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 int __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 res;
 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 res;
 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         return 0;
 122 }
 123
 124 static int hfsplus_ext_write_extent_locked(struct inode *inode)
 125 {
 126         int res = 0;
 127
 128         if (HFSPLUS_I(inode)->extent_state & HFSPLUS_EXT_DIRTY) {
 129                 struct hfs_find_data fd;
 130
 131                 res = hfs_find_init(HFSPLUS_SB(inode->i_sb)->ext_tree, &fd);
 132                 if (res)
 133                         return res;
 134                 res = __hfsplus_ext_write_extent(inode, &fd);
 135                 hfs_find_exit(&fd);
 136         }
 137         return res;
 138 }
 139
 140 int hfsplus_ext_write_extent(struct inode *inode)
 141 {
 142         int res;
 143
 144         mutex_lock(&HFSPLUS_I(inode)->extents_lock);
 145         res = hfsplus_ext_write_extent_locked(inode);
 146         mutex_unlock(&HFSPLUS_I(inode)->extents_lock);
 147
 148         return res;
 149 }
 150
 151 static inline int __hfsplus_ext_read_extent(struct hfs_find_data *fd,
 152                                             struct hfsplus_extent *extent,
 153                                             u32 cnid, u32 block, u8 type)
 154 {
 155         int res;
 156
 157         hfsplus_ext_build_key(fd->search_key, cnid, block, type);
 158         fd->key->ext.cnid = 0;
 159         res = hfs_brec_find(fd, hfs_find_rec_by_key);
 160         if (res && res != -ENOENT)
 161                 return res;
 162         if (fd->key->ext.cnid != fd->search_key->ext.cnid ||
 163             fd->key->ext.fork_type != fd->search_key->ext.fork_type)
 164                 return -ENOENT;
 165         if (fd->entrylength != sizeof(hfsplus_extent_rec))
 166                 return -EIO;
 167         hfs_bnode_read(fd->bnode, extent, fd->entryoffset,
 168                 sizeof(hfsplus_extent_rec));
 169         return 0;
 170 }
 171
 172 static inline int __hfsplus_ext_cache_extent(struct hfs_find_data *fd,
 173                 struct inode *inode, u32 block)
 174 {
 175         struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
 176         int res;
 177
 178         WARN_ON(!mutex_is_locked(&hip->extents_lock));
 179
 180         if (hip->extent_state & HFSPLUS_EXT_DIRTY) {
 181                 res = __hfsplus_ext_write_extent(inode, fd);
 182                 if (res)
 183                         return res;
 184         }
 185
 186         res = __hfsplus_ext_read_extent(fd, hip->cached_extents, inode->i_ino,
 187                                         block, HFSPLUS_IS_RSRC(inode) ?
 188                                                 HFSPLUS_TYPE_RSRC :
 189                                                 HFSPLUS_TYPE_DATA);
 190         if (!res) {
 191                 hip->cached_start = be32_to_cpu(fd->key->ext.start_block);
 192                 hip->cached_blocks =
 193                         hfsplus_ext_block_count(hip->cached_extents);
 194         } else {
 195                 hip->cached_start = hip->cached_blocks = 0;
 196                 hip->extent_state &= ~(HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW);
 197         }
 198         return res;
 199 }
 200
 201 static int hfsplus_ext_read_extent(struct inode *inode, u32 block)
 202 {
 203         struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
 204         struct hfs_find_data fd;
 205         int res;
 206
 207         if (block >= hip->cached_start &&
 208             block < hip->cached_start + hip->cached_blocks)
 209                 return 0;
 210
 211         res = hfs_find_init(HFSPLUS_SB(inode->i_sb)->ext_tree, &fd);
 212         if (!res) {
 213                 res = __hfsplus_ext_cache_extent(&fd, inode, block);
 214                 hfs_find_exit(&fd);
 215         }
 216         return res;
 217 }
 218
 219 /* Get a block at iblock for inode, possibly allocating if create */
 220 int hfsplus_get_block(struct inode *inode, sector_t iblock,
 221                       struct buffer_head *bh_result, int create)
 222 {
 223         struct super_block *sb = inode->i_sb;
 224         struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
 225         struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
 226         int res = -EIO;
 227         u32 ablock, dblock, mask;
 228         sector_t sector;
 229         int was_dirty = 0;
 230         int shift;
 231
 232         /* Convert inode block to disk allocation block */
 233         shift = sbi->alloc_blksz_shift - sb->s_blocksize_bits;
 234         ablock = iblock >> sbi->fs_shift;
 235
 236         if (iblock >= hip->fs_blocks) {
 237                 if (iblock > hip->fs_blocks || !create)
 238                         return -EIO;
 239                 if (ablock >= hip->alloc_blocks) {
 240                         res = hfsplus_file_extend(inode);
 241                         if (res)
 242                                 return res;
 243                 }
 244         } else
 245                 create = 0;
 246
 247         if (ablock < hip->first_blocks) {
 248                 dblock = hfsplus_ext_find_block(hip->first_extents, ablock);
 249                 goto done;
 250         }
 251
 252         if (inode->i_ino == HFSPLUS_EXT_CNID)
 253                 return -EIO;
 254
 255         mutex_lock(&hip->extents_lock);
 256
 257         /*
 258          * hfsplus_ext_read_extent will write out a cached extent into
 259          * the extents btree.  In that case we may have to mark the inode
 260          * dirty even for a pure read of an extent here.
 261          */
 262         was_dirty = (hip->extent_state & HFSPLUS_EXT_DIRTY);
 263         res = hfsplus_ext_read_extent(inode, ablock);
 264         if (res) {
 265                 mutex_unlock(&hip->extents_lock);
 266                 return -EIO;
 267         }
 268         dblock = hfsplus_ext_find_block(hip->cached_extents,
 269                                         ablock - hip->cached_start);
 270         mutex_unlock(&hip->extents_lock);
 271
 272 done:
 273         hfs_dbg(EXTENT, "get_block(%lu): %llu - %u\n",
 274                 inode->i_ino, (long long)iblock, dblock);
 275
 276         mask = (1 << sbi->fs_shift) - 1;
 277         sector = ((sector_t)dblock << sbi->fs_shift) +
 278                   sbi->blockoffset + (iblock & mask);
 279         map_bh(bh_result, sb, sector);
 280
 281         if (create) {
 282                 set_buffer_new(bh_result);
 283                 hip->phys_size += sb->s_blocksize;
 284                 hip->fs_blocks++;
 285                 inode_add_bytes(inode, sb->s_blocksize);
 286         }
 287         if (create || was_dirty)
 288                 mark_inode_dirty(inode);
 289         return 0;
 290 }
 291
 292 static void hfsplus_dump_extent(struct hfsplus_extent *extent)
 293 {
 294         int i;
 295
 296         hfs_dbg(EXTENT, "   ");
 297         for (i = 0; i < 8; i++)
 298                 hfs_dbg_cont(EXTENT, " %u:%u",
 299                              be32_to_cpu(extent[i].start_block),
 300                              be32_to_cpu(extent[i].block_count));
 301         hfs_dbg_cont(EXTENT, "\n");
 302 }
 303
 304 static int hfsplus_add_extent(struct hfsplus_extent *extent, u32 offset,
 305                               u32 alloc_block, u32 block_count)
 306 {
 307         u32 count, start;
 308         int i;
 309
 310         hfsplus_dump_extent(extent);
 311         for (i = 0; i < 8; extent++, i++) {
 312                 count = be32_to_cpu(extent->block_count);
 313                 if (offset == count) {
 314                         start = be32_to_cpu(extent->start_block);
 315                         if (alloc_block != start + count) {
 316                                 if (++i >= 8)
 317                                         return -ENOSPC;
 318                                 extent++;
 319                                 extent->start_block = cpu_to_be32(alloc_block);
 320                         } else
 321                                 block_count += count;
 322                         extent->block_count = cpu_to_be32(block_count);
 323                         return 0;
 324                 } else if (offset < count)
 325                         break;
 326                 offset -= count;
 327         }
 328         /* panic? */
 329         return -EIO;
 330 }
 331
 332 static int hfsplus_free_extents(struct super_block *sb,
 333                                 struct hfsplus_extent *extent,
 334                                 u32 offset, u32 block_nr)
 335 {
 336         u32 count, start;
 337         int i;
 338         int err = 0;
 339
 340         hfsplus_dump_extent(extent);
 341         for (i = 0; i < 8; extent++, i++) {
 342                 count = be32_to_cpu(extent->block_count);
 343                 if (offset == count)
 344                         goto found;
 345                 else if (offset < count)
 346                         break;
 347                 offset -= count;
 348         }
 349         /* panic? */
 350         return -EIO;
 351 found:
 352         for (;;) {
 353                 start = be32_to_cpu(extent->start_block);
 354                 if (count <= block_nr) {
 355                         err = hfsplus_block_free(sb, start, count);
 356                         if (err) {
 357                                 pr_err("can't free extent\n");
 358                                 hfs_dbg(EXTENT, " start: %u count: %u\n",
 359                                         start, count);
 360                         }
 361                         extent->block_count = 0;
 362                         extent->start_block = 0;
 363                         block_nr -= count;
 364                 } else {
 365                         count -= block_nr;
 366                         err = hfsplus_block_free(sb, start + count, block_nr);
 367                         if (err) {
 368                                 pr_err("can't free extent\n");
 369                                 hfs_dbg(EXTENT, " start: %u count: %u\n",
 370                                         start, count);
 371                         }
 372                         extent->block_count = cpu_to_be32(count);
 373                         block_nr = 0;
 374                 }
 375                 if (!block_nr || !i) {
 376                         /*
 377                          * Try to free all extents and
 378                          * return only last error
 379                          */
 380                         return err;
 381                 }
 382                 i--;
 383                 extent--;
 384                 count = be32_to_cpu(extent->block_count);
 385         }
 386 }
 387
 388 int hfsplus_free_fork(struct super_block *sb, u32 cnid,
 389                 struct hfsplus_fork_raw *fork, int type)
 390 {
 391         struct hfs_find_data fd;
 392         hfsplus_extent_rec ext_entry;
 393         u32 total_blocks, blocks, start;
 394         int res, i;
 395
 396         total_blocks = be32_to_cpu(fork->total_blocks);
 397         if (!total_blocks)
 398                 return 0;
 399
 400         blocks = 0;
 401         for (i = 0; i < 8; i++)
 402                 blocks += be32_to_cpu(fork->extents[i].block_count);
 403
 404         res = hfsplus_free_extents(sb, fork->extents, blocks, blocks);
 405         if (res)
 406                 return res;
 407         if (total_blocks == blocks)
 408                 return 0;
 409
 410         res = hfs_find_init(HFSPLUS_SB(sb)->ext_tree, &fd);
 411         if (res)
 412                 return res;
 413         do {
 414                 res = __hfsplus_ext_read_extent(&fd, ext_entry, cnid,
 415                                                 total_blocks, type);
 416                 if (res)
 417                         break;
 418                 start = be32_to_cpu(fd.key->ext.start_block);
 419                 hfsplus_free_extents(sb, ext_entry,
 420                                      total_blocks - start,
 421                                      total_blocks);
 422                 hfs_brec_remove(&fd);
 423                 total_blocks = start;
 424         } while (total_blocks > blocks);
 425         hfs_find_exit(&fd);
 426
 427         return res;
 428 }
 429
 430 int hfsplus_file_extend(struct inode *inode)
 431 {
 432         struct super_block *sb = inode->i_sb;
 433         struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
 434         struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
 435         u32 start, len, goal;
 436         int res;
 437
 438         if (sbi->alloc_file->i_size * 8 <
 439             sbi->total_blocks - sbi->free_blocks + 8) {
 440                 /* extend alloc file */
 441                 pr_err("extend alloc file! "
 442                                 "(%llu,%u,%u)\n",
 443                         sbi->alloc_file->i_size * 8,
 444                         sbi->total_blocks, sbi->free_blocks);
 445                 return -ENOSPC;
 446         }
 447
 448         mutex_lock(&hip->extents_lock);
 449         if (hip->alloc_blocks == hip->first_blocks)
 450                 goal = hfsplus_ext_lastblock(hip->first_extents);
 451         else {
 452                 res = hfsplus_ext_read_extent(inode, hip->alloc_blocks);
 453                 if (res)
 454                         goto out;
 455                 goal = hfsplus_ext_lastblock(hip->cached_extents);
 456         }
 457
 458         len = hip->clump_blocks;
 459         start = hfsplus_block_allocate(sb, sbi->total_blocks, goal, &len);
 460         if (start >= sbi->total_blocks) {
 461                 start = hfsplus_block_allocate(sb, goal, 0, &len);
 462                 if (start >= goal) {
 463                         res = -ENOSPC;
 464                         goto out;
 465                 }
 466         }
 467
 468         hfs_dbg(EXTENT, "extend %lu: %u,%u\n", inode->i_ino, start, len);
 469
 470         if (hip->alloc_blocks <= hip->first_blocks) {
 471                 if (!hip->first_blocks) {
 472                         hfs_dbg(EXTENT, "first extents\n");
 473                         /* no extents yet */
 474                         hip->first_extents[0].start_block = cpu_to_be32(start);
 475                         hip->first_extents[0].block_count = cpu_to_be32(len);
 476                         res = 0;
 477                 } else {
 478                         /* try to append to extents in inode */
 479                         res = hfsplus_add_extent(hip->first_extents,
 480                                                  hip->alloc_blocks,
 481                                                  start, len);
 482                         if (res == -ENOSPC)
 483                                 goto insert_extent;
 484                 }
 485                 if (!res) {
 486                         hfsplus_dump_extent(hip->first_extents);
 487                         hip->first_blocks += len;
 488                 }
 489         } else {
 490                 res = hfsplus_add_extent(hip->cached_extents,
 491                                          hip->alloc_blocks - hip->cached_start,
 492                                          start, len);
 493                 if (!res) {
 494                         hfsplus_dump_extent(hip->cached_extents);
 495                         hip->extent_state |= HFSPLUS_EXT_DIRTY;
 496                         hip->cached_blocks += len;
 497                 } else if (res == -ENOSPC)
 498                         goto insert_extent;
 499         }
 500 out:
 501         mutex_unlock(&hip->extents_lock);
 502         if (!res) {
 503                 hip->alloc_blocks += len;
 504                 hfsplus_mark_inode_dirty(inode, HFSPLUS_I_ALLOC_DIRTY);
 505         }
 506         return res;
 507
 508 insert_extent:
 509         hfs_dbg(EXTENT, "insert new extent\n");
 510         res = hfsplus_ext_write_extent_locked(inode);
 511         if (res)
 512                 goto out;
 513
 514         memset(hip->cached_extents, 0, sizeof(hfsplus_extent_rec));
 515         hip->cached_extents[0].start_block = cpu_to_be32(start);
 516         hip->cached_extents[0].block_count = cpu_to_be32(len);
 517         hfsplus_dump_extent(hip->cached_extents);
 518         hip->extent_state |= HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW;
 519         hip->cached_start = hip->alloc_blocks;
 520         hip->cached_blocks = len;
 521
 522         res = 0;
 523         goto out;
 524 }
 525
 526 void hfsplus_file_truncate(struct inode *inode)
 527 {
 528         struct super_block *sb = inode->i_sb;
 529         struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
 530         struct hfs_find_data fd;
 531         u32 alloc_cnt, blk_cnt, start;
 532         int res;
 533
 534         hfs_dbg(INODE, "truncate: %lu, %llu -> %llu\n",
 535                 inode->i_ino, (long long)hip->phys_size, inode->i_size);
 536
 537         if (inode->i_size > hip->phys_size) {
 538                 struct address_space *mapping = inode->i_mapping;
 539                 struct page *page;
 540                 void *fsdata;
 541                 loff_t size = inode->i_size;
 542
 543                 res = pagecache_write_begin(NULL, mapping, size, 0,
 544                                                 AOP_FLAG_UNINTERRUPTIBLE,
 545                                                 &page, &fsdata);
 546                 if (res)
 547                         return;
 548                 res = pagecache_write_end(NULL, mapping, size,
 549                         0, 0, page, fsdata);
 550                 if (res < 0)
 551                         return;
 552                 mark_inode_dirty(inode);
 553                 return;
 554         } else if (inode->i_size == hip->phys_size)
 555                 return;
 556
 557         blk_cnt = (inode->i_size + HFSPLUS_SB(sb)->alloc_blksz - 1) >>
 558                         HFSPLUS_SB(sb)->alloc_blksz_shift;
 559         alloc_cnt = hip->alloc_blocks;
 560         if (blk_cnt == alloc_cnt)
 561                 goto out;
 562
 563         mutex_lock(&hip->extents_lock);
 564         res = hfs_find_init(HFSPLUS_SB(sb)->ext_tree, &fd);
 565         if (res) {
 566                 mutex_unlock(&hip->extents_lock);
 567                 /* XXX: We lack error handling of hfsplus_file_truncate() */
 568                 return;
 569         }
 570         while (1) {
 571                 if (alloc_cnt == hip->first_blocks) {
 572                         hfsplus_free_extents(sb, hip->first_extents,
 573                                              alloc_cnt, alloc_cnt - blk_cnt);
 574                         hfsplus_dump_extent(hip->first_extents);
 575                         hip->first_blocks = blk_cnt;
 576                         break;
 577                 }
 578                 res = __hfsplus_ext_cache_extent(&fd, inode, alloc_cnt);
 579                 if (res)
 580                         break;
 581                 start = hip->cached_start;
 582                 hfsplus_free_extents(sb, hip->cached_extents,
 583                                      alloc_cnt - start, alloc_cnt - blk_cnt);
 584                 hfsplus_dump_extent(hip->cached_extents);
 585                 if (blk_cnt > start) {
 586                         hip->extent_state |= HFSPLUS_EXT_DIRTY;
 587                         break;
 588                 }
 589                 alloc_cnt = start;
 590                 hip->cached_start = hip->cached_blocks = 0;
 591                 hip->extent_state &= ~(HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW);
 592                 hfs_brec_remove(&fd);
 593         }
 594         hfs_find_exit(&fd);
 595         mutex_unlock(&hip->extents_lock);
 596
 597         hip->alloc_blocks = blk_cnt;
 598 out:
 599         hip->phys_size = inode->i_size;
 600         hip->fs_blocks = (inode->i_size + sb->s_blocksize - 1) >>
 601                 sb->s_blocksize_bits;
 602         inode_set_bytes(inode, hip->fs_blocks << sb->s_blocksize_bits);
 603         hfsplus_mark_inode_dirty(inode, HFSPLUS_I_ALLOC_DIRTY);
 604 }