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/fs.h> 33 #include <linux/time.h> 34 #include <linux/jbd2.h> 35 #include <linux/highuid.h> 36 #include <linux/pagemap.h> 37 #include <linux/quotaops.h> 38 #include <linux/string.h> 39 #include <linux/slab.h> 40 #include <linux/falloc.h> 41 #include <asm/uaccess.h> 42 #include <linux/fiemap.h> 43 #include "ext4_jbd2.h" 44 45 #include <trace/events/ext4.h> 46 47 /* 48 * used by extent splitting. 49 */ 50 #define EXT4_EXT_MAY_ZEROOUT 0x1 /* safe to zeroout if split fails \ 51 due to ENOSPC */ 52 #define EXT4_EXT_MARK_UNINIT1 0x2 /* mark first half uninitialized */ 53 #define EXT4_EXT_MARK_UNINIT2 0x4 /* mark second half uninitialized */ 54 55 static __le32 ext4_extent_block_csum(struct inode *inode, 56 struct ext4_extent_header *eh) 57 { 58 struct ext4_inode_info *ei = EXT4_I(inode); 59 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 60 __u32 csum; 61 62 csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)eh, 63 EXT4_EXTENT_TAIL_OFFSET(eh)); 64 return cpu_to_le32(csum); 65 } 66 67 static int ext4_extent_block_csum_verify(struct inode *inode, 68 struct ext4_extent_header *eh) 69 { 70 struct ext4_extent_tail *et; 71 72 if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb, 73 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) 74 return 1; 75 76 et = find_ext4_extent_tail(eh); 77 if (et->et_checksum != ext4_extent_block_csum(inode, eh)) 78 return 0; 79 return 1; 80 } 81 82 static void ext4_extent_block_csum_set(struct inode *inode, 83 struct ext4_extent_header *eh) 84 { 85 struct ext4_extent_tail *et; 86 87 if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb, 88 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) 89 return; 90 91 et = find_ext4_extent_tail(eh); 92 et->et_checksum = ext4_extent_block_csum(inode, eh); 93 } 94 95 static int ext4_split_extent(handle_t *handle, 96 struct inode *inode, 97 struct ext4_ext_path *path, 98 struct ext4_map_blocks *map, 99 int split_flag, 100 int flags); 101 102 static int ext4_split_extent_at(handle_t *handle, 103 struct inode *inode, 104 struct ext4_ext_path *path, 105 ext4_lblk_t split, 106 int split_flag, 107 int flags); 108 109 static int ext4_ext_truncate_extend_restart(handle_t *handle, 110 struct inode *inode, 111 int needed) 112 { 113 int err; 114 115 if (!ext4_handle_valid(handle)) 116 return 0; 117 if (handle->h_buffer_credits > needed) 118 return 0; 119 err = ext4_journal_extend(handle, needed); 120 if (err <= 0) 121 return err; 122 err = ext4_truncate_restart_trans(handle, inode, needed); 123 if (err == 0) 124 err = -EAGAIN; 125 126 return err; 127 } 128 129 /* 130 * could return: 131 * - EROFS 132 * - ENOMEM 133 */ 134 static int ext4_ext_get_access(handle_t *handle, struct inode *inode, 135 struct ext4_ext_path *path) 136 { 137 if (path->p_bh) { 138 /* path points to block */ 139 return ext4_journal_get_write_access(handle, path->p_bh); 140 } 141 /* path points to leaf/index in inode body */ 142 /* we use in-core data, no need to protect them */ 143 return 0; 144 } 145 146 /* 147 * could return: 148 * - EROFS 149 * - ENOMEM 150 * - EIO 151 */ 152 #define ext4_ext_dirty(handle, inode, path) \ 153 __ext4_ext_dirty(__func__, __LINE__, (handle), (inode), (path)) 154 static int __ext4_ext_dirty(const char *where, unsigned int line, 155 handle_t *handle, struct inode *inode, 156 struct ext4_ext_path *path) 157 { 158 int err; 159 if (path->p_bh) { 160 ext4_extent_block_csum_set(inode, ext_block_hdr(path->p_bh)); 161 /* path points to block */ 162 err = __ext4_handle_dirty_metadata(where, line, handle, 163 inode, path->p_bh); 164 } else { 165 /* path points to leaf/index in inode body */ 166 err = ext4_mark_inode_dirty(handle, inode); 167 } 168 return err; 169 } 170 171 static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode, 172 struct ext4_ext_path *path, 173 ext4_lblk_t block) 174 { 175 if (path) { 176 int depth = path->p_depth; 177 struct ext4_extent *ex; 178 179 /* 180 * Try to predict block placement assuming that we are 181 * filling in a file which will eventually be 182 * non-sparse --- i.e., in the case of libbfd writing 183 * an ELF object sections out-of-order but in a way 184 * the eventually results in a contiguous object or 185 * executable file, or some database extending a table 186 * space file. However, this is actually somewhat 187 * non-ideal if we are writing a sparse file such as 188 * qemu or KVM writing a raw image file that is going 189 * to stay fairly sparse, since it will end up 190 * fragmenting the file system's free space. Maybe we 191 * should have some hueristics or some way to allow 192 * userspace to pass a hint to file system, 193 * especially if the latter case turns out to be 194 * common. 195 */ 196 ex = path[depth].p_ext; 197 if (ex) { 198 ext4_fsblk_t ext_pblk = ext4_ext_pblock(ex); 199 ext4_lblk_t ext_block = le32_to_cpu(ex->ee_block); 200 201 if (block > ext_block) 202 return ext_pblk + (block - ext_block); 203 else 204 return ext_pblk - (ext_block - block); 205 } 206 207 /* it looks like index is empty; 208 * try to find starting block from index itself */ 209 if (path[depth].p_bh) 210 return path[depth].p_bh->b_blocknr; 211 } 212 213 /* OK. use inode's group */ 214 return ext4_inode_to_goal_block(inode); 215 } 216 217 /* 218 * Allocation for a meta data block 219 */ 220 static ext4_fsblk_t 221 ext4_ext_new_meta_block(handle_t *handle, struct inode *inode, 222 struct ext4_ext_path *path, 223 struct ext4_extent *ex, int *err, unsigned int flags) 224 { 225 ext4_fsblk_t goal, newblock; 226 227 goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block)); 228 newblock = ext4_new_meta_blocks(handle, inode, goal, flags, 229 NULL, err); 230 return newblock; 231 } 232 233 static inline int ext4_ext_space_block(struct inode *inode, int check) 234 { 235 int size; 236 237 size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header)) 238 / sizeof(struct ext4_extent); 239 #ifdef AGGRESSIVE_TEST 240 if (!check && size > 6) 241 size = 6; 242 #endif 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 #ifdef AGGRESSIVE_TEST 253 if (!check && size > 5) 254 size = 5; 255 #endif 256 return size; 257 } 258 259 static inline int ext4_ext_space_root(struct inode *inode, int check) 260 { 261 int size; 262 263 size = sizeof(EXT4_I(inode)->i_data); 264 size -= sizeof(struct ext4_extent_header); 265 size /= sizeof(struct ext4_extent); 266 #ifdef AGGRESSIVE_TEST 267 if (!check && size > 3) 268 size = 3; 269 #endif 270 return size; 271 } 272 273 static inline int ext4_ext_space_root_idx(struct inode *inode, int check) 274 { 275 int size; 276 277 size = sizeof(EXT4_I(inode)->i_data); 278 size -= sizeof(struct ext4_extent_header); 279 size /= sizeof(struct ext4_extent_idx); 280 #ifdef AGGRESSIVE_TEST 281 if (!check && size > 4) 282 size = 4; 283 #endif 284 return size; 285 } 286 287 /* 288 * Calculate the number of metadata blocks needed 289 * to allocate @blocks 290 * Worse case is one block per extent 291 */ 292 int ext4_ext_calc_metadata_amount(struct inode *inode, ext4_lblk_t lblock) 293 { 294 struct ext4_inode_info *ei = EXT4_I(inode); 295 int idxs; 296 297 idxs = ((inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header)) 298 / sizeof(struct ext4_extent_idx)); 299 300 /* 301 * If the new delayed allocation block is contiguous with the 302 * previous da block, it can share index blocks with the 303 * previous block, so we only need to allocate a new index 304 * block every idxs leaf blocks. At ldxs**2 blocks, we need 305 * an additional index block, and at ldxs**3 blocks, yet 306 * another index blocks. 307 */ 308 if (ei->i_da_metadata_calc_len && 309 ei->i_da_metadata_calc_last_lblock+1 == lblock) { 310 int num = 0; 311 312 if ((ei->i_da_metadata_calc_len % idxs) == 0) 313 num++; 314 if ((ei->i_da_metadata_calc_len % (idxs*idxs)) == 0) 315 num++; 316 if ((ei->i_da_metadata_calc_len % (idxs*idxs*idxs)) == 0) { 317 num++; 318 ei->i_da_metadata_calc_len = 0; 319 } else 320 ei->i_da_metadata_calc_len++; 321 ei->i_da_metadata_calc_last_lblock++; 322 return num; 323 } 324 325 /* 326 * In the worst case we need a new set of index blocks at 327 * every level of the inode's extent tree. 328 */ 329 ei->i_da_metadata_calc_len = 1; 330 ei->i_da_metadata_calc_last_lblock = lblock; 331 return ext_depth(inode) + 1; 332 } 333 334 static int 335 ext4_ext_max_entries(struct inode *inode, int depth) 336 { 337 int max; 338 339 if (depth == ext_depth(inode)) { 340 if (depth == 0) 341 max = ext4_ext_space_root(inode, 1); 342 else 343 max = ext4_ext_space_root_idx(inode, 1); 344 } else { 345 if (depth == 0) 346 max = ext4_ext_space_block(inode, 1); 347 else 348 max = ext4_ext_space_block_idx(inode, 1); 349 } 350 351 return max; 352 } 353 354 static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext) 355 { 356 ext4_fsblk_t block = ext4_ext_pblock(ext); 357 int len = ext4_ext_get_actual_len(ext); 358 359 if (len == 0) 360 return 0; 361 return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, len); 362 } 363 364 static int ext4_valid_extent_idx(struct inode *inode, 365 struct ext4_extent_idx *ext_idx) 366 { 367 ext4_fsblk_t block = ext4_idx_pblock(ext_idx); 368 369 return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, 1); 370 } 371 372 static int ext4_valid_extent_entries(struct inode *inode, 373 struct ext4_extent_header *eh, 374 int depth) 375 { 376 unsigned short entries; 377 if (eh->eh_entries == 0) 378 return 1; 379 380 entries = le16_to_cpu(eh->eh_entries); 381 382 if (depth == 0) { 383 /* leaf entries */ 384 struct ext4_extent *ext = EXT_FIRST_EXTENT(eh); 385 while (entries) { 386 if (!ext4_valid_extent(inode, ext)) 387 return 0; 388 ext++; 389 entries--; 390 } 391 } else { 392 struct ext4_extent_idx *ext_idx = EXT_FIRST_INDEX(eh); 393 while (entries) { 394 if (!ext4_valid_extent_idx(inode, ext_idx)) 395 return 0; 396 ext_idx++; 397 entries--; 398 } 399 } 400 return 1; 401 } 402 403 static int __ext4_ext_check(const char *function, unsigned int line, 404 struct inode *inode, struct ext4_extent_header *eh, 405 int depth) 406 { 407 const char *error_msg; 408 int max = 0; 409 410 if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) { 411 error_msg = "invalid magic"; 412 goto corrupted; 413 } 414 if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) { 415 error_msg = "unexpected eh_depth"; 416 goto corrupted; 417 } 418 if (unlikely(eh->eh_max == 0)) { 419 error_msg = "invalid eh_max"; 420 goto corrupted; 421 } 422 max = ext4_ext_max_entries(inode, depth); 423 if (unlikely(le16_to_cpu(eh->eh_max) > max)) { 424 error_msg = "too large eh_max"; 425 goto corrupted; 426 } 427 if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) { 428 error_msg = "invalid eh_entries"; 429 goto corrupted; 430 } 431 if (!ext4_valid_extent_entries(inode, eh, depth)) { 432 error_msg = "invalid extent entries"; 433 goto corrupted; 434 } 435 /* Verify checksum on non-root extent tree nodes */ 436 if (ext_depth(inode) != depth && 437 !ext4_extent_block_csum_verify(inode, eh)) { 438 error_msg = "extent tree corrupted"; 439 goto corrupted; 440 } 441 return 0; 442 443 corrupted: 444 ext4_error_inode(inode, function, line, 0, 445 "bad header/extent: %s - magic %x, " 446 "entries %u, max %u(%u), depth %u(%u)", 447 error_msg, le16_to_cpu(eh->eh_magic), 448 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max), 449 max, le16_to_cpu(eh->eh_depth), depth); 450 451 return -EIO; 452 } 453 454 #define ext4_ext_check(inode, eh, depth) \ 455 __ext4_ext_check(__func__, __LINE__, inode, eh, depth) 456 457 int ext4_ext_check_inode(struct inode *inode) 458 { 459 return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode)); 460 } 461 462 static int __ext4_ext_check_block(const char *function, unsigned int line, 463 struct inode *inode, 464 struct ext4_extent_header *eh, 465 int depth, 466 struct buffer_head *bh) 467 { 468 int ret; 469 470 if (buffer_verified(bh)) 471 return 0; 472 ret = ext4_ext_check(inode, eh, depth); 473 if (ret) 474 return ret; 475 set_buffer_verified(bh); 476 return ret; 477 } 478 479 #define ext4_ext_check_block(inode, eh, depth, bh) \ 480 __ext4_ext_check_block(__func__, __LINE__, inode, eh, depth, bh) 481 482 #ifdef EXT_DEBUG 483 static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path) 484 { 485 int k, l = path->p_depth; 486 487 ext_debug("path:"); 488 for (k = 0; k <= l; k++, path++) { 489 if (path->p_idx) { 490 ext_debug(" %d->%llu", le32_to_cpu(path->p_idx->ei_block), 491 ext4_idx_pblock(path->p_idx)); 492 } else if (path->p_ext) { 493 ext_debug(" %d:[%d]%d:%llu ", 494 le32_to_cpu(path->p_ext->ee_block), 495 ext4_ext_is_uninitialized(path->p_ext), 496 ext4_ext_get_actual_len(path->p_ext), 497 ext4_ext_pblock(path->p_ext)); 498 } else 499 ext_debug(" []"); 500 } 501 ext_debug("\n"); 502 } 503 504 static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path) 505 { 506 int depth = ext_depth(inode); 507 struct ext4_extent_header *eh; 508 struct ext4_extent *ex; 509 int i; 510 511 if (!path) 512 return; 513 514 eh = path[depth].p_hdr; 515 ex = EXT_FIRST_EXTENT(eh); 516 517 ext_debug("Displaying leaf extents for inode %lu\n", inode->i_ino); 518 519 for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) { 520 ext_debug("%d:[%d]%d:%llu ", le32_to_cpu(ex->ee_block), 521 ext4_ext_is_uninitialized(ex), 522 ext4_ext_get_actual_len(ex), ext4_ext_pblock(ex)); 523 } 524 ext_debug("\n"); 525 } 526 527 static void ext4_ext_show_move(struct inode *inode, struct ext4_ext_path *path, 528 ext4_fsblk_t newblock, int level) 529 { 530 int depth = ext_depth(inode); 531 struct ext4_extent *ex; 532 533 if (depth != level) { 534 struct ext4_extent_idx *idx; 535 idx = path[level].p_idx; 536 while (idx <= EXT_MAX_INDEX(path[level].p_hdr)) { 537 ext_debug("%d: move %d:%llu in new index %llu\n", level, 538 le32_to_cpu(idx->ei_block), 539 ext4_idx_pblock(idx), 540 newblock); 541 idx++; 542 } 543 544 return; 545 } 546 547 ex = path[depth].p_ext; 548 while (ex <= EXT_MAX_EXTENT(path[depth].p_hdr)) { 549 ext_debug("move %d:%llu:[%d]%d in new leaf %llu\n", 550 le32_to_cpu(ex->ee_block), 551 ext4_ext_pblock(ex), 552 ext4_ext_is_uninitialized(ex), 553 ext4_ext_get_actual_len(ex), 554 newblock); 555 ex++; 556 } 557 } 558 559 #else 560 #define ext4_ext_show_path(inode, path) 561 #define ext4_ext_show_leaf(inode, path) 562 #define ext4_ext_show_move(inode, path, newblock, level) 563 #endif 564 565 void ext4_ext_drop_refs(struct ext4_ext_path *path) 566 { 567 int depth = path->p_depth; 568 int i; 569 570 for (i = 0; i <= depth; i++, path++) 571 if (path->p_bh) { 572 brelse(path->p_bh); 573 path->p_bh = NULL; 574 } 575 } 576 577 /* 578 * ext4_ext_binsearch_idx: 579 * binary search for the closest index of the given block 580 * the header must be checked before calling this 581 */ 582 static void 583 ext4_ext_binsearch_idx(struct inode *inode, 584 struct ext4_ext_path *path, ext4_lblk_t block) 585 { 586 struct ext4_extent_header *eh = path->p_hdr; 587 struct ext4_extent_idx *r, *l, *m; 588 589 590 ext_debug("binsearch for %u(idx): ", block); 591 592 l = EXT_FIRST_INDEX(eh) + 1; 593 r = EXT_LAST_INDEX(eh); 594 while (l <= r) { 595 m = l + (r - l) / 2; 596 if (block < le32_to_cpu(m->ei_block)) 597 r = m - 1; 598 else 599 l = m + 1; 600 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ei_block), 601 m, le32_to_cpu(m->ei_block), 602 r, le32_to_cpu(r->ei_block)); 603 } 604 605 path->p_idx = l - 1; 606 ext_debug(" -> %u->%lld ", le32_to_cpu(path->p_idx->ei_block), 607 ext4_idx_pblock(path->p_idx)); 608 609 #ifdef CHECK_BINSEARCH 610 { 611 struct ext4_extent_idx *chix, *ix; 612 int k; 613 614 chix = ix = EXT_FIRST_INDEX(eh); 615 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) { 616 if (k != 0 && 617 le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) { 618 printk(KERN_DEBUG "k=%d, ix=0x%p, " 619 "first=0x%p\n", k, 620 ix, EXT_FIRST_INDEX(eh)); 621 printk(KERN_DEBUG "%u <= %u\n", 622 le32_to_cpu(ix->ei_block), 623 le32_to_cpu(ix[-1].ei_block)); 624 } 625 BUG_ON(k && le32_to_cpu(ix->ei_block) 626 <= le32_to_cpu(ix[-1].ei_block)); 627 if (block < le32_to_cpu(ix->ei_block)) 628 break; 629 chix = ix; 630 } 631 BUG_ON(chix != path->p_idx); 632 } 633 #endif 634 635 } 636 637 /* 638 * ext4_ext_binsearch: 639 * binary search for closest extent of the given block 640 * the header must be checked before calling this 641 */ 642 static void 643 ext4_ext_binsearch(struct inode *inode, 644 struct ext4_ext_path *path, ext4_lblk_t block) 645 { 646 struct ext4_extent_header *eh = path->p_hdr; 647 struct ext4_extent *r, *l, *m; 648 649 if (eh->eh_entries == 0) { 650 /* 651 * this leaf is empty: 652 * we get such a leaf in split/add case 653 */ 654 return; 655 } 656 657 ext_debug("binsearch for %u: ", block); 658 659 l = EXT_FIRST_EXTENT(eh) + 1; 660 r = EXT_LAST_EXTENT(eh); 661 662 while (l <= r) { 663 m = l + (r - l) / 2; 664 if (block < le32_to_cpu(m->ee_block)) 665 r = m - 1; 666 else 667 l = m + 1; 668 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ee_block), 669 m, le32_to_cpu(m->ee_block), 670 r, le32_to_cpu(r->ee_block)); 671 } 672 673 path->p_ext = l - 1; 674 ext_debug(" -> %d:%llu:[%d]%d ", 675 le32_to_cpu(path->p_ext->ee_block), 676 ext4_ext_pblock(path->p_ext), 677 ext4_ext_is_uninitialized(path->p_ext), 678 ext4_ext_get_actual_len(path->p_ext)); 679 680 #ifdef CHECK_BINSEARCH 681 { 682 struct ext4_extent *chex, *ex; 683 int k; 684 685 chex = ex = EXT_FIRST_EXTENT(eh); 686 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) { 687 BUG_ON(k && le32_to_cpu(ex->ee_block) 688 <= le32_to_cpu(ex[-1].ee_block)); 689 if (block < le32_to_cpu(ex->ee_block)) 690 break; 691 chex = ex; 692 } 693 BUG_ON(chex != path->p_ext); 694 } 695 #endif 696 697 } 698 699 int ext4_ext_tree_init(handle_t *handle, struct inode *inode) 700 { 701 struct ext4_extent_header *eh; 702 703 eh = ext_inode_hdr(inode); 704 eh->eh_depth = 0; 705 eh->eh_entries = 0; 706 eh->eh_magic = EXT4_EXT_MAGIC; 707 eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode, 0)); 708 ext4_mark_inode_dirty(handle, inode); 709 ext4_ext_invalidate_cache(inode); 710 return 0; 711 } 712 713 struct ext4_ext_path * 714 ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block, 715 struct ext4_ext_path *path) 716 { 717 struct ext4_extent_header *eh; 718 struct buffer_head *bh; 719 short int depth, i, ppos = 0, alloc = 0; 720 721 eh = ext_inode_hdr(inode); 722 depth = ext_depth(inode); 723 724 /* account possible depth increase */ 725 if (!path) { 726 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2), 727 GFP_NOFS); 728 if (!path) 729 return ERR_PTR(-ENOMEM); 730 alloc = 1; 731 } 732 path[0].p_hdr = eh; 733 path[0].p_bh = NULL; 734 735 i = depth; 736 /* walk through the tree */ 737 while (i) { 738 ext_debug("depth %d: num %d, max %d\n", 739 ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max)); 740 741 ext4_ext_binsearch_idx(inode, path + ppos, block); 742 path[ppos].p_block = ext4_idx_pblock(path[ppos].p_idx); 743 path[ppos].p_depth = i; 744 path[ppos].p_ext = NULL; 745 746 bh = sb_getblk(inode->i_sb, path[ppos].p_block); 747 if (unlikely(!bh)) 748 goto err; 749 if (!bh_uptodate_or_lock(bh)) { 750 trace_ext4_ext_load_extent(inode, block, 751 path[ppos].p_block); 752 if (bh_submit_read(bh) < 0) { 753 put_bh(bh); 754 goto err; 755 } 756 } 757 eh = ext_block_hdr(bh); 758 ppos++; 759 if (unlikely(ppos > depth)) { 760 put_bh(bh); 761 EXT4_ERROR_INODE(inode, 762 "ppos %d > depth %d", ppos, depth); 763 goto err; 764 } 765 path[ppos].p_bh = bh; 766 path[ppos].p_hdr = eh; 767 i--; 768 769 if (ext4_ext_check_block(inode, eh, i, bh)) 770 goto err; 771 } 772 773 path[ppos].p_depth = i; 774 path[ppos].p_ext = NULL; 775 path[ppos].p_idx = NULL; 776 777 /* find extent */ 778 ext4_ext_binsearch(inode, path + ppos, block); 779 /* if not an empty leaf */ 780 if (path[ppos].p_ext) 781 path[ppos].p_block = ext4_ext_pblock(path[ppos].p_ext); 782 783 ext4_ext_show_path(inode, path); 784 785 return path; 786 787 err: 788 ext4_ext_drop_refs(path); 789 if (alloc) 790 kfree(path); 791 return ERR_PTR(-EIO); 792 } 793 794 /* 795 * ext4_ext_insert_index: 796 * insert new index [@logical;@ptr] into the block at @curp; 797 * check where to insert: before @curp or after @curp 798 */ 799 static int ext4_ext_insert_index(handle_t *handle, struct inode *inode, 800 struct ext4_ext_path *curp, 801 int logical, ext4_fsblk_t ptr) 802 { 803 struct ext4_extent_idx *ix; 804 int len, err; 805 806 err = ext4_ext_get_access(handle, inode, curp); 807 if (err) 808 return err; 809 810 if (unlikely(logical == le32_to_cpu(curp->p_idx->ei_block))) { 811 EXT4_ERROR_INODE(inode, 812 "logical %d == ei_block %d!", 813 logical, le32_to_cpu(curp->p_idx->ei_block)); 814 return -EIO; 815 } 816 817 if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries) 818 >= le16_to_cpu(curp->p_hdr->eh_max))) { 819 EXT4_ERROR_INODE(inode, 820 "eh_entries %d >= eh_max %d!", 821 le16_to_cpu(curp->p_hdr->eh_entries), 822 le16_to_cpu(curp->p_hdr->eh_max)); 823 return -EIO; 824 } 825 826 if (logical > le32_to_cpu(curp->p_idx->ei_block)) { 827 /* insert after */ 828 ext_debug("insert new index %d after: %llu\n", logical, ptr); 829 ix = curp->p_idx + 1; 830 } else { 831 /* insert before */ 832 ext_debug("insert new index %d before: %llu\n", logical, ptr); 833 ix = curp->p_idx; 834 } 835 836 len = EXT_LAST_INDEX(curp->p_hdr) - ix + 1; 837 BUG_ON(len < 0); 838 if (len > 0) { 839 ext_debug("insert new index %d: " 840 "move %d indices from 0x%p to 0x%p\n", 841 logical, len, ix, ix + 1); 842 memmove(ix + 1, ix, len * sizeof(struct ext4_extent_idx)); 843 } 844 845 if (unlikely(ix > EXT_MAX_INDEX(curp->p_hdr))) { 846 EXT4_ERROR_INODE(inode, "ix > EXT_MAX_INDEX!"); 847 return -EIO; 848 } 849 850 ix->ei_block = cpu_to_le32(logical); 851 ext4_idx_store_pblock(ix, ptr); 852 le16_add_cpu(&curp->p_hdr->eh_entries, 1); 853 854 if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) { 855 EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!"); 856 return -EIO; 857 } 858 859 err = ext4_ext_dirty(handle, inode, curp); 860 ext4_std_error(inode->i_sb, err); 861 862 return err; 863 } 864 865 /* 866 * ext4_ext_split: 867 * inserts new subtree into the path, using free index entry 868 * at depth @at: 869 * - allocates all needed blocks (new leaf and all intermediate index blocks) 870 * - makes decision where to split 871 * - moves remaining extents and index entries (right to the split point) 872 * into the newly allocated blocks 873 * - initializes subtree 874 */ 875 static int ext4_ext_split(handle_t *handle, struct inode *inode, 876 unsigned int flags, 877 struct ext4_ext_path *path, 878 struct ext4_extent *newext, int at) 879 { 880 struct buffer_head *bh = NULL; 881 int depth = ext_depth(inode); 882 struct ext4_extent_header *neh; 883 struct ext4_extent_idx *fidx; 884 int i = at, k, m, a; 885 ext4_fsblk_t newblock, oldblock; 886 __le32 border; 887 ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */ 888 int err = 0; 889 890 /* make decision: where to split? */ 891 /* FIXME: now decision is simplest: at current extent */ 892 893 /* if current leaf will be split, then we should use 894 * border from split point */ 895 if (unlikely(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr))) { 896 EXT4_ERROR_INODE(inode, "p_ext > EXT_MAX_EXTENT!"); 897 return -EIO; 898 } 899 if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) { 900 border = path[depth].p_ext[1].ee_block; 901 ext_debug("leaf will be split." 902 " next leaf starts at %d\n", 903 le32_to_cpu(border)); 904 } else { 905 border = newext->ee_block; 906 ext_debug("leaf will be added." 907 " next leaf starts at %d\n", 908 le32_to_cpu(border)); 909 } 910 911 /* 912 * If error occurs, then we break processing 913 * and mark filesystem read-only. index won't 914 * be inserted and tree will be in consistent 915 * state. Next mount will repair buffers too. 916 */ 917 918 /* 919 * Get array to track all allocated blocks. 920 * We need this to handle errors and free blocks 921 * upon them. 922 */ 923 ablocks = kzalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS); 924 if (!ablocks) 925 return -ENOMEM; 926 927 /* allocate all needed blocks */ 928 ext_debug("allocate %d blocks for indexes/leaf\n", depth - at); 929 for (a = 0; a < depth - at; a++) { 930 newblock = ext4_ext_new_meta_block(handle, inode, path, 931 newext, &err, flags); 932 if (newblock == 0) 933 goto cleanup; 934 ablocks[a] = newblock; 935 } 936 937 /* initialize new leaf */ 938 newblock = ablocks[--a]; 939 if (unlikely(newblock == 0)) { 940 EXT4_ERROR_INODE(inode, "newblock == 0!"); 941 err = -EIO; 942 goto cleanup; 943 } 944 bh = sb_getblk(inode->i_sb, newblock); 945 if (!bh) { 946 err = -EIO; 947 goto cleanup; 948 } 949 lock_buffer(bh); 950 951 err = ext4_journal_get_create_access(handle, bh); 952 if (err) 953 goto cleanup; 954 955 neh = ext_block_hdr(bh); 956 neh->eh_entries = 0; 957 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0)); 958 neh->eh_magic = EXT4_EXT_MAGIC; 959 neh->eh_depth = 0; 960 961 /* move remainder of path[depth] to the new leaf */ 962 if (unlikely(path[depth].p_hdr->eh_entries != 963 path[depth].p_hdr->eh_max)) { 964 EXT4_ERROR_INODE(inode, "eh_entries %d != eh_max %d!", 965 path[depth].p_hdr->eh_entries, 966 path[depth].p_hdr->eh_max); 967 err = -EIO; 968 goto cleanup; 969 } 970 /* start copy from next extent */ 971 m = EXT_MAX_EXTENT(path[depth].p_hdr) - path[depth].p_ext++; 972 ext4_ext_show_move(inode, path, newblock, depth); 973 if (m) { 974 struct ext4_extent *ex; 975 ex = EXT_FIRST_EXTENT(neh); 976 memmove(ex, path[depth].p_ext, sizeof(struct ext4_extent) * m); 977 le16_add_cpu(&neh->eh_entries, m); 978 } 979 980 ext4_extent_block_csum_set(inode, neh); 981 set_buffer_uptodate(bh); 982 unlock_buffer(bh); 983 984 err = ext4_handle_dirty_metadata(handle, inode, bh); 985 if (err) 986 goto cleanup; 987 brelse(bh); 988 bh = NULL; 989 990 /* correct old leaf */ 991 if (m) { 992 err = ext4_ext_get_access(handle, inode, path + depth); 993 if (err) 994 goto cleanup; 995 le16_add_cpu(&path[depth].p_hdr->eh_entries, -m); 996 err = ext4_ext_dirty(handle, inode, path + depth); 997 if (err) 998 goto cleanup; 999 1000 } 1001 1002 /* create intermediate indexes */ 1003 k = depth - at - 1; 1004 if (unlikely(k < 0)) { 1005 EXT4_ERROR_INODE(inode, "k %d < 0!", k); 1006 err = -EIO; 1007 goto cleanup; 1008 } 1009 if (k) 1010 ext_debug("create %d intermediate indices\n", k); 1011 /* insert new index into current index block */ 1012 /* current depth stored in i var */ 1013 i = depth - 1; 1014 while (k--) { 1015 oldblock = newblock; 1016 newblock = ablocks[--a]; 1017 bh = sb_getblk(inode->i_sb, newblock); 1018 if (!bh) { 1019 err = -EIO; 1020 goto cleanup; 1021 } 1022 lock_buffer(bh); 1023 1024 err = ext4_journal_get_create_access(handle, bh); 1025 if (err) 1026 goto cleanup; 1027 1028 neh = ext_block_hdr(bh); 1029 neh->eh_entries = cpu_to_le16(1); 1030 neh->eh_magic = EXT4_EXT_MAGIC; 1031 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0)); 1032 neh->eh_depth = cpu_to_le16(depth - i); 1033 fidx = EXT_FIRST_INDEX(neh); 1034 fidx->ei_block = border; 1035 ext4_idx_store_pblock(fidx, oldblock); 1036 1037 ext_debug("int.index at %d (block %llu): %u -> %llu\n", 1038 i, newblock, le32_to_cpu(border), oldblock); 1039 1040 /* move remainder of path[i] to the new index block */ 1041 if (unlikely(EXT_MAX_INDEX(path[i].p_hdr) != 1042 EXT_LAST_INDEX(path[i].p_hdr))) { 1043 EXT4_ERROR_INODE(inode, 1044 "EXT_MAX_INDEX != EXT_LAST_INDEX ee_block %d!", 1045 le32_to_cpu(path[i].p_ext->ee_block)); 1046 err = -EIO; 1047 goto cleanup; 1048 } 1049 /* start copy indexes */ 1050 m = EXT_MAX_INDEX(path[i].p_hdr) - path[i].p_idx++; 1051 ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx, 1052 EXT_MAX_INDEX(path[i].p_hdr)); 1053 ext4_ext_show_move(inode, path, newblock, i); 1054 if (m) { 1055 memmove(++fidx, path[i].p_idx, 1056 sizeof(struct ext4_extent_idx) * m); 1057 le16_add_cpu(&neh->eh_entries, m); 1058 } 1059 ext4_extent_block_csum_set(inode, neh); 1060 set_buffer_uptodate(bh); 1061 unlock_buffer(bh); 1062 1063 err = ext4_handle_dirty_metadata(handle, inode, bh); 1064 if (err) 1065 goto cleanup; 1066 brelse(bh); 1067 bh = NULL; 1068 1069 /* correct old index */ 1070 if (m) { 1071 err = ext4_ext_get_access(handle, inode, path + i); 1072 if (err) 1073 goto cleanup; 1074 le16_add_cpu(&path[i].p_hdr->eh_entries, -m); 1075 err = ext4_ext_dirty(handle, inode, path + i); 1076 if (err) 1077 goto cleanup; 1078 } 1079 1080 i--; 1081 } 1082 1083 /* insert new index */ 1084 err = ext4_ext_insert_index(handle, inode, path + at, 1085 le32_to_cpu(border), newblock); 1086 1087 cleanup: 1088 if (bh) { 1089 if (buffer_locked(bh)) 1090 unlock_buffer(bh); 1091 brelse(bh); 1092 } 1093 1094 if (err) { 1095 /* free all allocated blocks in error case */ 1096 for (i = 0; i < depth; i++) { 1097 if (!ablocks[i]) 1098 continue; 1099 ext4_free_blocks(handle, inode, NULL, ablocks[i], 1, 1100 EXT4_FREE_BLOCKS_METADATA); 1101 } 1102 } 1103 kfree(ablocks); 1104 1105 return err; 1106 } 1107 1108 /* 1109 * ext4_ext_grow_indepth: 1110 * implements tree growing procedure: 1111 * - allocates new block 1112 * - moves top-level data (index block or leaf) into the new block 1113 * - initializes new top-level, creating index that points to the 1114 * just created block 1115 */ 1116 static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode, 1117 unsigned int flags, 1118 struct ext4_extent *newext) 1119 { 1120 struct ext4_extent_header *neh; 1121 struct buffer_head *bh; 1122 ext4_fsblk_t newblock; 1123 int err = 0; 1124 1125 newblock = ext4_ext_new_meta_block(handle, inode, NULL, 1126 newext, &err, flags); 1127 if (newblock == 0) 1128 return err; 1129 1130 bh = sb_getblk(inode->i_sb, newblock); 1131 if (!bh) { 1132 err = -EIO; 1133 ext4_std_error(inode->i_sb, err); 1134 return err; 1135 } 1136 lock_buffer(bh); 1137 1138 err = ext4_journal_get_create_access(handle, bh); 1139 if (err) { 1140 unlock_buffer(bh); 1141 goto out; 1142 } 1143 1144 /* move top-level index/leaf into new block */ 1145 memmove(bh->b_data, EXT4_I(inode)->i_data, 1146 sizeof(EXT4_I(inode)->i_data)); 1147 1148 /* set size of new block */ 1149 neh = ext_block_hdr(bh); 1150 /* old root could have indexes or leaves 1151 * so calculate e_max right way */ 1152 if (ext_depth(inode)) 1153 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0)); 1154 else 1155 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0)); 1156 neh->eh_magic = EXT4_EXT_MAGIC; 1157 ext4_extent_block_csum_set(inode, neh); 1158 set_buffer_uptodate(bh); 1159 unlock_buffer(bh); 1160 1161 err = ext4_handle_dirty_metadata(handle, inode, bh); 1162 if (err) 1163 goto out; 1164 1165 /* Update top-level index: num,max,pointer */ 1166 neh = ext_inode_hdr(inode); 1167 neh->eh_entries = cpu_to_le16(1); 1168 ext4_idx_store_pblock(EXT_FIRST_INDEX(neh), newblock); 1169 if (neh->eh_depth == 0) { 1170 /* Root extent block becomes index block */ 1171 neh->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode, 0)); 1172 EXT_FIRST_INDEX(neh)->ei_block = 1173 EXT_FIRST_EXTENT(neh)->ee_block; 1174 } 1175 ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n", 1176 le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max), 1177 le32_to_cpu(EXT_FIRST_INDEX(neh)->ei_block), 1178 ext4_idx_pblock(EXT_FIRST_INDEX(neh))); 1179 1180 neh->eh_depth = cpu_to_le16(le16_to_cpu(neh->eh_depth) + 1); 1181 ext4_mark_inode_dirty(handle, inode); 1182 out: 1183 brelse(bh); 1184 1185 return err; 1186 } 1187 1188 /* 1189 * ext4_ext_create_new_leaf: 1190 * finds empty index and adds new leaf. 1191 * if no free index is found, then it requests in-depth growing. 1192 */ 1193 static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode, 1194 unsigned int flags, 1195 struct ext4_ext_path *path, 1196 struct ext4_extent *newext) 1197 { 1198 struct ext4_ext_path *curp; 1199 int depth, i, err = 0; 1200 1201 repeat: 1202 i = depth = ext_depth(inode); 1203 1204 /* walk up to the tree and look for free index entry */ 1205 curp = path + depth; 1206 while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) { 1207 i--; 1208 curp--; 1209 } 1210 1211 /* we use already allocated block for index block, 1212 * so subsequent data blocks should be contiguous */ 1213 if (EXT_HAS_FREE_INDEX(curp)) { 1214 /* if we found index with free entry, then use that 1215 * entry: create all needed subtree and add new leaf */ 1216 err = ext4_ext_split(handle, inode, flags, path, newext, i); 1217 if (err) 1218 goto out; 1219 1220 /* refill path */ 1221 ext4_ext_drop_refs(path); 1222 path = ext4_ext_find_extent(inode, 1223 (ext4_lblk_t)le32_to_cpu(newext->ee_block), 1224 path); 1225 if (IS_ERR(path)) 1226 err = PTR_ERR(path); 1227 } else { 1228 /* tree is full, time to grow in depth */ 1229 err = ext4_ext_grow_indepth(handle, inode, flags, newext); 1230 if (err) 1231 goto out; 1232 1233 /* refill path */ 1234 ext4_ext_drop_refs(path); 1235 path = ext4_ext_find_extent(inode, 1236 (ext4_lblk_t)le32_to_cpu(newext->ee_block), 1237 path); 1238 if (IS_ERR(path)) { 1239 err = PTR_ERR(path); 1240 goto out; 1241 } 1242 1243 /* 1244 * only first (depth 0 -> 1) produces free space; 1245 * in all other cases we have to split the grown tree 1246 */ 1247 depth = ext_depth(inode); 1248 if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) { 1249 /* now we need to split */ 1250 goto repeat; 1251 } 1252 } 1253 1254 out: 1255 return err; 1256 } 1257 1258 /* 1259 * search the closest allocated block to the left for *logical 1260 * and returns it at @logical + it's physical address at @phys 1261 * if *logical is the smallest allocated block, the function 1262 * returns 0 at @phys 1263 * return value contains 0 (success) or error code 1264 */ 1265 static int ext4_ext_search_left(struct inode *inode, 1266 struct ext4_ext_path *path, 1267 ext4_lblk_t *logical, ext4_fsblk_t *phys) 1268 { 1269 struct ext4_extent_idx *ix; 1270 struct ext4_extent *ex; 1271 int depth, ee_len; 1272 1273 if (unlikely(path == NULL)) { 1274 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical); 1275 return -EIO; 1276 } 1277 depth = path->p_depth; 1278 *phys = 0; 1279 1280 if (depth == 0 && path->p_ext == NULL) 1281 return 0; 1282 1283 /* usually extent in the path covers blocks smaller 1284 * then *logical, but it can be that extent is the 1285 * first one in the file */ 1286 1287 ex = path[depth].p_ext; 1288 ee_len = ext4_ext_get_actual_len(ex); 1289 if (*logical < le32_to_cpu(ex->ee_block)) { 1290 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) { 1291 EXT4_ERROR_INODE(inode, 1292 "EXT_FIRST_EXTENT != ex *logical %d ee_block %d!", 1293 *logical, le32_to_cpu(ex->ee_block)); 1294 return -EIO; 1295 } 1296 while (--depth >= 0) { 1297 ix = path[depth].p_idx; 1298 if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) { 1299 EXT4_ERROR_INODE(inode, 1300 "ix (%d) != EXT_FIRST_INDEX (%d) (depth %d)!", 1301 ix != NULL ? le32_to_cpu(ix->ei_block) : 0, 1302 EXT_FIRST_INDEX(path[depth].p_hdr) != NULL ? 1303 le32_to_cpu(EXT_FIRST_INDEX(path[depth].p_hdr)->ei_block) : 0, 1304 depth); 1305 return -EIO; 1306 } 1307 } 1308 return 0; 1309 } 1310 1311 if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) { 1312 EXT4_ERROR_INODE(inode, 1313 "logical %d < ee_block %d + ee_len %d!", 1314 *logical, le32_to_cpu(ex->ee_block), ee_len); 1315 return -EIO; 1316 } 1317 1318 *logical = le32_to_cpu(ex->ee_block) + ee_len - 1; 1319 *phys = ext4_ext_pblock(ex) + ee_len - 1; 1320 return 0; 1321 } 1322 1323 /* 1324 * search the closest allocated block to the right for *logical 1325 * and returns it at @logical + it's physical address at @phys 1326 * if *logical is the largest allocated block, the function 1327 * returns 0 at @phys 1328 * return value contains 0 (success) or error code 1329 */ 1330 static int ext4_ext_search_right(struct inode *inode, 1331 struct ext4_ext_path *path, 1332 ext4_lblk_t *logical, ext4_fsblk_t *phys, 1333 struct ext4_extent **ret_ex) 1334 { 1335 struct buffer_head *bh = NULL; 1336 struct ext4_extent_header *eh; 1337 struct ext4_extent_idx *ix; 1338 struct ext4_extent *ex; 1339 ext4_fsblk_t block; 1340 int depth; /* Note, NOT eh_depth; depth from top of tree */ 1341 int ee_len; 1342 1343 if (unlikely(path == NULL)) { 1344 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical); 1345 return -EIO; 1346 } 1347 depth = path->p_depth; 1348 *phys = 0; 1349 1350 if (depth == 0 && path->p_ext == NULL) 1351 return 0; 1352 1353 /* usually extent in the path covers blocks smaller 1354 * then *logical, but it can be that extent is the 1355 * first one in the file */ 1356 1357 ex = path[depth].p_ext; 1358 ee_len = ext4_ext_get_actual_len(ex); 1359 if (*logical < le32_to_cpu(ex->ee_block)) { 1360 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) { 1361 EXT4_ERROR_INODE(inode, 1362 "first_extent(path[%d].p_hdr) != ex", 1363 depth); 1364 return -EIO; 1365 } 1366 while (--depth >= 0) { 1367 ix = path[depth].p_idx; 1368 if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) { 1369 EXT4_ERROR_INODE(inode, 1370 "ix != EXT_FIRST_INDEX *logical %d!", 1371 *logical); 1372 return -EIO; 1373 } 1374 } 1375 goto found_extent; 1376 } 1377 1378 if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) { 1379 EXT4_ERROR_INODE(inode, 1380 "logical %d < ee_block %d + ee_len %d!", 1381 *logical, le32_to_cpu(ex->ee_block), ee_len); 1382 return -EIO; 1383 } 1384 1385 if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) { 1386 /* next allocated block in this leaf */ 1387 ex++; 1388 goto found_extent; 1389 } 1390 1391 /* go up and search for index to the right */ 1392 while (--depth >= 0) { 1393 ix = path[depth].p_idx; 1394 if (ix != EXT_LAST_INDEX(path[depth].p_hdr)) 1395 goto got_index; 1396 } 1397 1398 /* we've gone up to the root and found no index to the right */ 1399 return 0; 1400 1401 got_index: 1402 /* we've found index to the right, let's 1403 * follow it and find the closest allocated 1404 * block to the right */ 1405 ix++; 1406 block = ext4_idx_pblock(ix); 1407 while (++depth < path->p_depth) { 1408 bh = sb_bread(inode->i_sb, block); 1409 if (bh == NULL) 1410 return -EIO; 1411 eh = ext_block_hdr(bh); 1412 /* subtract from p_depth to get proper eh_depth */ 1413 if (ext4_ext_check_block(inode, eh, 1414 path->p_depth - depth, bh)) { 1415 put_bh(bh); 1416 return -EIO; 1417 } 1418 ix = EXT_FIRST_INDEX(eh); 1419 block = ext4_idx_pblock(ix); 1420 put_bh(bh); 1421 } 1422 1423 bh = sb_bread(inode->i_sb, block); 1424 if (bh == NULL) 1425 return -EIO; 1426 eh = ext_block_hdr(bh); 1427 if (ext4_ext_check_block(inode, eh, path->p_depth - depth, bh)) { 1428 put_bh(bh); 1429 return -EIO; 1430 } 1431 ex = EXT_FIRST_EXTENT(eh); 1432 found_extent: 1433 *logical = le32_to_cpu(ex->ee_block); 1434 *phys = ext4_ext_pblock(ex); 1435 *ret_ex = ex; 1436 if (bh) 1437 put_bh(bh); 1438 return 0; 1439 } 1440 1441 /* 1442 * ext4_ext_next_allocated_block: 1443 * returns allocated block in subsequent extent or EXT_MAX_BLOCKS. 1444 * NOTE: it considers block number from index entry as 1445 * allocated block. Thus, index entries have to be consistent 1446 * with leaves. 1447 */ 1448 static ext4_lblk_t 1449 ext4_ext_next_allocated_block(struct ext4_ext_path *path) 1450 { 1451 int depth; 1452 1453 BUG_ON(path == NULL); 1454 depth = path->p_depth; 1455 1456 if (depth == 0 && path->p_ext == NULL) 1457 return EXT_MAX_BLOCKS; 1458 1459 while (depth >= 0) { 1460 if (depth == path->p_depth) { 1461 /* leaf */ 1462 if (path[depth].p_ext && 1463 path[depth].p_ext != 1464 EXT_LAST_EXTENT(path[depth].p_hdr)) 1465 return le32_to_cpu(path[depth].p_ext[1].ee_block); 1466 } else { 1467 /* index */ 1468 if (path[depth].p_idx != 1469 EXT_LAST_INDEX(path[depth].p_hdr)) 1470 return le32_to_cpu(path[depth].p_idx[1].ei_block); 1471 } 1472 depth--; 1473 } 1474 1475 return EXT_MAX_BLOCKS; 1476 } 1477 1478 /* 1479 * ext4_ext_next_leaf_block: 1480 * returns first allocated block from next leaf or EXT_MAX_BLOCKS 1481 */ 1482 static ext4_lblk_t ext4_ext_next_leaf_block(struct ext4_ext_path *path) 1483 { 1484 int depth; 1485 1486 BUG_ON(path == NULL); 1487 depth = path->p_depth; 1488 1489 /* zero-tree has no leaf blocks at all */ 1490 if (depth == 0) 1491 return EXT_MAX_BLOCKS; 1492 1493 /* go to index block */ 1494 depth--; 1495 1496 while (depth >= 0) { 1497 if (path[depth].p_idx != 1498 EXT_LAST_INDEX(path[depth].p_hdr)) 1499 return (ext4_lblk_t) 1500 le32_to_cpu(path[depth].p_idx[1].ei_block); 1501 depth--; 1502 } 1503 1504 return EXT_MAX_BLOCKS; 1505 } 1506 1507 /* 1508 * ext4_ext_correct_indexes: 1509 * if leaf gets modified and modified extent is first in the leaf, 1510 * then we have to correct all indexes above. 1511 * TODO: do we need to correct tree in all cases? 1512 */ 1513 static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode, 1514 struct ext4_ext_path *path) 1515 { 1516 struct ext4_extent_header *eh; 1517 int depth = ext_depth(inode); 1518 struct ext4_extent *ex; 1519 __le32 border; 1520 int k, err = 0; 1521 1522 eh = path[depth].p_hdr; 1523 ex = path[depth].p_ext; 1524 1525 if (unlikely(ex == NULL || eh == NULL)) { 1526 EXT4_ERROR_INODE(inode, 1527 "ex %p == NULL or eh %p == NULL", ex, eh); 1528 return -EIO; 1529 } 1530 1531 if (depth == 0) { 1532 /* there is no tree at all */ 1533 return 0; 1534 } 1535 1536 if (ex != EXT_FIRST_EXTENT(eh)) { 1537 /* we correct tree if first leaf got modified only */ 1538 return 0; 1539 } 1540 1541 /* 1542 * TODO: we need correction if border is smaller than current one 1543 */ 1544 k = depth - 1; 1545 border = path[depth].p_ext->ee_block; 1546 err = ext4_ext_get_access(handle, inode, path + k); 1547 if (err) 1548 return err; 1549 path[k].p_idx->ei_block = border; 1550 err = ext4_ext_dirty(handle, inode, path + k); 1551 if (err) 1552 return err; 1553 1554 while (k--) { 1555 /* change all left-side indexes */ 1556 if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr)) 1557 break; 1558 err = ext4_ext_get_access(handle, inode, path + k); 1559 if (err) 1560 break; 1561 path[k].p_idx->ei_block = border; 1562 err = ext4_ext_dirty(handle, inode, path + k); 1563 if (err) 1564 break; 1565 } 1566 1567 return err; 1568 } 1569 1570 int 1571 ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1, 1572 struct ext4_extent *ex2) 1573 { 1574 unsigned short ext1_ee_len, ext2_ee_len, max_len; 1575 1576 /* 1577 * Make sure that either both extents are uninitialized, or 1578 * both are _not_. 1579 */ 1580 if (ext4_ext_is_uninitialized(ex1) ^ ext4_ext_is_uninitialized(ex2)) 1581 return 0; 1582 1583 if (ext4_ext_is_uninitialized(ex1)) 1584 max_len = EXT_UNINIT_MAX_LEN; 1585 else 1586 max_len = EXT_INIT_MAX_LEN; 1587 1588 ext1_ee_len = ext4_ext_get_actual_len(ex1); 1589 ext2_ee_len = ext4_ext_get_actual_len(ex2); 1590 1591 if (le32_to_cpu(ex1->ee_block) + ext1_ee_len != 1592 le32_to_cpu(ex2->ee_block)) 1593 return 0; 1594 1595 /* 1596 * To allow future support for preallocated extents to be added 1597 * as an RO_COMPAT feature, refuse to merge to extents if 1598 * this can result in the top bit of ee_len being set. 1599 */ 1600 if (ext1_ee_len + ext2_ee_len > max_len) 1601 return 0; 1602 #ifdef AGGRESSIVE_TEST 1603 if (ext1_ee_len >= 4) 1604 return 0; 1605 #endif 1606 1607 if (ext4_ext_pblock(ex1) + ext1_ee_len == ext4_ext_pblock(ex2)) 1608 return 1; 1609 return 0; 1610 } 1611 1612 /* 1613 * This function tries to merge the "ex" extent to the next extent in the tree. 1614 * It always tries to merge towards right. If you want to merge towards 1615 * left, pass "ex - 1" as argument instead of "ex". 1616 * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns 1617 * 1 if they got merged. 1618 */ 1619 static int ext4_ext_try_to_merge_right(struct inode *inode, 1620 struct ext4_ext_path *path, 1621 struct ext4_extent *ex) 1622 { 1623 struct ext4_extent_header *eh; 1624 unsigned int depth, len; 1625 int merge_done = 0; 1626 int uninitialized = 0; 1627 1628 depth = ext_depth(inode); 1629 BUG_ON(path[depth].p_hdr == NULL); 1630 eh = path[depth].p_hdr; 1631 1632 while (ex < EXT_LAST_EXTENT(eh)) { 1633 if (!ext4_can_extents_be_merged(inode, ex, ex + 1)) 1634 break; 1635 /* merge with next extent! */ 1636 if (ext4_ext_is_uninitialized(ex)) 1637 uninitialized = 1; 1638 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex) 1639 + ext4_ext_get_actual_len(ex + 1)); 1640 if (uninitialized) 1641 ext4_ext_mark_uninitialized(ex); 1642 1643 if (ex + 1 < EXT_LAST_EXTENT(eh)) { 1644 len = (EXT_LAST_EXTENT(eh) - ex - 1) 1645 * sizeof(struct ext4_extent); 1646 memmove(ex + 1, ex + 2, len); 1647 } 1648 le16_add_cpu(&eh->eh_entries, -1); 1649 merge_done = 1; 1650 WARN_ON(eh->eh_entries == 0); 1651 if (!eh->eh_entries) 1652 EXT4_ERROR_INODE(inode, "eh->eh_entries = 0!"); 1653 } 1654 1655 return merge_done; 1656 } 1657 1658 /* 1659 * This function tries to merge the @ex extent to neighbours in the tree. 1660 * return 1 if merge left else 0. 1661 */ 1662 static int ext4_ext_try_to_merge(struct inode *inode, 1663 struct ext4_ext_path *path, 1664 struct ext4_extent *ex) { 1665 struct ext4_extent_header *eh; 1666 unsigned int depth; 1667 int merge_done = 0; 1668 int ret = 0; 1669 1670 depth = ext_depth(inode); 1671 BUG_ON(path[depth].p_hdr == NULL); 1672 eh = path[depth].p_hdr; 1673 1674 if (ex > EXT_FIRST_EXTENT(eh)) 1675 merge_done = ext4_ext_try_to_merge_right(inode, path, ex - 1); 1676 1677 if (!merge_done) 1678 ret = ext4_ext_try_to_merge_right(inode, path, ex); 1679 1680 return ret; 1681 } 1682 1683 /* 1684 * check if a portion of the "newext" extent overlaps with an 1685 * existing extent. 1686 * 1687 * If there is an overlap discovered, it updates the length of the newext 1688 * such that there will be no overlap, and then returns 1. 1689 * If there is no overlap found, it returns 0. 1690 */ 1691 static unsigned int ext4_ext_check_overlap(struct ext4_sb_info *sbi, 1692 struct inode *inode, 1693 struct ext4_extent *newext, 1694 struct ext4_ext_path *path) 1695 { 1696 ext4_lblk_t b1, b2; 1697 unsigned int depth, len1; 1698 unsigned int ret = 0; 1699 1700 b1 = le32_to_cpu(newext->ee_block); 1701 len1 = ext4_ext_get_actual_len(newext); 1702 depth = ext_depth(inode); 1703 if (!path[depth].p_ext) 1704 goto out; 1705 b2 = le32_to_cpu(path[depth].p_ext->ee_block); 1706 b2 &= ~(sbi->s_cluster_ratio - 1); 1707 1708 /* 1709 * get the next allocated block if the extent in the path 1710 * is before the requested block(s) 1711 */ 1712 if (b2 < b1) { 1713 b2 = ext4_ext_next_allocated_block(path); 1714 if (b2 == EXT_MAX_BLOCKS) 1715 goto out; 1716 b2 &= ~(sbi->s_cluster_ratio - 1); 1717 } 1718 1719 /* check for wrap through zero on extent logical start block*/ 1720 if (b1 + len1 < b1) { 1721 len1 = EXT_MAX_BLOCKS - b1; 1722 newext->ee_len = cpu_to_le16(len1); 1723 ret = 1; 1724 } 1725 1726 /* check for overlap */ 1727 if (b1 + len1 > b2) { 1728 newext->ee_len = cpu_to_le16(b2 - b1); 1729 ret = 1; 1730 } 1731 out: 1732 return ret; 1733 } 1734 1735 /* 1736 * ext4_ext_insert_extent: 1737 * tries to merge requsted extent into the existing extent or 1738 * inserts requested extent as new one into the tree, 1739 * creating new leaf in the no-space case. 1740 */ 1741 int ext4_ext_insert_extent(handle_t *handle, struct inode *inode, 1742 struct ext4_ext_path *path, 1743 struct ext4_extent *newext, int flag) 1744 { 1745 struct ext4_extent_header *eh; 1746 struct ext4_extent *ex, *fex; 1747 struct ext4_extent *nearex; /* nearest extent */ 1748 struct ext4_ext_path *npath = NULL; 1749 int depth, len, err; 1750 ext4_lblk_t next; 1751 unsigned uninitialized = 0; 1752 int flags = 0; 1753 1754 if (unlikely(ext4_ext_get_actual_len(newext) == 0)) { 1755 EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0"); 1756 return -EIO; 1757 } 1758 depth = ext_depth(inode); 1759 ex = path[depth].p_ext; 1760 if (unlikely(path[depth].p_hdr == NULL)) { 1761 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth); 1762 return -EIO; 1763 } 1764 1765 /* try to insert block into found extent and return */ 1766 if (ex && !(flag & EXT4_GET_BLOCKS_PRE_IO) 1767 && ext4_can_extents_be_merged(inode, ex, newext)) { 1768 ext_debug("append [%d]%d block to %u:[%d]%d (from %llu)\n", 1769 ext4_ext_is_uninitialized(newext), 1770 ext4_ext_get_actual_len(newext), 1771 le32_to_cpu(ex->ee_block), 1772 ext4_ext_is_uninitialized(ex), 1773 ext4_ext_get_actual_len(ex), 1774 ext4_ext_pblock(ex)); 1775 err = ext4_ext_get_access(handle, inode, path + depth); 1776 if (err) 1777 return err; 1778 1779 /* 1780 * ext4_can_extents_be_merged should have checked that either 1781 * both extents are uninitialized, or both aren't. Thus we 1782 * need to check only one of them here. 1783 */ 1784 if (ext4_ext_is_uninitialized(ex)) 1785 uninitialized = 1; 1786 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex) 1787 + ext4_ext_get_actual_len(newext)); 1788 if (uninitialized) 1789 ext4_ext_mark_uninitialized(ex); 1790 eh = path[depth].p_hdr; 1791 nearex = ex; 1792 goto merge; 1793 } 1794 1795 depth = ext_depth(inode); 1796 eh = path[depth].p_hdr; 1797 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) 1798 goto has_space; 1799 1800 /* probably next leaf has space for us? */ 1801 fex = EXT_LAST_EXTENT(eh); 1802 next = EXT_MAX_BLOCKS; 1803 if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block)) 1804 next = ext4_ext_next_leaf_block(path); 1805 if (next != EXT_MAX_BLOCKS) { 1806 ext_debug("next leaf block - %u\n", next); 1807 BUG_ON(npath != NULL); 1808 npath = ext4_ext_find_extent(inode, next, NULL); 1809 if (IS_ERR(npath)) 1810 return PTR_ERR(npath); 1811 BUG_ON(npath->p_depth != path->p_depth); 1812 eh = npath[depth].p_hdr; 1813 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) { 1814 ext_debug("next leaf isn't full(%d)\n", 1815 le16_to_cpu(eh->eh_entries)); 1816 path = npath; 1817 goto has_space; 1818 } 1819 ext_debug("next leaf has no free space(%d,%d)\n", 1820 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max)); 1821 } 1822 1823 /* 1824 * There is no free space in the found leaf. 1825 * We're gonna add a new leaf in the tree. 1826 */ 1827 if (flag & EXT4_GET_BLOCKS_PUNCH_OUT_EXT) 1828 flags = EXT4_MB_USE_ROOT_BLOCKS; 1829 err = ext4_ext_create_new_leaf(handle, inode, flags, path, newext); 1830 if (err) 1831 goto cleanup; 1832 depth = ext_depth(inode); 1833 eh = path[depth].p_hdr; 1834 1835 has_space: 1836 nearex = path[depth].p_ext; 1837 1838 err = ext4_ext_get_access(handle, inode, path + depth); 1839 if (err) 1840 goto cleanup; 1841 1842 if (!nearex) { 1843 /* there is no extent in this leaf, create first one */ 1844 ext_debug("first extent in the leaf: %u:%llu:[%d]%d\n", 1845 le32_to_cpu(newext->ee_block), 1846 ext4_ext_pblock(newext), 1847 ext4_ext_is_uninitialized(newext), 1848 ext4_ext_get_actual_len(newext)); 1849 nearex = EXT_FIRST_EXTENT(eh); 1850 } else { 1851 if (le32_to_cpu(newext->ee_block) 1852 > le32_to_cpu(nearex->ee_block)) { 1853 /* Insert after */ 1854 ext_debug("insert %u:%llu:[%d]%d before: " 1855 "nearest %p\n", 1856 le32_to_cpu(newext->ee_block), 1857 ext4_ext_pblock(newext), 1858 ext4_ext_is_uninitialized(newext), 1859 ext4_ext_get_actual_len(newext), 1860 nearex); 1861 nearex++; 1862 } else { 1863 /* Insert before */ 1864 BUG_ON(newext->ee_block == nearex->ee_block); 1865 ext_debug("insert %u:%llu:[%d]%d after: " 1866 "nearest %p\n", 1867 le32_to_cpu(newext->ee_block), 1868 ext4_ext_pblock(newext), 1869 ext4_ext_is_uninitialized(newext), 1870 ext4_ext_get_actual_len(newext), 1871 nearex); 1872 } 1873 len = EXT_LAST_EXTENT(eh) - nearex + 1; 1874 if (len > 0) { 1875 ext_debug("insert %u:%llu:[%d]%d: " 1876 "move %d extents from 0x%p to 0x%p\n", 1877 le32_to_cpu(newext->ee_block), 1878 ext4_ext_pblock(newext), 1879 ext4_ext_is_uninitialized(newext), 1880 ext4_ext_get_actual_len(newext), 1881 len, nearex, nearex + 1); 1882 memmove(nearex + 1, nearex, 1883 len * sizeof(struct ext4_extent)); 1884 } 1885 } 1886 1887 le16_add_cpu(&eh->eh_entries, 1); 1888 path[depth].p_ext = nearex; 1889 nearex->ee_block = newext->ee_block; 1890 ext4_ext_store_pblock(nearex, ext4_ext_pblock(newext)); 1891 nearex->ee_len = newext->ee_len; 1892 1893 merge: 1894 /* try to merge extents */ 1895 if (!(flag & EXT4_GET_BLOCKS_PRE_IO)) 1896 ext4_ext_try_to_merge(inode, path, nearex); 1897 1898 1899 /* time to correct all indexes above */ 1900 err = ext4_ext_correct_indexes(handle, inode, path); 1901 if (err) 1902 goto cleanup; 1903 1904 err = ext4_ext_dirty(handle, inode, path + depth); 1905 1906 cleanup: 1907 if (npath) { 1908 ext4_ext_drop_refs(npath); 1909 kfree(npath); 1910 } 1911 ext4_ext_invalidate_cache(inode); 1912 return err; 1913 } 1914 1915 static int ext4_ext_walk_space(struct inode *inode, ext4_lblk_t block, 1916 ext4_lblk_t num, ext_prepare_callback func, 1917 void *cbdata) 1918 { 1919 struct ext4_ext_path *path = NULL; 1920 struct ext4_ext_cache cbex; 1921 struct ext4_extent *ex; 1922 ext4_lblk_t next, start = 0, end = 0; 1923 ext4_lblk_t last = block + num; 1924 int depth, exists, err = 0; 1925 1926 BUG_ON(func == NULL); 1927 BUG_ON(inode == NULL); 1928 1929 while (block < last && block != EXT_MAX_BLOCKS) { 1930 num = last - block; 1931 /* find extent for this block */ 1932 down_read(&EXT4_I(inode)->i_data_sem); 1933 path = ext4_ext_find_extent(inode, block, path); 1934 up_read(&EXT4_I(inode)->i_data_sem); 1935 if (IS_ERR(path)) { 1936 err = PTR_ERR(path); 1937 path = NULL; 1938 break; 1939 } 1940 1941 depth = ext_depth(inode); 1942 if (unlikely(path[depth].p_hdr == NULL)) { 1943 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth); 1944 err = -EIO; 1945 break; 1946 } 1947 ex = path[depth].p_ext; 1948 next = ext4_ext_next_allocated_block(path); 1949 1950 exists = 0; 1951 if (!ex) { 1952 /* there is no extent yet, so try to allocate 1953 * all requested space */ 1954 start = block; 1955 end = block + num; 1956 } else if (le32_to_cpu(ex->ee_block) > block) { 1957 /* need to allocate space before found extent */ 1958 start = block; 1959 end = le32_to_cpu(ex->ee_block); 1960 if (block + num < end) 1961 end = block + num; 1962 } else if (block >= le32_to_cpu(ex->ee_block) 1963 + ext4_ext_get_actual_len(ex)) { 1964 /* need to allocate space after found extent */ 1965 start = block; 1966 end = block + num; 1967 if (end >= next) 1968 end = next; 1969 } else if (block >= le32_to_cpu(ex->ee_block)) { 1970 /* 1971 * some part of requested space is covered 1972 * by found extent 1973 */ 1974 start = block; 1975 end = le32_to_cpu(ex->ee_block) 1976 + ext4_ext_get_actual_len(ex); 1977 if (block + num < end) 1978 end = block + num; 1979 exists = 1; 1980 } else { 1981 BUG(); 1982 } 1983 BUG_ON(end <= start); 1984 1985 if (!exists) { 1986 cbex.ec_block = start; 1987 cbex.ec_len = end - start; 1988 cbex.ec_start = 0; 1989 } else { 1990 cbex.ec_block = le32_to_cpu(ex->ee_block); 1991 cbex.ec_len = ext4_ext_get_actual_len(ex); 1992 cbex.ec_start = ext4_ext_pblock(ex); 1993 } 1994 1995 if (unlikely(cbex.ec_len == 0)) { 1996 EXT4_ERROR_INODE(inode, "cbex.ec_len == 0"); 1997 err = -EIO; 1998 break; 1999 } 2000 err = func(inode, next, &cbex, ex, cbdata); 2001 ext4_ext_drop_refs(path); 2002 2003 if (err < 0) 2004 break; 2005 2006 if (err == EXT_REPEAT) 2007 continue; 2008 else if (err == EXT_BREAK) { 2009 err = 0; 2010 break; 2011 } 2012 2013 if (ext_depth(inode) != depth) { 2014 /* depth was changed. we have to realloc path */ 2015 kfree(path); 2016 path = NULL; 2017 } 2018 2019 block = cbex.ec_block + cbex.ec_len; 2020 } 2021 2022 if (path) { 2023 ext4_ext_drop_refs(path); 2024 kfree(path); 2025 } 2026 2027 return err; 2028 } 2029 2030 static void 2031 ext4_ext_put_in_cache(struct inode *inode, ext4_lblk_t block, 2032 __u32 len, ext4_fsblk_t start) 2033 { 2034 struct ext4_ext_cache *cex; 2035 BUG_ON(len == 0); 2036 spin_lock(&EXT4_I(inode)->i_block_reservation_lock); 2037 trace_ext4_ext_put_in_cache(inode, block, len, start); 2038 cex = &EXT4_I(inode)->i_cached_extent; 2039 cex->ec_block = block; 2040 cex->ec_len = len; 2041 cex->ec_start = start; 2042 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock); 2043 } 2044 2045 /* 2046 * ext4_ext_put_gap_in_cache: 2047 * calculate boundaries of the gap that the requested block fits into 2048 * and cache this gap 2049 */ 2050 static void 2051 ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path, 2052 ext4_lblk_t block) 2053 { 2054 int depth = ext_depth(inode); 2055 unsigned long len; 2056 ext4_lblk_t lblock; 2057 struct ext4_extent *ex; 2058 2059 ex = path[depth].p_ext; 2060 if (ex == NULL) { 2061 /* there is no extent yet, so gap is [0;-] */ 2062 lblock = 0; 2063 len = EXT_MAX_BLOCKS; 2064 ext_debug("cache gap(whole file):"); 2065 } else if (block < le32_to_cpu(ex->ee_block)) { 2066 lblock = block; 2067 len = le32_to_cpu(ex->ee_block) - block; 2068 ext_debug("cache gap(before): %u [%u:%u]", 2069 block, 2070 le32_to_cpu(ex->ee_block), 2071 ext4_ext_get_actual_len(ex)); 2072 } else if (block >= le32_to_cpu(ex->ee_block) 2073 + ext4_ext_get_actual_len(ex)) { 2074 ext4_lblk_t next; 2075 lblock = le32_to_cpu(ex->ee_block) 2076 + ext4_ext_get_actual_len(ex); 2077 2078 next = ext4_ext_next_allocated_block(path); 2079 ext_debug("cache gap(after): [%u:%u] %u", 2080 le32_to_cpu(ex->ee_block), 2081 ext4_ext_get_actual_len(ex), 2082 block); 2083 BUG_ON(next == lblock); 2084 len = next - lblock; 2085 } else { 2086 lblock = len = 0; 2087 BUG(); 2088 } 2089 2090 ext_debug(" -> %u:%lu\n", lblock, len); 2091 ext4_ext_put_in_cache(inode, lblock, len, 0); 2092 } 2093 2094 /* 2095 * ext4_ext_check_cache() 2096 * Checks to see if the given block is in the cache. 2097 * If it is, the cached extent is stored in the given 2098 * cache extent pointer. If the cached extent is a hole, 2099 * this routine should be used instead of 2100 * ext4_ext_in_cache if the calling function needs to 2101 * know the size of the hole. 2102 * 2103 * @inode: The files inode 2104 * @block: The block to look for in the cache 2105 * @ex: Pointer where the cached extent will be stored 2106 * if it contains block 2107 * 2108 * Return 0 if cache is invalid; 1 if the cache is valid 2109 */ 2110 static int ext4_ext_check_cache(struct inode *inode, ext4_lblk_t block, 2111 struct ext4_ext_cache *ex){ 2112 struct ext4_ext_cache *cex; 2113 struct ext4_sb_info *sbi; 2114 int ret = 0; 2115 2116 /* 2117 * We borrow i_block_reservation_lock to protect i_cached_extent 2118 */ 2119 spin_lock(&EXT4_I(inode)->i_block_reservation_lock); 2120 cex = &EXT4_I(inode)->i_cached_extent; 2121 sbi = EXT4_SB(inode->i_sb); 2122 2123 /* has cache valid data? */ 2124 if (cex->ec_len == 0) 2125 goto errout; 2126 2127 if (in_range(block, cex->ec_block, cex->ec_len)) { 2128 memcpy(ex, cex, sizeof(struct ext4_ext_cache)); 2129 ext_debug("%u cached by %u:%u:%llu\n", 2130 block, 2131 cex->ec_block, cex->ec_len, cex->ec_start); 2132 ret = 1; 2133 } 2134 errout: 2135 trace_ext4_ext_in_cache(inode, block, ret); 2136 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock); 2137 return ret; 2138 } 2139 2140 /* 2141 * ext4_ext_in_cache() 2142 * Checks to see if the given block is in the cache. 2143 * If it is, the cached extent is stored in the given 2144 * extent pointer. 2145 * 2146 * @inode: The files inode 2147 * @block: The block to look for in the cache 2148 * @ex: Pointer where the cached extent will be stored 2149 * if it contains block 2150 * 2151 * Return 0 if cache is invalid; 1 if the cache is valid 2152 */ 2153 static int 2154 ext4_ext_in_cache(struct inode *inode, ext4_lblk_t block, 2155 struct ext4_extent *ex) 2156 { 2157 struct ext4_ext_cache cex; 2158 int ret = 0; 2159 2160 if (ext4_ext_check_cache(inode, block, &cex)) { 2161 ex->ee_block = cpu_to_le32(cex.ec_block); 2162 ext4_ext_store_pblock(ex, cex.ec_start); 2163 ex->ee_len = cpu_to_le16(cex.ec_len); 2164 ret = 1; 2165 } 2166 2167 return ret; 2168 } 2169 2170 2171 /* 2172 * ext4_ext_rm_idx: 2173 * removes index from the index block. 2174 */ 2175 static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode, 2176 struct ext4_ext_path *path) 2177 { 2178 int err; 2179 ext4_fsblk_t leaf; 2180 2181 /* free index block */ 2182 path--; 2183 leaf = ext4_idx_pblock(path->p_idx); 2184 if (unlikely(path->p_hdr->eh_entries == 0)) { 2185 EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0"); 2186 return -EIO; 2187 } 2188 err = ext4_ext_get_access(handle, inode, path); 2189 if (err) 2190 return err; 2191 2192 if (path->p_idx != EXT_LAST_INDEX(path->p_hdr)) { 2193 int len = EXT_LAST_INDEX(path->p_hdr) - path->p_idx; 2194 len *= sizeof(struct ext4_extent_idx); 2195 memmove(path->p_idx, path->p_idx + 1, len); 2196 } 2197 2198 le16_add_cpu(&path->p_hdr->eh_entries, -1); 2199 err = ext4_ext_dirty(handle, inode, path); 2200 if (err) 2201 return err; 2202 ext_debug("index is empty, remove it, free block %llu\n", leaf); 2203 trace_ext4_ext_rm_idx(inode, leaf); 2204 2205 ext4_free_blocks(handle, inode, NULL, leaf, 1, 2206 EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET); 2207 return err; 2208 } 2209 2210 /* 2211 * ext4_ext_calc_credits_for_single_extent: 2212 * This routine returns max. credits that needed to insert an extent 2213 * to the extent tree. 2214 * When pass the actual path, the caller should calculate credits 2215 * under i_data_sem. 2216 */ 2217 int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks, 2218 struct ext4_ext_path *path) 2219 { 2220 if (path) { 2221 int depth = ext_depth(inode); 2222 int ret = 0; 2223 2224 /* probably there is space in leaf? */ 2225 if (le16_to_cpu(path[depth].p_hdr->eh_entries) 2226 < le16_to_cpu(path[depth].p_hdr->eh_max)) { 2227 2228 /* 2229 * There are some space in the leaf tree, no 2230 * need to account for leaf block credit 2231 * 2232 * bitmaps and block group descriptor blocks 2233 * and other metadata blocks still need to be 2234 * accounted. 2235 */ 2236 /* 1 bitmap, 1 block group descriptor */ 2237 ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb); 2238 return ret; 2239 } 2240 } 2241 2242 return ext4_chunk_trans_blocks(inode, nrblocks); 2243 } 2244 2245 /* 2246 * How many index/leaf blocks need to change/allocate to modify nrblocks? 2247 * 2248 * if nrblocks are fit in a single extent (chunk flag is 1), then 2249 * in the worse case, each tree level index/leaf need to be changed 2250 * if the tree split due to insert a new extent, then the old tree 2251 * index/leaf need to be updated too 2252 * 2253 * If the nrblocks are discontiguous, they could cause 2254 * the whole tree split more than once, but this is really rare. 2255 */ 2256 int ext4_ext_index_trans_blocks(struct inode *inode, int nrblocks, int chunk) 2257 { 2258 int index; 2259 int depth = ext_depth(inode); 2260 2261 if (chunk) 2262 index = depth * 2; 2263 else 2264 index = depth * 3; 2265 2266 return index; 2267 } 2268 2269 static int ext4_remove_blocks(handle_t *handle, struct inode *inode, 2270 struct ext4_extent *ex, 2271 ext4_fsblk_t *partial_cluster, 2272 ext4_lblk_t from, ext4_lblk_t to) 2273 { 2274 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 2275 unsigned short ee_len = ext4_ext_get_actual_len(ex); 2276 ext4_fsblk_t pblk; 2277 int flags = EXT4_FREE_BLOCKS_FORGET; 2278 2279 if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) 2280 flags |= EXT4_FREE_BLOCKS_METADATA; 2281 /* 2282 * For bigalloc file systems, we never free a partial cluster 2283 * at the beginning of the extent. Instead, we make a note 2284 * that we tried freeing the cluster, and check to see if we 2285 * need to free it on a subsequent call to ext4_remove_blocks, 2286 * or at the end of the ext4_truncate() operation. 2287 */ 2288 flags |= EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER; 2289 2290 trace_ext4_remove_blocks(inode, ex, from, to, *partial_cluster); 2291 /* 2292 * If we have a partial cluster, and it's different from the 2293 * cluster of the last block, we need to explicitly free the 2294 * partial cluster here. 2295 */ 2296 pblk = ext4_ext_pblock(ex) + ee_len - 1; 2297 if (*partial_cluster && (EXT4_B2C(sbi, pblk) != *partial_cluster)) { 2298 ext4_free_blocks(handle, inode, NULL, 2299 EXT4_C2B(sbi, *partial_cluster), 2300 sbi->s_cluster_ratio, flags); 2301 *partial_cluster = 0; 2302 } 2303 2304 #ifdef EXTENTS_STATS 2305 { 2306 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 2307 spin_lock(&sbi->s_ext_stats_lock); 2308 sbi->s_ext_blocks += ee_len; 2309 sbi->s_ext_extents++; 2310 if (ee_len < sbi->s_ext_min) 2311 sbi->s_ext_min = ee_len; 2312 if (ee_len > sbi->s_ext_max) 2313 sbi->s_ext_max = ee_len; 2314 if (ext_depth(inode) > sbi->s_depth_max) 2315 sbi->s_depth_max = ext_depth(inode); 2316 spin_unlock(&sbi->s_ext_stats_lock); 2317 } 2318 #endif 2319 if (from >= le32_to_cpu(ex->ee_block) 2320 && to == le32_to_cpu(ex->ee_block) + ee_len - 1) { 2321 /* tail removal */ 2322 ext4_lblk_t num; 2323 2324 num = le32_to_cpu(ex->ee_block) + ee_len - from; 2325 pblk = ext4_ext_pblock(ex) + ee_len - num; 2326 ext_debug("free last %u blocks starting %llu\n", num, pblk); 2327 ext4_free_blocks(handle, inode, NULL, pblk, num, flags); 2328 /* 2329 * If the block range to be freed didn't start at the 2330 * beginning of a cluster, and we removed the entire 2331 * extent, save the partial cluster here, since we 2332 * might need to delete if we determine that the 2333 * truncate operation has removed all of the blocks in 2334 * the cluster. 2335 */ 2336 if (pblk & (sbi->s_cluster_ratio - 1) && 2337 (ee_len == num)) 2338 *partial_cluster = EXT4_B2C(sbi, pblk); 2339 else 2340 *partial_cluster = 0; 2341 } else if (from == le32_to_cpu(ex->ee_block) 2342 && to <= le32_to_cpu(ex->ee_block) + ee_len - 1) { 2343 /* head removal */ 2344 ext4_lblk_t num; 2345 ext4_fsblk_t start; 2346 2347 num = to - from; 2348 start = ext4_ext_pblock(ex); 2349 2350 ext_debug("free first %u blocks starting %llu\n", num, start); 2351 ext4_free_blocks(handle, inode, NULL, start, num, flags); 2352 2353 } else { 2354 printk(KERN_INFO "strange request: removal(2) " 2355 "%u-%u from %u:%u\n", 2356 from, to, le32_to_cpu(ex->ee_block), ee_len); 2357 } 2358 return 0; 2359 } 2360 2361 2362 /* 2363 * ext4_ext_rm_leaf() Removes the extents associated with the 2364 * blocks appearing between "start" and "end", and splits the extents 2365 * if "start" and "end" appear in the same extent 2366 * 2367 * @handle: The journal handle 2368 * @inode: The files inode 2369 * @path: The path to the leaf 2370 * @start: The first block to remove 2371 * @end: The last block to remove 2372 */ 2373 static int 2374 ext4_ext_rm_leaf(handle_t *handle, struct inode *inode, 2375 struct ext4_ext_path *path, ext4_fsblk_t *partial_cluster, 2376 ext4_lblk_t start, ext4_lblk_t end) 2377 { 2378 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 2379 int err = 0, correct_index = 0; 2380 int depth = ext_depth(inode), credits; 2381 struct ext4_extent_header *eh; 2382 ext4_lblk_t a, b; 2383 unsigned num; 2384 ext4_lblk_t ex_ee_block; 2385 unsigned short ex_ee_len; 2386 unsigned uninitialized = 0; 2387 struct ext4_extent *ex; 2388 2389 /* the header must be checked already in ext4_ext_remove_space() */ 2390 ext_debug("truncate since %u in leaf to %u\n", start, end); 2391 if (!path[depth].p_hdr) 2392 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh); 2393 eh = path[depth].p_hdr; 2394 if (unlikely(path[depth].p_hdr == NULL)) { 2395 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth); 2396 return -EIO; 2397 } 2398 /* find where to start removing */ 2399 ex = EXT_LAST_EXTENT(eh); 2400 2401 ex_ee_block = le32_to_cpu(ex->ee_block); 2402 ex_ee_len = ext4_ext_get_actual_len(ex); 2403 2404 trace_ext4_ext_rm_leaf(inode, start, ex, *partial_cluster); 2405 2406 while (ex >= EXT_FIRST_EXTENT(eh) && 2407 ex_ee_block + ex_ee_len > start) { 2408 2409 if (ext4_ext_is_uninitialized(ex)) 2410 uninitialized = 1; 2411 else 2412 uninitialized = 0; 2413 2414 ext_debug("remove ext %u:[%d]%d\n", ex_ee_block, 2415 uninitialized, ex_ee_len); 2416 path[depth].p_ext = ex; 2417 2418 a = ex_ee_block > start ? ex_ee_block : start; 2419 b = ex_ee_block+ex_ee_len - 1 < end ? 2420 ex_ee_block+ex_ee_len - 1 : end; 2421 2422 ext_debug(" border %u:%u\n", a, b); 2423 2424 /* If this extent is beyond the end of the hole, skip it */ 2425 if (end < ex_ee_block) { 2426 ex--; 2427 ex_ee_block = le32_to_cpu(ex->ee_block); 2428 ex_ee_len = ext4_ext_get_actual_len(ex); 2429 continue; 2430 } else if (b != ex_ee_block + ex_ee_len - 1) { 2431 EXT4_ERROR_INODE(inode, 2432 "can not handle truncate %u:%u " 2433 "on extent %u:%u", 2434 start, end, ex_ee_block, 2435 ex_ee_block + ex_ee_len - 1); 2436 err = -EIO; 2437 goto out; 2438 } else if (a != ex_ee_block) { 2439 /* remove tail of the extent */ 2440 num = a - ex_ee_block; 2441 } else { 2442 /* remove whole extent: excellent! */ 2443 num = 0; 2444 } 2445 /* 2446 * 3 for leaf, sb, and inode plus 2 (bmap and group 2447 * descriptor) for each block group; assume two block 2448 * groups plus ex_ee_len/blocks_per_block_group for 2449 * the worst case 2450 */ 2451 credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb)); 2452 if (ex == EXT_FIRST_EXTENT(eh)) { 2453 correct_index = 1; 2454 credits += (ext_depth(inode)) + 1; 2455 } 2456 credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb); 2457 2458 err = ext4_ext_truncate_extend_restart(handle, inode, credits); 2459 if (err) 2460 goto out; 2461 2462 err = ext4_ext_get_access(handle, inode, path + depth); 2463 if (err) 2464 goto out; 2465 2466 err = ext4_remove_blocks(handle, inode, ex, partial_cluster, 2467 a, b); 2468 if (err) 2469 goto out; 2470 2471 if (num == 0) 2472 /* this extent is removed; mark slot entirely unused */ 2473 ext4_ext_store_pblock(ex, 0); 2474 2475 ex->ee_len = cpu_to_le16(num); 2476 /* 2477 * Do not mark uninitialized if all the blocks in the 2478 * extent have been removed. 2479 */ 2480 if (uninitialized && num) 2481 ext4_ext_mark_uninitialized(ex); 2482 /* 2483 * If the extent was completely released, 2484 * we need to remove it from the leaf 2485 */ 2486 if (num == 0) { 2487 if (end != EXT_MAX_BLOCKS - 1) { 2488 /* 2489 * For hole punching, we need to scoot all the 2490 * extents up when an extent is removed so that 2491 * we dont have blank extents in the middle 2492 */ 2493 memmove(ex, ex+1, (EXT_LAST_EXTENT(eh) - ex) * 2494 sizeof(struct ext4_extent)); 2495 2496 /* Now get rid of the one at the end */ 2497 memset(EXT_LAST_EXTENT(eh), 0, 2498 sizeof(struct ext4_extent)); 2499 } 2500 le16_add_cpu(&eh->eh_entries, -1); 2501 } else 2502 *partial_cluster = 0; 2503 2504 err = ext4_ext_dirty(handle, inode, path + depth); 2505 if (err) 2506 goto out; 2507 2508 ext_debug("new extent: %u:%u:%llu\n", ex_ee_block, num, 2509 ext4_ext_pblock(ex)); 2510 ex--; 2511 ex_ee_block = le32_to_cpu(ex->ee_block); 2512 ex_ee_len = ext4_ext_get_actual_len(ex); 2513 } 2514 2515 if (correct_index && eh->eh_entries) 2516 err = ext4_ext_correct_indexes(handle, inode, path); 2517 2518 /* 2519 * If there is still a entry in the leaf node, check to see if 2520 * it references the partial cluster. This is the only place 2521 * where it could; if it doesn't, we can free the cluster. 2522 */ 2523 if (*partial_cluster && ex >= EXT_FIRST_EXTENT(eh) && 2524 (EXT4_B2C(sbi, ext4_ext_pblock(ex) + ex_ee_len - 1) != 2525 *partial_cluster)) { 2526 int flags = EXT4_FREE_BLOCKS_FORGET; 2527 2528 if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) 2529 flags |= EXT4_FREE_BLOCKS_METADATA; 2530 2531 ext4_free_blocks(handle, inode, NULL, 2532 EXT4_C2B(sbi, *partial_cluster), 2533 sbi->s_cluster_ratio, flags); 2534 *partial_cluster = 0; 2535 } 2536 2537 /* if this leaf is free, then we should 2538 * remove it from index block above */ 2539 if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL) 2540 err = ext4_ext_rm_idx(handle, inode, path + depth); 2541 2542 out: 2543 return err; 2544 } 2545 2546 /* 2547 * ext4_ext_more_to_rm: 2548 * returns 1 if current index has to be freed (even partial) 2549 */ 2550 static int 2551 ext4_ext_more_to_rm(struct ext4_ext_path *path) 2552 { 2553 BUG_ON(path->p_idx == NULL); 2554 2555 if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr)) 2556 return 0; 2557 2558 /* 2559 * if truncate on deeper level happened, it wasn't partial, 2560 * so we have to consider current index for truncation 2561 */ 2562 if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block) 2563 return 0; 2564 return 1; 2565 } 2566 2567 static int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start, 2568 ext4_lblk_t end) 2569 { 2570 struct super_block *sb = inode->i_sb; 2571 int depth = ext_depth(inode); 2572 struct ext4_ext_path *path = NULL; 2573 ext4_fsblk_t partial_cluster = 0; 2574 handle_t *handle; 2575 int i = 0, err; 2576 2577 ext_debug("truncate since %u to %u\n", start, end); 2578 2579 /* probably first extent we're gonna free will be last in block */ 2580 handle = ext4_journal_start(inode, depth + 1); 2581 if (IS_ERR(handle)) 2582 return PTR_ERR(handle); 2583 2584 again: 2585 ext4_ext_invalidate_cache(inode); 2586 2587 trace_ext4_ext_remove_space(inode, start, depth); 2588 2589 /* 2590 * Check if we are removing extents inside the extent tree. If that 2591 * is the case, we are going to punch a hole inside the extent tree 2592 * so we have to check whether we need to split the extent covering 2593 * the last block to remove so we can easily remove the part of it 2594 * in ext4_ext_rm_leaf(). 2595 */ 2596 if (end < EXT_MAX_BLOCKS - 1) { 2597 struct ext4_extent *ex; 2598 ext4_lblk_t ee_block; 2599 2600 /* find extent for this block */ 2601 path = ext4_ext_find_extent(inode, end, NULL); 2602 if (IS_ERR(path)) { 2603 ext4_journal_stop(handle); 2604 return PTR_ERR(path); 2605 } 2606 depth = ext_depth(inode); 2607 ex = path[depth].p_ext; 2608 if (!ex) { 2609 ext4_ext_drop_refs(path); 2610 kfree(path); 2611 path = NULL; 2612 goto cont; 2613 } 2614 2615 ee_block = le32_to_cpu(ex->ee_block); 2616 2617 /* 2618 * See if the last block is inside the extent, if so split 2619 * the extent at 'end' block so we can easily remove the 2620 * tail of the first part of the split extent in 2621 * ext4_ext_rm_leaf(). 2622 */ 2623 if (end >= ee_block && 2624 end < ee_block + ext4_ext_get_actual_len(ex) - 1) { 2625 int split_flag = 0; 2626 2627 if (ext4_ext_is_uninitialized(ex)) 2628 split_flag = EXT4_EXT_MARK_UNINIT1 | 2629 EXT4_EXT_MARK_UNINIT2; 2630 2631 /* 2632 * Split the extent in two so that 'end' is the last 2633 * block in the first new extent 2634 */ 2635 err = ext4_split_extent_at(handle, inode, path, 2636 end + 1, split_flag, 2637 EXT4_GET_BLOCKS_PRE_IO | 2638 EXT4_GET_BLOCKS_PUNCH_OUT_EXT); 2639 2640 if (err < 0) 2641 goto out; 2642 } 2643 } 2644 cont: 2645 2646 /* 2647 * We start scanning from right side, freeing all the blocks 2648 * after i_size and walking into the tree depth-wise. 2649 */ 2650 depth = ext_depth(inode); 2651 if (path) { 2652 int k = i = depth; 2653 while (--k > 0) 2654 path[k].p_block = 2655 le16_to_cpu(path[k].p_hdr->eh_entries)+1; 2656 } else { 2657 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1), 2658 GFP_NOFS); 2659 if (path == NULL) { 2660 ext4_journal_stop(handle); 2661 return -ENOMEM; 2662 } 2663 path[0].p_depth = depth; 2664 path[0].p_hdr = ext_inode_hdr(inode); 2665 i = 0; 2666 2667 if (ext4_ext_check(inode, path[0].p_hdr, depth)) { 2668 err = -EIO; 2669 goto out; 2670 } 2671 } 2672 err = 0; 2673 2674 while (i >= 0 && err == 0) { 2675 if (i == depth) { 2676 /* this is leaf block */ 2677 err = ext4_ext_rm_leaf(handle, inode, path, 2678 &partial_cluster, start, 2679 end); 2680 /* root level has p_bh == NULL, brelse() eats this */ 2681 brelse(path[i].p_bh); 2682 path[i].p_bh = NULL; 2683 i--; 2684 continue; 2685 } 2686 2687 /* this is index block */ 2688 if (!path[i].p_hdr) { 2689 ext_debug("initialize header\n"); 2690 path[i].p_hdr = ext_block_hdr(path[i].p_bh); 2691 } 2692 2693 if (!path[i].p_idx) { 2694 /* this level hasn't been touched yet */ 2695 path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr); 2696 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1; 2697 ext_debug("init index ptr: hdr 0x%p, num %d\n", 2698 path[i].p_hdr, 2699 le16_to_cpu(path[i].p_hdr->eh_entries)); 2700 } else { 2701 /* we were already here, see at next index */ 2702 path[i].p_idx--; 2703 } 2704 2705 ext_debug("level %d - index, first 0x%p, cur 0x%p\n", 2706 i, EXT_FIRST_INDEX(path[i].p_hdr), 2707 path[i].p_idx); 2708 if (ext4_ext_more_to_rm(path + i)) { 2709 struct buffer_head *bh; 2710 /* go to the next level */ 2711 ext_debug("move to level %d (block %llu)\n", 2712 i + 1, ext4_idx_pblock(path[i].p_idx)); 2713 memset(path + i + 1, 0, sizeof(*path)); 2714 bh = sb_bread(sb, ext4_idx_pblock(path[i].p_idx)); 2715 if (!bh) { 2716 /* should we reset i_size? */ 2717 err = -EIO; 2718 break; 2719 } 2720 if (WARN_ON(i + 1 > depth)) { 2721 err = -EIO; 2722 break; 2723 } 2724 if (ext4_ext_check_block(inode, ext_block_hdr(bh), 2725 depth - i - 1, bh)) { 2726 err = -EIO; 2727 break; 2728 } 2729 path[i + 1].p_bh = bh; 2730 2731 /* save actual number of indexes since this 2732 * number is changed at the next iteration */ 2733 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries); 2734 i++; 2735 } else { 2736 /* we finished processing this index, go up */ 2737 if (path[i].p_hdr->eh_entries == 0 && i > 0) { 2738 /* index is empty, remove it; 2739 * handle must be already prepared by the 2740 * truncatei_leaf() */ 2741 err = ext4_ext_rm_idx(handle, inode, path + i); 2742 } 2743 /* root level has p_bh == NULL, brelse() eats this */ 2744 brelse(path[i].p_bh); 2745 path[i].p_bh = NULL; 2746 i--; 2747 ext_debug("return to level %d\n", i); 2748 } 2749 } 2750 2751 trace_ext4_ext_remove_space_done(inode, start, depth, partial_cluster, 2752 path->p_hdr->eh_entries); 2753 2754 /* If we still have something in the partial cluster and we have removed 2755 * even the first extent, then we should free the blocks in the partial 2756 * cluster as well. */ 2757 if (partial_cluster && path->p_hdr->eh_entries == 0) { 2758 int flags = EXT4_FREE_BLOCKS_FORGET; 2759 2760 if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) 2761 flags |= EXT4_FREE_BLOCKS_METADATA; 2762 2763 ext4_free_blocks(handle, inode, NULL, 2764 EXT4_C2B(EXT4_SB(sb), partial_cluster), 2765 EXT4_SB(sb)->s_cluster_ratio, flags); 2766 partial_cluster = 0; 2767 } 2768 2769 /* TODO: flexible tree reduction should be here */ 2770 if (path->p_hdr->eh_entries == 0) { 2771 /* 2772 * truncate to zero freed all the tree, 2773 * so we need to correct eh_depth 2774 */ 2775 err = ext4_ext_get_access(handle, inode, path); 2776 if (err == 0) { 2777 ext_inode_hdr(inode)->eh_depth = 0; 2778 ext_inode_hdr(inode)->eh_max = 2779 cpu_to_le16(ext4_ext_space_root(inode, 0)); 2780 err = ext4_ext_dirty(handle, inode, path); 2781 } 2782 } 2783 out: 2784 ext4_ext_drop_refs(path); 2785 kfree(path); 2786 if (err == -EAGAIN) { 2787 path = NULL; 2788 goto again; 2789 } 2790 ext4_journal_stop(handle); 2791 2792 return err; 2793 } 2794 2795 /* 2796 * called at mount time 2797 */ 2798 void ext4_ext_init(struct super_block *sb) 2799 { 2800 /* 2801 * possible initialization would be here 2802 */ 2803 2804 if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) { 2805 #if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS) 2806 printk(KERN_INFO "EXT4-fs: file extents enabled" 2807 #ifdef AGGRESSIVE_TEST 2808 ", aggressive tests" 2809 #endif 2810 #ifdef CHECK_BINSEARCH 2811 ", check binsearch" 2812 #endif 2813 #ifdef EXTENTS_STATS 2814 ", stats" 2815 #endif 2816 "\n"); 2817 #endif 2818 #ifdef EXTENTS_STATS 2819 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock); 2820 EXT4_SB(sb)->s_ext_min = 1 << 30; 2821 EXT4_SB(sb)->s_ext_max = 0; 2822 #endif 2823 } 2824 } 2825 2826 /* 2827 * called at umount time 2828 */ 2829 void ext4_ext_release(struct super_block *sb) 2830 { 2831 if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) 2832 return; 2833 2834 #ifdef EXTENTS_STATS 2835 if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) { 2836 struct ext4_sb_info *sbi = EXT4_SB(sb); 2837 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n", 2838 sbi->s_ext_blocks, sbi->s_ext_extents, 2839 sbi->s_ext_blocks / sbi->s_ext_extents); 2840 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n", 2841 sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max); 2842 } 2843 #endif 2844 } 2845 2846 /* FIXME!! we need to try to merge to left or right after zero-out */ 2847 static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex) 2848 { 2849 ext4_fsblk_t ee_pblock; 2850 unsigned int ee_len; 2851 int ret; 2852 2853 ee_len = ext4_ext_get_actual_len(ex); 2854 ee_pblock = ext4_ext_pblock(ex); 2855 2856 ret = sb_issue_zeroout(inode->i_sb, ee_pblock, ee_len, GFP_NOFS); 2857 if (ret > 0) 2858 ret = 0; 2859 2860 return ret; 2861 } 2862 2863 /* 2864 * ext4_split_extent_at() splits an extent at given block. 2865 * 2866 * @handle: the journal handle 2867 * @inode: the file inode 2868 * @path: the path to the extent 2869 * @split: the logical block where the extent is splitted. 2870 * @split_flags: indicates if the extent could be zeroout if split fails, and 2871 * the states(init or uninit) of new extents. 2872 * @flags: flags used to insert new extent to extent tree. 2873 * 2874 * 2875 * Splits extent [a, b] into two extents [a, @split) and [@split, b], states 2876 * of which are deterimined by split_flag. 2877 * 2878 * There are two cases: 2879 * a> the extent are splitted into two extent. 2880 * b> split is not needed, and just mark the extent. 2881 * 2882 * return 0 on success. 2883 */ 2884 static int ext4_split_extent_at(handle_t *handle, 2885 struct inode *inode, 2886 struct ext4_ext_path *path, 2887 ext4_lblk_t split, 2888 int split_flag, 2889 int flags) 2890 { 2891 ext4_fsblk_t newblock; 2892 ext4_lblk_t ee_block; 2893 struct ext4_extent *ex, newex, orig_ex; 2894 struct ext4_extent *ex2 = NULL; 2895 unsigned int ee_len, depth; 2896 int err = 0; 2897 2898 ext_debug("ext4_split_extents_at: inode %lu, logical" 2899 "block %llu\n", inode->i_ino, (unsigned long long)split); 2900 2901 ext4_ext_show_leaf(inode, path); 2902 2903 depth = ext_depth(inode); 2904 ex = path[depth].p_ext; 2905 ee_block = le32_to_cpu(ex->ee_block); 2906 ee_len = ext4_ext_get_actual_len(ex); 2907 newblock = split - ee_block + ext4_ext_pblock(ex); 2908 2909 BUG_ON(split < ee_block || split >= (ee_block + ee_len)); 2910 2911 err = ext4_ext_get_access(handle, inode, path + depth); 2912 if (err) 2913 goto out; 2914 2915 if (split == ee_block) { 2916 /* 2917 * case b: block @split is the block that the extent begins with 2918 * then we just change the state of the extent, and splitting 2919 * is not needed. 2920 */ 2921 if (split_flag & EXT4_EXT_MARK_UNINIT2) 2922 ext4_ext_mark_uninitialized(ex); 2923 else 2924 ext4_ext_mark_initialized(ex); 2925 2926 if (!(flags & EXT4_GET_BLOCKS_PRE_IO)) 2927 ext4_ext_try_to_merge(inode, path, ex); 2928 2929 err = ext4_ext_dirty(handle, inode, path + depth); 2930 goto out; 2931 } 2932 2933 /* case a */ 2934 memcpy(&orig_ex, ex, sizeof(orig_ex)); 2935 ex->ee_len = cpu_to_le16(split - ee_block); 2936 if (split_flag & EXT4_EXT_MARK_UNINIT1) 2937 ext4_ext_mark_uninitialized(ex); 2938 2939 /* 2940 * path may lead to new leaf, not to original leaf any more 2941 * after ext4_ext_insert_extent() returns, 2942 */ 2943 err = ext4_ext_dirty(handle, inode, path + depth); 2944 if (err) 2945 goto fix_extent_len; 2946 2947 ex2 = &newex; 2948 ex2->ee_block = cpu_to_le32(split); 2949 ex2->ee_len = cpu_to_le16(ee_len - (split - ee_block)); 2950 ext4_ext_store_pblock(ex2, newblock); 2951 if (split_flag & EXT4_EXT_MARK_UNINIT2) 2952 ext4_ext_mark_uninitialized(ex2); 2953 2954 err = ext4_ext_insert_extent(handle, inode, path, &newex, flags); 2955 if (err == -ENOSPC && (EXT4_EXT_MAY_ZEROOUT & split_flag)) { 2956 err = ext4_ext_zeroout(inode, &orig_ex); 2957 if (err) 2958 goto fix_extent_len; 2959 /* update the extent length and mark as initialized */ 2960 ex->ee_len = cpu_to_le16(ee_len); 2961 ext4_ext_try_to_merge(inode, path, ex); 2962 err = ext4_ext_dirty(handle, inode, path + depth); 2963 goto out; 2964 } else if (err) 2965 goto fix_extent_len; 2966 2967 out: 2968 ext4_ext_show_leaf(inode, path); 2969 return err; 2970 2971 fix_extent_len: 2972 ex->ee_len = orig_ex.ee_len; 2973 ext4_ext_dirty(handle, inode, path + depth); 2974 return err; 2975 } 2976 2977 /* 2978 * ext4_split_extents() splits an extent and mark extent which is covered 2979 * by @map as split_flags indicates 2980 * 2981 * It may result in splitting the extent into multiple extents (upto three) 2982 * There are three possibilities: 2983 * a> There is no split required 2984 * b> Splits in two extents: Split is happening at either end of the extent 2985 * c> Splits in three extents: Somone is splitting in middle of the extent 2986 * 2987 */ 2988 static int ext4_split_extent(handle_t *handle, 2989 struct inode *inode, 2990 struct ext4_ext_path *path, 2991 struct ext4_map_blocks *map, 2992 int split_flag, 2993 int flags) 2994 { 2995 ext4_lblk_t ee_block; 2996 struct ext4_extent *ex; 2997 unsigned int ee_len, depth; 2998 int err = 0; 2999 int uninitialized; 3000 int split_flag1, flags1; 3001 3002 depth = ext_depth(inode); 3003 ex = path[depth].p_ext; 3004 ee_block = le32_to_cpu(ex->ee_block); 3005 ee_len = ext4_ext_get_actual_len(ex); 3006 uninitialized = ext4_ext_is_uninitialized(ex); 3007 3008 if (map->m_lblk + map->m_len < ee_block + ee_len) { 3009 split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT ? 3010 EXT4_EXT_MAY_ZEROOUT : 0; 3011 flags1 = flags | EXT4_GET_BLOCKS_PRE_IO; 3012 if (uninitialized) 3013 split_flag1 |= EXT4_EXT_MARK_UNINIT1 | 3014 EXT4_EXT_MARK_UNINIT2; 3015 err = ext4_split_extent_at(handle, inode, path, 3016 map->m_lblk + map->m_len, split_flag1, flags1); 3017 if (err) 3018 goto out; 3019 } 3020 3021 ext4_ext_drop_refs(path); 3022 path = ext4_ext_find_extent(inode, map->m_lblk, path); 3023 if (IS_ERR(path)) 3024 return PTR_ERR(path); 3025 3026 if (map->m_lblk >= ee_block) { 3027 split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT ? 3028 EXT4_EXT_MAY_ZEROOUT : 0; 3029 if (uninitialized) 3030 split_flag1 |= EXT4_EXT_MARK_UNINIT1; 3031 if (split_flag & EXT4_EXT_MARK_UNINIT2) 3032 split_flag1 |= EXT4_EXT_MARK_UNINIT2; 3033 err = ext4_split_extent_at(handle, inode, path, 3034 map->m_lblk, split_flag1, flags); 3035 if (err) 3036 goto out; 3037 } 3038 3039 ext4_ext_show_leaf(inode, path); 3040 out: 3041 return err ? err : map->m_len; 3042 } 3043 3044 #define EXT4_EXT_ZERO_LEN 7 3045 /* 3046 * This function is called by ext4_ext_map_blocks() if someone tries to write 3047 * to an uninitialized extent. It may result in splitting the uninitialized 3048 * extent into multiple extents (up to three - one initialized and two 3049 * uninitialized). 3050 * There are three possibilities: 3051 * a> There is no split required: Entire extent should be initialized 3052 * b> Splits in two extents: Write is happening at either end of the extent 3053 * c> Splits in three extents: Somone is writing in middle of the extent 3054 * 3055 * Pre-conditions: 3056 * - The extent pointed to by 'path' is uninitialized. 3057 * - The extent pointed to by 'path' contains a superset 3058 * of the logical span [map->m_lblk, map->m_lblk + map->m_len). 3059 * 3060 * Post-conditions on success: 3061 * - the returned value is the number of blocks beyond map->l_lblk 3062 * that are allocated and initialized. 3063 * It is guaranteed to be >= map->m_len. 3064 */ 3065 static int ext4_ext_convert_to_initialized(handle_t *handle, 3066 struct inode *inode, 3067 struct ext4_map_blocks *map, 3068 struct ext4_ext_path *path) 3069 { 3070 struct ext4_extent_header *eh; 3071 struct ext4_map_blocks split_map; 3072 struct ext4_extent zero_ex; 3073 struct ext4_extent *ex; 3074 ext4_lblk_t ee_block, eof_block; 3075 unsigned int ee_len, depth; 3076 int allocated; 3077 int err = 0; 3078 int split_flag = 0; 3079 3080 ext_debug("ext4_ext_convert_to_initialized: inode %lu, logical" 3081 "block %llu, max_blocks %u\n", inode->i_ino, 3082 (unsigned long long)map->m_lblk, map->m_len); 3083 3084 eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >> 3085 inode->i_sb->s_blocksize_bits; 3086 if (eof_block < map->m_lblk + map->m_len) 3087 eof_block = map->m_lblk + map->m_len; 3088 3089 depth = ext_depth(inode); 3090 eh = path[depth].p_hdr; 3091 ex = path[depth].p_ext; 3092 ee_block = le32_to_cpu(ex->ee_block); 3093 ee_len = ext4_ext_get_actual_len(ex); 3094 allocated = ee_len - (map->m_lblk - ee_block); 3095 3096 trace_ext4_ext_convert_to_initialized_enter(inode, map, ex); 3097 3098 /* Pre-conditions */ 3099 BUG_ON(!ext4_ext_is_uninitialized(ex)); 3100 BUG_ON(!in_range(map->m_lblk, ee_block, ee_len)); 3101 3102 /* 3103 * Attempt to transfer newly initialized blocks from the currently 3104 * uninitialized extent to its left neighbor. This is much cheaper 3105 * than an insertion followed by a merge as those involve costly 3106 * memmove() calls. This is the common case in steady state for 3107 * workloads doing fallocate(FALLOC_FL_KEEP_SIZE) followed by append 3108 * writes. 3109 * 3110 * Limitations of the current logic: 3111 * - L1: we only deal with writes at the start of the extent. 3112 * The approach could be extended to writes at the end 3113 * of the extent but this scenario was deemed less common. 3114 * - L2: we do not deal with writes covering the whole extent. 3115 * This would require removing the extent if the transfer 3116 * is possible. 3117 * - L3: we only attempt to merge with an extent stored in the 3118 * same extent tree node. 3119 */ 3120 if ((map->m_lblk == ee_block) && /*L1*/ 3121 (map->m_len < ee_len) && /*L2*/ 3122 (ex > EXT_FIRST_EXTENT(eh))) { /*L3*/ 3123 struct ext4_extent *prev_ex; 3124 ext4_lblk_t prev_lblk; 3125 ext4_fsblk_t prev_pblk, ee_pblk; 3126 unsigned int prev_len, write_len; 3127 3128 prev_ex = ex - 1; 3129 prev_lblk = le32_to_cpu(prev_ex->ee_block); 3130 prev_len = ext4_ext_get_actual_len(prev_ex); 3131 prev_pblk = ext4_ext_pblock(prev_ex); 3132 ee_pblk = ext4_ext_pblock(ex); 3133 write_len = map->m_len; 3134 3135 /* 3136 * A transfer of blocks from 'ex' to 'prev_ex' is allowed 3137 * upon those conditions: 3138 * - C1: prev_ex is initialized, 3139 * - C2: prev_ex is logically abutting ex, 3140 * - C3: prev_ex is physically abutting ex, 3141 * - C4: prev_ex can receive the additional blocks without 3142 * overflowing the (initialized) length limit. 3143 */ 3144 if ((!ext4_ext_is_uninitialized(prev_ex)) && /*C1*/ 3145 ((prev_lblk + prev_len) == ee_block) && /*C2*/ 3146 ((prev_pblk + prev_len) == ee_pblk) && /*C3*/ 3147 (prev_len < (EXT_INIT_MAX_LEN - write_len))) { /*C4*/ 3148 err = ext4_ext_get_access(handle, inode, path + depth); 3149 if (err) 3150 goto out; 3151 3152 trace_ext4_ext_convert_to_initialized_fastpath(inode, 3153 map, ex, prev_ex); 3154 3155 /* Shift the start of ex by 'write_len' blocks */ 3156 ex->ee_block = cpu_to_le32(ee_block + write_len); 3157 ext4_ext_store_pblock(ex, ee_pblk + write_len); 3158 ex->ee_len = cpu_to_le16(ee_len - write_len); 3159 ext4_ext_mark_uninitialized(ex); /* Restore the flag */ 3160 3161 /* Extend prev_ex by 'write_len' blocks */ 3162 prev_ex->ee_len = cpu_to_le16(prev_len + write_len); 3163 3164 /* Mark the block containing both extents as dirty */ 3165 ext4_ext_dirty(handle, inode, path + depth); 3166 3167 /* Update path to point to the right extent */ 3168 path[depth].p_ext = prev_ex; 3169 3170 /* Result: number of initialized blocks past m_lblk */ 3171 allocated = write_len; 3172 goto out; 3173 } 3174 } 3175 3176 WARN_ON(map->m_lblk < ee_block); 3177 /* 3178 * It is safe to convert extent to initialized via explicit 3179 * zeroout only if extent is fully insde i_size or new_size. 3180 */ 3181 split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0; 3182 3183 /* If extent has less than 2*EXT4_EXT_ZERO_LEN zerout directly */ 3184 if (ee_len <= 2*EXT4_EXT_ZERO_LEN && 3185 (EXT4_EXT_MAY_ZEROOUT & split_flag)) { 3186 err = ext4_ext_zeroout(inode, ex); 3187 if (err) 3188 goto out; 3189 3190 err = ext4_ext_get_access(handle, inode, path + depth); 3191 if (err) 3192 goto out; 3193 ext4_ext_mark_initialized(ex); 3194 ext4_ext_try_to_merge(inode, path, ex); 3195 err = ext4_ext_dirty(handle, inode, path + depth); 3196 goto out; 3197 } 3198 3199 /* 3200 * four cases: 3201 * 1. split the extent into three extents. 3202 * 2. split the extent into two extents, zeroout the first half. 3203 * 3. split the extent into two extents, zeroout the second half. 3204 * 4. split the extent into two extents with out zeroout. 3205 */ 3206 split_map.m_lblk = map->m_lblk; 3207 split_map.m_len = map->m_len; 3208 3209 if (allocated > map->m_len) { 3210 if (allocated <= EXT4_EXT_ZERO_LEN && 3211 (EXT4_EXT_MAY_ZEROOUT & split_flag)) { 3212 /* case 3 */ 3213 zero_ex.ee_block = 3214 cpu_to_le32(map->m_lblk); 3215 zero_ex.ee_len = cpu_to_le16(allocated); 3216 ext4_ext_store_pblock(&zero_ex, 3217 ext4_ext_pblock(ex) + map->m_lblk - ee_block); 3218 err = ext4_ext_zeroout(inode, &zero_ex); 3219 if (err) 3220 goto out; 3221 split_map.m_lblk = map->m_lblk; 3222 split_map.m_len = allocated; 3223 } else if ((map->m_lblk - ee_block + map->m_len < 3224 EXT4_EXT_ZERO_LEN) && 3225 (EXT4_EXT_MAY_ZEROOUT & split_flag)) { 3226 /* case 2 */ 3227 if (map->m_lblk != ee_block) { 3228 zero_ex.ee_block = ex->ee_block; 3229 zero_ex.ee_len = cpu_to_le16(map->m_lblk - 3230 ee_block); 3231 ext4_ext_store_pblock(&zero_ex, 3232 ext4_ext_pblock(ex)); 3233 err = ext4_ext_zeroout(inode, &zero_ex); 3234 if (err) 3235 goto out; 3236 } 3237 3238 split_map.m_lblk = ee_block; 3239 split_map.m_len = map->m_lblk - ee_block + map->m_len; 3240 allocated = map->m_len; 3241 } 3242 } 3243 3244 allocated = ext4_split_extent(handle, inode, path, 3245 &split_map, split_flag, 0); 3246 if (allocated < 0) 3247 err = allocated; 3248 3249 out: 3250 return err ? err : allocated; 3251 } 3252 3253 /* 3254 * This function is called by ext4_ext_map_blocks() from 3255 * ext4_get_blocks_dio_write() when DIO to write 3256 * to an uninitialized extent. 3257 * 3258 * Writing to an uninitialized extent may result in splitting the uninitialized 3259 * extent into multiple /initialized uninitialized extents (up to three) 3260 * There are three possibilities: 3261 * a> There is no split required: Entire extent should be uninitialized 3262 * b> Splits in two extents: Write is happening at either end of the extent 3263 * c> Splits in three extents: Somone is writing in middle of the extent 3264 * 3265 * One of more index blocks maybe needed if the extent tree grow after 3266 * the uninitialized extent split. To prevent ENOSPC occur at the IO 3267 * complete, we need to split the uninitialized extent before DIO submit 3268 * the IO. The uninitialized extent called at this time will be split 3269 * into three uninitialized extent(at most). After IO complete, the part 3270 * being filled will be convert to initialized by the end_io callback function 3271 * via ext4_convert_unwritten_extents(). 3272 * 3273 * Returns the size of uninitialized extent to be written on success. 3274 */ 3275 static int ext4_split_unwritten_extents(handle_t *handle, 3276 struct inode *inode, 3277 struct ext4_map_blocks *map, 3278 struct ext4_ext_path *path, 3279 int flags) 3280 { 3281 ext4_lblk_t eof_block; 3282 ext4_lblk_t ee_block; 3283 struct ext4_extent *ex; 3284 unsigned int ee_len; 3285 int split_flag = 0, depth; 3286 3287 ext_debug("ext4_split_unwritten_extents: inode %lu, logical" 3288 "block %llu, max_blocks %u\n", inode->i_ino, 3289 (unsigned long long)map->m_lblk, map->m_len); 3290 3291 eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >> 3292 inode->i_sb->s_blocksize_bits; 3293 if (eof_block < map->m_lblk + map->m_len) 3294 eof_block = map->m_lblk + map->m_len; 3295 /* 3296 * It is safe to convert extent to initialized via explicit 3297 * zeroout only if extent is fully insde i_size or new_size. 3298 */ 3299 depth = ext_depth(inode); 3300 ex = path[depth].p_ext; 3301 ee_block = le32_to_cpu(ex->ee_block); 3302 ee_len = ext4_ext_get_actual_len(ex); 3303 3304 split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0; 3305 split_flag |= EXT4_EXT_MARK_UNINIT2; 3306 3307 flags |= EXT4_GET_BLOCKS_PRE_IO; 3308 return ext4_split_extent(handle, inode, path, map, split_flag, flags); 3309 } 3310 3311 static int ext4_convert_unwritten_extents_endio(handle_t *handle, 3312 struct inode *inode, 3313 struct ext4_ext_path *path) 3314 { 3315 struct ext4_extent *ex; 3316 int depth; 3317 int err = 0; 3318 3319 depth = ext_depth(inode); 3320 ex = path[depth].p_ext; 3321 3322 ext_debug("ext4_convert_unwritten_extents_endio: inode %lu, logical" 3323 "block %llu, max_blocks %u\n", inode->i_ino, 3324 (unsigned long long)le32_to_cpu(ex->ee_block), 3325 ext4_ext_get_actual_len(ex)); 3326 3327 err = ext4_ext_get_access(handle, inode, path + depth); 3328 if (err) 3329 goto out; 3330 /* first mark the extent as initialized */ 3331 ext4_ext_mark_initialized(ex); 3332 3333 /* note: ext4_ext_correct_indexes() isn't needed here because 3334 * borders are not changed 3335 */ 3336 ext4_ext_try_to_merge(inode, path, ex); 3337 3338 /* Mark modified extent as dirty */ 3339 err = ext4_ext_dirty(handle, inode, path + depth); 3340 out: 3341 ext4_ext_show_leaf(inode, path); 3342 return err; 3343 } 3344 3345 static void unmap_underlying_metadata_blocks(struct block_device *bdev, 3346 sector_t block, int count) 3347 { 3348 int i; 3349 for (i = 0; i < count; i++) 3350 unmap_underlying_metadata(bdev, block + i); 3351 } 3352 3353 /* 3354 * Handle EOFBLOCKS_FL flag, clearing it if necessary 3355 */ 3356 static int check_eofblocks_fl(handle_t *handle, struct inode *inode, 3357 ext4_lblk_t lblk, 3358 struct ext4_ext_path *path, 3359 unsigned int len) 3360 { 3361 int i, depth; 3362 struct ext4_extent_header *eh; 3363 struct ext4_extent *last_ex; 3364 3365 if (!ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS)) 3366 return 0; 3367 3368 depth = ext_depth(inode); 3369 eh = path[depth].p_hdr; 3370 3371 /* 3372 * We're going to remove EOFBLOCKS_FL entirely in future so we 3373 * do not care for this case anymore. Simply remove the flag 3374 * if there are no extents. 3375 */ 3376 if (unlikely(!eh->eh_entries)) 3377 goto out; 3378 last_ex = EXT_LAST_EXTENT(eh); 3379 /* 3380 * We should clear the EOFBLOCKS_FL flag if we are writing the 3381 * last block in the last extent in the file. We test this by 3382 * first checking to see if the caller to 3383 * ext4_ext_get_blocks() was interested in the last block (or 3384 * a block beyond the last block) in the current extent. If 3385 * this turns out to be false, we can bail out from this 3386 * function immediately. 3387 */ 3388 if (lblk + len < le32_to_cpu(last_ex->ee_block) + 3389 ext4_ext_get_actual_len(last_ex)) 3390 return 0; 3391 /* 3392 * If the caller does appear to be planning to write at or 3393 * beyond the end of the current extent, we then test to see 3394 * if the current extent is the last extent in the file, by 3395 * checking to make sure it was reached via the rightmost node 3396 * at each level of the tree. 3397 */ 3398 for (i = depth-1; i >= 0; i--) 3399 if (path[i].p_idx != EXT_LAST_INDEX(path[i].p_hdr)) 3400 return 0; 3401 out: 3402 ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS); 3403 return ext4_mark_inode_dirty(handle, inode); 3404 } 3405 3406 /** 3407 * ext4_find_delalloc_range: find delayed allocated block in the given range. 3408 * 3409 * Goes through the buffer heads in the range [lblk_start, lblk_end] and returns 3410 * whether there are any buffers marked for delayed allocation. It returns '1' 3411 * on the first delalloc'ed buffer head found. If no buffer head in the given 3412 * range is marked for delalloc, it returns 0. 3413 * lblk_start should always be <= lblk_end. 3414 * search_hint_reverse is to indicate that searching in reverse from lblk_end to 3415 * lblk_start might be more efficient (i.e., we will likely hit the delalloc'ed 3416 * block sooner). This is useful when blocks are truncated sequentially from 3417 * lblk_start towards lblk_end. 3418 */ 3419 static int ext4_find_delalloc_range(struct inode *inode, 3420 ext4_lblk_t lblk_start, 3421 ext4_lblk_t lblk_end, 3422 int search_hint_reverse) 3423 { 3424 struct address_space *mapping = inode->i_mapping; 3425 struct buffer_head *head, *bh = NULL; 3426 struct page *page; 3427 ext4_lblk_t i, pg_lblk; 3428 pgoff_t index; 3429 3430 if (!test_opt(inode->i_sb, DELALLOC)) 3431 return 0; 3432 3433 /* reverse search wont work if fs block size is less than page size */ 3434 if (inode->i_blkbits < PAGE_CACHE_SHIFT) 3435 search_hint_reverse = 0; 3436 3437 if (search_hint_reverse) 3438 i = lblk_end; 3439 else 3440 i = lblk_start; 3441 3442 index = i >> (PAGE_CACHE_SHIFT - inode->i_blkbits); 3443 3444 while ((i >= lblk_start) && (i <= lblk_end)) { 3445 page = find_get_page(mapping, index); 3446 if (!page) 3447 goto nextpage; 3448 3449 if (!page_has_buffers(page)) 3450 goto nextpage; 3451 3452 head = page_buffers(page); 3453 if (!head) 3454 goto nextpage; 3455 3456 bh = head; 3457 pg_lblk = index << (PAGE_CACHE_SHIFT - 3458 inode->i_blkbits); 3459 do { 3460 if (unlikely(pg_lblk < lblk_start)) { 3461 /* 3462 * This is possible when fs block size is less 3463 * than page size and our cluster starts/ends in 3464 * middle of the page. So we need to skip the 3465 * initial few blocks till we reach the 'lblk' 3466 */ 3467 pg_lblk++; 3468 continue; 3469 } 3470 3471 /* Check if the buffer is delayed allocated and that it 3472 * is not yet mapped. (when da-buffers are mapped during 3473 * their writeout, their da_mapped bit is set.) 3474 */ 3475 if (buffer_delay(bh) && !buffer_da_mapped(bh)) { 3476 page_cache_release(page); 3477 trace_ext4_find_delalloc_range(inode, 3478 lblk_start, lblk_end, 3479 search_hint_reverse, 3480 1, i); 3481 return 1; 3482 } 3483 if (search_hint_reverse) 3484 i--; 3485 else 3486 i++; 3487 } while ((i >= lblk_start) && (i <= lblk_end) && 3488 ((bh = bh->b_this_page) != head)); 3489 nextpage: 3490 if (page) 3491 page_cache_release(page); 3492 /* 3493 * Move to next page. 'i' will be the first lblk in the next 3494 * page. 3495 */ 3496 if (search_hint_reverse) 3497 index--; 3498 else 3499 index++; 3500 i = index << (PAGE_CACHE_SHIFT - inode->i_blkbits); 3501 } 3502 3503 trace_ext4_find_delalloc_range(inode, lblk_start, lblk_end, 3504 search_hint_reverse, 0, 0); 3505 return 0; 3506 } 3507 3508 int ext4_find_delalloc_cluster(struct inode *inode, ext4_lblk_t lblk, 3509 int search_hint_reverse) 3510 { 3511 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 3512 ext4_lblk_t lblk_start, lblk_end; 3513 lblk_start = lblk & (~(sbi->s_cluster_ratio - 1)); 3514 lblk_end = lblk_start + sbi->s_cluster_ratio - 1; 3515 3516 return ext4_find_delalloc_range(inode, lblk_start, lblk_end, 3517 search_hint_reverse); 3518 } 3519 3520 /** 3521 * Determines how many complete clusters (out of those specified by the 'map') 3522 * are under delalloc and were reserved quota for. 3523 * This function is called when we are writing out the blocks that were 3524 * originally written with their allocation delayed, but then the space was 3525 * allocated using fallocate() before the delayed allocation could be resolved. 3526 * The cases to look for are: 3527 * ('=' indicated delayed allocated blocks 3528 * '-' indicates non-delayed allocated blocks) 3529 * (a) partial clusters towards beginning and/or end outside of allocated range 3530 * are not delalloc'ed. 3531 * Ex: 3532 * |----c---=|====c====|====c====|===-c----| 3533 * |++++++ allocated ++++++| 3534 * ==> 4 complete clusters in above example 3535 * 3536 * (b) partial cluster (outside of allocated range) towards either end is 3537 * marked for delayed allocation. In this case, we will exclude that 3538 * cluster. 3539 * Ex: 3540 * |----====c========|========c========| 3541 * |++++++ allocated ++++++| 3542 * ==> 1 complete clusters in above example 3543 * 3544 * Ex: 3545 * |================c================| 3546 * |++++++ allocated ++++++| 3547 * ==> 0 complete clusters in above example 3548 * 3549 * The ext4_da_update_reserve_space will be called only if we 3550 * determine here that there were some "entire" clusters that span 3551 * this 'allocated' range. 3552 * In the non-bigalloc case, this function will just end up returning num_blks 3553 * without ever calling ext4_find_delalloc_range. 3554 */ 3555 static unsigned int 3556 get_reserved_cluster_alloc(struct inode *inode, ext4_lblk_t lblk_start, 3557 unsigned int num_blks) 3558 { 3559 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 3560 ext4_lblk_t alloc_cluster_start, alloc_cluster_end; 3561 ext4_lblk_t lblk_from, lblk_to, c_offset; 3562 unsigned int allocated_clusters = 0; 3563 3564 alloc_cluster_start = EXT4_B2C(sbi, lblk_start); 3565 alloc_cluster_end = EXT4_B2C(sbi, lblk_start + num_blks - 1); 3566 3567 /* max possible clusters for this allocation */ 3568 allocated_clusters = alloc_cluster_end - alloc_cluster_start + 1; 3569 3570 trace_ext4_get_reserved_cluster_alloc(inode, lblk_start, num_blks); 3571 3572 /* Check towards left side */ 3573 c_offset = lblk_start & (sbi->s_cluster_ratio - 1); 3574 if (c_offset) { 3575 lblk_from = lblk_start & (~(sbi->s_cluster_ratio - 1)); 3576 lblk_to = lblk_from + c_offset - 1; 3577 3578 if (ext4_find_delalloc_range(inode, lblk_from, lblk_to, 0)) 3579 allocated_clusters--; 3580 } 3581 3582 /* Now check towards right. */ 3583 c_offset = (lblk_start + num_blks) & (sbi->s_cluster_ratio - 1); 3584 if (allocated_clusters && c_offset) { 3585 lblk_from = lblk_start + num_blks; 3586 lblk_to = lblk_from + (sbi->s_cluster_ratio - c_offset) - 1; 3587 3588 if (ext4_find_delalloc_range(inode, lblk_from, lblk_to, 0)) 3589 allocated_clusters--; 3590 } 3591 3592 return allocated_clusters; 3593 } 3594 3595 static int 3596 ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode, 3597 struct ext4_map_blocks *map, 3598 struct ext4_ext_path *path, int flags, 3599 unsigned int allocated, ext4_fsblk_t newblock) 3600 { 3601 int ret = 0; 3602 int err = 0; 3603 ext4_io_end_t *io = EXT4_I(inode)->cur_aio_dio; 3604 3605 ext_debug("ext4_ext_handle_uninitialized_extents: inode %lu, logical " 3606 "block %llu, max_blocks %u, flags %x, allocated %u\n", 3607 inode->i_ino, (unsigned long long)map->m_lblk, map->m_len, 3608 flags, allocated); 3609 ext4_ext_show_leaf(inode, path); 3610 3611 trace_ext4_ext_handle_uninitialized_extents(inode, map, allocated, 3612 newblock); 3613 3614 /* get_block() before submit the IO, split the extent */ 3615 if ((flags & EXT4_GET_BLOCKS_PRE_IO)) { 3616 ret = ext4_split_unwritten_extents(handle, inode, map, 3617 path, flags); 3618 /* 3619 * Flag the inode(non aio case) or end_io struct (aio case) 3620 * that this IO needs to conversion to written when IO is 3621 * completed 3622 */ 3623 if (io) 3624 ext4_set_io_unwritten_flag(inode, io); 3625 else 3626 ext4_set_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN); 3627 if (ext4_should_dioread_nolock(inode)) 3628 map->m_flags |= EXT4_MAP_UNINIT; 3629 goto out; 3630 } 3631 /* IO end_io complete, convert the filled extent to written */ 3632 if ((flags & EXT4_GET_BLOCKS_CONVERT)) { 3633 ret = ext4_convert_unwritten_extents_endio(handle, inode, 3634 path); 3635 if (ret >= 0) { 3636 ext4_update_inode_fsync_trans(handle, inode, 1); 3637 err = check_eofblocks_fl(handle, inode, map->m_lblk, 3638 path, map->m_len); 3639 } else 3640 err = ret; 3641 goto out2; 3642 } 3643 /* buffered IO case */ 3644 /* 3645 * repeat fallocate creation request 3646 * we already have an unwritten extent 3647 */ 3648 if (flags & EXT4_GET_BLOCKS_UNINIT_EXT) 3649 goto map_out; 3650 3651 /* buffered READ or buffered write_begin() lookup */ 3652 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) { 3653 /* 3654 * We have blocks reserved already. We 3655 * return allocated blocks so that delalloc 3656 * won't do block reservation for us. But 3657 * the buffer head will be unmapped so that 3658 * a read from the block returns 0s. 3659 */ 3660 map->m_flags |= EXT4_MAP_UNWRITTEN; 3661 goto out1; 3662 } 3663 3664 /* buffered write, writepage time, convert*/ 3665 ret = ext4_ext_convert_to_initialized(handle, inode, map, path); 3666 if (ret >= 0) 3667 ext4_update_inode_fsync_trans(handle, inode, 1); 3668 out: 3669 if (ret <= 0) { 3670 err = ret; 3671 goto out2; 3672 } else 3673 allocated = ret; 3674 map->m_flags |= EXT4_MAP_NEW; 3675 /* 3676 * if we allocated more blocks than requested 3677 * we need to make sure we unmap the extra block 3678 * allocated. The actual needed block will get 3679 * unmapped later when we find the buffer_head marked 3680 * new. 3681 */ 3682 if (allocated > map->m_len) { 3683 unmap_underlying_metadata_blocks(inode->i_sb->s_bdev, 3684 newblock + map->m_len, 3685 allocated - map->m_len); 3686 allocated = map->m_len; 3687 } 3688 3689 /* 3690 * If we have done fallocate with the offset that is already 3691 * delayed allocated, we would have block reservation 3692 * and quota reservation done in the delayed write path. 3693 * But fallocate would have already updated quota and block 3694 * count for this offset. So cancel these reservation 3695 */ 3696 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) { 3697 unsigned int reserved_clusters; 3698 reserved_clusters = get_reserved_cluster_alloc(inode, 3699 map->m_lblk, map->m_len); 3700 if (reserved_clusters) 3701 ext4_da_update_reserve_space(inode, 3702 reserved_clusters, 3703 0); 3704 } 3705 3706 map_out: 3707 map->m_flags |= EXT4_MAP_MAPPED; 3708 if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0) { 3709 err = check_eofblocks_fl(handle, inode, map->m_lblk, path, 3710 map->m_len); 3711 if (err < 0) 3712 goto out2; 3713 } 3714 out1: 3715 if (allocated > map->m_len) 3716 allocated = map->m_len; 3717 ext4_ext_show_leaf(inode, path); 3718 map->m_pblk = newblock; 3719 map->m_len = allocated; 3720 out2: 3721 if (path) { 3722 ext4_ext_drop_refs(path); 3723 kfree(path); 3724 } 3725 return err ? err : allocated; 3726 } 3727 3728 /* 3729 * get_implied_cluster_alloc - check to see if the requested 3730 * allocation (in the map structure) overlaps with a cluster already 3731 * allocated in an extent. 3732 * @sb The filesystem superblock structure 3733 * @map The requested lblk->pblk mapping 3734 * @ex The extent structure which might contain an implied 3735 * cluster allocation 3736 * 3737 * This function is called by ext4_ext_map_blocks() after we failed to 3738 * find blocks that were already in the inode's extent tree. Hence, 3739 * we know that the beginning of the requested region cannot overlap 3740 * the extent from the inode's extent tree. There are three cases we 3741 * want to catch. The first is this case: 3742 * 3743 * |--- cluster # N--| 3744 * |--- extent ---| |---- requested region ---| 3745 * |==========| 3746 * 3747 * The second case that we need to test for is this one: 3748 * 3749 * |--------- cluster # N ----------------| 3750 * |--- requested region --| |------- extent ----| 3751 * |=======================| 3752 * 3753 * The third case is when the requested region lies between two extents 3754 * within the same cluster: 3755 * |------------- cluster # N-------------| 3756 * |----- ex -----| |---- ex_right ----| 3757 * |------ requested region ------| 3758 * |================| 3759 * 3760 * In each of the above cases, we need to set the map->m_pblk and 3761 * map->m_len so it corresponds to the return the extent labelled as 3762 * "|====|" from cluster #N, since it is already in use for data in 3763 * cluster EXT4_B2C(sbi, map->m_lblk). We will then return 1 to 3764 * signal to ext4_ext_map_blocks() that map->m_pblk should be treated 3765 * as a new "allocated" block region. Otherwise, we will return 0 and 3766 * ext4_ext_map_blocks() will then allocate one or more new clusters 3767 * by calling ext4_mb_new_blocks(). 3768 */ 3769 static int get_implied_cluster_alloc(struct super_block *sb, 3770 struct ext4_map_blocks *map, 3771 struct ext4_extent *ex, 3772 struct ext4_ext_path *path) 3773 { 3774 struct ext4_sb_info *sbi = EXT4_SB(sb); 3775 ext4_lblk_t c_offset = map->m_lblk & (sbi->s_cluster_ratio-1); 3776 ext4_lblk_t ex_cluster_start, ex_cluster_end; 3777 ext4_lblk_t rr_cluster_start; 3778 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block); 3779 ext4_fsblk_t ee_start = ext4_ext_pblock(ex); 3780 unsigned short ee_len = ext4_ext_get_actual_len(ex); 3781 3782 /* The extent passed in that we are trying to match */ 3783 ex_cluster_start = EXT4_B2C(sbi, ee_block); 3784 ex_cluster_end = EXT4_B2C(sbi, ee_block + ee_len - 1); 3785 3786 /* The requested region passed into ext4_map_blocks() */ 3787 rr_cluster_start = EXT4_B2C(sbi, map->m_lblk); 3788 3789 if ((rr_cluster_start == ex_cluster_end) || 3790 (rr_cluster_start == ex_cluster_start)) { 3791 if (rr_cluster_start == ex_cluster_end) 3792 ee_start += ee_len - 1; 3793 map->m_pblk = (ee_start & ~(sbi->s_cluster_ratio - 1)) + 3794 c_offset; 3795 map->m_len = min(map->m_len, 3796 (unsigned) sbi->s_cluster_ratio - c_offset); 3797 /* 3798 * Check for and handle this case: 3799 * 3800 * |--------- cluster # N-------------| 3801 * |------- extent ----| 3802 * |--- requested region ---| 3803 * |===========| 3804 */ 3805 3806 if (map->m_lblk < ee_block) 3807 map->m_len = min(map->m_len, ee_block - map->m_lblk); 3808 3809 /* 3810 * Check for the case where there is already another allocated 3811 * block to the right of 'ex' but before the end of the cluster. 3812 * 3813 * |------------- cluster # N-------------| 3814 * |----- ex -----| |---- ex_right ----| 3815 * |------ requested region ------| 3816 * |================| 3817 */ 3818 if (map->m_lblk > ee_block) { 3819 ext4_lblk_t next = ext4_ext_next_allocated_block(path); 3820 map->m_len = min(map->m_len, next - map->m_lblk); 3821 } 3822 3823 trace_ext4_get_implied_cluster_alloc_exit(sb, map, 1); 3824 return 1; 3825 } 3826 3827 trace_ext4_get_implied_cluster_alloc_exit(sb, map, 0); 3828 return 0; 3829 } 3830 3831 3832 /* 3833 * Block allocation/map/preallocation routine for extents based files 3834 * 3835 * 3836 * Need to be called with 3837 * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block 3838 * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem) 3839 * 3840 * return > 0, number of of blocks already mapped/allocated 3841 * if create == 0 and these are pre-allocated blocks 3842 * buffer head is unmapped 3843 * otherwise blocks are mapped 3844 * 3845 * return = 0, if plain look up failed (blocks have not been allocated) 3846 * buffer head is unmapped 3847 * 3848 * return < 0, error case. 3849 */ 3850 int ext4_ext_map_blocks(handle_t *handle, struct inode *inode, 3851 struct ext4_map_blocks *map, int flags) 3852 { 3853 struct ext4_ext_path *path = NULL; 3854 struct ext4_extent newex, *ex, *ex2; 3855 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 3856 ext4_fsblk_t newblock = 0; 3857 int free_on_err = 0, err = 0, depth, ret; 3858 unsigned int allocated = 0, offset = 0; 3859 unsigned int allocated_clusters = 0; 3860 struct ext4_allocation_request ar; 3861 ext4_io_end_t *io = EXT4_I(inode)->cur_aio_dio; 3862 ext4_lblk_t cluster_offset; 3863 3864 ext_debug("blocks %u/%u requested for inode %lu\n", 3865 map->m_lblk, map->m_len, inode->i_ino); 3866 trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags); 3867 3868 /* check in cache */ 3869 if (ext4_ext_in_cache(inode, map->m_lblk, &newex)) { 3870 if (!newex.ee_start_lo && !newex.ee_start_hi) { 3871 if ((sbi->s_cluster_ratio > 1) && 3872 ext4_find_delalloc_cluster(inode, map->m_lblk, 0)) 3873 map->m_flags |= EXT4_MAP_FROM_CLUSTER; 3874 3875 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) { 3876 /* 3877 * block isn't allocated yet and 3878 * user doesn't want to allocate it 3879 */ 3880 goto out2; 3881 } 3882 /* we should allocate requested block */ 3883 } else { 3884 /* block is already allocated */ 3885 if (sbi->s_cluster_ratio > 1) 3886 map->m_flags |= EXT4_MAP_FROM_CLUSTER; 3887 newblock = map->m_lblk 3888 - le32_to_cpu(newex.ee_block) 3889 + ext4_ext_pblock(&newex); 3890 /* number of remaining blocks in the extent */ 3891 allocated = ext4_ext_get_actual_len(&newex) - 3892 (map->m_lblk - le32_to_cpu(newex.ee_block)); 3893 goto out; 3894 } 3895 } 3896 3897 /* find extent for this block */ 3898 path = ext4_ext_find_extent(inode, map->m_lblk, NULL); 3899 if (IS_ERR(path)) { 3900 err = PTR_ERR(path); 3901 path = NULL; 3902 goto out2; 3903 } 3904 3905 depth = ext_depth(inode); 3906 3907 /* 3908 * consistent leaf must not be empty; 3909 * this situation is possible, though, _during_ tree modification; 3910 * this is why assert can't be put in ext4_ext_find_extent() 3911 */ 3912 if (unlikely(path[depth].p_ext == NULL && depth != 0)) { 3913 EXT4_ERROR_INODE(inode, "bad extent address " 3914 "lblock: %lu, depth: %d pblock %lld", 3915 (unsigned long) map->m_lblk, depth, 3916 path[depth].p_block); 3917 err = -EIO; 3918 goto out2; 3919 } 3920 3921 ex = path[depth].p_ext; 3922 if (ex) { 3923 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block); 3924 ext4_fsblk_t ee_start = ext4_ext_pblock(ex); 3925 unsigned short ee_len; 3926 3927 /* 3928 * Uninitialized extents are treated as holes, except that 3929 * we split out initialized portions during a write. 3930 */ 3931 ee_len = ext4_ext_get_actual_len(ex); 3932 3933 trace_ext4_ext_show_extent(inode, ee_block, ee_start, ee_len); 3934 3935 /* if found extent covers block, simply return it */ 3936 if (in_range(map->m_lblk, ee_block, ee_len)) { 3937 newblock = map->m_lblk - ee_block + ee_start; 3938 /* number of remaining blocks in the extent */ 3939 allocated = ee_len - (map->m_lblk - ee_block); 3940 ext_debug("%u fit into %u:%d -> %llu\n", map->m_lblk, 3941 ee_block, ee_len, newblock); 3942 3943 /* 3944 * Do not put uninitialized extent 3945 * in the cache 3946 */ 3947 if (!ext4_ext_is_uninitialized(ex)) { 3948 ext4_ext_put_in_cache(inode, ee_block, 3949 ee_len, ee_start); 3950 goto out; 3951 } 3952 ret = ext4_ext_handle_uninitialized_extents( 3953 handle, inode, map, path, flags, 3954 allocated, newblock); 3955 return ret; 3956 } 3957 } 3958 3959 if ((sbi->s_cluster_ratio > 1) && 3960 ext4_find_delalloc_cluster(inode, map->m_lblk, 0)) 3961 map->m_flags |= EXT4_MAP_FROM_CLUSTER; 3962 3963 /* 3964 * requested block isn't allocated yet; 3965 * we couldn't try to create block if create flag is zero 3966 */ 3967 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) { 3968 /* 3969 * put just found gap into cache to speed up 3970 * subsequent requests 3971 */ 3972 ext4_ext_put_gap_in_cache(inode, path, map->m_lblk); 3973 goto out2; 3974 } 3975 3976 /* 3977 * Okay, we need to do block allocation. 3978 */ 3979 map->m_flags &= ~EXT4_MAP_FROM_CLUSTER; 3980 newex.ee_block = cpu_to_le32(map->m_lblk); 3981 cluster_offset = map->m_lblk & (sbi->s_cluster_ratio-1); 3982 3983 /* 3984 * If we are doing bigalloc, check to see if the extent returned 3985 * by ext4_ext_find_extent() implies a cluster we can use. 3986 */ 3987 if (cluster_offset && ex && 3988 get_implied_cluster_alloc(inode->i_sb, map, ex, path)) { 3989 ar.len = allocated = map->m_len; 3990 newblock = map->m_pblk; 3991 map->m_flags |= EXT4_MAP_FROM_CLUSTER; 3992 goto got_allocated_blocks; 3993 } 3994 3995 /* find neighbour allocated blocks */ 3996 ar.lleft = map->m_lblk; 3997 err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft); 3998 if (err) 3999 goto out2; 4000 ar.lright = map->m_lblk; 4001 ex2 = NULL; 4002 err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright, &ex2); 4003 if (err) 4004 goto out2; 4005 4006 /* Check if the extent after searching to the right implies a 4007 * cluster we can use. */ 4008 if ((sbi->s_cluster_ratio > 1) && ex2 && 4009 get_implied_cluster_alloc(inode->i_sb, map, ex2, path)) { 4010 ar.len = allocated = map->m_len; 4011 newblock = map->m_pblk; 4012 map->m_flags |= EXT4_MAP_FROM_CLUSTER; 4013 goto got_allocated_blocks; 4014 } 4015 4016 /* 4017 * See if request is beyond maximum number of blocks we can have in 4018 * a single extent. For an initialized extent this limit is 4019 * EXT_INIT_MAX_LEN and for an uninitialized extent this limit is 4020 * EXT_UNINIT_MAX_LEN. 4021 */ 4022 if (map->m_len > EXT_INIT_MAX_LEN && 4023 !(flags & EXT4_GET_BLOCKS_UNINIT_EXT)) 4024 map->m_len = EXT_INIT_MAX_LEN; 4025 else if (map->m_len > EXT_UNINIT_MAX_LEN && 4026 (flags & EXT4_GET_BLOCKS_UNINIT_EXT)) 4027 map->m_len = EXT_UNINIT_MAX_LEN; 4028 4029 /* Check if we can really insert (m_lblk)::(m_lblk + m_len) extent */ 4030 newex.ee_len = cpu_to_le16(map->m_len); 4031 err = ext4_ext_check_overlap(sbi, inode, &newex, path); 4032 if (err) 4033 allocated = ext4_ext_get_actual_len(&newex); 4034 else 4035 allocated = map->m_len; 4036 4037 /* allocate new block */ 4038 ar.inode = inode; 4039 ar.goal = ext4_ext_find_goal(inode, path, map->m_lblk); 4040 ar.logical = map->m_lblk; 4041 /* 4042 * We calculate the offset from the beginning of the cluster 4043 * for the logical block number, since when we allocate a 4044 * physical cluster, the physical block should start at the 4045 * same offset from the beginning of the cluster. This is 4046 * needed so that future calls to get_implied_cluster_alloc() 4047 * work correctly. 4048 */ 4049 offset = map->m_lblk & (sbi->s_cluster_ratio - 1); 4050 ar.len = EXT4_NUM_B2C(sbi, offset+allocated); 4051 ar.goal -= offset; 4052 ar.logical -= offset; 4053 if (S_ISREG(inode->i_mode)) 4054 ar.flags = EXT4_MB_HINT_DATA; 4055 else 4056 /* disable in-core preallocation for non-regular files */ 4057 ar.flags = 0; 4058 if (flags & EXT4_GET_BLOCKS_NO_NORMALIZE) 4059 ar.flags |= EXT4_MB_HINT_NOPREALLOC; 4060 newblock = ext4_mb_new_blocks(handle, &ar, &err); 4061 if (!newblock) 4062 goto out2; 4063 ext_debug("allocate new block: goal %llu, found %llu/%u\n", 4064 ar.goal, newblock, allocated); 4065 free_on_err = 1; 4066 allocated_clusters = ar.len; 4067 ar.len = EXT4_C2B(sbi, ar.len) - offset; 4068 if (ar.len > allocated) 4069 ar.len = allocated; 4070 4071 got_allocated_blocks: 4072 /* try to insert new extent into found leaf and return */ 4073 ext4_ext_store_pblock(&newex, newblock + offset); 4074 newex.ee_len = cpu_to_le16(ar.len); 4075 /* Mark uninitialized */ 4076 if (flags & EXT4_GET_BLOCKS_UNINIT_EXT){ 4077 ext4_ext_mark_uninitialized(&newex); 4078 /* 4079 * io_end structure was created for every IO write to an 4080 * uninitialized extent. To avoid unnecessary conversion, 4081 * here we flag the IO that really needs the conversion. 4082 * For non asycn direct IO case, flag the inode state 4083 * that we need to perform conversion when IO is done. 4084 */ 4085 if ((flags & EXT4_GET_BLOCKS_PRE_IO)) { 4086 if (io) 4087 ext4_set_io_unwritten_flag(inode, io); 4088 else 4089 ext4_set_inode_state(inode, 4090 EXT4_STATE_DIO_UNWRITTEN); 4091 } 4092 if (ext4_should_dioread_nolock(inode)) 4093 map->m_flags |= EXT4_MAP_UNINIT; 4094 } 4095 4096 err = 0; 4097 if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0) 4098 err = check_eofblocks_fl(handle, inode, map->m_lblk, 4099 path, ar.len); 4100 if (!err) 4101 err = ext4_ext_insert_extent(handle, inode, path, 4102 &newex, flags); 4103 if (err && free_on_err) { 4104 int fb_flags = flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE ? 4105 EXT4_FREE_BLOCKS_NO_QUOT_UPDATE : 0; 4106 /* free data blocks we just allocated */ 4107 /* not a good idea to call discard here directly, 4108 * but otherwise we'd need to call it every free() */ 4109 ext4_discard_preallocations(inode); 4110 ext4_free_blocks(handle, inode, NULL, ext4_ext_pblock(&newex), 4111 ext4_ext_get_actual_len(&newex), fb_flags); 4112 goto out2; 4113 } 4114 4115 /* previous routine could use block we allocated */ 4116 newblock = ext4_ext_pblock(&newex); 4117 allocated = ext4_ext_get_actual_len(&newex); 4118 if (allocated > map->m_len) 4119 allocated = map->m_len; 4120 map->m_flags |= EXT4_MAP_NEW; 4121 4122 /* 4123 * Update reserved blocks/metadata blocks after successful 4124 * block allocation which had been deferred till now. 4125 */ 4126 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) { 4127 unsigned int reserved_clusters; 4128 /* 4129 * Check how many clusters we had reserved this allocated range 4130 */ 4131 reserved_clusters = get_reserved_cluster_alloc(inode, 4132 map->m_lblk, allocated); 4133 if (map->m_flags & EXT4_MAP_FROM_CLUSTER) { 4134 if (reserved_clusters) { 4135 /* 4136 * We have clusters reserved for this range. 4137 * But since we are not doing actual allocation 4138 * and are simply using blocks from previously 4139 * allocated cluster, we should release the 4140 * reservation and not claim quota. 4141 */ 4142 ext4_da_update_reserve_space(inode, 4143 reserved_clusters, 0); 4144 } 4145 } else { 4146 BUG_ON(allocated_clusters < reserved_clusters); 4147 /* We will claim quota for all newly allocated blocks.*/ 4148 ext4_da_update_reserve_space(inode, allocated_clusters, 4149 1); 4150 if (reserved_clusters < allocated_clusters) { 4151 struct ext4_inode_info *ei = EXT4_I(inode); 4152 int reservation = allocated_clusters - 4153 reserved_clusters; 4154 /* 4155 * It seems we claimed few clusters outside of 4156 * the range of this allocation. We should give 4157 * it back to the reservation pool. This can 4158 * happen in the following case: 4159 * 4160 * * Suppose s_cluster_ratio is 4 (i.e., each 4161 * cluster has 4 blocks. Thus, the clusters 4162 * are [0-3],[4-7],[8-11]... 4163 * * First comes delayed allocation write for 4164 * logical blocks 10 & 11. Since there were no 4165 * previous delayed allocated blocks in the 4166 * range [8-11], we would reserve 1 cluster 4167 * for this write. 4168 * * Next comes write for logical blocks 3 to 8. 4169 * In this case, we will reserve 2 clusters 4170 * (for [0-3] and [4-7]; and not for [8-11] as 4171 * that range has a delayed allocated blocks. 4172 * Thus total reserved clusters now becomes 3. 4173 * * Now, during the delayed allocation writeout 4174 * time, we will first write blocks [3-8] and 4175 * allocate 3 clusters for writing these 4176 * blocks. Also, we would claim all these 4177 * three clusters above. 4178 * * Now when we come here to writeout the 4179 * blocks [10-11], we would expect to claim 4180 * the reservation of 1 cluster we had made 4181 * (and we would claim it since there are no 4182 * more delayed allocated blocks in the range 4183 * [8-11]. But our reserved cluster count had 4184 * already gone to 0. 4185 * 4186 * Thus, at the step 4 above when we determine 4187 * that there are still some unwritten delayed 4188 * allocated blocks outside of our current 4189 * block range, we should increment the 4190 * reserved clusters count so that when the 4191 * remaining blocks finally gets written, we 4192 * could claim them. 4193 */ 4194 dquot_reserve_block(inode, 4195 EXT4_C2B(sbi, reservation)); 4196 spin_lock(&ei->i_block_reservation_lock); 4197 ei->i_reserved_data_blocks += reservation; 4198 spin_unlock(&ei->i_block_reservation_lock); 4199 } 4200 } 4201 } 4202 4203 /* 4204 * Cache the extent and update transaction to commit on fdatasync only 4205 * when it is _not_ an uninitialized extent. 4206 */ 4207 if ((flags & EXT4_GET_BLOCKS_UNINIT_EXT) == 0) { 4208 ext4_ext_put_in_cache(inode, map->m_lblk, allocated, newblock); 4209 ext4_update_inode_fsync_trans(handle, inode, 1); 4210 } else 4211 ext4_update_inode_fsync_trans(handle, inode, 0); 4212 out: 4213 if (allocated > map->m_len) 4214 allocated = map->m_len; 4215 ext4_ext_show_leaf(inode, path); 4216 map->m_flags |= EXT4_MAP_MAPPED; 4217 map->m_pblk = newblock; 4218 map->m_len = allocated; 4219 out2: 4220 if (path) { 4221 ext4_ext_drop_refs(path); 4222 kfree(path); 4223 } 4224 4225 trace_ext4_ext_map_blocks_exit(inode, map->m_lblk, 4226 newblock, map->m_len, err ? err : allocated); 4227 4228 return err ? err : allocated; 4229 } 4230 4231 void ext4_ext_truncate(struct inode *inode) 4232 { 4233 struct address_space *mapping = inode->i_mapping; 4234 struct super_block *sb = inode->i_sb; 4235 ext4_lblk_t last_block; 4236 handle_t *handle; 4237 loff_t page_len; 4238 int err = 0; 4239 4240 /* 4241 * finish any pending end_io work so we won't run the risk of 4242 * converting any truncated blocks to initialized later 4243 */ 4244 ext4_flush_completed_IO(inode); 4245 4246 /* 4247 * probably first extent we're gonna free will be last in block 4248 */ 4249 err = ext4_writepage_trans_blocks(inode); 4250 handle = ext4_journal_start(inode, err); 4251 if (IS_ERR(handle)) 4252 return; 4253 4254 if (inode->i_size % PAGE_CACHE_SIZE != 0) { 4255 page_len = PAGE_CACHE_SIZE - 4256 (inode->i_size & (PAGE_CACHE_SIZE - 1)); 4257 4258 err = ext4_discard_partial_page_buffers(handle, 4259 mapping, inode->i_size, page_len, 0); 4260 4261 if (err) 4262 goto out_stop; 4263 } 4264 4265 if (ext4_orphan_add(handle, inode)) 4266 goto out_stop; 4267 4268 down_write(&EXT4_I(inode)->i_data_sem); 4269 ext4_ext_invalidate_cache(inode); 4270 4271 ext4_discard_preallocations(inode); 4272 4273 /* 4274 * TODO: optimization is possible here. 4275 * Probably we need not scan at all, 4276 * because page truncation is enough. 4277 */ 4278 4279 /* we have to know where to truncate from in crash case */ 4280 EXT4_I(inode)->i_disksize = inode->i_size; 4281 ext4_mark_inode_dirty(handle, inode); 4282 4283 last_block = (inode->i_size + sb->s_blocksize - 1) 4284 >> EXT4_BLOCK_SIZE_BITS(sb); 4285 err = ext4_ext_remove_space(inode, last_block, EXT_MAX_BLOCKS - 1); 4286 4287 /* In a multi-transaction truncate, we only make the final 4288 * transaction synchronous. 4289 */ 4290 if (IS_SYNC(inode)) 4291 ext4_handle_sync(handle); 4292 4293 up_write(&EXT4_I(inode)->i_data_sem); 4294 4295 out_stop: 4296 /* 4297 * If this was a simple ftruncate() and the file will remain alive, 4298 * then we need to clear up the orphan record which we created above. 4299 * However, if this was a real unlink then we were called by 4300 * ext4_delete_inode(), and we allow that function to clean up the 4301 * orphan info for us. 4302 */ 4303 if (inode->i_nlink) 4304 ext4_orphan_del(handle, inode); 4305 4306 inode->i_mtime = inode->i_ctime = ext4_current_time(inode); 4307 ext4_mark_inode_dirty(handle, inode); 4308 ext4_journal_stop(handle); 4309 } 4310 4311 static void ext4_falloc_update_inode(struct inode *inode, 4312 int mode, loff_t new_size, int update_ctime) 4313 { 4314 struct timespec now; 4315 4316 if (update_ctime) { 4317 now = current_fs_time(inode->i_sb); 4318 if (!timespec_equal(&inode->i_ctime, &now)) 4319 inode->i_ctime = now; 4320 } 4321 /* 4322 * Update only when preallocation was requested beyond 4323 * the file size. 4324 */ 4325 if (!(mode & FALLOC_FL_KEEP_SIZE)) { 4326 if (new_size > i_size_read(inode)) 4327 i_size_write(inode, new_size); 4328 if (new_size > EXT4_I(inode)->i_disksize) 4329 ext4_update_i_disksize(inode, new_size); 4330 } else { 4331 /* 4332 * Mark that we allocate beyond EOF so the subsequent truncate 4333 * can proceed even if the new size is the same as i_size. 4334 */ 4335 if (new_size > i_size_read(inode)) 4336 ext4_set_inode_flag(inode, EXT4_INODE_EOFBLOCKS); 4337 } 4338 4339 } 4340 4341 /* 4342 * preallocate space for a file. This implements ext4's fallocate file 4343 * operation, which gets called from sys_fallocate system call. 4344 * For block-mapped files, posix_fallocate should fall back to the method 4345 * of writing zeroes to the required new blocks (the same behavior which is 4346 * expected for file systems which do not support fallocate() system call). 4347 */ 4348 long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len) 4349 { 4350 struct inode *inode = file->f_path.dentry->d_inode; 4351 handle_t *handle; 4352 loff_t new_size; 4353 unsigned int max_blocks; 4354 int ret = 0; 4355 int ret2 = 0; 4356 int retries = 0; 4357 int flags; 4358 struct ext4_map_blocks map; 4359 unsigned int credits, blkbits = inode->i_blkbits; 4360 4361 /* 4362 * currently supporting (pre)allocate mode for extent-based 4363 * files _only_ 4364 */ 4365 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) 4366 return -EOPNOTSUPP; 4367 4368 /* Return error if mode is not supported */ 4369 if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE)) 4370 return -EOPNOTSUPP; 4371 4372 if (mode & FALLOC_FL_PUNCH_HOLE) 4373 return ext4_punch_hole(file, offset, len); 4374 4375 trace_ext4_fallocate_enter(inode, offset, len, mode); 4376 map.m_lblk = offset >> blkbits; 4377 /* 4378 * We can't just convert len to max_blocks because 4379 * If blocksize = 4096 offset = 3072 and len = 2048 4380 */ 4381 max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits) 4382 - map.m_lblk; 4383 /* 4384 * credits to insert 1 extent into extent tree 4385 */ 4386 credits = ext4_chunk_trans_blocks(inode, max_blocks); 4387 mutex_lock(&inode->i_mutex); 4388 ret = inode_newsize_ok(inode, (len + offset)); 4389 if (ret) { 4390 mutex_unlock(&inode->i_mutex); 4391 trace_ext4_fallocate_exit(inode, offset, max_blocks, ret); 4392 return ret; 4393 } 4394 flags = EXT4_GET_BLOCKS_CREATE_UNINIT_EXT; 4395 if (mode & FALLOC_FL_KEEP_SIZE) 4396 flags |= EXT4_GET_BLOCKS_KEEP_SIZE; 4397 /* 4398 * Don't normalize the request if it can fit in one extent so 4399 * that it doesn't get unnecessarily split into multiple 4400 * extents. 4401 */ 4402 if (len <= EXT_UNINIT_MAX_LEN << blkbits) 4403 flags |= EXT4_GET_BLOCKS_NO_NORMALIZE; 4404 retry: 4405 while (ret >= 0 && ret < max_blocks) { 4406 map.m_lblk = map.m_lblk + ret; 4407 map.m_len = max_blocks = max_blocks - ret; 4408 handle = ext4_journal_start(inode, credits); 4409 if (IS_ERR(handle)) { 4410 ret = PTR_ERR(handle); 4411 break; 4412 } 4413 ret = ext4_map_blocks(handle, inode, &map, flags); 4414 if (ret <= 0) { 4415 #ifdef EXT4FS_DEBUG 4416 WARN_ON(ret <= 0); 4417 printk(KERN_ERR "%s: ext4_ext_map_blocks " 4418 "returned error inode#%lu, block=%u, " 4419 "max_blocks=%u", __func__, 4420 inode->i_ino, map.m_lblk, max_blocks); 4421 #endif 4422 ext4_mark_inode_dirty(handle, inode); 4423 ret2 = ext4_journal_stop(handle); 4424 break; 4425 } 4426 if ((map.m_lblk + ret) >= (EXT4_BLOCK_ALIGN(offset + len, 4427 blkbits) >> blkbits)) 4428 new_size = offset + len; 4429 else 4430 new_size = ((loff_t) map.m_lblk + ret) << blkbits; 4431 4432 ext4_falloc_update_inode(inode, mode, new_size, 4433 (map.m_flags & EXT4_MAP_NEW)); 4434 ext4_mark_inode_dirty(handle, inode); 4435 if ((file->f_flags & O_SYNC) && ret >= max_blocks) 4436 ext4_handle_sync(handle); 4437 ret2 = ext4_journal_stop(handle); 4438 if (ret2) 4439 break; 4440 } 4441 if (ret == -ENOSPC && 4442 ext4_should_retry_alloc(inode->i_sb, &retries)) { 4443 ret = 0; 4444 goto retry; 4445 } 4446 mutex_unlock(&inode->i_mutex); 4447 trace_ext4_fallocate_exit(inode, offset, max_blocks, 4448 ret > 0 ? ret2 : ret); 4449 return ret > 0 ? ret2 : ret; 4450 } 4451 4452 /* 4453 * This function convert a range of blocks to written extents 4454 * The caller of this function will pass the start offset and the size. 4455 * all unwritten extents within this range will be converted to 4456 * written extents. 4457 * 4458 * This function is called from the direct IO end io call back 4459 * function, to convert the fallocated extents after IO is completed. 4460 * Returns 0 on success. 4461 */ 4462 int ext4_convert_unwritten_extents(struct inode *inode, loff_t offset, 4463 ssize_t len) 4464 { 4465 handle_t *handle; 4466 unsigned int max_blocks; 4467 int ret = 0; 4468 int ret2 = 0; 4469 struct ext4_map_blocks map; 4470 unsigned int credits, blkbits = inode->i_blkbits; 4471 4472 map.m_lblk = offset >> blkbits; 4473 /* 4474 * We can't just convert len to max_blocks because 4475 * If blocksize = 4096 offset = 3072 and len = 2048 4476 */ 4477 max_blocks = ((EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits) - 4478 map.m_lblk); 4479 /* 4480 * credits to insert 1 extent into extent tree 4481 */ 4482 credits = ext4_chunk_trans_blocks(inode, max_blocks); 4483 while (ret >= 0 && ret < max_blocks) { 4484 map.m_lblk += ret; 4485 map.m_len = (max_blocks -= ret); 4486 handle = ext4_journal_start(inode, credits); 4487 if (IS_ERR(handle)) { 4488 ret = PTR_ERR(handle); 4489 break; 4490 } 4491 ret = ext4_map_blocks(handle, inode, &map, 4492 EXT4_GET_BLOCKS_IO_CONVERT_EXT); 4493 if (ret <= 0) { 4494 WARN_ON(ret <= 0); 4495 ext4_msg(inode->i_sb, KERN_ERR, 4496 "%s:%d: inode #%lu: block %u: len %u: " 4497 "ext4_ext_map_blocks returned %d", 4498 __func__, __LINE__, inode->i_ino, map.m_lblk, 4499 map.m_len, ret); 4500 } 4501 ext4_mark_inode_dirty(handle, inode); 4502 ret2 = ext4_journal_stop(handle); 4503 if (ret <= 0 || ret2 ) 4504 break; 4505 } 4506 return ret > 0 ? ret2 : ret; 4507 } 4508 4509 /* 4510 * Callback function called for each extent to gather FIEMAP information. 4511 */ 4512 static int ext4_ext_fiemap_cb(struct inode *inode, ext4_lblk_t next, 4513 struct ext4_ext_cache *newex, struct ext4_extent *ex, 4514 void *data) 4515 { 4516 __u64 logical; 4517 __u64 physical; 4518 __u64 length; 4519 __u32 flags = 0; 4520 int ret = 0; 4521 struct fiemap_extent_info *fieinfo = data; 4522 unsigned char blksize_bits; 4523 4524 blksize_bits = inode->i_sb->s_blocksize_bits; 4525 logical = (__u64)newex->ec_block << blksize_bits; 4526 4527 if (newex->ec_start == 0) { 4528 /* 4529 * No extent in extent-tree contains block @newex->ec_start, 4530 * then the block may stay in 1)a hole or 2)delayed-extent. 4531 * 4532 * Holes or delayed-extents are processed as follows. 4533 * 1. lookup dirty pages with specified range in pagecache. 4534 * If no page is got, then there is no delayed-extent and 4535 * return with EXT_CONTINUE. 4536 * 2. find the 1st mapped buffer, 4537 * 3. check if the mapped buffer is both in the request range 4538 * and a delayed buffer. If not, there is no delayed-extent, 4539 * then return. 4540 * 4. a delayed-extent is found, the extent will be collected. 4541 */ 4542 ext4_lblk_t end = 0; 4543 pgoff_t last_offset; 4544 pgoff_t offset; 4545 pgoff_t index; 4546 pgoff_t start_index = 0; 4547 struct page **pages = NULL; 4548 struct buffer_head *bh = NULL; 4549 struct buffer_head *head = NULL; 4550 unsigned int nr_pages = PAGE_SIZE / sizeof(struct page *); 4551 4552 pages = kmalloc(PAGE_SIZE, GFP_KERNEL); 4553 if (pages == NULL) 4554 return -ENOMEM; 4555 4556 offset = logical >> PAGE_SHIFT; 4557 repeat: 4558 last_offset = offset; 4559 head = NULL; 4560 ret = find_get_pages_tag(inode->i_mapping, &offset, 4561 PAGECACHE_TAG_DIRTY, nr_pages, pages); 4562 4563 if (!(flags & FIEMAP_EXTENT_DELALLOC)) { 4564 /* First time, try to find a mapped buffer. */ 4565 if (ret == 0) { 4566 out: 4567 for (index = 0; index < ret; index++) 4568 page_cache_release(pages[index]); 4569 /* just a hole. */ 4570 kfree(pages); 4571 return EXT_CONTINUE; 4572 } 4573 index = 0; 4574 4575 next_page: 4576 /* Try to find the 1st mapped buffer. */ 4577 end = ((__u64)pages[index]->index << PAGE_SHIFT) >> 4578 blksize_bits; 4579 if (!page_has_buffers(pages[index])) 4580 goto out; 4581 head = page_buffers(pages[index]); 4582 if (!head) 4583 goto out; 4584 4585 index++; 4586 bh = head; 4587 do { 4588 if (end >= newex->ec_block + 4589 newex->ec_len) 4590 /* The buffer is out of 4591 * the request range. 4592 */ 4593 goto out; 4594 4595 if (buffer_mapped(bh) && 4596 end >= newex->ec_block) { 4597 start_index = index - 1; 4598 /* get the 1st mapped buffer. */ 4599 goto found_mapped_buffer; 4600 } 4601 4602 bh = bh->b_this_page; 4603 end++; 4604 } while (bh != head); 4605 4606 /* No mapped buffer in the range found in this page, 4607 * We need to look up next page. 4608 */ 4609 if (index >= ret) { 4610 /* There is no page left, but we need to limit 4611 * newex->ec_len. 4612 */ 4613 newex->ec_len = end - newex->ec_block; 4614 goto out; 4615 } 4616 goto next_page; 4617 } else { 4618 /*Find contiguous delayed buffers. */ 4619 if (ret > 0 && pages[0]->index == last_offset) 4620 head = page_buffers(pages[0]); 4621 bh = head; 4622 index = 1; 4623 start_index = 0; 4624 } 4625 4626 found_mapped_buffer: 4627 if (bh != NULL && buffer_delay(bh)) { 4628 /* 1st or contiguous delayed buffer found. */ 4629 if (!(flags & FIEMAP_EXTENT_DELALLOC)) { 4630 /* 4631 * 1st delayed buffer found, record 4632 * the start of extent. 4633 */ 4634 flags |= FIEMAP_EXTENT_DELALLOC; 4635 newex->ec_block = end; 4636 logical = (__u64)end << blksize_bits; 4637 } 4638 /* Find contiguous delayed buffers. */ 4639 do { 4640 if (!buffer_delay(bh)) 4641 goto found_delayed_extent; 4642 bh = bh->b_this_page; 4643 end++; 4644 } while (bh != head); 4645 4646 for (; index < ret; index++) { 4647 if (!page_has_buffers(pages[index])) { 4648 bh = NULL; 4649 break; 4650 } 4651 head = page_buffers(pages[index]); 4652 if (!head) { 4653 bh = NULL; 4654 break; 4655 } 4656 4657 if (pages[index]->index != 4658 pages[start_index]->index + index 4659 - start_index) { 4660 /* Blocks are not contiguous. */ 4661 bh = NULL; 4662 break; 4663 } 4664 bh = head; 4665 do { 4666 if (!buffer_delay(bh)) 4667 /* Delayed-extent ends. */ 4668 goto found_delayed_extent; 4669 bh = bh->b_this_page; 4670 end++; 4671 } while (bh != head); 4672 } 4673 } else if (!(flags & FIEMAP_EXTENT_DELALLOC)) 4674 /* a hole found. */ 4675 goto out; 4676 4677 found_delayed_extent: 4678 newex->ec_len = min(end - newex->ec_block, 4679 (ext4_lblk_t)EXT_INIT_MAX_LEN); 4680 if (ret == nr_pages && bh != NULL && 4681 newex->ec_len < EXT_INIT_MAX_LEN && 4682 buffer_delay(bh)) { 4683 /* Have not collected an extent and continue. */ 4684 for (index = 0; index < ret; index++) 4685 page_cache_release(pages[index]); 4686 goto repeat; 4687 } 4688 4689 for (index = 0; index < ret; index++) 4690 page_cache_release(pages[index]); 4691 kfree(pages); 4692 } 4693 4694 physical = (__u64)newex->ec_start << blksize_bits; 4695 length = (__u64)newex->ec_len << blksize_bits; 4696 4697 if (ex && ext4_ext_is_uninitialized(ex)) 4698 flags |= FIEMAP_EXTENT_UNWRITTEN; 4699 4700 if (next == EXT_MAX_BLOCKS) 4701 flags |= FIEMAP_EXTENT_LAST; 4702 4703 ret = fiemap_fill_next_extent(fieinfo, logical, physical, 4704 length, flags); 4705 if (ret < 0) 4706 return ret; 4707 if (ret == 1) 4708 return EXT_BREAK; 4709 return EXT_CONTINUE; 4710 } 4711 /* fiemap flags we can handle specified here */ 4712 #define EXT4_FIEMAP_FLAGS (FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR) 4713 4714 static int ext4_xattr_fiemap(struct inode *inode, 4715 struct fiemap_extent_info *fieinfo) 4716 { 4717 __u64 physical = 0; 4718 __u64 length; 4719 __u32 flags = FIEMAP_EXTENT_LAST; 4720 int blockbits = inode->i_sb->s_blocksize_bits; 4721 int error = 0; 4722 4723 /* in-inode? */ 4724 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) { 4725 struct ext4_iloc iloc; 4726 int offset; /* offset of xattr in inode */ 4727 4728 error = ext4_get_inode_loc(inode, &iloc); 4729 if (error) 4730 return error; 4731 physical = iloc.bh->b_blocknr << blockbits; 4732 offset = EXT4_GOOD_OLD_INODE_SIZE + 4733 EXT4_I(inode)->i_extra_isize; 4734 physical += offset; 4735 length = EXT4_SB(inode->i_sb)->s_inode_size - offset; 4736 flags |= FIEMAP_EXTENT_DATA_INLINE; 4737 brelse(iloc.bh); 4738 } else { /* external block */ 4739 physical = EXT4_I(inode)->i_file_acl << blockbits; 4740 length = inode->i_sb->s_blocksize; 4741 } 4742 4743 if (physical) 4744 error = fiemap_fill_next_extent(fieinfo, 0, physical, 4745 length, flags); 4746 return (error < 0 ? error : 0); 4747 } 4748 4749 /* 4750 * ext4_ext_punch_hole 4751 * 4752 * Punches a hole of "length" bytes in a file starting 4753 * at byte "offset" 4754 * 4755 * @inode: The inode of the file to punch a hole in 4756 * @offset: The starting byte offset of the hole 4757 * @length: The length of the hole 4758 * 4759 * Returns the number of blocks removed or negative on err 4760 */ 4761 int ext4_ext_punch_hole(struct file *file, loff_t offset, loff_t length) 4762 { 4763 struct inode *inode = file->f_path.dentry->d_inode; 4764 struct super_block *sb = inode->i_sb; 4765 ext4_lblk_t first_block, stop_block; 4766 struct address_space *mapping = inode->i_mapping; 4767 handle_t *handle; 4768 loff_t first_page, last_page, page_len; 4769 loff_t first_page_offset, last_page_offset; 4770 int credits, err = 0; 4771 4772 /* No need to punch hole beyond i_size */ 4773 if (offset >= inode->i_size) 4774 return 0; 4775 4776 /* 4777 * If the hole extends beyond i_size, set the hole 4778 * to end after the page that contains i_size 4779 */ 4780 if (offset + length > inode->i_size) { 4781 length = inode->i_size + 4782 PAGE_CACHE_SIZE - (inode->i_size & (PAGE_CACHE_SIZE - 1)) - 4783 offset; 4784 } 4785 4786 first_page = (offset + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 4787 last_page = (offset + length) >> PAGE_CACHE_SHIFT; 4788 4789 first_page_offset = first_page << PAGE_CACHE_SHIFT; 4790 last_page_offset = last_page << PAGE_CACHE_SHIFT; 4791 4792 /* 4793 * Write out all dirty pages to avoid race conditions 4794 * Then release them. 4795 */ 4796 if (mapping->nrpages && mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) { 4797 err = filemap_write_and_wait_range(mapping, 4798 offset, offset + length - 1); 4799 4800 if (err) 4801 return err; 4802 } 4803 4804 /* Now release the pages */ 4805 if (last_page_offset > first_page_offset) { 4806 truncate_pagecache_range(inode, first_page_offset, 4807 last_page_offset - 1); 4808 } 4809 4810 /* finish any pending end_io work */ 4811 ext4_flush_completed_IO(inode); 4812 4813 credits = ext4_writepage_trans_blocks(inode); 4814 handle = ext4_journal_start(inode, credits); 4815 if (IS_ERR(handle)) 4816 return PTR_ERR(handle); 4817 4818 err = ext4_orphan_add(handle, inode); 4819 if (err) 4820 goto out; 4821 4822 /* 4823 * Now we need to zero out the non-page-aligned data in the 4824 * pages at the start and tail of the hole, and unmap the buffer 4825 * heads for the block aligned regions of the page that were 4826 * completely zeroed. 4827 */ 4828 if (first_page > last_page) { 4829 /* 4830 * If the file space being truncated is contained within a page 4831 * just zero out and unmap the middle of that page 4832 */ 4833 err = ext4_discard_partial_page_buffers(handle, 4834 mapping, offset, length, 0); 4835 4836 if (err) 4837 goto out; 4838 } else { 4839 /* 4840 * zero out and unmap the partial page that contains 4841 * the start of the hole 4842 */ 4843 page_len = first_page_offset - offset; 4844 if (page_len > 0) { 4845 err = ext4_discard_partial_page_buffers(handle, mapping, 4846 offset, page_len, 0); 4847 if (err) 4848 goto out; 4849 } 4850 4851 /* 4852 * zero out and unmap the partial page that contains 4853 * the end of the hole 4854 */ 4855 page_len = offset + length - last_page_offset; 4856 if (page_len > 0) { 4857 err = ext4_discard_partial_page_buffers(handle, mapping, 4858 last_page_offset, page_len, 0); 4859 if (err) 4860 goto out; 4861 } 4862 } 4863 4864 /* 4865 * If i_size is contained in the last page, we need to 4866 * unmap and zero the partial page after i_size 4867 */ 4868 if (inode->i_size >> PAGE_CACHE_SHIFT == last_page && 4869 inode->i_size % PAGE_CACHE_SIZE != 0) { 4870 4871 page_len = PAGE_CACHE_SIZE - 4872 (inode->i_size & (PAGE_CACHE_SIZE - 1)); 4873 4874 if (page_len > 0) { 4875 err = ext4_discard_partial_page_buffers(handle, 4876 mapping, inode->i_size, page_len, 0); 4877 4878 if (err) 4879 goto out; 4880 } 4881 } 4882 4883 first_block = (offset + sb->s_blocksize - 1) >> 4884 EXT4_BLOCK_SIZE_BITS(sb); 4885 stop_block = (offset + length) >> EXT4_BLOCK_SIZE_BITS(sb); 4886 4887 /* If there are no blocks to remove, return now */ 4888 if (first_block >= stop_block) 4889 goto out; 4890 4891 down_write(&EXT4_I(inode)->i_data_sem); 4892 ext4_ext_invalidate_cache(inode); 4893 ext4_discard_preallocations(inode); 4894 4895 err = ext4_ext_remove_space(inode, first_block, stop_block - 1); 4896 4897 ext4_ext_invalidate_cache(inode); 4898 ext4_discard_preallocations(inode); 4899 4900 if (IS_SYNC(inode)) 4901 ext4_handle_sync(handle); 4902 4903 up_write(&EXT4_I(inode)->i_data_sem); 4904 4905 out: 4906 ext4_orphan_del(handle, inode); 4907 inode->i_mtime = inode->i_ctime = ext4_current_time(inode); 4908 ext4_mark_inode_dirty(handle, inode); 4909 ext4_journal_stop(handle); 4910 return err; 4911 } 4912 int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, 4913 __u64 start, __u64 len) 4914 { 4915 ext4_lblk_t start_blk; 4916 int error = 0; 4917 4918 /* fallback to generic here if not in extents fmt */ 4919 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) 4920 return generic_block_fiemap(inode, fieinfo, start, len, 4921 ext4_get_block); 4922 4923 if (fiemap_check_flags(fieinfo, EXT4_FIEMAP_FLAGS)) 4924 return -EBADR; 4925 4926 if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) { 4927 error = ext4_xattr_fiemap(inode, fieinfo); 4928 } else { 4929 ext4_lblk_t len_blks; 4930 __u64 last_blk; 4931 4932 start_blk = start >> inode->i_sb->s_blocksize_bits; 4933 last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits; 4934 if (last_blk >= EXT_MAX_BLOCKS) 4935 last_blk = EXT_MAX_BLOCKS-1; 4936 len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1; 4937 4938 /* 4939 * Walk the extent tree gathering extent information. 4940 * ext4_ext_fiemap_cb will push extents back to user. 4941 */ 4942 error = ext4_ext_walk_space(inode, start_blk, len_blks, 4943 ext4_ext_fiemap_cb, fieinfo); 4944 } 4945 4946 return error; 4947 } 4948