GNU Linux-libre 4.19.211-gnu1
[releases.git] / fs / hfs / bnode.c
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, int off, int len)
19 {
20         struct page *page;
21         int pagenum;
22         int bytes_read;
23         int bytes_to_read;
24         void *vaddr;
25
26         off += node->page_offset;
27         pagenum = off >> PAGE_SHIFT;
28         off &= ~PAGE_MASK; /* compute page offset for the first page */
29
30         for (bytes_read = 0; bytes_read < len; bytes_read += bytes_to_read) {
31                 if (pagenum >= node->tree->pages_per_bnode)
32                         break;
33                 page = node->page[pagenum];
34                 bytes_to_read = min_t(int, len - bytes_read, PAGE_SIZE - off);
35
36                 vaddr = kmap_atomic(page);
37                 memcpy(buf + bytes_read, vaddr + off, bytes_to_read);
38                 kunmap_atomic(vaddr);
39
40                 pagenum++;
41                 off = 0; /* page offset only applies to the first page */
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_u8(node, off) + 1;
70         else
71                 key_len = tree->max_key_len + 1;
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 *page;
79
80         off += node->page_offset;
81         page = node->page[0];
82
83         memcpy(kmap(page) + off, buf, len);
84         kunmap(page);
85         set_page_dirty(page);
86 }
87
88 void hfs_bnode_write_u16(struct hfs_bnode *node, int off, u16 data)
89 {
90         __be16 v = cpu_to_be16(data);
91         // optimize later...
92         hfs_bnode_write(node, &v, off, 2);
93 }
94
95 void hfs_bnode_write_u8(struct hfs_bnode *node, int off, u8 data)
96 {
97         // optimize later...
98         hfs_bnode_write(node, &data, off, 1);
99 }
100
101 void hfs_bnode_clear(struct hfs_bnode *node, int off, int len)
102 {
103         struct page *page;
104
105         off += node->page_offset;
106         page = node->page[0];
107
108         memset(kmap(page) + off, 0, len);
109         kunmap(page);
110         set_page_dirty(page);
111 }
112
113 void hfs_bnode_copy(struct hfs_bnode *dst_node, int dst,
114                 struct hfs_bnode *src_node, int src, int len)
115 {
116         struct page *src_page, *dst_page;
117
118         hfs_dbg(BNODE_MOD, "copybytes: %u,%u,%u\n", dst, src, len);
119         if (!len)
120                 return;
121         src += src_node->page_offset;
122         dst += dst_node->page_offset;
123         src_page = src_node->page[0];
124         dst_page = dst_node->page[0];
125
126         memcpy(kmap(dst_page) + dst, kmap(src_page) + src, len);
127         kunmap(src_page);
128         kunmap(dst_page);
129         set_page_dirty(dst_page);
130 }
131
132 void hfs_bnode_move(struct hfs_bnode *node, int dst, int src, int len)
133 {
134         struct page *page;
135         void *ptr;
136
137         hfs_dbg(BNODE_MOD, "movebytes: %u,%u,%u\n", dst, src, len);
138         if (!len)
139                 return;
140         src += node->page_offset;
141         dst += node->page_offset;
142         page = node->page[0];
143         ptr = kmap(page);
144         memmove(ptr + dst, ptr + src, len);
145         kunmap(page);
146         set_page_dirty(page);
147 }
148
149 void hfs_bnode_dump(struct hfs_bnode *node)
150 {
151         struct hfs_bnode_desc desc;
152         __be32 cnid;
153         int i, off, key_off;
154
155         hfs_dbg(BNODE_MOD, "bnode: %d\n", node->this);
156         hfs_bnode_read(node, &desc, 0, sizeof(desc));
157         hfs_dbg(BNODE_MOD, "%d, %d, %d, %d, %d\n",
158                 be32_to_cpu(desc.next), be32_to_cpu(desc.prev),
159                 desc.type, desc.height, be16_to_cpu(desc.num_recs));
160
161         off = node->tree->node_size - 2;
162         for (i = be16_to_cpu(desc.num_recs); i >= 0; off -= 2, i--) {
163                 key_off = hfs_bnode_read_u16(node, off);
164                 hfs_dbg_cont(BNODE_MOD, " %d", key_off);
165                 if (i && node->type == HFS_NODE_INDEX) {
166                         int tmp;
167
168                         if (node->tree->attributes & HFS_TREE_VARIDXKEYS)
169                                 tmp = (hfs_bnode_read_u8(node, key_off) | 1) + 1;
170                         else
171                                 tmp = node->tree->max_key_len + 1;
172                         hfs_dbg_cont(BNODE_MOD, " (%d,%d",
173                                      tmp, hfs_bnode_read_u8(node, key_off));
174                         hfs_bnode_read(node, &cnid, key_off + tmp, 4);
175                         hfs_dbg_cont(BNODE_MOD, ",%d)", be32_to_cpu(cnid));
176                 } else if (i && node->type == HFS_NODE_LEAF) {
177                         int tmp;
178
179                         tmp = hfs_bnode_read_u8(node, key_off);
180                         hfs_dbg_cont(BNODE_MOD, " (%d)", tmp);
181                 }
182         }
183         hfs_dbg_cont(BNODE_MOD, "\n");
184 }
185
186 void hfs_bnode_unlink(struct hfs_bnode *node)
187 {
188         struct hfs_btree *tree;
189         struct hfs_bnode *tmp;
190         __be32 cnid;
191
192         tree = node->tree;
193         if (node->prev) {
194                 tmp = hfs_bnode_find(tree, node->prev);
195                 if (IS_ERR(tmp))
196                         return;
197                 tmp->next = node->next;
198                 cnid = cpu_to_be32(tmp->next);
199                 hfs_bnode_write(tmp, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
200                 hfs_bnode_put(tmp);
201         } else if (node->type == HFS_NODE_LEAF)
202                 tree->leaf_head = node->next;
203
204         if (node->next) {
205                 tmp = hfs_bnode_find(tree, node->next);
206                 if (IS_ERR(tmp))
207                         return;
208                 tmp->prev = node->prev;
209                 cnid = cpu_to_be32(tmp->prev);
210                 hfs_bnode_write(tmp, &cnid, offsetof(struct hfs_bnode_desc, prev), 4);
211                 hfs_bnode_put(tmp);
212         } else if (node->type == HFS_NODE_LEAF)
213                 tree->leaf_tail = node->prev;
214
215         // move down?
216         if (!node->prev && !node->next) {
217                 printk(KERN_DEBUG "hfs_btree_del_level\n");
218         }
219         if (!node->parent) {
220                 tree->root = 0;
221                 tree->depth = 0;
222         }
223         set_bit(HFS_BNODE_DELETED, &node->flags);
224 }
225
226 static inline int hfs_bnode_hash(u32 num)
227 {
228         num = (num >> 16) + num;
229         num += num >> 8;
230         return num & (NODE_HASH_SIZE - 1);
231 }
232
233 struct hfs_bnode *hfs_bnode_findhash(struct hfs_btree *tree, u32 cnid)
234 {
235         struct hfs_bnode *node;
236
237         if (cnid >= tree->node_count) {
238                 pr_err("request for non-existent node %d in B*Tree\n", cnid);
239                 return NULL;
240         }
241
242         for (node = tree->node_hash[hfs_bnode_hash(cnid)];
243              node; node = node->next_hash) {
244                 if (node->this == cnid) {
245                         return node;
246                 }
247         }
248         return NULL;
249 }
250
251 static struct hfs_bnode *__hfs_bnode_create(struct hfs_btree *tree, u32 cnid)
252 {
253         struct hfs_bnode *node, *node2;
254         struct address_space *mapping;
255         struct page *page;
256         int size, block, i, hash;
257         loff_t off;
258
259         if (cnid >= tree->node_count) {
260                 pr_err("request for non-existent node %d in B*Tree\n", cnid);
261                 return NULL;
262         }
263
264         size = sizeof(struct hfs_bnode) + tree->pages_per_bnode *
265                 sizeof(struct page *);
266         node = kzalloc(size, GFP_KERNEL);
267         if (!node)
268                 return NULL;
269         node->tree = tree;
270         node->this = cnid;
271         set_bit(HFS_BNODE_NEW, &node->flags);
272         atomic_set(&node->refcnt, 1);
273         hfs_dbg(BNODE_REFS, "new_node(%d:%d): 1\n",
274                 node->tree->cnid, node->this);
275         init_waitqueue_head(&node->lock_wq);
276         spin_lock(&tree->hash_lock);
277         node2 = hfs_bnode_findhash(tree, cnid);
278         if (!node2) {
279                 hash = hfs_bnode_hash(cnid);
280                 node->next_hash = tree->node_hash[hash];
281                 tree->node_hash[hash] = node;
282                 tree->node_hash_cnt++;
283         } else {
284                 spin_unlock(&tree->hash_lock);
285                 kfree(node);
286                 wait_event(node2->lock_wq, !test_bit(HFS_BNODE_NEW, &node2->flags));
287                 return node2;
288         }
289         spin_unlock(&tree->hash_lock);
290
291         mapping = tree->inode->i_mapping;
292         off = (loff_t)cnid * tree->node_size;
293         block = off >> PAGE_SHIFT;
294         node->page_offset = off & ~PAGE_MASK;
295         for (i = 0; i < tree->pages_per_bnode; i++) {
296                 page = read_mapping_page(mapping, block++, NULL);
297                 if (IS_ERR(page))
298                         goto fail;
299                 if (PageError(page)) {
300                         put_page(page);
301                         goto fail;
302                 }
303                 node->page[i] = page;
304         }
305
306         return node;
307 fail:
308         set_bit(HFS_BNODE_ERROR, &node->flags);
309         return node;
310 }
311
312 void hfs_bnode_unhash(struct hfs_bnode *node)
313 {
314         struct hfs_bnode **p;
315
316         hfs_dbg(BNODE_REFS, "remove_node(%d:%d): %d\n",
317                 node->tree->cnid, node->this, atomic_read(&node->refcnt));
318         for (p = &node->tree->node_hash[hfs_bnode_hash(node->this)];
319              *p && *p != node; p = &(*p)->next_hash)
320                 ;
321         BUG_ON(!*p);
322         *p = node->next_hash;
323         node->tree->node_hash_cnt--;
324 }
325
326 /* Load a particular node out of a tree */
327 struct hfs_bnode *hfs_bnode_find(struct hfs_btree *tree, u32 num)
328 {
329         struct hfs_bnode *node;
330         struct hfs_bnode_desc *desc;
331         int i, rec_off, off, next_off;
332         int entry_size, key_size;
333
334         spin_lock(&tree->hash_lock);
335         node = hfs_bnode_findhash(tree, num);
336         if (node) {
337                 hfs_bnode_get(node);
338                 spin_unlock(&tree->hash_lock);
339                 wait_event(node->lock_wq, !test_bit(HFS_BNODE_NEW, &node->flags));
340                 if (test_bit(HFS_BNODE_ERROR, &node->flags))
341                         goto node_error;
342                 return node;
343         }
344         spin_unlock(&tree->hash_lock);
345         node = __hfs_bnode_create(tree, num);
346         if (!node)
347                 return ERR_PTR(-ENOMEM);
348         if (test_bit(HFS_BNODE_ERROR, &node->flags))
349                 goto node_error;
350         if (!test_bit(HFS_BNODE_NEW, &node->flags))
351                 return node;
352
353         desc = (struct hfs_bnode_desc *)(kmap(node->page[0]) + node->page_offset);
354         node->prev = be32_to_cpu(desc->prev);
355         node->next = be32_to_cpu(desc->next);
356         node->num_recs = be16_to_cpu(desc->num_recs);
357         node->type = desc->type;
358         node->height = desc->height;
359         kunmap(node->page[0]);
360
361         switch (node->type) {
362         case HFS_NODE_HEADER:
363         case HFS_NODE_MAP:
364                 if (node->height != 0)
365                         goto node_error;
366                 break;
367         case HFS_NODE_LEAF:
368                 if (node->height != 1)
369                         goto node_error;
370                 break;
371         case HFS_NODE_INDEX:
372                 if (node->height <= 1 || node->height > tree->depth)
373                         goto node_error;
374                 break;
375         default:
376                 goto node_error;
377         }
378
379         rec_off = tree->node_size - 2;
380         off = hfs_bnode_read_u16(node, rec_off);
381         if (off != sizeof(struct hfs_bnode_desc))
382                 goto node_error;
383         for (i = 1; i <= node->num_recs; off = next_off, i++) {
384                 rec_off -= 2;
385                 next_off = hfs_bnode_read_u16(node, rec_off);
386                 if (next_off <= off ||
387                     next_off > tree->node_size ||
388                     next_off & 1)
389                         goto node_error;
390                 entry_size = next_off - off;
391                 if (node->type != HFS_NODE_INDEX &&
392                     node->type != HFS_NODE_LEAF)
393                         continue;
394                 key_size = hfs_bnode_read_u8(node, off) + 1;
395                 if (key_size >= entry_size /*|| key_size & 1*/)
396                         goto node_error;
397         }
398         clear_bit(HFS_BNODE_NEW, &node->flags);
399         wake_up(&node->lock_wq);
400         return node;
401
402 node_error:
403         set_bit(HFS_BNODE_ERROR, &node->flags);
404         clear_bit(HFS_BNODE_NEW, &node->flags);
405         wake_up(&node->lock_wq);
406         hfs_bnode_put(node);
407         return ERR_PTR(-EIO);
408 }
409
410 void hfs_bnode_free(struct hfs_bnode *node)
411 {
412         int i;
413
414         for (i = 0; i < node->tree->pages_per_bnode; i++)
415                 if (node->page[i])
416                         put_page(node->page[i]);
417         kfree(node);
418 }
419
420 struct hfs_bnode *hfs_bnode_create(struct hfs_btree *tree, u32 num)
421 {
422         struct hfs_bnode *node;
423         struct page **pagep;
424         int i;
425
426         spin_lock(&tree->hash_lock);
427         node = hfs_bnode_findhash(tree, num);
428         spin_unlock(&tree->hash_lock);
429         if (node) {
430                 pr_crit("new node %u already hashed?\n", num);
431                 WARN_ON(1);
432                 return node;
433         }
434         node = __hfs_bnode_create(tree, num);
435         if (!node)
436                 return ERR_PTR(-ENOMEM);
437         if (test_bit(HFS_BNODE_ERROR, &node->flags)) {
438                 hfs_bnode_put(node);
439                 return ERR_PTR(-EIO);
440         }
441
442         pagep = node->page;
443         memset(kmap(*pagep) + node->page_offset, 0,
444                min((int)PAGE_SIZE, (int)tree->node_size));
445         set_page_dirty(*pagep);
446         kunmap(*pagep);
447         for (i = 1; i < tree->pages_per_bnode; i++) {
448                 memset(kmap(*++pagep), 0, PAGE_SIZE);
449                 set_page_dirty(*pagep);
450                 kunmap(*pagep);
451         }
452         clear_bit(HFS_BNODE_NEW, &node->flags);
453         wake_up(&node->lock_wq);
454
455         return node;
456 }
457
458 void hfs_bnode_get(struct hfs_bnode *node)
459 {
460         if (node) {
461                 atomic_inc(&node->refcnt);
462                 hfs_dbg(BNODE_REFS, "get_node(%d:%d): %d\n",
463                         node->tree->cnid, node->this,
464                         atomic_read(&node->refcnt));
465         }
466 }
467
468 /* Dispose of resources used by a node */
469 void hfs_bnode_put(struct hfs_bnode *node)
470 {
471         if (node) {
472                 struct hfs_btree *tree = node->tree;
473                 int i;
474
475                 hfs_dbg(BNODE_REFS, "put_node(%d:%d): %d\n",
476                         node->tree->cnid, node->this,
477                         atomic_read(&node->refcnt));
478                 BUG_ON(!atomic_read(&node->refcnt));
479                 if (!atomic_dec_and_lock(&node->refcnt, &tree->hash_lock))
480                         return;
481                 for (i = 0; i < tree->pages_per_bnode; i++) {
482                         if (!node->page[i])
483                                 continue;
484                         mark_page_accessed(node->page[i]);
485                 }
486
487                 if (test_bit(HFS_BNODE_DELETED, &node->flags)) {
488                         hfs_bnode_unhash(node);
489                         spin_unlock(&tree->hash_lock);
490                         hfs_bmap_free(node);
491                         hfs_bnode_free(node);
492                         return;
493                 }
494                 spin_unlock(&tree->hash_lock);
495         }
496 }