xref: /openbmc/linux/fs/hfs/bnode.c (revision 0f4630f3) 
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/slab.h>
13 #include <linux/swap.h>
14 
15 #include "btree.h"
16 
17 void hfs_bnode_read(struct hfs_bnode *node, void *buf,
18 		int off, int len)
19 {
20 	struct page *page;
21 
22 	off += node->page_offset;
23 	page = node->page[0];
24 
25 	memcpy(buf, kmap(page) + off, len);
26 	kunmap(page);
27 }
28 
29 u16 hfs_bnode_read_u16(struct hfs_bnode *node, int off)
30 {
31 	__be16 data;
32 	// optimize later...
33 	hfs_bnode_read(node, &data, off, 2);
34 	return be16_to_cpu(data);
35 }
36 
37 u8 hfs_bnode_read_u8(struct hfs_bnode *node, int off)
38 {
39 	u8 data;
40 	// optimize later...
41 	hfs_bnode_read(node, &data, off, 1);
42 	return data;
43 }
44 
45 void hfs_bnode_read_key(struct hfs_bnode *node, void *key, int off)
46 {
47 	struct hfs_btree *tree;
48 	int key_len;
49 
50 	tree = node->tree;
51 	if (node->type == HFS_NODE_LEAF ||
52 	    tree->attributes & HFS_TREE_VARIDXKEYS)
53 		key_len = hfs_bnode_read_u8(node, off) + 1;
54 	else
55 		key_len = tree->max_key_len + 1;
56 
57 	hfs_bnode_read(node, key, off, key_len);
58 }
59 
60 void hfs_bnode_write(struct hfs_bnode *node, void *buf, int off, int len)
61 {
62 	struct page *page;
63 
64 	off += node->page_offset;
65 	page = node->page[0];
66 
67 	memcpy(kmap(page) + off, buf, len);
68 	kunmap(page);
69 	set_page_dirty(page);
70 }
71 
72 void hfs_bnode_write_u16(struct hfs_bnode *node, int off, u16 data)
73 {
74 	__be16 v = cpu_to_be16(data);
75 	// optimize later...
76 	hfs_bnode_write(node, &v, off, 2);
77 }
78 
79 void hfs_bnode_write_u8(struct hfs_bnode *node, int off, u8 data)
80 {
81 	// optimize later...
82 	hfs_bnode_write(node, &data, off, 1);
83 }
84 
85 void hfs_bnode_clear(struct hfs_bnode *node, int off, int len)
86 {
87 	struct page *page;
88 
89 	off += node->page_offset;
90 	page = node->page[0];
91 
92 	memset(kmap(page) + off, 0, len);
93 	kunmap(page);
94 	set_page_dirty(page);
95 }
96 
97 void hfs_bnode_copy(struct hfs_bnode *dst_node, int dst,
98 		struct hfs_bnode *src_node, int src, int len)
99 {
100 	struct hfs_btree *tree;
101 	struct page *src_page, *dst_page;
102 
103 	hfs_dbg(BNODE_MOD, "copybytes: %u,%u,%u\n", dst, src, len);
104 	if (!len)
105 		return;
106 	tree = src_node->tree;
107 	src += src_node->page_offset;
108 	dst += dst_node->page_offset;
109 	src_page = src_node->page[0];
110 	dst_page = dst_node->page[0];
111 
112 	memcpy(kmap(dst_page) + dst, kmap(src_page) + src, len);
113 	kunmap(src_page);
114 	kunmap(dst_page);
115 	set_page_dirty(dst_page);
116 }
117 
118 void hfs_bnode_move(struct hfs_bnode *node, int dst, int src, int len)
119 {
120 	struct page *page;
121 	void *ptr;
122 
123 	hfs_dbg(BNODE_MOD, "movebytes: %u,%u,%u\n", dst, src, len);
124 	if (!len)
125 		return;
126 	src += node->page_offset;
127 	dst += node->page_offset;
128 	page = node->page[0];
129 	ptr = kmap(page);
130 	memmove(ptr + dst, ptr + src, len);
131 	kunmap(page);
132 	set_page_dirty(page);
133 }
134 
135 void hfs_bnode_dump(struct hfs_bnode *node)
136 {
137 	struct hfs_bnode_desc desc;
138 	__be32 cnid;
139 	int i, off, key_off;
140 
141 	hfs_dbg(BNODE_MOD, "bnode: %d\n", node->this);
142 	hfs_bnode_read(node, &desc, 0, sizeof(desc));
143 	hfs_dbg(BNODE_MOD, "%d, %d, %d, %d, %d\n",
144 		be32_to_cpu(desc.next), be32_to_cpu(desc.prev),
145 		desc.type, desc.height, be16_to_cpu(desc.num_recs));
146 
147 	off = node->tree->node_size - 2;
148 	for (i = be16_to_cpu(desc.num_recs); i >= 0; off -= 2, i--) {
149 		key_off = hfs_bnode_read_u16(node, off);
150 		hfs_dbg_cont(BNODE_MOD, " %d", key_off);
151 		if (i && node->type == HFS_NODE_INDEX) {
152 			int tmp;
153 
154 			if (node->tree->attributes & HFS_TREE_VARIDXKEYS)
155 				tmp = (hfs_bnode_read_u8(node, key_off) | 1) + 1;
156 			else
157 				tmp = node->tree->max_key_len + 1;
158 			hfs_dbg_cont(BNODE_MOD, " (%d,%d",
159 				     tmp, hfs_bnode_read_u8(node, key_off));
160 			hfs_bnode_read(node, &cnid, key_off + tmp, 4);
161 			hfs_dbg_cont(BNODE_MOD, ",%d)", be32_to_cpu(cnid));
162 		} else if (i && node->type == HFS_NODE_LEAF) {
163 			int tmp;
164 
165 			tmp = hfs_bnode_read_u8(node, key_off);
166 			hfs_dbg_cont(BNODE_MOD, " (%d)", tmp);
167 		}
168 	}
169 	hfs_dbg_cont(BNODE_MOD, "\n");
170 }
171 
172 void hfs_bnode_unlink(struct hfs_bnode *node)
173 {
174 	struct hfs_btree *tree;
175 	struct hfs_bnode *tmp;
176 	__be32 cnid;
177 
178 	tree = node->tree;
179 	if (node->prev) {
180 		tmp = hfs_bnode_find(tree, node->prev);
181 		if (IS_ERR(tmp))
182 			return;
183 		tmp->next = node->next;
184 		cnid = cpu_to_be32(tmp->next);
185 		hfs_bnode_write(tmp, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
186 		hfs_bnode_put(tmp);
187 	} else if (node->type == HFS_NODE_LEAF)
188 		tree->leaf_head = node->next;
189 
190 	if (node->next) {
191 		tmp = hfs_bnode_find(tree, node->next);
192 		if (IS_ERR(tmp))
193 			return;
194 		tmp->prev = node->prev;
195 		cnid = cpu_to_be32(tmp->prev);
196 		hfs_bnode_write(tmp, &cnid, offsetof(struct hfs_bnode_desc, prev), 4);
197 		hfs_bnode_put(tmp);
198 	} else if (node->type == HFS_NODE_LEAF)
199 		tree->leaf_tail = node->prev;
200 
201 	// move down?
202 	if (!node->prev && !node->next) {
203 		printk(KERN_DEBUG "hfs_btree_del_level\n");
204 	}
205 	if (!node->parent) {
206 		tree->root = 0;
207 		tree->depth = 0;
208 	}
209 	set_bit(HFS_BNODE_DELETED, &node->flags);
210 }
211 
212 static inline int hfs_bnode_hash(u32 num)
213 {
214 	num = (num >> 16) + num;
215 	num += num >> 8;
216 	return num & (NODE_HASH_SIZE - 1);
217 }
218 
219 struct hfs_bnode *hfs_bnode_findhash(struct hfs_btree *tree, u32 cnid)
220 {
221 	struct hfs_bnode *node;
222 
223 	if (cnid >= tree->node_count) {
224 		pr_err("request for non-existent node %d in B*Tree\n", cnid);
225 		return NULL;
226 	}
227 
228 	for (node = tree->node_hash[hfs_bnode_hash(cnid)];
229 	     node; node = node->next_hash) {
230 		if (node->this == cnid) {
231 			return node;
232 		}
233 	}
234 	return NULL;
235 }
236 
237 static struct hfs_bnode *__hfs_bnode_create(struct hfs_btree *tree, u32 cnid)
238 {
239 	struct super_block *sb;
240 	struct hfs_bnode *node, *node2;
241 	struct address_space *mapping;
242 	struct page *page;
243 	int size, block, i, hash;
244 	loff_t off;
245 
246 	if (cnid >= tree->node_count) {
247 		pr_err("request for non-existent node %d in B*Tree\n", cnid);
248 		return NULL;
249 	}
250 
251 	sb = tree->inode->i_sb;
252 	size = sizeof(struct hfs_bnode) + tree->pages_per_bnode *
253 		sizeof(struct page *);
254 	node = kzalloc(size, GFP_KERNEL);
255 	if (!node)
256 		return NULL;
257 	node->tree = tree;
258 	node->this = cnid;
259 	set_bit(HFS_BNODE_NEW, &node->flags);
260 	atomic_set(&node->refcnt, 1);
261 	hfs_dbg(BNODE_REFS, "new_node(%d:%d): 1\n",
262 		node->tree->cnid, node->this);
263 	init_waitqueue_head(&node->lock_wq);
264 	spin_lock(&tree->hash_lock);
265 	node2 = hfs_bnode_findhash(tree, cnid);
266 	if (!node2) {
267 		hash = hfs_bnode_hash(cnid);
268 		node->next_hash = tree->node_hash[hash];
269 		tree->node_hash[hash] = node;
270 		tree->node_hash_cnt++;
271 	} else {
272 		spin_unlock(&tree->hash_lock);
273 		kfree(node);
274 		wait_event(node2->lock_wq, !test_bit(HFS_BNODE_NEW, &node2->flags));
275 		return node2;
276 	}
277 	spin_unlock(&tree->hash_lock);
278 
279 	mapping = tree->inode->i_mapping;
280 	off = (loff_t)cnid * tree->node_size;
281 	block = off >> PAGE_CACHE_SHIFT;
282 	node->page_offset = off & ~PAGE_CACHE_MASK;
283 	for (i = 0; i < tree->pages_per_bnode; i++) {
284 		page = read_mapping_page(mapping, block++, NULL);
285 		if (IS_ERR(page))
286 			goto fail;
287 		if (PageError(page)) {
288 			page_cache_release(page);
289 			goto fail;
290 		}
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 	hfs_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 	BUG_ON(!*p);
310 	*p = node->next_hash;
311 	node->tree->node_hash_cnt--;
312 }
313 
314 /* Load a particular node out of a tree */
315 struct hfs_bnode *hfs_bnode_find(struct hfs_btree *tree, u32 num)
316 {
317 	struct hfs_bnode *node;
318 	struct hfs_bnode_desc *desc;
319 	int i, rec_off, off, next_off;
320 	int entry_size, key_size;
321 
322 	spin_lock(&tree->hash_lock);
323 	node = hfs_bnode_findhash(tree, num);
324 	if (node) {
325 		hfs_bnode_get(node);
326 		spin_unlock(&tree->hash_lock);
327 		wait_event(node->lock_wq, !test_bit(HFS_BNODE_NEW, &node->flags));
328 		if (test_bit(HFS_BNODE_ERROR, &node->flags))
329 			goto node_error;
330 		return node;
331 	}
332 	spin_unlock(&tree->hash_lock);
333 	node = __hfs_bnode_create(tree, num);
334 	if (!node)
335 		return ERR_PTR(-ENOMEM);
336 	if (test_bit(HFS_BNODE_ERROR, &node->flags))
337 		goto node_error;
338 	if (!test_bit(HFS_BNODE_NEW, &node->flags))
339 		return node;
340 
341 	desc = (struct hfs_bnode_desc *)(kmap(node->page[0]) + node->page_offset);
342 	node->prev = be32_to_cpu(desc->prev);
343 	node->next = be32_to_cpu(desc->next);
344 	node->num_recs = be16_to_cpu(desc->num_recs);
345 	node->type = desc->type;
346 	node->height = desc->height;
347 	kunmap(node->page[0]);
348 
349 	switch (node->type) {
350 	case HFS_NODE_HEADER:
351 	case HFS_NODE_MAP:
352 		if (node->height != 0)
353 			goto node_error;
354 		break;
355 	case HFS_NODE_LEAF:
356 		if (node->height != 1)
357 			goto node_error;
358 		break;
359 	case HFS_NODE_INDEX:
360 		if (node->height <= 1 || node->height > tree->depth)
361 			goto node_error;
362 		break;
363 	default:
364 		goto node_error;
365 	}
366 
367 	rec_off = tree->node_size - 2;
368 	off = hfs_bnode_read_u16(node, rec_off);
369 	if (off != sizeof(struct hfs_bnode_desc))
370 		goto node_error;
371 	for (i = 1; i <= node->num_recs; off = next_off, i++) {
372 		rec_off -= 2;
373 		next_off = hfs_bnode_read_u16(node, rec_off);
374 		if (next_off <= off ||
375 		    next_off > tree->node_size ||
376 		    next_off & 1)
377 			goto node_error;
378 		entry_size = next_off - off;
379 		if (node->type != HFS_NODE_INDEX &&
380 		    node->type != HFS_NODE_LEAF)
381 			continue;
382 		key_size = hfs_bnode_read_u8(node, off) + 1;
383 		if (key_size >= entry_size /*|| key_size & 1*/)
384 			goto node_error;
385 	}
386 	clear_bit(HFS_BNODE_NEW, &node->flags);
387 	wake_up(&node->lock_wq);
388 	return node;
389 
390 node_error:
391 	set_bit(HFS_BNODE_ERROR, &node->flags);
392 	clear_bit(HFS_BNODE_NEW, &node->flags);
393 	wake_up(&node->lock_wq);
394 	hfs_bnode_put(node);
395 	return ERR_PTR(-EIO);
396 }
397 
398 void hfs_bnode_free(struct hfs_bnode *node)
399 {
400 	int i;
401 
402 	for (i = 0; i < node->tree->pages_per_bnode; i++)
403 		if (node->page[i])
404 			page_cache_release(node->page[i]);
405 	kfree(node);
406 }
407 
408 struct hfs_bnode *hfs_bnode_create(struct hfs_btree *tree, u32 num)
409 {
410 	struct hfs_bnode *node;
411 	struct page **pagep;
412 	int i;
413 
414 	spin_lock(&tree->hash_lock);
415 	node = hfs_bnode_findhash(tree, num);
416 	spin_unlock(&tree->hash_lock);
417 	if (node) {
418 		pr_crit("new node %u already hashed?\n", num);
419 		WARN_ON(1);
420 		return node;
421 	}
422 	node = __hfs_bnode_create(tree, num);
423 	if (!node)
424 		return ERR_PTR(-ENOMEM);
425 	if (test_bit(HFS_BNODE_ERROR, &node->flags)) {
426 		hfs_bnode_put(node);
427 		return ERR_PTR(-EIO);
428 	}
429 
430 	pagep = node->page;
431 	memset(kmap(*pagep) + node->page_offset, 0,
432 	       min((int)PAGE_CACHE_SIZE, (int)tree->node_size));
433 	set_page_dirty(*pagep);
434 	kunmap(*pagep);
435 	for (i = 1; i < tree->pages_per_bnode; i++) {
436 		memset(kmap(*++pagep), 0, PAGE_CACHE_SIZE);
437 		set_page_dirty(*pagep);
438 		kunmap(*pagep);
439 	}
440 	clear_bit(HFS_BNODE_NEW, &node->flags);
441 	wake_up(&node->lock_wq);
442 
443 	return node;
444 }
445 
446 void hfs_bnode_get(struct hfs_bnode *node)
447 {
448 	if (node) {
449 		atomic_inc(&node->refcnt);
450 		hfs_dbg(BNODE_REFS, "get_node(%d:%d): %d\n",
451 			node->tree->cnid, node->this,
452 			atomic_read(&node->refcnt));
453 	}
454 }
455 
456 /* Dispose of resources used by a node */
457 void hfs_bnode_put(struct hfs_bnode *node)
458 {
459 	if (node) {
460 		struct hfs_btree *tree = node->tree;
461 		int i;
462 
463 		hfs_dbg(BNODE_REFS, "put_node(%d:%d): %d\n",
464 			node->tree->cnid, node->this,
465 			atomic_read(&node->refcnt));
466 		BUG_ON(!atomic_read(&node->refcnt));
467 		if (!atomic_dec_and_lock(&node->refcnt, &tree->hash_lock))
468 			return;
469 		for (i = 0; i < tree->pages_per_bnode; i++) {
470 			if (!node->page[i])
471 				continue;
472 			mark_page_accessed(node->page[i]);
473 		}
474 
475 		if (test_bit(HFS_BNODE_DELETED, &node->flags)) {
476 			hfs_bnode_unhash(node);
477 			spin_unlock(&tree->hash_lock);
478 			hfs_bmap_free(node);
479 			hfs_bnode_free(node);
480 			return;
481 		}
482 		spin_unlock(&tree->hash_lock);
483 	}
484 }
485