[linux-2.6-block.git] / fs / hfsplus / btree.c

/*
 *  linux/fs/hfsplus/btree.c
 *
 * Copyright (C) 2001
 * Brad Boyer (flar@allandria.com)
 * (C) 2003 Ardis Technologies <roman@ardistech.com>
 *
 * Handle opening/closing btree
 */

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

#include "hfsplus_fs.h"
#include "hfsplus_raw.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)
{
	struct hfs_btree *tree;
	struct hfs_btree_header_rec *head;
	struct address_space *mapping;
	struct inode *inode;
	struct page *page;
	unsigned int size;

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

	init_MUTEX(&tree->tree_lock);
	spin_lock_init(&tree->hash_lock);
	tree->sb = sb;
	tree->cnid = id;
	inode = hfsplus_iget(sb, id);
	if (IS_ERR(inode))
		goto free_tree;
	tree->inode = inode;

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

	/* 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);

	/* Set the correct compare function */
	if (id == HFSPLUS_EXT_CNID) {
		tree->keycmp = hfsplus_ext_cmp_key;
	} else if (id == HFSPLUS_CAT_CNID) {
		if ((HFSPLUS_SB(sb).flags & HFSPLUS_SB_HFSX) &&
		    (head->key_type == HFSPLUS_KEY_BINARY))
			tree->keycmp = hfsplus_cat_bin_cmp_key;
		else {
			tree->keycmp = hfsplus_cat_case_cmp_key;
			HFSPLUS_SB(sb).flags |= HFSPLUS_SB_CASEFOLD;
		}
	} else {
		printk(KERN_ERR "hfs: unknown B*Tree requested\n");
		goto fail_page;
	}

	size = tree->node_size;
	if (!is_power_of_2(size))
		goto fail_page;
	if (!tree->node_count)
		goto fail_page;
	tree->node_size_shift = ffs(size) - 1;

	tree->pages_per_bnode = (tree->node_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;

	kunmap(page);
	page_cache_release(page);
	return tree;

 fail_page:
	tree->inode->i_mapping->a_ops = &hfsplus_aops;
	page_cache_release(page);
 free_tree:
	iput(tree->inode);
	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))
				printk(KERN_CRIT "hfs: 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;

	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 = hfsplus_file_extend(inode);
		if (res)
			return ERR_PTR(res);
		HFSPLUS_I(inode).phys_size = inode->i_size =
				(loff_t)HFSPLUS_I(inode).alloc_blocks <<
				HFSPLUS_SB(tree->sb).alloc_blksz_shift;
		HFSPLUS_I(inode).fs_blocks = HFSPLUS_I(inode).alloc_blocks <<
					     HFSPLUS_SB(tree->sb).fs_shift;
		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_CACHE_SHIFT);
	data = kmap(*pagep);
	off &= ~PAGE_CACHE_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_CACHE_SIZE) {
				kunmap(*pagep);
				data = kmap(*++pagep);
				off = 0;
			}
			idx += 8;
			len--;
		}
		kunmap(*pagep);
		nidx = node->next;
		if (!nidx) {
			printk(KERN_DEBUG "hfs: 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_CACHE_SHIFT);
		data = kmap(*pagep);
		off &= ~PAGE_CACHE_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;

	dprint(DBG_BNODE_MOD, "btree_free_node: %u\n", node->this);
	BUG_ON(!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 */;
			printk(KERN_CRIT "hfs: 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 */;
			printk(KERN_CRIT "hfs: 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_CACHE_SHIFT];
	data = kmap(page);
	off &= ~PAGE_CACHE_MASK;
	m = 1 << (~nidx & 7);
	byte = data[off];
	if (!(byte & m)) {
		printk(KERN_CRIT "hfs: 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/hfsplus/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/slab.h>
	12	#include <linux/pagemap.h>
e1b5c1d3	13	#include <linux/log2.h>
1da177e4 LT	14
	15	#include "hfsplus_fs.h"
	16	#include "hfsplus_raw.h"
	17
	18
	19	/* Get a reference to a BTree and do some initial checks /
	20	struct hfs_btree hfs_btree_open(struct super_block sb, u32 id)
	21	{
	22	struct hfs_btree *tree;
	23	struct hfs_btree_header_rec *head;
	24	struct address_space *mapping;
63525391	25	struct inode *inode;
1da177e4 LT	26	struct page *page;
	27	unsigned int size;
	28
f8314dc6	29	tree = kzalloc(sizeof(*tree), GFP_KERNEL);
1da177e4 LT	30	if (!tree)
1da177e4 LT	31	return NULL;
1da177e4 LT	32
	33	init_MUTEX(&tree->tree_lock);
	34	spin_lock_init(&tree->hash_lock);
1da177e4 LT	35	tree->sb = sb;
1da177e4 LT	36	tree->cnid = id;
63525391 DH	37	inode = hfsplus_iget(sb, id);
63525391 DH	38	if (IS_ERR(inode))
1da177e4	39	goto free_tree;
63525391	40	tree->inode = inode;
1da177e4 LT	41
1da177e4 LT	42	mapping = tree->inode->i_mapping;
090d2b18	43	page = read_mapping_page(mapping, 0, NULL);
1da177e4 LT	44	if (IS_ERR(page))
	45	goto free_tree;
	46
	47	/* Load the header */
	48	head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc));
	49	tree->root = be32_to_cpu(head->root);
	50	tree->leaf_count = be32_to_cpu(head->leaf_count);
	51	tree->leaf_head = be32_to_cpu(head->leaf_head);
	52	tree->leaf_tail = be32_to_cpu(head->leaf_tail);
	53	tree->node_count = be32_to_cpu(head->node_count);
	54	tree->free_nodes = be32_to_cpu(head->free_nodes);
	55	tree->attributes = be32_to_cpu(head->attributes);
	56	tree->node_size = be16_to_cpu(head->node_size);
	57	tree->max_key_len = be16_to_cpu(head->max_key_len);
	58	tree->depth = be16_to_cpu(head->depth);
	59
2179d372 DE	60	/* Set the correct compare function */
	61	if (id == HFSPLUS_EXT_CNID) {
	62	tree->keycmp = hfsplus_ext_cmp_key;
	63	} else if (id == HFSPLUS_CAT_CNID) {
	64	if ((HFSPLUS_SB(sb).flags & HFSPLUS_SB_HFSX) &&
	65	(head->key_type == HFSPLUS_KEY_BINARY))
	66	tree->keycmp = hfsplus_cat_bin_cmp_key;
d45bce8f	67	else {
2179d372	68	tree->keycmp = hfsplus_cat_case_cmp_key;
d45bce8f DG	69	HFSPLUS_SB(sb).flags \|= HFSPLUS_SB_CASEFOLD;
d45bce8f DG	70	}
2179d372 DE	71	} else {
	72	printk(KERN_ERR "hfs: unknown B*Tree requested\n");
	73	goto fail_page;
	74	}
	75
1da177e4	76	size = tree->node_size;
e1b5c1d3	77	if (!is_power_of_2(size))
1da177e4 LT	78	goto fail_page;
	79	if (!tree->node_count)
	80	goto fail_page;
	81	tree->node_size_shift = ffs(size) - 1;
	82
	83	tree->pages_per_bnode = (tree->node_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
	84
	85	kunmap(page);
	86	page_cache_release(page);
	87	return tree;
	88
	89	fail_page:
	90	tree->inode->i_mapping->a_ops = &hfsplus_aops;
	91	page_cache_release(page);
	92	free_tree:
	93	iput(tree->inode);
	94	kfree(tree);
	95	return NULL;
	96	}
	97
	98	/* Release resources used by a btree */
	99	void hfs_btree_close(struct hfs_btree *tree)
	100	{
	101	struct hfs_bnode *node;
	102	int i;
	103
	104	if (!tree)
	105	return;
	106
	107	for (i = 0; i < NODE_HASH_SIZE; i++) {
	108	while ((node = tree->node_hash[i])) {
	109	tree->node_hash[i] = node->next_hash;
	110	if (atomic_read(&node->refcnt))
634725a9	111	printk(KERN_CRIT "hfs: node %d:%d still has %d user(s)!\n",
1da177e4 LT	112	node->tree->cnid, node->this, atomic_read(&node->refcnt));
	113	hfs_bnode_free(node);
	114	tree->node_hash_cnt--;
	115	}
	116	}
	117	iput(tree->inode);
	118	kfree(tree);
	119	}
	120
	121	void hfs_btree_write(struct hfs_btree *tree)
	122	{
	123	struct hfs_btree_header_rec *head;
	124	struct hfs_bnode *node;
	125	struct page *page;
	126
	127	node = hfs_bnode_find(tree, 0);
	128	if (IS_ERR(node))
	129	/* panic? */
	130	return;
	131	/* Load the header */
	132	page = node->page[0];
	133	head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc));
	134
	135	head->root = cpu_to_be32(tree->root);
	136	head->leaf_count = cpu_to_be32(tree->leaf_count);
	137	head->leaf_head = cpu_to_be32(tree->leaf_head);
	138	head->leaf_tail = cpu_to_be32(tree->leaf_tail);
	139	head->node_count = cpu_to_be32(tree->node_count);
	140	head->free_nodes = cpu_to_be32(tree->free_nodes);
	141	head->attributes = cpu_to_be32(tree->attributes);
	142	head->depth = cpu_to_be16(tree->depth);
	143
	144	kunmap(page);
	145	set_page_dirty(page);
	146	hfs_bnode_put(node);
	147	}
	148
	149	static struct hfs_bnode hfs_bmap_new_bmap(struct hfs_bnode prev, u32 idx)
	150	{
	151	struct hfs_btree *tree = prev->tree;
	152	struct hfs_bnode *node;
	153	struct hfs_bnode_desc desc;
	154	__be32 cnid;
	155
	156	node = hfs_bnode_create(tree, idx);
	157	if (IS_ERR(node))
	158	return node;
	159
	160	tree->free_nodes--;
	161	prev->next = idx;
	162	cnid = cpu_to_be32(idx);
	163	hfs_bnode_write(prev, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
	164
	165	node->type = HFS_NODE_MAP;
	166	node->num_recs = 1;
	167	hfs_bnode_clear(node, 0, tree->node_size);
	168	desc.next = 0;
	169	desc.prev = 0;
	170	desc.type = HFS_NODE_MAP;
	171	desc.height = 0;
	172	desc.num_recs = cpu_to_be16(1);
	173	desc.reserved = 0;
	174	hfs_bnode_write(node, &desc, 0, sizeof(desc));
	175	hfs_bnode_write_u16(node, 14, 0x8000);
176	hfs_bnode_write_u16(node, tree->node_size - 2, 14);
177	hfs_bnode_write_u16(node, tree->node_size - 4, tree->node_size - 6);
178
179	return node;
180	}
181
182	struct hfs_bnode hfs_bmap_alloc(struct hfs_btree tree)
183	{
184	struct hfs_bnode node, next_node;
185	struct page **pagep;
186	u32 nidx, idx;
487798df AM	187	unsigned off;
	188	u16 off16;
	189	u16 len;
1da177e4 LT	190	u8 *data, byte, m;
	191	int i;
	192
	193	while (!tree->free_nodes) {
	194	struct inode *inode = tree->inode;
	195	u32 count;
	196	int res;
	197
	198	res = hfsplus_file_extend(inode);
	199	if (res)
	200	return ERR_PTR(res);
	201	HFSPLUS_I(inode).phys_size = inode->i_size =
	202	(loff_t)HFSPLUS_I(inode).alloc_blocks <<
	203	HFSPLUS_SB(tree->sb).alloc_blksz_shift;
	204	HFSPLUS_I(inode).fs_blocks = HFSPLUS_I(inode).alloc_blocks <<
	205	HFSPLUS_SB(tree->sb).fs_shift;
	206	inode_set_bytes(inode, inode->i_size);
	207	count = inode->i_size >> tree->node_size_shift;
	208	tree->free_nodes = count - tree->node_count;
	209	tree->node_count = count;
	210	}
	211
	212	nidx = 0;
	213	node = hfs_bnode_find(tree, nidx);
	214	if (IS_ERR(node))
	215	return node;
487798df AM	216	len = hfs_brec_lenoff(node, 2, &off16);
487798df AM	217	off = off16;
1da177e4 LT	218
	219	off += node->page_offset;
	220	pagep = node->page + (off >> PAGE_CACHE_SHIFT);
	221	data = kmap(*pagep);
	222	off &= ~PAGE_CACHE_MASK;
	223	idx = 0;
	224
	225	for (;;) {
	226	while (len) {
	227	byte = data[off];
	228	if (byte != 0xff) {
	229	for (m = 0x80, i = 0; i < 8; m >>= 1, i++) {
	230	if (!(byte & m)) {
	231	idx += i;
	232	data[off] \|= m;
	233	set_page_dirty(*pagep);
	234	kunmap(*pagep);
	235	tree->free_nodes--;
	236	mark_inode_dirty(tree->inode);
	237	hfs_bnode_put(node);
1da177e4 LT	238	return hfs_bnode_create(tree, idx);
	239	}
	240	}
	241	}
	242	if (++off >= PAGE_CACHE_SIZE) {
	243	kunmap(*pagep);
	244	data = kmap(*++pagep);
	245	off = 0;
	246	}
	247	idx += 8;
	248	len--;
	249	}
	250	kunmap(*pagep);
	251	nidx = node->next;
	252	if (!nidx) {
634725a9	253	printk(KERN_DEBUG "hfs: create new bmap node...\n");
1da177e4 LT	254	next_node = hfs_bmap_new_bmap(node, idx);
	255	} else
	256	next_node = hfs_bnode_find(tree, nidx);
	257	hfs_bnode_put(node);
	258	if (IS_ERR(next_node))
	259	return next_node;
	260	node = next_node;
	261
487798df AM	262	len = hfs_brec_lenoff(node, 0, &off16);
487798df AM	263	off = off16;
1da177e4 LT	264	off += node->page_offset;
	265	pagep = node->page + (off >> PAGE_CACHE_SHIFT);
	266	data = kmap(*pagep);
	267	off &= ~PAGE_CACHE_MASK;
	268	}
	269	}
	270
	271	void hfs_bmap_free(struct hfs_bnode *node)
	272	{
	273	struct hfs_btree *tree;
	274	struct page *page;
	275	u16 off, len;
	276	u32 nidx;
	277	u8 *data, byte, m;
	278
	279	dprint(DBG_BNODE_MOD, "btree_free_node: %u\n", node->this);
0bf3ba53	280	BUG_ON(!node->this);
1da177e4 LT	281	tree = node->tree;
	282	nidx = node->this;
	283	node = hfs_bnode_find(tree, 0);
	284	if (IS_ERR(node))
	285	return;
	286	len = hfs_brec_lenoff(node, 2, &off);
	287	while (nidx >= len * 8) {
	288	u32 i;
	289
	290	nidx -= len * 8;
	291	i = node->next;
	292	hfs_bnode_put(node);
	293	if (!i) {
	294	/* panic */;
634725a9	295	printk(KERN_CRIT "hfs: unable to free bnode %u. bmap not found!\n", node->this);
1da177e4 LT	296	return;
	297	}
	298	node = hfs_bnode_find(tree, i);
	299	if (IS_ERR(node))
	300	return;
	301	if (node->type != HFS_NODE_MAP) {
	302	/* panic */;
634725a9	303	printk(KERN_CRIT "hfs: invalid bmap found! (%u,%d)\n", node->this, node->type);
1da177e4 LT	304	hfs_bnode_put(node);
	305	return;
	306	}
	307	len = hfs_brec_lenoff(node, 0, &off);
	308	}
	309	off += node->page_offset + nidx / 8;
	310	page = node->page[off >> PAGE_CACHE_SHIFT];
	311	data = kmap(page);
	312	off &= ~PAGE_CACHE_MASK;
	313	m = 1 << (~nidx & 7);
	314	byte = data[off];
	315	if (!(byte & m)) {
634725a9	316	printk(KERN_CRIT "hfs: trying to free free bnode %u(%d)\n", node->this, node->type);
1da177e4 LT	317	kunmap(page);
	318	hfs_bnode_put(node);
	319	return;
	320	}
	321	data[off] = byte & ~m;
	322	set_page_dirty(page);
	323	kunmap(page);
	324	hfs_bnode_put(node);
	325	tree->free_nodes++;
	326	mark_inode_dirty(tree->inode);
	327	}