1 /* 2 * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com 3 * Written by Alex Tomas <alex@clusterfs.com> 4 * 5 * Architecture independence: 6 * Copyright (c) 2005, Bull S.A. 7 * Written by Pierre Peiffer <pierre.peiffer@bull.net> 8 * 9 * This program is free software; you can redistribute it and/or modify 10 * it under the terms of the GNU General Public License version 2 as 11 * published by the Free Software Foundation. 12 * 13 * This program is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 * GNU General Public License for more details. 17 * 18 * You should have received a copy of the GNU General Public Licens 19 * along with this program; if not, write to the Free Software 20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111- 21 */ 22 23 /* 24 * Extents support for EXT4 25 * 26 * TODO: 27 * - ext4*_error() should be used in some situations 28 * - analyze all BUG()/BUG_ON(), use -EIO where appropriate 29 * - smart tree reduction 30 */ 31 32 #include <linux/module.h> 33 #include <linux/fs.h> 34 #include <linux/time.h> 35 #include <linux/jbd2.h> 36 #include <linux/highuid.h> 37 #include <linux/pagemap.h> 38 #include <linux/quotaops.h> 39 #include <linux/string.h> 40 #include <linux/slab.h> 41 #include <linux/falloc.h> 42 #include <asm/uaccess.h> 43 #include <linux/fiemap.h> 44 #include "ext4_jbd2.h" 45 #include "ext4_extents.h" 46 47 48 /* 49 * ext_pblock: 50 * combine low and high parts of physical block number into ext4_fsblk_t 51 */ 52 ext4_fsblk_t ext_pblock(struct ext4_extent *ex) 53 { 54 ext4_fsblk_t block; 55 56 block = le32_to_cpu(ex->ee_start_lo); 57 block |= ((ext4_fsblk_t) le16_to_cpu(ex->ee_start_hi) << 31) << 1; 58 return block; 59 } 60 61 /* 62 * idx_pblock: 63 * combine low and high parts of a leaf physical block number into ext4_fsblk_t 64 */ 65 ext4_fsblk_t idx_pblock(struct ext4_extent_idx *ix) 66 { 67 ext4_fsblk_t block; 68 69 block = le32_to_cpu(ix->ei_leaf_lo); 70 block |= ((ext4_fsblk_t) le16_to_cpu(ix->ei_leaf_hi) << 31) << 1; 71 return block; 72 } 73 74 /* 75 * ext4_ext_store_pblock: 76 * stores a large physical block number into an extent struct, 77 * breaking it into parts 78 */ 79 void ext4_ext_store_pblock(struct ext4_extent *ex, ext4_fsblk_t pb) 80 { 81 ex->ee_start_lo = cpu_to_le32((unsigned long) (pb & 0xffffffff)); 82 ex->ee_start_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) & 0xffff); 83 } 84 85 /* 86 * ext4_idx_store_pblock: 87 * stores a large physical block number into an index struct, 88 * breaking it into parts 89 */ 90 static void ext4_idx_store_pblock(struct ext4_extent_idx *ix, ext4_fsblk_t pb) 91 { 92 ix->ei_leaf_lo = cpu_to_le32((unsigned long) (pb & 0xffffffff)); 93 ix->ei_leaf_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) & 0xffff); 94 } 95 96 static int ext4_ext_truncate_extend_restart(handle_t *handle, 97 struct inode *inode, 98 int needed) 99 { 100 int err; 101 102 if (!ext4_handle_valid(handle)) 103 return 0; 104 if (handle->h_buffer_credits > needed) 105 return 0; 106 err = ext4_journal_extend(handle, needed); 107 if (err <= 0) 108 return err; 109 err = ext4_truncate_restart_trans(handle, inode, needed); 110 /* 111 * We have dropped i_data_sem so someone might have cached again 112 * an extent we are going to truncate. 113 */ 114 ext4_ext_invalidate_cache(inode); 115 116 return err; 117 } 118 119 /* 120 * could return: 121 * - EROFS 122 * - ENOMEM 123 */ 124 static int ext4_ext_get_access(handle_t *handle, struct inode *inode, 125 struct ext4_ext_path *path) 126 { 127 if (path->p_bh) { 128 /* path points to block */ 129 return ext4_journal_get_write_access(handle, path->p_bh); 130 } 131 /* path points to leaf/index in inode body */ 132 /* we use in-core data, no need to protect them */ 133 return 0; 134 } 135 136 /* 137 * could return: 138 * - EROFS 139 * - ENOMEM 140 * - EIO 141 */ 142 static int ext4_ext_dirty(handle_t *handle, struct inode *inode, 143 struct ext4_ext_path *path) 144 { 145 int err; 146 if (path->p_bh) { 147 /* path points to block */ 148 err = ext4_handle_dirty_metadata(handle, inode, path->p_bh); 149 } else { 150 /* path points to leaf/index in inode body */ 151 err = ext4_mark_inode_dirty(handle, inode); 152 } 153 return err; 154 } 155 156 static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode, 157 struct ext4_ext_path *path, 158 ext4_lblk_t block) 159 { 160 struct ext4_inode_info *ei = EXT4_I(inode); 161 ext4_fsblk_t bg_start; 162 ext4_fsblk_t last_block; 163 ext4_grpblk_t colour; 164 ext4_group_t block_group; 165 int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb)); 166 int depth; 167 168 if (path) { 169 struct ext4_extent *ex; 170 depth = path->p_depth; 171 172 /* try to predict block placement */ 173 ex = path[depth].p_ext; 174 if (ex) 175 return ext_pblock(ex)+(block-le32_to_cpu(ex->ee_block)); 176 177 /* it looks like index is empty; 178 * try to find starting block from index itself */ 179 if (path[depth].p_bh) 180 return path[depth].p_bh->b_blocknr; 181 } 182 183 /* OK. use inode's group */ 184 block_group = ei->i_block_group; 185 if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) { 186 /* 187 * If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME 188 * block groups per flexgroup, reserve the first block 189 * group for directories and special files. Regular 190 * files will start at the second block group. This 191 * tends to speed up directory access and improves 192 * fsck times. 193 */ 194 block_group &= ~(flex_size-1); 195 if (S_ISREG(inode->i_mode)) 196 block_group++; 197 } 198 bg_start = ext4_group_first_block_no(inode->i_sb, block_group); 199 last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1; 200 201 /* 202 * If we are doing delayed allocation, we don't need take 203 * colour into account. 204 */ 205 if (test_opt(inode->i_sb, DELALLOC)) 206 return bg_start; 207 208 if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block) 209 colour = (current->pid % 16) * 210 (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16); 211 else 212 colour = (current->pid % 16) * ((last_block - bg_start) / 16); 213 return bg_start + colour + block; 214 } 215 216 /* 217 * Allocation for a meta data block 218 */ 219 static ext4_fsblk_t 220 ext4_ext_new_meta_block(handle_t *handle, struct inode *inode, 221 struct ext4_ext_path *path, 222 struct ext4_extent *ex, int *err) 223 { 224 ext4_fsblk_t goal, newblock; 225 226 goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block)); 227 newblock = ext4_new_meta_blocks(handle, inode, goal, NULL, err); 228 return newblock; 229 } 230 231 static inline int ext4_ext_space_block(struct inode *inode, int check) 232 { 233 int size; 234 235 size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header)) 236 / sizeof(struct ext4_extent); 237 if (!check) { 238 #ifdef AGGRESSIVE_TEST 239 if (size > 6) 240 size = 6; 241 #endif 242 } 243 return size; 244 } 245 246 static inline int ext4_ext_space_block_idx(struct inode *inode, int check) 247 { 248 int size; 249 250 size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header)) 251 / sizeof(struct ext4_extent_idx); 252 if (!check) { 253 #ifdef AGGRESSIVE_TEST 254 if (size > 5) 255 size = 5; 256 #endif 257 } 258 return size; 259 } 260 261 static inline int ext4_ext_space_root(struct inode *inode, int check) 262 { 263 int size; 264 265 size = sizeof(EXT4_I(inode)->i_data); 266 size -= sizeof(struct ext4_extent_header); 267 size /= sizeof(struct ext4_extent); 268 if (!check) { 269 #ifdef AGGRESSIVE_TEST 270 if (size > 3) 271 size = 3; 272 #endif 273 } 274 return size; 275 } 276 277 static inline int ext4_ext_space_root_idx(struct inode *inode, int check) 278 { 279 int size; 280 281 size = sizeof(EXT4_I(inode)->i_data); 282 size -= sizeof(struct ext4_extent_header); 283 size /= sizeof(struct ext4_extent_idx); 284 if (!check) { 285 #ifdef AGGRESSIVE_TEST 286 if (size > 4) 287 size = 4; 288 #endif 289 } 290 return size; 291 } 292 293 /* 294 * Calculate the number of metadata blocks needed 295 * to allocate @blocks 296 * Worse case is one block per extent 297 */ 298 int ext4_ext_calc_metadata_amount(struct inode *inode, sector_t lblock) 299 { 300 struct ext4_inode_info *ei = EXT4_I(inode); 301 int idxs, num = 0; 302 303 idxs = ((inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header)) 304 / sizeof(struct ext4_extent_idx)); 305 306 /* 307 * If the new delayed allocation block is contiguous with the 308 * previous da block, it can share index blocks with the 309 * previous block, so we only need to allocate a new index 310 * block every idxs leaf blocks. At ldxs**2 blocks, we need 311 * an additional index block, and at ldxs**3 blocks, yet 312 * another index blocks. 313 */ 314 if (ei->i_da_metadata_calc_len && 315 ei->i_da_metadata_calc_last_lblock+1 == lblock) { 316 if ((ei->i_da_metadata_calc_len % idxs) == 0) 317 num++; 318 if ((ei->i_da_metadata_calc_len % (idxs*idxs)) == 0) 319 num++; 320 if ((ei->i_da_metadata_calc_len % (idxs*idxs*idxs)) == 0) { 321 num++; 322 ei->i_da_metadata_calc_len = 0; 323 } else 324 ei->i_da_metadata_calc_len++; 325 ei->i_da_metadata_calc_last_lblock++; 326 return num; 327 } 328 329 /* 330 * In the worst case we need a new set of index blocks at 331 * every level of the inode's extent tree. 332 */ 333 ei->i_da_metadata_calc_len = 1; 334 ei->i_da_metadata_calc_last_lblock = lblock; 335 return ext_depth(inode) + 1; 336 } 337 338 static int 339 ext4_ext_max_entries(struct inode *inode, int depth) 340 { 341 int max; 342 343 if (depth == ext_depth(inode)) { 344 if (depth == 0) 345 max = ext4_ext_space_root(inode, 1); 346 else 347 max = ext4_ext_space_root_idx(inode, 1); 348 } else { 349 if (depth == 0) 350 max = ext4_ext_space_block(inode, 1); 351 else 352 max = ext4_ext_space_block_idx(inode, 1); 353 } 354 355 return max; 356 } 357 358 static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext) 359 { 360 ext4_fsblk_t block = ext_pblock(ext); 361 int len = ext4_ext_get_actual_len(ext); 362 363 return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, len); 364 } 365 366 static int ext4_valid_extent_idx(struct inode *inode, 367 struct ext4_extent_idx *ext_idx) 368 { 369 ext4_fsblk_t block = idx_pblock(ext_idx); 370 371 return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, 1); 372 } 373 374 static int ext4_valid_extent_entries(struct inode *inode, 375 struct ext4_extent_header *eh, 376 int depth) 377 { 378 struct ext4_extent *ext; 379 struct ext4_extent_idx *ext_idx; 380 unsigned short entries; 381 if (eh->eh_entries == 0) 382 return 1; 383 384 entries = le16_to_cpu(eh->eh_entries); 385 386 if (depth == 0) { 387 /* leaf entries */ 388 ext = EXT_FIRST_EXTENT(eh); 389 while (entries) { 390 if (!ext4_valid_extent(inode, ext)) 391 return 0; 392 ext++; 393 entries--; 394 } 395 } else { 396 ext_idx = EXT_FIRST_INDEX(eh); 397 while (entries) { 398 if (!ext4_valid_extent_idx(inode, ext_idx)) 399 return 0; 400 ext_idx++; 401 entries--; 402 } 403 } 404 return 1; 405 } 406 407 static int __ext4_ext_check(const char *function, struct inode *inode, 408 struct ext4_extent_header *eh, 409 int depth) 410 { 411 const char *error_msg; 412 int max = 0; 413 414 if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) { 415 error_msg = "invalid magic"; 416 goto corrupted; 417 } 418 if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) { 419 error_msg = "unexpected eh_depth"; 420 goto corrupted; 421 } 422 if (unlikely(eh->eh_max == 0)) { 423 error_msg = "invalid eh_max"; 424 goto corrupted; 425 } 426 max = ext4_ext_max_entries(inode, depth); 427 if (unlikely(le16_to_cpu(eh->eh_max) > max)) { 428 error_msg = "too large eh_max"; 429 goto corrupted; 430 } 431 if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) { 432 error_msg = "invalid eh_entries"; 433 goto corrupted; 434 } 435 if (!ext4_valid_extent_entries(inode, eh, depth)) { 436 error_msg = "invalid extent entries"; 437 goto corrupted; 438 } 439 return 0; 440 441 corrupted: 442 __ext4_error(inode->i_sb, function, 443 "bad header/extent in inode #%lu: %s - magic %x, " 444 "entries %u, max %u(%u), depth %u(%u)", 445 inode->i_ino, error_msg, le16_to_cpu(eh->eh_magic), 446 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max), 447 max, le16_to_cpu(eh->eh_depth), depth); 448 449 return -EIO; 450 } 451 452 #define ext4_ext_check(inode, eh, depth) \ 453 __ext4_ext_check(__func__, inode, eh, depth) 454 455 int ext4_ext_check_inode(struct inode *inode) 456 { 457 return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode)); 458 } 459 460 #ifdef EXT_DEBUG 461 static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path) 462 { 463 int k, l = path->p_depth; 464 465 ext_debug("path:"); 466 for (k = 0; k <= l; k++, path++) { 467 if (path->p_idx) { 468 ext_debug(" %d->%llu", le32_to_cpu(path->p_idx->ei_block), 469 idx_pblock(path->p_idx)); 470 } else if (path->p_ext) { 471 ext_debug(" %d:[%d]%d:%llu ", 472 le32_to_cpu(path->p_ext->ee_block), 473 ext4_ext_is_uninitialized(path->p_ext), 474 ext4_ext_get_actual_len(path->p_ext), 475 ext_pblock(path->p_ext)); 476 } else 477 ext_debug(" []"); 478 } 479 ext_debug("\n"); 480 } 481 482 static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path) 483 { 484 int depth = ext_depth(inode); 485 struct ext4_extent_header *eh; 486 struct ext4_extent *ex; 487 int i; 488 489 if (!path) 490 return; 491 492 eh = path[depth].p_hdr; 493 ex = EXT_FIRST_EXTENT(eh); 494 495 ext_debug("Displaying leaf extents for inode %lu\n", inode->i_ino); 496 497 for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) { 498 ext_debug("%d:[%d]%d:%llu ", le32_to_cpu(ex->ee_block), 499 ext4_ext_is_uninitialized(ex), 500 ext4_ext_get_actual_len(ex), ext_pblock(ex)); 501 } 502 ext_debug("\n"); 503 } 504 #else 505 #define ext4_ext_show_path(inode, path) 506 #define ext4_ext_show_leaf(inode, path) 507 #endif 508 509 void ext4_ext_drop_refs(struct ext4_ext_path *path) 510 { 511 int depth = path->p_depth; 512 int i; 513 514 for (i = 0; i <= depth; i++, path++) 515 if (path->p_bh) { 516 brelse(path->p_bh); 517 path->p_bh = NULL; 518 } 519 } 520 521 /* 522 * ext4_ext_binsearch_idx: 523 * binary search for the closest index of the given block 524 * the header must be checked before calling this 525 */ 526 static void 527 ext4_ext_binsearch_idx(struct inode *inode, 528 struct ext4_ext_path *path, ext4_lblk_t block) 529 { 530 struct ext4_extent_header *eh = path->p_hdr; 531 struct ext4_extent_idx *r, *l, *m; 532 533 534 ext_debug("binsearch for %u(idx): ", block); 535 536 l = EXT_FIRST_INDEX(eh) + 1; 537 r = EXT_LAST_INDEX(eh); 538 while (l <= r) { 539 m = l + (r - l) / 2; 540 if (block < le32_to_cpu(m->ei_block)) 541 r = m - 1; 542 else 543 l = m + 1; 544 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ei_block), 545 m, le32_to_cpu(m->ei_block), 546 r, le32_to_cpu(r->ei_block)); 547 } 548 549 path->p_idx = l - 1; 550 ext_debug(" -> %d->%lld ", le32_to_cpu(path->p_idx->ei_block), 551 idx_pblock(path->p_idx)); 552 553 #ifdef CHECK_BINSEARCH 554 { 555 struct ext4_extent_idx *chix, *ix; 556 int k; 557 558 chix = ix = EXT_FIRST_INDEX(eh); 559 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) { 560 if (k != 0 && 561 le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) { 562 printk(KERN_DEBUG "k=%d, ix=0x%p, " 563 "first=0x%p\n", k, 564 ix, EXT_FIRST_INDEX(eh)); 565 printk(KERN_DEBUG "%u <= %u\n", 566 le32_to_cpu(ix->ei_block), 567 le32_to_cpu(ix[-1].ei_block)); 568 } 569 BUG_ON(k && le32_to_cpu(ix->ei_block) 570 <= le32_to_cpu(ix[-1].ei_block)); 571 if (block < le32_to_cpu(ix->ei_block)) 572 break; 573 chix = ix; 574 } 575 BUG_ON(chix != path->p_idx); 576 } 577 #endif 578 579 } 580 581 /* 582 * ext4_ext_binsearch: 583 * binary search for closest extent of the given block 584 * the header must be checked before calling this 585 */ 586 static void 587 ext4_ext_binsearch(struct inode *inode, 588 struct ext4_ext_path *path, ext4_lblk_t block) 589 { 590 struct ext4_extent_header *eh = path->p_hdr; 591 struct ext4_extent *r, *l, *m; 592 593 if (eh->eh_entries == 0) { 594 /* 595 * this leaf is empty: 596 * we get such a leaf in split/add case 597 */ 598 return; 599 } 600 601 ext_debug("binsearch for %u: ", block); 602 603 l = EXT_FIRST_EXTENT(eh) + 1; 604 r = EXT_LAST_EXTENT(eh); 605 606 while (l <= r) { 607 m = l + (r - l) / 2; 608 if (block < le32_to_cpu(m->ee_block)) 609 r = m - 1; 610 else 611 l = m + 1; 612 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ee_block), 613 m, le32_to_cpu(m->ee_block), 614 r, le32_to_cpu(r->ee_block)); 615 } 616 617 path->p_ext = l - 1; 618 ext_debug(" -> %d:%llu:[%d]%d ", 619 le32_to_cpu(path->p_ext->ee_block), 620 ext_pblock(path->p_ext), 621 ext4_ext_is_uninitialized(path->p_ext), 622 ext4_ext_get_actual_len(path->p_ext)); 623 624 #ifdef CHECK_BINSEARCH 625 { 626 struct ext4_extent *chex, *ex; 627 int k; 628 629 chex = ex = EXT_FIRST_EXTENT(eh); 630 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) { 631 BUG_ON(k && le32_to_cpu(ex->ee_block) 632 <= le32_to_cpu(ex[-1].ee_block)); 633 if (block < le32_to_cpu(ex->ee_block)) 634 break; 635 chex = ex; 636 } 637 BUG_ON(chex != path->p_ext); 638 } 639 #endif 640 641 } 642 643 int ext4_ext_tree_init(handle_t *handle, struct inode *inode) 644 { 645 struct ext4_extent_header *eh; 646 647 eh = ext_inode_hdr(inode); 648 eh->eh_depth = 0; 649 eh->eh_entries = 0; 650 eh->eh_magic = EXT4_EXT_MAGIC; 651 eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode, 0)); 652 ext4_mark_inode_dirty(handle, inode); 653 ext4_ext_invalidate_cache(inode); 654 return 0; 655 } 656 657 struct ext4_ext_path * 658 ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block, 659 struct ext4_ext_path *path) 660 { 661 struct ext4_extent_header *eh; 662 struct buffer_head *bh; 663 short int depth, i, ppos = 0, alloc = 0; 664 665 eh = ext_inode_hdr(inode); 666 depth = ext_depth(inode); 667 668 /* account possible depth increase */ 669 if (!path) { 670 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2), 671 GFP_NOFS); 672 if (!path) 673 return ERR_PTR(-ENOMEM); 674 alloc = 1; 675 } 676 path[0].p_hdr = eh; 677 path[0].p_bh = NULL; 678 679 i = depth; 680 /* walk through the tree */ 681 while (i) { 682 int need_to_validate = 0; 683 684 ext_debug("depth %d: num %d, max %d\n", 685 ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max)); 686 687 ext4_ext_binsearch_idx(inode, path + ppos, block); 688 path[ppos].p_block = idx_pblock(path[ppos].p_idx); 689 path[ppos].p_depth = i; 690 path[ppos].p_ext = NULL; 691 692 bh = sb_getblk(inode->i_sb, path[ppos].p_block); 693 if (unlikely(!bh)) 694 goto err; 695 if (!bh_uptodate_or_lock(bh)) { 696 if (bh_submit_read(bh) < 0) { 697 put_bh(bh); 698 goto err; 699 } 700 /* validate the extent entries */ 701 need_to_validate = 1; 702 } 703 eh = ext_block_hdr(bh); 704 ppos++; 705 if (unlikely(ppos > depth)) { 706 put_bh(bh); 707 EXT4_ERROR_INODE(inode, 708 "ppos %d > depth %d", ppos, depth); 709 goto err; 710 } 711 path[ppos].p_bh = bh; 712 path[ppos].p_hdr = eh; 713 i--; 714 715 if (need_to_validate && ext4_ext_check(inode, eh, i)) 716 goto err; 717 } 718 719 path[ppos].p_depth = i; 720 path[ppos].p_ext = NULL; 721 path[ppos].p_idx = NULL; 722 723 /* find extent */ 724 ext4_ext_binsearch(inode, path + ppos, block); 725 /* if not an empty leaf */ 726 if (path[ppos].p_ext) 727 path[ppos].p_block = ext_pblock(path[ppos].p_ext); 728 729 ext4_ext_show_path(inode, path); 730 731 return path; 732 733 err: 734 ext4_ext_drop_refs(path); 735 if (alloc) 736 kfree(path); 737 return ERR_PTR(-EIO); 738 } 739 740 /* 741 * ext4_ext_insert_index: 742 * insert new index [@logical;@ptr] into the block at @curp; 743 * check where to insert: before @curp or after @curp 744 */ 745 int ext4_ext_insert_index(handle_t *handle, struct inode *inode, 746 struct ext4_ext_path *curp, 747 int logical, ext4_fsblk_t ptr) 748 { 749 struct ext4_extent_idx *ix; 750 int len, err; 751 752 err = ext4_ext_get_access(handle, inode, curp); 753 if (err) 754 return err; 755 756 if (unlikely(logical == le32_to_cpu(curp->p_idx->ei_block))) { 757 EXT4_ERROR_INODE(inode, 758 "logical %d == ei_block %d!", 759 logical, le32_to_cpu(curp->p_idx->ei_block)); 760 return -EIO; 761 } 762 len = EXT_MAX_INDEX(curp->p_hdr) - curp->p_idx; 763 if (logical > le32_to_cpu(curp->p_idx->ei_block)) { 764 /* insert after */ 765 if (curp->p_idx != EXT_LAST_INDEX(curp->p_hdr)) { 766 len = (len - 1) * sizeof(struct ext4_extent_idx); 767 len = len < 0 ? 0 : len; 768 ext_debug("insert new index %d after: %llu. " 769 "move %d from 0x%p to 0x%p\n", 770 logical, ptr, len, 771 (curp->p_idx + 1), (curp->p_idx + 2)); 772 memmove(curp->p_idx + 2, curp->p_idx + 1, len); 773 } 774 ix = curp->p_idx + 1; 775 } else { 776 /* insert before */ 777 len = len * sizeof(struct ext4_extent_idx); 778 len = len < 0 ? 0 : len; 779 ext_debug("insert new index %d before: %llu. " 780 "move %d from 0x%p to 0x%p\n", 781 logical, ptr, len, 782 curp->p_idx, (curp->p_idx + 1)); 783 memmove(curp->p_idx + 1, curp->p_idx, len); 784 ix = curp->p_idx; 785 } 786 787 ix->ei_block = cpu_to_le32(logical); 788 ext4_idx_store_pblock(ix, ptr); 789 le16_add_cpu(&curp->p_hdr->eh_entries, 1); 790 791 if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries) 792 > le16_to_cpu(curp->p_hdr->eh_max))) { 793 EXT4_ERROR_INODE(inode, 794 "logical %d == ei_block %d!", 795 logical, le32_to_cpu(curp->p_idx->ei_block)); 796 return -EIO; 797 } 798 if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) { 799 EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!"); 800 return -EIO; 801 } 802 803 err = ext4_ext_dirty(handle, inode, curp); 804 ext4_std_error(inode->i_sb, err); 805 806 return err; 807 } 808 809 /* 810 * ext4_ext_split: 811 * inserts new subtree into the path, using free index entry 812 * at depth @at: 813 * - allocates all needed blocks (new leaf and all intermediate index blocks) 814 * - makes decision where to split 815 * - moves remaining extents and index entries (right to the split point) 816 * into the newly allocated blocks 817 * - initializes subtree 818 */ 819 static int ext4_ext_split(handle_t *handle, struct inode *inode, 820 struct ext4_ext_path *path, 821 struct ext4_extent *newext, int at) 822 { 823 struct buffer_head *bh = NULL; 824 int depth = ext_depth(inode); 825 struct ext4_extent_header *neh; 826 struct ext4_extent_idx *fidx; 827 struct ext4_extent *ex; 828 int i = at, k, m, a; 829 ext4_fsblk_t newblock, oldblock; 830 __le32 border; 831 ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */ 832 int err = 0; 833 834 /* make decision: where to split? */ 835 /* FIXME: now decision is simplest: at current extent */ 836 837 /* if current leaf will be split, then we should use 838 * border from split point */ 839 if (unlikely(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr))) { 840 EXT4_ERROR_INODE(inode, "p_ext > EXT_MAX_EXTENT!"); 841 return -EIO; 842 } 843 if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) { 844 border = path[depth].p_ext[1].ee_block; 845 ext_debug("leaf will be split." 846 " next leaf starts at %d\n", 847 le32_to_cpu(border)); 848 } else { 849 border = newext->ee_block; 850 ext_debug("leaf will be added." 851 " next leaf starts at %d\n", 852 le32_to_cpu(border)); 853 } 854 855 /* 856 * If error occurs, then we break processing 857 * and mark filesystem read-only. index won't 858 * be inserted and tree will be in consistent 859 * state. Next mount will repair buffers too. 860 */ 861 862 /* 863 * Get array to track all allocated blocks. 864 * We need this to handle errors and free blocks 865 * upon them. 866 */ 867 ablocks = kzalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS); 868 if (!ablocks) 869 return -ENOMEM; 870 871 /* allocate all needed blocks */ 872 ext_debug("allocate %d blocks for indexes/leaf\n", depth - at); 873 for (a = 0; a < depth - at; a++) { 874 newblock = ext4_ext_new_meta_block(handle, inode, path, 875 newext, &err); 876 if (newblock == 0) 877 goto cleanup; 878 ablocks[a] = newblock; 879 } 880 881 /* initialize new leaf */ 882 newblock = ablocks[--a]; 883 if (unlikely(newblock == 0)) { 884 EXT4_ERROR_INODE(inode, "newblock == 0!"); 885 err = -EIO; 886 goto cleanup; 887 } 888 bh = sb_getblk(inode->i_sb, newblock); 889 if (!bh) { 890 err = -EIO; 891 goto cleanup; 892 } 893 lock_buffer(bh); 894 895 err = ext4_journal_get_create_access(handle, bh); 896 if (err) 897 goto cleanup; 898 899 neh = ext_block_hdr(bh); 900 neh->eh_entries = 0; 901 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0)); 902 neh->eh_magic = EXT4_EXT_MAGIC; 903 neh->eh_depth = 0; 904 ex = EXT_FIRST_EXTENT(neh); 905 906 /* move remainder of path[depth] to the new leaf */ 907 if (unlikely(path[depth].p_hdr->eh_entries != 908 path[depth].p_hdr->eh_max)) { 909 EXT4_ERROR_INODE(inode, "eh_entries %d != eh_max %d!", 910 path[depth].p_hdr->eh_entries, 911 path[depth].p_hdr->eh_max); 912 err = -EIO; 913 goto cleanup; 914 } 915 /* start copy from next extent */ 916 /* TODO: we could do it by single memmove */ 917 m = 0; 918 path[depth].p_ext++; 919 while (path[depth].p_ext <= 920 EXT_MAX_EXTENT(path[depth].p_hdr)) { 921 ext_debug("move %d:%llu:[%d]%d in new leaf %llu\n", 922 le32_to_cpu(path[depth].p_ext->ee_block), 923 ext_pblock(path[depth].p_ext), 924 ext4_ext_is_uninitialized(path[depth].p_ext), 925 ext4_ext_get_actual_len(path[depth].p_ext), 926 newblock); 927 /*memmove(ex++, path[depth].p_ext++, 928 sizeof(struct ext4_extent)); 929 neh->eh_entries++;*/ 930 path[depth].p_ext++; 931 m++; 932 } 933 if (m) { 934 memmove(ex, path[depth].p_ext-m, sizeof(struct ext4_extent)*m); 935 le16_add_cpu(&neh->eh_entries, m); 936 } 937 938 set_buffer_uptodate(bh); 939 unlock_buffer(bh); 940 941 err = ext4_handle_dirty_metadata(handle, inode, bh); 942 if (err) 943 goto cleanup; 944 brelse(bh); 945 bh = NULL; 946 947 /* correct old leaf */ 948 if (m) { 949 err = ext4_ext_get_access(handle, inode, path + depth); 950 if (err) 951 goto cleanup; 952 le16_add_cpu(&path[depth].p_hdr->eh_entries, -m); 953 err = ext4_ext_dirty(handle, inode, path + depth); 954 if (err) 955 goto cleanup; 956 957 } 958 959 /* create intermediate indexes */ 960 k = depth - at - 1; 961 if (unlikely(k < 0)) { 962 EXT4_ERROR_INODE(inode, "k %d < 0!", k); 963 err = -EIO; 964 goto cleanup; 965 } 966 if (k) 967 ext_debug("create %d intermediate indices\n", k); 968 /* insert new index into current index block */ 969 /* current depth stored in i var */ 970 i = depth - 1; 971 while (k--) { 972 oldblock = newblock; 973 newblock = ablocks[--a]; 974 bh = sb_getblk(inode->i_sb, newblock); 975 if (!bh) { 976 err = -EIO; 977 goto cleanup; 978 } 979 lock_buffer(bh); 980 981 err = ext4_journal_get_create_access(handle, bh); 982 if (err) 983 goto cleanup; 984 985 neh = ext_block_hdr(bh); 986 neh->eh_entries = cpu_to_le16(1); 987 neh->eh_magic = EXT4_EXT_MAGIC; 988 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0)); 989 neh->eh_depth = cpu_to_le16(depth - i); 990 fidx = EXT_FIRST_INDEX(neh); 991 fidx->ei_block = border; 992 ext4_idx_store_pblock(fidx, oldblock); 993 994 ext_debug("int.index at %d (block %llu): %u -> %llu\n", 995 i, newblock, le32_to_cpu(border), oldblock); 996 /* copy indexes */ 997 m = 0; 998 path[i].p_idx++; 999 1000 ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx, 1001 EXT_MAX_INDEX(path[i].p_hdr)); 1002 if (unlikely(EXT_MAX_INDEX(path[i].p_hdr) != 1003 EXT_LAST_INDEX(path[i].p_hdr))) { 1004 EXT4_ERROR_INODE(inode, 1005 "EXT_MAX_INDEX != EXT_LAST_INDEX ee_block %d!", 1006 le32_to_cpu(path[i].p_ext->ee_block)); 1007 err = -EIO; 1008 goto cleanup; 1009 } 1010 while (path[i].p_idx <= EXT_MAX_INDEX(path[i].p_hdr)) { 1011 ext_debug("%d: move %d:%llu in new index %llu\n", i, 1012 le32_to_cpu(path[i].p_idx->ei_block), 1013 idx_pblock(path[i].p_idx), 1014 newblock); 1015 /*memmove(++fidx, path[i].p_idx++, 1016 sizeof(struct ext4_extent_idx)); 1017 neh->eh_entries++; 1018 BUG_ON(neh->eh_entries > neh->eh_max);*/ 1019 path[i].p_idx++; 1020 m++; 1021 } 1022 if (m) { 1023 memmove(++fidx, path[i].p_idx - m, 1024 sizeof(struct ext4_extent_idx) * m); 1025 le16_add_cpu(&neh->eh_entries, m); 1026 } 1027 set_buffer_uptodate(bh); 1028 unlock_buffer(bh); 1029 1030 err = ext4_handle_dirty_metadata(handle, inode, bh); 1031 if (err) 1032 goto cleanup; 1033 brelse(bh); 1034 bh = NULL; 1035 1036 /* correct old index */ 1037 if (m) { 1038 err = ext4_ext_get_access(handle, inode, path + i); 1039 if (err) 1040 goto cleanup; 1041 le16_add_cpu(&path[i].p_hdr->eh_entries, -m); 1042 err = ext4_ext_dirty(handle, inode, path + i); 1043 if (err) 1044 goto cleanup; 1045 } 1046 1047 i--; 1048 } 1049 1050 /* insert new index */ 1051 err = ext4_ext_insert_index(handle, inode, path + at, 1052 le32_to_cpu(border), newblock); 1053 1054 cleanup: 1055 if (bh) { 1056 if (buffer_locked(bh)) 1057 unlock_buffer(bh); 1058 brelse(bh); 1059 } 1060 1061 if (err) { 1062 /* free all allocated blocks in error case */ 1063 for (i = 0; i < depth; i++) { 1064 if (!ablocks[i]) 1065 continue; 1066 ext4_free_blocks(handle, inode, 0, ablocks[i], 1, 1067 EXT4_FREE_BLOCKS_METADATA); 1068 } 1069 } 1070 kfree(ablocks); 1071 1072 return err; 1073 } 1074 1075 /* 1076 * ext4_ext_grow_indepth: 1077 * implements tree growing procedure: 1078 * - allocates new block 1079 * - moves top-level data (index block or leaf) into the new block 1080 * - initializes new top-level, creating index that points to the 1081 * just created block 1082 */ 1083 static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode, 1084 struct ext4_ext_path *path, 1085 struct ext4_extent *newext) 1086 { 1087 struct ext4_ext_path *curp = path; 1088 struct ext4_extent_header *neh; 1089 struct ext4_extent_idx *fidx; 1090 struct buffer_head *bh; 1091 ext4_fsblk_t newblock; 1092 int err = 0; 1093 1094 newblock = ext4_ext_new_meta_block(handle, inode, path, newext, &err); 1095 if (newblock == 0) 1096 return err; 1097 1098 bh = sb_getblk(inode->i_sb, newblock); 1099 if (!bh) { 1100 err = -EIO; 1101 ext4_std_error(inode->i_sb, err); 1102 return err; 1103 } 1104 lock_buffer(bh); 1105 1106 err = ext4_journal_get_create_access(handle, bh); 1107 if (err) { 1108 unlock_buffer(bh); 1109 goto out; 1110 } 1111 1112 /* move top-level index/leaf into new block */ 1113 memmove(bh->b_data, curp->p_hdr, sizeof(EXT4_I(inode)->i_data)); 1114 1115 /* set size of new block */ 1116 neh = ext_block_hdr(bh); 1117 /* old root could have indexes or leaves 1118 * so calculate e_max right way */ 1119 if (ext_depth(inode)) 1120 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0)); 1121 else 1122 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0)); 1123 neh->eh_magic = EXT4_EXT_MAGIC; 1124 set_buffer_uptodate(bh); 1125 unlock_buffer(bh); 1126 1127 err = ext4_handle_dirty_metadata(handle, inode, bh); 1128 if (err) 1129 goto out; 1130 1131 /* create index in new top-level index: num,max,pointer */ 1132 err = ext4_ext_get_access(handle, inode, curp); 1133 if (err) 1134 goto out; 1135 1136 curp->p_hdr->eh_magic = EXT4_EXT_MAGIC; 1137 curp->p_hdr->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode, 0)); 1138 curp->p_hdr->eh_entries = cpu_to_le16(1); 1139 curp->p_idx = EXT_FIRST_INDEX(curp->p_hdr); 1140 1141 if (path[0].p_hdr->eh_depth) 1142 curp->p_idx->ei_block = 1143 EXT_FIRST_INDEX(path[0].p_hdr)->ei_block; 1144 else 1145 curp->p_idx->ei_block = 1146 EXT_FIRST_EXTENT(path[0].p_hdr)->ee_block; 1147 ext4_idx_store_pblock(curp->p_idx, newblock); 1148 1149 neh = ext_inode_hdr(inode); 1150 fidx = EXT_FIRST_INDEX(neh); 1151 ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n", 1152 le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max), 1153 le32_to_cpu(fidx->ei_block), idx_pblock(fidx)); 1154 1155 neh->eh_depth = cpu_to_le16(path->p_depth + 1); 1156 err = ext4_ext_dirty(handle, inode, curp); 1157 out: 1158 brelse(bh); 1159 1160 return err; 1161 } 1162 1163 /* 1164 * ext4_ext_create_new_leaf: 1165 * finds empty index and adds new leaf. 1166 * if no free index is found, then it requests in-depth growing. 1167 */ 1168 static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode, 1169 struct ext4_ext_path *path, 1170 struct ext4_extent *newext) 1171 { 1172 struct ext4_ext_path *curp; 1173 int depth, i, err = 0; 1174 1175 repeat: 1176 i = depth = ext_depth(inode); 1177 1178 /* walk up to the tree and look for free index entry */ 1179 curp = path + depth; 1180 while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) { 1181 i--; 1182 curp--; 1183 } 1184 1185 /* we use already allocated block for index block, 1186 * so subsequent data blocks should be contiguous */ 1187 if (EXT_HAS_FREE_INDEX(curp)) { 1188 /* if we found index with free entry, then use that 1189 * entry: create all needed subtree and add new leaf */ 1190 err = ext4_ext_split(handle, inode, path, newext, i); 1191 if (err) 1192 goto out; 1193 1194 /* refill path */ 1195 ext4_ext_drop_refs(path); 1196 path = ext4_ext_find_extent(inode, 1197 (ext4_lblk_t)le32_to_cpu(newext->ee_block), 1198 path); 1199 if (IS_ERR(path)) 1200 err = PTR_ERR(path); 1201 } else { 1202 /* tree is full, time to grow in depth */ 1203 err = ext4_ext_grow_indepth(handle, inode, path, newext); 1204 if (err) 1205 goto out; 1206 1207 /* refill path */ 1208 ext4_ext_drop_refs(path); 1209 path = ext4_ext_find_extent(inode, 1210 (ext4_lblk_t)le32_to_cpu(newext->ee_block), 1211 path); 1212 if (IS_ERR(path)) { 1213 err = PTR_ERR(path); 1214 goto out; 1215 } 1216 1217 /* 1218 * only first (depth 0 -> 1) produces free space; 1219 * in all other cases we have to split the grown tree 1220 */ 1221 depth = ext_depth(inode); 1222 if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) { 1223 /* now we need to split */ 1224 goto repeat; 1225 } 1226 } 1227 1228 out: 1229 return err; 1230 } 1231 1232 /* 1233 * search the closest allocated block to the left for *logical 1234 * and returns it at @logical + it's physical address at @phys 1235 * if *logical is the smallest allocated block, the function 1236 * returns 0 at @phys 1237 * return value contains 0 (success) or error code 1238 */ 1239 int 1240 ext4_ext_search_left(struct inode *inode, struct ext4_ext_path *path, 1241 ext4_lblk_t *logical, ext4_fsblk_t *phys) 1242 { 1243 struct ext4_extent_idx *ix; 1244 struct ext4_extent *ex; 1245 int depth, ee_len; 1246 1247 if (unlikely(path == NULL)) { 1248 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical); 1249 return -EIO; 1250 } 1251 depth = path->p_depth; 1252 *phys = 0; 1253 1254 if (depth == 0 && path->p_ext == NULL) 1255 return 0; 1256 1257 /* usually extent in the path covers blocks smaller 1258 * then *logical, but it can be that extent is the 1259 * first one in the file */ 1260 1261 ex = path[depth].p_ext; 1262 ee_len = ext4_ext_get_actual_len(ex); 1263 if (*logical < le32_to_cpu(ex->ee_block)) { 1264 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) { 1265 EXT4_ERROR_INODE(inode, 1266 "EXT_FIRST_EXTENT != ex *logical %d ee_block %d!", 1267 *logical, le32_to_cpu(ex->ee_block)); 1268 return -EIO; 1269 } 1270 while (--depth >= 0) { 1271 ix = path[depth].p_idx; 1272 if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) { 1273 EXT4_ERROR_INODE(inode, 1274 "ix (%d) != EXT_FIRST_INDEX (%d) (depth %d)!", 1275 ix != NULL ? ix->ei_block : 0, 1276 EXT_FIRST_INDEX(path[depth].p_hdr) != NULL ? 1277 EXT_FIRST_INDEX(path[depth].p_hdr)->ei_block : 0, 1278 depth); 1279 return -EIO; 1280 } 1281 } 1282 return 0; 1283 } 1284 1285 if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) { 1286 EXT4_ERROR_INODE(inode, 1287 "logical %d < ee_block %d + ee_len %d!", 1288 *logical, le32_to_cpu(ex->ee_block), ee_len); 1289 return -EIO; 1290 } 1291 1292 *logical = le32_to_cpu(ex->ee_block) + ee_len - 1; 1293 *phys = ext_pblock(ex) + ee_len - 1; 1294 return 0; 1295 } 1296 1297 /* 1298 * search the closest allocated block to the right for *logical 1299 * and returns it at @logical + it's physical address at @phys 1300 * if *logical is the smallest allocated block, the function 1301 * returns 0 at @phys 1302 * return value contains 0 (success) or error code 1303 */ 1304 int 1305 ext4_ext_search_right(struct inode *inode, struct ext4_ext_path *path, 1306 ext4_lblk_t *logical, ext4_fsblk_t *phys) 1307 { 1308 struct buffer_head *bh = NULL; 1309 struct ext4_extent_header *eh; 1310 struct ext4_extent_idx *ix; 1311 struct ext4_extent *ex; 1312 ext4_fsblk_t block; 1313 int depth; /* Note, NOT eh_depth; depth from top of tree */ 1314 int ee_len; 1315 1316 if (unlikely(path == NULL)) { 1317 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical); 1318 return -EIO; 1319 } 1320 depth = path->p_depth; 1321 *phys = 0; 1322 1323 if (depth == 0 && path->p_ext == NULL) 1324 return 0; 1325 1326 /* usually extent in the path covers blocks smaller 1327 * then *logical, but it can be that extent is the 1328 * first one in the file */ 1329 1330 ex = path[depth].p_ext; 1331 ee_len = ext4_ext_get_actual_len(ex); 1332 if (*logical < le32_to_cpu(ex->ee_block)) { 1333 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) { 1334 EXT4_ERROR_INODE(inode, 1335 "first_extent(path[%d].p_hdr) != ex", 1336 depth); 1337 return -EIO; 1338 } 1339 while (--depth >= 0) { 1340 ix = path[depth].p_idx; 1341 if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) { 1342 EXT4_ERROR_INODE(inode, 1343 "ix != EXT_FIRST_INDEX *logical %d!", 1344 *logical); 1345 return -EIO; 1346 } 1347 } 1348 *logical = le32_to_cpu(ex->ee_block); 1349 *phys = ext_pblock(ex); 1350 return 0; 1351 } 1352 1353 if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) { 1354 EXT4_ERROR_INODE(inode, 1355 "logical %d < ee_block %d + ee_len %d!", 1356 *logical, le32_to_cpu(ex->ee_block), ee_len); 1357 return -EIO; 1358 } 1359 1360 if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) { 1361 /* next allocated block in this leaf */ 1362 ex++; 1363 *logical = le32_to_cpu(ex->ee_block); 1364 *phys = ext_pblock(ex); 1365 return 0; 1366 } 1367 1368 /* go up and search for index to the right */ 1369 while (--depth >= 0) { 1370 ix = path[depth].p_idx; 1371 if (ix != EXT_LAST_INDEX(path[depth].p_hdr)) 1372 goto got_index; 1373 } 1374 1375 /* we've gone up to the root and found no index to the right */ 1376 return 0; 1377 1378 got_index: 1379 /* we've found index to the right, let's 1380 * follow it and find the closest allocated 1381 * block to the right */ 1382 ix++; 1383 block = idx_pblock(ix); 1384 while (++depth < path->p_depth) { 1385 bh = sb_bread(inode->i_sb, block); 1386 if (bh == NULL) 1387 return -EIO; 1388 eh = ext_block_hdr(bh); 1389 /* subtract from p_depth to get proper eh_depth */ 1390 if (ext4_ext_check(inode, eh, path->p_depth - depth)) { 1391 put_bh(bh); 1392 return -EIO; 1393 } 1394 ix = EXT_FIRST_INDEX(eh); 1395 block = idx_pblock(ix); 1396 put_bh(bh); 1397 } 1398 1399 bh = sb_bread(inode->i_sb, block); 1400 if (bh == NULL) 1401 return -EIO; 1402 eh = ext_block_hdr(bh); 1403 if (ext4_ext_check(inode, eh, path->p_depth - depth)) { 1404 put_bh(bh); 1405 return -EIO; 1406 } 1407 ex = EXT_FIRST_EXTENT(eh); 1408 *logical = le32_to_cpu(ex->ee_block); 1409 *phys = ext_pblock(ex); 1410 put_bh(bh); 1411 return 0; 1412 } 1413 1414 /* 1415 * ext4_ext_next_allocated_block: 1416 * returns allocated block in subsequent extent or EXT_MAX_BLOCK. 1417 * NOTE: it considers block number from index entry as 1418 * allocated block. Thus, index entries have to be consistent 1419 * with leaves. 1420 */ 1421 static ext4_lblk_t 1422 ext4_ext_next_allocated_block(struct ext4_ext_path *path) 1423 { 1424 int depth; 1425 1426 BUG_ON(path == NULL); 1427 depth = path->p_depth; 1428 1429 if (depth == 0 && path->p_ext == NULL) 1430 return EXT_MAX_BLOCK; 1431 1432 while (depth >= 0) { 1433 if (depth == path->p_depth) { 1434 /* leaf */ 1435 if (path[depth].p_ext != 1436 EXT_LAST_EXTENT(path[depth].p_hdr)) 1437 return le32_to_cpu(path[depth].p_ext[1].ee_block); 1438 } else { 1439 /* index */ 1440 if (path[depth].p_idx != 1441 EXT_LAST_INDEX(path[depth].p_hdr)) 1442 return le32_to_cpu(path[depth].p_idx[1].ei_block); 1443 } 1444 depth--; 1445 } 1446 1447 return EXT_MAX_BLOCK; 1448 } 1449 1450 /* 1451 * ext4_ext_next_leaf_block: 1452 * returns first allocated block from next leaf or EXT_MAX_BLOCK 1453 */ 1454 static ext4_lblk_t ext4_ext_next_leaf_block(struct inode *inode, 1455 struct ext4_ext_path *path) 1456 { 1457 int depth; 1458 1459 BUG_ON(path == NULL); 1460 depth = path->p_depth; 1461 1462 /* zero-tree has no leaf blocks at all */ 1463 if (depth == 0) 1464 return EXT_MAX_BLOCK; 1465 1466 /* go to index block */ 1467 depth--; 1468 1469 while (depth >= 0) { 1470 if (path[depth].p_idx != 1471 EXT_LAST_INDEX(path[depth].p_hdr)) 1472 return (ext4_lblk_t) 1473 le32_to_cpu(path[depth].p_idx[1].ei_block); 1474 depth--; 1475 } 1476 1477 return EXT_MAX_BLOCK; 1478 } 1479 1480 /* 1481 * ext4_ext_correct_indexes: 1482 * if leaf gets modified and modified extent is first in the leaf, 1483 * then we have to correct all indexes above. 1484 * TODO: do we need to correct tree in all cases? 1485 */ 1486 static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode, 1487 struct ext4_ext_path *path) 1488 { 1489 struct ext4_extent_header *eh; 1490 int depth = ext_depth(inode); 1491 struct ext4_extent *ex; 1492 __le32 border; 1493 int k, err = 0; 1494 1495 eh = path[depth].p_hdr; 1496 ex = path[depth].p_ext; 1497 1498 if (unlikely(ex == NULL || eh == NULL)) { 1499 EXT4_ERROR_INODE(inode, 1500 "ex %p == NULL or eh %p == NULL", ex, eh); 1501 return -EIO; 1502 } 1503 1504 if (depth == 0) { 1505 /* there is no tree at all */ 1506 return 0; 1507 } 1508 1509 if (ex != EXT_FIRST_EXTENT(eh)) { 1510 /* we correct tree if first leaf got modified only */ 1511 return 0; 1512 } 1513 1514 /* 1515 * TODO: we need correction if border is smaller than current one 1516 */ 1517 k = depth - 1; 1518 border = path[depth].p_ext->ee_block; 1519 err = ext4_ext_get_access(handle, inode, path + k); 1520 if (err) 1521 return err; 1522 path[k].p_idx->ei_block = border; 1523 err = ext4_ext_dirty(handle, inode, path + k); 1524 if (err) 1525 return err; 1526 1527 while (k--) { 1528 /* change all left-side indexes */ 1529 if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr)) 1530 break; 1531 err = ext4_ext_get_access(handle, inode, path + k); 1532 if (err) 1533 break; 1534 path[k].p_idx->ei_block = border; 1535 err = ext4_ext_dirty(handle, inode, path + k); 1536 if (err) 1537 break; 1538 } 1539 1540 return err; 1541 } 1542 1543 int 1544 ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1, 1545 struct ext4_extent *ex2) 1546 { 1547 unsigned short ext1_ee_len, ext2_ee_len, max_len; 1548 1549 /* 1550 * Make sure that either both extents are uninitialized, or 1551 * both are _not_. 1552 */ 1553 if (ext4_ext_is_uninitialized(ex1) ^ ext4_ext_is_uninitialized(ex2)) 1554 return 0; 1555 1556 if (ext4_ext_is_uninitialized(ex1)) 1557 max_len = EXT_UNINIT_MAX_LEN; 1558 else 1559 max_len = EXT_INIT_MAX_LEN; 1560 1561 ext1_ee_len = ext4_ext_get_actual_len(ex1); 1562 ext2_ee_len = ext4_ext_get_actual_len(ex2); 1563 1564 if (le32_to_cpu(ex1->ee_block) + ext1_ee_len != 1565 le32_to_cpu(ex2->ee_block)) 1566 return 0; 1567 1568 /* 1569 * To allow future support for preallocated extents to be added 1570 * as an RO_COMPAT feature, refuse to merge to extents if 1571 * this can result in the top bit of ee_len being set. 1572 */ 1573 if (ext1_ee_len + ext2_ee_len > max_len) 1574 return 0; 1575 #ifdef AGGRESSIVE_TEST 1576 if (ext1_ee_len >= 4) 1577 return 0; 1578 #endif 1579 1580 if (ext_pblock(ex1) + ext1_ee_len == ext_pblock(ex2)) 1581 return 1; 1582 return 0; 1583 } 1584 1585 /* 1586 * This function tries to merge the "ex" extent to the next extent in the tree. 1587 * It always tries to merge towards right. If you want to merge towards 1588 * left, pass "ex - 1" as argument instead of "ex". 1589 * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns 1590 * 1 if they got merged. 1591 */ 1592 int ext4_ext_try_to_merge(struct inode *inode, 1593 struct ext4_ext_path *path, 1594 struct ext4_extent *ex) 1595 { 1596 struct ext4_extent_header *eh; 1597 unsigned int depth, len; 1598 int merge_done = 0; 1599 int uninitialized = 0; 1600 1601 depth = ext_depth(inode); 1602 BUG_ON(path[depth].p_hdr == NULL); 1603 eh = path[depth].p_hdr; 1604 1605 while (ex < EXT_LAST_EXTENT(eh)) { 1606 if (!ext4_can_extents_be_merged(inode, ex, ex + 1)) 1607 break; 1608 /* merge with next extent! */ 1609 if (ext4_ext_is_uninitialized(ex)) 1610 uninitialized = 1; 1611 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex) 1612 + ext4_ext_get_actual_len(ex + 1)); 1613 if (uninitialized) 1614 ext4_ext_mark_uninitialized(ex); 1615 1616 if (ex + 1 < EXT_LAST_EXTENT(eh)) { 1617 len = (EXT_LAST_EXTENT(eh) - ex - 1) 1618 * sizeof(struct ext4_extent); 1619 memmove(ex + 1, ex + 2, len); 1620 } 1621 le16_add_cpu(&eh->eh_entries, -1); 1622 merge_done = 1; 1623 WARN_ON(eh->eh_entries == 0); 1624 if (!eh->eh_entries) 1625 ext4_error(inode->i_sb, 1626 "inode#%lu, eh->eh_entries = 0!", 1627 inode->i_ino); 1628 } 1629 1630 return merge_done; 1631 } 1632 1633 /* 1634 * check if a portion of the "newext" extent overlaps with an 1635 * existing extent. 1636 * 1637 * If there is an overlap discovered, it updates the length of the newext 1638 * such that there will be no overlap, and then returns 1. 1639 * If there is no overlap found, it returns 0. 1640 */ 1641 unsigned int ext4_ext_check_overlap(struct inode *inode, 1642 struct ext4_extent *newext, 1643 struct ext4_ext_path *path) 1644 { 1645 ext4_lblk_t b1, b2; 1646 unsigned int depth, len1; 1647 unsigned int ret = 0; 1648 1649 b1 = le32_to_cpu(newext->ee_block); 1650 len1 = ext4_ext_get_actual_len(newext); 1651 depth = ext_depth(inode); 1652 if (!path[depth].p_ext) 1653 goto out; 1654 b2 = le32_to_cpu(path[depth].p_ext->ee_block); 1655 1656 /* 1657 * get the next allocated block if the extent in the path 1658 * is before the requested block(s) 1659 */ 1660 if (b2 < b1) { 1661 b2 = ext4_ext_next_allocated_block(path); 1662 if (b2 == EXT_MAX_BLOCK) 1663 goto out; 1664 } 1665 1666 /* check for wrap through zero on extent logical start block*/ 1667 if (b1 + len1 < b1) { 1668 len1 = EXT_MAX_BLOCK - b1; 1669 newext->ee_len = cpu_to_le16(len1); 1670 ret = 1; 1671 } 1672 1673 /* check for overlap */ 1674 if (b1 + len1 > b2) { 1675 newext->ee_len = cpu_to_le16(b2 - b1); 1676 ret = 1; 1677 } 1678 out: 1679 return ret; 1680 } 1681 1682 /* 1683 * ext4_ext_insert_extent: 1684 * tries to merge requsted extent into the existing extent or 1685 * inserts requested extent as new one into the tree, 1686 * creating new leaf in the no-space case. 1687 */ 1688 int ext4_ext_insert_extent(handle_t *handle, struct inode *inode, 1689 struct ext4_ext_path *path, 1690 struct ext4_extent *newext, int flag) 1691 { 1692 struct ext4_extent_header *eh; 1693 struct ext4_extent *ex, *fex; 1694 struct ext4_extent *nearex; /* nearest extent */ 1695 struct ext4_ext_path *npath = NULL; 1696 int depth, len, err; 1697 ext4_lblk_t next; 1698 unsigned uninitialized = 0; 1699 1700 if (unlikely(ext4_ext_get_actual_len(newext) == 0)) { 1701 EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0"); 1702 return -EIO; 1703 } 1704 depth = ext_depth(inode); 1705 ex = path[depth].p_ext; 1706 if (unlikely(path[depth].p_hdr == NULL)) { 1707 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth); 1708 return -EIO; 1709 } 1710 1711 /* try to insert block into found extent and return */ 1712 if (ex && !(flag & EXT4_GET_BLOCKS_PRE_IO) 1713 && ext4_can_extents_be_merged(inode, ex, newext)) { 1714 ext_debug("append [%d]%d block to %d:[%d]%d (from %llu)\n", 1715 ext4_ext_is_uninitialized(newext), 1716 ext4_ext_get_actual_len(newext), 1717 le32_to_cpu(ex->ee_block), 1718 ext4_ext_is_uninitialized(ex), 1719 ext4_ext_get_actual_len(ex), ext_pblock(ex)); 1720 err = ext4_ext_get_access(handle, inode, path + depth); 1721 if (err) 1722 return err; 1723 1724 /* 1725 * ext4_can_extents_be_merged should have checked that either 1726 * both extents are uninitialized, or both aren't. Thus we 1727 * need to check only one of them here. 1728 */ 1729 if (ext4_ext_is_uninitialized(ex)) 1730 uninitialized = 1; 1731 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex) 1732 + ext4_ext_get_actual_len(newext)); 1733 if (uninitialized) 1734 ext4_ext_mark_uninitialized(ex); 1735 eh = path[depth].p_hdr; 1736 nearex = ex; 1737 goto merge; 1738 } 1739 1740 repeat: 1741 depth = ext_depth(inode); 1742 eh = path[depth].p_hdr; 1743 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) 1744 goto has_space; 1745 1746 /* probably next leaf has space for us? */ 1747 fex = EXT_LAST_EXTENT(eh); 1748 next = ext4_ext_next_leaf_block(inode, path); 1749 if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block) 1750 && next != EXT_MAX_BLOCK) { 1751 ext_debug("next leaf block - %d\n", next); 1752 BUG_ON(npath != NULL); 1753 npath = ext4_ext_find_extent(inode, next, NULL); 1754 if (IS_ERR(npath)) 1755 return PTR_ERR(npath); 1756 BUG_ON(npath->p_depth != path->p_depth); 1757 eh = npath[depth].p_hdr; 1758 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) { 1759 ext_debug("next leaf isnt full(%d)\n", 1760 le16_to_cpu(eh->eh_entries)); 1761 path = npath; 1762 goto repeat; 1763 } 1764 ext_debug("next leaf has no free space(%d,%d)\n", 1765 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max)); 1766 } 1767 1768 /* 1769 * There is no free space in the found leaf. 1770 * We're gonna add a new leaf in the tree. 1771 */ 1772 err = ext4_ext_create_new_leaf(handle, inode, path, newext); 1773 if (err) 1774 goto cleanup; 1775 depth = ext_depth(inode); 1776 eh = path[depth].p_hdr; 1777 1778 has_space: 1779 nearex = path[depth].p_ext; 1780 1781 err = ext4_ext_get_access(handle, inode, path + depth); 1782 if (err) 1783 goto cleanup; 1784 1785 if (!nearex) { 1786 /* there is no extent in this leaf, create first one */ 1787 ext_debug("first extent in the leaf: %d:%llu:[%d]%d\n", 1788 le32_to_cpu(newext->ee_block), 1789 ext_pblock(newext), 1790 ext4_ext_is_uninitialized(newext), 1791 ext4_ext_get_actual_len(newext)); 1792 path[depth].p_ext = EXT_FIRST_EXTENT(eh); 1793 } else if (le32_to_cpu(newext->ee_block) 1794 > le32_to_cpu(nearex->ee_block)) { 1795 /* BUG_ON(newext->ee_block == nearex->ee_block); */ 1796 if (nearex != EXT_LAST_EXTENT(eh)) { 1797 len = EXT_MAX_EXTENT(eh) - nearex; 1798 len = (len - 1) * sizeof(struct ext4_extent); 1799 len = len < 0 ? 0 : len; 1800 ext_debug("insert %d:%llu:[%d]%d after: nearest 0x%p, " 1801 "move %d from 0x%p to 0x%p\n", 1802 le32_to_cpu(newext->ee_block), 1803 ext_pblock(newext), 1804 ext4_ext_is_uninitialized(newext), 1805 ext4_ext_get_actual_len(newext), 1806 nearex, len, nearex + 1, nearex + 2); 1807 memmove(nearex + 2, nearex + 1, len); 1808 } 1809 path[depth].p_ext = nearex + 1; 1810 } else { 1811 BUG_ON(newext->ee_block == nearex->ee_block); 1812 len = (EXT_MAX_EXTENT(eh) - nearex) * sizeof(struct ext4_extent); 1813 len = len < 0 ? 0 : len; 1814 ext_debug("insert %d:%llu:[%d]%d before: nearest 0x%p, " 1815 "move %d from 0x%p to 0x%p\n", 1816 le32_to_cpu(newext->ee_block), 1817 ext_pblock(newext), 1818 ext4_ext_is_uninitialized(newext), 1819 ext4_ext_get_actual_len(newext), 1820 nearex, len, nearex + 1, nearex + 2); 1821 memmove(nearex + 1, nearex, len); 1822 path[depth].p_ext = nearex; 1823 } 1824 1825 le16_add_cpu(&eh->eh_entries, 1); 1826 nearex = path[depth].p_ext; 1827 nearex->ee_block = newext->ee_block; 1828 ext4_ext_store_pblock(nearex, ext_pblock(newext)); 1829 nearex->ee_len = newext->ee_len; 1830 1831 merge: 1832 /* try to merge extents to the right */ 1833 if (!(flag & EXT4_GET_BLOCKS_PRE_IO)) 1834 ext4_ext_try_to_merge(inode, path, nearex); 1835 1836 /* try to merge extents to the left */ 1837 1838 /* time to correct all indexes above */ 1839 err = ext4_ext_correct_indexes(handle, inode, path); 1840 if (err) 1841 goto cleanup; 1842 1843 err = ext4_ext_dirty(handle, inode, path + depth); 1844 1845 cleanup: 1846 if (npath) { 1847 ext4_ext_drop_refs(npath); 1848 kfree(npath); 1849 } 1850 ext4_ext_invalidate_cache(inode); 1851 return err; 1852 } 1853 1854 int ext4_ext_walk_space(struct inode *inode, ext4_lblk_t block, 1855 ext4_lblk_t num, ext_prepare_callback func, 1856 void *cbdata) 1857 { 1858 struct ext4_ext_path *path = NULL; 1859 struct ext4_ext_cache cbex; 1860 struct ext4_extent *ex; 1861 ext4_lblk_t next, start = 0, end = 0; 1862 ext4_lblk_t last = block + num; 1863 int depth, exists, err = 0; 1864 1865 BUG_ON(func == NULL); 1866 BUG_ON(inode == NULL); 1867 1868 while (block < last && block != EXT_MAX_BLOCK) { 1869 num = last - block; 1870 /* find extent for this block */ 1871 down_read(&EXT4_I(inode)->i_data_sem); 1872 path = ext4_ext_find_extent(inode, block, path); 1873 up_read(&EXT4_I(inode)->i_data_sem); 1874 if (IS_ERR(path)) { 1875 err = PTR_ERR(path); 1876 path = NULL; 1877 break; 1878 } 1879 1880 depth = ext_depth(inode); 1881 if (unlikely(path[depth].p_hdr == NULL)) { 1882 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth); 1883 err = -EIO; 1884 break; 1885 } 1886 ex = path[depth].p_ext; 1887 next = ext4_ext_next_allocated_block(path); 1888 1889 exists = 0; 1890 if (!ex) { 1891 /* there is no extent yet, so try to allocate 1892 * all requested space */ 1893 start = block; 1894 end = block + num; 1895 } else if (le32_to_cpu(ex->ee_block) > block) { 1896 /* need to allocate space before found extent */ 1897 start = block; 1898 end = le32_to_cpu(ex->ee_block); 1899 if (block + num < end) 1900 end = block + num; 1901 } else if (block >= le32_to_cpu(ex->ee_block) 1902 + ext4_ext_get_actual_len(ex)) { 1903 /* need to allocate space after found extent */ 1904 start = block; 1905 end = block + num; 1906 if (end >= next) 1907 end = next; 1908 } else if (block >= le32_to_cpu(ex->ee_block)) { 1909 /* 1910 * some part of requested space is covered 1911 * by found extent 1912 */ 1913 start = block; 1914 end = le32_to_cpu(ex->ee_block) 1915 + ext4_ext_get_actual_len(ex); 1916 if (block + num < end) 1917 end = block + num; 1918 exists = 1; 1919 } else { 1920 BUG(); 1921 } 1922 BUG_ON(end <= start); 1923 1924 if (!exists) { 1925 cbex.ec_block = start; 1926 cbex.ec_len = end - start; 1927 cbex.ec_start = 0; 1928 cbex.ec_type = EXT4_EXT_CACHE_GAP; 1929 } else { 1930 cbex.ec_block = le32_to_cpu(ex->ee_block); 1931 cbex.ec_len = ext4_ext_get_actual_len(ex); 1932 cbex.ec_start = ext_pblock(ex); 1933 cbex.ec_type = EXT4_EXT_CACHE_EXTENT; 1934 } 1935 1936 if (unlikely(cbex.ec_len == 0)) { 1937 EXT4_ERROR_INODE(inode, "cbex.ec_len == 0"); 1938 err = -EIO; 1939 break; 1940 } 1941 err = func(inode, path, &cbex, ex, cbdata); 1942 ext4_ext_drop_refs(path); 1943 1944 if (err < 0) 1945 break; 1946 1947 if (err == EXT_REPEAT) 1948 continue; 1949 else if (err == EXT_BREAK) { 1950 err = 0; 1951 break; 1952 } 1953 1954 if (ext_depth(inode) != depth) { 1955 /* depth was changed. we have to realloc path */ 1956 kfree(path); 1957 path = NULL; 1958 } 1959 1960 block = cbex.ec_block + cbex.ec_len; 1961 } 1962 1963 if (path) { 1964 ext4_ext_drop_refs(path); 1965 kfree(path); 1966 } 1967 1968 return err; 1969 } 1970 1971 static void 1972 ext4_ext_put_in_cache(struct inode *inode, ext4_lblk_t block, 1973 __u32 len, ext4_fsblk_t start, int type) 1974 { 1975 struct ext4_ext_cache *cex; 1976 BUG_ON(len == 0); 1977 spin_lock(&EXT4_I(inode)->i_block_reservation_lock); 1978 cex = &EXT4_I(inode)->i_cached_extent; 1979 cex->ec_type = type; 1980 cex->ec_block = block; 1981 cex->ec_len = len; 1982 cex->ec_start = start; 1983 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock); 1984 } 1985 1986 /* 1987 * ext4_ext_put_gap_in_cache: 1988 * calculate boundaries of the gap that the requested block fits into 1989 * and cache this gap 1990 */ 1991 static void 1992 ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path, 1993 ext4_lblk_t block) 1994 { 1995 int depth = ext_depth(inode); 1996 unsigned long len; 1997 ext4_lblk_t lblock; 1998 struct ext4_extent *ex; 1999 2000 ex = path[depth].p_ext; 2001 if (ex == NULL) { 2002 /* there is no extent yet, so gap is [0;-] */ 2003 lblock = 0; 2004 len = EXT_MAX_BLOCK; 2005 ext_debug("cache gap(whole file):"); 2006 } else if (block < le32_to_cpu(ex->ee_block)) { 2007 lblock = block; 2008 len = le32_to_cpu(ex->ee_block) - block; 2009 ext_debug("cache gap(before): %u [%u:%u]", 2010 block, 2011 le32_to_cpu(ex->ee_block), 2012 ext4_ext_get_actual_len(ex)); 2013 } else if (block >= le32_to_cpu(ex->ee_block) 2014 + ext4_ext_get_actual_len(ex)) { 2015 ext4_lblk_t next; 2016 lblock = le32_to_cpu(ex->ee_block) 2017 + ext4_ext_get_actual_len(ex); 2018 2019 next = ext4_ext_next_allocated_block(path); 2020 ext_debug("cache gap(after): [%u:%u] %u", 2021 le32_to_cpu(ex->ee_block), 2022 ext4_ext_get_actual_len(ex), 2023 block); 2024 BUG_ON(next == lblock); 2025 len = next - lblock; 2026 } else { 2027 lblock = len = 0; 2028 BUG(); 2029 } 2030 2031 ext_debug(" -> %u:%lu\n", lblock, len); 2032 ext4_ext_put_in_cache(inode, lblock, len, 0, EXT4_EXT_CACHE_GAP); 2033 } 2034 2035 static int 2036 ext4_ext_in_cache(struct inode *inode, ext4_lblk_t block, 2037 struct ext4_extent *ex) 2038 { 2039 struct ext4_ext_cache *cex; 2040 int ret = EXT4_EXT_CACHE_NO; 2041 2042 /* 2043 * We borrow i_block_reservation_lock to protect i_cached_extent 2044 */ 2045 spin_lock(&EXT4_I(inode)->i_block_reservation_lock); 2046 cex = &EXT4_I(inode)->i_cached_extent; 2047 2048 /* has cache valid data? */ 2049 if (cex->ec_type == EXT4_EXT_CACHE_NO) 2050 goto errout; 2051 2052 BUG_ON(cex->ec_type != EXT4_EXT_CACHE_GAP && 2053 cex->ec_type != EXT4_EXT_CACHE_EXTENT); 2054 if (in_range(block, cex->ec_block, cex->ec_len)) { 2055 ex->ee_block = cpu_to_le32(cex->ec_block); 2056 ext4_ext_store_pblock(ex, cex->ec_start); 2057 ex->ee_len = cpu_to_le16(cex->ec_len); 2058 ext_debug("%u cached by %u:%u:%llu\n", 2059 block, 2060 cex->ec_block, cex->ec_len, cex->ec_start); 2061 ret = cex->ec_type; 2062 } 2063 errout: 2064 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock); 2065 return ret; 2066 } 2067 2068 /* 2069 * ext4_ext_rm_idx: 2070 * removes index from the index block. 2071 * It's used in truncate case only, thus all requests are for 2072 * last index in the block only. 2073 */ 2074 static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode, 2075 struct ext4_ext_path *path) 2076 { 2077 int err; 2078 ext4_fsblk_t leaf; 2079 2080 /* free index block */ 2081 path--; 2082 leaf = idx_pblock(path->p_idx); 2083 if (unlikely(path->p_hdr->eh_entries == 0)) { 2084 EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0"); 2085 return -EIO; 2086 } 2087 err = ext4_ext_get_access(handle, inode, path); 2088 if (err) 2089 return err; 2090 le16_add_cpu(&path->p_hdr->eh_entries, -1); 2091 err = ext4_ext_dirty(handle, inode, path); 2092 if (err) 2093 return err; 2094 ext_debug("index is empty, remove it, free block %llu\n", leaf); 2095 ext4_free_blocks(handle, inode, 0, leaf, 1, 2096 EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET); 2097 return err; 2098 } 2099 2100 /* 2101 * ext4_ext_calc_credits_for_single_extent: 2102 * This routine returns max. credits that needed to insert an extent 2103 * to the extent tree. 2104 * When pass the actual path, the caller should calculate credits 2105 * under i_data_sem. 2106 */ 2107 int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks, 2108 struct ext4_ext_path *path) 2109 { 2110 if (path) { 2111 int depth = ext_depth(inode); 2112 int ret = 0; 2113 2114 /* probably there is space in leaf? */ 2115 if (le16_to_cpu(path[depth].p_hdr->eh_entries) 2116 < le16_to_cpu(path[depth].p_hdr->eh_max)) { 2117 2118 /* 2119 * There are some space in the leaf tree, no 2120 * need to account for leaf block credit 2121 * 2122 * bitmaps and block group descriptor blocks 2123 * and other metadat blocks still need to be 2124 * accounted. 2125 */ 2126 /* 1 bitmap, 1 block group descriptor */ 2127 ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb); 2128 return ret; 2129 } 2130 } 2131 2132 return ext4_chunk_trans_blocks(inode, nrblocks); 2133 } 2134 2135 /* 2136 * How many index/leaf blocks need to change/allocate to modify nrblocks? 2137 * 2138 * if nrblocks are fit in a single extent (chunk flag is 1), then 2139 * in the worse case, each tree level index/leaf need to be changed 2140 * if the tree split due to insert a new extent, then the old tree 2141 * index/leaf need to be updated too 2142 * 2143 * If the nrblocks are discontiguous, they could cause 2144 * the whole tree split more than once, but this is really rare. 2145 */ 2146 int ext4_ext_index_trans_blocks(struct inode *inode, int nrblocks, int chunk) 2147 { 2148 int index; 2149 int depth = ext_depth(inode); 2150 2151 if (chunk) 2152 index = depth * 2; 2153 else 2154 index = depth * 3; 2155 2156 return index; 2157 } 2158 2159 static int ext4_remove_blocks(handle_t *handle, struct inode *inode, 2160 struct ext4_extent *ex, 2161 ext4_lblk_t from, ext4_lblk_t to) 2162 { 2163 unsigned short ee_len = ext4_ext_get_actual_len(ex); 2164 int flags = EXT4_FREE_BLOCKS_FORGET; 2165 2166 if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) 2167 flags |= EXT4_FREE_BLOCKS_METADATA; 2168 #ifdef EXTENTS_STATS 2169 { 2170 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 2171 spin_lock(&sbi->s_ext_stats_lock); 2172 sbi->s_ext_blocks += ee_len; 2173 sbi->s_ext_extents++; 2174 if (ee_len < sbi->s_ext_min) 2175 sbi->s_ext_min = ee_len; 2176 if (ee_len > sbi->s_ext_max) 2177 sbi->s_ext_max = ee_len; 2178 if (ext_depth(inode) > sbi->s_depth_max) 2179 sbi->s_depth_max = ext_depth(inode); 2180 spin_unlock(&sbi->s_ext_stats_lock); 2181 } 2182 #endif 2183 if (from >= le32_to_cpu(ex->ee_block) 2184 && to == le32_to_cpu(ex->ee_block) + ee_len - 1) { 2185 /* tail removal */ 2186 ext4_lblk_t num; 2187 ext4_fsblk_t start; 2188 2189 num = le32_to_cpu(ex->ee_block) + ee_len - from; 2190 start = ext_pblock(ex) + ee_len - num; 2191 ext_debug("free last %u blocks starting %llu\n", num, start); 2192 ext4_free_blocks(handle, inode, 0, start, num, flags); 2193 } else if (from == le32_to_cpu(ex->ee_block) 2194 && to <= le32_to_cpu(ex->ee_block) + ee_len - 1) { 2195 printk(KERN_INFO "strange request: removal %u-%u from %u:%u\n", 2196 from, to, le32_to_cpu(ex->ee_block), ee_len); 2197 } else { 2198 printk(KERN_INFO "strange request: removal(2) " 2199 "%u-%u from %u:%u\n", 2200 from, to, le32_to_cpu(ex->ee_block), ee_len); 2201 } 2202 return 0; 2203 } 2204 2205 static int 2206 ext4_ext_rm_leaf(handle_t *handle, struct inode *inode, 2207 struct ext4_ext_path *path, ext4_lblk_t start) 2208 { 2209 int err = 0, correct_index = 0; 2210 int depth = ext_depth(inode), credits; 2211 struct ext4_extent_header *eh; 2212 ext4_lblk_t a, b, block; 2213 unsigned num; 2214 ext4_lblk_t ex_ee_block; 2215 unsigned short ex_ee_len; 2216 unsigned uninitialized = 0; 2217 struct ext4_extent *ex; 2218 2219 /* the header must be checked already in ext4_ext_remove_space() */ 2220 ext_debug("truncate since %u in leaf\n", start); 2221 if (!path[depth].p_hdr) 2222 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh); 2223 eh = path[depth].p_hdr; 2224 if (unlikely(path[depth].p_hdr == NULL)) { 2225 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth); 2226 return -EIO; 2227 } 2228 /* find where to start removing */ 2229 ex = EXT_LAST_EXTENT(eh); 2230 2231 ex_ee_block = le32_to_cpu(ex->ee_block); 2232 ex_ee_len = ext4_ext_get_actual_len(ex); 2233 2234 while (ex >= EXT_FIRST_EXTENT(eh) && 2235 ex_ee_block + ex_ee_len > start) { 2236 2237 if (ext4_ext_is_uninitialized(ex)) 2238 uninitialized = 1; 2239 else 2240 uninitialized = 0; 2241 2242 ext_debug("remove ext %u:[%d]%d\n", ex_ee_block, 2243 uninitialized, ex_ee_len); 2244 path[depth].p_ext = ex; 2245 2246 a = ex_ee_block > start ? ex_ee_block : start; 2247 b = ex_ee_block + ex_ee_len - 1 < EXT_MAX_BLOCK ? 2248 ex_ee_block + ex_ee_len - 1 : EXT_MAX_BLOCK; 2249 2250 ext_debug(" border %u:%u\n", a, b); 2251 2252 if (a != ex_ee_block && b != ex_ee_block + ex_ee_len - 1) { 2253 block = 0; 2254 num = 0; 2255 BUG(); 2256 } else if (a != ex_ee_block) { 2257 /* remove tail of the extent */ 2258 block = ex_ee_block; 2259 num = a - block; 2260 } else if (b != ex_ee_block + ex_ee_len - 1) { 2261 /* remove head of the extent */ 2262 block = a; 2263 num = b - a; 2264 /* there is no "make a hole" API yet */ 2265 BUG(); 2266 } else { 2267 /* remove whole extent: excellent! */ 2268 block = ex_ee_block; 2269 num = 0; 2270 BUG_ON(a != ex_ee_block); 2271 BUG_ON(b != ex_ee_block + ex_ee_len - 1); 2272 } 2273 2274 /* 2275 * 3 for leaf, sb, and inode plus 2 (bmap and group 2276 * descriptor) for each block group; assume two block 2277 * groups plus ex_ee_len/blocks_per_block_group for 2278 * the worst case 2279 */ 2280 credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb)); 2281 if (ex == EXT_FIRST_EXTENT(eh)) { 2282 correct_index = 1; 2283 credits += (ext_depth(inode)) + 1; 2284 } 2285 credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb); 2286 2287 err = ext4_ext_truncate_extend_restart(handle, inode, credits); 2288 if (err) 2289 goto out; 2290 2291 err = ext4_ext_get_access(handle, inode, path + depth); 2292 if (err) 2293 goto out; 2294 2295 err = ext4_remove_blocks(handle, inode, ex, a, b); 2296 if (err) 2297 goto out; 2298 2299 if (num == 0) { 2300 /* this extent is removed; mark slot entirely unused */ 2301 ext4_ext_store_pblock(ex, 0); 2302 le16_add_cpu(&eh->eh_entries, -1); 2303 } 2304 2305 ex->ee_block = cpu_to_le32(block); 2306 ex->ee_len = cpu_to_le16(num); 2307 /* 2308 * Do not mark uninitialized if all the blocks in the 2309 * extent have been removed. 2310 */ 2311 if (uninitialized && num) 2312 ext4_ext_mark_uninitialized(ex); 2313 2314 err = ext4_ext_dirty(handle, inode, path + depth); 2315 if (err) 2316 goto out; 2317 2318 ext_debug("new extent: %u:%u:%llu\n", block, num, 2319 ext_pblock(ex)); 2320 ex--; 2321 ex_ee_block = le32_to_cpu(ex->ee_block); 2322 ex_ee_len = ext4_ext_get_actual_len(ex); 2323 } 2324 2325 if (correct_index && eh->eh_entries) 2326 err = ext4_ext_correct_indexes(handle, inode, path); 2327 2328 /* if this leaf is free, then we should 2329 * remove it from index block above */ 2330 if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL) 2331 err = ext4_ext_rm_idx(handle, inode, path + depth); 2332 2333 out: 2334 return err; 2335 } 2336 2337 /* 2338 * ext4_ext_more_to_rm: 2339 * returns 1 if current index has to be freed (even partial) 2340 */ 2341 static int 2342 ext4_ext_more_to_rm(struct ext4_ext_path *path) 2343 { 2344 BUG_ON(path->p_idx == NULL); 2345 2346 if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr)) 2347 return 0; 2348 2349 /* 2350 * if truncate on deeper level happened, it wasn't partial, 2351 * so we have to consider current index for truncation 2352 */ 2353 if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block) 2354 return 0; 2355 return 1; 2356 } 2357 2358 static int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start) 2359 { 2360 struct super_block *sb = inode->i_sb; 2361 int depth = ext_depth(inode); 2362 struct ext4_ext_path *path; 2363 handle_t *handle; 2364 int i = 0, err = 0; 2365 2366 ext_debug("truncate since %u\n", start); 2367 2368 /* probably first extent we're gonna free will be last in block */ 2369 handle = ext4_journal_start(inode, depth + 1); 2370 if (IS_ERR(handle)) 2371 return PTR_ERR(handle); 2372 2373 ext4_ext_invalidate_cache(inode); 2374 2375 /* 2376 * We start scanning from right side, freeing all the blocks 2377 * after i_size and walking into the tree depth-wise. 2378 */ 2379 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1), GFP_NOFS); 2380 if (path == NULL) { 2381 ext4_journal_stop(handle); 2382 return -ENOMEM; 2383 } 2384 path[0].p_hdr = ext_inode_hdr(inode); 2385 if (ext4_ext_check(inode, path[0].p_hdr, depth)) { 2386 err = -EIO; 2387 goto out; 2388 } 2389 path[0].p_depth = depth; 2390 2391 while (i >= 0 && err == 0) { 2392 if (i == depth) { 2393 /* this is leaf block */ 2394 err = ext4_ext_rm_leaf(handle, inode, path, start); 2395 /* root level has p_bh == NULL, brelse() eats this */ 2396 brelse(path[i].p_bh); 2397 path[i].p_bh = NULL; 2398 i--; 2399 continue; 2400 } 2401 2402 /* this is index block */ 2403 if (!path[i].p_hdr) { 2404 ext_debug("initialize header\n"); 2405 path[i].p_hdr = ext_block_hdr(path[i].p_bh); 2406 } 2407 2408 if (!path[i].p_idx) { 2409 /* this level hasn't been touched yet */ 2410 path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr); 2411 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1; 2412 ext_debug("init index ptr: hdr 0x%p, num %d\n", 2413 path[i].p_hdr, 2414 le16_to_cpu(path[i].p_hdr->eh_entries)); 2415 } else { 2416 /* we were already here, see at next index */ 2417 path[i].p_idx--; 2418 } 2419 2420 ext_debug("level %d - index, first 0x%p, cur 0x%p\n", 2421 i, EXT_FIRST_INDEX(path[i].p_hdr), 2422 path[i].p_idx); 2423 if (ext4_ext_more_to_rm(path + i)) { 2424 struct buffer_head *bh; 2425 /* go to the next level */ 2426 ext_debug("move to level %d (block %llu)\n", 2427 i + 1, idx_pblock(path[i].p_idx)); 2428 memset(path + i + 1, 0, sizeof(*path)); 2429 bh = sb_bread(sb, idx_pblock(path[i].p_idx)); 2430 if (!bh) { 2431 /* should we reset i_size? */ 2432 err = -EIO; 2433 break; 2434 } 2435 if (WARN_ON(i + 1 > depth)) { 2436 err = -EIO; 2437 break; 2438 } 2439 if (ext4_ext_check(inode, ext_block_hdr(bh), 2440 depth - i - 1)) { 2441 err = -EIO; 2442 break; 2443 } 2444 path[i + 1].p_bh = bh; 2445 2446 /* save actual number of indexes since this 2447 * number is changed at the next iteration */ 2448 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries); 2449 i++; 2450 } else { 2451 /* we finished processing this index, go up */ 2452 if (path[i].p_hdr->eh_entries == 0 && i > 0) { 2453 /* index is empty, remove it; 2454 * handle must be already prepared by the 2455 * truncatei_leaf() */ 2456 err = ext4_ext_rm_idx(handle, inode, path + i); 2457 } 2458 /* root level has p_bh == NULL, brelse() eats this */ 2459 brelse(path[i].p_bh); 2460 path[i].p_bh = NULL; 2461 i--; 2462 ext_debug("return to level %d\n", i); 2463 } 2464 } 2465 2466 /* TODO: flexible tree reduction should be here */ 2467 if (path->p_hdr->eh_entries == 0) { 2468 /* 2469 * truncate to zero freed all the tree, 2470 * so we need to correct eh_depth 2471 */ 2472 err = ext4_ext_get_access(handle, inode, path); 2473 if (err == 0) { 2474 ext_inode_hdr(inode)->eh_depth = 0; 2475 ext_inode_hdr(inode)->eh_max = 2476 cpu_to_le16(ext4_ext_space_root(inode, 0)); 2477 err = ext4_ext_dirty(handle, inode, path); 2478 } 2479 } 2480 out: 2481 ext4_ext_drop_refs(path); 2482 kfree(path); 2483 ext4_journal_stop(handle); 2484 2485 return err; 2486 } 2487 2488 /* 2489 * called at mount time 2490 */ 2491 void ext4_ext_init(struct super_block *sb) 2492 { 2493 /* 2494 * possible initialization would be here 2495 */ 2496 2497 if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) { 2498 #if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS) 2499 printk(KERN_INFO "EXT4-fs: file extents enabled"); 2500 #ifdef AGGRESSIVE_TEST 2501 printk(", aggressive tests"); 2502 #endif 2503 #ifdef CHECK_BINSEARCH 2504 printk(", check binsearch"); 2505 #endif 2506 #ifdef EXTENTS_STATS 2507 printk(", stats"); 2508 #endif 2509 printk("\n"); 2510 #endif 2511 #ifdef EXTENTS_STATS 2512 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock); 2513 EXT4_SB(sb)->s_ext_min = 1 << 30; 2514 EXT4_SB(sb)->s_ext_max = 0; 2515 #endif 2516 } 2517 } 2518 2519 /* 2520 * called at umount time 2521 */ 2522 void ext4_ext_release(struct super_block *sb) 2523 { 2524 if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) 2525 return; 2526 2527 #ifdef EXTENTS_STATS 2528 if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) { 2529 struct ext4_sb_info *sbi = EXT4_SB(sb); 2530 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n", 2531 sbi->s_ext_blocks, sbi->s_ext_extents, 2532 sbi->s_ext_blocks / sbi->s_ext_extents); 2533 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n", 2534 sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max); 2535 } 2536 #endif 2537 } 2538 2539 static void bi_complete(struct bio *bio, int error) 2540 { 2541 complete((struct completion *)bio->bi_private); 2542 } 2543 2544 /* FIXME!! we need to try to merge to left or right after zero-out */ 2545 static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex) 2546 { 2547 int ret = -EIO; 2548 struct bio *bio; 2549 int blkbits, blocksize; 2550 sector_t ee_pblock; 2551 struct completion event; 2552 unsigned int ee_len, len, done, offset; 2553 2554 2555 blkbits = inode->i_blkbits; 2556 blocksize = inode->i_sb->s_blocksize; 2557 ee_len = ext4_ext_get_actual_len(ex); 2558 ee_pblock = ext_pblock(ex); 2559 2560 /* convert ee_pblock to 512 byte sectors */ 2561 ee_pblock = ee_pblock << (blkbits - 9); 2562 2563 while (ee_len > 0) { 2564 2565 if (ee_len > BIO_MAX_PAGES) 2566 len = BIO_MAX_PAGES; 2567 else 2568 len = ee_len; 2569 2570 bio = bio_alloc(GFP_NOIO, len); 2571 bio->bi_sector = ee_pblock; 2572 bio->bi_bdev = inode->i_sb->s_bdev; 2573 2574 done = 0; 2575 offset = 0; 2576 while (done < len) { 2577 ret = bio_add_page(bio, ZERO_PAGE(0), 2578 blocksize, offset); 2579 if (ret != blocksize) { 2580 /* 2581 * We can't add any more pages because of 2582 * hardware limitations. Start a new bio. 2583 */ 2584 break; 2585 } 2586 done++; 2587 offset += blocksize; 2588 if (offset >= PAGE_CACHE_SIZE) 2589 offset = 0; 2590 } 2591 2592 init_completion(&event); 2593 bio->bi_private = &event; 2594 bio->bi_end_io = bi_complete; 2595 submit_bio(WRITE, bio); 2596 wait_for_completion(&event); 2597 2598 if (test_bit(BIO_UPTODATE, &bio->bi_flags)) 2599 ret = 0; 2600 else { 2601 ret = -EIO; 2602 break; 2603 } 2604 bio_put(bio); 2605 ee_len -= done; 2606 ee_pblock += done << (blkbits - 9); 2607 } 2608 return ret; 2609 } 2610 2611 #define EXT4_EXT_ZERO_LEN 7 2612 /* 2613 * This function is called by ext4_ext_get_blocks() if someone tries to write 2614 * to an uninitialized extent. It may result in splitting the uninitialized 2615 * extent into multiple extents (upto three - one initialized and two 2616 * uninitialized). 2617 * There are three possibilities: 2618 * a> There is no split required: Entire extent should be initialized 2619 * b> Splits in two extents: Write is happening at either end of the extent 2620 * c> Splits in three extents: Somone is writing in middle of the extent 2621 */ 2622 static int ext4_ext_convert_to_initialized(handle_t *handle, 2623 struct inode *inode, 2624 struct ext4_ext_path *path, 2625 ext4_lblk_t iblock, 2626 unsigned int max_blocks) 2627 { 2628 struct ext4_extent *ex, newex, orig_ex; 2629 struct ext4_extent *ex1 = NULL; 2630 struct ext4_extent *ex2 = NULL; 2631 struct ext4_extent *ex3 = NULL; 2632 struct ext4_extent_header *eh; 2633 ext4_lblk_t ee_block; 2634 unsigned int allocated, ee_len, depth; 2635 ext4_fsblk_t newblock; 2636 int err = 0; 2637 int ret = 0; 2638 2639 depth = ext_depth(inode); 2640 eh = path[depth].p_hdr; 2641 ex = path[depth].p_ext; 2642 ee_block = le32_to_cpu(ex->ee_block); 2643 ee_len = ext4_ext_get_actual_len(ex); 2644 allocated = ee_len - (iblock - ee_block); 2645 newblock = iblock - ee_block + ext_pblock(ex); 2646 ex2 = ex; 2647 orig_ex.ee_block = ex->ee_block; 2648 orig_ex.ee_len = cpu_to_le16(ee_len); 2649 ext4_ext_store_pblock(&orig_ex, ext_pblock(ex)); 2650 2651 err = ext4_ext_get_access(handle, inode, path + depth); 2652 if (err) 2653 goto out; 2654 /* If extent has less than 2*EXT4_EXT_ZERO_LEN zerout directly */ 2655 if (ee_len <= 2*EXT4_EXT_ZERO_LEN) { 2656 err = ext4_ext_zeroout(inode, &orig_ex); 2657 if (err) 2658 goto fix_extent_len; 2659 /* update the extent length and mark as initialized */ 2660 ex->ee_block = orig_ex.ee_block; 2661 ex->ee_len = orig_ex.ee_len; 2662 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2663 ext4_ext_dirty(handle, inode, path + depth); 2664 /* zeroed the full extent */ 2665 return allocated; 2666 } 2667 2668 /* ex1: ee_block to iblock - 1 : uninitialized */ 2669 if (iblock > ee_block) { 2670 ex1 = ex; 2671 ex1->ee_len = cpu_to_le16(iblock - ee_block); 2672 ext4_ext_mark_uninitialized(ex1); 2673 ex2 = &newex; 2674 } 2675 /* 2676 * for sanity, update the length of the ex2 extent before 2677 * we insert ex3, if ex1 is NULL. This is to avoid temporary 2678 * overlap of blocks. 2679 */ 2680 if (!ex1 && allocated > max_blocks) 2681 ex2->ee_len = cpu_to_le16(max_blocks); 2682 /* ex3: to ee_block + ee_len : uninitialised */ 2683 if (allocated > max_blocks) { 2684 unsigned int newdepth; 2685 /* If extent has less than EXT4_EXT_ZERO_LEN zerout directly */ 2686 if (allocated <= EXT4_EXT_ZERO_LEN) { 2687 /* 2688 * iblock == ee_block is handled by the zerouout 2689 * at the beginning. 2690 * Mark first half uninitialized. 2691 * Mark second half initialized and zero out the 2692 * initialized extent 2693 */ 2694 ex->ee_block = orig_ex.ee_block; 2695 ex->ee_len = cpu_to_le16(ee_len - allocated); 2696 ext4_ext_mark_uninitialized(ex); 2697 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2698 ext4_ext_dirty(handle, inode, path + depth); 2699 2700 ex3 = &newex; 2701 ex3->ee_block = cpu_to_le32(iblock); 2702 ext4_ext_store_pblock(ex3, newblock); 2703 ex3->ee_len = cpu_to_le16(allocated); 2704 err = ext4_ext_insert_extent(handle, inode, path, 2705 ex3, 0); 2706 if (err == -ENOSPC) { 2707 err = ext4_ext_zeroout(inode, &orig_ex); 2708 if (err) 2709 goto fix_extent_len; 2710 ex->ee_block = orig_ex.ee_block; 2711 ex->ee_len = orig_ex.ee_len; 2712 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2713 ext4_ext_dirty(handle, inode, path + depth); 2714 /* blocks available from iblock */ 2715 return allocated; 2716 2717 } else if (err) 2718 goto fix_extent_len; 2719 2720 /* 2721 * We need to zero out the second half because 2722 * an fallocate request can update file size and 2723 * converting the second half to initialized extent 2724 * implies that we can leak some junk data to user 2725 * space. 2726 */ 2727 err = ext4_ext_zeroout(inode, ex3); 2728 if (err) { 2729 /* 2730 * We should actually mark the 2731 * second half as uninit and return error 2732 * Insert would have changed the extent 2733 */ 2734 depth = ext_depth(inode); 2735 ext4_ext_drop_refs(path); 2736 path = ext4_ext_find_extent(inode, 2737 iblock, path); 2738 if (IS_ERR(path)) { 2739 err = PTR_ERR(path); 2740 return err; 2741 } 2742 /* get the second half extent details */ 2743 ex = path[depth].p_ext; 2744 err = ext4_ext_get_access(handle, inode, 2745 path + depth); 2746 if (err) 2747 return err; 2748 ext4_ext_mark_uninitialized(ex); 2749 ext4_ext_dirty(handle, inode, path + depth); 2750 return err; 2751 } 2752 2753 /* zeroed the second half */ 2754 return allocated; 2755 } 2756 ex3 = &newex; 2757 ex3->ee_block = cpu_to_le32(iblock + max_blocks); 2758 ext4_ext_store_pblock(ex3, newblock + max_blocks); 2759 ex3->ee_len = cpu_to_le16(allocated - max_blocks); 2760 ext4_ext_mark_uninitialized(ex3); 2761 err = ext4_ext_insert_extent(handle, inode, path, ex3, 0); 2762 if (err == -ENOSPC) { 2763 err = ext4_ext_zeroout(inode, &orig_ex); 2764 if (err) 2765 goto fix_extent_len; 2766 /* update the extent length and mark as initialized */ 2767 ex->ee_block = orig_ex.ee_block; 2768 ex->ee_len = orig_ex.ee_len; 2769 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2770 ext4_ext_dirty(handle, inode, path + depth); 2771 /* zeroed the full extent */ 2772 /* blocks available from iblock */ 2773 return allocated; 2774 2775 } else if (err) 2776 goto fix_extent_len; 2777 /* 2778 * The depth, and hence eh & ex might change 2779 * as part of the insert above. 2780 */ 2781 newdepth = ext_depth(inode); 2782 /* 2783 * update the extent length after successful insert of the 2784 * split extent 2785 */ 2786 orig_ex.ee_len = cpu_to_le16(ee_len - 2787 ext4_ext_get_actual_len(ex3)); 2788 depth = newdepth; 2789 ext4_ext_drop_refs(path); 2790 path = ext4_ext_find_extent(inode, iblock, path); 2791 if (IS_ERR(path)) { 2792 err = PTR_ERR(path); 2793 goto out; 2794 } 2795 eh = path[depth].p_hdr; 2796 ex = path[depth].p_ext; 2797 if (ex2 != &newex) 2798 ex2 = ex; 2799 2800 err = ext4_ext_get_access(handle, inode, path + depth); 2801 if (err) 2802 goto out; 2803 2804 allocated = max_blocks; 2805 2806 /* If extent has less than EXT4_EXT_ZERO_LEN and we are trying 2807 * to insert a extent in the middle zerout directly 2808 * otherwise give the extent a chance to merge to left 2809 */ 2810 if (le16_to_cpu(orig_ex.ee_len) <= EXT4_EXT_ZERO_LEN && 2811 iblock != ee_block) { 2812 err = ext4_ext_zeroout(inode, &orig_ex); 2813 if (err) 2814 goto fix_extent_len; 2815 /* update the extent length and mark as initialized */ 2816 ex->ee_block = orig_ex.ee_block; 2817 ex->ee_len = orig_ex.ee_len; 2818 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2819 ext4_ext_dirty(handle, inode, path + depth); 2820 /* zero out the first half */ 2821 /* blocks available from iblock */ 2822 return allocated; 2823 } 2824 } 2825 /* 2826 * If there was a change of depth as part of the 2827 * insertion of ex3 above, we need to update the length 2828 * of the ex1 extent again here 2829 */ 2830 if (ex1 && ex1 != ex) { 2831 ex1 = ex; 2832 ex1->ee_len = cpu_to_le16(iblock - ee_block); 2833 ext4_ext_mark_uninitialized(ex1); 2834 ex2 = &newex; 2835 } 2836 /* ex2: iblock to iblock + maxblocks-1 : initialised */ 2837 ex2->ee_block = cpu_to_le32(iblock); 2838 ext4_ext_store_pblock(ex2, newblock); 2839 ex2->ee_len = cpu_to_le16(allocated); 2840 if (ex2 != ex) 2841 goto insert; 2842 /* 2843 * New (initialized) extent starts from the first block 2844 * in the current extent. i.e., ex2 == ex 2845 * We have to see if it can be merged with the extent 2846 * on the left. 2847 */ 2848 if (ex2 > EXT_FIRST_EXTENT(eh)) { 2849 /* 2850 * To merge left, pass "ex2 - 1" to try_to_merge(), 2851 * since it merges towards right _only_. 2852 */ 2853 ret = ext4_ext_try_to_merge(inode, path, ex2 - 1); 2854 if (ret) { 2855 err = ext4_ext_correct_indexes(handle, inode, path); 2856 if (err) 2857 goto out; 2858 depth = ext_depth(inode); 2859 ex2--; 2860 } 2861 } 2862 /* 2863 * Try to Merge towards right. This might be required 2864 * only when the whole extent is being written to. 2865 * i.e. ex2 == ex and ex3 == NULL. 2866 */ 2867 if (!ex3) { 2868 ret = ext4_ext_try_to_merge(inode, path, ex2); 2869 if (ret) { 2870 err = ext4_ext_correct_indexes(handle, inode, path); 2871 if (err) 2872 goto out; 2873 } 2874 } 2875 /* Mark modified extent as dirty */ 2876 err = ext4_ext_dirty(handle, inode, path + depth); 2877 goto out; 2878 insert: 2879 err = ext4_ext_insert_extent(handle, inode, path, &newex, 0); 2880 if (err == -ENOSPC) { 2881 err = ext4_ext_zeroout(inode, &orig_ex); 2882 if (err) 2883 goto fix_extent_len; 2884 /* update the extent length and mark as initialized */ 2885 ex->ee_block = orig_ex.ee_block; 2886 ex->ee_len = orig_ex.ee_len; 2887 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2888 ext4_ext_dirty(handle, inode, path + depth); 2889 /* zero out the first half */ 2890 return allocated; 2891 } else if (err) 2892 goto fix_extent_len; 2893 out: 2894 ext4_ext_show_leaf(inode, path); 2895 return err ? err : allocated; 2896 2897 fix_extent_len: 2898 ex->ee_block = orig_ex.ee_block; 2899 ex->ee_len = orig_ex.ee_len; 2900 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2901 ext4_ext_mark_uninitialized(ex); 2902 ext4_ext_dirty(handle, inode, path + depth); 2903 return err; 2904 } 2905 2906 /* 2907 * This function is called by ext4_ext_get_blocks() from 2908 * ext4_get_blocks_dio_write() when DIO to write 2909 * to an uninitialized extent. 2910 * 2911 * Writing to an uninitized extent may result in splitting the uninitialized 2912 * extent into multiple /intialized unintialized extents (up to three) 2913 * There are three possibilities: 2914 * a> There is no split required: Entire extent should be uninitialized 2915 * b> Splits in two extents: Write is happening at either end of the extent 2916 * c> Splits in three extents: Somone is writing in middle of the extent 2917 * 2918 * One of more index blocks maybe needed if the extent tree grow after 2919 * the unintialized extent split. To prevent ENOSPC occur at the IO 2920 * complete, we need to split the uninitialized extent before DIO submit 2921 * the IO. The uninitilized extent called at this time will be split 2922 * into three uninitialized extent(at most). After IO complete, the part 2923 * being filled will be convert to initialized by the end_io callback function 2924 * via ext4_convert_unwritten_extents(). 2925 * 2926 * Returns the size of uninitialized extent to be written on success. 2927 */ 2928 static int ext4_split_unwritten_extents(handle_t *handle, 2929 struct inode *inode, 2930 struct ext4_ext_path *path, 2931 ext4_lblk_t iblock, 2932 unsigned int max_blocks, 2933 int flags) 2934 { 2935 struct ext4_extent *ex, newex, orig_ex; 2936 struct ext4_extent *ex1 = NULL; 2937 struct ext4_extent *ex2 = NULL; 2938 struct ext4_extent *ex3 = NULL; 2939 struct ext4_extent_header *eh; 2940 ext4_lblk_t ee_block; 2941 unsigned int allocated, ee_len, depth; 2942 ext4_fsblk_t newblock; 2943 int err = 0; 2944 2945 ext_debug("ext4_split_unwritten_extents: inode %lu," 2946 "iblock %llu, max_blocks %u\n", inode->i_ino, 2947 (unsigned long long)iblock, max_blocks); 2948 depth = ext_depth(inode); 2949 eh = path[depth].p_hdr; 2950 ex = path[depth].p_ext; 2951 ee_block = le32_to_cpu(ex->ee_block); 2952 ee_len = ext4_ext_get_actual_len(ex); 2953 allocated = ee_len - (iblock - ee_block); 2954 newblock = iblock - ee_block + ext_pblock(ex); 2955 ex2 = ex; 2956 orig_ex.ee_block = ex->ee_block; 2957 orig_ex.ee_len = cpu_to_le16(ee_len); 2958 ext4_ext_store_pblock(&orig_ex, ext_pblock(ex)); 2959 2960 /* 2961 * If the uninitialized extent begins at the same logical 2962 * block where the write begins, and the write completely 2963 * covers the extent, then we don't need to split it. 2964 */ 2965 if ((iblock == ee_block) && (allocated <= max_blocks)) 2966 return allocated; 2967 2968 err = ext4_ext_get_access(handle, inode, path + depth); 2969 if (err) 2970 goto out; 2971 /* ex1: ee_block to iblock - 1 : uninitialized */ 2972 if (iblock > ee_block) { 2973 ex1 = ex; 2974 ex1->ee_len = cpu_to_le16(iblock - ee_block); 2975 ext4_ext_mark_uninitialized(ex1); 2976 ex2 = &newex; 2977 } 2978 /* 2979 * for sanity, update the length of the ex2 extent before 2980 * we insert ex3, if ex1 is NULL. This is to avoid temporary 2981 * overlap of blocks. 2982 */ 2983 if (!ex1 && allocated > max_blocks) 2984 ex2->ee_len = cpu_to_le16(max_blocks); 2985 /* ex3: to ee_block + ee_len : uninitialised */ 2986 if (allocated > max_blocks) { 2987 unsigned int newdepth; 2988 ex3 = &newex; 2989 ex3->ee_block = cpu_to_le32(iblock + max_blocks); 2990 ext4_ext_store_pblock(ex3, newblock + max_blocks); 2991 ex3->ee_len = cpu_to_le16(allocated - max_blocks); 2992 ext4_ext_mark_uninitialized(ex3); 2993 err = ext4_ext_insert_extent(handle, inode, path, ex3, flags); 2994 if (err == -ENOSPC) { 2995 err = ext4_ext_zeroout(inode, &orig_ex); 2996 if (err) 2997 goto fix_extent_len; 2998 /* update the extent length and mark as initialized */ 2999 ex->ee_block = orig_ex.ee_block; 3000 ex->ee_len = orig_ex.ee_len; 3001 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 3002 ext4_ext_dirty(handle, inode, path + depth); 3003 /* zeroed the full extent */ 3004 /* blocks available from iblock */ 3005 return allocated; 3006 3007 } else if (err) 3008 goto fix_extent_len; 3009 /* 3010 * The depth, and hence eh & ex might change 3011 * as part of the insert above. 3012 */ 3013 newdepth = ext_depth(inode); 3014 /* 3015 * update the extent length after successful insert of the 3016 * split extent 3017 */ 3018 orig_ex.ee_len = cpu_to_le16(ee_len - 3019 ext4_ext_get_actual_len(ex3)); 3020 depth = newdepth; 3021 ext4_ext_drop_refs(path); 3022 path = ext4_ext_find_extent(inode, iblock, path); 3023 if (IS_ERR(path)) { 3024 err = PTR_ERR(path); 3025 goto out; 3026 } 3027 eh = path[depth].p_hdr; 3028 ex = path[depth].p_ext; 3029 if (ex2 != &newex) 3030 ex2 = ex; 3031 3032 err = ext4_ext_get_access(handle, inode, path + depth); 3033 if (err) 3034 goto out; 3035 3036 allocated = max_blocks; 3037 } 3038 /* 3039 * If there was a change of depth as part of the 3040 * insertion of ex3 above, we need to update the length 3041 * of the ex1 extent again here 3042 */ 3043 if (ex1 && ex1 != ex) { 3044 ex1 = ex; 3045 ex1->ee_len = cpu_to_le16(iblock - ee_block); 3046 ext4_ext_mark_uninitialized(ex1); 3047 ex2 = &newex; 3048 } 3049 /* 3050 * ex2: iblock to iblock + maxblocks-1 : to be direct IO written, 3051 * uninitialised still. 3052 */ 3053 ex2->ee_block = cpu_to_le32(iblock); 3054 ext4_ext_store_pblock(ex2, newblock); 3055 ex2->ee_len = cpu_to_le16(allocated); 3056 ext4_ext_mark_uninitialized(ex2); 3057 if (ex2 != ex) 3058 goto insert; 3059 /* Mark modified extent as dirty */ 3060 err = ext4_ext_dirty(handle, inode, path + depth); 3061 ext_debug("out here\n"); 3062 goto out; 3063 insert: 3064 err = ext4_ext_insert_extent(handle, inode, path, &newex, flags); 3065 if (err == -ENOSPC) { 3066 err = ext4_ext_zeroout(inode, &orig_ex); 3067 if (err) 3068 goto fix_extent_len; 3069 /* update the extent length and mark as initialized */ 3070 ex->ee_block = orig_ex.ee_block; 3071 ex->ee_len = orig_ex.ee_len; 3072 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 3073 ext4_ext_dirty(handle, inode, path + depth); 3074 /* zero out the first half */ 3075 return allocated; 3076 } else if (err) 3077 goto fix_extent_len; 3078 out: 3079 ext4_ext_show_leaf(inode, path); 3080 return err ? err : allocated; 3081 3082 fix_extent_len: 3083 ex->ee_block = orig_ex.ee_block; 3084 ex->ee_len = orig_ex.ee_len; 3085 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 3086 ext4_ext_mark_uninitialized(ex); 3087 ext4_ext_dirty(handle, inode, path + depth); 3088 return err; 3089 } 3090 static int ext4_convert_unwritten_extents_endio(handle_t *handle, 3091 struct inode *inode, 3092 struct ext4_ext_path *path) 3093 { 3094 struct ext4_extent *ex; 3095 struct ext4_extent_header *eh; 3096 int depth; 3097 int err = 0; 3098 int ret = 0; 3099 3100 depth = ext_depth(inode); 3101 eh = path[depth].p_hdr; 3102 ex = path[depth].p_ext; 3103 3104 err = ext4_ext_get_access(handle, inode, path + depth); 3105 if (err) 3106 goto out; 3107 /* first mark the extent as initialized */ 3108 ext4_ext_mark_initialized(ex); 3109 3110 /* 3111 * We have to see if it can be merged with the extent 3112 * on the left. 3113 */ 3114 if (ex > EXT_FIRST_EXTENT(eh)) { 3115 /* 3116 * To merge left, pass "ex - 1" to try_to_merge(), 3117 * since it merges towards right _only_. 3118 */ 3119 ret = ext4_ext_try_to_merge(inode, path, ex - 1); 3120 if (ret) { 3121 err = ext4_ext_correct_indexes(handle, inode, path); 3122 if (err) 3123 goto out; 3124 depth = ext_depth(inode); 3125 ex--; 3126 } 3127 } 3128 /* 3129 * Try to Merge towards right. 3130 */ 3131 ret = ext4_ext_try_to_merge(inode, path, ex); 3132 if (ret) { 3133 err = ext4_ext_correct_indexes(handle, inode, path); 3134 if (err) 3135 goto out; 3136 depth = ext_depth(inode); 3137 } 3138 /* Mark modified extent as dirty */ 3139 err = ext4_ext_dirty(handle, inode, path + depth); 3140 out: 3141 ext4_ext_show_leaf(inode, path); 3142 return err; 3143 } 3144 3145 static void unmap_underlying_metadata_blocks(struct block_device *bdev, 3146 sector_t block, int count) 3147 { 3148 int i; 3149 for (i = 0; i < count; i++) 3150 unmap_underlying_metadata(bdev, block + i); 3151 } 3152 3153 static int 3154 ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode, 3155 ext4_lblk_t iblock, unsigned int max_blocks, 3156 struct ext4_ext_path *path, int flags, 3157 unsigned int allocated, struct buffer_head *bh_result, 3158 ext4_fsblk_t newblock) 3159 { 3160 int ret = 0; 3161 int err = 0; 3162 ext4_io_end_t *io = EXT4_I(inode)->cur_aio_dio; 3163 3164 ext_debug("ext4_ext_handle_uninitialized_extents: inode %lu, logical" 3165 "block %llu, max_blocks %u, flags %d, allocated %u", 3166 inode->i_ino, (unsigned long long)iblock, max_blocks, 3167 flags, allocated); 3168 ext4_ext_show_leaf(inode, path); 3169 3170 /* get_block() before submit the IO, split the extent */ 3171 if ((flags & EXT4_GET_BLOCKS_PRE_IO)) { 3172 ret = ext4_split_unwritten_extents(handle, 3173 inode, path, iblock, 3174 max_blocks, flags); 3175 /* 3176 * Flag the inode(non aio case) or end_io struct (aio case) 3177 * that this IO needs to convertion to written when IO is 3178 * completed 3179 */ 3180 if (io) 3181 io->flag = EXT4_IO_UNWRITTEN; 3182 else 3183 ext4_set_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN); 3184 if (ext4_should_dioread_nolock(inode)) 3185 set_buffer_uninit(bh_result); 3186 goto out; 3187 } 3188 /* IO end_io complete, convert the filled extent to written */ 3189 if ((flags & EXT4_GET_BLOCKS_CONVERT)) { 3190 ret = ext4_convert_unwritten_extents_endio(handle, inode, 3191 path); 3192 if (ret >= 0) 3193 ext4_update_inode_fsync_trans(handle, inode, 1); 3194 goto out2; 3195 } 3196 /* buffered IO case */ 3197 /* 3198 * repeat fallocate creation request 3199 * we already have an unwritten extent 3200 */ 3201 if (flags & EXT4_GET_BLOCKS_UNINIT_EXT) 3202 goto map_out; 3203 3204 /* buffered READ or buffered write_begin() lookup */ 3205 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) { 3206 /* 3207 * We have blocks reserved already. We 3208 * return allocated blocks so that delalloc 3209 * won't do block reservation for us. But 3210 * the buffer head will be unmapped so that 3211 * a read from the block returns 0s. 3212 */ 3213 set_buffer_unwritten(bh_result); 3214 goto out1; 3215 } 3216 3217 /* buffered write, writepage time, convert*/ 3218 ret = ext4_ext_convert_to_initialized(handle, inode, 3219 path, iblock, 3220 max_blocks); 3221 if (ret >= 0) 3222 ext4_update_inode_fsync_trans(handle, inode, 1); 3223 out: 3224 if (ret <= 0) { 3225 err = ret; 3226 goto out2; 3227 } else 3228 allocated = ret; 3229 set_buffer_new(bh_result); 3230 /* 3231 * if we allocated more blocks than requested 3232 * we need to make sure we unmap the extra block 3233 * allocated. The actual needed block will get 3234 * unmapped later when we find the buffer_head marked 3235 * new. 3236 */ 3237 if (allocated > max_blocks) { 3238 unmap_underlying_metadata_blocks(inode->i_sb->s_bdev, 3239 newblock + max_blocks, 3240 allocated - max_blocks); 3241 allocated = max_blocks; 3242 } 3243 3244 /* 3245 * If we have done fallocate with the offset that is already 3246 * delayed allocated, we would have block reservation 3247 * and quota reservation done in the delayed write path. 3248 * But fallocate would have already updated quota and block 3249 * count for this offset. So cancel these reservation 3250 */ 3251 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) 3252 ext4_da_update_reserve_space(inode, allocated, 0); 3253 3254 map_out: 3255 set_buffer_mapped(bh_result); 3256 out1: 3257 if (allocated > max_blocks) 3258 allocated = max_blocks; 3259 ext4_ext_show_leaf(inode, path); 3260 bh_result->b_bdev = inode->i_sb->s_bdev; 3261 bh_result->b_blocknr = newblock; 3262 out2: 3263 if (path) { 3264 ext4_ext_drop_refs(path); 3265 kfree(path); 3266 } 3267 return err ? err : allocated; 3268 } 3269 /* 3270 * Block allocation/map/preallocation routine for extents based files 3271 * 3272 * 3273 * Need to be called with 3274 * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block 3275 * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem) 3276 * 3277 * return > 0, number of of blocks already mapped/allocated 3278 * if create == 0 and these are pre-allocated blocks 3279 * buffer head is unmapped 3280 * otherwise blocks are mapped 3281 * 3282 * return = 0, if plain look up failed (blocks have not been allocated) 3283 * buffer head is unmapped 3284 * 3285 * return < 0, error case. 3286 */ 3287 int ext4_ext_get_blocks(handle_t *handle, struct inode *inode, 3288 ext4_lblk_t iblock, 3289 unsigned int max_blocks, struct buffer_head *bh_result, 3290 int flags) 3291 { 3292 struct ext4_ext_path *path = NULL; 3293 struct ext4_extent_header *eh; 3294 struct ext4_extent newex, *ex, *last_ex; 3295 ext4_fsblk_t newblock; 3296 int err = 0, depth, ret, cache_type; 3297 unsigned int allocated = 0; 3298 struct ext4_allocation_request ar; 3299 ext4_io_end_t *io = EXT4_I(inode)->cur_aio_dio; 3300 3301 __clear_bit(BH_New, &bh_result->b_state); 3302 ext_debug("blocks %u/%u requested for inode %lu\n", 3303 iblock, max_blocks, inode->i_ino); 3304 3305 /* check in cache */ 3306 cache_type = ext4_ext_in_cache(inode, iblock, &newex); 3307 if (cache_type) { 3308 if (cache_type == EXT4_EXT_CACHE_GAP) { 3309 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) { 3310 /* 3311 * block isn't allocated yet and 3312 * user doesn't want to allocate it 3313 */ 3314 goto out2; 3315 } 3316 /* we should allocate requested block */ 3317 } else if (cache_type == EXT4_EXT_CACHE_EXTENT) { 3318 /* block is already allocated */ 3319 newblock = iblock 3320 - le32_to_cpu(newex.ee_block) 3321 + ext_pblock(&newex); 3322 /* number of remaining blocks in the extent */ 3323 allocated = ext4_ext_get_actual_len(&newex) - 3324 (iblock - le32_to_cpu(newex.ee_block)); 3325 goto out; 3326 } else { 3327 BUG(); 3328 } 3329 } 3330 3331 /* find extent for this block */ 3332 path = ext4_ext_find_extent(inode, iblock, NULL); 3333 if (IS_ERR(path)) { 3334 err = PTR_ERR(path); 3335 path = NULL; 3336 goto out2; 3337 } 3338 3339 depth = ext_depth(inode); 3340 3341 /* 3342 * consistent leaf must not be empty; 3343 * this situation is possible, though, _during_ tree modification; 3344 * this is why assert can't be put in ext4_ext_find_extent() 3345 */ 3346 if (unlikely(path[depth].p_ext == NULL && depth != 0)) { 3347 EXT4_ERROR_INODE(inode, "bad extent address " 3348 "iblock: %d, depth: %d pblock %lld", 3349 iblock, depth, path[depth].p_block); 3350 err = -EIO; 3351 goto out2; 3352 } 3353 eh = path[depth].p_hdr; 3354 3355 ex = path[depth].p_ext; 3356 if (ex) { 3357 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block); 3358 ext4_fsblk_t ee_start = ext_pblock(ex); 3359 unsigned short ee_len; 3360 3361 /* 3362 * Uninitialized extents are treated as holes, except that 3363 * we split out initialized portions during a write. 3364 */ 3365 ee_len = ext4_ext_get_actual_len(ex); 3366 /* if found extent covers block, simply return it */ 3367 if (in_range(iblock, ee_block, ee_len)) { 3368 newblock = iblock - ee_block + ee_start; 3369 /* number of remaining blocks in the extent */ 3370 allocated = ee_len - (iblock - ee_block); 3371 ext_debug("%u fit into %u:%d -> %llu\n", iblock, 3372 ee_block, ee_len, newblock); 3373 3374 /* Do not put uninitialized extent in the cache */ 3375 if (!ext4_ext_is_uninitialized(ex)) { 3376 ext4_ext_put_in_cache(inode, ee_block, 3377 ee_len, ee_start, 3378 EXT4_EXT_CACHE_EXTENT); 3379 goto out; 3380 } 3381 ret = ext4_ext_handle_uninitialized_extents(handle, 3382 inode, iblock, max_blocks, path, 3383 flags, allocated, bh_result, newblock); 3384 return ret; 3385 } 3386 } 3387 3388 /* 3389 * requested block isn't allocated yet; 3390 * we couldn't try to create block if create flag is zero 3391 */ 3392 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) { 3393 /* 3394 * put just found gap into cache to speed up 3395 * subsequent requests 3396 */ 3397 ext4_ext_put_gap_in_cache(inode, path, iblock); 3398 goto out2; 3399 } 3400 /* 3401 * Okay, we need to do block allocation. 3402 */ 3403 3404 /* find neighbour allocated blocks */ 3405 ar.lleft = iblock; 3406 err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft); 3407 if (err) 3408 goto out2; 3409 ar.lright = iblock; 3410 err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright); 3411 if (err) 3412 goto out2; 3413 3414 /* 3415 * See if request is beyond maximum number of blocks we can have in 3416 * a single extent. For an initialized extent this limit is 3417 * EXT_INIT_MAX_LEN and for an uninitialized extent this limit is 3418 * EXT_UNINIT_MAX_LEN. 3419 */ 3420 if (max_blocks > EXT_INIT_MAX_LEN && 3421 !(flags & EXT4_GET_BLOCKS_UNINIT_EXT)) 3422 max_blocks = EXT_INIT_MAX_LEN; 3423 else if (max_blocks > EXT_UNINIT_MAX_LEN && 3424 (flags & EXT4_GET_BLOCKS_UNINIT_EXT)) 3425 max_blocks = EXT_UNINIT_MAX_LEN; 3426 3427 /* Check if we can really insert (iblock)::(iblock+max_blocks) extent */ 3428 newex.ee_block = cpu_to_le32(iblock); 3429 newex.ee_len = cpu_to_le16(max_blocks); 3430 err = ext4_ext_check_overlap(inode, &newex, path); 3431 if (err) 3432 allocated = ext4_ext_get_actual_len(&newex); 3433 else 3434 allocated = max_blocks; 3435 3436 /* allocate new block */ 3437 ar.inode = inode; 3438 ar.goal = ext4_ext_find_goal(inode, path, iblock); 3439 ar.logical = iblock; 3440 ar.len = allocated; 3441 if (S_ISREG(inode->i_mode)) 3442 ar.flags = EXT4_MB_HINT_DATA; 3443 else 3444 /* disable in-core preallocation for non-regular files */ 3445 ar.flags = 0; 3446 newblock = ext4_mb_new_blocks(handle, &ar, &err); 3447 if (!newblock) 3448 goto out2; 3449 ext_debug("allocate new block: goal %llu, found %llu/%u\n", 3450 ar.goal, newblock, allocated); 3451 3452 /* try to insert new extent into found leaf and return */ 3453 ext4_ext_store_pblock(&newex, newblock); 3454 newex.ee_len = cpu_to_le16(ar.len); 3455 /* Mark uninitialized */ 3456 if (flags & EXT4_GET_BLOCKS_UNINIT_EXT){ 3457 ext4_ext_mark_uninitialized(&newex); 3458 /* 3459 * io_end structure was created for every IO write to an 3460 * uninitialized extent. To avoid unecessary conversion, 3461 * here we flag the IO that really needs the conversion. 3462 * For non asycn direct IO case, flag the inode state 3463 * that we need to perform convertion when IO is done. 3464 */ 3465 if ((flags & EXT4_GET_BLOCKS_PRE_IO)) { 3466 if (io) 3467 io->flag = EXT4_IO_UNWRITTEN; 3468 else 3469 ext4_set_inode_state(inode, 3470 EXT4_STATE_DIO_UNWRITTEN); 3471 } 3472 if (ext4_should_dioread_nolock(inode)) 3473 set_buffer_uninit(bh_result); 3474 } 3475 3476 if (unlikely(EXT4_I(inode)->i_flags & EXT4_EOFBLOCKS_FL)) { 3477 if (unlikely(!eh->eh_entries)) { 3478 EXT4_ERROR_INODE(inode, 3479 "eh->eh_entries == 0 ee_block %d", 3480 ex->ee_block); 3481 err = -EIO; 3482 goto out2; 3483 } 3484 last_ex = EXT_LAST_EXTENT(eh); 3485 if (iblock + ar.len > le32_to_cpu(last_ex->ee_block) 3486 + ext4_ext_get_actual_len(last_ex)) 3487 EXT4_I(inode)->i_flags &= ~EXT4_EOFBLOCKS_FL; 3488 } 3489 err = ext4_ext_insert_extent(handle, inode, path, &newex, flags); 3490 if (err) { 3491 /* free data blocks we just allocated */ 3492 /* not a good idea to call discard here directly, 3493 * but otherwise we'd need to call it every free() */ 3494 ext4_discard_preallocations(inode); 3495 ext4_free_blocks(handle, inode, 0, ext_pblock(&newex), 3496 ext4_ext_get_actual_len(&newex), 0); 3497 goto out2; 3498 } 3499 3500 /* previous routine could use block we allocated */ 3501 newblock = ext_pblock(&newex); 3502 allocated = ext4_ext_get_actual_len(&newex); 3503 if (allocated > max_blocks) 3504 allocated = max_blocks; 3505 set_buffer_new(bh_result); 3506 3507 /* 3508 * Update reserved blocks/metadata blocks after successful 3509 * block allocation which had been deferred till now. 3510 */ 3511 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) 3512 ext4_da_update_reserve_space(inode, allocated, 1); 3513 3514 /* 3515 * Cache the extent and update transaction to commit on fdatasync only 3516 * when it is _not_ an uninitialized extent. 3517 */ 3518 if ((flags & EXT4_GET_BLOCKS_UNINIT_EXT) == 0) { 3519 ext4_ext_put_in_cache(inode, iblock, allocated, newblock, 3520 EXT4_EXT_CACHE_EXTENT); 3521 ext4_update_inode_fsync_trans(handle, inode, 1); 3522 } else 3523 ext4_update_inode_fsync_trans(handle, inode, 0); 3524 out: 3525 if (allocated > max_blocks) 3526 allocated = max_blocks; 3527 ext4_ext_show_leaf(inode, path); 3528 set_buffer_mapped(bh_result); 3529 bh_result->b_bdev = inode->i_sb->s_bdev; 3530 bh_result->b_blocknr = newblock; 3531 out2: 3532 if (path) { 3533 ext4_ext_drop_refs(path); 3534 kfree(path); 3535 } 3536 return err ? err : allocated; 3537 } 3538 3539 void ext4_ext_truncate(struct inode *inode) 3540 { 3541 struct address_space *mapping = inode->i_mapping; 3542 struct super_block *sb = inode->i_sb; 3543 ext4_lblk_t last_block; 3544 handle_t *handle; 3545 int err = 0; 3546 3547 /* 3548 * probably first extent we're gonna free will be last in block 3549 */ 3550 err = ext4_writepage_trans_blocks(inode); 3551 handle = ext4_journal_start(inode, err); 3552 if (IS_ERR(handle)) 3553 return; 3554 3555 if (inode->i_size & (sb->s_blocksize - 1)) 3556 ext4_block_truncate_page(handle, mapping, inode->i_size); 3557 3558 if (ext4_orphan_add(handle, inode)) 3559 goto out_stop; 3560 3561 down_write(&EXT4_I(inode)->i_data_sem); 3562 ext4_ext_invalidate_cache(inode); 3563 3564 ext4_discard_preallocations(inode); 3565 3566 /* 3567 * TODO: optimization is possible here. 3568 * Probably we need not scan at all, 3569 * because page truncation is enough. 3570 */ 3571 3572 /* we have to know where to truncate from in crash case */ 3573 EXT4_I(inode)->i_disksize = inode->i_size; 3574 ext4_mark_inode_dirty(handle, inode); 3575 3576 last_block = (inode->i_size + sb->s_blocksize - 1) 3577 >> EXT4_BLOCK_SIZE_BITS(sb); 3578 err = ext4_ext_remove_space(inode, last_block); 3579 3580 /* In a multi-transaction truncate, we only make the final 3581 * transaction synchronous. 3582 */ 3583 if (IS_SYNC(inode)) 3584 ext4_handle_sync(handle); 3585 3586 out_stop: 3587 up_write(&EXT4_I(inode)->i_data_sem); 3588 /* 3589 * If this was a simple ftruncate() and the file will remain alive, 3590 * then we need to clear up the orphan record which we created above. 3591 * However, if this was a real unlink then we were called by 3592 * ext4_delete_inode(), and we allow that function to clean up the 3593 * orphan info for us. 3594 */ 3595 if (inode->i_nlink) 3596 ext4_orphan_del(handle, inode); 3597 3598 inode->i_mtime = inode->i_ctime = ext4_current_time(inode); 3599 ext4_mark_inode_dirty(handle, inode); 3600 ext4_journal_stop(handle); 3601 } 3602 3603 static void ext4_falloc_update_inode(struct inode *inode, 3604 int mode, loff_t new_size, int update_ctime) 3605 { 3606 struct timespec now; 3607 3608 if (update_ctime) { 3609 now = current_fs_time(inode->i_sb); 3610 if (!timespec_equal(&inode->i_ctime, &now)) 3611 inode->i_ctime = now; 3612 } 3613 /* 3614 * Update only when preallocation was requested beyond 3615 * the file size. 3616 */ 3617 if (!(mode & FALLOC_FL_KEEP_SIZE)) { 3618 if (new_size > i_size_read(inode)) 3619 i_size_write(inode, new_size); 3620 if (new_size > EXT4_I(inode)->i_disksize) 3621 ext4_update_i_disksize(inode, new_size); 3622 } else { 3623 /* 3624 * Mark that we allocate beyond EOF so the subsequent truncate 3625 * can proceed even if the new size is the same as i_size. 3626 */ 3627 if (new_size > i_size_read(inode)) 3628 EXT4_I(inode)->i_flags |= EXT4_EOFBLOCKS_FL; 3629 } 3630 3631 } 3632 3633 /* 3634 * preallocate space for a file. This implements ext4's fallocate inode 3635 * operation, which gets called from sys_fallocate system call. 3636 * For block-mapped files, posix_fallocate should fall back to the method 3637 * of writing zeroes to the required new blocks (the same behavior which is 3638 * expected for file systems which do not support fallocate() system call). 3639 */ 3640 long ext4_fallocate(struct inode *inode, int mode, loff_t offset, loff_t len) 3641 { 3642 handle_t *handle; 3643 ext4_lblk_t block; 3644 loff_t new_size; 3645 unsigned int max_blocks; 3646 int ret = 0; 3647 int ret2 = 0; 3648 int retries = 0; 3649 struct buffer_head map_bh; 3650 unsigned int credits, blkbits = inode->i_blkbits; 3651 3652 /* 3653 * currently supporting (pre)allocate mode for extent-based 3654 * files _only_ 3655 */ 3656 if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) 3657 return -EOPNOTSUPP; 3658 3659 /* preallocation to directories is currently not supported */ 3660 if (S_ISDIR(inode->i_mode)) 3661 return -ENODEV; 3662 3663 block = offset >> blkbits; 3664 /* 3665 * We can't just convert len to max_blocks because 3666 * If blocksize = 4096 offset = 3072 and len = 2048 3667 */ 3668 max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits) 3669 - block; 3670 /* 3671 * credits to insert 1 extent into extent tree 3672 */ 3673 credits = ext4_chunk_trans_blocks(inode, max_blocks); 3674 mutex_lock(&inode->i_mutex); 3675 retry: 3676 while (ret >= 0 && ret < max_blocks) { 3677 block = block + ret; 3678 max_blocks = max_blocks - ret; 3679 handle = ext4_journal_start(inode, credits); 3680 if (IS_ERR(handle)) { 3681 ret = PTR_ERR(handle); 3682 break; 3683 } 3684 map_bh.b_state = 0; 3685 ret = ext4_get_blocks(handle, inode, block, 3686 max_blocks, &map_bh, 3687 EXT4_GET_BLOCKS_CREATE_UNINIT_EXT); 3688 if (ret <= 0) { 3689 #ifdef EXT4FS_DEBUG 3690 WARN_ON(ret <= 0); 3691 printk(KERN_ERR "%s: ext4_ext_get_blocks " 3692 "returned error inode#%lu, block=%u, " 3693 "max_blocks=%u", __func__, 3694 inode->i_ino, block, max_blocks); 3695 #endif 3696 ext4_mark_inode_dirty(handle, inode); 3697 ret2 = ext4_journal_stop(handle); 3698 break; 3699 } 3700 if ((block + ret) >= (EXT4_BLOCK_ALIGN(offset + len, 3701 blkbits) >> blkbits)) 3702 new_size = offset + len; 3703 else 3704 new_size = (block + ret) << blkbits; 3705 3706 ext4_falloc_update_inode(inode, mode, new_size, 3707 buffer_new(&map_bh)); 3708 ext4_mark_inode_dirty(handle, inode); 3709 ret2 = ext4_journal_stop(handle); 3710 if (ret2) 3711 break; 3712 } 3713 if (ret == -ENOSPC && 3714 ext4_should_retry_alloc(inode->i_sb, &retries)) { 3715 ret = 0; 3716 goto retry; 3717 } 3718 mutex_unlock(&inode->i_mutex); 3719 return ret > 0 ? ret2 : ret; 3720 } 3721 3722 /* 3723 * This function convert a range of blocks to written extents 3724 * The caller of this function will pass the start offset and the size. 3725 * all unwritten extents within this range will be converted to 3726 * written extents. 3727 * 3728 * This function is called from the direct IO end io call back 3729 * function, to convert the fallocated extents after IO is completed. 3730 * Returns 0 on success. 3731 */ 3732 int ext4_convert_unwritten_extents(struct inode *inode, loff_t offset, 3733 ssize_t len) 3734 { 3735 handle_t *handle; 3736 ext4_lblk_t block; 3737 unsigned int max_blocks; 3738 int ret = 0; 3739 int ret2 = 0; 3740 struct buffer_head map_bh; 3741 unsigned int credits, blkbits = inode->i_blkbits; 3742 3743 block = offset >> blkbits; 3744 /* 3745 * We can't just convert len to max_blocks because 3746 * If blocksize = 4096 offset = 3072 and len = 2048 3747 */ 3748 max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits) 3749 - block; 3750 /* 3751 * credits to insert 1 extent into extent tree 3752 */ 3753 credits = ext4_chunk_trans_blocks(inode, max_blocks); 3754 while (ret >= 0 && ret < max_blocks) { 3755 block = block + ret; 3756 max_blocks = max_blocks - ret; 3757 handle = ext4_journal_start(inode, credits); 3758 if (IS_ERR(handle)) { 3759 ret = PTR_ERR(handle); 3760 break; 3761 } 3762 map_bh.b_state = 0; 3763 ret = ext4_get_blocks(handle, inode, block, 3764 max_blocks, &map_bh, 3765 EXT4_GET_BLOCKS_IO_CONVERT_EXT); 3766 if (ret <= 0) { 3767 WARN_ON(ret <= 0); 3768 printk(KERN_ERR "%s: ext4_ext_get_blocks " 3769 "returned error inode#%lu, block=%u, " 3770 "max_blocks=%u", __func__, 3771 inode->i_ino, block, max_blocks); 3772 } 3773 ext4_mark_inode_dirty(handle, inode); 3774 ret2 = ext4_journal_stop(handle); 3775 if (ret <= 0 || ret2 ) 3776 break; 3777 } 3778 return ret > 0 ? ret2 : ret; 3779 } 3780 /* 3781 * Callback function called for each extent to gather FIEMAP information. 3782 */ 3783 static int ext4_ext_fiemap_cb(struct inode *inode, struct ext4_ext_path *path, 3784 struct ext4_ext_cache *newex, struct ext4_extent *ex, 3785 void *data) 3786 { 3787 struct fiemap_extent_info *fieinfo = data; 3788 unsigned char blksize_bits = inode->i_sb->s_blocksize_bits; 3789 __u64 logical; 3790 __u64 physical; 3791 __u64 length; 3792 __u32 flags = 0; 3793 int error; 3794 3795 logical = (__u64)newex->ec_block << blksize_bits; 3796 3797 if (newex->ec_type == EXT4_EXT_CACHE_GAP) { 3798 pgoff_t offset; 3799 struct page *page; 3800 struct buffer_head *bh = NULL; 3801 3802 offset = logical >> PAGE_SHIFT; 3803 page = find_get_page(inode->i_mapping, offset); 3804 if (!page || !page_has_buffers(page)) 3805 return EXT_CONTINUE; 3806 3807 bh = page_buffers(page); 3808 3809 if (!bh) 3810 return EXT_CONTINUE; 3811 3812 if (buffer_delay(bh)) { 3813 flags |= FIEMAP_EXTENT_DELALLOC; 3814 page_cache_release(page); 3815 } else { 3816 page_cache_release(page); 3817 return EXT_CONTINUE; 3818 } 3819 } 3820 3821 physical = (__u64)newex->ec_start << blksize_bits; 3822 length = (__u64)newex->ec_len << blksize_bits; 3823 3824 if (ex && ext4_ext_is_uninitialized(ex)) 3825 flags |= FIEMAP_EXTENT_UNWRITTEN; 3826 3827 /* 3828 * If this extent reaches EXT_MAX_BLOCK, it must be last. 3829 * 3830 * Or if ext4_ext_next_allocated_block is EXT_MAX_BLOCK, 3831 * this also indicates no more allocated blocks. 3832 * 3833 * XXX this might miss a single-block extent at EXT_MAX_BLOCK 3834 */ 3835 if (ext4_ext_next_allocated_block(path) == EXT_MAX_BLOCK || 3836 newex->ec_block + newex->ec_len - 1 == EXT_MAX_BLOCK) { 3837 loff_t size = i_size_read(inode); 3838 loff_t bs = EXT4_BLOCK_SIZE(inode->i_sb); 3839 3840 flags |= FIEMAP_EXTENT_LAST; 3841 if ((flags & FIEMAP_EXTENT_DELALLOC) && 3842 logical+length > size) 3843 length = (size - logical + bs - 1) & ~(bs-1); 3844 } 3845 3846 error = fiemap_fill_next_extent(fieinfo, logical, physical, 3847 length, flags); 3848 if (error < 0) 3849 return error; 3850 if (error == 1) 3851 return EXT_BREAK; 3852 3853 return EXT_CONTINUE; 3854 } 3855 3856 /* fiemap flags we can handle specified here */ 3857 #define EXT4_FIEMAP_FLAGS (FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR) 3858 3859 static int ext4_xattr_fiemap(struct inode *inode, 3860 struct fiemap_extent_info *fieinfo) 3861 { 3862 __u64 physical = 0; 3863 __u64 length; 3864 __u32 flags = FIEMAP_EXTENT_LAST; 3865 int blockbits = inode->i_sb->s_blocksize_bits; 3866 int error = 0; 3867 3868 /* in-inode? */ 3869 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) { 3870 struct ext4_iloc iloc; 3871 int offset; /* offset of xattr in inode */ 3872 3873 error = ext4_get_inode_loc(inode, &iloc); 3874 if (error) 3875 return error; 3876 physical = iloc.bh->b_blocknr << blockbits; 3877 offset = EXT4_GOOD_OLD_INODE_SIZE + 3878 EXT4_I(inode)->i_extra_isize; 3879 physical += offset; 3880 length = EXT4_SB(inode->i_sb)->s_inode_size - offset; 3881 flags |= FIEMAP_EXTENT_DATA_INLINE; 3882 } else { /* external block */ 3883 physical = EXT4_I(inode)->i_file_acl << blockbits; 3884 length = inode->i_sb->s_blocksize; 3885 } 3886 3887 if (physical) 3888 error = fiemap_fill_next_extent(fieinfo, 0, physical, 3889 length, flags); 3890 return (error < 0 ? error : 0); 3891 } 3892 3893 int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, 3894 __u64 start, __u64 len) 3895 { 3896 ext4_lblk_t start_blk; 3897 int error = 0; 3898 3899 /* fallback to generic here if not in extents fmt */ 3900 if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) 3901 return generic_block_fiemap(inode, fieinfo, start, len, 3902 ext4_get_block); 3903 3904 if (fiemap_check_flags(fieinfo, EXT4_FIEMAP_FLAGS)) 3905 return -EBADR; 3906 3907 if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) { 3908 error = ext4_xattr_fiemap(inode, fieinfo); 3909 } else { 3910 ext4_lblk_t len_blks; 3911 __u64 last_blk; 3912 3913 start_blk = start >> inode->i_sb->s_blocksize_bits; 3914 last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits; 3915 if (last_blk >= EXT_MAX_BLOCK) 3916 last_blk = EXT_MAX_BLOCK-1; 3917 len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1; 3918 3919 /* 3920 * Walk the extent tree gathering extent information. 3921 * ext4_ext_fiemap_cb will push extents back to user. 3922 */ 3923 error = ext4_ext_walk_space(inode, start_blk, len_blks, 3924 ext4_ext_fiemap_cb, fieinfo); 3925 } 3926 3927 return error; 3928 } 3929 3930