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Linux/fs/hfs/bnode.c

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  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/slab.h>
 13 #include <linux/swap.h>
 14 
 15 #include "btree.h"
 16 
 17 void hfs_bnode_read(struct hfs_bnode *node, void *buf,
 18                 int off, int len)
 19 {
 20         struct page *page;
 21 
 22         off += node->page_offset;
 23         page = node->page[0];
 24 
 25         memcpy(buf, kmap(page) + off, len);
 26         kunmap(page);
 27 }
 28 
 29 u16 hfs_bnode_read_u16(struct hfs_bnode *node, int off)
 30 {
 31         __be16 data;
 32         // optimize later...
 33         hfs_bnode_read(node, &data, off, 2);
 34         return be16_to_cpu(data);
 35 }
 36 
 37 u8 hfs_bnode_read_u8(struct hfs_bnode *node, int off)
 38 {
 39         u8 data;
 40         // optimize later...
 41         hfs_bnode_read(node, &data, off, 1);
 42         return data;
 43 }
 44 
 45 void hfs_bnode_read_key(struct hfs_bnode *node, void *key, int off)
 46 {
 47         struct hfs_btree *tree;
 48         int key_len;
 49 
 50         tree = node->tree;
 51         if (node->type == HFS_NODE_LEAF ||
 52             tree->attributes & HFS_TREE_VARIDXKEYS)
 53                 key_len = hfs_bnode_read_u8(node, off) + 1;
 54         else
 55                 key_len = tree->max_key_len + 1;
 56 
 57         hfs_bnode_read(node, key, off, key_len);
 58 }
 59 
 60 void hfs_bnode_write(struct hfs_bnode *node, void *buf, int off, int len)
 61 {
 62         struct page *page;
 63 
 64         off += node->page_offset;
 65         page = node->page[0];
 66 
 67         memcpy(kmap(page) + off, buf, len);
 68         kunmap(page);
 69         set_page_dirty(page);
 70 }
 71 
 72 void hfs_bnode_write_u16(struct hfs_bnode *node, int off, u16 data)
 73 {
 74         __be16 v = cpu_to_be16(data);
 75         // optimize later...
 76         hfs_bnode_write(node, &v, off, 2);
 77 }
 78 
 79 void hfs_bnode_write_u8(struct hfs_bnode *node, int off, u8 data)
 80 {
 81         // optimize later...
 82         hfs_bnode_write(node, &data, off, 1);
 83 }
 84 
 85 void hfs_bnode_clear(struct hfs_bnode *node, int off, int len)
 86 {
 87         struct page *page;
 88 
 89         off += node->page_offset;
 90         page = node->page[0];
 91 
 92         memset(kmap(page) + off, 0, len);
 93         kunmap(page);
 94         set_page_dirty(page);
 95 }
 96 
 97 void hfs_bnode_copy(struct hfs_bnode *dst_node, int dst,
 98                 struct hfs_bnode *src_node, int src, int len)
 99 {
100         struct hfs_btree *tree;
101         struct page *src_page, *dst_page;
102 
103         hfs_dbg(BNODE_MOD, "copybytes: %u,%u,%u\n", dst, src, len);
104         if (!len)
105                 return;
106         tree = src_node->tree;
107         src += src_node->page_offset;
108         dst += dst_node->page_offset;
109         src_page = src_node->page[0];
110         dst_page = dst_node->page[0];
111 
112         memcpy(kmap(dst_page) + dst, kmap(src_page) + src, len);
113         kunmap(src_page);
114         kunmap(dst_page);
115         set_page_dirty(dst_page);
116 }
117 
118 void hfs_bnode_move(struct hfs_bnode *node, int dst, int src, int len)
119 {
120         struct page *page;
121         void *ptr;
122 
123         hfs_dbg(BNODE_MOD, "movebytes: %u,%u,%u\n", dst, src, len);
124         if (!len)
125                 return;
126         src += node->page_offset;
127         dst += node->page_offset;
128         page = node->page[0];
129         ptr = kmap(page);
130         memmove(ptr + dst, ptr + src, len);
131         kunmap(page);
132         set_page_dirty(page);
133 }
134 
135 void hfs_bnode_dump(struct hfs_bnode *node)
136 {
137         struct hfs_bnode_desc desc;
138         __be32 cnid;
139         int i, off, key_off;
140 
141         hfs_dbg(BNODE_MOD, "bnode: %d\n", node->this);
142         hfs_bnode_read(node, &desc, 0, sizeof(desc));
143         hfs_dbg(BNODE_MOD, "%d, %d, %d, %d, %d\n",
144                 be32_to_cpu(desc.next), be32_to_cpu(desc.prev),
145                 desc.type, desc.height, be16_to_cpu(desc.num_recs));
146 
147         off = node->tree->node_size - 2;
148         for (i = be16_to_cpu(desc.num_recs); i >= 0; off -= 2, i--) {
149                 key_off = hfs_bnode_read_u16(node, off);
150                 hfs_dbg_cont(BNODE_MOD, " %d", key_off);
151                 if (i && node->type == HFS_NODE_INDEX) {
152                         int tmp;
153 
154                         if (node->tree->attributes & HFS_TREE_VARIDXKEYS)
155                                 tmp = (hfs_bnode_read_u8(node, key_off) | 1) + 1;
156                         else
157                                 tmp = node->tree->max_key_len + 1;
158                         hfs_dbg_cont(BNODE_MOD, " (%d,%d",
159                                      tmp, hfs_bnode_read_u8(node, key_off));
160                         hfs_bnode_read(node, &cnid, key_off + tmp, 4);
161                         hfs_dbg_cont(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                         hfs_dbg_cont(BNODE_MOD, " (%d)", tmp);
167                 }
168         }
169         hfs_dbg_cont(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(KERN_DEBUG "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                 pr_err("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                 pr_err("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 = kzalloc(size, GFP_KERNEL);
255         if (!node)
256                 return NULL;
257         node->tree = tree;
258         node->this = cnid;
259         set_bit(HFS_BNODE_NEW, &node->flags);
260         atomic_set(&node->refcnt, 1);
261         hfs_dbg(BNODE_REFS, "new_node(%d:%d): 1\n",
262                 node->tree->cnid, node->this);
263         init_waitqueue_head(&node->lock_wq);
264         spin_lock(&tree->hash_lock);
265         node2 = hfs_bnode_findhash(tree, cnid);
266         if (!node2) {
267                 hash = hfs_bnode_hash(cnid);
268                 node->next_hash = tree->node_hash[hash];
269                 tree->node_hash[hash] = node;
270                 tree->node_hash_cnt++;
271         } else {
272                 spin_unlock(&tree->hash_lock);
273                 kfree(node);
274                 wait_event(node2->lock_wq, !test_bit(HFS_BNODE_NEW, &node2->flags));
275                 return node2;
276         }
277         spin_unlock(&tree->hash_lock);
278 
279         mapping = tree->inode->i_mapping;
280         off = (loff_t)cnid * tree->node_size;
281         block = off >> PAGE_CACHE_SHIFT;
282         node->page_offset = off & ~PAGE_CACHE_MASK;
283         for (i = 0; i < tree->pages_per_bnode; i++) {
284                 page = read_mapping_page(mapping, block++, NULL);
285                 if (IS_ERR(page))
286                         goto fail;
287                 if (PageError(page)) {
288                         page_cache_release(page);
289                         goto fail;
290                 }
291                 page_cache_release(page);
292                 node->page[i] = page;
293         }
294 
295         return node;
296 fail:
297         set_bit(HFS_BNODE_ERROR, &node->flags);
298         return node;
299 }
300 
301 void hfs_bnode_unhash(struct hfs_bnode *node)
302 {
303         struct hfs_bnode **p;
304 
305         hfs_dbg(BNODE_REFS, "remove_node(%d:%d): %d\n",
306                 node->tree->cnid, node->this, atomic_read(&node->refcnt));
307         for (p = &node->tree->node_hash[hfs_bnode_hash(node->this)];
308              *p && *p != node; p = &(*p)->next_hash)
309                 ;
310         BUG_ON(!*p);
311         *p = node->next_hash;
312         node->tree->node_hash_cnt--;
313 }
314 
315 /* Load a particular node out of a tree */
316 struct hfs_bnode *hfs_bnode_find(struct hfs_btree *tree, u32 num)
317 {
318         struct hfs_bnode *node;
319         struct hfs_bnode_desc *desc;
320         int i, rec_off, off, next_off;
321         int entry_size, key_size;
322 
323         spin_lock(&tree->hash_lock);
324         node = hfs_bnode_findhash(tree, num);
325         if (node) {
326                 hfs_bnode_get(node);
327                 spin_unlock(&tree->hash_lock);
328                 wait_event(node->lock_wq, !test_bit(HFS_BNODE_NEW, &node->flags));
329                 if (test_bit(HFS_BNODE_ERROR, &node->flags))
330                         goto node_error;
331                 return node;
332         }
333         spin_unlock(&tree->hash_lock);
334         node = __hfs_bnode_create(tree, num);
335         if (!node)
336                 return ERR_PTR(-ENOMEM);
337         if (test_bit(HFS_BNODE_ERROR, &node->flags))
338                 goto node_error;
339         if (!test_bit(HFS_BNODE_NEW, &node->flags))
340                 return node;
341 
342         desc = (struct hfs_bnode_desc *)(kmap(node->page[0]) + node->page_offset);
343         node->prev = be32_to_cpu(desc->prev);
344         node->next = be32_to_cpu(desc->next);
345         node->num_recs = be16_to_cpu(desc->num_recs);
346         node->type = desc->type;
347         node->height = desc->height;
348         kunmap(node->page[0]);
349 
350         switch (node->type) {
351         case HFS_NODE_HEADER:
352         case HFS_NODE_MAP:
353                 if (node->height != 0)
354                         goto node_error;
355                 break;
356         case HFS_NODE_LEAF:
357                 if (node->height != 1)
358                         goto node_error;
359                 break;
360         case HFS_NODE_INDEX:
361                 if (node->height <= 1 || node->height > tree->depth)
362                         goto node_error;
363                 break;
364         default:
365                 goto node_error;
366         }
367 
368         rec_off = tree->node_size - 2;
369         off = hfs_bnode_read_u16(node, rec_off);
370         if (off != sizeof(struct hfs_bnode_desc))
371                 goto node_error;
372         for (i = 1; i <= node->num_recs; off = next_off, i++) {
373                 rec_off -= 2;
374                 next_off = hfs_bnode_read_u16(node, rec_off);
375                 if (next_off <= off ||
376                     next_off > tree->node_size ||
377                     next_off & 1)
378                         goto node_error;
379                 entry_size = next_off - off;
380                 if (node->type != HFS_NODE_INDEX &&
381                     node->type != HFS_NODE_LEAF)
382                         continue;
383                 key_size = hfs_bnode_read_u8(node, off) + 1;
384                 if (key_size >= entry_size /*|| key_size & 1*/)
385                         goto node_error;
386         }
387         clear_bit(HFS_BNODE_NEW, &node->flags);
388         wake_up(&node->lock_wq);
389         return node;
390 
391 node_error:
392         set_bit(HFS_BNODE_ERROR, &node->flags);
393         clear_bit(HFS_BNODE_NEW, &node->flags);
394         wake_up(&node->lock_wq);
395         hfs_bnode_put(node);
396         return ERR_PTR(-EIO);
397 }
398 
399 void hfs_bnode_free(struct hfs_bnode *node)
400 {
401         //int i;
402 
403         //for (i = 0; i < node->tree->pages_per_bnode; i++)
404         //      if (node->page[i])
405         //              page_cache_release(node->page[i]);
406         kfree(node);
407 }
408 
409 struct hfs_bnode *hfs_bnode_create(struct hfs_btree *tree, u32 num)
410 {
411         struct hfs_bnode *node;
412         struct page **pagep;
413         int i;
414 
415         spin_lock(&tree->hash_lock);
416         node = hfs_bnode_findhash(tree, num);
417         spin_unlock(&tree->hash_lock);
418         if (node) {
419                 pr_crit("new node %u already hashed?\n", num);
420                 WARN_ON(1);
421                 return node;
422         }
423         node = __hfs_bnode_create(tree, num);
424         if (!node)
425                 return ERR_PTR(-ENOMEM);
426         if (test_bit(HFS_BNODE_ERROR, &node->flags)) {
427                 hfs_bnode_put(node);
428                 return ERR_PTR(-EIO);
429         }
430 
431         pagep = node->page;
432         memset(kmap(*pagep) + node->page_offset, 0,
433                min((int)PAGE_CACHE_SIZE, (int)tree->node_size));
434         set_page_dirty(*pagep);
435         kunmap(*pagep);
436         for (i = 1; i < tree->pages_per_bnode; i++) {
437                 memset(kmap(*++pagep), 0, PAGE_CACHE_SIZE);
438                 set_page_dirty(*pagep);
439                 kunmap(*pagep);
440         }
441         clear_bit(HFS_BNODE_NEW, &node->flags);
442         wake_up(&node->lock_wq);
443 
444         return node;
445 }
446 
447 void hfs_bnode_get(struct hfs_bnode *node)
448 {
449         if (node) {
450                 atomic_inc(&node->refcnt);
451                 hfs_dbg(BNODE_REFS, "get_node(%d:%d): %d\n",
452                         node->tree->cnid, node->this,
453                         atomic_read(&node->refcnt));
454         }
455 }
456 
457 /* Dispose of resources used by a node */
458 void hfs_bnode_put(struct hfs_bnode *node)
459 {
460         if (node) {
461                 struct hfs_btree *tree = node->tree;
462                 int i;
463 
464                 hfs_dbg(BNODE_REFS, "put_node(%d:%d): %d\n",
465                         node->tree->cnid, node->this,
466                         atomic_read(&node->refcnt));
467                 BUG_ON(!atomic_read(&node->refcnt));
468                 if (!atomic_dec_and_lock(&node->refcnt, &tree->hash_lock))
469                         return;
470                 for (i = 0; i < tree->pages_per_bnode; i++) {
471                         if (!node->page[i])
472                                 continue;
473                         mark_page_accessed(node->page[i]);
474                 }
475 
476                 if (test_bit(HFS_BNODE_DELETED, &node->flags)) {
477                         hfs_bnode_unhash(node);
478                         spin_unlock(&tree->hash_lock);
479                         hfs_bmap_free(node);
480                         hfs_bnode_free(node);
481                         return;
482                 }
483                 spin_unlock(&tree->hash_lock);
484         }
485 }
486 

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