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, int off, int len)
19 {
20 struct page *page;
21 int pagenum;
22 int bytes_read;
23 int bytes_to_read;
24
25 off += node->page_offset;
26 pagenum = off >> PAGE_SHIFT;
27 off &= ~PAGE_MASK; /* compute page offset for the first page */
28
29 for (bytes_read = 0; bytes_read < len; bytes_read += bytes_to_read) {
30 if (pagenum >= node->tree->pages_per_bnode)
31 break;
32 page = node->page[pagenum];
33 bytes_to_read = min_t(int, len - bytes_read, PAGE_SIZE - off);
34
35 memcpy_from_page(buf + bytes_read, page, off, bytes_to_read);
36
37 pagenum++;
38 off = 0; /* page offset only applies to the first page */
39 }
40 }
41
42 u16 hfs_bnode_read_u16(struct hfs_bnode *node, int off)
43 {
44 __be16 data;
45 // optimize later...
46 hfs_bnode_read(node, &data, off, 2);
47 return be16_to_cpu(data);
48 }
49
50 u8 hfs_bnode_read_u8(struct hfs_bnode *node, int off)
51 {
52 u8 data;
53 // optimize later...
54 hfs_bnode_read(node, &data, off, 1);
55 return data;
56 }
57
58 void hfs_bnode_read_key(struct hfs_bnode *node, void *key, int off)
59 {
60 struct hfs_btree *tree;
61 int key_len;
62
63 tree = node->tree;
64 if (node->type == HFS_NODE_LEAF ||
65 tree->attributes & HFS_TREE_VARIDXKEYS)
66 key_len = hfs_bnode_read_u8(node, off) + 1;
67 else
68 key_len = tree->max_key_len + 1;
69
70 hfs_bnode_read(node, key, off, key_len);
71 }
72
73 void hfs_bnode_write(struct hfs_bnode *node, void *buf, int off, int len)
74 {
75 struct page *page;
76
77 off += node->page_offset;
78 page = node->page[0];
79
80 memcpy_to_page(page, off, buf, len);
81 set_page_dirty(page);
82 }
83
84 void hfs_bnode_write_u16(struct hfs_bnode *node, int off, u16 data)
85 {
86 __be16 v = cpu_to_be16(data);
87 // optimize later...
88 hfs_bnode_write(node, &v, off, 2);
89 }
90
91 void hfs_bnode_write_u8(struct hfs_bnode *node, int off, u8 data)
92 {
93 // optimize later...
94 hfs_bnode_write(node, &data, off, 1);
95 }
96
97 void hfs_bnode_clear(struct hfs_bnode *node, int off, int len)
98 {
99 struct page *page;
100
101 off += node->page_offset;
102 page = node->page[0];
103
104 memzero_page(page, off, len);
105 set_page_dirty(page);
106 }
107
108 void hfs_bnode_copy(struct hfs_bnode *dst_node, int dst,
109 struct hfs_bnode *src_node, int src, int len)
110 {
111 struct page *src_page, *dst_page;
112
113 hfs_dbg(BNODE_MOD, "copybytes: %u,%u,%u\n", dst, src, len);
114 if (!len)
115 return;
116 src += src_node->page_offset;
117 dst += dst_node->page_offset;
118 src_page = src_node->page[0];
119 dst_page = dst_node->page[0];
120
121 memcpy_page(dst_page, dst, src_page, src, len);
122 set_page_dirty(dst_page);
123 }
124
125 void hfs_bnode_move(struct hfs_bnode *node, int dst, int src, int len)
126 {
127 struct page *page;
128 void *ptr;
129
130 hfs_dbg(BNODE_MOD, "movebytes: %u,%u,%u\n", dst, src, len);
131 if (!len)
132 return;
133 src += node->page_offset;
134 dst += node->page_offset;
135 page = node->page[0];
136 ptr = kmap_local_page(page);
137 memmove(ptr + dst, ptr + src, len);
138 kunmap_local(ptr);
139 set_page_dirty(page);
140 }
141
142 void hfs_bnode_dump(struct hfs_bnode *node)
143 {
144 struct hfs_bnode_desc desc;
145 __be32 cnid;
146 int i, off, key_off;
147
148 hfs_dbg(BNODE_MOD, "bnode: %d\n", node->this);
149 hfs_bnode_read(node, &desc, 0, sizeof(desc));
150 hfs_dbg(BNODE_MOD, "%d, %d, %d, %d, %d\n",
151 be32_to_cpu(desc.next), be32_to_cpu(desc.prev),
152 desc.type, desc.height, be16_to_cpu(desc.num_recs));
153
154 off = node->tree->node_size - 2;
155 for (i = be16_to_cpu(desc.num_recs); i >= 0; off -= 2, i--) {
156 key_off = hfs_bnode_read_u16(node, off);
157 hfs_dbg_cont(BNODE_MOD, " %d", key_off);
158 if (i && node->type == HFS_NODE_INDEX) {
159 int tmp;
160
161 if (node->tree->attributes & HFS_TREE_VARIDXKEYS)
162 tmp = (hfs_bnode_read_u8(node, key_off) | 1) + 1;
163 else
164 tmp = node->tree->max_key_len + 1;
165 hfs_dbg_cont(BNODE_MOD, " (%d,%d",
166 tmp, hfs_bnode_read_u8(node, key_off));
167 hfs_bnode_read(node, &cnid, key_off + tmp, 4);
168 hfs_dbg_cont(BNODE_MOD, ",%d)", be32_to_cpu(cnid));
169 } else if (i && node->type == HFS_NODE_LEAF) {
170 int tmp;
171
172 tmp = hfs_bnode_read_u8(node, key_off);
173 hfs_dbg_cont(BNODE_MOD, " (%d)", tmp);
174 }
175 }
176 hfs_dbg_cont(BNODE_MOD, "\n");
177 }
178
179 void hfs_bnode_unlink(struct hfs_bnode *node)
180 {
181 struct hfs_btree *tree;
182 struct hfs_bnode *tmp;
183 __be32 cnid;
184
185 tree = node->tree;
186 if (node->prev) {
187 tmp = hfs_bnode_find(tree, node->prev);
188 if (IS_ERR(tmp))
189 return;
190 tmp->next = node->next;
191 cnid = cpu_to_be32(tmp->next);
192 hfs_bnode_write(tmp, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
193 hfs_bnode_put(tmp);
194 } else if (node->type == HFS_NODE_LEAF)
195 tree->leaf_head = node->next;
196
197 if (node->next) {
198 tmp = hfs_bnode_find(tree, node->next);
199 if (IS_ERR(tmp))
200 return;
201 tmp->prev = node->prev;
202 cnid = cpu_to_be32(tmp->prev);
203 hfs_bnode_write(tmp, &cnid, offsetof(struct hfs_bnode_desc, prev), 4);
204 hfs_bnode_put(tmp);
205 } else if (node->type == HFS_NODE_LEAF)
206 tree->leaf_tail = node->prev;
207
208 // move down?
209 if (!node->prev && !node->next) {
210 printk(KERN_DEBUG "hfs_btree_del_level\n");
211 }
212 if (!node->parent) {
213 tree->root = 0;
214 tree->depth = 0;
215 }
216 set_bit(HFS_BNODE_DELETED, &node->flags);
217 }
218
219 static inline int hfs_bnode_hash(u32 num)
220 {
221 num = (num >> 16) + num;
222 num += num >> 8;
223 return num & (NODE_HASH_SIZE - 1);
224 }
225
226 struct hfs_bnode *hfs_bnode_findhash(struct hfs_btree *tree, u32 cnid)
227 {
228 struct hfs_bnode *node;
229
230 if (cnid >= tree->node_count) {
231 pr_err("request for non-existent node %d in B*Tree\n", cnid);
232 return NULL;
233 }
234
235 for (node = tree->node_hash[hfs_bnode_hash(cnid)];
236 node; node = node->next_hash) {
237 if (node->this == cnid) {
238 return node;
239 }
240 }
241 return NULL;
242 }
243
244 static struct hfs_bnode *__hfs_bnode_create(struct hfs_btree *tree, u32 cnid)
245 {
246 struct hfs_bnode *node, *node2;
247 struct address_space *mapping;
248 struct page *page;
249 int size, block, i, hash;
250 loff_t off;
251
252 if (cnid >= tree->node_count) {
253 pr_err("request for non-existent node %d in B*Tree\n", cnid);
254 return NULL;
255 }
256
257 size = sizeof(struct hfs_bnode) + tree->pages_per_bnode *
258 sizeof(struct page *);
259 node = kzalloc(size, GFP_KERNEL);
260 if (!node)
261 return NULL;
262 node->tree = tree;
263 node->this = cnid;
264 set_bit(HFS_BNODE_NEW, &node->flags);
265 atomic_set(&node->refcnt, 1);
266 hfs_dbg(BNODE_REFS, "new_node(%d:%d): 1\n",
267 node->tree->cnid, node->this);
268 init_waitqueue_head(&node->lock_wq);
269 spin_lock(&tree->hash_lock);
270 node2 = hfs_bnode_findhash(tree, cnid);
271 if (!node2) {
272 hash = hfs_bnode_hash(cnid);
273 node->next_hash = tree->node_hash[hash];
274 tree->node_hash[hash] = node;
275 tree->node_hash_cnt++;
276 } else {
277 hfs_bnode_get(node2);
278 spin_unlock(&tree->hash_lock);
279 kfree(node);
280 wait_event(node2->lock_wq, !test_bit(HFS_BNODE_NEW, &node2->flags));
281 return node2;
282 }
283 spin_unlock(&tree->hash_lock);
284
285 mapping = tree->inode->i_mapping;
286 off = (loff_t)cnid * tree->node_size;
287 block = off >> PAGE_SHIFT;
288 node->page_offset = off & ~PAGE_MASK;
289 for (i = 0; i < tree->pages_per_bnode; i++) {
290 page = read_mapping_page(mapping, block++, NULL);
291 if (IS_ERR(page))
292 goto fail;
293 node->page[i] = page;
294 }
295
296 return node;
297 fail:
298 set_bit(HFS_BNODE_ERROR, &node->flags);
299 return node;
300 }
301
302 void hfs_bnode_unhash(struct hfs_bnode *node)
303 {
304 struct hfs_bnode **p;
305
306 hfs_dbg(BNODE_REFS, "remove_node(%d:%d): %d\n",
307 node->tree->cnid, node->this, atomic_read(&node->refcnt));
308 for (p = &node->tree->node_hash[hfs_bnode_hash(node->this)];
309 *p && *p != node; p = &(*p)->next_hash)
310 ;
311 BUG_ON(!*p);
312 *p = node->next_hash;
313 node->tree->node_hash_cnt--;
314 }
315
316 /* Load a particular node out of a tree */
317 struct hfs_bnode *hfs_bnode_find(struct hfs_btree *tree, u32 num)
318 {
319 struct hfs_bnode *node;
320 struct hfs_bnode_desc *desc;
321 int i, rec_off, off, next_off;
322 int entry_size, key_size;
323
324 spin_lock(&tree->hash_lock);
325 node = hfs_bnode_findhash(tree, num);
326 if (node) {
327 hfs_bnode_get(node);
328 spin_unlock(&tree->hash_lock);
329 wait_event(node->lock_wq, !test_bit(HFS_BNODE_NEW, &node->flags));
330 if (test_bit(HFS_BNODE_ERROR, &node->flags))
331 goto node_error;
332 return node;
333 }
334 spin_unlock(&tree->hash_lock);
335 node = __hfs_bnode_create(tree, num);
336 if (!node)
337 return ERR_PTR(-ENOMEM);
338 if (test_bit(HFS_BNODE_ERROR, &node->flags))
339 goto node_error;
340 if (!test_bit(HFS_BNODE_NEW, &node->flags))
341 return node;
342
343 desc = (struct hfs_bnode_desc *)(kmap_local_page(node->page[0]) +
344 node->page_offset);
345 node->prev = be32_to_cpu(desc->prev);
346 node->next = be32_to_cpu(desc->next);
347 node->num_recs = be16_to_cpu(desc->num_recs);
348 node->type = desc->type;
349 node->height = desc->height;
350 kunmap_local(desc);
351
352 switch (node->type) {
353 case HFS_NODE_HEADER:
354 case HFS_NODE_MAP:
355 if (node->height != 0)
356 goto node_error;
357 break;
358 case HFS_NODE_LEAF:
359 if (node->height != 1)
360 goto node_error;
361 break;
362 case HFS_NODE_INDEX:
363 if (node->height <= 1 || node->height > tree->depth)
364 goto node_error;
365 break;
366 default:
367 goto node_error;
368 }
369
370 rec_off = tree->node_size - 2;
371 off = hfs_bnode_read_u16(node, rec_off);
372 if (off != sizeof(struct hfs_bnode_desc))
373 goto node_error;
374 for (i = 1; i <= node->num_recs; off = next_off, i++) {
375 rec_off -= 2;
376 next_off = hfs_bnode_read_u16(node, rec_off);
377 if (next_off <= off ||
378 next_off > tree->node_size ||
379 next_off & 1)
380 goto node_error;
381 entry_size = next_off - off;
382 if (node->type != HFS_NODE_INDEX &&
383 node->type != HFS_NODE_LEAF)
384 continue;
385 key_size = hfs_bnode_read_u8(node, off) + 1;
386 if (key_size >= entry_size /*|| key_size & 1*/)
387 goto node_error;
388 }
389 clear_bit(HFS_BNODE_NEW, &node->flags);
390 wake_up(&node->lock_wq);
391 return node;
392
393 node_error:
394 set_bit(HFS_BNODE_ERROR, &node->flags);
395 clear_bit(HFS_BNODE_NEW, &node->flags);
396 wake_up(&node->lock_wq);
397 hfs_bnode_put(node);
398 return ERR_PTR(-EIO);
399 }
400
401 void hfs_bnode_free(struct hfs_bnode *node)
402 {
403 int i;
404
405 for (i = 0; i < node->tree->pages_per_bnode; i++)
406 if (node->page[i])
407 put_page(node->page[i]);
408 kfree(node);
409 }
410
411 struct hfs_bnode *hfs_bnode_create(struct hfs_btree *tree, u32 num)
412 {
413 struct hfs_bnode *node;
414 struct page **pagep;
415 int i;
416
417 spin_lock(&tree->hash_lock);
418 node = hfs_bnode_findhash(tree, num);
419 spin_unlock(&tree->hash_lock);
420 if (node) {
421 pr_crit("new node %u already hashed?\n", num);
422 WARN_ON(1);
423 return node;
424 }
425 node = __hfs_bnode_create(tree, num);
426 if (!node)
427 return ERR_PTR(-ENOMEM);
428 if (test_bit(HFS_BNODE_ERROR, &node->flags)) {
429 hfs_bnode_put(node);
430 return ERR_PTR(-EIO);
431 }
432
433 pagep = node->page;
434 memzero_page(*pagep, node->page_offset,
435 min((int)PAGE_SIZE, (int)tree->node_size));
436 set_page_dirty(*pagep);
437 for (i = 1; i < tree->pages_per_bnode; i++) {
438 memzero_page(*++pagep, 0, PAGE_SIZE);
439 set_page_dirty(*pagep);
440 }
441 clear_bit(HFS_BNODE_NEW, &node->flags);
442 wake_up(&node->lock_wq);
443
444 return node;
445 }
446
447 void hfs_bnode_get(struct hfs_bnode *node)
448 {
449 if (node) {
450 atomic_inc(&node->refcnt);
451 hfs_dbg(BNODE_REFS, "get_node(%d:%d): %d\n",
452 node->tree->cnid, node->this,
453 atomic_read(&node->refcnt));
454 }
455 }
456
457 /* Dispose of resources used by a node */
458 void hfs_bnode_put(struct hfs_bnode *node)
459 {
460 if (node) {
461 struct hfs_btree *tree = node->tree;
462 int i;
463
464 hfs_dbg(BNODE_REFS, "put_node(%d:%d): %d\n",
465 node->tree->cnid, node->this,
466 atomic_read(&node->refcnt));
467 BUG_ON(!atomic_read(&node->refcnt));
468 if (!atomic_dec_and_lock(&node->refcnt, &tree->hash_lock))
469 return;
470 for (i = 0; i < tree->pages_per_bnode; i++) {
471 if (!node->page[i])
472 continue;
473 mark_page_accessed(node->page[i]);
474 }
475
476 if (test_bit(HFS_BNODE_DELETED, &node->flags)) {
477 hfs_bnode_unhash(node);
478 spin_unlock(&tree->hash_lock);
479 hfs_bmap_free(node);
480 hfs_bnode_free(node);
481 return;
482 }
483 spin_unlock(&tree->hash_lock);
484 }
485 }
486
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