fs/udf/balloc.c

   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(nr, addr) ext2_clear_bit(nr, addr)
  31 #define udf_set_bit(nr, addr) ext2_set_bit(nr, addr)
  32 #define udf_test_bit(nr, addr) ext2_test_bit(nr, addr)
  33 #define udf_find_next_one_bit(addr, size, offset) \
  34                 ext2_find_next_bit(addr, size, offset)
  35
  36 static int read_block_bitmap(struct super_block *sb,
  37                              struct udf_bitmap *bitmap, unsigned int block,
  38                              unsigned long bitmap_nr)
  39 {
  40         struct buffer_head *bh = NULL;
  41         int retval = 0;
  42         struct kernel_lb_addr loc;
  43
  44         loc.logicalBlockNum = bitmap->s_extPosition;
  45         loc.partitionReferenceNum = UDF_SB(sb)->s_partition;
  46
  47         bh = udf_tread(sb, udf_get_lb_pblock(sb, &loc, block));
  48         if (!bh)
  49                 retval = -EIO;
  50
  51         bitmap->s_block_bitmap[bitmap_nr] = bh;
  52         return retval;
  53 }
  54
  55 static int __load_block_bitmap(struct super_block *sb,
  56                                struct udf_bitmap *bitmap,
  57                                unsigned int block_group)
  58 {
  59         int retval = 0;
  60         int nr_groups = bitmap->s_nr_groups;
  61
  62         if (block_group >= nr_groups) {
  63                 udf_debug("block_group (%d) > nr_groups (%d)\n", block_group,
  64                           nr_groups);
  65         }
  66
  67         if (bitmap->s_block_bitmap[block_group]) {
  68                 return block_group;
  69         } else {
  70                 retval = read_block_bitmap(sb, bitmap, block_group,
  71                                            block_group);
  72                 if (retval < 0)
  73                         return retval;
  74                 return block_group;
  75         }
  76 }
  77
  78 static inline int load_block_bitmap(struct super_block *sb,
  79                                     struct udf_bitmap *bitmap,
  80                                     unsigned int block_group)
  81 {
  82         int slot;
  83
  84         slot = __load_block_bitmap(sb, bitmap, block_group);
  85
  86         if (slot < 0)
  87                 return slot;
  88
  89         if (!bitmap->s_block_bitmap[slot])
  90                 return -EIO;
  91
  92         return slot;
  93 }
  94
  95 static void udf_add_free_space(struct super_block *sb, u16 partition, u32 cnt)
  96 {
  97         struct udf_sb_info *sbi = UDF_SB(sb);
  98         struct logicalVolIntegrityDesc *lvid;
  99
 100         if (!sbi->s_lvid_bh)
 101                 return;
 102
 103         lvid = (struct logicalVolIntegrityDesc *)sbi->s_lvid_bh->b_data;
 104         le32_add_cpu(&lvid->freeSpaceTable[partition], cnt);
 105         udf_updated_lvid(sb);
 106 }
 107
 108 static void udf_bitmap_free_blocks(struct super_block *sb,
 109                                    struct inode *inode,
 110                                    struct udf_bitmap *bitmap,
 111                                    struct kernel_lb_addr *bloc,
 112                                    uint32_t offset,
 113                                    uint32_t count)
 114 {
 115         struct udf_sb_info *sbi = UDF_SB(sb);
 116         struct buffer_head *bh = NULL;
 117         struct udf_part_map *partmap;
 118         unsigned long block;
 119         unsigned long block_group;
 120         unsigned long bit;
 121         unsigned long i;
 122         int bitmap_nr;
 123         unsigned long overflow;
 124
 125         mutex_lock(&sbi->s_alloc_mutex);
 126         partmap = &sbi->s_partmaps[bloc->partitionReferenceNum];
 127         if (bloc->logicalBlockNum + count < count ||
 128             (bloc->logicalBlockNum + count) > partmap->s_partition_len) {
 129                 udf_debug("%d < %d || %d + %d > %d\n",
 130                           bloc->logicalBlockNum, 0, bloc->logicalBlockNum,
 131                           count, 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                         } else {
 161                                 udf_add_free_space(sb, sbi->s_partition, 1);
 162                         }
 163                 }
 164                 mark_buffer_dirty(bh);
 165                 if (overflow) {
 166                         block += count;
 167                         count = overflow;
 168                 }
 169         } while (overflow);
 170
 171 error_return:
 172         mutex_unlock(&sbi->s_alloc_mutex);
 173 }
 174
 175 static int udf_bitmap_prealloc_blocks(struct super_block *sb,
 176                                       struct inode *inode,
 177                                       struct udf_bitmap *bitmap,
 178                                       uint16_t partition, uint32_t first_block,
 179                                       uint32_t block_count)
 180 {
 181         struct udf_sb_info *sbi = UDF_SB(sb);
 182         int alloc_count = 0;
 183         int bit, block, block_group, group_start;
 184         int nr_groups, bitmap_nr;
 185         struct buffer_head *bh;
 186         __u32 part_len;
 187
 188         mutex_lock(&sbi->s_alloc_mutex);
 189         part_len = sbi->s_partmaps[partition].s_partition_len;
 190         if (first_block >= part_len)
 191                 goto out;
 192
 193         if (first_block + block_count > part_len)
 194                 block_count = part_len - first_block;
 195
 196         do {
 197                 nr_groups = udf_compute_nr_groups(sb, partition);
 198                 block = first_block + (sizeof(struct spaceBitmapDesc) << 3);
 199                 block_group = block >> (sb->s_blocksize_bits + 3);
 200                 group_start = block_group ? 0 : sizeof(struct spaceBitmapDesc);
 201
 202                 bitmap_nr = load_block_bitmap(sb, bitmap, block_group);
 203                 if (bitmap_nr < 0)
 204                         goto out;
 205                 bh = bitmap->s_block_bitmap[bitmap_nr];
 206
 207                 bit = block % (sb->s_blocksize << 3);
 208
 209                 while (bit < (sb->s_blocksize << 3) && block_count > 0) {
 210                         if (!udf_clear_bit(bit, bh->b_data))
 211                                 goto out;
 212                         block_count--;
 213                         alloc_count++;
 214                         bit++;
 215                         block++;
 216                 }
 217                 mark_buffer_dirty(bh);
 218         } while (block_count > 0);
 219
 220 out:
 221         udf_add_free_space(sb, partition, -alloc_count);
 222         mutex_unlock(&sbi->s_alloc_mutex);
 223         return alloc_count;
 224 }
 225
 226 static int udf_bitmap_new_block(struct super_block *sb,
 227                                 struct inode *inode,
 228                                 struct udf_bitmap *bitmap, uint16_t partition,
 229                                 uint32_t goal, int *err)
 230 {
 231         struct udf_sb_info *sbi = UDF_SB(sb);
 232         int newbit, bit = 0, block, block_group, group_start;
 233         int end_goal, nr_groups, bitmap_nr, i;
 234         struct buffer_head *bh = NULL;
 235         char *ptr;
 236         int newblock = 0;
 237
 238         *err = -ENOSPC;
 239         mutex_lock(&sbi->s_alloc_mutex);
 240
 241 repeat:
 242         if (goal >= sbi->s_partmaps[partition].s_partition_len)
 243                 goal = 0;
 244
 245         nr_groups = bitmap->s_nr_groups;
 246         block = goal + (sizeof(struct spaceBitmapDesc) << 3);
 247         block_group = block >> (sb->s_blocksize_bits + 3);
 248         group_start = block_group ? 0 : sizeof(struct spaceBitmapDesc);
 249
 250         bitmap_nr = load_block_bitmap(sb, bitmap, block_group);
 251         if (bitmap_nr < 0)
 252                 goto error_return;
 253         bh = bitmap->s_block_bitmap[bitmap_nr];
 254         ptr = memscan((char *)bh->b_data + group_start, 0xFF,
 255                       sb->s_blocksize - group_start);
 256
 257         if ((ptr - ((char *)bh->b_data)) < sb->s_blocksize) {
 258                 bit = block % (sb->s_blocksize << 3);
 259                 if (udf_test_bit(bit, bh->b_data))
 260                         goto got_block;
 261
 262                 end_goal = (bit + 63) & ~63;
 263                 bit = udf_find_next_one_bit(bh->b_data, end_goal, bit);
 264                 if (bit < end_goal)
 265                         goto got_block;
 266
 267                 ptr = memscan((char *)bh->b_data + (bit >> 3), 0xFF,
 268                               sb->s_blocksize - ((bit + 7) >> 3));
 269                 newbit = (ptr - ((char *)bh->b_data)) << 3;
 270                 if (newbit < sb->s_blocksize << 3) {
 271                         bit = newbit;
 272                         goto search_back;
 273                 }
 274
 275                 newbit = udf_find_next_one_bit(bh->b_data,
 276                                                sb->s_blocksize << 3, bit);
 277                 if (newbit < sb->s_blocksize << 3) {
 278                         bit = newbit;
 279                         goto got_block;
 280                 }
 281         }
 282
 283         for (i = 0; i < (nr_groups * 2); i++) {
 284                 block_group++;
 285                 if (block_group >= nr_groups)
 286                         block_group = 0;
 287                 group_start = block_group ? 0 : sizeof(struct spaceBitmapDesc);
 288
 289                 bitmap_nr = load_block_bitmap(sb, bitmap, block_group);
 290                 if (bitmap_nr < 0)
 291                         goto error_return;
 292                 bh = bitmap->s_block_bitmap[bitmap_nr];
 293                 if (i < nr_groups) {
 294                         ptr = memscan((char *)bh->b_data + group_start, 0xFF,
 295                                       sb->s_blocksize - group_start);
 296                         if ((ptr - ((char *)bh->b_data)) < sb->s_blocksize) {
 297                                 bit = (ptr - ((char *)bh->b_data)) << 3;
 298                                 break;
 299                         }
 300                 } else {
 301                         bit = udf_find_next_one_bit((char *)bh->b_data,
 302                                                     sb->s_blocksize << 3,
 303                                                     group_start << 3);
 304                         if (bit < sb->s_blocksize << 3)
 305                                 break;
 306                 }
 307         }
 308         if (i >= (nr_groups * 2)) {
 309                 mutex_unlock(&sbi->s_alloc_mutex);
 310                 return newblock;
 311         }
 312         if (bit < sb->s_blocksize << 3)
 313                 goto search_back;
 314         else
 315                 bit = udf_find_next_one_bit(bh->b_data, sb->s_blocksize << 3,
 316                                             group_start << 3);
 317         if (bit >= sb->s_blocksize << 3) {
 318                 mutex_unlock(&sbi->s_alloc_mutex);
 319                 return 0;
 320         }
 321
 322 search_back:
 323         i = 0;
 324         while (i < 7 && bit > (group_start << 3) &&
 325                udf_test_bit(bit - 1, bh->b_data)) {
 326                 ++i;
 327                 --bit;
 328         }
 329
 330 got_block:
 331         newblock = bit + (block_group << (sb->s_blocksize_bits + 3)) -
 332                 (sizeof(struct spaceBitmapDesc) << 3);
 333
 334         if (!udf_clear_bit(bit, bh->b_data)) {
 335                 udf_debug("bit already cleared for block %d\n", bit);
 336                 goto repeat;
 337         }
 338
 339         mark_buffer_dirty(bh);
 340
 341         udf_add_free_space(sb, partition, -1);
 342         mutex_unlock(&sbi->s_alloc_mutex);
 343         *err = 0;
 344         return newblock;
 345
 346 error_return:
 347         *err = -EIO;
 348         mutex_unlock(&sbi->s_alloc_mutex);
 349         return 0;
 350 }
 351
 352 static void udf_table_free_blocks(struct super_block *sb,
 353                                   struct inode *inode,
 354                                   struct inode *table,
 355                                   struct kernel_lb_addr *bloc,
 356                                   uint32_t offset,
 357                                   uint32_t count)
 358 {
 359         struct udf_sb_info *sbi = UDF_SB(sb);
 360         struct udf_part_map *partmap;
 361         uint32_t start, end;
 362         uint32_t elen;
 363         struct kernel_lb_addr eloc;
 364         struct extent_position oepos, epos;
 365         int8_t etype;
 366         int i;
 367         struct udf_inode_info *iinfo;
 368
 369         mutex_lock(&sbi->s_alloc_mutex);
 370         partmap = &sbi->s_partmaps[bloc->partitionReferenceNum];
 371         if (bloc->logicalBlockNum + count < count ||
 372             (bloc->logicalBlockNum + count) > partmap->s_partition_len) {
 373                 udf_debug("%d < %d || %d + %d > %d\n",
 374                           bloc->logicalBlockNum, 0, 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
 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
 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
 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
 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
 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 }