extents.c revision 63fedaf1c2dd546da22ff5b4ae06e9b4efba5146
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_in_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. 2143 * 2144 * @inode: The files inode 2145 * @block: The block to look for in the cache 2146 * @ex: Pointer where the cached extent will be stored 2147 * if it contains block 2148 * 2149 * Return 0 if cache is invalid; 1 if the cache is valid 2150 */ 2151static int 2152ext4_ext_in_cache(struct inode *inode, ext4_lblk_t block, 2153 struct ext4_extent *ex) 2154{ 2155 struct ext4_ext_cache *cex; 2156 struct ext4_sb_info *sbi; 2157 int ret = 0; 2158 2159 /* 2160 * We borrow i_block_reservation_lock to protect i_cached_extent 2161 */ 2162 spin_lock(&EXT4_I(inode)->i_block_reservation_lock); 2163 cex = &EXT4_I(inode)->i_cached_extent; 2164 sbi = EXT4_SB(inode->i_sb); 2165 2166 /* has cache valid data? */ 2167 if (cex->ec_len == 0) 2168 goto errout; 2169 2170 if (in_range(block, cex->ec_block, cex->ec_len)) { 2171 ex->ee_block = cpu_to_le32(cex->ec_block); 2172 ext4_ext_store_pblock(ex, cex->ec_start); 2173 ex->ee_len = cpu_to_le16(cex->ec_len); 2174 ext_debug("%u cached by %u:%u:%llu\n", 2175 block, 2176 cex->ec_block, cex->ec_len, cex->ec_start); 2177 ret = 1; 2178 } 2179errout: 2180 trace_ext4_ext_in_cache(inode, block, ret); 2181 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock); 2182 return ret; 2183} 2184 2185/* 2186 * ext4_ext_rm_idx: 2187 * removes index from the index block. 2188 */ 2189static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode, 2190 struct ext4_ext_path *path) 2191{ 2192 int err; 2193 ext4_fsblk_t leaf; 2194 2195 /* free index block */ 2196 path--; 2197 leaf = ext4_idx_pblock(path->p_idx); 2198 if (unlikely(path->p_hdr->eh_entries == 0)) { 2199 EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0"); 2200 return -EIO; 2201 } 2202 err = ext4_ext_get_access(handle, inode, path); 2203 if (err) 2204 return err; 2205 2206 if (path->p_idx != EXT_LAST_INDEX(path->p_hdr)) { 2207 int len = EXT_LAST_INDEX(path->p_hdr) - path->p_idx; 2208 len *= sizeof(struct ext4_extent_idx); 2209 memmove(path->p_idx, path->p_idx + 1, len); 2210 } 2211 2212 le16_add_cpu(&path->p_hdr->eh_entries, -1); 2213 err = ext4_ext_dirty(handle, inode, path); 2214 if (err) 2215 return err; 2216 ext_debug("index is empty, remove it, free block %llu\n", leaf); 2217 trace_ext4_ext_rm_idx(inode, leaf); 2218 2219 ext4_free_blocks(handle, inode, NULL, leaf, 1, 2220 EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET); 2221 return err; 2222} 2223 2224/* 2225 * ext4_ext_calc_credits_for_single_extent: 2226 * This routine returns max. credits that needed to insert an extent 2227 * to the extent tree. 2228 * When pass the actual path, the caller should calculate credits 2229 * under i_data_sem. 2230 */ 2231int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks, 2232 struct ext4_ext_path *path) 2233{ 2234 if (path) { 2235 int depth = ext_depth(inode); 2236 int ret = 0; 2237 2238 /* probably there is space in leaf? */ 2239 if (le16_to_cpu(path[depth].p_hdr->eh_entries) 2240 < le16_to_cpu(path[depth].p_hdr->eh_max)) { 2241 2242 /* 2243 * There are some space in the leaf tree, no 2244 * need to account for leaf block credit 2245 * 2246 * bitmaps and block group descriptor blocks 2247 * and other metadata blocks still need to be 2248 * accounted. 2249 */ 2250 /* 1 bitmap, 1 block group descriptor */ 2251 ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb); 2252 return ret; 2253 } 2254 } 2255 2256 return ext4_chunk_trans_blocks(inode, nrblocks); 2257} 2258 2259/* 2260 * How many index/leaf blocks need to change/allocate to modify nrblocks? 2261 * 2262 * if nrblocks are fit in a single extent (chunk flag is 1), then 2263 * in the worse case, each tree level index/leaf need to be changed 2264 * if the tree split due to insert a new extent, then the old tree 2265 * index/leaf need to be updated too 2266 * 2267 * If the nrblocks are discontiguous, they could cause 2268 * the whole tree split more than once, but this is really rare. 2269 */ 2270int ext4_ext_index_trans_blocks(struct inode *inode, int nrblocks, int chunk) 2271{ 2272 int index; 2273 int depth = ext_depth(inode); 2274 2275 if (chunk) 2276 index = depth * 2; 2277 else 2278 index = depth * 3; 2279 2280 return index; 2281} 2282 2283static int ext4_remove_blocks(handle_t *handle, struct inode *inode, 2284 struct ext4_extent *ex, 2285 ext4_fsblk_t *partial_cluster, 2286 ext4_lblk_t from, ext4_lblk_t to) 2287{ 2288 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 2289 unsigned short ee_len = ext4_ext_get_actual_len(ex); 2290 ext4_fsblk_t pblk; 2291 int flags = 0; 2292 2293 if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) 2294 flags |= EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET; 2295 else if (ext4_should_journal_data(inode)) 2296 flags |= EXT4_FREE_BLOCKS_FORGET; 2297 2298 /* 2299 * For bigalloc file systems, we never free a partial cluster 2300 * at the beginning of the extent. Instead, we make a note 2301 * that we tried freeing the cluster, and check to see if we 2302 * need to free it on a subsequent call to ext4_remove_blocks, 2303 * or at the end of the ext4_truncate() operation. 2304 */ 2305 flags |= EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER; 2306 2307 trace_ext4_remove_blocks(inode, ex, from, to, *partial_cluster); 2308 /* 2309 * If we have a partial cluster, and it's different from the 2310 * cluster of the last block, we need to explicitly free the 2311 * partial cluster here. 2312 */ 2313 pblk = ext4_ext_pblock(ex) + ee_len - 1; 2314 if (*partial_cluster && (EXT4_B2C(sbi, pblk) != *partial_cluster)) { 2315 ext4_free_blocks(handle, inode, NULL, 2316 EXT4_C2B(sbi, *partial_cluster), 2317 sbi->s_cluster_ratio, flags); 2318 *partial_cluster = 0; 2319 } 2320 2321#ifdef EXTENTS_STATS 2322 { 2323 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 2324 spin_lock(&sbi->s_ext_stats_lock); 2325 sbi->s_ext_blocks += ee_len; 2326 sbi->s_ext_extents++; 2327 if (ee_len < sbi->s_ext_min) 2328 sbi->s_ext_min = ee_len; 2329 if (ee_len > sbi->s_ext_max) 2330 sbi->s_ext_max = ee_len; 2331 if (ext_depth(inode) > sbi->s_depth_max) 2332 sbi->s_depth_max = ext_depth(inode); 2333 spin_unlock(&sbi->s_ext_stats_lock); 2334 } 2335#endif 2336 if (from >= le32_to_cpu(ex->ee_block) 2337 && to == le32_to_cpu(ex->ee_block) + ee_len - 1) { 2338 /* tail removal */ 2339 ext4_lblk_t num; 2340 2341 num = le32_to_cpu(ex->ee_block) + ee_len - from; 2342 pblk = ext4_ext_pblock(ex) + ee_len - num; 2343 ext_debug("free last %u blocks starting %llu\n", num, pblk); 2344 ext4_free_blocks(handle, inode, NULL, pblk, num, flags); 2345 /* 2346 * If the block range to be freed didn't start at the 2347 * beginning of a cluster, and we removed the entire 2348 * extent, save the partial cluster here, since we 2349 * might need to delete if we determine that the 2350 * truncate operation has removed all of the blocks in 2351 * the cluster. 2352 */ 2353 if (pblk & (sbi->s_cluster_ratio - 1) && 2354 (ee_len == num)) 2355 *partial_cluster = EXT4_B2C(sbi, pblk); 2356 else 2357 *partial_cluster = 0; 2358 } else if (from == le32_to_cpu(ex->ee_block) 2359 && to <= le32_to_cpu(ex->ee_block) + ee_len - 1) { 2360 /* head removal */ 2361 ext4_lblk_t num; 2362 ext4_fsblk_t start; 2363 2364 num = to - from; 2365 start = ext4_ext_pblock(ex); 2366 2367 ext_debug("free first %u blocks starting %llu\n", num, start); 2368 ext4_free_blocks(handle, inode, NULL, start, num, flags); 2369 2370 } else { 2371 printk(KERN_INFO "strange request: removal(2) " 2372 "%u-%u from %u:%u\n", 2373 from, to, le32_to_cpu(ex->ee_block), ee_len); 2374 } 2375 return 0; 2376} 2377 2378 2379/* 2380 * ext4_ext_rm_leaf() Removes the extents associated with the 2381 * blocks appearing between "start" and "end", and splits the extents 2382 * if "start" and "end" appear in the same extent 2383 * 2384 * @handle: The journal handle 2385 * @inode: The files inode 2386 * @path: The path to the leaf 2387 * @start: The first block to remove 2388 * @end: The last block to remove 2389 */ 2390static int 2391ext4_ext_rm_leaf(handle_t *handle, struct inode *inode, 2392 struct ext4_ext_path *path, ext4_fsblk_t *partial_cluster, 2393 ext4_lblk_t start, ext4_lblk_t end) 2394{ 2395 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 2396 int err = 0, correct_index = 0; 2397 int depth = ext_depth(inode), credits; 2398 struct ext4_extent_header *eh; 2399 ext4_lblk_t a, b; 2400 unsigned num; 2401 ext4_lblk_t ex_ee_block; 2402 unsigned short ex_ee_len; 2403 unsigned uninitialized = 0; 2404 struct ext4_extent *ex; 2405 2406 /* the header must be checked already in ext4_ext_remove_space() */ 2407 ext_debug("truncate since %u in leaf to %u\n", start, end); 2408 if (!path[depth].p_hdr) 2409 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh); 2410 eh = path[depth].p_hdr; 2411 if (unlikely(path[depth].p_hdr == NULL)) { 2412 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth); 2413 return -EIO; 2414 } 2415 /* find where to start removing */ 2416 ex = EXT_LAST_EXTENT(eh); 2417 2418 ex_ee_block = le32_to_cpu(ex->ee_block); 2419 ex_ee_len = ext4_ext_get_actual_len(ex); 2420 2421 trace_ext4_ext_rm_leaf(inode, start, ex, *partial_cluster); 2422 2423 while (ex >= EXT_FIRST_EXTENT(eh) && 2424 ex_ee_block + ex_ee_len > start) { 2425 2426 if (ext4_ext_is_uninitialized(ex)) 2427 uninitialized = 1; 2428 else 2429 uninitialized = 0; 2430 2431 ext_debug("remove ext %u:[%d]%d\n", ex_ee_block, 2432 uninitialized, ex_ee_len); 2433 path[depth].p_ext = ex; 2434 2435 a = ex_ee_block > start ? ex_ee_block : start; 2436 b = ex_ee_block+ex_ee_len - 1 < end ? 2437 ex_ee_block+ex_ee_len - 1 : end; 2438 2439 ext_debug(" border %u:%u\n", a, b); 2440 2441 /* If this extent is beyond the end of the hole, skip it */ 2442 if (end < ex_ee_block) { 2443 ex--; 2444 ex_ee_block = le32_to_cpu(ex->ee_block); 2445 ex_ee_len = ext4_ext_get_actual_len(ex); 2446 continue; 2447 } else if (b != ex_ee_block + ex_ee_len - 1) { 2448 EXT4_ERROR_INODE(inode, 2449 "can not handle truncate %u:%u " 2450 "on extent %u:%u", 2451 start, end, ex_ee_block, 2452 ex_ee_block + ex_ee_len - 1); 2453 err = -EIO; 2454 goto out; 2455 } else if (a != ex_ee_block) { 2456 /* remove tail of the extent */ 2457 num = a - ex_ee_block; 2458 } else { 2459 /* remove whole extent: excellent! */ 2460 num = 0; 2461 } 2462 /* 2463 * 3 for leaf, sb, and inode plus 2 (bmap and group 2464 * descriptor) for each block group; assume two block 2465 * groups plus ex_ee_len/blocks_per_block_group for 2466 * the worst case 2467 */ 2468 credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb)); 2469 if (ex == EXT_FIRST_EXTENT(eh)) { 2470 correct_index = 1; 2471 credits += (ext_depth(inode)) + 1; 2472 } 2473 credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb); 2474 2475 err = ext4_ext_truncate_extend_restart(handle, inode, credits); 2476 if (err) 2477 goto out; 2478 2479 err = ext4_ext_get_access(handle, inode, path + depth); 2480 if (err) 2481 goto out; 2482 2483 err = ext4_remove_blocks(handle, inode, ex, partial_cluster, 2484 a, b); 2485 if (err) 2486 goto out; 2487 2488 if (num == 0) 2489 /* this extent is removed; mark slot entirely unused */ 2490 ext4_ext_store_pblock(ex, 0); 2491 2492 ex->ee_len = cpu_to_le16(num); 2493 /* 2494 * Do not mark uninitialized if all the blocks in the 2495 * extent have been removed. 2496 */ 2497 if (uninitialized && num) 2498 ext4_ext_mark_uninitialized(ex); 2499 /* 2500 * If the extent was completely released, 2501 * we need to remove it from the leaf 2502 */ 2503 if (num == 0) { 2504 if (end != EXT_MAX_BLOCKS - 1) { 2505 /* 2506 * For hole punching, we need to scoot all the 2507 * extents up when an extent is removed so that 2508 * we dont have blank extents in the middle 2509 */ 2510 memmove(ex, ex+1, (EXT_LAST_EXTENT(eh) - ex) * 2511 sizeof(struct ext4_extent)); 2512 2513 /* Now get rid of the one at the end */ 2514 memset(EXT_LAST_EXTENT(eh), 0, 2515 sizeof(struct ext4_extent)); 2516 } 2517 le16_add_cpu(&eh->eh_entries, -1); 2518 } else 2519 *partial_cluster = 0; 2520 2521 err = ext4_ext_dirty(handle, inode, path + depth); 2522 if (err) 2523 goto out; 2524 2525 ext_debug("new extent: %u:%u:%llu\n", ex_ee_block, num, 2526 ext4_ext_pblock(ex)); 2527 ex--; 2528 ex_ee_block = le32_to_cpu(ex->ee_block); 2529 ex_ee_len = ext4_ext_get_actual_len(ex); 2530 } 2531 2532 if (correct_index && eh->eh_entries) 2533 err = ext4_ext_correct_indexes(handle, inode, path); 2534 2535 /* 2536 * If there is still a entry in the leaf node, check to see if 2537 * it references the partial cluster. This is the only place 2538 * where it could; if it doesn't, we can free the cluster. 2539 */ 2540 if (*partial_cluster && ex >= EXT_FIRST_EXTENT(eh) && 2541 (EXT4_B2C(sbi, ext4_ext_pblock(ex) + ex_ee_len - 1) != 2542 *partial_cluster)) { 2543 int flags = EXT4_FREE_BLOCKS_FORGET; 2544 2545 if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) 2546 flags |= EXT4_FREE_BLOCKS_METADATA; 2547 2548 ext4_free_blocks(handle, inode, NULL, 2549 EXT4_C2B(sbi, *partial_cluster), 2550 sbi->s_cluster_ratio, flags); 2551 *partial_cluster = 0; 2552 } 2553 2554 /* if this leaf is free, then we should 2555 * remove it from index block above */ 2556 if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL) 2557 err = ext4_ext_rm_idx(handle, inode, path + depth); 2558 2559out: 2560 return err; 2561} 2562 2563/* 2564 * ext4_ext_more_to_rm: 2565 * returns 1 if current index has to be freed (even partial) 2566 */ 2567static int 2568ext4_ext_more_to_rm(struct ext4_ext_path *path) 2569{ 2570 BUG_ON(path->p_idx == NULL); 2571 2572 if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr)) 2573 return 0; 2574 2575 /* 2576 * if truncate on deeper level happened, it wasn't partial, 2577 * so we have to consider current index for truncation 2578 */ 2579 if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block) 2580 return 0; 2581 return 1; 2582} 2583 2584static int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start, 2585 ext4_lblk_t end) 2586{ 2587 struct super_block *sb = inode->i_sb; 2588 int depth = ext_depth(inode); 2589 struct ext4_ext_path *path = NULL; 2590 ext4_fsblk_t partial_cluster = 0; 2591 handle_t *handle; 2592 int i = 0, err; 2593 2594 ext_debug("truncate since %u to %u\n", start, end); 2595 2596 /* probably first extent we're gonna free will be last in block */ 2597 handle = ext4_journal_start(inode, depth + 1); 2598 if (IS_ERR(handle)) 2599 return PTR_ERR(handle); 2600 2601again: 2602 ext4_ext_invalidate_cache(inode); 2603 2604 trace_ext4_ext_remove_space(inode, start, depth); 2605 2606 /* 2607 * Check if we are removing extents inside the extent tree. If that 2608 * is the case, we are going to punch a hole inside the extent tree 2609 * so we have to check whether we need to split the extent covering 2610 * the last block to remove so we can easily remove the part of it 2611 * in ext4_ext_rm_leaf(). 2612 */ 2613 if (end < EXT_MAX_BLOCKS - 1) { 2614 struct ext4_extent *ex; 2615 ext4_lblk_t ee_block; 2616 2617 /* find extent for this block */ 2618 path = ext4_ext_find_extent(inode, end, NULL); 2619 if (IS_ERR(path)) { 2620 ext4_journal_stop(handle); 2621 return PTR_ERR(path); 2622 } 2623 depth = ext_depth(inode); 2624 ex = path[depth].p_ext; 2625 if (!ex) { 2626 ext4_ext_drop_refs(path); 2627 kfree(path); 2628 path = NULL; 2629 goto cont; 2630 } 2631 2632 ee_block = le32_to_cpu(ex->ee_block); 2633 2634 /* 2635 * See if the last block is inside the extent, if so split 2636 * the extent at 'end' block so we can easily remove the 2637 * tail of the first part of the split extent in 2638 * ext4_ext_rm_leaf(). 2639 */ 2640 if (end >= ee_block && 2641 end < ee_block + ext4_ext_get_actual_len(ex) - 1) { 2642 int split_flag = 0; 2643 2644 if (ext4_ext_is_uninitialized(ex)) 2645 split_flag = EXT4_EXT_MARK_UNINIT1 | 2646 EXT4_EXT_MARK_UNINIT2; 2647 2648 /* 2649 * Split the extent in two so that 'end' is the last 2650 * block in the first new extent 2651 */ 2652 err = ext4_split_extent_at(handle, inode, path, 2653 end + 1, split_flag, 2654 EXT4_GET_BLOCKS_PRE_IO | 2655 EXT4_GET_BLOCKS_PUNCH_OUT_EXT); 2656 2657 if (err < 0) 2658 goto out; 2659 } 2660 } 2661cont: 2662 2663 /* 2664 * We start scanning from right side, freeing all the blocks 2665 * after i_size and walking into the tree depth-wise. 2666 */ 2667 depth = ext_depth(inode); 2668 if (path) { 2669 int k = i = depth; 2670 while (--k > 0) 2671 path[k].p_block = 2672 le16_to_cpu(path[k].p_hdr->eh_entries)+1; 2673 } else { 2674 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1), 2675 GFP_NOFS); 2676 if (path == NULL) { 2677 ext4_journal_stop(handle); 2678 return -ENOMEM; 2679 } 2680 path[0].p_depth = depth; 2681 path[0].p_hdr = ext_inode_hdr(inode); 2682 i = 0; 2683 2684 if (ext4_ext_check(inode, path[0].p_hdr, depth)) { 2685 err = -EIO; 2686 goto out; 2687 } 2688 } 2689 err = 0; 2690 2691 while (i >= 0 && err == 0) { 2692 if (i == depth) { 2693 /* this is leaf block */ 2694 err = ext4_ext_rm_leaf(handle, inode, path, 2695 &partial_cluster, start, 2696 end); 2697 /* root level has p_bh == NULL, brelse() eats this */ 2698 brelse(path[i].p_bh); 2699 path[i].p_bh = NULL; 2700 i--; 2701 continue; 2702 } 2703 2704 /* this is index block */ 2705 if (!path[i].p_hdr) { 2706 ext_debug("initialize header\n"); 2707 path[i].p_hdr = ext_block_hdr(path[i].p_bh); 2708 } 2709 2710 if (!path[i].p_idx) { 2711 /* this level hasn't been touched yet */ 2712 path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr); 2713 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1; 2714 ext_debug("init index ptr: hdr 0x%p, num %d\n", 2715 path[i].p_hdr, 2716 le16_to_cpu(path[i].p_hdr->eh_entries)); 2717 } else { 2718 /* we were already here, see at next index */ 2719 path[i].p_idx--; 2720 } 2721 2722 ext_debug("level %d - index, first 0x%p, cur 0x%p\n", 2723 i, EXT_FIRST_INDEX(path[i].p_hdr), 2724 path[i].p_idx); 2725 if (ext4_ext_more_to_rm(path + i)) { 2726 struct buffer_head *bh; 2727 /* go to the next level */ 2728 ext_debug("move to level %d (block %llu)\n", 2729 i + 1, ext4_idx_pblock(path[i].p_idx)); 2730 memset(path + i + 1, 0, sizeof(*path)); 2731 bh = sb_bread(sb, ext4_idx_pblock(path[i].p_idx)); 2732 if (!bh) { 2733 /* should we reset i_size? */ 2734 err = -EIO; 2735 break; 2736 } 2737 if (WARN_ON(i + 1 > depth)) { 2738 err = -EIO; 2739 break; 2740 } 2741 if (ext4_ext_check_block(inode, ext_block_hdr(bh), 2742 depth - i - 1, bh)) { 2743 err = -EIO; 2744 break; 2745 } 2746 path[i + 1].p_bh = bh; 2747 2748 /* save actual number of indexes since this 2749 * number is changed at the next iteration */ 2750 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries); 2751 i++; 2752 } else { 2753 /* we finished processing this index, go up */ 2754 if (path[i].p_hdr->eh_entries == 0 && i > 0) { 2755 /* index is empty, remove it; 2756 * handle must be already prepared by the 2757 * truncatei_leaf() */ 2758 err = ext4_ext_rm_idx(handle, inode, path + i); 2759 } 2760 /* root level has p_bh == NULL, brelse() eats this */ 2761 brelse(path[i].p_bh); 2762 path[i].p_bh = NULL; 2763 i--; 2764 ext_debug("return to level %d\n", i); 2765 } 2766 } 2767 2768 trace_ext4_ext_remove_space_done(inode, start, depth, partial_cluster, 2769 path->p_hdr->eh_entries); 2770 2771 /* If we still have something in the partial cluster and we have removed 2772 * even the first extent, then we should free the blocks in the partial 2773 * cluster as well. */ 2774 if (partial_cluster && path->p_hdr->eh_entries == 0) { 2775 int flags = EXT4_FREE_BLOCKS_FORGET; 2776 2777 if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) 2778 flags |= EXT4_FREE_BLOCKS_METADATA; 2779 2780 ext4_free_blocks(handle, inode, NULL, 2781 EXT4_C2B(EXT4_SB(sb), partial_cluster), 2782 EXT4_SB(sb)->s_cluster_ratio, flags); 2783 partial_cluster = 0; 2784 } 2785 2786 /* TODO: flexible tree reduction should be here */ 2787 if (path->p_hdr->eh_entries == 0) { 2788 /* 2789 * truncate to zero freed all the tree, 2790 * so we need to correct eh_depth 2791 */ 2792 err = ext4_ext_get_access(handle, inode, path); 2793 if (err == 0) { 2794 ext_inode_hdr(inode)->eh_depth = 0; 2795 ext_inode_hdr(inode)->eh_max = 2796 cpu_to_le16(ext4_ext_space_root(inode, 0)); 2797 err = ext4_ext_dirty(handle, inode, path); 2798 } 2799 } 2800out: 2801 ext4_ext_drop_refs(path); 2802 kfree(path); 2803 if (err == -EAGAIN) { 2804 path = NULL; 2805 goto again; 2806 } 2807 ext4_journal_stop(handle); 2808 2809 return err; 2810} 2811 2812/* 2813 * called at mount time 2814 */ 2815void ext4_ext_init(struct super_block *sb) 2816{ 2817 /* 2818 * possible initialization would be here 2819 */ 2820 2821 if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) { 2822#if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS) 2823 printk(KERN_INFO "EXT4-fs: file extents enabled" 2824#ifdef AGGRESSIVE_TEST 2825 ", aggressive tests" 2826#endif 2827#ifdef CHECK_BINSEARCH 2828 ", check binsearch" 2829#endif 2830#ifdef EXTENTS_STATS 2831 ", stats" 2832#endif 2833 "\n"); 2834#endif 2835#ifdef EXTENTS_STATS 2836 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock); 2837 EXT4_SB(sb)->s_ext_min = 1 << 30; 2838 EXT4_SB(sb)->s_ext_max = 0; 2839#endif 2840 } 2841} 2842 2843/* 2844 * called at umount time 2845 */ 2846void ext4_ext_release(struct super_block *sb) 2847{ 2848 if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) 2849 return; 2850 2851#ifdef EXTENTS_STATS 2852 if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) { 2853 struct ext4_sb_info *sbi = EXT4_SB(sb); 2854 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n", 2855 sbi->s_ext_blocks, sbi->s_ext_extents, 2856 sbi->s_ext_blocks / sbi->s_ext_extents); 2857 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n", 2858 sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max); 2859 } 2860#endif 2861} 2862 2863/* FIXME!! we need to try to merge to left or right after zero-out */ 2864static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex) 2865{ 2866 ext4_fsblk_t ee_pblock; 2867 unsigned int ee_len; 2868 int ret; 2869 2870 ee_len = ext4_ext_get_actual_len(ex); 2871 ee_pblock = ext4_ext_pblock(ex); 2872 2873 ret = sb_issue_zeroout(inode->i_sb, ee_pblock, ee_len, GFP_NOFS); 2874 if (ret > 0) 2875 ret = 0; 2876 2877 return ret; 2878} 2879 2880/* 2881 * ext4_split_extent_at() splits an extent at given block. 2882 * 2883 * @handle: the journal handle 2884 * @inode: the file inode 2885 * @path: the path to the extent 2886 * @split: the logical block where the extent is splitted. 2887 * @split_flags: indicates if the extent could be zeroout if split fails, and 2888 * the states(init or uninit) of new extents. 2889 * @flags: flags used to insert new extent to extent tree. 2890 * 2891 * 2892 * Splits extent [a, b] into two extents [a, @split) and [@split, b], states 2893 * of which are deterimined by split_flag. 2894 * 2895 * There are two cases: 2896 * a> the extent are splitted into two extent. 2897 * b> split is not needed, and just mark the extent. 2898 * 2899 * return 0 on success. 2900 */ 2901static int ext4_split_extent_at(handle_t *handle, 2902 struct inode *inode, 2903 struct ext4_ext_path *path, 2904 ext4_lblk_t split, 2905 int split_flag, 2906 int flags) 2907{ 2908 ext4_fsblk_t newblock; 2909 ext4_lblk_t ee_block; 2910 struct ext4_extent *ex, newex, orig_ex; 2911 struct ext4_extent *ex2 = NULL; 2912 unsigned int ee_len, depth; 2913 int err = 0; 2914 2915 ext_debug("ext4_split_extents_at: inode %lu, logical" 2916 "block %llu\n", inode->i_ino, (unsigned long long)split); 2917 2918 ext4_ext_show_leaf(inode, path); 2919 2920 depth = ext_depth(inode); 2921 ex = path[depth].p_ext; 2922 ee_block = le32_to_cpu(ex->ee_block); 2923 ee_len = ext4_ext_get_actual_len(ex); 2924 newblock = split - ee_block + ext4_ext_pblock(ex); 2925 2926 BUG_ON(split < ee_block || split >= (ee_block + ee_len)); 2927 2928 err = ext4_ext_get_access(handle, inode, path + depth); 2929 if (err) 2930 goto out; 2931 2932 if (split == ee_block) { 2933 /* 2934 * case b: block @split is the block that the extent begins with 2935 * then we just change the state of the extent, and splitting 2936 * is not needed. 2937 */ 2938 if (split_flag & EXT4_EXT_MARK_UNINIT2) 2939 ext4_ext_mark_uninitialized(ex); 2940 else 2941 ext4_ext_mark_initialized(ex); 2942 2943 if (!(flags & EXT4_GET_BLOCKS_PRE_IO)) 2944 ext4_ext_try_to_merge(handle, inode, path, ex); 2945 2946 err = ext4_ext_dirty(handle, inode, path + path->p_depth); 2947 goto out; 2948 } 2949 2950 /* case a */ 2951 memcpy(&orig_ex, ex, sizeof(orig_ex)); 2952 ex->ee_len = cpu_to_le16(split - ee_block); 2953 if (split_flag & EXT4_EXT_MARK_UNINIT1) 2954 ext4_ext_mark_uninitialized(ex); 2955 2956 /* 2957 * path may lead to new leaf, not to original leaf any more 2958 * after ext4_ext_insert_extent() returns, 2959 */ 2960 err = ext4_ext_dirty(handle, inode, path + depth); 2961 if (err) 2962 goto fix_extent_len; 2963 2964 ex2 = &newex; 2965 ex2->ee_block = cpu_to_le32(split); 2966 ex2->ee_len = cpu_to_le16(ee_len - (split - ee_block)); 2967 ext4_ext_store_pblock(ex2, newblock); 2968 if (split_flag & EXT4_EXT_MARK_UNINIT2) 2969 ext4_ext_mark_uninitialized(ex2); 2970 2971 err = ext4_ext_insert_extent(handle, inode, path, &newex, flags); 2972 if (err == -ENOSPC && (EXT4_EXT_MAY_ZEROOUT & split_flag)) { 2973 err = ext4_ext_zeroout(inode, &orig_ex); 2974 if (err) 2975 goto fix_extent_len; 2976 /* update the extent length and mark as initialized */ 2977 ex->ee_len = cpu_to_le16(ee_len); 2978 ext4_ext_try_to_merge(handle, inode, path, ex); 2979 err = ext4_ext_dirty(handle, inode, path + path->p_depth); 2980 goto out; 2981 } else if (err) 2982 goto fix_extent_len; 2983 2984out: 2985 ext4_ext_show_leaf(inode, path); 2986 return err; 2987 2988fix_extent_len: 2989 ex->ee_len = orig_ex.ee_len; 2990 ext4_ext_dirty(handle, inode, path + depth); 2991 return err; 2992} 2993 2994/* 2995 * ext4_split_extents() splits an extent and mark extent which is covered 2996 * by @map as split_flags indicates 2997 * 2998 * It may result in splitting the extent into multiple extents (upto three) 2999 * There are three possibilities: 3000 * a> There is no split required 3001 * b> Splits in two extents: Split is happening at either end of the extent 3002 * c> Splits in three extents: Somone is splitting in middle of the extent 3003 * 3004 */ 3005static int ext4_split_extent(handle_t *handle, 3006 struct inode *inode, 3007 struct ext4_ext_path *path, 3008 struct ext4_map_blocks *map, 3009 int split_flag, 3010 int flags) 3011{ 3012 ext4_lblk_t ee_block; 3013 struct ext4_extent *ex; 3014 unsigned int ee_len, depth; 3015 int err = 0; 3016 int uninitialized; 3017 int split_flag1, flags1; 3018 3019 depth = ext_depth(inode); 3020 ex = path[depth].p_ext; 3021 ee_block = le32_to_cpu(ex->ee_block); 3022 ee_len = ext4_ext_get_actual_len(ex); 3023 uninitialized = ext4_ext_is_uninitialized(ex); 3024 3025 if (map->m_lblk + map->m_len < ee_block + ee_len) { 3026 split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT ? 3027 EXT4_EXT_MAY_ZEROOUT : 0; 3028 flags1 = flags | EXT4_GET_BLOCKS_PRE_IO; 3029 if (uninitialized) 3030 split_flag1 |= EXT4_EXT_MARK_UNINIT1 | 3031 EXT4_EXT_MARK_UNINIT2; 3032 err = ext4_split_extent_at(handle, inode, path, 3033 map->m_lblk + map->m_len, split_flag1, flags1); 3034 if (err) 3035 goto out; 3036 } 3037 3038 ext4_ext_drop_refs(path); 3039 path = ext4_ext_find_extent(inode, map->m_lblk, path); 3040 if (IS_ERR(path)) 3041 return PTR_ERR(path); 3042 3043 if (map->m_lblk >= ee_block) { 3044 split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT ? 3045 EXT4_EXT_MAY_ZEROOUT : 0; 3046 if (uninitialized) 3047 split_flag1 |= EXT4_EXT_MARK_UNINIT1; 3048 if (split_flag & EXT4_EXT_MARK_UNINIT2) 3049 split_flag1 |= EXT4_EXT_MARK_UNINIT2; 3050 err = ext4_split_extent_at(handle, inode, path, 3051 map->m_lblk, split_flag1, flags); 3052 if (err) 3053 goto out; 3054 } 3055 3056 ext4_ext_show_leaf(inode, path); 3057out: 3058 return err ? err : map->m_len; 3059} 3060 3061/* 3062 * This function is called by ext4_ext_map_blocks() if someone tries to write 3063 * to an uninitialized extent. It may result in splitting the uninitialized 3064 * extent into multiple extents (up to three - one initialized and two 3065 * uninitialized). 3066 * There are three possibilities: 3067 * a> There is no split required: Entire extent should be initialized 3068 * b> Splits in two extents: Write is happening at either end of the extent 3069 * c> Splits in three extents: Somone is writing in middle of the extent 3070 * 3071 * Pre-conditions: 3072 * - The extent pointed to by 'path' is uninitialized. 3073 * - The extent pointed to by 'path' contains a superset 3074 * of the logical span [map->m_lblk, map->m_lblk + map->m_len). 3075 * 3076 * Post-conditions on success: 3077 * - the returned value is the number of blocks beyond map->l_lblk 3078 * that are allocated and initialized. 3079 * It is guaranteed to be >= map->m_len. 3080 */ 3081static int ext4_ext_convert_to_initialized(handle_t *handle, 3082 struct inode *inode, 3083 struct ext4_map_blocks *map, 3084 struct ext4_ext_path *path) 3085{ 3086 struct ext4_sb_info *sbi; 3087 struct ext4_extent_header *eh; 3088 struct ext4_map_blocks split_map; 3089 struct ext4_extent zero_ex; 3090 struct ext4_extent *ex; 3091 ext4_lblk_t ee_block, eof_block; 3092 unsigned int ee_len, depth; 3093 int allocated, max_zeroout = 0; 3094 int err = 0; 3095 int split_flag = 0; 3096 3097 ext_debug("ext4_ext_convert_to_initialized: inode %lu, logical" 3098 "block %llu, max_blocks %u\n", inode->i_ino, 3099 (unsigned long long)map->m_lblk, map->m_len); 3100 3101 sbi = EXT4_SB(inode->i_sb); 3102 eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >> 3103 inode->i_sb->s_blocksize_bits; 3104 if (eof_block < map->m_lblk + map->m_len) 3105 eof_block = map->m_lblk + map->m_len; 3106 3107 depth = ext_depth(inode); 3108 eh = path[depth].p_hdr; 3109 ex = path[depth].p_ext; 3110 ee_block = le32_to_cpu(ex->ee_block); 3111 ee_len = ext4_ext_get_actual_len(ex); 3112 allocated = ee_len - (map->m_lblk - ee_block); 3113 3114 trace_ext4_ext_convert_to_initialized_enter(inode, map, ex); 3115 3116 /* Pre-conditions */ 3117 BUG_ON(!ext4_ext_is_uninitialized(ex)); 3118 BUG_ON(!in_range(map->m_lblk, ee_block, ee_len)); 3119 3120 /* 3121 * Attempt to transfer newly initialized blocks from the currently 3122 * uninitialized extent to its left neighbor. This is much cheaper 3123 * than an insertion followed by a merge as those involve costly 3124 * memmove() calls. This is the common case in steady state for 3125 * workloads doing fallocate(FALLOC_FL_KEEP_SIZE) followed by append 3126 * writes. 3127 * 3128 * Limitations of the current logic: 3129 * - L1: we only deal with writes at the start of the extent. 3130 * The approach could be extended to writes at the end 3131 * of the extent but this scenario was deemed less common. 3132 * - L2: we do not deal with writes covering the whole extent. 3133 * This would require removing the extent if the transfer 3134 * is possible. 3135 * - L3: we only attempt to merge with an extent stored in the 3136 * same extent tree node. 3137 */ 3138 if ((map->m_lblk == ee_block) && /*L1*/ 3139 (map->m_len < ee_len) && /*L2*/ 3140 (ex > EXT_FIRST_EXTENT(eh))) { /*L3*/ 3141 struct ext4_extent *prev_ex; 3142 ext4_lblk_t prev_lblk; 3143 ext4_fsblk_t prev_pblk, ee_pblk; 3144 unsigned int prev_len, write_len; 3145 3146 prev_ex = ex - 1; 3147 prev_lblk = le32_to_cpu(prev_ex->ee_block); 3148 prev_len = ext4_ext_get_actual_len(prev_ex); 3149 prev_pblk = ext4_ext_pblock(prev_ex); 3150 ee_pblk = ext4_ext_pblock(ex); 3151 write_len = map->m_len; 3152 3153 /* 3154 * A transfer of blocks from 'ex' to 'prev_ex' is allowed 3155 * upon those conditions: 3156 * - C1: prev_ex is initialized, 3157 * - C2: prev_ex is logically abutting ex, 3158 * - C3: prev_ex is physically abutting ex, 3159 * - C4: prev_ex can receive the additional blocks without 3160 * overflowing the (initialized) length limit. 3161 */ 3162 if ((!ext4_ext_is_uninitialized(prev_ex)) && /*C1*/ 3163 ((prev_lblk + prev_len) == ee_block) && /*C2*/ 3164 ((prev_pblk + prev_len) == ee_pblk) && /*C3*/ 3165 (prev_len < (EXT_INIT_MAX_LEN - write_len))) { /*C4*/ 3166 err = ext4_ext_get_access(handle, inode, path + depth); 3167 if (err) 3168 goto out; 3169 3170 trace_ext4_ext_convert_to_initialized_fastpath(inode, 3171 map, ex, prev_ex); 3172 3173 /* Shift the start of ex by 'write_len' blocks */ 3174 ex->ee_block = cpu_to_le32(ee_block + write_len); 3175 ext4_ext_store_pblock(ex, ee_pblk + write_len); 3176 ex->ee_len = cpu_to_le16(ee_len - write_len); 3177 ext4_ext_mark_uninitialized(ex); /* Restore the flag */ 3178 3179 /* Extend prev_ex by 'write_len' blocks */ 3180 prev_ex->ee_len = cpu_to_le16(prev_len + write_len); 3181 3182 /* Mark the block containing both extents as dirty */ 3183 ext4_ext_dirty(handle, inode, path + depth); 3184 3185 /* Update path to point to the right extent */ 3186 path[depth].p_ext = prev_ex; 3187 3188 /* Result: number of initialized blocks past m_lblk */ 3189 allocated = write_len; 3190 goto out; 3191 } 3192 } 3193 3194 WARN_ON(map->m_lblk < ee_block); 3195 /* 3196 * It is safe to convert extent to initialized via explicit 3197 * zeroout only if extent is fully insde i_size or new_size. 3198 */ 3199 split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0; 3200 3201 if (EXT4_EXT_MAY_ZEROOUT & split_flag) 3202 max_zeroout = sbi->s_extent_max_zeroout_kb >> 3203 inode->i_sb->s_blocksize_bits; 3204 3205 /* If extent is less than s_max_zeroout_kb, zeroout directly */ 3206 if (max_zeroout && (ee_len <= max_zeroout)) { 3207 err = ext4_ext_zeroout(inode, ex); 3208 if (err) 3209 goto out; 3210 3211 err = ext4_ext_get_access(handle, inode, path + depth); 3212 if (err) 3213 goto out; 3214 ext4_ext_mark_initialized(ex); 3215 ext4_ext_try_to_merge(handle, inode, path, ex); 3216 err = ext4_ext_dirty(handle, inode, path + path->p_depth); 3217 goto out; 3218 } 3219 3220 /* 3221 * four cases: 3222 * 1. split the extent into three extents. 3223 * 2. split the extent into two extents, zeroout the first half. 3224 * 3. split the extent into two extents, zeroout the second half. 3225 * 4. split the extent into two extents with out zeroout. 3226 */ 3227 split_map.m_lblk = map->m_lblk; 3228 split_map.m_len = map->m_len; 3229 3230 if (max_zeroout && (allocated > map->m_len)) { 3231 if (allocated <= max_zeroout) { 3232 /* case 3 */ 3233 zero_ex.ee_block = 3234 cpu_to_le32(map->m_lblk); 3235 zero_ex.ee_len = cpu_to_le16(allocated); 3236 ext4_ext_store_pblock(&zero_ex, 3237 ext4_ext_pblock(ex) + map->m_lblk - ee_block); 3238 err = ext4_ext_zeroout(inode, &zero_ex); 3239 if (err) 3240 goto out; 3241 split_map.m_lblk = map->m_lblk; 3242 split_map.m_len = allocated; 3243 } else if (map->m_lblk - ee_block + map->m_len < max_zeroout) { 3244 /* case 2 */ 3245 if (map->m_lblk != ee_block) { 3246 zero_ex.ee_block = ex->ee_block; 3247 zero_ex.ee_len = cpu_to_le16(map->m_lblk - 3248 ee_block); 3249 ext4_ext_store_pblock(&zero_ex, 3250 ext4_ext_pblock(ex)); 3251 err = ext4_ext_zeroout(inode, &zero_ex); 3252 if (err) 3253 goto out; 3254 } 3255 3256 split_map.m_lblk = ee_block; 3257 split_map.m_len = map->m_lblk - ee_block + map->m_len; 3258 allocated = map->m_len; 3259 } 3260 } 3261 3262 allocated = ext4_split_extent(handle, inode, path, 3263 &split_map, split_flag, 0); 3264 if (allocated < 0) 3265 err = allocated; 3266 3267out: 3268 return err ? err : allocated; 3269} 3270 3271/* 3272 * This function is called by ext4_ext_map_blocks() from 3273 * ext4_get_blocks_dio_write() when DIO to write 3274 * to an uninitialized extent. 3275 * 3276 * Writing to an uninitialized extent may result in splitting the uninitialized 3277 * extent into multiple initialized/uninitialized extents (up to three) 3278 * There are three possibilities: 3279 * a> There is no split required: Entire extent should be uninitialized 3280 * b> Splits in two extents: Write is happening at either end of the extent 3281 * c> Splits in three extents: Somone is writing in middle of the extent 3282 * 3283 * One of more index blocks maybe needed if the extent tree grow after 3284 * the uninitialized extent split. To prevent ENOSPC occur at the IO 3285 * complete, we need to split the uninitialized extent before DIO submit 3286 * the IO. The uninitialized extent called at this time will be split 3287 * into three uninitialized extent(at most). After IO complete, the part 3288 * being filled will be convert to initialized by the end_io callback function 3289 * via ext4_convert_unwritten_extents(). 3290 * 3291 * Returns the size of uninitialized extent to be written on success. 3292 */ 3293static int ext4_split_unwritten_extents(handle_t *handle, 3294 struct inode *inode, 3295 struct ext4_map_blocks *map, 3296 struct ext4_ext_path *path, 3297 int flags) 3298{ 3299 ext4_lblk_t eof_block; 3300 ext4_lblk_t ee_block; 3301 struct ext4_extent *ex; 3302 unsigned int ee_len; 3303 int split_flag = 0, depth; 3304 3305 ext_debug("ext4_split_unwritten_extents: inode %lu, logical" 3306 "block %llu, max_blocks %u\n", inode->i_ino, 3307 (unsigned long long)map->m_lblk, map->m_len); 3308 3309 eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >> 3310 inode->i_sb->s_blocksize_bits; 3311 if (eof_block < map->m_lblk + map->m_len) 3312 eof_block = map->m_lblk + map->m_len; 3313 /* 3314 * It is safe to convert extent to initialized via explicit 3315 * zeroout only if extent is fully insde i_size or new_size. 3316 */ 3317 depth = ext_depth(inode); 3318 ex = path[depth].p_ext; 3319 ee_block = le32_to_cpu(ex->ee_block); 3320 ee_len = ext4_ext_get_actual_len(ex); 3321 3322 split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0; 3323 split_flag |= EXT4_EXT_MARK_UNINIT2; 3324 3325 flags |= EXT4_GET_BLOCKS_PRE_IO; 3326 return ext4_split_extent(handle, inode, path, map, split_flag, flags); 3327} 3328 3329static int ext4_convert_unwritten_extents_endio(handle_t *handle, 3330 struct inode *inode, 3331 struct ext4_ext_path *path) 3332{ 3333 struct ext4_extent *ex; 3334 int depth; 3335 int err = 0; 3336 3337 depth = ext_depth(inode); 3338 ex = path[depth].p_ext; 3339 3340 ext_debug("ext4_convert_unwritten_extents_endio: inode %lu, logical" 3341 "block %llu, max_blocks %u\n", inode->i_ino, 3342 (unsigned long long)le32_to_cpu(ex->ee_block), 3343 ext4_ext_get_actual_len(ex)); 3344 3345 err = ext4_ext_get_access(handle, inode, path + depth); 3346 if (err) 3347 goto out; 3348 /* first mark the extent as initialized */ 3349 ext4_ext_mark_initialized(ex); 3350 3351 /* note: ext4_ext_correct_indexes() isn't needed here because 3352 * borders are not changed 3353 */ 3354 ext4_ext_try_to_merge(handle, inode, path, ex); 3355 3356 /* Mark modified extent as dirty */ 3357 err = ext4_ext_dirty(handle, inode, path + path->p_depth); 3358out: 3359 ext4_ext_show_leaf(inode, path); 3360 return err; 3361} 3362 3363static void unmap_underlying_metadata_blocks(struct block_device *bdev, 3364 sector_t block, int count) 3365{ 3366 int i; 3367 for (i = 0; i < count; i++) 3368 unmap_underlying_metadata(bdev, block + i); 3369} 3370 3371/* 3372 * Handle EOFBLOCKS_FL flag, clearing it if necessary 3373 */ 3374static int check_eofblocks_fl(handle_t *handle, struct inode *inode, 3375 ext4_lblk_t lblk, 3376 struct ext4_ext_path *path, 3377 unsigned int len) 3378{ 3379 int i, depth; 3380 struct ext4_extent_header *eh; 3381 struct ext4_extent *last_ex; 3382 3383 if (!ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS)) 3384 return 0; 3385 3386 depth = ext_depth(inode); 3387 eh = path[depth].p_hdr; 3388 3389 /* 3390 * We're going to remove EOFBLOCKS_FL entirely in future so we 3391 * do not care for this case anymore. Simply remove the flag 3392 * if there are no extents. 3393 */ 3394 if (unlikely(!eh->eh_entries)) 3395 goto out; 3396 last_ex = EXT_LAST_EXTENT(eh); 3397 /* 3398 * We should clear the EOFBLOCKS_FL flag if we are writing the 3399 * last block in the last extent in the file. We test this by 3400 * first checking to see if the caller to 3401 * ext4_ext_get_blocks() was interested in the last block (or 3402 * a block beyond the last block) in the current extent. If 3403 * this turns out to be false, we can bail out from this 3404 * function immediately. 3405 */ 3406 if (lblk + len < le32_to_cpu(last_ex->ee_block) + 3407 ext4_ext_get_actual_len(last_ex)) 3408 return 0; 3409 /* 3410 * If the caller does appear to be planning to write at or 3411 * beyond the end of the current extent, we then test to see 3412 * if the current extent is the last extent in the file, by 3413 * checking to make sure it was reached via the rightmost node 3414 * at each level of the tree. 3415 */ 3416 for (i = depth-1; i >= 0; i--) 3417 if (path[i].p_idx != EXT_LAST_INDEX(path[i].p_hdr)) 3418 return 0; 3419out: 3420 ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS); 3421 return ext4_mark_inode_dirty(handle, inode); 3422} 3423 3424/** 3425 * ext4_find_delalloc_range: find delayed allocated block in the given range. 3426 * 3427 * Goes through the buffer heads in the range [lblk_start, lblk_end] and returns 3428 * whether there are any buffers marked for delayed allocation. It returns '1' 3429 * on the first delalloc'ed buffer head found. If no buffer head in the given 3430 * range is marked for delalloc, it returns 0. 3431 * lblk_start should always be <= lblk_end. 3432 * search_hint_reverse is to indicate that searching in reverse from lblk_end to 3433 * lblk_start might be more efficient (i.e., we will likely hit the delalloc'ed 3434 * block sooner). This is useful when blocks are truncated sequentially from 3435 * lblk_start towards lblk_end. 3436 */ 3437static int ext4_find_delalloc_range(struct inode *inode, 3438 ext4_lblk_t lblk_start, 3439 ext4_lblk_t lblk_end, 3440 int search_hint_reverse) 3441{ 3442 struct address_space *mapping = inode->i_mapping; 3443 struct buffer_head *head, *bh = NULL; 3444 struct page *page; 3445 ext4_lblk_t i, pg_lblk; 3446 pgoff_t index; 3447 3448 if (!test_opt(inode->i_sb, DELALLOC)) 3449 return 0; 3450 3451 /* reverse search wont work if fs block size is less than page size */ 3452 if (inode->i_blkbits < PAGE_CACHE_SHIFT) 3453 search_hint_reverse = 0; 3454 3455 if (search_hint_reverse) 3456 i = lblk_end; 3457 else 3458 i = lblk_start; 3459 3460 index = i >> (PAGE_CACHE_SHIFT - inode->i_blkbits); 3461 3462 while ((i >= lblk_start) && (i <= lblk_end)) { 3463 page = find_get_page(mapping, index); 3464 if (!page) 3465 goto nextpage; 3466 3467 if (!page_has_buffers(page)) 3468 goto nextpage; 3469 3470 head = page_buffers(page); 3471 if (!head) 3472 goto nextpage; 3473 3474 bh = head; 3475 pg_lblk = index << (PAGE_CACHE_SHIFT - 3476 inode->i_blkbits); 3477 do { 3478 if (unlikely(pg_lblk < lblk_start)) { 3479 /* 3480 * This is possible when fs block size is less 3481 * than page size and our cluster starts/ends in 3482 * middle of the page. So we need to skip the 3483 * initial few blocks till we reach the 'lblk' 3484 */ 3485 pg_lblk++; 3486 continue; 3487 } 3488 3489 /* Check if the buffer is delayed allocated and that it 3490 * is not yet mapped. (when da-buffers are mapped during 3491 * their writeout, their da_mapped bit is set.) 3492 */ 3493 if (buffer_delay(bh) && !buffer_da_mapped(bh)) { 3494 page_cache_release(page); 3495 trace_ext4_find_delalloc_range(inode, 3496 lblk_start, lblk_end, 3497 search_hint_reverse, 3498 1, i); 3499 return 1; 3500 } 3501 if (search_hint_reverse) 3502 i--; 3503 else 3504 i++; 3505 } while ((i >= lblk_start) && (i <= lblk_end) && 3506 ((bh = bh->b_this_page) != head)); 3507nextpage: 3508 if (page) 3509 page_cache_release(page); 3510 /* 3511 * Move to next page. 'i' will be the first lblk in the next 3512 * page. 3513 */ 3514 if (search_hint_reverse) 3515 index--; 3516 else 3517 index++; 3518 i = index << (PAGE_CACHE_SHIFT - inode->i_blkbits); 3519 } 3520 3521 trace_ext4_find_delalloc_range(inode, lblk_start, lblk_end, 3522 search_hint_reverse, 0, 0); 3523 return 0; 3524} 3525 3526int ext4_find_delalloc_cluster(struct inode *inode, ext4_lblk_t lblk, 3527 int search_hint_reverse) 3528{ 3529 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 3530 ext4_lblk_t lblk_start, lblk_end; 3531 lblk_start = lblk & (~(sbi->s_cluster_ratio - 1)); 3532 lblk_end = lblk_start + sbi->s_cluster_ratio - 1; 3533 3534 return ext4_find_delalloc_range(inode, lblk_start, lblk_end, 3535 search_hint_reverse); 3536} 3537 3538/** 3539 * Determines how many complete clusters (out of those specified by the 'map') 3540 * are under delalloc and were reserved quota for. 3541 * This function is called when we are writing out the blocks that were 3542 * originally written with their allocation delayed, but then the space was 3543 * allocated using fallocate() before the delayed allocation could be resolved. 3544 * The cases to look for are: 3545 * ('=' indicated delayed allocated blocks 3546 * '-' indicates non-delayed allocated blocks) 3547 * (a) partial clusters towards beginning and/or end outside of allocated range 3548 * are not delalloc'ed. 3549 * Ex: 3550 * |----c---=|====c====|====c====|===-c----| 3551 * |++++++ allocated ++++++| 3552 * ==> 4 complete clusters in above example 3553 * 3554 * (b) partial cluster (outside of allocated range) towards either end is 3555 * marked for delayed allocation. In this case, we will exclude that 3556 * cluster. 3557 * Ex: 3558 * |----====c========|========c========| 3559 * |++++++ allocated ++++++| 3560 * ==> 1 complete clusters in above example 3561 * 3562 * Ex: 3563 * |================c================| 3564 * |++++++ allocated ++++++| 3565 * ==> 0 complete clusters in above example 3566 * 3567 * The ext4_da_update_reserve_space will be called only if we 3568 * determine here that there were some "entire" clusters that span 3569 * this 'allocated' range. 3570 * In the non-bigalloc case, this function will just end up returning num_blks 3571 * without ever calling ext4_find_delalloc_range. 3572 */ 3573static unsigned int 3574get_reserved_cluster_alloc(struct inode *inode, ext4_lblk_t lblk_start, 3575 unsigned int num_blks) 3576{ 3577 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 3578 ext4_lblk_t alloc_cluster_start, alloc_cluster_end; 3579 ext4_lblk_t lblk_from, lblk_to, c_offset; 3580 unsigned int allocated_clusters = 0; 3581 3582 alloc_cluster_start = EXT4_B2C(sbi, lblk_start); 3583 alloc_cluster_end = EXT4_B2C(sbi, lblk_start + num_blks - 1); 3584 3585 /* max possible clusters for this allocation */ 3586 allocated_clusters = alloc_cluster_end - alloc_cluster_start + 1; 3587 3588 trace_ext4_get_reserved_cluster_alloc(inode, lblk_start, num_blks); 3589 3590 /* Check towards left side */ 3591 c_offset = lblk_start & (sbi->s_cluster_ratio - 1); 3592 if (c_offset) { 3593 lblk_from = lblk_start & (~(sbi->s_cluster_ratio - 1)); 3594 lblk_to = lblk_from + c_offset - 1; 3595 3596 if (ext4_find_delalloc_range(inode, lblk_from, lblk_to, 0)) 3597 allocated_clusters--; 3598 } 3599 3600 /* Now check towards right. */ 3601 c_offset = (lblk_start + num_blks) & (sbi->s_cluster_ratio - 1); 3602 if (allocated_clusters && c_offset) { 3603 lblk_from = lblk_start + num_blks; 3604 lblk_to = lblk_from + (sbi->s_cluster_ratio - c_offset) - 1; 3605 3606 if (ext4_find_delalloc_range(inode, lblk_from, lblk_to, 0)) 3607 allocated_clusters--; 3608 } 3609 3610 return allocated_clusters; 3611} 3612 3613static int 3614ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode, 3615 struct ext4_map_blocks *map, 3616 struct ext4_ext_path *path, int flags, 3617 unsigned int allocated, ext4_fsblk_t newblock) 3618{ 3619 int ret = 0; 3620 int err = 0; 3621 ext4_io_end_t *io = EXT4_I(inode)->cur_aio_dio; 3622 3623 ext_debug("ext4_ext_handle_uninitialized_extents: inode %lu, logical " 3624 "block %llu, max_blocks %u, flags %x, allocated %u\n", 3625 inode->i_ino, (unsigned long long)map->m_lblk, map->m_len, 3626 flags, allocated); 3627 ext4_ext_show_leaf(inode, path); 3628 3629 trace_ext4_ext_handle_uninitialized_extents(inode, map, allocated, 3630 newblock); 3631 3632 /* get_block() before submit the IO, split the extent */ 3633 if ((flags & EXT4_GET_BLOCKS_PRE_IO)) { 3634 ret = ext4_split_unwritten_extents(handle, inode, map, 3635 path, flags); 3636 /* 3637 * Flag the inode(non aio case) or end_io struct (aio case) 3638 * that this IO needs to conversion to written when IO is 3639 * completed 3640 */ 3641 if (io) 3642 ext4_set_io_unwritten_flag(inode, io); 3643 else 3644 ext4_set_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN); 3645 if (ext4_should_dioread_nolock(inode)) 3646 map->m_flags |= EXT4_MAP_UNINIT; 3647 goto out; 3648 } 3649 /* IO end_io complete, convert the filled extent to written */ 3650 if ((flags & EXT4_GET_BLOCKS_CONVERT)) { 3651 ret = ext4_convert_unwritten_extents_endio(handle, inode, 3652 path); 3653 if (ret >= 0) { 3654 ext4_update_inode_fsync_trans(handle, inode, 1); 3655 err = check_eofblocks_fl(handle, inode, map->m_lblk, 3656 path, map->m_len); 3657 } else 3658 err = ret; 3659 goto out2; 3660 } 3661 /* buffered IO case */ 3662 /* 3663 * repeat fallocate creation request 3664 * we already have an unwritten extent 3665 */ 3666 if (flags & EXT4_GET_BLOCKS_UNINIT_EXT) 3667 goto map_out; 3668 3669 /* buffered READ or buffered write_begin() lookup */ 3670 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) { 3671 /* 3672 * We have blocks reserved already. We 3673 * return allocated blocks so that delalloc 3674 * won't do block reservation for us. But 3675 * the buffer head will be unmapped so that 3676 * a read from the block returns 0s. 3677 */ 3678 map->m_flags |= EXT4_MAP_UNWRITTEN; 3679 goto out1; 3680 } 3681 3682 /* buffered write, writepage time, convert*/ 3683 ret = ext4_ext_convert_to_initialized(handle, inode, map, path); 3684 if (ret >= 0) 3685 ext4_update_inode_fsync_trans(handle, inode, 1); 3686out: 3687 if (ret <= 0) { 3688 err = ret; 3689 goto out2; 3690 } else 3691 allocated = ret; 3692 map->m_flags |= EXT4_MAP_NEW; 3693 /* 3694 * if we allocated more blocks than requested 3695 * we need to make sure we unmap the extra block 3696 * allocated. The actual needed block will get 3697 * unmapped later when we find the buffer_head marked 3698 * new. 3699 */ 3700 if (allocated > map->m_len) { 3701 unmap_underlying_metadata_blocks(inode->i_sb->s_bdev, 3702 newblock + map->m_len, 3703 allocated - map->m_len); 3704 allocated = map->m_len; 3705 } 3706 3707 /* 3708 * If we have done fallocate with the offset that is already 3709 * delayed allocated, we would have block reservation 3710 * and quota reservation done in the delayed write path. 3711 * But fallocate would have already updated quota and block 3712 * count for this offset. So cancel these reservation 3713 */ 3714 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) { 3715 unsigned int reserved_clusters; 3716 reserved_clusters = get_reserved_cluster_alloc(inode, 3717 map->m_lblk, map->m_len); 3718 if (reserved_clusters) 3719 ext4_da_update_reserve_space(inode, 3720 reserved_clusters, 3721 0); 3722 } 3723 3724map_out: 3725 map->m_flags |= EXT4_MAP_MAPPED; 3726 if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0) { 3727 err = check_eofblocks_fl(handle, inode, map->m_lblk, path, 3728 map->m_len); 3729 if (err < 0) 3730 goto out2; 3731 } 3732out1: 3733 if (allocated > map->m_len) 3734 allocated = map->m_len; 3735 ext4_ext_show_leaf(inode, path); 3736 map->m_pblk = newblock; 3737 map->m_len = allocated; 3738out2: 3739 if (path) { 3740 ext4_ext_drop_refs(path); 3741 kfree(path); 3742 } 3743 return err ? err : allocated; 3744} 3745 3746/* 3747 * get_implied_cluster_alloc - check to see if the requested 3748 * allocation (in the map structure) overlaps with a cluster already 3749 * allocated in an extent. 3750 * @sb The filesystem superblock structure 3751 * @map The requested lblk->pblk mapping 3752 * @ex The extent structure which might contain an implied 3753 * cluster allocation 3754 * 3755 * This function is called by ext4_ext_map_blocks() after we failed to 3756 * find blocks that were already in the inode's extent tree. Hence, 3757 * we know that the beginning of the requested region cannot overlap 3758 * the extent from the inode's extent tree. There are three cases we 3759 * want to catch. The first is this case: 3760 * 3761 * |--- cluster # N--| 3762 * |--- extent ---| |---- requested region ---| 3763 * |==========| 3764 * 3765 * The second case that we need to test for is this one: 3766 * 3767 * |--------- cluster # N ----------------| 3768 * |--- requested region --| |------- extent ----| 3769 * |=======================| 3770 * 3771 * The third case is when the requested region lies between two extents 3772 * within the same cluster: 3773 * |------------- cluster # N-------------| 3774 * |----- ex -----| |---- ex_right ----| 3775 * |------ requested region ------| 3776 * |================| 3777 * 3778 * In each of the above cases, we need to set the map->m_pblk and 3779 * map->m_len so it corresponds to the return the extent labelled as 3780 * "|====|" from cluster #N, since it is already in use for data in 3781 * cluster EXT4_B2C(sbi, map->m_lblk). We will then return 1 to 3782 * signal to ext4_ext_map_blocks() that map->m_pblk should be treated 3783 * as a new "allocated" block region. Otherwise, we will return 0 and 3784 * ext4_ext_map_blocks() will then allocate one or more new clusters 3785 * by calling ext4_mb_new_blocks(). 3786 */ 3787static int get_implied_cluster_alloc(struct super_block *sb, 3788 struct ext4_map_blocks *map, 3789 struct ext4_extent *ex, 3790 struct ext4_ext_path *path) 3791{ 3792 struct ext4_sb_info *sbi = EXT4_SB(sb); 3793 ext4_lblk_t c_offset = map->m_lblk & (sbi->s_cluster_ratio-1); 3794 ext4_lblk_t ex_cluster_start, ex_cluster_end; 3795 ext4_lblk_t rr_cluster_start; 3796 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block); 3797 ext4_fsblk_t ee_start = ext4_ext_pblock(ex); 3798 unsigned short ee_len = ext4_ext_get_actual_len(ex); 3799 3800 /* The extent passed in that we are trying to match */ 3801 ex_cluster_start = EXT4_B2C(sbi, ee_block); 3802 ex_cluster_end = EXT4_B2C(sbi, ee_block + ee_len - 1); 3803 3804 /* The requested region passed into ext4_map_blocks() */ 3805 rr_cluster_start = EXT4_B2C(sbi, map->m_lblk); 3806 3807 if ((rr_cluster_start == ex_cluster_end) || 3808 (rr_cluster_start == ex_cluster_start)) { 3809 if (rr_cluster_start == ex_cluster_end) 3810 ee_start += ee_len - 1; 3811 map->m_pblk = (ee_start & ~(sbi->s_cluster_ratio - 1)) + 3812 c_offset; 3813 map->m_len = min(map->m_len, 3814 (unsigned) sbi->s_cluster_ratio - c_offset); 3815 /* 3816 * Check for and handle this case: 3817 * 3818 * |--------- cluster # N-------------| 3819 * |------- extent ----| 3820 * |--- requested region ---| 3821 * |===========| 3822 */ 3823 3824 if (map->m_lblk < ee_block) 3825 map->m_len = min(map->m_len, ee_block - map->m_lblk); 3826 3827 /* 3828 * Check for the case where there is already another allocated 3829 * block to the right of 'ex' but before the end of the cluster. 3830 * 3831 * |------------- cluster # N-------------| 3832 * |----- ex -----| |---- ex_right ----| 3833 * |------ requested region ------| 3834 * |================| 3835 */ 3836 if (map->m_lblk > ee_block) { 3837 ext4_lblk_t next = ext4_ext_next_allocated_block(path); 3838 map->m_len = min(map->m_len, next - map->m_lblk); 3839 } 3840 3841 trace_ext4_get_implied_cluster_alloc_exit(sb, map, 1); 3842 return 1; 3843 } 3844 3845 trace_ext4_get_implied_cluster_alloc_exit(sb, map, 0); 3846 return 0; 3847} 3848 3849 3850/* 3851 * Block allocation/map/preallocation routine for extents based files 3852 * 3853 * 3854 * Need to be called with 3855 * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block 3856 * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem) 3857 * 3858 * return > 0, number of of blocks already mapped/allocated 3859 * if create == 0 and these are pre-allocated blocks 3860 * buffer head is unmapped 3861 * otherwise blocks are mapped 3862 * 3863 * return = 0, if plain look up failed (blocks have not been allocated) 3864 * buffer head is unmapped 3865 * 3866 * return < 0, error case. 3867 */ 3868int ext4_ext_map_blocks(handle_t *handle, struct inode *inode, 3869 struct ext4_map_blocks *map, int flags) 3870{ 3871 struct ext4_ext_path *path = NULL; 3872 struct ext4_extent newex, *ex, *ex2; 3873 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 3874 ext4_fsblk_t newblock = 0; 3875 int free_on_err = 0, err = 0, depth, ret; 3876 unsigned int allocated = 0, offset = 0; 3877 unsigned int allocated_clusters = 0; 3878 struct ext4_allocation_request ar; 3879 ext4_io_end_t *io = EXT4_I(inode)->cur_aio_dio; 3880 ext4_lblk_t cluster_offset; 3881 3882 ext_debug("blocks %u/%u requested for inode %lu\n", 3883 map->m_lblk, map->m_len, inode->i_ino); 3884 trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags); 3885 3886 /* check in cache */ 3887 if (ext4_ext_in_cache(inode, map->m_lblk, &newex)) { 3888 if (!newex.ee_start_lo && !newex.ee_start_hi) { 3889 if ((sbi->s_cluster_ratio > 1) && 3890 ext4_find_delalloc_cluster(inode, map->m_lblk, 0)) 3891 map->m_flags |= EXT4_MAP_FROM_CLUSTER; 3892 3893 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) { 3894 /* 3895 * block isn't allocated yet and 3896 * user doesn't want to allocate it 3897 */ 3898 goto out2; 3899 } 3900 /* we should allocate requested block */ 3901 } else { 3902 /* block is already allocated */ 3903 if (sbi->s_cluster_ratio > 1) 3904 map->m_flags |= EXT4_MAP_FROM_CLUSTER; 3905 newblock = map->m_lblk 3906 - le32_to_cpu(newex.ee_block) 3907 + ext4_ext_pblock(&newex); 3908 /* number of remaining blocks in the extent */ 3909 allocated = ext4_ext_get_actual_len(&newex) - 3910 (map->m_lblk - le32_to_cpu(newex.ee_block)); 3911 goto out; 3912 } 3913 } 3914 3915 /* find extent for this block */ 3916 path = ext4_ext_find_extent(inode, map->m_lblk, NULL); 3917 if (IS_ERR(path)) { 3918 err = PTR_ERR(path); 3919 path = NULL; 3920 goto out2; 3921 } 3922 3923 depth = ext_depth(inode); 3924 3925 /* 3926 * consistent leaf must not be empty; 3927 * this situation is possible, though, _during_ tree modification; 3928 * this is why assert can't be put in ext4_ext_find_extent() 3929 */ 3930 if (unlikely(path[depth].p_ext == NULL && depth != 0)) { 3931 EXT4_ERROR_INODE(inode, "bad extent address " 3932 "lblock: %lu, depth: %d pblock %lld", 3933 (unsigned long) map->m_lblk, depth, 3934 path[depth].p_block); 3935 err = -EIO; 3936 goto out2; 3937 } 3938 3939 ex = path[depth].p_ext; 3940 if (ex) { 3941 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block); 3942 ext4_fsblk_t ee_start = ext4_ext_pblock(ex); 3943 unsigned short ee_len; 3944 3945 /* 3946 * Uninitialized extents are treated as holes, except that 3947 * we split out initialized portions during a write. 3948 */ 3949 ee_len = ext4_ext_get_actual_len(ex); 3950 3951 trace_ext4_ext_show_extent(inode, ee_block, ee_start, ee_len); 3952 3953 /* if found extent covers block, simply return it */ 3954 if (in_range(map->m_lblk, ee_block, ee_len)) { 3955 newblock = map->m_lblk - ee_block + ee_start; 3956 /* number of remaining blocks in the extent */ 3957 allocated = ee_len - (map->m_lblk - ee_block); 3958 ext_debug("%u fit into %u:%d -> %llu\n", map->m_lblk, 3959 ee_block, ee_len, newblock); 3960 3961 /* 3962 * Do not put uninitialized extent 3963 * in the cache 3964 */ 3965 if (!ext4_ext_is_uninitialized(ex)) { 3966 ext4_ext_put_in_cache(inode, ee_block, 3967 ee_len, ee_start); 3968 goto out; 3969 } 3970 ret = ext4_ext_handle_uninitialized_extents( 3971 handle, inode, map, path, flags, 3972 allocated, newblock); 3973 return ret; 3974 } 3975 } 3976 3977 if ((sbi->s_cluster_ratio > 1) && 3978 ext4_find_delalloc_cluster(inode, map->m_lblk, 0)) 3979 map->m_flags |= EXT4_MAP_FROM_CLUSTER; 3980 3981 /* 3982 * requested block isn't allocated yet; 3983 * we couldn't try to create block if create flag is zero 3984 */ 3985 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) { 3986 /* 3987 * put just found gap into cache to speed up 3988 * subsequent requests 3989 */ 3990 ext4_ext_put_gap_in_cache(inode, path, map->m_lblk); 3991 goto out2; 3992 } 3993 3994 /* 3995 * Okay, we need to do block allocation. 3996 */ 3997 map->m_flags &= ~EXT4_MAP_FROM_CLUSTER; 3998 newex.ee_block = cpu_to_le32(map->m_lblk); 3999 cluster_offset = map->m_lblk & (sbi->s_cluster_ratio-1); 4000 4001 /* 4002 * If we are doing bigalloc, check to see if the extent returned 4003 * by ext4_ext_find_extent() implies a cluster we can use. 4004 */ 4005 if (cluster_offset && ex && 4006 get_implied_cluster_alloc(inode->i_sb, map, ex, path)) { 4007 ar.len = allocated = map->m_len; 4008 newblock = map->m_pblk; 4009 map->m_flags |= EXT4_MAP_FROM_CLUSTER; 4010 goto got_allocated_blocks; 4011 } 4012 4013 /* find neighbour allocated blocks */ 4014 ar.lleft = map->m_lblk; 4015 err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft); 4016 if (err) 4017 goto out2; 4018 ar.lright = map->m_lblk; 4019 ex2 = NULL; 4020 err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright, &ex2); 4021 if (err) 4022 goto out2; 4023 4024 /* Check if the extent after searching to the right implies a 4025 * cluster we can use. */ 4026 if ((sbi->s_cluster_ratio > 1) && ex2 && 4027 get_implied_cluster_alloc(inode->i_sb, map, ex2, path)) { 4028 ar.len = allocated = map->m_len; 4029 newblock = map->m_pblk; 4030 map->m_flags |= EXT4_MAP_FROM_CLUSTER; 4031 goto got_allocated_blocks; 4032 } 4033 4034 /* 4035 * See if request is beyond maximum number of blocks we can have in 4036 * a single extent. For an initialized extent this limit is 4037 * EXT_INIT_MAX_LEN and for an uninitialized extent this limit is 4038 * EXT_UNINIT_MAX_LEN. 4039 */ 4040 if (map->m_len > EXT_INIT_MAX_LEN && 4041 !(flags & EXT4_GET_BLOCKS_UNINIT_EXT)) 4042 map->m_len = EXT_INIT_MAX_LEN; 4043 else if (map->m_len > EXT_UNINIT_MAX_LEN && 4044 (flags & EXT4_GET_BLOCKS_UNINIT_EXT)) 4045 map->m_len = EXT_UNINIT_MAX_LEN; 4046 4047 /* Check if we can really insert (m_lblk)::(m_lblk + m_len) extent */ 4048 newex.ee_len = cpu_to_le16(map->m_len); 4049 err = ext4_ext_check_overlap(sbi, inode, &newex, path); 4050 if (err) 4051 allocated = ext4_ext_get_actual_len(&newex); 4052 else 4053 allocated = map->m_len; 4054 4055 /* allocate new block */ 4056 ar.inode = inode; 4057 ar.goal = ext4_ext_find_goal(inode, path, map->m_lblk); 4058 ar.logical = map->m_lblk; 4059 /* 4060 * We calculate the offset from the beginning of the cluster 4061 * for the logical block number, since when we allocate a 4062 * physical cluster, the physical block should start at the 4063 * same offset from the beginning of the cluster. This is 4064 * needed so that future calls to get_implied_cluster_alloc() 4065 * work correctly. 4066 */ 4067 offset = map->m_lblk & (sbi->s_cluster_ratio - 1); 4068 ar.len = EXT4_NUM_B2C(sbi, offset+allocated); 4069 ar.goal -= offset; 4070 ar.logical -= offset; 4071 if (S_ISREG(inode->i_mode)) 4072 ar.flags = EXT4_MB_HINT_DATA; 4073 else 4074 /* disable in-core preallocation for non-regular files */ 4075 ar.flags = 0; 4076 if (flags & EXT4_GET_BLOCKS_NO_NORMALIZE) 4077 ar.flags |= EXT4_MB_HINT_NOPREALLOC; 4078 newblock = ext4_mb_new_blocks(handle, &ar, &err); 4079 if (!newblock) 4080 goto out2; 4081 ext_debug("allocate new block: goal %llu, found %llu/%u\n", 4082 ar.goal, newblock, allocated); 4083 free_on_err = 1; 4084 allocated_clusters = ar.len; 4085 ar.len = EXT4_C2B(sbi, ar.len) - offset; 4086 if (ar.len > allocated) 4087 ar.len = allocated; 4088 4089got_allocated_blocks: 4090 /* try to insert new extent into found leaf and return */ 4091 ext4_ext_store_pblock(&newex, newblock + offset); 4092 newex.ee_len = cpu_to_le16(ar.len); 4093 /* Mark uninitialized */ 4094 if (flags & EXT4_GET_BLOCKS_UNINIT_EXT){ 4095 ext4_ext_mark_uninitialized(&newex); 4096 /* 4097 * io_end structure was created for every IO write to an 4098 * uninitialized extent. To avoid unnecessary conversion, 4099 * here we flag the IO that really needs the conversion. 4100 * For non asycn direct IO case, flag the inode state 4101 * that we need to perform conversion when IO is done. 4102 */ 4103 if ((flags & EXT4_GET_BLOCKS_PRE_IO)) { 4104 if (io) 4105 ext4_set_io_unwritten_flag(inode, io); 4106 else 4107 ext4_set_inode_state(inode, 4108 EXT4_STATE_DIO_UNWRITTEN); 4109 } 4110 if (ext4_should_dioread_nolock(inode)) 4111 map->m_flags |= EXT4_MAP_UNINIT; 4112 } 4113 4114 err = 0; 4115 if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0) 4116 err = check_eofblocks_fl(handle, inode, map->m_lblk, 4117 path, ar.len); 4118 if (!err) 4119 err = ext4_ext_insert_extent(handle, inode, path, 4120 &newex, flags); 4121 if (err && free_on_err) { 4122 int fb_flags = flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE ? 4123 EXT4_FREE_BLOCKS_NO_QUOT_UPDATE : 0; 4124 /* free data blocks we just allocated */ 4125 /* not a good idea to call discard here directly, 4126 * but otherwise we'd need to call it every free() */ 4127 ext4_discard_preallocations(inode); 4128 ext4_free_blocks(handle, inode, NULL, ext4_ext_pblock(&newex), 4129 ext4_ext_get_actual_len(&newex), fb_flags); 4130 goto out2; 4131 } 4132 4133 /* previous routine could use block we allocated */ 4134 newblock = ext4_ext_pblock(&newex); 4135 allocated = ext4_ext_get_actual_len(&newex); 4136 if (allocated > map->m_len) 4137 allocated = map->m_len; 4138 map->m_flags |= EXT4_MAP_NEW; 4139 4140 /* 4141 * Update reserved blocks/metadata blocks after successful 4142 * block allocation which had been deferred till now. 4143 */ 4144 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) { 4145 unsigned int reserved_clusters; 4146 /* 4147 * Check how many clusters we had reserved this allocated range 4148 */ 4149 reserved_clusters = get_reserved_cluster_alloc(inode, 4150 map->m_lblk, allocated); 4151 if (map->m_flags & EXT4_MAP_FROM_CLUSTER) { 4152 if (reserved_clusters) { 4153 /* 4154 * We have clusters reserved for this range. 4155 * But since we are not doing actual allocation 4156 * and are simply using blocks from previously 4157 * allocated cluster, we should release the 4158 * reservation and not claim quota. 4159 */ 4160 ext4_da_update_reserve_space(inode, 4161 reserved_clusters, 0); 4162 } 4163 } else { 4164 BUG_ON(allocated_clusters < reserved_clusters); 4165 /* We will claim quota for all newly allocated blocks.*/ 4166 ext4_da_update_reserve_space(inode, allocated_clusters, 4167 1); 4168 if (reserved_clusters < allocated_clusters) { 4169 struct ext4_inode_info *ei = EXT4_I(inode); 4170 int reservation = allocated_clusters - 4171 reserved_clusters; 4172 /* 4173 * It seems we claimed few clusters outside of 4174 * the range of this allocation. We should give 4175 * it back to the reservation pool. This can 4176 * happen in the following case: 4177 * 4178 * * Suppose s_cluster_ratio is 4 (i.e., each 4179 * cluster has 4 blocks. Thus, the clusters 4180 * are [0-3],[4-7],[8-11]... 4181 * * First comes delayed allocation write for 4182 * logical blocks 10 & 11. Since there were no 4183 * previous delayed allocated blocks in the 4184 * range [8-11], we would reserve 1 cluster 4185 * for this write. 4186 * * Next comes write for logical blocks 3 to 8. 4187 * In this case, we will reserve 2 clusters 4188 * (for [0-3] and [4-7]; and not for [8-11] as 4189 * that range has a delayed allocated blocks. 4190 * Thus total reserved clusters now becomes 3. 4191 * * Now, during the delayed allocation writeout 4192 * time, we will first write blocks [3-8] and 4193 * allocate 3 clusters for writing these 4194 * blocks. Also, we would claim all these 4195 * three clusters above. 4196 * * Now when we come here to writeout the 4197 * blocks [10-11], we would expect to claim 4198 * the reservation of 1 cluster we had made 4199 * (and we would claim it since there are no 4200 * more delayed allocated blocks in the range 4201 * [8-11]. But our reserved cluster count had 4202 * already gone to 0. 4203 * 4204 * Thus, at the step 4 above when we determine 4205 * that there are still some unwritten delayed 4206 * allocated blocks outside of our current 4207 * block range, we should increment the 4208 * reserved clusters count so that when the 4209 * remaining blocks finally gets written, we 4210 * could claim them. 4211 */ 4212 dquot_reserve_block(inode, 4213 EXT4_C2B(sbi, reservation)); 4214 spin_lock(&ei->i_block_reservation_lock); 4215 ei->i_reserved_data_blocks += reservation; 4216 spin_unlock(&ei->i_block_reservation_lock); 4217 } 4218 } 4219 } 4220 4221 /* 4222 * Cache the extent and update transaction to commit on fdatasync only 4223 * when it is _not_ an uninitialized extent. 4224 */ 4225 if ((flags & EXT4_GET_BLOCKS_UNINIT_EXT) == 0) { 4226 ext4_ext_put_in_cache(inode, map->m_lblk, allocated, newblock); 4227 ext4_update_inode_fsync_trans(handle, inode, 1); 4228 } else 4229 ext4_update_inode_fsync_trans(handle, inode, 0); 4230out: 4231 if (allocated > map->m_len) 4232 allocated = map->m_len; 4233 ext4_ext_show_leaf(inode, path); 4234 map->m_flags |= EXT4_MAP_MAPPED; 4235 map->m_pblk = newblock; 4236 map->m_len = allocated; 4237out2: 4238 if (path) { 4239 ext4_ext_drop_refs(path); 4240 kfree(path); 4241 } 4242 4243 trace_ext4_ext_map_blocks_exit(inode, map->m_lblk, 4244 newblock, map->m_len, err ? err : allocated); 4245 4246 return err ? err : allocated; 4247} 4248 4249void ext4_ext_truncate(struct inode *inode) 4250{ 4251 struct address_space *mapping = inode->i_mapping; 4252 struct super_block *sb = inode->i_sb; 4253 ext4_lblk_t last_block; 4254 handle_t *handle; 4255 loff_t page_len; 4256 int err = 0; 4257 4258 /* 4259 * finish any pending end_io work so we won't run the risk of 4260 * converting any truncated blocks to initialized later 4261 */ 4262 ext4_flush_completed_IO(inode); 4263 4264 /* 4265 * probably first extent we're gonna free will be last in block 4266 */ 4267 err = ext4_writepage_trans_blocks(inode); 4268 handle = ext4_journal_start(inode, err); 4269 if (IS_ERR(handle)) 4270 return; 4271 4272 if (inode->i_size % PAGE_CACHE_SIZE != 0) { 4273 page_len = PAGE_CACHE_SIZE - 4274 (inode->i_size & (PAGE_CACHE_SIZE - 1)); 4275 4276 err = ext4_discard_partial_page_buffers(handle, 4277 mapping, inode->i_size, page_len, 0); 4278 4279 if (err) 4280 goto out_stop; 4281 } 4282 4283 if (ext4_orphan_add(handle, inode)) 4284 goto out_stop; 4285 4286 down_write(&EXT4_I(inode)->i_data_sem); 4287 ext4_ext_invalidate_cache(inode); 4288 4289 ext4_discard_preallocations(inode); 4290 4291 /* 4292 * TODO: optimization is possible here. 4293 * Probably we need not scan at all, 4294 * because page truncation is enough. 4295 */ 4296 4297 /* we have to know where to truncate from in crash case */ 4298 EXT4_I(inode)->i_disksize = inode->i_size; 4299 ext4_mark_inode_dirty(handle, inode); 4300 4301 last_block = (inode->i_size + sb->s_blocksize - 1) 4302 >> EXT4_BLOCK_SIZE_BITS(sb); 4303 err = ext4_ext_remove_space(inode, last_block, EXT_MAX_BLOCKS - 1); 4304 4305 /* In a multi-transaction truncate, we only make the final 4306 * transaction synchronous. 4307 */ 4308 if (IS_SYNC(inode)) 4309 ext4_handle_sync(handle); 4310 4311 up_write(&EXT4_I(inode)->i_data_sem); 4312 4313out_stop: 4314 /* 4315 * If this was a simple ftruncate() and the file will remain alive, 4316 * then we need to clear up the orphan record which we created above. 4317 * However, if this was a real unlink then we were called by 4318 * ext4_delete_inode(), and we allow that function to clean up the 4319 * orphan info for us. 4320 */ 4321 if (inode->i_nlink) 4322 ext4_orphan_del(handle, inode); 4323 4324 inode->i_mtime = inode->i_ctime = ext4_current_time(inode); 4325 ext4_mark_inode_dirty(handle, inode); 4326 ext4_journal_stop(handle); 4327} 4328 4329static void ext4_falloc_update_inode(struct inode *inode, 4330 int mode, loff_t new_size, int update_ctime) 4331{ 4332 struct timespec now; 4333 4334 if (update_ctime) { 4335 now = current_fs_time(inode->i_sb); 4336 if (!timespec_equal(&inode->i_ctime, &now)) 4337 inode->i_ctime = now; 4338 } 4339 /* 4340 * Update only when preallocation was requested beyond 4341 * the file size. 4342 */ 4343 if (!(mode & FALLOC_FL_KEEP_SIZE)) { 4344 if (new_size > i_size_read(inode)) 4345 i_size_write(inode, new_size); 4346 if (new_size > EXT4_I(inode)->i_disksize) 4347 ext4_update_i_disksize(inode, new_size); 4348 } else { 4349 /* 4350 * Mark that we allocate beyond EOF so the subsequent truncate 4351 * can proceed even if the new size is the same as i_size. 4352 */ 4353 if (new_size > i_size_read(inode)) 4354 ext4_set_inode_flag(inode, EXT4_INODE_EOFBLOCKS); 4355 } 4356 4357} 4358 4359/* 4360 * preallocate space for a file. This implements ext4's fallocate file 4361 * operation, which gets called from sys_fallocate system call. 4362 * For block-mapped files, posix_fallocate should fall back to the method 4363 * of writing zeroes to the required new blocks (the same behavior which is 4364 * expected for file systems which do not support fallocate() system call). 4365 */ 4366long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len) 4367{ 4368 struct inode *inode = file->f_path.dentry->d_inode; 4369 handle_t *handle; 4370 loff_t new_size; 4371 unsigned int max_blocks; 4372 int ret = 0; 4373 int ret2 = 0; 4374 int retries = 0; 4375 int flags; 4376 struct ext4_map_blocks map; 4377 unsigned int credits, blkbits = inode->i_blkbits; 4378 4379 /* 4380 * currently supporting (pre)allocate mode for extent-based 4381 * files _only_ 4382 */ 4383 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) 4384 return -EOPNOTSUPP; 4385 4386 /* Return error if mode is not supported */ 4387 if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE)) 4388 return -EOPNOTSUPP; 4389 4390 if (mode & FALLOC_FL_PUNCH_HOLE) 4391 return ext4_punch_hole(file, offset, len); 4392 4393 trace_ext4_fallocate_enter(inode, offset, len, mode); 4394 map.m_lblk = offset >> blkbits; 4395 /* 4396 * We can't just convert len to max_blocks because 4397 * If blocksize = 4096 offset = 3072 and len = 2048 4398 */ 4399 max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits) 4400 - map.m_lblk; 4401 /* 4402 * credits to insert 1 extent into extent tree 4403 */ 4404 credits = ext4_chunk_trans_blocks(inode, max_blocks); 4405 mutex_lock(&inode->i_mutex); 4406 ret = inode_newsize_ok(inode, (len + offset)); 4407 if (ret) { 4408 mutex_unlock(&inode->i_mutex); 4409 trace_ext4_fallocate_exit(inode, offset, max_blocks, ret); 4410 return ret; 4411 } 4412 flags = EXT4_GET_BLOCKS_CREATE_UNINIT_EXT; 4413 if (mode & FALLOC_FL_KEEP_SIZE) 4414 flags |= EXT4_GET_BLOCKS_KEEP_SIZE; 4415 /* 4416 * Don't normalize the request if it can fit in one extent so 4417 * that it doesn't get unnecessarily split into multiple 4418 * extents. 4419 */ 4420 if (len <= EXT_UNINIT_MAX_LEN << blkbits) 4421 flags |= EXT4_GET_BLOCKS_NO_NORMALIZE; 4422retry: 4423 while (ret >= 0 && ret < max_blocks) { 4424 map.m_lblk = map.m_lblk + ret; 4425 map.m_len = max_blocks = max_blocks - ret; 4426 handle = ext4_journal_start(inode, credits); 4427 if (IS_ERR(handle)) { 4428 ret = PTR_ERR(handle); 4429 break; 4430 } 4431 ret = ext4_map_blocks(handle, inode, &map, flags); 4432 if (ret <= 0) { 4433#ifdef EXT4FS_DEBUG 4434 WARN_ON(ret <= 0); 4435 printk(KERN_ERR "%s: ext4_ext_map_blocks " 4436 "returned error inode#%lu, block=%u, " 4437 "max_blocks=%u", __func__, 4438 inode->i_ino, map.m_lblk, max_blocks); 4439#endif 4440 ext4_mark_inode_dirty(handle, inode); 4441 ret2 = ext4_journal_stop(handle); 4442 break; 4443 } 4444 if ((map.m_lblk + ret) >= (EXT4_BLOCK_ALIGN(offset + len, 4445 blkbits) >> blkbits)) 4446 new_size = offset + len; 4447 else 4448 new_size = ((loff_t) map.m_lblk + ret) << blkbits; 4449 4450 ext4_falloc_update_inode(inode, mode, new_size, 4451 (map.m_flags & EXT4_MAP_NEW)); 4452 ext4_mark_inode_dirty(handle, inode); 4453 if ((file->f_flags & O_SYNC) && ret >= max_blocks) 4454 ext4_handle_sync(handle); 4455 ret2 = ext4_journal_stop(handle); 4456 if (ret2) 4457 break; 4458 } 4459 if (ret == -ENOSPC && 4460 ext4_should_retry_alloc(inode->i_sb, &retries)) { 4461 ret = 0; 4462 goto retry; 4463 } 4464 mutex_unlock(&inode->i_mutex); 4465 trace_ext4_fallocate_exit(inode, offset, max_blocks, 4466 ret > 0 ? ret2 : ret); 4467 return ret > 0 ? ret2 : ret; 4468} 4469 4470/* 4471 * This function convert a range of blocks to written extents 4472 * The caller of this function will pass the start offset and the size. 4473 * all unwritten extents within this range will be converted to 4474 * written extents. 4475 * 4476 * This function is called from the direct IO end io call back 4477 * function, to convert the fallocated extents after IO is completed. 4478 * Returns 0 on success. 4479 */ 4480int ext4_convert_unwritten_extents(struct inode *inode, loff_t offset, 4481 ssize_t len) 4482{ 4483 handle_t *handle; 4484 unsigned int max_blocks; 4485 int ret = 0; 4486 int ret2 = 0; 4487 struct ext4_map_blocks map; 4488 unsigned int credits, blkbits = inode->i_blkbits; 4489 4490 map.m_lblk = offset >> blkbits; 4491 /* 4492 * We can't just convert len to max_blocks because 4493 * If blocksize = 4096 offset = 3072 and len = 2048 4494 */ 4495 max_blocks = ((EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits) - 4496 map.m_lblk); 4497 /* 4498 * credits to insert 1 extent into extent tree 4499 */ 4500 credits = ext4_chunk_trans_blocks(inode, max_blocks); 4501 while (ret >= 0 && ret < max_blocks) { 4502 map.m_lblk += ret; 4503 map.m_len = (max_blocks -= ret); 4504 handle = ext4_journal_start(inode, credits); 4505 if (IS_ERR(handle)) { 4506 ret = PTR_ERR(handle); 4507 break; 4508 } 4509 ret = ext4_map_blocks(handle, inode, &map, 4510 EXT4_GET_BLOCKS_IO_CONVERT_EXT); 4511 if (ret <= 0) { 4512 WARN_ON(ret <= 0); 4513 ext4_msg(inode->i_sb, KERN_ERR, 4514 "%s:%d: inode #%lu: block %u: len %u: " 4515 "ext4_ext_map_blocks returned %d", 4516 __func__, __LINE__, inode->i_ino, map.m_lblk, 4517 map.m_len, ret); 4518 } 4519 ext4_mark_inode_dirty(handle, inode); 4520 ret2 = ext4_journal_stop(handle); 4521 if (ret <= 0 || ret2 ) 4522 break; 4523 } 4524 return ret > 0 ? ret2 : ret; 4525} 4526 4527/* 4528 * Callback function called for each extent to gather FIEMAP information. 4529 */ 4530static int ext4_ext_fiemap_cb(struct inode *inode, ext4_lblk_t next, 4531 struct ext4_ext_cache *newex, struct ext4_extent *ex, 4532 void *data) 4533{ 4534 __u64 logical; 4535 __u64 physical; 4536 __u64 length; 4537 __u32 flags = 0; 4538 int ret = 0; 4539 struct fiemap_extent_info *fieinfo = data; 4540 unsigned char blksize_bits; 4541 4542 blksize_bits = inode->i_sb->s_blocksize_bits; 4543 logical = (__u64)newex->ec_block << blksize_bits; 4544 4545 if (newex->ec_start == 0) { 4546 /* 4547 * No extent in extent-tree contains block @newex->ec_start, 4548 * then the block may stay in 1)a hole or 2)delayed-extent. 4549 * 4550 * Holes or delayed-extents are processed as follows. 4551 * 1. lookup dirty pages with specified range in pagecache. 4552 * If no page is got, then there is no delayed-extent and 4553 * return with EXT_CONTINUE. 4554 * 2. find the 1st mapped buffer, 4555 * 3. check if the mapped buffer is both in the request range 4556 * and a delayed buffer. If not, there is no delayed-extent, 4557 * then return. 4558 * 4. a delayed-extent is found, the extent will be collected. 4559 */ 4560 ext4_lblk_t end = 0; 4561 pgoff_t last_offset; 4562 pgoff_t offset; 4563 pgoff_t index; 4564 pgoff_t start_index = 0; 4565 struct page **pages = NULL; 4566 struct buffer_head *bh = NULL; 4567 struct buffer_head *head = NULL; 4568 unsigned int nr_pages = PAGE_SIZE / sizeof(struct page *); 4569 4570 pages = kmalloc(PAGE_SIZE, GFP_KERNEL); 4571 if (pages == NULL) 4572 return -ENOMEM; 4573 4574 offset = logical >> PAGE_SHIFT; 4575repeat: 4576 last_offset = offset; 4577 head = NULL; 4578 ret = find_get_pages_tag(inode->i_mapping, &offset, 4579 PAGECACHE_TAG_DIRTY, nr_pages, pages); 4580 4581 if (!(flags & FIEMAP_EXTENT_DELALLOC)) { 4582 /* First time, try to find a mapped buffer. */ 4583 if (ret == 0) { 4584out: 4585 for (index = 0; index < ret; index++) 4586 page_cache_release(pages[index]); 4587 /* just a hole. */ 4588 kfree(pages); 4589 return EXT_CONTINUE; 4590 } 4591 index = 0; 4592 4593next_page: 4594 /* Try to find the 1st mapped buffer. */ 4595 end = ((__u64)pages[index]->index << PAGE_SHIFT) >> 4596 blksize_bits; 4597 if (!page_has_buffers(pages[index])) 4598 goto out; 4599 head = page_buffers(pages[index]); 4600 if (!head) 4601 goto out; 4602 4603 index++; 4604 bh = head; 4605 do { 4606 if (end >= newex->ec_block + 4607 newex->ec_len) 4608 /* The buffer is out of 4609 * the request range. 4610 */ 4611 goto out; 4612 4613 if (buffer_mapped(bh) && 4614 end >= newex->ec_block) { 4615 start_index = index - 1; 4616 /* get the 1st mapped buffer. */ 4617 goto found_mapped_buffer; 4618 } 4619 4620 bh = bh->b_this_page; 4621 end++; 4622 } while (bh != head); 4623 4624 /* No mapped buffer in the range found in this page, 4625 * We need to look up next page. 4626 */ 4627 if (index >= ret) { 4628 /* There is no page left, but we need to limit 4629 * newex->ec_len. 4630 */ 4631 newex->ec_len = end - newex->ec_block; 4632 goto out; 4633 } 4634 goto next_page; 4635 } else { 4636 /*Find contiguous delayed buffers. */ 4637 if (ret > 0 && pages[0]->index == last_offset) 4638 head = page_buffers(pages[0]); 4639 bh = head; 4640 index = 1; 4641 start_index = 0; 4642 } 4643 4644found_mapped_buffer: 4645 if (bh != NULL && buffer_delay(bh)) { 4646 /* 1st or contiguous delayed buffer found. */ 4647 if (!(flags & FIEMAP_EXTENT_DELALLOC)) { 4648 /* 4649 * 1st delayed buffer found, record 4650 * the start of extent. 4651 */ 4652 flags |= FIEMAP_EXTENT_DELALLOC; 4653 newex->ec_block = end; 4654 logical = (__u64)end << blksize_bits; 4655 } 4656 /* Find contiguous delayed buffers. */ 4657 do { 4658 if (!buffer_delay(bh)) 4659 goto found_delayed_extent; 4660 bh = bh->b_this_page; 4661 end++; 4662 } while (bh != head); 4663 4664 for (; index < ret; index++) { 4665 if (!page_has_buffers(pages[index])) { 4666 bh = NULL; 4667 break; 4668 } 4669 head = page_buffers(pages[index]); 4670 if (!head) { 4671 bh = NULL; 4672 break; 4673 } 4674 4675 if (pages[index]->index != 4676 pages[start_index]->index + index 4677 - start_index) { 4678 /* Blocks are not contiguous. */ 4679 bh = NULL; 4680 break; 4681 } 4682 bh = head; 4683 do { 4684 if (!buffer_delay(bh)) 4685 /* Delayed-extent ends. */ 4686 goto found_delayed_extent; 4687 bh = bh->b_this_page; 4688 end++; 4689 } while (bh != head); 4690 } 4691 } else if (!(flags & FIEMAP_EXTENT_DELALLOC)) 4692 /* a hole found. */ 4693 goto out; 4694 4695found_delayed_extent: 4696 newex->ec_len = min(end - newex->ec_block, 4697 (ext4_lblk_t)EXT_INIT_MAX_LEN); 4698 if (ret == nr_pages && bh != NULL && 4699 newex->ec_len < EXT_INIT_MAX_LEN && 4700 buffer_delay(bh)) { 4701 /* Have not collected an extent and continue. */ 4702 for (index = 0; index < ret; index++) 4703 page_cache_release(pages[index]); 4704 goto repeat; 4705 } 4706 4707 for (index = 0; index < ret; index++) 4708 page_cache_release(pages[index]); 4709 kfree(pages); 4710 } 4711 4712 physical = (__u64)newex->ec_start << blksize_bits; 4713 length = (__u64)newex->ec_len << blksize_bits; 4714 4715 if (ex && ext4_ext_is_uninitialized(ex)) 4716 flags |= FIEMAP_EXTENT_UNWRITTEN; 4717 4718 if (next == EXT_MAX_BLOCKS) 4719 flags |= FIEMAP_EXTENT_LAST; 4720 4721 ret = fiemap_fill_next_extent(fieinfo, logical, physical, 4722 length, flags); 4723 if (ret < 0) 4724 return ret; 4725 if (ret == 1) 4726 return EXT_BREAK; 4727 return EXT_CONTINUE; 4728} 4729/* fiemap flags we can handle specified here */ 4730#define EXT4_FIEMAP_FLAGS (FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR) 4731 4732static int ext4_xattr_fiemap(struct inode *inode, 4733 struct fiemap_extent_info *fieinfo) 4734{ 4735 __u64 physical = 0; 4736 __u64 length; 4737 __u32 flags = FIEMAP_EXTENT_LAST; 4738 int blockbits = inode->i_sb->s_blocksize_bits; 4739 int error = 0; 4740 4741 /* in-inode? */ 4742 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) { 4743 struct ext4_iloc iloc; 4744 int offset; /* offset of xattr in inode */ 4745 4746 error = ext4_get_inode_loc(inode, &iloc); 4747 if (error) 4748 return error; 4749 physical = iloc.bh->b_blocknr << blockbits; 4750 offset = EXT4_GOOD_OLD_INODE_SIZE + 4751 EXT4_I(inode)->i_extra_isize; 4752 physical += offset; 4753 length = EXT4_SB(inode->i_sb)->s_inode_size - offset; 4754 flags |= FIEMAP_EXTENT_DATA_INLINE; 4755 brelse(iloc.bh); 4756 } else { /* external block */ 4757 physical = EXT4_I(inode)->i_file_acl << blockbits; 4758 length = inode->i_sb->s_blocksize; 4759 } 4760 4761 if (physical) 4762 error = fiemap_fill_next_extent(fieinfo, 0, physical, 4763 length, flags); 4764 return (error < 0 ? error : 0); 4765} 4766 4767/* 4768 * ext4_ext_punch_hole 4769 * 4770 * Punches a hole of "length" bytes in a file starting 4771 * at byte "offset" 4772 * 4773 * @inode: The inode of the file to punch a hole in 4774 * @offset: The starting byte offset of the hole 4775 * @length: The length of the hole 4776 * 4777 * Returns the number of blocks removed or negative on err 4778 */ 4779int ext4_ext_punch_hole(struct file *file, loff_t offset, loff_t length) 4780{ 4781 struct inode *inode = file->f_path.dentry->d_inode; 4782 struct super_block *sb = inode->i_sb; 4783 ext4_lblk_t first_block, stop_block; 4784 struct address_space *mapping = inode->i_mapping; 4785 handle_t *handle; 4786 loff_t first_page, last_page, page_len; 4787 loff_t first_page_offset, last_page_offset; 4788 int credits, err = 0; 4789 4790 /* No need to punch hole beyond i_size */ 4791 if (offset >= inode->i_size) 4792 return 0; 4793 4794 /* 4795 * If the hole extends beyond i_size, set the hole 4796 * to end after the page that contains i_size 4797 */ 4798 if (offset + length > inode->i_size) { 4799 length = inode->i_size + 4800 PAGE_CACHE_SIZE - (inode->i_size & (PAGE_CACHE_SIZE - 1)) - 4801 offset; 4802 } 4803 4804 first_page = (offset + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 4805 last_page = (offset + length) >> PAGE_CACHE_SHIFT; 4806 4807 first_page_offset = first_page << PAGE_CACHE_SHIFT; 4808 last_page_offset = last_page << PAGE_CACHE_SHIFT; 4809 4810 /* 4811 * Write out all dirty pages to avoid race conditions 4812 * Then release them. 4813 */ 4814 if (mapping->nrpages && mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) { 4815 err = filemap_write_and_wait_range(mapping, 4816 offset, offset + length - 1); 4817 4818 if (err) 4819 return err; 4820 } 4821 4822 /* Now release the pages */ 4823 if (last_page_offset > first_page_offset) { 4824 truncate_pagecache_range(inode, first_page_offset, 4825 last_page_offset - 1); 4826 } 4827 4828 /* finish any pending end_io work */ 4829 ext4_flush_completed_IO(inode); 4830 4831 credits = ext4_writepage_trans_blocks(inode); 4832 handle = ext4_journal_start(inode, credits); 4833 if (IS_ERR(handle)) 4834 return PTR_ERR(handle); 4835 4836 4837 /* 4838 * Now we need to zero out the non-page-aligned data in the 4839 * pages at the start and tail of the hole, and unmap the buffer 4840 * heads for the block aligned regions of the page that were 4841 * completely zeroed. 4842 */ 4843 if (first_page > last_page) { 4844 /* 4845 * If the file space being truncated is contained within a page 4846 * just zero out and unmap the middle of that page 4847 */ 4848 err = ext4_discard_partial_page_buffers(handle, 4849 mapping, offset, length, 0); 4850 4851 if (err) 4852 goto out; 4853 } else { 4854 /* 4855 * zero out and unmap the partial page that contains 4856 * the start of the hole 4857 */ 4858 page_len = first_page_offset - offset; 4859 if (page_len > 0) { 4860 err = ext4_discard_partial_page_buffers(handle, mapping, 4861 offset, page_len, 0); 4862 if (err) 4863 goto out; 4864 } 4865 4866 /* 4867 * zero out and unmap the partial page that contains 4868 * the end of the hole 4869 */ 4870 page_len = offset + length - last_page_offset; 4871 if (page_len > 0) { 4872 err = ext4_discard_partial_page_buffers(handle, mapping, 4873 last_page_offset, page_len, 0); 4874 if (err) 4875 goto out; 4876 } 4877 } 4878 4879 /* 4880 * If i_size is contained in the last page, we need to 4881 * unmap and zero the partial page after i_size 4882 */ 4883 if (inode->i_size >> PAGE_CACHE_SHIFT == last_page && 4884 inode->i_size % PAGE_CACHE_SIZE != 0) { 4885 4886 page_len = PAGE_CACHE_SIZE - 4887 (inode->i_size & (PAGE_CACHE_SIZE - 1)); 4888 4889 if (page_len > 0) { 4890 err = ext4_discard_partial_page_buffers(handle, 4891 mapping, inode->i_size, page_len, 0); 4892 4893 if (err) 4894 goto out; 4895 } 4896 } 4897 4898 first_block = (offset + sb->s_blocksize - 1) >> 4899 EXT4_BLOCK_SIZE_BITS(sb); 4900 stop_block = (offset + length) >> EXT4_BLOCK_SIZE_BITS(sb); 4901 4902 /* If there are no blocks to remove, return now */ 4903 if (first_block >= stop_block) 4904 goto out; 4905 4906 down_write(&EXT4_I(inode)->i_data_sem); 4907 ext4_ext_invalidate_cache(inode); 4908 ext4_discard_preallocations(inode); 4909 4910 err = ext4_ext_remove_space(inode, first_block, stop_block - 1); 4911 4912 ext4_ext_invalidate_cache(inode); 4913 ext4_discard_preallocations(inode); 4914 4915 if (IS_SYNC(inode)) 4916 ext4_handle_sync(handle); 4917 4918 up_write(&EXT4_I(inode)->i_data_sem); 4919 4920out: 4921 inode->i_mtime = inode->i_ctime = ext4_current_time(inode); 4922 ext4_mark_inode_dirty(handle, inode); 4923 ext4_journal_stop(handle); 4924 return err; 4925} 4926int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, 4927 __u64 start, __u64 len) 4928{ 4929 ext4_lblk_t start_blk; 4930 int error = 0; 4931 4932 /* fallback to generic here if not in extents fmt */ 4933 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) 4934 return generic_block_fiemap(inode, fieinfo, start, len, 4935 ext4_get_block); 4936 4937 if (fiemap_check_flags(fieinfo, EXT4_FIEMAP_FLAGS)) 4938 return -EBADR; 4939 4940 if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) { 4941 error = ext4_xattr_fiemap(inode, fieinfo); 4942 } else { 4943 ext4_lblk_t len_blks; 4944 __u64 last_blk; 4945 4946 start_blk = start >> inode->i_sb->s_blocksize_bits; 4947 last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits; 4948 if (last_blk >= EXT_MAX_BLOCKS) 4949 last_blk = EXT_MAX_BLOCKS-1; 4950 len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1; 4951 4952 /* 4953 * Walk the extent tree gathering extent information. 4954 * ext4_ext_fiemap_cb will push extents back to user. 4955 */ 4956 error = ext4_ext_walk_space(inode, start_blk, len_blks, 4957 ext4_ext_fiemap_cb, fieinfo); 4958 } 4959 4960 return error; 4961} 4962