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, hfs_find_rec_by_key);
  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, hfs_find_rec_by_key);
 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         int err = 0;
 333
 334         hfsplus_dump_extent(extent);
 335         for (i = 0; i < 8; extent++, i++) {
 336                 count = be32_to_cpu(extent->block_count);
 337                 if (offset == count)
 338                         goto found;
 339                 else if (offset < count)
 340                         break;
 341                 offset -= count;
 342         }
 343         /* panic? */
 344         return -EIO;
 345 found:
 346         for (;;) {
 347                 start = be32_to_cpu(extent->start_block);
 348                 if (count <= block_nr) {
 349                         err = hfsplus_block_free(sb, start, count);
 350                         if (err) {
 351                                 printk(KERN_ERR "hfs: can't free extent\n");
 352                                 dprint(DBG_EXTENT, " start: %u count: %u\n",
 353                                         start, count);
 354                         }
 355                         extent->block_count = 0;
 356                         extent->start_block = 0;
 357                         block_nr -= count;
 358                 } else {
 359                         count -= block_nr;
 360                         err = hfsplus_block_free(sb, start + count, block_nr);
 361                         if (err) {
 362                                 printk(KERN_ERR "hfs: can't free extent\n");
 363                                 dprint(DBG_EXTENT, " start: %u count: %u\n",
 364                                         start, count);
 365                         }
 366                         extent->block_count = cpu_to_be32(count);
 367                         block_nr = 0;
 368                 }
 369                 if (!block_nr || !i) {
 370                         /*
 371                          * Try to free all extents and
 372                          * return only last error
 373                          */
 374                         return err;
 375                 }
 376                 i--;
 377                 extent--;
 378                 count = be32_to_cpu(extent->block_count);
 379         }
 380 }
 381
 382 int hfsplus_free_fork(struct super_block *sb, u32 cnid,
 383                 struct hfsplus_fork_raw *fork, int type)
 384 {
 385         struct hfs_find_data fd;
 386         hfsplus_extent_rec ext_entry;
 387         u32 total_blocks, blocks, start;
 388         int res, i;
 389
 390         total_blocks = be32_to_cpu(fork->total_blocks);
 391         if (!total_blocks)
 392                 return 0;
 393
 394         blocks = 0;
 395         for (i = 0; i < 8; i++)
 396                 blocks += be32_to_cpu(fork->extents[i].block_count);
 397
 398         res = hfsplus_free_extents(sb, fork->extents, blocks, blocks);
 399         if (res)
 400                 return res;
 401         if (total_blocks == blocks)
 402                 return 0;
 403
 404         res = hfs_find_init(HFSPLUS_SB(sb)->ext_tree, &fd);
 405         if (res)
 406                 return res;
 407         do {
 408                 res = __hfsplus_ext_read_extent(&fd, ext_entry, cnid,
 409                                                 total_blocks, type);
 410                 if (res)
 411                         break;
 412                 start = be32_to_cpu(fd.key->ext.start_block);
 413                 hfsplus_free_extents(sb, ext_entry,
 414                                      total_blocks - start,
 415                                      total_blocks);
 416                 hfs_brec_remove(&fd);
 417                 total_blocks = start;
 418         } while (total_blocks > blocks);
 419         hfs_find_exit(&fd);
 420
 421         return res;
 422 }
 423
 424 int hfsplus_file_extend(struct inode *inode)
 425 {
 426         struct super_block *sb = inode->i_sb;
 427         struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
 428         struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
 429         u32 start, len, goal;
 430         int res;
 431
 432         if (sbi->alloc_file->i_size * 8 <
 433             sbi->total_blocks - sbi->free_blocks + 8) {
 434                 /* extend alloc file */
 435                 printk(KERN_ERR "hfs: extend alloc file! "
 436                                 "(%llu,%u,%u)\n",
 437                         sbi->alloc_file->i_size * 8,
 438                         sbi->total_blocks, sbi->free_blocks);
 439                 return -ENOSPC;
 440         }
 441
 442         mutex_lock(&hip->extents_lock);
 443         if (hip->alloc_blocks == hip->first_blocks)
 444                 goal = hfsplus_ext_lastblock(hip->first_extents);
 445         else {
 446                 res = hfsplus_ext_read_extent(inode, hip->alloc_blocks);
 447                 if (res)
 448                         goto out;
 449                 goal = hfsplus_ext_lastblock(hip->cached_extents);
 450         }
 451
 452         len = hip->clump_blocks;
 453         start = hfsplus_block_allocate(sb, sbi->total_blocks, goal, &len);
 454         if (start >= sbi->total_blocks) {
 455                 start = hfsplus_block_allocate(sb, goal, 0, &len);
 456                 if (start >= goal) {
 457                         res = -ENOSPC;
 458                         goto out;
 459                 }
 460         }
 461
 462         dprint(DBG_EXTENT, "extend %lu: %u,%u\n", inode->i_ino, start, len);
 463
 464         if (hip->alloc_blocks <= hip->first_blocks) {
 465                 if (!hip->first_blocks) {
 466                         dprint(DBG_EXTENT, "first extents\n");
 467                         /* no extents yet */
 468                         hip->first_extents[0].start_block = cpu_to_be32(start);
 469                         hip->first_extents[0].block_count = cpu_to_be32(len);
 470                         res = 0;
 471                 } else {
 472                         /* try to append to extents in inode */
 473                         res = hfsplus_add_extent(hip->first_extents,
 474                                                  hip->alloc_blocks,
 475                                                  start, len);
 476                         if (res == -ENOSPC)
 477                                 goto insert_extent;
 478                 }
 479                 if (!res) {
 480                         hfsplus_dump_extent(hip->first_extents);
 481                         hip->first_blocks += len;
 482                 }
 483         } else {
 484                 res = hfsplus_add_extent(hip->cached_extents,
 485                                          hip->alloc_blocks - hip->cached_start,
 486                                          start, len);
 487                 if (!res) {
 488                         hfsplus_dump_extent(hip->cached_extents);
 489                         hip->extent_state |= HFSPLUS_EXT_DIRTY;
 490                         hip->cached_blocks += len;
 491                 } else if (res == -ENOSPC)
 492                         goto insert_extent;
 493         }
 494 out:
 495         mutex_unlock(&hip->extents_lock);
 496         if (!res) {
 497                 hip->alloc_blocks += len;
 498                 hfsplus_mark_inode_dirty(inode, HFSPLUS_I_ALLOC_DIRTY);
 499         }
 500         return res;
 501
 502 insert_extent:
 503         dprint(DBG_EXTENT, "insert new extent\n");
 504         res = hfsplus_ext_write_extent_locked(inode);
 505         if (res)
 506                 goto out;
 507
 508         memset(hip->cached_extents, 0, sizeof(hfsplus_extent_rec));
 509         hip->cached_extents[0].start_block = cpu_to_be32(start);
 510         hip->cached_extents[0].block_count = cpu_to_be32(len);
 511         hfsplus_dump_extent(hip->cached_extents);
 512         hip->extent_state |= HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW;
 513         hip->cached_start = hip->alloc_blocks;
 514         hip->cached_blocks = len;
 515
 516         res = 0;
 517         goto out;
 518 }
 519
 520 void hfsplus_file_truncate(struct inode *inode)
 521 {
 522         struct super_block *sb = inode->i_sb;
 523         struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
 524         struct hfs_find_data fd;
 525         u32 alloc_cnt, blk_cnt, start;
 526         int res;
 527
 528         dprint(DBG_INODE, "truncate: %lu, %llu -> %llu\n",
 529                 inode->i_ino, (long long)hip->phys_size,
 530                 inode->i_size);
 531
 532         if (inode->i_size > hip->phys_size) {
 533                 struct address_space *mapping = inode->i_mapping;
 534                 struct page *page;
 535                 void *fsdata;
 536                 u32 size = inode->i_size;
 537
 538                 res = pagecache_write_begin(NULL, mapping, size, 0,
 539                                                 AOP_FLAG_UNINTERRUPTIBLE,
 540                                                 &page, &fsdata);
 541                 if (res)
 542                         return;
 543                 res = pagecache_write_end(NULL, mapping, size,
 544                         0, 0, page, fsdata);
 545                 if (res < 0)
 546                         return;
 547                 mark_inode_dirty(inode);
 548                 return;
 549         } else if (inode->i_size == hip->phys_size)
 550                 return;
 551
 552         blk_cnt = (inode->i_size + HFSPLUS_SB(sb)->alloc_blksz - 1) >>
 553                         HFSPLUS_SB(sb)->alloc_blksz_shift;
 554         alloc_cnt = hip->alloc_blocks;
 555         if (blk_cnt == alloc_cnt)
 556                 goto out;
 557
 558         mutex_lock(&hip->extents_lock);
 559         res = hfs_find_init(HFSPLUS_SB(sb)->ext_tree, &fd);
 560         if (res) {
 561                 mutex_unlock(&hip->extents_lock);
 562                 /* XXX: We lack error handling of hfsplus_file_truncate() */
 563                 return;
 564         }
 565         while (1) {
 566                 if (alloc_cnt == hip->first_blocks) {
 567                         hfsplus_free_extents(sb, hip->first_extents,
 568                                              alloc_cnt, alloc_cnt - blk_cnt);
 569                         hfsplus_dump_extent(hip->first_extents);
 570                         hip->first_blocks = blk_cnt;
 571                         break;
 572                 }
 573                 res = __hfsplus_ext_cache_extent(&fd, inode, alloc_cnt);
 574                 if (res)
 575                         break;
 576                 start = hip->cached_start;
 577                 hfsplus_free_extents(sb, hip->cached_extents,
 578                                      alloc_cnt - start, alloc_cnt - blk_cnt);
 579                 hfsplus_dump_extent(hip->cached_extents);
 580                 if (blk_cnt > start) {
 581                         hip->extent_state |= HFSPLUS_EXT_DIRTY;
 582                         break;
 583                 }
 584                 alloc_cnt = start;
 585                 hip->cached_start = hip->cached_blocks = 0;
 586                 hip->extent_state &= ~(HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW);
 587                 hfs_brec_remove(&fd);
 588         }
 589         hfs_find_exit(&fd);
 590         mutex_unlock(&hip->extents_lock);
 591
 592         hip->alloc_blocks = blk_cnt;
 593 out:
 594         hip->phys_size = inode->i_size;
 595         hip->fs_blocks = (inode->i_size + sb->s_blocksize - 1) >>
 596                 sb->s_blocksize_bits;
 597         inode_set_bytes(inode, hip->fs_blocks << sb->s_blocksize_bits);
 598         hfsplus_mark_inode_dirty(inode, HFSPLUS_I_ALLOC_DIRTY);
 599 }