xref: /openbmc/linux/fs/hfs/bnode.c (revision 87c2ce3b) 
1 /*
2  *  linux/fs/hfs/bnode.c
3  *
4  * Copyright (C) 2001
5  * Brad Boyer (flar@allandria.com)
6  * (C) 2003 Ardis Technologies <roman@ardistech.com>
7  *
8  * Handle basic btree node operations
9  */
10 
11 #include <linux/pagemap.h>
12 #include <linux/swap.h>
13 
14 #include "btree.h"
15 
16 void hfs_bnode_read(struct hfs_bnode *node, void *buf,
17 		int off, int len)
18 {
19 	struct page *page;
20 
21 	off += node->page_offset;
22 	page = node->page[0];
23 
24 	memcpy(buf, kmap(page) + off, len);
25 	kunmap(page);
26 }
27 
28 u16 hfs_bnode_read_u16(struct hfs_bnode *node, int off)
29 {
30 	__be16 data;
31 	// optimize later...
32 	hfs_bnode_read(node, &data, off, 2);
33 	return be16_to_cpu(data);
34 }
35 
36 u8 hfs_bnode_read_u8(struct hfs_bnode *node, int off)
37 {
38 	u8 data;
39 	// optimize later...
40 	hfs_bnode_read(node, &data, off, 1);
41 	return data;
42 }
43 
44 void hfs_bnode_read_key(struct hfs_bnode *node, void *key, int off)
45 {
46 	struct hfs_btree *tree;
47 	int key_len;
48 
49 	tree = node->tree;
50 	if (node->type == HFS_NODE_LEAF ||
51 	    tree->attributes & HFS_TREE_VARIDXKEYS)
52 		key_len = hfs_bnode_read_u8(node, off) + 1;
53 	else
54 		key_len = tree->max_key_len + 1;
55 
56 	hfs_bnode_read(node, key, off, key_len);
57 }
58 
59 void hfs_bnode_write(struct hfs_bnode *node, void *buf, int off, int len)
60 {
61 	struct page *page;
62 
63 	off += node->page_offset;
64 	page = node->page[0];
65 
66 	memcpy(kmap(page) + off, buf, len);
67 	kunmap(page);
68 	set_page_dirty(page);
69 }
70 
71 void hfs_bnode_write_u16(struct hfs_bnode *node, int off, u16 data)
72 {
73 	__be16 v = cpu_to_be16(data);
74 	// optimize later...
75 	hfs_bnode_write(node, &v, off, 2);
76 }
77 
78 void hfs_bnode_write_u8(struct hfs_bnode *node, int off, u8 data)
79 {
80 	// optimize later...
81 	hfs_bnode_write(node, &data, off, 1);
82 }
83 
84 void hfs_bnode_clear(struct hfs_bnode *node, int off, int len)
85 {
86 	struct page *page;
87 
88 	off += node->page_offset;
89 	page = node->page[0];
90 
91 	memset(kmap(page) + off, 0, len);
92 	kunmap(page);
93 	set_page_dirty(page);
94 }
95 
96 void hfs_bnode_copy(struct hfs_bnode *dst_node, int dst,
97 		struct hfs_bnode *src_node, int src, int len)
98 {
99 	struct hfs_btree *tree;
100 	struct page *src_page, *dst_page;
101 
102 	dprint(DBG_BNODE_MOD, "copybytes: %u,%u,%u\n", dst, src, len);
103 	if (!len)
104 		return;
105 	tree = src_node->tree;
106 	src += src_node->page_offset;
107 	dst += dst_node->page_offset;
108 	src_page = src_node->page[0];
109 	dst_page = dst_node->page[0];
110 
111 	memcpy(kmap(dst_page) + dst, kmap(src_page) + src, len);
112 	kunmap(src_page);
113 	kunmap(dst_page);
114 	set_page_dirty(dst_page);
115 }
116 
117 void hfs_bnode_move(struct hfs_bnode *node, int dst, int src, int len)
118 {
119 	struct page *page;
120 	void *ptr;
121 
122 	dprint(DBG_BNODE_MOD, "movebytes: %u,%u,%u\n", dst, src, len);
123 	if (!len)
124 		return;
125 	src += node->page_offset;
126 	dst += node->page_offset;
127 	page = node->page[0];
128 	ptr = kmap(page);
129 	memmove(ptr + dst, ptr + src, len);
130 	kunmap(page);
131 	set_page_dirty(page);
132 }
133 
134 void hfs_bnode_dump(struct hfs_bnode *node)
135 {
136 	struct hfs_bnode_desc desc;
137 	__be32 cnid;
138 	int i, off, key_off;
139 
140 	dprint(DBG_BNODE_MOD, "bnode: %d\n", node->this);
141 	hfs_bnode_read(node, &desc, 0, sizeof(desc));
142 	dprint(DBG_BNODE_MOD, "%d, %d, %d, %d, %d\n",
143 		be32_to_cpu(desc.next), be32_to_cpu(desc.prev),
144 		desc.type, desc.height, be16_to_cpu(desc.num_recs));
145 
146 	off = node->tree->node_size - 2;
147 	for (i = be16_to_cpu(desc.num_recs); i >= 0; off -= 2, i--) {
148 		key_off = hfs_bnode_read_u16(node, off);
149 		dprint(DBG_BNODE_MOD, " %d", key_off);
150 		if (i && node->type == HFS_NODE_INDEX) {
151 			int tmp;
152 
153 			if (node->tree->attributes & HFS_TREE_VARIDXKEYS)
154 				tmp = (hfs_bnode_read_u8(node, key_off) | 1) + 1;
155 			else
156 				tmp = node->tree->max_key_len + 1;
157 			dprint(DBG_BNODE_MOD, " (%d,%d", tmp, hfs_bnode_read_u8(node, key_off));
158 			hfs_bnode_read(node, &cnid, key_off + tmp, 4);
159 			dprint(DBG_BNODE_MOD, ",%d)", be32_to_cpu(cnid));
160 		} else if (i && node->type == HFS_NODE_LEAF) {
161 			int tmp;
162 
163 			tmp = hfs_bnode_read_u8(node, key_off);
164 			dprint(DBG_BNODE_MOD, " (%d)", tmp);
165 		}
166 	}
167 	dprint(DBG_BNODE_MOD, "\n");
168 }
169 
170 void hfs_bnode_unlink(struct hfs_bnode *node)
171 {
172 	struct hfs_btree *tree;
173 	struct hfs_bnode *tmp;
174 	__be32 cnid;
175 
176 	tree = node->tree;
177 	if (node->prev) {
178 		tmp = hfs_bnode_find(tree, node->prev);
179 		if (IS_ERR(tmp))
180 			return;
181 		tmp->next = node->next;
182 		cnid = cpu_to_be32(tmp->next);
183 		hfs_bnode_write(tmp, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
184 		hfs_bnode_put(tmp);
185 	} else if (node->type == HFS_NODE_LEAF)
186 		tree->leaf_head = node->next;
187 
188 	if (node->next) {
189 		tmp = hfs_bnode_find(tree, node->next);
190 		if (IS_ERR(tmp))
191 			return;
192 		tmp->prev = node->prev;
193 		cnid = cpu_to_be32(tmp->prev);
194 		hfs_bnode_write(tmp, &cnid, offsetof(struct hfs_bnode_desc, prev), 4);
195 		hfs_bnode_put(tmp);
196 	} else if (node->type == HFS_NODE_LEAF)
197 		tree->leaf_tail = node->prev;
198 
199 	// move down?
200 	if (!node->prev && !node->next) {
201 		printk("hfs_btree_del_level\n");
202 	}
203 	if (!node->parent) {
204 		tree->root = 0;
205 		tree->depth = 0;
206 	}
207 	set_bit(HFS_BNODE_DELETED, &node->flags);
208 }
209 
210 static inline int hfs_bnode_hash(u32 num)
211 {
212 	num = (num >> 16) + num;
213 	num += num >> 8;
214 	return num & (NODE_HASH_SIZE - 1);
215 }
216 
217 struct hfs_bnode *hfs_bnode_findhash(struct hfs_btree *tree, u32 cnid)
218 {
219 	struct hfs_bnode *node;
220 
221 	if (cnid >= tree->node_count) {
222 		printk("HFS: request for non-existent node %d in B*Tree\n", cnid);
223 		return NULL;
224 	}
225 
226 	for (node = tree->node_hash[hfs_bnode_hash(cnid)];
227 	     node; node = node->next_hash) {
228 		if (node->this == cnid) {
229 			return node;
230 		}
231 	}
232 	return NULL;
233 }
234 
235 static struct hfs_bnode *__hfs_bnode_create(struct hfs_btree *tree, u32 cnid)
236 {
237 	struct super_block *sb;
238 	struct hfs_bnode *node, *node2;
239 	struct address_space *mapping;
240 	struct page *page;
241 	int size, block, i, hash;
242 	loff_t off;
243 
244 	if (cnid >= tree->node_count) {
245 		printk("HFS: request for non-existent node %d in B*Tree\n", cnid);
246 		return NULL;
247 	}
248 
249 	sb = tree->inode->i_sb;
250 	size = sizeof(struct hfs_bnode) + tree->pages_per_bnode *
251 		sizeof(struct page *);
252 	node = kmalloc(size, GFP_KERNEL);
253 	if (!node)
254 		return NULL;
255 	memset(node, 0, size);
256 	node->tree = tree;
257 	node->this = cnid;
258 	set_bit(HFS_BNODE_NEW, &node->flags);
259 	atomic_set(&node->refcnt, 1);
260 	dprint(DBG_BNODE_REFS, "new_node(%d:%d): 1\n",
261 	       node->tree->cnid, node->this);
262 	init_waitqueue_head(&node->lock_wq);
263 	spin_lock(&tree->hash_lock);
264 	node2 = hfs_bnode_findhash(tree, cnid);
265 	if (!node2) {
266 		hash = hfs_bnode_hash(cnid);
267 		node->next_hash = tree->node_hash[hash];
268 		tree->node_hash[hash] = node;
269 		tree->node_hash_cnt++;
270 	} else {
271 		spin_unlock(&tree->hash_lock);
272 		kfree(node);
273 		wait_event(node2->lock_wq, !test_bit(HFS_BNODE_NEW, &node2->flags));
274 		return node2;
275 	}
276 	spin_unlock(&tree->hash_lock);
277 
278 	mapping = tree->inode->i_mapping;
279 	off = (loff_t)cnid * tree->node_size;
280 	block = off >> PAGE_CACHE_SHIFT;
281 	node->page_offset = off & ~PAGE_CACHE_MASK;
282 	for (i = 0; i < tree->pages_per_bnode; i++) {
283 		page = read_cache_page(mapping, block++, (filler_t *)mapping->a_ops->readpage, NULL);
284 		if (IS_ERR(page))
285 			goto fail;
286 		if (PageError(page)) {
287 			page_cache_release(page);
288 			goto fail;
289 		}
290 		page_cache_release(page);
291 		node->page[i] = page;
292 	}
293 
294 	return node;
295 fail:
296 	set_bit(HFS_BNODE_ERROR, &node->flags);
297 	return node;
298 }
299 
300 void hfs_bnode_unhash(struct hfs_bnode *node)
301 {
302 	struct hfs_bnode **p;
303 
304 	dprint(DBG_BNODE_REFS, "remove_node(%d:%d): %d\n",
305 		node->tree->cnid, node->this, atomic_read(&node->refcnt));
306 	for (p = &node->tree->node_hash[hfs_bnode_hash(node->this)];
307 	     *p && *p != node; p = &(*p)->next_hash)
308 		;
309 	if (!*p)
310 		BUG();
311 	*p = node->next_hash;
312 	node->tree->node_hash_cnt--;
313 }
314 
315 /* Load a particular node out of a tree */
316 struct hfs_bnode *hfs_bnode_find(struct hfs_btree *tree, u32 num)
317 {
318 	struct hfs_bnode *node;
319 	struct hfs_bnode_desc *desc;
320 	int i, rec_off, off, next_off;
321 	int entry_size, key_size;
322 
323 	spin_lock(&tree->hash_lock);
324 	node = hfs_bnode_findhash(tree, num);
325 	if (node) {
326 		hfs_bnode_get(node);
327 		spin_unlock(&tree->hash_lock);
328 		wait_event(node->lock_wq, !test_bit(HFS_BNODE_NEW, &node->flags));
329 		if (test_bit(HFS_BNODE_ERROR, &node->flags))
330 			goto node_error;
331 		return node;
332 	}
333 	spin_unlock(&tree->hash_lock);
334 	node = __hfs_bnode_create(tree, num);
335 	if (!node)
336 		return ERR_PTR(-ENOMEM);
337 	if (test_bit(HFS_BNODE_ERROR, &node->flags))
338 		goto node_error;
339 	if (!test_bit(HFS_BNODE_NEW, &node->flags))
340 		return node;
341 
342 	desc = (struct hfs_bnode_desc *)(kmap(node->page[0]) + node->page_offset);
343 	node->prev = be32_to_cpu(desc->prev);
344 	node->next = be32_to_cpu(desc->next);
345 	node->num_recs = be16_to_cpu(desc->num_recs);
346 	node->type = desc->type;
347 	node->height = desc->height;
348 	kunmap(node->page[0]);
349 
350 	switch (node->type) {
351 	case HFS_NODE_HEADER:
352 	case HFS_NODE_MAP:
353 		if (node->height != 0)
354 			goto node_error;
355 		break;
356 	case HFS_NODE_LEAF:
357 		if (node->height != 1)
358 			goto node_error;
359 		break;
360 	case HFS_NODE_INDEX:
361 		if (node->height <= 1 || node->height > tree->depth)
362 			goto node_error;
363 		break;
364 	default:
365 		goto node_error;
366 	}
367 
368 	rec_off = tree->node_size - 2;
369 	off = hfs_bnode_read_u16(node, rec_off);
370 	if (off != sizeof(struct hfs_bnode_desc))
371 		goto node_error;
372 	for (i = 1; i <= node->num_recs; off = next_off, i++) {
373 		rec_off -= 2;
374 		next_off = hfs_bnode_read_u16(node, rec_off);
375 		if (next_off <= off ||
376 		    next_off > tree->node_size ||
377 		    next_off & 1)
378 			goto node_error;
379 		entry_size = next_off - off;
380 		if (node->type != HFS_NODE_INDEX &&
381 		    node->type != HFS_NODE_LEAF)
382 			continue;
383 		key_size = hfs_bnode_read_u8(node, off) + 1;
384 		if (key_size >= entry_size /*|| key_size & 1*/)
385 			goto node_error;
386 	}
387 	clear_bit(HFS_BNODE_NEW, &node->flags);
388 	wake_up(&node->lock_wq);
389 	return node;
390 
391 node_error:
392 	set_bit(HFS_BNODE_ERROR, &node->flags);
393 	clear_bit(HFS_BNODE_NEW, &node->flags);
394 	wake_up(&node->lock_wq);
395 	hfs_bnode_put(node);
396 	return ERR_PTR(-EIO);
397 }
398 
399 void hfs_bnode_free(struct hfs_bnode *node)
400 {
401 	//int i;
402 
403 	//for (i = 0; i < node->tree->pages_per_bnode; i++)
404 	//	if (node->page[i])
405 	//		page_cache_release(node->page[i]);
406 	kfree(node);
407 }
408 
409 struct hfs_bnode *hfs_bnode_create(struct hfs_btree *tree, u32 num)
410 {
411 	struct hfs_bnode *node;
412 	struct page **pagep;
413 	int i;
414 
415 	spin_lock(&tree->hash_lock);
416 	node = hfs_bnode_findhash(tree, num);
417 	spin_unlock(&tree->hash_lock);
418 	if (node)
419 		BUG();
420 	node = __hfs_bnode_create(tree, num);
421 	if (!node)
422 		return ERR_PTR(-ENOMEM);
423 	if (test_bit(HFS_BNODE_ERROR, &node->flags)) {
424 		hfs_bnode_put(node);
425 		return ERR_PTR(-EIO);
426 	}
427 
428 	pagep = node->page;
429 	memset(kmap(*pagep) + node->page_offset, 0,
430 	       min((int)PAGE_CACHE_SIZE, (int)tree->node_size));
431 	set_page_dirty(*pagep);
432 	kunmap(*pagep);
433 	for (i = 1; i < tree->pages_per_bnode; i++) {
434 		memset(kmap(*++pagep), 0, PAGE_CACHE_SIZE);
435 		set_page_dirty(*pagep);
436 		kunmap(*pagep);
437 	}
438 	clear_bit(HFS_BNODE_NEW, &node->flags);
439 	wake_up(&node->lock_wq);
440 
441 	return node;
442 }
443 
444 void hfs_bnode_get(struct hfs_bnode *node)
445 {
446 	if (node) {
447 		atomic_inc(&node->refcnt);
448 		dprint(DBG_BNODE_REFS, "get_node(%d:%d): %d\n",
449 		       node->tree->cnid, node->this, atomic_read(&node->refcnt));
450 	}
451 }
452 
453 /* Dispose of resources used by a node */
454 void hfs_bnode_put(struct hfs_bnode *node)
455 {
456 	if (node) {
457 		struct hfs_btree *tree = node->tree;
458 		int i;
459 
460 		dprint(DBG_BNODE_REFS, "put_node(%d:%d): %d\n",
461 		       node->tree->cnid, node->this, atomic_read(&node->refcnt));
462 		if (!atomic_read(&node->refcnt))
463 			BUG();
464 		if (!atomic_dec_and_lock(&node->refcnt, &tree->hash_lock))
465 			return;
466 		for (i = 0; i < tree->pages_per_bnode; i++) {
467 			if (!node->page[i])
468 				continue;
469 			mark_page_accessed(node->page[i]);
470 		}
471 
472 		if (test_bit(HFS_BNODE_DELETED, &node->flags)) {
473 			hfs_bnode_unhash(node);
474 			spin_unlock(&tree->hash_lock);
475 			hfs_bmap_free(node);
476 			hfs_bnode_free(node);
477 			return;
478 		}
479 		spin_unlock(&tree->hash_lock);
480 	}
481 }
482