git.oblomov.eu Git - linux-2.6/blob - 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         if (inode->i_ino == HFSPLUS_EXT_CNID)
 203                 return -EIO;
 204
 205         mutex_lock(&HFSPLUS_I(inode).extents_lock);
 206         res = hfsplus_ext_read_extent(inode, ablock);
 207         if (!res) {
 208                 dblock = hfsplus_ext_find_block(HFSPLUS_I(inode).cached_extents, ablock -
 209                                              HFSPLUS_I(inode).cached_start);
 210         } else {
 211                 mutex_unlock(&HFSPLUS_I(inode).extents_lock);
 212                 return -EIO;
 213         }
 214         mutex_unlock(&HFSPLUS_I(inode).extents_lock);
 215
 216 done:
 217         dprint(DBG_EXTENT, "get_block(%lu): %llu - %u\n", inode->i_ino, (long long)iblock, dblock);
 218         mask = (1 << HFSPLUS_SB(sb).fs_shift) - 1;
 219         map_bh(bh_result, sb, (dblock << HFSPLUS_SB(sb).fs_shift) + HFSPLUS_SB(sb).blockoffset + (iblock & mask));
 220         if (create) {
 221                 set_buffer_new(bh_result);
 222                 HFSPLUS_I(inode).phys_size += sb->s_blocksize;
 223                 HFSPLUS_I(inode).fs_blocks++;
 224                 inode_add_bytes(inode, sb->s_blocksize);
 225                 mark_inode_dirty(inode);
 226         }
 227         return 0;
 228 }
 229
 230 static void hfsplus_dump_extent(struct hfsplus_extent *extent)
 231 {
 232         int i;
 233
 234         dprint(DBG_EXTENT, "   ");
 235         for (i = 0; i < 8; i++)
 236                 dprint(DBG_EXTENT, " %u:%u", be32_to_cpu(extent[i].start_block),
 237                                  be32_to_cpu(extent[i].block_count));
 238         dprint(DBG_EXTENT, "\n");
 239 }
 240
 241 static int hfsplus_add_extent(struct hfsplus_extent *extent, u32 offset,
 242                               u32 alloc_block, u32 block_count)
 243 {
 244         u32 count, start;
 245         int i;
 246
 247         hfsplus_dump_extent(extent);
 248         for (i = 0; i < 8; extent++, i++) {
 249                 count = be32_to_cpu(extent->block_count);
 250                 if (offset == count) {
 251                         start = be32_to_cpu(extent->start_block);
 252                         if (alloc_block != start + count) {
 253                                 if (++i >= 8)
 254                                         return -ENOSPC;
 255                                 extent++;
 256                                 extent->start_block = cpu_to_be32(alloc_block);
 257                         } else
 258                                 block_count += count;
 259                         extent->block_count = cpu_to_be32(block_count);
 260                         return 0;
 261                 } else if (offset < count)
 262                         break;
 263                 offset -= count;
 264         }
 265         /* panic? */
 266         return -EIO;
 267 }
 268
 269 static int hfsplus_free_extents(struct super_block *sb,
 270                                 struct hfsplus_extent *extent,
 271                                 u32 offset, u32 block_nr)
 272 {
 273         u32 count, start;
 274         int i;
 275
 276         hfsplus_dump_extent(extent);
 277         for (i = 0; i < 8; extent++, i++) {
 278                 count = be32_to_cpu(extent->block_count);
 279                 if (offset == count)
 280                         goto found;
 281                 else if (offset < count)
 282                         break;
 283                 offset -= count;
 284         }
 285         /* panic? */
 286         return -EIO;
 287 found:
 288         for (;;) {
 289                 start = be32_to_cpu(extent->start_block);
 290                 if (count <= block_nr) {
 291                         hfsplus_block_free(sb, start, count);
 292                         extent->block_count = 0;
 293                         extent->start_block = 0;
 294                         block_nr -= count;
 295                 } else {
 296                         count -= block_nr;
 297                         hfsplus_block_free(sb, start + count, block_nr);
 298                         extent->block_count = cpu_to_be32(count);
 299                         block_nr = 0;
 300                 }
 301                 if (!block_nr || !i)
 302                         return 0;
 303                 i--;
 304                 extent--;
 305                 count = be32_to_cpu(extent->block_count);
 306         }
 307 }
 308
 309 int hfsplus_free_fork(struct super_block *sb, u32 cnid, struct hfsplus_fork_raw *fork, int type)
 310 {
 311         struct hfs_find_data fd;
 312         hfsplus_extent_rec ext_entry;
 313         u32 total_blocks, blocks, start;
 314         int res, i;
 315
 316         total_blocks = be32_to_cpu(fork->total_blocks);
 317         if (!total_blocks)
 318                 return 0;
 319
 320         blocks = 0;
 321         for (i = 0; i < 8; i++)
 322                 blocks += be32_to_cpu(fork->extents[i].block_count);
 323
 324         res = hfsplus_free_extents(sb, fork->extents, blocks, blocks);
 325         if (res)
 326                 return res;
 327         if (total_blocks == blocks)
 328                 return 0;
 329
 330         hfs_find_init(HFSPLUS_SB(sb).ext_tree, &fd);
 331         do {
 332                 res = __hfsplus_ext_read_extent(&fd, ext_entry, cnid,
 333                                                 total_blocks, type);
 334                 if (res)
 335                         break;
 336                 start = be32_to_cpu(fd.key->ext.start_block);
 337                 hfsplus_free_extents(sb, ext_entry,
 338                                      total_blocks - start,
 339                                      total_blocks);
 340                 hfs_brec_remove(&fd);
 341                 total_blocks = start;
 342         } while (total_blocks > blocks);
 343         hfs_find_exit(&fd);
 344
 345         return res;
 346 }
 347
 348 int hfsplus_file_extend(struct inode *inode)
 349 {
 350         struct super_block *sb = inode->i_sb;
 351         u32 start, len, goal;
 352         int res;
 353
 354         if (HFSPLUS_SB(sb).alloc_file->i_size * 8 < HFSPLUS_SB(sb).total_blocks - HFSPLUS_SB(sb).free_blocks + 8) {
 355                 // extend alloc file
 356                 printk(KERN_ERR "hfs: extend alloc file! (%Lu,%u,%u)\n", HFSPLUS_SB(sb).alloc_file->i_size * 8,
 357                         HFSPLUS_SB(sb).total_blocks, HFSPLUS_SB(sb).free_blocks);
 358                 return -ENOSPC;
 359         }
 360
 361         mutex_lock(&HFSPLUS_I(inode).extents_lock);
 362         if (HFSPLUS_I(inode).alloc_blocks == HFSPLUS_I(inode).first_blocks)
 363                 goal = hfsplus_ext_lastblock(HFSPLUS_I(inode).first_extents);
 364         else {
 365                 res = hfsplus_ext_read_extent(inode, HFSPLUS_I(inode).alloc_blocks);
 366                 if (res)
 367                         goto out;
 368                 goal = hfsplus_ext_lastblock(HFSPLUS_I(inode).cached_extents);
 369         }
 370
 371         len = HFSPLUS_I(inode).clump_blocks;
 372         start = hfsplus_block_allocate(sb, HFSPLUS_SB(sb).total_blocks, goal, &len);
 373         if (start >= HFSPLUS_SB(sb).total_blocks) {
 374                 start = hfsplus_block_allocate(sb, goal, 0, &len);
 375                 if (start >= goal) {
 376                         res = -ENOSPC;
 377                         goto out;
 378                 }
 379         }
 380
 381         dprint(DBG_EXTENT, "extend %lu: %u,%u\n", inode->i_ino, start, len);
 382         if (HFSPLUS_I(inode).alloc_blocks <= HFSPLUS_I(inode).first_blocks) {
 383                 if (!HFSPLUS_I(inode).first_blocks) {
 384                         dprint(DBG_EXTENT, "first extents\n");
 385                         /* no extents yet */
 386                         HFSPLUS_I(inode).first_extents[0].start_block = cpu_to_be32(start);
 387                         HFSPLUS_I(inode).first_extents[0].block_count = cpu_to_be32(len);
 388                         res = 0;
 389                 } else {
 390                         /* try to append to extents in inode */
 391                         res = hfsplus_add_extent(HFSPLUS_I(inode).first_extents,
 392                                                  HFSPLUS_I(inode).alloc_blocks,
 393                                                  start, len);
 394                         if (res == -ENOSPC)
 395                                 goto insert_extent;
 396                 }
 397                 if (!res) {
 398                         hfsplus_dump_extent(HFSPLUS_I(inode).first_extents);
 399                         HFSPLUS_I(inode).first_blocks += len;
 400                 }
 401         } else {
 402                 res = hfsplus_add_extent(HFSPLUS_I(inode).cached_extents,
 403                                          HFSPLUS_I(inode).alloc_blocks -
 404                                          HFSPLUS_I(inode).cached_start,
 405                                          start, len);
 406                 if (!res) {
 407                         hfsplus_dump_extent(HFSPLUS_I(inode).cached_extents);
 408                         HFSPLUS_I(inode).flags |= HFSPLUS_FLG_EXT_DIRTY;
 409                         HFSPLUS_I(inode).cached_blocks += len;
 410                 } else if (res == -ENOSPC)
 411                         goto insert_extent;
 412         }
 413 out:
 414         mutex_unlock(&HFSPLUS_I(inode).extents_lock);
 415         if (!res) {
 416                 HFSPLUS_I(inode).alloc_blocks += len;
 417                 mark_inode_dirty(inode);
 418         }
 419         return res;
 420
 421 insert_extent:
 422         dprint(DBG_EXTENT, "insert new extent\n");
 423         hfsplus_ext_write_extent(inode);
 424
 425         memset(HFSPLUS_I(inode).cached_extents, 0, sizeof(hfsplus_extent_rec));
 426         HFSPLUS_I(inode).cached_extents[0].start_block = cpu_to_be32(start);
 427         HFSPLUS_I(inode).cached_extents[0].block_count = cpu_to_be32(len);
 428         hfsplus_dump_extent(HFSPLUS_I(inode).cached_extents);
 429         HFSPLUS_I(inode).flags |= HFSPLUS_FLG_EXT_DIRTY | HFSPLUS_FLG_EXT_NEW;
 430         HFSPLUS_I(inode).cached_start = HFSPLUS_I(inode).alloc_blocks;
 431         HFSPLUS_I(inode).cached_blocks = len;
 432
 433         res = 0;
 434         goto out;
 435 }
 436
 437 void hfsplus_file_truncate(struct inode *inode)
 438 {
 439         struct super_block *sb = inode->i_sb;
 440         struct hfs_find_data fd;
 441         u32 alloc_cnt, blk_cnt, start;
 442         int res;
 443
 444         dprint(DBG_INODE, "truncate: %lu, %Lu -> %Lu\n", inode->i_ino,
 445                (long long)HFSPLUS_I(inode).phys_size, inode->i_size);
 446         if (inode->i_size > HFSPLUS_I(inode).phys_size) {
 447                 struct address_space *mapping = inode->i_mapping;
 448                 struct page *page;
 449                 void *fsdata;
 450                 u32 size = inode->i_size;
 451                 int res;
 452
 453                 res = pagecache_write_begin(NULL, mapping, size, 0,
 454                                                 AOP_FLAG_UNINTERRUPTIBLE,
 455                                                 &page, &fsdata);
 456                 if (res)
 457                         return;
 458                 res = pagecache_write_end(NULL, mapping, size, 0, 0, page, fsdata);
 459                 if (res < 0)
 460                         return;
 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         mutex_lock(&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         mutex_unlock(&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 }