ext4: Fix spelling of CONTIG_FS_EXT3 to CONFIG_FS_EXT3
[linux-2.6.git] / fs / hfs / brec.c
1 /*
2  *  linux/fs/hfs/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 "btree.h"
12
13 static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd);
14 static int hfs_brec_update_parent(struct hfs_find_data *fd);
15 static int hfs_btree_inc_height(struct hfs_btree *tree);
16
17 /* Get the length and offset of the given record in the given node */
18 u16 hfs_brec_lenoff(struct hfs_bnode *node, u16 rec, u16 *off)
19 {
20         __be16 retval[2];
21         u16 dataoff;
22
23         dataoff = node->tree->node_size - (rec + 2) * 2;
24         hfs_bnode_read(node, retval, dataoff, 4);
25         *off = be16_to_cpu(retval[1]);
26         return be16_to_cpu(retval[0]) - *off;
27 }
28
29 /* Get the length of the key from a keyed record */
30 u16 hfs_brec_keylen(struct hfs_bnode *node, u16 rec)
31 {
32         u16 retval, recoff;
33
34         if (node->type != HFS_NODE_INDEX && node->type != HFS_NODE_LEAF)
35                 return 0;
36
37         if ((node->type == HFS_NODE_INDEX) &&
38            !(node->tree->attributes & HFS_TREE_VARIDXKEYS)) {
39                 if (node->tree->attributes & HFS_TREE_BIGKEYS)
40                         retval = node->tree->max_key_len + 2;
41                 else
42                         retval = node->tree->max_key_len + 1;
43         } else {
44                 recoff = hfs_bnode_read_u16(node, node->tree->node_size - (rec + 1) * 2);
45                 if (!recoff)
46                         return 0;
47                 if (node->tree->attributes & HFS_TREE_BIGKEYS) {
48                         retval = hfs_bnode_read_u16(node, recoff) + 2;
49                         if (retval > node->tree->max_key_len + 2) {
50                                 printk(KERN_ERR "hfs: keylen %d too large\n",
51                                         retval);
52                                 retval = 0;
53                         }
54                 } else {
55                         retval = (hfs_bnode_read_u8(node, recoff) | 1) + 1;
56                         if (retval > node->tree->max_key_len + 1) {
57                                 printk(KERN_ERR "hfs: keylen %d too large\n",
58                                         retval);
59                                 retval = 0;
60                         }
61                 }
62         }
63         return retval;
64 }
65
66 int hfs_brec_insert(struct hfs_find_data *fd, void *entry, int entry_len)
67 {
68         struct hfs_btree *tree;
69         struct hfs_bnode *node, *new_node;
70         int size, key_len, rec;
71         int data_off, end_off;
72         int idx_rec_off, data_rec_off, end_rec_off;
73         __be32 cnid;
74
75         tree = fd->tree;
76         if (!fd->bnode) {
77                 if (!tree->root)
78                         hfs_btree_inc_height(tree);
79                 fd->bnode = hfs_bnode_find(tree, tree->leaf_head);
80                 if (IS_ERR(fd->bnode))
81                         return PTR_ERR(fd->bnode);
82                 fd->record = -1;
83         }
84         new_node = NULL;
85         key_len = (fd->search_key->key_len | 1) + 1;
86 again:
87         /* new record idx and complete record size */
88         rec = fd->record + 1;
89         size = key_len + entry_len;
90
91         node = fd->bnode;
92         hfs_bnode_dump(node);
93         /* get last offset */
94         end_rec_off = tree->node_size - (node->num_recs + 1) * 2;
95         end_off = hfs_bnode_read_u16(node, end_rec_off);
96         end_rec_off -= 2;
97         dprint(DBG_BNODE_MOD, "insert_rec: %d, %d, %d, %d\n", rec, size, end_off, end_rec_off);
98         if (size > end_rec_off - end_off) {
99                 if (new_node)
100                         panic("not enough room!\n");
101                 new_node = hfs_bnode_split(fd);
102                 if (IS_ERR(new_node))
103                         return PTR_ERR(new_node);
104                 goto again;
105         }
106         if (node->type == HFS_NODE_LEAF) {
107                 tree->leaf_count++;
108                 mark_inode_dirty(tree->inode);
109         }
110         node->num_recs++;
111         /* write new last offset */
112         hfs_bnode_write_u16(node, offsetof(struct hfs_bnode_desc, num_recs), node->num_recs);
113         hfs_bnode_write_u16(node, end_rec_off, end_off + size);
114         data_off = end_off;
115         data_rec_off = end_rec_off + 2;
116         idx_rec_off = tree->node_size - (rec + 1) * 2;
117         if (idx_rec_off == data_rec_off)
118                 goto skip;
119         /* move all following entries */
120         do {
121                 data_off = hfs_bnode_read_u16(node, data_rec_off + 2);
122                 hfs_bnode_write_u16(node, data_rec_off, data_off + size);
123                 data_rec_off += 2;
124         } while (data_rec_off < idx_rec_off);
125
126         /* move data away */
127         hfs_bnode_move(node, data_off + size, data_off,
128                        end_off - data_off);
129
130 skip:
131         hfs_bnode_write(node, fd->search_key, data_off, key_len);
132         hfs_bnode_write(node, entry, data_off + key_len, entry_len);
133         hfs_bnode_dump(node);
134
135         if (new_node) {
136                 /* update parent key if we inserted a key
137                  * at the start of the first node
138                  */
139                 if (!rec && new_node != node)
140                         hfs_brec_update_parent(fd);
141
142                 hfs_bnode_put(fd->bnode);
143                 if (!new_node->parent) {
144                         hfs_btree_inc_height(tree);
145                         new_node->parent = tree->root;
146                 }
147                 fd->bnode = hfs_bnode_find(tree, new_node->parent);
148
149                 /* create index data entry */
150                 cnid = cpu_to_be32(new_node->this);
151                 entry = &cnid;
152                 entry_len = sizeof(cnid);
153
154                 /* get index key */
155                 hfs_bnode_read_key(new_node, fd->search_key, 14);
156                 __hfs_brec_find(fd->bnode, fd);
157
158                 hfs_bnode_put(new_node);
159                 new_node = NULL;
160
161                 if (tree->attributes & HFS_TREE_VARIDXKEYS)
162                         key_len = fd->search_key->key_len + 1;
163                 else {
164                         fd->search_key->key_len = tree->max_key_len;
165                         key_len = tree->max_key_len + 1;
166                 }
167                 goto again;
168         }
169
170         if (!rec)
171                 hfs_brec_update_parent(fd);
172
173         return 0;
174 }
175
176 int hfs_brec_remove(struct hfs_find_data *fd)
177 {
178         struct hfs_btree *tree;
179         struct hfs_bnode *node, *parent;
180         int end_off, rec_off, data_off, size;
181
182         tree = fd->tree;
183         node = fd->bnode;
184 again:
185         rec_off = tree->node_size - (fd->record + 2) * 2;
186         end_off = tree->node_size - (node->num_recs + 1) * 2;
187
188         if (node->type == HFS_NODE_LEAF) {
189                 tree->leaf_count--;
190                 mark_inode_dirty(tree->inode);
191         }
192         hfs_bnode_dump(node);
193         dprint(DBG_BNODE_MOD, "remove_rec: %d, %d\n", fd->record, fd->keylength + fd->entrylength);
194         if (!--node->num_recs) {
195                 hfs_bnode_unlink(node);
196                 if (!node->parent)
197                         return 0;
198                 parent = hfs_bnode_find(tree, node->parent);
199                 if (IS_ERR(parent))
200                         return PTR_ERR(parent);
201                 hfs_bnode_put(node);
202                 node = fd->bnode = parent;
203
204                 __hfs_brec_find(node, fd);
205                 goto again;
206         }
207         hfs_bnode_write_u16(node, offsetof(struct hfs_bnode_desc, num_recs), node->num_recs);
208
209         if (rec_off == end_off)
210                 goto skip;
211         size = fd->keylength + fd->entrylength;
212
213         do {
214                 data_off = hfs_bnode_read_u16(node, rec_off);
215                 hfs_bnode_write_u16(node, rec_off + 2, data_off - size);
216                 rec_off -= 2;
217         } while (rec_off >= end_off);
218
219         /* fill hole */
220         hfs_bnode_move(node, fd->keyoffset, fd->keyoffset + size,
221                        data_off - fd->keyoffset - size);
222 skip:
223         hfs_bnode_dump(node);
224         if (!fd->record)
225                 hfs_brec_update_parent(fd);
226         return 0;
227 }
228
229 static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd)
230 {
231         struct hfs_btree *tree;
232         struct hfs_bnode *node, *new_node, *next_node;
233         struct hfs_bnode_desc node_desc;
234         int num_recs, new_rec_off, new_off, old_rec_off;
235         int data_start, data_end, size;
236
237         tree = fd->tree;
238         node = fd->bnode;
239         new_node = hfs_bmap_alloc(tree);
240         if (IS_ERR(new_node))
241                 return new_node;
242         hfs_bnode_get(node);
243         dprint(DBG_BNODE_MOD, "split_nodes: %d - %d - %d\n",
244                 node->this, new_node->this, node->next);
245         new_node->next = node->next;
246         new_node->prev = node->this;
247         new_node->parent = node->parent;
248         new_node->type = node->type;
249         new_node->height = node->height;
250
251         if (node->next)
252                 next_node = hfs_bnode_find(tree, node->next);
253         else
254                 next_node = NULL;
255
256         if (IS_ERR(next_node)) {
257                 hfs_bnode_put(node);
258                 hfs_bnode_put(new_node);
259                 return next_node;
260         }
261
262         size = tree->node_size / 2 - node->num_recs * 2 - 14;
263         old_rec_off = tree->node_size - 4;
264         num_recs = 1;
265         for (;;) {
266                 data_start = hfs_bnode_read_u16(node, old_rec_off);
267                 if (data_start > size)
268                         break;
269                 old_rec_off -= 2;
270                 if (++num_recs < node->num_recs)
271                         continue;
272                 /* panic? */
273                 hfs_bnode_put(node);
274                 hfs_bnode_put(new_node);
275                 if (next_node)
276                         hfs_bnode_put(next_node);
277                 return ERR_PTR(-ENOSPC);
278         }
279
280         if (fd->record + 1 < num_recs) {
281                 /* new record is in the lower half,
282                  * so leave some more space there
283                  */
284                 old_rec_off += 2;
285                 num_recs--;
286                 data_start = hfs_bnode_read_u16(node, old_rec_off);
287         } else {
288                 hfs_bnode_put(node);
289                 hfs_bnode_get(new_node);
290                 fd->bnode = new_node;
291                 fd->record -= num_recs;
292                 fd->keyoffset -= data_start - 14;
293                 fd->entryoffset -= data_start - 14;
294         }
295         new_node->num_recs = node->num_recs - num_recs;
296         node->num_recs = num_recs;
297
298         new_rec_off = tree->node_size - 2;
299         new_off = 14;
300         size = data_start - new_off;
301         num_recs = new_node->num_recs;
302         data_end = data_start;
303         while (num_recs) {
304                 hfs_bnode_write_u16(new_node, new_rec_off, new_off);
305                 old_rec_off -= 2;
306                 new_rec_off -= 2;
307                 data_end = hfs_bnode_read_u16(node, old_rec_off);
308                 new_off = data_end - size;
309                 num_recs--;
310         }
311         hfs_bnode_write_u16(new_node, new_rec_off, new_off);
312         hfs_bnode_copy(new_node, 14, node, data_start, data_end - data_start);
313
314         /* update new bnode header */
315         node_desc.next = cpu_to_be32(new_node->next);
316         node_desc.prev = cpu_to_be32(new_node->prev);
317         node_desc.type = new_node->type;
318         node_desc.height = new_node->height;
319         node_desc.num_recs = cpu_to_be16(new_node->num_recs);
320         node_desc.reserved = 0;
321         hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
322
323         /* update previous bnode header */
324         node->next = new_node->this;
325         hfs_bnode_read(node, &node_desc, 0, sizeof(node_desc));
326         node_desc.next = cpu_to_be32(node->next);
327         node_desc.num_recs = cpu_to_be16(node->num_recs);
328         hfs_bnode_write(node, &node_desc, 0, sizeof(node_desc));
329
330         /* update next bnode header */
331         if (next_node) {
332                 next_node->prev = new_node->this;
333                 hfs_bnode_read(next_node, &node_desc, 0, sizeof(node_desc));
334                 node_desc.prev = cpu_to_be32(next_node->prev);
335                 hfs_bnode_write(next_node, &node_desc, 0, sizeof(node_desc));
336                 hfs_bnode_put(next_node);
337         } else if (node->this == tree->leaf_tail) {
338                 /* if there is no next node, this might be the new tail */
339                 tree->leaf_tail = new_node->this;
340                 mark_inode_dirty(tree->inode);
341         }
342
343         hfs_bnode_dump(node);
344         hfs_bnode_dump(new_node);
345         hfs_bnode_put(node);
346
347         return new_node;
348 }
349
350 static int hfs_brec_update_parent(struct hfs_find_data *fd)
351 {
352         struct hfs_btree *tree;
353         struct hfs_bnode *node, *new_node, *parent;
354         int newkeylen, diff;
355         int rec, rec_off, end_rec_off;
356         int start_off, end_off;
357
358         tree = fd->tree;
359         node = fd->bnode;
360         new_node = NULL;
361         if (!node->parent)
362                 return 0;
363
364 again:
365         parent = hfs_bnode_find(tree, node->parent);
366         if (IS_ERR(parent))
367                 return PTR_ERR(parent);
368         __hfs_brec_find(parent, fd);
369         hfs_bnode_dump(parent);
370         rec = fd->record;
371
372         /* size difference between old and new key */
373         if (tree->attributes & HFS_TREE_VARIDXKEYS)
374                 newkeylen = (hfs_bnode_read_u8(node, 14) | 1) + 1;
375         else
376                 fd->keylength = newkeylen = tree->max_key_len + 1;
377         dprint(DBG_BNODE_MOD, "update_rec: %d, %d, %d\n", rec, fd->keylength, newkeylen);
378
379         rec_off = tree->node_size - (rec + 2) * 2;
380         end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
381         diff = newkeylen - fd->keylength;
382         if (!diff)
383                 goto skip;
384         if (diff > 0) {
385                 end_off = hfs_bnode_read_u16(parent, end_rec_off);
386                 if (end_rec_off - end_off < diff) {
387
388                         printk(KERN_DEBUG "hfs: splitting index node...\n");
389                         fd->bnode = parent;
390                         new_node = hfs_bnode_split(fd);
391                         if (IS_ERR(new_node))
392                                 return PTR_ERR(new_node);
393                         parent = fd->bnode;
394                         rec = fd->record;
395                         rec_off = tree->node_size - (rec + 2) * 2;
396                         end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
397                 }
398         }
399
400         end_off = start_off = hfs_bnode_read_u16(parent, rec_off);
401         hfs_bnode_write_u16(parent, rec_off, start_off + diff);
402         start_off -= 4; /* move previous cnid too */
403
404         while (rec_off > end_rec_off) {
405                 rec_off -= 2;
406                 end_off = hfs_bnode_read_u16(parent, rec_off);
407                 hfs_bnode_write_u16(parent, rec_off, end_off + diff);
408         }
409         hfs_bnode_move(parent, start_off + diff, start_off,
410                        end_off - start_off);
411 skip:
412         hfs_bnode_copy(parent, fd->keyoffset, node, 14, newkeylen);
413         if (!(tree->attributes & HFS_TREE_VARIDXKEYS))
414                 hfs_bnode_write_u8(parent, fd->keyoffset, newkeylen - 1);
415         hfs_bnode_dump(parent);
416
417         hfs_bnode_put(node);
418         node = parent;
419
420         if (new_node) {
421                 __be32 cnid;
422
423                 fd->bnode = hfs_bnode_find(tree, new_node->parent);
424                 /* create index key and entry */
425                 hfs_bnode_read_key(new_node, fd->search_key, 14);
426                 cnid = cpu_to_be32(new_node->this);
427
428                 __hfs_brec_find(fd->bnode, fd);
429                 hfs_brec_insert(fd, &cnid, sizeof(cnid));
430                 hfs_bnode_put(fd->bnode);
431                 hfs_bnode_put(new_node);
432
433                 if (!rec) {
434                         if (new_node == node)
435                                 goto out;
436                         /* restore search_key */
437                         hfs_bnode_read_key(node, fd->search_key, 14);
438                 }
439         }
440
441         if (!rec && node->parent)
442                 goto again;
443 out:
444         fd->bnode = node;
445         return 0;
446 }
447
448 static int hfs_btree_inc_height(struct hfs_btree *tree)
449 {
450         struct hfs_bnode *node, *new_node;
451         struct hfs_bnode_desc node_desc;
452         int key_size, rec;
453         __be32 cnid;
454
455         node = NULL;
456         if (tree->root) {
457                 node = hfs_bnode_find(tree, tree->root);
458                 if (IS_ERR(node))
459                         return PTR_ERR(node);
460         }
461         new_node = hfs_bmap_alloc(tree);
462         if (IS_ERR(new_node)) {
463                 hfs_bnode_put(node);
464                 return PTR_ERR(new_node);
465         }
466
467         tree->root = new_node->this;
468         if (!tree->depth) {
469                 tree->leaf_head = tree->leaf_tail = new_node->this;
470                 new_node->type = HFS_NODE_LEAF;
471                 new_node->num_recs = 0;
472         } else {
473                 new_node->type = HFS_NODE_INDEX;
474                 new_node->num_recs = 1;
475         }
476         new_node->parent = 0;
477         new_node->next = 0;
478         new_node->prev = 0;
479         new_node->height = ++tree->depth;
480
481         node_desc.next = cpu_to_be32(new_node->next);
482         node_desc.prev = cpu_to_be32(new_node->prev);
483         node_desc.type = new_node->type;
484         node_desc.height = new_node->height;
485         node_desc.num_recs = cpu_to_be16(new_node->num_recs);
486         node_desc.reserved = 0;
487         hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
488
489         rec = tree->node_size - 2;
490         hfs_bnode_write_u16(new_node, rec, 14);
491
492         if (node) {
493                 /* insert old root idx into new root */
494                 node->parent = tree->root;
495                 if (node->type == HFS_NODE_LEAF ||
496                     tree->attributes & HFS_TREE_VARIDXKEYS)
497                         key_size = hfs_bnode_read_u8(node, 14) + 1;
498                 else
499                         key_size = tree->max_key_len + 1;
500                 hfs_bnode_copy(new_node, 14, node, 14, key_size);
501
502                 if (!(tree->attributes & HFS_TREE_VARIDXKEYS)) {
503                         key_size = tree->max_key_len + 1;
504                         hfs_bnode_write_u8(new_node, 14, tree->max_key_len);
505                 }
506                 key_size = (key_size + 1) & -2;
507                 cnid = cpu_to_be32(node->this);
508                 hfs_bnode_write(new_node, &cnid, 14 + key_size, 4);
509
510                 rec -= 2;
511                 hfs_bnode_write_u16(new_node, rec, 14 + key_size + 4);
512
513                 hfs_bnode_put(node);
514         }
515         hfs_bnode_put(new_node);
516         mark_inode_dirty(tree->inode);
517
518         return 0;
519 }