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

// SPDX-License-Identifier: GPL-2.0
/*
 *  linux/fs/hfs/btree.c
 *
 * Copyright (C) 2001
 * Brad Boyer ([email protected])
 * (C) 2003 Ardis Technologies <[email protected]>
 *
 * Handle opening/closing btree
 */

#include <linux/pagemap.h>
#include <linux/slab.h>
#include <linux/log2.h>

#include "btree.h"

/* Get a reference to a B*Tree and do some initial checks */
struct hfs_btree *hfs_btree_open(struct super_block *sb, u32 id, btree_keycmp keycmp)
{
	struct hfs_btree *tree;
	struct hfs_btree_header_rec *head;
	struct address_space *mapping;
	struct page *page;
	unsigned int size;

	tree = kzalloc(sizeof(*tree), GFP_KERNEL);
	if (!tree)
		return NULL;

	mutex_init(&tree->tree_lock);
	spin_lock_init(&tree->hash_lock);
	/* Set the correct compare function */
	tree->sb = sb;
	tree->cnid = id;
	tree->keycmp = keycmp;

	tree->inode = iget_locked(sb, id);
	if (!tree->inode)
		goto free_tree;
	BUG_ON(!(tree->inode->i_state & I_NEW));
	{
	struct hfs_mdb *mdb = HFS_SB(sb)->mdb;
	HFS_I(tree->inode)->flags = 0;
	mutex_init(&HFS_I(tree->inode)->extents_lock);
	switch (id) {
	case HFS_EXT_CNID:
		hfs_inode_read_fork(tree->inode, mdb->drXTExtRec, mdb->drXTFlSize,
				    mdb->drXTFlSize, be32_to_cpu(mdb->drXTClpSiz));
		if (HFS_I(tree->inode)->alloc_blocks >
					HFS_I(tree->inode)->first_blocks) {
			pr_err("invalid btree extent records\n");
			unlock_new_inode(tree->inode);
			goto free_inode;
		}

		tree->inode->i_mapping->a_ops = &hfs_btree_aops;
		break;
	case HFS_CAT_CNID:
		hfs_inode_read_fork(tree->inode, mdb->drCTExtRec, mdb->drCTFlSize,
				    mdb->drCTFlSize, be32_to_cpu(mdb->drCTClpSiz));

		if (!HFS_I(tree->inode)->first_blocks) {
			pr_err("invalid btree extent records (0 size)\n");
			unlock_new_inode(tree->inode);
			goto free_inode;
		}

		tree->inode->i_mapping->a_ops = &hfs_btree_aops;
		break;
	default:
		BUG();
	}
	}
	unlock_new_inode(tree->inode);

	mapping = tree->inode->i_mapping;
	page = read_mapping_page(mapping, 0, NULL);
	if (IS_ERR(page))
		goto free_inode;

	/* Load the header */
	head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc));
	tree->root = be32_to_cpu(head->root);
	tree->leaf_count = be32_to_cpu(head->leaf_count);
	tree->leaf_head = be32_to_cpu(head->leaf_head);
	tree->leaf_tail = be32_to_cpu(head->leaf_tail);
	tree->node_count = be32_to_cpu(head->node_count);
	tree->free_nodes = be32_to_cpu(head->free_nodes);
	tree->attributes = be32_to_cpu(head->attributes);
	tree->node_size = be16_to_cpu(head->node_size);
	tree->max_key_len = be16_to_cpu(head->max_key_len);
	tree->depth = be16_to_cpu(head->depth);

	size = tree->node_size;
	if (!is_power_of_2(size))
		goto fail_page;
	if (!tree->node_count)
		goto fail_page;
	switch (id) {
	case HFS_EXT_CNID:
		if (tree->max_key_len != HFS_MAX_EXT_KEYLEN) {
			pr_err("invalid extent max_key_len %d\n",
			       tree->max_key_len);
			goto fail_page;
		}
		break;
	case HFS_CAT_CNID:
		if (tree->max_key_len != HFS_MAX_CAT_KEYLEN) {
			pr_err("invalid catalog max_key_len %d\n",
			       tree->max_key_len);
			goto fail_page;
		}
		break;
	default:
		BUG();
	}

	tree->node_size_shift = ffs(size) - 1;
	tree->pages_per_bnode = (tree->node_size + PAGE_SIZE - 1) >> PAGE_SHIFT;

	kunmap(page);
	put_page(page);
	return tree;

fail_page:
	put_page(page);
free_inode:
	tree->inode->i_mapping->a_ops = &hfs_aops;
	iput(tree->inode);
free_tree:
	kfree(tree);
	return NULL;
}

/* Release resources used by a btree */
void hfs_btree_close(struct hfs_btree *tree)
{
	struct hfs_bnode *node;
	int i;

	if (!tree)
		return;

	for (i = 0; i < NODE_HASH_SIZE; i++) {
		while ((node = tree->node_hash[i])) {
			tree->node_hash[i] = node->next_hash;
			if (atomic_read(&node->refcnt))
				pr_err("node %d:%d still has %d user(s)!\n",
				       node->tree->cnid, node->this,
				       atomic_read(&node->refcnt));
			hfs_bnode_free(node);
			tree->node_hash_cnt--;
		}
	}
	iput(tree->inode);
	kfree(tree);
}

void hfs_btree_write(struct hfs_btree *tree)
{
	struct hfs_btree_header_rec *head;
	struct hfs_bnode *node;
	struct page *page;

	node = hfs_bnode_find(tree, 0);
	if (IS_ERR(node))
		/* panic? */
		return;
	/* Load the header */
	page = node->page[0];
	head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc));

	head->root = cpu_to_be32(tree->root);
	head->leaf_count = cpu_to_be32(tree->leaf_count);
	head->leaf_head = cpu_to_be32(tree->leaf_head);
	head->leaf_tail = cpu_to_be32(tree->leaf_tail);
	head->node_count = cpu_to_be32(tree->node_count);
	head->free_nodes = cpu_to_be32(tree->free_nodes);
	head->attributes = cpu_to_be32(tree->attributes);
	head->depth = cpu_to_be16(tree->depth);

	kunmap(page);
	set_page_dirty(page);
	hfs_bnode_put(node);
}

static struct hfs_bnode *hfs_bmap_new_bmap(struct hfs_bnode *prev, u32 idx)
{
	struct hfs_btree *tree = prev->tree;
	struct hfs_bnode *node;
	struct hfs_bnode_desc desc;
	__be32 cnid;

	node = hfs_bnode_create(tree, idx);
	if (IS_ERR(node))
		return node;

	if (!tree->free_nodes)
		panic("FIXME!!!");
	tree->free_nodes--;
	prev->next = idx;
	cnid = cpu_to_be32(idx);
	hfs_bnode_write(prev, &cnid, offsetof(struct hfs_bnode_desc, next), 4);

	node->type = HFS_NODE_MAP;
	node->num_recs = 1;
	hfs_bnode_clear(node, 0, tree->node_size);
	desc.next = 0;
	desc.prev = 0;
	desc.type = HFS_NODE_MAP;
	desc.height = 0;
	desc.num_recs = cpu_to_be16(1);
	desc.reserved = 0;
	hfs_bnode_write(node, &desc, 0, sizeof(desc));
	hfs_bnode_write_u16(node, 14, 0x8000);
	hfs_bnode_write_u16(node, tree->node_size - 2, 14);
	hfs_bnode_write_u16(node, tree->node_size - 4, tree->node_size - 6);

	return node;
}

struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree)
{
	struct hfs_bnode *node, *next_node;
	struct page **pagep;
	u32 nidx, idx;
	unsigned off;
	u16 off16;
	u16 len;
	u8 *data, byte, m;
	int i;

	while (!tree->free_nodes) {
		struct inode *inode = tree->inode;
		u32 count;
		int res;

		res = hfs_extend_file(inode);
		if (res)
			return ERR_PTR(res);
		HFS_I(inode)->phys_size = inode->i_size =
				(loff_t)HFS_I(inode)->alloc_blocks *
				HFS_SB(tree->sb)->alloc_blksz;
		HFS_I(inode)->fs_blocks = inode->i_size >>
					  tree->sb->s_blocksize_bits;
		inode_set_bytes(inode, inode->i_size);
		count = inode->i_size >> tree->node_size_shift;
		tree->free_nodes = count - tree->node_count;
		tree->node_count = count;
	}

	nidx = 0;
	node = hfs_bnode_find(tree, nidx);
	if (IS_ERR(node))
		return node;
	len = hfs_brec_lenoff(node, 2, &off16);
	off = off16;

	off += node->page_offset;
	pagep = node->page + (off >> PAGE_SHIFT);
	data = kmap(*pagep);
	off &= ~PAGE_MASK;
	idx = 0;

	for (;;) {
		while (len) {
			byte = data[off];
			if (byte != 0xff) {
				for (m = 0x80, i = 0; i < 8; m >>= 1, i++) {
					if (!(byte & m)) {
						idx += i;
						data[off] |= m;
						set_page_dirty(*pagep);
						kunmap(*pagep);
						tree->free_nodes--;
						mark_inode_dirty(tree->inode);
						hfs_bnode_put(node);
						return hfs_bnode_create(tree, idx);
					}
				}
			}
			if (++off >= PAGE_SIZE) {
				kunmap(*pagep);
				data = kmap(*++pagep);
				off = 0;
			}
			idx += 8;
			len--;
		}
		kunmap(*pagep);
		nidx = node->next;
		if (!nidx) {
			printk(KERN_DEBUG "create new bmap node...\n");
			next_node = hfs_bmap_new_bmap(node, idx);
		} else
			next_node = hfs_bnode_find(tree, nidx);
		hfs_bnode_put(node);
		if (IS_ERR(next_node))
			return next_node;
		node = next_node;

		len = hfs_brec_lenoff(node, 0, &off16);
		off = off16;
		off += node->page_offset;
		pagep = node->page + (off >> PAGE_SHIFT);
		data = kmap(*pagep);
		off &= ~PAGE_MASK;
	}
}

void hfs_bmap_free(struct hfs_bnode *node)
{
	struct hfs_btree *tree;
	struct page *page;
	u16 off, len;
	u32 nidx;
	u8 *data, byte, m;

	hfs_dbg(BNODE_MOD, "btree_free_node: %u\n", node->this);
	tree = node->tree;
	nidx = node->this;
	node = hfs_bnode_find(tree, 0);
	if (IS_ERR(node))
		return;
	len = hfs_brec_lenoff(node, 2, &off);
	while (nidx >= len * 8) {
		u32 i;

		nidx -= len * 8;
		i = node->next;
		hfs_bnode_put(node);
		if (!i) {
			/* panic */;
			pr_crit("unable to free bnode %u. bmap not found!\n",
				node->this);
			return;
		}
		node = hfs_bnode_find(tree, i);
		if (IS_ERR(node))
			return;
		if (node->type != HFS_NODE_MAP) {
			/* panic */;
			pr_crit("invalid bmap found! (%u,%d)\n",
				node->this, node->type);
			hfs_bnode_put(node);
			return;
		}
		len = hfs_brec_lenoff(node, 0, &off);
	}
	off += node->page_offset + nidx / 8;
	page = node->page[off >> PAGE_SHIFT];
	data = kmap(page);
	off &= ~PAGE_MASK;
	m = 1 << (~nidx & 7);
	byte = data[off];
	if (!(byte & m)) {
		pr_crit("trying to free free bnode %u(%d)\n",
			node->this, node->type);
		kunmap(page);
		hfs_bnode_put(node);
		return;
	}
	data[off] = byte & ~m;
	set_page_dirty(page);
	kunmap(page);
	hfs_bnode_put(node);
	tree->free_nodes++;
	mark_inode_dirty(tree->inode);
}
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
1da177e4 LT	2	/*
	3	* linux/fs/hfs/btree.c
	4	*
	5	* Copyright (C) 2001
	6	* Brad Boyer ([email protected])
	7	* (C) 2003 Ardis Technologies <[email protected]>
	8	*
	9	* Handle opening/closing btree
	10	*/
	11
	12	#include <linux/pagemap.h>
5a0e3ad6	13	#include <linux/slab.h>
e1b5c1d3	14	#include <linux/log2.h>
1da177e4 LT	15
	16	#include "btree.h"
	17
	18	/* Get a reference to a BTree and do some initial checks /
	19	struct hfs_btree hfs_btree_open(struct super_block sb, u32 id, btree_keycmp keycmp)
	20	{
	21	struct hfs_btree *tree;
	22	struct hfs_btree_header_rec *head;
	23	struct address_space *mapping;
	24	struct page *page;
	25	unsigned int size;
	26
f8314dc6	27	tree = kzalloc(sizeof(*tree), GFP_KERNEL);
1da177e4 LT	28	if (!tree)
1da177e4 LT	29	return NULL;
1da177e4	30
4a941035	31	mutex_init(&tree->tree_lock);
1da177e4 LT	32	spin_lock_init(&tree->hash_lock);
	33	/* Set the correct compare function */
	34	tree->sb = sb;
	35	tree->cnid = id;
	36	tree->keycmp = keycmp;
	37
	38	tree->inode = iget_locked(sb, id);
	39	if (!tree->inode)
	40	goto free_tree;
4d4ef9ab	41	BUG_ON(!(tree->inode->i_state & I_NEW));
1da177e4 LT	42	{
	43	struct hfs_mdb *mdb = HFS_SB(sb)->mdb;
	44	HFS_I(tree->inode)->flags = 0;
39f8d472	45	mutex_init(&HFS_I(tree->inode)->extents_lock);
1da177e4 LT	46	switch (id) {
	47	case HFS_EXT_CNID:
	48	hfs_inode_read_fork(tree->inode, mdb->drXTExtRec, mdb->drXTFlSize,
	49	mdb->drXTFlSize, be32_to_cpu(mdb->drXTClpSiz));
434a964d PL	50	if (HFS_I(tree->inode)->alloc_blocks >
434a964d PL	51	HFS_I(tree->inode)->first_blocks) {
d6142673	52	pr_err("invalid btree extent records\n");
434a964d PL	53	unlock_new_inode(tree->inode);
	54	goto free_inode;
	55	}
	56
1da177e4 LT	57	tree->inode->i_mapping->a_ops = &hfs_btree_aops;
	58	break;
	59	case HFS_CAT_CNID:
	60	hfs_inode_read_fork(tree->inode, mdb->drCTExtRec, mdb->drCTFlSize,
	61	mdb->drCTFlSize, be32_to_cpu(mdb->drCTClpSiz));
434a964d PL	62
434a964d PL	63	if (!HFS_I(tree->inode)->first_blocks) {
d6142673	64	pr_err("invalid btree extent records (0 size)\n");
434a964d PL	65	unlock_new_inode(tree->inode);
	66	goto free_inode;
	67	}
	68
1da177e4 LT	69	tree->inode->i_mapping->a_ops = &hfs_btree_aops;
	70	break;
	71	default:
	72	BUG();
	73	}
	74	}
	75	unlock_new_inode(tree->inode);
	76
	77	mapping = tree->inode->i_mapping;
090d2b18	78	page = read_mapping_page(mapping, 0, NULL);
1da177e4	79	if (IS_ERR(page))
46a39c1c	80	goto free_inode;
1da177e4 LT	81
	82	/* Load the header */
	83	head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc));
	84	tree->root = be32_to_cpu(head->root);
	85	tree->leaf_count = be32_to_cpu(head->leaf_count);
	86	tree->leaf_head = be32_to_cpu(head->leaf_head);
	87	tree->leaf_tail = be32_to_cpu(head->leaf_tail);
	88	tree->node_count = be32_to_cpu(head->node_count);
	89	tree->free_nodes = be32_to_cpu(head->free_nodes);
	90	tree->attributes = be32_to_cpu(head->attributes);
	91	tree->node_size = be16_to_cpu(head->node_size);
	92	tree->max_key_len = be16_to_cpu(head->max_key_len);
	93	tree->depth = be16_to_cpu(head->depth);
	94
	95	size = tree->node_size;
e1b5c1d3	96	if (!is_power_of_2(size))
1da177e4 LT	97	goto fail_page;
	98	if (!tree->node_count)
	99	goto fail_page;
55581d01 ES	100	switch (id) {
	101	case HFS_EXT_CNID:
	102	if (tree->max_key_len != HFS_MAX_EXT_KEYLEN) {
d6142673 JP	103	pr_err("invalid extent max_key_len %d\n",
d6142673 JP	104	tree->max_key_len);
55581d01 ES	105	goto fail_page;
	106	}
	107	break;
	108	case HFS_CAT_CNID:
	109	if (tree->max_key_len != HFS_MAX_CAT_KEYLEN) {
d6142673 JP	110	pr_err("invalid catalog max_key_len %d\n",
d6142673 JP	111	tree->max_key_len);
55581d01 ES	112	goto fail_page;
	113	}
	114	break;
	115	default:
	116	BUG();
cf059462 ES	117	}
cf059462 ES	118
1da177e4	119	tree->node_size_shift = ffs(size) - 1;
09cbfeaf	120	tree->pages_per_bnode = (tree->node_size + PAGE_SIZE - 1) >> PAGE_SHIFT;
1da177e4 LT	121
1da177e4 LT	122	kunmap(page);
09cbfeaf	123	put_page(page);
1da177e4 LT	124	return tree;
1da177e4 LT	125
46a39c1c	126	fail_page:
09cbfeaf	127	put_page(page);
46a39c1c	128	free_inode:
cf059462	129	tree->inode->i_mapping->a_ops = &hfs_aops;
1da177e4	130	iput(tree->inode);
46a39c1c	131	free_tree:
1da177e4 LT	132	kfree(tree);
	133	return NULL;
	134	}
	135
	136	/* Release resources used by a btree */
	137	void hfs_btree_close(struct hfs_btree *tree)
	138	{
	139	struct hfs_bnode *node;
	140	int i;
	141
	142	if (!tree)
	143	return;
	144
	145	for (i = 0; i < NODE_HASH_SIZE; i++) {
	146	while ((node = tree->node_hash[i])) {
	147	tree->node_hash[i] = node->next_hash;
	148	if (atomic_read(&node->refcnt))
d6142673 JP	149	pr_err("node %d:%d still has %d user(s)!\n",
	150	node->tree->cnid, node->this,
	151	atomic_read(&node->refcnt));
1da177e4 LT	152	hfs_bnode_free(node);
	153	tree->node_hash_cnt--;
	154	}
	155	}
	156	iput(tree->inode);
	157	kfree(tree);
	158	}
	159
	160	void hfs_btree_write(struct hfs_btree *tree)
	161	{
	162	struct hfs_btree_header_rec *head;
	163	struct hfs_bnode *node;
	164	struct page *page;
	165
	166	node = hfs_bnode_find(tree, 0);
	167	if (IS_ERR(node))
	168	/* panic? */
	169	return;
	170	/* Load the header */
	171	page = node->page[0];
	172	head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc));
	173
	174	head->root = cpu_to_be32(tree->root);
	175	head->leaf_count = cpu_to_be32(tree->leaf_count);
	176	head->leaf_head = cpu_to_be32(tree->leaf_head);
	177	head->leaf_tail = cpu_to_be32(tree->leaf_tail);
	178	head->node_count = cpu_to_be32(tree->node_count);
	179	head->free_nodes = cpu_to_be32(tree->free_nodes);
	180	head->attributes = cpu_to_be32(tree->attributes);
	181	head->depth = cpu_to_be16(tree->depth);
	182
	183	kunmap(page);
	184	set_page_dirty(page);
	185	hfs_bnode_put(node);
	186	}
	187
	188	static struct hfs_bnode hfs_bmap_new_bmap(struct hfs_bnode prev, u32 idx)
	189	{
	190	struct hfs_btree *tree = prev->tree;
	191	struct hfs_bnode *node;
	192	struct hfs_bnode_desc desc;
	193	__be32 cnid;
	194
	195	node = hfs_bnode_create(tree, idx);
	196	if (IS_ERR(node))
	197	return node;
	198
	199	if (!tree->free_nodes)
	200	panic("FIXME!!!");
	201	tree->free_nodes--;
	202	prev->next = idx;
	203	cnid = cpu_to_be32(idx);
	204	hfs_bnode_write(prev, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
	205
	206	node->type = HFS_NODE_MAP;
	207	node->num_recs = 1;
	208	hfs_bnode_clear(node, 0, tree->node_size);
	209	desc.next = 0;
	210	desc.prev = 0;
	211	desc.type = HFS_NODE_MAP;
	212	desc.height = 0;
	213	desc.num_recs = cpu_to_be16(1);
	214	desc.reserved = 0;
	215	hfs_bnode_write(node, &desc, 0, sizeof(desc));
216	hfs_bnode_write_u16(node, 14, 0x8000);
217	hfs_bnode_write_u16(node, tree->node_size - 2, 14);
218	hfs_bnode_write_u16(node, tree->node_size - 4, tree->node_size - 6);
219
220	return node;
221	}
222
223	struct hfs_bnode hfs_bmap_alloc(struct hfs_btree tree)
224	{
225	struct hfs_bnode node, next_node;
226	struct page **pagep;
227	u32 nidx, idx;
3e5a5097 AM	228	unsigned off;
	229	u16 off16;
	230	u16 len;
1da177e4 LT	231	u8 *data, byte, m;
	232	int i;
	233
	234	while (!tree->free_nodes) {
	235	struct inode *inode = tree->inode;
	236	u32 count;
	237	int res;
	238
	239	res = hfs_extend_file(inode);
	240	if (res)
	241	return ERR_PTR(res);
	242	HFS_I(inode)->phys_size = inode->i_size =
	243	(loff_t)HFS_I(inode)->alloc_blocks *
	244	HFS_SB(tree->sb)->alloc_blksz;
	245	HFS_I(inode)->fs_blocks = inode->i_size >>
	246	tree->sb->s_blocksize_bits;
	247	inode_set_bytes(inode, inode->i_size);
	248	count = inode->i_size >> tree->node_size_shift;
	249	tree->free_nodes = count - tree->node_count;
	250	tree->node_count = count;
	251	}
	252
	253	nidx = 0;
	254	node = hfs_bnode_find(tree, nidx);
	255	if (IS_ERR(node))
	256	return node;
3e5a5097 AM	257	len = hfs_brec_lenoff(node, 2, &off16);
3e5a5097 AM	258	off = off16;
1da177e4 LT	259
1da177e4 LT	260	off += node->page_offset;
09cbfeaf	261	pagep = node->page + (off >> PAGE_SHIFT);
1da177e4	262	data = kmap(*pagep);
09cbfeaf	263	off &= ~PAGE_MASK;
1da177e4 LT	264	idx = 0;
	265
	266	for (;;) {
	267	while (len) {
	268	byte = data[off];
	269	if (byte != 0xff) {
	270	for (m = 0x80, i = 0; i < 8; m >>= 1, i++) {
	271	if (!(byte & m)) {
	272	idx += i;
	273	data[off] \|= m;
	274	set_page_dirty(*pagep);
	275	kunmap(*pagep);
	276	tree->free_nodes--;
	277	mark_inode_dirty(tree->inode);
	278	hfs_bnode_put(node);
	279	return hfs_bnode_create(tree, idx);
	280	}
	281	}
	282	}
09cbfeaf	283	if (++off >= PAGE_SIZE) {
1da177e4 LT	284	kunmap(*pagep);
	285	data = kmap(*++pagep);
	286	off = 0;
	287	}
	288	idx += 8;
	289	len--;
	290	}
	291	kunmap(*pagep);
	292	nidx = node->next;
	293	if (!nidx) {
d6142673	294	printk(KERN_DEBUG "create new bmap node...\n");
1da177e4 LT	295	next_node = hfs_bmap_new_bmap(node, idx);
	296	} else
	297	next_node = hfs_bnode_find(tree, nidx);
	298	hfs_bnode_put(node);
	299	if (IS_ERR(next_node))
	300	return next_node;
	301	node = next_node;
	302
3e5a5097 AM	303	len = hfs_brec_lenoff(node, 0, &off16);
3e5a5097 AM	304	off = off16;
1da177e4	305	off += node->page_offset;
09cbfeaf	306	pagep = node->page + (off >> PAGE_SHIFT);
1da177e4	307	data = kmap(*pagep);
09cbfeaf	308	off &= ~PAGE_MASK;
1da177e4 LT	309	}
	310	}
	311
	312	void hfs_bmap_free(struct hfs_bnode *node)
	313	{
	314	struct hfs_btree *tree;
	315	struct page *page;
	316	u16 off, len;
	317	u32 nidx;
	318	u8 *data, byte, m;
	319
c2b3e1f7	320	hfs_dbg(BNODE_MOD, "btree_free_node: %u\n", node->this);
1da177e4 LT	321	tree = node->tree;
	322	nidx = node->this;
	323	node = hfs_bnode_find(tree, 0);
	324	if (IS_ERR(node))
	325	return;
	326	len = hfs_brec_lenoff(node, 2, &off);
	327	while (nidx >= len * 8) {
	328	u32 i;
	329
	330	nidx -= len * 8;
	331	i = node->next;
	332	hfs_bnode_put(node);
	333	if (!i) {
	334	/* panic */;
d6142673 JP	335	pr_crit("unable to free bnode %u. bmap not found!\n",
d6142673 JP	336	node->this);
1da177e4 LT	337	return;
	338	}
	339	node = hfs_bnode_find(tree, i);
	340	if (IS_ERR(node))
	341	return;
	342	if (node->type != HFS_NODE_MAP) {
	343	/* panic */;
d6142673 JP	344	pr_crit("invalid bmap found! (%u,%d)\n",
d6142673 JP	345	node->this, node->type);
1da177e4 LT	346	hfs_bnode_put(node);
	347	return;
	348	}
	349	len = hfs_brec_lenoff(node, 0, &off);
	350	}
	351	off += node->page_offset + nidx / 8;
09cbfeaf	352	page = node->page[off >> PAGE_SHIFT];
1da177e4	353	data = kmap(page);
09cbfeaf	354	off &= ~PAGE_MASK;
1da177e4 LT	355	m = 1 << (~nidx & 7);
	356	byte = data[off];
	357	if (!(byte & m)) {
d6142673 JP	358	pr_crit("trying to free free bnode %u(%d)\n",
d6142673 JP	359	node->this, node->type);
1da177e4 LT	360	kunmap(page);
	361	hfs_bnode_put(node);
	362	return;
	363	}
	364	data[off] = byte & ~m;
	365	set_page_dirty(page);
	366	kunmap(page);
	367	hfs_bnode_put(node);
	368	tree->free_nodes++;
	369	mark_inode_dirty(tree->inode);
	370	}