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

// SPDX-License-Identifier: GPL-2.0
/*
 *  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/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;
	int pagenum;
	int bytes_read;
	int bytes_to_read;

	off += node->page_offset;
	pagenum = off >> PAGE_SHIFT;
	off &= ~PAGE_MASK; /* compute page offset for the first page */

	for (bytes_read = 0; bytes_read < len; bytes_read += bytes_to_read) {
		if (pagenum >= node->tree->pages_per_bnode)
			break;
		page = node->page[pagenum];
		bytes_to_read = min_t(int, len - bytes_read, PAGE_SIZE - off);

		memcpy_from_page(buf + bytes_read, page, off, bytes_to_read);

		pagenum++;
		off = 0; /* page offset only applies to the first 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_to_page(page, off, buf, len);
	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];

	memzero_page(page, off, len);
	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 page *src_page, *dst_page;

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

	memcpy_page(dst_page, dst, src_page, src, len);
	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_local_page(page);
	memmove(ptr + dst, ptr + src, len);
	kunmap_local(ptr);
	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 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;
	}

	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 {
		hfs_bnode_get(node2);
		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;
		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_local_page(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_local(desc);

	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;
	memzero_page(*pagep, node->page_offset,
		     min((int)PAGE_SIZE, (int)tree->node_size));
	set_page_dirty(*pagep);
	for (i = 1; i < tree->pages_per_bnode; i++) {
		memzero_page(*++pagep, 0, PAGE_SIZE);
		set_page_dirty(*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 ([email protected])
	7	* (C) 2003 Ardis Technologies <[email protected]>
	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
54a5ead6	18	void hfs_bnode_read(struct hfs_bnode node, void buf, int off, int len)
1da177e4 LT	19	{
1da177e4 LT	20	struct page *page;
54a5ead6 DCZX	21	int pagenum;
	22	int bytes_read;
	23	int bytes_to_read;
1da177e4 LT	24
1da177e4 LT	25	off += node->page_offset;
54a5ead6 DCZX	26	pagenum = off >> PAGE_SHIFT;
54a5ead6 DCZX	27	off &= ~PAGE_MASK; /* compute page offset for the first page */
1da177e4	28
54a5ead6 DCZX	29	for (bytes_read = 0; bytes_read < len; bytes_read += bytes_to_read) {
	30	if (pagenum >= node->tree->pages_per_bnode)
	31	break;
	32	page = node->page[pagenum];
	33	bytes_to_read = min_t(int, len - bytes_read, PAGE_SIZE - off);
	34
ca0ac8df	35	memcpy_from_page(buf + bytes_read, page, off, bytes_to_read);
54a5ead6 DCZX	36
	37	pagenum++;
	38	off = 0; /* page offset only applies to the first page */
	39	}
1da177e4 LT	40	}
	41
	42	u16 hfs_bnode_read_u16(struct hfs_bnode *node, int off)
	43	{
	44	__be16 data;
	45	// optimize later...
	46	hfs_bnode_read(node, &data, off, 2);
	47	return be16_to_cpu(data);
	48	}
	49
	50	u8 hfs_bnode_read_u8(struct hfs_bnode *node, int off)
	51	{
	52	u8 data;
	53	// optimize later...
	54	hfs_bnode_read(node, &data, off, 1);
	55	return data;
	56	}
	57
	58	void hfs_bnode_read_key(struct hfs_bnode node, void key, int off)
	59	{
	60	struct hfs_btree *tree;
	61	int key_len;
	62
	63	tree = node->tree;
	64	if (node->type == HFS_NODE_LEAF \|\|
	65	tree->attributes & HFS_TREE_VARIDXKEYS)
	66	key_len = hfs_bnode_read_u8(node, off) + 1;
	67	else
	68	key_len = tree->max_key_len + 1;
	69
	70	hfs_bnode_read(node, key, off, key_len);
	71	}
	72
	73	void hfs_bnode_write(struct hfs_bnode node, void buf, int off, int len)
	74	{
	75	struct page *page;
	76
	77	off += node->page_offset;
	78	page = node->page[0];
	79
ca0ac8df	80	memcpy_to_page(page, off, buf, len);
1da177e4 LT	81	set_page_dirty(page);
	82	}
	83
	84	void hfs_bnode_write_u16(struct hfs_bnode *node, int off, u16 data)
	85	{
	86	__be16 v = cpu_to_be16(data);
	87	// optimize later...
	88	hfs_bnode_write(node, &v, off, 2);
	89	}
	90
	91	void hfs_bnode_write_u8(struct hfs_bnode *node, int off, u8 data)
	92	{
	93	// optimize later...
	94	hfs_bnode_write(node, &data, off, 1);
	95	}
	96
	97	void hfs_bnode_clear(struct hfs_bnode *node, int off, int len)
	98	{
	99	struct page *page;
	100
	101	off += node->page_offset;
	102	page = node->page[0];
	103
ca0ac8df	104	memzero_page(page, off, len);
1da177e4 LT	105	set_page_dirty(page);
	106	}
	107
	108	void hfs_bnode_copy(struct hfs_bnode *dst_node, int dst,
	109	struct hfs_bnode *src_node, int src, int len)
	110	{
1da177e4 LT	111	struct page src_page, dst_page;
1da177e4 LT	112
c2b3e1f7	113	hfs_dbg(BNODE_MOD, "copybytes: %u,%u,%u\n", dst, src, len);
1da177e4 LT	114	if (!len)
1da177e4 LT	115	return;
1da177e4 LT	116	src += src_node->page_offset;
	117	dst += dst_node->page_offset;
	118	src_page = src_node->page[0];
	119	dst_page = dst_node->page[0];
	120
ca0ac8df	121	memcpy_page(dst_page, dst, src_page, src, len);
1da177e4 LT	122	set_page_dirty(dst_page);
	123	}
	124
	125	void hfs_bnode_move(struct hfs_bnode *node, int dst, int src, int len)
	126	{
	127	struct page *page;
	128	void *ptr;
	129
c2b3e1f7	130	hfs_dbg(BNODE_MOD, "movebytes: %u,%u,%u\n", dst, src, len);
1da177e4 LT	131	if (!len)
	132	return;
	133	src += node->page_offset;
	134	dst += node->page_offset;
	135	page = node->page[0];
ca0ac8df	136	ptr = kmap_local_page(page);
1da177e4	137	memmove(ptr + dst, ptr + src, len);
ca0ac8df	138	kunmap_local(ptr);
1da177e4 LT	139	set_page_dirty(page);
	140	}
	141
	142	void hfs_bnode_dump(struct hfs_bnode *node)
	143	{
	144	struct hfs_bnode_desc desc;
	145	__be32 cnid;
	146	int i, off, key_off;
	147
c2b3e1f7	148	hfs_dbg(BNODE_MOD, "bnode: %d\n", node->this);
1da177e4	149	hfs_bnode_read(node, &desc, 0, sizeof(desc));
c2b3e1f7	150	hfs_dbg(BNODE_MOD, "%d, %d, %d, %d, %d\n",
1da177e4 LT	151	be32_to_cpu(desc.next), be32_to_cpu(desc.prev),
	152	desc.type, desc.height, be16_to_cpu(desc.num_recs));
	153
	154	off = node->tree->node_size - 2;
	155	for (i = be16_to_cpu(desc.num_recs); i >= 0; off -= 2, i--) {
	156	key_off = hfs_bnode_read_u16(node, off);
c2b3e1f7	157	hfs_dbg_cont(BNODE_MOD, " %d", key_off);
1da177e4 LT	158	if (i && node->type == HFS_NODE_INDEX) {
	159	int tmp;
	160
	161	if (node->tree->attributes & HFS_TREE_VARIDXKEYS)
	162	tmp = (hfs_bnode_read_u8(node, key_off) \| 1) + 1;
	163	else
	164	tmp = node->tree->max_key_len + 1;
c2b3e1f7 JP	165	hfs_dbg_cont(BNODE_MOD, " (%d,%d",
c2b3e1f7 JP	166	tmp, hfs_bnode_read_u8(node, key_off));
1da177e4	167	hfs_bnode_read(node, &cnid, key_off + tmp, 4);
c2b3e1f7	168	hfs_dbg_cont(BNODE_MOD, ",%d)", be32_to_cpu(cnid));
1da177e4 LT	169	} else if (i && node->type == HFS_NODE_LEAF) {
	170	int tmp;
	171
	172	tmp = hfs_bnode_read_u8(node, key_off);
c2b3e1f7	173	hfs_dbg_cont(BNODE_MOD, " (%d)", tmp);
1da177e4 LT	174	}
1da177e4 LT	175	}
c2b3e1f7	176	hfs_dbg_cont(BNODE_MOD, "\n");
1da177e4 LT	177	}
	178
	179	void hfs_bnode_unlink(struct hfs_bnode *node)
	180	{
	181	struct hfs_btree *tree;
	182	struct hfs_bnode *tmp;
	183	__be32 cnid;
	184
	185	tree = node->tree;
	186	if (node->prev) {
	187	tmp = hfs_bnode_find(tree, node->prev);
	188	if (IS_ERR(tmp))
	189	return;
	190	tmp->next = node->next;
	191	cnid = cpu_to_be32(tmp->next);
	192	hfs_bnode_write(tmp, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
	193	hfs_bnode_put(tmp);
	194	} else if (node->type == HFS_NODE_LEAF)
	195	tree->leaf_head = node->next;
	196
	197	if (node->next) {
	198	tmp = hfs_bnode_find(tree, node->next);
	199	if (IS_ERR(tmp))
	200	return;
	201	tmp->prev = node->prev;
	202	cnid = cpu_to_be32(tmp->prev);
	203	hfs_bnode_write(tmp, &cnid, offsetof(struct hfs_bnode_desc, prev), 4);
	204	hfs_bnode_put(tmp);
	205	} else if (node->type == HFS_NODE_LEAF)
	206	tree->leaf_tail = node->prev;
	207
	208	// move down?
	209	if (!node->prev && !node->next) {
7cf3cc30	210	printk(KERN_DEBUG "hfs_btree_del_level\n");
1da177e4 LT	211	}
	212	if (!node->parent) {
	213	tree->root = 0;
	214	tree->depth = 0;
	215	}
	216	set_bit(HFS_BNODE_DELETED, &node->flags);
	217	}
	218
	219	static inline int hfs_bnode_hash(u32 num)
	220	{
	221	num = (num >> 16) + num;
	222	num += num >> 8;
	223	return num & (NODE_HASH_SIZE - 1);
	224	}
	225
	226	struct hfs_bnode hfs_bnode_findhash(struct hfs_btree tree, u32 cnid)
	227	{
	228	struct hfs_bnode *node;
	229
	230	if (cnid >= tree->node_count) {
d6142673	231	pr_err("request for non-existent node %d in B*Tree\n", cnid);
1da177e4 LT	232	return NULL;
	233	}
	234
	235	for (node = tree->node_hash[hfs_bnode_hash(cnid)];
	236	node; node = node->next_hash) {
	237	if (node->this == cnid) {
	238	return node;
	239	}
	240	}
	241	return NULL;
	242	}
	243
	244	static struct hfs_bnode __hfs_bnode_create(struct hfs_btree tree, u32 cnid)
	245	{
1da177e4 LT	246	struct hfs_bnode node, node2;
	247	struct address_space *mapping;
	248	struct page *page;
	249	int size, block, i, hash;
	250	loff_t off;
	251
	252	if (cnid >= tree->node_count) {
d6142673	253	pr_err("request for non-existent node %d in B*Tree\n", cnid);
1da177e4 LT	254	return NULL;
	255	}
	256
1da177e4 LT	257	size = sizeof(struct hfs_bnode) + tree->pages_per_bnode *
1da177e4 LT	258	sizeof(struct page *);
f8314dc6	259	node = kzalloc(size, GFP_KERNEL);
1da177e4 LT	260	if (!node)
1da177e4 LT	261	return NULL;
1da177e4 LT	262	node->tree = tree;
	263	node->this = cnid;
	264	set_bit(HFS_BNODE_NEW, &node->flags);
	265	atomic_set(&node->refcnt, 1);
c2b3e1f7 JP	266	hfs_dbg(BNODE_REFS, "new_node(%d:%d): 1\n",
c2b3e1f7 JP	267	node->tree->cnid, node->this);
1da177e4 LT	268	init_waitqueue_head(&node->lock_wq);
	269	spin_lock(&tree->hash_lock);
	270	node2 = hfs_bnode_findhash(tree, cnid);
	271	if (!node2) {
	272	hash = hfs_bnode_hash(cnid);
	273	node->next_hash = tree->node_hash[hash];
	274	tree->node_hash[hash] = node;
	275	tree->node_hash_cnt++;
	276	} else {
a9dc087f	277	hfs_bnode_get(node2);
1da177e4 LT	278	spin_unlock(&tree->hash_lock);
	279	kfree(node);
	280	wait_event(node2->lock_wq, !test_bit(HFS_BNODE_NEW, &node2->flags));
	281	return node2;
	282	}
	283	spin_unlock(&tree->hash_lock);
	284
	285	mapping = tree->inode->i_mapping;
	286	off = (loff_t)cnid * tree->node_size;
09cbfeaf KS	287	block = off >> PAGE_SHIFT;
09cbfeaf KS	288	node->page_offset = off & ~PAGE_MASK;
1da177e4	289	for (i = 0; i < tree->pages_per_bnode; i++) {
090d2b18	290	page = read_mapping_page(mapping, block++, NULL);
1da177e4 LT	291	if (IS_ERR(page))
1da177e4 LT	292	goto fail;
1da177e4 LT	293	node->page[i] = page;
	294	}
	295
	296	return node;
	297	fail:
	298	set_bit(HFS_BNODE_ERROR, &node->flags);
	299	return node;
	300	}
	301
	302	void hfs_bnode_unhash(struct hfs_bnode *node)
	303	{
	304	struct hfs_bnode **p;
	305
c2b3e1f7	306	hfs_dbg(BNODE_REFS, "remove_node(%d:%d): %d\n",
1da177e4 LT	307	node->tree->cnid, node->this, atomic_read(&node->refcnt));
	308	for (p = &node->tree->node_hash[hfs_bnode_hash(node->this)];
	309	p && p != node; p = &(*p)->next_hash)
	310	;
4d4ef9ab	311	BUG_ON(!*p);
1da177e4 LT	312	*p = node->next_hash;
	313	node->tree->node_hash_cnt--;
	314	}
	315
	316	/* Load a particular node out of a tree */
	317	struct hfs_bnode hfs_bnode_find(struct hfs_btree tree, u32 num)
	318	{
	319	struct hfs_bnode *node;
	320	struct hfs_bnode_desc *desc;
	321	int i, rec_off, off, next_off;
	322	int entry_size, key_size;
	323
	324	spin_lock(&tree->hash_lock);
	325	node = hfs_bnode_findhash(tree, num);
	326	if (node) {
	327	hfs_bnode_get(node);
	328	spin_unlock(&tree->hash_lock);
	329	wait_event(node->lock_wq, !test_bit(HFS_BNODE_NEW, &node->flags));
	330	if (test_bit(HFS_BNODE_ERROR, &node->flags))
	331	goto node_error;
	332	return node;
	333	}
	334	spin_unlock(&tree->hash_lock);
	335	node = __hfs_bnode_create(tree, num);
	336	if (!node)
	337	return ERR_PTR(-ENOMEM);
	338	if (test_bit(HFS_BNODE_ERROR, &node->flags))
	339	goto node_error;
	340	if (!test_bit(HFS_BNODE_NEW, &node->flags))
	341	return node;
	342
ca0ac8df FDF	343	desc = (struct hfs_bnode_desc *)(kmap_local_page(node->page[0]) +
ca0ac8df FDF	344	node->page_offset);
1da177e4 LT	345	node->prev = be32_to_cpu(desc->prev);
	346	node->next = be32_to_cpu(desc->next);
	347	node->num_recs = be16_to_cpu(desc->num_recs);
	348	node->type = desc->type;
	349	node->height = desc->height;
ca0ac8df	350	kunmap_local(desc);
1da177e4 LT	351
	352	switch (node->type) {
	353	case HFS_NODE_HEADER:
	354	case HFS_NODE_MAP:
	355	if (node->height != 0)
	356	goto node_error;
	357	break;
	358	case HFS_NODE_LEAF:
	359	if (node->height != 1)
	360	goto node_error;
	361	break;
	362	case HFS_NODE_INDEX:
	363	if (node->height <= 1 \|\| node->height > tree->depth)
	364	goto node_error;
	365	break;
	366	default:
	367	goto node_error;
	368	}
	369
	370	rec_off = tree->node_size - 2;
	371	off = hfs_bnode_read_u16(node, rec_off);
	372	if (off != sizeof(struct hfs_bnode_desc))
	373	goto node_error;
	374	for (i = 1; i <= node->num_recs; off = next_off, i++) {
	375	rec_off -= 2;
	376	next_off = hfs_bnode_read_u16(node, rec_off);
	377	if (next_off <= off \|\|
	378	next_off > tree->node_size \|\|
	379	next_off & 1)
	380	goto node_error;
	381	entry_size = next_off - off;
	382	if (node->type != HFS_NODE_INDEX &&
	383	node->type != HFS_NODE_LEAF)
	384	continue;
	385	key_size = hfs_bnode_read_u8(node, off) + 1;
	386	if (key_size >= entry_size /\|\| key_size & 1/)
	387	goto node_error;
	388	}
	389	clear_bit(HFS_BNODE_NEW, &node->flags);
	390	wake_up(&node->lock_wq);
	391	return node;
	392
	393	node_error:
	394	set_bit(HFS_BNODE_ERROR, &node->flags);
	395	clear_bit(HFS_BNODE_NEW, &node->flags);
	396	wake_up(&node->lock_wq);
	397	hfs_bnode_put(node);
	398	return ERR_PTR(-EIO);
	399	}
	400
	401	void hfs_bnode_free(struct hfs_bnode *node)
	402	{
7cb74be6	403	int i;
1da177e4	404
7cb74be6 HTL	405	for (i = 0; i < node->tree->pages_per_bnode; i++)
7cb74be6 HTL	406	if (node->page[i])
09cbfeaf	407	put_page(node->page[i]);
1da177e4 LT	408	kfree(node);
	409	}
	410
	411	struct hfs_bnode hfs_bnode_create(struct hfs_btree tree, u32 num)
	412	{
	413	struct hfs_bnode *node;
	414	struct page **pagep;
	415	int i;
	416
	417	spin_lock(&tree->hash_lock);
	418	node = hfs_bnode_findhash(tree, num);
	419	spin_unlock(&tree->hash_lock);
fb09c373 JM	420	if (node) {
	421	pr_crit("new node %u already hashed?\n", num);
	422	WARN_ON(1);
	423	return node;
	424	}
1da177e4 LT	425	node = __hfs_bnode_create(tree, num);
	426	if (!node)
	427	return ERR_PTR(-ENOMEM);
	428	if (test_bit(HFS_BNODE_ERROR, &node->flags)) {
	429	hfs_bnode_put(node);
	430	return ERR_PTR(-EIO);
	431	}
	432
	433	pagep = node->page;
ca0ac8df FDF	434	memzero_page(*pagep, node->page_offset,
ca0ac8df FDF	435	min((int)PAGE_SIZE, (int)tree->node_size));
1da177e4	436	set_page_dirty(*pagep);
1da177e4	437	for (i = 1; i < tree->pages_per_bnode; i++) {
ca0ac8df	438	memzero_page(*++pagep, 0, PAGE_SIZE);
1da177e4	439	set_page_dirty(*pagep);
1da177e4 LT	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	}