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