4 LT	292	node->page[i] = page;
	293	}
	294
	295	return node;
	296	fail:
	297	set_bit(HFS_BNODE_ERROR, &node->flags);
	298	return node;
	299	}
	300
	301	void hfs_bnode_unhash(struct hfs_bnode *node)
	302	{
	303	struct hfs_bnode **p;
	304
c2b3e1f7	305	hfs_dbg(BNODE_REFS, "remove_node(%d:%d): %d\n",
1da177e4 LT	306	node->tree->cnid, node->this, atomic_read(&node->refcnt));
	307	for (p = &node->tree->node_hash[hfs_bnode_hash(node->this)];
	308	p && p != node; p = &(*p)->next_hash)
	309	;
4d4ef9ab	310	BUG_ON(!*p);
1da177e4 LT	311	*p = node->next_hash;
	312	node->tree->node_hash_cnt--;
	313	}
	314
	315	/* Load a particular node out of a tree */
	316	struct hfs_bnode hfs_bnode_find(struct hfs_btree tree, u32 num)
	317	{
	318	struct hfs_bnode *node;
	319	struct hfs_bnode_desc *desc;
	320	int i, rec_off, off, next_off;
	321	int entry_size, key_size;
	322
	323	spin_lock(&tree->hash_lock);
	324	node = hfs_bnode_findhash(tree, num);
	325	if (node) {
	326	hfs_bnode_get(node);
	327	spin_unlock(&tree->hash_lock);
	328	wait_event(node->lock_wq, !test_bit(HFS_BNODE_NEW, &node->flags));
	329	if (test_bit(HFS_BNODE_ERROR, &node->flags))
	330	goto node_error;
	331	return node;
	332	}
	333	spin_unlock(&tree->hash_lock);
	334	node = __hfs_bnode_create(tree, num);
	335	if (!node)
	336	return ERR_PTR(-ENOMEM);
	337	if (test_bit(HFS_BNODE_ERROR, &node->flags))
	338	goto node_error;
	339	if (!test_bit(HFS_BNODE_NEW, &node->flags))
	340	return node;
	341
	342	desc = (struct hfs_bnode_desc *)(kmap(node->page[0]) + node->page_offset);
	343	node->prev = be32_to_cpu(desc->prev);
	344	node->next = be32_to_cpu(desc->next);
	345	node->num_recs = be16_to_cpu(desc->num_recs);
	346	node->type = desc->type;
	347	node->height = desc->height;
	348	kunmap(node->page[0]);
	349
	350	switch (node->type) {
	351	case HFS_NODE_HEADER:
	352	case HFS_NODE_MAP:
	353	if (node->height != 0)
	354	goto node_error;
	355	break;
	356	case HFS_NODE_LEAF:
	357	if (node->height != 1)
	358	goto node_error;
	359	break;
	360	case HFS_NODE_INDEX:
	361	if (node->height <= 1 \|\| node->height > tree->depth)
	362	goto node_error;
	363	break;
	364	default:
	365	goto node_error;
	366	}
	367
	368	rec_off = tree->node_size - 2;
	369	off = hfs_bnode_read_u16(node, rec_off);
	370	if (off != sizeof(struct hfs_bnode_desc))
	371	goto node_error;
	372	for (i = 1; i <= node->num_recs; off = next_off, i++) {
	373	rec_off -= 2;
	374	next_off = hfs_bnode_read_u16(node, rec_off);
375	if (next_off <= off \|\|
376	next_off > tree->node_size \|\|
377	next_off & 1)
378	goto node_error;
379	entry_size = next_off - off;
380	if (node->type != HFS_NODE_INDEX &&
381	node->type != HFS_NODE_LEAF)
382	continue;
383	key_size = hfs_bnode_read_u8(node, off) + 1;
384	if (key_size >= entry_size /\|\| key_size & 1/)
385	goto node_error;
386	}
387	clear_bit(HFS_BNODE_NEW, &node->flags);
388	wake_up(&node->lock_wq);
389	return node;
390
391	node_error:
392	set_bit(HFS_BNODE_ERROR, &node->flags);
393	clear_bit(HFS_BNODE_NEW, &node->flags);
394	wake_up(&node->lock_wq);
395	hfs_bnode_put(node);
396	return ERR_PTR(-EIO);
397	}
398
399	void hfs_bnode_free(struct hfs_bnode *node)
400	{
7cb74be6	401	int i;
1da177e4	402
7cb74be6 HTL	403	for (i = 0; i < node->tree->pages_per_bnode; i++)
7cb74be6 HTL	404	if (node->page[i])
09cbfeaf	405	put_page(node->page[i]);
1da177e4 LT	406	kfree(node);
	407	}
	408
	409	struct hfs_bnode hfs_bnode_create(struct hfs_btree tree, u32 num)
	410	{
	411	struct hfs_bnode *node;
	412	struct page **pagep;
	413	int i;
	414
	415	spin_lock(&tree->hash_lock);
	416	node = hfs_bnode_findhash(tree, num);
	417	spin_unlock(&tree->hash_lock);
fb09c373 JM	418	if (node) {
	419	pr_crit("new node %u already hashed?\n", num);
	420	WARN_ON(1);
	421	return node;
	422	}
1da177e4 LT	423	node = __hfs_bnode_create(tree, num);
	424	if (!node)
	425	return ERR_PTR(-ENOMEM);
	426	if (test_bit(HFS_BNODE_ERROR, &node->flags)) {
	427	hfs_bnode_put(node);
	428	return ERR_PTR(-EIO);
	429	}
	430
	431	pagep = node->page;
	432	memset(kmap(*pagep) + node->page_offset, 0,
09cbfeaf	433	min((int)PAGE_SIZE, (int)tree->node_size));
1da177e4 LT	434	set_page_dirty(*pagep);
	435	kunmap(*pagep);
	436	for (i = 1; i < tree->pages_per_bnode; i++) {
09cbfeaf	437	memset(kmap(*++pagep), 0, PAGE_SIZE);
1da177e4 LT	438	set_page_dirty(*pagep);
	439	kunmap(*pagep);
	440	}
	441	clear_bit(HFS_BNODE_NEW, &node->flags);
	442	wake_up(&node->lock_wq);
	443
	444	return node;
	445	}
	446
	447	void hfs_bnode_get(struct hfs_bnode *node)
	448	{
	449	if (node) {
	450	atomic_inc(&node->refcnt);
c2b3e1f7 JP	451	hfs_dbg(BNODE_REFS, "get_node(%d:%d): %d\n",
	452	node->tree->cnid, node->this,
	453	atomic_read(&node->refcnt));
1da177e4 LT	454	}
	455	}
	456
	457	/* Dispose of resources used by a node */
	458	void hfs_bnode_put(struct hfs_bnode *node)
	459	{
	460	if (node) {
	461	struct hfs_btree *tree = node->tree;
	462	int i;
	463
c2b3e1f7 JP	464	hfs_dbg(BNODE_REFS, "put_node(%d:%d): %d\n",
	465	node->tree->cnid, node->this,
	466	atomic_read(&node->refcnt));
4d4ef9ab	467	BUG_ON(!atomic_read(&node->refcnt));
a5e3985f	468	if (!atomic_dec_and_lock(&node->refcnt, &tree->hash_lock))
1da177e4	469	return;
1da177e4	470	for (i = 0; i < tree->pages_per_bnode; i++) {
74f9c9c2 RZ	471	if (!node->page[i])
74f9c9c2 RZ	472	continue;
1da177e4	473	mark_page_accessed(node->page[i]);
1da177e4 LT	474	}
	475
	476	if (test_bit(HFS_BNODE_DELETED, &node->flags)) {
	477	hfs_bnode_unhash(node);
	478	spin_unlock(&tree->hash_lock);
	479	hfs_bmap_free(node);
	480	hfs_bnode_free(node);
	481	return;
	482	}
	483	spin_unlock(&tree->hash_lock);
	484	}
	485	}