Merge master.kernel.org:/pub/scm/linux/kernel/git/sam/kbuild
[linux-2.6] / fs / hfsplus / bnode.c
1 /*
2  *  linux/fs/hfsplus/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/string.h>
12 #include <linux/slab.h>
13 #include <linux/pagemap.h>
14 #include <linux/fs.h>
15 #include <linux/swap.h>
16 #include <linux/version.h>
17
18 #include "hfsplus_fs.h"
19 #include "hfsplus_raw.h"
20
21 #define REF_PAGES       0
22
23 /* Copy a specified range of bytes from the raw data of a node */
24 void hfs_bnode_read(struct hfs_bnode *node, void *buf, int off, int len)
25 {
26         struct page **pagep;
27         int l;
28
29         off += node->page_offset;
30         pagep = node->page + (off >> PAGE_CACHE_SHIFT);
31         off &= ~PAGE_CACHE_MASK;
32
33         l = min(len, (int)PAGE_CACHE_SIZE - off);
34         memcpy(buf, kmap(*pagep) + off, l);
35         kunmap(*pagep);
36
37         while ((len -= l) != 0) {
38                 buf += l;
39                 l = min(len, (int)PAGE_CACHE_SIZE);
40                 memcpy(buf, kmap(*++pagep), l);
41                 kunmap(*pagep);
42         }
43 }
44
45 u16 hfs_bnode_read_u16(struct hfs_bnode *node, int off)
46 {
47         __be16 data;
48         // optimize later...
49         hfs_bnode_read(node, &data, off, 2);
50         return be16_to_cpu(data);
51 }
52
53 u8 hfs_bnode_read_u8(struct hfs_bnode *node, int off)
54 {
55         u8 data;
56         // optimize later...
57         hfs_bnode_read(node, &data, off, 1);
58         return data;
59 }
60
61 void hfs_bnode_read_key(struct hfs_bnode *node, void *key, int off)
62 {
63         struct hfs_btree *tree;
64         int key_len;
65
66         tree = node->tree;
67         if (node->type == HFS_NODE_LEAF ||
68             tree->attributes & HFS_TREE_VARIDXKEYS)
69                 key_len = hfs_bnode_read_u16(node, off) + 2;
70         else
71                 key_len = tree->max_key_len + 2;
72
73         hfs_bnode_read(node, key, off, key_len);
74 }
75
76 void hfs_bnode_write(struct hfs_bnode *node, void *buf, int off, int len)
77 {
78         struct page **pagep;
79         int l;
80
81         off += node->page_offset;
82         pagep = node->page + (off >> PAGE_CACHE_SHIFT);
83         off &= ~PAGE_CACHE_MASK;
84
85         l = min(len, (int)PAGE_CACHE_SIZE - off);
86         memcpy(kmap(*pagep) + off, buf, l);
87         set_page_dirty(*pagep);
88         kunmap(*pagep);
89
90         while ((len -= l) != 0) {
91                 buf += l;
92                 l = min(len, (int)PAGE_CACHE_SIZE);
93                 memcpy(kmap(*++pagep), buf, l);
94                 set_page_dirty(*pagep);
95                 kunmap(*pagep);
96         }
97 }
98
99 void hfs_bnode_write_u16(struct hfs_bnode *node, int off, u16 data)
100 {
101         __be16 v = cpu_to_be16(data);
102         // optimize later...
103         hfs_bnode_write(node, &v, off, 2);
104 }
105
106 void hfs_bnode_clear(struct hfs_bnode *node, int off, int len)
107 {
108         struct page **pagep;
109         int l;
110
111         off += node->page_offset;
112         pagep = node->page + (off >> PAGE_CACHE_SHIFT);
113         off &= ~PAGE_CACHE_MASK;
114
115         l = min(len, (int)PAGE_CACHE_SIZE - off);
116         memset(kmap(*pagep) + off, 0, l);
117         set_page_dirty(*pagep);
118         kunmap(*pagep);
119
120         while ((len -= l) != 0) {
121                 l = min(len, (int)PAGE_CACHE_SIZE);
122                 memset(kmap(*++pagep), 0, l);
123                 set_page_dirty(*pagep);
124                 kunmap(*pagep);
125         }
126 }
127
128 void hfs_bnode_copy(struct hfs_bnode *dst_node, int dst,
129                     struct hfs_bnode *src_node, int src, int len)
130 {
131         struct hfs_btree *tree;
132         struct page **src_page, **dst_page;
133         int l;
134
135         dprint(DBG_BNODE_MOD, "copybytes: %u,%u,%u\n", dst, src, len);
136         if (!len)
137                 return;
138         tree = src_node->tree;
139         src += src_node->page_offset;
140         dst += dst_node->page_offset;
141         src_page = src_node->page + (src >> PAGE_CACHE_SHIFT);
142         src &= ~PAGE_CACHE_MASK;
143         dst_page = dst_node->page + (dst >> PAGE_CACHE_SHIFT);
144         dst &= ~PAGE_CACHE_MASK;
145
146         if (src == dst) {
147                 l = min(len, (int)PAGE_CACHE_SIZE - src);
148                 memcpy(kmap(*dst_page) + src, kmap(*src_page) + src, l);
149                 kunmap(*src_page);
150                 set_page_dirty(*dst_page);
151                 kunmap(*dst_page);
152
153                 while ((len -= l) != 0) {
154                         l = min(len, (int)PAGE_CACHE_SIZE);
155                         memcpy(kmap(*++dst_page), kmap(*++src_page), l);
156                         kunmap(*src_page);
157                         set_page_dirty(*dst_page);
158                         kunmap(*dst_page);
159                 }
160         } else {
161                 void *src_ptr, *dst_ptr;
162
163                 do {
164                         src_ptr = kmap(*src_page) + src;
165                         dst_ptr = kmap(*dst_page) + dst;
166                         if (PAGE_CACHE_SIZE - src < PAGE_CACHE_SIZE - dst) {
167                                 l = PAGE_CACHE_SIZE - src;
168                                 src = 0;
169                                 dst += l;
170                         } else {
171                                 l = PAGE_CACHE_SIZE - dst;
172                                 src += l;
173                                 dst = 0;
174                         }
175                         l = min(len, l);
176                         memcpy(dst_ptr, src_ptr, l);
177                         kunmap(*src_page);
178                         set_page_dirty(*dst_page);
179                         kunmap(*dst_page);
180                         if (!dst)
181                                 dst_page++;
182                         else
183                                 src_page++;
184                 } while ((len -= l));
185         }
186 }
187
188 void hfs_bnode_move(struct hfs_bnode *node, int dst, int src, int len)
189 {
190         struct page **src_page, **dst_page;
191         int l;
192
193         dprint(DBG_BNODE_MOD, "movebytes: %u,%u,%u\n", dst, src, len);
194         if (!len)
195                 return;
196         src += node->page_offset;
197         dst += node->page_offset;
198         if (dst > src) {
199                 src += len - 1;
200                 src_page = node->page + (src >> PAGE_CACHE_SHIFT);
201                 src = (src & ~PAGE_CACHE_MASK) + 1;
202                 dst += len - 1;
203                 dst_page = node->page + (dst >> PAGE_CACHE_SHIFT);
204                 dst = (dst & ~PAGE_CACHE_MASK) + 1;
205
206                 if (src == dst) {
207                         while (src < len) {
208                                 memmove(kmap(*dst_page), kmap(*src_page), src);
209                                 kunmap(*src_page);
210                                 set_page_dirty(*dst_page);
211                                 kunmap(*dst_page);
212                                 len -= src;
213                                 src = PAGE_CACHE_SIZE;
214                                 src_page--;
215                                 dst_page--;
216                         }
217                         src -= len;
218                         memmove(kmap(*dst_page) + src, kmap(*src_page) + src, len);
219                         kunmap(*src_page);
220                         set_page_dirty(*dst_page);
221                         kunmap(*dst_page);
222                 } else {
223                         void *src_ptr, *dst_ptr;
224
225                         do {
226                                 src_ptr = kmap(*src_page) + src;
227                                 dst_ptr = kmap(*dst_page) + dst;
228                                 if (src < dst) {
229                                         l = src;
230                                         src = PAGE_CACHE_SIZE;
231                                         dst -= l;
232                                 } else {
233                                         l = dst;
234                                         src -= l;
235                                         dst = PAGE_CACHE_SIZE;
236                                 }
237                                 l = min(len, l);
238                                 memmove(dst_ptr - l, src_ptr - l, l);
239                                 kunmap(*src_page);
240                                 set_page_dirty(*dst_page);
241                                 kunmap(*dst_page);
242                                 if (dst == PAGE_CACHE_SIZE)
243                                         dst_page--;
244                                 else
245                                         src_page--;
246                         } while ((len -= l));
247                 }
248         } else {
249                 src_page = node->page + (src >> PAGE_CACHE_SHIFT);
250                 src &= ~PAGE_CACHE_MASK;
251                 dst_page = node->page + (dst >> PAGE_CACHE_SHIFT);
252                 dst &= ~PAGE_CACHE_MASK;
253
254                 if (src == dst) {
255                         l = min(len, (int)PAGE_CACHE_SIZE - src);
256                         memmove(kmap(*dst_page) + src, kmap(*src_page) + src, l);
257                         kunmap(*src_page);
258                         set_page_dirty(*dst_page);
259                         kunmap(*dst_page);
260
261                         while ((len -= l) != 0) {
262                                 l = min(len, (int)PAGE_CACHE_SIZE);
263                                 memmove(kmap(*++dst_page), kmap(*++src_page), l);
264                                 kunmap(*src_page);
265                                 set_page_dirty(*dst_page);
266                                 kunmap(*dst_page);
267                         }
268                 } else {
269                         void *src_ptr, *dst_ptr;
270
271                         do {
272                                 src_ptr = kmap(*src_page) + src;
273                                 dst_ptr = kmap(*dst_page) + dst;
274                                 if (PAGE_CACHE_SIZE - src < PAGE_CACHE_SIZE - dst) {
275                                         l = PAGE_CACHE_SIZE - src;
276                                         src = 0;
277                                         dst += l;
278                                 } else {
279                                         l = PAGE_CACHE_SIZE - dst;
280                                         src += l;
281                                         dst = 0;
282                                 }
283                                 l = min(len, l);
284                                 memmove(dst_ptr, src_ptr, l);
285                                 kunmap(*src_page);
286                                 set_page_dirty(*dst_page);
287                                 kunmap(*dst_page);
288                                 if (!dst)
289                                         dst_page++;
290                                 else
291                                         src_page++;
292                         } while ((len -= l));
293                 }
294         }
295 }
296
297 void hfs_bnode_dump(struct hfs_bnode *node)
298 {
299         struct hfs_bnode_desc desc;
300         __be32 cnid;
301         int i, off, key_off;
302
303         dprint(DBG_BNODE_MOD, "bnode: %d\n", node->this);
304         hfs_bnode_read(node, &desc, 0, sizeof(desc));
305         dprint(DBG_BNODE_MOD, "%d, %d, %d, %d, %d\n",
306                 be32_to_cpu(desc.next), be32_to_cpu(desc.prev),
307                 desc.type, desc.height, be16_to_cpu(desc.num_recs));
308
309         off = node->tree->node_size - 2;
310         for (i = be16_to_cpu(desc.num_recs); i >= 0; off -= 2, i--) {
311                 key_off = hfs_bnode_read_u16(node, off);
312                 dprint(DBG_BNODE_MOD, " %d", key_off);
313                 if (i && node->type == HFS_NODE_INDEX) {
314                         int tmp;
315
316                         if (node->tree->attributes & HFS_TREE_VARIDXKEYS)
317                                 tmp = hfs_bnode_read_u16(node, key_off) + 2;
318                         else
319                                 tmp = node->tree->max_key_len + 2;
320                         dprint(DBG_BNODE_MOD, " (%d", tmp);
321                         hfs_bnode_read(node, &cnid, key_off + tmp, 4);
322                         dprint(DBG_BNODE_MOD, ",%d)", be32_to_cpu(cnid));
323                 } else if (i && node->type == HFS_NODE_LEAF) {
324                         int tmp;
325
326                         tmp = hfs_bnode_read_u16(node, key_off);
327                         dprint(DBG_BNODE_MOD, " (%d)", tmp);
328                 }
329         }
330         dprint(DBG_BNODE_MOD, "\n");
331 }
332
333 void hfs_bnode_unlink(struct hfs_bnode *node)
334 {
335         struct hfs_btree *tree;
336         struct hfs_bnode *tmp;
337         __be32 cnid;
338
339         tree = node->tree;
340         if (node->prev) {
341                 tmp = hfs_bnode_find(tree, node->prev);
342                 if (IS_ERR(tmp))
343                         return;
344                 tmp->next = node->next;
345                 cnid = cpu_to_be32(tmp->next);
346                 hfs_bnode_write(tmp, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
347                 hfs_bnode_put(tmp);
348         } else if (node->type == HFS_NODE_LEAF)
349                 tree->leaf_head = node->next;
350
351         if (node->next) {
352                 tmp = hfs_bnode_find(tree, node->next);
353                 if (IS_ERR(tmp))
354                         return;
355                 tmp->prev = node->prev;
356                 cnid = cpu_to_be32(tmp->prev);
357                 hfs_bnode_write(tmp, &cnid, offsetof(struct hfs_bnode_desc, prev), 4);
358                 hfs_bnode_put(tmp);
359         } else if (node->type == HFS_NODE_LEAF)
360                 tree->leaf_tail = node->prev;
361
362         // move down?
363         if (!node->prev && !node->next) {
364                 printk("hfs_btree_del_level\n");
365         }
366         if (!node->parent) {
367                 tree->root = 0;
368                 tree->depth = 0;
369         }
370         set_bit(HFS_BNODE_DELETED, &node->flags);
371 }
372
373 static inline int hfs_bnode_hash(u32 num)
374 {
375         num = (num >> 16) + num;
376         num += num >> 8;
377         return num & (NODE_HASH_SIZE - 1);
378 }
379
380 struct hfs_bnode *hfs_bnode_findhash(struct hfs_btree *tree, u32 cnid)
381 {
382         struct hfs_bnode *node;
383
384         if (cnid >= tree->node_count) {
385                 printk("HFS+-fs: request for non-existent node %d in B*Tree\n", cnid);
386                 return NULL;
387         }
388
389         for (node = tree->node_hash[hfs_bnode_hash(cnid)];
390              node; node = node->next_hash) {
391                 if (node->this == cnid) {
392                         return node;
393                 }
394         }
395         return NULL;
396 }
397
398 static struct hfs_bnode *__hfs_bnode_create(struct hfs_btree *tree, u32 cnid)
399 {
400         struct super_block *sb;
401         struct hfs_bnode *node, *node2;
402         struct address_space *mapping;
403         struct page *page;
404         int size, block, i, hash;
405         loff_t off;
406
407         if (cnid >= tree->node_count) {
408                 printk("HFS+-fs: request for non-existent node %d in B*Tree\n", cnid);
409                 return NULL;
410         }
411
412         sb = tree->inode->i_sb;
413         size = sizeof(struct hfs_bnode) + tree->pages_per_bnode *
414                 sizeof(struct page *);
415         node = kmalloc(size, GFP_KERNEL);
416         if (!node)
417                 return NULL;
418         memset(node, 0, size);
419         node->tree = tree;
420         node->this = cnid;
421         set_bit(HFS_BNODE_NEW, &node->flags);
422         atomic_set(&node->refcnt, 1);
423         dprint(DBG_BNODE_REFS, "new_node(%d:%d): 1\n",
424                node->tree->cnid, node->this);
425         init_waitqueue_head(&node->lock_wq);
426         spin_lock(&tree->hash_lock);
427         node2 = hfs_bnode_findhash(tree, cnid);
428         if (!node2) {
429                 hash = hfs_bnode_hash(cnid);
430                 node->next_hash = tree->node_hash[hash];
431                 tree->node_hash[hash] = node;
432                 tree->node_hash_cnt++;
433         } else {
434                 spin_unlock(&tree->hash_lock);
435                 kfree(node);
436                 wait_event(node2->lock_wq, !test_bit(HFS_BNODE_NEW, &node2->flags));
437                 return node2;
438         }
439         spin_unlock(&tree->hash_lock);
440
441         mapping = tree->inode->i_mapping;
442         off = (loff_t)cnid << tree->node_size_shift;
443         block = off >> PAGE_CACHE_SHIFT;
444         node->page_offset = off & ~PAGE_CACHE_MASK;
445         for (i = 0; i < tree->pages_per_bnode; block++, i++) {
446                 page = read_cache_page(mapping, block, (filler_t *)mapping->a_ops->readpage, NULL);
447                 if (IS_ERR(page))
448                         goto fail;
449                 if (PageError(page)) {
450                         page_cache_release(page);
451                         goto fail;
452                 }
453 #if !REF_PAGES
454                 page_cache_release(page);
455 #endif
456                 node->page[i] = page;
457         }
458
459         return node;
460 fail:
461         set_bit(HFS_BNODE_ERROR, &node->flags);
462         return node;
463 }
464
465 void hfs_bnode_unhash(struct hfs_bnode *node)
466 {
467         struct hfs_bnode **p;
468
469         dprint(DBG_BNODE_REFS, "remove_node(%d:%d): %d\n",
470                 node->tree->cnid, node->this, atomic_read(&node->refcnt));
471         for (p = &node->tree->node_hash[hfs_bnode_hash(node->this)];
472              *p && *p != node; p = &(*p)->next_hash)
473                 ;
474         if (!*p)
475                 BUG();
476         *p = node->next_hash;
477         node->tree->node_hash_cnt--;
478 }
479
480 /* Load a particular node out of a tree */
481 struct hfs_bnode *hfs_bnode_find(struct hfs_btree *tree, u32 num)
482 {
483         struct hfs_bnode *node;
484         struct hfs_bnode_desc *desc;
485         int i, rec_off, off, next_off;
486         int entry_size, key_size;
487
488         spin_lock(&tree->hash_lock);
489         node = hfs_bnode_findhash(tree, num);
490         if (node) {
491                 hfs_bnode_get(node);
492                 spin_unlock(&tree->hash_lock);
493                 wait_event(node->lock_wq, !test_bit(HFS_BNODE_NEW, &node->flags));
494                 if (test_bit(HFS_BNODE_ERROR, &node->flags))
495                         goto node_error;
496                 return node;
497         }
498         spin_unlock(&tree->hash_lock);
499         node = __hfs_bnode_create(tree, num);
500         if (!node)
501                 return ERR_PTR(-ENOMEM);
502         if (test_bit(HFS_BNODE_ERROR, &node->flags))
503                 goto node_error;
504         if (!test_bit(HFS_BNODE_NEW, &node->flags))
505                 return node;
506
507         desc = (struct hfs_bnode_desc *)(kmap(node->page[0]) + node->page_offset);
508         node->prev = be32_to_cpu(desc->prev);
509         node->next = be32_to_cpu(desc->next);
510         node->num_recs = be16_to_cpu(desc->num_recs);
511         node->type = desc->type;
512         node->height = desc->height;
513         kunmap(node->page[0]);
514
515         switch (node->type) {
516         case HFS_NODE_HEADER:
517         case HFS_NODE_MAP:
518                 if (node->height != 0)
519                         goto node_error;
520                 break;
521         case HFS_NODE_LEAF:
522                 if (node->height != 1)
523                         goto node_error;
524                 break;
525         case HFS_NODE_INDEX:
526                 if (node->height <= 1 || node->height > tree->depth)
527                         goto node_error;
528                 break;
529         default:
530                 goto node_error;
531         }
532
533         rec_off = tree->node_size - 2;
534         off = hfs_bnode_read_u16(node, rec_off);
535         if (off != sizeof(struct hfs_bnode_desc))
536                 goto node_error;
537         for (i = 1; i <= node->num_recs; off = next_off, i++) {
538                 rec_off -= 2;
539                 next_off = hfs_bnode_read_u16(node, rec_off);
540                 if (next_off <= off ||
541                     next_off > tree->node_size ||
542                     next_off & 1)
543                         goto node_error;
544                 entry_size = next_off - off;
545                 if (node->type != HFS_NODE_INDEX &&
546                     node->type != HFS_NODE_LEAF)
547                         continue;
548                 key_size = hfs_bnode_read_u16(node, off) + 2;
549                 if (key_size >= entry_size || key_size & 1)
550                         goto node_error;
551         }
552         clear_bit(HFS_BNODE_NEW, &node->flags);
553         wake_up(&node->lock_wq);
554         return node;
555
556 node_error:
557         set_bit(HFS_BNODE_ERROR, &node->flags);
558         clear_bit(HFS_BNODE_NEW, &node->flags);
559         wake_up(&node->lock_wq);
560         hfs_bnode_put(node);
561         return ERR_PTR(-EIO);
562 }
563
564 void hfs_bnode_free(struct hfs_bnode *node)
565 {
566         //int i;
567
568         //for (i = 0; i < node->tree->pages_per_bnode; i++)
569         //      if (node->page[i])
570         //              page_cache_release(node->page[i]);
571         kfree(node);
572 }
573
574 struct hfs_bnode *hfs_bnode_create(struct hfs_btree *tree, u32 num)
575 {
576         struct hfs_bnode *node;
577         struct page **pagep;
578         int i;
579
580         spin_lock(&tree->hash_lock);
581         node = hfs_bnode_findhash(tree, num);
582         spin_unlock(&tree->hash_lock);
583         if (node) {
584                 printk("new node %u already hashed?\n", num);
585                 BUG();
586         }
587         node = __hfs_bnode_create(tree, num);
588         if (!node)
589                 return ERR_PTR(-ENOMEM);
590         if (test_bit(HFS_BNODE_ERROR, &node->flags)) {
591                 hfs_bnode_put(node);
592                 return ERR_PTR(-EIO);
593         }
594
595         pagep = node->page;
596         memset(kmap(*pagep) + node->page_offset, 0,
597                min((int)PAGE_CACHE_SIZE, (int)tree->node_size));
598         set_page_dirty(*pagep);
599         kunmap(*pagep);
600         for (i = 1; i < tree->pages_per_bnode; i++) {
601                 memset(kmap(*++pagep), 0, PAGE_CACHE_SIZE);
602                 set_page_dirty(*pagep);
603                 kunmap(*pagep);
604         }
605         clear_bit(HFS_BNODE_NEW, &node->flags);
606         wake_up(&node->lock_wq);
607
608         return node;
609 }
610
611 void hfs_bnode_get(struct hfs_bnode *node)
612 {
613         if (node) {
614                 atomic_inc(&node->refcnt);
615 #if REF_PAGES
616                 {
617                 int i;
618                 for (i = 0; i < node->tree->pages_per_bnode; i++)
619                         get_page(node->page[i]);
620                 }
621 #endif
622                 dprint(DBG_BNODE_REFS, "get_node(%d:%d): %d\n",
623                        node->tree->cnid, node->this, atomic_read(&node->refcnt));
624         }
625 }
626
627 /* Dispose of resources used by a node */
628 void hfs_bnode_put(struct hfs_bnode *node)
629 {
630         if (node) {
631                 struct hfs_btree *tree = node->tree;
632                 int i;
633
634                 dprint(DBG_BNODE_REFS, "put_node(%d:%d): %d\n",
635                        node->tree->cnid, node->this, atomic_read(&node->refcnt));
636                 if (!atomic_read(&node->refcnt))
637                         BUG();
638                 if (!atomic_dec_and_lock(&node->refcnt, &tree->hash_lock)) {
639 #if REF_PAGES
640                         for (i = 0; i < tree->pages_per_bnode; i++)
641                                 put_page(node->page[i]);
642 #endif
643                         return;
644                 }
645                 for (i = 0; i < tree->pages_per_bnode; i++) {
646                         if (!node->page[i])
647                                 continue;
648                         mark_page_accessed(node->page[i]);
649 #if REF_PAGES
650                         put_page(node->page[i]);
651 #endif
652                 }
653
654                 if (test_bit(HFS_BNODE_DELETED, &node->flags)) {
655                         hfs_bnode_unhash(node);
656                         spin_unlock(&tree->hash_lock);
657                         hfs_bmap_free(node);
658                         hfs_bnode_free(node);
659                         return;
660                 }
661                 spin_unlock(&tree->hash_lock);
662         }
663 }
664