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 #include <linux/version.h>
  15 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,5,0)
  16 #include <linux/buffer_head.h>
  17 #endif
  18
  19 #include "hfsplus_fs.h"
  20 #include "hfsplus_raw.h"
  21
  22 /* Compare two extents keys, returns 0 on same, pos/neg for difference */
  23 int hfsplus_cmp_ext_key(hfsplus_btree_key *k1, hfsplus_btree_key *k2)
  24 {
  25         u32 k1id, k2id;
  26         u32 k1s, k2s;
  27
  28         k1id = k1->ext.cnid;
  29         k2id = k2->ext.cnid;
  30         if (k1id != k2id)
  31                 return be32_to_cpu(k1id) < be32_to_cpu(k2id) ? -1 : 1;
  32
  33         if (k1->ext.fork_type != k2->ext.fork_type)
  34                 return k1->ext.fork_type < k2->ext.fork_type ? -1 : 1;
  35
  36         k1s = k1->ext.start_block;
  37         k2s = k2->ext.start_block;
  38         if (k1s == k2s)
  39                 return 0;
  40         return be32_to_cpu(k1s) < be32_to_cpu(k2s) ? -1 : 1;
  41 }
  42
  43 void hfsplus_fill_ext_key(hfsplus_btree_key *key, u32 cnid,
  44                           u32 block, u8 type)
  45 {
  46         key->key_len = cpu_to_be16(HFSPLUS_EXT_KEYLEN - 2);
  47         key->ext.cnid = cpu_to_be32(cnid);
  48         key->ext.start_block = cpu_to_be32(block);
  49         key->ext.fork_type = type;
  50         key->ext.pad = 0;
  51 }
  52
  53 static u32 hfsplus_find_extent(hfsplus_extent *extent, u32 off)
  54 {
  55         int i;
  56         u32 count;
  57
  58         for (i = 0; i < 8; extent++, i++) {
  59                 count = be32_to_cpu(extent->block_count);
  60                 if (off < count)
  61                         return be32_to_cpu(extent->start_block) + off;
  62                 off -= count;
  63         }
  64         /* panic? */
  65         return 0;
  66 }
  67
  68 static int hfsplus_find_extentry(struct hfsplus_find_data *fd,
  69                                  hfsplus_extent *extent)
  70 {
  71         int res;
  72
  73         fd->key->ext.cnid = 0;
  74         res = hfsplus_btree_find(fd);
  75         if (res && res != -ENOENT)
  76                 return res;
  77         if (fd->key->ext.cnid != fd->search_key->ext.cnid ||
  78             fd->key->ext.fork_type != fd->search_key->ext.fork_type)
  79                 return -ENOENT;
  80         //if (fd->entrylength != ext_key_size)...
  81         hfsplus_bnode_readbytes(fd->bnode, extent, fd->entryoffset, fd->entrylength);
  82         return 0;
  83 }
  84
  85 /* Get a block at iblock for inode, possibly allocating if create */
  86 int hfsplus_get_block(struct inode *inode, sector_t iblock,
  87                       struct buffer_head *bh_result, int create)
  88 {
  89         struct super_block *sb;
  90         hfsplus_extent_rec ext_entry;
  91         struct hfsplus_find_data fd;
  92         int err = -EIO;
  93         u32 ablock, dblock = 0;
  94
  95         sb = inode->i_sb;
  96
  97         /* Convert inode block to disk allocation block */
  98         ablock = iblock;
  99
 100         if (ablock >= HFSPLUS_I(inode).total_blocks) {
 101                 if (ablock > HFSPLUS_I(inode).total_blocks || !create)
 102                         return -EIO;
 103                 if (ablock >= HFSPLUS_I(inode).alloc_blocks) {
 104                         err = hfsplus_extend_file(inode);
 105                         if (err)
 106                                 return err;
 107                 }
 108                 HFSPLUS_I(inode).mmu_private += sb->s_blocksize;
 109                 HFSPLUS_I(inode).total_blocks++;
 110                 mark_inode_dirty(inode);
 111         } else
 112                 create = 0;
 113
 114         if (ablock < HFSPLUS_I(inode).extent_blocks) {
 115                 dblock = hfsplus_find_extent(HFSPLUS_I(inode).extents, ablock);
 116         } else {
 117                 hfsplus_find_init(HFSPLUS_SB(sb).ext_tree, &fd);
 118                 hfsplus_fill_ext_key(fd.search_key, inode->i_ino, ablock, HFSPLUS_IS_RSRC(inode) ?
 119                                      HFSPLUS_TYPE_RSRC : HFSPLUS_TYPE_DATA);
 120                 err = hfsplus_find_extentry(&fd, ext_entry);
 121                 if (!err)
 122                         dblock = hfsplus_find_extent(ext_entry, ablock -
 123                                                     be32_to_cpu(fd.key->ext.start_block));
 124                 hfsplus_find_exit(&fd);
 125                 if (err)
 126                         return err;
 127         }
 128
 129         if (!dblock)
 130                 return -EIO;
 131         dprint(DBG_EXTENT, "get_block(%lu): %lu - %u\n", inode->i_ino, iblock, dblock);
 132
 133         map_bh(bh_result, sb, dblock + HFSPLUS_SB(sb).blockoffset);
 134         if (create)
 135                 set_buffer_new(bh_result);
 136         return 0;
 137 }
 138
 139 static void hfsplus_dump_extent(hfsplus_extent *extent)
 140 {
 141         int i;
 142
 143         dprint(DBG_EXTENT, "   ");
 144         for (i = 0; i < 8; i++)
 145                 dprint(DBG_EXTENT, " %u:%u", be32_to_cpu(extent[i].start_block),
 146                                  be32_to_cpu(extent[i].block_count));
 147         dprint(DBG_EXTENT, "\n");
 148 }
 149
 150 static int hfsplus_add_extent(hfsplus_extent *extent, u32 offset,
 151                               u32 alloc_block, u32 block_count)
 152 {
 153         u32 count, start;
 154         int i;
 155
 156         hfsplus_dump_extent(extent);
 157         for (i = 0; i < 8; extent++, i++) {
 158                 count = be32_to_cpu(extent->block_count);
 159                 if (offset == count) {
 160                         start = be32_to_cpu(extent->start_block);
 161                         if (alloc_block != start + count) {
 162                                 if (++i >= 8)
 163                                         return -ENOSPC;
 164                                 extent++;
 165                                 extent->start_block = cpu_to_be32(alloc_block);
 166                         } else
 167                                 block_count += count;
 168                         extent->block_count = cpu_to_be32(block_count);
 169                         return 0;
 170                 } else if (offset < count)
 171                         break;
 172                 offset -= count;
 173         }
 174         /* panic? */
 175         return -EIO;
 176 }
 177
 178 void hfsplus_free_blocks(struct super_block *sb, u32 start, u32 count)
 179 {
 180         struct inode *anode;
 181         struct buffer_head *bh;
 182         int size, blk, off;
 183         unsigned long *data, word, m;
 184
 185         anode = HFSPLUS_SB(sb).alloc_file;
 186         size = sb->s_blocksize / sizeof(unsigned long);
 187         blk = (start >> sb->s_blocksize_bits) / 8;
 188         off = (start & (sb->s_blocksize * 8 - 1)) / 8 / sizeof(unsigned long);
 189         m = 1 << (~start & (8 * sizeof(unsigned long) - 1));
 190
 191         HFSPLUS_SB(sb).free_blocks += count;
 192         sb->s_dirt = 1;
 193
 194         while (count) {
 195                 bh = hfsplus_getblk(anode, blk);
 196                 data = (unsigned long *)bh->b_data;
 197                 do {
 198                         word = ~be32_to_cpu(data[off]);
 199                         for (;;) {
 200                                 if (word & m)
 201                                         printk("freeing free block %u\n", start);
 202                                 word |= m;
 203                                 start++;
 204                                 if (!--count) {
 205                                         data[off] = cpu_to_be32(~word);
 206                                         goto done;
 207                                 }
 208                                 if (!(m >>= 1))
 209                                         break;
 210                         }
 211                         data[off] = cpu_to_be32(~word);
 212                         m = 1UL << (8 * sizeof(unsigned long) - 1);
 213                 } while (++off < size);
 214         done:
 215                 mark_buffer_dirty_inode(bh, anode);
 216                 brelse(bh);
 217                 if (++blk >= anode->i_blocks)
 218                         break;
 219                 off = 0;
 220         }
 221         if (count)
 222                 printk("%u block left to free\n", count);
 223 }
 224
 225 int hfsplus_free_extents(struct super_block *sb, hfsplus_extent *extent,
 226                          u32 offset, u32 block_nr)
 227 {
 228         u32 count, start;
 229         int i;
 230
 231         hfsplus_dump_extent(extent);
 232         for (i = 0; i < 8; extent++, i++) {
 233                 count = be32_to_cpu(extent->block_count);
 234                 if (offset == count)
 235                         goto found;
 236                 else if (offset < count)
 237                         break;
 238                 offset -= count;
 239         }
 240         /* panic? */
 241         return -EIO;
 242 found:
 243         for (;;) {
 244                 start = be32_to_cpu(extent->start_block);
 245                 if (count <= block_nr) {
 246                         hfsplus_free_blocks(sb, start, count);
 247                         extent->block_count = 0;
 248                         extent->start_block = 0;
 249                         block_nr -= count;
 250                 } else {
 251                         count -= block_nr;
 252                         hfsplus_free_blocks(sb, start + count, block_nr);
 253                         extent->block_count = cpu_to_be32(count);
 254                         block_nr = 0;
 255                 }
 256                 if (!block_nr || !i)
 257                         return 0;
 258                 i--;
 259                 extent--;
 260                 count = be32_to_cpu(extent->block_count);
 261         }
 262 }
 263
 264 int hfsplus_free_fork(struct super_block *sb, u32 cnid, hfsplus_fork_raw *fork, int type)
 265 {
 266         struct hfsplus_find_data fd;
 267         hfsplus_extent_rec ext_entry;
 268         u32 total_blocks, blocks, start;
 269         int res, i;
 270
 271         total_blocks = be32_to_cpu(fork->total_blocks);
 272         if (!total_blocks)
 273                 return 0;
 274
 275         blocks = 0;
 276         for (i = 0; i < 8; i++)
 277                 blocks += be32_to_cpu(fork->extents[i].block_count);
 278
 279         res = hfsplus_free_extents(sb, fork->extents, blocks, blocks);
 280         if (res)
 281                 return res;
 282         if (total_blocks == blocks)
 283                 return 0;
 284
 285         hfsplus_find_init(HFSPLUS_SB(sb).ext_tree, &fd);
 286         do {
 287                 hfsplus_fill_ext_key(fd.search_key, cnid,
 288                                      total_blocks, type);
 289                 res = hfsplus_find_extentry(&fd, ext_entry);
 290                 if (res)
 291                         break;
 292                 start = be32_to_cpu(fd.key->ext.start_block);
 293                 hfsplus_free_extents(sb, ext_entry,
 294                                      total_blocks - start,
 295                                      total_blocks);
 296                 hfsplus_bnode_remove_rec(&fd);
 297                 total_blocks = start;
 298         } while (total_blocks > blocks);
 299         hfsplus_find_exit(&fd);
 300
 301         return res;
 302 }
 303
 304 int hfsplus_extend_file(struct inode *inode)
 305 {
 306         struct super_block *sb = inode->i_sb;
 307         struct inode *anode = HFSPLUS_SB(sb).alloc_file;
 308         struct hfsplus_find_data fd;
 309         hfsplus_extent_rec ext_entry;
 310         struct buffer_head *bh;
 311         u32 blk, blk1, ablock, block_count;
 312         unsigned long *data, word, m;
 313         int res, size, off, i;
 314
 315         if (anode->i_size * 8 < HFSPLUS_SB(sb).total_blocks - HFSPLUS_SB(sb).free_blocks + 8) {
 316                 // extend alloc file
 317                 BUG();
 318         }
 319         blk = blk1 = (HFSPLUS_SB(sb).next_alloc >> sb->s_blocksize_bits) / 8;
 320         off = (HFSPLUS_SB(sb).next_alloc & (sb->s_blocksize * 8 - 1)) / sizeof(unsigned long) / 8;
 321
 322         for (;;) {
 323                 // ignore first off for now...
 324                 off = 0;
 325                 bh = hfsplus_getblk(anode, blk);
 326                 if (blk == anode->i_blocks - 1)
 327                         size = (HFSPLUS_SB(sb).total_blocks &
 328                                 (sb->s_blocksize * 8 - 1)) /
 329                                 8 / sizeof(unsigned long);
 330                 else
 331                         size = sb->s_blocksize / sizeof(unsigned long);
 332                 data = (unsigned long *)bh->b_data;
 333                 do {
 334                         word = be32_to_cpu(data[off]);
 335                         if (!~word)
 336                                 continue;
 337                         m = 1UL << (sizeof(unsigned long) * 8 - 1);
 338                         for (i = 0; m; i++, m >>= 1) {
 339                                 if (word & m)
 340                                         continue;
 341                                 ablock = (blk << sb->s_blocksize_bits) * 8 +
 342                                         off * sizeof(unsigned long) * 8 + i;
 343                                 block_count = 1;
 344                                 word |= m;
 345 #if 0
 346                                 while ((m >>= 1) && !(word & m)) {
 347                                         block_count++;
 348                                         word |= m;
 349                                 }
 350 #endif
 351                                 data[off] = cpu_to_be32(word);
 352                                 mark_buffer_dirty_inode(bh, anode);
 353                                 brelse(bh);
 354                                 goto found;
 355                         }
 356                 } while (++off < size);
 357                 brelse(bh);
 358                 if (++blk >= anode->i_blocks)
 359                         blk = 0;
 360                 if (blk == blk1)
 361                         return -ENOSPC;
 362         }
 363
 364 found:
 365         dprint(DBG_EXTENT, "extend %lu: %u,%u\n", inode->i_ino, ablock, block_count);
 366         if (HFSPLUS_I(inode).alloc_blocks <= HFSPLUS_I(inode).extent_blocks) {
 367                 if (!HFSPLUS_I(inode).extent_blocks) {
 368                         dprint(DBG_EXTENT, "first extents\n");
 369                         /* no extents yet */
 370                         HFSPLUS_I(inode).extents[0].start_block = cpu_to_be32(ablock);
 371                         HFSPLUS_I(inode).extents[0].block_count = cpu_to_be32(block_count);
 372                         res = 0;
 373                 } else
 374                         /* try to append to extents in inode */
 375                         res = hfsplus_add_extent(HFSPLUS_I(inode).extents,
 376                                                  HFSPLUS_I(inode).alloc_blocks,
 377                                                  ablock, block_count);
 378                 if (!res) {
 379                         hfsplus_dump_extent(HFSPLUS_I(inode).extents);
 380                         HFSPLUS_I(inode).extent_blocks += block_count;
 381                 } else if (res == -ENOSPC) {
 382                         /* create new extent, so find place to insert it */
 383                         hfsplus_find_init(HFSPLUS_SB(sb).ext_tree, &fd);
 384                         hfsplus_fill_ext_key(fd.search_key, inode->i_ino,
 385                                              HFSPLUS_I(inode).alloc_blocks,
 386                                              HFSPLUS_IS_RSRC(inode) ?
 387                                              HFSPLUS_TYPE_RSRC : HFSPLUS_TYPE_DATA);
 388                         res = hfsplus_find_extentry(&fd, ext_entry);
 389                         if (res && res != -ENOENT) {
 390                                 hfsplus_find_exit(&fd);
 391                                 goto out;
 392                         }
 393                         goto insert_extent;
 394                 }
 395         } else {
 396                 hfsplus_find_init(HFSPLUS_SB(sb).ext_tree, &fd);
 397                 hfsplus_fill_ext_key(fd.search_key, inode->i_ino,
 398                                      HFSPLUS_I(inode).alloc_blocks,
 399                                      HFSPLUS_IS_RSRC(inode) ?
 400                                      HFSPLUS_TYPE_RSRC : HFSPLUS_TYPE_DATA);
 401                 res = hfsplus_find_extentry(&fd, ext_entry);
 402                 if (res) {
 403                         hfsplus_find_exit(&fd);
 404                         goto out;
 405                 }
 406
 407                 res = hfsplus_add_extent(ext_entry, HFSPLUS_I(inode).alloc_blocks -
 408                                          be32_to_cpu(fd.key->ext.start_block),
 409                                          ablock, block_count);
 410                 if (!res) {
 411                         hfsplus_dump_extent(ext_entry);
 412                         hfsplus_bnode_writebytes(fd.bnode, &ext_entry,
 413                                                  fd.entryoffset,
 414                                                  sizeof(ext_entry));
 415                 } else if (res == -ENOSPC)
 416                         goto insert_extent;
 417                 hfsplus_find_exit(&fd);
 418         }
 419 out:
 420         if (!res) {
 421                 HFSPLUS_I(inode).alloc_blocks += block_count;
 422                 mark_inode_dirty(inode);
 423                 HFSPLUS_SB(sb).free_blocks -= block_count;
 424                 sb->s_dirt = 1;
 425         }
 426         return res;
 427
 428 insert_extent:
 429         dprint(DBG_EXTENT, "insert new extent\n");
 430         memset(ext_entry, 0, sizeof(ext_entry));
 431         ext_entry[0].start_block = cpu_to_be32(ablock);
 432         ext_entry[0].block_count = cpu_to_be32(block_count);
 433
 434         hfsplus_bnode_insert_rec(&fd, ext_entry, sizeof(ext_entry));
 435         hfsplus_find_exit(&fd);
 436         res = 0;
 437         goto out;
 438 }
 439
 440 void hfsplus_truncate(struct inode *inode)
 441 {
 442         struct super_block *sb = inode->i_sb;
 443         struct hfsplus_find_data fd;
 444         hfsplus_extent_rec ext_entry;
 445         u32 blk_cnt, start;
 446         int res;
 447
 448         dprint(DBG_INODE, "truncate: %lu, %Lu -> %Lu\n", inode->i_ino,
 449                (long long)HFSPLUS_I(inode).mmu_private, inode->i_size);
 450         if (inode->i_size == HFSPLUS_I(inode).mmu_private)
 451                 return;
 452         if (inode->i_size > HFSPLUS_I(inode).mmu_private) {
 453                 struct address_space *mapping = inode->i_mapping;
 454                 struct page *page;
 455                 u32 size = inode->i_size - 1;
 456                 int res;
 457
 458                 page = grab_cache_page(mapping, size >> PAGE_CACHE_SHIFT);
 459                 if (!page)
 460                         return;
 461                 size &= PAGE_CACHE_SIZE - 1;
 462                 size++;
 463                 res = mapping->a_ops->prepare_write(NULL, page, size, size);
 464                 if (!res)
 465                         res = mapping->a_ops->commit_write(NULL, page, size, size);
 466                 if (res)
 467                         inode->i_size = HFSPLUS_I(inode).mmu_private;
 468                 unlock_page(page);
 469                 page_cache_release(page);
 470                 mark_inode_dirty(inode);
 471                 return;
 472         }
 473         blk_cnt = (inode->i_size + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
 474
 475         while (1) {
 476                 if (HFSPLUS_I(inode).alloc_blocks <= HFSPLUS_I(inode).extent_blocks) {
 477                         hfsplus_free_extents(sb, HFSPLUS_I(inode).extents,
 478                                              HFSPLUS_I(inode).alloc_blocks,
 479                                              HFSPLUS_I(inode).alloc_blocks - blk_cnt);
 480                         hfsplus_dump_extent(HFSPLUS_I(inode).extents);
 481                         HFSPLUS_I(inode).extent_blocks = blk_cnt;
 482                         break;
 483                 }
 484                 hfsplus_find_init(HFSPLUS_SB(sb).ext_tree, &fd);
 485                 hfsplus_fill_ext_key(fd.search_key, inode->i_ino,
 486                                      HFSPLUS_I(inode).alloc_blocks,
 487                                      HFSPLUS_IS_RSRC(inode) ?
 488                                      HFSPLUS_TYPE_RSRC : HFSPLUS_TYPE_DATA);
 489                 res = hfsplus_find_extentry(&fd, ext_entry);
 490                 if (res) {
 491                         hfsplus_find_exit(&fd);
 492                         break;
 493                 }
 494                 start = be32_to_cpu(fd.key->ext.start_block);
 495                 hfsplus_free_extents(sb, ext_entry,
 496                                      HFSPLUS_I(inode).alloc_blocks - start,
 497                                      HFSPLUS_I(inode).alloc_blocks - blk_cnt);
 498                 hfsplus_dump_extent(ext_entry);
 499                 if (blk_cnt > start) {
 500                         hfsplus_bnode_writebytes(fd.bnode, &ext_entry,
 501                                                  fd.entryoffset,
 502                                                  sizeof(ext_entry));
 503                         hfsplus_find_exit(&fd);
 504                         break;
 505                 }
 506                 HFSPLUS_I(inode).alloc_blocks = start;
 507                 hfsplus_bnode_remove_rec(&fd);
 508                 hfsplus_find_exit(&fd);
 509         }
 510         HFSPLUS_I(inode).mmu_private = inode->i_size;
 511         HFSPLUS_I(inode).alloc_blocks = HFSPLUS_I(inode).total_blocks = blk_cnt;
 512 }