Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 | /*
* linux/fs/hfs/extent.c
*
* Copyright (C) 1995-1997 Paul H. Hargrove
* This file may be distributed under the terms of the GNU Public License.
*
* This file contains the functions related to the extents B-tree.
*
* "XXX" in a comment is a note to myself to consider changing something.
*
* In function preconditions the term "valid" applied to a pointer to
* a structure means that the pointer is non-NULL and the structure it
* points to has all fields initialized to consistent values.
*/
#include "hfs.h"
/*================ File-local data type ================*/
/* An extent record on disk*/
struct hfs_raw_extent {
hfs_word_t block1;
hfs_word_t length1;
hfs_word_t block2;
hfs_word_t length2;
hfs_word_t block3;
hfs_word_t length3;
};
/*================ File-local functions ================*/
/*
* build_key
*/
static inline void build_key(struct hfs_ext_key *key,
const struct hfs_fork *fork, hfs_u16 block)
{
key->KeyLen = 7;
key->FkType = fork->fork;
hfs_put_nl(fork->entry->cnid, key->FNum);
hfs_put_hs(block, key->FABN);
}
/*
* lock_bitmap()
*
* Get an exclusive lock on the B-tree bitmap.
*/
static inline void lock_bitmap(struct hfs_mdb *mdb) {
while (mdb->bitmap_lock) {
hfs_sleep_on(&mdb->bitmap_wait);
}
mdb->bitmap_lock = 1;
}
/*
* unlock_bitmap()
*
* Relinquish an exclusive lock on the B-tree bitmap.
*/
static inline void unlock_bitmap(struct hfs_mdb *mdb) {
mdb->bitmap_lock = 0;
hfs_wake_up(&mdb->bitmap_wait);
}
/*
* dump_ext()
*
* prints the content of a extent for debugging purposes.
*/
#if defined(DEBUG_EXTENTS) || defined(DEBUG_ALL)
static void dump_ext(const char *msg, const struct hfs_extent *e) {
if (e) {
hfs_warn("%s (%d-%d) (%d-%d) (%d-%d)\n", msg,
e->start,
e->start + e->length[0] - 1,
e->start + e->length[0],
e->start + e->length[0] + e->length[1] - 1,
e->start + e->length[0] + e->length[1],
e->end);
} else {
hfs_warn("%s NULL\n", msg);
}
}
#else
#define dump_ext(A,B) {}
#endif
/*
* read_extent()
*
* Initializes a (struct hfs_extent) from a (struct hfs_raw_extent) and
* the number of the starting block for the extent.
*
* Note that the callers must check that to,from != NULL
*/
static void read_extent(struct hfs_extent *to,
const struct hfs_raw_extent *from,
hfs_u16 start)
{
to->start = start;
to->block[0] = hfs_get_hs(from->block1);
to->length[0] = hfs_get_hs(from->length1);
to->block[1] = hfs_get_hs(from->block2);
to->length[1] = hfs_get_hs(from->length2);
to->block[2] = hfs_get_hs(from->block3);
to->length[2] = hfs_get_hs(from->length3);
to->end = start + to->length[0] + to->length[1] + to->length[2] - 1;
to->next = to->prev = NULL;
to->count = 0;
}
/*
* write_extent()
*
* Initializes a (struct hfs_raw_extent) from a (struct hfs_extent).
*
* Note that the callers must check that to,from != NULL
*/
static void write_extent(struct hfs_raw_extent *to,
const struct hfs_extent *from)
{
hfs_put_hs(from->block[0], to->block1);
hfs_put_hs(from->length[0], to->length1);
hfs_put_hs(from->block[1], to->block2);
hfs_put_hs(from->length[1], to->length2);
hfs_put_hs(from->block[2], to->block3);
hfs_put_hs(from->length[2], to->length3);
}
/*
* decode_extent()
*
* Given an extent record and allocation block offset into the file,
* return the number of the corresponding allocation block on disk,
* or -1 if the desired block is not mapped by the given extent.
*
* Note that callers must check that extent != NULL
*/
static int decode_extent(const struct hfs_extent * extent, int block)
{
if (!extent || (block < extent->start) || (block > extent->end) ||
(extent->end == (hfs_u16)(extent->start - 1))) {
return -1;
}
block -= extent->start;
if (block < extent->length[0]) {
return block + extent->block[0];
}
block -= extent->length[0];
if (block < extent->length[1]) {
return block + extent->block[1];
}
return block + extent->block[2] - extent->length[1];
}
/*
* relse_ext()
*
* Reduce the reference count of an in-core extent record by one,
* removing it from memory if the count falls to zero.
*/
static void relse_ext(struct hfs_extent *ext)
{
if (--ext->count || !ext->start) {
return;
}
ext->prev->next = ext->next;
if (ext->next) {
ext->next->prev = ext->prev;
}
HFS_DELETE(ext);
}
/*
* set_cache()
*
* Changes the 'cache' field of the fork.
*/
static inline void set_cache(struct hfs_fork *fork, struct hfs_extent *ext)
{
struct hfs_extent *tmp = fork->cache;
++ext->count;
fork->cache = ext;
relse_ext(tmp);
}
/*
* find_ext()
*
* Given a pointer to a (struct hfs_file) and an allocation block
* number in the file, find the extent record containing that block.
* Returns a pointer to the extent record on success or NULL on failure.
* The 'cache' field of 'fil' also points to the extent so it has a
* reference count of at least 2.
*
* Callers must check that fil != NULL
*/
static struct hfs_extent * find_ext(struct hfs_fork *fork, int alloc_block)
{
struct hfs_cat_entry *entry = fork->entry;
struct hfs_btree *tr= entry->mdb->ext_tree;
struct hfs_ext_key target, *key;
struct hfs_brec brec;
struct hfs_extent *ext, *ptr;
int tmp;
if (alloc_block < 0) {
ext = &fork->first;
goto found;
}
ext = fork->cache;
if (!ext || (alloc_block < ext->start)) {
ext = &fork->first;
}
while (ext->next && (alloc_block > ext->end)) {
ext = ext->next;
}
if ((alloc_block <= ext->end) && (alloc_block >= ext->start)) {
goto found;
}
/* time to read more extents */
if (!HFS_NEW(ext)) {
goto bail3;
}
build_key(&target, fork, alloc_block);
tmp = hfs_bfind(&brec, tr, HFS_BKEY(&target), HFS_BFIND_READ_LE);
if (tmp < 0) {
goto bail2;
}
key = (struct hfs_ext_key *)brec.key;
if ((hfs_get_nl(key->FNum) != hfs_get_nl(target.FNum)) ||
(key->FkType != fork->fork)) {
goto bail1;
}
read_extent(ext, brec.data, hfs_get_hs(key->FABN));
hfs_brec_relse(&brec, NULL);
if ((alloc_block > ext->end) && (alloc_block < ext->start)) {
/* something strange happened */
goto bail2;
}
ptr = fork->cache;
if (!ptr || (alloc_block < ptr->start)) {
ptr = &fork->first;
}
while (ptr->next && (alloc_block > ptr->end)) {
ptr = ptr->next;
}
if (ext->start == ptr->start) {
/* somebody beat us to it. */
HFS_DELETE(ext);
ext = ptr;
} else if (ext->start < ptr->start) {
/* insert just before ptr */
ptr->prev->next = ext;
ext->prev = ptr->prev;
ext->next = ptr;
ptr->prev = ext;
} else {
/* insert at end */
ptr->next = ext;
ext->prev = ptr;
}
found:
++ext->count; /* for return value */
set_cache(fork, ext);
return ext;
bail1:
hfs_brec_relse(&brec, NULL);
bail2:
HFS_DELETE(ext);
bail3:
return NULL;
}
/*
* delete_extent()
*
* Description:
* Deletes an extent record from a fork, reducing its physical length.
* Input Variable(s):
* struct hfs_fork *fork: the fork
* struct hfs_extent *ext: the current last extent for 'fork'
* Output Variable(s):
* NONE
* Returns:
* void
* Preconditions:
* 'fork' points to a valid (struct hfs_fork)
* 'ext' point to a valid (struct hfs_extent) which is the last in 'fork'
* and which is not also the first extent in 'fork'.
* Postconditions:
* The extent record has been removed if possible, and a warning has been
* printed otherwise.
*/
static void delete_extent(struct hfs_fork *fork, struct hfs_extent *ext)
{
struct hfs_mdb *mdb = fork->entry->mdb;
struct hfs_ext_key key;
int error;
if (fork->cache == ext) {
set_cache(fork, ext->prev);
}
ext->prev->next = NULL;
if (ext->count != 1) {
hfs_warn("hfs_truncate: extent has count %d.\n", ext->count);
}
lock_bitmap(mdb);
error = hfs_clear_vbm_bits(mdb, ext->block[2], ext->length[2]);
if (error) {
hfs_warn("hfs_truncate: error %d freeing blocks.\n", error);
}
error = hfs_clear_vbm_bits(mdb, ext->block[1], ext->length[1]);
if (error) {
hfs_warn("hfs_truncate: error %d freeing blocks.\n", error);
}
error = hfs_clear_vbm_bits(mdb, ext->block[0], ext->length[0]);
if (error) {
hfs_warn("hfs_truncate: error %d freeing blocks.\n", error);
}
unlock_bitmap(mdb);
build_key(&key, fork, ext->start);
error = hfs_bdelete(mdb->ext_tree, HFS_BKEY(&key));
if (error) {
hfs_warn("hfs_truncate: error %d deleting an extent.\n", error);
}
HFS_DELETE(ext);
}
/*
* new_extent()
*
* Description:
* Adds a new extent record to a fork, extending its physical length.
* Input Variable(s):
* struct hfs_fork *fork: the fork to extend
* struct hfs_extent *ext: the current last extent for 'fork'
* hfs_u16 ablock: the number of allocation blocks in 'fork'.
* hfs_u16 start: first allocation block to add to 'fork'.
* hfs_u16 len: the number of allocation blocks to add to 'fork'.
* hfs_u32 ablksz: number of sectors in an allocation block.
* Output Variable(s):
* NONE
* Returns:
* (struct hfs_extent *) the new extent or NULL
* Preconditions:
* 'fork' points to a valid (struct hfs_fork)
* 'ext' point to a valid (struct hfs_extent) which is the last in 'fork'
* 'ablock', 'start', 'len' and 'ablksz' are what they claim to be.
* Postconditions:
* If NULL is returned then no changes have been made to 'fork'.
* If the return value is non-NULL that it is the extent that has been
* added to 'fork' both in memory and on disk. The 'psize' field of
* 'fork' has been updated to reflect the new physical size.
*/
static struct hfs_extent *new_extent(struct hfs_fork *fork,
struct hfs_extent *ext,
hfs_u16 ablock, hfs_u16 start,
hfs_u16 len, hfs_u16 ablksz)
{
struct hfs_raw_extent raw;
struct hfs_ext_key key;
int error;
if (fork->entry->cnid == htonl(HFS_EXT_CNID)) {
/* Limit extents tree to the record in the MDB */
return NULL;
}
if (!HFS_NEW(ext->next)) {
return NULL;
}
ext->next->prev = ext;
ext->next->next = NULL;
ext = ext->next;
relse_ext(ext->prev);
ext->start = ablock;
ext->block[0] = start;
ext->length[0] = len;
ext->block[1] = 0;
ext->length[1] = 0;
ext->block[2] = 0;
ext->length[2] = 0;
ext->end = ablock + len - 1;
ext->count = 1;
write_extent(&raw, ext);
build_key(&key, fork, ablock);
error = hfs_binsert(fork->entry->mdb->ext_tree,
HFS_BKEY(&key), &raw, sizeof(raw));
if (error) {
ext->prev->next = NULL;
HFS_DELETE(ext);
return NULL;
}
set_cache(fork, ext);
return ext;
}
/*
* update_ext()
*
* Given a (struct hfs_fork) write an extent record back to disk.
*/
static void update_ext(struct hfs_fork *fork, struct hfs_extent *ext)
{
struct hfs_ext_key target;
struct hfs_brec brec;
if (ext->start) {
build_key(&target, fork, ext->start);
if (!hfs_bfind(&brec, fork->entry->mdb->ext_tree,
HFS_BKEY(&target), HFS_BFIND_WRITE)) {
write_extent(brec.data, ext);
hfs_brec_relse(&brec, NULL);
}
}
}
/*
* zero_blocks()
*
* Zeros-out 'num' allocation blocks beginning with 'start'.
*/
static int zero_blocks(struct hfs_mdb *mdb, int start, int num) {
hfs_buffer buf;
int end;
int j;
start = mdb->fs_start + start * mdb->alloc_blksz;
end = start + num * mdb->alloc_blksz;
for (j=start; j<end; ++j) {
if (hfs_buffer_ok(buf = hfs_buffer_get(mdb->sys_mdb, j, 0))) {
memset(hfs_buffer_data(buf), 0, HFS_SECTOR_SIZE);
hfs_buffer_dirty(buf);
hfs_buffer_put(buf);
}
}
return 0;
}
/*
* shrink_fork()
*
* Try to remove enough allocation blocks from 'fork'
* so that it is 'ablocks' allocation blocks long.
*/
static void shrink_fork(struct hfs_fork *fork, int ablocks)
{
struct hfs_mdb *mdb = fork->entry->mdb;
struct hfs_extent *ext;
int i, error, next, count;
hfs_u32 ablksz = mdb->alloc_blksz;
next = (fork->psize / ablksz) - 1;
ext = find_ext(fork, next);
while (ext && ext->start && (ext->start >= ablocks)) {
next = ext->start - 1;
delete_extent(fork, ext);
ext = find_ext(fork, next);
}
if (!ext) {
fork->psize = (next + 1) * ablksz;
return;
}
if ((count = next + 1 - ablocks) > 0) {
for (i=2; (i>=0) && !ext->length[i]; --i) {};
lock_bitmap(mdb);
while (count && (ext->length[i] <= count)) {
ext->end -= ext->length[i];
count -= ext->length[i];
error = hfs_clear_vbm_bits(mdb, ext->block[i],
ext->length[i]);
if (error) {
hfs_warn("hfs_truncate: error %d freeing "
"blocks.\n", error);
}
ext->block[i] = ext->length[i] = 0;
--i;
}
if (count) {
ext->end -= count;
ext->length[i] -= count;
error = hfs_clear_vbm_bits(mdb, ext->block[i] +
ext->length[i], count);
if (error) {
hfs_warn("hfs_truncate: error %d freeing "
"blocks.\n", error);
}
}
unlock_bitmap(mdb);
update_ext(fork, ext);
}
fork->psize = ablocks * ablksz;
}
/*
* grow_fork()
*
* Try to add enough allocation blocks to 'fork'
* so that it is 'ablock' allocation blocks long.
*/
static int grow_fork(struct hfs_fork *fork, int ablocks)
{
struct hfs_cat_entry *entry = fork->entry;
struct hfs_mdb *mdb = entry->mdb;
struct hfs_extent *ext;
int i, start, err;
hfs_u16 need, len=0;
hfs_u32 ablksz = mdb->alloc_blksz;
hfs_u32 blocks, clumpablks;
blocks = fork->psize;
need = ablocks - blocks/ablksz;
if (need < 1) { /* no need to grow the fork */
return 0;
}
/* round up to clumpsize */
if (entry->u.file.clumpablks) {
clumpablks = entry->u.file.clumpablks;
} else {
clumpablks = mdb->clumpablks;
}
need = ((need + clumpablks - 1) / clumpablks) * clumpablks;
/* find last extent record and try to extend it */
if (!(ext = find_ext(fork, blocks/ablksz - 1))) {
/* somehow we couldn't find the end of the file! */
return -1;
}
/* determine which is the last used extent in the record */
/* then try to allocate the blocks immediately following it */
for (i=2; (i>=0) && !ext->length[i]; --i) {};
if (i>=0) {
/* try to extend the last extent */
start = ext->block[i] + ext->length[i];
err = 0;
lock_bitmap(mdb);
len = hfs_vbm_count_free(mdb, start);
if (!len) {
unlock_bitmap(mdb);
goto more_extents;
}
if (need < len) {
len = need;
}
err = hfs_set_vbm_bits(mdb, start, len);
unlock_bitmap(mdb);
if (err) {
relse_ext(ext);
return -1;
}
zero_blocks(mdb, start, len);
ext->length[i] += len;
ext->end += len;
blocks = (fork->psize += len * ablksz);
need -= len;
update_ext(fork, ext);
}
more_extents:
/* add some more extents */
while (need) {
len = need;
err = 0;
lock_bitmap(mdb);
start = hfs_vbm_search_free(mdb, &len);
if (need < len) {
len = need;
}
err = hfs_set_vbm_bits(mdb, start, len);
unlock_bitmap(mdb);
if (!len || err) {
relse_ext(ext);
return -1;
}
zero_blocks(mdb, start, len);
/* determine which is the first free extent in the record */
for (i=0; (i<3) && ext->length[i]; ++i) {};
if (i < 3) {
ext->block[i] = start;
ext->length[i] = len;
ext->end += len;
update_ext(fork, ext);
} else {
if (!(ext = new_extent(fork, ext, blocks/ablksz,
start, len, ablksz))) {
lock_bitmap(mdb);
hfs_clear_vbm_bits(mdb, start, len);
unlock_bitmap(mdb);
return -1;
}
}
blocks = (fork->psize += len * ablksz);
need -= len;
}
set_cache(fork, ext);
relse_ext(ext);
return 0;
}
/*================ Global functions ================*/
/*
* hfs_ext_compare()
*
* Description:
* This is the comparison function used for the extents B-tree. In
* comparing extent B-tree entries, the file id is the most
* significant field (compared as unsigned ints); the fork type is
* the second most significant field (compared as unsigned chars);
* and the allocation block number field is the least significant
* (compared as unsigned ints).
* Input Variable(s):
* struct hfs_ext_key *key1: pointer to the first key to compare
* struct hfs_ext_key *key2: pointer to the second key to compare
* Output Variable(s):
* NONE
* Returns:
* int: negative if key1<key2, positive if key1>key2, and 0 if key1==key2
* Preconditions:
* key1 and key2 point to "valid" (struct hfs_ext_key)s.
* Postconditions:
* This function has no side-effects */
int hfs_ext_compare(const struct hfs_ext_key *key1,
const struct hfs_ext_key *key2)
{
unsigned int tmp;
int retval;
tmp = hfs_get_hl(key1->FNum) - hfs_get_hl(key2->FNum);
if (tmp != 0) {
retval = (int)tmp;
} else {
tmp = (unsigned char)key1->FkType - (unsigned char)key2->FkType;
if (tmp != 0) {
retval = (int)tmp;
} else {
retval = (int)(hfs_get_hs(key1->FABN)
- hfs_get_hs(key2->FABN));
}
}
return retval;
}
/*
* hfs_extent_adj()
*
* Given an hfs_fork shrink or grow the fork to hold the
* forks logical size.
*/
void hfs_extent_adj(struct hfs_fork *fork)
{
if (fork) {
hfs_u32 blks, ablocks, ablksz;
if (fork->lsize > HFS_FORK_MAX) {
fork->lsize = HFS_FORK_MAX;
}
blks = (fork->lsize+HFS_SECTOR_SIZE-1) >> HFS_SECTOR_SIZE_BITS;
ablksz = fork->entry->mdb->alloc_blksz;
ablocks = (blks + ablksz - 1) / ablksz;
if (blks > fork->psize) {
grow_fork(fork, ablocks);
if (blks > fork->psize) {
fork->lsize =
fork->psize >> HFS_SECTOR_SIZE_BITS;
}
} else if (blks < fork->psize) {
shrink_fork(fork, ablocks);
}
}
}
/*
* hfs_extent_map()
*
* Given an hfs_fork and a block number within the fork, return the
* number of the corresponding physical block on disk, or zero on
* error.
*/
int hfs_extent_map(struct hfs_fork *fork, int block, int create)
{
int ablksz, ablock, offset, tmp;
struct hfs_extent *ext;
if (!fork || !fork->entry || !fork->entry->mdb) {
return 0;
}
#if defined(DEBUG_EXTENTS) || defined(DEBUG_ALL)
hfs_warn("hfs_extent_map: ablock %d of file %d, fork %d\n",
block, fork->entry->cnid, fork->fork);
#endif
if (block < 0) {
hfs_warn("hfs_extent_map: block < 0\n");
return 0;
}
if (block > (HFS_FORK_MAX >> HFS_SECTOR_SIZE_BITS)) {
hfs_warn("hfs_extent_map: block(0x%08x) > big; cnid=%d "
"fork=%d\n", block, fork->entry->cnid, fork->fork);
return 0;
}
ablksz = fork->entry->mdb->alloc_blksz;
offset = fork->entry->mdb->fs_start + (block % ablksz);
ablock = block / ablksz;
if (block >= fork->psize) {
if (!create || (grow_fork(fork, ablock + 1) < 0))
return 0;
}
#if defined(DEBUG_EXTENTS) || defined(DEBUG_ALL)
hfs_warn("(lblock %d offset %d)\n", ablock, offset);
#endif
if ((ext = find_ext(fork, ablock))) {
dump_ext("trying new: ", ext);
tmp = decode_extent(ext, ablock);
relse_ext(ext);
if (tmp >= 0) {
return tmp*ablksz + offset;
}
}
return 0;
}
/*
* hfs_extent_out()
*
* Copy the first extent record from a (struct hfs_fork) to a (struct
* raw_extent), record (normally the one in the catalog entry).
*/
void hfs_extent_out(const struct hfs_fork *fork, hfs_byte_t dummy[12])
{
struct hfs_raw_extent *ext = (struct hfs_raw_extent *)dummy;
if (fork && ext) {
write_extent(ext, &fork->first);
dump_ext("extent out: ", &fork->first);
}
}
/*
* hfs_extent_in()
*
* Copy an raw_extent to the 'first' and 'cache' fields of an hfs_fork.
*/
void hfs_extent_in(struct hfs_fork *fork, const hfs_byte_t dummy[12])
{
const struct hfs_raw_extent *ext =
(const struct hfs_raw_extent *)dummy;
if (fork && ext) {
read_extent(&fork->first, ext, 0);
fork->cache = &fork->first;
fork->first.count = 2;
dump_ext("extent in: ", &fork->first);
}
}
/*
* hfs_extent_free()
*
* Removes from memory all extents associated with 'fil'.
*/
void hfs_extent_free(struct hfs_fork *fork)
{
if (fork) {
set_cache(fork, &fork->first);
if (fork->first.next) {
hfs_warn("hfs_extent_free: extents in use!\n");
}
}
}
|