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
hfs_bnode_read(struct hfs_bnode * node,void * buf,int off,int len)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
hfs_bnode_read_u16(struct hfs_bnode * node,int off)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
hfs_bnode_read_u8(struct hfs_bnode * node,int off)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
hfs_bnode_read_key(struct hfs_bnode * node,void * key,int off)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
hfs_bnode_write(struct hfs_bnode * node,void * buf,int off,int len)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
hfs_bnode_write_u16(struct hfs_bnode * node,int off,u16 data)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
hfs_bnode_write_u8(struct hfs_bnode * node,int off,u8 data)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
hfs_bnode_clear(struct hfs_bnode * node,int off,int len)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
hfs_bnode_copy(struct hfs_bnode * dst_node,int dst,struct hfs_bnode * src_node,int src,int len)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
hfs_bnode_move(struct hfs_bnode * node,int dst,int src,int len)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
hfs_bnode_dump(struct hfs_bnode * node)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
hfs_bnode_unlink(struct hfs_bnode * node)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
hfs_bnode_hash(u32 num)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
hfs_bnode_findhash(struct hfs_btree * tree,u32 cnid)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
__hfs_bnode_create(struct hfs_btree * tree,u32 cnid)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
hfs_bnode_unhash(struct hfs_bnode * node)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 */
hfs_bnode_find(struct hfs_btree * tree,u32 num)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
hfs_bnode_free(struct hfs_bnode * node)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
hfs_bnode_create(struct hfs_btree * tree,u32 num)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
hfs_bnode_get(struct hfs_bnode * node)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 */
hfs_bnode_put(struct hfs_bnode * 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