aboutsummaryrefslogtreecommitdiff
path: root/fs/hfs/bnode.c
blob: 0d200068d0afaff014db5279d46c74dab06332bb (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
/*
 *  linux/fs/hfs/bnode.c
 *
 * Copyright (C) 2001
 * Brad Boyer (flar@allandria.com)
 * (C) 2003 Ardis Technologies <roman@ardistech.com>
 *
 * Handle basic btree node operations
 */

#include <linux/pagemap.h>
#include <linux/swap.h>

#include "btree.h"

void hfs_bnode_read(struct hfs_bnode *node, void *buf,
		int off, int len)
{
	struct page *page;

	off += node->page_offset;
	page = node->page[0];

	memcpy(buf, kmap(page) + off, len);
	kunmap(page);
}

u16 hfs_bnode_read_u16(struct hfs_bnode *node, int off)
{
	__be16 data;
	// optimize later...
	hfs_bnode_read(node, &data, off, 2);
	return be16_to_cpu(data);
}

u8 hfs_bnode_read_u8(struct hfs_bnode *node, int off)
{
	u8 data;
	// optimize later...
	hfs_bnode_read(node, &data, off, 1);
	return data;
}

void hfs_bnode_read_key(struct hfs_bnode *node, void *key, int off)
{
	struct hfs_btree *tree;
	int key_len;

	tree = node->tree;
	if (node->type == HFS_NODE_LEAF ||
	    tree->attributes & HFS_TREE_VARIDXKEYS)
		key_len = hfs_bnode_read_u8(node, off) + 1;
	else
		key_len = tree->max_key_len + 1;

	hfs_bnode_read(node, key, off, key_len);
}

void hfs_bnode_write(struct hfs_bnode *node, void *buf, int off, int len)
{
	struct page *page;

	off += node->page_offset;
	page = node->page[0];

	memcpy(kmap(page) + off, buf, len);
	kunmap(page);
	set_page_dirty(page);
}

void hfs_bnode_write_u16(struct hfs_bnode *node, int off, u16 data)
{
	__be16 v = cpu_to_be16(data);
	// optimize later...
	hfs_bnode_write(node, &v, off, 2);
}

void hfs_bnode_write_u8(struct hfs_bnode *node, int off, u8 data)
{
	// optimize later...
	hfs_bnode_write(node, &data, off, 1);
}

void hfs_bnode_clear(struct hfs_bnode *node, int off, int len)
{
	struct page *page;

	off += node->page_offset;
	page = node->page[0];

	memset(kmap(page) + off, 0, len);
	kunmap(page);
	set_page_dirty(page);
}

void hfs_bnode_copy(struct hfs_bnode *dst_node, int dst,
		struct hfs_bnode *src_node, int src, int len)
{
	struct hfs_btree *tree;
	struct page *src_page, *dst_page;

	dprint(DBG_BNODE_MOD, "copybytes: %u,%u,%u\n", dst, src, len);
	if (!len)
		return;
	tree = src_node->tree;
	src += src_node->page_offset;
	dst += dst_node->page_offset;
	src_page = src_node->page[0];
	dst_page = dst_node->page[0];

	memcpy(kmap(dst_page) + dst, kmap(src_page) + src, len);
	kunmap(src_page);
	kunmap(dst_page);
	set_page_dirty(dst_page);
}

void hfs_bnode_move(struct hfs_bnode *node, int dst, int src, int len)
{
	struct page *page;
	void *ptr;

	dprint(DBG_BNODE_MOD, "movebytes: %u,%u,%u\n", dst, src, len);
	if (!len)
		return;
	src += node->page_offset;
	dst += node->page_offset;
	page = node->page[0];
	ptr = kmap(page);
	memmove(ptr + dst, ptr + src, len);
	kunmap(page);
	set_page_dirty(page);
}

void hfs_bnode_dump(struct hfs_bnode *node)
{
	struct hfs_bnode_desc desc;
	__be32 cnid;
	int i, off, key_off;

	dprint(DBG_BNODE_MOD, "bnode: %d\n", node->this);
	hfs_bnode_read(node, &desc, 0, sizeof(desc));
	dprint(DBG_BNODE_MOD, "%d, %d, %d, %d, %d\n",
		be32_to_cpu(desc.next), be32_to_cpu(desc.prev),
		desc.type, desc.height, be16_to_cpu(desc.num_recs));

	off = node->tree->node_size - 2;
	for (i = be16_to_cpu(desc.num_recs); i >= 0; off -= 2, i--) {
		key_off = hfs_bnode_read_u16(node, off);
		dprint(DBG_BNODE_MOD, " %d", key_off);
		if (i && node->type == HFS_NODE_INDEX) {
			int tmp;

			if (node->tree->attributes & HFS_TREE_VARIDXKEYS)
				tmp = (hfs_bnode_read_u8(node, key_off) | 1) + 1;
			else
				tmp = node->tree->max_key_len + 1;
			dprint(DBG_BNODE_MOD, " (%d,%d", tmp, hfs_bnode_read_u8(node, key_off));
			hfs_bnode_read(node, &cnid, key_off + tmp, 4);
			dprint(DBG_BNODE_MOD, ",%d)", be32_to_cpu(cnid));
		} else if (i && node->type == HFS_NODE_LEAF) {
			int tmp;

			tmp = hfs_bnode_read_u8(node, key_off);
			dprint(DBG_BNODE_MOD, " (%d)", tmp);
		}
	}
	dprint(DBG_BNODE_MOD, "\n");
}

void hfs_bnode_unlink(struct hfs_bnode *node)
{
	struct hfs_btree *tree;
	struct hfs_bnode *tmp;
	__be32 cnid;

	tree = node->tree;
	if (node->prev) {
		tmp = hfs_bnode_find(tree, node->prev);
		if (IS_ERR(tmp))
			return;
		tmp->next = node->next;
		cnid = cpu_to_be32(tmp->next);
		hfs_bnode_write(tmp, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
		hfs_bnode_put(tmp);
	} else if (node->type == HFS_NODE_LEAF)
		tree->leaf_head = node->next;

	if (node->next) {
		tmp = hfs_bnode_find(tree, node->next);
		if (IS_ERR(tmp))
			return;
		tmp->prev = node->prev;
		cnid = cpu_to_be32(tmp->prev);
		hfs_bnode_write(tmp, &cnid, offsetof(struct hfs_bnode_desc, prev), 4);
		hfs_bnode_put(tmp);
	} else if (node->type == HFS_NODE_LEAF)
		tree->leaf_tail = node->prev;

	// move down?
	if (!node->prev && !node->next) {
		printk(KERN_DEBUG "hfs_btree_del_level\n");
	}
	if (!node->parent) {
		tree->root = 0;
		tree->depth = 0;
	}
	set_bit(HFS_BNODE_DELETED, &node->flags);
}

static inline int hfs_bnode_hash(u32 num)
{
	num = (num >> 16) + num;
	num += num >> 8;
	return num & (NODE_HASH_SIZE - 1);
}

struct hfs_bnode *hfs_bnode_findhash(struct hfs_btree *tree, u32 cnid)
{
	struct hfs_bnode *node;

	if (cnid >= tree->node_count) {
		printk(KERN_ERR "hfs: request for non-existent node %d in B*Tree\n", cnid);
		return NULL;
	}

	for (node = tree->node_hash[hfs_bnode_hash(cnid)];
	     node; node = node->next_hash) {
		if (node->this == cnid) {
			return node;
		}
	}
	return NULL;
}

static struct hfs_bnode *__hfs_bnode_create(struct hfs_btree *tree, u32 cnid)
{
	struct super_block *sb;
	struct hfs_bnode *node, *node2;
	struct address_space *mapping;
	struct page *page;
	int size, block, i, hash;
	loff_t off;

	if (cnid >= tree->node_count) {
		printk(KERN_ERR "hfs: request for non-existent node %d in B*Tree\n", cnid);
		return NULL;
	}

	sb = tree->inode->i_sb;
	size = sizeof(struct hfs_bnode) + tree->pages_per_bnode *
		sizeof(struct page *);
	node = kzalloc(size, GFP_KERNEL);
	if (!node)
		return NULL;
	node->tree = tree;
	node->this = cnid;
	set_bit(HFS_BNODE_NEW, &node->flags);
	atomic_set(&node->refcnt, 1);
	dprint(DBG_BNODE_REFS, "new_node(%d:%d): 1\n",
	       node->tree->cnid, node->this);
	init_waitqueue_head(&node->lock_wq);
	spin_lock(&tree->hash_lock);
	node2 = hfs_bnode_findhash(tree, cnid);
	if (!node2) {
		hash = hfs_bnode_hash(cnid);
		node->next_hash = tree->node_hash[hash];
		tree->node_hash[hash] = node;
		tree->node_hash_cnt++;
	} else {
		spin_unlock(&tree->hash_lock);
		kfree(node);
		wait_event(node2->lock_wq, !test_bit(HFS_BNODE_NEW, &node2->flags));
		return node2;
	}
	spin_unlock(&tree->hash_lock);

	mapping = tree->inode->i_mapping;
	off = (loff_t)cnid * tree->node_size;
	block = off >> PAGE_CACHE_SHIFT;
	node->page_offset = off & ~PAGE_CACHE_MASK;
	for (i = 0; i < tree->pages_per_bnode; i++) {
		page = read_mapping_page(mapping, block++, NULL);
		if (IS_ERR(page))
			goto fail;
		if (PageError(page)) {
			page_cache_release(page);
			goto fail;
		}
		page_cache_release(page);
		node->page[i] = page;
	}

	return node;
fail:
	set_bit(HFS_BNODE_ERROR, &node->flags);
	return node;
}

void hfs_bnode_unhash(struct hfs_bnode *node)
{
	struct hfs_bnode **p;

	dprint(DBG_BNODE_REFS, "remove_node(%d:%d): %d\n",
		node->tree->cnid, node->this, atomic_read(&node->refcnt));
	for (p = &node->tree->node_hash[hfs_bnode_hash(node->this)];
	     *p && *p != node; p = &(*p)->next_hash)
		;
	BUG_ON(!*p);
	*p = node->next_hash;
	node->tree->node_hash_cnt--;
}

/* Load a particular node out of a tree */
struct hfs_bnode *hfs_bnode_find(struct hfs_btree *tree, u32 num)
{
	struct hfs_bnode *node;
	struct hfs_bnode_desc *desc;
	int i, rec_off, off, next_off;
	int entry_size, key_size;

	spin_lock(&tree->hash_lock);
	node = hfs_bnode_findhash(tree, num);
	if (node) {
		hfs_bnode_get(node);
		spin_unlock(&tree->hash_lock);
		wait_event(node->lock_wq, !test_bit(HFS_BNODE_NEW, &node->flags));
		if (test_bit(HFS_BNODE_ERROR, &node->flags))
			goto node_error;
		return node;
	}
	spin_unlock(&tree->hash_lock);
	node = __hfs_bnode_create(tree, num);
	if (!node)
		return ERR_PTR(-ENOMEM);
	if (test_bit(HFS_BNODE_ERROR, &node->flags))
		goto node_error;
	if (!test_bit(HFS_BNODE_NEW, &node->flags))
		return node;

	desc = (struct hfs_bnode_desc *)(kmap(node->page[0]) + node->page_offset);
	node->prev = be32_to_cpu(desc->prev);
	node->next = be32_to_cpu(desc->next);
	node->num_recs = be16_to_cpu(desc->num_recs);
	node->type = desc->type;
	node->height = desc->height;
	kunmap(node->page[0]);

	switch (node->type) {
	case HFS_NODE_HEADER:
	case HFS_NODE_MAP:
		if (node->height != 0)
			goto node_error;
		break;
	case HFS_NODE_LEAF:
		if (node->height != 1)
			goto node_error;
		break;
	case HFS_NODE_INDEX:
		if (node->height <= 1 || node->height > tree->depth)
			goto node_error;
		break;
	default:
		goto node_error;
	}

	rec_off = tree->node_size - 2;
	off = hfs_bnode_read_u16(node, rec_off);
	if (off != sizeof(struct hfs_bnode_desc))
		goto node_error;
	for (i = 1; i <= node->num_recs; off = next_off, i++) {
		rec_off -= 2;
		next_off = hfs_bnode_read_u16(node, rec_off);
		if (next_off <= off ||
		    next_off > tree->node_size ||
		    next_off & 1)
			goto node_error;
		entry_size = next_off - off;
		if (node->type != HFS_NODE_INDEX &&
		    node->type != HFS_NODE_LEAF)
			continue;
		key_size = hfs_bnode_read_u8(node, off) + 1;
		if (key_size >= entry_size /*|| key_size & 1*/)
			goto node_error;
	}
	clear_bit(HFS_BNODE_NEW, &node->flags);
	wake_up(&node->lock_wq);
	return node;

node_error:
	set_bit(HFS_BNODE_ERROR, &node->flags);
	clear_bit(HFS_BNODE_NEW, &node->flags);
	wake_up(&node->lock_wq);
	hfs_bnode_put(node);
	return ERR_PTR(-EIO);
}

void hfs_bnode_free(struct hfs_bnode *node)
{
	//int i;

	//for (i = 0; i < node->tree->pages_per_bnode; i++)
	//	if (node->page[i])
	//		page_cache_release(node->page[i]);
	kfree(node);
}

struct hfs_bnode *hfs_bnode_create(struct hfs_btree *tree, u32 num)
{
	struct hfs_bnode *node;
	struct page **pagep;
	int i;

	spin_lock(&tree->hash_lock);
	node = hfs_bnode_findhash(tree, num);
	spin_unlock(&tree->hash_lock);
	BUG_ON(node);
	node = __hfs_bnode_create(tree, num);
	if (!node)
		return ERR_PTR(-ENOMEM);
	if (test_bit(HFS_BNODE_ERROR, &node->flags)) {
		hfs_bnode_put(node);
		return ERR_PTR(-EIO);
	}

	pagep = node->page;
	memset(kmap(*pagep) + node->page_offset, 0,
	       min((int)PAGE_CACHE_SIZE, (int)tree->node_size));
	set_page_dirty(*pagep);
	kunmap(*pagep);
	for (i = 1; i < tree->pages_per_bnode; i++) {
		memset(kmap(*++pagep), 0, PAGE_CACHE_SIZE);
		set_page_dirty(*pagep);
		kunmap(*pagep);
	}
	clear_bit(HFS_BNODE_NEW, &node->flags);
	wake_up(&node->lock_wq);

	return node;
}

void hfs_bnode_get(struct hfs_bnode *node)
{
	if (node) {
		atomic_inc(&node->refcnt);
		dprint(DBG_BNODE_REFS, "get_node(%d:%d): %d\n",
		       node->tree->cnid, node->this, atomic_read(&node->refcnt));
	}
}

/* Dispose of resources used by a node */
void hfs_bnode_put(struct hfs_bnode *node)
{
	if (node) {
		struct hfs_btree *tree = node->tree;
		int i;

		dprint(DBG_BNODE_REFS, "put_node(%d:%d): %d\n",
		       node->tree->cnid, node->this, atomic_read(&node->refcnt));
		BUG_ON(!atomic_read(&node->refcnt));
		if (!atomic_dec_and_lock(&node->refcnt, &tree->hash_lock))
			return;
		for (i = 0; i < tree->pages_per_bnode; i++) {
			if (!node->page[i])
				continue;
			mark_page_accessed(node->page[i]);
		}

		if (test_bit(HFS_BNODE_DELETED, &node->flags)) {
			hfs_bnode_unhash(node);
			spin_unlock(&tree->hash_lock);
			hfs_bmap_free(node);
			hfs_bnode_free(node);
			return;
		}
		spin_unlock(&tree->hash_lock);
	}
}