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