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 int hfsplus_ext_write_extent_locked(struct inode *inode)
 123 {
 124         int res;
 125
 126         if (HFSPLUS_I(inode)->extent_state & HFSPLUS_EXT_DIRTY) {
 127                 struct hfs_find_data fd;
 128
 129                 res = hfs_find_init(HFSPLUS_SB(inode->i_sb)->ext_tree, &fd);
 130                 if (res)
 131                         return res;
 132                 __hfsplus_ext_write_extent(inode, &fd);
 133                 hfs_find_exit(&fd);
 134         }
 135         return 0;
 136 }
 137
 138 int hfsplus_ext_write_extent(struct inode *inode)
 139 {
 140         int res;
 141
 142         mutex_lock(&HFSPLUS_I(inode)->extents_lock);
 143         res = hfsplus_ext_write_extent_locked(inode);
 144         mutex_unlock(&HFSPLUS_I(inode)->extents_lock);
 145
 146         return res;
 147 }
 148
 149 static inline int __hfsplus_ext_read_extent(struct hfs_find_data *fd,
 150                                             struct hfsplus_extent *extent,
 151                                             u32 cnid, u32 block, u8 type)
 152 {
 153         int res;
 154
 155         hfsplus_ext_build_key(fd->search_key, cnid, block, type);
 156         fd->key->ext.cnid = 0;
 157         res = hfs_brec_find(fd);
 158         if (res && res != -ENOENT)
 159                 return res;
 160         if (fd->key->ext.cnid != fd->search_key->ext.cnid ||
 161             fd->key->ext.fork_type != fd->search_key->ext.fork_type)
 162                 return -ENOENT;
 163         if (fd->entrylength != sizeof(hfsplus_extent_rec))
 164                 return -EIO;
 165         hfs_bnode_read(fd->bnode, extent, fd->entryoffset,
 166                 sizeof(hfsplus_extent_rec));
 167         return 0;
 168 }
 169
 170 static inline int __hfsplus_ext_cache_extent(struct hfs_find_data *fd,
 171                 struct inode *inode, u32 block)
 172 {
 173         struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
 174         int res;
 175
 176         WARN_ON(!mutex_is_locked(&hip->extents_lock));
 177
 178         if (hip->extent_state & HFSPLUS_EXT_DIRTY)
 179                 __hfsplus_ext_write_extent(inode, fd);
 180
 181         res = __hfsplus_ext_read_extent(fd, hip->cached_extents, inode->i_ino,
 182                                         block, HFSPLUS_IS_RSRC(inode) ?
 183                                                 HFSPLUS_TYPE_RSRC :
 184                                                 HFSPLUS_TYPE_DATA);
 185         if (!res) {
 186                 hip->cached_start = be32_to_cpu(fd->key->ext.start_block);
 187                 hip->cached_blocks =
 188                         hfsplus_ext_block_count(hip->cached_extents);
 189         } else {
 190                 hip->cached_start = hip->cached_blocks = 0;
 191                 hip->extent_state &= ~(HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW);
 192         }
 193         return res;
 194 }
 195
 196 static int hfsplus_ext_read_extent(struct inode *inode, u32 block)
 197 {
 198         struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
 199         struct hfs_find_data fd;
 200         int res;
 201
 202         if (block >= hip->cached_start &&
 203             block < hip->cached_start + hip->cached_blocks)
 204                 return 0;
 205
 206         res = hfs_find_init(HFSPLUS_SB(inode->i_sb)->ext_tree, &fd);
 207         if (!res) {
 208                 res = __hfsplus_ext_cache_extent(&fd, inode, block);
 209                 hfs_find_exit(&fd);
 210         }
 211         return res;
 212 }
 213
 214 /* Get a block at iblock for inode, possibly allocating if create */
 215 int hfsplus_get_block(struct inode *inode, sector_t iblock,
 216                       struct buffer_head *bh_result, int create)
 217 {
 218         struct super_block *sb = inode->i_sb;
 219         struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
 220         struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
 221         int res = -EIO;
 222         u32 ablock, dblock, mask;
 223         sector_t sector;
 224         int was_dirty = 0;
 225         int shift;
 226
 227         /* Convert inode block to disk allocation block */
 228         shift = sbi->alloc_blksz_shift - sb->s_blocksize_bits;
 229         ablock = iblock >> sbi->fs_shift;
 230
 231         if (iblock >= hip->fs_blocks) {
 232                 if (iblock > hip->fs_blocks || !create)
 233                         return -EIO;
 234                 if (ablock >= hip->alloc_blocks) {
 235                         res = hfsplus_file_extend(inode);
 236                         if (res)
 237                                 return res;
 238                 }
 239         } else
 240                 create = 0;
 241
 242         if (ablock < hip->first_blocks) {
 243                 dblock = hfsplus_ext_find_block(hip->first_extents, ablock);
 244                 goto done;
 245         }
 246
 247         if (inode->i_ino == HFSPLUS_EXT_CNID)
 248                 return -EIO;
 249
 250         mutex_lock(&hip->extents_lock);
 251
 252         /*
 253          * hfsplus_ext_read_extent will write out a cached extent into
 254          * the extents btree.  In that case we may have to mark the inode
 255          * dirty even for a pure read of an extent here.
 256          */
 257         was_dirty = (hip->extent_state & HFSPLUS_EXT_DIRTY);
 258         res = hfsplus_ext_read_extent(inode, ablock);
 259         if (res) {
 260                 mutex_unlock(&hip->extents_lock);
 261                 return -EIO;
 262         }
 263         dblock = hfsplus_ext_find_block(hip->cached_extents,
 264                                         ablock - hip->cached_start);
 265         mutex_unlock(&hip->extents_lock);
 266
 267 done:
 268         dprint(DBG_EXTENT, "get_block(%lu): %llu - %u\n",
 269                 inode->i_ino, (long long)iblock, dblock);
 270
 271         mask = (1 << sbi->fs_shift) - 1;
 272         sector = ((sector_t)dblock << sbi->fs_shift) +
 273                   sbi->blockoffset + (iblock & mask);
 274         map_bh(bh_result, sb, sector);
 275
 276         if (create) {
 277                 set_buffer_new(bh_result);
 278                 hip->phys_size += sb->s_blocksize;
 279                 hip->fs_blocks++;
 280                 inode_add_bytes(inode, sb->s_blocksize);
 281         }
 282         if (create || was_dirty)
 283                 mark_inode_dirty(inode);
 284         return 0;
 285 }
 286
 287 static void hfsplus_dump_extent(struct hfsplus_extent *extent)
 288 {
 289         int i;
 290
 291         dprint(DBG_EXTENT, "   ");
 292         for (i = 0; i < 8; i++)
 293                 dprint(DBG_EXTENT, " %u:%u", be32_to_cpu(extent[i].start_block),
 294                                  be32_to_cpu(extent[i].block_count));
 295         dprint(DBG_EXTENT, "\n");
 296 }
 297
 298 static int hfsplus_add_extent(struct hfsplus_extent *extent, u32 offset,
 299                               u32 alloc_block, u32 block_count)
 300 {
 301         u32 count, start;
 302         int i;
 303
 304         hfsplus_dump_extent(extent);
 305         for (i = 0; i < 8; extent++, i++) {
 306                 count = be32_to_cpu(extent->block_count);
 307                 if (offset == count) {
 308                         start = be32_to_cpu(extent->start_block);
 309                         if (alloc_block != start + count) {
 310                                 if (++i >= 8)
 311                                         return -ENOSPC;
 312                                 extent++;
 313                                 extent->start_block = cpu_to_be32(alloc_block);
 314                         } else
 315                                 block_count += count;
 316                         extent->block_count = cpu_to_be32(block_count);
 317                         return 0;
 318                 } else if (offset < count)
 319                         break;
 320                 offset -= count;
 321         }
 322         /* panic? */
 323         return -EIO;
 324 }
 325
 326 static int hfsplus_free_extents(struct super_block *sb,
 327                                 struct hfsplus_extent *extent,
 328                                 u32 offset, u32 block_nr)
 329 {
 330         u32 count, start;
 331         int i;
 332
 333         hfsplus_dump_extent(extent);
 334         for (i = 0; i < 8; extent++, i++) {
 335                 count = be32_to_cpu(extent->block_count);
 336                 if (offset == count)
 337                         goto found;
 338                 else if (offset < count)
 339                         break;
 340                 offset -= count;
 341         }
 342         /* panic? */
 343         return -EIO;
 344 found:
 345         for (;;) {
 346                 start = be32_to_cpu(extent->start_block);
 347                 if (count <= block_nr) {
 348                         hfsplus_block_free(sb, start, count);
 349                         extent->block_count = 0;
 350                         extent->start_block = 0;
 351                         block_nr -= count;
 352                 } else {
 353                         count -= block_nr;
 354                         hfsplus_block_free(sb, start + count, block_nr);
 355                         extent->block_count = cpu_to_be32(count);
 356                         block_nr = 0;
 357                 }
 358                 if (!block_nr || !i)
 359                         return 0;
 360                 i--;
 361                 extent--;
 362                 count = be32_to_cpu(extent->block_count);
 363         }
 364 }
 365
 366 int hfsplus_free_fork(struct super_block *sb, u32 cnid,
 367                 struct hfsplus_fork_raw *fork, int type)
 368 {
 369         struct hfs_find_data fd;
 370         hfsplus_extent_rec ext_entry;
 371         u32 total_blocks, blocks, start;
 372         int res, i;
 373
 374         total_blocks = be32_to_cpu(fork->total_blocks);
 375         if (!total_blocks)
 376                 return 0;
 377
 378         blocks = 0;
 379         for (i = 0; i < 8; i++)
 380                 blocks += be32_to_cpu(fork->extents[i].block_count);
 381
 382         res = hfsplus_free_extents(sb, fork->extents, blocks, blocks);
 383         if (res)
 384                 return res;
 385         if (total_blocks == blocks)
 386                 return 0;
 387
 388         res = hfs_find_init(HFSPLUS_SB(sb)->ext_tree, &fd);
 389         if (res)
 390                 return res;
 391         do {
 392                 res = __hfsplus_ext_read_extent(&fd, ext_entry, cnid,
 393                                                 total_blocks, type);
 394                 if (res)
 395                         break;
 396                 start = be32_to_cpu(fd.key->ext.start_block);
 397                 hfsplus_free_extents(sb, ext_entry,
 398                                      total_blocks - start,
 399                                      total_blocks);
 400                 hfs_brec_remove(&fd);
 401                 total_blocks = start;
 402         } while (total_blocks > blocks);
 403         hfs_find_exit(&fd);
 404
 405         return res;
 406 }
 407
 408 int hfsplus_file_extend(struct inode *inode)
 409 {
 410         struct super_block *sb = inode->i_sb;
 411         struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
 412         struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
 413         u32 start, len, goal;
 414         int res;
 415
 416         if (sbi->alloc_file->i_size * 8 <
 417             sbi->total_blocks - sbi->free_blocks + 8) {
 418                 /* extend alloc file */
 419                 printk(KERN_ERR "hfs: extend alloc file! "
 420                                 "(%llu,%u,%u)\n",
 421                         sbi->alloc_file->i_size * 8,
 422                         sbi->total_blocks, sbi->free_blocks);
 423                 return -ENOSPC;
 424         }
 425
 426         mutex_lock(&hip->extents_lock);
 427         if (hip->alloc_blocks == hip->first_blocks)
 428                 goal = hfsplus_ext_lastblock(hip->first_extents);
 429         else {
 430                 res = hfsplus_ext_read_extent(inode, hip->alloc_blocks);
 431                 if (res)
 432                         goto out;
 433                 goal = hfsplus_ext_lastblock(hip->cached_extents);
 434         }
 435
 436         len = hip->clump_blocks;
 437         start = hfsplus_block_allocate(sb, sbi->total_blocks, goal, &len);
 438         if (start >= sbi->total_blocks) {
 439                 start = hfsplus_block_allocate(sb, goal, 0, &len);
 440                 if (start >= goal) {
 441                         res = -ENOSPC;
 442                         goto out;
 443                 }
 444         }
 445
 446         dprint(DBG_EXTENT, "extend %lu: %u,%u\n", inode->i_ino, start, len);
 447
 448         if (hip->alloc_blocks <= hip->first_blocks) {
 449                 if (!hip->first_blocks) {
 450                         dprint(DBG_EXTENT, "first extents\n");
 451                         /* no extents yet */
 452                         hip->first_extents[0].start_block = cpu_to_be32(start);
 453                         hip->first_extents[0].block_count = cpu_to_be32(len);
 454                         res = 0;
 455                 } else {
 456                         /* try to append to extents in inode */
 457                         res = hfsplus_add_extent(hip->first_extents,
 458                                                  hip->alloc_blocks,
 459                                                  start, len);
 460                         if (res == -ENOSPC)
 461                                 goto insert_extent;
 462                 }
 463                 if (!res) {
 464                         hfsplus_dump_extent(hip->first_extents);
 465                         hip->first_blocks += len;
 466                 }
 467         } else {
 468                 res = hfsplus_add_extent(hip->cached_extents,
 469                                          hip->alloc_blocks - hip->cached_start,
 470                                          start, len);
 471                 if (!res) {
 472                         hfsplus_dump_extent(hip->cached_extents);
 473                         hip->extent_state |= HFSPLUS_EXT_DIRTY;
 474                         hip->cached_blocks += len;
 475                 } else if (res == -ENOSPC)
 476                         goto insert_extent;
 477         }
 478 out:
 479         mutex_unlock(&hip->extents_lock);
 480         if (!res) {
 481                 hip->alloc_blocks += len;
 482                 hfsplus_mark_inode_dirty(inode, HFSPLUS_I_ALLOC_DIRTY);
 483         }
 484         return res;
 485
 486 insert_extent:
 487         dprint(DBG_EXTENT, "insert new extent\n");
 488         res = hfsplus_ext_write_extent_locked(inode);
 489         if (res)
 490                 goto out;
 491
 492         memset(hip->cached_extents, 0, sizeof(hfsplus_extent_rec));
 493         hip->cached_extents[0].start_block = cpu_to_be32(start);
 494         hip->cached_extents[0].block_count = cpu_to_be32(len);
 495         hfsplus_dump_extent(hip->cached_extents);
 496         hip->extent_state |= HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW;
 497         hip->cached_start = hip->alloc_blocks;
 498         hip->cached_blocks = len;
 499
 500         res = 0;
 501         goto out;
 502 }
 503
 504 void hfsplus_file_truncate(struct inode *inode)
 505 {
 506         struct super_block *sb = inode->i_sb;
 507         struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
 508         struct hfs_find_data fd;
 509         u32 alloc_cnt, blk_cnt, start;
 510         int res;
 511
 512         dprint(DBG_INODE, "truncate: %lu, %llu -> %llu\n",
 513                 inode->i_ino, (long long)hip->phys_size,
 514                 inode->i_size);
 515
 516         if (inode->i_size > hip->phys_size) {
 517                 struct address_space *mapping = inode->i_mapping;
 518                 struct page *page;
 519                 void *fsdata;
 520                 loff_t size = inode->i_size;
 521
 522                 res = pagecache_write_begin(NULL, mapping, size, 0,
 523                                                 AOP_FLAG_UNINTERRUPTIBLE,
 524                                                 &page, &fsdata);
 525                 if (res)
 526                         return;
 527                 res = pagecache_write_end(NULL, mapping, size,
 528                         0, 0, page, fsdata);
 529                 if (res < 0)
 530                         return;
 531                 mark_inode_dirty(inode);
 532                 return;
 533         } else if (inode->i_size == hip->phys_size)
 534                 return;
 535
 536         blk_cnt = (inode->i_size + HFSPLUS_SB(sb)->alloc_blksz - 1) >>
 537                         HFSPLUS_SB(sb)->alloc_blksz_shift;
 538         alloc_cnt = hip->alloc_blocks;
 539         if (blk_cnt == alloc_cnt)
 540                 goto out;
 541
 542         mutex_lock(&hip->extents_lock);
 543         res = hfs_find_init(HFSPLUS_SB(sb)->ext_tree, &fd);
 544         if (res) {
 545                 mutex_unlock(&hip->extents_lock);
 546                 /* XXX: We lack error handling of hfsplus_file_truncate() */
 547                 return;
 548         }
 549         while (1) {
 550                 if (alloc_cnt == hip->first_blocks) {
 551                         hfsplus_free_extents(sb, hip->first_extents,
 552                                              alloc_cnt, alloc_cnt - blk_cnt);
 553                         hfsplus_dump_extent(hip->first_extents);
 554                         hip->first_blocks = blk_cnt;
 555                         break;
 556                 }
 557                 res = __hfsplus_ext_cache_extent(&fd, inode, alloc_cnt);
 558                 if (res)
 559                         break;
 560                 start = hip->cached_start;
 561                 hfsplus_free_extents(sb, hip->cached_extents,
 562                                      alloc_cnt - start, alloc_cnt - blk_cnt);
 563                 hfsplus_dump_extent(hip->cached_extents);
 564                 if (blk_cnt > start) {
 565                         hip->extent_state |= HFSPLUS_EXT_DIRTY;
 566                         break;
 567                 }
 568                 alloc_cnt = start;
 569                 hip->cached_start = hip->cached_blocks = 0;
 570                 hip->extent_state &= ~(HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW);
 571                 hfs_brec_remove(&fd);
 572         }
 573         hfs_find_exit(&fd);
 574         mutex_unlock(&hip->extents_lock);
 575
 576         hip->alloc_blocks = blk_cnt;
 577 out:
 578         hip->phys_size = inode->i_size;
 579         hip->fs_blocks = (inode->i_size + sb->s_blocksize - 1) >>
 580                 sb->s_blocksize_bits;
 581         inode_set_bytes(inode, hip->fs_blocks << sb->s_blocksize_bits);
 582         hfsplus_mark_inode_dirty(inode, HFSPLUS_I_ALLOC_DIRTY);
 583 }