1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * linux/fs/hfsplus/brec.c
4 *
5 * Copyright (C) 2001
6 * Brad Boyer (flar@allandria.com)
7 * (C) 2003 Ardis Technologies <roman@ardistech.com>
8 *
9 * Handle individual btree records
10 */
11
12 #include "hfsplus_fs.h"
13 #include "hfsplus_raw.h"
14
15 static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd);
16 static int hfs_brec_update_parent(struct hfs_find_data *fd);
17 static int hfs_btree_inc_height(struct hfs_btree *);
18
19 /* Get the length and offset of the given record in the given node */
hfs_brec_lenoff(struct hfs_bnode * node,u16 rec,u16 * off)20 u16 hfs_brec_lenoff(struct hfs_bnode *node, u16 rec, u16 *off)
21 {
22 __be16 retval[2];
23 u16 dataoff;
24
25 dataoff = node->tree->node_size - (rec + 2) * 2;
26 hfs_bnode_read(node, retval, dataoff, 4);
27 *off = be16_to_cpu(retval[1]);
28 return be16_to_cpu(retval[0]) - *off;
29 }
30
31 /* Get the length of the key from a keyed record */
hfs_brec_keylen(struct hfs_bnode * node,u16 rec)32 u16 hfs_brec_keylen(struct hfs_bnode *node, u16 rec)
33 {
34 u16 retval, recoff;
35
36 if (node->type != HFS_NODE_INDEX && node->type != HFS_NODE_LEAF)
37 return 0;
38
39 if ((node->type == HFS_NODE_INDEX) &&
40 !(node->tree->attributes & HFS_TREE_VARIDXKEYS) &&
41 (node->tree->cnid != HFSPLUS_ATTR_CNID)) {
42 retval = node->tree->max_key_len + 2;
43 } else {
44 recoff = hfs_bnode_read_u16(node,
45 node->tree->node_size - (rec + 1) * 2);
46 if (!recoff)
47 return 0;
48 if (recoff > node->tree->node_size - 2) {
49 pr_err("recoff %d too large\n", recoff);
50 return 0;
51 }
52
53 retval = hfs_bnode_read_u16(node, recoff) + 2;
54 if (retval > node->tree->max_key_len + 2) {
55 pr_err("keylen %d too large\n",
56 retval);
57 retval = 0;
58 }
59 }
60 return retval;
61 }
62
hfs_brec_insert(struct hfs_find_data * fd,void * entry,int entry_len)63 int hfs_brec_insert(struct hfs_find_data *fd, void *entry, int entry_len)
64 {
65 struct hfs_btree *tree;
66 struct hfs_bnode *node, *new_node;
67 int size, key_len, rec;
68 int data_off, end_off;
69 int idx_rec_off, data_rec_off, end_rec_off;
70 __be32 cnid;
71
72 tree = fd->tree;
73 if (!fd->bnode) {
74 if (!tree->root)
75 hfs_btree_inc_height(tree);
76 node = hfs_bnode_find(tree, tree->leaf_head);
77 if (IS_ERR(node))
78 return PTR_ERR(node);
79 fd->bnode = node;
80 fd->record = -1;
81 }
82 new_node = NULL;
83 key_len = be16_to_cpu(fd->search_key->key_len) + 2;
84 again:
85 /* new record idx and complete record size */
86 rec = fd->record + 1;
87 size = key_len + entry_len;
88
89 node = fd->bnode;
90 hfs_bnode_dump(node);
91 /* get last offset */
92 end_rec_off = tree->node_size - (node->num_recs + 1) * 2;
93 end_off = hfs_bnode_read_u16(node, end_rec_off);
94 end_rec_off -= 2;
95 hfs_dbg(BNODE_MOD, "insert_rec: %d, %d, %d, %d\n",
96 rec, size, end_off, end_rec_off);
97 if (size > end_rec_off - end_off) {
98 if (new_node)
99 panic("not enough room!\n");
100 new_node = hfs_bnode_split(fd);
101 if (IS_ERR(new_node))
102 return PTR_ERR(new_node);
103 goto again;
104 }
105 if (node->type == HFS_NODE_LEAF) {
106 tree->leaf_count++;
107 mark_inode_dirty(tree->inode);
108 }
109 node->num_recs++;
110 /* write new last offset */
111 hfs_bnode_write_u16(node,
112 offsetof(struct hfs_bnode_desc, num_recs),
113 node->num_recs);
114 hfs_bnode_write_u16(node, end_rec_off, end_off + size);
115 data_off = end_off;
116 data_rec_off = end_rec_off + 2;
117 idx_rec_off = tree->node_size - (rec + 1) * 2;
118 if (idx_rec_off == data_rec_off)
119 goto skip;
120 /* move all following entries */
121 do {
122 data_off = hfs_bnode_read_u16(node, data_rec_off + 2);
123 hfs_bnode_write_u16(node, data_rec_off, data_off + size);
124 data_rec_off += 2;
125 } while (data_rec_off < idx_rec_off);
126
127 /* move data away */
128 hfs_bnode_move(node, data_off + size, data_off,
129 end_off - data_off);
130
131 skip:
132 hfs_bnode_write(node, fd->search_key, data_off, key_len);
133 hfs_bnode_write(node, entry, data_off + key_len, entry_len);
134 hfs_bnode_dump(node);
135
136 /*
137 * update parent key if we inserted a key
138 * at the start of the node and it is not the new node
139 */
140 if (!rec && new_node != node) {
141 hfs_bnode_read_key(node, fd->search_key, data_off + size);
142 hfs_brec_update_parent(fd);
143 }
144
145 if (new_node) {
146 hfs_bnode_put(fd->bnode);
147 if (!new_node->parent) {
148 hfs_btree_inc_height(tree);
149 new_node->parent = tree->root;
150 }
151 fd->bnode = hfs_bnode_find(tree, new_node->parent);
152
153 /* create index data entry */
154 cnid = cpu_to_be32(new_node->this);
155 entry = &cnid;
156 entry_len = sizeof(cnid);
157
158 /* get index key */
159 hfs_bnode_read_key(new_node, fd->search_key, 14);
160 __hfs_brec_find(fd->bnode, fd, hfs_find_rec_by_key);
161
162 hfs_bnode_put(new_node);
163 new_node = NULL;
164
165 if ((tree->attributes & HFS_TREE_VARIDXKEYS) ||
166 (tree->cnid == HFSPLUS_ATTR_CNID))
167 key_len = be16_to_cpu(fd->search_key->key_len) + 2;
168 else {
169 fd->search_key->key_len =
170 cpu_to_be16(tree->max_key_len);
171 key_len = tree->max_key_len + 2;
172 }
173 goto again;
174 }
175
176 return 0;
177 }
178
hfs_brec_remove(struct hfs_find_data * fd)179 int hfs_brec_remove(struct hfs_find_data *fd)
180 {
181 struct hfs_btree *tree;
182 struct hfs_bnode *node, *parent;
183 int end_off, rec_off, data_off, size;
184
185 tree = fd->tree;
186 node = fd->bnode;
187 again:
188 rec_off = tree->node_size - (fd->record + 2) * 2;
189 end_off = tree->node_size - (node->num_recs + 1) * 2;
190
191 if (node->type == HFS_NODE_LEAF) {
192 tree->leaf_count--;
193 mark_inode_dirty(tree->inode);
194 }
195 hfs_bnode_dump(node);
196 hfs_dbg(BNODE_MOD, "remove_rec: %d, %d\n",
197 fd->record, fd->keylength + fd->entrylength);
198 if (!--node->num_recs) {
199 hfs_bnode_unlink(node);
200 if (!node->parent)
201 return 0;
202 parent = hfs_bnode_find(tree, node->parent);
203 if (IS_ERR(parent))
204 return PTR_ERR(parent);
205 hfs_bnode_put(node);
206 node = fd->bnode = parent;
207
208 __hfs_brec_find(node, fd, hfs_find_rec_by_key);
209 goto again;
210 }
211 hfs_bnode_write_u16(node,
212 offsetof(struct hfs_bnode_desc, num_recs),
213 node->num_recs);
214
215 if (rec_off == end_off)
216 goto skip;
217 size = fd->keylength + fd->entrylength;
218
219 do {
220 data_off = hfs_bnode_read_u16(node, rec_off);
221 hfs_bnode_write_u16(node, rec_off + 2, data_off - size);
222 rec_off -= 2;
223 } while (rec_off >= end_off);
224
225 /* fill hole */
226 hfs_bnode_move(node, fd->keyoffset, fd->keyoffset + size,
227 data_off - fd->keyoffset - size);
228 skip:
229 hfs_bnode_dump(node);
230 if (!fd->record)
231 hfs_brec_update_parent(fd);
232 return 0;
233 }
234
hfs_bnode_split(struct hfs_find_data * fd)235 static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd)
236 {
237 struct hfs_btree *tree;
238 struct hfs_bnode *node, *new_node, *next_node;
239 struct hfs_bnode_desc node_desc;
240 int num_recs, new_rec_off, new_off, old_rec_off;
241 int data_start, data_end, size;
242
243 tree = fd->tree;
244 node = fd->bnode;
245 new_node = hfs_bmap_alloc(tree);
246 if (IS_ERR(new_node))
247 return new_node;
248 hfs_bnode_get(node);
249 hfs_dbg(BNODE_MOD, "split_nodes: %d - %d - %d\n",
250 node->this, new_node->this, node->next);
251 new_node->next = node->next;
252 new_node->prev = node->this;
253 new_node->parent = node->parent;
254 new_node->type = node->type;
255 new_node->height = node->height;
256
257 if (node->next)
258 next_node = hfs_bnode_find(tree, node->next);
259 else
260 next_node = NULL;
261
262 if (IS_ERR(next_node)) {
263 hfs_bnode_put(node);
264 hfs_bnode_put(new_node);
265 return next_node;
266 }
267
268 size = tree->node_size / 2 - node->num_recs * 2 - 14;
269 old_rec_off = tree->node_size - 4;
270 num_recs = 1;
271 for (;;) {
272 data_start = hfs_bnode_read_u16(node, old_rec_off);
273 if (data_start > size)
274 break;
275 old_rec_off -= 2;
276 if (++num_recs < node->num_recs)
277 continue;
278 /* panic? */
279 hfs_bnode_put(node);
280 hfs_bnode_put(new_node);
281 if (next_node)
282 hfs_bnode_put(next_node);
283 return ERR_PTR(-ENOSPC);
284 }
285
286 if (fd->record + 1 < num_recs) {
287 /* new record is in the lower half,
288 * so leave some more space there
289 */
290 old_rec_off += 2;
291 num_recs--;
292 data_start = hfs_bnode_read_u16(node, old_rec_off);
293 } else {
294 hfs_bnode_put(node);
295 hfs_bnode_get(new_node);
296 fd->bnode = new_node;
297 fd->record -= num_recs;
298 fd->keyoffset -= data_start - 14;
299 fd->entryoffset -= data_start - 14;
300 }
301 new_node->num_recs = node->num_recs - num_recs;
302 node->num_recs = num_recs;
303
304 new_rec_off = tree->node_size - 2;
305 new_off = 14;
306 size = data_start - new_off;
307 num_recs = new_node->num_recs;
308 data_end = data_start;
309 while (num_recs) {
310 hfs_bnode_write_u16(new_node, new_rec_off, new_off);
311 old_rec_off -= 2;
312 new_rec_off -= 2;
313 data_end = hfs_bnode_read_u16(node, old_rec_off);
314 new_off = data_end - size;
315 num_recs--;
316 }
317 hfs_bnode_write_u16(new_node, new_rec_off, new_off);
318 hfs_bnode_copy(new_node, 14, node, data_start, data_end - data_start);
319
320 /* update new bnode header */
321 node_desc.next = cpu_to_be32(new_node->next);
322 node_desc.prev = cpu_to_be32(new_node->prev);
323 node_desc.type = new_node->type;
324 node_desc.height = new_node->height;
325 node_desc.num_recs = cpu_to_be16(new_node->num_recs);
326 node_desc.reserved = 0;
327 hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
328
329 /* update previous bnode header */
330 node->next = new_node->this;
331 hfs_bnode_read(node, &node_desc, 0, sizeof(node_desc));
332 node_desc.next = cpu_to_be32(node->next);
333 node_desc.num_recs = cpu_to_be16(node->num_recs);
334 hfs_bnode_write(node, &node_desc, 0, sizeof(node_desc));
335
336 /* update next bnode header */
337 if (next_node) {
338 next_node->prev = new_node->this;
339 hfs_bnode_read(next_node, &node_desc, 0, sizeof(node_desc));
340 node_desc.prev = cpu_to_be32(next_node->prev);
341 hfs_bnode_write(next_node, &node_desc, 0, sizeof(node_desc));
342 hfs_bnode_put(next_node);
343 } else if (node->this == tree->leaf_tail) {
344 /* if there is no next node, this might be the new tail */
345 tree->leaf_tail = new_node->this;
346 mark_inode_dirty(tree->inode);
347 }
348
349 hfs_bnode_dump(node);
350 hfs_bnode_dump(new_node);
351 hfs_bnode_put(node);
352
353 return new_node;
354 }
355
hfs_brec_update_parent(struct hfs_find_data * fd)356 static int hfs_brec_update_parent(struct hfs_find_data *fd)
357 {
358 struct hfs_btree *tree;
359 struct hfs_bnode *node, *new_node, *parent;
360 int newkeylen, diff;
361 int rec, rec_off, end_rec_off;
362 int start_off, end_off;
363
364 tree = fd->tree;
365 node = fd->bnode;
366 new_node = NULL;
367 if (!node->parent)
368 return 0;
369
370 again:
371 parent = hfs_bnode_find(tree, node->parent);
372 if (IS_ERR(parent))
373 return PTR_ERR(parent);
374 __hfs_brec_find(parent, fd, hfs_find_rec_by_key);
375 if (fd->record < 0)
376 return -ENOENT;
377 hfs_bnode_dump(parent);
378 rec = fd->record;
379
380 /* size difference between old and new key */
381 if ((tree->attributes & HFS_TREE_VARIDXKEYS) ||
382 (tree->cnid == HFSPLUS_ATTR_CNID))
383 newkeylen = hfs_bnode_read_u16(node, 14) + 2;
384 else
385 fd->keylength = newkeylen = tree->max_key_len + 2;
386 hfs_dbg(BNODE_MOD, "update_rec: %d, %d, %d\n",
387 rec, fd->keylength, newkeylen);
388
389 rec_off = tree->node_size - (rec + 2) * 2;
390 end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
391 diff = newkeylen - fd->keylength;
392 if (!diff)
393 goto skip;
394 if (diff > 0) {
395 end_off = hfs_bnode_read_u16(parent, end_rec_off);
396 if (end_rec_off - end_off < diff) {
397
398 hfs_dbg(BNODE_MOD, "splitting index node\n");
399 fd->bnode = parent;
400 new_node = hfs_bnode_split(fd);
401 if (IS_ERR(new_node))
402 return PTR_ERR(new_node);
403 parent = fd->bnode;
404 rec = fd->record;
405 rec_off = tree->node_size - (rec + 2) * 2;
406 end_rec_off = tree->node_size -
407 (parent->num_recs + 1) * 2;
408 }
409 }
410
411 end_off = start_off = hfs_bnode_read_u16(parent, rec_off);
412 hfs_bnode_write_u16(parent, rec_off, start_off + diff);
413 start_off -= 4; /* move previous cnid too */
414
415 while (rec_off > end_rec_off) {
416 rec_off -= 2;
417 end_off = hfs_bnode_read_u16(parent, rec_off);
418 hfs_bnode_write_u16(parent, rec_off, end_off + diff);
419 }
420 hfs_bnode_move(parent, start_off + diff, start_off,
421 end_off - start_off);
422 skip:
423 hfs_bnode_copy(parent, fd->keyoffset, node, 14, newkeylen);
424 hfs_bnode_dump(parent);
425
426 hfs_bnode_put(node);
427 node = parent;
428
429 if (new_node) {
430 __be32 cnid;
431
432 if (!new_node->parent) {
433 hfs_btree_inc_height(tree);
434 new_node->parent = tree->root;
435 }
436 fd->bnode = hfs_bnode_find(tree, new_node->parent);
437 /* create index key and entry */
438 hfs_bnode_read_key(new_node, fd->search_key, 14);
439 cnid = cpu_to_be32(new_node->this);
440
441 __hfs_brec_find(fd->bnode, fd, hfs_find_rec_by_key);
442 hfs_brec_insert(fd, &cnid, sizeof(cnid));
443 hfs_bnode_put(fd->bnode);
444 hfs_bnode_put(new_node);
445
446 if (!rec) {
447 if (new_node == node)
448 goto out;
449 /* restore search_key */
450 hfs_bnode_read_key(node, fd->search_key, 14);
451 }
452 new_node = NULL;
453 }
454
455 if (!rec && node->parent)
456 goto again;
457 out:
458 fd->bnode = node;
459 return 0;
460 }
461
hfs_btree_inc_height(struct hfs_btree * tree)462 static int hfs_btree_inc_height(struct hfs_btree *tree)
463 {
464 struct hfs_bnode *node, *new_node;
465 struct hfs_bnode_desc node_desc;
466 int key_size, rec;
467 __be32 cnid;
468
469 node = NULL;
470 if (tree->root) {
471 node = hfs_bnode_find(tree, tree->root);
472 if (IS_ERR(node))
473 return PTR_ERR(node);
474 }
475 new_node = hfs_bmap_alloc(tree);
476 if (IS_ERR(new_node)) {
477 hfs_bnode_put(node);
478 return PTR_ERR(new_node);
479 }
480
481 tree->root = new_node->this;
482 if (!tree->depth) {
483 tree->leaf_head = tree->leaf_tail = new_node->this;
484 new_node->type = HFS_NODE_LEAF;
485 new_node->num_recs = 0;
486 } else {
487 new_node->type = HFS_NODE_INDEX;
488 new_node->num_recs = 1;
489 }
490 new_node->parent = 0;
491 new_node->next = 0;
492 new_node->prev = 0;
493 new_node->height = ++tree->depth;
494
495 node_desc.next = cpu_to_be32(new_node->next);
496 node_desc.prev = cpu_to_be32(new_node->prev);
497 node_desc.type = new_node->type;
498 node_desc.height = new_node->height;
499 node_desc.num_recs = cpu_to_be16(new_node->num_recs);
500 node_desc.reserved = 0;
501 hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
502
503 rec = tree->node_size - 2;
504 hfs_bnode_write_u16(new_node, rec, 14);
505
506 if (node) {
507 /* insert old root idx into new root */
508 node->parent = tree->root;
509 if (node->type == HFS_NODE_LEAF ||
510 tree->attributes & HFS_TREE_VARIDXKEYS ||
511 tree->cnid == HFSPLUS_ATTR_CNID)
512 key_size = hfs_bnode_read_u16(node, 14) + 2;
513 else
514 key_size = tree->max_key_len + 2;
515 hfs_bnode_copy(new_node, 14, node, 14, key_size);
516
517 if (!(tree->attributes & HFS_TREE_VARIDXKEYS) &&
518 (tree->cnid != HFSPLUS_ATTR_CNID)) {
519 key_size = tree->max_key_len + 2;
520 hfs_bnode_write_u16(new_node, 14, tree->max_key_len);
521 }
522 cnid = cpu_to_be32(node->this);
523 hfs_bnode_write(new_node, &cnid, 14 + key_size, 4);
524
525 rec -= 2;
526 hfs_bnode_write_u16(new_node, rec, 14 + key_size + 4);
527
528 hfs_bnode_put(node);
529 }
530 hfs_bnode_put(new_node);
531 mark_inode_dirty(tree->inode);
532
533 return 0;
534 }
535