Linux-2.6.12-rc2
[linux-2.6.git] / fs / hfs / bnode.c
1 /*
2  *  linux/fs/hfs/bnode.c
3  *
4  * Copyright (C) 2001
5  * Brad Boyer (flar@allandria.com)
6  * (C) 2003 Ardis Technologies <roman@ardistech.com>
7  *
8  * Handle basic btree node operations
9  */
10
11 #include <linux/pagemap.h>
12 #include <linux/swap.h>
13
14 #include "btree.h"
15
16 #define REF_PAGES       0
17
18 void hfs_bnode_read(struct hfs_bnode *node, void *buf,
19                 int off, int len)
20 {
21         struct page *page;
22
23         off += node->page_offset;
24         page = node->page[0];
25
26         memcpy(buf, kmap(page) + off, len);
27         kunmap(page);
28 }
29
30 u16 hfs_bnode_read_u16(struct hfs_bnode *node, int off)
31 {
32         __be16 data;
33         // optimize later...
34         hfs_bnode_read(node, &data, off, 2);
35         return be16_to_cpu(data);
36 }
37
38 u8 hfs_bnode_read_u8(struct hfs_bnode *node, int off)
39 {
40         u8 data;
41         // optimize later...
42         hfs_bnode_read(node, &data, off, 1);
43         return data;
44 }
45
46 void hfs_bnode_read_key(struct hfs_bnode *node, void *key, int off)
47 {
48         struct hfs_btree *tree;
49         int key_len;
50
51         tree = node->tree;
52         if (node->type == HFS_NODE_LEAF ||
53             tree->attributes & HFS_TREE_VARIDXKEYS)
54                 key_len = hfs_bnode_read_u8(node, off) + 1;
55         else
56                 key_len = tree->max_key_len + 1;
57
58         hfs_bnode_read(node, key, off, key_len);
59 }
60
61 void hfs_bnode_write(struct hfs_bnode *node, void *buf, int off, int len)
62 {
63         struct page *page;
64
65         off += node->page_offset;
66         page = node->page[0];
67
68         memcpy(kmap(page) + off, buf, len);
69         kunmap(page);
70         set_page_dirty(page);
71 }
72
73 void hfs_bnode_write_u16(struct hfs_bnode *node, int off, u16 data)
74 {
75         __be16 v = cpu_to_be16(data);
76         // optimize later...
77         hfs_bnode_write(node, &v, off, 2);
78 }
79
80 void hfs_bnode_write_u8(struct hfs_bnode *node, int off, u8 data)
81 {
82         // optimize later...
83         hfs_bnode_write(node, &data, off, 1);
84 }
85
86 void hfs_bnode_clear(struct hfs_bnode *node, int off, int len)
87 {
88         struct page *page;
89
90         off += node->page_offset;
91         page = node->page[0];
92
93         memset(kmap(page) + off, 0, len);
94         kunmap(page);
95         set_page_dirty(page);
96 }
97
98 void hfs_bnode_copy(struct hfs_bnode *dst_node, int dst,
99                 struct hfs_bnode *src_node, int src, int len)
100 {
101         struct hfs_btree *tree;
102         struct page *src_page, *dst_page;
103
104         dprint(DBG_BNODE_MOD, "copybytes: %u,%u,%u\n", dst, src, len);
105         if (!len)
106                 return;
107         tree = src_node->tree;
108         src += src_node->page_offset;
109         dst += dst_node->page_offset;
110         src_page = src_node->page[0];
111         dst_page = dst_node->page[0];
112
113         memcpy(kmap(dst_page) + dst, kmap(src_page) + src, len);
114         kunmap(src_page);
115         kunmap(dst_page);
116         set_page_dirty(dst_page);
117 }
118
119 void hfs_bnode_move(struct hfs_bnode *node, int dst, int src, int len)
120 {
121         struct page *page;
122         void *ptr;
123
124         dprint(DBG_BNODE_MOD, "movebytes: %u,%u,%u\n", dst, src, len);
125         if (!len)
126                 return;
127         src += node->page_offset;
128         dst += node->page_offset;
129         page = node->page[0];
130         ptr = kmap(page);
131         memmove(ptr + dst, ptr + src, len);
132         kunmap(page);
133         set_page_dirty(page);
134 }
135
136 void hfs_bnode_dump(struct hfs_bnode *node)
137 {
138         struct hfs_bnode_desc desc;
139         __be32 cnid;
140         int i, off, key_off;
141
142         dprint(DBG_BNODE_MOD, "bnode: %d\n", node->this);
143         hfs_bnode_read(node, &desc, 0, sizeof(desc));
144         dprint(DBG_BNODE_MOD, "%d, %d, %d, %d, %d\n",
145                 be32_to_cpu(desc.next), be32_to_cpu(desc.prev),
146                 desc.type, desc.height, be16_to_cpu(desc.num_recs));
147
148         off = node->tree->node_size - 2;
149         for (i = be16_to_cpu(desc.num_recs); i >= 0; off -= 2, i--) {
150                 key_off = hfs_bnode_read_u16(node, off);
151                 dprint(DBG_BNODE_MOD, " %d", key_off);
152                 if (i && node->type == HFS_NODE_INDEX) {
153                         int tmp;
154
155                         if (node->tree->attributes & HFS_TREE_VARIDXKEYS)
156                                 tmp = (hfs_bnode_read_u8(node, key_off) | 1) + 1;
157                         else
158                                 tmp = node->tree->max_key_len + 1;
159                         dprint(DBG_BNODE_MOD, " (%d,%d", tmp, hfs_bnode_read_u8(node, key_off));
160                         hfs_bnode_read(node, &cnid, key_off + tmp, 4);
161                         dprint(DBG_BNODE_MOD, ",%d)", be32_to_cpu(cnid));
162                 } else if (i && node->type == HFS_NODE_LEAF) {
163                         int tmp;
164
165                         tmp = hfs_bnode_read_u8(node, key_off);
166                         dprint(DBG_BNODE_MOD, " (%d)", tmp);
167                 }
168         }
169         dprint(DBG_BNODE_MOD, "\n");
170 }
171
172 void hfs_bnode_unlink(struct hfs_bnode *node)
173 {
174         struct hfs_btree *tree;
175         struct hfs_bnode *tmp;
176         __be32 cnid;
177
178         tree = node->tree;
179         if (node->prev) {
180                 tmp = hfs_bnode_find(tree, node->prev);
181                 if (IS_ERR(tmp))
182                         return;
183                 tmp->next = node->next;
184                 cnid = cpu_to_be32(tmp->next);
185                 hfs_bnode_write(tmp, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
186                 hfs_bnode_put(tmp);
187         } else if (node->type == HFS_NODE_LEAF)
188                 tree->leaf_head = node->next;
189
190         if (node->next) {
191                 tmp = hfs_bnode_find(tree, node->next);
192                 if (IS_ERR(tmp))
193                         return;
194                 tmp->prev = node->prev;
195                 cnid = cpu_to_be32(tmp->prev);
196                 hfs_bnode_write(tmp, &cnid, offsetof(struct hfs_bnode_desc, prev), 4);
197                 hfs_bnode_put(tmp);
198         } else if (node->type == HFS_NODE_LEAF)
199                 tree->leaf_tail = node->prev;
200
201         // move down?
202         if (!node->prev && !node->next) {
203                 printk("hfs_btree_del_level\n");
204         }
205         if (!node->parent) {
206                 tree->root = 0;
207                 tree->depth = 0;
208         }
209         set_bit(HFS_BNODE_DELETED, &node->flags);
210 }
211
212 static inline int hfs_bnode_hash(u32 num)
213 {
214         num = (num >> 16) + num;
215         num += num >> 8;
216         return num & (NODE_HASH_SIZE - 1);
217 }
218
219 struct hfs_bnode *hfs_bnode_findhash(struct hfs_btree *tree, u32 cnid)
220 {
221         struct hfs_bnode *node;
222
223         if (cnid >= tree->node_count) {
224                 printk("HFS: request for non-existent node %d in B*Tree\n", cnid);
225                 return NULL;
226         }
227
228         for (node = tree->node_hash[hfs_bnode_hash(cnid)];
229              node; node = node->next_hash) {
230                 if (node->this == cnid) {
231                         return node;
232                 }
233         }
234         return NULL;
235 }
236
237 static struct hfs_bnode *__hfs_bnode_create(struct hfs_btree *tree, u32 cnid)
238 {
239         struct super_block *sb;
240         struct hfs_bnode *node, *node2;
241         struct address_space *mapping;
242         struct page *page;
243         int size, block, i, hash;
244         loff_t off;
245
246         if (cnid >= tree->node_count) {
247                 printk("HFS: request for non-existent node %d in B*Tree\n", cnid);
248                 return NULL;
249         }
250
251         sb = tree->inode->i_sb;
252         size = sizeof(struct hfs_bnode) + tree->pages_per_bnode *
253                 sizeof(struct page *);
254         node = kmalloc(size, GFP_KERNEL);
255         if (!node)
256                 return NULL;
257         memset(node, 0, size);
258         node->tree = tree;
259         node->this = cnid;
260         set_bit(HFS_BNODE_NEW, &node->flags);
261         atomic_set(&node->refcnt, 1);
262         dprint(DBG_BNODE_REFS, "new_node(%d:%d): 1\n",
263                node->tree->cnid, node->this);
264         init_waitqueue_head(&node->lock_wq);
265         spin_lock(&tree->hash_lock);
266         node2 = hfs_bnode_findhash(tree, cnid);
267         if (!node2) {
268                 hash = hfs_bnode_hash(cnid);
269                 node->next_hash = tree->node_hash[hash];
270                 tree->node_hash[hash] = node;
271                 tree->node_hash_cnt++;
272         } else {
273                 spin_unlock(&tree->hash_lock);
274                 kfree(node);
275                 wait_event(node2->lock_wq, !test_bit(HFS_BNODE_NEW, &node2->flags));
276                 return node2;
277         }
278         spin_unlock(&tree->hash_lock);
279
280         mapping = tree->inode->i_mapping;
281         off = (loff_t)cnid * tree->node_size;
282         block = off >> PAGE_CACHE_SHIFT;
283         node->page_offset = off & ~PAGE_CACHE_MASK;
284         for (i = 0; i < tree->pages_per_bnode; i++) {
285                 page = read_cache_page(mapping, block++, (filler_t *)mapping->a_ops->readpage, NULL);
286                 if (IS_ERR(page))
287                         goto fail;
288                 if (PageError(page)) {
289                         page_cache_release(page);
290                         goto fail;
291                 }
292 #if !REF_PAGES
293                 page_cache_release(page);
294 #endif
295                 node->page[i] = page;
296         }
297
298         return node;
299 fail:
300         set_bit(HFS_BNODE_ERROR, &node->flags);
301         return node;
302 }
303
304 void hfs_bnode_unhash(struct hfs_bnode *node)
305 {
306         struct hfs_bnode **p;
307
308         dprint(DBG_BNODE_REFS, "remove_node(%d:%d): %d\n",
309                 node->tree->cnid, node->this, atomic_read(&node->refcnt));
310         for (p = &node->tree->node_hash[hfs_bnode_hash(node->this)];
311              *p && *p != node; p = &(*p)->next_hash)
312                 ;
313         if (!*p)
314                 BUG();
315         *p = node->next_hash;
316         node->tree->node_hash_cnt--;
317 }
318
319 /* Load a particular node out of a tree */
320 struct hfs_bnode *hfs_bnode_find(struct hfs_btree *tree, u32 num)
321 {
322         struct hfs_bnode *node;
323         struct hfs_bnode_desc *desc;
324         int i, rec_off, off, next_off;
325         int entry_size, key_size;
326
327         spin_lock(&tree->hash_lock);
328         node = hfs_bnode_findhash(tree, num);
329         if (node) {
330                 hfs_bnode_get(node);
331                 spin_unlock(&tree->hash_lock);
332                 wait_event(node->lock_wq, !test_bit(HFS_BNODE_NEW, &node->flags));
333                 if (test_bit(HFS_BNODE_ERROR, &node->flags))
334                         goto node_error;
335                 return node;
336         }
337         spin_unlock(&tree->hash_lock);
338         node = __hfs_bnode_create(tree, num);
339         if (!node)
340                 return ERR_PTR(-ENOMEM);
341         if (test_bit(HFS_BNODE_ERROR, &node->flags))
342                 goto node_error;
343         if (!test_bit(HFS_BNODE_NEW, &node->flags))
344                 return node;
345
346         desc = (struct hfs_bnode_desc *)(kmap(node->page[0]) + node->page_offset);
347         node->prev = be32_to_cpu(desc->prev);
348         node->next = be32_to_cpu(desc->next);
349         node->num_recs = be16_to_cpu(desc->num_recs);
350         node->type = desc->type;
351         node->height = desc->height;
352         kunmap(node->page[0]);
353
354         switch (node->type) {
355         case HFS_NODE_HEADER:
356         case HFS_NODE_MAP:
357                 if (node->height != 0)
358                         goto node_error;
359                 break;
360         case HFS_NODE_LEAF:
361                 if (node->height != 1)
362                         goto node_error;
363                 break;
364         case HFS_NODE_INDEX:
365                 if (node->height <= 1 || node->height > tree->depth)
366                         goto node_error;
367                 break;
368         default:
369                 goto node_error;
370         }
371
372         rec_off = tree->node_size - 2;
373         off = hfs_bnode_read_u16(node, rec_off);
374         if (off != sizeof(struct hfs_bnode_desc))
375                 goto node_error;
376         for (i = 1; i <= node->num_recs; off = next_off, i++) {
377                 rec_off -= 2;
378                 next_off = hfs_bnode_read_u16(node, rec_off);
379                 if (next_off <= off ||
380                     next_off > tree->node_size ||
381                     next_off & 1)
382                         goto node_error;
383                 entry_size = next_off - off;
384                 if (node->type != HFS_NODE_INDEX &&
385                     node->type != HFS_NODE_LEAF)
386                         continue;
387                 key_size = hfs_bnode_read_u8(node, off) + 1;
388                 if (key_size >= entry_size /*|| key_size & 1*/)
389                         goto node_error;
390         }
391         clear_bit(HFS_BNODE_NEW, &node->flags);
392         wake_up(&node->lock_wq);
393         return node;
394
395 node_error:
396         set_bit(HFS_BNODE_ERROR, &node->flags);
397         clear_bit(HFS_BNODE_NEW, &node->flags);
398         wake_up(&node->lock_wq);
399         hfs_bnode_put(node);
400         return ERR_PTR(-EIO);
401 }
402
403 void hfs_bnode_free(struct hfs_bnode *node)
404 {
405         //int i;
406
407         //for (i = 0; i < node->tree->pages_per_bnode; i++)
408         //      if (node->page[i])
409         //              page_cache_release(node->page[i]);
410         kfree(node);
411 }
412
413 struct hfs_bnode *hfs_bnode_create(struct hfs_btree *tree, u32 num)
414 {
415         struct hfs_bnode *node;
416         struct page **pagep;
417         int i;
418
419         spin_lock(&tree->hash_lock);
420         node = hfs_bnode_findhash(tree, num);
421         spin_unlock(&tree->hash_lock);
422         if (node)
423                 BUG();
424         node = __hfs_bnode_create(tree, num);
425         if (!node)
426                 return ERR_PTR(-ENOMEM);
427         if (test_bit(HFS_BNODE_ERROR, &node->flags)) {
428                 hfs_bnode_put(node);
429                 return ERR_PTR(-EIO);
430         }
431
432         pagep = node->page;
433         memset(kmap(*pagep) + node->page_offset, 0,
434                min((int)PAGE_CACHE_SIZE, (int)tree->node_size));
435         set_page_dirty(*pagep);
436         kunmap(*pagep);
437         for (i = 1; i < tree->pages_per_bnode; i++) {
438                 memset(kmap(*++pagep), 0, PAGE_CACHE_SIZE);
439                 set_page_dirty(*pagep);
440                 kunmap(*pagep);
441         }
442         clear_bit(HFS_BNODE_NEW, &node->flags);
443         wake_up(&node->lock_wq);
444
445         return node;
446 }
447
448 void hfs_bnode_get(struct hfs_bnode *node)
449 {
450         if (node) {
451                 atomic_inc(&node->refcnt);
452 #if REF_PAGES
453                 {
454                 int i;
455                 for (i = 0; i < node->tree->pages_per_bnode; i++)
456                         get_page(node->page[i]);
457                 }
458 #endif
459                 dprint(DBG_BNODE_REFS, "get_node(%d:%d): %d\n",
460                        node->tree->cnid, node->this, atomic_read(&node->refcnt));
461         }
462 }
463
464 /* Dispose of resources used by a node */
465 void hfs_bnode_put(struct hfs_bnode *node)
466 {
467         if (node) {
468                 struct hfs_btree *tree = node->tree;
469                 int i;
470
471                 dprint(DBG_BNODE_REFS, "put_node(%d:%d): %d\n",
472                        node->tree->cnid, node->this, atomic_read(&node->refcnt));
473                 if (!atomic_read(&node->refcnt))
474                         BUG();
475                 if (!atomic_dec_and_lock(&node->refcnt, &tree->hash_lock)) {
476 #if REF_PAGES
477                         for (i = 0; i < tree->pages_per_bnode; i++)
478                                 put_page(node->page[i]);
479 #endif
480                         return;
481                 }
482                 for (i = 0; i < tree->pages_per_bnode; i++) {
483                         mark_page_accessed(node->page[i]);
484 #if REF_PAGES
485                         put_page(node->page[i]);
486 #endif
487                 }
488
489                 if (test_bit(HFS_BNODE_DELETED, &node->flags)) {
490                         hfs_bnode_unhash(node);
491                         spin_unlock(&tree->hash_lock);
492                         hfs_bmap_free(node);
493                         hfs_bnode_free(node);
494                         return;
495                 }
496                 spin_unlock(&tree->hash_lock);
497         }
498 }