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;
 176         int res = -EIO;
 177         u32 ablock, dblock, mask;
 178         int shift;
 179
 180         sb = inode->i_sb;
 181
 182         /* Convert inode block to disk allocation block */
 183         shift = HFSPLUS_SB(sb).alloc_blksz_shift - sb->s_blocksize_bits;
 184         ablock = iblock >> HFSPLUS_SB(sb).fs_shift;
 185
 186         if (iblock >= HFSPLUS_I(inode).fs_blocks) {
 187                 if (iblock > HFSPLUS_I(inode).fs_blocks || !create)
 188                         return -EIO;
 189                 if (ablock >= HFSPLUS_I(inode).alloc_blocks) {
 190                         res = hfsplus_file_extend(inode);
 191                         if (res)
 192                                 return res;
 193                 }
 194         } else
 195                 create = 0;
 196
 197         if (ablock < HFSPLUS_I(inode).first_blocks) {
 198                 dblock = hfsplus_ext_find_block(HFSPLUS_I(inode).first_extents, ablock);
 199                 goto done;
 200         }
 201
 202         down(&HFSPLUS_I(inode).extents_lock);
 203         res = hfsplus_ext_read_extent(inode, ablock);
 204         if (!res) {
 205                 dblock = hfsplus_ext_find_block(HFSPLUS_I(inode).cached_extents, ablock -
 206                                              HFSPLUS_I(inode).cached_start);
 207         } else {
 208                 up(&HFSPLUS_I(inode).extents_lock);
 209                 return -EIO;
 210         }
 211         up(&HFSPLUS_I(inode).extents_lock);
 212
 213 done:
 214         dprint(DBG_EXTENT, "get_block(%lu): %llu - %u\n", inode->i_ino, (long long)iblock, dblock);
 215         mask = (1 << HFSPLUS_SB(sb).fs_shift) - 1;
 216         map_bh(bh_result, sb, (dblock << HFSPLUS_SB(sb).fs_shift) + HFSPLUS_SB(sb).blockoffset + (iblock & mask));
 217         if (create) {
 218                 set_buffer_new(bh_result);
 219                 HFSPLUS_I(inode).phys_size += sb->s_blocksize;
 220                 HFSPLUS_I(inode).fs_blocks++;
 221                 inode_add_bytes(inode, sb->s_blocksize);
 222                 mark_inode_dirty(inode);
 223         }
 224         return 0;
 225 }
 226
 227 static void hfsplus_dump_extent(struct hfsplus_extent *extent)
 228 {
 229         int i;
 230
 231         dprint(DBG_EXTENT, "   ");
 232         for (i = 0; i < 8; i++)
 233                 dprint(DBG_EXTENT, " %u:%u", be32_to_cpu(extent[i].start_block),
 234                                  be32_to_cpu(extent[i].block_count));
 235         dprint(DBG_EXTENT, "\n");
 236 }
 237
 238 static int hfsplus_add_extent(struct hfsplus_extent *extent, u32 offset,
 239                               u32 alloc_block, u32 block_count)
 240 {
 241         u32 count, start;
 242         int i;
 243
 244         hfsplus_dump_extent(extent);
 245         for (i = 0; i < 8; extent++, i++) {
 246                 count = be32_to_cpu(extent->block_count);
 247                 if (offset == count) {
 248                         start = be32_to_cpu(extent->start_block);
 249                         if (alloc_block != start + count) {
 250                                 if (++i >= 8)
 251                                         return -ENOSPC;
 252                                 extent++;
 253                                 extent->start_block = cpu_to_be32(alloc_block);
 254                         } else
 255                                 block_count += count;
 256                         extent->block_count = cpu_to_be32(block_count);
 257                         return 0;
 258                 } else if (offset < count)
 259                         break;
 260                 offset -= count;
 261         }
 262         /* panic? */
 263         return -EIO;
 264 }
 265
 266 static int hfsplus_free_extents(struct super_block *sb,
 267                                 struct hfsplus_extent *extent,
 268                                 u32 offset, u32 block_nr)
 269 {
 270         u32 count, start;
 271         int i;
 272
 273         hfsplus_dump_extent(extent);
 274         for (i = 0; i < 8; extent++, i++) {
 275                 count = be32_to_cpu(extent->block_count);
 276                 if (offset == count)
 277                         goto found;
 278                 else if (offset < count)
 279                         break;
 280                 offset -= count;
 281         }
 282         /* panic? */
 283         return -EIO;
 284 found:
 285         for (;;) {
 286                 start = be32_to_cpu(extent->start_block);
 287                 if (count <= block_nr) {
 288                         hfsplus_block_free(sb, start, count);
 289                         extent->block_count = 0;
 290                         extent->start_block = 0;
 291                         block_nr -= count;
 292                 } else {
 293                         count -= block_nr;
 294                         hfsplus_block_free(sb, start + count, block_nr);
 295                         extent->block_count = cpu_to_be32(count);
 296                         block_nr = 0;
 297                 }
 298                 if (!block_nr || !i)
 299                         return 0;
 300                 i--;
 301                 extent--;
 302                 count = be32_to_cpu(extent->block_count);
 303         }
 304 }
 305
 306 int hfsplus_free_fork(struct super_block *sb, u32 cnid, struct hfsplus_fork_raw *fork, int type)
 307 {
 308         struct hfs_find_data fd;
 309         hfsplus_extent_rec ext_entry;
 310         u32 total_blocks, blocks, start;
 311         int res, i;
 312
 313         total_blocks = be32_to_cpu(fork->total_blocks);
 314         if (!total_blocks)
 315                 return 0;
 316
 317         blocks = 0;
 318         for (i = 0; i < 8; i++)
 319                 blocks += be32_to_cpu(fork->extents[i].block_count);
 320
 321         res = hfsplus_free_extents(sb, fork->extents, blocks, blocks);
 322         if (res)
 323                 return res;
 324         if (total_blocks == blocks)
 325                 return 0;
 326
 327         hfs_find_init(HFSPLUS_SB(sb).ext_tree, &fd);
 328         do {
 329                 res = __hfsplus_ext_read_extent(&fd, ext_entry, cnid,
 330                                                 total_blocks, type);
 331                 if (res)
 332                         break;
 333                 start = be32_to_cpu(fd.key->ext.start_block);
 334                 hfsplus_free_extents(sb, ext_entry,
 335                                      total_blocks - start,
 336                                      total_blocks);
 337                 hfs_brec_remove(&fd);
 338                 total_blocks = start;
 339         } while (total_blocks > blocks);
 340         hfs_find_exit(&fd);
 341
 342         return res;
 343 }
 344
 345 int hfsplus_file_extend(struct inode *inode)
 346 {
 347         struct super_block *sb = inode->i_sb;
 348         u32 start, len, goal;
 349         int res;
 350
 351         if (HFSPLUS_SB(sb).alloc_file->i_size * 8 < HFSPLUS_SB(sb).total_blocks - HFSPLUS_SB(sb).free_blocks + 8) {
 352                 // extend alloc file
 353                 printk(KERN_ERR "hfs: extend alloc file! (%Lu,%u,%u)\n", HFSPLUS_SB(sb).alloc_file->i_size * 8,
 354                         HFSPLUS_SB(sb).total_blocks, HFSPLUS_SB(sb).free_blocks);
 355                 return -ENOSPC;
 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 }