xref: /openbmc/linux/fs/udf/balloc.c (revision 3a065fcf)
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/quotaops.h>
25 #include <linux/buffer_head.h>
26 #include <linux/bitops.h>
27 
28 #include "udf_i.h"
29 #include "udf_sb.h"
30 
31 #define udf_clear_bit(nr, addr) ext2_clear_bit(nr, addr)
32 #define udf_set_bit(nr, addr) ext2_set_bit(nr, addr)
33 #define udf_test_bit(nr, addr) ext2_test_bit(nr, addr)
34 #define udf_find_next_one_bit(addr, size, offset) \
35 		ext2_find_next_bit(addr, size, offset)
36 
37 static int read_block_bitmap(struct super_block *sb,
38 			     struct udf_bitmap *bitmap, unsigned int block,
39 			     unsigned long bitmap_nr)
40 {
41 	struct buffer_head *bh = NULL;
42 	int retval = 0;
43 	struct kernel_lb_addr loc;
44 
45 	loc.logicalBlockNum = bitmap->s_extPosition;
46 	loc.partitionReferenceNum = UDF_SB(sb)->s_partition;
47 
48 	bh = udf_tread(sb, udf_get_lb_pblock(sb, &loc, block));
49 	if (!bh)
50 		retval = -EIO;
51 
52 	bitmap->s_block_bitmap[bitmap_nr] = bh;
53 	return retval;
54 }
55 
56 static int __load_block_bitmap(struct super_block *sb,
57 			       struct udf_bitmap *bitmap,
58 			       unsigned int block_group)
59 {
60 	int retval = 0;
61 	int nr_groups = bitmap->s_nr_groups;
62 
63 	if (block_group >= nr_groups) {
64 		udf_debug("block_group (%d) > nr_groups (%d)\n", block_group,
65 			  nr_groups);
66 	}
67 
68 	if (bitmap->s_block_bitmap[block_group]) {
69 		return block_group;
70 	} else {
71 		retval = read_block_bitmap(sb, bitmap, block_group,
72 					   block_group);
73 		if (retval < 0)
74 			return retval;
75 		return block_group;
76 	}
77 }
78 
79 static inline int load_block_bitmap(struct super_block *sb,
80 				    struct udf_bitmap *bitmap,
81 				    unsigned int block_group)
82 {
83 	int slot;
84 
85 	slot = __load_block_bitmap(sb, bitmap, block_group);
86 
87 	if (slot < 0)
88 		return slot;
89 
90 	if (!bitmap->s_block_bitmap[slot])
91 		return -EIO;
92 
93 	return slot;
94 }
95 
96 static void udf_add_free_space(struct super_block *sb, u16 partition, u32 cnt)
97 {
98 	struct udf_sb_info *sbi = UDF_SB(sb);
99 	struct logicalVolIntegrityDesc *lvid;
100 
101 	if (!sbi->s_lvid_bh)
102 		return;
103 
104 	lvid = (struct logicalVolIntegrityDesc *)sbi->s_lvid_bh->b_data;
105 	le32_add_cpu(&lvid->freeSpaceTable[partition], cnt);
106 	udf_updated_lvid(sb);
107 }
108 
109 static void udf_bitmap_free_blocks(struct super_block *sb,
110 				   struct inode *inode,
111 				   struct udf_bitmap *bitmap,
112 				   struct kernel_lb_addr *bloc,
113 				   uint32_t offset,
114 				   uint32_t count)
115 {
116 	struct udf_sb_info *sbi = UDF_SB(sb);
117 	struct buffer_head *bh = NULL;
118 	struct udf_part_map *partmap;
119 	unsigned long block;
120 	unsigned long block_group;
121 	unsigned long bit;
122 	unsigned long i;
123 	int bitmap_nr;
124 	unsigned long overflow;
125 
126 	mutex_lock(&sbi->s_alloc_mutex);
127 	partmap = &sbi->s_partmaps[bloc->partitionReferenceNum];
128 	if (bloc->logicalBlockNum < 0 ||
129 	    (bloc->logicalBlockNum + count) >
130 		partmap->s_partition_len) {
131 		udf_debug("%d < %d || %d + %d > %d\n",
132 			  bloc->logicalBlockNum, 0, bloc->logicalBlockNum,
133 			  count, partmap->s_partition_len);
134 		goto error_return;
135 	}
136 
137 	block = bloc->logicalBlockNum + offset +
138 		(sizeof(struct spaceBitmapDesc) << 3);
139 
140 	do {
141 		overflow = 0;
142 		block_group = block >> (sb->s_blocksize_bits + 3);
143 		bit = block % (sb->s_blocksize << 3);
144 
145 		/*
146 		* Check to see if we are freeing blocks across a group boundary.
147 		*/
148 		if (bit + count > (sb->s_blocksize << 3)) {
149 			overflow = bit + count - (sb->s_blocksize << 3);
150 			count -= overflow;
151 		}
152 		bitmap_nr = load_block_bitmap(sb, bitmap, block_group);
153 		if (bitmap_nr < 0)
154 			goto error_return;
155 
156 		bh = bitmap->s_block_bitmap[bitmap_nr];
157 		for (i = 0; i < count; i++) {
158 			if (udf_set_bit(bit + i, bh->b_data)) {
159 				udf_debug("bit %ld already set\n", bit + i);
160 				udf_debug("byte=%2x\n",
161 					((char *)bh->b_data)[(bit + i) >> 3]);
162 			} else {
163 				if (inode)
164 					dquot_free_block(inode, 1);
165 				udf_add_free_space(sb, sbi->s_partition, 1);
166 			}
167 		}
168 		mark_buffer_dirty(bh);
169 		if (overflow) {
170 			block += count;
171 			count = overflow;
172 		}
173 	} while (overflow);
174 
175 error_return:
176 	mutex_unlock(&sbi->s_alloc_mutex);
177 }
178 
179 static int udf_bitmap_prealloc_blocks(struct super_block *sb,
180 				      struct inode *inode,
181 				      struct udf_bitmap *bitmap,
182 				      uint16_t partition, uint32_t first_block,
183 				      uint32_t block_count)
184 {
185 	struct udf_sb_info *sbi = UDF_SB(sb);
186 	int alloc_count = 0;
187 	int bit, block, block_group, group_start;
188 	int nr_groups, bitmap_nr;
189 	struct buffer_head *bh;
190 	__u32 part_len;
191 
192 	mutex_lock(&sbi->s_alloc_mutex);
193 	part_len = sbi->s_partmaps[partition].s_partition_len;
194 	if (first_block >= part_len)
195 		goto out;
196 
197 	if (first_block + block_count > part_len)
198 		block_count = part_len - first_block;
199 
200 	do {
201 		nr_groups = udf_compute_nr_groups(sb, partition);
202 		block = first_block + (sizeof(struct spaceBitmapDesc) << 3);
203 		block_group = block >> (sb->s_blocksize_bits + 3);
204 		group_start = block_group ? 0 : sizeof(struct spaceBitmapDesc);
205 
206 		bitmap_nr = load_block_bitmap(sb, bitmap, block_group);
207 		if (bitmap_nr < 0)
208 			goto out;
209 		bh = bitmap->s_block_bitmap[bitmap_nr];
210 
211 		bit = block % (sb->s_blocksize << 3);
212 
213 		while (bit < (sb->s_blocksize << 3) && block_count > 0) {
214 			if (!udf_test_bit(bit, bh->b_data))
215 				goto out;
216 			else if (dquot_prealloc_block(inode, 1))
217 				goto out;
218 			else if (!udf_clear_bit(bit, bh->b_data)) {
219 				udf_debug("bit already cleared for block %d\n", bit);
220 				dquot_free_block(inode, 1);
221 				goto out;
222 			}
223 			block_count--;
224 			alloc_count++;
225 			bit++;
226 			block++;
227 		}
228 		mark_buffer_dirty(bh);
229 	} while (block_count > 0);
230 
231 out:
232 	udf_add_free_space(sb, partition, -alloc_count);
233 	mutex_unlock(&sbi->s_alloc_mutex);
234 	return alloc_count;
235 }
236 
237 static int udf_bitmap_new_block(struct super_block *sb,
238 				struct inode *inode,
239 				struct udf_bitmap *bitmap, uint16_t partition,
240 				uint32_t goal, int *err)
241 {
242 	struct udf_sb_info *sbi = UDF_SB(sb);
243 	int newbit, bit = 0, block, block_group, group_start;
244 	int end_goal, nr_groups, bitmap_nr, i;
245 	struct buffer_head *bh = NULL;
246 	char *ptr;
247 	int newblock = 0;
248 
249 	*err = -ENOSPC;
250 	mutex_lock(&sbi->s_alloc_mutex);
251 
252 repeat:
253 	if (goal >= sbi->s_partmaps[partition].s_partition_len)
254 		goal = 0;
255 
256 	nr_groups = bitmap->s_nr_groups;
257 	block = goal + (sizeof(struct spaceBitmapDesc) << 3);
258 	block_group = block >> (sb->s_blocksize_bits + 3);
259 	group_start = block_group ? 0 : sizeof(struct spaceBitmapDesc);
260 
261 	bitmap_nr = load_block_bitmap(sb, bitmap, block_group);
262 	if (bitmap_nr < 0)
263 		goto error_return;
264 	bh = bitmap->s_block_bitmap[bitmap_nr];
265 	ptr = memscan((char *)bh->b_data + group_start, 0xFF,
266 		      sb->s_blocksize - group_start);
267 
268 	if ((ptr - ((char *)bh->b_data)) < sb->s_blocksize) {
269 		bit = block % (sb->s_blocksize << 3);
270 		if (udf_test_bit(bit, bh->b_data))
271 			goto got_block;
272 
273 		end_goal = (bit + 63) & ~63;
274 		bit = udf_find_next_one_bit(bh->b_data, end_goal, bit);
275 		if (bit < end_goal)
276 			goto got_block;
277 
278 		ptr = memscan((char *)bh->b_data + (bit >> 3), 0xFF,
279 			      sb->s_blocksize - ((bit + 7) >> 3));
280 		newbit = (ptr - ((char *)bh->b_data)) << 3;
281 		if (newbit < sb->s_blocksize << 3) {
282 			bit = newbit;
283 			goto search_back;
284 		}
285 
286 		newbit = udf_find_next_one_bit(bh->b_data,
287 					       sb->s_blocksize << 3, bit);
288 		if (newbit < sb->s_blocksize << 3) {
289 			bit = newbit;
290 			goto got_block;
291 		}
292 	}
293 
294 	for (i = 0; i < (nr_groups * 2); i++) {
295 		block_group++;
296 		if (block_group >= nr_groups)
297 			block_group = 0;
298 		group_start = block_group ? 0 : sizeof(struct spaceBitmapDesc);
299 
300 		bitmap_nr = load_block_bitmap(sb, bitmap, block_group);
301 		if (bitmap_nr < 0)
302 			goto error_return;
303 		bh = bitmap->s_block_bitmap[bitmap_nr];
304 		if (i < nr_groups) {
305 			ptr = memscan((char *)bh->b_data + group_start, 0xFF,
306 				      sb->s_blocksize - group_start);
307 			if ((ptr - ((char *)bh->b_data)) < sb->s_blocksize) {
308 				bit = (ptr - ((char *)bh->b_data)) << 3;
309 				break;
310 			}
311 		} else {
312 			bit = udf_find_next_one_bit((char *)bh->b_data,
313 						    sb->s_blocksize << 3,
314 						    group_start << 3);
315 			if (bit < sb->s_blocksize << 3)
316 				break;
317 		}
318 	}
319 	if (i >= (nr_groups * 2)) {
320 		mutex_unlock(&sbi->s_alloc_mutex);
321 		return newblock;
322 	}
323 	if (bit < sb->s_blocksize << 3)
324 		goto search_back;
325 	else
326 		bit = udf_find_next_one_bit(bh->b_data, sb->s_blocksize << 3,
327 					    group_start << 3);
328 	if (bit >= sb->s_blocksize << 3) {
329 		mutex_unlock(&sbi->s_alloc_mutex);
330 		return 0;
331 	}
332 
333 search_back:
334 	i = 0;
335 	while (i < 7 && bit > (group_start << 3) &&
336 	       udf_test_bit(bit - 1, bh->b_data)) {
337 		++i;
338 		--bit;
339 	}
340 
341 got_block:
342 
343 	/*
344 	 * Check quota for allocation of this block.
345 	 */
346 	if (inode) {
347 		int ret = dquot_alloc_block(inode, 1);
348 
349 		if (ret) {
350 			mutex_unlock(&sbi->s_alloc_mutex);
351 			*err = ret;
352 			return 0;
353 		}
354 	}
355 
356 	newblock = bit + (block_group << (sb->s_blocksize_bits + 3)) -
357 		(sizeof(struct spaceBitmapDesc) << 3);
358 
359 	if (!udf_clear_bit(bit, bh->b_data)) {
360 		udf_debug("bit already cleared for block %d\n", bit);
361 		goto repeat;
362 	}
363 
364 	mark_buffer_dirty(bh);
365 
366 	udf_add_free_space(sb, partition, -1);
367 	mutex_unlock(&sbi->s_alloc_mutex);
368 	*err = 0;
369 	return newblock;
370 
371 error_return:
372 	*err = -EIO;
373 	mutex_unlock(&sbi->s_alloc_mutex);
374 	return 0;
375 }
376 
377 static void udf_table_free_blocks(struct super_block *sb,
378 				  struct inode *inode,
379 				  struct inode *table,
380 				  struct kernel_lb_addr *bloc,
381 				  uint32_t offset,
382 				  uint32_t count)
383 {
384 	struct udf_sb_info *sbi = UDF_SB(sb);
385 	struct udf_part_map *partmap;
386 	uint32_t start, end;
387 	uint32_t elen;
388 	struct kernel_lb_addr eloc;
389 	struct extent_position oepos, epos;
390 	int8_t etype;
391 	int i;
392 	struct udf_inode_info *iinfo;
393 
394 	mutex_lock(&sbi->s_alloc_mutex);
395 	partmap = &sbi->s_partmaps[bloc->partitionReferenceNum];
396 	if (bloc->logicalBlockNum < 0 ||
397 	    (bloc->logicalBlockNum + count) >
398 		partmap->s_partition_len) {
399 		udf_debug("%d < %d || %d + %d > %d\n",
400 			  bloc->logicalBlockNum, 0, bloc->logicalBlockNum, count,
401 			  partmap->s_partition_len);
402 		goto error_return;
403 	}
404 
405 	iinfo = UDF_I(table);
406 	/* We do this up front - There are some error conditions that
407 	   could occure, but.. oh well */
408 	if (inode)
409 		dquot_free_block(inode, count);
410 	udf_add_free_space(sb, sbi->s_partition, count);
411 
412 	start = bloc->logicalBlockNum + offset;
413 	end = bloc->logicalBlockNum + offset + count - 1;
414 
415 	epos.offset = oepos.offset = sizeof(struct unallocSpaceEntry);
416 	elen = 0;
417 	epos.block = oepos.block = iinfo->i_location;
418 	epos.bh = oepos.bh = NULL;
419 
420 	while (count &&
421 	       (etype = udf_next_aext(table, &epos, &eloc, &elen, 1)) != -1) {
422 		if (((eloc.logicalBlockNum +
423 			(elen >> sb->s_blocksize_bits)) == start)) {
424 			if ((0x3FFFFFFF - elen) <
425 					(count << sb->s_blocksize_bits)) {
426 				uint32_t tmp = ((0x3FFFFFFF - elen) >>
427 							sb->s_blocksize_bits);
428 				count -= tmp;
429 				start += tmp;
430 				elen = (etype << 30) |
431 					(0x40000000 - sb->s_blocksize);
432 			} else {
433 				elen = (etype << 30) |
434 					(elen +
435 					(count << sb->s_blocksize_bits));
436 				start += count;
437 				count = 0;
438 			}
439 			udf_write_aext(table, &oepos, &eloc, elen, 1);
440 		} else if (eloc.logicalBlockNum == (end + 1)) {
441 			if ((0x3FFFFFFF - elen) <
442 					(count << sb->s_blocksize_bits)) {
443 				uint32_t tmp = ((0x3FFFFFFF - elen) >>
444 						sb->s_blocksize_bits);
445 				count -= tmp;
446 				end -= tmp;
447 				eloc.logicalBlockNum -= tmp;
448 				elen = (etype << 30) |
449 					(0x40000000 - sb->s_blocksize);
450 			} else {
451 				eloc.logicalBlockNum = start;
452 				elen = (etype << 30) |
453 					(elen +
454 					(count << sb->s_blocksize_bits));
455 				end -= count;
456 				count = 0;
457 			}
458 			udf_write_aext(table, &oepos, &eloc, elen, 1);
459 		}
460 
461 		if (epos.bh != oepos.bh) {
462 			i = -1;
463 			oepos.block = epos.block;
464 			brelse(oepos.bh);
465 			get_bh(epos.bh);
466 			oepos.bh = epos.bh;
467 			oepos.offset = 0;
468 		} else {
469 			oepos.offset = epos.offset;
470 		}
471 	}
472 
473 	if (count) {
474 		/*
475 		 * NOTE: we CANNOT use udf_add_aext here, as it can try to
476 		 * allocate a new block, and since we hold the super block
477 		 * lock already very bad things would happen :)
478 		 *
479 		 * We copy the behavior of udf_add_aext, but instead of
480 		 * trying to allocate a new block close to the existing one,
481 		 * we just steal a block from the extent we are trying to add.
482 		 *
483 		 * It would be nice if the blocks were close together, but it
484 		 * isn't required.
485 		 */
486 
487 		int adsize;
488 		struct short_ad *sad = NULL;
489 		struct long_ad *lad = NULL;
490 		struct allocExtDesc *aed;
491 
492 		eloc.logicalBlockNum = start;
493 		elen = EXT_RECORDED_ALLOCATED |
494 			(count << sb->s_blocksize_bits);
495 
496 		if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
497 			adsize = sizeof(struct short_ad);
498 		else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
499 			adsize = sizeof(struct long_ad);
500 		else {
501 			brelse(oepos.bh);
502 			brelse(epos.bh);
503 			goto error_return;
504 		}
505 
506 		if (epos.offset + (2 * adsize) > sb->s_blocksize) {
507 			unsigned char *sptr, *dptr;
508 			int loffset;
509 
510 			brelse(oepos.bh);
511 			oepos = epos;
512 
513 			/* Steal a block from the extent being free'd */
514 			epos.block.logicalBlockNum = eloc.logicalBlockNum;
515 			eloc.logicalBlockNum++;
516 			elen -= sb->s_blocksize;
517 
518 			epos.bh = udf_tread(sb,
519 					udf_get_lb_pblock(sb, &epos.block, 0));
520 			if (!epos.bh) {
521 				brelse(oepos.bh);
522 				goto error_return;
523 			}
524 			aed = (struct allocExtDesc *)(epos.bh->b_data);
525 			aed->previousAllocExtLocation =
526 				cpu_to_le32(oepos.block.logicalBlockNum);
527 			if (epos.offset + adsize > sb->s_blocksize) {
528 				loffset = epos.offset;
529 				aed->lengthAllocDescs = cpu_to_le32(adsize);
530 				sptr = iinfo->i_ext.i_data + epos.offset
531 								- adsize;
532 				dptr = epos.bh->b_data +
533 					sizeof(struct allocExtDesc);
534 				memcpy(dptr, sptr, adsize);
535 				epos.offset = sizeof(struct allocExtDesc) +
536 						adsize;
537 			} else {
538 				loffset = epos.offset + adsize;
539 				aed->lengthAllocDescs = cpu_to_le32(0);
540 				if (oepos.bh) {
541 					sptr = oepos.bh->b_data + epos.offset;
542 					aed = (struct allocExtDesc *)
543 						oepos.bh->b_data;
544 					le32_add_cpu(&aed->lengthAllocDescs,
545 							adsize);
546 				} else {
547 					sptr = iinfo->i_ext.i_data +
548 								epos.offset;
549 					iinfo->i_lenAlloc += adsize;
550 					mark_inode_dirty(table);
551 				}
552 				epos.offset = sizeof(struct allocExtDesc);
553 			}
554 			if (sbi->s_udfrev >= 0x0200)
555 				udf_new_tag(epos.bh->b_data, TAG_IDENT_AED,
556 					    3, 1, epos.block.logicalBlockNum,
557 					    sizeof(struct tag));
558 			else
559 				udf_new_tag(epos.bh->b_data, TAG_IDENT_AED,
560 					    2, 1, epos.block.logicalBlockNum,
561 					    sizeof(struct tag));
562 
563 			switch (iinfo->i_alloc_type) {
564 			case ICBTAG_FLAG_AD_SHORT:
565 				sad = (struct short_ad *)sptr;
566 				sad->extLength = cpu_to_le32(
567 					EXT_NEXT_EXTENT_ALLOCDECS |
568 					sb->s_blocksize);
569 				sad->extPosition =
570 					cpu_to_le32(epos.block.logicalBlockNum);
571 				break;
572 			case ICBTAG_FLAG_AD_LONG:
573 				lad = (struct long_ad *)sptr;
574 				lad->extLength = cpu_to_le32(
575 					EXT_NEXT_EXTENT_ALLOCDECS |
576 					sb->s_blocksize);
577 				lad->extLocation =
578 					cpu_to_lelb(epos.block);
579 				break;
580 			}
581 			if (oepos.bh) {
582 				udf_update_tag(oepos.bh->b_data, loffset);
583 				mark_buffer_dirty(oepos.bh);
584 			} else {
585 				mark_inode_dirty(table);
586 			}
587 		}
588 
589 		/* It's possible that stealing the block emptied the extent */
590 		if (elen) {
591 			udf_write_aext(table, &epos, &eloc, elen, 1);
592 
593 			if (!epos.bh) {
594 				iinfo->i_lenAlloc += adsize;
595 				mark_inode_dirty(table);
596 			} else {
597 				aed = (struct allocExtDesc *)epos.bh->b_data;
598 				le32_add_cpu(&aed->lengthAllocDescs, adsize);
599 				udf_update_tag(epos.bh->b_data, epos.offset);
600 				mark_buffer_dirty(epos.bh);
601 			}
602 		}
603 	}
604 
605 	brelse(epos.bh);
606 	brelse(oepos.bh);
607 
608 error_return:
609 	mutex_unlock(&sbi->s_alloc_mutex);
610 	return;
611 }
612 
613 static int udf_table_prealloc_blocks(struct super_block *sb,
614 				     struct inode *inode,
615 				     struct inode *table, uint16_t partition,
616 				     uint32_t first_block, uint32_t block_count)
617 {
618 	struct udf_sb_info *sbi = UDF_SB(sb);
619 	int alloc_count = 0;
620 	uint32_t elen, adsize;
621 	struct kernel_lb_addr eloc;
622 	struct extent_position epos;
623 	int8_t etype = -1;
624 	struct udf_inode_info *iinfo;
625 
626 	if (first_block >= sbi->s_partmaps[partition].s_partition_len)
627 		return 0;
628 
629 	iinfo = UDF_I(table);
630 	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
631 		adsize = sizeof(struct short_ad);
632 	else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
633 		adsize = sizeof(struct long_ad);
634 	else
635 		return 0;
636 
637 	mutex_lock(&sbi->s_alloc_mutex);
638 	epos.offset = sizeof(struct unallocSpaceEntry);
639 	epos.block = iinfo->i_location;
640 	epos.bh = NULL;
641 	eloc.logicalBlockNum = 0xFFFFFFFF;
642 
643 	while (first_block != eloc.logicalBlockNum &&
644 	       (etype = udf_next_aext(table, &epos, &eloc, &elen, 1)) != -1) {
645 		udf_debug("eloc=%d, elen=%d, first_block=%d\n",
646 			  eloc.logicalBlockNum, elen, first_block);
647 		; /* empty loop body */
648 	}
649 
650 	if (first_block == eloc.logicalBlockNum) {
651 		epos.offset -= adsize;
652 
653 		alloc_count = (elen >> sb->s_blocksize_bits);
654 		if (inode && dquot_prealloc_block(inode,
655 			alloc_count > block_count ? block_count : alloc_count))
656 			alloc_count = 0;
657 		else if (alloc_count > block_count) {
658 			alloc_count = block_count;
659 			eloc.logicalBlockNum += alloc_count;
660 			elen -= (alloc_count << sb->s_blocksize_bits);
661 			udf_write_aext(table, &epos, &eloc,
662 					(etype << 30) | elen, 1);
663 		} else
664 			udf_delete_aext(table, epos, eloc,
665 					(etype << 30) | elen);
666 	} else {
667 		alloc_count = 0;
668 	}
669 
670 	brelse(epos.bh);
671 
672 	if (alloc_count)
673 		udf_add_free_space(sb, partition, -alloc_count);
674 	mutex_unlock(&sbi->s_alloc_mutex);
675 	return alloc_count;
676 }
677 
678 static int udf_table_new_block(struct super_block *sb,
679 			       struct inode *inode,
680 			       struct inode *table, uint16_t partition,
681 			       uint32_t goal, int *err)
682 {
683 	struct udf_sb_info *sbi = UDF_SB(sb);
684 	uint32_t spread = 0xFFFFFFFF, nspread = 0xFFFFFFFF;
685 	uint32_t newblock = 0, adsize;
686 	uint32_t elen, goal_elen = 0;
687 	struct kernel_lb_addr eloc, uninitialized_var(goal_eloc);
688 	struct extent_position epos, goal_epos;
689 	int8_t etype;
690 	struct udf_inode_info *iinfo = UDF_I(table);
691 
692 	*err = -ENOSPC;
693 
694 	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
695 		adsize = sizeof(struct short_ad);
696 	else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
697 		adsize = sizeof(struct long_ad);
698 	else
699 		return newblock;
700 
701 	mutex_lock(&sbi->s_alloc_mutex);
702 	if (goal >= sbi->s_partmaps[partition].s_partition_len)
703 		goal = 0;
704 
705 	/* We search for the closest matching block to goal. If we find
706 	   a exact hit, we stop. Otherwise we keep going till we run out
707 	   of extents. We store the buffer_head, bloc, and extoffset
708 	   of the current closest match and use that when we are done.
709 	 */
710 	epos.offset = sizeof(struct unallocSpaceEntry);
711 	epos.block = iinfo->i_location;
712 	epos.bh = goal_epos.bh = NULL;
713 
714 	while (spread &&
715 	       (etype = udf_next_aext(table, &epos, &eloc, &elen, 1)) != -1) {
716 		if (goal >= eloc.logicalBlockNum) {
717 			if (goal < eloc.logicalBlockNum +
718 					(elen >> sb->s_blocksize_bits))
719 				nspread = 0;
720 			else
721 				nspread = goal - eloc.logicalBlockNum -
722 					(elen >> sb->s_blocksize_bits);
723 		} else {
724 			nspread = eloc.logicalBlockNum - goal;
725 		}
726 
727 		if (nspread < spread) {
728 			spread = nspread;
729 			if (goal_epos.bh != epos.bh) {
730 				brelse(goal_epos.bh);
731 				goal_epos.bh = epos.bh;
732 				get_bh(goal_epos.bh);
733 			}
734 			goal_epos.block = epos.block;
735 			goal_epos.offset = epos.offset - adsize;
736 			goal_eloc = eloc;
737 			goal_elen = (etype << 30) | elen;
738 		}
739 	}
740 
741 	brelse(epos.bh);
742 
743 	if (spread == 0xFFFFFFFF) {
744 		brelse(goal_epos.bh);
745 		mutex_unlock(&sbi->s_alloc_mutex);
746 		return 0;
747 	}
748 
749 	/* Only allocate blocks from the beginning of the extent.
750 	   That way, we only delete (empty) extents, never have to insert an
751 	   extent because of splitting */
752 	/* This works, but very poorly.... */
753 
754 	newblock = goal_eloc.logicalBlockNum;
755 	goal_eloc.logicalBlockNum++;
756 	goal_elen -= sb->s_blocksize;
757 	if (inode) {
758 		*err = dquot_alloc_block(inode, 1);
759 		if (*err) {
760 			brelse(goal_epos.bh);
761 			mutex_unlock(&sbi->s_alloc_mutex);
762 			return 0;
763 		}
764 	}
765 
766 	if (goal_elen)
767 		udf_write_aext(table, &goal_epos, &goal_eloc, goal_elen, 1);
768 	else
769 		udf_delete_aext(table, goal_epos, goal_eloc, goal_elen);
770 	brelse(goal_epos.bh);
771 
772 	udf_add_free_space(sb, partition, -1);
773 
774 	mutex_unlock(&sbi->s_alloc_mutex);
775 	*err = 0;
776 	return newblock;
777 }
778 
779 void udf_free_blocks(struct super_block *sb, struct inode *inode,
780 		     struct kernel_lb_addr *bloc, uint32_t offset,
781 		     uint32_t count)
782 {
783 	uint16_t partition = bloc->partitionReferenceNum;
784 	struct udf_part_map *map = &UDF_SB(sb)->s_partmaps[partition];
785 
786 	if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_BITMAP) {
787 		udf_bitmap_free_blocks(sb, inode, map->s_uspace.s_bitmap,
788 				       bloc, offset, count);
789 	} else if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_TABLE) {
790 		udf_table_free_blocks(sb, inode, map->s_uspace.s_table,
791 				      bloc, offset, count);
792 	} else if (map->s_partition_flags & UDF_PART_FLAG_FREED_BITMAP) {
793 		udf_bitmap_free_blocks(sb, inode, map->s_fspace.s_bitmap,
794 				       bloc, offset, count);
795 	} else if (map->s_partition_flags & UDF_PART_FLAG_FREED_TABLE) {
796 		udf_table_free_blocks(sb, inode, map->s_fspace.s_table,
797 				      bloc, offset, count);
798 	}
799 }
800 
801 inline int udf_prealloc_blocks(struct super_block *sb,
802 			       struct inode *inode,
803 			       uint16_t partition, uint32_t first_block,
804 			       uint32_t block_count)
805 {
806 	struct udf_part_map *map = &UDF_SB(sb)->s_partmaps[partition];
807 
808 	if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_BITMAP)
809 		return udf_bitmap_prealloc_blocks(sb, inode,
810 						  map->s_uspace.s_bitmap,
811 						  partition, first_block,
812 						  block_count);
813 	else if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_TABLE)
814 		return udf_table_prealloc_blocks(sb, inode,
815 						 map->s_uspace.s_table,
816 						 partition, first_block,
817 						 block_count);
818 	else if (map->s_partition_flags & UDF_PART_FLAG_FREED_BITMAP)
819 		return udf_bitmap_prealloc_blocks(sb, inode,
820 						  map->s_fspace.s_bitmap,
821 						  partition, first_block,
822 						  block_count);
823 	else if (map->s_partition_flags & UDF_PART_FLAG_FREED_TABLE)
824 		return udf_table_prealloc_blocks(sb, inode,
825 						 map->s_fspace.s_table,
826 						 partition, first_block,
827 						 block_count);
828 	else
829 		return 0;
830 }
831 
832 inline int udf_new_block(struct super_block *sb,
833 			 struct inode *inode,
834 			 uint16_t partition, uint32_t goal, int *err)
835 {
836 	struct udf_part_map *map = &UDF_SB(sb)->s_partmaps[partition];
837 
838 	if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_BITMAP)
839 		return udf_bitmap_new_block(sb, inode,
840 					   map->s_uspace.s_bitmap,
841 					   partition, goal, err);
842 	else if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_TABLE)
843 		return udf_table_new_block(sb, inode,
844 					   map->s_uspace.s_table,
845 					   partition, goal, err);
846 	else if (map->s_partition_flags & UDF_PART_FLAG_FREED_BITMAP)
847 		return udf_bitmap_new_block(sb, inode,
848 					    map->s_fspace.s_bitmap,
849 					    partition, goal, err);
850 	else if (map->s_partition_flags & UDF_PART_FLAG_FREED_TABLE)
851 		return udf_table_new_block(sb, inode,
852 					   map->s_fspace.s_table,
853 					   partition, goal, err);
854 	else {
855 		*err = -EIO;
856 		return 0;
857 	}
858 }
859