extents.c revision ecb94f5fdf4b72547fca022421a9dca1672bddd4
1/* 2 * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com 3 * Written by Alex Tomas <alex@clusterfs.com> 4 * 5 * Architecture independence: 6 * Copyright (c) 2005, Bull S.A. 7 * Written by Pierre Peiffer <pierre.peiffer@bull.net> 8 * 9 * This program is free software; you can redistribute it and/or modify 10 * it under the terms of the GNU General Public License version 2 as 11 * published by the Free Software Foundation. 12 * 13 * This program is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 * GNU General Public License for more details. 17 * 18 * You should have received a copy of the GNU General Public Licens 19 * along with this program; if not, write to the Free Software 20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111- 21 */ 22 23/* 24 * Extents support for EXT4 25 * 26 * TODO: 27 * - ext4*_error() should be used in some situations 28 * - analyze all BUG()/BUG_ON(), use -EIO where appropriate 29 * - smart tree reduction 30 */ 31 32#include <linux/fs.h> 33#include <linux/time.h> 34#include <linux/jbd2.h> 35#include <linux/highuid.h> 36#include <linux/pagemap.h> 37#include <linux/quotaops.h> 38#include <linux/string.h> 39#include <linux/slab.h> 40#include <linux/falloc.h> 41#include <asm/uaccess.h> 42#include <linux/fiemap.h> 43#include "ext4_jbd2.h" 44 45#include <trace/events/ext4.h> 46 47/* 48 * used by extent splitting. 49 */ 50#define EXT4_EXT_MAY_ZEROOUT 0x1 /* safe to zeroout if split fails \ 51 due to ENOSPC */ 52#define EXT4_EXT_MARK_UNINIT1 0x2 /* mark first half uninitialized */ 53#define EXT4_EXT_MARK_UNINIT2 0x4 /* mark second half uninitialized */ 54 55static __le32 ext4_extent_block_csum(struct inode *inode, 56 struct ext4_extent_header *eh) 57{ 58 struct ext4_inode_info *ei = EXT4_I(inode); 59 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 60 __u32 csum; 61 62 csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)eh, 63 EXT4_EXTENT_TAIL_OFFSET(eh)); 64 return cpu_to_le32(csum); 65} 66 67static int ext4_extent_block_csum_verify(struct inode *inode, 68 struct ext4_extent_header *eh) 69{ 70 struct ext4_extent_tail *et; 71 72 if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb, 73 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) 74 return 1; 75 76 et = find_ext4_extent_tail(eh); 77 if (et->et_checksum != ext4_extent_block_csum(inode, eh)) 78 return 0; 79 return 1; 80} 81 82static void ext4_extent_block_csum_set(struct inode *inode, 83 struct ext4_extent_header *eh) 84{ 85 struct ext4_extent_tail *et; 86 87 if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb, 88 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) 89 return; 90 91 et = find_ext4_extent_tail(eh); 92 et->et_checksum = ext4_extent_block_csum(inode, eh); 93} 94 95static int ext4_split_extent(handle_t *handle, 96 struct inode *inode, 97 struct ext4_ext_path *path, 98 struct ext4_map_blocks *map, 99 int split_flag, 100 int flags); 101 102static int ext4_split_extent_at(handle_t *handle, 103 struct inode *inode, 104 struct ext4_ext_path *path, 105 ext4_lblk_t split, 106 int split_flag, 107 int flags); 108 109static int ext4_ext_truncate_extend_restart(handle_t *handle, 110 struct inode *inode, 111 int needed) 112{ 113 int err; 114 115 if (!ext4_handle_valid(handle)) 116 return 0; 117 if (handle->h_buffer_credits > needed) 118 return 0; 119 err = ext4_journal_extend(handle, needed); 120 if (err <= 0) 121 return err; 122 err = ext4_truncate_restart_trans(handle, inode, needed); 123 if (err == 0) 124 err = -EAGAIN; 125 126 return err; 127} 128 129/* 130 * could return: 131 * - EROFS 132 * - ENOMEM 133 */ 134static int ext4_ext_get_access(handle_t *handle, struct inode *inode, 135 struct ext4_ext_path *path) 136{ 137 if (path->p_bh) { 138 /* path points to block */ 139 return ext4_journal_get_write_access(handle, path->p_bh); 140 } 141 /* path points to leaf/index in inode body */ 142 /* we use in-core data, no need to protect them */ 143 return 0; 144} 145 146/* 147 * could return: 148 * - EROFS 149 * - ENOMEM 150 * - EIO 151 */ 152#define ext4_ext_dirty(handle, inode, path) \ 153 __ext4_ext_dirty(__func__, __LINE__, (handle), (inode), (path)) 154static int __ext4_ext_dirty(const char *where, unsigned int line, 155 handle_t *handle, struct inode *inode, 156 struct ext4_ext_path *path) 157{ 158 int err; 159 if (path->p_bh) { 160 ext4_extent_block_csum_set(inode, ext_block_hdr(path->p_bh)); 161 /* path points to block */ 162 err = __ext4_handle_dirty_metadata(where, line, handle, 163 inode, path->p_bh); 164 } else { 165 /* path points to leaf/index in inode body */ 166 err = ext4_mark_inode_dirty(handle, inode); 167 } 168 return err; 169} 170 171static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode, 172 struct ext4_ext_path *path, 173 ext4_lblk_t block) 174{ 175 if (path) { 176 int depth = path->p_depth; 177 struct ext4_extent *ex; 178 179 /* 180 * Try to predict block placement assuming that we are 181 * filling in a file which will eventually be 182 * non-sparse --- i.e., in the case of libbfd writing 183 * an ELF object sections out-of-order but in a way 184 * the eventually results in a contiguous object or 185 * executable file, or some database extending a table 186 * space file. However, this is actually somewhat 187 * non-ideal if we are writing a sparse file such as 188 * qemu or KVM writing a raw image file that is going 189 * to stay fairly sparse, since it will end up 190 * fragmenting the file system's free space. Maybe we 191 * should have some hueristics or some way to allow 192 * userspace to pass a hint to file system, 193 * especially if the latter case turns out to be 194 * common. 195 */ 196 ex = path[depth].p_ext; 197 if (ex) { 198 ext4_fsblk_t ext_pblk = ext4_ext_pblock(ex); 199 ext4_lblk_t ext_block = le32_to_cpu(ex->ee_block); 200 201 if (block > ext_block) 202 return ext_pblk + (block - ext_block); 203 else 204 return ext_pblk - (ext_block - block); 205 } 206 207 /* it looks like index is empty; 208 * try to find starting block from index itself */ 209 if (path[depth].p_bh) 210 return path[depth].p_bh->b_blocknr; 211 } 212 213 /* OK. use inode's group */ 214 return ext4_inode_to_goal_block(inode); 215} 216 217/* 218 * Allocation for a meta data block 219 */ 220static ext4_fsblk_t 221ext4_ext_new_meta_block(handle_t *handle, struct inode *inode, 222 struct ext4_ext_path *path, 223 struct ext4_extent *ex, int *err, unsigned int flags) 224{ 225 ext4_fsblk_t goal, newblock; 226 227 goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block)); 228 newblock = ext4_new_meta_blocks(handle, inode, goal, flags, 229 NULL, err); 230 return newblock; 231} 232 233static inline int ext4_ext_space_block(struct inode *inode, int check) 234{ 235 int size; 236 237 size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header)) 238 / sizeof(struct ext4_extent); 239#ifdef AGGRESSIVE_TEST 240 if (!check && size > 6) 241 size = 6; 242#endif 243 return size; 244} 245 246static inline int ext4_ext_space_block_idx(struct inode *inode, int check) 247{ 248 int size; 249 250 size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header)) 251 / sizeof(struct ext4_extent_idx); 252#ifdef AGGRESSIVE_TEST 253 if (!check && size > 5) 254 size = 5; 255#endif 256 return size; 257} 258 259static inline int ext4_ext_space_root(struct inode *inode, int check) 260{ 261 int size; 262 263 size = sizeof(EXT4_I(inode)->i_data); 264 size -= sizeof(struct ext4_extent_header); 265 size /= sizeof(struct ext4_extent); 266#ifdef AGGRESSIVE_TEST 267 if (!check && size > 3) 268 size = 3; 269#endif 270 return size; 271} 272 273static inline int ext4_ext_space_root_idx(struct inode *inode, int check) 274{ 275 int size; 276 277 size = sizeof(EXT4_I(inode)->i_data); 278 size -= sizeof(struct ext4_extent_header); 279 size /= sizeof(struct ext4_extent_idx); 280#ifdef AGGRESSIVE_TEST 281 if (!check && size > 4) 282 size = 4; 283#endif 284 return size; 285} 286 287/* 288 * Calculate the number of metadata blocks needed 289 * to allocate @blocks 290 * Worse case is one block per extent 291 */ 292int ext4_ext_calc_metadata_amount(struct inode *inode, ext4_lblk_t lblock) 293{ 294 struct ext4_inode_info *ei = EXT4_I(inode); 295 int idxs; 296 297 idxs = ((inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header)) 298 / sizeof(struct ext4_extent_idx)); 299 300 /* 301 * If the new delayed allocation block is contiguous with the 302 * previous da block, it can share index blocks with the 303 * previous block, so we only need to allocate a new index 304 * block every idxs leaf blocks. At ldxs**2 blocks, we need 305 * an additional index block, and at ldxs**3 blocks, yet 306 * another index blocks. 307 */ 308 if (ei->i_da_metadata_calc_len && 309 ei->i_da_metadata_calc_last_lblock+1 == lblock) { 310 int num = 0; 311 312 if ((ei->i_da_metadata_calc_len % idxs) == 0) 313 num++; 314 if ((ei->i_da_metadata_calc_len % (idxs*idxs)) == 0) 315 num++; 316 if ((ei->i_da_metadata_calc_len % (idxs*idxs*idxs)) == 0) { 317 num++; 318 ei->i_da_metadata_calc_len = 0; 319 } else 320 ei->i_da_metadata_calc_len++; 321 ei->i_da_metadata_calc_last_lblock++; 322 return num; 323 } 324 325 /* 326 * In the worst case we need a new set of index blocks at 327 * every level of the inode's extent tree. 328 */ 329 ei->i_da_metadata_calc_len = 1; 330 ei->i_da_metadata_calc_last_lblock = lblock; 331 return ext_depth(inode) + 1; 332} 333 334static int 335ext4_ext_max_entries(struct inode *inode, int depth) 336{ 337 int max; 338 339 if (depth == ext_depth(inode)) { 340 if (depth == 0) 341 max = ext4_ext_space_root(inode, 1); 342 else 343 max = ext4_ext_space_root_idx(inode, 1); 344 } else { 345 if (depth == 0) 346 max = ext4_ext_space_block(inode, 1); 347 else 348 max = ext4_ext_space_block_idx(inode, 1); 349 } 350 351 return max; 352} 353 354static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext) 355{ 356 ext4_fsblk_t block = ext4_ext_pblock(ext); 357 int len = ext4_ext_get_actual_len(ext); 358 359 if (len == 0) 360 return 0; 361 return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, len); 362} 363 364static int ext4_valid_extent_idx(struct inode *inode, 365 struct ext4_extent_idx *ext_idx) 366{ 367 ext4_fsblk_t block = ext4_idx_pblock(ext_idx); 368 369 return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, 1); 370} 371 372static int ext4_valid_extent_entries(struct inode *inode, 373 struct ext4_extent_header *eh, 374 int depth) 375{ 376 unsigned short entries; 377 if (eh->eh_entries == 0) 378 return 1; 379 380 entries = le16_to_cpu(eh->eh_entries); 381 382 if (depth == 0) { 383 /* leaf entries */ 384 struct ext4_extent *ext = EXT_FIRST_EXTENT(eh); 385 while (entries) { 386 if (!ext4_valid_extent(inode, ext)) 387 return 0; 388 ext++; 389 entries--; 390 } 391 } else { 392 struct ext4_extent_idx *ext_idx = EXT_FIRST_INDEX(eh); 393 while (entries) { 394 if (!ext4_valid_extent_idx(inode, ext_idx)) 395 return 0; 396 ext_idx++; 397 entries--; 398 } 399 } 400 return 1; 401} 402 403static int __ext4_ext_check(const char *function, unsigned int line, 404 struct inode *inode, struct ext4_extent_header *eh, 405 int depth) 406{ 407 const char *error_msg; 408 int max = 0; 409 410 if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) { 411 error_msg = "invalid magic"; 412 goto corrupted; 413 } 414 if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) { 415 error_msg = "unexpected eh_depth"; 416 goto corrupted; 417 } 418 if (unlikely(eh->eh_max == 0)) { 419 error_msg = "invalid eh_max"; 420 goto corrupted; 421 } 422 max = ext4_ext_max_entries(inode, depth); 423 if (unlikely(le16_to_cpu(eh->eh_max) > max)) { 424 error_msg = "too large eh_max"; 425 goto corrupted; 426 } 427 if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) { 428 error_msg = "invalid eh_entries"; 429 goto corrupted; 430 } 431 if (!ext4_valid_extent_entries(inode, eh, depth)) { 432 error_msg = "invalid extent entries"; 433 goto corrupted; 434 } 435 /* Verify checksum on non-root extent tree nodes */ 436 if (ext_depth(inode) != depth && 437 !ext4_extent_block_csum_verify(inode, eh)) { 438 error_msg = "extent tree corrupted"; 439 goto corrupted; 440 } 441 return 0; 442 443corrupted: 444 ext4_error_inode(inode, function, line, 0, 445 "bad header/extent: %s - magic %x, " 446 "entries %u, max %u(%u), depth %u(%u)", 447 error_msg, le16_to_cpu(eh->eh_magic), 448 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max), 449 max, le16_to_cpu(eh->eh_depth), depth); 450 451 return -EIO; 452} 453 454#define ext4_ext_check(inode, eh, depth) \ 455 __ext4_ext_check(__func__, __LINE__, inode, eh, depth) 456 457int ext4_ext_check_inode(struct inode *inode) 458{ 459 return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode)); 460} 461 462static int __ext4_ext_check_block(const char *function, unsigned int line, 463 struct inode *inode, 464 struct ext4_extent_header *eh, 465 int depth, 466 struct buffer_head *bh) 467{ 468 int ret; 469 470 if (buffer_verified(bh)) 471 return 0; 472 ret = ext4_ext_check(inode, eh, depth); 473 if (ret) 474 return ret; 475 set_buffer_verified(bh); 476 return ret; 477} 478 479#define ext4_ext_check_block(inode, eh, depth, bh) \ 480 __ext4_ext_check_block(__func__, __LINE__, inode, eh, depth, bh) 481 482#ifdef EXT_DEBUG 483static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path) 484{ 485 int k, l = path->p_depth; 486 487 ext_debug("path:"); 488 for (k = 0; k <= l; k++, path++) { 489 if (path->p_idx) { 490 ext_debug(" %d->%llu", le32_to_cpu(path->p_idx->ei_block), 491 ext4_idx_pblock(path->p_idx)); 492 } else if (path->p_ext) { 493 ext_debug(" %d:[%d]%d:%llu ", 494 le32_to_cpu(path->p_ext->ee_block), 495 ext4_ext_is_uninitialized(path->p_ext), 496 ext4_ext_get_actual_len(path->p_ext), 497 ext4_ext_pblock(path->p_ext)); 498 } else 499 ext_debug(" []"); 500 } 501 ext_debug("\n"); 502} 503 504static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path) 505{ 506 int depth = ext_depth(inode); 507 struct ext4_extent_header *eh; 508 struct ext4_extent *ex; 509 int i; 510 511 if (!path) 512 return; 513 514 eh = path[depth].p_hdr; 515 ex = EXT_FIRST_EXTENT(eh); 516 517 ext_debug("Displaying leaf extents for inode %lu\n", inode->i_ino); 518 519 for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) { 520 ext_debug("%d:[%d]%d:%llu ", le32_to_cpu(ex->ee_block), 521 ext4_ext_is_uninitialized(ex), 522 ext4_ext_get_actual_len(ex), ext4_ext_pblock(ex)); 523 } 524 ext_debug("\n"); 525} 526 527static void ext4_ext_show_move(struct inode *inode, struct ext4_ext_path *path, 528 ext4_fsblk_t newblock, int level) 529{ 530 int depth = ext_depth(inode); 531 struct ext4_extent *ex; 532 533 if (depth != level) { 534 struct ext4_extent_idx *idx; 535 idx = path[level].p_idx; 536 while (idx <= EXT_MAX_INDEX(path[level].p_hdr)) { 537 ext_debug("%d: move %d:%llu in new index %llu\n", level, 538 le32_to_cpu(idx->ei_block), 539 ext4_idx_pblock(idx), 540 newblock); 541 idx++; 542 } 543 544 return; 545 } 546 547 ex = path[depth].p_ext; 548 while (ex <= EXT_MAX_EXTENT(path[depth].p_hdr)) { 549 ext_debug("move %d:%llu:[%d]%d in new leaf %llu\n", 550 le32_to_cpu(ex->ee_block), 551 ext4_ext_pblock(ex), 552 ext4_ext_is_uninitialized(ex), 553 ext4_ext_get_actual_len(ex), 554 newblock); 555 ex++; 556 } 557} 558 559#else 560#define ext4_ext_show_path(inode, path) 561#define ext4_ext_show_leaf(inode, path) 562#define ext4_ext_show_move(inode, path, newblock, level) 563#endif 564 565void ext4_ext_drop_refs(struct ext4_ext_path *path) 566{ 567 int depth = path->p_depth; 568 int i; 569 570 for (i = 0; i <= depth; i++, path++) 571 if (path->p_bh) { 572 brelse(path->p_bh); 573 path->p_bh = NULL; 574 } 575} 576 577/* 578 * ext4_ext_binsearch_idx: 579 * binary search for the closest index of the given block 580 * the header must be checked before calling this 581 */ 582static void 583ext4_ext_binsearch_idx(struct inode *inode, 584 struct ext4_ext_path *path, ext4_lblk_t block) 585{ 586 struct ext4_extent_header *eh = path->p_hdr; 587 struct ext4_extent_idx *r, *l, *m; 588 589 590 ext_debug("binsearch for %u(idx): ", block); 591 592 l = EXT_FIRST_INDEX(eh) + 1; 593 r = EXT_LAST_INDEX(eh); 594 while (l <= r) { 595 m = l + (r - l) / 2; 596 if (block < le32_to_cpu(m->ei_block)) 597 r = m - 1; 598 else 599 l = m + 1; 600 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ei_block), 601 m, le32_to_cpu(m->ei_block), 602 r, le32_to_cpu(r->ei_block)); 603 } 604 605 path->p_idx = l - 1; 606 ext_debug(" -> %u->%lld ", le32_to_cpu(path->p_idx->ei_block), 607 ext4_idx_pblock(path->p_idx)); 608 609#ifdef CHECK_BINSEARCH 610 { 611 struct ext4_extent_idx *chix, *ix; 612 int k; 613 614 chix = ix = EXT_FIRST_INDEX(eh); 615 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) { 616 if (k != 0 && 617 le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) { 618 printk(KERN_DEBUG "k=%d, ix=0x%p, " 619 "first=0x%p\n", k, 620 ix, EXT_FIRST_INDEX(eh)); 621 printk(KERN_DEBUG "%u <= %u\n", 622 le32_to_cpu(ix->ei_block), 623 le32_to_cpu(ix[-1].ei_block)); 624 } 625 BUG_ON(k && le32_to_cpu(ix->ei_block) 626 <= le32_to_cpu(ix[-1].ei_block)); 627 if (block < le32_to_cpu(ix->ei_block)) 628 break; 629 chix = ix; 630 } 631 BUG_ON(chix != path->p_idx); 632 } 633#endif 634 635} 636 637/* 638 * ext4_ext_binsearch: 639 * binary search for closest extent of the given block 640 * the header must be checked before calling this 641 */ 642static void 643ext4_ext_binsearch(struct inode *inode, 644 struct ext4_ext_path *path, ext4_lblk_t block) 645{ 646 struct ext4_extent_header *eh = path->p_hdr; 647 struct ext4_extent *r, *l, *m; 648 649 if (eh->eh_entries == 0) { 650 /* 651 * this leaf is empty: 652 * we get such a leaf in split/add case 653 */ 654 return; 655 } 656 657 ext_debug("binsearch for %u: ", block); 658 659 l = EXT_FIRST_EXTENT(eh) + 1; 660 r = EXT_LAST_EXTENT(eh); 661 662 while (l <= r) { 663 m = l + (r - l) / 2; 664 if (block < le32_to_cpu(m->ee_block)) 665 r = m - 1; 666 else 667 l = m + 1; 668 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ee_block), 669 m, le32_to_cpu(m->ee_block), 670 r, le32_to_cpu(r->ee_block)); 671 } 672 673 path->p_ext = l - 1; 674 ext_debug(" -> %d:%llu:[%d]%d ", 675 le32_to_cpu(path->p_ext->ee_block), 676 ext4_ext_pblock(path->p_ext), 677 ext4_ext_is_uninitialized(path->p_ext), 678 ext4_ext_get_actual_len(path->p_ext)); 679 680#ifdef CHECK_BINSEARCH 681 { 682 struct ext4_extent *chex, *ex; 683 int k; 684 685 chex = ex = EXT_FIRST_EXTENT(eh); 686 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) { 687 BUG_ON(k && le32_to_cpu(ex->ee_block) 688 <= le32_to_cpu(ex[-1].ee_block)); 689 if (block < le32_to_cpu(ex->ee_block)) 690 break; 691 chex = ex; 692 } 693 BUG_ON(chex != path->p_ext); 694 } 695#endif 696 697} 698 699int ext4_ext_tree_init(handle_t *handle, struct inode *inode) 700{ 701 struct ext4_extent_header *eh; 702 703 eh = ext_inode_hdr(inode); 704 eh->eh_depth = 0; 705 eh->eh_entries = 0; 706 eh->eh_magic = EXT4_EXT_MAGIC; 707 eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode, 0)); 708 ext4_mark_inode_dirty(handle, inode); 709 ext4_ext_invalidate_cache(inode); 710 return 0; 711} 712 713struct ext4_ext_path * 714ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block, 715 struct ext4_ext_path *path) 716{ 717 struct ext4_extent_header *eh; 718 struct buffer_head *bh; 719 short int depth, i, ppos = 0, alloc = 0; 720 721 eh = ext_inode_hdr(inode); 722 depth = ext_depth(inode); 723 724 /* account possible depth increase */ 725 if (!path) { 726 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2), 727 GFP_NOFS); 728 if (!path) 729 return ERR_PTR(-ENOMEM); 730 alloc = 1; 731 } 732 path[0].p_hdr = eh; 733 path[0].p_bh = NULL; 734 735 i = depth; 736 /* walk through the tree */ 737 while (i) { 738 ext_debug("depth %d: num %d, max %d\n", 739 ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max)); 740 741 ext4_ext_binsearch_idx(inode, path + ppos, block); 742 path[ppos].p_block = ext4_idx_pblock(path[ppos].p_idx); 743 path[ppos].p_depth = i; 744 path[ppos].p_ext = NULL; 745 746 bh = sb_getblk(inode->i_sb, path[ppos].p_block); 747 if (unlikely(!bh)) 748 goto err; 749 if (!bh_uptodate_or_lock(bh)) { 750 trace_ext4_ext_load_extent(inode, block, 751 path[ppos].p_block); 752 if (bh_submit_read(bh) < 0) { 753 put_bh(bh); 754 goto err; 755 } 756 } 757 eh = ext_block_hdr(bh); 758 ppos++; 759 if (unlikely(ppos > depth)) { 760 put_bh(bh); 761 EXT4_ERROR_INODE(inode, 762 "ppos %d > depth %d", ppos, depth); 763 goto err; 764 } 765 path[ppos].p_bh = bh; 766 path[ppos].p_hdr = eh; 767 i--; 768 769 if (ext4_ext_check_block(inode, eh, i, bh)) 770 goto err; 771 } 772 773 path[ppos].p_depth = i; 774 path[ppos].p_ext = NULL; 775 path[ppos].p_idx = NULL; 776 777 /* find extent */ 778 ext4_ext_binsearch(inode, path + ppos, block); 779 /* if not an empty leaf */ 780 if (path[ppos].p_ext) 781 path[ppos].p_block = ext4_ext_pblock(path[ppos].p_ext); 782 783 ext4_ext_show_path(inode, path); 784 785 return path; 786 787err: 788 ext4_ext_drop_refs(path); 789 if (alloc) 790 kfree(path); 791 return ERR_PTR(-EIO); 792} 793 794/* 795 * ext4_ext_insert_index: 796 * insert new index [@logical;@ptr] into the block at @curp; 797 * check where to insert: before @curp or after @curp 798 */ 799static int ext4_ext_insert_index(handle_t *handle, struct inode *inode, 800 struct ext4_ext_path *curp, 801 int logical, ext4_fsblk_t ptr) 802{ 803 struct ext4_extent_idx *ix; 804 int len, err; 805 806 err = ext4_ext_get_access(handle, inode, curp); 807 if (err) 808 return err; 809 810 if (unlikely(logical == le32_to_cpu(curp->p_idx->ei_block))) { 811 EXT4_ERROR_INODE(inode, 812 "logical %d == ei_block %d!", 813 logical, le32_to_cpu(curp->p_idx->ei_block)); 814 return -EIO; 815 } 816 817 if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries) 818 >= le16_to_cpu(curp->p_hdr->eh_max))) { 819 EXT4_ERROR_INODE(inode, 820 "eh_entries %d >= eh_max %d!", 821 le16_to_cpu(curp->p_hdr->eh_entries), 822 le16_to_cpu(curp->p_hdr->eh_max)); 823 return -EIO; 824 } 825 826 if (logical > le32_to_cpu(curp->p_idx->ei_block)) { 827 /* insert after */ 828 ext_debug("insert new index %d after: %llu\n", logical, ptr); 829 ix = curp->p_idx + 1; 830 } else { 831 /* insert before */ 832 ext_debug("insert new index %d before: %llu\n", logical, ptr); 833 ix = curp->p_idx; 834 } 835 836 len = EXT_LAST_INDEX(curp->p_hdr) - ix + 1; 837 BUG_ON(len < 0); 838 if (len > 0) { 839 ext_debug("insert new index %d: " 840 "move %d indices from 0x%p to 0x%p\n", 841 logical, len, ix, ix + 1); 842 memmove(ix + 1, ix, len * sizeof(struct ext4_extent_idx)); 843 } 844 845 if (unlikely(ix > EXT_MAX_INDEX(curp->p_hdr))) { 846 EXT4_ERROR_INODE(inode, "ix > EXT_MAX_INDEX!"); 847 return -EIO; 848 } 849 850 ix->ei_block = cpu_to_le32(logical); 851 ext4_idx_store_pblock(ix, ptr); 852 le16_add_cpu(&curp->p_hdr->eh_entries, 1); 853 854 if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) { 855 EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!"); 856 return -EIO; 857 } 858 859 err = ext4_ext_dirty(handle, inode, curp); 860 ext4_std_error(inode->i_sb, err); 861 862 return err; 863} 864 865/* 866 * ext4_ext_split: 867 * inserts new subtree into the path, using free index entry 868 * at depth @at: 869 * - allocates all needed blocks (new leaf and all intermediate index blocks) 870 * - makes decision where to split 871 * - moves remaining extents and index entries (right to the split point) 872 * into the newly allocated blocks 873 * - initializes subtree 874 */ 875static int ext4_ext_split(handle_t *handle, struct inode *inode, 876 unsigned int flags, 877 struct ext4_ext_path *path, 878 struct ext4_extent *newext, int at) 879{ 880 struct buffer_head *bh = NULL; 881 int depth = ext_depth(inode); 882 struct ext4_extent_header *neh; 883 struct ext4_extent_idx *fidx; 884 int i = at, k, m, a; 885 ext4_fsblk_t newblock, oldblock; 886 __le32 border; 887 ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */ 888 int err = 0; 889 890 /* make decision: where to split? */ 891 /* FIXME: now decision is simplest: at current extent */ 892 893 /* if current leaf will be split, then we should use 894 * border from split point */ 895 if (unlikely(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr))) { 896 EXT4_ERROR_INODE(inode, "p_ext > EXT_MAX_EXTENT!"); 897 return -EIO; 898 } 899 if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) { 900 border = path[depth].p_ext[1].ee_block; 901 ext_debug("leaf will be split." 902 " next leaf starts at %d\n", 903 le32_to_cpu(border)); 904 } else { 905 border = newext->ee_block; 906 ext_debug("leaf will be added." 907 " next leaf starts at %d\n", 908 le32_to_cpu(border)); 909 } 910 911 /* 912 * If error occurs, then we break processing 913 * and mark filesystem read-only. index won't 914 * be inserted and tree will be in consistent 915 * state. Next mount will repair buffers too. 916 */ 917 918 /* 919 * Get array to track all allocated blocks. 920 * We need this to handle errors and free blocks 921 * upon them. 922 */ 923 ablocks = kzalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS); 924 if (!ablocks) 925 return -ENOMEM; 926 927 /* allocate all needed blocks */ 928 ext_debug("allocate %d blocks for indexes/leaf\n", depth - at); 929 for (a = 0; a < depth - at; a++) { 930 newblock = ext4_ext_new_meta_block(handle, inode, path, 931 newext, &err, flags); 932 if (newblock == 0) 933 goto cleanup; 934 ablocks[a] = newblock; 935 } 936 937 /* initialize new leaf */ 938 newblock = ablocks[--a]; 939 if (unlikely(newblock == 0)) { 940 EXT4_ERROR_INODE(inode, "newblock == 0!"); 941 err = -EIO; 942 goto cleanup; 943 } 944 bh = sb_getblk(inode->i_sb, newblock); 945 if (!bh) { 946 err = -EIO; 947 goto cleanup; 948 } 949 lock_buffer(bh); 950 951 err = ext4_journal_get_create_access(handle, bh); 952 if (err) 953 goto cleanup; 954 955 neh = ext_block_hdr(bh); 956 neh->eh_entries = 0; 957 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0)); 958 neh->eh_magic = EXT4_EXT_MAGIC; 959 neh->eh_depth = 0; 960 961 /* move remainder of path[depth] to the new leaf */ 962 if (unlikely(path[depth].p_hdr->eh_entries != 963 path[depth].p_hdr->eh_max)) { 964 EXT4_ERROR_INODE(inode, "eh_entries %d != eh_max %d!", 965 path[depth].p_hdr->eh_entries, 966 path[depth].p_hdr->eh_max); 967 err = -EIO; 968 goto cleanup; 969 } 970 /* start copy from next extent */ 971 m = EXT_MAX_EXTENT(path[depth].p_hdr) - path[depth].p_ext++; 972 ext4_ext_show_move(inode, path, newblock, depth); 973 if (m) { 974 struct ext4_extent *ex; 975 ex = EXT_FIRST_EXTENT(neh); 976 memmove(ex, path[depth].p_ext, sizeof(struct ext4_extent) * m); 977 le16_add_cpu(&neh->eh_entries, m); 978 } 979 980 ext4_extent_block_csum_set(inode, neh); 981 set_buffer_uptodate(bh); 982 unlock_buffer(bh); 983 984 err = ext4_handle_dirty_metadata(handle, inode, bh); 985 if (err) 986 goto cleanup; 987 brelse(bh); 988 bh = NULL; 989 990 /* correct old leaf */ 991 if (m) { 992 err = ext4_ext_get_access(handle, inode, path + depth); 993 if (err) 994 goto cleanup; 995 le16_add_cpu(&path[depth].p_hdr->eh_entries, -m); 996 err = ext4_ext_dirty(handle, inode, path + depth); 997 if (err) 998 goto cleanup; 999 1000 } 1001 1002 /* create intermediate indexes */ 1003 k = depth - at - 1; 1004 if (unlikely(k < 0)) { 1005 EXT4_ERROR_INODE(inode, "k %d < 0!", k); 1006 err = -EIO; 1007 goto cleanup; 1008 } 1009 if (k) 1010 ext_debug("create %d intermediate indices\n", k); 1011 /* insert new index into current index block */ 1012 /* current depth stored in i var */ 1013 i = depth - 1; 1014 while (k--) { 1015 oldblock = newblock; 1016 newblock = ablocks[--a]; 1017 bh = sb_getblk(inode->i_sb, newblock); 1018 if (!bh) { 1019 err = -EIO; 1020 goto cleanup; 1021 } 1022 lock_buffer(bh); 1023 1024 err = ext4_journal_get_create_access(handle, bh); 1025 if (err) 1026 goto cleanup; 1027 1028 neh = ext_block_hdr(bh); 1029 neh->eh_entries = cpu_to_le16(1); 1030 neh->eh_magic = EXT4_EXT_MAGIC; 1031 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0)); 1032 neh->eh_depth = cpu_to_le16(depth - i); 1033 fidx = EXT_FIRST_INDEX(neh); 1034 fidx->ei_block = border; 1035 ext4_idx_store_pblock(fidx, oldblock); 1036 1037 ext_debug("int.index at %d (block %llu): %u -> %llu\n", 1038 i, newblock, le32_to_cpu(border), oldblock); 1039 1040 /* move remainder of path[i] to the new index block */ 1041 if (unlikely(EXT_MAX_INDEX(path[i].p_hdr) != 1042 EXT_LAST_INDEX(path[i].p_hdr))) { 1043 EXT4_ERROR_INODE(inode, 1044 "EXT_MAX_INDEX != EXT_LAST_INDEX ee_block %d!", 1045 le32_to_cpu(path[i].p_ext->ee_block)); 1046 err = -EIO; 1047 goto cleanup; 1048 } 1049 /* start copy indexes */ 1050 m = EXT_MAX_INDEX(path[i].p_hdr) - path[i].p_idx++; 1051 ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx, 1052 EXT_MAX_INDEX(path[i].p_hdr)); 1053 ext4_ext_show_move(inode, path, newblock, i); 1054 if (m) { 1055 memmove(++fidx, path[i].p_idx, 1056 sizeof(struct ext4_extent_idx) * m); 1057 le16_add_cpu(&neh->eh_entries, m); 1058 } 1059 ext4_extent_block_csum_set(inode, neh); 1060 set_buffer_uptodate(bh); 1061 unlock_buffer(bh); 1062 1063 err = ext4_handle_dirty_metadata(handle, inode, bh); 1064 if (err) 1065 goto cleanup; 1066 brelse(bh); 1067 bh = NULL; 1068 1069 /* correct old index */ 1070 if (m) { 1071 err = ext4_ext_get_access(handle, inode, path + i); 1072 if (err) 1073 goto cleanup; 1074 le16_add_cpu(&path[i].p_hdr->eh_entries, -m); 1075 err = ext4_ext_dirty(handle, inode, path + i); 1076 if (err) 1077 goto cleanup; 1078 } 1079 1080 i--; 1081 } 1082 1083 /* insert new index */ 1084 err = ext4_ext_insert_index(handle, inode, path + at, 1085 le32_to_cpu(border), newblock); 1086 1087cleanup: 1088 if (bh) { 1089 if (buffer_locked(bh)) 1090 unlock_buffer(bh); 1091 brelse(bh); 1092 } 1093 1094 if (err) { 1095 /* free all allocated blocks in error case */ 1096 for (i = 0; i < depth; i++) { 1097 if (!ablocks[i]) 1098 continue; 1099 ext4_free_blocks(handle, inode, NULL, ablocks[i], 1, 1100 EXT4_FREE_BLOCKS_METADATA); 1101 } 1102 } 1103 kfree(ablocks); 1104 1105 return err; 1106} 1107 1108/* 1109 * ext4_ext_grow_indepth: 1110 * implements tree growing procedure: 1111 * - allocates new block 1112 * - moves top-level data (index block or leaf) into the new block 1113 * - initializes new top-level, creating index that points to the 1114 * just created block 1115 */ 1116static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode, 1117 unsigned int flags, 1118 struct ext4_extent *newext) 1119{ 1120 struct ext4_extent_header *neh; 1121 struct buffer_head *bh; 1122 ext4_fsblk_t newblock; 1123 int err = 0; 1124 1125 newblock = ext4_ext_new_meta_block(handle, inode, NULL, 1126 newext, &err, flags); 1127 if (newblock == 0) 1128 return err; 1129 1130 bh = sb_getblk(inode->i_sb, newblock); 1131 if (!bh) { 1132 err = -EIO; 1133 ext4_std_error(inode->i_sb, err); 1134 return err; 1135 } 1136 lock_buffer(bh); 1137 1138 err = ext4_journal_get_create_access(handle, bh); 1139 if (err) { 1140 unlock_buffer(bh); 1141 goto out; 1142 } 1143 1144 /* move top-level index/leaf into new block */ 1145 memmove(bh->b_data, EXT4_I(inode)->i_data, 1146 sizeof(EXT4_I(inode)->i_data)); 1147 1148 /* set size of new block */ 1149 neh = ext_block_hdr(bh); 1150 /* old root could have indexes or leaves 1151 * so calculate e_max right way */ 1152 if (ext_depth(inode)) 1153 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0)); 1154 else 1155 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0)); 1156 neh->eh_magic = EXT4_EXT_MAGIC; 1157 ext4_extent_block_csum_set(inode, neh); 1158 set_buffer_uptodate(bh); 1159 unlock_buffer(bh); 1160 1161 err = ext4_handle_dirty_metadata(handle, inode, bh); 1162 if (err) 1163 goto out; 1164 1165 /* Update top-level index: num,max,pointer */ 1166 neh = ext_inode_hdr(inode); 1167 neh->eh_entries = cpu_to_le16(1); 1168 ext4_idx_store_pblock(EXT_FIRST_INDEX(neh), newblock); 1169 if (neh->eh_depth == 0) { 1170 /* Root extent block becomes index block */ 1171 neh->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode, 0)); 1172 EXT_FIRST_INDEX(neh)->ei_block = 1173 EXT_FIRST_EXTENT(neh)->ee_block; 1174 } 1175 ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n", 1176 le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max), 1177 le32_to_cpu(EXT_FIRST_INDEX(neh)->ei_block), 1178 ext4_idx_pblock(EXT_FIRST_INDEX(neh))); 1179 1180 neh->eh_depth = cpu_to_le16(le16_to_cpu(neh->eh_depth) + 1); 1181 ext4_mark_inode_dirty(handle, inode); 1182out: 1183 brelse(bh); 1184 1185 return err; 1186} 1187 1188/* 1189 * ext4_ext_create_new_leaf: 1190 * finds empty index and adds new leaf. 1191 * if no free index is found, then it requests in-depth growing. 1192 */ 1193static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode, 1194 unsigned int flags, 1195 struct ext4_ext_path *path, 1196 struct ext4_extent *newext) 1197{ 1198 struct ext4_ext_path *curp; 1199 int depth, i, err = 0; 1200 1201repeat: 1202 i = depth = ext_depth(inode); 1203 1204 /* walk up to the tree and look for free index entry */ 1205 curp = path + depth; 1206 while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) { 1207 i--; 1208 curp--; 1209 } 1210 1211 /* we use already allocated block for index block, 1212 * so subsequent data blocks should be contiguous */ 1213 if (EXT_HAS_FREE_INDEX(curp)) { 1214 /* if we found index with free entry, then use that 1215 * entry: create all needed subtree and add new leaf */ 1216 err = ext4_ext_split(handle, inode, flags, path, newext, i); 1217 if (err) 1218 goto out; 1219 1220 /* refill path */ 1221 ext4_ext_drop_refs(path); 1222 path = ext4_ext_find_extent(inode, 1223 (ext4_lblk_t)le32_to_cpu(newext->ee_block), 1224 path); 1225 if (IS_ERR(path)) 1226 err = PTR_ERR(path); 1227 } else { 1228 /* tree is full, time to grow in depth */ 1229 err = ext4_ext_grow_indepth(handle, inode, flags, newext); 1230 if (err) 1231 goto out; 1232 1233 /* refill path */ 1234 ext4_ext_drop_refs(path); 1235 path = ext4_ext_find_extent(inode, 1236 (ext4_lblk_t)le32_to_cpu(newext->ee_block), 1237 path); 1238 if (IS_ERR(path)) { 1239 err = PTR_ERR(path); 1240 goto out; 1241 } 1242 1243 /* 1244 * only first (depth 0 -> 1) produces free space; 1245 * in all other cases we have to split the grown tree 1246 */ 1247 depth = ext_depth(inode); 1248 if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) { 1249 /* now we need to split */ 1250 goto repeat; 1251 } 1252 } 1253 1254out: 1255 return err; 1256} 1257 1258/* 1259 * search the closest allocated block to the left for *logical 1260 * and returns it at @logical + it's physical address at @phys 1261 * if *logical is the smallest allocated block, the function 1262 * returns 0 at @phys 1263 * return value contains 0 (success) or error code 1264 */ 1265static int ext4_ext_search_left(struct inode *inode, 1266 struct ext4_ext_path *path, 1267 ext4_lblk_t *logical, ext4_fsblk_t *phys) 1268{ 1269 struct ext4_extent_idx *ix; 1270 struct ext4_extent *ex; 1271 int depth, ee_len; 1272 1273 if (unlikely(path == NULL)) { 1274 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical); 1275 return -EIO; 1276 } 1277 depth = path->p_depth; 1278 *phys = 0; 1279 1280 if (depth == 0 && path->p_ext == NULL) 1281 return 0; 1282 1283 /* usually extent in the path covers blocks smaller 1284 * then *logical, but it can be that extent is the 1285 * first one in the file */ 1286 1287 ex = path[depth].p_ext; 1288 ee_len = ext4_ext_get_actual_len(ex); 1289 if (*logical < le32_to_cpu(ex->ee_block)) { 1290 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) { 1291 EXT4_ERROR_INODE(inode, 1292 "EXT_FIRST_EXTENT != ex *logical %d ee_block %d!", 1293 *logical, le32_to_cpu(ex->ee_block)); 1294 return -EIO; 1295 } 1296 while (--depth >= 0) { 1297 ix = path[depth].p_idx; 1298 if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) { 1299 EXT4_ERROR_INODE(inode, 1300 "ix (%d) != EXT_FIRST_INDEX (%d) (depth %d)!", 1301 ix != NULL ? le32_to_cpu(ix->ei_block) : 0, 1302 EXT_FIRST_INDEX(path[depth].p_hdr) != NULL ? 1303 le32_to_cpu(EXT_FIRST_INDEX(path[depth].p_hdr)->ei_block) : 0, 1304 depth); 1305 return -EIO; 1306 } 1307 } 1308 return 0; 1309 } 1310 1311 if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) { 1312 EXT4_ERROR_INODE(inode, 1313 "logical %d < ee_block %d + ee_len %d!", 1314 *logical, le32_to_cpu(ex->ee_block), ee_len); 1315 return -EIO; 1316 } 1317 1318 *logical = le32_to_cpu(ex->ee_block) + ee_len - 1; 1319 *phys = ext4_ext_pblock(ex) + ee_len - 1; 1320 return 0; 1321} 1322 1323/* 1324 * search the closest allocated block to the right for *logical 1325 * and returns it at @logical + it's physical address at @phys 1326 * if *logical is the largest allocated block, the function 1327 * returns 0 at @phys 1328 * return value contains 0 (success) or error code 1329 */ 1330static int ext4_ext_search_right(struct inode *inode, 1331 struct ext4_ext_path *path, 1332 ext4_lblk_t *logical, ext4_fsblk_t *phys, 1333 struct ext4_extent **ret_ex) 1334{ 1335 struct buffer_head *bh = NULL; 1336 struct ext4_extent_header *eh; 1337 struct ext4_extent_idx *ix; 1338 struct ext4_extent *ex; 1339 ext4_fsblk_t block; 1340 int depth; /* Note, NOT eh_depth; depth from top of tree */ 1341 int ee_len; 1342 1343 if (unlikely(path == NULL)) { 1344 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical); 1345 return -EIO; 1346 } 1347 depth = path->p_depth; 1348 *phys = 0; 1349 1350 if (depth == 0 && path->p_ext == NULL) 1351 return 0; 1352 1353 /* usually extent in the path covers blocks smaller 1354 * then *logical, but it can be that extent is the 1355 * first one in the file */ 1356 1357 ex = path[depth].p_ext; 1358 ee_len = ext4_ext_get_actual_len(ex); 1359 if (*logical < le32_to_cpu(ex->ee_block)) { 1360 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) { 1361 EXT4_ERROR_INODE(inode, 1362 "first_extent(path[%d].p_hdr) != ex", 1363 depth); 1364 return -EIO; 1365 } 1366 while (--depth >= 0) { 1367 ix = path[depth].p_idx; 1368 if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) { 1369 EXT4_ERROR_INODE(inode, 1370 "ix != EXT_FIRST_INDEX *logical %d!", 1371 *logical); 1372 return -EIO; 1373 } 1374 } 1375 goto found_extent; 1376 } 1377 1378 if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) { 1379 EXT4_ERROR_INODE(inode, 1380 "logical %d < ee_block %d + ee_len %d!", 1381 *logical, le32_to_cpu(ex->ee_block), ee_len); 1382 return -EIO; 1383 } 1384 1385 if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) { 1386 /* next allocated block in this leaf */ 1387 ex++; 1388 goto found_extent; 1389 } 1390 1391 /* go up and search for index to the right */ 1392 while (--depth >= 0) { 1393 ix = path[depth].p_idx; 1394 if (ix != EXT_LAST_INDEX(path[depth].p_hdr)) 1395 goto got_index; 1396 } 1397 1398 /* we've gone up to the root and found no index to the right */ 1399 return 0; 1400 1401got_index: 1402 /* we've found index to the right, let's 1403 * follow it and find the closest allocated 1404 * block to the right */ 1405 ix++; 1406 block = ext4_idx_pblock(ix); 1407 while (++depth < path->p_depth) { 1408 bh = sb_bread(inode->i_sb, block); 1409 if (bh == NULL) 1410 return -EIO; 1411 eh = ext_block_hdr(bh); 1412 /* subtract from p_depth to get proper eh_depth */ 1413 if (ext4_ext_check_block(inode, eh, 1414 path->p_depth - depth, bh)) { 1415 put_bh(bh); 1416 return -EIO; 1417 } 1418 ix = EXT_FIRST_INDEX(eh); 1419 block = ext4_idx_pblock(ix); 1420 put_bh(bh); 1421 } 1422 1423 bh = sb_bread(inode->i_sb, block); 1424 if (bh == NULL) 1425 return -EIO; 1426 eh = ext_block_hdr(bh); 1427 if (ext4_ext_check_block(inode, eh, path->p_depth - depth, bh)) { 1428 put_bh(bh); 1429 return -EIO; 1430 } 1431 ex = EXT_FIRST_EXTENT(eh); 1432found_extent: 1433 *logical = le32_to_cpu(ex->ee_block); 1434 *phys = ext4_ext_pblock(ex); 1435 *ret_ex = ex; 1436 if (bh) 1437 put_bh(bh); 1438 return 0; 1439} 1440 1441/* 1442 * ext4_ext_next_allocated_block: 1443 * returns allocated block in subsequent extent or EXT_MAX_BLOCKS. 1444 * NOTE: it considers block number from index entry as 1445 * allocated block. Thus, index entries have to be consistent 1446 * with leaves. 1447 */ 1448static ext4_lblk_t 1449ext4_ext_next_allocated_block(struct ext4_ext_path *path) 1450{ 1451 int depth; 1452 1453 BUG_ON(path == NULL); 1454 depth = path->p_depth; 1455 1456 if (depth == 0 && path->p_ext == NULL) 1457 return EXT_MAX_BLOCKS; 1458 1459 while (depth >= 0) { 1460 if (depth == path->p_depth) { 1461 /* leaf */ 1462 if (path[depth].p_ext && 1463 path[depth].p_ext != 1464 EXT_LAST_EXTENT(path[depth].p_hdr)) 1465 return le32_to_cpu(path[depth].p_ext[1].ee_block); 1466 } else { 1467 /* index */ 1468 if (path[depth].p_idx != 1469 EXT_LAST_INDEX(path[depth].p_hdr)) 1470 return le32_to_cpu(path[depth].p_idx[1].ei_block); 1471 } 1472 depth--; 1473 } 1474 1475 return EXT_MAX_BLOCKS; 1476} 1477 1478/* 1479 * ext4_ext_next_leaf_block: 1480 * returns first allocated block from next leaf or EXT_MAX_BLOCKS 1481 */ 1482static ext4_lblk_t ext4_ext_next_leaf_block(struct ext4_ext_path *path) 1483{ 1484 int depth; 1485 1486 BUG_ON(path == NULL); 1487 depth = path->p_depth; 1488 1489 /* zero-tree has no leaf blocks at all */ 1490 if (depth == 0) 1491 return EXT_MAX_BLOCKS; 1492 1493 /* go to index block */ 1494 depth--; 1495 1496 while (depth >= 0) { 1497 if (path[depth].p_idx != 1498 EXT_LAST_INDEX(path[depth].p_hdr)) 1499 return (ext4_lblk_t) 1500 le32_to_cpu(path[depth].p_idx[1].ei_block); 1501 depth--; 1502 } 1503 1504 return EXT_MAX_BLOCKS; 1505} 1506 1507/* 1508 * ext4_ext_correct_indexes: 1509 * if leaf gets modified and modified extent is first in the leaf, 1510 * then we have to correct all indexes above. 1511 * TODO: do we need to correct tree in all cases? 1512 */ 1513static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode, 1514 struct ext4_ext_path *path) 1515{ 1516 struct ext4_extent_header *eh; 1517 int depth = ext_depth(inode); 1518 struct ext4_extent *ex; 1519 __le32 border; 1520 int k, err = 0; 1521 1522 eh = path[depth].p_hdr; 1523 ex = path[depth].p_ext; 1524 1525 if (unlikely(ex == NULL || eh == NULL)) { 1526 EXT4_ERROR_INODE(inode, 1527 "ex %p == NULL or eh %p == NULL", ex, eh); 1528 return -EIO; 1529 } 1530 1531 if (depth == 0) { 1532 /* there is no tree at all */ 1533 return 0; 1534 } 1535 1536 if (ex != EXT_FIRST_EXTENT(eh)) { 1537 /* we correct tree if first leaf got modified only */ 1538 return 0; 1539 } 1540 1541 /* 1542 * TODO: we need correction if border is smaller than current one 1543 */ 1544 k = depth - 1; 1545 border = path[depth].p_ext->ee_block; 1546 err = ext4_ext_get_access(handle, inode, path + k); 1547 if (err) 1548 return err; 1549 path[k].p_idx->ei_block = border; 1550 err = ext4_ext_dirty(handle, inode, path + k); 1551 if (err) 1552 return err; 1553 1554 while (k--) { 1555 /* change all left-side indexes */ 1556 if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr)) 1557 break; 1558 err = ext4_ext_get_access(handle, inode, path + k); 1559 if (err) 1560 break; 1561 path[k].p_idx->ei_block = border; 1562 err = ext4_ext_dirty(handle, inode, path + k); 1563 if (err) 1564 break; 1565 } 1566 1567 return err; 1568} 1569 1570int 1571ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1, 1572 struct ext4_extent *ex2) 1573{ 1574 unsigned short ext1_ee_len, ext2_ee_len, max_len; 1575 1576 /* 1577 * Make sure that either both extents are uninitialized, or 1578 * both are _not_. 1579 */ 1580 if (ext4_ext_is_uninitialized(ex1) ^ ext4_ext_is_uninitialized(ex2)) 1581 return 0; 1582 1583 if (ext4_ext_is_uninitialized(ex1)) 1584 max_len = EXT_UNINIT_MAX_LEN; 1585 else 1586 max_len = EXT_INIT_MAX_LEN; 1587 1588 ext1_ee_len = ext4_ext_get_actual_len(ex1); 1589 ext2_ee_len = ext4_ext_get_actual_len(ex2); 1590 1591 if (le32_to_cpu(ex1->ee_block) + ext1_ee_len != 1592 le32_to_cpu(ex2->ee_block)) 1593 return 0; 1594 1595 /* 1596 * To allow future support for preallocated extents to be added 1597 * as an RO_COMPAT feature, refuse to merge to extents if 1598 * this can result in the top bit of ee_len being set. 1599 */ 1600 if (ext1_ee_len + ext2_ee_len > max_len) 1601 return 0; 1602#ifdef AGGRESSIVE_TEST 1603 if (ext1_ee_len >= 4) 1604 return 0; 1605#endif 1606 1607 if (ext4_ext_pblock(ex1) + ext1_ee_len == ext4_ext_pblock(ex2)) 1608 return 1; 1609 return 0; 1610} 1611 1612/* 1613 * This function tries to merge the "ex" extent to the next extent in the tree. 1614 * It always tries to merge towards right. If you want to merge towards 1615 * left, pass "ex - 1" as argument instead of "ex". 1616 * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns 1617 * 1 if they got merged. 1618 */ 1619static int ext4_ext_try_to_merge_right(struct inode *inode, 1620 struct ext4_ext_path *path, 1621 struct ext4_extent *ex) 1622{ 1623 struct ext4_extent_header *eh; 1624 unsigned int depth, len; 1625 int merge_done = 0; 1626 int uninitialized = 0; 1627 1628 depth = ext_depth(inode); 1629 BUG_ON(path[depth].p_hdr == NULL); 1630 eh = path[depth].p_hdr; 1631 1632 while (ex < EXT_LAST_EXTENT(eh)) { 1633 if (!ext4_can_extents_be_merged(inode, ex, ex + 1)) 1634 break; 1635 /* merge with next extent! */ 1636 if (ext4_ext_is_uninitialized(ex)) 1637 uninitialized = 1; 1638 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex) 1639 + ext4_ext_get_actual_len(ex + 1)); 1640 if (uninitialized) 1641 ext4_ext_mark_uninitialized(ex); 1642 1643 if (ex + 1 < EXT_LAST_EXTENT(eh)) { 1644 len = (EXT_LAST_EXTENT(eh) - ex - 1) 1645 * sizeof(struct ext4_extent); 1646 memmove(ex + 1, ex + 2, len); 1647 } 1648 le16_add_cpu(&eh->eh_entries, -1); 1649 merge_done = 1; 1650 WARN_ON(eh->eh_entries == 0); 1651 if (!eh->eh_entries) 1652 EXT4_ERROR_INODE(inode, "eh->eh_entries = 0!"); 1653 } 1654 1655 return merge_done; 1656} 1657 1658/* 1659 * This function does a very simple check to see if we can collapse 1660 * an extent tree with a single extent tree leaf block into the inode. 1661 */ 1662static void ext4_ext_try_to_merge_up(handle_t *handle, 1663 struct inode *inode, 1664 struct ext4_ext_path *path) 1665{ 1666 size_t s; 1667 unsigned max_root = ext4_ext_space_root(inode, 0); 1668 ext4_fsblk_t blk; 1669 1670 if ((path[0].p_depth != 1) || 1671 (le16_to_cpu(path[0].p_hdr->eh_entries) != 1) || 1672 (le16_to_cpu(path[1].p_hdr->eh_entries) > max_root)) 1673 return; 1674 1675 /* 1676 * We need to modify the block allocation bitmap and the block 1677 * group descriptor to release the extent tree block. If we 1678 * can't get the journal credits, give up. 1679 */ 1680 if (ext4_journal_extend(handle, 2)) 1681 return; 1682 1683 /* 1684 * Copy the extent data up to the inode 1685 */ 1686 blk = ext4_idx_pblock(path[0].p_idx); 1687 s = le16_to_cpu(path[1].p_hdr->eh_entries) * 1688 sizeof(struct ext4_extent_idx); 1689 s += sizeof(struct ext4_extent_header); 1690 1691 memcpy(path[0].p_hdr, path[1].p_hdr, s); 1692 path[0].p_depth = 0; 1693 path[0].p_ext = EXT_FIRST_EXTENT(path[0].p_hdr) + 1694 (path[1].p_ext - EXT_FIRST_EXTENT(path[1].p_hdr)); 1695 path[0].p_hdr->eh_max = cpu_to_le16(max_root); 1696 1697 brelse(path[1].p_bh); 1698 ext4_free_blocks(handle, inode, NULL, blk, 1, 1699 EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET); 1700} 1701 1702/* 1703 * This function tries to merge the @ex extent to neighbours in the tree. 1704 * return 1 if merge left else 0. 1705 */ 1706static void ext4_ext_try_to_merge(handle_t *handle, 1707 struct inode *inode, 1708 struct ext4_ext_path *path, 1709 struct ext4_extent *ex) { 1710 struct ext4_extent_header *eh; 1711 unsigned int depth; 1712 int merge_done = 0; 1713 1714 depth = ext_depth(inode); 1715 BUG_ON(path[depth].p_hdr == NULL); 1716 eh = path[depth].p_hdr; 1717 1718 if (ex > EXT_FIRST_EXTENT(eh)) 1719 merge_done = ext4_ext_try_to_merge_right(inode, path, ex - 1); 1720 1721 if (!merge_done) 1722 (void) ext4_ext_try_to_merge_right(inode, path, ex); 1723 1724 ext4_ext_try_to_merge_up(handle, inode, path); 1725} 1726 1727/* 1728 * check if a portion of the "newext" extent overlaps with an 1729 * existing extent. 1730 * 1731 * If there is an overlap discovered, it updates the length of the newext 1732 * such that there will be no overlap, and then returns 1. 1733 * If there is no overlap found, it returns 0. 1734 */ 1735static unsigned int ext4_ext_check_overlap(struct ext4_sb_info *sbi, 1736 struct inode *inode, 1737 struct ext4_extent *newext, 1738 struct ext4_ext_path *path) 1739{ 1740 ext4_lblk_t b1, b2; 1741 unsigned int depth, len1; 1742 unsigned int ret = 0; 1743 1744 b1 = le32_to_cpu(newext->ee_block); 1745 len1 = ext4_ext_get_actual_len(newext); 1746 depth = ext_depth(inode); 1747 if (!path[depth].p_ext) 1748 goto out; 1749 b2 = le32_to_cpu(path[depth].p_ext->ee_block); 1750 b2 &= ~(sbi->s_cluster_ratio - 1); 1751 1752 /* 1753 * get the next allocated block if the extent in the path 1754 * is before the requested block(s) 1755 */ 1756 if (b2 < b1) { 1757 b2 = ext4_ext_next_allocated_block(path); 1758 if (b2 == EXT_MAX_BLOCKS) 1759 goto out; 1760 b2 &= ~(sbi->s_cluster_ratio - 1); 1761 } 1762 1763 /* check for wrap through zero on extent logical start block*/ 1764 if (b1 + len1 < b1) { 1765 len1 = EXT_MAX_BLOCKS - b1; 1766 newext->ee_len = cpu_to_le16(len1); 1767 ret = 1; 1768 } 1769 1770 /* check for overlap */ 1771 if (b1 + len1 > b2) { 1772 newext->ee_len = cpu_to_le16(b2 - b1); 1773 ret = 1; 1774 } 1775out: 1776 return ret; 1777} 1778 1779/* 1780 * ext4_ext_insert_extent: 1781 * tries to merge requsted extent into the existing extent or 1782 * inserts requested extent as new one into the tree, 1783 * creating new leaf in the no-space case. 1784 */ 1785int ext4_ext_insert_extent(handle_t *handle, struct inode *inode, 1786 struct ext4_ext_path *path, 1787 struct ext4_extent *newext, int flag) 1788{ 1789 struct ext4_extent_header *eh; 1790 struct ext4_extent *ex, *fex; 1791 struct ext4_extent *nearex; /* nearest extent */ 1792 struct ext4_ext_path *npath = NULL; 1793 int depth, len, err; 1794 ext4_lblk_t next; 1795 unsigned uninitialized = 0; 1796 int flags = 0; 1797 1798 if (unlikely(ext4_ext_get_actual_len(newext) == 0)) { 1799 EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0"); 1800 return -EIO; 1801 } 1802 depth = ext_depth(inode); 1803 ex = path[depth].p_ext; 1804 if (unlikely(path[depth].p_hdr == NULL)) { 1805 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth); 1806 return -EIO; 1807 } 1808 1809 /* try to insert block into found extent and return */ 1810 if (ex && !(flag & EXT4_GET_BLOCKS_PRE_IO) 1811 && ext4_can_extents_be_merged(inode, ex, newext)) { 1812 ext_debug("append [%d]%d block to %u:[%d]%d (from %llu)\n", 1813 ext4_ext_is_uninitialized(newext), 1814 ext4_ext_get_actual_len(newext), 1815 le32_to_cpu(ex->ee_block), 1816 ext4_ext_is_uninitialized(ex), 1817 ext4_ext_get_actual_len(ex), 1818 ext4_ext_pblock(ex)); 1819 err = ext4_ext_get_access(handle, inode, path + depth); 1820 if (err) 1821 return err; 1822 1823 /* 1824 * ext4_can_extents_be_merged should have checked that either 1825 * both extents are uninitialized, or both aren't. Thus we 1826 * need to check only one of them here. 1827 */ 1828 if (ext4_ext_is_uninitialized(ex)) 1829 uninitialized = 1; 1830 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex) 1831 + ext4_ext_get_actual_len(newext)); 1832 if (uninitialized) 1833 ext4_ext_mark_uninitialized(ex); 1834 eh = path[depth].p_hdr; 1835 nearex = ex; 1836 goto merge; 1837 } 1838 1839 depth = ext_depth(inode); 1840 eh = path[depth].p_hdr; 1841 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) 1842 goto has_space; 1843 1844 /* probably next leaf has space for us? */ 1845 fex = EXT_LAST_EXTENT(eh); 1846 next = EXT_MAX_BLOCKS; 1847 if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block)) 1848 next = ext4_ext_next_leaf_block(path); 1849 if (next != EXT_MAX_BLOCKS) { 1850 ext_debug("next leaf block - %u\n", next); 1851 BUG_ON(npath != NULL); 1852 npath = ext4_ext_find_extent(inode, next, NULL); 1853 if (IS_ERR(npath)) 1854 return PTR_ERR(npath); 1855 BUG_ON(npath->p_depth != path->p_depth); 1856 eh = npath[depth].p_hdr; 1857 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) { 1858 ext_debug("next leaf isn't full(%d)\n", 1859 le16_to_cpu(eh->eh_entries)); 1860 path = npath; 1861 goto has_space; 1862 } 1863 ext_debug("next leaf has no free space(%d,%d)\n", 1864 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max)); 1865 } 1866 1867 /* 1868 * There is no free space in the found leaf. 1869 * We're gonna add a new leaf in the tree. 1870 */ 1871 if (flag & EXT4_GET_BLOCKS_PUNCH_OUT_EXT) 1872 flags = EXT4_MB_USE_ROOT_BLOCKS; 1873 err = ext4_ext_create_new_leaf(handle, inode, flags, path, newext); 1874 if (err) 1875 goto cleanup; 1876 depth = ext_depth(inode); 1877 eh = path[depth].p_hdr; 1878 1879has_space: 1880 nearex = path[depth].p_ext; 1881 1882 err = ext4_ext_get_access(handle, inode, path + depth); 1883 if (err) 1884 goto cleanup; 1885 1886 if (!nearex) { 1887 /* there is no extent in this leaf, create first one */ 1888 ext_debug("first extent in the leaf: %u:%llu:[%d]%d\n", 1889 le32_to_cpu(newext->ee_block), 1890 ext4_ext_pblock(newext), 1891 ext4_ext_is_uninitialized(newext), 1892 ext4_ext_get_actual_len(newext)); 1893 nearex = EXT_FIRST_EXTENT(eh); 1894 } else { 1895 if (le32_to_cpu(newext->ee_block) 1896 > le32_to_cpu(nearex->ee_block)) { 1897 /* Insert after */ 1898 ext_debug("insert %u:%llu:[%d]%d before: " 1899 "nearest %p\n", 1900 le32_to_cpu(newext->ee_block), 1901 ext4_ext_pblock(newext), 1902 ext4_ext_is_uninitialized(newext), 1903 ext4_ext_get_actual_len(newext), 1904 nearex); 1905 nearex++; 1906 } else { 1907 /* Insert before */ 1908 BUG_ON(newext->ee_block == nearex->ee_block); 1909 ext_debug("insert %u:%llu:[%d]%d after: " 1910 "nearest %p\n", 1911 le32_to_cpu(newext->ee_block), 1912 ext4_ext_pblock(newext), 1913 ext4_ext_is_uninitialized(newext), 1914 ext4_ext_get_actual_len(newext), 1915 nearex); 1916 } 1917 len = EXT_LAST_EXTENT(eh) - nearex + 1; 1918 if (len > 0) { 1919 ext_debug("insert %u:%llu:[%d]%d: " 1920 "move %d extents from 0x%p to 0x%p\n", 1921 le32_to_cpu(newext->ee_block), 1922 ext4_ext_pblock(newext), 1923 ext4_ext_is_uninitialized(newext), 1924 ext4_ext_get_actual_len(newext), 1925 len, nearex, nearex + 1); 1926 memmove(nearex + 1, nearex, 1927 len * sizeof(struct ext4_extent)); 1928 } 1929 } 1930 1931 le16_add_cpu(&eh->eh_entries, 1); 1932 path[depth].p_ext = nearex; 1933 nearex->ee_block = newext->ee_block; 1934 ext4_ext_store_pblock(nearex, ext4_ext_pblock(newext)); 1935 nearex->ee_len = newext->ee_len; 1936 1937merge: 1938 /* try to merge extents */ 1939 if (!(flag & EXT4_GET_BLOCKS_PRE_IO)) 1940 ext4_ext_try_to_merge(handle, inode, path, nearex); 1941 1942 1943 /* time to correct all indexes above */ 1944 err = ext4_ext_correct_indexes(handle, inode, path); 1945 if (err) 1946 goto cleanup; 1947 1948 err = ext4_ext_dirty(handle, inode, path + path->p_depth); 1949 1950cleanup: 1951 if (npath) { 1952 ext4_ext_drop_refs(npath); 1953 kfree(npath); 1954 } 1955 ext4_ext_invalidate_cache(inode); 1956 return err; 1957} 1958 1959static int ext4_ext_walk_space(struct inode *inode, ext4_lblk_t block, 1960 ext4_lblk_t num, ext_prepare_callback func, 1961 void *cbdata) 1962{ 1963 struct ext4_ext_path *path = NULL; 1964 struct ext4_ext_cache cbex; 1965 struct ext4_extent *ex; 1966 ext4_lblk_t next, start = 0, end = 0; 1967 ext4_lblk_t last = block + num; 1968 int depth, exists, err = 0; 1969 1970 BUG_ON(func == NULL); 1971 BUG_ON(inode == NULL); 1972 1973 while (block < last && block != EXT_MAX_BLOCKS) { 1974 num = last - block; 1975 /* find extent for this block */ 1976 down_read(&EXT4_I(inode)->i_data_sem); 1977 path = ext4_ext_find_extent(inode, block, path); 1978 up_read(&EXT4_I(inode)->i_data_sem); 1979 if (IS_ERR(path)) { 1980 err = PTR_ERR(path); 1981 path = NULL; 1982 break; 1983 } 1984 1985 depth = ext_depth(inode); 1986 if (unlikely(path[depth].p_hdr == NULL)) { 1987 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth); 1988 err = -EIO; 1989 break; 1990 } 1991 ex = path[depth].p_ext; 1992 next = ext4_ext_next_allocated_block(path); 1993 1994 exists = 0; 1995 if (!ex) { 1996 /* there is no extent yet, so try to allocate 1997 * all requested space */ 1998 start = block; 1999 end = block + num; 2000 } else if (le32_to_cpu(ex->ee_block) > block) { 2001 /* need to allocate space before found extent */ 2002 start = block; 2003 end = le32_to_cpu(ex->ee_block); 2004 if (block + num < end) 2005 end = block + num; 2006 } else if (block >= le32_to_cpu(ex->ee_block) 2007 + ext4_ext_get_actual_len(ex)) { 2008 /* need to allocate space after found extent */ 2009 start = block; 2010 end = block + num; 2011 if (end >= next) 2012 end = next; 2013 } else if (block >= le32_to_cpu(ex->ee_block)) { 2014 /* 2015 * some part of requested space is covered 2016 * by found extent 2017 */ 2018 start = block; 2019 end = le32_to_cpu(ex->ee_block) 2020 + ext4_ext_get_actual_len(ex); 2021 if (block + num < end) 2022 end = block + num; 2023 exists = 1; 2024 } else { 2025 BUG(); 2026 } 2027 BUG_ON(end <= start); 2028 2029 if (!exists) { 2030 cbex.ec_block = start; 2031 cbex.ec_len = end - start; 2032 cbex.ec_start = 0; 2033 } else { 2034 cbex.ec_block = le32_to_cpu(ex->ee_block); 2035 cbex.ec_len = ext4_ext_get_actual_len(ex); 2036 cbex.ec_start = ext4_ext_pblock(ex); 2037 } 2038 2039 if (unlikely(cbex.ec_len == 0)) { 2040 EXT4_ERROR_INODE(inode, "cbex.ec_len == 0"); 2041 err = -EIO; 2042 break; 2043 } 2044 err = func(inode, next, &cbex, ex, cbdata); 2045 ext4_ext_drop_refs(path); 2046 2047 if (err < 0) 2048 break; 2049 2050 if (err == EXT_REPEAT) 2051 continue; 2052 else if (err == EXT_BREAK) { 2053 err = 0; 2054 break; 2055 } 2056 2057 if (ext_depth(inode) != depth) { 2058 /* depth was changed. we have to realloc path */ 2059 kfree(path); 2060 path = NULL; 2061 } 2062 2063 block = cbex.ec_block + cbex.ec_len; 2064 } 2065 2066 if (path) { 2067 ext4_ext_drop_refs(path); 2068 kfree(path); 2069 } 2070 2071 return err; 2072} 2073 2074static void 2075ext4_ext_put_in_cache(struct inode *inode, ext4_lblk_t block, 2076 __u32 len, ext4_fsblk_t start) 2077{ 2078 struct ext4_ext_cache *cex; 2079 BUG_ON(len == 0); 2080 spin_lock(&EXT4_I(inode)->i_block_reservation_lock); 2081 trace_ext4_ext_put_in_cache(inode, block, len, start); 2082 cex = &EXT4_I(inode)->i_cached_extent; 2083 cex->ec_block = block; 2084 cex->ec_len = len; 2085 cex->ec_start = start; 2086 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock); 2087} 2088 2089/* 2090 * ext4_ext_put_gap_in_cache: 2091 * calculate boundaries of the gap that the requested block fits into 2092 * and cache this gap 2093 */ 2094static void 2095ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path, 2096 ext4_lblk_t block) 2097{ 2098 int depth = ext_depth(inode); 2099 unsigned long len; 2100 ext4_lblk_t lblock; 2101 struct ext4_extent *ex; 2102 2103 ex = path[depth].p_ext; 2104 if (ex == NULL) { 2105 /* there is no extent yet, so gap is [0;-] */ 2106 lblock = 0; 2107 len = EXT_MAX_BLOCKS; 2108 ext_debug("cache gap(whole file):"); 2109 } else if (block < le32_to_cpu(ex->ee_block)) { 2110 lblock = block; 2111 len = le32_to_cpu(ex->ee_block) - block; 2112 ext_debug("cache gap(before): %u [%u:%u]", 2113 block, 2114 le32_to_cpu(ex->ee_block), 2115 ext4_ext_get_actual_len(ex)); 2116 } else if (block >= le32_to_cpu(ex->ee_block) 2117 + ext4_ext_get_actual_len(ex)) { 2118 ext4_lblk_t next; 2119 lblock = le32_to_cpu(ex->ee_block) 2120 + ext4_ext_get_actual_len(ex); 2121 2122 next = ext4_ext_next_allocated_block(path); 2123 ext_debug("cache gap(after): [%u:%u] %u", 2124 le32_to_cpu(ex->ee_block), 2125 ext4_ext_get_actual_len(ex), 2126 block); 2127 BUG_ON(next == lblock); 2128 len = next - lblock; 2129 } else { 2130 lblock = len = 0; 2131 BUG(); 2132 } 2133 2134 ext_debug(" -> %u:%lu\n", lblock, len); 2135 ext4_ext_put_in_cache(inode, lblock, len, 0); 2136} 2137 2138/* 2139 * ext4_ext_check_cache() 2140 * Checks to see if the given block is in the cache. 2141 * If it is, the cached extent is stored in the given 2142 * cache extent pointer. If the cached extent is a hole, 2143 * this routine should be used instead of 2144 * ext4_ext_in_cache if the calling function needs to 2145 * know the size of the hole. 2146 * 2147 * @inode: The files inode 2148 * @block: The block to look for in the cache 2149 * @ex: Pointer where the cached extent will be stored 2150 * if it contains block 2151 * 2152 * Return 0 if cache is invalid; 1 if the cache is valid 2153 */ 2154static int ext4_ext_check_cache(struct inode *inode, ext4_lblk_t block, 2155 struct ext4_ext_cache *ex){ 2156 struct ext4_ext_cache *cex; 2157 struct ext4_sb_info *sbi; 2158 int ret = 0; 2159 2160 /* 2161 * We borrow i_block_reservation_lock to protect i_cached_extent 2162 */ 2163 spin_lock(&EXT4_I(inode)->i_block_reservation_lock); 2164 cex = &EXT4_I(inode)->i_cached_extent; 2165 sbi = EXT4_SB(inode->i_sb); 2166 2167 /* has cache valid data? */ 2168 if (cex->ec_len == 0) 2169 goto errout; 2170 2171 if (in_range(block, cex->ec_block, cex->ec_len)) { 2172 memcpy(ex, cex, sizeof(struct ext4_ext_cache)); 2173 ext_debug("%u cached by %u:%u:%llu\n", 2174 block, 2175 cex->ec_block, cex->ec_len, cex->ec_start); 2176 ret = 1; 2177 } 2178errout: 2179 trace_ext4_ext_in_cache(inode, block, ret); 2180 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock); 2181 return ret; 2182} 2183 2184/* 2185 * ext4_ext_in_cache() 2186 * Checks to see if the given block is in the cache. 2187 * If it is, the cached extent is stored in the given 2188 * extent pointer. 2189 * 2190 * @inode: The files inode 2191 * @block: The block to look for in the cache 2192 * @ex: Pointer where the cached extent will be stored 2193 * if it contains block 2194 * 2195 * Return 0 if cache is invalid; 1 if the cache is valid 2196 */ 2197static int 2198ext4_ext_in_cache(struct inode *inode, ext4_lblk_t block, 2199 struct ext4_extent *ex) 2200{ 2201 struct ext4_ext_cache cex; 2202 int ret = 0; 2203 2204 if (ext4_ext_check_cache(inode, block, &cex)) { 2205 ex->ee_block = cpu_to_le32(cex.ec_block); 2206 ext4_ext_store_pblock(ex, cex.ec_start); 2207 ex->ee_len = cpu_to_le16(cex.ec_len); 2208 ret = 1; 2209 } 2210 2211 return ret; 2212} 2213 2214 2215/* 2216 * ext4_ext_rm_idx: 2217 * removes index from the index block. 2218 */ 2219static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode, 2220 struct ext4_ext_path *path) 2221{ 2222 int err; 2223 ext4_fsblk_t leaf; 2224 2225 /* free index block */ 2226 path--; 2227 leaf = ext4_idx_pblock(path->p_idx); 2228 if (unlikely(path->p_hdr->eh_entries == 0)) { 2229 EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0"); 2230 return -EIO; 2231 } 2232 err = ext4_ext_get_access(handle, inode, path); 2233 if (err) 2234 return err; 2235 2236 if (path->p_idx != EXT_LAST_INDEX(path->p_hdr)) { 2237 int len = EXT_LAST_INDEX(path->p_hdr) - path->p_idx; 2238 len *= sizeof(struct ext4_extent_idx); 2239 memmove(path->p_idx, path->p_idx + 1, len); 2240 } 2241 2242 le16_add_cpu(&path->p_hdr->eh_entries, -1); 2243 err = ext4_ext_dirty(handle, inode, path); 2244 if (err) 2245 return err; 2246 ext_debug("index is empty, remove it, free block %llu\n", leaf); 2247 trace_ext4_ext_rm_idx(inode, leaf); 2248 2249 ext4_free_blocks(handle, inode, NULL, leaf, 1, 2250 EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET); 2251 return err; 2252} 2253 2254/* 2255 * ext4_ext_calc_credits_for_single_extent: 2256 * This routine returns max. credits that needed to insert an extent 2257 * to the extent tree. 2258 * When pass the actual path, the caller should calculate credits 2259 * under i_data_sem. 2260 */ 2261int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks, 2262 struct ext4_ext_path *path) 2263{ 2264 if (path) { 2265 int depth = ext_depth(inode); 2266 int ret = 0; 2267 2268 /* probably there is space in leaf? */ 2269 if (le16_to_cpu(path[depth].p_hdr->eh_entries) 2270 < le16_to_cpu(path[depth].p_hdr->eh_max)) { 2271 2272 /* 2273 * There are some space in the leaf tree, no 2274 * need to account for leaf block credit 2275 * 2276 * bitmaps and block group descriptor blocks 2277 * and other metadata blocks still need to be 2278 * accounted. 2279 */ 2280 /* 1 bitmap, 1 block group descriptor */ 2281 ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb); 2282 return ret; 2283 } 2284 } 2285 2286 return ext4_chunk_trans_blocks(inode, nrblocks); 2287} 2288 2289/* 2290 * How many index/leaf blocks need to change/allocate to modify nrblocks? 2291 * 2292 * if nrblocks are fit in a single extent (chunk flag is 1), then 2293 * in the worse case, each tree level index/leaf need to be changed 2294 * if the tree split due to insert a new extent, then the old tree 2295 * index/leaf need to be updated too 2296 * 2297 * If the nrblocks are discontiguous, they could cause 2298 * the whole tree split more than once, but this is really rare. 2299 */ 2300int ext4_ext_index_trans_blocks(struct inode *inode, int nrblocks, int chunk) 2301{ 2302 int index; 2303 int depth = ext_depth(inode); 2304 2305 if (chunk) 2306 index = depth * 2; 2307 else 2308 index = depth * 3; 2309 2310 return index; 2311} 2312 2313static int ext4_remove_blocks(handle_t *handle, struct inode *inode, 2314 struct ext4_extent *ex, 2315 ext4_fsblk_t *partial_cluster, 2316 ext4_lblk_t from, ext4_lblk_t to) 2317{ 2318 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 2319 unsigned short ee_len = ext4_ext_get_actual_len(ex); 2320 ext4_fsblk_t pblk; 2321 int flags = EXT4_FREE_BLOCKS_FORGET; 2322 2323 if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) 2324 flags |= EXT4_FREE_BLOCKS_METADATA; 2325 /* 2326 * For bigalloc file systems, we never free a partial cluster 2327 * at the beginning of the extent. Instead, we make a note 2328 * that we tried freeing the cluster, and check to see if we 2329 * need to free it on a subsequent call to ext4_remove_blocks, 2330 * or at the end of the ext4_truncate() operation. 2331 */ 2332 flags |= EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER; 2333 2334 trace_ext4_remove_blocks(inode, ex, from, to, *partial_cluster); 2335 /* 2336 * If we have a partial cluster, and it's different from the 2337 * cluster of the last block, we need to explicitly free the 2338 * partial cluster here. 2339 */ 2340 pblk = ext4_ext_pblock(ex) + ee_len - 1; 2341 if (*partial_cluster && (EXT4_B2C(sbi, pblk) != *partial_cluster)) { 2342 ext4_free_blocks(handle, inode, NULL, 2343 EXT4_C2B(sbi, *partial_cluster), 2344 sbi->s_cluster_ratio, flags); 2345 *partial_cluster = 0; 2346 } 2347 2348#ifdef EXTENTS_STATS 2349 { 2350 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 2351 spin_lock(&sbi->s_ext_stats_lock); 2352 sbi->s_ext_blocks += ee_len; 2353 sbi->s_ext_extents++; 2354 if (ee_len < sbi->s_ext_min) 2355 sbi->s_ext_min = ee_len; 2356 if (ee_len > sbi->s_ext_max) 2357 sbi->s_ext_max = ee_len; 2358 if (ext_depth(inode) > sbi->s_depth_max) 2359 sbi->s_depth_max = ext_depth(inode); 2360 spin_unlock(&sbi->s_ext_stats_lock); 2361 } 2362#endif 2363 if (from >= le32_to_cpu(ex->ee_block) 2364 && to == le32_to_cpu(ex->ee_block) + ee_len - 1) { 2365 /* tail removal */ 2366 ext4_lblk_t num; 2367 2368 num = le32_to_cpu(ex->ee_block) + ee_len - from; 2369 pblk = ext4_ext_pblock(ex) + ee_len - num; 2370 ext_debug("free last %u blocks starting %llu\n", num, pblk); 2371 ext4_free_blocks(handle, inode, NULL, pblk, num, flags); 2372 /* 2373 * If the block range to be freed didn't start at the 2374 * beginning of a cluster, and we removed the entire 2375 * extent, save the partial cluster here, since we 2376 * might need to delete if we determine that the 2377 * truncate operation has removed all of the blocks in 2378 * the cluster. 2379 */ 2380 if (pblk & (sbi->s_cluster_ratio - 1) && 2381 (ee_len == num)) 2382 *partial_cluster = EXT4_B2C(sbi, pblk); 2383 else 2384 *partial_cluster = 0; 2385 } else if (from == le32_to_cpu(ex->ee_block) 2386 && to <= le32_to_cpu(ex->ee_block) + ee_len - 1) { 2387 /* head removal */ 2388 ext4_lblk_t num; 2389 ext4_fsblk_t start; 2390 2391 num = to - from; 2392 start = ext4_ext_pblock(ex); 2393 2394 ext_debug("free first %u blocks starting %llu\n", num, start); 2395 ext4_free_blocks(handle, inode, NULL, start, num, flags); 2396 2397 } else { 2398 printk(KERN_INFO "strange request: removal(2) " 2399 "%u-%u from %u:%u\n", 2400 from, to, le32_to_cpu(ex->ee_block), ee_len); 2401 } 2402 return 0; 2403} 2404 2405 2406/* 2407 * ext4_ext_rm_leaf() Removes the extents associated with the 2408 * blocks appearing between "start" and "end", and splits the extents 2409 * if "start" and "end" appear in the same extent 2410 * 2411 * @handle: The journal handle 2412 * @inode: The files inode 2413 * @path: The path to the leaf 2414 * @start: The first block to remove 2415 * @end: The last block to remove 2416 */ 2417static int 2418ext4_ext_rm_leaf(handle_t *handle, struct inode *inode, 2419 struct ext4_ext_path *path, ext4_fsblk_t *partial_cluster, 2420 ext4_lblk_t start, ext4_lblk_t end) 2421{ 2422 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 2423 int err = 0, correct_index = 0; 2424 int depth = ext_depth(inode), credits; 2425 struct ext4_extent_header *eh; 2426 ext4_lblk_t a, b; 2427 unsigned num; 2428 ext4_lblk_t ex_ee_block; 2429 unsigned short ex_ee_len; 2430 unsigned uninitialized = 0; 2431 struct ext4_extent *ex; 2432 2433 /* the header must be checked already in ext4_ext_remove_space() */ 2434 ext_debug("truncate since %u in leaf to %u\n", start, end); 2435 if (!path[depth].p_hdr) 2436 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh); 2437 eh = path[depth].p_hdr; 2438 if (unlikely(path[depth].p_hdr == NULL)) { 2439 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth); 2440 return -EIO; 2441 } 2442 /* find where to start removing */ 2443 ex = EXT_LAST_EXTENT(eh); 2444 2445 ex_ee_block = le32_to_cpu(ex->ee_block); 2446 ex_ee_len = ext4_ext_get_actual_len(ex); 2447 2448 trace_ext4_ext_rm_leaf(inode, start, ex, *partial_cluster); 2449 2450 while (ex >= EXT_FIRST_EXTENT(eh) && 2451 ex_ee_block + ex_ee_len > start) { 2452 2453 if (ext4_ext_is_uninitialized(ex)) 2454 uninitialized = 1; 2455 else 2456 uninitialized = 0; 2457 2458 ext_debug("remove ext %u:[%d]%d\n", ex_ee_block, 2459 uninitialized, ex_ee_len); 2460 path[depth].p_ext = ex; 2461 2462 a = ex_ee_block > start ? ex_ee_block : start; 2463 b = ex_ee_block+ex_ee_len - 1 < end ? 2464 ex_ee_block+ex_ee_len - 1 : end; 2465 2466 ext_debug(" border %u:%u\n", a, b); 2467 2468 /* If this extent is beyond the end of the hole, skip it */ 2469 if (end < ex_ee_block) { 2470 ex--; 2471 ex_ee_block = le32_to_cpu(ex->ee_block); 2472 ex_ee_len = ext4_ext_get_actual_len(ex); 2473 continue; 2474 } else if (b != ex_ee_block + ex_ee_len - 1) { 2475 EXT4_ERROR_INODE(inode, 2476 "can not handle truncate %u:%u " 2477 "on extent %u:%u", 2478 start, end, ex_ee_block, 2479 ex_ee_block + ex_ee_len - 1); 2480 err = -EIO; 2481 goto out; 2482 } else if (a != ex_ee_block) { 2483 /* remove tail of the extent */ 2484 num = a - ex_ee_block; 2485 } else { 2486 /* remove whole extent: excellent! */ 2487 num = 0; 2488 } 2489 /* 2490 * 3 for leaf, sb, and inode plus 2 (bmap and group 2491 * descriptor) for each block group; assume two block 2492 * groups plus ex_ee_len/blocks_per_block_group for 2493 * the worst case 2494 */ 2495 credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb)); 2496 if (ex == EXT_FIRST_EXTENT(eh)) { 2497 correct_index = 1; 2498 credits += (ext_depth(inode)) + 1; 2499 } 2500 credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb); 2501 2502 err = ext4_ext_truncate_extend_restart(handle, inode, credits); 2503 if (err) 2504 goto out; 2505 2506 err = ext4_ext_get_access(handle, inode, path + depth); 2507 if (err) 2508 goto out; 2509 2510 err = ext4_remove_blocks(handle, inode, ex, partial_cluster, 2511 a, b); 2512 if (err) 2513 goto out; 2514 2515 if (num == 0) 2516 /* this extent is removed; mark slot entirely unused */ 2517 ext4_ext_store_pblock(ex, 0); 2518 2519 ex->ee_len = cpu_to_le16(num); 2520 /* 2521 * Do not mark uninitialized if all the blocks in the 2522 * extent have been removed. 2523 */ 2524 if (uninitialized && num) 2525 ext4_ext_mark_uninitialized(ex); 2526 /* 2527 * If the extent was completely released, 2528 * we need to remove it from the leaf 2529 */ 2530 if (num == 0) { 2531 if (end != EXT_MAX_BLOCKS - 1) { 2532 /* 2533 * For hole punching, we need to scoot all the 2534 * extents up when an extent is removed so that 2535 * we dont have blank extents in the middle 2536 */ 2537 memmove(ex, ex+1, (EXT_LAST_EXTENT(eh) - ex) * 2538 sizeof(struct ext4_extent)); 2539 2540 /* Now get rid of the one at the end */ 2541 memset(EXT_LAST_EXTENT(eh), 0, 2542 sizeof(struct ext4_extent)); 2543 } 2544 le16_add_cpu(&eh->eh_entries, -1); 2545 } else 2546 *partial_cluster = 0; 2547 2548 err = ext4_ext_dirty(handle, inode, path + depth); 2549 if (err) 2550 goto out; 2551 2552 ext_debug("new extent: %u:%u:%llu\n", ex_ee_block, num, 2553 ext4_ext_pblock(ex)); 2554 ex--; 2555 ex_ee_block = le32_to_cpu(ex->ee_block); 2556 ex_ee_len = ext4_ext_get_actual_len(ex); 2557 } 2558 2559 if (correct_index && eh->eh_entries) 2560 err = ext4_ext_correct_indexes(handle, inode, path); 2561 2562 /* 2563 * If there is still a entry in the leaf node, check to see if 2564 * it references the partial cluster. This is the only place 2565 * where it could; if it doesn't, we can free the cluster. 2566 */ 2567 if (*partial_cluster && ex >= EXT_FIRST_EXTENT(eh) && 2568 (EXT4_B2C(sbi, ext4_ext_pblock(ex) + ex_ee_len - 1) != 2569 *partial_cluster)) { 2570 int flags = EXT4_FREE_BLOCKS_FORGET; 2571 2572 if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) 2573 flags |= EXT4_FREE_BLOCKS_METADATA; 2574 2575 ext4_free_blocks(handle, inode, NULL, 2576 EXT4_C2B(sbi, *partial_cluster), 2577 sbi->s_cluster_ratio, flags); 2578 *partial_cluster = 0; 2579 } 2580 2581 /* if this leaf is free, then we should 2582 * remove it from index block above */ 2583 if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL) 2584 err = ext4_ext_rm_idx(handle, inode, path + depth); 2585 2586out: 2587 return err; 2588} 2589 2590/* 2591 * ext4_ext_more_to_rm: 2592 * returns 1 if current index has to be freed (even partial) 2593 */ 2594static int 2595ext4_ext_more_to_rm(struct ext4_ext_path *path) 2596{ 2597 BUG_ON(path->p_idx == NULL); 2598 2599 if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr)) 2600 return 0; 2601 2602 /* 2603 * if truncate on deeper level happened, it wasn't partial, 2604 * so we have to consider current index for truncation 2605 */ 2606 if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block) 2607 return 0; 2608 return 1; 2609} 2610 2611static int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start, 2612 ext4_lblk_t end) 2613{ 2614 struct super_block *sb = inode->i_sb; 2615 int depth = ext_depth(inode); 2616 struct ext4_ext_path *path = NULL; 2617 ext4_fsblk_t partial_cluster = 0; 2618 handle_t *handle; 2619 int i = 0, err; 2620 2621 ext_debug("truncate since %u to %u\n", start, end); 2622 2623 /* probably first extent we're gonna free will be last in block */ 2624 handle = ext4_journal_start(inode, depth + 1); 2625 if (IS_ERR(handle)) 2626 return PTR_ERR(handle); 2627 2628again: 2629 ext4_ext_invalidate_cache(inode); 2630 2631 trace_ext4_ext_remove_space(inode, start, depth); 2632 2633 /* 2634 * Check if we are removing extents inside the extent tree. If that 2635 * is the case, we are going to punch a hole inside the extent tree 2636 * so we have to check whether we need to split the extent covering 2637 * the last block to remove so we can easily remove the part of it 2638 * in ext4_ext_rm_leaf(). 2639 */ 2640 if (end < EXT_MAX_BLOCKS - 1) { 2641 struct ext4_extent *ex; 2642 ext4_lblk_t ee_block; 2643 2644 /* find extent for this block */ 2645 path = ext4_ext_find_extent(inode, end, NULL); 2646 if (IS_ERR(path)) { 2647 ext4_journal_stop(handle); 2648 return PTR_ERR(path); 2649 } 2650 depth = ext_depth(inode); 2651 ex = path[depth].p_ext; 2652 if (!ex) { 2653 ext4_ext_drop_refs(path); 2654 kfree(path); 2655 path = NULL; 2656 goto cont; 2657 } 2658 2659 ee_block = le32_to_cpu(ex->ee_block); 2660 2661 /* 2662 * See if the last block is inside the extent, if so split 2663 * the extent at 'end' block so we can easily remove the 2664 * tail of the first part of the split extent in 2665 * ext4_ext_rm_leaf(). 2666 */ 2667 if (end >= ee_block && 2668 end < ee_block + ext4_ext_get_actual_len(ex) - 1) { 2669 int split_flag = 0; 2670 2671 if (ext4_ext_is_uninitialized(ex)) 2672 split_flag = EXT4_EXT_MARK_UNINIT1 | 2673 EXT4_EXT_MARK_UNINIT2; 2674 2675 /* 2676 * Split the extent in two so that 'end' is the last 2677 * block in the first new extent 2678 */ 2679 err = ext4_split_extent_at(handle, inode, path, 2680 end + 1, split_flag, 2681 EXT4_GET_BLOCKS_PRE_IO | 2682 EXT4_GET_BLOCKS_PUNCH_OUT_EXT); 2683 2684 if (err < 0) 2685 goto out; 2686 } 2687 } 2688cont: 2689 2690 /* 2691 * We start scanning from right side, freeing all the blocks 2692 * after i_size and walking into the tree depth-wise. 2693 */ 2694 depth = ext_depth(inode); 2695 if (path) { 2696 int k = i = depth; 2697 while (--k > 0) 2698 path[k].p_block = 2699 le16_to_cpu(path[k].p_hdr->eh_entries)+1; 2700 } else { 2701 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1), 2702 GFP_NOFS); 2703 if (path == NULL) { 2704 ext4_journal_stop(handle); 2705 return -ENOMEM; 2706 } 2707 path[0].p_depth = depth; 2708 path[0].p_hdr = ext_inode_hdr(inode); 2709 i = 0; 2710 2711 if (ext4_ext_check(inode, path[0].p_hdr, depth)) { 2712 err = -EIO; 2713 goto out; 2714 } 2715 } 2716 err = 0; 2717 2718 while (i >= 0 && err == 0) { 2719 if (i == depth) { 2720 /* this is leaf block */ 2721 err = ext4_ext_rm_leaf(handle, inode, path, 2722 &partial_cluster, start, 2723 end); 2724 /* root level has p_bh == NULL, brelse() eats this */ 2725 brelse(path[i].p_bh); 2726 path[i].p_bh = NULL; 2727 i--; 2728 continue; 2729 } 2730 2731 /* this is index block */ 2732 if (!path[i].p_hdr) { 2733 ext_debug("initialize header\n"); 2734 path[i].p_hdr = ext_block_hdr(path[i].p_bh); 2735 } 2736 2737 if (!path[i].p_idx) { 2738 /* this level hasn't been touched yet */ 2739 path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr); 2740 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1; 2741 ext_debug("init index ptr: hdr 0x%p, num %d\n", 2742 path[i].p_hdr, 2743 le16_to_cpu(path[i].p_hdr->eh_entries)); 2744 } else { 2745 /* we were already here, see at next index */ 2746 path[i].p_idx--; 2747 } 2748 2749 ext_debug("level %d - index, first 0x%p, cur 0x%p\n", 2750 i, EXT_FIRST_INDEX(path[i].p_hdr), 2751 path[i].p_idx); 2752 if (ext4_ext_more_to_rm(path + i)) { 2753 struct buffer_head *bh; 2754 /* go to the next level */ 2755 ext_debug("move to level %d (block %llu)\n", 2756 i + 1, ext4_idx_pblock(path[i].p_idx)); 2757 memset(path + i + 1, 0, sizeof(*path)); 2758 bh = sb_bread(sb, ext4_idx_pblock(path[i].p_idx)); 2759 if (!bh) { 2760 /* should we reset i_size? */ 2761 err = -EIO; 2762 break; 2763 } 2764 if (WARN_ON(i + 1 > depth)) { 2765 err = -EIO; 2766 break; 2767 } 2768 if (ext4_ext_check_block(inode, ext_block_hdr(bh), 2769 depth - i - 1, bh)) { 2770 err = -EIO; 2771 break; 2772 } 2773 path[i + 1].p_bh = bh; 2774 2775 /* save actual number of indexes since this 2776 * number is changed at the next iteration */ 2777 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries); 2778 i++; 2779 } else { 2780 /* we finished processing this index, go up */ 2781 if (path[i].p_hdr->eh_entries == 0 && i > 0) { 2782 /* index is empty, remove it; 2783 * handle must be already prepared by the 2784 * truncatei_leaf() */ 2785 err = ext4_ext_rm_idx(handle, inode, path + i); 2786 } 2787 /* root level has p_bh == NULL, brelse() eats this */ 2788 brelse(path[i].p_bh); 2789 path[i].p_bh = NULL; 2790 i--; 2791 ext_debug("return to level %d\n", i); 2792 } 2793 } 2794 2795 trace_ext4_ext_remove_space_done(inode, start, depth, partial_cluster, 2796 path->p_hdr->eh_entries); 2797 2798 /* If we still have something in the partial cluster and we have removed 2799 * even the first extent, then we should free the blocks in the partial 2800 * cluster as well. */ 2801 if (partial_cluster && path->p_hdr->eh_entries == 0) { 2802 int flags = EXT4_FREE_BLOCKS_FORGET; 2803 2804 if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) 2805 flags |= EXT4_FREE_BLOCKS_METADATA; 2806 2807 ext4_free_blocks(handle, inode, NULL, 2808 EXT4_C2B(EXT4_SB(sb), partial_cluster), 2809 EXT4_SB(sb)->s_cluster_ratio, flags); 2810 partial_cluster = 0; 2811 } 2812 2813 /* TODO: flexible tree reduction should be here */ 2814 if (path->p_hdr->eh_entries == 0) { 2815 /* 2816 * truncate to zero freed all the tree, 2817 * so we need to correct eh_depth 2818 */ 2819 err = ext4_ext_get_access(handle, inode, path); 2820 if (err == 0) { 2821 ext_inode_hdr(inode)->eh_depth = 0; 2822 ext_inode_hdr(inode)->eh_max = 2823 cpu_to_le16(ext4_ext_space_root(inode, 0)); 2824 err = ext4_ext_dirty(handle, inode, path); 2825 } 2826 } 2827out: 2828 ext4_ext_drop_refs(path); 2829 kfree(path); 2830 if (err == -EAGAIN) { 2831 path = NULL; 2832 goto again; 2833 } 2834 ext4_journal_stop(handle); 2835 2836 return err; 2837} 2838 2839/* 2840 * called at mount time 2841 */ 2842void ext4_ext_init(struct super_block *sb) 2843{ 2844 /* 2845 * possible initialization would be here 2846 */ 2847 2848 if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) { 2849#if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS) 2850 printk(KERN_INFO "EXT4-fs: file extents enabled" 2851#ifdef AGGRESSIVE_TEST 2852 ", aggressive tests" 2853#endif 2854#ifdef CHECK_BINSEARCH 2855 ", check binsearch" 2856#endif 2857#ifdef EXTENTS_STATS 2858 ", stats" 2859#endif 2860 "\n"); 2861#endif 2862#ifdef EXTENTS_STATS 2863 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock); 2864 EXT4_SB(sb)->s_ext_min = 1 << 30; 2865 EXT4_SB(sb)->s_ext_max = 0; 2866#endif 2867 } 2868} 2869 2870/* 2871 * called at umount time 2872 */ 2873void ext4_ext_release(struct super_block *sb) 2874{ 2875 if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) 2876 return; 2877 2878#ifdef EXTENTS_STATS 2879 if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) { 2880 struct ext4_sb_info *sbi = EXT4_SB(sb); 2881 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n", 2882 sbi->s_ext_blocks, sbi->s_ext_extents, 2883 sbi->s_ext_blocks / sbi->s_ext_extents); 2884 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n", 2885 sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max); 2886 } 2887#endif 2888} 2889 2890/* FIXME!! we need to try to merge to left or right after zero-out */ 2891static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex) 2892{ 2893 ext4_fsblk_t ee_pblock; 2894 unsigned int ee_len; 2895 int ret; 2896 2897 ee_len = ext4_ext_get_actual_len(ex); 2898 ee_pblock = ext4_ext_pblock(ex); 2899 2900 ret = sb_issue_zeroout(inode->i_sb, ee_pblock, ee_len, GFP_NOFS); 2901 if (ret > 0) 2902 ret = 0; 2903 2904 return ret; 2905} 2906 2907/* 2908 * ext4_split_extent_at() splits an extent at given block. 2909 * 2910 * @handle: the journal handle 2911 * @inode: the file inode 2912 * @path: the path to the extent 2913 * @split: the logical block where the extent is splitted. 2914 * @split_flags: indicates if the extent could be zeroout if split fails, and 2915 * the states(init or uninit) of new extents. 2916 * @flags: flags used to insert new extent to extent tree. 2917 * 2918 * 2919 * Splits extent [a, b] into two extents [a, @split) and [@split, b], states 2920 * of which are deterimined by split_flag. 2921 * 2922 * There are two cases: 2923 * a> the extent are splitted into two extent. 2924 * b> split is not needed, and just mark the extent. 2925 * 2926 * return 0 on success. 2927 */ 2928static int ext4_split_extent_at(handle_t *handle, 2929 struct inode *inode, 2930 struct ext4_ext_path *path, 2931 ext4_lblk_t split, 2932 int split_flag, 2933 int flags) 2934{ 2935 ext4_fsblk_t newblock; 2936 ext4_lblk_t ee_block; 2937 struct ext4_extent *ex, newex, orig_ex; 2938 struct ext4_extent *ex2 = NULL; 2939 unsigned int ee_len, depth; 2940 int err = 0; 2941 2942 ext_debug("ext4_split_extents_at: inode %lu, logical" 2943 "block %llu\n", inode->i_ino, (unsigned long long)split); 2944 2945 ext4_ext_show_leaf(inode, path); 2946 2947 depth = ext_depth(inode); 2948 ex = path[depth].p_ext; 2949 ee_block = le32_to_cpu(ex->ee_block); 2950 ee_len = ext4_ext_get_actual_len(ex); 2951 newblock = split - ee_block + ext4_ext_pblock(ex); 2952 2953 BUG_ON(split < ee_block || split >= (ee_block + ee_len)); 2954 2955 err = ext4_ext_get_access(handle, inode, path + depth); 2956 if (err) 2957 goto out; 2958 2959 if (split == ee_block) { 2960 /* 2961 * case b: block @split is the block that the extent begins with 2962 * then we just change the state of the extent, and splitting 2963 * is not needed. 2964 */ 2965 if (split_flag & EXT4_EXT_MARK_UNINIT2) 2966 ext4_ext_mark_uninitialized(ex); 2967 else 2968 ext4_ext_mark_initialized(ex); 2969 2970 if (!(flags & EXT4_GET_BLOCKS_PRE_IO)) 2971 ext4_ext_try_to_merge(handle, inode, path, ex); 2972 2973 err = ext4_ext_dirty(handle, inode, path + path->p_depth); 2974 goto out; 2975 } 2976 2977 /* case a */ 2978 memcpy(&orig_ex, ex, sizeof(orig_ex)); 2979 ex->ee_len = cpu_to_le16(split - ee_block); 2980 if (split_flag & EXT4_EXT_MARK_UNINIT1) 2981 ext4_ext_mark_uninitialized(ex); 2982 2983 /* 2984 * path may lead to new leaf, not to original leaf any more 2985 * after ext4_ext_insert_extent() returns, 2986 */ 2987 err = ext4_ext_dirty(handle, inode, path + depth); 2988 if (err) 2989 goto fix_extent_len; 2990 2991 ex2 = &newex; 2992 ex2->ee_block = cpu_to_le32(split); 2993 ex2->ee_len = cpu_to_le16(ee_len - (split - ee_block)); 2994 ext4_ext_store_pblock(ex2, newblock); 2995 if (split_flag & EXT4_EXT_MARK_UNINIT2) 2996 ext4_ext_mark_uninitialized(ex2); 2997 2998 err = ext4_ext_insert_extent(handle, inode, path, &newex, flags); 2999 if (err == -ENOSPC && (EXT4_EXT_MAY_ZEROOUT & split_flag)) { 3000 err = ext4_ext_zeroout(inode, &orig_ex); 3001 if (err) 3002 goto fix_extent_len; 3003 /* update the extent length and mark as initialized */ 3004 ex->ee_len = cpu_to_le16(ee_len); 3005 ext4_ext_try_to_merge(handle, inode, path, ex); 3006 err = ext4_ext_dirty(handle, inode, path + path->p_depth); 3007 goto out; 3008 } else if (err) 3009 goto fix_extent_len; 3010 3011out: 3012 ext4_ext_show_leaf(inode, path); 3013 return err; 3014 3015fix_extent_len: 3016 ex->ee_len = orig_ex.ee_len; 3017 ext4_ext_dirty(handle, inode, path + depth); 3018 return err; 3019} 3020 3021/* 3022 * ext4_split_extents() splits an extent and mark extent which is covered 3023 * by @map as split_flags indicates 3024 * 3025 * It may result in splitting the extent into multiple extents (upto three) 3026 * There are three possibilities: 3027 * a> There is no split required 3028 * b> Splits in two extents: Split is happening at either end of the extent 3029 * c> Splits in three extents: Somone is splitting in middle of the extent 3030 * 3031 */ 3032static int ext4_split_extent(handle_t *handle, 3033 struct inode *inode, 3034 struct ext4_ext_path *path, 3035 struct ext4_map_blocks *map, 3036 int split_flag, 3037 int flags) 3038{ 3039 ext4_lblk_t ee_block; 3040 struct ext4_extent *ex; 3041 unsigned int ee_len, depth; 3042 int err = 0; 3043 int uninitialized; 3044 int split_flag1, flags1; 3045 3046 depth = ext_depth(inode); 3047 ex = path[depth].p_ext; 3048 ee_block = le32_to_cpu(ex->ee_block); 3049 ee_len = ext4_ext_get_actual_len(ex); 3050 uninitialized = ext4_ext_is_uninitialized(ex); 3051 3052 if (map->m_lblk + map->m_len < ee_block + ee_len) { 3053 split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT ? 3054 EXT4_EXT_MAY_ZEROOUT : 0; 3055 flags1 = flags | EXT4_GET_BLOCKS_PRE_IO; 3056 if (uninitialized) 3057 split_flag1 |= EXT4_EXT_MARK_UNINIT1 | 3058 EXT4_EXT_MARK_UNINIT2; 3059 err = ext4_split_extent_at(handle, inode, path, 3060 map->m_lblk + map->m_len, split_flag1, flags1); 3061 if (err) 3062 goto out; 3063 } 3064 3065 ext4_ext_drop_refs(path); 3066 path = ext4_ext_find_extent(inode, map->m_lblk, path); 3067 if (IS_ERR(path)) 3068 return PTR_ERR(path); 3069 3070 if (map->m_lblk >= ee_block) { 3071 split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT ? 3072 EXT4_EXT_MAY_ZEROOUT : 0; 3073 if (uninitialized) 3074 split_flag1 |= EXT4_EXT_MARK_UNINIT1; 3075 if (split_flag & EXT4_EXT_MARK_UNINIT2) 3076 split_flag1 |= EXT4_EXT_MARK_UNINIT2; 3077 err = ext4_split_extent_at(handle, inode, path, 3078 map->m_lblk, split_flag1, flags); 3079 if (err) 3080 goto out; 3081 } 3082 3083 ext4_ext_show_leaf(inode, path); 3084out: 3085 return err ? err : map->m_len; 3086} 3087 3088#define EXT4_EXT_ZERO_LEN 7 3089/* 3090 * This function is called by ext4_ext_map_blocks() if someone tries to write 3091 * to an uninitialized extent. It may result in splitting the uninitialized 3092 * extent into multiple extents (up to three - one initialized and two 3093 * uninitialized). 3094 * There are three possibilities: 3095 * a> There is no split required: Entire extent should be initialized 3096 * b> Splits in two extents: Write is happening at either end of the extent 3097 * c> Splits in three extents: Somone is writing in middle of the extent 3098 * 3099 * Pre-conditions: 3100 * - The extent pointed to by 'path' is uninitialized. 3101 * - The extent pointed to by 'path' contains a superset 3102 * of the logical span [map->m_lblk, map->m_lblk + map->m_len). 3103 * 3104 * Post-conditions on success: 3105 * - the returned value is the number of blocks beyond map->l_lblk 3106 * that are allocated and initialized. 3107 * It is guaranteed to be >= map->m_len. 3108 */ 3109static int ext4_ext_convert_to_initialized(handle_t *handle, 3110 struct inode *inode, 3111 struct ext4_map_blocks *map, 3112 struct ext4_ext_path *path) 3113{ 3114 struct ext4_extent_header *eh; 3115 struct ext4_map_blocks split_map; 3116 struct ext4_extent zero_ex; 3117 struct ext4_extent *ex; 3118 ext4_lblk_t ee_block, eof_block; 3119 unsigned int ee_len, depth; 3120 int allocated; 3121 int err = 0; 3122 int split_flag = 0; 3123 3124 ext_debug("ext4_ext_convert_to_initialized: inode %lu, logical" 3125 "block %llu, max_blocks %u\n", inode->i_ino, 3126 (unsigned long long)map->m_lblk, map->m_len); 3127 3128 eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >> 3129 inode->i_sb->s_blocksize_bits; 3130 if (eof_block < map->m_lblk + map->m_len) 3131 eof_block = map->m_lblk + map->m_len; 3132 3133 depth = ext_depth(inode); 3134 eh = path[depth].p_hdr; 3135 ex = path[depth].p_ext; 3136 ee_block = le32_to_cpu(ex->ee_block); 3137 ee_len = ext4_ext_get_actual_len(ex); 3138 allocated = ee_len - (map->m_lblk - ee_block); 3139 3140 trace_ext4_ext_convert_to_initialized_enter(inode, map, ex); 3141 3142 /* Pre-conditions */ 3143 BUG_ON(!ext4_ext_is_uninitialized(ex)); 3144 BUG_ON(!in_range(map->m_lblk, ee_block, ee_len)); 3145 3146 /* 3147 * Attempt to transfer newly initialized blocks from the currently 3148 * uninitialized extent to its left neighbor. This is much cheaper 3149 * than an insertion followed by a merge as those involve costly 3150 * memmove() calls. This is the common case in steady state for 3151 * workloads doing fallocate(FALLOC_FL_KEEP_SIZE) followed by append 3152 * writes. 3153 * 3154 * Limitations of the current logic: 3155 * - L1: we only deal with writes at the start of the extent. 3156 * The approach could be extended to writes at the end 3157 * of the extent but this scenario was deemed less common. 3158 * - L2: we do not deal with writes covering the whole extent. 3159 * This would require removing the extent if the transfer 3160 * is possible. 3161 * - L3: we only attempt to merge with an extent stored in the 3162 * same extent tree node. 3163 */ 3164 if ((map->m_lblk == ee_block) && /*L1*/ 3165 (map->m_len < ee_len) && /*L2*/ 3166 (ex > EXT_FIRST_EXTENT(eh))) { /*L3*/ 3167 struct ext4_extent *prev_ex; 3168 ext4_lblk_t prev_lblk; 3169 ext4_fsblk_t prev_pblk, ee_pblk; 3170 unsigned int prev_len, write_len; 3171 3172 prev_ex = ex - 1; 3173 prev_lblk = le32_to_cpu(prev_ex->ee_block); 3174 prev_len = ext4_ext_get_actual_len(prev_ex); 3175 prev_pblk = ext4_ext_pblock(prev_ex); 3176 ee_pblk = ext4_ext_pblock(ex); 3177 write_len = map->m_len; 3178 3179 /* 3180 * A transfer of blocks from 'ex' to 'prev_ex' is allowed 3181 * upon those conditions: 3182 * - C1: prev_ex is initialized, 3183 * - C2: prev_ex is logically abutting ex, 3184 * - C3: prev_ex is physically abutting ex, 3185 * - C4: prev_ex can receive the additional blocks without 3186 * overflowing the (initialized) length limit. 3187 */ 3188 if ((!ext4_ext_is_uninitialized(prev_ex)) && /*C1*/ 3189 ((prev_lblk + prev_len) == ee_block) && /*C2*/ 3190 ((prev_pblk + prev_len) == ee_pblk) && /*C3*/ 3191 (prev_len < (EXT_INIT_MAX_LEN - write_len))) { /*C4*/ 3192 err = ext4_ext_get_access(handle, inode, path + depth); 3193 if (err) 3194 goto out; 3195 3196 trace_ext4_ext_convert_to_initialized_fastpath(inode, 3197 map, ex, prev_ex); 3198 3199 /* Shift the start of ex by 'write_len' blocks */ 3200 ex->ee_block = cpu_to_le32(ee_block + write_len); 3201 ext4_ext_store_pblock(ex, ee_pblk + write_len); 3202 ex->ee_len = cpu_to_le16(ee_len - write_len); 3203 ext4_ext_mark_uninitialized(ex); /* Restore the flag */ 3204 3205 /* Extend prev_ex by 'write_len' blocks */ 3206 prev_ex->ee_len = cpu_to_le16(prev_len + write_len); 3207 3208 /* Mark the block containing both extents as dirty */ 3209 ext4_ext_dirty(handle, inode, path + depth); 3210 3211 /* Update path to point to the right extent */ 3212 path[depth].p_ext = prev_ex; 3213 3214 /* Result: number of initialized blocks past m_lblk */ 3215 allocated = write_len; 3216 goto out; 3217 } 3218 } 3219 3220 WARN_ON(map->m_lblk < ee_block); 3221 /* 3222 * It is safe to convert extent to initialized via explicit 3223 * zeroout only if extent is fully insde i_size or new_size. 3224 */ 3225 split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0; 3226 3227 /* If extent has less than 2*EXT4_EXT_ZERO_LEN zerout directly */ 3228 if (ee_len <= 2*EXT4_EXT_ZERO_LEN && 3229 (EXT4_EXT_MAY_ZEROOUT & split_flag)) { 3230 err = ext4_ext_zeroout(inode, ex); 3231 if (err) 3232 goto out; 3233 3234 err = ext4_ext_get_access(handle, inode, path + depth); 3235 if (err) 3236 goto out; 3237 ext4_ext_mark_initialized(ex); 3238 ext4_ext_try_to_merge(handle, inode, path, ex); 3239 err = ext4_ext_dirty(handle, inode, path + path->p_depth); 3240 goto out; 3241 } 3242 3243 /* 3244 * four cases: 3245 * 1. split the extent into three extents. 3246 * 2. split the extent into two extents, zeroout the first half. 3247 * 3. split the extent into two extents, zeroout the second half. 3248 * 4. split the extent into two extents with out zeroout. 3249 */ 3250 split_map.m_lblk = map->m_lblk; 3251 split_map.m_len = map->m_len; 3252 3253 if (allocated > map->m_len) { 3254 if (allocated <= EXT4_EXT_ZERO_LEN && 3255 (EXT4_EXT_MAY_ZEROOUT & split_flag)) { 3256 /* case 3 */ 3257 zero_ex.ee_block = 3258 cpu_to_le32(map->m_lblk); 3259 zero_ex.ee_len = cpu_to_le16(allocated); 3260 ext4_ext_store_pblock(&zero_ex, 3261 ext4_ext_pblock(ex) + map->m_lblk - ee_block); 3262 err = ext4_ext_zeroout(inode, &zero_ex); 3263 if (err) 3264 goto out; 3265 split_map.m_lblk = map->m_lblk; 3266 split_map.m_len = allocated; 3267 } else if ((map->m_lblk - ee_block + map->m_len < 3268 EXT4_EXT_ZERO_LEN) && 3269 (EXT4_EXT_MAY_ZEROOUT & split_flag)) { 3270 /* case 2 */ 3271 if (map->m_lblk != ee_block) { 3272 zero_ex.ee_block = ex->ee_block; 3273 zero_ex.ee_len = cpu_to_le16(map->m_lblk - 3274 ee_block); 3275 ext4_ext_store_pblock(&zero_ex, 3276 ext4_ext_pblock(ex)); 3277 err = ext4_ext_zeroout(inode, &zero_ex); 3278 if (err) 3279 goto out; 3280 } 3281 3282 split_map.m_lblk = ee_block; 3283 split_map.m_len = map->m_lblk - ee_block + map->m_len; 3284 allocated = map->m_len; 3285 } 3286 } 3287 3288 allocated = ext4_split_extent(handle, inode, path, 3289 &split_map, split_flag, 0); 3290 if (allocated < 0) 3291 err = allocated; 3292 3293out: 3294 return err ? err : allocated; 3295} 3296 3297/* 3298 * This function is called by ext4_ext_map_blocks() from 3299 * ext4_get_blocks_dio_write() when DIO to write 3300 * to an uninitialized extent. 3301 * 3302 * Writing to an uninitialized extent may result in splitting the uninitialized 3303 * extent into multiple /initialized uninitialized extents (up to three) 3304 * There are three possibilities: 3305 * a> There is no split required: Entire extent should be uninitialized 3306 * b> Splits in two extents: Write is happening at either end of the extent 3307 * c> Splits in three extents: Somone is writing in middle of the extent 3308 * 3309 * One of more index blocks maybe needed if the extent tree grow after 3310 * the uninitialized extent split. To prevent ENOSPC occur at the IO 3311 * complete, we need to split the uninitialized extent before DIO submit 3312 * the IO. The uninitialized extent called at this time will be split 3313 * into three uninitialized extent(at most). After IO complete, the part 3314 * being filled will be convert to initialized by the end_io callback function 3315 * via ext4_convert_unwritten_extents(). 3316 * 3317 * Returns the size of uninitialized extent to be written on success. 3318 */ 3319static int ext4_split_unwritten_extents(handle_t *handle, 3320 struct inode *inode, 3321 struct ext4_map_blocks *map, 3322 struct ext4_ext_path *path, 3323 int flags) 3324{ 3325 ext4_lblk_t eof_block; 3326 ext4_lblk_t ee_block; 3327 struct ext4_extent *ex; 3328 unsigned int ee_len; 3329 int split_flag = 0, depth; 3330 3331 ext_debug("ext4_split_unwritten_extents: inode %lu, logical" 3332 "block %llu, max_blocks %u\n", inode->i_ino, 3333 (unsigned long long)map->m_lblk, map->m_len); 3334 3335 eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >> 3336 inode->i_sb->s_blocksize_bits; 3337 if (eof_block < map->m_lblk + map->m_len) 3338 eof_block = map->m_lblk + map->m_len; 3339 /* 3340 * It is safe to convert extent to initialized via explicit 3341 * zeroout only if extent is fully insde i_size or new_size. 3342 */ 3343 depth = ext_depth(inode); 3344 ex = path[depth].p_ext; 3345 ee_block = le32_to_cpu(ex->ee_block); 3346 ee_len = ext4_ext_get_actual_len(ex); 3347 3348 split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0; 3349 split_flag |= EXT4_EXT_MARK_UNINIT2; 3350 3351 flags |= EXT4_GET_BLOCKS_PRE_IO; 3352 return ext4_split_extent(handle, inode, path, map, split_flag, flags); 3353} 3354 3355static int ext4_convert_unwritten_extents_endio(handle_t *handle, 3356 struct inode *inode, 3357 struct ext4_ext_path *path) 3358{ 3359 struct ext4_extent *ex; 3360 int depth; 3361 int err = 0; 3362 3363 depth = ext_depth(inode); 3364 ex = path[depth].p_ext; 3365 3366 ext_debug("ext4_convert_unwritten_extents_endio: inode %lu, logical" 3367 "block %llu, max_blocks %u\n", inode->i_ino, 3368 (unsigned long long)le32_to_cpu(ex->ee_block), 3369 ext4_ext_get_actual_len(ex)); 3370 3371 err = ext4_ext_get_access(handle, inode, path + depth); 3372 if (err) 3373 goto out; 3374 /* first mark the extent as initialized */ 3375 ext4_ext_mark_initialized(ex); 3376 3377 /* note: ext4_ext_correct_indexes() isn't needed here because 3378 * borders are not changed 3379 */ 3380 ext4_ext_try_to_merge(handle, inode, path, ex); 3381 3382 /* Mark modified extent as dirty */ 3383 err = ext4_ext_dirty(handle, inode, path + path->p_depth); 3384out: 3385 ext4_ext_show_leaf(inode, path); 3386 return err; 3387} 3388 3389static void unmap_underlying_metadata_blocks(struct block_device *bdev, 3390 sector_t block, int count) 3391{ 3392 int i; 3393 for (i = 0; i < count; i++) 3394 unmap_underlying_metadata(bdev, block + i); 3395} 3396 3397/* 3398 * Handle EOFBLOCKS_FL flag, clearing it if necessary 3399 */ 3400static int check_eofblocks_fl(handle_t *handle, struct inode *inode, 3401 ext4_lblk_t lblk, 3402 struct ext4_ext_path *path, 3403 unsigned int len) 3404{ 3405 int i, depth; 3406 struct ext4_extent_header *eh; 3407 struct ext4_extent *last_ex; 3408 3409 if (!ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS)) 3410 return 0; 3411 3412 depth = ext_depth(inode); 3413 eh = path[depth].p_hdr; 3414 3415 /* 3416 * We're going to remove EOFBLOCKS_FL entirely in future so we 3417 * do not care for this case anymore. Simply remove the flag 3418 * if there are no extents. 3419 */ 3420 if (unlikely(!eh->eh_entries)) 3421 goto out; 3422 last_ex = EXT_LAST_EXTENT(eh); 3423 /* 3424 * We should clear the EOFBLOCKS_FL flag if we are writing the 3425 * last block in the last extent in the file. We test this by 3426 * first checking to see if the caller to 3427 * ext4_ext_get_blocks() was interested in the last block (or 3428 * a block beyond the last block) in the current extent. If 3429 * this turns out to be false, we can bail out from this 3430 * function immediately. 3431 */ 3432 if (lblk + len < le32_to_cpu(last_ex->ee_block) + 3433 ext4_ext_get_actual_len(last_ex)) 3434 return 0; 3435 /* 3436 * If the caller does appear to be planning to write at or 3437 * beyond the end of the current extent, we then test to see 3438 * if the current extent is the last extent in the file, by 3439 * checking to make sure it was reached via the rightmost node 3440 * at each level of the tree. 3441 */ 3442 for (i = depth-1; i >= 0; i--) 3443 if (path[i].p_idx != EXT_LAST_INDEX(path[i].p_hdr)) 3444 return 0; 3445out: 3446 ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS); 3447 return ext4_mark_inode_dirty(handle, inode); 3448} 3449 3450/** 3451 * ext4_find_delalloc_range: find delayed allocated block in the given range. 3452 * 3453 * Goes through the buffer heads in the range [lblk_start, lblk_end] and returns 3454 * whether there are any buffers marked for delayed allocation. It returns '1' 3455 * on the first delalloc'ed buffer head found. If no buffer head in the given 3456 * range is marked for delalloc, it returns 0. 3457 * lblk_start should always be <= lblk_end. 3458 * search_hint_reverse is to indicate that searching in reverse from lblk_end to 3459 * lblk_start might be more efficient (i.e., we will likely hit the delalloc'ed 3460 * block sooner). This is useful when blocks are truncated sequentially from 3461 * lblk_start towards lblk_end. 3462 */ 3463static int ext4_find_delalloc_range(struct inode *inode, 3464 ext4_lblk_t lblk_start, 3465 ext4_lblk_t lblk_end, 3466 int search_hint_reverse) 3467{ 3468 struct address_space *mapping = inode->i_mapping; 3469 struct buffer_head *head, *bh = NULL; 3470 struct page *page; 3471 ext4_lblk_t i, pg_lblk; 3472 pgoff_t index; 3473 3474 if (!test_opt(inode->i_sb, DELALLOC)) 3475 return 0; 3476 3477 /* reverse search wont work if fs block size is less than page size */ 3478 if (inode->i_blkbits < PAGE_CACHE_SHIFT) 3479 search_hint_reverse = 0; 3480 3481 if (search_hint_reverse) 3482 i = lblk_end; 3483 else 3484 i = lblk_start; 3485 3486 index = i >> (PAGE_CACHE_SHIFT - inode->i_blkbits); 3487 3488 while ((i >= lblk_start) && (i <= lblk_end)) { 3489 page = find_get_page(mapping, index); 3490 if (!page) 3491 goto nextpage; 3492 3493 if (!page_has_buffers(page)) 3494 goto nextpage; 3495 3496 head = page_buffers(page); 3497 if (!head) 3498 goto nextpage; 3499 3500 bh = head; 3501 pg_lblk = index << (PAGE_CACHE_SHIFT - 3502 inode->i_blkbits); 3503 do { 3504 if (unlikely(pg_lblk < lblk_start)) { 3505 /* 3506 * This is possible when fs block size is less 3507 * than page size and our cluster starts/ends in 3508 * middle of the page. So we need to skip the 3509 * initial few blocks till we reach the 'lblk' 3510 */ 3511 pg_lblk++; 3512 continue; 3513 } 3514 3515 /* Check if the buffer is delayed allocated and that it 3516 * is not yet mapped. (when da-buffers are mapped during 3517 * their writeout, their da_mapped bit is set.) 3518 */ 3519 if (buffer_delay(bh) && !buffer_da_mapped(bh)) { 3520 page_cache_release(page); 3521 trace_ext4_find_delalloc_range(inode, 3522 lblk_start, lblk_end, 3523 search_hint_reverse, 3524 1, i); 3525 return 1; 3526 } 3527 if (search_hint_reverse) 3528 i--; 3529 else 3530 i++; 3531 } while ((i >= lblk_start) && (i <= lblk_end) && 3532 ((bh = bh->b_this_page) != head)); 3533nextpage: 3534 if (page) 3535 page_cache_release(page); 3536 /* 3537 * Move to next page. 'i' will be the first lblk in the next 3538 * page. 3539 */ 3540 if (search_hint_reverse) 3541 index--; 3542 else 3543 index++; 3544 i = index << (PAGE_CACHE_SHIFT - inode->i_blkbits); 3545 } 3546 3547 trace_ext4_find_delalloc_range(inode, lblk_start, lblk_end, 3548 search_hint_reverse, 0, 0); 3549 return 0; 3550} 3551 3552int ext4_find_delalloc_cluster(struct inode *inode, ext4_lblk_t lblk, 3553 int search_hint_reverse) 3554{ 3555 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 3556 ext4_lblk_t lblk_start, lblk_end; 3557 lblk_start = lblk & (~(sbi->s_cluster_ratio - 1)); 3558 lblk_end = lblk_start + sbi->s_cluster_ratio - 1; 3559 3560 return ext4_find_delalloc_range(inode, lblk_start, lblk_end, 3561 search_hint_reverse); 3562} 3563 3564/** 3565 * Determines how many complete clusters (out of those specified by the 'map') 3566 * are under delalloc and were reserved quota for. 3567 * This function is called when we are writing out the blocks that were 3568 * originally written with their allocation delayed, but then the space was 3569 * allocated using fallocate() before the delayed allocation could be resolved. 3570 * The cases to look for are: 3571 * ('=' indicated delayed allocated blocks 3572 * '-' indicates non-delayed allocated blocks) 3573 * (a) partial clusters towards beginning and/or end outside of allocated range 3574 * are not delalloc'ed. 3575 * Ex: 3576 * |----c---=|====c====|====c====|===-c----| 3577 * |++++++ allocated ++++++| 3578 * ==> 4 complete clusters in above example 3579 * 3580 * (b) partial cluster (outside of allocated range) towards either end is 3581 * marked for delayed allocation. In this case, we will exclude that 3582 * cluster. 3583 * Ex: 3584 * |----====c========|========c========| 3585 * |++++++ allocated ++++++| 3586 * ==> 1 complete clusters in above example 3587 * 3588 * Ex: 3589 * |================c================| 3590 * |++++++ allocated ++++++| 3591 * ==> 0 complete clusters in above example 3592 * 3593 * The ext4_da_update_reserve_space will be called only if we 3594 * determine here that there were some "entire" clusters that span 3595 * this 'allocated' range. 3596 * In the non-bigalloc case, this function will just end up returning num_blks 3597 * without ever calling ext4_find_delalloc_range. 3598 */ 3599static unsigned int 3600get_reserved_cluster_alloc(struct inode *inode, ext4_lblk_t lblk_start, 3601 unsigned int num_blks) 3602{ 3603 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 3604 ext4_lblk_t alloc_cluster_start, alloc_cluster_end; 3605 ext4_lblk_t lblk_from, lblk_to, c_offset; 3606 unsigned int allocated_clusters = 0; 3607 3608 alloc_cluster_start = EXT4_B2C(sbi, lblk_start); 3609 alloc_cluster_end = EXT4_B2C(sbi, lblk_start + num_blks - 1); 3610 3611 /* max possible clusters for this allocation */ 3612 allocated_clusters = alloc_cluster_end - alloc_cluster_start + 1; 3613 3614 trace_ext4_get_reserved_cluster_alloc(inode, lblk_start, num_blks); 3615 3616 /* Check towards left side */ 3617 c_offset = lblk_start & (sbi->s_cluster_ratio - 1); 3618 if (c_offset) { 3619 lblk_from = lblk_start & (~(sbi->s_cluster_ratio - 1)); 3620 lblk_to = lblk_from + c_offset - 1; 3621 3622 if (ext4_find_delalloc_range(inode, lblk_from, lblk_to, 0)) 3623 allocated_clusters--; 3624 } 3625 3626 /* Now check towards right. */ 3627 c_offset = (lblk_start + num_blks) & (sbi->s_cluster_ratio - 1); 3628 if (allocated_clusters && c_offset) { 3629 lblk_from = lblk_start + num_blks; 3630 lblk_to = lblk_from + (sbi->s_cluster_ratio - c_offset) - 1; 3631 3632 if (ext4_find_delalloc_range(inode, lblk_from, lblk_to, 0)) 3633 allocated_clusters--; 3634 } 3635 3636 return allocated_clusters; 3637} 3638 3639static int 3640ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode, 3641 struct ext4_map_blocks *map, 3642 struct ext4_ext_path *path, int flags, 3643 unsigned int allocated, ext4_fsblk_t newblock) 3644{ 3645 int ret = 0; 3646 int err = 0; 3647 ext4_io_end_t *io = EXT4_I(inode)->cur_aio_dio; 3648 3649 ext_debug("ext4_ext_handle_uninitialized_extents: inode %lu, logical " 3650 "block %llu, max_blocks %u, flags %x, allocated %u\n", 3651 inode->i_ino, (unsigned long long)map->m_lblk, map->m_len, 3652 flags, allocated); 3653 ext4_ext_show_leaf(inode, path); 3654 3655 trace_ext4_ext_handle_uninitialized_extents(inode, map, allocated, 3656 newblock); 3657 3658 /* get_block() before submit the IO, split the extent */ 3659 if ((flags & EXT4_GET_BLOCKS_PRE_IO)) { 3660 ret = ext4_split_unwritten_extents(handle, inode, map, 3661 path, flags); 3662 /* 3663 * Flag the inode(non aio case) or end_io struct (aio case) 3664 * that this IO needs to conversion to written when IO is 3665 * completed 3666 */ 3667 if (io) 3668 ext4_set_io_unwritten_flag(inode, io); 3669 else 3670 ext4_set_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN); 3671 if (ext4_should_dioread_nolock(inode)) 3672 map->m_flags |= EXT4_MAP_UNINIT; 3673 goto out; 3674 } 3675 /* IO end_io complete, convert the filled extent to written */ 3676 if ((flags & EXT4_GET_BLOCKS_CONVERT)) { 3677 ret = ext4_convert_unwritten_extents_endio(handle, inode, 3678 path); 3679 if (ret >= 0) { 3680 ext4_update_inode_fsync_trans(handle, inode, 1); 3681 err = check_eofblocks_fl(handle, inode, map->m_lblk, 3682 path, map->m_len); 3683 } else 3684 err = ret; 3685 goto out2; 3686 } 3687 /* buffered IO case */ 3688 /* 3689 * repeat fallocate creation request 3690 * we already have an unwritten extent 3691 */ 3692 if (flags & EXT4_GET_BLOCKS_UNINIT_EXT) 3693 goto map_out; 3694 3695 /* buffered READ or buffered write_begin() lookup */ 3696 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) { 3697 /* 3698 * We have blocks reserved already. We 3699 * return allocated blocks so that delalloc 3700 * won't do block reservation for us. But 3701 * the buffer head will be unmapped so that 3702 * a read from the block returns 0s. 3703 */ 3704 map->m_flags |= EXT4_MAP_UNWRITTEN; 3705 goto out1; 3706 } 3707 3708 /* buffered write, writepage time, convert*/ 3709 ret = ext4_ext_convert_to_initialized(handle, inode, map, path); 3710 if (ret >= 0) 3711 ext4_update_inode_fsync_trans(handle, inode, 1); 3712out: 3713 if (ret <= 0) { 3714 err = ret; 3715 goto out2; 3716 } else 3717 allocated = ret; 3718 map->m_flags |= EXT4_MAP_NEW; 3719 /* 3720 * if we allocated more blocks than requested 3721 * we need to make sure we unmap the extra block 3722 * allocated. The actual needed block will get 3723 * unmapped later when we find the buffer_head marked 3724 * new. 3725 */ 3726 if (allocated > map->m_len) { 3727 unmap_underlying_metadata_blocks(inode->i_sb->s_bdev, 3728 newblock + map->m_len, 3729 allocated - map->m_len); 3730 allocated = map->m_len; 3731 } 3732 3733 /* 3734 * If we have done fallocate with the offset that is already 3735 * delayed allocated, we would have block reservation 3736 * and quota reservation done in the delayed write path. 3737 * But fallocate would have already updated quota and block 3738 * count for this offset. So cancel these reservation 3739 */ 3740 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) { 3741 unsigned int reserved_clusters; 3742 reserved_clusters = get_reserved_cluster_alloc(inode, 3743 map->m_lblk, map->m_len); 3744 if (reserved_clusters) 3745 ext4_da_update_reserve_space(inode, 3746 reserved_clusters, 3747 0); 3748 } 3749 3750map_out: 3751 map->m_flags |= EXT4_MAP_MAPPED; 3752 if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0) { 3753 err = check_eofblocks_fl(handle, inode, map->m_lblk, path, 3754 map->m_len); 3755 if (err < 0) 3756 goto out2; 3757 } 3758out1: 3759 if (allocated > map->m_len) 3760 allocated = map->m_len; 3761 ext4_ext_show_leaf(inode, path); 3762 map->m_pblk = newblock; 3763 map->m_len = allocated; 3764out2: 3765 if (path) { 3766 ext4_ext_drop_refs(path); 3767 kfree(path); 3768 } 3769 return err ? err : allocated; 3770} 3771 3772/* 3773 * get_implied_cluster_alloc - check to see if the requested 3774 * allocation (in the map structure) overlaps with a cluster already 3775 * allocated in an extent. 3776 * @sb The filesystem superblock structure 3777 * @map The requested lblk->pblk mapping 3778 * @ex The extent structure which might contain an implied 3779 * cluster allocation 3780 * 3781 * This function is called by ext4_ext_map_blocks() after we failed to 3782 * find blocks that were already in the inode's extent tree. Hence, 3783 * we know that the beginning of the requested region cannot overlap 3784 * the extent from the inode's extent tree. There are three cases we 3785 * want to catch. The first is this case: 3786 * 3787 * |--- cluster # N--| 3788 * |--- extent ---| |---- requested region ---| 3789 * |==========| 3790 * 3791 * The second case that we need to test for is this one: 3792 * 3793 * |--------- cluster # N ----------------| 3794 * |--- requested region --| |------- extent ----| 3795 * |=======================| 3796 * 3797 * The third case is when the requested region lies between two extents 3798 * within the same cluster: 3799 * |------------- cluster # N-------------| 3800 * |----- ex -----| |---- ex_right ----| 3801 * |------ requested region ------| 3802 * |================| 3803 * 3804 * In each of the above cases, we need to set the map->m_pblk and 3805 * map->m_len so it corresponds to the return the extent labelled as 3806 * "|====|" from cluster #N, since it is already in use for data in 3807 * cluster EXT4_B2C(sbi, map->m_lblk). We will then return 1 to 3808 * signal to ext4_ext_map_blocks() that map->m_pblk should be treated 3809 * as a new "allocated" block region. Otherwise, we will return 0 and 3810 * ext4_ext_map_blocks() will then allocate one or more new clusters 3811 * by calling ext4_mb_new_blocks(). 3812 */ 3813static int get_implied_cluster_alloc(struct super_block *sb, 3814 struct ext4_map_blocks *map, 3815 struct ext4_extent *ex, 3816 struct ext4_ext_path *path) 3817{ 3818 struct ext4_sb_info *sbi = EXT4_SB(sb); 3819 ext4_lblk_t c_offset = map->m_lblk & (sbi->s_cluster_ratio-1); 3820 ext4_lblk_t ex_cluster_start, ex_cluster_end; 3821 ext4_lblk_t rr_cluster_start; 3822 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block); 3823 ext4_fsblk_t ee_start = ext4_ext_pblock(ex); 3824 unsigned short ee_len = ext4_ext_get_actual_len(ex); 3825 3826 /* The extent passed in that we are trying to match */ 3827 ex_cluster_start = EXT4_B2C(sbi, ee_block); 3828 ex_cluster_end = EXT4_B2C(sbi, ee_block + ee_len - 1); 3829 3830 /* The requested region passed into ext4_map_blocks() */ 3831 rr_cluster_start = EXT4_B2C(sbi, map->m_lblk); 3832 3833 if ((rr_cluster_start == ex_cluster_end) || 3834 (rr_cluster_start == ex_cluster_start)) { 3835 if (rr_cluster_start == ex_cluster_end) 3836 ee_start += ee_len - 1; 3837 map->m_pblk = (ee_start & ~(sbi->s_cluster_ratio - 1)) + 3838 c_offset; 3839 map->m_len = min(map->m_len, 3840 (unsigned) sbi->s_cluster_ratio - c_offset); 3841 /* 3842 * Check for and handle this case: 3843 * 3844 * |--------- cluster # N-------------| 3845 * |------- extent ----| 3846 * |--- requested region ---| 3847 * |===========| 3848 */ 3849 3850 if (map->m_lblk < ee_block) 3851 map->m_len = min(map->m_len, ee_block - map->m_lblk); 3852 3853 /* 3854 * Check for the case where there is already another allocated 3855 * block to the right of 'ex' but before the end of the cluster. 3856 * 3857 * |------------- cluster # N-------------| 3858 * |----- ex -----| |---- ex_right ----| 3859 * |------ requested region ------| 3860 * |================| 3861 */ 3862 if (map->m_lblk > ee_block) { 3863 ext4_lblk_t next = ext4_ext_next_allocated_block(path); 3864 map->m_len = min(map->m_len, next - map->m_lblk); 3865 } 3866 3867 trace_ext4_get_implied_cluster_alloc_exit(sb, map, 1); 3868 return 1; 3869 } 3870 3871 trace_ext4_get_implied_cluster_alloc_exit(sb, map, 0); 3872 return 0; 3873} 3874 3875 3876/* 3877 * Block allocation/map/preallocation routine for extents based files 3878 * 3879 * 3880 * Need to be called with 3881 * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block 3882 * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem) 3883 * 3884 * return > 0, number of of blocks already mapped/allocated 3885 * if create == 0 and these are pre-allocated blocks 3886 * buffer head is unmapped 3887 * otherwise blocks are mapped 3888 * 3889 * return = 0, if plain look up failed (blocks have not been allocated) 3890 * buffer head is unmapped 3891 * 3892 * return < 0, error case. 3893 */ 3894int ext4_ext_map_blocks(handle_t *handle, struct inode *inode, 3895 struct ext4_map_blocks *map, int flags) 3896{ 3897 struct ext4_ext_path *path = NULL; 3898 struct ext4_extent newex, *ex, *ex2; 3899 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 3900 ext4_fsblk_t newblock = 0; 3901 int free_on_err = 0, err = 0, depth, ret; 3902 unsigned int allocated = 0, offset = 0; 3903 unsigned int allocated_clusters = 0; 3904 struct ext4_allocation_request ar; 3905 ext4_io_end_t *io = EXT4_I(inode)->cur_aio_dio; 3906 ext4_lblk_t cluster_offset; 3907 3908 ext_debug("blocks %u/%u requested for inode %lu\n", 3909 map->m_lblk, map->m_len, inode->i_ino); 3910 trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags); 3911 3912 /* check in cache */ 3913 if (ext4_ext_in_cache(inode, map->m_lblk, &newex)) { 3914 if (!newex.ee_start_lo && !newex.ee_start_hi) { 3915 if ((sbi->s_cluster_ratio > 1) && 3916 ext4_find_delalloc_cluster(inode, map->m_lblk, 0)) 3917 map->m_flags |= EXT4_MAP_FROM_CLUSTER; 3918 3919 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) { 3920 /* 3921 * block isn't allocated yet and 3922 * user doesn't want to allocate it 3923 */ 3924 goto out2; 3925 } 3926 /* we should allocate requested block */ 3927 } else { 3928 /* block is already allocated */ 3929 if (sbi->s_cluster_ratio > 1) 3930 map->m_flags |= EXT4_MAP_FROM_CLUSTER; 3931 newblock = map->m_lblk 3932 - le32_to_cpu(newex.ee_block) 3933 + ext4_ext_pblock(&newex); 3934 /* number of remaining blocks in the extent */ 3935 allocated = ext4_ext_get_actual_len(&newex) - 3936 (map->m_lblk - le32_to_cpu(newex.ee_block)); 3937 goto out; 3938 } 3939 } 3940 3941 /* find extent for this block */ 3942 path = ext4_ext_find_extent(inode, map->m_lblk, NULL); 3943 if (IS_ERR(path)) { 3944 err = PTR_ERR(path); 3945 path = NULL; 3946 goto out2; 3947 } 3948 3949 depth = ext_depth(inode); 3950 3951 /* 3952 * consistent leaf must not be empty; 3953 * this situation is possible, though, _during_ tree modification; 3954 * this is why assert can't be put in ext4_ext_find_extent() 3955 */ 3956 if (unlikely(path[depth].p_ext == NULL && depth != 0)) { 3957 EXT4_ERROR_INODE(inode, "bad extent address " 3958 "lblock: %lu, depth: %d pblock %lld", 3959 (unsigned long) map->m_lblk, depth, 3960 path[depth].p_block); 3961 err = -EIO; 3962 goto out2; 3963 } 3964 3965 ex = path[depth].p_ext; 3966 if (ex) { 3967 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block); 3968 ext4_fsblk_t ee_start = ext4_ext_pblock(ex); 3969 unsigned short ee_len; 3970 3971 /* 3972 * Uninitialized extents are treated as holes, except that 3973 * we split out initialized portions during a write. 3974 */ 3975 ee_len = ext4_ext_get_actual_len(ex); 3976 3977 trace_ext4_ext_show_extent(inode, ee_block, ee_start, ee_len); 3978 3979 /* if found extent covers block, simply return it */ 3980 if (in_range(map->m_lblk, ee_block, ee_len)) { 3981 newblock = map->m_lblk - ee_block + ee_start; 3982 /* number of remaining blocks in the extent */ 3983 allocated = ee_len - (map->m_lblk - ee_block); 3984 ext_debug("%u fit into %u:%d -> %llu\n", map->m_lblk, 3985 ee_block, ee_len, newblock); 3986 3987 /* 3988 * Do not put uninitialized extent 3989 * in the cache 3990 */ 3991 if (!ext4_ext_is_uninitialized(ex)) { 3992 ext4_ext_put_in_cache(inode, ee_block, 3993 ee_len, ee_start); 3994 goto out; 3995 } 3996 ret = ext4_ext_handle_uninitialized_extents( 3997 handle, inode, map, path, flags, 3998 allocated, newblock); 3999 return ret; 4000 } 4001 } 4002 4003 if ((sbi->s_cluster_ratio > 1) && 4004 ext4_find_delalloc_cluster(inode, map->m_lblk, 0)) 4005 map->m_flags |= EXT4_MAP_FROM_CLUSTER; 4006 4007 /* 4008 * requested block isn't allocated yet; 4009 * we couldn't try to create block if create flag is zero 4010 */ 4011 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) { 4012 /* 4013 * put just found gap into cache to speed up 4014 * subsequent requests 4015 */ 4016 ext4_ext_put_gap_in_cache(inode, path, map->m_lblk); 4017 goto out2; 4018 } 4019 4020 /* 4021 * Okay, we need to do block allocation. 4022 */ 4023 map->m_flags &= ~EXT4_MAP_FROM_CLUSTER; 4024 newex.ee_block = cpu_to_le32(map->m_lblk); 4025 cluster_offset = map->m_lblk & (sbi->s_cluster_ratio-1); 4026 4027 /* 4028 * If we are doing bigalloc, check to see if the extent returned 4029 * by ext4_ext_find_extent() implies a cluster we can use. 4030 */ 4031 if (cluster_offset && ex && 4032 get_implied_cluster_alloc(inode->i_sb, map, ex, path)) { 4033 ar.len = allocated = map->m_len; 4034 newblock = map->m_pblk; 4035 map->m_flags |= EXT4_MAP_FROM_CLUSTER; 4036 goto got_allocated_blocks; 4037 } 4038 4039 /* find neighbour allocated blocks */ 4040 ar.lleft = map->m_lblk; 4041 err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft); 4042 if (err) 4043 goto out2; 4044 ar.lright = map->m_lblk; 4045 ex2 = NULL; 4046 err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright, &ex2); 4047 if (err) 4048 goto out2; 4049 4050 /* Check if the extent after searching to the right implies a 4051 * cluster we can use. */ 4052 if ((sbi->s_cluster_ratio > 1) && ex2 && 4053 get_implied_cluster_alloc(inode->i_sb, map, ex2, path)) { 4054 ar.len = allocated = map->m_len; 4055 newblock = map->m_pblk; 4056 map->m_flags |= EXT4_MAP_FROM_CLUSTER; 4057 goto got_allocated_blocks; 4058 } 4059 4060 /* 4061 * See if request is beyond maximum number of blocks we can have in 4062 * a single extent. For an initialized extent this limit is 4063 * EXT_INIT_MAX_LEN and for an uninitialized extent this limit is 4064 * EXT_UNINIT_MAX_LEN. 4065 */ 4066 if (map->m_len > EXT_INIT_MAX_LEN && 4067 !(flags & EXT4_GET_BLOCKS_UNINIT_EXT)) 4068 map->m_len = EXT_INIT_MAX_LEN; 4069 else if (map->m_len > EXT_UNINIT_MAX_LEN && 4070 (flags & EXT4_GET_BLOCKS_UNINIT_EXT)) 4071 map->m_len = EXT_UNINIT_MAX_LEN; 4072 4073 /* Check if we can really insert (m_lblk)::(m_lblk + m_len) extent */ 4074 newex.ee_len = cpu_to_le16(map->m_len); 4075 err = ext4_ext_check_overlap(sbi, inode, &newex, path); 4076 if (err) 4077 allocated = ext4_ext_get_actual_len(&newex); 4078 else 4079 allocated = map->m_len; 4080 4081 /* allocate new block */ 4082 ar.inode = inode; 4083 ar.goal = ext4_ext_find_goal(inode, path, map->m_lblk); 4084 ar.logical = map->m_lblk; 4085 /* 4086 * We calculate the offset from the beginning of the cluster 4087 * for the logical block number, since when we allocate a 4088 * physical cluster, the physical block should start at the 4089 * same offset from the beginning of the cluster. This is 4090 * needed so that future calls to get_implied_cluster_alloc() 4091 * work correctly. 4092 */ 4093 offset = map->m_lblk & (sbi->s_cluster_ratio - 1); 4094 ar.len = EXT4_NUM_B2C(sbi, offset+allocated); 4095 ar.goal -= offset; 4096 ar.logical -= offset; 4097 if (S_ISREG(inode->i_mode)) 4098 ar.flags = EXT4_MB_HINT_DATA; 4099 else 4100 /* disable in-core preallocation for non-regular files */ 4101 ar.flags = 0; 4102 if (flags & EXT4_GET_BLOCKS_NO_NORMALIZE) 4103 ar.flags |= EXT4_MB_HINT_NOPREALLOC; 4104 newblock = ext4_mb_new_blocks(handle, &ar, &err); 4105 if (!newblock) 4106 goto out2; 4107 ext_debug("allocate new block: goal %llu, found %llu/%u\n", 4108 ar.goal, newblock, allocated); 4109 free_on_err = 1; 4110 allocated_clusters = ar.len; 4111 ar.len = EXT4_C2B(sbi, ar.len) - offset; 4112 if (ar.len > allocated) 4113 ar.len = allocated; 4114 4115got_allocated_blocks: 4116 /* try to insert new extent into found leaf and return */ 4117 ext4_ext_store_pblock(&newex, newblock + offset); 4118 newex.ee_len = cpu_to_le16(ar.len); 4119 /* Mark uninitialized */ 4120 if (flags & EXT4_GET_BLOCKS_UNINIT_EXT){ 4121 ext4_ext_mark_uninitialized(&newex); 4122 /* 4123 * io_end structure was created for every IO write to an 4124 * uninitialized extent. To avoid unnecessary conversion, 4125 * here we flag the IO that really needs the conversion. 4126 * For non asycn direct IO case, flag the inode state 4127 * that we need to perform conversion when IO is done. 4128 */ 4129 if ((flags & EXT4_GET_BLOCKS_PRE_IO)) { 4130 if (io) 4131 ext4_set_io_unwritten_flag(inode, io); 4132 else 4133 ext4_set_inode_state(inode, 4134 EXT4_STATE_DIO_UNWRITTEN); 4135 } 4136 if (ext4_should_dioread_nolock(inode)) 4137 map->m_flags |= EXT4_MAP_UNINIT; 4138 } 4139 4140 err = 0; 4141 if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0) 4142 err = check_eofblocks_fl(handle, inode, map->m_lblk, 4143 path, ar.len); 4144 if (!err) 4145 err = ext4_ext_insert_extent(handle, inode, path, 4146 &newex, flags); 4147 if (err && free_on_err) { 4148 int fb_flags = flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE ? 4149 EXT4_FREE_BLOCKS_NO_QUOT_UPDATE : 0; 4150 /* free data blocks we just allocated */ 4151 /* not a good idea to call discard here directly, 4152 * but otherwise we'd need to call it every free() */ 4153 ext4_discard_preallocations(inode); 4154 ext4_free_blocks(handle, inode, NULL, ext4_ext_pblock(&newex), 4155 ext4_ext_get_actual_len(&newex), fb_flags); 4156 goto out2; 4157 } 4158 4159 /* previous routine could use block we allocated */ 4160 newblock = ext4_ext_pblock(&newex); 4161 allocated = ext4_ext_get_actual_len(&newex); 4162 if (allocated > map->m_len) 4163 allocated = map->m_len; 4164 map->m_flags |= EXT4_MAP_NEW; 4165 4166 /* 4167 * Update reserved blocks/metadata blocks after successful 4168 * block allocation which had been deferred till now. 4169 */ 4170 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) { 4171 unsigned int reserved_clusters; 4172 /* 4173 * Check how many clusters we had reserved this allocated range 4174 */ 4175 reserved_clusters = get_reserved_cluster_alloc(inode, 4176 map->m_lblk, allocated); 4177 if (map->m_flags & EXT4_MAP_FROM_CLUSTER) { 4178 if (reserved_clusters) { 4179 /* 4180 * We have clusters reserved for this range. 4181 * But since we are not doing actual allocation 4182 * and are simply using blocks from previously 4183 * allocated cluster, we should release the 4184 * reservation and not claim quota. 4185 */ 4186 ext4_da_update_reserve_space(inode, 4187 reserved_clusters, 0); 4188 } 4189 } else { 4190 BUG_ON(allocated_clusters < reserved_clusters); 4191 /* We will claim quota for all newly allocated blocks.*/ 4192 ext4_da_update_reserve_space(inode, allocated_clusters, 4193 1); 4194 if (reserved_clusters < allocated_clusters) { 4195 struct ext4_inode_info *ei = EXT4_I(inode); 4196 int reservation = allocated_clusters - 4197 reserved_clusters; 4198 /* 4199 * It seems we claimed few clusters outside of 4200 * the range of this allocation. We should give 4201 * it back to the reservation pool. This can 4202 * happen in the following case: 4203 * 4204 * * Suppose s_cluster_ratio is 4 (i.e., each 4205 * cluster has 4 blocks. Thus, the clusters 4206 * are [0-3],[4-7],[8-11]... 4207 * * First comes delayed allocation write for 4208 * logical blocks 10 & 11. Since there were no 4209 * previous delayed allocated blocks in the 4210 * range [8-11], we would reserve 1 cluster 4211 * for this write. 4212 * * Next comes write for logical blocks 3 to 8. 4213 * In this case, we will reserve 2 clusters 4214 * (for [0-3] and [4-7]; and not for [8-11] as 4215 * that range has a delayed allocated blocks. 4216 * Thus total reserved clusters now becomes 3. 4217 * * Now, during the delayed allocation writeout 4218 * time, we will first write blocks [3-8] and 4219 * allocate 3 clusters for writing these 4220 * blocks. Also, we would claim all these 4221 * three clusters above. 4222 * * Now when we come here to writeout the 4223 * blocks [10-11], we would expect to claim 4224 * the reservation of 1 cluster we had made 4225 * (and we would claim it since there are no 4226 * more delayed allocated blocks in the range 4227 * [8-11]. But our reserved cluster count had 4228 * already gone to 0. 4229 * 4230 * Thus, at the step 4 above when we determine 4231 * that there are still some unwritten delayed 4232 * allocated blocks outside of our current 4233 * block range, we should increment the 4234 * reserved clusters count so that when the 4235 * remaining blocks finally gets written, we 4236 * could claim them. 4237 */ 4238 dquot_reserve_block(inode, 4239 EXT4_C2B(sbi, reservation)); 4240 spin_lock(&ei->i_block_reservation_lock); 4241 ei->i_reserved_data_blocks += reservation; 4242 spin_unlock(&ei->i_block_reservation_lock); 4243 } 4244 } 4245 } 4246 4247 /* 4248 * Cache the extent and update transaction to commit on fdatasync only 4249 * when it is _not_ an uninitialized extent. 4250 */ 4251 if ((flags & EXT4_GET_BLOCKS_UNINIT_EXT) == 0) { 4252 ext4_ext_put_in_cache(inode, map->m_lblk, allocated, newblock); 4253 ext4_update_inode_fsync_trans(handle, inode, 1); 4254 } else 4255 ext4_update_inode_fsync_trans(handle, inode, 0); 4256out: 4257 if (allocated > map->m_len) 4258 allocated = map->m_len; 4259 ext4_ext_show_leaf(inode, path); 4260 map->m_flags |= EXT4_MAP_MAPPED; 4261 map->m_pblk = newblock; 4262 map->m_len = allocated; 4263out2: 4264 if (path) { 4265 ext4_ext_drop_refs(path); 4266 kfree(path); 4267 } 4268 4269 trace_ext4_ext_map_blocks_exit(inode, map->m_lblk, 4270 newblock, map->m_len, err ? err : allocated); 4271 4272 return err ? err : allocated; 4273} 4274 4275void ext4_ext_truncate(struct inode *inode) 4276{ 4277 struct address_space *mapping = inode->i_mapping; 4278 struct super_block *sb = inode->i_sb; 4279 ext4_lblk_t last_block; 4280 handle_t *handle; 4281 loff_t page_len; 4282 int err = 0; 4283 4284 /* 4285 * finish any pending end_io work so we won't run the risk of 4286 * converting any truncated blocks to initialized later 4287 */ 4288 ext4_flush_completed_IO(inode); 4289 4290 /* 4291 * probably first extent we're gonna free will be last in block 4292 */ 4293 err = ext4_writepage_trans_blocks(inode); 4294 handle = ext4_journal_start(inode, err); 4295 if (IS_ERR(handle)) 4296 return; 4297 4298 if (inode->i_size % PAGE_CACHE_SIZE != 0) { 4299 page_len = PAGE_CACHE_SIZE - 4300 (inode->i_size & (PAGE_CACHE_SIZE - 1)); 4301 4302 err = ext4_discard_partial_page_buffers(handle, 4303 mapping, inode->i_size, page_len, 0); 4304 4305 if (err) 4306 goto out_stop; 4307 } 4308 4309 if (ext4_orphan_add(handle, inode)) 4310 goto out_stop; 4311 4312 down_write(&EXT4_I(inode)->i_data_sem); 4313 ext4_ext_invalidate_cache(inode); 4314 4315 ext4_discard_preallocations(inode); 4316 4317 /* 4318 * TODO: optimization is possible here. 4319 * Probably we need not scan at all, 4320 * because page truncation is enough. 4321 */ 4322 4323 /* we have to know where to truncate from in crash case */ 4324 EXT4_I(inode)->i_disksize = inode->i_size; 4325 ext4_mark_inode_dirty(handle, inode); 4326 4327 last_block = (inode->i_size + sb->s_blocksize - 1) 4328 >> EXT4_BLOCK_SIZE_BITS(sb); 4329 err = ext4_ext_remove_space(inode, last_block, EXT_MAX_BLOCKS - 1); 4330 4331 /* In a multi-transaction truncate, we only make the final 4332 * transaction synchronous. 4333 */ 4334 if (IS_SYNC(inode)) 4335 ext4_handle_sync(handle); 4336 4337 up_write(&EXT4_I(inode)->i_data_sem); 4338 4339out_stop: 4340 /* 4341 * If this was a simple ftruncate() and the file will remain alive, 4342 * then we need to clear up the orphan record which we created above. 4343 * However, if this was a real unlink then we were called by 4344 * ext4_delete_inode(), and we allow that function to clean up the 4345 * orphan info for us. 4346 */ 4347 if (inode->i_nlink) 4348 ext4_orphan_del(handle, inode); 4349 4350 inode->i_mtime = inode->i_ctime = ext4_current_time(inode); 4351 ext4_mark_inode_dirty(handle, inode); 4352 ext4_journal_stop(handle); 4353} 4354 4355static void ext4_falloc_update_inode(struct inode *inode, 4356 int mode, loff_t new_size, int update_ctime) 4357{ 4358 struct timespec now; 4359 4360 if (update_ctime) { 4361 now = current_fs_time(inode->i_sb); 4362 if (!timespec_equal(&inode->i_ctime, &now)) 4363 inode->i_ctime = now; 4364 } 4365 /* 4366 * Update only when preallocation was requested beyond 4367 * the file size. 4368 */ 4369 if (!(mode & FALLOC_FL_KEEP_SIZE)) { 4370 if (new_size > i_size_read(inode)) 4371 i_size_write(inode, new_size); 4372 if (new_size > EXT4_I(inode)->i_disksize) 4373 ext4_update_i_disksize(inode, new_size); 4374 } else { 4375 /* 4376 * Mark that we allocate beyond EOF so the subsequent truncate 4377 * can proceed even if the new size is the same as i_size. 4378 */ 4379 if (new_size > i_size_read(inode)) 4380 ext4_set_inode_flag(inode, EXT4_INODE_EOFBLOCKS); 4381 } 4382 4383} 4384 4385/* 4386 * preallocate space for a file. This implements ext4's fallocate file 4387 * operation, which gets called from sys_fallocate system call. 4388 * For block-mapped files, posix_fallocate should fall back to the method 4389 * of writing zeroes to the required new blocks (the same behavior which is 4390 * expected for file systems which do not support fallocate() system call). 4391 */ 4392long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len) 4393{ 4394 struct inode *inode = file->f_path.dentry->d_inode; 4395 handle_t *handle; 4396 loff_t new_size; 4397 unsigned int max_blocks; 4398 int ret = 0; 4399 int ret2 = 0; 4400 int retries = 0; 4401 int flags; 4402 struct ext4_map_blocks map; 4403 unsigned int credits, blkbits = inode->i_blkbits; 4404 4405 /* 4406 * currently supporting (pre)allocate mode for extent-based 4407 * files _only_ 4408 */ 4409 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) 4410 return -EOPNOTSUPP; 4411 4412 /* Return error if mode is not supported */ 4413 if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE)) 4414 return -EOPNOTSUPP; 4415 4416 if (mode & FALLOC_FL_PUNCH_HOLE) 4417 return ext4_punch_hole(file, offset, len); 4418 4419 trace_ext4_fallocate_enter(inode, offset, len, mode); 4420 map.m_lblk = offset >> blkbits; 4421 /* 4422 * We can't just convert len to max_blocks because 4423 * If blocksize = 4096 offset = 3072 and len = 2048 4424 */ 4425 max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits) 4426 - map.m_lblk; 4427 /* 4428 * credits to insert 1 extent into extent tree 4429 */ 4430 credits = ext4_chunk_trans_blocks(inode, max_blocks); 4431 mutex_lock(&inode->i_mutex); 4432 ret = inode_newsize_ok(inode, (len + offset)); 4433 if (ret) { 4434 mutex_unlock(&inode->i_mutex); 4435 trace_ext4_fallocate_exit(inode, offset, max_blocks, ret); 4436 return ret; 4437 } 4438 flags = EXT4_GET_BLOCKS_CREATE_UNINIT_EXT; 4439 if (mode & FALLOC_FL_KEEP_SIZE) 4440 flags |= EXT4_GET_BLOCKS_KEEP_SIZE; 4441 /* 4442 * Don't normalize the request if it can fit in one extent so 4443 * that it doesn't get unnecessarily split into multiple 4444 * extents. 4445 */ 4446 if (len <= EXT_UNINIT_MAX_LEN << blkbits) 4447 flags |= EXT4_GET_BLOCKS_NO_NORMALIZE; 4448retry: 4449 while (ret >= 0 && ret < max_blocks) { 4450 map.m_lblk = map.m_lblk + ret; 4451 map.m_len = max_blocks = max_blocks - ret; 4452 handle = ext4_journal_start(inode, credits); 4453 if (IS_ERR(handle)) { 4454 ret = PTR_ERR(handle); 4455 break; 4456 } 4457 ret = ext4_map_blocks(handle, inode, &map, flags); 4458 if (ret <= 0) { 4459#ifdef EXT4FS_DEBUG 4460 WARN_ON(ret <= 0); 4461 printk(KERN_ERR "%s: ext4_ext_map_blocks " 4462 "returned error inode#%lu, block=%u, " 4463 "max_blocks=%u", __func__, 4464 inode->i_ino, map.m_lblk, max_blocks); 4465#endif 4466 ext4_mark_inode_dirty(handle, inode); 4467 ret2 = ext4_journal_stop(handle); 4468 break; 4469 } 4470 if ((map.m_lblk + ret) >= (EXT4_BLOCK_ALIGN(offset + len, 4471 blkbits) >> blkbits)) 4472 new_size = offset + len; 4473 else 4474 new_size = ((loff_t) map.m_lblk + ret) << blkbits; 4475 4476 ext4_falloc_update_inode(inode, mode, new_size, 4477 (map.m_flags & EXT4_MAP_NEW)); 4478 ext4_mark_inode_dirty(handle, inode); 4479 if ((file->f_flags & O_SYNC) && ret >= max_blocks) 4480 ext4_handle_sync(handle); 4481 ret2 = ext4_journal_stop(handle); 4482 if (ret2) 4483 break; 4484 } 4485 if (ret == -ENOSPC && 4486 ext4_should_retry_alloc(inode->i_sb, &retries)) { 4487 ret = 0; 4488 goto retry; 4489 } 4490 mutex_unlock(&inode->i_mutex); 4491 trace_ext4_fallocate_exit(inode, offset, max_blocks, 4492 ret > 0 ? ret2 : ret); 4493 return ret > 0 ? ret2 : ret; 4494} 4495 4496/* 4497 * This function convert a range of blocks to written extents 4498 * The caller of this function will pass the start offset and the size. 4499 * all unwritten extents within this range will be converted to 4500 * written extents. 4501 * 4502 * This function is called from the direct IO end io call back 4503 * function, to convert the fallocated extents after IO is completed. 4504 * Returns 0 on success. 4505 */ 4506int ext4_convert_unwritten_extents(struct inode *inode, loff_t offset, 4507 ssize_t len) 4508{ 4509 handle_t *handle; 4510 unsigned int max_blocks; 4511 int ret = 0; 4512 int ret2 = 0; 4513 struct ext4_map_blocks map; 4514 unsigned int credits, blkbits = inode->i_blkbits; 4515 4516 map.m_lblk = offset >> blkbits; 4517 /* 4518 * We can't just convert len to max_blocks because 4519 * If blocksize = 4096 offset = 3072 and len = 2048 4520 */ 4521 max_blocks = ((EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits) - 4522 map.m_lblk); 4523 /* 4524 * credits to insert 1 extent into extent tree 4525 */ 4526 credits = ext4_chunk_trans_blocks(inode, max_blocks); 4527 while (ret >= 0 && ret < max_blocks) { 4528 map.m_lblk += ret; 4529 map.m_len = (max_blocks -= ret); 4530 handle = ext4_journal_start(inode, credits); 4531 if (IS_ERR(handle)) { 4532 ret = PTR_ERR(handle); 4533 break; 4534 } 4535 ret = ext4_map_blocks(handle, inode, &map, 4536 EXT4_GET_BLOCKS_IO_CONVERT_EXT); 4537 if (ret <= 0) { 4538 WARN_ON(ret <= 0); 4539 ext4_msg(inode->i_sb, KERN_ERR, 4540 "%s:%d: inode #%lu: block %u: len %u: " 4541 "ext4_ext_map_blocks returned %d", 4542 __func__, __LINE__, inode->i_ino, map.m_lblk, 4543 map.m_len, ret); 4544 } 4545 ext4_mark_inode_dirty(handle, inode); 4546 ret2 = ext4_journal_stop(handle); 4547 if (ret <= 0 || ret2 ) 4548 break; 4549 } 4550 return ret > 0 ? ret2 : ret; 4551} 4552 4553/* 4554 * Callback function called for each extent to gather FIEMAP information. 4555 */ 4556static int ext4_ext_fiemap_cb(struct inode *inode, ext4_lblk_t next, 4557 struct ext4_ext_cache *newex, struct ext4_extent *ex, 4558 void *data) 4559{ 4560 __u64 logical; 4561 __u64 physical; 4562 __u64 length; 4563 __u32 flags = 0; 4564 int ret = 0; 4565 struct fiemap_extent_info *fieinfo = data; 4566 unsigned char blksize_bits; 4567 4568 blksize_bits = inode->i_sb->s_blocksize_bits; 4569 logical = (__u64)newex->ec_block << blksize_bits; 4570 4571 if (newex->ec_start == 0) { 4572 /* 4573 * No extent in extent-tree contains block @newex->ec_start, 4574 * then the block may stay in 1)a hole or 2)delayed-extent. 4575 * 4576 * Holes or delayed-extents are processed as follows. 4577 * 1. lookup dirty pages with specified range in pagecache. 4578 * If no page is got, then there is no delayed-extent and 4579 * return with EXT_CONTINUE. 4580 * 2. find the 1st mapped buffer, 4581 * 3. check if the mapped buffer is both in the request range 4582 * and a delayed buffer. If not, there is no delayed-extent, 4583 * then return. 4584 * 4. a delayed-extent is found, the extent will be collected. 4585 */ 4586 ext4_lblk_t end = 0; 4587 pgoff_t last_offset; 4588 pgoff_t offset; 4589 pgoff_t index; 4590 pgoff_t start_index = 0; 4591 struct page **pages = NULL; 4592 struct buffer_head *bh = NULL; 4593 struct buffer_head *head = NULL; 4594 unsigned int nr_pages = PAGE_SIZE / sizeof(struct page *); 4595 4596 pages = kmalloc(PAGE_SIZE, GFP_KERNEL); 4597 if (pages == NULL) 4598 return -ENOMEM; 4599 4600 offset = logical >> PAGE_SHIFT; 4601repeat: 4602 last_offset = offset; 4603 head = NULL; 4604 ret = find_get_pages_tag(inode->i_mapping, &offset, 4605 PAGECACHE_TAG_DIRTY, nr_pages, pages); 4606 4607 if (!(flags & FIEMAP_EXTENT_DELALLOC)) { 4608 /* First time, try to find a mapped buffer. */ 4609 if (ret == 0) { 4610out: 4611 for (index = 0; index < ret; index++) 4612 page_cache_release(pages[index]); 4613 /* just a hole. */ 4614 kfree(pages); 4615 return EXT_CONTINUE; 4616 } 4617 index = 0; 4618 4619next_page: 4620 /* Try to find the 1st mapped buffer. */ 4621 end = ((__u64)pages[index]->index << PAGE_SHIFT) >> 4622 blksize_bits; 4623 if (!page_has_buffers(pages[index])) 4624 goto out; 4625 head = page_buffers(pages[index]); 4626 if (!head) 4627 goto out; 4628 4629 index++; 4630 bh = head; 4631 do { 4632 if (end >= newex->ec_block + 4633 newex->ec_len) 4634 /* The buffer is out of 4635 * the request range. 4636 */ 4637 goto out; 4638 4639 if (buffer_mapped(bh) && 4640 end >= newex->ec_block) { 4641 start_index = index - 1; 4642 /* get the 1st mapped buffer. */ 4643 goto found_mapped_buffer; 4644 } 4645 4646 bh = bh->b_this_page; 4647 end++; 4648 } while (bh != head); 4649 4650 /* No mapped buffer in the range found in this page, 4651 * We need to look up next page. 4652 */ 4653 if (index >= ret) { 4654 /* There is no page left, but we need to limit 4655 * newex->ec_len. 4656 */ 4657 newex->ec_len = end - newex->ec_block; 4658 goto out; 4659 } 4660 goto next_page; 4661 } else { 4662 /*Find contiguous delayed buffers. */ 4663 if (ret > 0 && pages[0]->index == last_offset) 4664 head = page_buffers(pages[0]); 4665 bh = head; 4666 index = 1; 4667 start_index = 0; 4668 } 4669 4670found_mapped_buffer: 4671 if (bh != NULL && buffer_delay(bh)) { 4672 /* 1st or contiguous delayed buffer found. */ 4673 if (!(flags & FIEMAP_EXTENT_DELALLOC)) { 4674 /* 4675 * 1st delayed buffer found, record 4676 * the start of extent. 4677 */ 4678 flags |= FIEMAP_EXTENT_DELALLOC; 4679 newex->ec_block = end; 4680 logical = (__u64)end << blksize_bits; 4681 } 4682 /* Find contiguous delayed buffers. */ 4683 do { 4684 if (!buffer_delay(bh)) 4685 goto found_delayed_extent; 4686 bh = bh->b_this_page; 4687 end++; 4688 } while (bh != head); 4689 4690 for (; index < ret; index++) { 4691 if (!page_has_buffers(pages[index])) { 4692 bh = NULL; 4693 break; 4694 } 4695 head = page_buffers(pages[index]); 4696 if (!head) { 4697 bh = NULL; 4698 break; 4699 } 4700 4701 if (pages[index]->index != 4702 pages[start_index]->index + index 4703 - start_index) { 4704 /* Blocks are not contiguous. */ 4705 bh = NULL; 4706 break; 4707 } 4708 bh = head; 4709 do { 4710 if (!buffer_delay(bh)) 4711 /* Delayed-extent ends. */ 4712 goto found_delayed_extent; 4713 bh = bh->b_this_page; 4714 end++; 4715 } while (bh != head); 4716 } 4717 } else if (!(flags & FIEMAP_EXTENT_DELALLOC)) 4718 /* a hole found. */ 4719 goto out; 4720 4721found_delayed_extent: 4722 newex->ec_len = min(end - newex->ec_block, 4723 (ext4_lblk_t)EXT_INIT_MAX_LEN); 4724 if (ret == nr_pages && bh != NULL && 4725 newex->ec_len < EXT_INIT_MAX_LEN && 4726 buffer_delay(bh)) { 4727 /* Have not collected an extent and continue. */ 4728 for (index = 0; index < ret; index++) 4729 page_cache_release(pages[index]); 4730 goto repeat; 4731 } 4732 4733 for (index = 0; index < ret; index++) 4734 page_cache_release(pages[index]); 4735 kfree(pages); 4736 } 4737 4738 physical = (__u64)newex->ec_start << blksize_bits; 4739 length = (__u64)newex->ec_len << blksize_bits; 4740 4741 if (ex && ext4_ext_is_uninitialized(ex)) 4742 flags |= FIEMAP_EXTENT_UNWRITTEN; 4743 4744 if (next == EXT_MAX_BLOCKS) 4745 flags |= FIEMAP_EXTENT_LAST; 4746 4747 ret = fiemap_fill_next_extent(fieinfo, logical, physical, 4748 length, flags); 4749 if (ret < 0) 4750 return ret; 4751 if (ret == 1) 4752 return EXT_BREAK; 4753 return EXT_CONTINUE; 4754} 4755/* fiemap flags we can handle specified here */ 4756#define EXT4_FIEMAP_FLAGS (FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR) 4757 4758static int ext4_xattr_fiemap(struct inode *inode, 4759 struct fiemap_extent_info *fieinfo) 4760{ 4761 __u64 physical = 0; 4762 __u64 length; 4763 __u32 flags = FIEMAP_EXTENT_LAST; 4764 int blockbits = inode->i_sb->s_blocksize_bits; 4765 int error = 0; 4766 4767 /* in-inode? */ 4768 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) { 4769 struct ext4_iloc iloc; 4770 int offset; /* offset of xattr in inode */ 4771 4772 error = ext4_get_inode_loc(inode, &iloc); 4773 if (error) 4774 return error; 4775 physical = iloc.bh->b_blocknr << blockbits; 4776 offset = EXT4_GOOD_OLD_INODE_SIZE + 4777 EXT4_I(inode)->i_extra_isize; 4778 physical += offset; 4779 length = EXT4_SB(inode->i_sb)->s_inode_size - offset; 4780 flags |= FIEMAP_EXTENT_DATA_INLINE; 4781 brelse(iloc.bh); 4782 } else { /* external block */ 4783 physical = EXT4_I(inode)->i_file_acl << blockbits; 4784 length = inode->i_sb->s_blocksize; 4785 } 4786 4787 if (physical) 4788 error = fiemap_fill_next_extent(fieinfo, 0, physical, 4789 length, flags); 4790 return (error < 0 ? error : 0); 4791} 4792 4793/* 4794 * ext4_ext_punch_hole 4795 * 4796 * Punches a hole of "length" bytes in a file starting 4797 * at byte "offset" 4798 * 4799 * @inode: The inode of the file to punch a hole in 4800 * @offset: The starting byte offset of the hole 4801 * @length: The length of the hole 4802 * 4803 * Returns the number of blocks removed or negative on err 4804 */ 4805int ext4_ext_punch_hole(struct file *file, loff_t offset, loff_t length) 4806{ 4807 struct inode *inode = file->f_path.dentry->d_inode; 4808 struct super_block *sb = inode->i_sb; 4809 ext4_lblk_t first_block, stop_block; 4810 struct address_space *mapping = inode->i_mapping; 4811 handle_t *handle; 4812 loff_t first_page, last_page, page_len; 4813 loff_t first_page_offset, last_page_offset; 4814 int credits, err = 0; 4815 4816 /* No need to punch hole beyond i_size */ 4817 if (offset >= inode->i_size) 4818 return 0; 4819 4820 /* 4821 * If the hole extends beyond i_size, set the hole 4822 * to end after the page that contains i_size 4823 */ 4824 if (offset + length > inode->i_size) { 4825 length = inode->i_size + 4826 PAGE_CACHE_SIZE - (inode->i_size & (PAGE_CACHE_SIZE - 1)) - 4827 offset; 4828 } 4829 4830 first_page = (offset + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 4831 last_page = (offset + length) >> PAGE_CACHE_SHIFT; 4832 4833 first_page_offset = first_page << PAGE_CACHE_SHIFT; 4834 last_page_offset = last_page << PAGE_CACHE_SHIFT; 4835 4836 /* 4837 * Write out all dirty pages to avoid race conditions 4838 * Then release them. 4839 */ 4840 if (mapping->nrpages && mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) { 4841 err = filemap_write_and_wait_range(mapping, 4842 offset, offset + length - 1); 4843 4844 if (err) 4845 return err; 4846 } 4847 4848 /* Now release the pages */ 4849 if (last_page_offset > first_page_offset) { 4850 truncate_pagecache_range(inode, first_page_offset, 4851 last_page_offset - 1); 4852 } 4853 4854 /* finish any pending end_io work */ 4855 ext4_flush_completed_IO(inode); 4856 4857 credits = ext4_writepage_trans_blocks(inode); 4858 handle = ext4_journal_start(inode, credits); 4859 if (IS_ERR(handle)) 4860 return PTR_ERR(handle); 4861 4862 err = ext4_orphan_add(handle, inode); 4863 if (err) 4864 goto out; 4865 4866 /* 4867 * Now we need to zero out the non-page-aligned data in the 4868 * pages at the start and tail of the hole, and unmap the buffer 4869 * heads for the block aligned regions of the page that were 4870 * completely zeroed. 4871 */ 4872 if (first_page > last_page) { 4873 /* 4874 * If the file space being truncated is contained within a page 4875 * just zero out and unmap the middle of that page 4876 */ 4877 err = ext4_discard_partial_page_buffers(handle, 4878 mapping, offset, length, 0); 4879 4880 if (err) 4881 goto out; 4882 } else { 4883 /* 4884 * zero out and unmap the partial page that contains 4885 * the start of the hole 4886 */ 4887 page_len = first_page_offset - offset; 4888 if (page_len > 0) { 4889 err = ext4_discard_partial_page_buffers(handle, mapping, 4890 offset, page_len, 0); 4891 if (err) 4892 goto out; 4893 } 4894 4895 /* 4896 * zero out and unmap the partial page that contains 4897 * the end of the hole 4898 */ 4899 page_len = offset + length - last_page_offset; 4900 if (page_len > 0) { 4901 err = ext4_discard_partial_page_buffers(handle, mapping, 4902 last_page_offset, page_len, 0); 4903 if (err) 4904 goto out; 4905 } 4906 } 4907 4908 /* 4909 * If i_size is contained in the last page, we need to 4910 * unmap and zero the partial page after i_size 4911 */ 4912 if (inode->i_size >> PAGE_CACHE_SHIFT == last_page && 4913 inode->i_size % PAGE_CACHE_SIZE != 0) { 4914 4915 page_len = PAGE_CACHE_SIZE - 4916 (inode->i_size & (PAGE_CACHE_SIZE - 1)); 4917 4918 if (page_len > 0) { 4919 err = ext4_discard_partial_page_buffers(handle, 4920 mapping, inode->i_size, page_len, 0); 4921 4922 if (err) 4923 goto out; 4924 } 4925 } 4926 4927 first_block = (offset + sb->s_blocksize - 1) >> 4928 EXT4_BLOCK_SIZE_BITS(sb); 4929 stop_block = (offset + length) >> EXT4_BLOCK_SIZE_BITS(sb); 4930 4931 /* If there are no blocks to remove, return now */ 4932 if (first_block >= stop_block) 4933 goto out; 4934 4935 down_write(&EXT4_I(inode)->i_data_sem); 4936 ext4_ext_invalidate_cache(inode); 4937 ext4_discard_preallocations(inode); 4938 4939 err = ext4_ext_remove_space(inode, first_block, stop_block - 1); 4940 4941 ext4_ext_invalidate_cache(inode); 4942 ext4_discard_preallocations(inode); 4943 4944 if (IS_SYNC(inode)) 4945 ext4_handle_sync(handle); 4946 4947 up_write(&EXT4_I(inode)->i_data_sem); 4948 4949out: 4950 ext4_orphan_del(handle, inode); 4951 inode->i_mtime = inode->i_ctime = ext4_current_time(inode); 4952 ext4_mark_inode_dirty(handle, inode); 4953 ext4_journal_stop(handle); 4954 return err; 4955} 4956int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, 4957 __u64 start, __u64 len) 4958{ 4959 ext4_lblk_t start_blk; 4960 int error = 0; 4961 4962 /* fallback to generic here if not in extents fmt */ 4963 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) 4964 return generic_block_fiemap(inode, fieinfo, start, len, 4965 ext4_get_block); 4966 4967 if (fiemap_check_flags(fieinfo, EXT4_FIEMAP_FLAGS)) 4968 return -EBADR; 4969 4970 if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) { 4971 error = ext4_xattr_fiemap(inode, fieinfo); 4972 } else { 4973 ext4_lblk_t len_blks; 4974 __u64 last_blk; 4975 4976 start_blk = start >> inode->i_sb->s_blocksize_bits; 4977 last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits; 4978 if (last_blk >= EXT_MAX_BLOCKS) 4979 last_blk = EXT_MAX_BLOCKS-1; 4980 len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1; 4981 4982 /* 4983 * Walk the extent tree gathering extent information. 4984 * ext4_ext_fiemap_cb will push extents back to user. 4985 */ 4986 error = ext4_ext_walk_space(inode, start_blk, len_blks, 4987 ext4_ext_fiemap_cb, fieinfo); 4988 } 4989 4990 return error; 4991} 4992