[deliverable/linux.git] / fs / hfsplus / bfind.c

/*
 *  linux/fs/hfsplus/bfind.c
 *
 * Copyright (C) 2001
 * Brad Boyer (flar@allandria.com)
 * (C) 2003 Ardis Technologies <roman@ardistech.com>
 *
 * Search routines for btrees
 */

#include <linux/slab.h>
#include "hfsplus_fs.h"

int hfs_find_init(struct hfs_btree *tree, struct hfs_find_data *fd)
{
	void *ptr;

	fd->tree = tree;
	fd->bnode = NULL;
	ptr = kmalloc(tree->max_key_len * 2 + 4, GFP_KERNEL);
	if (!ptr)
		return -ENOMEM;
	fd->search_key = ptr;
	fd->key = ptr + tree->max_key_len + 2;
	dprint(DBG_BNODE_REFS, "find_init: %d (%p)\n",
		tree->cnid, __builtin_return_address(0));
	switch (tree->cnid) {
	case HFSPLUS_CAT_CNID:
		mutex_lock_nested(&tree->tree_lock, CATALOG_BTREE_MUTEX);
		break;
	case HFSPLUS_EXT_CNID:
		mutex_lock_nested(&tree->tree_lock, EXTENTS_BTREE_MUTEX);
		break;
	case HFSPLUS_ATTR_CNID:
		mutex_lock_nested(&tree->tree_lock, ATTR_BTREE_MUTEX);
		break;
	default:
		BUG();
	}
	return 0;
}

void hfs_find_exit(struct hfs_find_data *fd)
{
	hfs_bnode_put(fd->bnode);
	kfree(fd->search_key);
	dprint(DBG_BNODE_REFS, "find_exit: %d (%p)\n",
		fd->tree->cnid, __builtin_return_address(0));
	mutex_unlock(&fd->tree->tree_lock);
	fd->tree = NULL;
}

int hfs_find_1st_rec_by_cnid(struct hfs_bnode *bnode,
				struct hfs_find_data *fd,
				int *begin,
				int *end,
				int *cur_rec)
{
	__be32 cur_cnid, search_cnid;

	if (bnode->tree->cnid == HFSPLUS_EXT_CNID) {
		cur_cnid = fd->key->ext.cnid;
		search_cnid = fd->search_key->ext.cnid;
	} else if (bnode->tree->cnid == HFSPLUS_CAT_CNID) {
		cur_cnid = fd->key->cat.parent;
		search_cnid = fd->search_key->cat.parent;
	} else if (bnode->tree->cnid == HFSPLUS_ATTR_CNID) {
		cur_cnid = fd->key->attr.cnid;
		search_cnid = fd->search_key->attr.cnid;
	} else
		BUG();

	if (cur_cnid == search_cnid) {
		(*end) = (*cur_rec);
		if ((*begin) == (*end))
			return 1;
	} else {
		if (be32_to_cpu(cur_cnid) < be32_to_cpu(search_cnid))
			(*begin) = (*cur_rec) + 1;
		else
			(*end) = (*cur_rec) - 1;
	}

	return 0;
}

int hfs_find_rec_by_key(struct hfs_bnode *bnode,
				struct hfs_find_data *fd,
				int *begin,
				int *end,
				int *cur_rec)
{
	int cmpval;

	cmpval = bnode->tree->keycmp(fd->key, fd->search_key);
	if (!cmpval) {
		(*end) = (*cur_rec);
		return 1;
	}
	if (cmpval < 0)
		(*begin) = (*cur_rec) + 1;
	else
		*(end) = (*cur_rec) - 1;

	return 0;
}

/* Find the record in bnode that best matches key (not greater than...)*/
int __hfs_brec_find(struct hfs_bnode *bnode, struct hfs_find_data *fd,
					search_strategy_t rec_found)
{
	u16 off, len, keylen;
	int rec;
	int b, e;
	int res;

	if (!rec_found)
		BUG();

	b = 0;
	e = bnode->num_recs - 1;
	res = -ENOENT;
	do {
		rec = (e + b) / 2;
		len = hfs_brec_lenoff(bnode, rec, &off);
		keylen = hfs_brec_keylen(bnode, rec);
		if (keylen == 0) {
			res = -EINVAL;
			goto fail;
		}
		hfs_bnode_read(bnode, fd->key, off, keylen);
		if (rec_found(bnode, fd, &b, &e, &rec)) {
			res = 0;
			goto done;
		}
	} while (b <= e);

	if (rec != e && e >= 0) {
		len = hfs_brec_lenoff(bnode, e, &off);
		keylen = hfs_brec_keylen(bnode, e);
		if (keylen == 0) {
			res = -EINVAL;
			goto fail;
		}
		hfs_bnode_read(bnode, fd->key, off, keylen);
	}

done:
	fd->record = e;
	fd->keyoffset = off;
	fd->keylength = keylen;
	fd->entryoffset = off + keylen;
	fd->entrylength = len - keylen;

fail:
	return res;
}

/* Traverse a B*Tree from the root to a leaf finding best fit to key */
/* Return allocated copy of node found, set recnum to best record */
int hfs_brec_find(struct hfs_find_data *fd, search_strategy_t do_key_compare)
{
	struct hfs_btree *tree;
	struct hfs_bnode *bnode;
	u32 nidx, parent;
	__be32 data;
	int height, res;

	tree = fd->tree;
	if (fd->bnode)
		hfs_bnode_put(fd->bnode);
	fd->bnode = NULL;
	nidx = tree->root;
	if (!nidx)
		return -ENOENT;
	height = tree->depth;
	res = 0;
	parent = 0;
	for (;;) {
		bnode = hfs_bnode_find(tree, nidx);
		if (IS_ERR(bnode)) {
			res = PTR_ERR(bnode);
			bnode = NULL;
			break;
		}
		if (bnode->height != height)
			goto invalid;
		if (bnode->type != (--height ? HFS_NODE_INDEX : HFS_NODE_LEAF))
			goto invalid;
		bnode->parent = parent;

		res = __hfs_brec_find(bnode, fd, do_key_compare);
		if (!height)
			break;
		if (fd->record < 0)
			goto release;

		parent = nidx;
		hfs_bnode_read(bnode, &data, fd->entryoffset, 4);
		nidx = be32_to_cpu(data);
		hfs_bnode_put(bnode);
	}
	fd->bnode = bnode;
	return res;

invalid:
	printk(KERN_ERR "hfs: inconsistency in B*Tree (%d,%d,%d,%u,%u)\n",
		height, bnode->height, bnode->type, nidx, parent);
	res = -EIO;
release:
	hfs_bnode_put(bnode);
	return res;
}

int hfs_brec_read(struct hfs_find_data *fd, void *rec, int rec_len)
{
	int res;

	res = hfs_brec_find(fd, hfs_find_rec_by_key);
	if (res)
		return res;
	if (fd->entrylength > rec_len)
		return -EINVAL;
	hfs_bnode_read(fd->bnode, rec, fd->entryoffset, fd->entrylength);
	return 0;
}

int hfs_brec_goto(struct hfs_find_data *fd, int cnt)
{
	struct hfs_btree *tree;
	struct hfs_bnode *bnode;
	int idx, res = 0;
	u16 off, len, keylen;

	bnode = fd->bnode;
	tree = bnode->tree;

	if (cnt < 0) {
		cnt = -cnt;
		while (cnt > fd->record) {
			cnt -= fd->record + 1;
			fd->record = bnode->num_recs - 1;
			idx = bnode->prev;
			if (!idx) {
				res = -ENOENT;
				goto out;
			}
			hfs_bnode_put(bnode);
			bnode = hfs_bnode_find(tree, idx);
			if (IS_ERR(bnode)) {
				res = PTR_ERR(bnode);
				bnode = NULL;
				goto out;
			}
		}
		fd->record -= cnt;
	} else {
		while (cnt >= bnode->num_recs - fd->record) {
			cnt -= bnode->num_recs - fd->record;
			fd->record = 0;
			idx = bnode->next;
			if (!idx) {
				res = -ENOENT;
				goto out;
			}
			hfs_bnode_put(bnode);
			bnode = hfs_bnode_find(tree, idx);
			if (IS_ERR(bnode)) {
				res = PTR_ERR(bnode);
				bnode = NULL;
				goto out;
			}
		}
		fd->record += cnt;
	}

	len = hfs_brec_lenoff(bnode, fd->record, &off);
	keylen = hfs_brec_keylen(bnode, fd->record);
	if (keylen == 0) {
		res = -EINVAL;
		goto out;
	}
	fd->keyoffset = off;
	fd->keylength = keylen;
	fd->entryoffset = off + keylen;
	fd->entrylength = len - keylen;
	hfs_bnode_read(bnode, fd->key, off, keylen);
out:
	fd->bnode = bnode;
	return res;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/fs/hfsplus/bfind.c
	3	*
	4	* Copyright (C) 2001
	5	* Brad Boyer (flar@allandria.com)
	6	* (C) 2003 Ardis Technologies <roman@ardistech.com>
	7	*
	8	* Search routines for btrees
	9	*/
	10
	11	#include <linux/slab.h>
	12	#include "hfsplus_fs.h"
	13
	14	int hfs_find_init(struct hfs_btree tree, struct hfs_find_data fd)
	15	{
	16	void *ptr;
	17
	18	fd->tree = tree;
	19	fd->bnode = NULL;
	20	ptr = kmalloc(tree->max_key_len * 2 + 4, GFP_KERNEL);
	21	if (!ptr)
	22	return -ENOMEM;
	23	fd->search_key = ptr;
	24	fd->key = ptr + tree->max_key_len + 2;
2753cc28 AS	25	dprint(DBG_BNODE_REFS, "find_init: %d (%p)\n",
2753cc28 AS	26	tree->cnid, __builtin_return_address(0));
324ef39a VD	27	switch (tree->cnid) {
	28	case HFSPLUS_CAT_CNID:
	29	mutex_lock_nested(&tree->tree_lock, CATALOG_BTREE_MUTEX);
	30	break;
	31	case HFSPLUS_EXT_CNID:
	32	mutex_lock_nested(&tree->tree_lock, EXTENTS_BTREE_MUTEX);
	33	break;
	34	case HFSPLUS_ATTR_CNID:
	35	mutex_lock_nested(&tree->tree_lock, ATTR_BTREE_MUTEX);
	36	break;
	37	default:
	38	BUG();
	39	}
1da177e4 LT	40	return 0;
	41	}
	42
	43	void hfs_find_exit(struct hfs_find_data *fd)
	44	{
	45	hfs_bnode_put(fd->bnode);
	46	kfree(fd->search_key);
2753cc28 AS	47	dprint(DBG_BNODE_REFS, "find_exit: %d (%p)\n",
2753cc28 AS	48	fd->tree->cnid, __builtin_return_address(0));
467c3d9c	49	mutex_unlock(&fd->tree->tree_lock);
1da177e4 LT	50	fd->tree = NULL;
	51	}
	52
324ef39a VD	53	int hfs_find_1st_rec_by_cnid(struct hfs_bnode *bnode,
	54	struct hfs_find_data *fd,
	55	int *begin,
	56	int *end,
	57	int *cur_rec)
	58	{
	59	__be32 cur_cnid, search_cnid;
	60
	61	if (bnode->tree->cnid == HFSPLUS_EXT_CNID) {
	62	cur_cnid = fd->key->ext.cnid;
	63	search_cnid = fd->search_key->ext.cnid;
	64	} else if (bnode->tree->cnid == HFSPLUS_CAT_CNID) {
	65	cur_cnid = fd->key->cat.parent;
	66	search_cnid = fd->search_key->cat.parent;
	67	} else if (bnode->tree->cnid == HFSPLUS_ATTR_CNID) {
	68	cur_cnid = fd->key->attr.cnid;
	69	search_cnid = fd->search_key->attr.cnid;
	70	} else
	71	BUG();
	72
	73	if (cur_cnid == search_cnid) {
	74	(end) = (cur_rec);
	75	if ((begin) == (end))
	76	return 1;
	77	} else {
	78	if (be32_to_cpu(cur_cnid) < be32_to_cpu(search_cnid))
	79	(begin) = (cur_rec) + 1;
	80	else
	81	(end) = (cur_rec) - 1;
	82	}
	83
	84	return 0;
	85	}
	86
	87	int hfs_find_rec_by_key(struct hfs_bnode *bnode,
	88	struct hfs_find_data *fd,
	89	int *begin,
	90	int *end,
	91	int *cur_rec)
1da177e4 LT	92	{
1da177e4 LT	93	int cmpval;
324ef39a VD	94
	95	cmpval = bnode->tree->keycmp(fd->key, fd->search_key);
	96	if (!cmpval) {
	97	(end) = (cur_rec);
	98	return 1;
	99	}
	100	if (cmpval < 0)
	101	(begin) = (cur_rec) + 1;
	102	else
	103	(end) = (cur_rec) - 1;
	104
	105	return 0;
	106	}
	107
	108	/* Find the record in bnode that best matches key (not greater than...)*/
	109	int __hfs_brec_find(struct hfs_bnode bnode, struct hfs_find_data fd,
	110	search_strategy_t rec_found)
	111	{
1da177e4 LT	112	u16 off, len, keylen;
	113	int rec;
	114	int b, e;
	115	int res;
	116
324ef39a VD	117	if (!rec_found)
	118	BUG();
	119
1da177e4 LT	120	b = 0;
	121	e = bnode->num_recs - 1;
	122	res = -ENOENT;
	123	do {
	124	rec = (e + b) / 2;
	125	len = hfs_brec_lenoff(bnode, rec, &off);
	126	keylen = hfs_brec_keylen(bnode, rec);
9250f925 ES	127	if (keylen == 0) {
	128	res = -EINVAL;
	129	goto fail;
	130	}
1da177e4	131	hfs_bnode_read(bnode, fd->key, off, keylen);
324ef39a	132	if (rec_found(bnode, fd, &b, &e, &rec)) {
1da177e4 LT	133	res = 0;
	134	goto done;
	135	}
1da177e4	136	} while (b <= e);
324ef39a	137
1da177e4 LT	138	if (rec != e && e >= 0) {
	139	len = hfs_brec_lenoff(bnode, e, &off);
	140	keylen = hfs_brec_keylen(bnode, e);
9250f925 ES	141	if (keylen == 0) {
	142	res = -EINVAL;
	143	goto fail;
	144	}
1da177e4 LT	145	hfs_bnode_read(bnode, fd->key, off, keylen);
1da177e4 LT	146	}
324ef39a	147
1da177e4 LT	148	done:
	149	fd->record = e;
	150	fd->keyoffset = off;
	151	fd->keylength = keylen;
	152	fd->entryoffset = off + keylen;
	153	fd->entrylength = len - keylen;
324ef39a	154
9250f925	155	fail:
1da177e4 LT	156	return res;
	157	}
	158
	159	/* Traverse a BTree from the root to a leaf finding best fit to key /
	160	/* Return allocated copy of node found, set recnum to best record */
324ef39a	161	int hfs_brec_find(struct hfs_find_data *fd, search_strategy_t do_key_compare)
1da177e4 LT	162	{
	163	struct hfs_btree *tree;
	164	struct hfs_bnode *bnode;
	165	u32 nidx, parent;
	166	__be32 data;
	167	int height, res;
	168
	169	tree = fd->tree;
	170	if (fd->bnode)
	171	hfs_bnode_put(fd->bnode);
	172	fd->bnode = NULL;
	173	nidx = tree->root;
	174	if (!nidx)
	175	return -ENOENT;
	176	height = tree->depth;
	177	res = 0;
	178	parent = 0;
	179	for (;;) {
	180	bnode = hfs_bnode_find(tree, nidx);
	181	if (IS_ERR(bnode)) {
	182	res = PTR_ERR(bnode);
	183	bnode = NULL;
	184	break;
	185	}
	186	if (bnode->height != height)
	187	goto invalid;
	188	if (bnode->type != (--height ? HFS_NODE_INDEX : HFS_NODE_LEAF))
	189	goto invalid;
	190	bnode->parent = parent;
	191
324ef39a	192	res = __hfs_brec_find(bnode, fd, do_key_compare);
1da177e4 LT	193	if (!height)
	194	break;
	195	if (fd->record < 0)
	196	goto release;
	197
	198	parent = nidx;
	199	hfs_bnode_read(bnode, &data, fd->entryoffset, 4);
	200	nidx = be32_to_cpu(data);
	201	hfs_bnode_put(bnode);
	202	}
	203	fd->bnode = bnode;
	204	return res;
	205
	206	invalid:
634725a9	207	printk(KERN_ERR "hfs: inconsistency in B*Tree (%d,%d,%d,%u,%u)\n",
1da177e4 LT	208	height, bnode->height, bnode->type, nidx, parent);
	209	res = -EIO;
	210	release:
	211	hfs_bnode_put(bnode);
	212	return res;
	213	}
	214
	215	int hfs_brec_read(struct hfs_find_data fd, void rec, int rec_len)
	216	{
	217	int res;
	218
324ef39a	219	res = hfs_brec_find(fd, hfs_find_rec_by_key);
1da177e4 LT	220	if (res)
	221	return res;
	222	if (fd->entrylength > rec_len)
	223	return -EINVAL;
	224	hfs_bnode_read(fd->bnode, rec, fd->entryoffset, fd->entrylength);
	225	return 0;
	226	}
	227
	228	int hfs_brec_goto(struct hfs_find_data *fd, int cnt)
	229	{
	230	struct hfs_btree *tree;
	231	struct hfs_bnode *bnode;
	232	int idx, res = 0;
	233	u16 off, len, keylen;
	234
	235	bnode = fd->bnode;
	236	tree = bnode->tree;
	237
	238	if (cnt < 0) {
	239	cnt = -cnt;
	240	while (cnt > fd->record) {
	241	cnt -= fd->record + 1;
	242	fd->record = bnode->num_recs - 1;
	243	idx = bnode->prev;
	244	if (!idx) {
	245	res = -ENOENT;
	246	goto out;
	247	}
	248	hfs_bnode_put(bnode);
	249	bnode = hfs_bnode_find(tree, idx);
	250	if (IS_ERR(bnode)) {
	251	res = PTR_ERR(bnode);
	252	bnode = NULL;
	253	goto out;
	254	}
	255	}
	256	fd->record -= cnt;
	257	} else {
	258	while (cnt >= bnode->num_recs - fd->record) {
	259	cnt -= bnode->num_recs - fd->record;
	260	fd->record = 0;
	261	idx = bnode->next;
	262	if (!idx) {
	263	res = -ENOENT;
	264	goto out;
	265	}
	266	hfs_bnode_put(bnode);
	267	bnode = hfs_bnode_find(tree, idx);
	268	if (IS_ERR(bnode)) {
	269	res = PTR_ERR(bnode);
	270	bnode = NULL;
	271	goto out;
	272	}
	273	}
	274	fd->record += cnt;
	275	}
	276
	277	len = hfs_brec_lenoff(bnode, fd->record, &off);
	278	keylen = hfs_brec_keylen(bnode, fd->record);
9250f925 ES	279	if (keylen == 0) {
	280	res = -EINVAL;
	281	goto out;
	282	}
1da177e4 LT	283	fd->keyoffset = off;
	284	fd->keylength = keylen;
	285	fd->entryoffset = off + keylen;
	286	fd->entrylength = len - keylen;
	287	hfs_bnode_read(bnode, fd->key, off, keylen);
	288	out:
	289	fd->bnode = bnode;
	290	return res;
	291	}