[mirror_ubuntu-artful-kernel.git] / fs / hfs / btree.c

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