1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * linux/fs/hfs/btree.c
4 *
5 * Copyright (C) 2001
6 * Brad Boyer (flar@allandria.com)
7 * (C) 2003 Ardis Technologies <roman@ardistech.com>
8 *
9 * Handle opening/closing btree
10 */
11
12 #include <linux/pagemap.h>
13 #include <linux/slab.h>
14 #include <linux/log2.h>
15
16 #include "btree.h"
17
18 /* Get a reference to a B*Tree and do some initial checks */
19 struct hfs_btree *hfs_btree_open(struct super_block *sb, u32 id, btree_keycmp keycmp)
20 {
21 struct hfs_btree *tree;
22 struct hfs_btree_header_rec *head;
23 struct address_space *mapping;
24 struct page *page;
25 unsigned int size;
26
27 tree = kzalloc(sizeof(*tree), GFP_KERNEL);
28 if (!tree)
29 return NULL;
30
31 mutex_init(&tree->tree_lock);
32 spin_lock_init(&tree->hash_lock);
33 /* Set the correct compare function */
34 tree->sb = sb;
35 tree->cnid = id;
36 tree->keycmp = keycmp;
37
38 tree->inode = iget_locked(sb, id);
39 if (!tree->inode)
40 goto free_tree;
41 BUG_ON(!(tree->inode->i_state & I_NEW));
42 {
43 struct hfs_mdb *mdb = HFS_SB(sb)->mdb;
44 HFS_I(tree->inode)->flags = 0;
45 mutex_init(&HFS_I(tree->inode)->extents_lock);
46 switch (id) {
47 case HFS_EXT_CNID:
48 hfs_inode_read_fork(tree->inode, mdb->drXTExtRec, mdb->drXTFlSize,
49 mdb->drXTFlSize, be32_to_cpu(mdb->drXTClpSiz));
50 if (HFS_I(tree->inode)->alloc_blocks >
51 HFS_I(tree->inode)->first_blocks) {
52 pr_err("invalid btree extent records\n");
53 unlock_new_inode(tree->inode);
54 goto free_inode;
55 }
56
57 tree->inode->i_mapping->a_ops = &hfs_btree_aops;
58 break;
59 case HFS_CAT_CNID:
60 hfs_inode_read_fork(tree->inode, mdb->drCTExtRec, mdb->drCTFlSize,
61 mdb->drCTFlSize, be32_to_cpu(mdb->drCTClpSiz));
62
63 if (!HFS_I(tree->inode)->first_blocks) {
64 pr_err("invalid btree extent records (0 size)\n");
65 unlock_new_inode(tree->inode);
66 goto free_inode;
67 }
68
69 tree->inode->i_mapping->a_ops = &hfs_btree_aops;
70 break;
71 default:
72 BUG();
73 }
74 }
75 unlock_new_inode(tree->inode);
76
77 mapping = tree->inode->i_mapping;
78 page = read_mapping_page(mapping, 0, NULL);
79 if (IS_ERR(page))
80 goto free_inode;
81
82 /* Load the header */
83 head = (struct hfs_btree_header_rec *)(kmap_local_page(page) +
84 sizeof(struct hfs_bnode_desc));
85 tree->root = be32_to_cpu(head->root);
86 tree->leaf_count = be32_to_cpu(head->leaf_count);
87 tree->leaf_head = be32_to_cpu(head->leaf_head);
88 tree->leaf_tail = be32_to_cpu(head->leaf_tail);
89 tree->node_count = be32_to_cpu(head->node_count);
90 tree->free_nodes = be32_to_cpu(head->free_nodes);
91 tree->attributes = be32_to_cpu(head->attributes);
92 tree->node_size = be16_to_cpu(head->node_size);
93 tree->max_key_len = be16_to_cpu(head->max_key_len);
94 tree->depth = be16_to_cpu(head->depth);
95
96 size = tree->node_size;
97 if (!is_power_of_2(size))
98 goto fail_page;
99 if (!tree->node_count)
100 goto fail_page;
101 switch (id) {
102 case HFS_EXT_CNID:
103 if (tree->max_key_len != HFS_MAX_EXT_KEYLEN) {
104 pr_err("invalid extent max_key_len %d\n",
105 tree->max_key_len);
106 goto fail_page;
107 }
108 break;
109 case HFS_CAT_CNID:
110 if (tree->max_key_len != HFS_MAX_CAT_KEYLEN) {
111 pr_err("invalid catalog max_key_len %d\n",
112 tree->max_key_len);
113 goto fail_page;
114 }
115 break;
116 default:
117 BUG();
118 }
119
120 tree->node_size_shift = ffs(size) - 1;
121 tree->pages_per_bnode = (tree->node_size + PAGE_SIZE - 1) >> PAGE_SHIFT;
122
123 kunmap_local(head);
124 put_page(page);
125 return tree;
126
127 fail_page:
128 kunmap_local(head);
129 put_page(page);
130 free_inode:
131 tree->inode->i_mapping->a_ops = &hfs_aops;
132 iput(tree->inode);
133 free_tree:
134 kfree(tree);
135 return NULL;
136 }
137
138 /* Release resources used by a btree */
139 void hfs_btree_close(struct hfs_btree *tree)
140 {
141 struct hfs_bnode *node;
142 int i;
143
144 if (!tree)
145 return;
146
147 for (i = 0; i < NODE_HASH_SIZE; i++) {
148 while ((node = tree->node_hash[i])) {
149 tree->node_hash[i] = node->next_hash;
150 if (atomic_read(&node->refcnt))
151 pr_err("node %d:%d still has %d user(s)!\n",
152 node->tree->cnid, node->this,
153 atomic_read(&node->refcnt));
154 hfs_bnode_free(node);
155 tree->node_hash_cnt--;
156 }
157 }
158 iput(tree->inode);
159 kfree(tree);
160 }
161
162 void hfs_btree_write(struct hfs_btree *tree)
163 {
164 struct hfs_btree_header_rec *head;
165 struct hfs_bnode *node;
166 struct page *page;
167
168 node = hfs_bnode_find(tree, 0);
169 if (IS_ERR(node))
170 /* panic? */
171 return;
172 /* Load the header */
173 page = node->page[0];
174 head = (struct hfs_btree_header_rec *)(kmap_local_page(page) +
175 sizeof(struct hfs_bnode_desc));
176
177 head->root = cpu_to_be32(tree->root);
178 head->leaf_count = cpu_to_be32(tree->leaf_count);
179 head->leaf_head = cpu_to_be32(tree->leaf_head);
180 head->leaf_tail = cpu_to_be32(tree->leaf_tail);
181 head->node_count = cpu_to_be32(tree->node_count);
182 head->free_nodes = cpu_to_be32(tree->free_nodes);
183 head->attributes = cpu_to_be32(tree->attributes);
184 head->depth = cpu_to_be16(tree->depth);
185
186 kunmap_local(head);
187 set_page_dirty(page);
188 hfs_bnode_put(node);
189 }
190
191 static struct hfs_bnode *hfs_bmap_new_bmap(struct hfs_bnode *prev, u32 idx)
192 {
193 struct hfs_btree *tree = prev->tree;
194 struct hfs_bnode *node;
195 struct hfs_bnode_desc desc;
196 __be32 cnid;
197
198 node = hfs_bnode_create(tree, idx);
199 if (IS_ERR(node))
200 return node;
201
202 if (!tree->free_nodes)
203 panic("FIXME!!!");
204 tree->free_nodes--;
205 prev->next = idx;
206 cnid = cpu_to_be32(idx);
207 hfs_bnode_write(prev, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
208
209 node->type = HFS_NODE_MAP;
210 node->num_recs = 1;
211 hfs_bnode_clear(node, 0, tree->node_size);
212 desc.next = 0;
213 desc.prev = 0;
214 desc.type = HFS_NODE_MAP;
215 desc.height = 0;
216 desc.num_recs = cpu_to_be16(1);
217 desc.reserved = 0;
218 hfs_bnode_write(node, &desc, 0, sizeof(desc));
219 hfs_bnode_write_u16(node, 14, 0x8000);
220 hfs_bnode_write_u16(node, tree->node_size - 2, 14);
221 hfs_bnode_write_u16(node, tree->node_size - 4, tree->node_size - 6);
222
223 return node;
224 }
225
226 /* Make sure @tree has enough space for the @rsvd_nodes */
227 int hfs_bmap_reserve(struct hfs_btree *tree, int rsvd_nodes)
228 {
229 struct inode *inode = tree->inode;
230 u32 count;
231 int res;
232
233 while (tree->free_nodes < rsvd_nodes) {
234 res = hfs_extend_file(inode);
235 if (res)
236 return res;
237 HFS_I(inode)->phys_size = inode->i_size =
238 (loff_t)HFS_I(inode)->alloc_blocks *
239 HFS_SB(tree->sb)->alloc_blksz;
240 HFS_I(inode)->fs_blocks = inode->i_size >>
241 tree->sb->s_blocksize_bits;
242 inode_set_bytes(inode, inode->i_size);
243 count = inode->i_size >> tree->node_size_shift;
244 tree->free_nodes += count - tree->node_count;
245 tree->node_count = count;
246 }
247 return 0;
248 }
249
250 struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree)
251 {
252 struct hfs_bnode *node, *next_node;
253 struct page **pagep;
254 u32 nidx, idx;
255 unsigned off;
256 u16 off16;
257 u16 len;
258 u8 *data, byte, m;
259 int i, res;
260
261 res = hfs_bmap_reserve(tree, 1);
262 if (res)
263 return ERR_PTR(res);
264
265 nidx = 0;
266 node = hfs_bnode_find(tree, nidx);
267 if (IS_ERR(node))
268 return node;
269 len = hfs_brec_lenoff(node, 2, &off16);
270 off = off16;
271
272 off += node->page_offset;
273 pagep = node->page + (off >> PAGE_SHIFT);
274 data = kmap_local_page(*pagep);
275 off &= ~PAGE_MASK;
276 idx = 0;
277
278 for (;;) {
279 while (len) {
280 byte = data[off];
281 if (byte != 0xff) {
282 for (m = 0x80, i = 0; i < 8; m >>= 1, i++) {
283 if (!(byte & m)) {
284 idx += i;
285 data[off] |= m;
286 set_page_dirty(*pagep);
287 kunmap_local(data);
288 tree->free_nodes--;
289 mark_inode_dirty(tree->inode);
290 hfs_bnode_put(node);
291 return hfs_bnode_create(tree, idx);
292 }
293 }
294 }
295 if (++off >= PAGE_SIZE) {
296 kunmap_local(data);
297 data = kmap_local_page(*++pagep);
298 off = 0;
299 }
300 idx += 8;
301 len--;
302 }
303 kunmap_local(data);
304 nidx = node->next;
305 if (!nidx) {
306 printk(KERN_DEBUG "create new bmap node...\n");
307 next_node = hfs_bmap_new_bmap(node, idx);
308 } else
309 next_node = hfs_bnode_find(tree, nidx);
310 hfs_bnode_put(node);
311 if (IS_ERR(next_node))
312 return next_node;
313 node = next_node;
314
315 len = hfs_brec_lenoff(node, 0, &off16);
316 off = off16;
317 off += node->page_offset;
318 pagep = node->page + (off >> PAGE_SHIFT);
319 data = kmap_local_page(*pagep);
320 off &= ~PAGE_MASK;
321 }
322 }
323
324 void hfs_bmap_free(struct hfs_bnode *node)
325 {
326 struct hfs_btree *tree;
327 struct page *page;
328 u16 off, len;
329 u32 nidx;
330 u8 *data, byte, m;
331
332 hfs_dbg(BNODE_MOD, "btree_free_node: %u\n", node->this);
333 tree = node->tree;
334 nidx = node->this;
335 node = hfs_bnode_find(tree, 0);
336 if (IS_ERR(node))
337 return;
338 len = hfs_brec_lenoff(node, 2, &off);
339 while (nidx >= len * 8) {
340 u32 i;
341
342 nidx -= len * 8;
343 i = node->next;
344 if (!i) {
345 /* panic */;
346 pr_crit("unable to free bnode %u. bmap not found!\n",
347 node->this);
348 hfs_bnode_put(node);
349 return;
350 }
351 hfs_bnode_put(node);
352 node = hfs_bnode_find(tree, i);
353 if (IS_ERR(node))
354 return;
355 if (node->type != HFS_NODE_MAP) {
356 /* panic */;
357 pr_crit("invalid bmap found! (%u,%d)\n",
358 node->this, node->type);
359 hfs_bnode_put(node);
360 return;
361 }
362 len = hfs_brec_lenoff(node, 0, &off);
363 }
364 off += node->page_offset + nidx / 8;
365 page = node->page[off >> PAGE_SHIFT];
366 data = kmap_local_page(page);
367 off &= ~PAGE_MASK;
368 m = 1 << (~nidx & 7);
369 byte = data[off];
370 if (!(byte & m)) {
371 pr_crit("trying to free free bnode %u(%d)\n",
372 node->this, node->type);
373 kunmap_local(data);
374 hfs_bnode_put(node);
375 return;
376 }
377 data[off] = byte & ~m;
378 set_page_dirty(page);
379 kunmap_local(data);
380 hfs_bnode_put(node);
381 tree->free_nodes++;
382 mark_inode_dirty(tree->inode);
383 }
384
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