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