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         hfs_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         hfs_dbg(EXTENT, "   ");
 292         for (i = 0; i < 8; i++)
 293                 hfs_dbg_cont(EXTENT, " %u:%u",
 294                              be32_to_cpu(extent[i].start_block),
 295                              be32_to_cpu(extent[i].block_count));
 296         hfs_dbg_cont(EXTENT, "\n");
 297 }
 298
 299 static int hfsplus_add_extent(struct hfsplus_extent *extent, u32 offset,
 300                               u32 alloc_block, u32 block_count)
 301 {
 302         u32 count, start;
 303         int i;
 304
 305         hfsplus_dump_extent(extent);
 306         for (i = 0; i < 8; extent++, i++) {
 307                 count = be32_to_cpu(extent->block_count);
 308                 if (offset == count) {
 309                         start = be32_to_cpu(extent->start_block);
 310                         if (alloc_block != start + count) {
 311                                 if (++i >= 8)
 312                                         return -ENOSPC;
 313                                 extent++;
 314                                 extent->start_block = cpu_to_be32(alloc_block);
 315                         } else
 316                                 block_count += count;
 317                         extent->block_count = cpu_to_be32(block_count);
 318                         return 0;
 319                 } else if (offset < count)
 320                         break;
 321                 offset -= count;
 322         }
 323         /* panic? */
 324         return -EIO;
 325 }
 326
 327 static int hfsplus_free_extents(struct super_block *sb,
 328                                 struct hfsplus_extent *extent,
 329                                 u32 offset, u32 block_nr)
 330 {
 331         u32 count, start;
 332         int i;
 333         int err = 0;
 334
 335         hfsplus_dump_extent(extent);
 336         for (i = 0; i < 8; extent++, i++) {
 337                 count = be32_to_cpu(extent->block_count);
 338                 if (offset == count)
 339                         goto found;
 340                 else if (offset < count)
 341                         break;
 342                 offset -= count;
 343         }
 344         /* panic? */
 345         return -EIO;
 346 found:
 347         for (;;) {
 348                 start = be32_to_cpu(extent->start_block);
 349                 if (count <= block_nr) {
 350                         err = hfsplus_block_free(sb, start, count);
 351                         if (err) {
 352                                 pr_err("can't free extent\n");
 353                                 hfs_dbg(EXTENT, " start: %u count: %u\n",
 354                                         start, count);
 355                         }
 356                         extent->block_count = 0;
 357                         extent->start_block = 0;
 358                         block_nr -= count;
 359                 } else {
 360                         count -= block_nr;
 361                         err = hfsplus_block_free(sb, start + count, block_nr);
 362                         if (err) {
 363                                 pr_err("can't free extent\n");
 364                                 hfs_dbg(EXTENT, " start: %u count: %u\n",
 365                                         start, count);
 366                         }
 367                         extent->block_count = cpu_to_be32(count);
 368                         block_nr = 0;
 369                 }
 370                 if (!block_nr || !i) {
 371                         /*
 372                          * Try to free all extents and
 373                          * return only last error
 374                          */
 375                         return err;
 376                 }
 377                 i--;
 378                 extent--;
 379                 count = be32_to_cpu(extent->block_count);
 380         }
 381 }
 382
 383 int hfsplus_free_fork(struct super_block *sb, u32 cnid,
 384                 struct hfsplus_fork_raw *fork, int type)
 385 {
 386         struct hfs_find_data fd;
 387         hfsplus_extent_rec ext_entry;
 388         u32 total_blocks, blocks, start;
 389         int res, i;
 390
 391         total_blocks = be32_to_cpu(fork->total_blocks);
 392         if (!total_blocks)
 393                 return 0;
 394
 395         blocks = 0;
 396         for (i = 0; i < 8; i++)
 397                 blocks += be32_to_cpu(fork->extents[i].block_count);
 398
 399         res = hfsplus_free_extents(sb, fork->extents, blocks, blocks);
 400         if (res)
 401                 return res;
 402         if (total_blocks == blocks)
 403                 return 0;
 404
 405         res = hfs_find_init(HFSPLUS_SB(sb)->ext_tree, &fd);
 406         if (res)
 407                 return res;
 408         do {
 409                 res = __hfsplus_ext_read_extent(&fd, ext_entry, cnid,
 410                                                 total_blocks, type);
 411                 if (res)
 412                         break;
 413                 start = be32_to_cpu(fd.key->ext.start_block);
 414                 hfsplus_free_extents(sb, ext_entry,
 415                                      total_blocks - start,
 416                                      total_blocks);
 417                 hfs_brec_remove(&fd);
 418                 total_blocks = start;
 419         } while (total_blocks > blocks);
 420         hfs_find_exit(&fd);
 421
 422         return res;
 423 }
 424
 425 int hfsplus_file_extend(struct inode *inode)
 426 {
 427         struct super_block *sb = inode->i_sb;
 428         struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
 429         struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
 430         u32 start, len, goal;
 431         int res;
 432
 433         if (sbi->alloc_file->i_size * 8 <
 434             sbi->total_blocks - sbi->free_blocks + 8) {
 435                 /* extend alloc file */
 436                 pr_err("extend alloc file! "
 437                                 "(%llu,%u,%u)\n",
 438                         sbi->alloc_file->i_size * 8,
 439                         sbi->total_blocks, sbi->free_blocks);
 440                 return -ENOSPC;
 441         }
 442
 443         mutex_lock(&hip->extents_lock);
 444         if (hip->alloc_blocks == hip->first_blocks)
 445                 goal = hfsplus_ext_lastblock(hip->first_extents);
 446         else {
 447                 res = hfsplus_ext_read_extent(inode, hip->alloc_blocks);
 448                 if (res)
 449                         goto out;
 450                 goal = hfsplus_ext_lastblock(hip->cached_extents);
 451         }
 452
 453         len = hip->clump_blocks;
 454         start = hfsplus_block_allocate(sb, sbi->total_blocks, goal, &len);
 455         if (start >= sbi->total_blocks) {
 456                 start = hfsplus_block_allocate(sb, goal, 0, &len);
 457                 if (start >= goal) {
 458                         res = -ENOSPC;
 459                         goto out;
 460                 }
 461         }
 462
 463         hfs_dbg(EXTENT, "extend %lu: %u,%u\n", inode->i_ino, start, len);
 464
 465         if (hip->alloc_blocks <= hip->first_blocks) {
 466                 if (!hip->first_blocks) {
 467                         hfs_dbg(EXTENT, "first extents\n");
 468                         /* no extents yet */
 469                         hip->first_extents[0].start_block = cpu_to_be32(start);
 470                         hip->first_extents[0].block_count = cpu_to_be32(len);
 471                         res = 0;
 472                 } else {
 473                         /* try to append to extents in inode */
 474                         res = hfsplus_add_extent(hip->first_extents,
 475                                                  hip->alloc_blocks,
 476                                                  start, len);
 477                         if (res == -ENOSPC)
 478                                 goto insert_extent;
 479                 }
 480                 if (!res) {
 481                         hfsplus_dump_extent(hip->first_extents);
 482                         hip->first_blocks += len;
 483                 }
 484         } else {
 485                 res = hfsplus_add_extent(hip->cached_extents,
 486                                          hip->alloc_blocks - hip->cached_start,
 487                                          start, len);
 488                 if (!res) {
 489                         hfsplus_dump_extent(hip->cached_extents);
 490                         hip->extent_state |= HFSPLUS_EXT_DIRTY;
 491                         hip->cached_blocks += len;
 492                 } else if (res == -ENOSPC)
 493                         goto insert_extent;
 494         }
 495 out:
 496         mutex_unlock(&hip->extents_lock);
 497         if (!res) {
 498                 hip->alloc_blocks += len;
 499                 hfsplus_mark_inode_dirty(inode, HFSPLUS_I_ALLOC_DIRTY);
 500         }
 501         return res;
 502
 503 insert_extent:
 504         hfs_dbg(EXTENT, "insert new extent\n");
 505         res = hfsplus_ext_write_extent_locked(inode);
 506         if (res)
 507                 goto out;
 508
 509         memset(hip->cached_extents, 0, sizeof(hfsplus_extent_rec));
 510         hip->cached_extents[0].start_block = cpu_to_be32(start);
 511         hip->cached_extents[0].block_count = cpu_to_be32(len);
 512         hfsplus_dump_extent(hip->cached_extents);
 513         hip->extent_state |= HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW;
 514         hip->cached_start = hip->alloc_blocks;
 515         hip->cached_blocks = len;
 516
 517         res = 0;
 518         goto out;
 519 }
 520
 521 void hfsplus_file_truncate(struct inode *inode)
 522 {
 523         struct super_block *sb = inode->i_sb;
 524         struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
 525         struct hfs_find_data fd;
 526         u32 alloc_cnt, blk_cnt, start;
 527         int res;
 528
 529         hfs_dbg(INODE, "truncate: %lu, %llu -> %llu\n",
 530                 inode->i_ino, (long long)hip->phys_size, 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                 loff_t 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 }