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Linux/fs/hfs/bnode.c

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  1 // SPDX-License-Identifier: GPL-2.0
  2 /*
  3  *  linux/fs/hfs/bnode.c
  4  *
  5  * Copyright (C) 2001
  6  * Brad Boyer (flar@allandria.com)
  7  * (C) 2003 Ardis Technologies <roman@ardistech.com>
  8  *
  9  * Handle basic btree node operations
 10  */
 11 
 12 #include <linux/pagemap.h>
 13 #include <linux/slab.h>
 14 #include <linux/swap.h>
 15 
 16 #include "btree.h"
 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 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         src += src_node->page_offset;
107         dst += dst_node->page_offset;
108         src_page = src_node->page[0];
109         dst_page = dst_node->page[0];
110 
111         memcpy(kmap(dst_page) + dst, kmap(src_page) + src, len);
112         kunmap(src_page);
113         kunmap(dst_page);
114         set_page_dirty(dst_page);
115 }
116 
117 void hfs_bnode_move(struct hfs_bnode *node, int dst, int src, int len)
118 {
119         struct page *page;
120         void *ptr;
121 
122         hfs_dbg(BNODE_MOD, "movebytes: %u,%u,%u\n", dst, src, len);
123         if (!len)
124                 return;
125         src += node->page_offset;
126         dst += node->page_offset;
127         page = node->page[0];
128         ptr = kmap(page);
129         memmove(ptr + dst, ptr + src, len);
130         kunmap(page);
131         set_page_dirty(page);
132 }
133 
134 void hfs_bnode_dump(struct hfs_bnode *node)
135 {
136         struct hfs_bnode_desc desc;
137         __be32 cnid;
138         int i, off, key_off;
139 
140         hfs_dbg(BNODE_MOD, "bnode: %d\n", node->this);
141         hfs_bnode_read(node, &desc, 0, sizeof(desc));
142         hfs_dbg(BNODE_MOD, "%d, %d, %d, %d, %d\n",
143                 be32_to_cpu(desc.next), be32_to_cpu(desc.prev),
144                 desc.type, desc.height, be16_to_cpu(desc.num_recs));
145 
146         off = node->tree->node_size - 2;
147         for (i = be16_to_cpu(desc.num_recs); i >= 0; off -= 2, i--) {
148                 key_off = hfs_bnode_read_u16(node, off);
149                 hfs_dbg_cont(BNODE_MOD, " %d", key_off);
150                 if (i && node->type == HFS_NODE_INDEX) {
151                         int tmp;
152 
153                         if (node->tree->attributes & HFS_TREE_VARIDXKEYS)
154                                 tmp = (hfs_bnode_read_u8(node, key_off) | 1) + 1;
155                         else
156                                 tmp = node->tree->max_key_len + 1;
157                         hfs_dbg_cont(BNODE_MOD, " (%d,%d",
158                                      tmp, hfs_bnode_read_u8(node, key_off));
159                         hfs_bnode_read(node, &cnid, key_off + tmp, 4);
160                         hfs_dbg_cont(BNODE_MOD, ",%d)", be32_to_cpu(cnid));
161                 } else if (i && node->type == HFS_NODE_LEAF) {
162                         int tmp;
163 
164                         tmp = hfs_bnode_read_u8(node, key_off);
165                         hfs_dbg_cont(BNODE_MOD, " (%d)", tmp);
166                 }
167         }
168         hfs_dbg_cont(BNODE_MOD, "\n");
169 }
170 
171 void hfs_bnode_unlink(struct hfs_bnode *node)
172 {
173         struct hfs_btree *tree;
174         struct hfs_bnode *tmp;
175         __be32 cnid;
176 
177         tree = node->tree;
178         if (node->prev) {
179                 tmp = hfs_bnode_find(tree, node->prev);
180                 if (IS_ERR(tmp))
181                         return;
182                 tmp->next = node->next;
183                 cnid = cpu_to_be32(tmp->next);
184                 hfs_bnode_write(tmp, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
185                 hfs_bnode_put(tmp);
186         } else if (node->type == HFS_NODE_LEAF)
187                 tree->leaf_head = node->next;
188 
189         if (node->next) {
190                 tmp = hfs_bnode_find(tree, node->next);
191                 if (IS_ERR(tmp))
192                         return;
193                 tmp->prev = node->prev;
194                 cnid = cpu_to_be32(tmp->prev);
195                 hfs_bnode_write(tmp, &cnid, offsetof(struct hfs_bnode_desc, prev), 4);
196                 hfs_bnode_put(tmp);
197         } else if (node->type == HFS_NODE_LEAF)
198                 tree->leaf_tail = node->prev;
199 
200         // move down?
201         if (!node->prev && !node->next) {
202                 printk(KERN_DEBUG "hfs_btree_del_level\n");
203         }
204         if (!node->parent) {
205                 tree->root = 0;
206                 tree->depth = 0;
207         }
208         set_bit(HFS_BNODE_DELETED, &node->flags);
209 }
210 
211 static inline int hfs_bnode_hash(u32 num)
212 {
213         num = (num >> 16) + num;
214         num += num >> 8;
215         return num & (NODE_HASH_SIZE - 1);
216 }
217 
218 struct hfs_bnode *hfs_bnode_findhash(struct hfs_btree *tree, u32 cnid)
219 {
220         struct hfs_bnode *node;
221 
222         if (cnid >= tree->node_count) {
223                 pr_err("request for non-existent node %d in B*Tree\n", cnid);
224                 return NULL;
225         }
226 
227         for (node = tree->node_hash[hfs_bnode_hash(cnid)];
228              node; node = node->next_hash) {
229                 if (node->this == cnid) {
230                         return node;
231                 }
232         }
233         return NULL;
234 }
235 
236 static struct hfs_bnode *__hfs_bnode_create(struct hfs_btree *tree, u32 cnid)
237 {
238         struct hfs_bnode *node, *node2;
239         struct address_space *mapping;
240         struct page *page;
241         int size, block, i, hash;
242         loff_t off;
243 
244         if (cnid >= tree->node_count) {
245                 pr_err("request for non-existent node %d in B*Tree\n", cnid);
246                 return NULL;
247         }
248 
249         size = sizeof(struct hfs_bnode) + tree->pages_per_bnode *
250                 sizeof(struct page *);
251         node = kzalloc(size, GFP_KERNEL);
252         if (!node)
253                 return NULL;
254         node->tree = tree;
255         node->this = cnid;
256         set_bit(HFS_BNODE_NEW, &node->flags);
257         atomic_set(&node->refcnt, 1);
258         hfs_dbg(BNODE_REFS, "new_node(%d:%d): 1\n",
259                 node->tree->cnid, node->this);
260         init_waitqueue_head(&node->lock_wq);
261         spin_lock(&tree->hash_lock);
262         node2 = hfs_bnode_findhash(tree, cnid);
263         if (!node2) {
264                 hash = hfs_bnode_hash(cnid);
265                 node->next_hash = tree->node_hash[hash];
266                 tree->node_hash[hash] = node;
267                 tree->node_hash_cnt++;
268         } else {
269                 spin_unlock(&tree->hash_lock);
270                 kfree(node);
271                 wait_event(node2->lock_wq, !test_bit(HFS_BNODE_NEW, &node2->flags));
272                 return node2;
273         }
274         spin_unlock(&tree->hash_lock);
275 
276         mapping = tree->inode->i_mapping;
277         off = (loff_t)cnid * tree->node_size;
278         block = off >> PAGE_SHIFT;
279         node->page_offset = off & ~PAGE_MASK;
280         for (i = 0; i < tree->pages_per_bnode; i++) {
281                 page = read_mapping_page(mapping, block++, NULL);
282                 if (IS_ERR(page))
283                         goto fail;
284                 if (PageError(page)) {
285                         put_page(page);
286                         goto fail;
287                 }
288                 node->page[i] = page;
289         }
290 
291         return node;
292 fail:
293         set_bit(HFS_BNODE_ERROR, &node->flags);
294         return node;
295 }
296 
297 void hfs_bnode_unhash(struct hfs_bnode *node)
298 {
299         struct hfs_bnode **p;
300 
301         hfs_dbg(BNODE_REFS, "remove_node(%d:%d): %d\n",
302                 node->tree->cnid, node->this, atomic_read(&node->refcnt));
303         for (p = &node->tree->node_hash[hfs_bnode_hash(node->this)];
304              *p && *p != node; p = &(*p)->next_hash)
305                 ;
306         BUG_ON(!*p);
307         *p = node->next_hash;
308         node->tree->node_hash_cnt--;
309 }
310 
311 /* Load a particular node out of a tree */
312 struct hfs_bnode *hfs_bnode_find(struct hfs_btree *tree, u32 num)
313 {
314         struct hfs_bnode *node;
315         struct hfs_bnode_desc *desc;
316         int i, rec_off, off, next_off;
317         int entry_size, key_size;
318 
319         spin_lock(&tree->hash_lock);
320         node = hfs_bnode_findhash(tree, num);
321         if (node) {
322                 hfs_bnode_get(node);
323                 spin_unlock(&tree->hash_lock);
324                 wait_event(node->lock_wq, !test_bit(HFS_BNODE_NEW, &node->flags));
325                 if (test_bit(HFS_BNODE_ERROR, &node->flags))
326                         goto node_error;
327                 return node;
328         }
329         spin_unlock(&tree->hash_lock);
330         node = __hfs_bnode_create(tree, num);
331         if (!node)
332                 return ERR_PTR(-ENOMEM);
333         if (test_bit(HFS_BNODE_ERROR, &node->flags))
334                 goto node_error;
335         if (!test_bit(HFS_BNODE_NEW, &node->flags))
336                 return node;
337 
338         desc = (struct hfs_bnode_desc *)(kmap(node->page[0]) + node->page_offset);
339         node->prev = be32_to_cpu(desc->prev);
340         node->next = be32_to_cpu(desc->next);
341         node->num_recs = be16_to_cpu(desc->num_recs);
342         node->type = desc->type;
343         node->height = desc->height;
344         kunmap(node->page[0]);
345 
346         switch (node->type) {
347         case HFS_NODE_HEADER:
348         case HFS_NODE_MAP:
349                 if (node->height != 0)
350                         goto node_error;
351                 break;
352         case HFS_NODE_LEAF:
353                 if (node->height != 1)
354                         goto node_error;
355                 break;
356         case HFS_NODE_INDEX:
357                 if (node->height <= 1 || node->height > tree->depth)
358                         goto node_error;
359                 break;
360         default:
361                 goto node_error;
362         }
363 
364         rec_off = tree->node_size - 2;
365         off = hfs_bnode_read_u16(node, rec_off);
366         if (off != sizeof(struct hfs_bnode_desc))
367                 goto node_error;
368         for (i = 1; i <= node->num_recs; off = next_off, i++) {
369                 rec_off -= 2;
370                 next_off = hfs_bnode_read_u16(node, rec_off);
371                 if (next_off <= off ||
372                     next_off > tree->node_size ||
373                     next_off & 1)
374                         goto node_error;
375                 entry_size = next_off - off;
376                 if (node->type != HFS_NODE_INDEX &&
377                     node->type != HFS_NODE_LEAF)
378                         continue;
379                 key_size = hfs_bnode_read_u8(node, off) + 1;
380                 if (key_size >= entry_size /*|| key_size & 1*/)
381                         goto node_error;
382         }
383         clear_bit(HFS_BNODE_NEW, &node->flags);
384         wake_up(&node->lock_wq);
385         return node;
386 
387 node_error:
388         set_bit(HFS_BNODE_ERROR, &node->flags);
389         clear_bit(HFS_BNODE_NEW, &node->flags);
390         wake_up(&node->lock_wq);
391         hfs_bnode_put(node);
392         return ERR_PTR(-EIO);
393 }
394 
395 void hfs_bnode_free(struct hfs_bnode *node)
396 {
397         int i;
398 
399         for (i = 0; i < node->tree->pages_per_bnode; i++)
400                 if (node->page[i])
401                         put_page(node->page[i]);
402         kfree(node);
403 }
404 
405 struct hfs_bnode *hfs_bnode_create(struct hfs_btree *tree, u32 num)
406 {
407         struct hfs_bnode *node;
408         struct page **pagep;
409         int i;
410 
411         spin_lock(&tree->hash_lock);
412         node = hfs_bnode_findhash(tree, num);
413         spin_unlock(&tree->hash_lock);
414         if (node) {
415                 pr_crit("new node %u already hashed?\n", num);
416                 WARN_ON(1);
417                 return node;
418         }
419         node = __hfs_bnode_create(tree, num);
420         if (!node)
421                 return ERR_PTR(-ENOMEM);
422         if (test_bit(HFS_BNODE_ERROR, &node->flags)) {
423                 hfs_bnode_put(node);
424                 return ERR_PTR(-EIO);
425         }
426 
427         pagep = node->page;
428         memset(kmap(*pagep) + node->page_offset, 0,
429                min((int)PAGE_SIZE, (int)tree->node_size));
430         set_page_dirty(*pagep);
431         kunmap(*pagep);
432         for (i = 1; i < tree->pages_per_bnode; i++) {
433                 memset(kmap(*++pagep), 0, PAGE_SIZE);
434                 set_page_dirty(*pagep);
435                 kunmap(*pagep);
436         }
437         clear_bit(HFS_BNODE_NEW, &node->flags);
438         wake_up(&node->lock_wq);
439 
440         return node;
441 }
442 
443 void hfs_bnode_get(struct hfs_bnode *node)
444 {
445         if (node) {
446                 atomic_inc(&node->refcnt);
447                 hfs_dbg(BNODE_REFS, "get_node(%d:%d): %d\n",
448                         node->tree->cnid, node->this,
449                         atomic_read(&node->refcnt));
450         }
451 }
452 
453 /* Dispose of resources used by a node */
454 void hfs_bnode_put(struct hfs_bnode *node)
455 {
456         if (node) {
457                 struct hfs_btree *tree = node->tree;
458                 int i;
459 
460                 hfs_dbg(BNODE_REFS, "put_node(%d:%d): %d\n",
461                         node->tree->cnid, node->this,
462                         atomic_read(&node->refcnt));
463                 BUG_ON(!atomic_read(&node->refcnt));
464                 if (!atomic_dec_and_lock(&node->refcnt, &tree->hash_lock))
465                         return;
466                 for (i = 0; i < tree->pages_per_bnode; i++) {
467                         if (!node->page[i])
468                                 continue;
469                         mark_page_accessed(node->page[i]);
470                 }
471 
472                 if (test_bit(HFS_BNODE_DELETED, &node->flags)) {
473                         hfs_bnode_unhash(node);
474                         spin_unlock(&tree->hash_lock);
475                         hfs_bmap_free(node);
476                         hfs_bnode_free(node);
477                         return;
478                 }
479                 spin_unlock(&tree->hash_lock);
480         }
481 }
482 

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