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(to: buf + bytes_read, page, offset: off, len: 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, buf: &data, off, len: 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, buf: &data, off, len: 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, buf: key, off, len: 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, offset: off, from: 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, buf: &v, off, len: 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, buf: &data, off, len: 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, offset: 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_off: dst, src_page, src_off: 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, buf: &desc, off: 0, len: 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, off: 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, buf: &cnid, off: key_off + tmp, len: 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, off: 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(ptr: tmp)) |
189 | return; |
190 | tmp->next = node->next; |
191 | cnid = cpu_to_be32(tmp->next); |
192 | hfs_bnode_write(node: tmp, buf: &cnid, offsetof(struct hfs_bnode_desc, next), len: 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(ptr: tmp)) |
200 | return; |
201 | tmp->prev = node->prev; |
202 | cnid = cpu_to_be32(tmp->prev); |
203 | hfs_bnode_write(node: tmp, buf: &cnid, offsetof(struct hfs_bnode_desc, prev), len: 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, addr: &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(num: 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, addr: &node->flags); |
265 | atomic_set(v: &node->refcnt, i: 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(lock: &tree->hash_lock); |
270 | node2 = hfs_bnode_findhash(tree, cnid); |
271 | if (!node2) { |
272 | hash = hfs_bnode_hash(num: 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(lock: &tree->hash_lock); |
279 | kfree(objp: node); |
280 | wait_event(node2->lock_wq, !test_bit(HFS_BNODE_NEW, &node2->flags)); |
281 | return node2; |
282 | } |
283 | spin_unlock(lock: &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, index: block++, NULL); |
291 | if (IS_ERR(ptr: page)) |
292 | goto fail; |
293 | node->page[i] = page; |
294 | } |
295 | |
296 | return node; |
297 | fail: |
298 | set_bit(HFS_BNODE_ERROR, addr: &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(num: 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(lock: &tree->hash_lock); |
325 | node = hfs_bnode_findhash(tree, cnid: num); |
326 | if (node) { |
327 | hfs_bnode_get(node); |
328 | spin_unlock(lock: &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(lock: &tree->hash_lock); |
335 | node = __hfs_bnode_create(tree, cnid: num); |
336 | if (!node) |
337 | return ERR_PTR(error: -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(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, off: 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, off: 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, addr: &node->flags); |
390 | wake_up(&node->lock_wq); |
391 | return node; |
392 | |
393 | node_error: |
394 | set_bit(HFS_BNODE_ERROR, addr: &node->flags); |
395 | clear_bit(HFS_BNODE_NEW, addr: &node->flags); |
396 | wake_up(&node->lock_wq); |
397 | hfs_bnode_put(node); |
398 | return ERR_PTR(error: -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(page: node->page[i]); |
408 | kfree(objp: 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(lock: &tree->hash_lock); |
418 | node = hfs_bnode_findhash(tree, cnid: num); |
419 | spin_unlock(lock: &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, cnid: num); |
426 | if (!node) |
427 | return ERR_PTR(error: -ENOMEM); |
428 | if (test_bit(HFS_BNODE_ERROR, &node->flags)) { |
429 | hfs_bnode_put(node); |
430 | return ERR_PTR(error: -EIO); |
431 | } |
432 | |
433 | pagep = node->page; |
434 | memzero_page(page: *pagep, offset: 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(page: *++pagep, offset: 0, PAGE_SIZE); |
439 | set_page_dirty(*pagep); |
440 | } |
441 | clear_bit(HFS_BNODE_NEW, addr: &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(v: &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(lock: &tree->hash_lock); |
479 | hfs_bmap_free(node); |
480 | hfs_bnode_free(node); |
481 | return; |
482 | } |
483 | spin_unlock(lock: &tree->hash_lock); |
484 | } |
485 | } |
486 | |