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