fs/hfsplus/extents.c

   1 /*
   2  *  linux/fs/hfsplus/extents.c
   3  *
   4  * Copyright (C) 2001
   5  * Brad Boyer (flar@allandria.com)
   6  * (C) 2003 Ardis Technologies <roman@ardistech.com>
   7  *
   8  * Handling of Extents both in catalog and extents overflow trees
   9  */
  10
  11 #include <linux/errno.h>
  12 #include <linux/fs.h>
  13 #include <linux/pagemap.h>
  14
  15 #include "hfsplus_fs.h"
  16 #include "hfsplus_raw.h"
  17
  18 /* Compare two extents keys, returns 0 on same, pos/neg for difference */
  19 int hfsplus_ext_cmp_key(const hfsplus_btree_key *k1,
  20                         const hfsplus_btree_key *k2)
  21 {
  22         __be32 k1id, k2id;
  23         __be32 k1s, k2s;
  24
  25         k1id = k1->ext.cnid;
  26         k2id = k2->ext.cnid;
  27         if (k1id != k2id)
  28                 return be32_to_cpu(k1id) < be32_to_cpu(k2id) ? -1 : 1;
  29
  30         if (k1->ext.fork_type != k2->ext.fork_type)
  31                 return k1->ext.fork_type < k2->ext.fork_type ? -1 : 1;
  32
  33         k1s = k1->ext.start_block;
  34         k2s = k2->ext.start_block;
  35         if (k1s == k2s)
  36                 return 0;
  37         return be32_to_cpu(k1s) < be32_to_cpu(k2s) ? -1 : 1;
  38 }
  39
  40 static void hfsplus_ext_build_key(hfsplus_btree_key *key, u32 cnid,
  41                                   u32 block, u8 type)
  42 {
  43         key->key_len = cpu_to_be16(HFSPLUS_EXT_KEYLEN - 2);
  44         key->ext.cnid = cpu_to_be32(cnid);
  45         key->ext.start_block = cpu_to_be32(block);
  46         key->ext.fork_type = type;
  47         key->ext.pad = 0;
  48 }
  49
  50 static u32 hfsplus_ext_find_block(struct hfsplus_extent *ext, u32 off)
  51 {
  52         int i;
  53         u32 count;
  54
  55         for (i = 0; i < 8; ext++, i++) {
  56                 count = be32_to_cpu(ext->block_count);
  57                 if (off < count)
  58                         return be32_to_cpu(ext->start_block) + off;
  59                 off -= count;
  60         }
  61         /* panic? */
  62         return 0;
  63 }
  64
  65 static int hfsplus_ext_block_count(struct hfsplus_extent *ext)
  66 {
  67         int i;
  68         u32 count = 0;
  69
  70         for (i = 0; i < 8; ext++, i++)
  71                 count += be32_to_cpu(ext->block_count);
  72         return count;
  73 }
  74
  75 static u32 hfsplus_ext_lastblock(struct hfsplus_extent *ext)
  76 {
  77         int i;
  78
  79         ext += 7;
  80         for (i = 0; i < 7; ext--, i++)
  81                 if (ext->block_count)
  82                         break;
  83         return be32_to_cpu(ext->start_block) + be32_to_cpu(ext->block_count);
  84 }
  85
  86 static void __hfsplus_ext_write_extent(struct inode *inode,
  87                 struct hfs_find_data *fd)
  88 {
  89         struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
  90         int res;
  91
  92         WARN_ON(!mutex_is_locked(&hip->extents_lock));
  93
  94         hfsplus_ext_build_key(fd->search_key, inode->i_ino, hip->cached_start,
  95                               HFSPLUS_IS_RSRC(inode) ?
  96                                 HFSPLUS_TYPE_RSRC : HFSPLUS_TYPE_DATA);
  97
  98         res = hfs_brec_find(fd);
  99         if (hip->extent_state & HFSPLUS_EXT_NEW) {
 100                 if (res != -ENOENT)
 101                         return;
 102                 hfs_brec_insert(fd, hip->cached_extents,
 103                                 sizeof(hfsplus_extent_rec));
 104                 hip->extent_state &= ~(HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW);
 105         } else {
 106                 if (res)
 107                         return;
 108                 hfs_bnode_write(fd->bnode, hip->cached_extents,
 109                                 fd->entryoffset, fd->entrylength);
 110                 hip->extent_state &= ~HFSPLUS_EXT_DIRTY;
 111         }
 112
 113         /*
 114          * We can't just use hfsplus_mark_inode_dirty here, because we
 115          * also get called from hfsplus_write_inode, which should not
 116          * redirty the inode.  Instead the callers have to be careful
 117          * to explicily mark the inode dirty, too.
 118          */
 119         set_bit(HFSPLUS_I_EXT_DIRTY, &hip->flags);
 120 }
 121
 122 static void hfsplus_ext_write_extent_locked(struct inode *inode)
 123 {
 124         if (HFSPLUS_I(inode)->extent_state & HFSPLUS_EXT_DIRTY) {
 125                 struct hfs_find_data fd;
 126
 127                 hfs_find_init(HFSPLUS_SB(inode->i_sb)->ext_tree, &fd);
 128                 __hfsplus_ext_write_extent(inode, &fd);
 129                 hfs_find_exit(&fd);
 130         }
 131 }
 132
 133 void hfsplus_ext_write_extent(struct inode *inode)
 134 {
 135         mutex_lock(&HFSPLUS_I(inode)->extents_lock);
 136         hfsplus_ext_write_extent_locked(inode);
 137         mutex_unlock(&HFSPLUS_I(inode)->extents_lock);
 138 }
 139
 140 static inline int __hfsplus_ext_read_extent(struct hfs_find_data *fd,
 141                                             struct hfsplus_extent *extent,
 142                                             u32 cnid, u32 block, u8 type)
 143 {
 144         int res;
 145
 146         hfsplus_ext_build_key(fd->search_key, cnid, block, type);
 147         fd->key->ext.cnid = 0;
 148         res = hfs_brec_find(fd);
 149         if (res && res != -ENOENT)
 150                 return res;
 151         if (fd->key->ext.cnid != fd->search_key->ext.cnid ||
 152             fd->key->ext.fork_type != fd->search_key->ext.fork_type)
 153                 return -ENOENT;
 154         if (fd->entrylength != sizeof(hfsplus_extent_rec))
 155                 return -EIO;
 156         hfs_bnode_read(fd->bnode, extent, fd->entryoffset,
 157                 sizeof(hfsplus_extent_rec));
 158         return 0;
 159 }
 160
 161 static inline int __hfsplus_ext_cache_extent(struct hfs_find_data *fd,
 162                 struct inode *inode, u32 block)
 163 {
 164         struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
 165         int res;
 166
 167         WARN_ON(!mutex_is_locked(&hip->extents_lock));
 168
 169         if (hip->extent_state & HFSPLUS_EXT_DIRTY)
 170                 __hfsplus_ext_write_extent(inode, fd);
 171
 172         res = __hfsplus_ext_read_extent(fd, hip->cached_extents, inode->i_ino,
 173                                         block, HFSPLUS_IS_RSRC(inode) ?
 174                                                 HFSPLUS_TYPE_RSRC :
 175                                                 HFSPLUS_TYPE_DATA);
 176         if (!res) {
 177                 hip->cached_start = be32_to_cpu(fd->key->ext.start_block);
 178                 hip->cached_blocks =
 179                         hfsplus_ext_block_count(hip->cached_extents);
 180         } else {
 181                 hip->cached_start = hip->cached_blocks = 0;
 182                 hip->extent_state &= ~(HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW);
 183         }
 184         return res;
 185 }
 186
 187 static int hfsplus_ext_read_extent(struct inode *inode, u32 block)
 188 {
 189         struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
 190         struct hfs_find_data fd;
 191         int res;
 192
 193         if (block >= hip->cached_start &&
 194             block < hip->cached_start + hip->cached_blocks)
 195                 return 0;
 196
 197         hfs_find_init(HFSPLUS_SB(inode->i_sb)->ext_tree, &fd);
 198         res = __hfsplus_ext_cache_extent(&fd, inode, block);
 199         hfs_find_exit(&fd);
 200         return res;
 201 }
 202
 203 /* Get a block at iblock for inode, possibly allocating if create */
 204 int hfsplus_get_block(struct inode *inode, sector_t iblock,
 205                       struct buffer_head *bh_result, int create)
 206 {
 207         struct super_block *sb = inode->i_sb;
 208         struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
 209         struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
 210         int res = -EIO;
 211         u32 ablock, dblock, mask;
 212         sector_t sector;
 213         int was_dirty = 0;
 214         int shift;
 215
 216         /* Convert inode block to disk allocation block */
 217         shift = sbi->alloc_blksz_shift - sb->s_blocksize_bits;
 218         ablock = iblock >> sbi->fs_shift;
 219
 220         if (iblock >= hip->fs_blocks) {
 221                 if (iblock > hip->fs_blocks || !create)
 222                         return -EIO;
 223                 if (ablock >= hip->alloc_blocks) {
 224                         res = hfsplus_file_extend(inode);
 225                         if (res)
 226                                 return res;
 227                 }
 228         } else
 229                 create = 0;
 230
 231         if (ablock < hip->first_blocks) {
 232                 dblock = hfsplus_ext_find_block(hip->first_extents, ablock);
 233                 goto done;
 234         }
 235
 236         if (inode->i_ino == HFSPLUS_EXT_CNID)
 237                 return -EIO;
 238
 239         mutex_lock(&hip->extents_lock);
 240
 241         /*
 242          * hfsplus_ext_read_extent will write out a cached extent into
 243          * the extents btree.  In that case we may have to mark the inode
 244          * dirty even for a pure read of an extent here.
 245          */
 246         was_dirty = (hip->extent_state & HFSPLUS_EXT_DIRTY);
 247         res = hfsplus_ext_read_extent(inode, ablock);
 248         if (res) {
 249                 mutex_unlock(&hip->extents_lock);
 250                 return -EIO;
 251         }
 252         dblock = hfsplus_ext_find_block(hip->cached_extents,
 253                                         ablock - hip->cached_start);
 254         mutex_unlock(&hip->extents_lock);
 255
 256 done:
 257         dprint(DBG_EXTENT, "get_block(%lu): %llu - %u\n",
 258                 inode->i_ino, (long long)iblock, dblock);
 259
 260         mask = (1 << sbi->fs_shift) - 1;
 261         sector = ((sector_t)dblock << sbi->fs_shift) +
 262                   sbi->blockoffset + (iblock & mask);
 263         map_bh(bh_result, sb, sector);
 264
 265         if (create) {
 266                 set_buffer_new(bh_result);
 267                 hip->phys_size += sb->s_blocksize;
 268                 hip->fs_blocks++;
 269                 inode_add_bytes(inode, sb->s_blocksize);
 270         }
 271         if (create || was_dirty)
 272                 mark_inode_dirty(inode);
 273         return 0;
 274 }
 275
 276 static void hfsplus_dump_extent(struct hfsplus_extent *extent)
 277 {
 278         int i;
 279
 280         dprint(DBG_EXTENT, "   ");
 281         for (i = 0; i < 8; i++)
 282                 dprint(DBG_EXTENT, " %u:%u", be32_to_cpu(extent[i].start_block),
 283                                  be32_to_cpu(extent[i].block_count));
 284         dprint(DBG_EXTENT, "\n");
 285 }
 286
 287 static int hfsplus_add_extent(struct hfsplus_extent *extent, u32 offset,
 288                               u32 alloc_block, u32 block_count)
 289 {
 290         u32 count, start;
 291         int i;
 292
 293         hfsplus_dump_extent(extent);
 294         for (i = 0; i < 8; extent++, i++) {
 295                 count = be32_to_cpu(extent->block_count);
 296                 if (offset == count) {
 297                         start = be32_to_cpu(extent->start_block);
 298                         if (alloc_block != start + count) {
 299                                 if (++i >= 8)
 300                                         return -ENOSPC;
 301                                 extent++;
 302                                 extent->start_block = cpu_to_be32(alloc_block);
 303                         } else
 304                                 block_count += count;
 305                         extent->block_count = cpu_to_be32(block_count);
 306                         return 0;
 307                 } else if (offset < count)
 308                         break;
 309                 offset -= count;
 310         }
 311         /* panic? */
 312         return -EIO;
 313 }
 314
 315 static int hfsplus_free_extents(struct super_block *sb,
 316                                 struct hfsplus_extent *extent,
 317                                 u32 offset, u32 block_nr)
 318 {
 319         u32 count, start;
 320         int i;
 321
 322         hfsplus_dump_extent(extent);
 323         for (i = 0; i < 8; extent++, i++) {
 324                 count = be32_to_cpu(extent->block_count);
 325                 if (offset == count)
 326                         goto found;
 327                 else if (offset < count)
 328                         break;
 329                 offset -= count;
 330         }
 331         /* panic? */
 332         return -EIO;
 333 found:
 334         for (;;) {
 335                 start = be32_to_cpu(extent->start_block);
 336                 if (count <= block_nr) {
 337                         hfsplus_block_free(sb, start, count);
 338                         extent->block_count = 0;
 339                         extent->start_block = 0;
 340                         block_nr -= count;
 341                 } else {
 342                         count -= block_nr;
 343                         hfsplus_block_free(sb, start + count, block_nr);
 344                         extent->block_count = cpu_to_be32(count);
 345                         block_nr = 0;
 346                 }
 347                 if (!block_nr || !i)
 348                         return 0;
 349                 i--;
 350                 extent--;
 351                 count = be32_to_cpu(extent->block_count);
 352         }
 353 }
 354
 355 int hfsplus_free_fork(struct super_block *sb, u32 cnid,
 356                 struct hfsplus_fork_raw *fork, int type)
 357 {
 358         struct hfs_find_data fd;
 359         hfsplus_extent_rec ext_entry;
 360         u32 total_blocks, blocks, start;
 361         int res, i;
 362
 363         total_blocks = be32_to_cpu(fork->total_blocks);
 364         if (!total_blocks)
 365                 return 0;
 366
 367         blocks = 0;
 368         for (i = 0; i < 8; i++)
 369                 blocks += be32_to_cpu(fork->extents[i].block_count);
 370
 371         res = hfsplus_free_extents(sb, fork->extents, blocks, blocks);
 372         if (res)
 373                 return res;
 374         if (total_blocks == blocks)
 375                 return 0;
 376
 377         hfs_find_init(HFSPLUS_SB(sb)->ext_tree, &fd);
 378         do {
 379                 res = __hfsplus_ext_read_extent(&fd, ext_entry, cnid,
 380                                                 total_blocks, type);
 381                 if (res)
 382                         break;
 383                 start = be32_to_cpu(fd.key->ext.start_block);
 384                 hfsplus_free_extents(sb, ext_entry,
 385                                      total_blocks - start,
 386                                      total_blocks);
 387                 hfs_brec_remove(&fd);
 388                 total_blocks = start;
 389         } while (total_blocks > blocks);
 390         hfs_find_exit(&fd);
 391
 392         return res;
 393 }
 394
 395 int hfsplus_file_extend(struct inode *inode)
 396 {
 397         struct super_block *sb = inode->i_sb;
 398         struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
 399         struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
 400         u32 start, len, goal;
 401         int res;
 402
 403         if (sbi->alloc_file->i_size * 8 <
 404             sbi->total_blocks - sbi->free_blocks + 8) {
 405                 /* extend alloc file */
 406                 printk(KERN_ERR "hfs: extend alloc file! "
 407                                 "(%llu,%u,%u)\n",
 408                         sbi->alloc_file->i_size * 8,
 409                         sbi->total_blocks, sbi->free_blocks);
 410                 return -ENOSPC;
 411         }
 412
 413         mutex_lock(&hip->extents_lock);
 414         if (hip->alloc_blocks == hip->first_blocks)
 415                 goal = hfsplus_ext_lastblock(hip->first_extents);
 416         else {
 417                 res = hfsplus_ext_read_extent(inode, hip->alloc_blocks);
 418                 if (res)
 419                         goto out;
 420                 goal = hfsplus_ext_lastblock(hip->cached_extents);
 421         }
 422
 423         len = hip->clump_blocks;
 424         start = hfsplus_block_allocate(sb, sbi->total_blocks, goal, &len);
 425         if (start >= sbi->total_blocks) {
 426                 start = hfsplus_block_allocate(sb, goal, 0, &len);
 427                 if (start >= goal) {
 428                         res = -ENOSPC;
 429                         goto out;
 430                 }
 431         }
 432
 433         dprint(DBG_EXTENT, "extend %lu: %u,%u\n", inode->i_ino, start, len);
 434
 435         if (hip->alloc_blocks <= hip->first_blocks) {
 436                 if (!hip->first_blocks) {
 437                         dprint(DBG_EXTENT, "first extents\n");
 438                         /* no extents yet */
 439                         hip->first_extents[0].start_block = cpu_to_be32(start);
 440                         hip->first_extents[0].block_count = cpu_to_be32(len);
 441                         res = 0;
 442                 } else {
 443                         /* try to append to extents in inode */
 444                         res = hfsplus_add_extent(hip->first_extents,
 445                                                  hip->alloc_blocks,
 446                                                  start, len);
 447                         if (res == -ENOSPC)
 448                                 goto insert_extent;
 449                 }
 450                 if (!res) {
 451                         hfsplus_dump_extent(hip->first_extents);
 452                         hip->first_blocks += len;
 453                 }
 454         } else {
 455                 res = hfsplus_add_extent(hip->cached_extents,
 456                                          hip->alloc_blocks - hip->cached_start,
 457                                          start, len);
 458                 if (!res) {
 459                         hfsplus_dump_extent(hip->cached_extents);
 460                         hip->extent_state |= HFSPLUS_EXT_DIRTY;
 461                         hip->cached_blocks += len;
 462                 } else if (res == -ENOSPC)
 463                         goto insert_extent;
 464         }
 465 out:
 466         mutex_unlock(&hip->extents_lock);
 467         if (!res) {
 468                 hip->alloc_blocks += len;
 469                 hfsplus_mark_inode_dirty(inode, HFSPLUS_I_ALLOC_DIRTY);
 470         }
 471         return res;
 472
 473 insert_extent:
 474         dprint(DBG_EXTENT, "insert new extent\n");
 475         hfsplus_ext_write_extent_locked(inode);
 476
 477         memset(hip->cached_extents, 0, sizeof(hfsplus_extent_rec));
 478         hip->cached_extents[0].start_block = cpu_to_be32(start);
 479         hip->cached_extents[0].block_count = cpu_to_be32(len);
 480         hfsplus_dump_extent(hip->cached_extents);
 481         hip->extent_state |= HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW;
 482         hip->cached_start = hip->alloc_blocks;
 483         hip->cached_blocks = len;
 484
 485         res = 0;
 486         goto out;
 487 }
 488
 489 void hfsplus_file_truncate(struct inode *inode)
 490 {
 491         struct super_block *sb = inode->i_sb;
 492         struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
 493         struct hfs_find_data fd;
 494         u32 alloc_cnt, blk_cnt, start;
 495         int res;
 496
 497         dprint(DBG_INODE, "truncate: %lu, %llu -> %llu\n",
 498                 inode->i_ino, (long long)hip->phys_size,
 499                 inode->i_size);
 500
 501         if (inode->i_size > hip->phys_size) {
 502                 struct address_space *mapping = inode->i_mapping;
 503                 struct page *page;
 504                 void *fsdata;
 505                 u32 size = inode->i_size;
 506                 int res;
 507
 508                 res = pagecache_write_begin(NULL, mapping, size, 0,
 509                                                 AOP_FLAG_UNINTERRUPTIBLE,
 510                                                 &page, &fsdata);
 511                 if (res)
 512                         return;
 513                 res = pagecache_write_end(NULL, mapping, size,
 514                         0, 0, page, fsdata);
 515                 if (res < 0)
 516                         return;
 517                 mark_inode_dirty(inode);
 518                 return;
 519         } else if (inode->i_size == hip->phys_size)
 520                 return;
 521
 522         blk_cnt = (inode->i_size + HFSPLUS_SB(sb)->alloc_blksz - 1) >>
 523                         HFSPLUS_SB(sb)->alloc_blksz_shift;
 524         alloc_cnt = hip->alloc_blocks;
 525         if (blk_cnt == alloc_cnt)
 526                 goto out;
 527
 528         mutex_lock(&hip->extents_lock);
 529         hfs_find_init(HFSPLUS_SB(sb)->ext_tree, &fd);
 530         while (1) {
 531                 if (alloc_cnt == hip->first_blocks) {
 532                         hfsplus_free_extents(sb, hip->first_extents,
 533                                              alloc_cnt, alloc_cnt - blk_cnt);
 534                         hfsplus_dump_extent(hip->first_extents);
 535                         hip->first_blocks = blk_cnt;
 536                         break;
 537                 }
 538                 res = __hfsplus_ext_cache_extent(&fd, inode, alloc_cnt);
 539                 if (res)
 540                         break;
 541                 start = hip->cached_start;
 542                 hfsplus_free_extents(sb, hip->cached_extents,
 543                                      alloc_cnt - start, alloc_cnt - blk_cnt);
 544                 hfsplus_dump_extent(hip->cached_extents);
 545                 if (blk_cnt > start) {
 546                         hip->extent_state |= HFSPLUS_EXT_DIRTY;
 547                         break;
 548                 }
 549                 alloc_cnt = start;
 550                 hip->cached_start = hip->cached_blocks = 0;
 551                 hip->extent_state &= ~(HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW);
 552                 hfs_brec_remove(&fd);
 553         }
 554         hfs_find_exit(&fd);
 555         mutex_unlock(&hip->extents_lock);
 556
 557         hip->alloc_blocks = blk_cnt;
 558 out:
 559         hip->phys_size = inode->i_size;
 560         hip->fs_blocks = (inode->i_size + sb->s_blocksize - 1) >>
 561                 sb->s_blocksize_bits;
 562         inode_set_bytes(inode, hip->fs_blocks << sb->s_blocksize_bits);
 563         hfsplus_mark_inode_dirty(inode, HFSPLUS_I_ALLOC_DIRTY);
 564 }