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

/*
 *  linux/fs/hfsplus/bfind.c
 *
 * Copyright (C) 2001
 * Brad Boyer ([email protected])
 * (C) 2003 Ardis Technologies <[email protected]>
 *
 * 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;
	hfs_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);
	hfs_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;
	__be32 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 {
		cur_cnid = 0;	/* used-uninitialized warning */
		search_cnid = 0;
		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;

	BUG_ON(!rec_found);
	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:
	pr_err("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 ([email protected])
	6	* (C) 2003 Ardis Technologies <[email protected]>
	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;
c2b3e1f7	25	hfs_dbg(BNODE_REFS, "find_init: %d (%p)\n",
2753cc28	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);
c2b3e1f7	47	hfs_dbg(BNODE_REFS, "find_exit: %d (%p)\n",
2753cc28	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	{
5f3726f9 VD	59	__be32 cur_cnid;
5f3726f9 VD	60	__be32 search_cnid;
324ef39a VD	61
	62	if (bnode->tree->cnid == HFSPLUS_EXT_CNID) {
	63	cur_cnid = fd->key->ext.cnid;
	64	search_cnid = fd->search_key->ext.cnid;
	65	} else if (bnode->tree->cnid == HFSPLUS_CAT_CNID) {
	66	cur_cnid = fd->key->cat.parent;
	67	search_cnid = fd->search_key->cat.parent;
	68	} else if (bnode->tree->cnid == HFSPLUS_ATTR_CNID) {
	69	cur_cnid = fd->key->attr.cnid;
	70	search_cnid = fd->search_key->attr.cnid;
5f3726f9 VD	71	} else {
	72	cur_cnid = 0; /* used-uninitialized warning */
	73	search_cnid = 0;
324ef39a	74	BUG();
5f3726f9	75	}
324ef39a VD	76
	77	if (cur_cnid == search_cnid) {
	78	(end) = (cur_rec);
	79	if ((begin) == (end))
	80	return 1;
	81	} else {
	82	if (be32_to_cpu(cur_cnid) < be32_to_cpu(search_cnid))
	83	(begin) = (cur_rec) + 1;
	84	else
	85	(end) = (cur_rec) - 1;
	86	}
	87
	88	return 0;
	89	}
	90
	91	int hfs_find_rec_by_key(struct hfs_bnode *bnode,
	92	struct hfs_find_data *fd,
	93	int *begin,
	94	int *end,
	95	int *cur_rec)
1da177e4 LT	96	{
1da177e4 LT	97	int cmpval;
324ef39a VD	98
	99	cmpval = bnode->tree->keycmp(fd->key, fd->search_key);
	100	if (!cmpval) {
	101	(end) = (cur_rec);
	102	return 1;
	103	}
	104	if (cmpval < 0)
	105	(begin) = (cur_rec) + 1;
	106	else
	107	(end) = (cur_rec) - 1;
	108
	109	return 0;
	110	}
	111
	112	/* Find the record in bnode that best matches key (not greater than...)*/
	113	int __hfs_brec_find(struct hfs_bnode bnode, struct hfs_find_data fd,
	114	search_strategy_t rec_found)
	115	{
1da177e4 LT	116	u16 off, len, keylen;
	117	int rec;
	118	int b, e;
	119	int res;
	120
7ce844a2	121	BUG_ON(!rec_found);
1da177e4 LT	122	b = 0;
	123	e = bnode->num_recs - 1;
	124	res = -ENOENT;
	125	do {
	126	rec = (e + b) / 2;
	127	len = hfs_brec_lenoff(bnode, rec, &off);
	128	keylen = hfs_brec_keylen(bnode, rec);
9250f925 ES	129	if (keylen == 0) {
	130	res = -EINVAL;
	131	goto fail;
	132	}
1da177e4	133	hfs_bnode_read(bnode, fd->key, off, keylen);
324ef39a	134	if (rec_found(bnode, fd, &b, &e, &rec)) {
1da177e4 LT	135	res = 0;
	136	goto done;
	137	}
1da177e4	138	} while (b <= e);
324ef39a	139
1da177e4 LT	140	if (rec != e && e >= 0) {
	141	len = hfs_brec_lenoff(bnode, e, &off);
	142	keylen = hfs_brec_keylen(bnode, e);
9250f925 ES	143	if (keylen == 0) {
	144	res = -EINVAL;
	145	goto fail;
	146	}
1da177e4 LT	147	hfs_bnode_read(bnode, fd->key, off, keylen);
1da177e4 LT	148	}
324ef39a	149
1da177e4 LT	150	done:
	151	fd->record = e;
	152	fd->keyoffset = off;
	153	fd->keylength = keylen;
	154	fd->entryoffset = off + keylen;
	155	fd->entrylength = len - keylen;
324ef39a	156
9250f925	157	fail:
1da177e4 LT	158	return res;
	159	}
	160
	161	/* Traverse a BTree from the root to a leaf finding best fit to key /
	162	/* Return allocated copy of node found, set recnum to best record */
324ef39a	163	int hfs_brec_find(struct hfs_find_data *fd, search_strategy_t do_key_compare)
1da177e4 LT	164	{
	165	struct hfs_btree *tree;
	166	struct hfs_bnode *bnode;
	167	u32 nidx, parent;
	168	__be32 data;
	169	int height, res;
	170
	171	tree = fd->tree;
	172	if (fd->bnode)
	173	hfs_bnode_put(fd->bnode);
	174	fd->bnode = NULL;
	175	nidx = tree->root;
	176	if (!nidx)
	177	return -ENOENT;
	178	height = tree->depth;
	179	res = 0;
	180	parent = 0;
	181	for (;;) {
	182	bnode = hfs_bnode_find(tree, nidx);
	183	if (IS_ERR(bnode)) {
	184	res = PTR_ERR(bnode);
	185	bnode = NULL;
	186	break;
	187	}
	188	if (bnode->height != height)
	189	goto invalid;
	190	if (bnode->type != (--height ? HFS_NODE_INDEX : HFS_NODE_LEAF))
	191	goto invalid;
	192	bnode->parent = parent;
	193
324ef39a	194	res = __hfs_brec_find(bnode, fd, do_key_compare);
1da177e4 LT	195	if (!height)
	196	break;
	197	if (fd->record < 0)
	198	goto release;
	199
	200	parent = nidx;
	201	hfs_bnode_read(bnode, &data, fd->entryoffset, 4);
	202	nidx = be32_to_cpu(data);
	203	hfs_bnode_put(bnode);
	204	}
	205	fd->bnode = bnode;
	206	return res;
	207
	208	invalid:
d6142673	209	pr_err("inconsistency in B*Tree (%d,%d,%d,%u,%u)\n",
1da177e4 LT	210	height, bnode->height, bnode->type, nidx, parent);
	211	res = -EIO;
	212	release:
	213	hfs_bnode_put(bnode);
	214	return res;
	215	}
	216
	217	int hfs_brec_read(struct hfs_find_data fd, void rec, int rec_len)
	218	{
	219	int res;
	220
324ef39a	221	res = hfs_brec_find(fd, hfs_find_rec_by_key);
1da177e4 LT	222	if (res)
	223	return res;
	224	if (fd->entrylength > rec_len)
	225	return -EINVAL;
	226	hfs_bnode_read(fd->bnode, rec, fd->entryoffset, fd->entrylength);
	227	return 0;
	228	}
	229
	230	int hfs_brec_goto(struct hfs_find_data *fd, int cnt)
	231	{
	232	struct hfs_btree *tree;
	233	struct hfs_bnode *bnode;
	234	int idx, res = 0;
	235	u16 off, len, keylen;
	236
	237	bnode = fd->bnode;
	238	tree = bnode->tree;
	239
	240	if (cnt < 0) {
	241	cnt = -cnt;
	242	while (cnt > fd->record) {
	243	cnt -= fd->record + 1;
	244	fd->record = bnode->num_recs - 1;
	245	idx = bnode->prev;
	246	if (!idx) {
	247	res = -ENOENT;
	248	goto out;
	249	}
	250	hfs_bnode_put(bnode);
	251	bnode = hfs_bnode_find(tree, idx);
	252	if (IS_ERR(bnode)) {
	253	res = PTR_ERR(bnode);
	254	bnode = NULL;
	255	goto out;
	256	}
	257	}
	258	fd->record -= cnt;
	259	} else {
	260	while (cnt >= bnode->num_recs - fd->record) {
	261	cnt -= bnode->num_recs - fd->record;
	262	fd->record = 0;
	263	idx = bnode->next;
	264	if (!idx) {
	265	res = -ENOENT;
	266	goto out;
	267	}
	268	hfs_bnode_put(bnode);
	269	bnode = hfs_bnode_find(tree, idx);
	270	if (IS_ERR(bnode)) {
	271	res = PTR_ERR(bnode);
	272	bnode = NULL;
	273	goto out;
	274	}
	275	}
	276	fd->record += cnt;
	277	}
	278
	279	len = hfs_brec_lenoff(bnode, fd->record, &off);
	280	keylen = hfs_brec_keylen(bnode, fd->record);
9250f925 ES	281	if (keylen == 0) {
	282	res = -EINVAL;
	283	goto out;
	284	}
1da177e4 LT	285	fd->keyoffset = off;
	286	fd->keylength = keylen;
	287	fd->entryoffset = off + keylen;
	288	fd->entrylength = len - keylen;
	289	hfs_bnode_read(bnode, fd->key, off, keylen);
	290	out:
	291	fd->bnode = bnode;
	292	return res;
	293	}