878bf25dbc6a8c60d8ffc9736c0d6bf5c20ed699
[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;
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         size = tree->node_size / 2 - node->num_recs * 2 - 14;
252         old_rec_off = tree->node_size - 4;
253         num_recs = 1;
254         for (;;) {
255                 data_start = hfs_bnode_read_u16(node, old_rec_off);
256                 if (data_start > size)
257                         break;
258                 old_rec_off -= 2;
259                 if (++num_recs < node->num_recs)
260                         continue;
261                 /* panic? */
262                 hfs_bnode_put(node);
263                 hfs_bnode_put(new_node);
264                 return ERR_PTR(-ENOSPC);
265         }
266
267         if (fd->record + 1 < num_recs) {
268                 /* new record is in the lower half,
269                  * so leave some more space there
270                  */
271                 old_rec_off += 2;
272                 num_recs--;
273                 data_start = hfs_bnode_read_u16(node, old_rec_off);
274         } else {
275                 hfs_bnode_put(node);
276                 hfs_bnode_get(new_node);
277                 fd->bnode = new_node;
278                 fd->record -= num_recs;
279                 fd->keyoffset -= data_start - 14;
280                 fd->entryoffset -= data_start - 14;
281         }
282         new_node->num_recs = node->num_recs - num_recs;
283         node->num_recs = num_recs;
284
285         new_rec_off = tree->node_size - 2;
286         new_off = 14;
287         size = data_start - new_off;
288         num_recs = new_node->num_recs;
289         data_end = data_start;
290         while (num_recs) {
291                 hfs_bnode_write_u16(new_node, new_rec_off, new_off);
292                 old_rec_off -= 2;
293                 new_rec_off -= 2;
294                 data_end = hfs_bnode_read_u16(node, old_rec_off);
295                 new_off = data_end - size;
296                 num_recs--;
297         }
298         hfs_bnode_write_u16(new_node, new_rec_off, new_off);
299         hfs_bnode_copy(new_node, 14, node, data_start, data_end - data_start);
300
301         /* update new bnode header */
302         node_desc.next = cpu_to_be32(new_node->next);
303         node_desc.prev = cpu_to_be32(new_node->prev);
304         node_desc.type = new_node->type;
305         node_desc.height = new_node->height;
306         node_desc.num_recs = cpu_to_be16(new_node->num_recs);
307         node_desc.reserved = 0;
308         hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
309
310         /* update previous bnode header */
311         node->next = new_node->this;
312         hfs_bnode_read(node, &node_desc, 0, sizeof(node_desc));
313         node_desc.next = cpu_to_be32(node->next);
314         node_desc.num_recs = cpu_to_be16(node->num_recs);
315         hfs_bnode_write(node, &node_desc, 0, sizeof(node_desc));
316
317         /* update next bnode header */
318         if (new_node->next) {
319                 struct hfs_bnode *next_node = hfs_bnode_find(tree, new_node->next);
320                 next_node->prev = new_node->this;
321                 hfs_bnode_read(next_node, &node_desc, 0, sizeof(node_desc));
322                 node_desc.prev = cpu_to_be32(next_node->prev);
323                 hfs_bnode_write(next_node, &node_desc, 0, sizeof(node_desc));
324                 hfs_bnode_put(next_node);
325         } else if (node->this == tree->leaf_tail) {
326                 /* if there is no next node, this might be the new tail */
327                 tree->leaf_tail = new_node->this;
328                 mark_inode_dirty(tree->inode);
329         }
330
331         hfs_bnode_dump(node);
332         hfs_bnode_dump(new_node);
333         hfs_bnode_put(node);
334
335         return new_node;
336 }
337
338 static int hfs_brec_update_parent(struct hfs_find_data *fd)
339 {
340         struct hfs_btree *tree;
341         struct hfs_bnode *node, *new_node, *parent;
342         int newkeylen, diff;
343         int rec, rec_off, end_rec_off;
344         int start_off, end_off;
345
346         tree = fd->tree;
347         node = fd->bnode;
348         new_node = NULL;
349         if (!node->parent)
350                 return 0;
351
352 again:
353         parent = hfs_bnode_find(tree, node->parent);
354         if (IS_ERR(parent))
355                 return PTR_ERR(parent);
356         __hfs_brec_find(parent, fd);
357         hfs_bnode_dump(parent);
358         rec = fd->record;
359
360         /* size difference between old and new key */
361         if (tree->attributes & HFS_TREE_VARIDXKEYS)
362                 newkeylen = (hfs_bnode_read_u8(node, 14) | 1) + 1;
363         else
364                 fd->keylength = newkeylen = tree->max_key_len + 1;
365         dprint(DBG_BNODE_MOD, "update_rec: %d, %d, %d\n", rec, fd->keylength, newkeylen);
366
367         rec_off = tree->node_size - (rec + 2) * 2;
368         end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
369         diff = newkeylen - fd->keylength;
370         if (!diff)
371                 goto skip;
372         if (diff > 0) {
373                 end_off = hfs_bnode_read_u16(parent, end_rec_off);
374                 if (end_rec_off - end_off < diff) {
375
376                         printk(KERN_DEBUG "hfs: splitting index node...\n");
377                         fd->bnode = parent;
378                         new_node = hfs_bnode_split(fd);
379                         if (IS_ERR(new_node))
380                                 return PTR_ERR(new_node);
381                         parent = fd->bnode;
382                         rec = fd->record;
383                         rec_off = tree->node_size - (rec + 2) * 2;
384                         end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
385                 }
386         }
387
388         end_off = start_off = hfs_bnode_read_u16(parent, rec_off);
389         hfs_bnode_write_u16(parent, rec_off, start_off + diff);
390         start_off -= 4; /* move previous cnid too */
391
392         while (rec_off > end_rec_off) {
393                 rec_off -= 2;
394                 end_off = hfs_bnode_read_u16(parent, rec_off);
395                 hfs_bnode_write_u16(parent, rec_off, end_off + diff);
396         }
397         hfs_bnode_move(parent, start_off + diff, start_off,
398                        end_off - start_off);
399 skip:
400         hfs_bnode_copy(parent, fd->keyoffset, node, 14, newkeylen);
401         if (!(tree->attributes & HFS_TREE_VARIDXKEYS))
402                 hfs_bnode_write_u8(parent, fd->keyoffset, newkeylen - 1);
403         hfs_bnode_dump(parent);
404
405         hfs_bnode_put(node);
406         node = parent;
407
408         if (new_node) {
409                 __be32 cnid;
410
411                 fd->bnode = hfs_bnode_find(tree, new_node->parent);
412                 /* create index key and entry */
413                 hfs_bnode_read_key(new_node, fd->search_key, 14);
414                 cnid = cpu_to_be32(new_node->this);
415
416                 __hfs_brec_find(fd->bnode, fd);
417                 hfs_brec_insert(fd, &cnid, sizeof(cnid));
418                 hfs_bnode_put(fd->bnode);
419                 hfs_bnode_put(new_node);
420
421                 if (!rec) {
422                         if (new_node == node)
423                                 goto out;
424                         /* restore search_key */
425                         hfs_bnode_read_key(node, fd->search_key, 14);
426                 }
427         }
428
429         if (!rec && node->parent)
430                 goto again;
431 out:
432         fd->bnode = node;
433         return 0;
434 }
435
436 static int hfs_btree_inc_height(struct hfs_btree *tree)
437 {
438         struct hfs_bnode *node, *new_node;
439         struct hfs_bnode_desc node_desc;
440         int key_size, rec;
441         __be32 cnid;
442
443         node = NULL;
444         if (tree->root) {
445                 node = hfs_bnode_find(tree, tree->root);
446                 if (IS_ERR(node))
447                         return PTR_ERR(node);
448         }
449         new_node = hfs_bmap_alloc(tree);
450         if (IS_ERR(new_node)) {
451                 hfs_bnode_put(node);
452                 return PTR_ERR(new_node);
453         }
454
455         tree->root = new_node->this;
456         if (!tree->depth) {
457                 tree->leaf_head = tree->leaf_tail = new_node->this;
458                 new_node->type = HFS_NODE_LEAF;
459                 new_node->num_recs = 0;
460         } else {
461                 new_node->type = HFS_NODE_INDEX;
462                 new_node->num_recs = 1;
463         }
464         new_node->parent = 0;
465         new_node->next = 0;
466         new_node->prev = 0;
467         new_node->height = ++tree->depth;
468
469         node_desc.next = cpu_to_be32(new_node->next);
470         node_desc.prev = cpu_to_be32(new_node->prev);
471         node_desc.type = new_node->type;
472         node_desc.height = new_node->height;
473         node_desc.num_recs = cpu_to_be16(new_node->num_recs);
474         node_desc.reserved = 0;
475         hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
476
477         rec = tree->node_size - 2;
478         hfs_bnode_write_u16(new_node, rec, 14);
479
480         if (node) {
481                 /* insert old root idx into new root */
482                 node->parent = tree->root;
483                 if (node->type == HFS_NODE_LEAF ||
484                     tree->attributes & HFS_TREE_VARIDXKEYS)
485                         key_size = hfs_bnode_read_u8(node, 14) + 1;
486                 else
487                         key_size = tree->max_key_len + 1;
488                 hfs_bnode_copy(new_node, 14, node, 14, key_size);
489
490                 if (!(tree->attributes & HFS_TREE_VARIDXKEYS)) {
491                         key_size = tree->max_key_len + 1;
492                         hfs_bnode_write_u8(new_node, 14, tree->max_key_len);
493                 }
494                 key_size = (key_size + 1) & -2;
495                 cnid = cpu_to_be32(node->this);
496                 hfs_bnode_write(new_node, &cnid, 14 + key_size, 4);
497
498                 rec -= 2;
499                 hfs_bnode_write_u16(new_node, rec, 14 + key_size + 4);
500
501                 hfs_bnode_put(node);
502         }
503         hfs_bnode_put(new_node);
504         mark_inode_dirty(tree->inode);
505
506         return 0;
507 }