GNU Linux-libre 4.9.308-gnu1
[releases.git] / fs / hfsplus / btree.c
1 /*
2  *  linux/fs/hfsplus/btree.c
3  *
4  * Copyright (C) 2001
5  * Brad Boyer (flar@allandria.com)
6  * (C) 2003 Ardis Technologies <roman@ardistech.com>
7  *
8  * Handle opening/closing btree
9  */
10
11 #include <linux/slab.h>
12 #include <linux/pagemap.h>
13 #include <linux/log2.h>
14
15 #include "hfsplus_fs.h"
16 #include "hfsplus_raw.h"
17
18 /*
19  * Initial source code of clump size calculation is gotten
20  * from http://opensource.apple.com/tarballs/diskdev_cmds/
21  */
22 #define CLUMP_ENTRIES   15
23
24 static short clumptbl[CLUMP_ENTRIES * 3] = {
25 /*
26  *          Volume      Attributes       Catalog         Extents
27  *           Size       Clump (MB)      Clump (MB)      Clump (MB)
28  */
29         /*   1GB */       4,              4,             4,
30         /*   2GB */       6,              6,             4,
31         /*   4GB */       8,              8,             4,
32         /*   8GB */      11,             11,             5,
33         /*
34          * For volumes 16GB and larger, we want to make sure that a full OS
35          * install won't require fragmentation of the Catalog or Attributes
36          * B-trees.  We do this by making the clump sizes sufficiently large,
37          * and by leaving a gap after the B-trees for them to grow into.
38          *
39          * For SnowLeopard 10A298, a FullNetInstall with all packages selected
40          * results in:
41          * Catalog B-tree Header
42          *      nodeSize:          8192
43          *      totalNodes:       31616
44          *      freeNodes:         1978
45          * (used = 231.55 MB)
46          * Attributes B-tree Header
47          *      nodeSize:          8192
48          *      totalNodes:       63232
49          *      freeNodes:          958
50          * (used = 486.52 MB)
51          *
52          * We also want Time Machine backup volumes to have a sufficiently
53          * large clump size to reduce fragmentation.
54          *
55          * The series of numbers for Catalog and Attribute form a geometric
56          * series. For Catalog (16GB to 512GB), each term is 8**(1/5) times
57          * the previous term.  For Attributes (16GB to 512GB), each term is
58          * 4**(1/5) times the previous term.  For 1TB to 16TB, each term is
59          * 2**(1/5) times the previous term.
60          */
61         /*  16GB */      64,             32,             5,
62         /*  32GB */      84,             49,             6,
63         /*  64GB */     111,             74,             7,
64         /* 128GB */     147,            111,             8,
65         /* 256GB */     194,            169,             9,
66         /* 512GB */     256,            256,            11,
67         /*   1TB */     294,            294,            14,
68         /*   2TB */     338,            338,            16,
69         /*   4TB */     388,            388,            20,
70         /*   8TB */     446,            446,            25,
71         /*  16TB */     512,            512,            32
72 };
73
74 u32 hfsplus_calc_btree_clump_size(u32 block_size, u32 node_size,
75                                         u64 sectors, int file_id)
76 {
77         u32 mod = max(node_size, block_size);
78         u32 clump_size;
79         int column;
80         int i;
81
82         /* Figure out which column of the above table to use for this file. */
83         switch (file_id) {
84         case HFSPLUS_ATTR_CNID:
85                 column = 0;
86                 break;
87         case HFSPLUS_CAT_CNID:
88                 column = 1;
89                 break;
90         default:
91                 column = 2;
92                 break;
93         }
94
95         /*
96          * The default clump size is 0.8% of the volume size. And
97          * it must also be a multiple of the node and block size.
98          */
99         if (sectors < 0x200000) {
100                 clump_size = sectors << 2;      /*  0.8 %  */
101                 if (clump_size < (8 * node_size))
102                         clump_size = 8 * node_size;
103         } else {
104                 /* turn exponent into table index... */
105                 for (i = 0, sectors = sectors >> 22;
106                      sectors && (i < CLUMP_ENTRIES - 1);
107                      ++i, sectors = sectors >> 1) {
108                         /* empty body */
109                 }
110
111                 clump_size = clumptbl[column + (i) * 3] * 1024 * 1024;
112         }
113
114         /*
115          * Round the clump size to a multiple of node and block size.
116          * NOTE: This rounds down.
117          */
118         clump_size /= mod;
119         clump_size *= mod;
120
121         /*
122          * Rounding down could have rounded down to 0 if the block size was
123          * greater than the clump size.  If so, just use one block or node.
124          */
125         if (clump_size == 0)
126                 clump_size = mod;
127
128         return clump_size;
129 }
130
131 /* Get a reference to a B*Tree and do some initial checks */
132 struct hfs_btree *hfs_btree_open(struct super_block *sb, u32 id)
133 {
134         struct hfs_btree *tree;
135         struct hfs_btree_header_rec *head;
136         struct address_space *mapping;
137         struct inode *inode;
138         struct page *page;
139         unsigned int size;
140
141         tree = kzalloc(sizeof(*tree), GFP_KERNEL);
142         if (!tree)
143                 return NULL;
144
145         mutex_init(&tree->tree_lock);
146         spin_lock_init(&tree->hash_lock);
147         tree->sb = sb;
148         tree->cnid = id;
149         inode = hfsplus_iget(sb, id);
150         if (IS_ERR(inode))
151                 goto free_tree;
152         tree->inode = inode;
153
154         if (!HFSPLUS_I(tree->inode)->first_blocks) {
155                 pr_err("invalid btree extent records (0 size)\n");
156                 goto free_inode;
157         }
158
159         mapping = tree->inode->i_mapping;
160         page = read_mapping_page(mapping, 0, NULL);
161         if (IS_ERR(page))
162                 goto free_inode;
163
164         /* Load the header */
165         head = (struct hfs_btree_header_rec *)(kmap(page) +
166                 sizeof(struct hfs_bnode_desc));
167         tree->root = be32_to_cpu(head->root);
168         tree->leaf_count = be32_to_cpu(head->leaf_count);
169         tree->leaf_head = be32_to_cpu(head->leaf_head);
170         tree->leaf_tail = be32_to_cpu(head->leaf_tail);
171         tree->node_count = be32_to_cpu(head->node_count);
172         tree->free_nodes = be32_to_cpu(head->free_nodes);
173         tree->attributes = be32_to_cpu(head->attributes);
174         tree->node_size = be16_to_cpu(head->node_size);
175         tree->max_key_len = be16_to_cpu(head->max_key_len);
176         tree->depth = be16_to_cpu(head->depth);
177
178         /* Verify the tree and set the correct compare function */
179         switch (id) {
180         case HFSPLUS_EXT_CNID:
181                 if (tree->max_key_len != HFSPLUS_EXT_KEYLEN - sizeof(u16)) {
182                         pr_err("invalid extent max_key_len %d\n",
183                                 tree->max_key_len);
184                         goto fail_page;
185                 }
186                 if (tree->attributes & HFS_TREE_VARIDXKEYS) {
187                         pr_err("invalid extent btree flag\n");
188                         goto fail_page;
189                 }
190
191                 tree->keycmp = hfsplus_ext_cmp_key;
192                 break;
193         case HFSPLUS_CAT_CNID:
194                 if (tree->max_key_len != HFSPLUS_CAT_KEYLEN - sizeof(u16)) {
195                         pr_err("invalid catalog max_key_len %d\n",
196                                 tree->max_key_len);
197                         goto fail_page;
198                 }
199                 if (!(tree->attributes & HFS_TREE_VARIDXKEYS)) {
200                         pr_err("invalid catalog btree flag\n");
201                         goto fail_page;
202                 }
203
204                 if (test_bit(HFSPLUS_SB_HFSX, &HFSPLUS_SB(sb)->flags) &&
205                     (head->key_type == HFSPLUS_KEY_BINARY))
206                         tree->keycmp = hfsplus_cat_bin_cmp_key;
207                 else {
208                         tree->keycmp = hfsplus_cat_case_cmp_key;
209                         set_bit(HFSPLUS_SB_CASEFOLD, &HFSPLUS_SB(sb)->flags);
210                 }
211                 break;
212         case HFSPLUS_ATTR_CNID:
213                 if (tree->max_key_len != HFSPLUS_ATTR_KEYLEN - sizeof(u16)) {
214                         pr_err("invalid attributes max_key_len %d\n",
215                                 tree->max_key_len);
216                         goto fail_page;
217                 }
218                 tree->keycmp = hfsplus_attr_bin_cmp_key;
219                 break;
220         default:
221                 pr_err("unknown B*Tree requested\n");
222                 goto fail_page;
223         }
224
225         if (!(tree->attributes & HFS_TREE_BIGKEYS)) {
226                 pr_err("invalid btree flag\n");
227                 goto fail_page;
228         }
229
230         size = tree->node_size;
231         if (!is_power_of_2(size))
232                 goto fail_page;
233         if (!tree->node_count)
234                 goto fail_page;
235
236         tree->node_size_shift = ffs(size) - 1;
237
238         tree->pages_per_bnode =
239                 (tree->node_size + PAGE_SIZE - 1) >>
240                 PAGE_SHIFT;
241
242         kunmap(page);
243         put_page(page);
244         return tree;
245
246  fail_page:
247         put_page(page);
248  free_inode:
249         tree->inode->i_mapping->a_ops = &hfsplus_aops;
250         iput(tree->inode);
251  free_tree:
252         kfree(tree);
253         return NULL;
254 }
255
256 /* Release resources used by a btree */
257 void hfs_btree_close(struct hfs_btree *tree)
258 {
259         struct hfs_bnode *node;
260         int i;
261
262         if (!tree)
263                 return;
264
265         for (i = 0; i < NODE_HASH_SIZE; i++) {
266                 while ((node = tree->node_hash[i])) {
267                         tree->node_hash[i] = node->next_hash;
268                         if (atomic_read(&node->refcnt))
269                                 pr_crit("node %d:%d "
270                                                 "still has %d user(s)!\n",
271                                         node->tree->cnid, node->this,
272                                         atomic_read(&node->refcnt));
273                         hfs_bnode_free(node);
274                         tree->node_hash_cnt--;
275                 }
276         }
277         iput(tree->inode);
278         kfree(tree);
279 }
280
281 int hfs_btree_write(struct hfs_btree *tree)
282 {
283         struct hfs_btree_header_rec *head;
284         struct hfs_bnode *node;
285         struct page *page;
286
287         node = hfs_bnode_find(tree, 0);
288         if (IS_ERR(node))
289                 /* panic? */
290                 return -EIO;
291         /* Load the header */
292         page = node->page[0];
293         head = (struct hfs_btree_header_rec *)(kmap(page) +
294                 sizeof(struct hfs_bnode_desc));
295
296         head->root = cpu_to_be32(tree->root);
297         head->leaf_count = cpu_to_be32(tree->leaf_count);
298         head->leaf_head = cpu_to_be32(tree->leaf_head);
299         head->leaf_tail = cpu_to_be32(tree->leaf_tail);
300         head->node_count = cpu_to_be32(tree->node_count);
301         head->free_nodes = cpu_to_be32(tree->free_nodes);
302         head->attributes = cpu_to_be32(tree->attributes);
303         head->depth = cpu_to_be16(tree->depth);
304
305         kunmap(page);
306         set_page_dirty(page);
307         hfs_bnode_put(node);
308         return 0;
309 }
310
311 static struct hfs_bnode *hfs_bmap_new_bmap(struct hfs_bnode *prev, u32 idx)
312 {
313         struct hfs_btree *tree = prev->tree;
314         struct hfs_bnode *node;
315         struct hfs_bnode_desc desc;
316         __be32 cnid;
317
318         node = hfs_bnode_create(tree, idx);
319         if (IS_ERR(node))
320                 return node;
321
322         tree->free_nodes--;
323         prev->next = idx;
324         cnid = cpu_to_be32(idx);
325         hfs_bnode_write(prev, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
326
327         node->type = HFS_NODE_MAP;
328         node->num_recs = 1;
329         hfs_bnode_clear(node, 0, tree->node_size);
330         desc.next = 0;
331         desc.prev = 0;
332         desc.type = HFS_NODE_MAP;
333         desc.height = 0;
334         desc.num_recs = cpu_to_be16(1);
335         desc.reserved = 0;
336         hfs_bnode_write(node, &desc, 0, sizeof(desc));
337         hfs_bnode_write_u16(node, 14, 0x8000);
338         hfs_bnode_write_u16(node, tree->node_size - 2, 14);
339         hfs_bnode_write_u16(node, tree->node_size - 4, tree->node_size - 6);
340
341         return node;
342 }
343
344 /* Make sure @tree has enough space for the @rsvd_nodes */
345 int hfs_bmap_reserve(struct hfs_btree *tree, int rsvd_nodes)
346 {
347         struct inode *inode = tree->inode;
348         struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
349         u32 count;
350         int res;
351
352         if (rsvd_nodes <= 0)
353                 return 0;
354
355         while (tree->free_nodes < rsvd_nodes) {
356                 res = hfsplus_file_extend(inode, hfs_bnode_need_zeroout(tree));
357                 if (res)
358                         return res;
359                 hip->phys_size = inode->i_size =
360                         (loff_t)hip->alloc_blocks <<
361                                 HFSPLUS_SB(tree->sb)->alloc_blksz_shift;
362                 hip->fs_blocks =
363                         hip->alloc_blocks << HFSPLUS_SB(tree->sb)->fs_shift;
364                 inode_set_bytes(inode, inode->i_size);
365                 count = inode->i_size >> tree->node_size_shift;
366                 tree->free_nodes += count - tree->node_count;
367                 tree->node_count = count;
368         }
369         return 0;
370 }
371
372 struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree)
373 {
374         struct hfs_bnode *node, *next_node;
375         struct page **pagep;
376         u32 nidx, idx;
377         unsigned off;
378         u16 off16;
379         u16 len;
380         u8 *data, byte, m;
381         int i, res;
382
383         res = hfs_bmap_reserve(tree, 1);
384         if (res)
385                 return ERR_PTR(res);
386
387         nidx = 0;
388         node = hfs_bnode_find(tree, nidx);
389         if (IS_ERR(node))
390                 return node;
391         len = hfs_brec_lenoff(node, 2, &off16);
392         off = off16;
393
394         off += node->page_offset;
395         pagep = node->page + (off >> PAGE_SHIFT);
396         data = kmap(*pagep);
397         off &= ~PAGE_MASK;
398         idx = 0;
399
400         for (;;) {
401                 while (len) {
402                         byte = data[off];
403                         if (byte != 0xff) {
404                                 for (m = 0x80, i = 0; i < 8; m >>= 1, i++) {
405                                         if (!(byte & m)) {
406                                                 idx += i;
407                                                 data[off] |= m;
408                                                 set_page_dirty(*pagep);
409                                                 kunmap(*pagep);
410                                                 tree->free_nodes--;
411                                                 mark_inode_dirty(tree->inode);
412                                                 hfs_bnode_put(node);
413                                                 return hfs_bnode_create(tree,
414                                                         idx);
415                                         }
416                                 }
417                         }
418                         if (++off >= PAGE_SIZE) {
419                                 kunmap(*pagep);
420                                 data = kmap(*++pagep);
421                                 off = 0;
422                         }
423                         idx += 8;
424                         len--;
425                 }
426                 kunmap(*pagep);
427                 nidx = node->next;
428                 if (!nidx) {
429                         hfs_dbg(BNODE_MOD, "create new bmap node\n");
430                         next_node = hfs_bmap_new_bmap(node, idx);
431                 } else
432                         next_node = hfs_bnode_find(tree, nidx);
433                 hfs_bnode_put(node);
434                 if (IS_ERR(next_node))
435                         return next_node;
436                 node = next_node;
437
438                 len = hfs_brec_lenoff(node, 0, &off16);
439                 off = off16;
440                 off += node->page_offset;
441                 pagep = node->page + (off >> PAGE_SHIFT);
442                 data = kmap(*pagep);
443                 off &= ~PAGE_MASK;
444         }
445 }
446
447 void hfs_bmap_free(struct hfs_bnode *node)
448 {
449         struct hfs_btree *tree;
450         struct page *page;
451         u16 off, len;
452         u32 nidx;
453         u8 *data, byte, m;
454
455         hfs_dbg(BNODE_MOD, "btree_free_node: %u\n", node->this);
456         BUG_ON(!node->this);
457         tree = node->tree;
458         nidx = node->this;
459         node = hfs_bnode_find(tree, 0);
460         if (IS_ERR(node))
461                 return;
462         len = hfs_brec_lenoff(node, 2, &off);
463         while (nidx >= len * 8) {
464                 u32 i;
465
466                 nidx -= len * 8;
467                 i = node->next;
468                 if (!i) {
469                         /* panic */;
470                         pr_crit("unable to free bnode %u. "
471                                         "bmap not found!\n",
472                                 node->this);
473                         hfs_bnode_put(node);
474                         return;
475                 }
476                 hfs_bnode_put(node);
477                 node = hfs_bnode_find(tree, i);
478                 if (IS_ERR(node))
479                         return;
480                 if (node->type != HFS_NODE_MAP) {
481                         /* panic */;
482                         pr_crit("invalid bmap found! "
483                                         "(%u,%d)\n",
484                                 node->this, node->type);
485                         hfs_bnode_put(node);
486                         return;
487                 }
488                 len = hfs_brec_lenoff(node, 0, &off);
489         }
490         off += node->page_offset + nidx / 8;
491         page = node->page[off >> PAGE_SHIFT];
492         data = kmap(page);
493         off &= ~PAGE_MASK;
494         m = 1 << (~nidx & 7);
495         byte = data[off];
496         if (!(byte & m)) {
497                 pr_crit("trying to free free bnode "
498                                 "%u(%d)\n",
499                         node->this, node->type);
500                 kunmap(page);
501                 hfs_bnode_put(node);
502                 return;
503         }
504         data[off] = byte & ~m;
505         set_page_dirty(page);
506         kunmap(page);
507         hfs_bnode_put(node);
508         tree->free_nodes++;
509         mark_inode_dirty(tree->inode);
510 }