summaryrefslogtreecommitdiff
path: root/fs/hfs/extent.c
blob: e33a0d36a93ebea7183909ff45f523302943b694 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
/*
 *  linux/fs/hfs/extent.c
 *
 * Copyright (C) 1995-1997  Paul H. Hargrove
 * (C) 2003 Ardis Technologies <roman@ardistech.com>
 * This file may be distributed under the terms of the GNU General Public License.
 *
 * This file contains the functions related to the extents B-tree.
 */

#include <linux/pagemap.h>

#include "hfs_fs.h"
#include "btree.h"

/*================ File-local functions ================*/

/*
 * build_key
 */
static void hfs_ext_build_key(hfs_btree_key *key, u32 cnid, u16 block, u8 type)
{
	key->key_len = 7;
	key->ext.FkType = type;
	key->ext.FNum = cpu_to_be32(cnid);
	key->ext.FABN = cpu_to_be16(block);
}

/*
 * hfs_ext_compare()
 *
 * Description:
 *   This is the comparison function used for the extents B-tree.  In
 *   comparing extent B-tree entries, the file id is the most
 *   significant field (compared as unsigned ints); the fork type is
 *   the second most significant field (compared as unsigned chars);
 *   and the allocation block number field is the least significant
 *   (compared as unsigned ints).
 * Input Variable(s):
 *   struct hfs_ext_key *key1: pointer to the first key to compare
 *   struct hfs_ext_key *key2: pointer to the second key to compare
 * Output Variable(s):
 *   NONE
 * Returns:
 *   int: negative if key1<key2, positive if key1>key2, and 0 if key1==key2
 * Preconditions:
 *   key1 and key2 point to "valid" (struct hfs_ext_key)s.
 * Postconditions:
 *   This function has no side-effects */
int hfs_ext_keycmp(const btree_key *key1, const btree_key *key2)
{
	__be32 fnum1, fnum2;
	__be16 block1, block2;

	fnum1 = key1->ext.FNum;
	fnum2 = key2->ext.FNum;
	if (fnum1 != fnum2)
		return be32_to_cpu(fnum1) < be32_to_cpu(fnum2) ? -1 : 1;
	if (key1->ext.FkType != key2->ext.FkType)
		return key1->ext.FkType < key2->ext.FkType ? -1 : 1;

	block1 = key1->ext.FABN;
	block2 = key2->ext.FABN;
	if (block1 == block2)
		return 0;
	return be16_to_cpu(block1) < be16_to_cpu(block2) ? -1 : 1;
}

/*
 * hfs_ext_find_block
 *
 * Find a block within an extent record
 */
static u16 hfs_ext_find_block(struct hfs_extent *ext, u16 off)
{
	int i;
	u16 count;

	for (i = 0; i < 3; ext++, i++) {
		count = be16_to_cpu(ext->count);
		if (off < count)
			return be16_to_cpu(ext->block) + off;
		off -= count;
	}
	/* panic? */
	return 0;
}

static int hfs_ext_block_count(struct hfs_extent *ext)
{
	int i;
	u16 count = 0;

	for (i = 0; i < 3; ext++, i++)
		count += be16_to_cpu(ext->count);
	return count;
}

static u16 hfs_ext_lastblock(struct hfs_extent *ext)
{
	int i;

	ext += 2;
	for (i = 0; i < 2; ext--, i++)
		if (ext->count)
			break;
	return be16_to_cpu(ext->block) + be16_to_cpu(ext->count);
}

static int __hfs_ext_write_extent(struct inode *inode, struct hfs_find_data *fd)
{
	int res;

	hfs_ext_build_key(fd->search_key, inode->i_ino, HFS_I(inode)->cached_start,
			  HFS_IS_RSRC(inode) ?  HFS_FK_RSRC : HFS_FK_DATA);
	res = hfs_brec_find(fd);
	if (HFS_I(inode)->flags & HFS_FLG_EXT_NEW) {
		if (res != -ENOENT)
			return res;
		hfs_brec_insert(fd, HFS_I(inode)->cached_extents, sizeof(hfs_extent_rec));
		HFS_I(inode)->flags &= ~(HFS_FLG_EXT_DIRTY|HFS_FLG_EXT_NEW);
	} else {
		if (res)
			return res;
		hfs_bnode_write(fd->bnode, HFS_I(inode)->cached_extents, fd->entryoffset, fd->entrylength);
		HFS_I(inode)->flags &= ~HFS_FLG_EXT_DIRTY;
	}
	return 0;
}

int hfs_ext_write_extent(struct inode *inode)
{
	struct hfs_find_data fd;
	int res = 0;

	if (HFS_I(inode)->flags & HFS_FLG_EXT_DIRTY) {
		res = hfs_find_init(HFS_SB(inode->i_sb)->ext_tree, &fd);
		if (res)
			return res;
		res = __hfs_ext_write_extent(inode, &fd);
		hfs_find_exit(&fd);
	}
	return res;
}

static inline int __hfs_ext_read_extent(struct hfs_find_data *fd, struct hfs_extent *extent,
					u32 cnid, u32 block, u8 type)
{
	int res;

	hfs_ext_build_key(fd->search_key, cnid, block, type);
	fd->key->ext.FNum = 0;
	res = hfs_brec_find(fd);
	if (res && res != -ENOENT)
		return res;
	if (fd->key->ext.FNum != fd->search_key->ext.FNum ||
	    fd->key->ext.FkType != fd->search_key->ext.FkType)
		return -ENOENT;
	if (fd->entrylength != sizeof(hfs_extent_rec))
		return -EIO;
	hfs_bnode_read(fd->bnode, extent, fd->entryoffset, sizeof(hfs_extent_rec));
	return 0;
}

static inline int __hfs_ext_cache_extent(struct hfs_find_data *fd, struct inode *inode, u32 block)
{
	int res;

	if (HFS_I(inode)->flags & HFS_FLG_EXT_DIRTY) {
		res = __hfs_ext_write_extent(inode, fd);
		if (res)
			return res;
	}

	res = __hfs_ext_read_extent(fd, HFS_I(inode)->cached_extents, inode->i_ino,
				    block, HFS_IS_RSRC(inode) ? HFS_FK_RSRC : HFS_FK_DATA);
	if (!res) {
		HFS_I(inode)->cached_start = be16_to_cpu(fd->key->ext.FABN);
		HFS_I(inode)->cached_blocks = hfs_ext_block_count(HFS_I(inode)->cached_extents);
	} else {
		HFS_I(inode)->cached_start = HFS_I(inode)->cached_blocks = 0;
		HFS_I(inode)->flags &= ~(HFS_FLG_EXT_DIRTY|HFS_FLG_EXT_NEW);
	}
	return res;
}

static int hfs_ext_read_extent(struct inode *inode, u16 block)
{
	struct hfs_find_data fd;
	int res;

	if (block >= HFS_I(inode)->cached_start &&
	    block < HFS_I(inode)->cached_start + HFS_I(inode)->cached_blocks)
		return 0;

	res = hfs_find_init(HFS_SB(inode->i_sb)->ext_tree, &fd);
	if (!res) {
		res = __hfs_ext_cache_extent(&fd, inode, block);
		hfs_find_exit(&fd);
	}
	return res;
}

static void hfs_dump_extent(struct hfs_extent *extent)
{
	int i;

	hfs_dbg(EXTENT, "   ");
	for (i = 0; i < 3; i++)
		hfs_dbg_cont(EXTENT, " %u:%u",
			     be16_to_cpu(extent[i].block),
			     be16_to_cpu(extent[i].count));
	hfs_dbg_cont(EXTENT, "\n");
}

static int hfs_add_extent(struct hfs_extent *extent, u16 offset,
			  u16 alloc_block, u16 block_count)
{
	u16 count, start;
	int i;

	hfs_dump_extent(extent);
	for (i = 0; i < 3; extent++, i++) {
		count = be16_to_cpu(extent->count);
		if (offset == count) {
			start = be16_to_cpu(extent->block);
			if (alloc_block != start + count) {
				if (++i >= 3)
					return -ENOSPC;
				extent++;
				extent->block = cpu_to_be16(alloc_block);
			} else
				block_count += count;
			extent->count = cpu_to_be16(block_count);
			return 0;
		} else if (offset < count)
			break;
		offset -= count;
	}
	/* panic? */
	return -EIO;
}

static int hfs_free_extents(struct super_block *sb, struct hfs_extent *extent,
			    u16 offset, u16 block_nr)
{
	u16 count, start;
	int i;

	hfs_dump_extent(extent);
	for (i = 0; i < 3; extent++, i++) {
		count = be16_to_cpu(extent->count);
		if (offset == count)
			goto found;
		else if (offset < count)
			break;
		offset -= count;
	}
	/* panic? */
	return -EIO;
found:
	for (;;) {
		start = be16_to_cpu(extent->block);
		if (count <= block_nr) {
			hfs_clear_vbm_bits(sb, start, count);
			extent->block = 0;
			extent->count = 0;
			block_nr -= count;
		} else {
			count -= block_nr;
			hfs_clear_vbm_bits(sb, start + count, block_nr);
			extent->count = cpu_to_be16(count);
			block_nr = 0;
		}
		if (!block_nr || !i)
			return 0;
		i--;
		extent--;
		count = be16_to_cpu(extent->count);
	}
}

int hfs_free_fork(struct super_block *sb, struct hfs_cat_file *file, int type)
{
	struct hfs_find_data fd;
	u32 total_blocks, blocks, start;
	u32 cnid = be32_to_cpu(file->FlNum);
	struct hfs_extent *extent;
	int res, i;

	if (type == HFS_FK_DATA) {
		total_blocks = be32_to_cpu(file->PyLen);
		extent = file->ExtRec;
	} else {
		total_blocks = be32_to_cpu(file->RPyLen);
		extent = file->RExtRec;
	}
	total_blocks /= HFS_SB(sb)->alloc_blksz;
	if (!total_blocks)
		return 0;

	blocks = 0;
	for (i = 0; i < 3; extent++, i++)
		blocks += be16_to_cpu(extent[i].count);

	res = hfs_free_extents(sb, extent, blocks, blocks);
	if (res)
		return res;
	if (total_blocks == blocks)
		return 0;

	res = hfs_find_init(HFS_SB(sb)->ext_tree, &fd);
	if (res)
		return res;
	do {
		res = __hfs_ext_read_extent(&fd, extent, cnid, total_blocks, type);
		if (res)
			break;
		start = be16_to_cpu(fd.key->ext.FABN);
		hfs_free_extents(sb, extent, total_blocks - start, total_blocks);
		hfs_brec_remove(&fd);
		total_blocks = start;
	} while (total_blocks > blocks);
	hfs_find_exit(&fd);

	return res;
}

/*
 * hfs_get_block
 */
int hfs_get_block(struct inode *inode, sector_t block,
		  struct buffer_head *bh_result, int create)
{
	struct super_block *sb;
	u16 dblock, ablock;
	int res;

	sb = inode->i_sb;
	/* Convert inode block to disk allocation block */
	ablock = (u32)block / HFS_SB(sb)->fs_div;

	if (block >= HFS_I(inode)->fs_blocks) {
		if (block > HFS_I(inode)->fs_blocks || !create)
			return -EIO;
		if (ablock >= HFS_I(inode)->alloc_blocks) {
			res = hfs_extend_file(inode);
			if (res)
				return res;
		}
	} else
		create = 0;

	if (ablock < HFS_I(inode)->first_blocks) {
		dblock = hfs_ext_find_block(HFS_I(inode)->first_extents, ablock);
		goto done;
	}

	mutex_lock(&HFS_I(inode)->extents_lock);
	res = hfs_ext_read_extent(inode, ablock);
	if (!res)
		dblock = hfs_ext_find_block(HFS_I(inode)->cached_extents,
					    ablock - HFS_I(inode)->cached_start);
	else {
		mutex_unlock(&HFS_I(inode)->extents_lock);
		return -EIO;
	}
	mutex_unlock(&HFS_I(inode)->extents_lock);

done:
	map_bh(bh_result, sb, HFS_SB(sb)->fs_start +
	       dblock * HFS_SB(sb)->fs_div +
	       (u32)block % HFS_SB(sb)->fs_div);

	if (create) {
		set_buffer_new(bh_result);
		HFS_I(inode)->phys_size += sb->s_blocksize;
		HFS_I(inode)->fs_blocks++;
		inode_add_bytes(inode, sb->s_blocksize);
		mark_inode_dirty(inode);
	}
	return 0;
}

int hfs_extend_file(struct inode *inode)
{
	struct super_block *sb = inode->i_sb;
	u32 start, len, goal;
	int res;

	mutex_lock(&HFS_I(inode)->extents_lock);
	if (HFS_I(inode)->alloc_blocks == HFS_I(inode)->first_blocks)
		goal = hfs_ext_lastblock(HFS_I(inode)->first_extents);
	else {
		res = hfs_ext_read_extent(inode, HFS_I(inode)->alloc_blocks);
		if (res)
			goto out;
		goal = hfs_ext_lastblock(HFS_I(inode)->cached_extents);
	}

	len = HFS_I(inode)->clump_blocks;
	start = hfs_vbm_search_free(sb, goal, &len);
	if (!len) {
		res = -ENOSPC;
		goto out;
	}

	hfs_dbg(EXTENT, "extend %lu: %u,%u\n", inode->i_ino, start, len);
	if (HFS_I(inode)->alloc_blocks == HFS_I(inode)->first_blocks) {
		if (!HFS_I(inode)->first_blocks) {
			hfs_dbg(EXTENT, "first extents\n");
			/* no extents yet */
			HFS_I(inode)->first_extents[0].block = cpu_to_be16(start);
			HFS_I(inode)->first_extents[0].count = cpu_to_be16(len);
			res = 0;
		} else {
			/* try to append to extents in inode */
			res = hfs_add_extent(HFS_I(inode)->first_extents,
					     HFS_I(inode)->alloc_blocks,
					     start, len);
			if (res == -ENOSPC)
				goto insert_extent;
		}
		if (!res) {
			hfs_dump_extent(HFS_I(inode)->first_extents);
			HFS_I(inode)->first_blocks += len;
		}
	} else {
		res = hfs_add_extent(HFS_I(inode)->cached_extents,
				     HFS_I(inode)->alloc_blocks -
				     HFS_I(inode)->cached_start,
				     start, len);
		if (!res) {
			hfs_dump_extent(HFS_I(inode)->cached_extents);
			HFS_I(inode)->flags |= HFS_FLG_EXT_DIRTY;
			HFS_I(inode)->cached_blocks += len;
		} else if (res == -ENOSPC)
			goto insert_extent;
	}
out:
	mutex_unlock(&HFS_I(inode)->extents_lock);
	if (!res) {
		HFS_I(inode)->alloc_blocks += len;
		mark_inode_dirty(inode);
		if (inode->i_ino < HFS_FIRSTUSER_CNID)
			set_bit(HFS_FLG_ALT_MDB_DIRTY, &HFS_SB(sb)->flags);
		set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
		hfs_mark_mdb_dirty(sb);
	}
	return res;

insert_extent:
	hfs_dbg(EXTENT, "insert new extent\n");
	res = hfs_ext_write_extent(inode);
	if (res)
		goto out;

	memset(HFS_I(inode)->cached_extents, 0, sizeof(hfs_extent_rec));
	HFS_I(inode)->cached_extents[0].block = cpu_to_be16(start);
	HFS_I(inode)->cached_extents[0].count = cpu_to_be16(len);
	hfs_dump_extent(HFS_I(inode)->cached_extents);
	HFS_I(inode)->flags |= HFS_FLG_EXT_DIRTY|HFS_FLG_EXT_NEW;
	HFS_I(inode)->cached_start = HFS_I(inode)->alloc_blocks;
	HFS_I(inode)->cached_blocks = len;

	res = 0;
	goto out;
}

void hfs_file_truncate(struct inode *inode)
{
	struct super_block *sb = inode->i_sb;
	struct hfs_find_data fd;
	u16 blk_cnt, alloc_cnt, start;
	u32 size;
	int res;

	hfs_dbg(INODE, "truncate: %lu, %Lu -> %Lu\n",
		inode->i_ino, (long long)HFS_I(inode)->phys_size,
		inode->i_size);
	if (inode->i_size > HFS_I(inode)->phys_size) {
		struct address_space *mapping = inode->i_mapping;
		void *fsdata;
		struct page *page;

		/* XXX: Can use generic_cont_expand? */
		size = inode->i_size - 1;
		res = pagecache_write_begin(NULL, mapping, size+1, 0,
				AOP_FLAG_UNINTERRUPTIBLE, &page, &fsdata);
		if (!res) {
			res = pagecache_write_end(NULL, mapping, size+1, 0, 0,
					page, fsdata);
		}
		if (res)
			inode->i_size = HFS_I(inode)->phys_size;
		return;
	} else if (inode->i_size == HFS_I(inode)->phys_size)
		return;
	size = inode->i_size + HFS_SB(sb)->alloc_blksz - 1;
	blk_cnt = size / HFS_SB(sb)->alloc_blksz;
	alloc_cnt = HFS_I(inode)->alloc_blocks;
	if (blk_cnt == alloc_cnt)
		goto out;

	mutex_lock(&HFS_I(inode)->extents_lock);
	res = hfs_find_init(HFS_SB(sb)->ext_tree, &fd);
	if (res) {
		mutex_unlock(&HFS_I(inode)->extents_lock);
		/* XXX: We lack error handling of hfs_file_truncate() */
		return;
	}
	while (1) {
		if (alloc_cnt == HFS_I(inode)->first_blocks) {
			hfs_free_extents(sb, HFS_I(inode)->first_extents,
					 alloc_cnt, alloc_cnt - blk_cnt);
			hfs_dump_extent(HFS_I(inode)->first_extents);
			HFS_I(inode)->first_blocks = blk_cnt;
			break;
		}
		res = __hfs_ext_cache_extent(&fd, inode, alloc_cnt);
		if (res)
			break;
		start = HFS_I(inode)->cached_start;
		hfs_free_extents(sb, HFS_I(inode)->cached_extents,
				 alloc_cnt - start, alloc_cnt - blk_cnt);
		hfs_dump_extent(HFS_I(inode)->cached_extents);
		if (blk_cnt > start) {
			HFS_I(inode)->flags |= HFS_FLG_EXT_DIRTY;
			break;
		}
		alloc_cnt = start;
		HFS_I(inode)->cached_start = HFS_I(inode)->cached_blocks = 0;
		HFS_I(inode)->flags &= ~(HFS_FLG_EXT_DIRTY|HFS_FLG_EXT_NEW);
		hfs_brec_remove(&fd);
	}
	hfs_find_exit(&fd);
	mutex_unlock(&HFS_I(inode)->extents_lock);

	HFS_I(inode)->alloc_blocks = blk_cnt;
out:
	HFS_I(inode)->phys_size = inode->i_size;
	HFS_I(inode)->fs_blocks = (inode->i_size + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
	inode_set_bytes(inode, HFS_I(inode)->fs_blocks << sb->s_blocksize_bits);
	mark_inode_dirty(inode);
}