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((unsigned long *)(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                         }
 161                 }
 162                 udf_add_free_space(sb, sbi->s_partition, count);
 163                 mark_buffer_dirty(bh);
 164                 if (overflow) {
 165                         block += count;
 166                         count = overflow;
 167                 }
 168         } while (overflow);
 169
 170 error_return:
 171         mutex_unlock(&sbi->s_alloc_mutex);
 172 }
 173
 174 static int udf_bitmap_prealloc_blocks(struct super_block *sb,
 175                                       struct inode *inode,
 176                                       struct udf_bitmap *bitmap,
 177                                       uint16_t partition, uint32_t first_block,
 178                                       uint32_t block_count)
 179 {
 180         struct udf_sb_info *sbi = UDF_SB(sb);
 181         int alloc_count = 0;
 182         int bit, block, block_group, group_start;
 183         int nr_groups, bitmap_nr;
 184         struct buffer_head *bh;
 185         __u32 part_len;
 186
 187         mutex_lock(&sbi->s_alloc_mutex);
 188         part_len = sbi->s_partmaps[partition].s_partition_len;
 189         if (first_block >= part_len)
 190                 goto out;
 191
 192         if (first_block + block_count > part_len)
 193                 block_count = part_len - first_block;
 194
 195         do {
 196                 nr_groups = udf_compute_nr_groups(sb, partition);
 197                 block = first_block + (sizeof(struct spaceBitmapDesc) << 3);
 198                 block_group = block >> (sb->s_blocksize_bits + 3);
 199                 group_start = block_group ? 0 : sizeof(struct spaceBitmapDesc);
 200
 201                 bitmap_nr = load_block_bitmap(sb, bitmap, block_group);
 202                 if (bitmap_nr < 0)
 203                         goto out;
 204                 bh = bitmap->s_block_bitmap[bitmap_nr];
 205
 206                 bit = block % (sb->s_blocksize << 3);
 207
 208                 while (bit < (sb->s_blocksize << 3) && block_count > 0) {
 209                         if (!udf_clear_bit(bit, bh->b_data))
 210                                 goto out;
 211                         block_count--;
 212                         alloc_count++;
 213                         bit++;
 214                         block++;
 215                 }
 216                 mark_buffer_dirty(bh);
 217         } while (block_count > 0);
 218
 219 out:
 220         udf_add_free_space(sb, partition, -alloc_count);
 221         mutex_unlock(&sbi->s_alloc_mutex);
 222         return alloc_count;
 223 }
 224
 225 static int udf_bitmap_new_block(struct super_block *sb,
 226                                 struct inode *inode,
 227                                 struct udf_bitmap *bitmap, uint16_t partition,
 228                                 uint32_t goal, int *err)
 229 {
 230         struct udf_sb_info *sbi = UDF_SB(sb);
 231         int newbit, bit = 0, block, block_group, group_start;
 232         int end_goal, nr_groups, bitmap_nr, i;
 233         struct buffer_head *bh = NULL;
 234         char *ptr;
 235         int newblock = 0;
 236
 237         *err = -ENOSPC;
 238         mutex_lock(&sbi->s_alloc_mutex);
 239
 240 repeat:
 241         if (goal >= sbi->s_partmaps[partition].s_partition_len)
 242                 goal = 0;
 243
 244         nr_groups = bitmap->s_nr_groups;
 245         block = goal + (sizeof(struct spaceBitmapDesc) << 3);
 246         block_group = block >> (sb->s_blocksize_bits + 3);
 247         group_start = block_group ? 0 : sizeof(struct spaceBitmapDesc);
 248
 249         bitmap_nr = load_block_bitmap(sb, bitmap, block_group);
 250         if (bitmap_nr < 0)
 251                 goto error_return;
 252         bh = bitmap->s_block_bitmap[bitmap_nr];
 253         ptr = memscan((char *)bh->b_data + group_start, 0xFF,
 254                       sb->s_blocksize - group_start);
 255
 256         if ((ptr - ((char *)bh->b_data)) < sb->s_blocksize) {
 257                 bit = block % (sb->s_blocksize << 3);
 258                 if (udf_test_bit(bit, bh->b_data))
 259                         goto got_block;
 260
 261                 end_goal = (bit + 63) & ~63;
 262                 bit = udf_find_next_one_bit(bh->b_data, end_goal, bit);
 263                 if (bit < end_goal)
 264                         goto got_block;
 265
 266                 ptr = memscan((char *)bh->b_data + (bit >> 3), 0xFF,
 267                               sb->s_blocksize - ((bit + 7) >> 3));
 268                 newbit = (ptr - ((char *)bh->b_data)) << 3;
 269                 if (newbit < sb->s_blocksize << 3) {
 270                         bit = newbit;
 271                         goto search_back;
 272                 }
 273
 274                 newbit = udf_find_next_one_bit(bh->b_data,
 275                                                sb->s_blocksize << 3, bit);
 276                 if (newbit < sb->s_blocksize << 3) {
 277                         bit = newbit;
 278                         goto got_block;
 279                 }
 280         }
 281
 282         for (i = 0; i < (nr_groups * 2); i++) {
 283                 block_group++;
 284                 if (block_group >= nr_groups)
 285                         block_group = 0;
 286                 group_start = block_group ? 0 : sizeof(struct spaceBitmapDesc);
 287
 288                 bitmap_nr = load_block_bitmap(sb, bitmap, block_group);
 289                 if (bitmap_nr < 0)
 290                         goto error_return;
 291                 bh = bitmap->s_block_bitmap[bitmap_nr];
 292                 if (i < nr_groups) {
 293                         ptr = memscan((char *)bh->b_data + group_start, 0xFF,
 294                                       sb->s_blocksize - group_start);
 295                         if ((ptr - ((char *)bh->b_data)) < sb->s_blocksize) {
 296                                 bit = (ptr - ((char *)bh->b_data)) << 3;
 297                                 break;
 298                         }
 299                 } else {
 300                         bit = udf_find_next_one_bit(bh->b_data,
 301                                                     sb->s_blocksize << 3,
 302                                                     group_start << 3);
 303                         if (bit < sb->s_blocksize << 3)
 304                                 break;
 305                 }
 306         }
 307         if (i >= (nr_groups * 2)) {
 308                 mutex_unlock(&sbi->s_alloc_mutex);
 309                 return newblock;
 310         }
 311         if (bit < sb->s_blocksize << 3)
 312                 goto search_back;
 313         else
 314                 bit = udf_find_next_one_bit(bh->b_data, sb->s_blocksize << 3,
 315                                             group_start << 3);
 316         if (bit >= sb->s_blocksize << 3) {
 317                 mutex_unlock(&sbi->s_alloc_mutex);
 318                 return 0;
 319         }
 320
 321 search_back:
 322         i = 0;
 323         while (i < 7 && bit > (group_start << 3) &&
 324                udf_test_bit(bit - 1, bh->b_data)) {
 325                 ++i;
 326                 --bit;
 327         }
 328
 329 got_block:
 330         newblock = bit + (block_group << (sb->s_blocksize_bits + 3)) -
 331                 (sizeof(struct spaceBitmapDesc) << 3);
 332
 333         if (!udf_clear_bit(bit, bh->b_data)) {
 334                 udf_debug("bit already cleared for block %d\n", bit);
 335                 goto repeat;
 336         }
 337
 338         mark_buffer_dirty(bh);
 339
 340         udf_add_free_space(sb, partition, -1);
 341         mutex_unlock(&sbi->s_alloc_mutex);
 342         *err = 0;
 343         return newblock;
 344
 345 error_return:
 346         *err = -EIO;
 347         mutex_unlock(&sbi->s_alloc_mutex);
 348         return 0;
 349 }
 350
 351 static void udf_table_free_blocks(struct super_block *sb,
 352                                   struct inode *inode,
 353                                   struct inode *table,
 354                                   struct kernel_lb_addr *bloc,
 355                                   uint32_t offset,
 356                                   uint32_t count)
 357 {
 358         struct udf_sb_info *sbi = UDF_SB(sb);
 359         struct udf_part_map *partmap;
 360         uint32_t start, end;
 361         uint32_t elen;
 362         struct kernel_lb_addr eloc;
 363         struct extent_position oepos, epos;
 364         int8_t etype;
 365         int i;
 366         struct udf_inode_info *iinfo;
 367
 368         mutex_lock(&sbi->s_alloc_mutex);
 369         partmap = &sbi->s_partmaps[bloc->partitionReferenceNum];
 370         if (bloc->logicalBlockNum + count < count ||
 371             (bloc->logicalBlockNum + count) > partmap->s_partition_len) {
 372                 udf_debug("%d < %d || %d + %d > %d\n",
 373                           bloc->logicalBlockNum, 0, bloc->logicalBlockNum, count,
 374                           partmap->s_partition_len);
 375                 goto error_return;
 376         }
 377
 378         iinfo = UDF_I(table);
 379         udf_add_free_space(sb, sbi->s_partition, count);
 380
 381         start = bloc->logicalBlockNum + offset;
 382         end = bloc->logicalBlockNum + offset + count - 1;
 383
 384         epos.offset = oepos.offset = sizeof(struct unallocSpaceEntry);
 385         elen = 0;
 386         epos.block = oepos.block = iinfo->i_location;
 387         epos.bh = oepos.bh = NULL;
 388
 389         while (count &&
 390                (etype = udf_next_aext(table, &epos, &eloc, &elen, 1)) != -1) {
 391                 if (((eloc.logicalBlockNum +
 392                         (elen >> sb->s_blocksize_bits)) == start)) {
 393                         if ((0x3FFFFFFF - elen) <
 394                                         (count << sb->s_blocksize_bits)) {
 395                                 uint32_t tmp = ((0x3FFFFFFF - elen) >>
 396                                                         sb->s_blocksize_bits);
 397                                 count -= tmp;
 398                                 start += tmp;
 399                                 elen = (etype << 30) |
 400                                         (0x40000000 - sb->s_blocksize);
 401                         } else {
 402                                 elen = (etype << 30) |
 403                                         (elen +
 404                                         (count << sb->s_blocksize_bits));
 405                                 start += count;
 406                                 count = 0;
 407                         }
 408                         udf_write_aext(table, &oepos, &eloc, elen, 1);
 409                 } else if (eloc.logicalBlockNum == (end + 1)) {
 410                         if ((0x3FFFFFFF - elen) <
 411                                         (count << sb->s_blocksize_bits)) {
 412                                 uint32_t tmp = ((0x3FFFFFFF - elen) >>
 413                                                 sb->s_blocksize_bits);
 414                                 count -= tmp;
 415                                 end -= tmp;
 416                                 eloc.logicalBlockNum -= tmp;
 417                                 elen = (etype << 30) |
 418                                         (0x40000000 - sb->s_blocksize);
 419                         } else {
 420                                 eloc.logicalBlockNum = start;
 421                                 elen = (etype << 30) |
 422                                         (elen +
 423                                         (count << sb->s_blocksize_bits));
 424                                 end -= count;
 425                                 count = 0;
 426                         }
 427                         udf_write_aext(table, &oepos, &eloc, elen, 1);
 428                 }
 429
 430                 if (epos.bh != oepos.bh) {
 431                         i = -1;
 432                         oepos.block = epos.block;
 433                         brelse(oepos.bh);
 434                         get_bh(epos.bh);
 435                         oepos.bh = epos.bh;
 436                         oepos.offset = 0;
 437                 } else {
 438                         oepos.offset = epos.offset;
 439                 }
 440         }
 441
 442         if (count) {
 443                 /*
 444                  * NOTE: we CANNOT use udf_add_aext here, as it can try to
 445                  * allocate a new block, and since we hold the super block
 446                  * lock already very bad things would happen :)
 447                  *
 448                  * We copy the behavior of udf_add_aext, but instead of
 449                  * trying to allocate a new block close to the existing one,
 450                  * we just steal a block from the extent we are trying to add.
 451                  *
 452                  * It would be nice if the blocks were close together, but it
 453                  * isn't required.
 454                  */
 455
 456                 int adsize;
 457                 struct short_ad *sad = NULL;
 458                 struct long_ad *lad = NULL;
 459                 struct allocExtDesc *aed;
 460
 461                 eloc.logicalBlockNum = start;
 462                 elen = EXT_RECORDED_ALLOCATED |
 463                         (count << sb->s_blocksize_bits);
 464
 465                 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
 466                         adsize = sizeof(struct short_ad);
 467                 else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
 468                         adsize = sizeof(struct long_ad);
 469                 else {
 470                         brelse(oepos.bh);
 471                         brelse(epos.bh);
 472                         goto error_return;
 473                 }
 474
 475                 if (epos.offset + (2 * adsize) > sb->s_blocksize) {
 476                         unsigned char *sptr, *dptr;
 477                         int loffset;
 478
 479                         brelse(oepos.bh);
 480                         oepos = epos;
 481
 482                         /* Steal a block from the extent being free'd */
 483                         epos.block.logicalBlockNum = eloc.logicalBlockNum;
 484                         eloc.logicalBlockNum++;
 485                         elen -= sb->s_blocksize;
 486
 487                         epos.bh = udf_tread(sb,
 488                                         udf_get_lb_pblock(sb, &epos.block, 0));
 489                         if (!epos.bh) {
 490                                 brelse(oepos.bh);
 491                                 goto error_return;
 492                         }
 493                         aed = (struct allocExtDesc *)(epos.bh->b_data);
 494                         aed->previousAllocExtLocation =
 495                                 cpu_to_le32(oepos.block.logicalBlockNum);
 496                         if (epos.offset + adsize > sb->s_blocksize) {
 497                                 loffset = epos.offset;
 498                                 aed->lengthAllocDescs = cpu_to_le32(adsize);
 499                                 sptr = iinfo->i_ext.i_data + epos.offset
 500                                                                 - adsize;
 501                                 dptr = epos.bh->b_data +
 502                                         sizeof(struct allocExtDesc);
 503                                 memcpy(dptr, sptr, adsize);
 504                                 epos.offset = sizeof(struct allocExtDesc) +
 505                                                 adsize;
 506                         } else {
 507                                 loffset = epos.offset + adsize;
 508                                 aed->lengthAllocDescs = cpu_to_le32(0);
 509                                 if (oepos.bh) {
 510                                         sptr = oepos.bh->b_data + epos.offset;
 511                                         aed = (struct allocExtDesc *)
 512                                                 oepos.bh->b_data;
 513                                         le32_add_cpu(&aed->lengthAllocDescs,
 514                                                         adsize);
 515                                 } else {
 516                                         sptr = iinfo->i_ext.i_data +
 517                                                                 epos.offset;
 518                                         iinfo->i_lenAlloc += adsize;
 519                                         mark_inode_dirty(table);
 520                                 }
 521                                 epos.offset = sizeof(struct allocExtDesc);
 522                         }
 523                         if (sbi->s_udfrev >= 0x0200)
 524                                 udf_new_tag(epos.bh->b_data, TAG_IDENT_AED,
 525                                             3, 1, epos.block.logicalBlockNum,
 526                                             sizeof(struct tag));
 527                         else
 528                                 udf_new_tag(epos.bh->b_data, TAG_IDENT_AED,
 529                                             2, 1, epos.block.logicalBlockNum,
 530                                             sizeof(struct tag));
 531
 532                         switch (iinfo->i_alloc_type) {
 533                         case ICBTAG_FLAG_AD_SHORT:
 534                                 sad = (struct short_ad *)sptr;
 535                                 sad->extLength = cpu_to_le32(
 536                                         EXT_NEXT_EXTENT_ALLOCDECS |
 537                                         sb->s_blocksize);
 538                                 sad->extPosition =
 539                                         cpu_to_le32(epos.block.logicalBlockNum);
 540                                 break;
 541                         case ICBTAG_FLAG_AD_LONG:
 542                                 lad = (struct long_ad *)sptr;
 543                                 lad->extLength = cpu_to_le32(
 544                                         EXT_NEXT_EXTENT_ALLOCDECS |
 545                                         sb->s_blocksize);
 546                                 lad->extLocation =
 547                                         cpu_to_lelb(epos.block);
 548                                 break;
 549                         }
 550                         if (oepos.bh) {
 551                                 udf_update_tag(oepos.bh->b_data, loffset);
 552                                 mark_buffer_dirty(oepos.bh);
 553                         } else {
 554                                 mark_inode_dirty(table);
 555                         }
 556                 }
 557
 558                 /* It's possible that stealing the block emptied the extent */
 559                 if (elen) {
 560                         udf_write_aext(table, &epos, &eloc, elen, 1);
 561
 562                         if (!epos.bh) {
 563                                 iinfo->i_lenAlloc += adsize;
 564                                 mark_inode_dirty(table);
 565                         } else {
 566                                 aed = (struct allocExtDesc *)epos.bh->b_data;
 567                                 le32_add_cpu(&aed->lengthAllocDescs, adsize);
 568                                 udf_update_tag(epos.bh->b_data, epos.offset);
 569                                 mark_buffer_dirty(epos.bh);
 570                         }
 571                 }
 572         }
 573
 574         brelse(epos.bh);
 575         brelse(oepos.bh);
 576
 577 error_return:
 578         mutex_unlock(&sbi->s_alloc_mutex);
 579         return;
 580 }
 581
 582 static int udf_table_prealloc_blocks(struct super_block *sb,
 583                                      struct inode *inode,
 584                                      struct inode *table, uint16_t partition,
 585                                      uint32_t first_block, uint32_t block_count)
 586 {
 587         struct udf_sb_info *sbi = UDF_SB(sb);
 588         int alloc_count = 0;
 589         uint32_t elen, adsize;
 590         struct kernel_lb_addr eloc;
 591         struct extent_position epos;
 592         int8_t etype = -1;
 593         struct udf_inode_info *iinfo;
 594
 595         if (first_block >= sbi->s_partmaps[partition].s_partition_len)
 596                 return 0;
 597
 598         iinfo = UDF_I(table);
 599         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
 600                 adsize = sizeof(struct short_ad);
 601         else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
 602                 adsize = sizeof(struct long_ad);
 603         else
 604                 return 0;
 605
 606         mutex_lock(&sbi->s_alloc_mutex);
 607         epos.offset = sizeof(struct unallocSpaceEntry);
 608         epos.block = iinfo->i_location;
 609         epos.bh = NULL;
 610         eloc.logicalBlockNum = 0xFFFFFFFF;
 611
 612         while (first_block != eloc.logicalBlockNum &&
 613                (etype = udf_next_aext(table, &epos, &eloc, &elen, 1)) != -1) {
 614                 udf_debug("eloc=%d, elen=%d, first_block=%d\n",
 615                           eloc.logicalBlockNum, elen, first_block);
 616                 ; /* empty loop body */
 617         }
 618
 619         if (first_block == eloc.logicalBlockNum) {
 620                 epos.offset -= adsize;
 621
 622                 alloc_count = (elen >> sb->s_blocksize_bits);
 623                 if (alloc_count > block_count) {
 624                         alloc_count = block_count;
 625                         eloc.logicalBlockNum += alloc_count;
 626                         elen -= (alloc_count << sb->s_blocksize_bits);
 627                         udf_write_aext(table, &epos, &eloc,
 628                                         (etype << 30) | elen, 1);
 629                 } else
 630                         udf_delete_aext(table, epos, eloc,
 631                                         (etype << 30) | elen);
 632         } else {
 633                 alloc_count = 0;
 634         }
 635
 636         brelse(epos.bh);
 637
 638         if (alloc_count)
 639                 udf_add_free_space(sb, partition, -alloc_count);
 640         mutex_unlock(&sbi->s_alloc_mutex);
 641         return alloc_count;
 642 }
 643
 644 static int udf_table_new_block(struct super_block *sb,
 645                                struct inode *inode,
 646                                struct inode *table, uint16_t partition,
 647                                uint32_t goal, int *err)
 648 {
 649         struct udf_sb_info *sbi = UDF_SB(sb);
 650         uint32_t spread = 0xFFFFFFFF, nspread = 0xFFFFFFFF;
 651         uint32_t newblock = 0, adsize;
 652         uint32_t elen, goal_elen = 0;
 653         struct kernel_lb_addr eloc, uninitialized_var(goal_eloc);
 654         struct extent_position epos, goal_epos;
 655         int8_t etype;
 656         struct udf_inode_info *iinfo = UDF_I(table);
 657
 658         *err = -ENOSPC;
 659
 660         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
 661                 adsize = sizeof(struct short_ad);
 662         else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
 663                 adsize = sizeof(struct long_ad);
 664         else
 665                 return newblock;
 666
 667         mutex_lock(&sbi->s_alloc_mutex);
 668         if (goal >= sbi->s_partmaps[partition].s_partition_len)
 669                 goal = 0;
 670
 671         /* We search for the closest matching block to goal. If we find
 672            a exact hit, we stop. Otherwise we keep going till we run out
 673            of extents. We store the buffer_head, bloc, and extoffset
 674            of the current closest match and use that when we are done.
 675          */
 676         epos.offset = sizeof(struct unallocSpaceEntry);
 677         epos.block = iinfo->i_location;
 678         epos.bh = goal_epos.bh = NULL;
 679
 680         while (spread &&
 681                (etype = udf_next_aext(table, &epos, &eloc, &elen, 1)) != -1) {
 682                 if (goal >= eloc.logicalBlockNum) {
 683                         if (goal < eloc.logicalBlockNum +
 684                                         (elen >> sb->s_blocksize_bits))
 685                                 nspread = 0;
 686                         else
 687                                 nspread = goal - eloc.logicalBlockNum -
 688                                         (elen >> sb->s_blocksize_bits);
 689                 } else {
 690                         nspread = eloc.logicalBlockNum - goal;
 691                 }
 692
 693                 if (nspread < spread) {
 694                         spread = nspread;
 695                         if (goal_epos.bh != epos.bh) {
 696                                 brelse(goal_epos.bh);
 697                                 goal_epos.bh = epos.bh;
 698                                 get_bh(goal_epos.bh);
 699                         }
 700                         goal_epos.block = epos.block;
 701                         goal_epos.offset = epos.offset - adsize;
 702                         goal_eloc = eloc;
 703                         goal_elen = (etype << 30) | elen;
 704                 }
 705         }
 706
 707         brelse(epos.bh);
 708
 709         if (spread == 0xFFFFFFFF) {
 710                 brelse(goal_epos.bh);
 711                 mutex_unlock(&sbi->s_alloc_mutex);
 712                 return 0;
 713         }
 714
 715         /* Only allocate blocks from the beginning of the extent.
 716            That way, we only delete (empty) extents, never have to insert an
 717            extent because of splitting */
 718         /* This works, but very poorly.... */
 719
 720         newblock = goal_eloc.logicalBlockNum;
 721         goal_eloc.logicalBlockNum++;
 722         goal_elen -= sb->s_blocksize;
 723
 724         if (goal_elen)
 725                 udf_write_aext(table, &goal_epos, &goal_eloc, goal_elen, 1);
 726         else
 727                 udf_delete_aext(table, goal_epos, goal_eloc, goal_elen);
 728         brelse(goal_epos.bh);
 729
 730         udf_add_free_space(sb, partition, -1);
 731
 732         mutex_unlock(&sbi->s_alloc_mutex);
 733         *err = 0;
 734         return newblock;
 735 }
 736
 737 void udf_free_blocks(struct super_block *sb, struct inode *inode,
 738                      struct kernel_lb_addr *bloc, uint32_t offset,
 739                      uint32_t count)
 740 {
 741         uint16_t partition = bloc->partitionReferenceNum;
 742         struct udf_part_map *map = &UDF_SB(sb)->s_partmaps[partition];
 743
 744         if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_BITMAP) {
 745                 udf_bitmap_free_blocks(sb, inode, map->s_uspace.s_bitmap,
 746                                        bloc, offset, count);
 747         } else if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_TABLE) {
 748                 udf_table_free_blocks(sb, inode, map->s_uspace.s_table,
 749                                       bloc, offset, count);
 750         } else if (map->s_partition_flags & UDF_PART_FLAG_FREED_BITMAP) {
 751                 udf_bitmap_free_blocks(sb, inode, map->s_fspace.s_bitmap,
 752                                        bloc, offset, count);
 753         } else if (map->s_partition_flags & UDF_PART_FLAG_FREED_TABLE) {
 754                 udf_table_free_blocks(sb, inode, map->s_fspace.s_table,
 755                                       bloc, offset, count);
 756         }
 757 }
 758
 759 inline int udf_prealloc_blocks(struct super_block *sb,
 760                                struct inode *inode,
 761                                uint16_t partition, uint32_t first_block,
 762                                uint32_t block_count)
 763 {
 764         struct udf_part_map *map = &UDF_SB(sb)->s_partmaps[partition];
 765
 766         if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_BITMAP)
 767                 return udf_bitmap_prealloc_blocks(sb, inode,
 768                                                   map->s_uspace.s_bitmap,
 769                                                   partition, first_block,
 770                                                   block_count);
 771         else if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_TABLE)
 772                 return udf_table_prealloc_blocks(sb, inode,
 773                                                  map->s_uspace.s_table,
 774                                                  partition, first_block,
 775                                                  block_count);
 776         else if (map->s_partition_flags & UDF_PART_FLAG_FREED_BITMAP)
 777                 return udf_bitmap_prealloc_blocks(sb, inode,
 778                                                   map->s_fspace.s_bitmap,
 779                                                   partition, first_block,
 780                                                   block_count);
 781         else if (map->s_partition_flags & UDF_PART_FLAG_FREED_TABLE)
 782                 return udf_table_prealloc_blocks(sb, inode,
 783                                                  map->s_fspace.s_table,
 784                                                  partition, first_block,
 785                                                  block_count);
 786         else
 787                 return 0;
 788 }
 789
 790 inline int udf_new_block(struct super_block *sb,
 791                          struct inode *inode,
 792                          uint16_t partition, uint32_t goal, int *err)
 793 {
 794         struct udf_part_map *map = &UDF_SB(sb)->s_partmaps[partition];
 795
 796         if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_BITMAP)
 797                 return udf_bitmap_new_block(sb, inode,
 798                                            map->s_uspace.s_bitmap,
 799                                            partition, goal, err);
 800         else if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_TABLE)
 801                 return udf_table_new_block(sb, inode,
 802                                            map->s_uspace.s_table,
 803                                            partition, goal, err);
 804         else if (map->s_partition_flags & UDF_PART_FLAG_FREED_BITMAP)
 805                 return udf_bitmap_new_block(sb, inode,
 806                                             map->s_fspace.s_bitmap,
 807                                             partition, goal, err);
 808         else if (map->s_partition_flags & UDF_PART_FLAG_FREED_TABLE)
 809                 return udf_table_new_block(sb, inode,
 810                                            map->s_fspace.s_table,
 811                                            partition, goal, err);
 812         else {
 813                 *err = -EIO;
 814                 return 0;
 815         }
 816 }