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