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Linux/fs/hfsplus/btree.c

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  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_CACHE_SIZE - 1) >>
240                 PAGE_CACHE_SHIFT;
241 
242         kunmap(page);
243         page_cache_release(page);
244         return tree;
245 
246  fail_page:
247         page_cache_release(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 struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree)
345 {
346         struct hfs_bnode *node, *next_node;
347         struct page **pagep;
348         u32 nidx, idx;
349         unsigned off;
350         u16 off16;
351         u16 len;
352         u8 *data, byte, m;
353         int i;
354 
355         while (!tree->free_nodes) {
356                 struct inode *inode = tree->inode;
357                 struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
358                 u32 count;
359                 int res;
360 
361                 res = hfsplus_file_extend(inode, hfs_bnode_need_zeroout(tree));
362                 if (res)
363                         return ERR_PTR(res);
364                 hip->phys_size = inode->i_size =
365                         (loff_t)hip->alloc_blocks <<
366                                 HFSPLUS_SB(tree->sb)->alloc_blksz_shift;
367                 hip->fs_blocks =
368                         hip->alloc_blocks << HFSPLUS_SB(tree->sb)->fs_shift;
369                 inode_set_bytes(inode, inode->i_size);
370                 count = inode->i_size >> tree->node_size_shift;
371                 tree->free_nodes = count - tree->node_count;
372                 tree->node_count = count;
373         }
374 
375         nidx = 0;
376         node = hfs_bnode_find(tree, nidx);
377         if (IS_ERR(node))
378                 return node;
379         len = hfs_brec_lenoff(node, 2, &off16);
380         off = off16;
381 
382         off += node->page_offset;
383         pagep = node->page + (off >> PAGE_CACHE_SHIFT);
384         data = kmap(*pagep);
385         off &= ~PAGE_CACHE_MASK;
386         idx = 0;
387 
388         for (;;) {
389                 while (len) {
390                         byte = data[off];
391                         if (byte != 0xff) {
392                                 for (m = 0x80, i = 0; i < 8; m >>= 1, i++) {
393                                         if (!(byte & m)) {
394                                                 idx += i;
395                                                 data[off] |= m;
396                                                 set_page_dirty(*pagep);
397                                                 kunmap(*pagep);
398                                                 tree->free_nodes--;
399                                                 mark_inode_dirty(tree->inode);
400                                                 hfs_bnode_put(node);
401                                                 return hfs_bnode_create(tree,
402                                                         idx);
403                                         }
404                                 }
405                         }
406                         if (++off >= PAGE_CACHE_SIZE) {
407                                 kunmap(*pagep);
408                                 data = kmap(*++pagep);
409                                 off = 0;
410                         }
411                         idx += 8;
412                         len--;
413                 }
414                 kunmap(*pagep);
415                 nidx = node->next;
416                 if (!nidx) {
417                         hfs_dbg(BNODE_MOD, "create new bmap node\n");
418                         next_node = hfs_bmap_new_bmap(node, idx);
419                 } else
420                         next_node = hfs_bnode_find(tree, nidx);
421                 hfs_bnode_put(node);
422                 if (IS_ERR(next_node))
423                         return next_node;
424                 node = next_node;
425 
426                 len = hfs_brec_lenoff(node, 0, &off16);
427                 off = off16;
428                 off += node->page_offset;
429                 pagep = node->page + (off >> PAGE_CACHE_SHIFT);
430                 data = kmap(*pagep);
431                 off &= ~PAGE_CACHE_MASK;
432         }
433 }
434 
435 void hfs_bmap_free(struct hfs_bnode *node)
436 {
437         struct hfs_btree *tree;
438         struct page *page;
439         u16 off, len;
440         u32 nidx;
441         u8 *data, byte, m;
442 
443         hfs_dbg(BNODE_MOD, "btree_free_node: %u\n", node->this);
444         BUG_ON(!node->this);
445         tree = node->tree;
446         nidx = node->this;
447         node = hfs_bnode_find(tree, 0);
448         if (IS_ERR(node))
449                 return;
450         len = hfs_brec_lenoff(node, 2, &off);
451         while (nidx >= len * 8) {
452                 u32 i;
453 
454                 nidx -= len * 8;
455                 i = node->next;
456                 hfs_bnode_put(node);
457                 if (!i) {
458                         /* panic */;
459                         pr_crit("unable to free bnode %u. "
460                                         "bmap not found!\n",
461                                 node->this);
462                         return;
463                 }
464                 node = hfs_bnode_find(tree, i);
465                 if (IS_ERR(node))
466                         return;
467                 if (node->type != HFS_NODE_MAP) {
468                         /* panic */;
469                         pr_crit("invalid bmap found! "
470                                         "(%u,%d)\n",
471                                 node->this, node->type);
472                         hfs_bnode_put(node);
473                         return;
474                 }
475                 len = hfs_brec_lenoff(node, 0, &off);
476         }
477         off += node->page_offset + nidx / 8;
478         page = node->page[off >> PAGE_CACHE_SHIFT];
479         data = kmap(page);
480         off &= ~PAGE_CACHE_MASK;
481         m = 1 << (~nidx & 7);
482         byte = data[off];
483         if (!(byte & m)) {
484                 pr_crit("trying to free free bnode "
485                                 "%u(%d)\n",
486                         node->this, node->type);
487                 kunmap(page);
488                 hfs_bnode_put(node);
489                 return;
490         }
491         data[off] = byte & ~m;
492         set_page_dirty(page);
493         kunmap(page);
494         hfs_bnode_put(node);
495         tree->free_nodes++;
496         mark_inode_dirty(tree->inode);
497 }
498 

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