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(hfsplus_btree_key *k1, hfsplus_btree_key *k2)
  20 {
  21         __be32 k1id, k2id;
  22         __be32 k1s, k2s;
  23
  24         k1id = k1->ext.cnid;
  25         k2id = k2->ext.cnid;
  26         if (k1id != k2id)
  27                 return be32_to_cpu(k1id) < be32_to_cpu(k2id) ? -1 : 1;
  28
  29         if (k1->ext.fork_type != k2->ext.fork_type)
  30                 return k1->ext.fork_type < k2->ext.fork_type ? -1 : 1;
  31
  32         k1s = k1->ext.start_block;
  33         k2s = k2->ext.start_block;
  34         if (k1s == k2s)
  35                 return 0;
  36         return be32_to_cpu(k1s) < be32_to_cpu(k2s) ? -1 : 1;
  37 }
  38
  39 static void hfsplus_ext_build_key(hfsplus_btree_key *key, u32 cnid,
  40                                   u32 block, u8 type)
  41 {
  42         key->key_len = cpu_to_be16(HFSPLUS_EXT_KEYLEN - 2);
  43         key->ext.cnid = cpu_to_be32(cnid);
  44         key->ext.start_block = cpu_to_be32(block);
  45         key->ext.fork_type = type;
  46         key->ext.pad = 0;
  47 }
  48
  49 static u32 hfsplus_ext_find_block(struct hfsplus_extent *ext, u32 off)
  50 {
  51         int i;
  52         u32 count;
  53
  54         for (i = 0; i < 8; ext++, i++) {
  55                 count = be32_to_cpu(ext->block_count);
  56                 if (off < count)
  57                         return be32_to_cpu(ext->start_block) + off;
  58                 off -= count;
  59         }
  60         /* panic? */
  61         return 0;
  62 }
  63
  64 static int hfsplus_ext_block_count(struct hfsplus_extent *ext)
  65 {
  66         int i;
  67         u32 count = 0;
  68
  69         for (i = 0; i < 8; ext++, i++)
  70                 count += be32_to_cpu(ext->block_count);
  71         return count;
  72 }
  73
  74 static u32 hfsplus_ext_lastblock(struct hfsplus_extent *ext)
  75 {
  76         int i;
  77
  78         ext += 7;
  79         for (i = 0; i < 7; ext--, i++)
  80                 if (ext->block_count)
  81                         break;
  82         return be32_to_cpu(ext->start_block) + be32_to_cpu(ext->block_count);
  83 }
  84
  85 static void __hfsplus_ext_write_extent(struct inode *inode, struct hfs_find_data *fd)
  86 {
  87         int res;
  88
  89         hfsplus_ext_build_key(fd->search_key, inode->i_ino, HFSPLUS_I(inode).cached_start,
  90                               HFSPLUS_IS_RSRC(inode) ?  HFSPLUS_TYPE_RSRC : HFSPLUS_TYPE_DATA);
  91         res = hfs_brec_find(fd);
  92         if (HFSPLUS_I(inode).flags & HFSPLUS_FLG_EXT_NEW) {
  93                 if (res != -ENOENT)
  94                         return;
  95                 hfs_brec_insert(fd, HFSPLUS_I(inode).cached_extents, sizeof(hfsplus_extent_rec));
  96                 HFSPLUS_I(inode).flags &= ~(HFSPLUS_FLG_EXT_DIRTY | HFSPLUS_FLG_EXT_NEW);
  97         } else {
  98                 if (res)
  99                         return;
 100                 hfs_bnode_write(fd->bnode, HFSPLUS_I(inode).cached_extents, fd->entryoffset, fd->entrylength);
 101                 HFSPLUS_I(inode).flags &= ~HFSPLUS_FLG_EXT_DIRTY;
 102         }
 103 }
 104
 105 void hfsplus_ext_write_extent(struct inode *inode)
 106 {
 107         if (HFSPLUS_I(inode).flags & HFSPLUS_FLG_EXT_DIRTY) {
 108                 struct hfs_find_data fd;
 109
 110                 hfs_find_init(HFSPLUS_SB(inode->i_sb).ext_tree, &fd);
 111                 __hfsplus_ext_write_extent(inode, &fd);
 112                 hfs_find_exit(&fd);
 113         }
 114 }
 115
 116 static inline int __hfsplus_ext_read_extent(struct hfs_find_data *fd,
 117                                             struct hfsplus_extent *extent,
 118                                             u32 cnid, u32 block, u8 type)
 119 {
 120         int res;
 121
 122         hfsplus_ext_build_key(fd->search_key, cnid, block, type);
 123         fd->key->ext.cnid = 0;
 124         res = hfs_brec_find(fd);
 125         if (res && res != -ENOENT)
 126                 return res;
 127         if (fd->key->ext.cnid != fd->search_key->ext.cnid ||
 128             fd->key->ext.fork_type != fd->search_key->ext.fork_type)
 129                 return -ENOENT;
 130         if (fd->entrylength != sizeof(hfsplus_extent_rec))
 131                 return -EIO;
 132         hfs_bnode_read(fd->bnode, extent, fd->entryoffset, sizeof(hfsplus_extent_rec));
 133         return 0;
 134 }
 135
 136 static inline int __hfsplus_ext_cache_extent(struct hfs_find_data *fd, struct inode *inode, u32 block)
 137 {
 138         int res;
 139
 140         if (HFSPLUS_I(inode).flags & HFSPLUS_FLG_EXT_DIRTY)
 141                 __hfsplus_ext_write_extent(inode, fd);
 142
 143         res = __hfsplus_ext_read_extent(fd, HFSPLUS_I(inode).cached_extents, inode->i_ino,
 144                                         block, HFSPLUS_IS_RSRC(inode) ? HFSPLUS_TYPE_RSRC : HFSPLUS_TYPE_DATA);
 145         if (!res) {
 146                 HFSPLUS_I(inode).cached_start = be32_to_cpu(fd->key->ext.start_block);
 147                 HFSPLUS_I(inode).cached_blocks = hfsplus_ext_block_count(HFSPLUS_I(inode).cached_extents);
 148         } else {
 149                 HFSPLUS_I(inode).cached_start = HFSPLUS_I(inode).cached_blocks = 0;
 150                 HFSPLUS_I(inode).flags &= ~(HFSPLUS_FLG_EXT_DIRTY | HFSPLUS_FLG_EXT_NEW);
 151         }
 152         return res;
 153 }
 154
 155 static int hfsplus_ext_read_extent(struct inode *inode, u32 block)
 156 {
 157         struct hfs_find_data fd;
 158         int res;
 159
 160         if (block >= HFSPLUS_I(inode).cached_start &&
 161             block < HFSPLUS_I(inode).cached_start + HFSPLUS_I(inode).cached_blocks)
 162                 return 0;
 163
 164         hfs_find_init(HFSPLUS_SB(inode->i_sb).ext_tree, &fd);
 165         res = __hfsplus_ext_cache_extent(&fd, inode, block);
 166         hfs_find_exit(&fd);
 167         return res;
 168 }
 169
 170 /* Get a block at iblock for inode, possibly allocating if create */
 171 int hfsplus_get_block(struct inode *inode, sector_t iblock,
 172                       struct buffer_head *bh_result, int create)
 173 {
 174         struct super_block *sb;
 175         int res = -EIO;
 176         u32 ablock, dblock, mask;
 177         int shift;
 178
 179         sb = inode->i_sb;
 180
 181         /* Convert inode block to disk allocation block */
 182         shift = HFSPLUS_SB(sb).alloc_blksz_shift - sb->s_blocksize_bits;
 183         ablock = iblock >> HFSPLUS_SB(sb).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         down(&HFSPLUS_I(inode).extents_lock);
 202         res = hfsplus_ext_read_extent(inode, ablock);
 203         if (!res) {
 204                 dblock = hfsplus_ext_find_block(HFSPLUS_I(inode).cached_extents, ablock -
 205                                              HFSPLUS_I(inode).cached_start);
 206         } else {
 207                 up(&HFSPLUS_I(inode).extents_lock);
 208                 return -EIO;
 209         }
 210         up(&HFSPLUS_I(inode).extents_lock);
 211
 212 done:
 213         dprint(DBG_EXTENT, "get_block(%lu): %llu - %u\n", inode->i_ino, (long long)iblock, dblock);
 214         mask = (1 << HFSPLUS_SB(sb).fs_shift) - 1;
 215         map_bh(bh_result, sb, (dblock << HFSPLUS_SB(sb).fs_shift) + HFSPLUS_SB(sb).blockoffset + (iblock & mask));
 216         if (create) {
 217                 set_buffer_new(bh_result);
 218                 HFSPLUS_I(inode).phys_size += sb->s_blocksize;
 219                 HFSPLUS_I(inode).fs_blocks++;
 220                 inode_add_bytes(inode, sb->s_blocksize);
 221                 mark_inode_dirty(inode);
 222         }
 223         return 0;
 224 }
 225
 226 static void hfsplus_dump_extent(struct hfsplus_extent *extent)
 227 {
 228         int i;
 229
 230         dprint(DBG_EXTENT, "   ");
 231         for (i = 0; i < 8; i++)
 232                 dprint(DBG_EXTENT, " %u:%u", be32_to_cpu(extent[i].start_block),
 233                                  be32_to_cpu(extent[i].block_count));
 234         dprint(DBG_EXTENT, "\n");
 235 }
 236
 237 static int hfsplus_add_extent(struct hfsplus_extent *extent, u32 offset,
 238                               u32 alloc_block, u32 block_count)
 239 {
 240         u32 count, start;
 241         int i;
 242
 243         hfsplus_dump_extent(extent);
 244         for (i = 0; i < 8; extent++, i++) {
 245                 count = be32_to_cpu(extent->block_count);
 246                 if (offset == count) {
 247                         start = be32_to_cpu(extent->start_block);
 248                         if (alloc_block != start + count) {
 249                                 if (++i >= 8)
 250                                         return -ENOSPC;
 251                                 extent++;
 252                                 extent->start_block = cpu_to_be32(alloc_block);
 253                         } else
 254                                 block_count += count;
 255                         extent->block_count = cpu_to_be32(block_count);
 256                         return 0;
 257                 } else if (offset < count)
 258                         break;
 259                 offset -= count;
 260         }
 261         /* panic? */
 262         return -EIO;
 263 }
 264
 265 static int hfsplus_free_extents(struct super_block *sb,
 266                                 struct hfsplus_extent *extent,
 267                                 u32 offset, u32 block_nr)
 268 {
 269         u32 count, start;
 270         int i;
 271
 272         hfsplus_dump_extent(extent);
 273         for (i = 0; i < 8; extent++, i++) {
 274                 count = be32_to_cpu(extent->block_count);
 275                 if (offset == count)
 276                         goto found;
 277                 else if (offset < count)
 278                         break;
 279                 offset -= count;
 280         }
 281         /* panic? */
 282         return -EIO;
 283 found:
 284         for (;;) {
 285                 start = be32_to_cpu(extent->start_block);
 286                 if (count <= block_nr) {
 287                         hfsplus_block_free(sb, start, count);
 288                         extent->block_count = 0;
 289                         extent->start_block = 0;
 290                         block_nr -= count;
 291                 } else {
 292                         count -= block_nr;
 293                         hfsplus_block_free(sb, start + count, block_nr);
 294                         extent->block_count = cpu_to_be32(count);
 295                         block_nr = 0;
 296                 }
 297                 if (!block_nr || !i)
 298                         return 0;
 299                 i--;
 300                 extent--;
 301                 count = be32_to_cpu(extent->block_count);
 302         }
 303 }
 304
 305 int hfsplus_free_fork(struct super_block *sb, u32 cnid, struct hfsplus_fork_raw *fork, int type)
 306 {
 307         struct hfs_find_data fd;
 308         hfsplus_extent_rec ext_entry;
 309         u32 total_blocks, blocks, start;
 310         int res, i;
 311
 312         total_blocks = be32_to_cpu(fork->total_blocks);
 313         if (!total_blocks)
 314                 return 0;
 315
 316         blocks = 0;
 317         for (i = 0; i < 8; i++)
 318                 blocks += be32_to_cpu(fork->extents[i].block_count);
 319
 320         res = hfsplus_free_extents(sb, fork->extents, blocks, blocks);
 321         if (res)
 322                 return res;
 323         if (total_blocks == blocks)
 324                 return 0;
 325
 326         hfs_find_init(HFSPLUS_SB(sb).ext_tree, &fd);
 327         do {
 328                 res = __hfsplus_ext_read_extent(&fd, ext_entry, cnid,
 329                                                 total_blocks, type);
 330                 if (res)
 331                         break;
 332                 start = be32_to_cpu(fd.key->ext.start_block);
 333                 hfsplus_free_extents(sb, ext_entry,
 334                                      total_blocks - start,
 335                                      total_blocks);
 336                 hfs_brec_remove(&fd);
 337                 total_blocks = start;
 338         } while (total_blocks > blocks);
 339         hfs_find_exit(&fd);
 340
 341         return res;
 342 }
 343
 344 int hfsplus_file_extend(struct inode *inode)
 345 {
 346         struct super_block *sb = inode->i_sb;
 347         u32 start, len, goal;
 348         int res;
 349
 350         if (HFSPLUS_SB(sb).alloc_file->i_size * 8 < HFSPLUS_SB(sb).total_blocks - HFSPLUS_SB(sb).free_blocks + 8) {
 351                 // extend alloc file
 352                 printk("extend alloc file! (%Lu,%u,%u)\n", HFSPLUS_SB(sb).alloc_file->i_size * 8,
 353                         HFSPLUS_SB(sb).total_blocks, HFSPLUS_SB(sb).free_blocks);
 354                 return -ENOSPC;
 355                 //BUG();
 356         }
 357
 358         down(&HFSPLUS_I(inode).extents_lock);
 359         if (HFSPLUS_I(inode).alloc_blocks == HFSPLUS_I(inode).first_blocks)
 360                 goal = hfsplus_ext_lastblock(HFSPLUS_I(inode).first_extents);
 361         else {
 362                 res = hfsplus_ext_read_extent(inode, HFSPLUS_I(inode).alloc_blocks);
 363                 if (res)
 364                         goto out;
 365                 goal = hfsplus_ext_lastblock(HFSPLUS_I(inode).cached_extents);
 366         }
 367
 368         len = HFSPLUS_I(inode).clump_blocks;
 369         start = hfsplus_block_allocate(sb, HFSPLUS_SB(sb).total_blocks, goal, &len);
 370         if (start >= HFSPLUS_SB(sb).total_blocks) {
 371                 start = hfsplus_block_allocate(sb, goal, 0, &len);
 372                 if (start >= goal) {
 373                         res = -ENOSPC;
 374                         goto out;
 375                 }
 376         }
 377
 378         dprint(DBG_EXTENT, "extend %lu: %u,%u\n", inode->i_ino, start, len);
 379         if (HFSPLUS_I(inode).alloc_blocks <= HFSPLUS_I(inode).first_blocks) {
 380                 if (!HFSPLUS_I(inode).first_blocks) {
 381                         dprint(DBG_EXTENT, "first extents\n");
 382                         /* no extents yet */
 383                         HFSPLUS_I(inode).first_extents[0].start_block = cpu_to_be32(start);
 384                         HFSPLUS_I(inode).first_extents[0].block_count = cpu_to_be32(len);
 385                         res = 0;
 386                 } else {
 387                         /* try to append to extents in inode */
 388                         res = hfsplus_add_extent(HFSPLUS_I(inode).first_extents,
 389                                                  HFSPLUS_I(inode).alloc_blocks,
 390                                                  start, len);
 391                         if (res == -ENOSPC)
 392                                 goto insert_extent;
 393                 }
 394                 if (!res) {
 395                         hfsplus_dump_extent(HFSPLUS_I(inode).first_extents);
 396                         HFSPLUS_I(inode).first_blocks += len;
 397                 }
 398         } else {
 399                 res = hfsplus_add_extent(HFSPLUS_I(inode).cached_extents,
 400                                          HFSPLUS_I(inode).alloc_blocks -
 401                                          HFSPLUS_I(inode).cached_start,
 402                                          start, len);
 403                 if (!res) {
 404                         hfsplus_dump_extent(HFSPLUS_I(inode).cached_extents);
 405                         HFSPLUS_I(inode).flags |= HFSPLUS_FLG_EXT_DIRTY;
 406                         HFSPLUS_I(inode).cached_blocks += len;
 407                 } else if (res == -ENOSPC)
 408                         goto insert_extent;
 409         }
 410 out:
 411         up(&HFSPLUS_I(inode).extents_lock);
 412         if (!res) {
 413                 HFSPLUS_I(inode).alloc_blocks += len;
 414                 mark_inode_dirty(inode);
 415         }
 416         return res;
 417
 418 insert_extent:
 419         dprint(DBG_EXTENT, "insert new extent\n");
 420         hfsplus_ext_write_extent(inode);
 421
 422         memset(HFSPLUS_I(inode).cached_extents, 0, sizeof(hfsplus_extent_rec));
 423         HFSPLUS_I(inode).cached_extents[0].start_block = cpu_to_be32(start);
 424         HFSPLUS_I(inode).cached_extents[0].block_count = cpu_to_be32(len);
 425         hfsplus_dump_extent(HFSPLUS_I(inode).cached_extents);
 426         HFSPLUS_I(inode).flags |= HFSPLUS_FLG_EXT_DIRTY | HFSPLUS_FLG_EXT_NEW;
 427         HFSPLUS_I(inode).cached_start = HFSPLUS_I(inode).alloc_blocks;
 428         HFSPLUS_I(inode).cached_blocks = len;
 429
 430         res = 0;
 431         goto out;
 432 }
 433
 434 void hfsplus_file_truncate(struct inode *inode)
 435 {
 436         struct super_block *sb = inode->i_sb;
 437         struct hfs_find_data fd;
 438         u32 alloc_cnt, blk_cnt, start;
 439         int res;
 440
 441         dprint(DBG_INODE, "truncate: %lu, %Lu -> %Lu\n", inode->i_ino,
 442                (long long)HFSPLUS_I(inode).phys_size, inode->i_size);
 443         if (inode->i_size > HFSPLUS_I(inode).phys_size) {
 444                 struct address_space *mapping = inode->i_mapping;
 445                 struct page *page;
 446                 u32 size = inode->i_size - 1;
 447                 int res;
 448
 449                 page = grab_cache_page(mapping, size >> PAGE_CACHE_SHIFT);
 450                 if (!page)
 451                         return;
 452                 size &= PAGE_CACHE_SIZE - 1;
 453                 size++;
 454                 res = mapping->a_ops->prepare_write(NULL, page, size, size);
 455                 if (!res)
 456                         res = mapping->a_ops->commit_write(NULL, page, size, size);
 457                 if (res)
 458                         inode->i_size = HFSPLUS_I(inode).phys_size;
 459                 unlock_page(page);
 460                 page_cache_release(page);
 461                 mark_inode_dirty(inode);
 462                 return;
 463         } else if (inode->i_size == HFSPLUS_I(inode).phys_size)
 464                 return;
 465
 466         blk_cnt = (inode->i_size + HFSPLUS_SB(sb).alloc_blksz - 1) >> HFSPLUS_SB(sb).alloc_blksz_shift;
 467         alloc_cnt = HFSPLUS_I(inode).alloc_blocks;
 468         if (blk_cnt == alloc_cnt)
 469                 goto out;
 470
 471         down(&HFSPLUS_I(inode).extents_lock);
 472         hfs_find_init(HFSPLUS_SB(sb).ext_tree, &fd);
 473         while (1) {
 474                 if (alloc_cnt == HFSPLUS_I(inode).first_blocks) {
 475                         hfsplus_free_extents(sb, HFSPLUS_I(inode).first_extents,
 476                                              alloc_cnt, alloc_cnt - blk_cnt);
 477                         hfsplus_dump_extent(HFSPLUS_I(inode).first_extents);
 478                         HFSPLUS_I(inode).first_blocks = blk_cnt;
 479                         break;
 480                 }
 481                 res = __hfsplus_ext_cache_extent(&fd, inode, alloc_cnt);
 482                 if (res)
 483                         break;
 484                 start = HFSPLUS_I(inode).cached_start;
 485                 hfsplus_free_extents(sb, HFSPLUS_I(inode).cached_extents,
 486                                      alloc_cnt - start, alloc_cnt - blk_cnt);
 487                 hfsplus_dump_extent(HFSPLUS_I(inode).cached_extents);
 488                 if (blk_cnt > start) {
 489                         HFSPLUS_I(inode).flags |= HFSPLUS_FLG_EXT_DIRTY;
 490                         break;
 491                 }
 492                 alloc_cnt = start;
 493                 HFSPLUS_I(inode).cached_start = HFSPLUS_I(inode).cached_blocks = 0;
 494                 HFSPLUS_I(inode).flags &= ~(HFSPLUS_FLG_EXT_DIRTY | HFSPLUS_FLG_EXT_NEW);
 495                 hfs_brec_remove(&fd);
 496         }
 497         hfs_find_exit(&fd);
 498         up(&HFSPLUS_I(inode).extents_lock);
 499
 500         HFSPLUS_I(inode).alloc_blocks = blk_cnt;
 501 out:
 502         HFSPLUS_I(inode).phys_size = inode->i_size;
 503         HFSPLUS_I(inode).fs_blocks = (inode->i_size + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
 504         inode_set_bytes(inode, HFSPLUS_I(inode).fs_blocks << sb->s_blocksize_bits);
 505         mark_inode_dirty(inode);
 506 }