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         int was_dirty = 0;
 213         int shift;
 214
 215         /* Convert inode block to disk allocation block */
 216         shift = sbi->alloc_blksz_shift - sb->s_blocksize_bits;
 217         ablock = iblock >> sbi->fs_shift;
 218
 219         if (iblock >= hip->fs_blocks) {
 220                 if (iblock > hip->fs_blocks || !create)
 221                         return -EIO;
 222                 if (ablock >= hip->alloc_blocks) {
 223                         res = hfsplus_file_extend(inode);
 224                         if (res)
 225                                 return res;
 226                 }
 227         } else
 228                 create = 0;
 229
 230         if (ablock < hip->first_blocks) {
 231                 dblock = hfsplus_ext_find_block(hip->first_extents, ablock);
 232                 goto done;
 233         }
 234
 235         if (inode->i_ino == HFSPLUS_EXT_CNID)
 236                 return -EIO;
 237
 238         mutex_lock(&hip->extents_lock);
 239
 240         /*
 241          * hfsplus_ext_read_extent will write out a cached extent into
 242          * the extents btree.  In that case we may have to mark the inode
 243          * dirty even for a pure read of an extent here.
 244          */
 245         was_dirty = (hip->extent_state & HFSPLUS_EXT_DIRTY);
 246         res = hfsplus_ext_read_extent(inode, ablock);
 247         if (res) {
 248                 mutex_unlock(&hip->extents_lock);
 249                 return -EIO;
 250         }
 251         dblock = hfsplus_ext_find_block(hip->cached_extents,
 252                                         ablock - hip->cached_start);
 253         mutex_unlock(&hip->extents_lock);
 254
 255 done:
 256         dprint(DBG_EXTENT, "get_block(%lu): %llu - %u\n",
 257                 inode->i_ino, (long long)iblock, dblock);
 258         mask = (1 << sbi->fs_shift) - 1;
 259         map_bh(bh_result, sb,
 260                 (dblock << sbi->fs_shift) + sbi->blockoffset +
 261                         (iblock & mask));
 262         if (create) {
 263                 set_buffer_new(bh_result);
 264                 hip->phys_size += sb->s_blocksize;
 265                 hip->fs_blocks++;
 266                 inode_add_bytes(inode, sb->s_blocksize);
 267         }
 268         if (create || was_dirty)
 269                 mark_inode_dirty(inode);
 270         return 0;
 271 }
 272
 273 static void hfsplus_dump_extent(struct hfsplus_extent *extent)
 274 {
 275         int i;
 276
 277         dprint(DBG_EXTENT, "   ");
 278         for (i = 0; i < 8; i++)
 279                 dprint(DBG_EXTENT, " %u:%u", be32_to_cpu(extent[i].start_block),
 280                                  be32_to_cpu(extent[i].block_count));
 281         dprint(DBG_EXTENT, "\n");
 282 }
 283
 284 static int hfsplus_add_extent(struct hfsplus_extent *extent, u32 offset,
 285                               u32 alloc_block, u32 block_count)
 286 {
 287         u32 count, start;
 288         int i;
 289
 290         hfsplus_dump_extent(extent);
 291         for (i = 0; i < 8; extent++, i++) {
 292                 count = be32_to_cpu(extent->block_count);
 293                 if (offset == count) {
 294                         start = be32_to_cpu(extent->start_block);
 295                         if (alloc_block != start + count) {
 296                                 if (++i >= 8)
 297                                         return -ENOSPC;
 298                                 extent++;
 299                                 extent->start_block = cpu_to_be32(alloc_block);
 300                         } else
 301                                 block_count += count;
 302                         extent->block_count = cpu_to_be32(block_count);
 303                         return 0;
 304                 } else if (offset < count)
 305                         break;
 306                 offset -= count;
 307         }
 308         /* panic? */
 309         return -EIO;
 310 }
 311
 312 static int hfsplus_free_extents(struct super_block *sb,
 313                                 struct hfsplus_extent *extent,
 314                                 u32 offset, u32 block_nr)
 315 {
 316         u32 count, start;
 317         int i;
 318
 319         hfsplus_dump_extent(extent);
 320         for (i = 0; i < 8; extent++, i++) {
 321                 count = be32_to_cpu(extent->block_count);
 322                 if (offset == count)
 323                         goto found;
 324                 else if (offset < count)
 325                         break;
 326                 offset -= count;
 327         }
 328         /* panic? */
 329         return -EIO;
 330 found:
 331         for (;;) {
 332                 start = be32_to_cpu(extent->start_block);
 333                 if (count <= block_nr) {
 334                         hfsplus_block_free(sb, start, count);
 335                         extent->block_count = 0;
 336                         extent->start_block = 0;
 337                         block_nr -= count;
 338                 } else {
 339                         count -= block_nr;
 340                         hfsplus_block_free(sb, start + count, block_nr);
 341                         extent->block_count = cpu_to_be32(count);
 342                         block_nr = 0;
 343                 }
 344                 if (!block_nr || !i)
 345                         return 0;
 346                 i--;
 347                 extent--;
 348                 count = be32_to_cpu(extent->block_count);
 349         }
 350 }
 351
 352 int hfsplus_free_fork(struct super_block *sb, u32 cnid,
 353                 struct hfsplus_fork_raw *fork, int type)
 354 {
 355         struct hfs_find_data fd;
 356         hfsplus_extent_rec ext_entry;
 357         u32 total_blocks, blocks, start;
 358         int res, i;
 359
 360         total_blocks = be32_to_cpu(fork->total_blocks);
 361         if (!total_blocks)
 362                 return 0;
 363
 364         blocks = 0;
 365         for (i = 0; i < 8; i++)
 366                 blocks += be32_to_cpu(fork->extents[i].block_count);
 367
 368         res = hfsplus_free_extents(sb, fork->extents, blocks, blocks);
 369         if (res)
 370                 return res;
 371         if (total_blocks == blocks)
 372                 return 0;
 373
 374         hfs_find_init(HFSPLUS_SB(sb)->ext_tree, &fd);
 375         do {
 376                 res = __hfsplus_ext_read_extent(&fd, ext_entry, cnid,
 377                                                 total_blocks, type);
 378                 if (res)
 379                         break;
 380                 start = be32_to_cpu(fd.key->ext.start_block);
 381                 hfsplus_free_extents(sb, ext_entry,
 382                                      total_blocks - start,
 383                                      total_blocks);
 384                 hfs_brec_remove(&fd);
 385                 total_blocks = start;
 386         } while (total_blocks > blocks);
 387         hfs_find_exit(&fd);
 388
 389         return res;
 390 }
 391
 392 int hfsplus_file_extend(struct inode *inode)
 393 {
 394         struct super_block *sb = inode->i_sb;
 395         struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
 396         struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
 397         u32 start, len, goal;
 398         int res;
 399
 400         if (sbi->total_blocks - sbi->free_blocks + 8 >
 401                         sbi->alloc_file->i_size * 8) {
 402                 /* extend alloc file */
 403                 printk(KERN_ERR "hfs: extend alloc file! "
 404                                 "(%llu,%u,%u)\n",
 405                         sbi->alloc_file->i_size * 8,
 406                         sbi->total_blocks, sbi->free_blocks);
 407                 return -ENOSPC;
 408         }
 409
 410         mutex_lock(&hip->extents_lock);
 411         if (hip->alloc_blocks == hip->first_blocks)
 412                 goal = hfsplus_ext_lastblock(hip->first_extents);
 413         else {
 414                 res = hfsplus_ext_read_extent(inode, hip->alloc_blocks);
 415                 if (res)
 416                         goto out;
 417                 goal = hfsplus_ext_lastblock(hip->cached_extents);
 418         }
 419
 420         len = hip->clump_blocks;
 421         start = hfsplus_block_allocate(sb, sbi->total_blocks, goal, &len);
 422         if (start >= sbi->total_blocks) {
 423                 start = hfsplus_block_allocate(sb, goal, 0, &len);
 424                 if (start >= goal) {
 425                         res = -ENOSPC;
 426                         goto out;
 427                 }
 428         }
 429
 430         dprint(DBG_EXTENT, "extend %lu: %u,%u\n", inode->i_ino, start, len);
 431
 432         if (hip->alloc_blocks <= hip->first_blocks) {
 433                 if (!hip->first_blocks) {
 434                         dprint(DBG_EXTENT, "first extents\n");
 435                         /* no extents yet */
 436                         hip->first_extents[0].start_block = cpu_to_be32(start);
 437                         hip->first_extents[0].block_count = cpu_to_be32(len);
 438                         res = 0;
 439                 } else {
 440                         /* try to append to extents in inode */
 441                         res = hfsplus_add_extent(hip->first_extents,
 442                                                  hip->alloc_blocks,
 443                                                  start, len);
 444                         if (res == -ENOSPC)
 445                                 goto insert_extent;
 446                 }
 447                 if (!res) {
 448                         hfsplus_dump_extent(hip->first_extents);
 449                         hip->first_blocks += len;
 450                 }
 451         } else {
 452                 res = hfsplus_add_extent(hip->cached_extents,
 453                                          hip->alloc_blocks - hip->cached_start,
 454                                          start, len);
 455                 if (!res) {
 456                         hfsplus_dump_extent(hip->cached_extents);
 457                         hip->extent_state |= HFSPLUS_EXT_DIRTY;
 458                         hip->cached_blocks += len;
 459                 } else if (res == -ENOSPC)
 460                         goto insert_extent;
 461         }
 462 out:
 463         mutex_unlock(&hip->extents_lock);
 464         if (!res) {
 465                 hip->alloc_blocks += len;
 466                 hfsplus_mark_inode_dirty(inode, HFSPLUS_I_ALLOC_DIRTY);
 467         }
 468         return res;
 469
 470 insert_extent:
 471         dprint(DBG_EXTENT, "insert new extent\n");
 472         hfsplus_ext_write_extent_locked(inode);
 473
 474         memset(hip->cached_extents, 0, sizeof(hfsplus_extent_rec));
 475         hip->cached_extents[0].start_block = cpu_to_be32(start);
 476         hip->cached_extents[0].block_count = cpu_to_be32(len);
 477         hfsplus_dump_extent(hip->cached_extents);
 478         hip->extent_state |= HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW;
 479         hip->cached_start = hip->alloc_blocks;
 480         hip->cached_blocks = len;
 481
 482         res = 0;
 483         goto out;
 484 }
 485
 486 void hfsplus_file_truncate(struct inode *inode)
 487 {
 488         struct super_block *sb = inode->i_sb;
 489         struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
 490         struct hfs_find_data fd;
 491         u32 alloc_cnt, blk_cnt, start;
 492         int res;
 493
 494         dprint(DBG_INODE, "truncate: %lu, %llu -> %llu\n",
 495                 inode->i_ino, (long long)hip->phys_size,
 496                 inode->i_size);
 497
 498         if (inode->i_size > hip->phys_size) {
 499                 struct address_space *mapping = inode->i_mapping;
 500                 struct page *page;
 501                 void *fsdata;
 502                 u32 size = inode->i_size;
 503                 int res;
 504
 505                 res = pagecache_write_begin(NULL, mapping, size, 0,
 506                                                 AOP_FLAG_UNINTERRUPTIBLE,
 507                                                 &page, &fsdata);
 508                 if (res)
 509                         return;
 510                 res = pagecache_write_end(NULL, mapping, size,
 511                         0, 0, page, fsdata);
 512                 if (res < 0)
 513                         return;
 514                 mark_inode_dirty(inode);
 515                 return;
 516         } else if (inode->i_size == hip->phys_size)
 517                 return;
 518
 519         blk_cnt = (inode->i_size + HFSPLUS_SB(sb)->alloc_blksz - 1) >>
 520                         HFSPLUS_SB(sb)->alloc_blksz_shift;
 521         alloc_cnt = hip->alloc_blocks;
 522         if (blk_cnt == alloc_cnt)
 523                 goto out;
 524
 525         mutex_lock(&hip->extents_lock);
 526         hfs_find_init(HFSPLUS_SB(sb)->ext_tree, &fd);
 527         while (1) {
 528                 if (alloc_cnt == hip->first_blocks) {
 529                         hfsplus_free_extents(sb, hip->first_extents,
 530                                              alloc_cnt, alloc_cnt - blk_cnt);
 531                         hfsplus_dump_extent(hip->first_extents);
 532                         hip->first_blocks = blk_cnt;
 533                         break;
 534                 }
 535                 res = __hfsplus_ext_cache_extent(&fd, inode, alloc_cnt);
 536                 if (res)
 537                         break;
 538                 start = hip->cached_start;
 539                 hfsplus_free_extents(sb, hip->cached_extents,
 540                                      alloc_cnt - start, alloc_cnt - blk_cnt);
 541                 hfsplus_dump_extent(hip->cached_extents);
 542                 if (blk_cnt > start) {
 543                         hip->extent_state |= HFSPLUS_EXT_DIRTY;
 544                         break;
 545                 }
 546                 alloc_cnt = start;
 547                 hip->cached_start = hip->cached_blocks = 0;
 548                 hip->extent_state &= ~(HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW);
 549                 hfs_brec_remove(&fd);
 550         }
 551         hfs_find_exit(&fd);
 552         mutex_unlock(&hip->extents_lock);
 553
 554         hip->alloc_blocks = blk_cnt;
 555 out:
 556         hip->phys_size = inode->i_size;
 557         hip->fs_blocks = (inode->i_size + sb->s_blocksize - 1) >>
 558                 sb->s_blocksize_bits;
 559         inode_set_bytes(inode, hip->fs_blocks << sb->s_blocksize_bits);
 560         hfsplus_mark_inode_dirty(inode, HFSPLUS_I_ALLOC_DIRTY);
 561 }