balloc.c 21.7 KB
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825
/*
 * balloc.c
 *
 * PURPOSE
 *	Block allocation handling routines for the OSTA-UDF(tm) filesystem.
 *
 * COPYRIGHT
 *	This file is distributed under the terms of the GNU General Public
 *	License (GPL). Copies of the GPL can be obtained from:
 *		ftp://prep.ai.mit.edu/pub/gnu/GPL
 *	Each contributing author retains all rights to their own work.
 *
 *  (C) 1999-2001 Ben Fennema
 *  (C) 1999 Stelias Computing Inc
 *
 * HISTORY
 *
 *  02/24/99 blf  Created.
 *
 */

#include "udfdecl.h"

#include <linux/buffer_head.h>
#include <linux/bitops.h>

#include "udf_i.h"
#include "udf_sb.h"

#define udf_clear_bit	__test_and_clear_bit_le
#define udf_set_bit	__test_and_set_bit_le
#define udf_test_bit	test_bit_le
#define udf_find_next_one_bit	find_next_bit_le

static int read_block_bitmap(struct super_block *sb,
			     struct udf_bitmap *bitmap, unsigned int block,
			     unsigned long bitmap_nr)
{
	struct buffer_head *bh = NULL;
	int retval = 0;
	struct kernel_lb_addr loc;

	loc.logicalBlockNum = bitmap->s_extPosition;
	loc.partitionReferenceNum = UDF_SB(sb)->s_partition;

	bh = udf_tread(sb, udf_get_lb_pblock(sb, &loc, block));
	if (!bh)
		retval = -EIO;

	bitmap->s_block_bitmap[bitmap_nr] = bh;
	return retval;
}

static int __load_block_bitmap(struct super_block *sb,
			       struct udf_bitmap *bitmap,
			       unsigned int block_group)
{
	int retval = 0;
	int nr_groups = bitmap->s_nr_groups;

	if (block_group >= nr_groups) {
		udf_debug("block_group (%d) > nr_groups (%d)\n",
			  block_group, nr_groups);
	}

	if (bitmap->s_block_bitmap[block_group]) {
		return block_group;
	} else {
		retval = read_block_bitmap(sb, bitmap, block_group,
					   block_group);
		if (retval < 0)
			return retval;
		return block_group;
	}
}

static inline int load_block_bitmap(struct super_block *sb,
				    struct udf_bitmap *bitmap,
				    unsigned int block_group)
{
	int slot;

	slot = __load_block_bitmap(sb, bitmap, block_group);

	if (slot < 0)
		return slot;

	if (!bitmap->s_block_bitmap[slot])
		return -EIO;

	return slot;
}

static void udf_add_free_space(struct super_block *sb, u16 partition, u32 cnt)
{
	struct udf_sb_info *sbi = UDF_SB(sb);
	struct logicalVolIntegrityDesc *lvid;

	if (!sbi->s_lvid_bh)
		return;

	lvid = (struct logicalVolIntegrityDesc *)sbi->s_lvid_bh->b_data;
	le32_add_cpu(&lvid->freeSpaceTable[partition], cnt);
	udf_updated_lvid(sb);
}

static void udf_bitmap_free_blocks(struct super_block *sb,
				   struct udf_bitmap *bitmap,
				   struct kernel_lb_addr *bloc,
				   uint32_t offset,
				   uint32_t count)
{
	struct udf_sb_info *sbi = UDF_SB(sb);
	struct buffer_head *bh = NULL;
	struct udf_part_map *partmap;
	unsigned long block;
	unsigned long block_group;
	unsigned long bit;
	unsigned long i;
	int bitmap_nr;
	unsigned long overflow;

	mutex_lock(&sbi->s_alloc_mutex);
	partmap = &sbi->s_partmaps[bloc->partitionReferenceNum];
	if (bloc->logicalBlockNum + count < count ||
	    (bloc->logicalBlockNum + count) > partmap->s_partition_len) {
		udf_debug("%d < %d || %d + %d > %d\n",
			  bloc->logicalBlockNum, 0,
			  bloc->logicalBlockNum, count,
			  partmap->s_partition_len);
		goto error_return;
	}

	block = bloc->logicalBlockNum + offset +
		(sizeof(struct spaceBitmapDesc) << 3);

	do {
		overflow = 0;
		block_group = block >> (sb->s_blocksize_bits + 3);
		bit = block % (sb->s_blocksize << 3);

		/*
		* Check to see if we are freeing blocks across a group boundary.
		*/
		if (bit + count > (sb->s_blocksize << 3)) {
			overflow = bit + count - (sb->s_blocksize << 3);
			count -= overflow;
		}
		bitmap_nr = load_block_bitmap(sb, bitmap, block_group);
		if (bitmap_nr < 0)
			goto error_return;

		bh = bitmap->s_block_bitmap[bitmap_nr];
		for (i = 0; i < count; i++) {
			if (udf_set_bit(bit + i, bh->b_data)) {
				udf_debug("bit %ld already set\n", bit + i);
				udf_debug("byte=%2x\n",
					  ((char *)bh->b_data)[(bit + i) >> 3]);
			}
		}
		udf_add_free_space(sb, sbi->s_partition, count);
		mark_buffer_dirty(bh);
		if (overflow) {
			block += count;
			count = overflow;
		}
	} while (overflow);

error_return:
	mutex_unlock(&sbi->s_alloc_mutex);
}

static int udf_bitmap_prealloc_blocks(struct super_block *sb,
				      struct udf_bitmap *bitmap,
				      uint16_t partition, uint32_t first_block,
				      uint32_t block_count)
{
	struct udf_sb_info *sbi = UDF_SB(sb);
	int alloc_count = 0;
	int bit, block, block_group, group_start;
	int nr_groups, bitmap_nr;
	struct buffer_head *bh;
	__u32 part_len;

	mutex_lock(&sbi->s_alloc_mutex);
	part_len = sbi->s_partmaps[partition].s_partition_len;
	if (first_block >= part_len)
		goto out;

	if (first_block + block_count > part_len)
		block_count = part_len - first_block;

	do {
		nr_groups = udf_compute_nr_groups(sb, partition);
		block = first_block + (sizeof(struct spaceBitmapDesc) << 3);
		block_group = block >> (sb->s_blocksize_bits + 3);
		group_start = block_group ? 0 : sizeof(struct spaceBitmapDesc);

		bitmap_nr = load_block_bitmap(sb, bitmap, block_group);
		if (bitmap_nr < 0)
			goto out;
		bh = bitmap->s_block_bitmap[bitmap_nr];

		bit = block % (sb->s_blocksize << 3);

		while (bit < (sb->s_blocksize << 3) && block_count > 0) {
			if (!udf_clear_bit(bit, bh->b_data))
				goto out;
			block_count--;
			alloc_count++;
			bit++;
			block++;
		}
		mark_buffer_dirty(bh);
	} while (block_count > 0);

out:
	udf_add_free_space(sb, partition, -alloc_count);
	mutex_unlock(&sbi->s_alloc_mutex);
	return alloc_count;
}

static int udf_bitmap_new_block(struct super_block *sb,
				struct udf_bitmap *bitmap, uint16_t partition,
				uint32_t goal, int *err)
{
	struct udf_sb_info *sbi = UDF_SB(sb);
	int newbit, bit = 0, block, block_group, group_start;
	int end_goal, nr_groups, bitmap_nr, i;
	struct buffer_head *bh = NULL;
	char *ptr;
	int newblock = 0;

	*err = -ENOSPC;
	mutex_lock(&sbi->s_alloc_mutex);

repeat:
	if (goal >= sbi->s_partmaps[partition].s_partition_len)
		goal = 0;

	nr_groups = bitmap->s_nr_groups;
	block = goal + (sizeof(struct spaceBitmapDesc) << 3);
	block_group = block >> (sb->s_blocksize_bits + 3);
	group_start = block_group ? 0 : sizeof(struct spaceBitmapDesc);

	bitmap_nr = load_block_bitmap(sb, bitmap, block_group);
	if (bitmap_nr < 0)
		goto error_return;
	bh = bitmap->s_block_bitmap[bitmap_nr];
	ptr = memscan((char *)bh->b_data + group_start, 0xFF,
		      sb->s_blocksize - group_start);

	if ((ptr - ((char *)bh->b_data)) < sb->s_blocksize) {
		bit = block % (sb->s_blocksize << 3);
		if (udf_test_bit(bit, bh->b_data))
			goto got_block;

		end_goal = (bit + 63) & ~63;
		bit = udf_find_next_one_bit(bh->b_data, end_goal, bit);
		if (bit < end_goal)
			goto got_block;

		ptr = memscan((char *)bh->b_data + (bit >> 3), 0xFF,
			      sb->s_blocksize - ((bit + 7) >> 3));
		newbit = (ptr - ((char *)bh->b_data)) << 3;
		if (newbit < sb->s_blocksize << 3) {
			bit = newbit;
			goto search_back;
		}

		newbit = udf_find_next_one_bit(bh->b_data,
					       sb->s_blocksize << 3, bit);
		if (newbit < sb->s_blocksize << 3) {
			bit = newbit;
			goto got_block;
		}
	}

	for (i = 0; i < (nr_groups * 2); i++) {
		block_group++;
		if (block_group >= nr_groups)
			block_group = 0;
		group_start = block_group ? 0 : sizeof(struct spaceBitmapDesc);

		bitmap_nr = load_block_bitmap(sb, bitmap, block_group);
		if (bitmap_nr < 0)
			goto error_return;
		bh = bitmap->s_block_bitmap[bitmap_nr];
		if (i < nr_groups) {
			ptr = memscan((char *)bh->b_data + group_start, 0xFF,
				      sb->s_blocksize - group_start);
			if ((ptr - ((char *)bh->b_data)) < sb->s_blocksize) {
				bit = (ptr - ((char *)bh->b_data)) << 3;
				break;
			}
		} else {
			bit = udf_find_next_one_bit(bh->b_data,
						    sb->s_blocksize << 3,
						    group_start << 3);
			if (bit < sb->s_blocksize << 3)
				break;
		}
	}
	if (i >= (nr_groups * 2)) {
		mutex_unlock(&sbi->s_alloc_mutex);
		return newblock;
	}
	if (bit < sb->s_blocksize << 3)
		goto search_back;
	else
		bit = udf_find_next_one_bit(bh->b_data, sb->s_blocksize << 3,
					    group_start << 3);
	if (bit >= sb->s_blocksize << 3) {
		mutex_unlock(&sbi->s_alloc_mutex);
		return 0;
	}

search_back:
	i = 0;
	while (i < 7 && bit > (group_start << 3) &&
	       udf_test_bit(bit - 1, bh->b_data)) {
		++i;
		--bit;
	}

got_block:
	newblock = bit + (block_group << (sb->s_blocksize_bits + 3)) -
		(sizeof(struct spaceBitmapDesc) << 3);

	if (!udf_clear_bit(bit, bh->b_data)) {
		udf_debug("bit already cleared for block %d\n", bit);
		goto repeat;
	}

	mark_buffer_dirty(bh);

	udf_add_free_space(sb, partition, -1);
	mutex_unlock(&sbi->s_alloc_mutex);
	*err = 0;
	return newblock;

error_return:
	*err = -EIO;
	mutex_unlock(&sbi->s_alloc_mutex);
	return 0;
}

static void udf_table_free_blocks(struct super_block *sb,
				  struct inode *table,
				  struct kernel_lb_addr *bloc,
				  uint32_t offset,
				  uint32_t count)
{
	struct udf_sb_info *sbi = UDF_SB(sb);
	struct udf_part_map *partmap;
	uint32_t start, end;
	uint32_t elen;
	struct kernel_lb_addr eloc;
	struct extent_position oepos, epos;
	int8_t etype;
	int i;
	struct udf_inode_info *iinfo;

	mutex_lock(&sbi->s_alloc_mutex);
	partmap = &sbi->s_partmaps[bloc->partitionReferenceNum];
	if (bloc->logicalBlockNum + count < count ||
	    (bloc->logicalBlockNum + count) > partmap->s_partition_len) {
		udf_debug("%d < %d || %d + %d > %d\n",
			  bloc->logicalBlockNum, 0,
			  bloc->logicalBlockNum, count,
			  partmap->s_partition_len);
		goto error_return;
	}

	iinfo = UDF_I(table);
	udf_add_free_space(sb, sbi->s_partition, count);

	start = bloc->logicalBlockNum + offset;
	end = bloc->logicalBlockNum + offset + count - 1;

	epos.offset = oepos.offset = sizeof(struct unallocSpaceEntry);
	elen = 0;
	epos.block = oepos.block = iinfo->i_location;
	epos.bh = oepos.bh = NULL;

	while (count &&
	       (etype = udf_next_aext(table, &epos, &eloc, &elen, 1)) != -1) {
		if (((eloc.logicalBlockNum +
			(elen >> sb->s_blocksize_bits)) == start)) {
			if ((0x3FFFFFFF - elen) <
					(count << sb->s_blocksize_bits)) {
				uint32_t tmp = ((0x3FFFFFFF - elen) >>
							sb->s_blocksize_bits);
				count -= tmp;
				start += tmp;
				elen = (etype << 30) |
					(0x40000000 - sb->s_blocksize);
			} else {
				elen = (etype << 30) |
					(elen +
					(count << sb->s_blocksize_bits));
				start += count;
				count = 0;
			}
			udf_write_aext(table, &oepos, &eloc, elen, 1);
		} else if (eloc.logicalBlockNum == (end + 1)) {
			if ((0x3FFFFFFF - elen) <
					(count << sb->s_blocksize_bits)) {
				uint32_t tmp = ((0x3FFFFFFF - elen) >>
						sb->s_blocksize_bits);
				count -= tmp;
				end -= tmp;
				eloc.logicalBlockNum -= tmp;
				elen = (etype << 30) |
					(0x40000000 - sb->s_blocksize);
			} else {
				eloc.logicalBlockNum = start;
				elen = (etype << 30) |
					(elen +
					(count << sb->s_blocksize_bits));
				end -= count;
				count = 0;
			}
			udf_write_aext(table, &oepos, &eloc, elen, 1);
		}

		if (epos.bh != oepos.bh) {
			i = -1;
			oepos.block = epos.block;
			brelse(oepos.bh);
			get_bh(epos.bh);
			oepos.bh = epos.bh;
			oepos.offset = 0;
		} else {
			oepos.offset = epos.offset;
		}
	}

	if (count) {
		/*
		 * NOTE: we CANNOT use udf_add_aext here, as it can try to
		 * allocate a new block, and since we hold the super block
		 * lock already very bad things would happen :)
		 *
		 * We copy the behavior of udf_add_aext, but instead of
		 * trying to allocate a new block close to the existing one,
		 * we just steal a block from the extent we are trying to add.
		 *
		 * It would be nice if the blocks were close together, but it
		 * isn't required.
		 */

		int adsize;
		struct short_ad *sad = NULL;
		struct long_ad *lad = NULL;
		struct allocExtDesc *aed;

		eloc.logicalBlockNum = start;
		elen = EXT_RECORDED_ALLOCATED |
			(count << sb->s_blocksize_bits);

		if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
			adsize = sizeof(struct short_ad);
		else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
			adsize = sizeof(struct long_ad);
		else {
			brelse(oepos.bh);
			brelse(epos.bh);
			goto error_return;
		}

		if (epos.offset + (2 * adsize) > sb->s_blocksize) {
			unsigned char *sptr, *dptr;
			int loffset;

			brelse(oepos.bh);
			oepos = epos;

			/* Steal a block from the extent being free'd */
			epos.block.logicalBlockNum = eloc.logicalBlockNum;
			eloc.logicalBlockNum++;
			elen -= sb->s_blocksize;

			epos.bh = udf_tread(sb,
					udf_get_lb_pblock(sb, &epos.block, 0));
			if (!epos.bh) {
				brelse(oepos.bh);
				goto error_return;
			}
			aed = (struct allocExtDesc *)(epos.bh->b_data);
			aed->previousAllocExtLocation =
				cpu_to_le32(oepos.block.logicalBlockNum);
			if (epos.offset + adsize > sb->s_blocksize) {
				loffset = epos.offset;
				aed->lengthAllocDescs = cpu_to_le32(adsize);
				sptr = iinfo->i_ext.i_data + epos.offset
								- adsize;
				dptr = epos.bh->b_data +
					sizeof(struct allocExtDesc);
				memcpy(dptr, sptr, adsize);
				epos.offset = sizeof(struct allocExtDesc) +
						adsize;
			} else {
				loffset = epos.offset + adsize;
				aed->lengthAllocDescs = cpu_to_le32(0);
				if (oepos.bh) {
					sptr = oepos.bh->b_data + epos.offset;
					aed = (struct allocExtDesc *)
						oepos.bh->b_data;
					le32_add_cpu(&aed->lengthAllocDescs,
							adsize);
				} else {
					sptr = iinfo->i_ext.i_data +
								epos.offset;
					iinfo->i_lenAlloc += adsize;
					mark_inode_dirty(table);
				}
				epos.offset = sizeof(struct allocExtDesc);
			}
			if (sbi->s_udfrev >= 0x0200)
				udf_new_tag(epos.bh->b_data, TAG_IDENT_AED,
					    3, 1, epos.block.logicalBlockNum,
					    sizeof(struct tag));
			else
				udf_new_tag(epos.bh->b_data, TAG_IDENT_AED,
					    2, 1, epos.block.logicalBlockNum,
					    sizeof(struct tag));

			switch (iinfo->i_alloc_type) {
			case ICBTAG_FLAG_AD_SHORT:
				sad = (struct short_ad *)sptr;
				sad->extLength = cpu_to_le32(
					EXT_NEXT_EXTENT_ALLOCDECS |
					sb->s_blocksize);
				sad->extPosition =
					cpu_to_le32(epos.block.logicalBlockNum);
				break;
			case ICBTAG_FLAG_AD_LONG:
				lad = (struct long_ad *)sptr;
				lad->extLength = cpu_to_le32(
					EXT_NEXT_EXTENT_ALLOCDECS |
					sb->s_blocksize);
				lad->extLocation =
					cpu_to_lelb(epos.block);
				break;
			}
			if (oepos.bh) {
				udf_update_tag(oepos.bh->b_data, loffset);
				mark_buffer_dirty(oepos.bh);
			} else {
				mark_inode_dirty(table);
			}
		}

		/* It's possible that stealing the block emptied the extent */
		if (elen) {
			udf_write_aext(table, &epos, &eloc, elen, 1);

			if (!epos.bh) {
				iinfo->i_lenAlloc += adsize;
				mark_inode_dirty(table);
			} else {
				aed = (struct allocExtDesc *)epos.bh->b_data;
				le32_add_cpu(&aed->lengthAllocDescs, adsize);
				udf_update_tag(epos.bh->b_data, epos.offset);
				mark_buffer_dirty(epos.bh);
			}
		}
	}

	brelse(epos.bh);
	brelse(oepos.bh);

error_return:
	mutex_unlock(&sbi->s_alloc_mutex);
	return;
}

static int udf_table_prealloc_blocks(struct super_block *sb,
				     struct inode *table, uint16_t partition,
				     uint32_t first_block, uint32_t block_count)
{
	struct udf_sb_info *sbi = UDF_SB(sb);
	int alloc_count = 0;
	uint32_t elen, adsize;
	struct kernel_lb_addr eloc;
	struct extent_position epos;
	int8_t etype = -1;
	struct udf_inode_info *iinfo;

	if (first_block >= sbi->s_partmaps[partition].s_partition_len)
		return 0;

	iinfo = UDF_I(table);
	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
		adsize = sizeof(struct short_ad);
	else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
		adsize = sizeof(struct long_ad);
	else
		return 0;

	mutex_lock(&sbi->s_alloc_mutex);
	epos.offset = sizeof(struct unallocSpaceEntry);
	epos.block = iinfo->i_location;
	epos.bh = NULL;
	eloc.logicalBlockNum = 0xFFFFFFFF;

	while (first_block != eloc.logicalBlockNum &&
	       (etype = udf_next_aext(table, &epos, &eloc, &elen, 1)) != -1) {
		udf_debug("eloc=%d, elen=%d, first_block=%d\n",
			  eloc.logicalBlockNum, elen, first_block);
		; /* empty loop body */
	}

	if (first_block == eloc.logicalBlockNum) {
		epos.offset -= adsize;

		alloc_count = (elen >> sb->s_blocksize_bits);
		if (alloc_count > block_count) {
			alloc_count = block_count;
			eloc.logicalBlockNum += alloc_count;
			elen -= (alloc_count << sb->s_blocksize_bits);
			udf_write_aext(table, &epos, &eloc,
					(etype << 30) | elen, 1);
		} else
			udf_delete_aext(table, epos, eloc,
					(etype << 30) | elen);
	} else {
		alloc_count = 0;
	}

	brelse(epos.bh);

	if (alloc_count)
		udf_add_free_space(sb, partition, -alloc_count);
	mutex_unlock(&sbi->s_alloc_mutex);
	return alloc_count;
}

static int udf_table_new_block(struct super_block *sb,
			       struct inode *table, uint16_t partition,
			       uint32_t goal, int *err)
{
	struct udf_sb_info *sbi = UDF_SB(sb);
	uint32_t spread = 0xFFFFFFFF, nspread = 0xFFFFFFFF;
	uint32_t newblock = 0, adsize;
	uint32_t elen, goal_elen = 0;
	struct kernel_lb_addr eloc, uninitialized_var(goal_eloc);
	struct extent_position epos, goal_epos;
	int8_t etype;
	struct udf_inode_info *iinfo = UDF_I(table);

	*err = -ENOSPC;

	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
		adsize = sizeof(struct short_ad);
	else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
		adsize = sizeof(struct long_ad);
	else
		return newblock;

	mutex_lock(&sbi->s_alloc_mutex);
	if (goal >= sbi->s_partmaps[partition].s_partition_len)
		goal = 0;

	/* We search for the closest matching block to goal. If we find
	   a exact hit, we stop. Otherwise we keep going till we run out
	   of extents. We store the buffer_head, bloc, and extoffset
	   of the current closest match and use that when we are done.
	 */
	epos.offset = sizeof(struct unallocSpaceEntry);
	epos.block = iinfo->i_location;
	epos.bh = goal_epos.bh = NULL;

	while (spread &&
	       (etype = udf_next_aext(table, &epos, &eloc, &elen, 1)) != -1) {
		if (goal >= eloc.logicalBlockNum) {
			if (goal < eloc.logicalBlockNum +
					(elen >> sb->s_blocksize_bits))
				nspread = 0;
			else
				nspread = goal - eloc.logicalBlockNum -
					(elen >> sb->s_blocksize_bits);
		} else {
			nspread = eloc.logicalBlockNum - goal;
		}

		if (nspread < spread) {
			spread = nspread;
			if (goal_epos.bh != epos.bh) {
				brelse(goal_epos.bh);
				goal_epos.bh = epos.bh;
				get_bh(goal_epos.bh);
			}
			goal_epos.block = epos.block;
			goal_epos.offset = epos.offset - adsize;
			goal_eloc = eloc;
			goal_elen = (etype << 30) | elen;
		}
	}

	brelse(epos.bh);

	if (spread == 0xFFFFFFFF) {
		brelse(goal_epos.bh);
		mutex_unlock(&sbi->s_alloc_mutex);
		return 0;
	}

	/* Only allocate blocks from the beginning of the extent.
	   That way, we only delete (empty) extents, never have to insert an
	   extent because of splitting */
	/* This works, but very poorly.... */

	newblock = goal_eloc.logicalBlockNum;
	goal_eloc.logicalBlockNum++;
	goal_elen -= sb->s_blocksize;

	if (goal_elen)
		udf_write_aext(table, &goal_epos, &goal_eloc, goal_elen, 1);
	else
		udf_delete_aext(table, goal_epos, goal_eloc, goal_elen);
	brelse(goal_epos.bh);

	udf_add_free_space(sb, partition, -1);

	mutex_unlock(&sbi->s_alloc_mutex);
	*err = 0;
	return newblock;
}

void udf_free_blocks(struct super_block *sb, struct inode *inode,
		     struct kernel_lb_addr *bloc, uint32_t offset,
		     uint32_t count)
{
	uint16_t partition = bloc->partitionReferenceNum;
	struct udf_part_map *map = &UDF_SB(sb)->s_partmaps[partition];

	if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_BITMAP) {
		udf_bitmap_free_blocks(sb, map->s_uspace.s_bitmap,
				       bloc, offset, count);
	} else if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_TABLE) {
		udf_table_free_blocks(sb, map->s_uspace.s_table,
				      bloc, offset, count);
	} else if (map->s_partition_flags & UDF_PART_FLAG_FREED_BITMAP) {
		udf_bitmap_free_blocks(sb, map->s_fspace.s_bitmap,
				       bloc, offset, count);
	} else if (map->s_partition_flags & UDF_PART_FLAG_FREED_TABLE) {
		udf_table_free_blocks(sb, map->s_fspace.s_table,
				      bloc, offset, count);
	}

	if (inode) {
		inode_sub_bytes(inode,
				((sector_t)count) << sb->s_blocksize_bits);
	}
}

inline int udf_prealloc_blocks(struct super_block *sb,
			       struct inode *inode,
			       uint16_t partition, uint32_t first_block,
			       uint32_t block_count)
{
	struct udf_part_map *map = &UDF_SB(sb)->s_partmaps[partition];
	sector_t allocated;

	if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_BITMAP)
		allocated = udf_bitmap_prealloc_blocks(sb,
						       map->s_uspace.s_bitmap,
						       partition, first_block,
						       block_count);
	else if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_TABLE)
		allocated = udf_table_prealloc_blocks(sb,
						      map->s_uspace.s_table,
						      partition, first_block,
						      block_count);
	else if (map->s_partition_flags & UDF_PART_FLAG_FREED_BITMAP)
		allocated = udf_bitmap_prealloc_blocks(sb,
						       map->s_fspace.s_bitmap,
						       partition, first_block,
						       block_count);
	else if (map->s_partition_flags & UDF_PART_FLAG_FREED_TABLE)
		allocated = udf_table_prealloc_blocks(sb,
						      map->s_fspace.s_table,
						      partition, first_block,
						      block_count);
	else
		return 0;

	if (inode && allocated > 0)
		inode_add_bytes(inode, allocated << sb->s_blocksize_bits);
	return allocated;
}

inline int udf_new_block(struct super_block *sb,
			 struct inode *inode,
			 uint16_t partition, uint32_t goal, int *err)
{
	struct udf_part_map *map = &UDF_SB(sb)->s_partmaps[partition];
	int block;

	if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_BITMAP)
		block = udf_bitmap_new_block(sb,
					     map->s_uspace.s_bitmap,
					     partition, goal, err);
	else if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_TABLE)
		block = udf_table_new_block(sb,
					    map->s_uspace.s_table,
					    partition, goal, err);
	else if (map->s_partition_flags & UDF_PART_FLAG_FREED_BITMAP)
		block = udf_bitmap_new_block(sb,
					     map->s_fspace.s_bitmap,
					     partition, goal, err);
	else if (map->s_partition_flags & UDF_PART_FLAG_FREED_TABLE)
		block = udf_table_new_block(sb,
					    map->s_fspace.s_table,
					    partition, goal, err);
	else {
		*err = -EIO;
		return 0;
	}
	if (inode && block)
		inode_add_bytes(inode, sb->s_blocksize);
	return block;
}