extents.c revision 81fdbb4a8d34242f0ed048395c4ddc910f1dffbe
1/* 2 * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com 3 * Written by Alex Tomas <alex@clusterfs.com> 4 * 5 * Architecture independence: 6 * Copyright (c) 2005, Bull S.A. 7 * Written by Pierre Peiffer <pierre.peiffer@bull.net> 8 * 9 * This program is free software; you can redistribute it and/or modify 10 * it under the terms of the GNU General Public License version 2 as 11 * published by the Free Software Foundation. 12 * 13 * This program is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 * GNU General Public License for more details. 17 * 18 * You should have received a copy of the GNU General Public Licens 19 * along with this program; if not, write to the Free Software 20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111- 21 */ 22 23/* 24 * Extents support for EXT4 25 * 26 * TODO: 27 * - ext4*_error() should be used in some situations 28 * - analyze all BUG()/BUG_ON(), use -EIO where appropriate 29 * - smart tree reduction 30 */ 31 32#include <linux/module.h> 33#include <linux/fs.h> 34#include <linux/time.h> 35#include <linux/jbd2.h> 36#include <linux/highuid.h> 37#include <linux/pagemap.h> 38#include <linux/quotaops.h> 39#include <linux/string.h> 40#include <linux/slab.h> 41#include <linux/falloc.h> 42#include <asm/uaccess.h> 43#include <linux/fiemap.h> 44#include "ext4_jbd2.h" 45 46#include <trace/events/ext4.h> 47 48static int ext4_split_extent(handle_t *handle, 49 struct inode *inode, 50 struct ext4_ext_path *path, 51 struct ext4_map_blocks *map, 52 int split_flag, 53 int flags); 54 55static int ext4_ext_truncate_extend_restart(handle_t *handle, 56 struct inode *inode, 57 int needed) 58{ 59 int err; 60 61 if (!ext4_handle_valid(handle)) 62 return 0; 63 if (handle->h_buffer_credits > needed) 64 return 0; 65 err = ext4_journal_extend(handle, needed); 66 if (err <= 0) 67 return err; 68 err = ext4_truncate_restart_trans(handle, inode, needed); 69 if (err == 0) 70 err = -EAGAIN; 71 72 return err; 73} 74 75/* 76 * could return: 77 * - EROFS 78 * - ENOMEM 79 */ 80static int ext4_ext_get_access(handle_t *handle, struct inode *inode, 81 struct ext4_ext_path *path) 82{ 83 if (path->p_bh) { 84 /* path points to block */ 85 return ext4_journal_get_write_access(handle, path->p_bh); 86 } 87 /* path points to leaf/index in inode body */ 88 /* we use in-core data, no need to protect them */ 89 return 0; 90} 91 92/* 93 * could return: 94 * - EROFS 95 * - ENOMEM 96 * - EIO 97 */ 98#define ext4_ext_dirty(handle, inode, path) \ 99 __ext4_ext_dirty(__func__, __LINE__, (handle), (inode), (path)) 100static int __ext4_ext_dirty(const char *where, unsigned int line, 101 handle_t *handle, struct inode *inode, 102 struct ext4_ext_path *path) 103{ 104 int err; 105 if (path->p_bh) { 106 /* path points to block */ 107 err = __ext4_handle_dirty_metadata(where, line, handle, 108 inode, path->p_bh); 109 } else { 110 /* path points to leaf/index in inode body */ 111 err = ext4_mark_inode_dirty(handle, inode); 112 } 113 return err; 114} 115 116static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode, 117 struct ext4_ext_path *path, 118 ext4_lblk_t block) 119{ 120 if (path) { 121 int depth = path->p_depth; 122 struct ext4_extent *ex; 123 124 /* 125 * Try to predict block placement assuming that we are 126 * filling in a file which will eventually be 127 * non-sparse --- i.e., in the case of libbfd writing 128 * an ELF object sections out-of-order but in a way 129 * the eventually results in a contiguous object or 130 * executable file, or some database extending a table 131 * space file. However, this is actually somewhat 132 * non-ideal if we are writing a sparse file such as 133 * qemu or KVM writing a raw image file that is going 134 * to stay fairly sparse, since it will end up 135 * fragmenting the file system's free space. Maybe we 136 * should have some hueristics or some way to allow 137 * userspace to pass a hint to file system, 138 * especially if the latter case turns out to be 139 * common. 140 */ 141 ex = path[depth].p_ext; 142 if (ex) { 143 ext4_fsblk_t ext_pblk = ext4_ext_pblock(ex); 144 ext4_lblk_t ext_block = le32_to_cpu(ex->ee_block); 145 146 if (block > ext_block) 147 return ext_pblk + (block - ext_block); 148 else 149 return ext_pblk - (ext_block - block); 150 } 151 152 /* it looks like index is empty; 153 * try to find starting block from index itself */ 154 if (path[depth].p_bh) 155 return path[depth].p_bh->b_blocknr; 156 } 157 158 /* OK. use inode's group */ 159 return ext4_inode_to_goal_block(inode); 160} 161 162/* 163 * Allocation for a meta data block 164 */ 165static ext4_fsblk_t 166ext4_ext_new_meta_block(handle_t *handle, struct inode *inode, 167 struct ext4_ext_path *path, 168 struct ext4_extent *ex, int *err, unsigned int flags) 169{ 170 ext4_fsblk_t goal, newblock; 171 172 goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block)); 173 newblock = ext4_new_meta_blocks(handle, inode, goal, flags, 174 NULL, err); 175 return newblock; 176} 177 178static inline int ext4_ext_space_block(struct inode *inode, int check) 179{ 180 int size; 181 182 size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header)) 183 / sizeof(struct ext4_extent); 184 if (!check) { 185#ifdef AGGRESSIVE_TEST 186 if (size > 6) 187 size = 6; 188#endif 189 } 190 return size; 191} 192 193static inline int ext4_ext_space_block_idx(struct inode *inode, int check) 194{ 195 int size; 196 197 size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header)) 198 / sizeof(struct ext4_extent_idx); 199 if (!check) { 200#ifdef AGGRESSIVE_TEST 201 if (size > 5) 202 size = 5; 203#endif 204 } 205 return size; 206} 207 208static inline int ext4_ext_space_root(struct inode *inode, int check) 209{ 210 int size; 211 212 size = sizeof(EXT4_I(inode)->i_data); 213 size -= sizeof(struct ext4_extent_header); 214 size /= sizeof(struct ext4_extent); 215 if (!check) { 216#ifdef AGGRESSIVE_TEST 217 if (size > 3) 218 size = 3; 219#endif 220 } 221 return size; 222} 223 224static inline int ext4_ext_space_root_idx(struct inode *inode, int check) 225{ 226 int size; 227 228 size = sizeof(EXT4_I(inode)->i_data); 229 size -= sizeof(struct ext4_extent_header); 230 size /= sizeof(struct ext4_extent_idx); 231 if (!check) { 232#ifdef AGGRESSIVE_TEST 233 if (size > 4) 234 size = 4; 235#endif 236 } 237 return size; 238} 239 240/* 241 * Calculate the number of metadata blocks needed 242 * to allocate @blocks 243 * Worse case is one block per extent 244 */ 245int ext4_ext_calc_metadata_amount(struct inode *inode, ext4_lblk_t lblock) 246{ 247 struct ext4_inode_info *ei = EXT4_I(inode); 248 int idxs; 249 250 idxs = ((inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header)) 251 / sizeof(struct ext4_extent_idx)); 252 253 /* 254 * If the new delayed allocation block is contiguous with the 255 * previous da block, it can share index blocks with the 256 * previous block, so we only need to allocate a new index 257 * block every idxs leaf blocks. At ldxs**2 blocks, we need 258 * an additional index block, and at ldxs**3 blocks, yet 259 * another index blocks. 260 */ 261 if (ei->i_da_metadata_calc_len && 262 ei->i_da_metadata_calc_last_lblock+1 == lblock) { 263 int num = 0; 264 265 if ((ei->i_da_metadata_calc_len % idxs) == 0) 266 num++; 267 if ((ei->i_da_metadata_calc_len % (idxs*idxs)) == 0) 268 num++; 269 if ((ei->i_da_metadata_calc_len % (idxs*idxs*idxs)) == 0) { 270 num++; 271 ei->i_da_metadata_calc_len = 0; 272 } else 273 ei->i_da_metadata_calc_len++; 274 ei->i_da_metadata_calc_last_lblock++; 275 return num; 276 } 277 278 /* 279 * In the worst case we need a new set of index blocks at 280 * every level of the inode's extent tree. 281 */ 282 ei->i_da_metadata_calc_len = 1; 283 ei->i_da_metadata_calc_last_lblock = lblock; 284 return ext_depth(inode) + 1; 285} 286 287static int 288ext4_ext_max_entries(struct inode *inode, int depth) 289{ 290 int max; 291 292 if (depth == ext_depth(inode)) { 293 if (depth == 0) 294 max = ext4_ext_space_root(inode, 1); 295 else 296 max = ext4_ext_space_root_idx(inode, 1); 297 } else { 298 if (depth == 0) 299 max = ext4_ext_space_block(inode, 1); 300 else 301 max = ext4_ext_space_block_idx(inode, 1); 302 } 303 304 return max; 305} 306 307static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext) 308{ 309 ext4_fsblk_t block = ext4_ext_pblock(ext); 310 int len = ext4_ext_get_actual_len(ext); 311 312 return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, len); 313} 314 315static int ext4_valid_extent_idx(struct inode *inode, 316 struct ext4_extent_idx *ext_idx) 317{ 318 ext4_fsblk_t block = ext4_idx_pblock(ext_idx); 319 320 return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, 1); 321} 322 323static int ext4_valid_extent_entries(struct inode *inode, 324 struct ext4_extent_header *eh, 325 int depth) 326{ 327 unsigned short entries; 328 if (eh->eh_entries == 0) 329 return 1; 330 331 entries = le16_to_cpu(eh->eh_entries); 332 333 if (depth == 0) { 334 /* leaf entries */ 335 struct ext4_extent *ext = EXT_FIRST_EXTENT(eh); 336 while (entries) { 337 if (!ext4_valid_extent(inode, ext)) 338 return 0; 339 ext++; 340 entries--; 341 } 342 } else { 343 struct ext4_extent_idx *ext_idx = EXT_FIRST_INDEX(eh); 344 while (entries) { 345 if (!ext4_valid_extent_idx(inode, ext_idx)) 346 return 0; 347 ext_idx++; 348 entries--; 349 } 350 } 351 return 1; 352} 353 354static int __ext4_ext_check(const char *function, unsigned int line, 355 struct inode *inode, struct ext4_extent_header *eh, 356 int depth) 357{ 358 const char *error_msg; 359 int max = 0; 360 361 if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) { 362 error_msg = "invalid magic"; 363 goto corrupted; 364 } 365 if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) { 366 error_msg = "unexpected eh_depth"; 367 goto corrupted; 368 } 369 if (unlikely(eh->eh_max == 0)) { 370 error_msg = "invalid eh_max"; 371 goto corrupted; 372 } 373 max = ext4_ext_max_entries(inode, depth); 374 if (unlikely(le16_to_cpu(eh->eh_max) > max)) { 375 error_msg = "too large eh_max"; 376 goto corrupted; 377 } 378 if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) { 379 error_msg = "invalid eh_entries"; 380 goto corrupted; 381 } 382 if (!ext4_valid_extent_entries(inode, eh, depth)) { 383 error_msg = "invalid extent entries"; 384 goto corrupted; 385 } 386 return 0; 387 388corrupted: 389 ext4_error_inode(inode, function, line, 0, 390 "bad header/extent: %s - magic %x, " 391 "entries %u, max %u(%u), depth %u(%u)", 392 error_msg, le16_to_cpu(eh->eh_magic), 393 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max), 394 max, le16_to_cpu(eh->eh_depth), depth); 395 396 return -EIO; 397} 398 399#define ext4_ext_check(inode, eh, depth) \ 400 __ext4_ext_check(__func__, __LINE__, inode, eh, depth) 401 402int ext4_ext_check_inode(struct inode *inode) 403{ 404 return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode)); 405} 406 407#ifdef EXT_DEBUG 408static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path) 409{ 410 int k, l = path->p_depth; 411 412 ext_debug("path:"); 413 for (k = 0; k <= l; k++, path++) { 414 if (path->p_idx) { 415 ext_debug(" %d->%llu", le32_to_cpu(path->p_idx->ei_block), 416 ext4_idx_pblock(path->p_idx)); 417 } else if (path->p_ext) { 418 ext_debug(" %d:[%d]%d:%llu ", 419 le32_to_cpu(path->p_ext->ee_block), 420 ext4_ext_is_uninitialized(path->p_ext), 421 ext4_ext_get_actual_len(path->p_ext), 422 ext4_ext_pblock(path->p_ext)); 423 } else 424 ext_debug(" []"); 425 } 426 ext_debug("\n"); 427} 428 429static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path) 430{ 431 int depth = ext_depth(inode); 432 struct ext4_extent_header *eh; 433 struct ext4_extent *ex; 434 int i; 435 436 if (!path) 437 return; 438 439 eh = path[depth].p_hdr; 440 ex = EXT_FIRST_EXTENT(eh); 441 442 ext_debug("Displaying leaf extents for inode %lu\n", inode->i_ino); 443 444 for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) { 445 ext_debug("%d:[%d]%d:%llu ", le32_to_cpu(ex->ee_block), 446 ext4_ext_is_uninitialized(ex), 447 ext4_ext_get_actual_len(ex), ext4_ext_pblock(ex)); 448 } 449 ext_debug("\n"); 450} 451 452static void ext4_ext_show_move(struct inode *inode, struct ext4_ext_path *path, 453 ext4_fsblk_t newblock, int level) 454{ 455 int depth = ext_depth(inode); 456 struct ext4_extent *ex; 457 458 if (depth != level) { 459 struct ext4_extent_idx *idx; 460 idx = path[level].p_idx; 461 while (idx <= EXT_MAX_INDEX(path[level].p_hdr)) { 462 ext_debug("%d: move %d:%llu in new index %llu\n", level, 463 le32_to_cpu(idx->ei_block), 464 ext4_idx_pblock(idx), 465 newblock); 466 idx++; 467 } 468 469 return; 470 } 471 472 ex = path[depth].p_ext; 473 while (ex <= EXT_MAX_EXTENT(path[depth].p_hdr)) { 474 ext_debug("move %d:%llu:[%d]%d in new leaf %llu\n", 475 le32_to_cpu(ex->ee_block), 476 ext4_ext_pblock(ex), 477 ext4_ext_is_uninitialized(ex), 478 ext4_ext_get_actual_len(ex), 479 newblock); 480 ex++; 481 } 482} 483 484#else 485#define ext4_ext_show_path(inode, path) 486#define ext4_ext_show_leaf(inode, path) 487#define ext4_ext_show_move(inode, path, newblock, level) 488#endif 489 490void ext4_ext_drop_refs(struct ext4_ext_path *path) 491{ 492 int depth = path->p_depth; 493 int i; 494 495 for (i = 0; i <= depth; i++, path++) 496 if (path->p_bh) { 497 brelse(path->p_bh); 498 path->p_bh = NULL; 499 } 500} 501 502/* 503 * ext4_ext_binsearch_idx: 504 * binary search for the closest index of the given block 505 * the header must be checked before calling this 506 */ 507static void 508ext4_ext_binsearch_idx(struct inode *inode, 509 struct ext4_ext_path *path, ext4_lblk_t block) 510{ 511 struct ext4_extent_header *eh = path->p_hdr; 512 struct ext4_extent_idx *r, *l, *m; 513 514 515 ext_debug("binsearch for %u(idx): ", block); 516 517 l = EXT_FIRST_INDEX(eh) + 1; 518 r = EXT_LAST_INDEX(eh); 519 while (l <= r) { 520 m = l + (r - l) / 2; 521 if (block < le32_to_cpu(m->ei_block)) 522 r = m - 1; 523 else 524 l = m + 1; 525 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ei_block), 526 m, le32_to_cpu(m->ei_block), 527 r, le32_to_cpu(r->ei_block)); 528 } 529 530 path->p_idx = l - 1; 531 ext_debug(" -> %d->%lld ", le32_to_cpu(path->p_idx->ei_block), 532 ext4_idx_pblock(path->p_idx)); 533 534#ifdef CHECK_BINSEARCH 535 { 536 struct ext4_extent_idx *chix, *ix; 537 int k; 538 539 chix = ix = EXT_FIRST_INDEX(eh); 540 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) { 541 if (k != 0 && 542 le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) { 543 printk(KERN_DEBUG "k=%d, ix=0x%p, " 544 "first=0x%p\n", k, 545 ix, EXT_FIRST_INDEX(eh)); 546 printk(KERN_DEBUG "%u <= %u\n", 547 le32_to_cpu(ix->ei_block), 548 le32_to_cpu(ix[-1].ei_block)); 549 } 550 BUG_ON(k && le32_to_cpu(ix->ei_block) 551 <= le32_to_cpu(ix[-1].ei_block)); 552 if (block < le32_to_cpu(ix->ei_block)) 553 break; 554 chix = ix; 555 } 556 BUG_ON(chix != path->p_idx); 557 } 558#endif 559 560} 561 562/* 563 * ext4_ext_binsearch: 564 * binary search for closest extent of the given block 565 * the header must be checked before calling this 566 */ 567static void 568ext4_ext_binsearch(struct inode *inode, 569 struct ext4_ext_path *path, ext4_lblk_t block) 570{ 571 struct ext4_extent_header *eh = path->p_hdr; 572 struct ext4_extent *r, *l, *m; 573 574 if (eh->eh_entries == 0) { 575 /* 576 * this leaf is empty: 577 * we get such a leaf in split/add case 578 */ 579 return; 580 } 581 582 ext_debug("binsearch for %u: ", block); 583 584 l = EXT_FIRST_EXTENT(eh) + 1; 585 r = EXT_LAST_EXTENT(eh); 586 587 while (l <= r) { 588 m = l + (r - l) / 2; 589 if (block < le32_to_cpu(m->ee_block)) 590 r = m - 1; 591 else 592 l = m + 1; 593 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ee_block), 594 m, le32_to_cpu(m->ee_block), 595 r, le32_to_cpu(r->ee_block)); 596 } 597 598 path->p_ext = l - 1; 599 ext_debug(" -> %d:%llu:[%d]%d ", 600 le32_to_cpu(path->p_ext->ee_block), 601 ext4_ext_pblock(path->p_ext), 602 ext4_ext_is_uninitialized(path->p_ext), 603 ext4_ext_get_actual_len(path->p_ext)); 604 605#ifdef CHECK_BINSEARCH 606 { 607 struct ext4_extent *chex, *ex; 608 int k; 609 610 chex = ex = EXT_FIRST_EXTENT(eh); 611 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) { 612 BUG_ON(k && le32_to_cpu(ex->ee_block) 613 <= le32_to_cpu(ex[-1].ee_block)); 614 if (block < le32_to_cpu(ex->ee_block)) 615 break; 616 chex = ex; 617 } 618 BUG_ON(chex != path->p_ext); 619 } 620#endif 621 622} 623 624int ext4_ext_tree_init(handle_t *handle, struct inode *inode) 625{ 626 struct ext4_extent_header *eh; 627 628 eh = ext_inode_hdr(inode); 629 eh->eh_depth = 0; 630 eh->eh_entries = 0; 631 eh->eh_magic = EXT4_EXT_MAGIC; 632 eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode, 0)); 633 ext4_mark_inode_dirty(handle, inode); 634 ext4_ext_invalidate_cache(inode); 635 return 0; 636} 637 638struct ext4_ext_path * 639ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block, 640 struct ext4_ext_path *path) 641{ 642 struct ext4_extent_header *eh; 643 struct buffer_head *bh; 644 short int depth, i, ppos = 0, alloc = 0; 645 646 eh = ext_inode_hdr(inode); 647 depth = ext_depth(inode); 648 649 /* account possible depth increase */ 650 if (!path) { 651 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2), 652 GFP_NOFS); 653 if (!path) 654 return ERR_PTR(-ENOMEM); 655 alloc = 1; 656 } 657 path[0].p_hdr = eh; 658 path[0].p_bh = NULL; 659 660 i = depth; 661 /* walk through the tree */ 662 while (i) { 663 int need_to_validate = 0; 664 665 ext_debug("depth %d: num %d, max %d\n", 666 ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max)); 667 668 ext4_ext_binsearch_idx(inode, path + ppos, block); 669 path[ppos].p_block = ext4_idx_pblock(path[ppos].p_idx); 670 path[ppos].p_depth = i; 671 path[ppos].p_ext = NULL; 672 673 bh = sb_getblk(inode->i_sb, path[ppos].p_block); 674 if (unlikely(!bh)) 675 goto err; 676 if (!bh_uptodate_or_lock(bh)) { 677 trace_ext4_ext_load_extent(inode, block, 678 path[ppos].p_block); 679 if (bh_submit_read(bh) < 0) { 680 put_bh(bh); 681 goto err; 682 } 683 /* validate the extent entries */ 684 need_to_validate = 1; 685 } 686 eh = ext_block_hdr(bh); 687 ppos++; 688 if (unlikely(ppos > depth)) { 689 put_bh(bh); 690 EXT4_ERROR_INODE(inode, 691 "ppos %d > depth %d", ppos, depth); 692 goto err; 693 } 694 path[ppos].p_bh = bh; 695 path[ppos].p_hdr = eh; 696 i--; 697 698 if (need_to_validate && ext4_ext_check(inode, eh, i)) 699 goto err; 700 } 701 702 path[ppos].p_depth = i; 703 path[ppos].p_ext = NULL; 704 path[ppos].p_idx = NULL; 705 706 /* find extent */ 707 ext4_ext_binsearch(inode, path + ppos, block); 708 /* if not an empty leaf */ 709 if (path[ppos].p_ext) 710 path[ppos].p_block = ext4_ext_pblock(path[ppos].p_ext); 711 712 ext4_ext_show_path(inode, path); 713 714 return path; 715 716err: 717 ext4_ext_drop_refs(path); 718 if (alloc) 719 kfree(path); 720 return ERR_PTR(-EIO); 721} 722 723/* 724 * ext4_ext_insert_index: 725 * insert new index [@logical;@ptr] into the block at @curp; 726 * check where to insert: before @curp or after @curp 727 */ 728static int ext4_ext_insert_index(handle_t *handle, struct inode *inode, 729 struct ext4_ext_path *curp, 730 int logical, ext4_fsblk_t ptr) 731{ 732 struct ext4_extent_idx *ix; 733 int len, err; 734 735 err = ext4_ext_get_access(handle, inode, curp); 736 if (err) 737 return err; 738 739 if (unlikely(logical == le32_to_cpu(curp->p_idx->ei_block))) { 740 EXT4_ERROR_INODE(inode, 741 "logical %d == ei_block %d!", 742 logical, le32_to_cpu(curp->p_idx->ei_block)); 743 return -EIO; 744 } 745 746 if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries) 747 >= le16_to_cpu(curp->p_hdr->eh_max))) { 748 EXT4_ERROR_INODE(inode, 749 "eh_entries %d >= eh_max %d!", 750 le16_to_cpu(curp->p_hdr->eh_entries), 751 le16_to_cpu(curp->p_hdr->eh_max)); 752 return -EIO; 753 } 754 755 if (logical > le32_to_cpu(curp->p_idx->ei_block)) { 756 /* insert after */ 757 ext_debug("insert new index %d after: %llu\n", logical, ptr); 758 ix = curp->p_idx + 1; 759 } else { 760 /* insert before */ 761 ext_debug("insert new index %d before: %llu\n", logical, ptr); 762 ix = curp->p_idx; 763 } 764 765 len = EXT_LAST_INDEX(curp->p_hdr) - ix + 1; 766 BUG_ON(len < 0); 767 if (len > 0) { 768 ext_debug("insert new index %d: " 769 "move %d indices from 0x%p to 0x%p\n", 770 logical, len, ix, ix + 1); 771 memmove(ix + 1, ix, len * sizeof(struct ext4_extent_idx)); 772 } 773 774 if (unlikely(ix > EXT_MAX_INDEX(curp->p_hdr))) { 775 EXT4_ERROR_INODE(inode, "ix > EXT_MAX_INDEX!"); 776 return -EIO; 777 } 778 779 ix->ei_block = cpu_to_le32(logical); 780 ext4_idx_store_pblock(ix, ptr); 781 le16_add_cpu(&curp->p_hdr->eh_entries, 1); 782 783 if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) { 784 EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!"); 785 return -EIO; 786 } 787 788 err = ext4_ext_dirty(handle, inode, curp); 789 ext4_std_error(inode->i_sb, err); 790 791 return err; 792} 793 794/* 795 * ext4_ext_split: 796 * inserts new subtree into the path, using free index entry 797 * at depth @at: 798 * - allocates all needed blocks (new leaf and all intermediate index blocks) 799 * - makes decision where to split 800 * - moves remaining extents and index entries (right to the split point) 801 * into the newly allocated blocks 802 * - initializes subtree 803 */ 804static int ext4_ext_split(handle_t *handle, struct inode *inode, 805 unsigned int flags, 806 struct ext4_ext_path *path, 807 struct ext4_extent *newext, int at) 808{ 809 struct buffer_head *bh = NULL; 810 int depth = ext_depth(inode); 811 struct ext4_extent_header *neh; 812 struct ext4_extent_idx *fidx; 813 int i = at, k, m, a; 814 ext4_fsblk_t newblock, oldblock; 815 __le32 border; 816 ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */ 817 int err = 0; 818 819 /* make decision: where to split? */ 820 /* FIXME: now decision is simplest: at current extent */ 821 822 /* if current leaf will be split, then we should use 823 * border from split point */ 824 if (unlikely(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr))) { 825 EXT4_ERROR_INODE(inode, "p_ext > EXT_MAX_EXTENT!"); 826 return -EIO; 827 } 828 if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) { 829 border = path[depth].p_ext[1].ee_block; 830 ext_debug("leaf will be split." 831 " next leaf starts at %d\n", 832 le32_to_cpu(border)); 833 } else { 834 border = newext->ee_block; 835 ext_debug("leaf will be added." 836 " next leaf starts at %d\n", 837 le32_to_cpu(border)); 838 } 839 840 /* 841 * If error occurs, then we break processing 842 * and mark filesystem read-only. index won't 843 * be inserted and tree will be in consistent 844 * state. Next mount will repair buffers too. 845 */ 846 847 /* 848 * Get array to track all allocated blocks. 849 * We need this to handle errors and free blocks 850 * upon them. 851 */ 852 ablocks = kzalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS); 853 if (!ablocks) 854 return -ENOMEM; 855 856 /* allocate all needed blocks */ 857 ext_debug("allocate %d blocks for indexes/leaf\n", depth - at); 858 for (a = 0; a < depth - at; a++) { 859 newblock = ext4_ext_new_meta_block(handle, inode, path, 860 newext, &err, flags); 861 if (newblock == 0) 862 goto cleanup; 863 ablocks[a] = newblock; 864 } 865 866 /* initialize new leaf */ 867 newblock = ablocks[--a]; 868 if (unlikely(newblock == 0)) { 869 EXT4_ERROR_INODE(inode, "newblock == 0!"); 870 err = -EIO; 871 goto cleanup; 872 } 873 bh = sb_getblk(inode->i_sb, newblock); 874 if (!bh) { 875 err = -EIO; 876 goto cleanup; 877 } 878 lock_buffer(bh); 879 880 err = ext4_journal_get_create_access(handle, bh); 881 if (err) 882 goto cleanup; 883 884 neh = ext_block_hdr(bh); 885 neh->eh_entries = 0; 886 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0)); 887 neh->eh_magic = EXT4_EXT_MAGIC; 888 neh->eh_depth = 0; 889 890 /* move remainder of path[depth] to the new leaf */ 891 if (unlikely(path[depth].p_hdr->eh_entries != 892 path[depth].p_hdr->eh_max)) { 893 EXT4_ERROR_INODE(inode, "eh_entries %d != eh_max %d!", 894 path[depth].p_hdr->eh_entries, 895 path[depth].p_hdr->eh_max); 896 err = -EIO; 897 goto cleanup; 898 } 899 /* start copy from next extent */ 900 m = EXT_MAX_EXTENT(path[depth].p_hdr) - path[depth].p_ext++; 901 ext4_ext_show_move(inode, path, newblock, depth); 902 if (m) { 903 struct ext4_extent *ex; 904 ex = EXT_FIRST_EXTENT(neh); 905 memmove(ex, path[depth].p_ext, sizeof(struct ext4_extent) * m); 906 le16_add_cpu(&neh->eh_entries, m); 907 } 908 909 set_buffer_uptodate(bh); 910 unlock_buffer(bh); 911 912 err = ext4_handle_dirty_metadata(handle, inode, bh); 913 if (err) 914 goto cleanup; 915 brelse(bh); 916 bh = NULL; 917 918 /* correct old leaf */ 919 if (m) { 920 err = ext4_ext_get_access(handle, inode, path + depth); 921 if (err) 922 goto cleanup; 923 le16_add_cpu(&path[depth].p_hdr->eh_entries, -m); 924 err = ext4_ext_dirty(handle, inode, path + depth); 925 if (err) 926 goto cleanup; 927 928 } 929 930 /* create intermediate indexes */ 931 k = depth - at - 1; 932 if (unlikely(k < 0)) { 933 EXT4_ERROR_INODE(inode, "k %d < 0!", k); 934 err = -EIO; 935 goto cleanup; 936 } 937 if (k) 938 ext_debug("create %d intermediate indices\n", k); 939 /* insert new index into current index block */ 940 /* current depth stored in i var */ 941 i = depth - 1; 942 while (k--) { 943 oldblock = newblock; 944 newblock = ablocks[--a]; 945 bh = sb_getblk(inode->i_sb, newblock); 946 if (!bh) { 947 err = -EIO; 948 goto cleanup; 949 } 950 lock_buffer(bh); 951 952 err = ext4_journal_get_create_access(handle, bh); 953 if (err) 954 goto cleanup; 955 956 neh = ext_block_hdr(bh); 957 neh->eh_entries = cpu_to_le16(1); 958 neh->eh_magic = EXT4_EXT_MAGIC; 959 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0)); 960 neh->eh_depth = cpu_to_le16(depth - i); 961 fidx = EXT_FIRST_INDEX(neh); 962 fidx->ei_block = border; 963 ext4_idx_store_pblock(fidx, oldblock); 964 965 ext_debug("int.index at %d (block %llu): %u -> %llu\n", 966 i, newblock, le32_to_cpu(border), oldblock); 967 968 /* move remainder of path[i] to the new index block */ 969 if (unlikely(EXT_MAX_INDEX(path[i].p_hdr) != 970 EXT_LAST_INDEX(path[i].p_hdr))) { 971 EXT4_ERROR_INODE(inode, 972 "EXT_MAX_INDEX != EXT_LAST_INDEX ee_block %d!", 973 le32_to_cpu(path[i].p_ext->ee_block)); 974 err = -EIO; 975 goto cleanup; 976 } 977 /* start copy indexes */ 978 m = EXT_MAX_INDEX(path[i].p_hdr) - path[i].p_idx++; 979 ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx, 980 EXT_MAX_INDEX(path[i].p_hdr)); 981 ext4_ext_show_move(inode, path, newblock, i); 982 if (m) { 983 memmove(++fidx, path[i].p_idx, 984 sizeof(struct ext4_extent_idx) * m); 985 le16_add_cpu(&neh->eh_entries, m); 986 } 987 set_buffer_uptodate(bh); 988 unlock_buffer(bh); 989 990 err = ext4_handle_dirty_metadata(handle, inode, bh); 991 if (err) 992 goto cleanup; 993 brelse(bh); 994 bh = NULL; 995 996 /* correct old index */ 997 if (m) { 998 err = ext4_ext_get_access(handle, inode, path + i); 999 if (err) 1000 goto cleanup; 1001 le16_add_cpu(&path[i].p_hdr->eh_entries, -m); 1002 err = ext4_ext_dirty(handle, inode, path + i); 1003 if (err) 1004 goto cleanup; 1005 } 1006 1007 i--; 1008 } 1009 1010 /* insert new index */ 1011 err = ext4_ext_insert_index(handle, inode, path + at, 1012 le32_to_cpu(border), newblock); 1013 1014cleanup: 1015 if (bh) { 1016 if (buffer_locked(bh)) 1017 unlock_buffer(bh); 1018 brelse(bh); 1019 } 1020 1021 if (err) { 1022 /* free all allocated blocks in error case */ 1023 for (i = 0; i < depth; i++) { 1024 if (!ablocks[i]) 1025 continue; 1026 ext4_free_blocks(handle, inode, NULL, ablocks[i], 1, 1027 EXT4_FREE_BLOCKS_METADATA); 1028 } 1029 } 1030 kfree(ablocks); 1031 1032 return err; 1033} 1034 1035/* 1036 * ext4_ext_grow_indepth: 1037 * implements tree growing procedure: 1038 * - allocates new block 1039 * - moves top-level data (index block or leaf) into the new block 1040 * - initializes new top-level, creating index that points to the 1041 * just created block 1042 */ 1043static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode, 1044 unsigned int flags, 1045 struct ext4_extent *newext) 1046{ 1047 struct ext4_extent_header *neh; 1048 struct buffer_head *bh; 1049 ext4_fsblk_t newblock; 1050 int err = 0; 1051 1052 newblock = ext4_ext_new_meta_block(handle, inode, NULL, 1053 newext, &err, flags); 1054 if (newblock == 0) 1055 return err; 1056 1057 bh = sb_getblk(inode->i_sb, newblock); 1058 if (!bh) { 1059 err = -EIO; 1060 ext4_std_error(inode->i_sb, err); 1061 return err; 1062 } 1063 lock_buffer(bh); 1064 1065 err = ext4_journal_get_create_access(handle, bh); 1066 if (err) { 1067 unlock_buffer(bh); 1068 goto out; 1069 } 1070 1071 /* move top-level index/leaf into new block */ 1072 memmove(bh->b_data, EXT4_I(inode)->i_data, 1073 sizeof(EXT4_I(inode)->i_data)); 1074 1075 /* set size of new block */ 1076 neh = ext_block_hdr(bh); 1077 /* old root could have indexes or leaves 1078 * so calculate e_max right way */ 1079 if (ext_depth(inode)) 1080 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0)); 1081 else 1082 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0)); 1083 neh->eh_magic = EXT4_EXT_MAGIC; 1084 set_buffer_uptodate(bh); 1085 unlock_buffer(bh); 1086 1087 err = ext4_handle_dirty_metadata(handle, inode, bh); 1088 if (err) 1089 goto out; 1090 1091 /* Update top-level index: num,max,pointer */ 1092 neh = ext_inode_hdr(inode); 1093 neh->eh_entries = cpu_to_le16(1); 1094 ext4_idx_store_pblock(EXT_FIRST_INDEX(neh), newblock); 1095 if (neh->eh_depth == 0) { 1096 /* Root extent block becomes index block */ 1097 neh->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode, 0)); 1098 EXT_FIRST_INDEX(neh)->ei_block = 1099 EXT_FIRST_EXTENT(neh)->ee_block; 1100 } 1101 ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n", 1102 le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max), 1103 le32_to_cpu(EXT_FIRST_INDEX(neh)->ei_block), 1104 ext4_idx_pblock(EXT_FIRST_INDEX(neh))); 1105 1106 neh->eh_depth = cpu_to_le16(neh->eh_depth + 1); 1107 ext4_mark_inode_dirty(handle, inode); 1108out: 1109 brelse(bh); 1110 1111 return err; 1112} 1113 1114/* 1115 * ext4_ext_create_new_leaf: 1116 * finds empty index and adds new leaf. 1117 * if no free index is found, then it requests in-depth growing. 1118 */ 1119static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode, 1120 unsigned int flags, 1121 struct ext4_ext_path *path, 1122 struct ext4_extent *newext) 1123{ 1124 struct ext4_ext_path *curp; 1125 int depth, i, err = 0; 1126 1127repeat: 1128 i = depth = ext_depth(inode); 1129 1130 /* walk up to the tree and look for free index entry */ 1131 curp = path + depth; 1132 while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) { 1133 i--; 1134 curp--; 1135 } 1136 1137 /* we use already allocated block for index block, 1138 * so subsequent data blocks should be contiguous */ 1139 if (EXT_HAS_FREE_INDEX(curp)) { 1140 /* if we found index with free entry, then use that 1141 * entry: create all needed subtree and add new leaf */ 1142 err = ext4_ext_split(handle, inode, flags, path, newext, i); 1143 if (err) 1144 goto out; 1145 1146 /* refill path */ 1147 ext4_ext_drop_refs(path); 1148 path = ext4_ext_find_extent(inode, 1149 (ext4_lblk_t)le32_to_cpu(newext->ee_block), 1150 path); 1151 if (IS_ERR(path)) 1152 err = PTR_ERR(path); 1153 } else { 1154 /* tree is full, time to grow in depth */ 1155 err = ext4_ext_grow_indepth(handle, inode, flags, newext); 1156 if (err) 1157 goto out; 1158 1159 /* refill path */ 1160 ext4_ext_drop_refs(path); 1161 path = ext4_ext_find_extent(inode, 1162 (ext4_lblk_t)le32_to_cpu(newext->ee_block), 1163 path); 1164 if (IS_ERR(path)) { 1165 err = PTR_ERR(path); 1166 goto out; 1167 } 1168 1169 /* 1170 * only first (depth 0 -> 1) produces free space; 1171 * in all other cases we have to split the grown tree 1172 */ 1173 depth = ext_depth(inode); 1174 if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) { 1175 /* now we need to split */ 1176 goto repeat; 1177 } 1178 } 1179 1180out: 1181 return err; 1182} 1183 1184/* 1185 * search the closest allocated block to the left for *logical 1186 * and returns it at @logical + it's physical address at @phys 1187 * if *logical is the smallest allocated block, the function 1188 * returns 0 at @phys 1189 * return value contains 0 (success) or error code 1190 */ 1191static int ext4_ext_search_left(struct inode *inode, 1192 struct ext4_ext_path *path, 1193 ext4_lblk_t *logical, ext4_fsblk_t *phys) 1194{ 1195 struct ext4_extent_idx *ix; 1196 struct ext4_extent *ex; 1197 int depth, ee_len; 1198 1199 if (unlikely(path == NULL)) { 1200 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical); 1201 return -EIO; 1202 } 1203 depth = path->p_depth; 1204 *phys = 0; 1205 1206 if (depth == 0 && path->p_ext == NULL) 1207 return 0; 1208 1209 /* usually extent in the path covers blocks smaller 1210 * then *logical, but it can be that extent is the 1211 * first one in the file */ 1212 1213 ex = path[depth].p_ext; 1214 ee_len = ext4_ext_get_actual_len(ex); 1215 if (*logical < le32_to_cpu(ex->ee_block)) { 1216 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) { 1217 EXT4_ERROR_INODE(inode, 1218 "EXT_FIRST_EXTENT != ex *logical %d ee_block %d!", 1219 *logical, le32_to_cpu(ex->ee_block)); 1220 return -EIO; 1221 } 1222 while (--depth >= 0) { 1223 ix = path[depth].p_idx; 1224 if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) { 1225 EXT4_ERROR_INODE(inode, 1226 "ix (%d) != EXT_FIRST_INDEX (%d) (depth %d)!", 1227 ix != NULL ? le32_to_cpu(ix->ei_block) : 0, 1228 EXT_FIRST_INDEX(path[depth].p_hdr) != NULL ? 1229 le32_to_cpu(EXT_FIRST_INDEX(path[depth].p_hdr)->ei_block) : 0, 1230 depth); 1231 return -EIO; 1232 } 1233 } 1234 return 0; 1235 } 1236 1237 if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) { 1238 EXT4_ERROR_INODE(inode, 1239 "logical %d < ee_block %d + ee_len %d!", 1240 *logical, le32_to_cpu(ex->ee_block), ee_len); 1241 return -EIO; 1242 } 1243 1244 *logical = le32_to_cpu(ex->ee_block) + ee_len - 1; 1245 *phys = ext4_ext_pblock(ex) + ee_len - 1; 1246 return 0; 1247} 1248 1249/* 1250 * search the closest allocated block to the right for *logical 1251 * and returns it at @logical + it's physical address at @phys 1252 * if *logical is the largest allocated block, the function 1253 * returns 0 at @phys 1254 * return value contains 0 (success) or error code 1255 */ 1256static int ext4_ext_search_right(struct inode *inode, 1257 struct ext4_ext_path *path, 1258 ext4_lblk_t *logical, ext4_fsblk_t *phys, 1259 struct ext4_extent **ret_ex) 1260{ 1261 struct buffer_head *bh = NULL; 1262 struct ext4_extent_header *eh; 1263 struct ext4_extent_idx *ix; 1264 struct ext4_extent *ex; 1265 ext4_fsblk_t block; 1266 int depth; /* Note, NOT eh_depth; depth from top of tree */ 1267 int ee_len; 1268 1269 if (unlikely(path == NULL)) { 1270 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical); 1271 return -EIO; 1272 } 1273 depth = path->p_depth; 1274 *phys = 0; 1275 1276 if (depth == 0 && path->p_ext == NULL) 1277 return 0; 1278 1279 /* usually extent in the path covers blocks smaller 1280 * then *logical, but it can be that extent is the 1281 * first one in the file */ 1282 1283 ex = path[depth].p_ext; 1284 ee_len = ext4_ext_get_actual_len(ex); 1285 if (*logical < le32_to_cpu(ex->ee_block)) { 1286 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) { 1287 EXT4_ERROR_INODE(inode, 1288 "first_extent(path[%d].p_hdr) != ex", 1289 depth); 1290 return -EIO; 1291 } 1292 while (--depth >= 0) { 1293 ix = path[depth].p_idx; 1294 if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) { 1295 EXT4_ERROR_INODE(inode, 1296 "ix != EXT_FIRST_INDEX *logical %d!", 1297 *logical); 1298 return -EIO; 1299 } 1300 } 1301 goto found_extent; 1302 } 1303 1304 if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) { 1305 EXT4_ERROR_INODE(inode, 1306 "logical %d < ee_block %d + ee_len %d!", 1307 *logical, le32_to_cpu(ex->ee_block), ee_len); 1308 return -EIO; 1309 } 1310 1311 if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) { 1312 /* next allocated block in this leaf */ 1313 ex++; 1314 goto found_extent; 1315 } 1316 1317 /* go up and search for index to the right */ 1318 while (--depth >= 0) { 1319 ix = path[depth].p_idx; 1320 if (ix != EXT_LAST_INDEX(path[depth].p_hdr)) 1321 goto got_index; 1322 } 1323 1324 /* we've gone up to the root and found no index to the right */ 1325 return 0; 1326 1327got_index: 1328 /* we've found index to the right, let's 1329 * follow it and find the closest allocated 1330 * block to the right */ 1331 ix++; 1332 block = ext4_idx_pblock(ix); 1333 while (++depth < path->p_depth) { 1334 bh = sb_bread(inode->i_sb, block); 1335 if (bh == NULL) 1336 return -EIO; 1337 eh = ext_block_hdr(bh); 1338 /* subtract from p_depth to get proper eh_depth */ 1339 if (ext4_ext_check(inode, eh, path->p_depth - depth)) { 1340 put_bh(bh); 1341 return -EIO; 1342 } 1343 ix = EXT_FIRST_INDEX(eh); 1344 block = ext4_idx_pblock(ix); 1345 put_bh(bh); 1346 } 1347 1348 bh = sb_bread(inode->i_sb, block); 1349 if (bh == NULL) 1350 return -EIO; 1351 eh = ext_block_hdr(bh); 1352 if (ext4_ext_check(inode, eh, path->p_depth - depth)) { 1353 put_bh(bh); 1354 return -EIO; 1355 } 1356 ex = EXT_FIRST_EXTENT(eh); 1357found_extent: 1358 *logical = le32_to_cpu(ex->ee_block); 1359 *phys = ext4_ext_pblock(ex); 1360 *ret_ex = ex; 1361 if (bh) 1362 put_bh(bh); 1363 return 0; 1364} 1365 1366/* 1367 * ext4_ext_next_allocated_block: 1368 * returns allocated block in subsequent extent or EXT_MAX_BLOCKS. 1369 * NOTE: it considers block number from index entry as 1370 * allocated block. Thus, index entries have to be consistent 1371 * with leaves. 1372 */ 1373static ext4_lblk_t 1374ext4_ext_next_allocated_block(struct ext4_ext_path *path) 1375{ 1376 int depth; 1377 1378 BUG_ON(path == NULL); 1379 depth = path->p_depth; 1380 1381 if (depth == 0 && path->p_ext == NULL) 1382 return EXT_MAX_BLOCKS; 1383 1384 while (depth >= 0) { 1385 if (depth == path->p_depth) { 1386 /* leaf */ 1387 if (path[depth].p_ext && 1388 path[depth].p_ext != 1389 EXT_LAST_EXTENT(path[depth].p_hdr)) 1390 return le32_to_cpu(path[depth].p_ext[1].ee_block); 1391 } else { 1392 /* index */ 1393 if (path[depth].p_idx != 1394 EXT_LAST_INDEX(path[depth].p_hdr)) 1395 return le32_to_cpu(path[depth].p_idx[1].ei_block); 1396 } 1397 depth--; 1398 } 1399 1400 return EXT_MAX_BLOCKS; 1401} 1402 1403/* 1404 * ext4_ext_next_leaf_block: 1405 * returns first allocated block from next leaf or EXT_MAX_BLOCKS 1406 */ 1407static ext4_lblk_t ext4_ext_next_leaf_block(struct ext4_ext_path *path) 1408{ 1409 int depth; 1410 1411 BUG_ON(path == NULL); 1412 depth = path->p_depth; 1413 1414 /* zero-tree has no leaf blocks at all */ 1415 if (depth == 0) 1416 return EXT_MAX_BLOCKS; 1417 1418 /* go to index block */ 1419 depth--; 1420 1421 while (depth >= 0) { 1422 if (path[depth].p_idx != 1423 EXT_LAST_INDEX(path[depth].p_hdr)) 1424 return (ext4_lblk_t) 1425 le32_to_cpu(path[depth].p_idx[1].ei_block); 1426 depth--; 1427 } 1428 1429 return EXT_MAX_BLOCKS; 1430} 1431 1432/* 1433 * ext4_ext_correct_indexes: 1434 * if leaf gets modified and modified extent is first in the leaf, 1435 * then we have to correct all indexes above. 1436 * TODO: do we need to correct tree in all cases? 1437 */ 1438static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode, 1439 struct ext4_ext_path *path) 1440{ 1441 struct ext4_extent_header *eh; 1442 int depth = ext_depth(inode); 1443 struct ext4_extent *ex; 1444 __le32 border; 1445 int k, err = 0; 1446 1447 eh = path[depth].p_hdr; 1448 ex = path[depth].p_ext; 1449 1450 if (unlikely(ex == NULL || eh == NULL)) { 1451 EXT4_ERROR_INODE(inode, 1452 "ex %p == NULL or eh %p == NULL", ex, eh); 1453 return -EIO; 1454 } 1455 1456 if (depth == 0) { 1457 /* there is no tree at all */ 1458 return 0; 1459 } 1460 1461 if (ex != EXT_FIRST_EXTENT(eh)) { 1462 /* we correct tree if first leaf got modified only */ 1463 return 0; 1464 } 1465 1466 /* 1467 * TODO: we need correction if border is smaller than current one 1468 */ 1469 k = depth - 1; 1470 border = path[depth].p_ext->ee_block; 1471 err = ext4_ext_get_access(handle, inode, path + k); 1472 if (err) 1473 return err; 1474 path[k].p_idx->ei_block = border; 1475 err = ext4_ext_dirty(handle, inode, path + k); 1476 if (err) 1477 return err; 1478 1479 while (k--) { 1480 /* change all left-side indexes */ 1481 if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr)) 1482 break; 1483 err = ext4_ext_get_access(handle, inode, path + k); 1484 if (err) 1485 break; 1486 path[k].p_idx->ei_block = border; 1487 err = ext4_ext_dirty(handle, inode, path + k); 1488 if (err) 1489 break; 1490 } 1491 1492 return err; 1493} 1494 1495int 1496ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1, 1497 struct ext4_extent *ex2) 1498{ 1499 unsigned short ext1_ee_len, ext2_ee_len, max_len; 1500 1501 /* 1502 * Make sure that either both extents are uninitialized, or 1503 * both are _not_. 1504 */ 1505 if (ext4_ext_is_uninitialized(ex1) ^ ext4_ext_is_uninitialized(ex2)) 1506 return 0; 1507 1508 if (ext4_ext_is_uninitialized(ex1)) 1509 max_len = EXT_UNINIT_MAX_LEN; 1510 else 1511 max_len = EXT_INIT_MAX_LEN; 1512 1513 ext1_ee_len = ext4_ext_get_actual_len(ex1); 1514 ext2_ee_len = ext4_ext_get_actual_len(ex2); 1515 1516 if (le32_to_cpu(ex1->ee_block) + ext1_ee_len != 1517 le32_to_cpu(ex2->ee_block)) 1518 return 0; 1519 1520 /* 1521 * To allow future support for preallocated extents to be added 1522 * as an RO_COMPAT feature, refuse to merge to extents if 1523 * this can result in the top bit of ee_len being set. 1524 */ 1525 if (ext1_ee_len + ext2_ee_len > max_len) 1526 return 0; 1527#ifdef AGGRESSIVE_TEST 1528 if (ext1_ee_len >= 4) 1529 return 0; 1530#endif 1531 1532 if (ext4_ext_pblock(ex1) + ext1_ee_len == ext4_ext_pblock(ex2)) 1533 return 1; 1534 return 0; 1535} 1536 1537/* 1538 * This function tries to merge the "ex" extent to the next extent in the tree. 1539 * It always tries to merge towards right. If you want to merge towards 1540 * left, pass "ex - 1" as argument instead of "ex". 1541 * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns 1542 * 1 if they got merged. 1543 */ 1544static int ext4_ext_try_to_merge_right(struct inode *inode, 1545 struct ext4_ext_path *path, 1546 struct ext4_extent *ex) 1547{ 1548 struct ext4_extent_header *eh; 1549 unsigned int depth, len; 1550 int merge_done = 0; 1551 int uninitialized = 0; 1552 1553 depth = ext_depth(inode); 1554 BUG_ON(path[depth].p_hdr == NULL); 1555 eh = path[depth].p_hdr; 1556 1557 while (ex < EXT_LAST_EXTENT(eh)) { 1558 if (!ext4_can_extents_be_merged(inode, ex, ex + 1)) 1559 break; 1560 /* merge with next extent! */ 1561 if (ext4_ext_is_uninitialized(ex)) 1562 uninitialized = 1; 1563 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex) 1564 + ext4_ext_get_actual_len(ex + 1)); 1565 if (uninitialized) 1566 ext4_ext_mark_uninitialized(ex); 1567 1568 if (ex + 1 < EXT_LAST_EXTENT(eh)) { 1569 len = (EXT_LAST_EXTENT(eh) - ex - 1) 1570 * sizeof(struct ext4_extent); 1571 memmove(ex + 1, ex + 2, len); 1572 } 1573 le16_add_cpu(&eh->eh_entries, -1); 1574 merge_done = 1; 1575 WARN_ON(eh->eh_entries == 0); 1576 if (!eh->eh_entries) 1577 EXT4_ERROR_INODE(inode, "eh->eh_entries = 0!"); 1578 } 1579 1580 return merge_done; 1581} 1582 1583/* 1584 * This function tries to merge the @ex extent to neighbours in the tree. 1585 * return 1 if merge left else 0. 1586 */ 1587static int ext4_ext_try_to_merge(struct inode *inode, 1588 struct ext4_ext_path *path, 1589 struct ext4_extent *ex) { 1590 struct ext4_extent_header *eh; 1591 unsigned int depth; 1592 int merge_done = 0; 1593 int ret = 0; 1594 1595 depth = ext_depth(inode); 1596 BUG_ON(path[depth].p_hdr == NULL); 1597 eh = path[depth].p_hdr; 1598 1599 if (ex > EXT_FIRST_EXTENT(eh)) 1600 merge_done = ext4_ext_try_to_merge_right(inode, path, ex - 1); 1601 1602 if (!merge_done) 1603 ret = ext4_ext_try_to_merge_right(inode, path, ex); 1604 1605 return ret; 1606} 1607 1608/* 1609 * check if a portion of the "newext" extent overlaps with an 1610 * existing extent. 1611 * 1612 * If there is an overlap discovered, it updates the length of the newext 1613 * such that there will be no overlap, and then returns 1. 1614 * If there is no overlap found, it returns 0. 1615 */ 1616static unsigned int ext4_ext_check_overlap(struct ext4_sb_info *sbi, 1617 struct inode *inode, 1618 struct ext4_extent *newext, 1619 struct ext4_ext_path *path) 1620{ 1621 ext4_lblk_t b1, b2; 1622 unsigned int depth, len1; 1623 unsigned int ret = 0; 1624 1625 b1 = le32_to_cpu(newext->ee_block); 1626 len1 = ext4_ext_get_actual_len(newext); 1627 depth = ext_depth(inode); 1628 if (!path[depth].p_ext) 1629 goto out; 1630 b2 = le32_to_cpu(path[depth].p_ext->ee_block); 1631 b2 &= ~(sbi->s_cluster_ratio - 1); 1632 1633 /* 1634 * get the next allocated block if the extent in the path 1635 * is before the requested block(s) 1636 */ 1637 if (b2 < b1) { 1638 b2 = ext4_ext_next_allocated_block(path); 1639 if (b2 == EXT_MAX_BLOCKS) 1640 goto out; 1641 b2 &= ~(sbi->s_cluster_ratio - 1); 1642 } 1643 1644 /* check for wrap through zero on extent logical start block*/ 1645 if (b1 + len1 < b1) { 1646 len1 = EXT_MAX_BLOCKS - b1; 1647 newext->ee_len = cpu_to_le16(len1); 1648 ret = 1; 1649 } 1650 1651 /* check for overlap */ 1652 if (b1 + len1 > b2) { 1653 newext->ee_len = cpu_to_le16(b2 - b1); 1654 ret = 1; 1655 } 1656out: 1657 return ret; 1658} 1659 1660/* 1661 * ext4_ext_insert_extent: 1662 * tries to merge requsted extent into the existing extent or 1663 * inserts requested extent as new one into the tree, 1664 * creating new leaf in the no-space case. 1665 */ 1666int ext4_ext_insert_extent(handle_t *handle, struct inode *inode, 1667 struct ext4_ext_path *path, 1668 struct ext4_extent *newext, int flag) 1669{ 1670 struct ext4_extent_header *eh; 1671 struct ext4_extent *ex, *fex; 1672 struct ext4_extent *nearex; /* nearest extent */ 1673 struct ext4_ext_path *npath = NULL; 1674 int depth, len, err; 1675 ext4_lblk_t next; 1676 unsigned uninitialized = 0; 1677 int flags = 0; 1678 1679 if (unlikely(ext4_ext_get_actual_len(newext) == 0)) { 1680 EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0"); 1681 return -EIO; 1682 } 1683 depth = ext_depth(inode); 1684 ex = path[depth].p_ext; 1685 if (unlikely(path[depth].p_hdr == NULL)) { 1686 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth); 1687 return -EIO; 1688 } 1689 1690 /* try to insert block into found extent and return */ 1691 if (ex && !(flag & EXT4_GET_BLOCKS_PRE_IO) 1692 && ext4_can_extents_be_merged(inode, ex, newext)) { 1693 ext_debug("append [%d]%d block to %d:[%d]%d (from %llu)\n", 1694 ext4_ext_is_uninitialized(newext), 1695 ext4_ext_get_actual_len(newext), 1696 le32_to_cpu(ex->ee_block), 1697 ext4_ext_is_uninitialized(ex), 1698 ext4_ext_get_actual_len(ex), 1699 ext4_ext_pblock(ex)); 1700 err = ext4_ext_get_access(handle, inode, path + depth); 1701 if (err) 1702 return err; 1703 1704 /* 1705 * ext4_can_extents_be_merged should have checked that either 1706 * both extents are uninitialized, or both aren't. Thus we 1707 * need to check only one of them here. 1708 */ 1709 if (ext4_ext_is_uninitialized(ex)) 1710 uninitialized = 1; 1711 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex) 1712 + ext4_ext_get_actual_len(newext)); 1713 if (uninitialized) 1714 ext4_ext_mark_uninitialized(ex); 1715 eh = path[depth].p_hdr; 1716 nearex = ex; 1717 goto merge; 1718 } 1719 1720 depth = ext_depth(inode); 1721 eh = path[depth].p_hdr; 1722 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) 1723 goto has_space; 1724 1725 /* probably next leaf has space for us? */ 1726 fex = EXT_LAST_EXTENT(eh); 1727 next = EXT_MAX_BLOCKS; 1728 if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block)) 1729 next = ext4_ext_next_leaf_block(path); 1730 if (next != EXT_MAX_BLOCKS) { 1731 ext_debug("next leaf block - %d\n", next); 1732 BUG_ON(npath != NULL); 1733 npath = ext4_ext_find_extent(inode, next, NULL); 1734 if (IS_ERR(npath)) 1735 return PTR_ERR(npath); 1736 BUG_ON(npath->p_depth != path->p_depth); 1737 eh = npath[depth].p_hdr; 1738 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) { 1739 ext_debug("next leaf isn't full(%d)\n", 1740 le16_to_cpu(eh->eh_entries)); 1741 path = npath; 1742 goto has_space; 1743 } 1744 ext_debug("next leaf has no free space(%d,%d)\n", 1745 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max)); 1746 } 1747 1748 /* 1749 * There is no free space in the found leaf. 1750 * We're gonna add a new leaf in the tree. 1751 */ 1752 if (flag & EXT4_GET_BLOCKS_PUNCH_OUT_EXT) 1753 flags = EXT4_MB_USE_ROOT_BLOCKS; 1754 err = ext4_ext_create_new_leaf(handle, inode, flags, path, newext); 1755 if (err) 1756 goto cleanup; 1757 depth = ext_depth(inode); 1758 eh = path[depth].p_hdr; 1759 1760has_space: 1761 nearex = path[depth].p_ext; 1762 1763 err = ext4_ext_get_access(handle, inode, path + depth); 1764 if (err) 1765 goto cleanup; 1766 1767 if (!nearex) { 1768 /* there is no extent in this leaf, create first one */ 1769 ext_debug("first extent in the leaf: %d:%llu:[%d]%d\n", 1770 le32_to_cpu(newext->ee_block), 1771 ext4_ext_pblock(newext), 1772 ext4_ext_is_uninitialized(newext), 1773 ext4_ext_get_actual_len(newext)); 1774 nearex = EXT_FIRST_EXTENT(eh); 1775 } else { 1776 if (le32_to_cpu(newext->ee_block) 1777 > le32_to_cpu(nearex->ee_block)) { 1778 /* Insert after */ 1779 ext_debug("insert %d:%llu:[%d]%d %s before: " 1780 "nearest 0x%p\n" 1781 le32_to_cpu(newext->ee_block), 1782 ext4_ext_pblock(newext), 1783 ext4_ext_is_uninitialized(newext), 1784 ext4_ext_get_actual_len(newext), 1785 nearex); 1786 nearex++; 1787 } else { 1788 /* Insert before */ 1789 BUG_ON(newext->ee_block == nearex->ee_block); 1790 ext_debug("insert %d:%llu:[%d]%d %s after: " 1791 "nearest 0x%p\n" 1792 le32_to_cpu(newext->ee_block), 1793 ext4_ext_pblock(newext), 1794 ext4_ext_is_uninitialized(newext), 1795 ext4_ext_get_actual_len(newext), 1796 nearex); 1797 } 1798 len = EXT_LAST_EXTENT(eh) - nearex + 1; 1799 if (len > 0) { 1800 ext_debug("insert %d:%llu:[%d]%d: " 1801 "move %d extents from 0x%p to 0x%p\n", 1802 le32_to_cpu(newext->ee_block), 1803 ext4_ext_pblock(newext), 1804 ext4_ext_is_uninitialized(newext), 1805 ext4_ext_get_actual_len(newext), 1806 len, nearex, nearex + 1); 1807 memmove(nearex + 1, nearex, 1808 len * sizeof(struct ext4_extent)); 1809 } 1810 } 1811 1812 le16_add_cpu(&eh->eh_entries, 1); 1813 path[depth].p_ext = nearex; 1814 nearex->ee_block = newext->ee_block; 1815 ext4_ext_store_pblock(nearex, ext4_ext_pblock(newext)); 1816 nearex->ee_len = newext->ee_len; 1817 1818merge: 1819 /* try to merge extents to the right */ 1820 if (!(flag & EXT4_GET_BLOCKS_PRE_IO)) 1821 ext4_ext_try_to_merge(inode, path, nearex); 1822 1823 /* try to merge extents to the left */ 1824 1825 /* time to correct all indexes above */ 1826 err = ext4_ext_correct_indexes(handle, inode, path); 1827 if (err) 1828 goto cleanup; 1829 1830 err = ext4_ext_dirty(handle, inode, path + depth); 1831 1832cleanup: 1833 if (npath) { 1834 ext4_ext_drop_refs(npath); 1835 kfree(npath); 1836 } 1837 ext4_ext_invalidate_cache(inode); 1838 return err; 1839} 1840 1841static int ext4_ext_walk_space(struct inode *inode, ext4_lblk_t block, 1842 ext4_lblk_t num, ext_prepare_callback func, 1843 void *cbdata) 1844{ 1845 struct ext4_ext_path *path = NULL; 1846 struct ext4_ext_cache cbex; 1847 struct ext4_extent *ex; 1848 ext4_lblk_t next, start = 0, end = 0; 1849 ext4_lblk_t last = block + num; 1850 int depth, exists, err = 0; 1851 1852 BUG_ON(func == NULL); 1853 BUG_ON(inode == NULL); 1854 1855 while (block < last && block != EXT_MAX_BLOCKS) { 1856 num = last - block; 1857 /* find extent for this block */ 1858 down_read(&EXT4_I(inode)->i_data_sem); 1859 path = ext4_ext_find_extent(inode, block, path); 1860 up_read(&EXT4_I(inode)->i_data_sem); 1861 if (IS_ERR(path)) { 1862 err = PTR_ERR(path); 1863 path = NULL; 1864 break; 1865 } 1866 1867 depth = ext_depth(inode); 1868 if (unlikely(path[depth].p_hdr == NULL)) { 1869 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth); 1870 err = -EIO; 1871 break; 1872 } 1873 ex = path[depth].p_ext; 1874 next = ext4_ext_next_allocated_block(path); 1875 1876 exists = 0; 1877 if (!ex) { 1878 /* there is no extent yet, so try to allocate 1879 * all requested space */ 1880 start = block; 1881 end = block + num; 1882 } else if (le32_to_cpu(ex->ee_block) > block) { 1883 /* need to allocate space before found extent */ 1884 start = block; 1885 end = le32_to_cpu(ex->ee_block); 1886 if (block + num < end) 1887 end = block + num; 1888 } else if (block >= le32_to_cpu(ex->ee_block) 1889 + ext4_ext_get_actual_len(ex)) { 1890 /* need to allocate space after found extent */ 1891 start = block; 1892 end = block + num; 1893 if (end >= next) 1894 end = next; 1895 } else if (block >= le32_to_cpu(ex->ee_block)) { 1896 /* 1897 * some part of requested space is covered 1898 * by found extent 1899 */ 1900 start = block; 1901 end = le32_to_cpu(ex->ee_block) 1902 + ext4_ext_get_actual_len(ex); 1903 if (block + num < end) 1904 end = block + num; 1905 exists = 1; 1906 } else { 1907 BUG(); 1908 } 1909 BUG_ON(end <= start); 1910 1911 if (!exists) { 1912 cbex.ec_block = start; 1913 cbex.ec_len = end - start; 1914 cbex.ec_start = 0; 1915 } else { 1916 cbex.ec_block = le32_to_cpu(ex->ee_block); 1917 cbex.ec_len = ext4_ext_get_actual_len(ex); 1918 cbex.ec_start = ext4_ext_pblock(ex); 1919 } 1920 1921 if (unlikely(cbex.ec_len == 0)) { 1922 EXT4_ERROR_INODE(inode, "cbex.ec_len == 0"); 1923 err = -EIO; 1924 break; 1925 } 1926 err = func(inode, next, &cbex, ex, cbdata); 1927 ext4_ext_drop_refs(path); 1928 1929 if (err < 0) 1930 break; 1931 1932 if (err == EXT_REPEAT) 1933 continue; 1934 else if (err == EXT_BREAK) { 1935 err = 0; 1936 break; 1937 } 1938 1939 if (ext_depth(inode) != depth) { 1940 /* depth was changed. we have to realloc path */ 1941 kfree(path); 1942 path = NULL; 1943 } 1944 1945 block = cbex.ec_block + cbex.ec_len; 1946 } 1947 1948 if (path) { 1949 ext4_ext_drop_refs(path); 1950 kfree(path); 1951 } 1952 1953 return err; 1954} 1955 1956static void 1957ext4_ext_put_in_cache(struct inode *inode, ext4_lblk_t block, 1958 __u32 len, ext4_fsblk_t start) 1959{ 1960 struct ext4_ext_cache *cex; 1961 BUG_ON(len == 0); 1962 spin_lock(&EXT4_I(inode)->i_block_reservation_lock); 1963 trace_ext4_ext_put_in_cache(inode, block, len, start); 1964 cex = &EXT4_I(inode)->i_cached_extent; 1965 cex->ec_block = block; 1966 cex->ec_len = len; 1967 cex->ec_start = start; 1968 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock); 1969} 1970 1971/* 1972 * ext4_ext_put_gap_in_cache: 1973 * calculate boundaries of the gap that the requested block fits into 1974 * and cache this gap 1975 */ 1976static void 1977ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path, 1978 ext4_lblk_t block) 1979{ 1980 int depth = ext_depth(inode); 1981 unsigned long len; 1982 ext4_lblk_t lblock; 1983 struct ext4_extent *ex; 1984 1985 ex = path[depth].p_ext; 1986 if (ex == NULL) { 1987 /* there is no extent yet, so gap is [0;-] */ 1988 lblock = 0; 1989 len = EXT_MAX_BLOCKS; 1990 ext_debug("cache gap(whole file):"); 1991 } else if (block < le32_to_cpu(ex->ee_block)) { 1992 lblock = block; 1993 len = le32_to_cpu(ex->ee_block) - block; 1994 ext_debug("cache gap(before): %u [%u:%u]", 1995 block, 1996 le32_to_cpu(ex->ee_block), 1997 ext4_ext_get_actual_len(ex)); 1998 } else if (block >= le32_to_cpu(ex->ee_block) 1999 + ext4_ext_get_actual_len(ex)) { 2000 ext4_lblk_t next; 2001 lblock = le32_to_cpu(ex->ee_block) 2002 + ext4_ext_get_actual_len(ex); 2003 2004 next = ext4_ext_next_allocated_block(path); 2005 ext_debug("cache gap(after): [%u:%u] %u", 2006 le32_to_cpu(ex->ee_block), 2007 ext4_ext_get_actual_len(ex), 2008 block); 2009 BUG_ON(next == lblock); 2010 len = next - lblock; 2011 } else { 2012 lblock = len = 0; 2013 BUG(); 2014 } 2015 2016 ext_debug(" -> %u:%lu\n", lblock, len); 2017 ext4_ext_put_in_cache(inode, lblock, len, 0); 2018} 2019 2020/* 2021 * ext4_ext_check_cache() 2022 * Checks to see if the given block is in the cache. 2023 * If it is, the cached extent is stored in the given 2024 * cache extent pointer. If the cached extent is a hole, 2025 * this routine should be used instead of 2026 * ext4_ext_in_cache if the calling function needs to 2027 * know the size of the hole. 2028 * 2029 * @inode: The files inode 2030 * @block: The block to look for in the cache 2031 * @ex: Pointer where the cached extent will be stored 2032 * if it contains block 2033 * 2034 * Return 0 if cache is invalid; 1 if the cache is valid 2035 */ 2036static int ext4_ext_check_cache(struct inode *inode, ext4_lblk_t block, 2037 struct ext4_ext_cache *ex){ 2038 struct ext4_ext_cache *cex; 2039 struct ext4_sb_info *sbi; 2040 int ret = 0; 2041 2042 /* 2043 * We borrow i_block_reservation_lock to protect i_cached_extent 2044 */ 2045 spin_lock(&EXT4_I(inode)->i_block_reservation_lock); 2046 cex = &EXT4_I(inode)->i_cached_extent; 2047 sbi = EXT4_SB(inode->i_sb); 2048 2049 /* has cache valid data? */ 2050 if (cex->ec_len == 0) 2051 goto errout; 2052 2053 if (in_range(block, cex->ec_block, cex->ec_len)) { 2054 memcpy(ex, cex, sizeof(struct ext4_ext_cache)); 2055 ext_debug("%u cached by %u:%u:%llu\n", 2056 block, 2057 cex->ec_block, cex->ec_len, cex->ec_start); 2058 ret = 1; 2059 } 2060errout: 2061 if (!ret) 2062 sbi->extent_cache_misses++; 2063 else 2064 sbi->extent_cache_hits++; 2065 trace_ext4_ext_in_cache(inode, block, ret); 2066 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock); 2067 return ret; 2068} 2069 2070/* 2071 * ext4_ext_in_cache() 2072 * Checks to see if the given block is in the cache. 2073 * If it is, the cached extent is stored in the given 2074 * extent pointer. 2075 * 2076 * @inode: The files inode 2077 * @block: The block to look for in the cache 2078 * @ex: Pointer where the cached extent will be stored 2079 * if it contains block 2080 * 2081 * Return 0 if cache is invalid; 1 if the cache is valid 2082 */ 2083static int 2084ext4_ext_in_cache(struct inode *inode, ext4_lblk_t block, 2085 struct ext4_extent *ex) 2086{ 2087 struct ext4_ext_cache cex; 2088 int ret = 0; 2089 2090 if (ext4_ext_check_cache(inode, block, &cex)) { 2091 ex->ee_block = cpu_to_le32(cex.ec_block); 2092 ext4_ext_store_pblock(ex, cex.ec_start); 2093 ex->ee_len = cpu_to_le16(cex.ec_len); 2094 ret = 1; 2095 } 2096 2097 return ret; 2098} 2099 2100 2101/* 2102 * ext4_ext_rm_idx: 2103 * removes index from the index block. 2104 */ 2105static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode, 2106 struct ext4_ext_path *path) 2107{ 2108 int err; 2109 ext4_fsblk_t leaf; 2110 2111 /* free index block */ 2112 path--; 2113 leaf = ext4_idx_pblock(path->p_idx); 2114 if (unlikely(path->p_hdr->eh_entries == 0)) { 2115 EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0"); 2116 return -EIO; 2117 } 2118 err = ext4_ext_get_access(handle, inode, path); 2119 if (err) 2120 return err; 2121 2122 if (path->p_idx != EXT_LAST_INDEX(path->p_hdr)) { 2123 int len = EXT_LAST_INDEX(path->p_hdr) - path->p_idx; 2124 len *= sizeof(struct ext4_extent_idx); 2125 memmove(path->p_idx, path->p_idx + 1, len); 2126 } 2127 2128 le16_add_cpu(&path->p_hdr->eh_entries, -1); 2129 err = ext4_ext_dirty(handle, inode, path); 2130 if (err) 2131 return err; 2132 ext_debug("index is empty, remove it, free block %llu\n", leaf); 2133 trace_ext4_ext_rm_idx(inode, leaf); 2134 2135 ext4_free_blocks(handle, inode, NULL, leaf, 1, 2136 EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET); 2137 return err; 2138} 2139 2140/* 2141 * ext4_ext_calc_credits_for_single_extent: 2142 * This routine returns max. credits that needed to insert an extent 2143 * to the extent tree. 2144 * When pass the actual path, the caller should calculate credits 2145 * under i_data_sem. 2146 */ 2147int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks, 2148 struct ext4_ext_path *path) 2149{ 2150 if (path) { 2151 int depth = ext_depth(inode); 2152 int ret = 0; 2153 2154 /* probably there is space in leaf? */ 2155 if (le16_to_cpu(path[depth].p_hdr->eh_entries) 2156 < le16_to_cpu(path[depth].p_hdr->eh_max)) { 2157 2158 /* 2159 * There are some space in the leaf tree, no 2160 * need to account for leaf block credit 2161 * 2162 * bitmaps and block group descriptor blocks 2163 * and other metadata blocks still need to be 2164 * accounted. 2165 */ 2166 /* 1 bitmap, 1 block group descriptor */ 2167 ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb); 2168 return ret; 2169 } 2170 } 2171 2172 return ext4_chunk_trans_blocks(inode, nrblocks); 2173} 2174 2175/* 2176 * How many index/leaf blocks need to change/allocate to modify nrblocks? 2177 * 2178 * if nrblocks are fit in a single extent (chunk flag is 1), then 2179 * in the worse case, each tree level index/leaf need to be changed 2180 * if the tree split due to insert a new extent, then the old tree 2181 * index/leaf need to be updated too 2182 * 2183 * If the nrblocks are discontiguous, they could cause 2184 * the whole tree split more than once, but this is really rare. 2185 */ 2186int ext4_ext_index_trans_blocks(struct inode *inode, int nrblocks, int chunk) 2187{ 2188 int index; 2189 int depth = ext_depth(inode); 2190 2191 if (chunk) 2192 index = depth * 2; 2193 else 2194 index = depth * 3; 2195 2196 return index; 2197} 2198 2199static int ext4_remove_blocks(handle_t *handle, struct inode *inode, 2200 struct ext4_extent *ex, 2201 ext4_fsblk_t *partial_cluster, 2202 ext4_lblk_t from, ext4_lblk_t to) 2203{ 2204 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 2205 unsigned short ee_len = ext4_ext_get_actual_len(ex); 2206 ext4_fsblk_t pblk; 2207 int flags = EXT4_FREE_BLOCKS_FORGET; 2208 2209 if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) 2210 flags |= EXT4_FREE_BLOCKS_METADATA; 2211 /* 2212 * For bigalloc file systems, we never free a partial cluster 2213 * at the beginning of the extent. Instead, we make a note 2214 * that we tried freeing the cluster, and check to see if we 2215 * need to free it on a subsequent call to ext4_remove_blocks, 2216 * or at the end of the ext4_truncate() operation. 2217 */ 2218 flags |= EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER; 2219 2220 trace_ext4_remove_blocks(inode, ex, from, to, *partial_cluster); 2221 /* 2222 * If we have a partial cluster, and it's different from the 2223 * cluster of the last block, we need to explicitly free the 2224 * partial cluster here. 2225 */ 2226 pblk = ext4_ext_pblock(ex) + ee_len - 1; 2227 if (*partial_cluster && (EXT4_B2C(sbi, pblk) != *partial_cluster)) { 2228 ext4_free_blocks(handle, inode, NULL, 2229 EXT4_C2B(sbi, *partial_cluster), 2230 sbi->s_cluster_ratio, flags); 2231 *partial_cluster = 0; 2232 } 2233 2234#ifdef EXTENTS_STATS 2235 { 2236 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 2237 spin_lock(&sbi->s_ext_stats_lock); 2238 sbi->s_ext_blocks += ee_len; 2239 sbi->s_ext_extents++; 2240 if (ee_len < sbi->s_ext_min) 2241 sbi->s_ext_min = ee_len; 2242 if (ee_len > sbi->s_ext_max) 2243 sbi->s_ext_max = ee_len; 2244 if (ext_depth(inode) > sbi->s_depth_max) 2245 sbi->s_depth_max = ext_depth(inode); 2246 spin_unlock(&sbi->s_ext_stats_lock); 2247 } 2248#endif 2249 if (from >= le32_to_cpu(ex->ee_block) 2250 && to == le32_to_cpu(ex->ee_block) + ee_len - 1) { 2251 /* tail removal */ 2252 ext4_lblk_t num; 2253 2254 num = le32_to_cpu(ex->ee_block) + ee_len - from; 2255 pblk = ext4_ext_pblock(ex) + ee_len - num; 2256 ext_debug("free last %u blocks starting %llu\n", num, pblk); 2257 ext4_free_blocks(handle, inode, NULL, pblk, num, flags); 2258 /* 2259 * If the block range to be freed didn't start at the 2260 * beginning of a cluster, and we removed the entire 2261 * extent, save the partial cluster here, since we 2262 * might need to delete if we determine that the 2263 * truncate operation has removed all of the blocks in 2264 * the cluster. 2265 */ 2266 if (pblk & (sbi->s_cluster_ratio - 1) && 2267 (ee_len == num)) 2268 *partial_cluster = EXT4_B2C(sbi, pblk); 2269 else 2270 *partial_cluster = 0; 2271 } else if (from == le32_to_cpu(ex->ee_block) 2272 && to <= le32_to_cpu(ex->ee_block) + ee_len - 1) { 2273 /* head removal */ 2274 ext4_lblk_t num; 2275 ext4_fsblk_t start; 2276 2277 num = to - from; 2278 start = ext4_ext_pblock(ex); 2279 2280 ext_debug("free first %u blocks starting %llu\n", num, start); 2281 ext4_free_blocks(handle, inode, NULL, start, num, flags); 2282 2283 } else { 2284 printk(KERN_INFO "strange request: removal(2) " 2285 "%u-%u from %u:%u\n", 2286 from, to, le32_to_cpu(ex->ee_block), ee_len); 2287 } 2288 return 0; 2289} 2290 2291 2292/* 2293 * ext4_ext_rm_leaf() Removes the extents associated with the 2294 * blocks appearing between "start" and "end", and splits the extents 2295 * if "start" and "end" appear in the same extent 2296 * 2297 * @handle: The journal handle 2298 * @inode: The files inode 2299 * @path: The path to the leaf 2300 * @start: The first block to remove 2301 * @end: The last block to remove 2302 */ 2303static int 2304ext4_ext_rm_leaf(handle_t *handle, struct inode *inode, 2305 struct ext4_ext_path *path, ext4_fsblk_t *partial_cluster, 2306 ext4_lblk_t start, ext4_lblk_t end) 2307{ 2308 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 2309 int err = 0, correct_index = 0; 2310 int depth = ext_depth(inode), credits; 2311 struct ext4_extent_header *eh; 2312 ext4_lblk_t a, b; 2313 unsigned num; 2314 ext4_lblk_t ex_ee_block; 2315 unsigned short ex_ee_len; 2316 unsigned uninitialized = 0; 2317 struct ext4_extent *ex; 2318 2319 /* the header must be checked already in ext4_ext_remove_space() */ 2320 ext_debug("truncate since %u in leaf\n", start); 2321 if (!path[depth].p_hdr) 2322 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh); 2323 eh = path[depth].p_hdr; 2324 if (unlikely(path[depth].p_hdr == NULL)) { 2325 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth); 2326 return -EIO; 2327 } 2328 /* find where to start removing */ 2329 ex = EXT_LAST_EXTENT(eh); 2330 2331 ex_ee_block = le32_to_cpu(ex->ee_block); 2332 ex_ee_len = ext4_ext_get_actual_len(ex); 2333 2334 trace_ext4_ext_rm_leaf(inode, start, ex, *partial_cluster); 2335 2336 while (ex >= EXT_FIRST_EXTENT(eh) && 2337 ex_ee_block + ex_ee_len > start) { 2338 2339 if (ext4_ext_is_uninitialized(ex)) 2340 uninitialized = 1; 2341 else 2342 uninitialized = 0; 2343 2344 ext_debug("remove ext %u:[%d]%d\n", ex_ee_block, 2345 uninitialized, ex_ee_len); 2346 path[depth].p_ext = ex; 2347 2348 a = ex_ee_block > start ? ex_ee_block : start; 2349 b = ex_ee_block+ex_ee_len - 1 < end ? 2350 ex_ee_block+ex_ee_len - 1 : end; 2351 2352 ext_debug(" border %u:%u\n", a, b); 2353 2354 /* If this extent is beyond the end of the hole, skip it */ 2355 if (end <= ex_ee_block) { 2356 ex--; 2357 ex_ee_block = le32_to_cpu(ex->ee_block); 2358 ex_ee_len = ext4_ext_get_actual_len(ex); 2359 continue; 2360 } else if (b != ex_ee_block + ex_ee_len - 1) { 2361 EXT4_ERROR_INODE(inode," bad truncate %u:%u\n", 2362 start, end); 2363 err = -EIO; 2364 goto out; 2365 } else if (a != ex_ee_block) { 2366 /* remove tail of the extent */ 2367 num = a - ex_ee_block; 2368 } else { 2369 /* remove whole extent: excellent! */ 2370 num = 0; 2371 } 2372 /* 2373 * 3 for leaf, sb, and inode plus 2 (bmap and group 2374 * descriptor) for each block group; assume two block 2375 * groups plus ex_ee_len/blocks_per_block_group for 2376 * the worst case 2377 */ 2378 credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb)); 2379 if (ex == EXT_FIRST_EXTENT(eh)) { 2380 correct_index = 1; 2381 credits += (ext_depth(inode)) + 1; 2382 } 2383 credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb); 2384 2385 err = ext4_ext_truncate_extend_restart(handle, inode, credits); 2386 if (err) 2387 goto out; 2388 2389 err = ext4_ext_get_access(handle, inode, path + depth); 2390 if (err) 2391 goto out; 2392 2393 err = ext4_remove_blocks(handle, inode, ex, partial_cluster, 2394 a, b); 2395 if (err) 2396 goto out; 2397 2398 if (num == 0) 2399 /* this extent is removed; mark slot entirely unused */ 2400 ext4_ext_store_pblock(ex, 0); 2401 2402 ex->ee_len = cpu_to_le16(num); 2403 /* 2404 * Do not mark uninitialized if all the blocks in the 2405 * extent have been removed. 2406 */ 2407 if (uninitialized && num) 2408 ext4_ext_mark_uninitialized(ex); 2409 /* 2410 * If the extent was completely released, 2411 * we need to remove it from the leaf 2412 */ 2413 if (num == 0) { 2414 if (end != EXT_MAX_BLOCKS - 1) { 2415 /* 2416 * For hole punching, we need to scoot all the 2417 * extents up when an extent is removed so that 2418 * we dont have blank extents in the middle 2419 */ 2420 memmove(ex, ex+1, (EXT_LAST_EXTENT(eh) - ex) * 2421 sizeof(struct ext4_extent)); 2422 2423 /* Now get rid of the one at the end */ 2424 memset(EXT_LAST_EXTENT(eh), 0, 2425 sizeof(struct ext4_extent)); 2426 } 2427 le16_add_cpu(&eh->eh_entries, -1); 2428 } else 2429 *partial_cluster = 0; 2430 2431 err = ext4_ext_dirty(handle, inode, path + depth); 2432 if (err) 2433 goto out; 2434 2435 ext_debug("new extent: %u:%u:%llu\n", block, num, 2436 ext4_ext_pblock(ex)); 2437 ex--; 2438 ex_ee_block = le32_to_cpu(ex->ee_block); 2439 ex_ee_len = ext4_ext_get_actual_len(ex); 2440 } 2441 2442 if (correct_index && eh->eh_entries) 2443 err = ext4_ext_correct_indexes(handle, inode, path); 2444 2445 /* 2446 * If there is still a entry in the leaf node, check to see if 2447 * it references the partial cluster. This is the only place 2448 * where it could; if it doesn't, we can free the cluster. 2449 */ 2450 if (*partial_cluster && ex >= EXT_FIRST_EXTENT(eh) && 2451 (EXT4_B2C(sbi, ext4_ext_pblock(ex) + ex_ee_len - 1) != 2452 *partial_cluster)) { 2453 int flags = EXT4_FREE_BLOCKS_FORGET; 2454 2455 if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) 2456 flags |= EXT4_FREE_BLOCKS_METADATA; 2457 2458 ext4_free_blocks(handle, inode, NULL, 2459 EXT4_C2B(sbi, *partial_cluster), 2460 sbi->s_cluster_ratio, flags); 2461 *partial_cluster = 0; 2462 } 2463 2464 /* if this leaf is free, then we should 2465 * remove it from index block above */ 2466 if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL) 2467 err = ext4_ext_rm_idx(handle, inode, path + depth); 2468 2469out: 2470 return err; 2471} 2472 2473/* 2474 * ext4_ext_more_to_rm: 2475 * returns 1 if current index has to be freed (even partial) 2476 */ 2477static int 2478ext4_ext_more_to_rm(struct ext4_ext_path *path) 2479{ 2480 BUG_ON(path->p_idx == NULL); 2481 2482 if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr)) 2483 return 0; 2484 2485 /* 2486 * if truncate on deeper level happened, it wasn't partial, 2487 * so we have to consider current index for truncation 2488 */ 2489 if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block) 2490 return 0; 2491 return 1; 2492} 2493 2494static int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start) 2495{ 2496 struct super_block *sb = inode->i_sb; 2497 int depth = ext_depth(inode); 2498 struct ext4_ext_path *path; 2499 ext4_fsblk_t partial_cluster = 0; 2500 handle_t *handle; 2501 int i, err; 2502 2503 ext_debug("truncate since %u\n", start); 2504 2505 /* probably first extent we're gonna free will be last in block */ 2506 handle = ext4_journal_start(inode, depth + 1); 2507 if (IS_ERR(handle)) 2508 return PTR_ERR(handle); 2509 2510again: 2511 ext4_ext_invalidate_cache(inode); 2512 2513 trace_ext4_ext_remove_space(inode, start, depth); 2514 2515 /* 2516 * We start scanning from right side, freeing all the blocks 2517 * after i_size and walking into the tree depth-wise. 2518 */ 2519 depth = ext_depth(inode); 2520 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1), GFP_NOFS); 2521 if (path == NULL) { 2522 ext4_journal_stop(handle); 2523 return -ENOMEM; 2524 } 2525 path[0].p_depth = depth; 2526 path[0].p_hdr = ext_inode_hdr(inode); 2527 if (ext4_ext_check(inode, path[0].p_hdr, depth)) { 2528 err = -EIO; 2529 goto out; 2530 } 2531 i = err = 0; 2532 2533 while (i >= 0 && err == 0) { 2534 if (i == depth) { 2535 /* this is leaf block */ 2536 err = ext4_ext_rm_leaf(handle, inode, path, 2537 &partial_cluster, start, 2538 EXT_MAX_BLOCKS - 1); 2539 /* root level has p_bh == NULL, brelse() eats this */ 2540 brelse(path[i].p_bh); 2541 path[i].p_bh = NULL; 2542 i--; 2543 continue; 2544 } 2545 2546 /* this is index block */ 2547 if (!path[i].p_hdr) { 2548 ext_debug("initialize header\n"); 2549 path[i].p_hdr = ext_block_hdr(path[i].p_bh); 2550 } 2551 2552 if (!path[i].p_idx) { 2553 /* this level hasn't been touched yet */ 2554 path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr); 2555 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1; 2556 ext_debug("init index ptr: hdr 0x%p, num %d\n", 2557 path[i].p_hdr, 2558 le16_to_cpu(path[i].p_hdr->eh_entries)); 2559 } else { 2560 /* we were already here, see at next index */ 2561 path[i].p_idx--; 2562 } 2563 2564 ext_debug("level %d - index, first 0x%p, cur 0x%p\n", 2565 i, EXT_FIRST_INDEX(path[i].p_hdr), 2566 path[i].p_idx); 2567 if (ext4_ext_more_to_rm(path + i)) { 2568 struct buffer_head *bh; 2569 /* go to the next level */ 2570 ext_debug("move to level %d (block %llu)\n", 2571 i + 1, ext4_idx_pblock(path[i].p_idx)); 2572 memset(path + i + 1, 0, sizeof(*path)); 2573 bh = sb_bread(sb, ext4_idx_pblock(path[i].p_idx)); 2574 if (!bh) { 2575 /* should we reset i_size? */ 2576 err = -EIO; 2577 break; 2578 } 2579 if (WARN_ON(i + 1 > depth)) { 2580 err = -EIO; 2581 break; 2582 } 2583 if (ext4_ext_check(inode, ext_block_hdr(bh), 2584 depth - i - 1)) { 2585 err = -EIO; 2586 break; 2587 } 2588 path[i + 1].p_bh = bh; 2589 2590 /* save actual number of indexes since this 2591 * number is changed at the next iteration */ 2592 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries); 2593 i++; 2594 } else { 2595 /* we finished processing this index, go up */ 2596 if (path[i].p_hdr->eh_entries == 0 && i > 0) { 2597 /* index is empty, remove it; 2598 * handle must be already prepared by the 2599 * truncatei_leaf() */ 2600 err = ext4_ext_rm_idx(handle, inode, path + i); 2601 } 2602 /* root level has p_bh == NULL, brelse() eats this */ 2603 brelse(path[i].p_bh); 2604 path[i].p_bh = NULL; 2605 i--; 2606 ext_debug("return to level %d\n", i); 2607 } 2608 } 2609 2610 trace_ext4_ext_remove_space_done(inode, start, depth, partial_cluster, 2611 path->p_hdr->eh_entries); 2612 2613 /* If we still have something in the partial cluster and we have removed 2614 * even the first extent, then we should free the blocks in the partial 2615 * cluster as well. */ 2616 if (partial_cluster && path->p_hdr->eh_entries == 0) { 2617 int flags = EXT4_FREE_BLOCKS_FORGET; 2618 2619 if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) 2620 flags |= EXT4_FREE_BLOCKS_METADATA; 2621 2622 ext4_free_blocks(handle, inode, NULL, 2623 EXT4_C2B(EXT4_SB(sb), partial_cluster), 2624 EXT4_SB(sb)->s_cluster_ratio, flags); 2625 partial_cluster = 0; 2626 } 2627 2628 /* TODO: flexible tree reduction should be here */ 2629 if (path->p_hdr->eh_entries == 0) { 2630 /* 2631 * truncate to zero freed all the tree, 2632 * so we need to correct eh_depth 2633 */ 2634 err = ext4_ext_get_access(handle, inode, path); 2635 if (err == 0) { 2636 ext_inode_hdr(inode)->eh_depth = 0; 2637 ext_inode_hdr(inode)->eh_max = 2638 cpu_to_le16(ext4_ext_space_root(inode, 0)); 2639 err = ext4_ext_dirty(handle, inode, path); 2640 } 2641 } 2642out: 2643 ext4_ext_drop_refs(path); 2644 kfree(path); 2645 if (err == -EAGAIN) 2646 goto again; 2647 ext4_journal_stop(handle); 2648 2649 return err; 2650} 2651 2652/* 2653 * called at mount time 2654 */ 2655void ext4_ext_init(struct super_block *sb) 2656{ 2657 /* 2658 * possible initialization would be here 2659 */ 2660 2661 if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) { 2662#if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS) 2663 printk(KERN_INFO "EXT4-fs: file extents enabled"); 2664#ifdef AGGRESSIVE_TEST 2665 printk(", aggressive tests"); 2666#endif 2667#ifdef CHECK_BINSEARCH 2668 printk(", check binsearch"); 2669#endif 2670#ifdef EXTENTS_STATS 2671 printk(", stats"); 2672#endif 2673 printk("\n"); 2674#endif 2675#ifdef EXTENTS_STATS 2676 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock); 2677 EXT4_SB(sb)->s_ext_min = 1 << 30; 2678 EXT4_SB(sb)->s_ext_max = 0; 2679#endif 2680 } 2681} 2682 2683/* 2684 * called at umount time 2685 */ 2686void ext4_ext_release(struct super_block *sb) 2687{ 2688 if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) 2689 return; 2690 2691#ifdef EXTENTS_STATS 2692 if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) { 2693 struct ext4_sb_info *sbi = EXT4_SB(sb); 2694 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n", 2695 sbi->s_ext_blocks, sbi->s_ext_extents, 2696 sbi->s_ext_blocks / sbi->s_ext_extents); 2697 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n", 2698 sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max); 2699 } 2700#endif 2701} 2702 2703/* FIXME!! we need to try to merge to left or right after zero-out */ 2704static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex) 2705{ 2706 ext4_fsblk_t ee_pblock; 2707 unsigned int ee_len; 2708 int ret; 2709 2710 ee_len = ext4_ext_get_actual_len(ex); 2711 ee_pblock = ext4_ext_pblock(ex); 2712 2713 ret = sb_issue_zeroout(inode->i_sb, ee_pblock, ee_len, GFP_NOFS); 2714 if (ret > 0) 2715 ret = 0; 2716 2717 return ret; 2718} 2719 2720/* 2721 * used by extent splitting. 2722 */ 2723#define EXT4_EXT_MAY_ZEROOUT 0x1 /* safe to zeroout if split fails \ 2724 due to ENOSPC */ 2725#define EXT4_EXT_MARK_UNINIT1 0x2 /* mark first half uninitialized */ 2726#define EXT4_EXT_MARK_UNINIT2 0x4 /* mark second half uninitialized */ 2727 2728/* 2729 * ext4_split_extent_at() splits an extent at given block. 2730 * 2731 * @handle: the journal handle 2732 * @inode: the file inode 2733 * @path: the path to the extent 2734 * @split: the logical block where the extent is splitted. 2735 * @split_flags: indicates if the extent could be zeroout if split fails, and 2736 * the states(init or uninit) of new extents. 2737 * @flags: flags used to insert new extent to extent tree. 2738 * 2739 * 2740 * Splits extent [a, b] into two extents [a, @split) and [@split, b], states 2741 * of which are deterimined by split_flag. 2742 * 2743 * There are two cases: 2744 * a> the extent are splitted into two extent. 2745 * b> split is not needed, and just mark the extent. 2746 * 2747 * return 0 on success. 2748 */ 2749static int ext4_split_extent_at(handle_t *handle, 2750 struct inode *inode, 2751 struct ext4_ext_path *path, 2752 ext4_lblk_t split, 2753 int split_flag, 2754 int flags) 2755{ 2756 ext4_fsblk_t newblock; 2757 ext4_lblk_t ee_block; 2758 struct ext4_extent *ex, newex, orig_ex; 2759 struct ext4_extent *ex2 = NULL; 2760 unsigned int ee_len, depth; 2761 int err = 0; 2762 2763 ext_debug("ext4_split_extents_at: inode %lu, logical" 2764 "block %llu\n", inode->i_ino, (unsigned long long)split); 2765 2766 ext4_ext_show_leaf(inode, path); 2767 2768 depth = ext_depth(inode); 2769 ex = path[depth].p_ext; 2770 ee_block = le32_to_cpu(ex->ee_block); 2771 ee_len = ext4_ext_get_actual_len(ex); 2772 newblock = split - ee_block + ext4_ext_pblock(ex); 2773 2774 BUG_ON(split < ee_block || split >= (ee_block + ee_len)); 2775 2776 err = ext4_ext_get_access(handle, inode, path + depth); 2777 if (err) 2778 goto out; 2779 2780 if (split == ee_block) { 2781 /* 2782 * case b: block @split is the block that the extent begins with 2783 * then we just change the state of the extent, and splitting 2784 * is not needed. 2785 */ 2786 if (split_flag & EXT4_EXT_MARK_UNINIT2) 2787 ext4_ext_mark_uninitialized(ex); 2788 else 2789 ext4_ext_mark_initialized(ex); 2790 2791 if (!(flags & EXT4_GET_BLOCKS_PRE_IO)) 2792 ext4_ext_try_to_merge(inode, path, ex); 2793 2794 err = ext4_ext_dirty(handle, inode, path + depth); 2795 goto out; 2796 } 2797 2798 /* case a */ 2799 memcpy(&orig_ex, ex, sizeof(orig_ex)); 2800 ex->ee_len = cpu_to_le16(split - ee_block); 2801 if (split_flag & EXT4_EXT_MARK_UNINIT1) 2802 ext4_ext_mark_uninitialized(ex); 2803 2804 /* 2805 * path may lead to new leaf, not to original leaf any more 2806 * after ext4_ext_insert_extent() returns, 2807 */ 2808 err = ext4_ext_dirty(handle, inode, path + depth); 2809 if (err) 2810 goto fix_extent_len; 2811 2812 ex2 = &newex; 2813 ex2->ee_block = cpu_to_le32(split); 2814 ex2->ee_len = cpu_to_le16(ee_len - (split - ee_block)); 2815 ext4_ext_store_pblock(ex2, newblock); 2816 if (split_flag & EXT4_EXT_MARK_UNINIT2) 2817 ext4_ext_mark_uninitialized(ex2); 2818 2819 err = ext4_ext_insert_extent(handle, inode, path, &newex, flags); 2820 if (err == -ENOSPC && (EXT4_EXT_MAY_ZEROOUT & split_flag)) { 2821 err = ext4_ext_zeroout(inode, &orig_ex); 2822 if (err) 2823 goto fix_extent_len; 2824 /* update the extent length and mark as initialized */ 2825 ex->ee_len = cpu_to_le32(ee_len); 2826 ext4_ext_try_to_merge(inode, path, ex); 2827 err = ext4_ext_dirty(handle, inode, path + depth); 2828 goto out; 2829 } else if (err) 2830 goto fix_extent_len; 2831 2832out: 2833 ext4_ext_show_leaf(inode, path); 2834 return err; 2835 2836fix_extent_len: 2837 ex->ee_len = orig_ex.ee_len; 2838 ext4_ext_dirty(handle, inode, path + depth); 2839 return err; 2840} 2841 2842/* 2843 * ext4_split_extents() splits an extent and mark extent which is covered 2844 * by @map as split_flags indicates 2845 * 2846 * It may result in splitting the extent into multiple extents (upto three) 2847 * There are three possibilities: 2848 * a> There is no split required 2849 * b> Splits in two extents: Split is happening at either end of the extent 2850 * c> Splits in three extents: Somone is splitting in middle of the extent 2851 * 2852 */ 2853static int ext4_split_extent(handle_t *handle, 2854 struct inode *inode, 2855 struct ext4_ext_path *path, 2856 struct ext4_map_blocks *map, 2857 int split_flag, 2858 int flags) 2859{ 2860 ext4_lblk_t ee_block; 2861 struct ext4_extent *ex; 2862 unsigned int ee_len, depth; 2863 int err = 0; 2864 int uninitialized; 2865 int split_flag1, flags1; 2866 2867 depth = ext_depth(inode); 2868 ex = path[depth].p_ext; 2869 ee_block = le32_to_cpu(ex->ee_block); 2870 ee_len = ext4_ext_get_actual_len(ex); 2871 uninitialized = ext4_ext_is_uninitialized(ex); 2872 2873 if (map->m_lblk + map->m_len < ee_block + ee_len) { 2874 split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT ? 2875 EXT4_EXT_MAY_ZEROOUT : 0; 2876 flags1 = flags | EXT4_GET_BLOCKS_PRE_IO; 2877 if (uninitialized) 2878 split_flag1 |= EXT4_EXT_MARK_UNINIT1 | 2879 EXT4_EXT_MARK_UNINIT2; 2880 err = ext4_split_extent_at(handle, inode, path, 2881 map->m_lblk + map->m_len, split_flag1, flags1); 2882 if (err) 2883 goto out; 2884 } 2885 2886 ext4_ext_drop_refs(path); 2887 path = ext4_ext_find_extent(inode, map->m_lblk, path); 2888 if (IS_ERR(path)) 2889 return PTR_ERR(path); 2890 2891 if (map->m_lblk >= ee_block) { 2892 split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT ? 2893 EXT4_EXT_MAY_ZEROOUT : 0; 2894 if (uninitialized) 2895 split_flag1 |= EXT4_EXT_MARK_UNINIT1; 2896 if (split_flag & EXT4_EXT_MARK_UNINIT2) 2897 split_flag1 |= EXT4_EXT_MARK_UNINIT2; 2898 err = ext4_split_extent_at(handle, inode, path, 2899 map->m_lblk, split_flag1, flags); 2900 if (err) 2901 goto out; 2902 } 2903 2904 ext4_ext_show_leaf(inode, path); 2905out: 2906 return err ? err : map->m_len; 2907} 2908 2909#define EXT4_EXT_ZERO_LEN 7 2910/* 2911 * This function is called by ext4_ext_map_blocks() if someone tries to write 2912 * to an uninitialized extent. It may result in splitting the uninitialized 2913 * extent into multiple extents (up to three - one initialized and two 2914 * uninitialized). 2915 * There are three possibilities: 2916 * a> There is no split required: Entire extent should be initialized 2917 * b> Splits in two extents: Write is happening at either end of the extent 2918 * c> Splits in three extents: Somone is writing in middle of the extent 2919 * 2920 * Pre-conditions: 2921 * - The extent pointed to by 'path' is uninitialized. 2922 * - The extent pointed to by 'path' contains a superset 2923 * of the logical span [map->m_lblk, map->m_lblk + map->m_len). 2924 * 2925 * Post-conditions on success: 2926 * - the returned value is the number of blocks beyond map->l_lblk 2927 * that are allocated and initialized. 2928 * It is guaranteed to be >= map->m_len. 2929 */ 2930static int ext4_ext_convert_to_initialized(handle_t *handle, 2931 struct inode *inode, 2932 struct ext4_map_blocks *map, 2933 struct ext4_ext_path *path) 2934{ 2935 struct ext4_extent_header *eh; 2936 struct ext4_map_blocks split_map; 2937 struct ext4_extent zero_ex; 2938 struct ext4_extent *ex; 2939 ext4_lblk_t ee_block, eof_block; 2940 unsigned int ee_len, depth; 2941 int allocated; 2942 int err = 0; 2943 int split_flag = 0; 2944 2945 ext_debug("ext4_ext_convert_to_initialized: inode %lu, logical" 2946 "block %llu, max_blocks %u\n", inode->i_ino, 2947 (unsigned long long)map->m_lblk, map->m_len); 2948 2949 eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >> 2950 inode->i_sb->s_blocksize_bits; 2951 if (eof_block < map->m_lblk + map->m_len) 2952 eof_block = map->m_lblk + map->m_len; 2953 2954 depth = ext_depth(inode); 2955 eh = path[depth].p_hdr; 2956 ex = path[depth].p_ext; 2957 ee_block = le32_to_cpu(ex->ee_block); 2958 ee_len = ext4_ext_get_actual_len(ex); 2959 allocated = ee_len - (map->m_lblk - ee_block); 2960 2961 trace_ext4_ext_convert_to_initialized_enter(inode, map, ex); 2962 2963 /* Pre-conditions */ 2964 BUG_ON(!ext4_ext_is_uninitialized(ex)); 2965 BUG_ON(!in_range(map->m_lblk, ee_block, ee_len)); 2966 BUG_ON(map->m_lblk + map->m_len > ee_block + ee_len); 2967 2968 /* 2969 * Attempt to transfer newly initialized blocks from the currently 2970 * uninitialized extent to its left neighbor. This is much cheaper 2971 * than an insertion followed by a merge as those involve costly 2972 * memmove() calls. This is the common case in steady state for 2973 * workloads doing fallocate(FALLOC_FL_KEEP_SIZE) followed by append 2974 * writes. 2975 * 2976 * Limitations of the current logic: 2977 * - L1: we only deal with writes at the start of the extent. 2978 * The approach could be extended to writes at the end 2979 * of the extent but this scenario was deemed less common. 2980 * - L2: we do not deal with writes covering the whole extent. 2981 * This would require removing the extent if the transfer 2982 * is possible. 2983 * - L3: we only attempt to merge with an extent stored in the 2984 * same extent tree node. 2985 */ 2986 if ((map->m_lblk == ee_block) && /*L1*/ 2987 (map->m_len < ee_len) && /*L2*/ 2988 (ex > EXT_FIRST_EXTENT(eh))) { /*L3*/ 2989 struct ext4_extent *prev_ex; 2990 ext4_lblk_t prev_lblk; 2991 ext4_fsblk_t prev_pblk, ee_pblk; 2992 unsigned int prev_len, write_len; 2993 2994 prev_ex = ex - 1; 2995 prev_lblk = le32_to_cpu(prev_ex->ee_block); 2996 prev_len = ext4_ext_get_actual_len(prev_ex); 2997 prev_pblk = ext4_ext_pblock(prev_ex); 2998 ee_pblk = ext4_ext_pblock(ex); 2999 write_len = map->m_len; 3000 3001 /* 3002 * A transfer of blocks from 'ex' to 'prev_ex' is allowed 3003 * upon those conditions: 3004 * - C1: prev_ex is initialized, 3005 * - C2: prev_ex is logically abutting ex, 3006 * - C3: prev_ex is physically abutting ex, 3007 * - C4: prev_ex can receive the additional blocks without 3008 * overflowing the (initialized) length limit. 3009 */ 3010 if ((!ext4_ext_is_uninitialized(prev_ex)) && /*C1*/ 3011 ((prev_lblk + prev_len) == ee_block) && /*C2*/ 3012 ((prev_pblk + prev_len) == ee_pblk) && /*C3*/ 3013 (prev_len < (EXT_INIT_MAX_LEN - write_len))) { /*C4*/ 3014 err = ext4_ext_get_access(handle, inode, path + depth); 3015 if (err) 3016 goto out; 3017 3018 trace_ext4_ext_convert_to_initialized_fastpath(inode, 3019 map, ex, prev_ex); 3020 3021 /* Shift the start of ex by 'write_len' blocks */ 3022 ex->ee_block = cpu_to_le32(ee_block + write_len); 3023 ext4_ext_store_pblock(ex, ee_pblk + write_len); 3024 ex->ee_len = cpu_to_le16(ee_len - write_len); 3025 ext4_ext_mark_uninitialized(ex); /* Restore the flag */ 3026 3027 /* Extend prev_ex by 'write_len' blocks */ 3028 prev_ex->ee_len = cpu_to_le16(prev_len + write_len); 3029 3030 /* Mark the block containing both extents as dirty */ 3031 ext4_ext_dirty(handle, inode, path + depth); 3032 3033 /* Update path to point to the right extent */ 3034 path[depth].p_ext = prev_ex; 3035 3036 /* Result: number of initialized blocks past m_lblk */ 3037 allocated = write_len; 3038 goto out; 3039 } 3040 } 3041 3042 WARN_ON(map->m_lblk < ee_block); 3043 /* 3044 * It is safe to convert extent to initialized via explicit 3045 * zeroout only if extent is fully insde i_size or new_size. 3046 */ 3047 split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0; 3048 3049 /* If extent has less than 2*EXT4_EXT_ZERO_LEN zerout directly */ 3050 if (ee_len <= 2*EXT4_EXT_ZERO_LEN && 3051 (EXT4_EXT_MAY_ZEROOUT & split_flag)) { 3052 err = ext4_ext_zeroout(inode, ex); 3053 if (err) 3054 goto out; 3055 3056 err = ext4_ext_get_access(handle, inode, path + depth); 3057 if (err) 3058 goto out; 3059 ext4_ext_mark_initialized(ex); 3060 ext4_ext_try_to_merge(inode, path, ex); 3061 err = ext4_ext_dirty(handle, inode, path + depth); 3062 goto out; 3063 } 3064 3065 /* 3066 * four cases: 3067 * 1. split the extent into three extents. 3068 * 2. split the extent into two extents, zeroout the first half. 3069 * 3. split the extent into two extents, zeroout the second half. 3070 * 4. split the extent into two extents with out zeroout. 3071 */ 3072 split_map.m_lblk = map->m_lblk; 3073 split_map.m_len = map->m_len; 3074 3075 if (allocated > map->m_len) { 3076 if (allocated <= EXT4_EXT_ZERO_LEN && 3077 (EXT4_EXT_MAY_ZEROOUT & split_flag)) { 3078 /* case 3 */ 3079 zero_ex.ee_block = 3080 cpu_to_le32(map->m_lblk); 3081 zero_ex.ee_len = cpu_to_le16(allocated); 3082 ext4_ext_store_pblock(&zero_ex, 3083 ext4_ext_pblock(ex) + map->m_lblk - ee_block); 3084 err = ext4_ext_zeroout(inode, &zero_ex); 3085 if (err) 3086 goto out; 3087 split_map.m_lblk = map->m_lblk; 3088 split_map.m_len = allocated; 3089 } else if ((map->m_lblk - ee_block + map->m_len < 3090 EXT4_EXT_ZERO_LEN) && 3091 (EXT4_EXT_MAY_ZEROOUT & split_flag)) { 3092 /* case 2 */ 3093 if (map->m_lblk != ee_block) { 3094 zero_ex.ee_block = ex->ee_block; 3095 zero_ex.ee_len = cpu_to_le16(map->m_lblk - 3096 ee_block); 3097 ext4_ext_store_pblock(&zero_ex, 3098 ext4_ext_pblock(ex)); 3099 err = ext4_ext_zeroout(inode, &zero_ex); 3100 if (err) 3101 goto out; 3102 } 3103 3104 split_map.m_lblk = ee_block; 3105 split_map.m_len = map->m_lblk - ee_block + map->m_len; 3106 allocated = map->m_len; 3107 } 3108 } 3109 3110 allocated = ext4_split_extent(handle, inode, path, 3111 &split_map, split_flag, 0); 3112 if (allocated < 0) 3113 err = allocated; 3114 3115out: 3116 return err ? err : allocated; 3117} 3118 3119/* 3120 * This function is called by ext4_ext_map_blocks() from 3121 * ext4_get_blocks_dio_write() when DIO to write 3122 * to an uninitialized extent. 3123 * 3124 * Writing to an uninitialized extent may result in splitting the uninitialized 3125 * extent into multiple /initialized uninitialized extents (up to three) 3126 * There are three possibilities: 3127 * a> There is no split required: Entire extent should be uninitialized 3128 * b> Splits in two extents: Write is happening at either end of the extent 3129 * c> Splits in three extents: Somone is writing in middle of the extent 3130 * 3131 * One of more index blocks maybe needed if the extent tree grow after 3132 * the uninitialized extent split. To prevent ENOSPC occur at the IO 3133 * complete, we need to split the uninitialized extent before DIO submit 3134 * the IO. The uninitialized extent called at this time will be split 3135 * into three uninitialized extent(at most). After IO complete, the part 3136 * being filled will be convert to initialized by the end_io callback function 3137 * via ext4_convert_unwritten_extents(). 3138 * 3139 * Returns the size of uninitialized extent to be written on success. 3140 */ 3141static int ext4_split_unwritten_extents(handle_t *handle, 3142 struct inode *inode, 3143 struct ext4_map_blocks *map, 3144 struct ext4_ext_path *path, 3145 int flags) 3146{ 3147 ext4_lblk_t eof_block; 3148 ext4_lblk_t ee_block; 3149 struct ext4_extent *ex; 3150 unsigned int ee_len; 3151 int split_flag = 0, depth; 3152 3153 ext_debug("ext4_split_unwritten_extents: inode %lu, logical" 3154 "block %llu, max_blocks %u\n", inode->i_ino, 3155 (unsigned long long)map->m_lblk, map->m_len); 3156 3157 eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >> 3158 inode->i_sb->s_blocksize_bits; 3159 if (eof_block < map->m_lblk + map->m_len) 3160 eof_block = map->m_lblk + map->m_len; 3161 /* 3162 * It is safe to convert extent to initialized via explicit 3163 * zeroout only if extent is fully insde i_size or new_size. 3164 */ 3165 depth = ext_depth(inode); 3166 ex = path[depth].p_ext; 3167 ee_block = le32_to_cpu(ex->ee_block); 3168 ee_len = ext4_ext_get_actual_len(ex); 3169 3170 split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0; 3171 split_flag |= EXT4_EXT_MARK_UNINIT2; 3172 3173 flags |= EXT4_GET_BLOCKS_PRE_IO; 3174 return ext4_split_extent(handle, inode, path, map, split_flag, flags); 3175} 3176 3177static int ext4_convert_unwritten_extents_endio(handle_t *handle, 3178 struct inode *inode, 3179 struct ext4_ext_path *path) 3180{ 3181 struct ext4_extent *ex; 3182 int depth; 3183 int err = 0; 3184 3185 depth = ext_depth(inode); 3186 ex = path[depth].p_ext; 3187 3188 ext_debug("ext4_convert_unwritten_extents_endio: inode %lu, logical" 3189 "block %llu, max_blocks %u\n", inode->i_ino, 3190 (unsigned long long)le32_to_cpu(ex->ee_block), 3191 ext4_ext_get_actual_len(ex)); 3192 3193 err = ext4_ext_get_access(handle, inode, path + depth); 3194 if (err) 3195 goto out; 3196 /* first mark the extent as initialized */ 3197 ext4_ext_mark_initialized(ex); 3198 3199 /* note: ext4_ext_correct_indexes() isn't needed here because 3200 * borders are not changed 3201 */ 3202 ext4_ext_try_to_merge(inode, path, ex); 3203 3204 /* Mark modified extent as dirty */ 3205 err = ext4_ext_dirty(handle, inode, path + depth); 3206out: 3207 ext4_ext_show_leaf(inode, path); 3208 return err; 3209} 3210 3211static void unmap_underlying_metadata_blocks(struct block_device *bdev, 3212 sector_t block, int count) 3213{ 3214 int i; 3215 for (i = 0; i < count; i++) 3216 unmap_underlying_metadata(bdev, block + i); 3217} 3218 3219/* 3220 * Handle EOFBLOCKS_FL flag, clearing it if necessary 3221 */ 3222static int check_eofblocks_fl(handle_t *handle, struct inode *inode, 3223 ext4_lblk_t lblk, 3224 struct ext4_ext_path *path, 3225 unsigned int len) 3226{ 3227 int i, depth; 3228 struct ext4_extent_header *eh; 3229 struct ext4_extent *last_ex; 3230 3231 if (!ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS)) 3232 return 0; 3233 3234 depth = ext_depth(inode); 3235 eh = path[depth].p_hdr; 3236 3237 if (unlikely(!eh->eh_entries)) { 3238 EXT4_ERROR_INODE(inode, "eh->eh_entries == 0 and " 3239 "EOFBLOCKS_FL set"); 3240 return -EIO; 3241 } 3242 last_ex = EXT_LAST_EXTENT(eh); 3243 /* 3244 * We should clear the EOFBLOCKS_FL flag if we are writing the 3245 * last block in the last extent in the file. We test this by 3246 * first checking to see if the caller to 3247 * ext4_ext_get_blocks() was interested in the last block (or 3248 * a block beyond the last block) in the current extent. If 3249 * this turns out to be false, we can bail out from this 3250 * function immediately. 3251 */ 3252 if (lblk + len < le32_to_cpu(last_ex->ee_block) + 3253 ext4_ext_get_actual_len(last_ex)) 3254 return 0; 3255 /* 3256 * If the caller does appear to be planning to write at or 3257 * beyond the end of the current extent, we then test to see 3258 * if the current extent is the last extent in the file, by 3259 * checking to make sure it was reached via the rightmost node 3260 * at each level of the tree. 3261 */ 3262 for (i = depth-1; i >= 0; i--) 3263 if (path[i].p_idx != EXT_LAST_INDEX(path[i].p_hdr)) 3264 return 0; 3265 ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS); 3266 return ext4_mark_inode_dirty(handle, inode); 3267} 3268 3269/** 3270 * ext4_find_delalloc_range: find delayed allocated block in the given range. 3271 * 3272 * Goes through the buffer heads in the range [lblk_start, lblk_end] and returns 3273 * whether there are any buffers marked for delayed allocation. It returns '1' 3274 * on the first delalloc'ed buffer head found. If no buffer head in the given 3275 * range is marked for delalloc, it returns 0. 3276 * lblk_start should always be <= lblk_end. 3277 * search_hint_reverse is to indicate that searching in reverse from lblk_end to 3278 * lblk_start might be more efficient (i.e., we will likely hit the delalloc'ed 3279 * block sooner). This is useful when blocks are truncated sequentially from 3280 * lblk_start towards lblk_end. 3281 */ 3282static int ext4_find_delalloc_range(struct inode *inode, 3283 ext4_lblk_t lblk_start, 3284 ext4_lblk_t lblk_end, 3285 int search_hint_reverse) 3286{ 3287 struct address_space *mapping = inode->i_mapping; 3288 struct buffer_head *head, *bh = NULL; 3289 struct page *page; 3290 ext4_lblk_t i, pg_lblk; 3291 pgoff_t index; 3292 3293 /* reverse search wont work if fs block size is less than page size */ 3294 if (inode->i_blkbits < PAGE_CACHE_SHIFT) 3295 search_hint_reverse = 0; 3296 3297 if (search_hint_reverse) 3298 i = lblk_end; 3299 else 3300 i = lblk_start; 3301 3302 index = i >> (PAGE_CACHE_SHIFT - inode->i_blkbits); 3303 3304 while ((i >= lblk_start) && (i <= lblk_end)) { 3305 page = find_get_page(mapping, index); 3306 if (!page) 3307 goto nextpage; 3308 3309 if (!page_has_buffers(page)) 3310 goto nextpage; 3311 3312 head = page_buffers(page); 3313 if (!head) 3314 goto nextpage; 3315 3316 bh = head; 3317 pg_lblk = index << (PAGE_CACHE_SHIFT - 3318 inode->i_blkbits); 3319 do { 3320 if (unlikely(pg_lblk < lblk_start)) { 3321 /* 3322 * This is possible when fs block size is less 3323 * than page size and our cluster starts/ends in 3324 * middle of the page. So we need to skip the 3325 * initial few blocks till we reach the 'lblk' 3326 */ 3327 pg_lblk++; 3328 continue; 3329 } 3330 3331 /* Check if the buffer is delayed allocated and that it 3332 * is not yet mapped. (when da-buffers are mapped during 3333 * their writeout, their da_mapped bit is set.) 3334 */ 3335 if (buffer_delay(bh) && !buffer_da_mapped(bh)) { 3336 page_cache_release(page); 3337 trace_ext4_find_delalloc_range(inode, 3338 lblk_start, lblk_end, 3339 search_hint_reverse, 3340 1, i); 3341 return 1; 3342 } 3343 if (search_hint_reverse) 3344 i--; 3345 else 3346 i++; 3347 } while ((i >= lblk_start) && (i <= lblk_end) && 3348 ((bh = bh->b_this_page) != head)); 3349nextpage: 3350 if (page) 3351 page_cache_release(page); 3352 /* 3353 * Move to next page. 'i' will be the first lblk in the next 3354 * page. 3355 */ 3356 if (search_hint_reverse) 3357 index--; 3358 else 3359 index++; 3360 i = index << (PAGE_CACHE_SHIFT - inode->i_blkbits); 3361 } 3362 3363 trace_ext4_find_delalloc_range(inode, lblk_start, lblk_end, 3364 search_hint_reverse, 0, 0); 3365 return 0; 3366} 3367 3368int ext4_find_delalloc_cluster(struct inode *inode, ext4_lblk_t lblk, 3369 int search_hint_reverse) 3370{ 3371 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 3372 ext4_lblk_t lblk_start, lblk_end; 3373 lblk_start = lblk & (~(sbi->s_cluster_ratio - 1)); 3374 lblk_end = lblk_start + sbi->s_cluster_ratio - 1; 3375 3376 return ext4_find_delalloc_range(inode, lblk_start, lblk_end, 3377 search_hint_reverse); 3378} 3379 3380/** 3381 * Determines how many complete clusters (out of those specified by the 'map') 3382 * are under delalloc and were reserved quota for. 3383 * This function is called when we are writing out the blocks that were 3384 * originally written with their allocation delayed, but then the space was 3385 * allocated using fallocate() before the delayed allocation could be resolved. 3386 * The cases to look for are: 3387 * ('=' indicated delayed allocated blocks 3388 * '-' indicates non-delayed allocated blocks) 3389 * (a) partial clusters towards beginning and/or end outside of allocated range 3390 * are not delalloc'ed. 3391 * Ex: 3392 * |----c---=|====c====|====c====|===-c----| 3393 * |++++++ allocated ++++++| 3394 * ==> 4 complete clusters in above example 3395 * 3396 * (b) partial cluster (outside of allocated range) towards either end is 3397 * marked for delayed allocation. In this case, we will exclude that 3398 * cluster. 3399 * Ex: 3400 * |----====c========|========c========| 3401 * |++++++ allocated ++++++| 3402 * ==> 1 complete clusters in above example 3403 * 3404 * Ex: 3405 * |================c================| 3406 * |++++++ allocated ++++++| 3407 * ==> 0 complete clusters in above example 3408 * 3409 * The ext4_da_update_reserve_space will be called only if we 3410 * determine here that there were some "entire" clusters that span 3411 * this 'allocated' range. 3412 * In the non-bigalloc case, this function will just end up returning num_blks 3413 * without ever calling ext4_find_delalloc_range. 3414 */ 3415static unsigned int 3416get_reserved_cluster_alloc(struct inode *inode, ext4_lblk_t lblk_start, 3417 unsigned int num_blks) 3418{ 3419 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 3420 ext4_lblk_t alloc_cluster_start, alloc_cluster_end; 3421 ext4_lblk_t lblk_from, lblk_to, c_offset; 3422 unsigned int allocated_clusters = 0; 3423 3424 alloc_cluster_start = EXT4_B2C(sbi, lblk_start); 3425 alloc_cluster_end = EXT4_B2C(sbi, lblk_start + num_blks - 1); 3426 3427 /* max possible clusters for this allocation */ 3428 allocated_clusters = alloc_cluster_end - alloc_cluster_start + 1; 3429 3430 trace_ext4_get_reserved_cluster_alloc(inode, lblk_start, num_blks); 3431 3432 /* Check towards left side */ 3433 c_offset = lblk_start & (sbi->s_cluster_ratio - 1); 3434 if (c_offset) { 3435 lblk_from = lblk_start & (~(sbi->s_cluster_ratio - 1)); 3436 lblk_to = lblk_from + c_offset - 1; 3437 3438 if (ext4_find_delalloc_range(inode, lblk_from, lblk_to, 0)) 3439 allocated_clusters--; 3440 } 3441 3442 /* Now check towards right. */ 3443 c_offset = (lblk_start + num_blks) & (sbi->s_cluster_ratio - 1); 3444 if (allocated_clusters && c_offset) { 3445 lblk_from = lblk_start + num_blks; 3446 lblk_to = lblk_from + (sbi->s_cluster_ratio - c_offset) - 1; 3447 3448 if (ext4_find_delalloc_range(inode, lblk_from, lblk_to, 0)) 3449 allocated_clusters--; 3450 } 3451 3452 return allocated_clusters; 3453} 3454 3455static int 3456ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode, 3457 struct ext4_map_blocks *map, 3458 struct ext4_ext_path *path, int flags, 3459 unsigned int allocated, ext4_fsblk_t newblock) 3460{ 3461 int ret = 0; 3462 int err = 0; 3463 ext4_io_end_t *io = EXT4_I(inode)->cur_aio_dio; 3464 3465 ext_debug("ext4_ext_handle_uninitialized_extents: inode %lu, logical" 3466 "block %llu, max_blocks %u, flags %d, allocated %u", 3467 inode->i_ino, (unsigned long long)map->m_lblk, map->m_len, 3468 flags, allocated); 3469 ext4_ext_show_leaf(inode, path); 3470 3471 trace_ext4_ext_handle_uninitialized_extents(inode, map, allocated, 3472 newblock); 3473 3474 /* get_block() before submit the IO, split the extent */ 3475 if ((flags & EXT4_GET_BLOCKS_PRE_IO)) { 3476 ret = ext4_split_unwritten_extents(handle, inode, map, 3477 path, flags); 3478 /* 3479 * Flag the inode(non aio case) or end_io struct (aio case) 3480 * that this IO needs to conversion to written when IO is 3481 * completed 3482 */ 3483 if (io) { 3484 if (!(io->flag & EXT4_IO_END_UNWRITTEN)) { 3485 io->flag = EXT4_IO_END_UNWRITTEN; 3486 atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten); 3487 } 3488 } else 3489 ext4_set_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN); 3490 if (ext4_should_dioread_nolock(inode)) 3491 map->m_flags |= EXT4_MAP_UNINIT; 3492 goto out; 3493 } 3494 /* IO end_io complete, convert the filled extent to written */ 3495 if ((flags & EXT4_GET_BLOCKS_CONVERT)) { 3496 ret = ext4_convert_unwritten_extents_endio(handle, inode, 3497 path); 3498 if (ret >= 0) { 3499 ext4_update_inode_fsync_trans(handle, inode, 1); 3500 err = check_eofblocks_fl(handle, inode, map->m_lblk, 3501 path, map->m_len); 3502 } else 3503 err = ret; 3504 goto out2; 3505 } 3506 /* buffered IO case */ 3507 /* 3508 * repeat fallocate creation request 3509 * we already have an unwritten extent 3510 */ 3511 if (flags & EXT4_GET_BLOCKS_UNINIT_EXT) 3512 goto map_out; 3513 3514 /* buffered READ or buffered write_begin() lookup */ 3515 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) { 3516 /* 3517 * We have blocks reserved already. We 3518 * return allocated blocks so that delalloc 3519 * won't do block reservation for us. But 3520 * the buffer head will be unmapped so that 3521 * a read from the block returns 0s. 3522 */ 3523 map->m_flags |= EXT4_MAP_UNWRITTEN; 3524 goto out1; 3525 } 3526 3527 /* buffered write, writepage time, convert*/ 3528 ret = ext4_ext_convert_to_initialized(handle, inode, map, path); 3529 if (ret >= 0) 3530 ext4_update_inode_fsync_trans(handle, inode, 1); 3531out: 3532 if (ret <= 0) { 3533 err = ret; 3534 goto out2; 3535 } else 3536 allocated = ret; 3537 map->m_flags |= EXT4_MAP_NEW; 3538 /* 3539 * if we allocated more blocks than requested 3540 * we need to make sure we unmap the extra block 3541 * allocated. The actual needed block will get 3542 * unmapped later when we find the buffer_head marked 3543 * new. 3544 */ 3545 if (allocated > map->m_len) { 3546 unmap_underlying_metadata_blocks(inode->i_sb->s_bdev, 3547 newblock + map->m_len, 3548 allocated - map->m_len); 3549 allocated = map->m_len; 3550 } 3551 3552 /* 3553 * If we have done fallocate with the offset that is already 3554 * delayed allocated, we would have block reservation 3555 * and quota reservation done in the delayed write path. 3556 * But fallocate would have already updated quota and block 3557 * count for this offset. So cancel these reservation 3558 */ 3559 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) { 3560 unsigned int reserved_clusters; 3561 reserved_clusters = get_reserved_cluster_alloc(inode, 3562 map->m_lblk, map->m_len); 3563 if (reserved_clusters) 3564 ext4_da_update_reserve_space(inode, 3565 reserved_clusters, 3566 0); 3567 } 3568 3569map_out: 3570 map->m_flags |= EXT4_MAP_MAPPED; 3571 if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0) { 3572 err = check_eofblocks_fl(handle, inode, map->m_lblk, path, 3573 map->m_len); 3574 if (err < 0) 3575 goto out2; 3576 } 3577out1: 3578 if (allocated > map->m_len) 3579 allocated = map->m_len; 3580 ext4_ext_show_leaf(inode, path); 3581 map->m_pblk = newblock; 3582 map->m_len = allocated; 3583out2: 3584 if (path) { 3585 ext4_ext_drop_refs(path); 3586 kfree(path); 3587 } 3588 return err ? err : allocated; 3589} 3590 3591/* 3592 * get_implied_cluster_alloc - check to see if the requested 3593 * allocation (in the map structure) overlaps with a cluster already 3594 * allocated in an extent. 3595 * @sb The filesystem superblock structure 3596 * @map The requested lblk->pblk mapping 3597 * @ex The extent structure which might contain an implied 3598 * cluster allocation 3599 * 3600 * This function is called by ext4_ext_map_blocks() after we failed to 3601 * find blocks that were already in the inode's extent tree. Hence, 3602 * we know that the beginning of the requested region cannot overlap 3603 * the extent from the inode's extent tree. There are three cases we 3604 * want to catch. The first is this case: 3605 * 3606 * |--- cluster # N--| 3607 * |--- extent ---| |---- requested region ---| 3608 * |==========| 3609 * 3610 * The second case that we need to test for is this one: 3611 * 3612 * |--------- cluster # N ----------------| 3613 * |--- requested region --| |------- extent ----| 3614 * |=======================| 3615 * 3616 * The third case is when the requested region lies between two extents 3617 * within the same cluster: 3618 * |------------- cluster # N-------------| 3619 * |----- ex -----| |---- ex_right ----| 3620 * |------ requested region ------| 3621 * |================| 3622 * 3623 * In each of the above cases, we need to set the map->m_pblk and 3624 * map->m_len so it corresponds to the return the extent labelled as 3625 * "|====|" from cluster #N, since it is already in use for data in 3626 * cluster EXT4_B2C(sbi, map->m_lblk). We will then return 1 to 3627 * signal to ext4_ext_map_blocks() that map->m_pblk should be treated 3628 * as a new "allocated" block region. Otherwise, we will return 0 and 3629 * ext4_ext_map_blocks() will then allocate one or more new clusters 3630 * by calling ext4_mb_new_blocks(). 3631 */ 3632static int get_implied_cluster_alloc(struct super_block *sb, 3633 struct ext4_map_blocks *map, 3634 struct ext4_extent *ex, 3635 struct ext4_ext_path *path) 3636{ 3637 struct ext4_sb_info *sbi = EXT4_SB(sb); 3638 ext4_lblk_t c_offset = map->m_lblk & (sbi->s_cluster_ratio-1); 3639 ext4_lblk_t ex_cluster_start, ex_cluster_end; 3640 ext4_lblk_t rr_cluster_start, rr_cluster_end; 3641 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block); 3642 ext4_fsblk_t ee_start = ext4_ext_pblock(ex); 3643 unsigned short ee_len = ext4_ext_get_actual_len(ex); 3644 3645 /* The extent passed in that we are trying to match */ 3646 ex_cluster_start = EXT4_B2C(sbi, ee_block); 3647 ex_cluster_end = EXT4_B2C(sbi, ee_block + ee_len - 1); 3648 3649 /* The requested region passed into ext4_map_blocks() */ 3650 rr_cluster_start = EXT4_B2C(sbi, map->m_lblk); 3651 rr_cluster_end = EXT4_B2C(sbi, map->m_lblk + map->m_len - 1); 3652 3653 if ((rr_cluster_start == ex_cluster_end) || 3654 (rr_cluster_start == ex_cluster_start)) { 3655 if (rr_cluster_start == ex_cluster_end) 3656 ee_start += ee_len - 1; 3657 map->m_pblk = (ee_start & ~(sbi->s_cluster_ratio - 1)) + 3658 c_offset; 3659 map->m_len = min(map->m_len, 3660 (unsigned) sbi->s_cluster_ratio - c_offset); 3661 /* 3662 * Check for and handle this case: 3663 * 3664 * |--------- cluster # N-------------| 3665 * |------- extent ----| 3666 * |--- requested region ---| 3667 * |===========| 3668 */ 3669 3670 if (map->m_lblk < ee_block) 3671 map->m_len = min(map->m_len, ee_block - map->m_lblk); 3672 3673 /* 3674 * Check for the case where there is already another allocated 3675 * block to the right of 'ex' but before the end of the cluster. 3676 * 3677 * |------------- cluster # N-------------| 3678 * |----- ex -----| |---- ex_right ----| 3679 * |------ requested region ------| 3680 * |================| 3681 */ 3682 if (map->m_lblk > ee_block) { 3683 ext4_lblk_t next = ext4_ext_next_allocated_block(path); 3684 map->m_len = min(map->m_len, next - map->m_lblk); 3685 } 3686 3687 trace_ext4_get_implied_cluster_alloc_exit(sb, map, 1); 3688 return 1; 3689 } 3690 3691 trace_ext4_get_implied_cluster_alloc_exit(sb, map, 0); 3692 return 0; 3693} 3694 3695 3696/* 3697 * Block allocation/map/preallocation routine for extents based files 3698 * 3699 * 3700 * Need to be called with 3701 * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block 3702 * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem) 3703 * 3704 * return > 0, number of of blocks already mapped/allocated 3705 * if create == 0 and these are pre-allocated blocks 3706 * buffer head is unmapped 3707 * otherwise blocks are mapped 3708 * 3709 * return = 0, if plain look up failed (blocks have not been allocated) 3710 * buffer head is unmapped 3711 * 3712 * return < 0, error case. 3713 */ 3714int ext4_ext_map_blocks(handle_t *handle, struct inode *inode, 3715 struct ext4_map_blocks *map, int flags) 3716{ 3717 struct ext4_ext_path *path = NULL; 3718 struct ext4_extent newex, *ex, *ex2; 3719 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 3720 ext4_fsblk_t newblock = 0; 3721 int free_on_err = 0, err = 0, depth, ret; 3722 unsigned int allocated = 0, offset = 0; 3723 unsigned int allocated_clusters = 0; 3724 unsigned int punched_out = 0; 3725 unsigned int result = 0; 3726 struct ext4_allocation_request ar; 3727 ext4_io_end_t *io = EXT4_I(inode)->cur_aio_dio; 3728 ext4_lblk_t cluster_offset; 3729 3730 ext_debug("blocks %u/%u requested for inode %lu\n", 3731 map->m_lblk, map->m_len, inode->i_ino); 3732 trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags); 3733 3734 /* check in cache */ 3735 if (!(flags & EXT4_GET_BLOCKS_PUNCH_OUT_EXT) && 3736 ext4_ext_in_cache(inode, map->m_lblk, &newex)) { 3737 if (!newex.ee_start_lo && !newex.ee_start_hi) { 3738 if ((sbi->s_cluster_ratio > 1) && 3739 ext4_find_delalloc_cluster(inode, map->m_lblk, 0)) 3740 map->m_flags |= EXT4_MAP_FROM_CLUSTER; 3741 3742 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) { 3743 /* 3744 * block isn't allocated yet and 3745 * user doesn't want to allocate it 3746 */ 3747 goto out2; 3748 } 3749 /* we should allocate requested block */ 3750 } else { 3751 /* block is already allocated */ 3752 if (sbi->s_cluster_ratio > 1) 3753 map->m_flags |= EXT4_MAP_FROM_CLUSTER; 3754 newblock = map->m_lblk 3755 - le32_to_cpu(newex.ee_block) 3756 + ext4_ext_pblock(&newex); 3757 /* number of remaining blocks in the extent */ 3758 allocated = ext4_ext_get_actual_len(&newex) - 3759 (map->m_lblk - le32_to_cpu(newex.ee_block)); 3760 goto out; 3761 } 3762 } 3763 3764 /* find extent for this block */ 3765 path = ext4_ext_find_extent(inode, map->m_lblk, NULL); 3766 if (IS_ERR(path)) { 3767 err = PTR_ERR(path); 3768 path = NULL; 3769 goto out2; 3770 } 3771 3772 depth = ext_depth(inode); 3773 3774 /* 3775 * consistent leaf must not be empty; 3776 * this situation is possible, though, _during_ tree modification; 3777 * this is why assert can't be put in ext4_ext_find_extent() 3778 */ 3779 if (unlikely(path[depth].p_ext == NULL && depth != 0)) { 3780 EXT4_ERROR_INODE(inode, "bad extent address " 3781 "lblock: %lu, depth: %d pblock %lld", 3782 (unsigned long) map->m_lblk, depth, 3783 path[depth].p_block); 3784 err = -EIO; 3785 goto out2; 3786 } 3787 3788 ex = path[depth].p_ext; 3789 if (ex) { 3790 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block); 3791 ext4_fsblk_t ee_start = ext4_ext_pblock(ex); 3792 unsigned short ee_len; 3793 3794 /* 3795 * Uninitialized extents are treated as holes, except that 3796 * we split out initialized portions during a write. 3797 */ 3798 ee_len = ext4_ext_get_actual_len(ex); 3799 3800 trace_ext4_ext_show_extent(inode, ee_block, ee_start, ee_len); 3801 3802 /* if found extent covers block, simply return it */ 3803 if (in_range(map->m_lblk, ee_block, ee_len)) { 3804 struct ext4_map_blocks punch_map; 3805 ext4_fsblk_t partial_cluster = 0; 3806 3807 newblock = map->m_lblk - ee_block + ee_start; 3808 /* number of remaining blocks in the extent */ 3809 allocated = ee_len - (map->m_lblk - ee_block); 3810 ext_debug("%u fit into %u:%d -> %llu\n", map->m_lblk, 3811 ee_block, ee_len, newblock); 3812 3813 if ((flags & EXT4_GET_BLOCKS_PUNCH_OUT_EXT) == 0) { 3814 /* 3815 * Do not put uninitialized extent 3816 * in the cache 3817 */ 3818 if (!ext4_ext_is_uninitialized(ex)) { 3819 ext4_ext_put_in_cache(inode, ee_block, 3820 ee_len, ee_start); 3821 goto out; 3822 } 3823 ret = ext4_ext_handle_uninitialized_extents( 3824 handle, inode, map, path, flags, 3825 allocated, newblock); 3826 return ret; 3827 } 3828 3829 /* 3830 * Punch out the map length, but only to the 3831 * end of the extent 3832 */ 3833 punched_out = allocated < map->m_len ? 3834 allocated : map->m_len; 3835 3836 /* 3837 * Sense extents need to be converted to 3838 * uninitialized, they must fit in an 3839 * uninitialized extent 3840 */ 3841 if (punched_out > EXT_UNINIT_MAX_LEN) 3842 punched_out = EXT_UNINIT_MAX_LEN; 3843 3844 punch_map.m_lblk = map->m_lblk; 3845 punch_map.m_pblk = newblock; 3846 punch_map.m_len = punched_out; 3847 punch_map.m_flags = 0; 3848 3849 /* Check to see if the extent needs to be split */ 3850 if (punch_map.m_len != ee_len || 3851 punch_map.m_lblk != ee_block) { 3852 3853 ret = ext4_split_extent(handle, inode, 3854 path, &punch_map, 0, 3855 EXT4_GET_BLOCKS_PUNCH_OUT_EXT | 3856 EXT4_GET_BLOCKS_PRE_IO); 3857 3858 if (ret < 0) { 3859 err = ret; 3860 goto out2; 3861 } 3862 /* 3863 * find extent for the block at 3864 * the start of the hole 3865 */ 3866 ext4_ext_drop_refs(path); 3867 kfree(path); 3868 3869 path = ext4_ext_find_extent(inode, 3870 map->m_lblk, NULL); 3871 if (IS_ERR(path)) { 3872 err = PTR_ERR(path); 3873 path = NULL; 3874 goto out2; 3875 } 3876 3877 depth = ext_depth(inode); 3878 ex = path[depth].p_ext; 3879 ee_len = ext4_ext_get_actual_len(ex); 3880 ee_block = le32_to_cpu(ex->ee_block); 3881 ee_start = ext4_ext_pblock(ex); 3882 3883 } 3884 3885 ext4_ext_mark_uninitialized(ex); 3886 3887 ext4_ext_invalidate_cache(inode); 3888 3889 err = ext4_ext_rm_leaf(handle, inode, path, 3890 &partial_cluster, map->m_lblk, 3891 map->m_lblk + punched_out); 3892 3893 if (!err && path->p_hdr->eh_entries == 0) { 3894 /* 3895 * Punch hole freed all of this sub tree, 3896 * so we need to correct eh_depth 3897 */ 3898 err = ext4_ext_get_access(handle, inode, path); 3899 if (err == 0) { 3900 ext_inode_hdr(inode)->eh_depth = 0; 3901 ext_inode_hdr(inode)->eh_max = 3902 cpu_to_le16(ext4_ext_space_root( 3903 inode, 0)); 3904 3905 err = ext4_ext_dirty( 3906 handle, inode, path); 3907 } 3908 } 3909 3910 goto out2; 3911 } 3912 } 3913 3914 if ((sbi->s_cluster_ratio > 1) && 3915 ext4_find_delalloc_cluster(inode, map->m_lblk, 0)) 3916 map->m_flags |= EXT4_MAP_FROM_CLUSTER; 3917 3918 /* 3919 * requested block isn't allocated yet; 3920 * we couldn't try to create block if create flag is zero 3921 */ 3922 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) { 3923 /* 3924 * put just found gap into cache to speed up 3925 * subsequent requests 3926 */ 3927 ext4_ext_put_gap_in_cache(inode, path, map->m_lblk); 3928 goto out2; 3929 } 3930 3931 /* 3932 * Okay, we need to do block allocation. 3933 */ 3934 map->m_flags &= ~EXT4_MAP_FROM_CLUSTER; 3935 newex.ee_block = cpu_to_le32(map->m_lblk); 3936 cluster_offset = map->m_lblk & (sbi->s_cluster_ratio-1); 3937 3938 /* 3939 * If we are doing bigalloc, check to see if the extent returned 3940 * by ext4_ext_find_extent() implies a cluster we can use. 3941 */ 3942 if (cluster_offset && ex && 3943 get_implied_cluster_alloc(inode->i_sb, map, ex, path)) { 3944 ar.len = allocated = map->m_len; 3945 newblock = map->m_pblk; 3946 map->m_flags |= EXT4_MAP_FROM_CLUSTER; 3947 goto got_allocated_blocks; 3948 } 3949 3950 /* find neighbour allocated blocks */ 3951 ar.lleft = map->m_lblk; 3952 err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft); 3953 if (err) 3954 goto out2; 3955 ar.lright = map->m_lblk; 3956 ex2 = NULL; 3957 err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright, &ex2); 3958 if (err) 3959 goto out2; 3960 3961 /* Check if the extent after searching to the right implies a 3962 * cluster we can use. */ 3963 if ((sbi->s_cluster_ratio > 1) && ex2 && 3964 get_implied_cluster_alloc(inode->i_sb, map, ex2, path)) { 3965 ar.len = allocated = map->m_len; 3966 newblock = map->m_pblk; 3967 map->m_flags |= EXT4_MAP_FROM_CLUSTER; 3968 goto got_allocated_blocks; 3969 } 3970 3971 /* 3972 * See if request is beyond maximum number of blocks we can have in 3973 * a single extent. For an initialized extent this limit is 3974 * EXT_INIT_MAX_LEN and for an uninitialized extent this limit is 3975 * EXT_UNINIT_MAX_LEN. 3976 */ 3977 if (map->m_len > EXT_INIT_MAX_LEN && 3978 !(flags & EXT4_GET_BLOCKS_UNINIT_EXT)) 3979 map->m_len = EXT_INIT_MAX_LEN; 3980 else if (map->m_len > EXT_UNINIT_MAX_LEN && 3981 (flags & EXT4_GET_BLOCKS_UNINIT_EXT)) 3982 map->m_len = EXT_UNINIT_MAX_LEN; 3983 3984 /* Check if we can really insert (m_lblk)::(m_lblk + m_len) extent */ 3985 newex.ee_len = cpu_to_le16(map->m_len); 3986 err = ext4_ext_check_overlap(sbi, inode, &newex, path); 3987 if (err) 3988 allocated = ext4_ext_get_actual_len(&newex); 3989 else 3990 allocated = map->m_len; 3991 3992 /* allocate new block */ 3993 ar.inode = inode; 3994 ar.goal = ext4_ext_find_goal(inode, path, map->m_lblk); 3995 ar.logical = map->m_lblk; 3996 /* 3997 * We calculate the offset from the beginning of the cluster 3998 * for the logical block number, since when we allocate a 3999 * physical cluster, the physical block should start at the 4000 * same offset from the beginning of the cluster. This is 4001 * needed so that future calls to get_implied_cluster_alloc() 4002 * work correctly. 4003 */ 4004 offset = map->m_lblk & (sbi->s_cluster_ratio - 1); 4005 ar.len = EXT4_NUM_B2C(sbi, offset+allocated); 4006 ar.goal -= offset; 4007 ar.logical -= offset; 4008 if (S_ISREG(inode->i_mode)) 4009 ar.flags = EXT4_MB_HINT_DATA; 4010 else 4011 /* disable in-core preallocation for non-regular files */ 4012 ar.flags = 0; 4013 if (flags & EXT4_GET_BLOCKS_NO_NORMALIZE) 4014 ar.flags |= EXT4_MB_HINT_NOPREALLOC; 4015 newblock = ext4_mb_new_blocks(handle, &ar, &err); 4016 if (!newblock) 4017 goto out2; 4018 ext_debug("allocate new block: goal %llu, found %llu/%u\n", 4019 ar.goal, newblock, allocated); 4020 free_on_err = 1; 4021 allocated_clusters = ar.len; 4022 ar.len = EXT4_C2B(sbi, ar.len) - offset; 4023 if (ar.len > allocated) 4024 ar.len = allocated; 4025 4026got_allocated_blocks: 4027 /* try to insert new extent into found leaf and return */ 4028 ext4_ext_store_pblock(&newex, newblock + offset); 4029 newex.ee_len = cpu_to_le16(ar.len); 4030 /* Mark uninitialized */ 4031 if (flags & EXT4_GET_BLOCKS_UNINIT_EXT){ 4032 ext4_ext_mark_uninitialized(&newex); 4033 /* 4034 * io_end structure was created for every IO write to an 4035 * uninitialized extent. To avoid unnecessary conversion, 4036 * here we flag the IO that really needs the conversion. 4037 * For non asycn direct IO case, flag the inode state 4038 * that we need to perform conversion when IO is done. 4039 */ 4040 if ((flags & EXT4_GET_BLOCKS_PRE_IO)) { 4041 if (io) { 4042 if (!(io->flag & EXT4_IO_END_UNWRITTEN)) { 4043 io->flag = EXT4_IO_END_UNWRITTEN; 4044 atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten); 4045 } 4046 } else 4047 ext4_set_inode_state(inode, 4048 EXT4_STATE_DIO_UNWRITTEN); 4049 } 4050 if (ext4_should_dioread_nolock(inode)) 4051 map->m_flags |= EXT4_MAP_UNINIT; 4052 } 4053 4054 err = 0; 4055 if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0) 4056 err = check_eofblocks_fl(handle, inode, map->m_lblk, 4057 path, ar.len); 4058 if (!err) 4059 err = ext4_ext_insert_extent(handle, inode, path, 4060 &newex, flags); 4061 if (err && free_on_err) { 4062 int fb_flags = flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE ? 4063 EXT4_FREE_BLOCKS_NO_QUOT_UPDATE : 0; 4064 /* free data blocks we just allocated */ 4065 /* not a good idea to call discard here directly, 4066 * but otherwise we'd need to call it every free() */ 4067 ext4_discard_preallocations(inode); 4068 ext4_free_blocks(handle, inode, NULL, ext4_ext_pblock(&newex), 4069 ext4_ext_get_actual_len(&newex), fb_flags); 4070 goto out2; 4071 } 4072 4073 /* previous routine could use block we allocated */ 4074 newblock = ext4_ext_pblock(&newex); 4075 allocated = ext4_ext_get_actual_len(&newex); 4076 if (allocated > map->m_len) 4077 allocated = map->m_len; 4078 map->m_flags |= EXT4_MAP_NEW; 4079 4080 /* 4081 * Update reserved blocks/metadata blocks after successful 4082 * block allocation which had been deferred till now. 4083 */ 4084 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) { 4085 unsigned int reserved_clusters; 4086 /* 4087 * Check how many clusters we had reserved this allocated range 4088 */ 4089 reserved_clusters = get_reserved_cluster_alloc(inode, 4090 map->m_lblk, allocated); 4091 if (map->m_flags & EXT4_MAP_FROM_CLUSTER) { 4092 if (reserved_clusters) { 4093 /* 4094 * We have clusters reserved for this range. 4095 * But since we are not doing actual allocation 4096 * and are simply using blocks from previously 4097 * allocated cluster, we should release the 4098 * reservation and not claim quota. 4099 */ 4100 ext4_da_update_reserve_space(inode, 4101 reserved_clusters, 0); 4102 } 4103 } else { 4104 BUG_ON(allocated_clusters < reserved_clusters); 4105 /* We will claim quota for all newly allocated blocks.*/ 4106 ext4_da_update_reserve_space(inode, allocated_clusters, 4107 1); 4108 if (reserved_clusters < allocated_clusters) { 4109 struct ext4_inode_info *ei = EXT4_I(inode); 4110 int reservation = allocated_clusters - 4111 reserved_clusters; 4112 /* 4113 * It seems we claimed few clusters outside of 4114 * the range of this allocation. We should give 4115 * it back to the reservation pool. This can 4116 * happen in the following case: 4117 * 4118 * * Suppose s_cluster_ratio is 4 (i.e., each 4119 * cluster has 4 blocks. Thus, the clusters 4120 * are [0-3],[4-7],[8-11]... 4121 * * First comes delayed allocation write for 4122 * logical blocks 10 & 11. Since there were no 4123 * previous delayed allocated blocks in the 4124 * range [8-11], we would reserve 1 cluster 4125 * for this write. 4126 * * Next comes write for logical blocks 3 to 8. 4127 * In this case, we will reserve 2 clusters 4128 * (for [0-3] and [4-7]; and not for [8-11] as 4129 * that range has a delayed allocated blocks. 4130 * Thus total reserved clusters now becomes 3. 4131 * * Now, during the delayed allocation writeout 4132 * time, we will first write blocks [3-8] and 4133 * allocate 3 clusters for writing these 4134 * blocks. Also, we would claim all these 4135 * three clusters above. 4136 * * Now when we come here to writeout the 4137 * blocks [10-11], we would expect to claim 4138 * the reservation of 1 cluster we had made 4139 * (and we would claim it since there are no 4140 * more delayed allocated blocks in the range 4141 * [8-11]. But our reserved cluster count had 4142 * already gone to 0. 4143 * 4144 * Thus, at the step 4 above when we determine 4145 * that there are still some unwritten delayed 4146 * allocated blocks outside of our current 4147 * block range, we should increment the 4148 * reserved clusters count so that when the 4149 * remaining blocks finally gets written, we 4150 * could claim them. 4151 */ 4152 dquot_reserve_block(inode, 4153 EXT4_C2B(sbi, reservation)); 4154 spin_lock(&ei->i_block_reservation_lock); 4155 ei->i_reserved_data_blocks += reservation; 4156 spin_unlock(&ei->i_block_reservation_lock); 4157 } 4158 } 4159 } 4160 4161 /* 4162 * Cache the extent and update transaction to commit on fdatasync only 4163 * when it is _not_ an uninitialized extent. 4164 */ 4165 if ((flags & EXT4_GET_BLOCKS_UNINIT_EXT) == 0) { 4166 ext4_ext_put_in_cache(inode, map->m_lblk, allocated, newblock); 4167 ext4_update_inode_fsync_trans(handle, inode, 1); 4168 } else 4169 ext4_update_inode_fsync_trans(handle, inode, 0); 4170out: 4171 if (allocated > map->m_len) 4172 allocated = map->m_len; 4173 ext4_ext_show_leaf(inode, path); 4174 map->m_flags |= EXT4_MAP_MAPPED; 4175 map->m_pblk = newblock; 4176 map->m_len = allocated; 4177out2: 4178 if (path) { 4179 ext4_ext_drop_refs(path); 4180 kfree(path); 4181 } 4182 trace_ext4_ext_map_blocks_exit(inode, map->m_lblk, 4183 newblock, map->m_len, err ? err : allocated); 4184 4185 result = (flags & EXT4_GET_BLOCKS_PUNCH_OUT_EXT) ? 4186 punched_out : allocated; 4187 4188 return err ? err : result; 4189} 4190 4191void ext4_ext_truncate(struct inode *inode) 4192{ 4193 struct address_space *mapping = inode->i_mapping; 4194 struct super_block *sb = inode->i_sb; 4195 ext4_lblk_t last_block; 4196 handle_t *handle; 4197 loff_t page_len; 4198 int err = 0; 4199 4200 /* 4201 * finish any pending end_io work so we won't run the risk of 4202 * converting any truncated blocks to initialized later 4203 */ 4204 ext4_flush_completed_IO(inode); 4205 4206 /* 4207 * probably first extent we're gonna free will be last in block 4208 */ 4209 err = ext4_writepage_trans_blocks(inode); 4210 handle = ext4_journal_start(inode, err); 4211 if (IS_ERR(handle)) 4212 return; 4213 4214 if (inode->i_size % PAGE_CACHE_SIZE != 0) { 4215 page_len = PAGE_CACHE_SIZE - 4216 (inode->i_size & (PAGE_CACHE_SIZE - 1)); 4217 4218 err = ext4_discard_partial_page_buffers(handle, 4219 mapping, inode->i_size, page_len, 0); 4220 4221 if (err) 4222 goto out_stop; 4223 } 4224 4225 if (ext4_orphan_add(handle, inode)) 4226 goto out_stop; 4227 4228 down_write(&EXT4_I(inode)->i_data_sem); 4229 ext4_ext_invalidate_cache(inode); 4230 4231 ext4_discard_preallocations(inode); 4232 4233 /* 4234 * TODO: optimization is possible here. 4235 * Probably we need not scan at all, 4236 * because page truncation is enough. 4237 */ 4238 4239 /* we have to know where to truncate from in crash case */ 4240 EXT4_I(inode)->i_disksize = inode->i_size; 4241 ext4_mark_inode_dirty(handle, inode); 4242 4243 last_block = (inode->i_size + sb->s_blocksize - 1) 4244 >> EXT4_BLOCK_SIZE_BITS(sb); 4245 err = ext4_ext_remove_space(inode, last_block); 4246 4247 /* In a multi-transaction truncate, we only make the final 4248 * transaction synchronous. 4249 */ 4250 if (IS_SYNC(inode)) 4251 ext4_handle_sync(handle); 4252 4253 up_write(&EXT4_I(inode)->i_data_sem); 4254 4255out_stop: 4256 /* 4257 * If this was a simple ftruncate() and the file will remain alive, 4258 * then we need to clear up the orphan record which we created above. 4259 * However, if this was a real unlink then we were called by 4260 * ext4_delete_inode(), and we allow that function to clean up the 4261 * orphan info for us. 4262 */ 4263 if (inode->i_nlink) 4264 ext4_orphan_del(handle, inode); 4265 4266 inode->i_mtime = inode->i_ctime = ext4_current_time(inode); 4267 ext4_mark_inode_dirty(handle, inode); 4268 ext4_journal_stop(handle); 4269} 4270 4271static void ext4_falloc_update_inode(struct inode *inode, 4272 int mode, loff_t new_size, int update_ctime) 4273{ 4274 struct timespec now; 4275 4276 if (update_ctime) { 4277 now = current_fs_time(inode->i_sb); 4278 if (!timespec_equal(&inode->i_ctime, &now)) 4279 inode->i_ctime = now; 4280 } 4281 /* 4282 * Update only when preallocation was requested beyond 4283 * the file size. 4284 */ 4285 if (!(mode & FALLOC_FL_KEEP_SIZE)) { 4286 if (new_size > i_size_read(inode)) 4287 i_size_write(inode, new_size); 4288 if (new_size > EXT4_I(inode)->i_disksize) 4289 ext4_update_i_disksize(inode, new_size); 4290 } else { 4291 /* 4292 * Mark that we allocate beyond EOF so the subsequent truncate 4293 * can proceed even if the new size is the same as i_size. 4294 */ 4295 if (new_size > i_size_read(inode)) 4296 ext4_set_inode_flag(inode, EXT4_INODE_EOFBLOCKS); 4297 } 4298 4299} 4300 4301/* 4302 * preallocate space for a file. This implements ext4's fallocate file 4303 * operation, which gets called from sys_fallocate system call. 4304 * For block-mapped files, posix_fallocate should fall back to the method 4305 * of writing zeroes to the required new blocks (the same behavior which is 4306 * expected for file systems which do not support fallocate() system call). 4307 */ 4308long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len) 4309{ 4310 struct inode *inode = file->f_path.dentry->d_inode; 4311 handle_t *handle; 4312 loff_t new_size; 4313 unsigned int max_blocks; 4314 int ret = 0; 4315 int ret2 = 0; 4316 int retries = 0; 4317 int flags; 4318 struct ext4_map_blocks map; 4319 unsigned int credits, blkbits = inode->i_blkbits; 4320 4321 /* 4322 * currently supporting (pre)allocate mode for extent-based 4323 * files _only_ 4324 */ 4325 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) 4326 return -EOPNOTSUPP; 4327 4328 /* Return error if mode is not supported */ 4329 if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE)) 4330 return -EOPNOTSUPP; 4331 4332 if (mode & FALLOC_FL_PUNCH_HOLE) 4333 return ext4_punch_hole(file, offset, len); 4334 4335 trace_ext4_fallocate_enter(inode, offset, len, mode); 4336 map.m_lblk = offset >> blkbits; 4337 /* 4338 * We can't just convert len to max_blocks because 4339 * If blocksize = 4096 offset = 3072 and len = 2048 4340 */ 4341 max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits) 4342 - map.m_lblk; 4343 /* 4344 * credits to insert 1 extent into extent tree 4345 */ 4346 credits = ext4_chunk_trans_blocks(inode, max_blocks); 4347 mutex_lock(&inode->i_mutex); 4348 ret = inode_newsize_ok(inode, (len + offset)); 4349 if (ret) { 4350 mutex_unlock(&inode->i_mutex); 4351 trace_ext4_fallocate_exit(inode, offset, max_blocks, ret); 4352 return ret; 4353 } 4354 flags = EXT4_GET_BLOCKS_CREATE_UNINIT_EXT | 4355 EXT4_GET_BLOCKS_NO_NORMALIZE; 4356 if (mode & FALLOC_FL_KEEP_SIZE) 4357 flags |= EXT4_GET_BLOCKS_KEEP_SIZE; 4358retry: 4359 while (ret >= 0 && ret < max_blocks) { 4360 map.m_lblk = map.m_lblk + ret; 4361 map.m_len = max_blocks = max_blocks - ret; 4362 handle = ext4_journal_start(inode, credits); 4363 if (IS_ERR(handle)) { 4364 ret = PTR_ERR(handle); 4365 break; 4366 } 4367 ret = ext4_map_blocks(handle, inode, &map, flags); 4368 if (ret <= 0) { 4369#ifdef EXT4FS_DEBUG 4370 WARN_ON(ret <= 0); 4371 printk(KERN_ERR "%s: ext4_ext_map_blocks " 4372 "returned error inode#%lu, block=%u, " 4373 "max_blocks=%u", __func__, 4374 inode->i_ino, map.m_lblk, max_blocks); 4375#endif 4376 ext4_mark_inode_dirty(handle, inode); 4377 ret2 = ext4_journal_stop(handle); 4378 break; 4379 } 4380 if ((map.m_lblk + ret) >= (EXT4_BLOCK_ALIGN(offset + len, 4381 blkbits) >> blkbits)) 4382 new_size = offset + len; 4383 else 4384 new_size = ((loff_t) map.m_lblk + ret) << blkbits; 4385 4386 ext4_falloc_update_inode(inode, mode, new_size, 4387 (map.m_flags & EXT4_MAP_NEW)); 4388 ext4_mark_inode_dirty(handle, inode); 4389 ret2 = ext4_journal_stop(handle); 4390 if (ret2) 4391 break; 4392 } 4393 if (ret == -ENOSPC && 4394 ext4_should_retry_alloc(inode->i_sb, &retries)) { 4395 ret = 0; 4396 goto retry; 4397 } 4398 mutex_unlock(&inode->i_mutex); 4399 trace_ext4_fallocate_exit(inode, offset, max_blocks, 4400 ret > 0 ? ret2 : ret); 4401 return ret > 0 ? ret2 : ret; 4402} 4403 4404/* 4405 * This function convert a range of blocks to written extents 4406 * The caller of this function will pass the start offset and the size. 4407 * all unwritten extents within this range will be converted to 4408 * written extents. 4409 * 4410 * This function is called from the direct IO end io call back 4411 * function, to convert the fallocated extents after IO is completed. 4412 * Returns 0 on success. 4413 */ 4414int ext4_convert_unwritten_extents(struct inode *inode, loff_t offset, 4415 ssize_t len) 4416{ 4417 handle_t *handle; 4418 unsigned int max_blocks; 4419 int ret = 0; 4420 int ret2 = 0; 4421 struct ext4_map_blocks map; 4422 unsigned int credits, blkbits = inode->i_blkbits; 4423 4424 map.m_lblk = offset >> blkbits; 4425 /* 4426 * We can't just convert len to max_blocks because 4427 * If blocksize = 4096 offset = 3072 and len = 2048 4428 */ 4429 max_blocks = ((EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits) - 4430 map.m_lblk); 4431 /* 4432 * credits to insert 1 extent into extent tree 4433 */ 4434 credits = ext4_chunk_trans_blocks(inode, max_blocks); 4435 while (ret >= 0 && ret < max_blocks) { 4436 map.m_lblk += ret; 4437 map.m_len = (max_blocks -= ret); 4438 handle = ext4_journal_start(inode, credits); 4439 if (IS_ERR(handle)) { 4440 ret = PTR_ERR(handle); 4441 break; 4442 } 4443 ret = ext4_map_blocks(handle, inode, &map, 4444 EXT4_GET_BLOCKS_IO_CONVERT_EXT); 4445 if (ret <= 0) { 4446 WARN_ON(ret <= 0); 4447 printk(KERN_ERR "%s: ext4_ext_map_blocks " 4448 "returned error inode#%lu, block=%u, " 4449 "max_blocks=%u", __func__, 4450 inode->i_ino, map.m_lblk, map.m_len); 4451 } 4452 ext4_mark_inode_dirty(handle, inode); 4453 ret2 = ext4_journal_stop(handle); 4454 if (ret <= 0 || ret2 ) 4455 break; 4456 } 4457 return ret > 0 ? ret2 : ret; 4458} 4459 4460/* 4461 * Callback function called for each extent to gather FIEMAP information. 4462 */ 4463static int ext4_ext_fiemap_cb(struct inode *inode, ext4_lblk_t next, 4464 struct ext4_ext_cache *newex, struct ext4_extent *ex, 4465 void *data) 4466{ 4467 __u64 logical; 4468 __u64 physical; 4469 __u64 length; 4470 __u32 flags = 0; 4471 int ret = 0; 4472 struct fiemap_extent_info *fieinfo = data; 4473 unsigned char blksize_bits; 4474 4475 blksize_bits = inode->i_sb->s_blocksize_bits; 4476 logical = (__u64)newex->ec_block << blksize_bits; 4477 4478 if (newex->ec_start == 0) { 4479 /* 4480 * No extent in extent-tree contains block @newex->ec_start, 4481 * then the block may stay in 1)a hole or 2)delayed-extent. 4482 * 4483 * Holes or delayed-extents are processed as follows. 4484 * 1. lookup dirty pages with specified range in pagecache. 4485 * If no page is got, then there is no delayed-extent and 4486 * return with EXT_CONTINUE. 4487 * 2. find the 1st mapped buffer, 4488 * 3. check if the mapped buffer is both in the request range 4489 * and a delayed buffer. If not, there is no delayed-extent, 4490 * then return. 4491 * 4. a delayed-extent is found, the extent will be collected. 4492 */ 4493 ext4_lblk_t end = 0; 4494 pgoff_t last_offset; 4495 pgoff_t offset; 4496 pgoff_t index; 4497 pgoff_t start_index = 0; 4498 struct page **pages = NULL; 4499 struct buffer_head *bh = NULL; 4500 struct buffer_head *head = NULL; 4501 unsigned int nr_pages = PAGE_SIZE / sizeof(struct page *); 4502 4503 pages = kmalloc(PAGE_SIZE, GFP_KERNEL); 4504 if (pages == NULL) 4505 return -ENOMEM; 4506 4507 offset = logical >> PAGE_SHIFT; 4508repeat: 4509 last_offset = offset; 4510 head = NULL; 4511 ret = find_get_pages_tag(inode->i_mapping, &offset, 4512 PAGECACHE_TAG_DIRTY, nr_pages, pages); 4513 4514 if (!(flags & FIEMAP_EXTENT_DELALLOC)) { 4515 /* First time, try to find a mapped buffer. */ 4516 if (ret == 0) { 4517out: 4518 for (index = 0; index < ret; index++) 4519 page_cache_release(pages[index]); 4520 /* just a hole. */ 4521 kfree(pages); 4522 return EXT_CONTINUE; 4523 } 4524 index = 0; 4525 4526next_page: 4527 /* Try to find the 1st mapped buffer. */ 4528 end = ((__u64)pages[index]->index << PAGE_SHIFT) >> 4529 blksize_bits; 4530 if (!page_has_buffers(pages[index])) 4531 goto out; 4532 head = page_buffers(pages[index]); 4533 if (!head) 4534 goto out; 4535 4536 index++; 4537 bh = head; 4538 do { 4539 if (end >= newex->ec_block + 4540 newex->ec_len) 4541 /* The buffer is out of 4542 * the request range. 4543 */ 4544 goto out; 4545 4546 if (buffer_mapped(bh) && 4547 end >= newex->ec_block) { 4548 start_index = index - 1; 4549 /* get the 1st mapped buffer. */ 4550 goto found_mapped_buffer; 4551 } 4552 4553 bh = bh->b_this_page; 4554 end++; 4555 } while (bh != head); 4556 4557 /* No mapped buffer in the range found in this page, 4558 * We need to look up next page. 4559 */ 4560 if (index >= ret) { 4561 /* There is no page left, but we need to limit 4562 * newex->ec_len. 4563 */ 4564 newex->ec_len = end - newex->ec_block; 4565 goto out; 4566 } 4567 goto next_page; 4568 } else { 4569 /*Find contiguous delayed buffers. */ 4570 if (ret > 0 && pages[0]->index == last_offset) 4571 head = page_buffers(pages[0]); 4572 bh = head; 4573 index = 1; 4574 start_index = 0; 4575 } 4576 4577found_mapped_buffer: 4578 if (bh != NULL && buffer_delay(bh)) { 4579 /* 1st or contiguous delayed buffer found. */ 4580 if (!(flags & FIEMAP_EXTENT_DELALLOC)) { 4581 /* 4582 * 1st delayed buffer found, record 4583 * the start of extent. 4584 */ 4585 flags |= FIEMAP_EXTENT_DELALLOC; 4586 newex->ec_block = end; 4587 logical = (__u64)end << blksize_bits; 4588 } 4589 /* Find contiguous delayed buffers. */ 4590 do { 4591 if (!buffer_delay(bh)) 4592 goto found_delayed_extent; 4593 bh = bh->b_this_page; 4594 end++; 4595 } while (bh != head); 4596 4597 for (; index < ret; index++) { 4598 if (!page_has_buffers(pages[index])) { 4599 bh = NULL; 4600 break; 4601 } 4602 head = page_buffers(pages[index]); 4603 if (!head) { 4604 bh = NULL; 4605 break; 4606 } 4607 4608 if (pages[index]->index != 4609 pages[start_index]->index + index 4610 - start_index) { 4611 /* Blocks are not contiguous. */ 4612 bh = NULL; 4613 break; 4614 } 4615 bh = head; 4616 do { 4617 if (!buffer_delay(bh)) 4618 /* Delayed-extent ends. */ 4619 goto found_delayed_extent; 4620 bh = bh->b_this_page; 4621 end++; 4622 } while (bh != head); 4623 } 4624 } else if (!(flags & FIEMAP_EXTENT_DELALLOC)) 4625 /* a hole found. */ 4626 goto out; 4627 4628found_delayed_extent: 4629 newex->ec_len = min(end - newex->ec_block, 4630 (ext4_lblk_t)EXT_INIT_MAX_LEN); 4631 if (ret == nr_pages && bh != NULL && 4632 newex->ec_len < EXT_INIT_MAX_LEN && 4633 buffer_delay(bh)) { 4634 /* Have not collected an extent and continue. */ 4635 for (index = 0; index < ret; index++) 4636 page_cache_release(pages[index]); 4637 goto repeat; 4638 } 4639 4640 for (index = 0; index < ret; index++) 4641 page_cache_release(pages[index]); 4642 kfree(pages); 4643 } 4644 4645 physical = (__u64)newex->ec_start << blksize_bits; 4646 length = (__u64)newex->ec_len << blksize_bits; 4647 4648 if (ex && ext4_ext_is_uninitialized(ex)) 4649 flags |= FIEMAP_EXTENT_UNWRITTEN; 4650 4651 if (next == EXT_MAX_BLOCKS) 4652 flags |= FIEMAP_EXTENT_LAST; 4653 4654 ret = fiemap_fill_next_extent(fieinfo, logical, physical, 4655 length, flags); 4656 if (ret < 0) 4657 return ret; 4658 if (ret == 1) 4659 return EXT_BREAK; 4660 return EXT_CONTINUE; 4661} 4662/* fiemap flags we can handle specified here */ 4663#define EXT4_FIEMAP_FLAGS (FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR) 4664 4665static int ext4_xattr_fiemap(struct inode *inode, 4666 struct fiemap_extent_info *fieinfo) 4667{ 4668 __u64 physical = 0; 4669 __u64 length; 4670 __u32 flags = FIEMAP_EXTENT_LAST; 4671 int blockbits = inode->i_sb->s_blocksize_bits; 4672 int error = 0; 4673 4674 /* in-inode? */ 4675 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) { 4676 struct ext4_iloc iloc; 4677 int offset; /* offset of xattr in inode */ 4678 4679 error = ext4_get_inode_loc(inode, &iloc); 4680 if (error) 4681 return error; 4682 physical = iloc.bh->b_blocknr << blockbits; 4683 offset = EXT4_GOOD_OLD_INODE_SIZE + 4684 EXT4_I(inode)->i_extra_isize; 4685 physical += offset; 4686 length = EXT4_SB(inode->i_sb)->s_inode_size - offset; 4687 flags |= FIEMAP_EXTENT_DATA_INLINE; 4688 brelse(iloc.bh); 4689 } else { /* external block */ 4690 physical = EXT4_I(inode)->i_file_acl << blockbits; 4691 length = inode->i_sb->s_blocksize; 4692 } 4693 4694 if (physical) 4695 error = fiemap_fill_next_extent(fieinfo, 0, physical, 4696 length, flags); 4697 return (error < 0 ? error : 0); 4698} 4699 4700/* 4701 * ext4_ext_punch_hole 4702 * 4703 * Punches a hole of "length" bytes in a file starting 4704 * at byte "offset" 4705 * 4706 * @inode: The inode of the file to punch a hole in 4707 * @offset: The starting byte offset of the hole 4708 * @length: The length of the hole 4709 * 4710 * Returns the number of blocks removed or negative on err 4711 */ 4712int ext4_ext_punch_hole(struct file *file, loff_t offset, loff_t length) 4713{ 4714 struct inode *inode = file->f_path.dentry->d_inode; 4715 struct super_block *sb = inode->i_sb; 4716 struct ext4_ext_cache cache_ex; 4717 ext4_lblk_t first_block, last_block, num_blocks, iblock, max_blocks; 4718 struct address_space *mapping = inode->i_mapping; 4719 struct ext4_map_blocks map; 4720 handle_t *handle; 4721 loff_t first_page, last_page, page_len; 4722 loff_t first_page_offset, last_page_offset; 4723 int ret, credits, blocks_released, err = 0; 4724 4725 /* No need to punch hole beyond i_size */ 4726 if (offset >= inode->i_size) 4727 return 0; 4728 4729 /* 4730 * If the hole extends beyond i_size, set the hole 4731 * to end after the page that contains i_size 4732 */ 4733 if (offset + length > inode->i_size) { 4734 length = inode->i_size + 4735 PAGE_CACHE_SIZE - (inode->i_size & (PAGE_CACHE_SIZE - 1)) - 4736 offset; 4737 } 4738 4739 first_block = (offset + sb->s_blocksize - 1) >> 4740 EXT4_BLOCK_SIZE_BITS(sb); 4741 last_block = (offset + length) >> EXT4_BLOCK_SIZE_BITS(sb); 4742 4743 first_page = (offset + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 4744 last_page = (offset + length) >> PAGE_CACHE_SHIFT; 4745 4746 first_page_offset = first_page << PAGE_CACHE_SHIFT; 4747 last_page_offset = last_page << PAGE_CACHE_SHIFT; 4748 4749 /* 4750 * Write out all dirty pages to avoid race conditions 4751 * Then release them. 4752 */ 4753 if (mapping->nrpages && mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) { 4754 err = filemap_write_and_wait_range(mapping, 4755 offset, offset + length - 1); 4756 4757 if (err) 4758 return err; 4759 } 4760 4761 /* Now release the pages */ 4762 if (last_page_offset > first_page_offset) { 4763 truncate_inode_pages_range(mapping, first_page_offset, 4764 last_page_offset-1); 4765 } 4766 4767 /* finish any pending end_io work */ 4768 ext4_flush_completed_IO(inode); 4769 4770 credits = ext4_writepage_trans_blocks(inode); 4771 handle = ext4_journal_start(inode, credits); 4772 if (IS_ERR(handle)) 4773 return PTR_ERR(handle); 4774 4775 err = ext4_orphan_add(handle, inode); 4776 if (err) 4777 goto out; 4778 4779 /* 4780 * Now we need to zero out the non-page-aligned data in the 4781 * pages at the start and tail of the hole, and unmap the buffer 4782 * heads for the block aligned regions of the page that were 4783 * completely zeroed. 4784 */ 4785 if (first_page > last_page) { 4786 /* 4787 * If the file space being truncated is contained within a page 4788 * just zero out and unmap the middle of that page 4789 */ 4790 err = ext4_discard_partial_page_buffers(handle, 4791 mapping, offset, length, 0); 4792 4793 if (err) 4794 goto out; 4795 } else { 4796 /* 4797 * zero out and unmap the partial page that contains 4798 * the start of the hole 4799 */ 4800 page_len = first_page_offset - offset; 4801 if (page_len > 0) { 4802 err = ext4_discard_partial_page_buffers(handle, mapping, 4803 offset, page_len, 0); 4804 if (err) 4805 goto out; 4806 } 4807 4808 /* 4809 * zero out and unmap the partial page that contains 4810 * the end of the hole 4811 */ 4812 page_len = offset + length - last_page_offset; 4813 if (page_len > 0) { 4814 err = ext4_discard_partial_page_buffers(handle, mapping, 4815 last_page_offset, page_len, 0); 4816 if (err) 4817 goto out; 4818 } 4819 } 4820 4821 4822 /* 4823 * If i_size is contained in the last page, we need to 4824 * unmap and zero the partial page after i_size 4825 */ 4826 if (inode->i_size >> PAGE_CACHE_SHIFT == last_page && 4827 inode->i_size % PAGE_CACHE_SIZE != 0) { 4828 4829 page_len = PAGE_CACHE_SIZE - 4830 (inode->i_size & (PAGE_CACHE_SIZE - 1)); 4831 4832 if (page_len > 0) { 4833 err = ext4_discard_partial_page_buffers(handle, 4834 mapping, inode->i_size, page_len, 0); 4835 4836 if (err) 4837 goto out; 4838 } 4839 } 4840 4841 /* If there are no blocks to remove, return now */ 4842 if (first_block >= last_block) 4843 goto out; 4844 4845 down_write(&EXT4_I(inode)->i_data_sem); 4846 ext4_ext_invalidate_cache(inode); 4847 ext4_discard_preallocations(inode); 4848 4849 /* 4850 * Loop over all the blocks and identify blocks 4851 * that need to be punched out 4852 */ 4853 iblock = first_block; 4854 blocks_released = 0; 4855 while (iblock < last_block) { 4856 max_blocks = last_block - iblock; 4857 num_blocks = 1; 4858 memset(&map, 0, sizeof(map)); 4859 map.m_lblk = iblock; 4860 map.m_len = max_blocks; 4861 ret = ext4_ext_map_blocks(handle, inode, &map, 4862 EXT4_GET_BLOCKS_PUNCH_OUT_EXT); 4863 4864 if (ret > 0) { 4865 blocks_released += ret; 4866 num_blocks = ret; 4867 } else if (ret == 0) { 4868 /* 4869 * If map blocks could not find the block, 4870 * then it is in a hole. If the hole was 4871 * not already cached, then map blocks should 4872 * put it in the cache. So we can get the hole 4873 * out of the cache 4874 */ 4875 memset(&cache_ex, 0, sizeof(cache_ex)); 4876 if ((ext4_ext_check_cache(inode, iblock, &cache_ex)) && 4877 !cache_ex.ec_start) { 4878 4879 /* The hole is cached */ 4880 num_blocks = cache_ex.ec_block + 4881 cache_ex.ec_len - iblock; 4882 4883 } else { 4884 /* The block could not be identified */ 4885 err = -EIO; 4886 break; 4887 } 4888 } else { 4889 /* Map blocks error */ 4890 err = ret; 4891 break; 4892 } 4893 4894 if (num_blocks == 0) { 4895 /* This condition should never happen */ 4896 ext_debug("Block lookup failed"); 4897 err = -EIO; 4898 break; 4899 } 4900 4901 iblock += num_blocks; 4902 } 4903 4904 if (blocks_released > 0) { 4905 ext4_ext_invalidate_cache(inode); 4906 ext4_discard_preallocations(inode); 4907 } 4908 4909 if (IS_SYNC(inode)) 4910 ext4_handle_sync(handle); 4911 4912 up_write(&EXT4_I(inode)->i_data_sem); 4913 4914out: 4915 ext4_orphan_del(handle, inode); 4916 inode->i_mtime = inode->i_ctime = ext4_current_time(inode); 4917 ext4_mark_inode_dirty(handle, inode); 4918 ext4_journal_stop(handle); 4919 return err; 4920} 4921int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, 4922 __u64 start, __u64 len) 4923{ 4924 ext4_lblk_t start_blk; 4925 int error = 0; 4926 4927 /* fallback to generic here if not in extents fmt */ 4928 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) 4929 return generic_block_fiemap(inode, fieinfo, start, len, 4930 ext4_get_block); 4931 4932 if (fiemap_check_flags(fieinfo, EXT4_FIEMAP_FLAGS)) 4933 return -EBADR; 4934 4935 if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) { 4936 error = ext4_xattr_fiemap(inode, fieinfo); 4937 } else { 4938 ext4_lblk_t len_blks; 4939 __u64 last_blk; 4940 4941 start_blk = start >> inode->i_sb->s_blocksize_bits; 4942 last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits; 4943 if (last_blk >= EXT_MAX_BLOCKS) 4944 last_blk = EXT_MAX_BLOCKS-1; 4945 len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1; 4946 4947 /* 4948 * Walk the extent tree gathering extent information. 4949 * ext4_ext_fiemap_cb will push extents back to user. 4950 */ 4951 error = ext4_ext_walk_space(inode, start_blk, len_blks, 4952 ext4_ext_fiemap_cb, fieinfo); 4953 } 4954 4955 return error; 4956} 4957