1 /*
2  * balloc.c
3  *
4  * PURPOSE
5  *	Block allocation handling routines for the OSTA-UDF(tm) filesystem.
6  *
7  * COPYRIGHT
8  *	This file is distributed under the terms of the GNU General Public
9  *	License (GPL). Copies of the GPL can be obtained from:
10  *		ftp://prep.ai.mit.edu/pub/gnu/GPL
11  *	Each contributing author retains all rights to their own work.
12  *
13  *  (C) 1999-2001 Ben Fennema
14  *  (C) 1999 Stelias Computing Inc
15  *
16  * HISTORY
17  *
18  *  02/24/99 blf  Created.
19  *
20  */
21 
22 #include "udfdecl.h"
23 
24 #include <linux/buffer_head.h>
25 #include <linux/bitops.h>
26 
27 #include "udf_i.h"
28 #include "udf_sb.h"
29 
30 #define udf_clear_bit	__test_and_clear_bit_le
31 #define udf_set_bit	__test_and_set_bit_le
32 #define udf_test_bit	test_bit_le
33 #define udf_find_next_one_bit	find_next_bit_le
34 
read_block_bitmap(struct super_block * sb,struct udf_bitmap * bitmap,unsigned int block,unsigned long bitmap_nr)35 static int read_block_bitmap(struct super_block *sb,
36 			     struct udf_bitmap *bitmap, unsigned int block,
37 			     unsigned long bitmap_nr)
38 {
39 	struct buffer_head *bh = NULL;
40 	int retval = 0;
41 	struct kernel_lb_addr loc;
42 
43 	loc.logicalBlockNum = bitmap->s_extPosition;
44 	loc.partitionReferenceNum = UDF_SB(sb)->s_partition;
45 
46 	bh = udf_tread(sb, udf_get_lb_pblock(sb, &loc, block));
47 	if (!bh)
48 		retval = -EIO;
49 
50 	bitmap->s_block_bitmap[bitmap_nr] = bh;
51 	return retval;
52 }
53 
__load_block_bitmap(struct super_block * sb,struct udf_bitmap * bitmap,unsigned int block_group)54 static int __load_block_bitmap(struct super_block *sb,
55 			       struct udf_bitmap *bitmap,
56 			       unsigned int block_group)
57 {
58 	int retval = 0;
59 	int nr_groups = bitmap->s_nr_groups;
60 
61 	if (block_group >= nr_groups) {
62 		udf_debug("block_group (%d) > nr_groups (%d)\n",
63 			  block_group, nr_groups);
64 	}
65 
66 	if (bitmap->s_block_bitmap[block_group]) {
67 		return block_group;
68 	} else {
69 		retval = read_block_bitmap(sb, bitmap, block_group,
70 					   block_group);
71 		if (retval < 0)
72 			return retval;
73 		return block_group;
74 	}
75 }
76 
load_block_bitmap(struct super_block * sb,struct udf_bitmap * bitmap,unsigned int block_group)77 static inline int load_block_bitmap(struct super_block *sb,
78 				    struct udf_bitmap *bitmap,
79 				    unsigned int block_group)
80 {
81 	int slot;
82 
83 	slot = __load_block_bitmap(sb, bitmap, block_group);
84 
85 	if (slot < 0)
86 		return slot;
87 
88 	if (!bitmap->s_block_bitmap[slot])
89 		return -EIO;
90 
91 	return slot;
92 }
93 
udf_add_free_space(struct super_block * sb,u16 partition,u32 cnt)94 static void udf_add_free_space(struct super_block *sb, u16 partition, u32 cnt)
95 {
96 	struct udf_sb_info *sbi = UDF_SB(sb);
97 	struct logicalVolIntegrityDesc *lvid;
98 
99 	if (!sbi->s_lvid_bh)
100 		return;
101 
102 	lvid = (struct logicalVolIntegrityDesc *)sbi->s_lvid_bh->b_data;
103 	le32_add_cpu(&lvid->freeSpaceTable[partition], cnt);
104 	udf_updated_lvid(sb);
105 }
106 
udf_bitmap_free_blocks(struct super_block * sb,struct inode * inode,struct udf_bitmap * bitmap,struct kernel_lb_addr * bloc,uint32_t offset,uint32_t count)107 static void udf_bitmap_free_blocks(struct super_block *sb,
108 				   struct inode *inode,
109 				   struct udf_bitmap *bitmap,
110 				   struct kernel_lb_addr *bloc,
111 				   uint32_t offset,
112 				   uint32_t count)
113 {
114 	struct udf_sb_info *sbi = UDF_SB(sb);
115 	struct buffer_head *bh = NULL;
116 	struct udf_part_map *partmap;
117 	unsigned long block;
118 	unsigned long block_group;
119 	unsigned long bit;
120 	unsigned long i;
121 	int bitmap_nr;
122 	unsigned long overflow;
123 
124 	mutex_lock(&sbi->s_alloc_mutex);
125 	partmap = &sbi->s_partmaps[bloc->partitionReferenceNum];
126 	if (bloc->logicalBlockNum + count < count ||
127 	    (bloc->logicalBlockNum + count) > partmap->s_partition_len) {
128 		udf_debug("%d < %d || %d + %d > %d\n",
129 			  bloc->logicalBlockNum, 0,
130 			  bloc->logicalBlockNum, count,
131 			  partmap->s_partition_len);
132 		goto error_return;
133 	}
134 
135 	block = bloc->logicalBlockNum + offset +
136 		(sizeof(struct spaceBitmapDesc) << 3);
137 
138 	do {
139 		overflow = 0;
140 		block_group = block >> (sb->s_blocksize_bits + 3);
141 		bit = block % (sb->s_blocksize << 3);
142 
143 		/*
144 		* Check to see if we are freeing blocks across a group boundary.
145 		*/
146 		if (bit + count > (sb->s_blocksize << 3)) {
147 			overflow = bit + count - (sb->s_blocksize << 3);
148 			count -= overflow;
149 		}
150 		bitmap_nr = load_block_bitmap(sb, bitmap, block_group);
151 		if (bitmap_nr < 0)
152 			goto error_return;
153 
154 		bh = bitmap->s_block_bitmap[bitmap_nr];
155 		for (i = 0; i < count; i++) {
156 			if (udf_set_bit(bit + i, bh->b_data)) {
157 				udf_debug("bit %ld already set\n", bit + i);
158 				udf_debug("byte=%2x\n",
159 					  ((char *)bh->b_data)[(bit + i) >> 3]);
160 			}
161 		}
162 		udf_add_free_space(sb, sbi->s_partition, count);
163 		mark_buffer_dirty(bh);
164 		if (overflow) {
165 			block += count;
166 			count = overflow;
167 		}
168 	} while (overflow);
169 
170 error_return:
171 	mutex_unlock(&sbi->s_alloc_mutex);
172 }
173 
udf_bitmap_prealloc_blocks(struct super_block * sb,struct inode * inode,struct udf_bitmap * bitmap,uint16_t partition,uint32_t first_block,uint32_t block_count)174 static int udf_bitmap_prealloc_blocks(struct super_block *sb,
175 				      struct inode *inode,
176 				      struct udf_bitmap *bitmap,
177 				      uint16_t partition, uint32_t first_block,
178 				      uint32_t block_count)
179 {
180 	struct udf_sb_info *sbi = UDF_SB(sb);
181 	int alloc_count = 0;
182 	int bit, block, block_group, group_start;
183 	int nr_groups, bitmap_nr;
184 	struct buffer_head *bh;
185 	__u32 part_len;
186 
187 	mutex_lock(&sbi->s_alloc_mutex);
188 	part_len = sbi->s_partmaps[partition].s_partition_len;
189 	if (first_block >= part_len)
190 		goto out;
191 
192 	if (first_block + block_count > part_len)
193 		block_count = part_len - first_block;
194 
195 	do {
196 		nr_groups = udf_compute_nr_groups(sb, partition);
197 		block = first_block + (sizeof(struct spaceBitmapDesc) << 3);
198 		block_group = block >> (sb->s_blocksize_bits + 3);
199 		group_start = block_group ? 0 : sizeof(struct spaceBitmapDesc);
200 
201 		bitmap_nr = load_block_bitmap(sb, bitmap, block_group);
202 		if (bitmap_nr < 0)
203 			goto out;
204 		bh = bitmap->s_block_bitmap[bitmap_nr];
205 
206 		bit = block % (sb->s_blocksize << 3);
207 
208 		while (bit < (sb->s_blocksize << 3) && block_count > 0) {
209 			if (!udf_clear_bit(bit, bh->b_data))
210 				goto out;
211 			block_count--;
212 			alloc_count++;
213 			bit++;
214 			block++;
215 		}
216 		mark_buffer_dirty(bh);
217 	} while (block_count > 0);
218 
219 out:
220 	udf_add_free_space(sb, partition, -alloc_count);
221 	mutex_unlock(&sbi->s_alloc_mutex);
222 	return alloc_count;
223 }
224 
udf_bitmap_new_block(struct super_block * sb,struct inode * inode,struct udf_bitmap * bitmap,uint16_t partition,uint32_t goal,int * err)225 static int udf_bitmap_new_block(struct super_block *sb,
226 				struct inode *inode,
227 				struct udf_bitmap *bitmap, uint16_t partition,
228 				uint32_t goal, int *err)
229 {
230 	struct udf_sb_info *sbi = UDF_SB(sb);
231 	int newbit, bit = 0, block, block_group, group_start;
232 	int end_goal, nr_groups, bitmap_nr, i;
233 	struct buffer_head *bh = NULL;
234 	char *ptr;
235 	int newblock = 0;
236 
237 	*err = -ENOSPC;
238 	mutex_lock(&sbi->s_alloc_mutex);
239 
240 repeat:
241 	if (goal >= sbi->s_partmaps[partition].s_partition_len)
242 		goal = 0;
243 
244 	nr_groups = bitmap->s_nr_groups;
245 	block = goal + (sizeof(struct spaceBitmapDesc) << 3);
246 	block_group = block >> (sb->s_blocksize_bits + 3);
247 	group_start = block_group ? 0 : sizeof(struct spaceBitmapDesc);
248 
249 	bitmap_nr = load_block_bitmap(sb, bitmap, block_group);
250 	if (bitmap_nr < 0)
251 		goto error_return;
252 	bh = bitmap->s_block_bitmap[bitmap_nr];
253 	ptr = memscan((char *)bh->b_data + group_start, 0xFF,
254 		      sb->s_blocksize - group_start);
255 
256 	if ((ptr - ((char *)bh->b_data)) < sb->s_blocksize) {
257 		bit = block % (sb->s_blocksize << 3);
258 		if (udf_test_bit(bit, bh->b_data))
259 			goto got_block;
260 
261 		end_goal = (bit + 63) & ~63;
262 		bit = udf_find_next_one_bit(bh->b_data, end_goal, bit);
263 		if (bit < end_goal)
264 			goto got_block;
265 
266 		ptr = memscan((char *)bh->b_data + (bit >> 3), 0xFF,
267 			      sb->s_blocksize - ((bit + 7) >> 3));
268 		newbit = (ptr - ((char *)bh->b_data)) << 3;
269 		if (newbit < sb->s_blocksize << 3) {
270 			bit = newbit;
271 			goto search_back;
272 		}
273 
274 		newbit = udf_find_next_one_bit(bh->b_data,
275 					       sb->s_blocksize << 3, bit);
276 		if (newbit < sb->s_blocksize << 3) {
277 			bit = newbit;
278 			goto got_block;
279 		}
280 	}
281 
282 	for (i = 0; i < (nr_groups * 2); i++) {
283 		block_group++;
284 		if (block_group >= nr_groups)
285 			block_group = 0;
286 		group_start = block_group ? 0 : sizeof(struct spaceBitmapDesc);
287 
288 		bitmap_nr = load_block_bitmap(sb, bitmap, block_group);
289 		if (bitmap_nr < 0)
290 			goto error_return;
291 		bh = bitmap->s_block_bitmap[bitmap_nr];
292 		if (i < nr_groups) {
293 			ptr = memscan((char *)bh->b_data + group_start, 0xFF,
294 				      sb->s_blocksize - group_start);
295 			if ((ptr - ((char *)bh->b_data)) < sb->s_blocksize) {
296 				bit = (ptr - ((char *)bh->b_data)) << 3;
297 				break;
298 			}
299 		} else {
300 			bit = udf_find_next_one_bit(bh->b_data,
301 						    sb->s_blocksize << 3,
302 						    group_start << 3);
303 			if (bit < sb->s_blocksize << 3)
304 				break;
305 		}
306 	}
307 	if (i >= (nr_groups * 2)) {
308 		mutex_unlock(&sbi->s_alloc_mutex);
309 		return newblock;
310 	}
311 	if (bit < sb->s_blocksize << 3)
312 		goto search_back;
313 	else
314 		bit = udf_find_next_one_bit(bh->b_data, sb->s_blocksize << 3,
315 					    group_start << 3);
316 	if (bit >= sb->s_blocksize << 3) {
317 		mutex_unlock(&sbi->s_alloc_mutex);
318 		return 0;
319 	}
320 
321 search_back:
322 	i = 0;
323 	while (i < 7 && bit > (group_start << 3) &&
324 	       udf_test_bit(bit - 1, bh->b_data)) {
325 		++i;
326 		--bit;
327 	}
328 
329 got_block:
330 	newblock = bit + (block_group << (sb->s_blocksize_bits + 3)) -
331 		(sizeof(struct spaceBitmapDesc) << 3);
332 
333 	if (!udf_clear_bit(bit, bh->b_data)) {
334 		udf_debug("bit already cleared for block %d\n", bit);
335 		goto repeat;
336 	}
337 
338 	mark_buffer_dirty(bh);
339 
340 	udf_add_free_space(sb, partition, -1);
341 	mutex_unlock(&sbi->s_alloc_mutex);
342 	*err = 0;
343 	return newblock;
344 
345 error_return:
346 	*err = -EIO;
347 	mutex_unlock(&sbi->s_alloc_mutex);
348 	return 0;
349 }
350 
udf_table_free_blocks(struct super_block * sb,struct inode * inode,struct inode * table,struct kernel_lb_addr * bloc,uint32_t offset,uint32_t count)351 static void udf_table_free_blocks(struct super_block *sb,
352 				  struct inode *inode,
353 				  struct inode *table,
354 				  struct kernel_lb_addr *bloc,
355 				  uint32_t offset,
356 				  uint32_t count)
357 {
358 	struct udf_sb_info *sbi = UDF_SB(sb);
359 	struct udf_part_map *partmap;
360 	uint32_t start, end;
361 	uint32_t elen;
362 	struct kernel_lb_addr eloc;
363 	struct extent_position oepos, epos;
364 	int8_t etype;
365 	int i;
366 	struct udf_inode_info *iinfo;
367 
368 	mutex_lock(&sbi->s_alloc_mutex);
369 	partmap = &sbi->s_partmaps[bloc->partitionReferenceNum];
370 	if (bloc->logicalBlockNum + count < count ||
371 	    (bloc->logicalBlockNum + count) > partmap->s_partition_len) {
372 		udf_debug("%d < %d || %d + %d > %d\n",
373 			  bloc->logicalBlockNum, 0,
374 			  bloc->logicalBlockNum, count,
375 			  partmap->s_partition_len);
376 		goto error_return;
377 	}
378 
379 	iinfo = UDF_I(table);
380 	udf_add_free_space(sb, sbi->s_partition, count);
381 
382 	start = bloc->logicalBlockNum + offset;
383 	end = bloc->logicalBlockNum + offset + count - 1;
384 
385 	epos.offset = oepos.offset = sizeof(struct unallocSpaceEntry);
386 	elen = 0;
387 	epos.block = oepos.block = iinfo->i_location;
388 	epos.bh = oepos.bh = NULL;
389 
390 	while (count &&
391 	       (etype = udf_next_aext(table, &epos, &eloc, &elen, 1)) != -1) {
392 		if (((eloc.logicalBlockNum +
393 			(elen >> sb->s_blocksize_bits)) == start)) {
394 			if ((0x3FFFFFFF - elen) <
395 					(count << sb->s_blocksize_bits)) {
396 				uint32_t tmp = ((0x3FFFFFFF - elen) >>
397 							sb->s_blocksize_bits);
398 				count -= tmp;
399 				start += tmp;
400 				elen = (etype << 30) |
401 					(0x40000000 - sb->s_blocksize);
402 			} else {
403 				elen = (etype << 30) |
404 					(elen +
405 					(count << sb->s_blocksize_bits));
406 				start += count;
407 				count = 0;
408 			}
409 			udf_write_aext(table, &oepos, &eloc, elen, 1);
410 		} else if (eloc.logicalBlockNum == (end + 1)) {
411 			if ((0x3FFFFFFF - elen) <
412 					(count << sb->s_blocksize_bits)) {
413 				uint32_t tmp = ((0x3FFFFFFF - elen) >>
414 						sb->s_blocksize_bits);
415 				count -= tmp;
416 				end -= tmp;
417 				eloc.logicalBlockNum -= tmp;
418 				elen = (etype << 30) |
419 					(0x40000000 - sb->s_blocksize);
420 			} else {
421 				eloc.logicalBlockNum = start;
422 				elen = (etype << 30) |
423 					(elen +
424 					(count << sb->s_blocksize_bits));
425 				end -= count;
426 				count = 0;
427 			}
428 			udf_write_aext(table, &oepos, &eloc, elen, 1);
429 		}
430 
431 		if (epos.bh != oepos.bh) {
432 			i = -1;
433 			oepos.block = epos.block;
434 			brelse(oepos.bh);
435 			get_bh(epos.bh);
436 			oepos.bh = epos.bh;
437 			oepos.offset = 0;
438 		} else {
439 			oepos.offset = epos.offset;
440 		}
441 	}
442 
443 	if (count) {
444 		/*
445 		 * NOTE: we CANNOT use udf_add_aext here, as it can try to
446 		 * allocate a new block, and since we hold the super block
447 		 * lock already very bad things would happen :)
448 		 *
449 		 * We copy the behavior of udf_add_aext, but instead of
450 		 * trying to allocate a new block close to the existing one,
451 		 * we just steal a block from the extent we are trying to add.
452 		 *
453 		 * It would be nice if the blocks were close together, but it
454 		 * isn't required.
455 		 */
456 
457 		int adsize;
458 		struct short_ad *sad = NULL;
459 		struct long_ad *lad = NULL;
460 		struct allocExtDesc *aed;
461 
462 		eloc.logicalBlockNum = start;
463 		elen = EXT_RECORDED_ALLOCATED |
464 			(count << sb->s_blocksize_bits);
465 
466 		if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
467 			adsize = sizeof(struct short_ad);
468 		else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
469 			adsize = sizeof(struct long_ad);
470 		else {
471 			brelse(oepos.bh);
472 			brelse(epos.bh);
473 			goto error_return;
474 		}
475 
476 		if (epos.offset + (2 * adsize) > sb->s_blocksize) {
477 			unsigned char *sptr, *dptr;
478 			int loffset;
479 
480 			brelse(oepos.bh);
481 			oepos = epos;
482 
483 			/* Steal a block from the extent being free'd */
484 			epos.block.logicalBlockNum = eloc.logicalBlockNum;
485 			eloc.logicalBlockNum++;
486 			elen -= sb->s_blocksize;
487 
488 			epos.bh = udf_tread(sb,
489 					udf_get_lb_pblock(sb, &epos.block, 0));
490 			if (!epos.bh) {
491 				brelse(oepos.bh);
492 				goto error_return;
493 			}
494 			aed = (struct allocExtDesc *)(epos.bh->b_data);
495 			aed->previousAllocExtLocation =
496 				cpu_to_le32(oepos.block.logicalBlockNum);
497 			if (epos.offset + adsize > sb->s_blocksize) {
498 				loffset = epos.offset;
499 				aed->lengthAllocDescs = cpu_to_le32(adsize);
500 				sptr = iinfo->i_ext.i_data + epos.offset
501 								- adsize;
502 				dptr = epos.bh->b_data +
503 					sizeof(struct allocExtDesc);
504 				memcpy(dptr, sptr, adsize);
505 				epos.offset = sizeof(struct allocExtDesc) +
506 						adsize;
507 			} else {
508 				loffset = epos.offset + adsize;
509 				aed->lengthAllocDescs = cpu_to_le32(0);
510 				if (oepos.bh) {
511 					sptr = oepos.bh->b_data + epos.offset;
512 					aed = (struct allocExtDesc *)
513 						oepos.bh->b_data;
514 					le32_add_cpu(&aed->lengthAllocDescs,
515 							adsize);
516 				} else {
517 					sptr = iinfo->i_ext.i_data +
518 								epos.offset;
519 					iinfo->i_lenAlloc += adsize;
520 					mark_inode_dirty(table);
521 				}
522 				epos.offset = sizeof(struct allocExtDesc);
523 			}
524 			if (sbi->s_udfrev >= 0x0200)
525 				udf_new_tag(epos.bh->b_data, TAG_IDENT_AED,
526 					    3, 1, epos.block.logicalBlockNum,
527 					    sizeof(struct tag));
528 			else
529 				udf_new_tag(epos.bh->b_data, TAG_IDENT_AED,
530 					    2, 1, epos.block.logicalBlockNum,
531 					    sizeof(struct tag));
532 
533 			switch (iinfo->i_alloc_type) {
534 			case ICBTAG_FLAG_AD_SHORT:
535 				sad = (struct short_ad *)sptr;
536 				sad->extLength = cpu_to_le32(
537 					EXT_NEXT_EXTENT_ALLOCDECS |
538 					sb->s_blocksize);
539 				sad->extPosition =
540 					cpu_to_le32(epos.block.logicalBlockNum);
541 				break;
542 			case ICBTAG_FLAG_AD_LONG:
543 				lad = (struct long_ad *)sptr;
544 				lad->extLength = cpu_to_le32(
545 					EXT_NEXT_EXTENT_ALLOCDECS |
546 					sb->s_blocksize);
547 				lad->extLocation =
548 					cpu_to_lelb(epos.block);
549 				break;
550 			}
551 			if (oepos.bh) {
552 				udf_update_tag(oepos.bh->b_data, loffset);
553 				mark_buffer_dirty(oepos.bh);
554 			} else {
555 				mark_inode_dirty(table);
556 			}
557 		}
558 
559 		/* It's possible that stealing the block emptied the extent */
560 		if (elen) {
561 			udf_write_aext(table, &epos, &eloc, elen, 1);
562 
563 			if (!epos.bh) {
564 				iinfo->i_lenAlloc += adsize;
565 				mark_inode_dirty(table);
566 			} else {
567 				aed = (struct allocExtDesc *)epos.bh->b_data;
568 				le32_add_cpu(&aed->lengthAllocDescs, adsize);
569 				udf_update_tag(epos.bh->b_data, epos.offset);
570 				mark_buffer_dirty(epos.bh);
571 			}
572 		}
573 	}
574 
575 	brelse(epos.bh);
576 	brelse(oepos.bh);
577 
578 error_return:
579 	mutex_unlock(&sbi->s_alloc_mutex);
580 	return;
581 }
582 
udf_table_prealloc_blocks(struct super_block * sb,struct inode * inode,struct inode * table,uint16_t partition,uint32_t first_block,uint32_t block_count)583 static int udf_table_prealloc_blocks(struct super_block *sb,
584 				     struct inode *inode,
585 				     struct inode *table, uint16_t partition,
586 				     uint32_t first_block, uint32_t block_count)
587 {
588 	struct udf_sb_info *sbi = UDF_SB(sb);
589 	int alloc_count = 0;
590 	uint32_t elen, adsize;
591 	struct kernel_lb_addr eloc;
592 	struct extent_position epos;
593 	int8_t etype = -1;
594 	struct udf_inode_info *iinfo;
595 
596 	if (first_block >= sbi->s_partmaps[partition].s_partition_len)
597 		return 0;
598 
599 	iinfo = UDF_I(table);
600 	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
601 		adsize = sizeof(struct short_ad);
602 	else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
603 		adsize = sizeof(struct long_ad);
604 	else
605 		return 0;
606 
607 	mutex_lock(&sbi->s_alloc_mutex);
608 	epos.offset = sizeof(struct unallocSpaceEntry);
609 	epos.block = iinfo->i_location;
610 	epos.bh = NULL;
611 	eloc.logicalBlockNum = 0xFFFFFFFF;
612 
613 	while (first_block != eloc.logicalBlockNum &&
614 	       (etype = udf_next_aext(table, &epos, &eloc, &elen, 1)) != -1) {
615 		udf_debug("eloc=%d, elen=%d, first_block=%d\n",
616 			  eloc.logicalBlockNum, elen, first_block);
617 		; /* empty loop body */
618 	}
619 
620 	if (first_block == eloc.logicalBlockNum) {
621 		epos.offset -= adsize;
622 
623 		alloc_count = (elen >> sb->s_blocksize_bits);
624 		if (alloc_count > block_count) {
625 			alloc_count = block_count;
626 			eloc.logicalBlockNum += alloc_count;
627 			elen -= (alloc_count << sb->s_blocksize_bits);
628 			udf_write_aext(table, &epos, &eloc,
629 					(etype << 30) | elen, 1);
630 		} else
631 			udf_delete_aext(table, epos, eloc,
632 					(etype << 30) | elen);
633 	} else {
634 		alloc_count = 0;
635 	}
636 
637 	brelse(epos.bh);
638 
639 	if (alloc_count)
640 		udf_add_free_space(sb, partition, -alloc_count);
641 	mutex_unlock(&sbi->s_alloc_mutex);
642 	return alloc_count;
643 }
644 
udf_table_new_block(struct super_block * sb,struct inode * inode,struct inode * table,uint16_t partition,uint32_t goal,int * err)645 static int udf_table_new_block(struct super_block *sb,
646 			       struct inode *inode,
647 			       struct inode *table, uint16_t partition,
648 			       uint32_t goal, int *err)
649 {
650 	struct udf_sb_info *sbi = UDF_SB(sb);
651 	uint32_t spread = 0xFFFFFFFF, nspread = 0xFFFFFFFF;
652 	uint32_t newblock = 0, adsize;
653 	uint32_t elen, goal_elen = 0;
654 	struct kernel_lb_addr eloc, uninitialized_var(goal_eloc);
655 	struct extent_position epos, goal_epos;
656 	int8_t etype;
657 	struct udf_inode_info *iinfo = UDF_I(table);
658 
659 	*err = -ENOSPC;
660 
661 	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
662 		adsize = sizeof(struct short_ad);
663 	else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
664 		adsize = sizeof(struct long_ad);
665 	else
666 		return newblock;
667 
668 	mutex_lock(&sbi->s_alloc_mutex);
669 	if (goal >= sbi->s_partmaps[partition].s_partition_len)
670 		goal = 0;
671 
672 	/* We search for the closest matching block to goal. If we find
673 	   a exact hit, we stop. Otherwise we keep going till we run out
674 	   of extents. We store the buffer_head, bloc, and extoffset
675 	   of the current closest match and use that when we are done.
676 	 */
677 	epos.offset = sizeof(struct unallocSpaceEntry);
678 	epos.block = iinfo->i_location;
679 	epos.bh = goal_epos.bh = NULL;
680 
681 	while (spread &&
682 	       (etype = udf_next_aext(table, &epos, &eloc, &elen, 1)) != -1) {
683 		if (goal >= eloc.logicalBlockNum) {
684 			if (goal < eloc.logicalBlockNum +
685 					(elen >> sb->s_blocksize_bits))
686 				nspread = 0;
687 			else
688 				nspread = goal - eloc.logicalBlockNum -
689 					(elen >> sb->s_blocksize_bits);
690 		} else {
691 			nspread = eloc.logicalBlockNum - goal;
692 		}
693 
694 		if (nspread < spread) {
695 			spread = nspread;
696 			if (goal_epos.bh != epos.bh) {
697 				brelse(goal_epos.bh);
698 				goal_epos.bh = epos.bh;
699 				get_bh(goal_epos.bh);
700 			}
701 			goal_epos.block = epos.block;
702 			goal_epos.offset = epos.offset - adsize;
703 			goal_eloc = eloc;
704 			goal_elen = (etype << 30) | elen;
705 		}
706 	}
707 
708 	brelse(epos.bh);
709 
710 	if (spread == 0xFFFFFFFF) {
711 		brelse(goal_epos.bh);
712 		mutex_unlock(&sbi->s_alloc_mutex);
713 		return 0;
714 	}
715 
716 	/* Only allocate blocks from the beginning of the extent.
717 	   That way, we only delete (empty) extents, never have to insert an
718 	   extent because of splitting */
719 	/* This works, but very poorly.... */
720 
721 	newblock = goal_eloc.logicalBlockNum;
722 	goal_eloc.logicalBlockNum++;
723 	goal_elen -= sb->s_blocksize;
724 
725 	if (goal_elen)
726 		udf_write_aext(table, &goal_epos, &goal_eloc, goal_elen, 1);
727 	else
728 		udf_delete_aext(table, goal_epos, goal_eloc, goal_elen);
729 	brelse(goal_epos.bh);
730 
731 	udf_add_free_space(sb, partition, -1);
732 
733 	mutex_unlock(&sbi->s_alloc_mutex);
734 	*err = 0;
735 	return newblock;
736 }
737 
udf_free_blocks(struct super_block * sb,struct inode * inode,struct kernel_lb_addr * bloc,uint32_t offset,uint32_t count)738 void udf_free_blocks(struct super_block *sb, struct inode *inode,
739 		     struct kernel_lb_addr *bloc, uint32_t offset,
740 		     uint32_t count)
741 {
742 	uint16_t partition = bloc->partitionReferenceNum;
743 	struct udf_part_map *map = &UDF_SB(sb)->s_partmaps[partition];
744 
745 	if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_BITMAP) {
746 		udf_bitmap_free_blocks(sb, inode, map->s_uspace.s_bitmap,
747 				       bloc, offset, count);
748 	} else if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_TABLE) {
749 		udf_table_free_blocks(sb, inode, map->s_uspace.s_table,
750 				      bloc, offset, count);
751 	} else if (map->s_partition_flags & UDF_PART_FLAG_FREED_BITMAP) {
752 		udf_bitmap_free_blocks(sb, inode, map->s_fspace.s_bitmap,
753 				       bloc, offset, count);
754 	} else if (map->s_partition_flags & UDF_PART_FLAG_FREED_TABLE) {
755 		udf_table_free_blocks(sb, inode, map->s_fspace.s_table,
756 				      bloc, offset, count);
757 	}
758 }
759 
udf_prealloc_blocks(struct super_block * sb,struct inode * inode,uint16_t partition,uint32_t first_block,uint32_t block_count)760 inline int udf_prealloc_blocks(struct super_block *sb,
761 			       struct inode *inode,
762 			       uint16_t partition, uint32_t first_block,
763 			       uint32_t block_count)
764 {
765 	struct udf_part_map *map = &UDF_SB(sb)->s_partmaps[partition];
766 
767 	if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_BITMAP)
768 		return udf_bitmap_prealloc_blocks(sb, inode,
769 						  map->s_uspace.s_bitmap,
770 						  partition, first_block,
771 						  block_count);
772 	else if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_TABLE)
773 		return udf_table_prealloc_blocks(sb, inode,
774 						 map->s_uspace.s_table,
775 						 partition, first_block,
776 						 block_count);
777 	else if (map->s_partition_flags & UDF_PART_FLAG_FREED_BITMAP)
778 		return udf_bitmap_prealloc_blocks(sb, inode,
779 						  map->s_fspace.s_bitmap,
780 						  partition, first_block,
781 						  block_count);
782 	else if (map->s_partition_flags & UDF_PART_FLAG_FREED_TABLE)
783 		return udf_table_prealloc_blocks(sb, inode,
784 						 map->s_fspace.s_table,
785 						 partition, first_block,
786 						 block_count);
787 	else
788 		return 0;
789 }
790 
udf_new_block(struct super_block * sb,struct inode * inode,uint16_t partition,uint32_t goal,int * err)791 inline int udf_new_block(struct super_block *sb,
792 			 struct inode *inode,
793 			 uint16_t partition, uint32_t goal, int *err)
794 {
795 	struct udf_part_map *map = &UDF_SB(sb)->s_partmaps[partition];
796 
797 	if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_BITMAP)
798 		return udf_bitmap_new_block(sb, inode,
799 					   map->s_uspace.s_bitmap,
800 					   partition, goal, err);
801 	else if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_TABLE)
802 		return udf_table_new_block(sb, inode,
803 					   map->s_uspace.s_table,
804 					   partition, goal, err);
805 	else if (map->s_partition_flags & UDF_PART_FLAG_FREED_BITMAP)
806 		return udf_bitmap_new_block(sb, inode,
807 					    map->s_fspace.s_bitmap,
808 					    partition, goal, err);
809 	else if (map->s_partition_flags & UDF_PART_FLAG_FREED_TABLE)
810 		return udf_table_new_block(sb, inode,
811 					   map->s_fspace.s_table,
812 					   partition, goal, err);
813 	else {
814 		*err = -EIO;
815 		return 0;
816 	}
817 }
818