[linux.git] / fs / hfs / bnode.c

/*
 *  linux/fs/hfs/bnode.c
 *
 * Copyright (C) 2001
 * Brad Boyer ([email protected])
 * (C) 2003 Ardis Technologies <[email protected]>
 *
 * Handle basic btree node operations
 */

#include <linux/pagemap.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;

	dprint(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;

	dprint(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;

	dprint(DBG_BNODE_MOD, "bnode: %d\n", node->this);
	hfs_bnode_read(node, &desc, 0, sizeof(desc));
	dprint(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);
		dprint(DBG_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;
			dprint(DBG_BNODE_MOD, " (%d,%d", tmp, hfs_bnode_read_u8(node, key_off));
			hfs_bnode_read(node, &cnid, key_off + tmp, 4);
			dprint(DBG_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);
			dprint(DBG_BNODE_MOD, " (%d)", tmp);
		}
	}
	dprint(DBG_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) {
		printk(KERN_ERR "hfs: 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) {
		printk(KERN_ERR "hfs: 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 = kmalloc(size, GFP_KERNEL);
	if (!node)
		return NULL;
	memset(node, 0, size);
	node->tree = tree;
	node->this = cnid;
	set_bit(HFS_BNODE_NEW, &node->flags);
	atomic_set(&node->refcnt, 1);
	dprint(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_CACHE_SHIFT;
	node->page_offset = off & ~PAGE_CACHE_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)) {
			page_cache_release(page);
			goto fail;
		}
		page_cache_release(page);
		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;

	dprint(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])
	//		page_cache_release(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);
	BUG_ON(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_CACHE_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_CACHE_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);
		dprint(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;

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