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, struct hfs_find_data *fd)
  87 {
  88         struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
  89         int res;
  90
  91         WARN_ON(!mutex_is_locked(&hip->extents_lock));
  92
  93         hfsplus_ext_build_key(fd->search_key, inode->i_ino, hip->cached_start,
  94                               HFSPLUS_IS_RSRC(inode) ?
  95                                 HFSPLUS_TYPE_RSRC : HFSPLUS_TYPE_DATA);
  96
  97         res = hfs_brec_find(fd);
  98         if (hip->extent_state & HFSPLUS_EXT_NEW) {
  99                 if (res != -ENOENT)
 100                         return;
 101                 hfs_brec_insert(fd, hip->cached_extents,
 102                                 sizeof(hfsplus_extent_rec));
 103                 hip->extent_state &= ~(HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW);
 104         } else {
 105                 if (res)
 106                         return;
 107                 hfs_bnode_write(fd->bnode, hip->cached_extents,
 108                                 fd->entryoffset, fd->entrylength);
 109                 hip->extent_state &= ~HFSPLUS_EXT_DIRTY;
 110         }
 111
 112         /*
 113          * We can't just use hfsplus_mark_inode_dirty here, because we
 114          * also get called from hfsplus_write_inode, which should not
 115          * redirty the inode.  Instead the callers have to be careful
 116          * to explicily mark the inode dirty, too.
 117          */
 118         set_bit(HFSPLUS_I_EXT_DIRTY, &hip->flags);
 119 }
 120
 121 static void hfsplus_ext_write_extent_locked(struct inode *inode)
 122 {
 123         if (HFSPLUS_I(inode)->extent_state & HFSPLUS_EXT_DIRTY) {
 124                 struct hfs_find_data fd;
 125
 126                 hfs_find_init(HFSPLUS_SB(inode->i_sb)->ext_tree, &fd);
 127                 __hfsplus_ext_write_extent(inode, &fd);
 128                 hfs_find_exit(&fd);
 129         }
 130 }
 131
 132 void hfsplus_ext_write_extent(struct inode *inode)
 133 {
 134         mutex_lock(&HFSPLUS_I(inode)->extents_lock);
 135         hfsplus_ext_write_extent_locked(inode);
 136         mutex_unlock(&HFSPLUS_I(inode)->extents_lock);
 137 }
 138
 139 static inline int __hfsplus_ext_read_extent(struct hfs_find_data *fd,
 140                                             struct hfsplus_extent *extent,
 141                                             u32 cnid, u32 block, u8 type)
 142 {
 143         int res;
 144
 145         hfsplus_ext_build_key(fd->search_key, cnid, block, type);
 146         fd->key->ext.cnid = 0;
 147         res = hfs_brec_find(fd);
 148         if (res && res != -ENOENT)
 149                 return res;
 150         if (fd->key->ext.cnid != fd->search_key->ext.cnid ||
 151             fd->key->ext.fork_type != fd->search_key->ext.fork_type)
 152                 return -ENOENT;
 153         if (fd->entrylength != sizeof(hfsplus_extent_rec))
 154                 return -EIO;
 155         hfs_bnode_read(fd->bnode, extent, fd->entryoffset, sizeof(hfsplus_extent_rec));
 156         return 0;
 157 }
 158
 159 static inline int __hfsplus_ext_cache_extent(struct hfs_find_data *fd, struct inode *inode, u32 block)
 160 {
 161         struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
 162         int res;
 163
 164         WARN_ON(!mutex_is_locked(&hip->extents_lock));
 165
 166         if (hip->extent_state & HFSPLUS_EXT_DIRTY)
 167                 __hfsplus_ext_write_extent(inode, fd);
 168
 169         res = __hfsplus_ext_read_extent(fd, hip->cached_extents, inode->i_ino,
 170                                         block, HFSPLUS_IS_RSRC(inode) ?
 171                                                 HFSPLUS_TYPE_RSRC :
 172                                                 HFSPLUS_TYPE_DATA);
 173         if (!res) {
 174                 hip->cached_start = be32_to_cpu(fd->key->ext.start_block);
 175                 hip->cached_blocks = hfsplus_ext_block_count(hip->cached_extents);
 176         } else {
 177                 hip->cached_start = hip->cached_blocks = 0;
 178                 hip->extent_state &= ~(HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW);
 179         }
 180         return res;
 181 }
 182
 183 static int hfsplus_ext_read_extent(struct inode *inode, u32 block)
 184 {
 185         struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
 186         struct hfs_find_data fd;
 187         int res;
 188
 189         if (block >= hip->cached_start &&
 190             block < hip->cached_start + hip->cached_blocks)
 191                 return 0;
 192
 193         hfs_find_init(HFSPLUS_SB(inode->i_sb)->ext_tree, &fd);
 194         res = __hfsplus_ext_cache_extent(&fd, inode, block);
 195         hfs_find_exit(&fd);
 196         return res;
 197 }
 198
 199 /* Get a block at iblock for inode, possibly allocating if create */
 200 int hfsplus_get_block(struct inode *inode, sector_t iblock,
 201                       struct buffer_head *bh_result, int create)
 202 {
 203         struct super_block *sb = inode->i_sb;
 204         struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
 205         struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
 206         int res = -EIO;
 207         u32 ablock, dblock, mask;
 208         int was_dirty = 0;
 209         int shift;
 210
 211         /* Convert inode block to disk allocation block */
 212         shift = sbi->alloc_blksz_shift - sb->s_blocksize_bits;
 213         ablock = iblock >> sbi->fs_shift;
 214
 215         if (iblock >= hip->fs_blocks) {
 216                 if (iblock > hip->fs_blocks || !create)
 217                         return -EIO;
 218                 if (ablock >= hip->alloc_blocks) {
 219                         res = hfsplus_file_extend(inode);
 220                         if (res)
 221                                 return res;
 222                 }
 223         } else
 224                 create = 0;
 225
 226         if (ablock < hip->first_blocks) {
 227                 dblock = hfsplus_ext_find_block(hip->first_extents, ablock);
 228                 goto done;
 229         }
 230
 231         if (inode->i_ino == HFSPLUS_EXT_CNID)
 232                 return -EIO;
 233
 234         mutex_lock(&hip->extents_lock);
 235
 236         /*
 237          * hfsplus_ext_read_extent will write out a cached extent into
 238          * the extents btree.  In that case we may have to mark the inode
 239          * dirty even for a pure read of an extent here.
 240          */
 241         was_dirty = (hip->extent_state & HFSPLUS_EXT_DIRTY);
 242         res = hfsplus_ext_read_extent(inode, ablock);
 243         if (res) {
 244                 mutex_unlock(&hip->extents_lock);
 245                 return -EIO;
 246         }
 247         dblock = hfsplus_ext_find_block(hip->cached_extents,
 248                                         ablock - hip->cached_start);
 249         mutex_unlock(&hip->extents_lock);
 250
 251 done:
 252         dprint(DBG_EXTENT, "get_block(%lu): %llu - %u\n", inode->i_ino, (long long)iblock, dblock);
 253         mask = (1 << sbi->fs_shift) - 1;
 254         map_bh(bh_result, sb, (dblock << sbi->fs_shift) + sbi->blockoffset + (iblock & mask));
 255         if (create) {
 256                 set_buffer_new(bh_result);
 257                 hip->phys_size += sb->s_blocksize;
 258                 hip->fs_blocks++;
 259                 inode_add_bytes(inode, sb->s_blocksize);
 260         }
 261         if (create || was_dirty)
 262                 mark_inode_dirty(inode);
 263         return 0;
 264 }
 265
 266 static void hfsplus_dump_extent(struct hfsplus_extent *extent)
 267 {
 268         int i;
 269
 270         dprint(DBG_EXTENT, "   ");
 271         for (i = 0; i < 8; i++)
 272                 dprint(DBG_EXTENT, " %u:%u", be32_to_cpu(extent[i].start_block),
 273                                  be32_to_cpu(extent[i].block_count));
 274         dprint(DBG_EXTENT, "\n");
 275 }
 276
 277 static int hfsplus_add_extent(struct hfsplus_extent *extent, u32 offset,
 278                               u32 alloc_block, u32 block_count)
 279 {
 280         u32 count, start;
 281         int i;
 282
 283         hfsplus_dump_extent(extent);
 284         for (i = 0; i < 8; extent++, i++) {
 285                 count = be32_to_cpu(extent->block_count);
 286                 if (offset == count) {
 287                         start = be32_to_cpu(extent->start_block);
 288                         if (alloc_block != start + count) {
 289                                 if (++i >= 8)
 290                                         return -ENOSPC;
 291                                 extent++;
 292                                 extent->start_block = cpu_to_be32(alloc_block);
 293                         } else
 294                                 block_count += count;
 295                         extent->block_count = cpu_to_be32(block_count);
 296                         return 0;
 297                 } else if (offset < count)
 298                         break;
 299                 offset -= count;
 300         }
 301         /* panic? */
 302         return -EIO;
 303 }
 304
 305 static int hfsplus_free_extents(struct super_block *sb,
 306                                 struct hfsplus_extent *extent,
 307                                 u32 offset, u32 block_nr)
 308 {
 309         u32 count, start;
 310         int i;
 311
 312         hfsplus_dump_extent(extent);
 313         for (i = 0; i < 8; extent++, i++) {
 314                 count = be32_to_cpu(extent->block_count);
 315                 if (offset == count)
 316                         goto found;
 317                 else if (offset < count)
 318                         break;
 319                 offset -= count;
 320         }
 321         /* panic? */
 322         return -EIO;
 323 found:
 324         for (;;) {
 325                 start = be32_to_cpu(extent->start_block);
 326                 if (count <= block_nr) {
 327                         hfsplus_block_free(sb, start, count);
 328                         extent->block_count = 0;
 329                         extent->start_block = 0;
 330                         block_nr -= count;
 331                 } else {
 332                         count -= block_nr;
 333                         hfsplus_block_free(sb, start + count, block_nr);
 334                         extent->block_count = cpu_to_be32(count);
 335                         block_nr = 0;
 336                 }
 337                 if (!block_nr || !i)
 338                         return 0;
 339                 i--;
 340                 extent--;
 341                 count = be32_to_cpu(extent->block_count);
 342         }
 343 }
 344
 345 int hfsplus_free_fork(struct super_block *sb, u32 cnid, struct hfsplus_fork_raw *fork, int type)
 346 {
 347         struct hfs_find_data fd;
 348         hfsplus_extent_rec ext_entry;
 349         u32 total_blocks, blocks, start;
 350         int res, i;
 351
 352         total_blocks = be32_to_cpu(fork->total_blocks);
 353         if (!total_blocks)
 354                 return 0;
 355
 356         blocks = 0;
 357         for (i = 0; i < 8; i++)
 358                 blocks += be32_to_cpu(fork->extents[i].block_count);
 359
 360         res = hfsplus_free_extents(sb, fork->extents, blocks, blocks);
 361         if (res)
 362                 return res;
 363         if (total_blocks == blocks)
 364                 return 0;
 365
 366         hfs_find_init(HFSPLUS_SB(sb)->ext_tree, &fd);
 367         do {
 368                 res = __hfsplus_ext_read_extent(&fd, ext_entry, cnid,
 369                                                 total_blocks, type);
 370                 if (res)
 371                         break;
 372                 start = be32_to_cpu(fd.key->ext.start_block);
 373                 hfsplus_free_extents(sb, ext_entry,
 374                                      total_blocks - start,
 375                                      total_blocks);
 376                 hfs_brec_remove(&fd);
 377                 total_blocks = start;
 378         } while (total_blocks > blocks);
 379         hfs_find_exit(&fd);
 380
 381         return res;
 382 }
 383
 384 int hfsplus_file_extend(struct inode *inode)
 385 {
 386         struct super_block *sb = inode->i_sb;
 387         struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
 388         struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
 389         u32 start, len, goal;
 390         int res;
 391
 392         if (sbi->alloc_file->i_size * 8 <
 393             sbi->total_blocks - sbi->free_blocks + 8) {
 394                 // extend alloc file
 395                 printk(KERN_ERR "hfs: extend alloc file! (%Lu,%u,%u)\n",
 396                                 sbi->alloc_file->i_size * 8,
 397                                 sbi->total_blocks, sbi->free_blocks);
 398                 return -ENOSPC;
 399         }
 400
 401         mutex_lock(&hip->extents_lock);
 402         if (hip->alloc_blocks == hip->first_blocks)
 403                 goal = hfsplus_ext_lastblock(hip->first_extents);
 404         else {
 405                 res = hfsplus_ext_read_extent(inode, hip->alloc_blocks);
 406                 if (res)
 407                         goto out;
 408                 goal = hfsplus_ext_lastblock(hip->cached_extents);
 409         }
 410
 411         len = hip->clump_blocks;
 412         start = hfsplus_block_allocate(sb, sbi->total_blocks, goal, &len);
 413         if (start >= sbi->total_blocks) {
 414                 start = hfsplus_block_allocate(sb, goal, 0, &len);
 415                 if (start >= goal) {
 416                         res = -ENOSPC;
 417                         goto out;
 418                 }
 419         }
 420
 421         dprint(DBG_EXTENT, "extend %lu: %u,%u\n", inode->i_ino, start, len);
 422
 423         if (hip->alloc_blocks <= hip->first_blocks) {
 424                 if (!hip->first_blocks) {
 425                         dprint(DBG_EXTENT, "first extents\n");
 426                         /* no extents yet */
 427                         hip->first_extents[0].start_block = cpu_to_be32(start);
 428                         hip->first_extents[0].block_count = cpu_to_be32(len);
 429                         res = 0;
 430                 } else {
 431                         /* try to append to extents in inode */
 432                         res = hfsplus_add_extent(hip->first_extents,
 433                                                  hip->alloc_blocks,
 434                                                  start, len);
 435                         if (res == -ENOSPC)
 436                                 goto insert_extent;
 437                 }
 438                 if (!res) {
 439                         hfsplus_dump_extent(hip->first_extents);
 440                         hip->first_blocks += len;
 441                 }
 442         } else {
 443                 res = hfsplus_add_extent(hip->cached_extents,
 444                                          hip->alloc_blocks - hip->cached_start,
 445                                          start, len);
 446                 if (!res) {
 447                         hfsplus_dump_extent(hip->cached_extents);
 448                         hip->extent_state |= HFSPLUS_EXT_DIRTY;
 449                         hip->cached_blocks += len;
 450                 } else if (res == -ENOSPC)
 451                         goto insert_extent;
 452         }
 453 out:
 454         mutex_unlock(&hip->extents_lock);
 455         if (!res) {
 456                 hip->alloc_blocks += len;
 457                 hfsplus_mark_inode_dirty(inode, HFSPLUS_I_ALLOC_DIRTY);
 458         }
 459         return res;
 460
 461 insert_extent:
 462         dprint(DBG_EXTENT, "insert new extent\n");
 463         hfsplus_ext_write_extent_locked(inode);
 464
 465         memset(hip->cached_extents, 0, sizeof(hfsplus_extent_rec));
 466         hip->cached_extents[0].start_block = cpu_to_be32(start);
 467         hip->cached_extents[0].block_count = cpu_to_be32(len);
 468         hfsplus_dump_extent(hip->cached_extents);
 469         hip->extent_state |= HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW;
 470         hip->cached_start = hip->alloc_blocks;
 471         hip->cached_blocks = len;
 472
 473         res = 0;
 474         goto out;
 475 }
 476
 477 void hfsplus_file_truncate(struct inode *inode)
 478 {
 479         struct super_block *sb = inode->i_sb;
 480         struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
 481         struct hfs_find_data fd;
 482         u32 alloc_cnt, blk_cnt, start;
 483         int res;
 484
 485         dprint(DBG_INODE, "truncate: %lu, %Lu -> %Lu\n",
 486                 inode->i_ino, (long long)hip->phys_size, inode->i_size);
 487
 488         if (inode->i_size > hip->phys_size) {
 489                 struct address_space *mapping = inode->i_mapping;
 490                 struct page *page;
 491                 void *fsdata;
 492                 u32 size = inode->i_size;
 493                 int res;
 494
 495                 res = pagecache_write_begin(NULL, mapping, size, 0,
 496                                                 AOP_FLAG_UNINTERRUPTIBLE,
 497                                                 &page, &fsdata);
 498                 if (res)
 499                         return;
 500                 res = pagecache_write_end(NULL, mapping, size, 0, 0, page, fsdata);
 501                 if (res < 0)
 502                         return;
 503                 mark_inode_dirty(inode);
 504                 return;
 505         } else if (inode->i_size == hip->phys_size)
 506                 return;
 507
 508         blk_cnt = (inode->i_size + HFSPLUS_SB(sb)->alloc_blksz - 1) >>
 509                         HFSPLUS_SB(sb)->alloc_blksz_shift;
 510         alloc_cnt = hip->alloc_blocks;
 511         if (blk_cnt == alloc_cnt)
 512                 goto out;
 513
 514         mutex_lock(&hip->extents_lock);
 515         hfs_find_init(HFSPLUS_SB(sb)->ext_tree, &fd);
 516         while (1) {
 517                 if (alloc_cnt == hip->first_blocks) {
 518                         hfsplus_free_extents(sb, hip->first_extents,
 519                                              alloc_cnt, alloc_cnt - blk_cnt);
 520                         hfsplus_dump_extent(hip->first_extents);
 521                         hip->first_blocks = blk_cnt;
 522                         break;
 523                 }
 524                 res = __hfsplus_ext_cache_extent(&fd, inode, alloc_cnt);
 525                 if (res)
 526                         break;
 527                 start = hip->cached_start;
 528                 hfsplus_free_extents(sb, hip->cached_extents,
 529                                      alloc_cnt - start, alloc_cnt - blk_cnt);
 530                 hfsplus_dump_extent(hip->cached_extents);
 531                 if (blk_cnt > start) {
 532                         hip->extent_state |= HFSPLUS_EXT_DIRTY;
 533                         break;
 534                 }
 535                 alloc_cnt = start;
 536                 hip->cached_start = hip->cached_blocks = 0;
 537                 hip->extent_state &= ~(HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW);
 538                 hfs_brec_remove(&fd);
 539         }
 540         hfs_find_exit(&fd);
 541         mutex_unlock(&hip->extents_lock);
 542
 543         hip->alloc_blocks = blk_cnt;
 544 out:
 545         hip->phys_size = inode->i_size;
 546         hip->fs_blocks = (inode->i_size + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
 547         inode_set_bytes(inode, hip->fs_blocks << sb->s_blocksize_bits);
 548         hfsplus_mark_inode_dirty(inode, HFSPLUS_I_ALLOC_DIRTY);
 549 }