fs/udf/balloc.c

   1 /*
   2  * balloc.c
   3  *
   4  * PURPOSE
   5  *      Block allocation handling routines for the OSTA-UDF(tm) filesystem.
   6  *
   7  * CONTACTS
   8  *      E-mail regarding any portion of the Linux UDF file system should be
   9  *      directed to the development team mailing list (run by majordomo):
  10  *              linux_udf@hootie.lvld.hp.com
  11  *
  12  * COPYRIGHT
  13  *      This file is distributed under the terms of the GNU General Public
  14  *      License (GPL). Copies of the GPL can be obtained from:
  15  *              ftp://prep.ai.mit.edu/pub/gnu/GPL
  16  *      Each contributing author retains all rights to their own work.
  17  *
  18  *  (C) 1999 Ben Fennema
  19  *  (C) 1999 Stelias Computing Inc
  20  *
  21  * HISTORY
  22  *
  23  *  02/24/99 blf  Created.
  24  *
  25  */
  26
  27 #include "udfdecl.h"
  28 #include <linux/fs.h>
  29 #include <linux/locks.h>
  30 #include <linux/udf_fs.h>
  31
  32 #include <asm/bitops.h>
  33
  34 #include "udf_i.h"
  35 #include "udf_sb.h"
  36
  37 static int read_block_bitmap(struct super_block * sb, unsigned int block,
  38         unsigned long bitmap_nr)
  39 {
  40         struct buffer_head *bh = NULL;
  41         int retval = 0;
  42         lb_addr loc;
  43
  44         loc.logicalBlockNum = UDF_SB_PARTMAPS(sb)[UDF_SB_PARTITION(sb)].s_uspace_bitmap;
  45         loc.partitionReferenceNum = UDF_SB_PARTITION(sb);
  46
  47         bh = udf_tread(sb, udf_get_lb_pblock(sb, loc, block), sb->s_blocksize);
  48         if (!bh)
  49         {
  50                 retval = -EIO;
  51         }
  52         UDF_SB_BLOCK_BITMAP_NUMBER(sb, bitmap_nr) = block;
  53         UDF_SB_BLOCK_BITMAP(sb, bitmap_nr) = bh;
  54         return retval;
  55 }
  56
  57 static int load__block_bitmap(struct super_block * sb, unsigned int block_group)
  58 {
  59         int i, j, retval = 0;
  60         unsigned long block_bitmap_number;
  61         struct buffer_head * block_bitmap = NULL;
  62         int nr_groups = (UDF_SB_PARTLEN(sb, UDF_SB_PARTITION(sb)) +
  63                 (sizeof(struct SpaceBitmapDesc) << 3) + (sb->s_blocksize * 8) - 1) / (sb->s_blocksize * 8);
  64
  65         if (block_group >= nr_groups)
  66         {
  67                 udf_debug("block_group (%d) > nr_groups (%d)\n", block_group, nr_groups);
  68         }
  69
  70         if (nr_groups <= UDF_MAX_BLOCK_LOADED)
  71         {
  72                 if (UDF_SB_BLOCK_BITMAP(sb, block_group))
  73                 {
  74                         if (UDF_SB_BLOCK_BITMAP_NUMBER(sb, block_group) == block_group)
  75                                 return block_group;
  76                 }
  77                 retval = read_block_bitmap(sb, block_group, block_group);
  78                 if (retval < 0)
  79                         return retval;
  80                 return block_group;
  81         }
  82
  83         for (i=0; i<UDF_SB_LOADED_BLOCK_BITMAPS(sb) &&
  84                 UDF_SB_BLOCK_BITMAP_NUMBER(sb, i) != block_group; i++)
  85         {
  86                 ;
  87         }
  88         if (i < UDF_SB_LOADED_BLOCK_BITMAPS(sb) &&
  89                 UDF_SB_BLOCK_BITMAP_NUMBER(sb, i) == block_group)
  90         {
  91                 block_bitmap_number = UDF_SB_BLOCK_BITMAP_NUMBER(sb, i);
  92                 block_bitmap = UDF_SB_BLOCK_BITMAP(sb, i);
  93                 for (j=i; j>0; j--)
  94                 {
  95                         UDF_SB_BLOCK_BITMAP_NUMBER(sb, j) = UDF_SB_BLOCK_BITMAP_NUMBER(sb, j-1);
  96                         UDF_SB_BLOCK_BITMAP(sb, j) = UDF_SB_BLOCK_BITMAP(sb, j-1);
  97                 }
  98                 UDF_SB_BLOCK_BITMAP_NUMBER(sb, 0) = block_bitmap_number;
  99                 UDF_SB_BLOCK_BITMAP(sb, 0) = block_bitmap;
 100
 101                 if (!block_bitmap)
 102                         retval = read_block_bitmap(sb, block_group, 0);
 103         }
 104         else
 105         {
 106                 if (UDF_SB_LOADED_BLOCK_BITMAPS(sb) < UDF_MAX_BLOCK_LOADED)
 107                         UDF_SB_LOADED_BLOCK_BITMAPS(sb) ++;
 108                 else
 109                         brelse(UDF_SB_BLOCK_BITMAP(sb, UDF_MAX_BLOCK_LOADED-1));
 110                 for (j=UDF_SB_LOADED_BLOCK_BITMAPS(sb)-1; j>0; j--)
 111                 {
 112                         UDF_SB_BLOCK_BITMAP_NUMBER(sb, j) = UDF_SB_BLOCK_BITMAP_NUMBER(sb, j-1);
 113                         UDF_SB_BLOCK_BITMAP(sb, j) = UDF_SB_BLOCK_BITMAP(sb, j-1);
 114                 }
 115                 retval = read_block_bitmap(sb, block_group, 0);
 116         }
 117         return retval;
 118 }
 119
 120 static inline int load_block_bitmap(struct super_block *sb,
 121         unsigned int block_group)
 122 {
 123         int slot;
 124     int nr_groups = (UDF_SB_PARTLEN(sb, UDF_SB_PARTITION(sb)) +
 125         (sizeof(struct SpaceBitmapDesc) << 3) + (sb->s_blocksize * 8) - 1) / (sb->s_blocksize * 8);
 126
 127         if (UDF_SB_LOADED_BLOCK_BITMAPS(sb) > 0 &&
 128                 UDF_SB_BLOCK_BITMAP_NUMBER(sb, 0) == block_group &&
 129                 UDF_SB_BLOCK_BITMAP(sb, block_group))
 130         {
 131                 return 0;
 132         }
 133         else if (nr_groups <= UDF_MAX_BLOCK_LOADED &&
 134                 UDF_SB_BLOCK_BITMAP_NUMBER(sb, block_group) == block_group &&
 135                 UDF_SB_BLOCK_BITMAP(sb, block_group))
 136         {
 137                 slot = block_group;
 138         }
 139         else
 140         {
 141                 slot = load__block_bitmap(sb, block_group);
 142         }
 143
 144         if (slot < 0)
 145                 return slot;
 146
 147         if (!UDF_SB_BLOCK_BITMAP(sb, slot))
 148                 return -EIO;
 149
 150         return slot;
 151 }
 152
 153 void udf_free_blocks(const struct inode * inode, lb_addr bloc, Uint32 offset,
 154         Uint32 count)
 155 {
 156         struct buffer_head * bh = NULL;
 157         unsigned long block;
 158         unsigned long block_group;
 159         unsigned long bit;
 160         unsigned long i;
 161         int bitmap_nr;
 162         unsigned long overflow;
 163         struct super_block * sb;
 164
 165         sb = inode->i_sb;
 166         if (!sb)
 167         {
 168                 udf_debug("nonexistent device");
 169                 return;
 170         }
 171
 172         if (UDF_SB_PARTMAPS(sb)[bloc.partitionReferenceNum].s_uspace_bitmap == 0xFFFFFFFF)
 173                 return;
 174
 175         lock_super(sb);
 176         if (bloc.logicalBlockNum < 0 ||
 177                 (bloc.logicalBlockNum + count) > UDF_SB_PARTLEN(sb, bloc.partitionReferenceNum))
 178         {
 179                 udf_debug("%d < %d || %d + %d > %d\n",
 180                         bloc.logicalBlockNum, 0, bloc.logicalBlockNum, count,
 181                         UDF_SB_PARTLEN(sb, bloc.partitionReferenceNum));
 182                 goto error_return;
 183         }
 184
 185         block = bloc.logicalBlockNum + offset + (sizeof(struct SpaceBitmapDesc) << 3);
 186
 187 do_more:
 188         overflow = 0;
 189         block_group = block >> (sb->s_blocksize_bits + 3);
 190         bit = block % (sb->s_blocksize << 3);
 191
 192         /*
 193          * Check to see if we are freeing blocks across a group boundary.
 194          */
 195         if (bit + count > (sb->s_blocksize << 3))
 196         {
 197                 overflow = bit + count - (sb->s_blocksize << 3);
 198                 count -= overflow;
 199         }
 200         bitmap_nr = load_block_bitmap(sb, block_group);
 201         if (bitmap_nr < 0)
 202                 goto error_return;
 203
 204         bh = UDF_SB_BLOCK_BITMAP(sb, bitmap_nr);
 205         for (i=0; i < count; i++)
 206         {
 207                 if (udf_set_bit(bit + i, bh->b_data))
 208                 {
 209                         udf_debug("bit %ld already set\n", bit + i);
 210                         udf_debug("byte=%2x\n", ((char *)bh->b_data)[(bit + i) >> 3]);
 211                 }
 212                 else if (UDF_SB_LVIDBH(sb))
 213                 {
 214                         UDF_SB_LVID(sb)->freeSpaceTable[UDF_SB_PARTITION(sb)] =
 215                                 cpu_to_le32(le32_to_cpu(UDF_SB_LVID(sb)->freeSpaceTable[UDF_SB_PARTITION(sb)])+1);
 216                 }
 217         }
 218         mark_buffer_dirty(bh, 1);
 219         if (overflow)
 220         {
 221                 block += count;
 222                 count = overflow;
 223                 goto do_more;
 224         }
 225 error_return:
 226         sb->s_dirt = 1;
 227         if (UDF_SB_LVIDBH(sb))
 228                 mark_buffer_dirty(UDF_SB_LVIDBH(sb), 1);
 229         unlock_super(sb);
 230         return;
 231 }
 232
 233 int udf_alloc_blocks(const struct inode * inode, Uint16 partition,
 234         Uint32 first_block, Uint32 block_count)
 235 {
 236         int alloc_count = 0;
 237         int bit, block, block_group, group_start;
 238         int nr_groups, bitmap_nr;
 239         struct buffer_head *bh;
 240         struct super_block *sb;
 241
 242         sb = inode->i_sb;
 243         if (!sb)
 244         {
 245                 udf_debug("nonexistent device\n");
 246                 return 0;
 247         }
 248         lock_super(sb);
 249
 250         if (first_block < 0 || first_block >= UDF_SB_PARTLEN(sb, partition))
 251                 goto out;
 252
 253 repeat:
 254         nr_groups = (UDF_SB_PARTLEN(sb, partition) +
 255                 (sizeof(struct SpaceBitmapDesc) << 3) + (sb->s_blocksize * 8) - 1) / (sb->s_blocksize * 8);
 256         block = first_block + (sizeof(struct SpaceBitmapDesc) << 3);
 257         block_group = block >> (sb->s_blocksize_bits + 3);
 258         group_start = block_group ? 0 : sizeof(struct SpaceBitmapDesc);
 259
 260         bitmap_nr = load_block_bitmap(sb, block_group);
 261         if (bitmap_nr < 0)
 262                 goto out;
 263         bh = UDF_SB_BLOCK_BITMAP(sb, bitmap_nr);
 264
 265         bit = block % (sb->s_blocksize << 3);
 266
 267         while (bit < (sb->s_blocksize << 3) && block_count > 0)
 268         {
 269                 if (!udf_test_bit(bit, bh->b_data))
 270                         goto out;
 271                 if (!udf_clear_bit(bit, bh->b_data))
 272                 {
 273                         udf_debug("bit already cleared for block %d\n", bit);
 274                         goto out;
 275                 }
 276                 block_count --;
 277                 alloc_count ++;
 278                 bit ++;
 279                 block ++;
 280
 281         }
 282         mark_buffer_dirty(bh, 1);
 283         if (block_count > 0)
 284                 goto repeat;
 285 out:
 286         if (UDF_SB_LVIDBH(sb))
 287         {
 288                 UDF_SB_LVID(sb)->freeSpaceTable[partition] =
 289                         cpu_to_le32(le32_to_cpu(UDF_SB_LVID(sb)->freeSpaceTable[partition])-alloc_count);
 290                 mark_buffer_dirty(UDF_SB_LVIDBH(sb), 1);
 291         }
 292         sb->s_dirt = 1;
 293         unlock_super(sb);
 294         return alloc_count;
 295 }
 296
 297 int udf_new_block(const struct inode * inode, Uint16 partition, Uint32 goal, int *err)
 298 {
 299         int tmp, newbit, bit=0, block, block_group, group_start;
 300         int end_goal, nr_groups, bitmap_nr, i;
 301         struct buffer_head *bh = NULL;
 302         struct super_block *sb;
 303         char *ptr;
 304         int newblock = 0;
 305
 306         *err = -ENOSPC;
 307         sb = inode->i_sb;
 308         if (!sb)
 309         {
 310                 udf_debug("nonexistent device\n");
 311                 return newblock;
 312         }
 313         lock_super(sb);
 314
 315 repeat:
 316         if (goal < 0 || goal >= UDF_SB_PARTLEN(sb, partition))
 317                 goal = 0;
 318
 319         nr_groups = (UDF_SB_PARTLEN(sb, partition) +
 320                 (sizeof(struct SpaceBitmapDesc) << 3) + (sb->s_blocksize * 8) - 1) / (sb->s_blocksize * 8);
 321         block = goal + (sizeof(struct SpaceBitmapDesc) << 3);
 322         block_group = block >> (sb->s_blocksize_bits + 3);
 323         group_start = block_group ? 0 : sizeof(struct SpaceBitmapDesc);
 324
 325         bitmap_nr = load_block_bitmap(sb, block_group);
 326         if (bitmap_nr < 0)
 327                 goto error_return;
 328         bh = UDF_SB_BLOCK_BITMAP(sb, bitmap_nr);
 329         ptr = memscan((char *)bh->b_data + group_start, 0xFF, sb->s_blocksize - group_start);
 330
 331         if ((ptr - ((char *)bh->b_data)) < sb->s_blocksize)
 332         {
 333                 bit = block % (sb->s_blocksize << 3);
 334
 335                 if (udf_test_bit(bit, bh->b_data))
 336                 {
 337                         goto got_block;
 338                 }
 339                 end_goal = (bit + 63) & ~63;
 340                 bit = udf_find_next_one_bit(bh->b_data, end_goal, bit);
 341                 if (bit < end_goal)
 342                         goto got_block;
 343                 ptr = memscan((char *)bh->b_data + (bit >> 3), 0xFF, sb->s_blocksize - ((bit + 7) >> 3));
 344                 newbit = (ptr - ((char *)bh->b_data)) << 3;
 345                 if (newbit < sb->s_blocksize << 3)
 346                 {
 347                         bit = newbit;
 348                         goto search_back;
 349                 }
 350                 newbit = udf_find_next_one_bit(bh->b_data, sb->s_blocksize << 3, bit);
 351                 if (newbit < sb->s_blocksize << 3)
 352                 {
 353                         bit = newbit;
 354                         goto got_block;
 355                 }
 356         }
 357
 358         for (i=0; i<(nr_groups*2); i++)
 359         {
 360                 block_group ++;
 361                 if (block_group >= nr_groups)
 362                         block_group = 0;
 363                 group_start = block_group ? 0 : sizeof(struct SpaceBitmapDesc);
 364
 365                 bitmap_nr = load_block_bitmap(sb, block_group);
 366                 if (bitmap_nr < 0)
 367                         goto error_return;
 368                 bh = UDF_SB_BLOCK_BITMAP(sb, bitmap_nr);
 369                 if (i < nr_groups)
 370                 {
 371                         ptr = memscan((char *)bh->b_data + group_start, 0xFF, sb->s_blocksize - group_start);
 372                         if ((ptr - ((char *)bh->b_data)) < sb->s_blocksize)
 373                         {
 374                                 bit = (ptr - ((char *)bh->b_data)) << 3;
 375                                 break;
 376                         }
 377                 }
 378                 else
 379                 {
 380                         bit = udf_find_next_one_bit((char *)bh->b_data, sb->s_blocksize << 3, group_start << 3);
 381                         if (bit < sb->s_blocksize << 3)
 382                                 break;
 383                 }
 384         }
 385         if (i >= (nr_groups*2))
 386         {
 387                 unlock_super(sb);
 388                 return newblock;
 389         }
 390         if (bit < sb->s_blocksize << 3)
 391                 goto search_back;
 392         else
 393                 bit = udf_find_next_one_bit(bh->b_data, sb->s_blocksize << 3, group_start << 3);
 394         if (bit >= sb->s_blocksize << 3)
 395         {
 396                 unlock_super(sb);
 397                 return 0;
 398         }
 399
 400 search_back:
 401         for (i=0; i<7 && bit > (group_start << 3) && udf_test_bit(bit - 1, bh->b_data); i++, bit--);
 402
 403 got_block:
 404         newblock = bit + (block_group << (sb->s_blocksize_bits + 3)) -
 405                 (sizeof(struct SpaceBitmapDesc) << 3);
 406
 407         tmp = udf_get_pblock(sb, newblock, partition, 0);
 408         if (!udf_clear_bit(bit, bh->b_data))
 409         {
 410                 udf_debug("bit already cleared for block %d\n", bit);
 411                 goto repeat;
 412         }
 413
 414         mark_buffer_dirty(bh, 1);
 415
 416         if (UDF_SB_LVIDBH(sb))
 417         {
 418                 UDF_SB_LVID(sb)->freeSpaceTable[partition] =
 419                         cpu_to_le32(le32_to_cpu(UDF_SB_LVID(sb)->freeSpaceTable[partition])-1);
 420                 mark_buffer_dirty(UDF_SB_LVIDBH(sb), 1);
 421         }
 422         sb->s_dirt = 1;
 423         unlock_super(sb);
 424         *err = 0;
 425         return newblock;
 426
 427 error_return:
 428         *err = -EIO;
 429         unlock_super(sb);
 430         return 0;
 431 }