xref: /openbmc/linux/fs/hfs/bnode.c (revision e6e8c82b) 
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  linux/fs/hfs/bnode.c
4  *
5  * Copyright (C) 2001
6  * Brad Boyer (flar@allandria.com)
7  * (C) 2003 Ardis Technologies <roman@ardistech.com>
8  *
9  * Handle basic btree node operations
10  */
11 
12 #include <linux/pagemap.h>
13 #include <linux/slab.h>
14 #include <linux/swap.h>
15 
16 #include "btree.h"
17 
18 void hfs_bnode_read(struct hfs_bnode *node, void *buf,
19 		int off, int len)
20 {
21 	struct page *page;
22 
23 	off += node->page_offset;
24 	page = node->page[0];
25 
26 	memcpy(buf, kmap(page) + off, len);
27 	kunmap(page);
28 }
29 
30 u16 hfs_bnode_read_u16(struct hfs_bnode *node, int off)
31 {
32 	__be16 data;
33 	// optimize later...
34 	hfs_bnode_read(node, &data, off, 2);
35 	return be16_to_cpu(data);
36 }
37 
38 u8 hfs_bnode_read_u8(struct hfs_bnode *node, int off)
39 {
40 	u8 data;
41 	// optimize later...
42 	hfs_bnode_read(node, &data, off, 1);
43 	return data;
44 }
45 
46 void hfs_bnode_read_key(struct hfs_bnode *node, void *key, int off)
47 {
48 	struct hfs_btree *tree;
49 	int key_len;
50 
51 	tree = node->tree;
52 	if (node->type == HFS_NODE_LEAF ||
53 	    tree->attributes & HFS_TREE_VARIDXKEYS)
54 		key_len = hfs_bnode_read_u8(node, off) + 1;
55 	else
56 		key_len = tree->max_key_len + 1;
57 
58 	hfs_bnode_read(node, key, off, key_len);
59 }
60 
61 void hfs_bnode_write(struct hfs_bnode *node, void *buf, int off, int len)
62 {
63 	struct page *page;
64 
65 	off += node->page_offset;
66 	page = node->page[0];
67 
68 	memcpy(kmap(page) + off, buf, len);
69 	kunmap(page);
70 	set_page_dirty(page);
71 }
72 
73 void hfs_bnode_write_u16(struct hfs_bnode *node, int off, u16 data)
74 {
75 	__be16 v = cpu_to_be16(data);
76 	// optimize later...
77 	hfs_bnode_write(node, &v, off, 2);
78 }
79 
80 void hfs_bnode_write_u8(struct hfs_bnode *node, int off, u8 data)
81 {
82 	// optimize later...
83 	hfs_bnode_write(node, &data, off, 1);
84 }
85 
86 void hfs_bnode_clear(struct hfs_bnode *node, int off, int len)
87 {
88 	struct page *page;
89 
90 	off += node->page_offset;
91 	page = node->page[0];
92 
93 	memset(kmap(page) + off, 0, len);
94 	kunmap(page);
95 	set_page_dirty(page);
96 }
97 
98 void hfs_bnode_copy(struct hfs_bnode *dst_node, int dst,
99 		struct hfs_bnode *src_node, int src, int len)
100 {
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 	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 	hfs_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 	hfs_dbg(BNODE_MOD, "bnode: %d\n", node->this);
141 	hfs_bnode_read(node, &desc, 0, sizeof(desc));
142 	hfs_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 		hfs_dbg_cont(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 			hfs_dbg_cont(BNODE_MOD, " (%d,%d",
158 				     tmp, hfs_bnode_read_u8(node, key_off));
159 			hfs_bnode_read(node, &cnid, key_off + tmp, 4);
160 			hfs_dbg_cont(BNODE_MOD, ",%d)", be32_to_cpu(cnid));
161 		} else if (i && node->type == HFS_NODE_LEAF) {
162 			int tmp;
163 
164 			tmp = hfs_bnode_read_u8(node, key_off);
165 			hfs_dbg_cont(BNODE_MOD, " (%d)", tmp);
166 		}
167 	}
168 	hfs_dbg_cont(BNODE_MOD, "\n");
169 }
170 
171 void hfs_bnode_unlink(struct hfs_bnode *node)
172 {
173 	struct hfs_btree *tree;
174 	struct hfs_bnode *tmp;
175 	__be32 cnid;
176 
177 	tree = node->tree;
178 	if (node->prev) {
179 		tmp = hfs_bnode_find(tree, node->prev);
180 		if (IS_ERR(tmp))
181 			return;
182 		tmp->next = node->next;
183 		cnid = cpu_to_be32(tmp->next);
184 		hfs_bnode_write(tmp, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
185 		hfs_bnode_put(tmp);
186 	} else if (node->type == HFS_NODE_LEAF)
187 		tree->leaf_head = node->next;
188 
189 	if (node->next) {
190 		tmp = hfs_bnode_find(tree, node->next);
191 		if (IS_ERR(tmp))
192 			return;
193 		tmp->prev = node->prev;
194 		cnid = cpu_to_be32(tmp->prev);
195 		hfs_bnode_write(tmp, &cnid, offsetof(struct hfs_bnode_desc, prev), 4);
196 		hfs_bnode_put(tmp);
197 	} else if (node->type == HFS_NODE_LEAF)
198 		tree->leaf_tail = node->prev;
199 
200 	// move down?
201 	if (!node->prev && !node->next) {
202 		printk(KERN_DEBUG "hfs_btree_del_level\n");
203 	}
204 	if (!node->parent) {
205 		tree->root = 0;
206 		tree->depth = 0;
207 	}
208 	set_bit(HFS_BNODE_DELETED, &node->flags);
209 }
210 
211 static inline int hfs_bnode_hash(u32 num)
212 {
213 	num = (num >> 16) + num;
214 	num += num >> 8;
215 	return num & (NODE_HASH_SIZE - 1);
216 }
217 
218 struct hfs_bnode *hfs_bnode_findhash(struct hfs_btree *tree, u32 cnid)
219 {
220 	struct hfs_bnode *node;
221 
222 	if (cnid >= tree->node_count) {
223 		pr_err("request for non-existent node %d in B*Tree\n", cnid);
224 		return NULL;
225 	}
226 
227 	for (node = tree->node_hash[hfs_bnode_hash(cnid)];
228 	     node; node = node->next_hash) {
229 		if (node->this == cnid) {
230 			return node;
231 		}
232 	}
233 	return NULL;
234 }
235 
236 static struct hfs_bnode *__hfs_bnode_create(struct hfs_btree *tree, u32 cnid)
237 {
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 		pr_err("request for non-existent node %d in B*Tree\n", cnid);
246 		return NULL;
247 	}
248 
249 	size = sizeof(struct hfs_bnode) + tree->pages_per_bnode *
250 		sizeof(struct page *);
251 	node = kzalloc(size, GFP_KERNEL);
252 	if (!node)
253 		return NULL;
254 	node->tree = tree;
255 	node->this = cnid;
256 	set_bit(HFS_BNODE_NEW, &node->flags);
257 	atomic_set(&node->refcnt, 1);
258 	hfs_dbg(BNODE_REFS, "new_node(%d:%d): 1\n",
259 		node->tree->cnid, node->this);
260 	init_waitqueue_head(&node->lock_wq);
261 	spin_lock(&tree->hash_lock);
262 	node2 = hfs_bnode_findhash(tree, cnid);
263 	if (!node2) {
264 		hash = hfs_bnode_hash(cnid);
265 		node->next_hash = tree->node_hash[hash];
266 		tree->node_hash[hash] = node;
267 		tree->node_hash_cnt++;
268 	} else {
269 		spin_unlock(&tree->hash_lock);
270 		kfree(node);
271 		wait_event(node2->lock_wq, !test_bit(HFS_BNODE_NEW, &node2->flags));
272 		return node2;
273 	}
274 	spin_unlock(&tree->hash_lock);
275 
276 	mapping = tree->inode->i_mapping;
277 	off = (loff_t)cnid * tree->node_size;
278 	block = off >> PAGE_SHIFT;
279 	node->page_offset = off & ~PAGE_MASK;
280 	for (i = 0; i < tree->pages_per_bnode; i++) {
281 		page = read_mapping_page(mapping, block++, NULL);
282 		if (IS_ERR(page))
283 			goto fail;
284 		if (PageError(page)) {
285 			put_page(page);
286 			goto fail;
287 		}
288 		node->page[i] = page;
289 	}
290 
291 	return node;
292 fail:
293 	set_bit(HFS_BNODE_ERROR, &node->flags);
294 	return node;
295 }
296 
297 void hfs_bnode_unhash(struct hfs_bnode *node)
298 {
299 	struct hfs_bnode **p;
300 
301 	hfs_dbg(BNODE_REFS, "remove_node(%d:%d): %d\n",
302 		node->tree->cnid, node->this, atomic_read(&node->refcnt));
303 	for (p = &node->tree->node_hash[hfs_bnode_hash(node->this)];
304 	     *p && *p != node; p = &(*p)->next_hash)
305 		;
306 	BUG_ON(!*p);
307 	*p = node->next_hash;
308 	node->tree->node_hash_cnt--;
309 }
310 
311 /* Load a particular node out of a tree */
312 struct hfs_bnode *hfs_bnode_find(struct hfs_btree *tree, u32 num)
313 {
314 	struct hfs_bnode *node;
315 	struct hfs_bnode_desc *desc;
316 	int i, rec_off, off, next_off;
317 	int entry_size, key_size;
318 
319 	spin_lock(&tree->hash_lock);
320 	node = hfs_bnode_findhash(tree, num);
321 	if (node) {
322 		hfs_bnode_get(node);
323 		spin_unlock(&tree->hash_lock);
324 		wait_event(node->lock_wq, !test_bit(HFS_BNODE_NEW, &node->flags));
325 		if (test_bit(HFS_BNODE_ERROR, &node->flags))
326 			goto node_error;
327 		return node;
328 	}
329 	spin_unlock(&tree->hash_lock);
330 	node = __hfs_bnode_create(tree, num);
331 	if (!node)
332 		return ERR_PTR(-ENOMEM);
333 	if (test_bit(HFS_BNODE_ERROR, &node->flags))
334 		goto node_error;
335 	if (!test_bit(HFS_BNODE_NEW, &node->flags))
336 		return node;
337 
338 	desc = (struct hfs_bnode_desc *)(kmap(node->page[0]) + node->page_offset);
339 	node->prev = be32_to_cpu(desc->prev);
340 	node->next = be32_to_cpu(desc->next);
341 	node->num_recs = be16_to_cpu(desc->num_recs);
342 	node->type = desc->type;
343 	node->height = desc->height;
344 	kunmap(node->page[0]);
345 
346 	switch (node->type) {
347 	case HFS_NODE_HEADER:
348 	case HFS_NODE_MAP:
349 		if (node->height != 0)
350 			goto node_error;
351 		break;
352 	case HFS_NODE_LEAF:
353 		if (node->height != 1)
354 			goto node_error;
355 		break;
356 	case HFS_NODE_INDEX:
357 		if (node->height <= 1 || node->height > tree->depth)
358 			goto node_error;
359 		break;
360 	default:
361 		goto node_error;
362 	}
363 
364 	rec_off = tree->node_size - 2;
365 	off = hfs_bnode_read_u16(node, rec_off);
366 	if (off != sizeof(struct hfs_bnode_desc))
367 		goto node_error;
368 	for (i = 1; i <= node->num_recs; off = next_off, i++) {
369 		rec_off -= 2;
370 		next_off = hfs_bnode_read_u16(node, rec_off);
371 		if (next_off <= off ||
372 		    next_off > tree->node_size ||
373 		    next_off & 1)
374 			goto node_error;
375 		entry_size = next_off - off;
376 		if (node->type != HFS_NODE_INDEX &&
377 		    node->type != HFS_NODE_LEAF)
378 			continue;
379 		key_size = hfs_bnode_read_u8(node, off) + 1;
380 		if (key_size >= entry_size /*|| key_size & 1*/)
381 			goto node_error;
382 	}
383 	clear_bit(HFS_BNODE_NEW, &node->flags);
384 	wake_up(&node->lock_wq);
385 	return node;
386 
387 node_error:
388 	set_bit(HFS_BNODE_ERROR, &node->flags);
389 	clear_bit(HFS_BNODE_NEW, &node->flags);
390 	wake_up(&node->lock_wq);
391 	hfs_bnode_put(node);
392 	return ERR_PTR(-EIO);
393 }
394 
395 void hfs_bnode_free(struct hfs_bnode *node)
396 {
397 	int i;
398 
399 	for (i = 0; i < node->tree->pages_per_bnode; i++)
400 		if (node->page[i])
401 			put_page(node->page[i]);
402 	kfree(node);
403 }
404 
405 struct hfs_bnode *hfs_bnode_create(struct hfs_btree *tree, u32 num)
406 {
407 	struct hfs_bnode *node;
408 	struct page **pagep;
409 	int i;
410 
411 	spin_lock(&tree->hash_lock);
412 	node = hfs_bnode_findhash(tree, num);
413 	spin_unlock(&tree->hash_lock);
414 	if (node) {
415 		pr_crit("new node %u already hashed?\n", num);
416 		WARN_ON(1);
417 		return node;
418 	}
419 	node = __hfs_bnode_create(tree, num);
420 	if (!node)
421 		return ERR_PTR(-ENOMEM);
422 	if (test_bit(HFS_BNODE_ERROR, &node->flags)) {
423 		hfs_bnode_put(node);
424 		return ERR_PTR(-EIO);
425 	}
426 
427 	pagep = node->page;
428 	memset(kmap(*pagep) + node->page_offset, 0,
429 	       min((int)PAGE_SIZE, (int)tree->node_size));
430 	set_page_dirty(*pagep);
431 	kunmap(*pagep);
432 	for (i = 1; i < tree->pages_per_bnode; i++) {
433 		memset(kmap(*++pagep), 0, PAGE_SIZE);
434 		set_page_dirty(*pagep);
435 		kunmap(*pagep);
436 	}
437 	clear_bit(HFS_BNODE_NEW, &node->flags);
438 	wake_up(&node->lock_wq);
439 
440 	return node;
441 }
442 
443 void hfs_bnode_get(struct hfs_bnode *node)
444 {
445 	if (node) {
446 		atomic_inc(&node->refcnt);
447 		hfs_dbg(BNODE_REFS, "get_node(%d:%d): %d\n",
448 			node->tree->cnid, node->this,
449 			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 		hfs_dbg(BNODE_REFS, "put_node(%d:%d): %d\n",
461 			node->tree->cnid, node->this,
462 			atomic_read(&node->refcnt));
463 		BUG_ON(!atomic_read(&node->refcnt));
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