security: tlk_driver: kernel mem type allocation
[linux-3.10.git] / fs / hfsplus / brec.c
1 /*
2  *  linux/fs/hfsplus/brec.c
3  *
4  * Copyright (C) 2001
5  * Brad Boyer (flar@allandria.com)
6  * (C) 2003 Ardis Technologies <roman@ardistech.com>
7  *
8  * Handle individual btree records
9  */
10
11 #include "hfsplus_fs.h"
12 #include "hfsplus_raw.h"
13
14 static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd);
15 static int hfs_brec_update_parent(struct hfs_find_data *fd);
16 static int hfs_btree_inc_height(struct hfs_btree *);
17
18 /* Get the length and offset of the given record in the given node */
19 u16 hfs_brec_lenoff(struct hfs_bnode *node, u16 rec, u16 *off)
20 {
21         __be16 retval[2];
22         u16 dataoff;
23
24         dataoff = node->tree->node_size - (rec + 2) * 2;
25         hfs_bnode_read(node, retval, dataoff, 4);
26         *off = be16_to_cpu(retval[1]);
27         return be16_to_cpu(retval[0]) - *off;
28 }
29
30 /* Get the length of the key from a keyed record */
31 u16 hfs_brec_keylen(struct hfs_bnode *node, u16 rec)
32 {
33         u16 retval, recoff;
34
35         if (node->type != HFS_NODE_INDEX && node->type != HFS_NODE_LEAF)
36                 return 0;
37
38         if ((node->type == HFS_NODE_INDEX) &&
39            !(node->tree->attributes & HFS_TREE_VARIDXKEYS) &&
40            (node->tree->cnid != HFSPLUS_ATTR_CNID)) {
41                 retval = node->tree->max_key_len + 2;
42         } else {
43                 recoff = hfs_bnode_read_u16(node,
44                         node->tree->node_size - (rec + 1) * 2);
45                 if (!recoff)
46                         return 0;
47                 if (recoff > node->tree->node_size - 2) {
48                         pr_err("recoff %d too large\n", recoff);
49                         return 0;
50                 }
51
52                 retval = hfs_bnode_read_u16(node, recoff) + 2;
53                 if (retval > node->tree->max_key_len + 2) {
54                         pr_err("keylen %d too large\n",
55                                 retval);
56                         retval = 0;
57                 }
58         }
59         return retval;
60 }
61
62 int hfs_brec_insert(struct hfs_find_data *fd, void *entry, int entry_len)
63 {
64         struct hfs_btree *tree;
65         struct hfs_bnode *node, *new_node;
66         int size, key_len, rec;
67         int data_off, end_off;
68         int idx_rec_off, data_rec_off, end_rec_off;
69         __be32 cnid;
70
71         tree = fd->tree;
72         if (!fd->bnode) {
73                 if (!tree->root)
74                         hfs_btree_inc_height(tree);
75                 fd->bnode = hfs_bnode_find(tree, tree->leaf_head);
76                 if (IS_ERR(fd->bnode))
77                         return PTR_ERR(fd->bnode);
78                 fd->record = -1;
79         }
80         new_node = NULL;
81         key_len = be16_to_cpu(fd->search_key->key_len) + 2;
82 again:
83         /* new record idx and complete record size */
84         rec = fd->record + 1;
85         size = key_len + entry_len;
86
87         node = fd->bnode;
88         hfs_bnode_dump(node);
89         /* get last offset */
90         end_rec_off = tree->node_size - (node->num_recs + 1) * 2;
91         end_off = hfs_bnode_read_u16(node, end_rec_off);
92         end_rec_off -= 2;
93         hfs_dbg(BNODE_MOD, "insert_rec: %d, %d, %d, %d\n",
94                 rec, size, end_off, end_rec_off);
95         if (size > end_rec_off - end_off) {
96                 if (new_node)
97                         panic("not enough room!\n");
98                 new_node = hfs_bnode_split(fd);
99                 if (IS_ERR(new_node))
100                         return PTR_ERR(new_node);
101                 goto again;
102         }
103         if (node->type == HFS_NODE_LEAF) {
104                 tree->leaf_count++;
105                 mark_inode_dirty(tree->inode);
106         }
107         node->num_recs++;
108         /* write new last offset */
109         hfs_bnode_write_u16(node,
110                 offsetof(struct hfs_bnode_desc, num_recs),
111                 node->num_recs);
112         hfs_bnode_write_u16(node, end_rec_off, end_off + size);
113         data_off = end_off;
114         data_rec_off = end_rec_off + 2;
115         idx_rec_off = tree->node_size - (rec + 1) * 2;
116         if (idx_rec_off == data_rec_off)
117                 goto skip;
118         /* move all following entries */
119         do {
120                 data_off = hfs_bnode_read_u16(node, data_rec_off + 2);
121                 hfs_bnode_write_u16(node, data_rec_off, data_off + size);
122                 data_rec_off += 2;
123         } while (data_rec_off < idx_rec_off);
124
125         /* move data away */
126         hfs_bnode_move(node, data_off + size, data_off,
127                        end_off - data_off);
128
129 skip:
130         hfs_bnode_write(node, fd->search_key, data_off, key_len);
131         hfs_bnode_write(node, entry, data_off + key_len, entry_len);
132         hfs_bnode_dump(node);
133
134         if (new_node) {
135                 /* update parent key if we inserted a key
136                  * at the start of the first node
137                  */
138                 if (!rec && new_node != node)
139                         hfs_brec_update_parent(fd);
140
141                 hfs_bnode_put(fd->bnode);
142                 if (!new_node->parent) {
143                         hfs_btree_inc_height(tree);
144                         new_node->parent = tree->root;
145                 }
146                 fd->bnode = hfs_bnode_find(tree, new_node->parent);
147
148                 /* create index data entry */
149                 cnid = cpu_to_be32(new_node->this);
150                 entry = &cnid;
151                 entry_len = sizeof(cnid);
152
153                 /* get index key */
154                 hfs_bnode_read_key(new_node, fd->search_key, 14);
155                 __hfs_brec_find(fd->bnode, fd, hfs_find_rec_by_key);
156
157                 hfs_bnode_put(new_node);
158                 new_node = NULL;
159
160                 if ((tree->attributes & HFS_TREE_VARIDXKEYS) ||
161                                 (tree->cnid == HFSPLUS_ATTR_CNID))
162                         key_len = be16_to_cpu(fd->search_key->key_len) + 2;
163                 else {
164                         fd->search_key->key_len =
165                                 cpu_to_be16(tree->max_key_len);
166                         key_len = tree->max_key_len + 2;
167                 }
168                 goto again;
169         }
170
171         if (!rec)
172                 hfs_brec_update_parent(fd);
173
174         return 0;
175 }
176
177 int hfs_brec_remove(struct hfs_find_data *fd)
178 {
179         struct hfs_btree *tree;
180         struct hfs_bnode *node, *parent;
181         int end_off, rec_off, data_off, size;
182
183         tree = fd->tree;
184         node = fd->bnode;
185 again:
186         rec_off = tree->node_size - (fd->record + 2) * 2;
187         end_off = tree->node_size - (node->num_recs + 1) * 2;
188
189         if (node->type == HFS_NODE_LEAF) {
190                 tree->leaf_count--;
191                 mark_inode_dirty(tree->inode);
192         }
193         hfs_bnode_dump(node);
194         hfs_dbg(BNODE_MOD, "remove_rec: %d, %d\n",
195                 fd->record, fd->keylength + fd->entrylength);
196         if (!--node->num_recs) {
197                 hfs_bnode_unlink(node);
198                 if (!node->parent)
199                         return 0;
200                 parent = hfs_bnode_find(tree, node->parent);
201                 if (IS_ERR(parent))
202                         return PTR_ERR(parent);
203                 hfs_bnode_put(node);
204                 node = fd->bnode = parent;
205
206                 __hfs_brec_find(node, fd, hfs_find_rec_by_key);
207                 goto again;
208         }
209         hfs_bnode_write_u16(node,
210                 offsetof(struct hfs_bnode_desc, num_recs),
211                 node->num_recs);
212
213         if (rec_off == end_off)
214                 goto skip;
215         size = fd->keylength + fd->entrylength;
216
217         do {
218                 data_off = hfs_bnode_read_u16(node, rec_off);
219                 hfs_bnode_write_u16(node, rec_off + 2, data_off - size);
220                 rec_off -= 2;
221         } while (rec_off >= end_off);
222
223         /* fill hole */
224         hfs_bnode_move(node, fd->keyoffset, fd->keyoffset + size,
225                        data_off - fd->keyoffset - size);
226 skip:
227         hfs_bnode_dump(node);
228         if (!fd->record)
229                 hfs_brec_update_parent(fd);
230         return 0;
231 }
232
233 static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd)
234 {
235         struct hfs_btree *tree;
236         struct hfs_bnode *node, *new_node, *next_node;
237         struct hfs_bnode_desc node_desc;
238         int num_recs, new_rec_off, new_off, old_rec_off;
239         int data_start, data_end, size;
240
241         tree = fd->tree;
242         node = fd->bnode;
243         new_node = hfs_bmap_alloc(tree);
244         if (IS_ERR(new_node))
245                 return new_node;
246         hfs_bnode_get(node);
247         hfs_dbg(BNODE_MOD, "split_nodes: %d - %d - %d\n",
248                 node->this, new_node->this, node->next);
249         new_node->next = node->next;
250         new_node->prev = node->this;
251         new_node->parent = node->parent;
252         new_node->type = node->type;
253         new_node->height = node->height;
254
255         if (node->next)
256                 next_node = hfs_bnode_find(tree, node->next);
257         else
258                 next_node = NULL;
259
260         if (IS_ERR(next_node)) {
261                 hfs_bnode_put(node);
262                 hfs_bnode_put(new_node);
263                 return next_node;
264         }
265
266         size = tree->node_size / 2 - node->num_recs * 2 - 14;
267         old_rec_off = tree->node_size - 4;
268         num_recs = 1;
269         for (;;) {
270                 data_start = hfs_bnode_read_u16(node, old_rec_off);
271                 if (data_start > size)
272                         break;
273                 old_rec_off -= 2;
274                 if (++num_recs < node->num_recs)
275                         continue;
276                 /* panic? */
277                 hfs_bnode_put(node);
278                 hfs_bnode_put(new_node);
279                 if (next_node)
280                         hfs_bnode_put(next_node);
281                 return ERR_PTR(-ENOSPC);
282         }
283
284         if (fd->record + 1 < num_recs) {
285                 /* new record is in the lower half,
286                  * so leave some more space there
287                  */
288                 old_rec_off += 2;
289                 num_recs--;
290                 data_start = hfs_bnode_read_u16(node, old_rec_off);
291         } else {
292                 hfs_bnode_put(node);
293                 hfs_bnode_get(new_node);
294                 fd->bnode = new_node;
295                 fd->record -= num_recs;
296                 fd->keyoffset -= data_start - 14;
297                 fd->entryoffset -= data_start - 14;
298         }
299         new_node->num_recs = node->num_recs - num_recs;
300         node->num_recs = num_recs;
301
302         new_rec_off = tree->node_size - 2;
303         new_off = 14;
304         size = data_start - new_off;
305         num_recs = new_node->num_recs;
306         data_end = data_start;
307         while (num_recs) {
308                 hfs_bnode_write_u16(new_node, new_rec_off, new_off);
309                 old_rec_off -= 2;
310                 new_rec_off -= 2;
311                 data_end = hfs_bnode_read_u16(node, old_rec_off);
312                 new_off = data_end - size;
313                 num_recs--;
314         }
315         hfs_bnode_write_u16(new_node, new_rec_off, new_off);
316         hfs_bnode_copy(new_node, 14, node, data_start, data_end - data_start);
317
318         /* update new bnode header */
319         node_desc.next = cpu_to_be32(new_node->next);
320         node_desc.prev = cpu_to_be32(new_node->prev);
321         node_desc.type = new_node->type;
322         node_desc.height = new_node->height;
323         node_desc.num_recs = cpu_to_be16(new_node->num_recs);
324         node_desc.reserved = 0;
325         hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
326
327         /* update previous bnode header */
328         node->next = new_node->this;
329         hfs_bnode_read(node, &node_desc, 0, sizeof(node_desc));
330         node_desc.next = cpu_to_be32(node->next);
331         node_desc.num_recs = cpu_to_be16(node->num_recs);
332         hfs_bnode_write(node, &node_desc, 0, sizeof(node_desc));
333
334         /* update next bnode header */
335         if (next_node) {
336                 next_node->prev = new_node->this;
337                 hfs_bnode_read(next_node, &node_desc, 0, sizeof(node_desc));
338                 node_desc.prev = cpu_to_be32(next_node->prev);
339                 hfs_bnode_write(next_node, &node_desc, 0, sizeof(node_desc));
340                 hfs_bnode_put(next_node);
341         } else if (node->this == tree->leaf_tail) {
342                 /* if there is no next node, this might be the new tail */
343                 tree->leaf_tail = new_node->this;
344                 mark_inode_dirty(tree->inode);
345         }
346
347         hfs_bnode_dump(node);
348         hfs_bnode_dump(new_node);
349         hfs_bnode_put(node);
350
351         return new_node;
352 }
353
354 static int hfs_brec_update_parent(struct hfs_find_data *fd)
355 {
356         struct hfs_btree *tree;
357         struct hfs_bnode *node, *new_node, *parent;
358         int newkeylen, diff;
359         int rec, rec_off, end_rec_off;
360         int start_off, end_off;
361
362         tree = fd->tree;
363         node = fd->bnode;
364         new_node = NULL;
365         if (!node->parent)
366                 return 0;
367
368 again:
369         parent = hfs_bnode_find(tree, node->parent);
370         if (IS_ERR(parent))
371                 return PTR_ERR(parent);
372         __hfs_brec_find(parent, fd, hfs_find_rec_by_key);
373         hfs_bnode_dump(parent);
374         rec = fd->record;
375
376         /* size difference between old and new key */
377         if ((tree->attributes & HFS_TREE_VARIDXKEYS) ||
378                                 (tree->cnid == HFSPLUS_ATTR_CNID))
379                 newkeylen = hfs_bnode_read_u16(node, 14) + 2;
380         else
381                 fd->keylength = newkeylen = tree->max_key_len + 2;
382         hfs_dbg(BNODE_MOD, "update_rec: %d, %d, %d\n",
383                 rec, fd->keylength, newkeylen);
384
385         rec_off = tree->node_size - (rec + 2) * 2;
386         end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
387         diff = newkeylen - fd->keylength;
388         if (!diff)
389                 goto skip;
390         if (diff > 0) {
391                 end_off = hfs_bnode_read_u16(parent, end_rec_off);
392                 if (end_rec_off - end_off < diff) {
393
394                         hfs_dbg(BNODE_MOD, "splitting index node\n");
395                         fd->bnode = parent;
396                         new_node = hfs_bnode_split(fd);
397                         if (IS_ERR(new_node))
398                                 return PTR_ERR(new_node);
399                         parent = fd->bnode;
400                         rec = fd->record;
401                         rec_off = tree->node_size - (rec + 2) * 2;
402                         end_rec_off = tree->node_size -
403                                 (parent->num_recs + 1) * 2;
404                 }
405         }
406
407         end_off = start_off = hfs_bnode_read_u16(parent, rec_off);
408         hfs_bnode_write_u16(parent, rec_off, start_off + diff);
409         start_off -= 4; /* move previous cnid too */
410
411         while (rec_off > end_rec_off) {
412                 rec_off -= 2;
413                 end_off = hfs_bnode_read_u16(parent, rec_off);
414                 hfs_bnode_write_u16(parent, rec_off, end_off + diff);
415         }
416         hfs_bnode_move(parent, start_off + diff, start_off,
417                        end_off - start_off);
418 skip:
419         hfs_bnode_copy(parent, fd->keyoffset, node, 14, newkeylen);
420         hfs_bnode_dump(parent);
421
422         hfs_bnode_put(node);
423         node = parent;
424
425         if (new_node) {
426                 __be32 cnid;
427
428                 fd->bnode = hfs_bnode_find(tree, new_node->parent);
429                 /* create index key and entry */
430                 hfs_bnode_read_key(new_node, fd->search_key, 14);
431                 cnid = cpu_to_be32(new_node->this);
432
433                 __hfs_brec_find(fd->bnode, fd, hfs_find_rec_by_key);
434                 hfs_brec_insert(fd, &cnid, sizeof(cnid));
435                 hfs_bnode_put(fd->bnode);
436                 hfs_bnode_put(new_node);
437
438                 if (!rec) {
439                         if (new_node == node)
440                                 goto out;
441                         /* restore search_key */
442                         hfs_bnode_read_key(node, fd->search_key, 14);
443                 }
444         }
445
446         if (!rec && node->parent)
447                 goto again;
448 out:
449         fd->bnode = node;
450         return 0;
451 }
452
453 static int hfs_btree_inc_height(struct hfs_btree *tree)
454 {
455         struct hfs_bnode *node, *new_node;
456         struct hfs_bnode_desc node_desc;
457         int key_size, rec;
458         __be32 cnid;
459
460         node = NULL;
461         if (tree->root) {
462                 node = hfs_bnode_find(tree, tree->root);
463                 if (IS_ERR(node))
464                         return PTR_ERR(node);
465         }
466         new_node = hfs_bmap_alloc(tree);
467         if (IS_ERR(new_node)) {
468                 hfs_bnode_put(node);
469                 return PTR_ERR(new_node);
470         }
471
472         tree->root = new_node->this;
473         if (!tree->depth) {
474                 tree->leaf_head = tree->leaf_tail = new_node->this;
475                 new_node->type = HFS_NODE_LEAF;
476                 new_node->num_recs = 0;
477         } else {
478                 new_node->type = HFS_NODE_INDEX;
479                 new_node->num_recs = 1;
480         }
481         new_node->parent = 0;
482         new_node->next = 0;
483         new_node->prev = 0;
484         new_node->height = ++tree->depth;
485
486         node_desc.next = cpu_to_be32(new_node->next);
487         node_desc.prev = cpu_to_be32(new_node->prev);
488         node_desc.type = new_node->type;
489         node_desc.height = new_node->height;
490         node_desc.num_recs = cpu_to_be16(new_node->num_recs);
491         node_desc.reserved = 0;
492         hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
493
494         rec = tree->node_size - 2;
495         hfs_bnode_write_u16(new_node, rec, 14);
496
497         if (node) {
498                 /* insert old root idx into new root */
499                 node->parent = tree->root;
500                 if (node->type == HFS_NODE_LEAF ||
501                                 tree->attributes & HFS_TREE_VARIDXKEYS ||
502                                 tree->cnid == HFSPLUS_ATTR_CNID)
503                         key_size = hfs_bnode_read_u16(node, 14) + 2;
504                 else
505                         key_size = tree->max_key_len + 2;
506                 hfs_bnode_copy(new_node, 14, node, 14, key_size);
507
508                 if (!(tree->attributes & HFS_TREE_VARIDXKEYS) &&
509                                 (tree->cnid != HFSPLUS_ATTR_CNID)) {
510                         key_size = tree->max_key_len + 2;
511                         hfs_bnode_write_u16(new_node, 14, tree->max_key_len);
512                 }
513                 cnid = cpu_to_be32(node->this);
514                 hfs_bnode_write(new_node, &cnid, 14 + key_size, 4);
515
516                 rec -= 2;
517                 hfs_bnode_write_u16(new_node, rec, 14 + key_size + 4);
518
519                 hfs_bnode_put(node);
520         }
521         hfs_bnode_put(new_node);
522         mark_inode_dirty(tree->inode);
523
524         return 0;
525 }