extents.c revision 515f41c33a9d44a964264c9511ad2c869af1fac3
1/* 2 * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com 3 * Written by Alex Tomas <alex@clusterfs.com> 4 * 5 * Architecture independence: 6 * Copyright (c) 2005, Bull S.A. 7 * Written by Pierre Peiffer <pierre.peiffer@bull.net> 8 * 9 * This program is free software; you can redistribute it and/or modify 10 * it under the terms of the GNU General Public License version 2 as 11 * published by the Free Software Foundation. 12 * 13 * This program is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 * GNU General Public License for more details. 17 * 18 * You should have received a copy of the GNU General Public Licens 19 * along with this program; if not, write to the Free Software 20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111- 21 */ 22 23/* 24 * Extents support for EXT4 25 * 26 * TODO: 27 * - ext4*_error() should be used in some situations 28 * - analyze all BUG()/BUG_ON(), use -EIO where appropriate 29 * - smart tree reduction 30 */ 31 32#include <linux/module.h> 33#include <linux/fs.h> 34#include <linux/time.h> 35#include <linux/jbd2.h> 36#include <linux/highuid.h> 37#include <linux/pagemap.h> 38#include <linux/quotaops.h> 39#include <linux/string.h> 40#include <linux/slab.h> 41#include <linux/falloc.h> 42#include <asm/uaccess.h> 43#include <linux/fiemap.h> 44#include "ext4_jbd2.h" 45#include "ext4_extents.h" 46 47 48/* 49 * ext_pblock: 50 * combine low and high parts of physical block number into ext4_fsblk_t 51 */ 52ext4_fsblk_t ext_pblock(struct ext4_extent *ex) 53{ 54 ext4_fsblk_t block; 55 56 block = le32_to_cpu(ex->ee_start_lo); 57 block |= ((ext4_fsblk_t) le16_to_cpu(ex->ee_start_hi) << 31) << 1; 58 return block; 59} 60 61/* 62 * idx_pblock: 63 * combine low and high parts of a leaf physical block number into ext4_fsblk_t 64 */ 65ext4_fsblk_t idx_pblock(struct ext4_extent_idx *ix) 66{ 67 ext4_fsblk_t block; 68 69 block = le32_to_cpu(ix->ei_leaf_lo); 70 block |= ((ext4_fsblk_t) le16_to_cpu(ix->ei_leaf_hi) << 31) << 1; 71 return block; 72} 73 74/* 75 * ext4_ext_store_pblock: 76 * stores a large physical block number into an extent struct, 77 * breaking it into parts 78 */ 79void ext4_ext_store_pblock(struct ext4_extent *ex, ext4_fsblk_t pb) 80{ 81 ex->ee_start_lo = cpu_to_le32((unsigned long) (pb & 0xffffffff)); 82 ex->ee_start_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) & 0xffff); 83} 84 85/* 86 * ext4_idx_store_pblock: 87 * stores a large physical block number into an index struct, 88 * breaking it into parts 89 */ 90static void ext4_idx_store_pblock(struct ext4_extent_idx *ix, ext4_fsblk_t pb) 91{ 92 ix->ei_leaf_lo = cpu_to_le32((unsigned long) (pb & 0xffffffff)); 93 ix->ei_leaf_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) & 0xffff); 94} 95 96static int ext4_ext_truncate_extend_restart(handle_t *handle, 97 struct inode *inode, 98 int needed) 99{ 100 int err; 101 102 if (!ext4_handle_valid(handle)) 103 return 0; 104 if (handle->h_buffer_credits > needed) 105 return 0; 106 err = ext4_journal_extend(handle, needed); 107 if (err <= 0) 108 return err; 109 err = ext4_truncate_restart_trans(handle, inode, needed); 110 /* 111 * We have dropped i_data_sem so someone might have cached again 112 * an extent we are going to truncate. 113 */ 114 ext4_ext_invalidate_cache(inode); 115 116 return err; 117} 118 119/* 120 * could return: 121 * - EROFS 122 * - ENOMEM 123 */ 124static int ext4_ext_get_access(handle_t *handle, struct inode *inode, 125 struct ext4_ext_path *path) 126{ 127 if (path->p_bh) { 128 /* path points to block */ 129 return ext4_journal_get_write_access(handle, path->p_bh); 130 } 131 /* path points to leaf/index in inode body */ 132 /* we use in-core data, no need to protect them */ 133 return 0; 134} 135 136/* 137 * could return: 138 * - EROFS 139 * - ENOMEM 140 * - EIO 141 */ 142static int ext4_ext_dirty(handle_t *handle, struct inode *inode, 143 struct ext4_ext_path *path) 144{ 145 int err; 146 if (path->p_bh) { 147 /* path points to block */ 148 err = ext4_handle_dirty_metadata(handle, inode, path->p_bh); 149 } else { 150 /* path points to leaf/index in inode body */ 151 err = ext4_mark_inode_dirty(handle, inode); 152 } 153 return err; 154} 155 156static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode, 157 struct ext4_ext_path *path, 158 ext4_lblk_t block) 159{ 160 struct ext4_inode_info *ei = EXT4_I(inode); 161 ext4_fsblk_t bg_start; 162 ext4_fsblk_t last_block; 163 ext4_grpblk_t colour; 164 ext4_group_t block_group; 165 int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb)); 166 int depth; 167 168 if (path) { 169 struct ext4_extent *ex; 170 depth = path->p_depth; 171 172 /* try to predict block placement */ 173 ex = path[depth].p_ext; 174 if (ex) 175 return ext_pblock(ex)+(block-le32_to_cpu(ex->ee_block)); 176 177 /* it looks like index is empty; 178 * try to find starting block from index itself */ 179 if (path[depth].p_bh) 180 return path[depth].p_bh->b_blocknr; 181 } 182 183 /* OK. use inode's group */ 184 block_group = ei->i_block_group; 185 if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) { 186 /* 187 * If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME 188 * block groups per flexgroup, reserve the first block 189 * group for directories and special files. Regular 190 * files will start at the second block group. This 191 * tends to speed up directory access and improves 192 * fsck times. 193 */ 194 block_group &= ~(flex_size-1); 195 if (S_ISREG(inode->i_mode)) 196 block_group++; 197 } 198 bg_start = (block_group * EXT4_BLOCKS_PER_GROUP(inode->i_sb)) + 199 le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_first_data_block); 200 last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1; 201 202 /* 203 * If we are doing delayed allocation, we don't need take 204 * colour into account. 205 */ 206 if (test_opt(inode->i_sb, DELALLOC)) 207 return bg_start; 208 209 if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block) 210 colour = (current->pid % 16) * 211 (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16); 212 else 213 colour = (current->pid % 16) * ((last_block - bg_start) / 16); 214 return bg_start + colour + block; 215} 216 217/* 218 * Allocation for a meta data block 219 */ 220static ext4_fsblk_t 221ext4_ext_new_meta_block(handle_t *handle, struct inode *inode, 222 struct ext4_ext_path *path, 223 struct ext4_extent *ex, int *err) 224{ 225 ext4_fsblk_t goal, newblock; 226 227 goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block)); 228 newblock = ext4_new_meta_blocks(handle, inode, goal, NULL, err); 229 return newblock; 230} 231 232static inline int ext4_ext_space_block(struct inode *inode, int check) 233{ 234 int size; 235 236 size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header)) 237 / sizeof(struct ext4_extent); 238 if (!check) { 239#ifdef AGGRESSIVE_TEST 240 if (size > 6) 241 size = 6; 242#endif 243 } 244 return size; 245} 246 247static inline int ext4_ext_space_block_idx(struct inode *inode, int check) 248{ 249 int size; 250 251 size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header)) 252 / sizeof(struct ext4_extent_idx); 253 if (!check) { 254#ifdef AGGRESSIVE_TEST 255 if (size > 5) 256 size = 5; 257#endif 258 } 259 return size; 260} 261 262static inline int ext4_ext_space_root(struct inode *inode, int check) 263{ 264 int size; 265 266 size = sizeof(EXT4_I(inode)->i_data); 267 size -= sizeof(struct ext4_extent_header); 268 size /= sizeof(struct ext4_extent); 269 if (!check) { 270#ifdef AGGRESSIVE_TEST 271 if (size > 3) 272 size = 3; 273#endif 274 } 275 return size; 276} 277 278static inline int ext4_ext_space_root_idx(struct inode *inode, int check) 279{ 280 int size; 281 282 size = sizeof(EXT4_I(inode)->i_data); 283 size -= sizeof(struct ext4_extent_header); 284 size /= sizeof(struct ext4_extent_idx); 285 if (!check) { 286#ifdef AGGRESSIVE_TEST 287 if (size > 4) 288 size = 4; 289#endif 290 } 291 return size; 292} 293 294/* 295 * Calculate the number of metadata blocks needed 296 * to allocate @blocks 297 * Worse case is one block per extent 298 */ 299int ext4_ext_calc_metadata_amount(struct inode *inode, int blocks) 300{ 301 int lcap, icap, rcap, leafs, idxs, num; 302 int newextents = blocks; 303 304 rcap = ext4_ext_space_root_idx(inode, 0); 305 lcap = ext4_ext_space_block(inode, 0); 306 icap = ext4_ext_space_block_idx(inode, 0); 307 308 /* number of new leaf blocks needed */ 309 num = leafs = (newextents + lcap - 1) / lcap; 310 311 /* 312 * Worse case, we need separate index block(s) 313 * to link all new leaf blocks 314 */ 315 idxs = (leafs + icap - 1) / icap; 316 do { 317 num += idxs; 318 idxs = (idxs + icap - 1) / icap; 319 } while (idxs > rcap); 320 321 return num; 322} 323 324static int 325ext4_ext_max_entries(struct inode *inode, int depth) 326{ 327 int max; 328 329 if (depth == ext_depth(inode)) { 330 if (depth == 0) 331 max = ext4_ext_space_root(inode, 1); 332 else 333 max = ext4_ext_space_root_idx(inode, 1); 334 } else { 335 if (depth == 0) 336 max = ext4_ext_space_block(inode, 1); 337 else 338 max = ext4_ext_space_block_idx(inode, 1); 339 } 340 341 return max; 342} 343 344static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext) 345{ 346 ext4_fsblk_t block = ext_pblock(ext); 347 int len = ext4_ext_get_actual_len(ext); 348 349 return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, len); 350} 351 352static int ext4_valid_extent_idx(struct inode *inode, 353 struct ext4_extent_idx *ext_idx) 354{ 355 ext4_fsblk_t block = idx_pblock(ext_idx); 356 357 return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, 1); 358} 359 360static int ext4_valid_extent_entries(struct inode *inode, 361 struct ext4_extent_header *eh, 362 int depth) 363{ 364 struct ext4_extent *ext; 365 struct ext4_extent_idx *ext_idx; 366 unsigned short entries; 367 if (eh->eh_entries == 0) 368 return 1; 369 370 entries = le16_to_cpu(eh->eh_entries); 371 372 if (depth == 0) { 373 /* leaf entries */ 374 ext = EXT_FIRST_EXTENT(eh); 375 while (entries) { 376 if (!ext4_valid_extent(inode, ext)) 377 return 0; 378 ext++; 379 entries--; 380 } 381 } else { 382 ext_idx = EXT_FIRST_INDEX(eh); 383 while (entries) { 384 if (!ext4_valid_extent_idx(inode, ext_idx)) 385 return 0; 386 ext_idx++; 387 entries--; 388 } 389 } 390 return 1; 391} 392 393static int __ext4_ext_check(const char *function, struct inode *inode, 394 struct ext4_extent_header *eh, 395 int depth) 396{ 397 const char *error_msg; 398 int max = 0; 399 400 if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) { 401 error_msg = "invalid magic"; 402 goto corrupted; 403 } 404 if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) { 405 error_msg = "unexpected eh_depth"; 406 goto corrupted; 407 } 408 if (unlikely(eh->eh_max == 0)) { 409 error_msg = "invalid eh_max"; 410 goto corrupted; 411 } 412 max = ext4_ext_max_entries(inode, depth); 413 if (unlikely(le16_to_cpu(eh->eh_max) > max)) { 414 error_msg = "too large eh_max"; 415 goto corrupted; 416 } 417 if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) { 418 error_msg = "invalid eh_entries"; 419 goto corrupted; 420 } 421 if (!ext4_valid_extent_entries(inode, eh, depth)) { 422 error_msg = "invalid extent entries"; 423 goto corrupted; 424 } 425 return 0; 426 427corrupted: 428 ext4_error(inode->i_sb, function, 429 "bad header/extent in inode #%lu: %s - magic %x, " 430 "entries %u, max %u(%u), depth %u(%u)", 431 inode->i_ino, error_msg, le16_to_cpu(eh->eh_magic), 432 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max), 433 max, le16_to_cpu(eh->eh_depth), depth); 434 435 return -EIO; 436} 437 438#define ext4_ext_check(inode, eh, depth) \ 439 __ext4_ext_check(__func__, inode, eh, depth) 440 441int ext4_ext_check_inode(struct inode *inode) 442{ 443 return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode)); 444} 445 446#ifdef EXT_DEBUG 447static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path) 448{ 449 int k, l = path->p_depth; 450 451 ext_debug("path:"); 452 for (k = 0; k <= l; k++, path++) { 453 if (path->p_idx) { 454 ext_debug(" %d->%llu", le32_to_cpu(path->p_idx->ei_block), 455 idx_pblock(path->p_idx)); 456 } else if (path->p_ext) { 457 ext_debug(" %d:[%d]%d:%llu ", 458 le32_to_cpu(path->p_ext->ee_block), 459 ext4_ext_is_uninitialized(path->p_ext), 460 ext4_ext_get_actual_len(path->p_ext), 461 ext_pblock(path->p_ext)); 462 } else 463 ext_debug(" []"); 464 } 465 ext_debug("\n"); 466} 467 468static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path) 469{ 470 int depth = ext_depth(inode); 471 struct ext4_extent_header *eh; 472 struct ext4_extent *ex; 473 int i; 474 475 if (!path) 476 return; 477 478 eh = path[depth].p_hdr; 479 ex = EXT_FIRST_EXTENT(eh); 480 481 ext_debug("Displaying leaf extents for inode %lu\n", inode->i_ino); 482 483 for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) { 484 ext_debug("%d:[%d]%d:%llu ", le32_to_cpu(ex->ee_block), 485 ext4_ext_is_uninitialized(ex), 486 ext4_ext_get_actual_len(ex), ext_pblock(ex)); 487 } 488 ext_debug("\n"); 489} 490#else 491#define ext4_ext_show_path(inode, path) 492#define ext4_ext_show_leaf(inode, path) 493#endif 494 495void ext4_ext_drop_refs(struct ext4_ext_path *path) 496{ 497 int depth = path->p_depth; 498 int i; 499 500 for (i = 0; i <= depth; i++, path++) 501 if (path->p_bh) { 502 brelse(path->p_bh); 503 path->p_bh = NULL; 504 } 505} 506 507/* 508 * ext4_ext_binsearch_idx: 509 * binary search for the closest index of the given block 510 * the header must be checked before calling this 511 */ 512static void 513ext4_ext_binsearch_idx(struct inode *inode, 514 struct ext4_ext_path *path, ext4_lblk_t block) 515{ 516 struct ext4_extent_header *eh = path->p_hdr; 517 struct ext4_extent_idx *r, *l, *m; 518 519 520 ext_debug("binsearch for %u(idx): ", block); 521 522 l = EXT_FIRST_INDEX(eh) + 1; 523 r = EXT_LAST_INDEX(eh); 524 while (l <= r) { 525 m = l + (r - l) / 2; 526 if (block < le32_to_cpu(m->ei_block)) 527 r = m - 1; 528 else 529 l = m + 1; 530 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ei_block), 531 m, le32_to_cpu(m->ei_block), 532 r, le32_to_cpu(r->ei_block)); 533 } 534 535 path->p_idx = l - 1; 536 ext_debug(" -> %d->%lld ", le32_to_cpu(path->p_idx->ei_block), 537 idx_pblock(path->p_idx)); 538 539#ifdef CHECK_BINSEARCH 540 { 541 struct ext4_extent_idx *chix, *ix; 542 int k; 543 544 chix = ix = EXT_FIRST_INDEX(eh); 545 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) { 546 if (k != 0 && 547 le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) { 548 printk(KERN_DEBUG "k=%d, ix=0x%p, " 549 "first=0x%p\n", k, 550 ix, EXT_FIRST_INDEX(eh)); 551 printk(KERN_DEBUG "%u <= %u\n", 552 le32_to_cpu(ix->ei_block), 553 le32_to_cpu(ix[-1].ei_block)); 554 } 555 BUG_ON(k && le32_to_cpu(ix->ei_block) 556 <= le32_to_cpu(ix[-1].ei_block)); 557 if (block < le32_to_cpu(ix->ei_block)) 558 break; 559 chix = ix; 560 } 561 BUG_ON(chix != path->p_idx); 562 } 563#endif 564 565} 566 567/* 568 * ext4_ext_binsearch: 569 * binary search for closest extent of the given block 570 * the header must be checked before calling this 571 */ 572static void 573ext4_ext_binsearch(struct inode *inode, 574 struct ext4_ext_path *path, ext4_lblk_t block) 575{ 576 struct ext4_extent_header *eh = path->p_hdr; 577 struct ext4_extent *r, *l, *m; 578 579 if (eh->eh_entries == 0) { 580 /* 581 * this leaf is empty: 582 * we get such a leaf in split/add case 583 */ 584 return; 585 } 586 587 ext_debug("binsearch for %u: ", block); 588 589 l = EXT_FIRST_EXTENT(eh) + 1; 590 r = EXT_LAST_EXTENT(eh); 591 592 while (l <= r) { 593 m = l + (r - l) / 2; 594 if (block < le32_to_cpu(m->ee_block)) 595 r = m - 1; 596 else 597 l = m + 1; 598 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ee_block), 599 m, le32_to_cpu(m->ee_block), 600 r, le32_to_cpu(r->ee_block)); 601 } 602 603 path->p_ext = l - 1; 604 ext_debug(" -> %d:%llu:[%d]%d ", 605 le32_to_cpu(path->p_ext->ee_block), 606 ext_pblock(path->p_ext), 607 ext4_ext_is_uninitialized(path->p_ext), 608 ext4_ext_get_actual_len(path->p_ext)); 609 610#ifdef CHECK_BINSEARCH 611 { 612 struct ext4_extent *chex, *ex; 613 int k; 614 615 chex = ex = EXT_FIRST_EXTENT(eh); 616 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) { 617 BUG_ON(k && le32_to_cpu(ex->ee_block) 618 <= le32_to_cpu(ex[-1].ee_block)); 619 if (block < le32_to_cpu(ex->ee_block)) 620 break; 621 chex = ex; 622 } 623 BUG_ON(chex != path->p_ext); 624 } 625#endif 626 627} 628 629int ext4_ext_tree_init(handle_t *handle, struct inode *inode) 630{ 631 struct ext4_extent_header *eh; 632 633 eh = ext_inode_hdr(inode); 634 eh->eh_depth = 0; 635 eh->eh_entries = 0; 636 eh->eh_magic = EXT4_EXT_MAGIC; 637 eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode, 0)); 638 ext4_mark_inode_dirty(handle, inode); 639 ext4_ext_invalidate_cache(inode); 640 return 0; 641} 642 643struct ext4_ext_path * 644ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block, 645 struct ext4_ext_path *path) 646{ 647 struct ext4_extent_header *eh; 648 struct buffer_head *bh; 649 short int depth, i, ppos = 0, alloc = 0; 650 651 eh = ext_inode_hdr(inode); 652 depth = ext_depth(inode); 653 654 /* account possible depth increase */ 655 if (!path) { 656 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2), 657 GFP_NOFS); 658 if (!path) 659 return ERR_PTR(-ENOMEM); 660 alloc = 1; 661 } 662 path[0].p_hdr = eh; 663 path[0].p_bh = NULL; 664 665 i = depth; 666 /* walk through the tree */ 667 while (i) { 668 int need_to_validate = 0; 669 670 ext_debug("depth %d: num %d, max %d\n", 671 ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max)); 672 673 ext4_ext_binsearch_idx(inode, path + ppos, block); 674 path[ppos].p_block = idx_pblock(path[ppos].p_idx); 675 path[ppos].p_depth = i; 676 path[ppos].p_ext = NULL; 677 678 bh = sb_getblk(inode->i_sb, path[ppos].p_block); 679 if (unlikely(!bh)) 680 goto err; 681 if (!bh_uptodate_or_lock(bh)) { 682 if (bh_submit_read(bh) < 0) { 683 put_bh(bh); 684 goto err; 685 } 686 /* validate the extent entries */ 687 need_to_validate = 1; 688 } 689 eh = ext_block_hdr(bh); 690 ppos++; 691 BUG_ON(ppos > depth); 692 path[ppos].p_bh = bh; 693 path[ppos].p_hdr = eh; 694 i--; 695 696 if (need_to_validate && ext4_ext_check(inode, eh, i)) 697 goto err; 698 } 699 700 path[ppos].p_depth = i; 701 path[ppos].p_ext = NULL; 702 path[ppos].p_idx = NULL; 703 704 /* find extent */ 705 ext4_ext_binsearch(inode, path + ppos, block); 706 /* if not an empty leaf */ 707 if (path[ppos].p_ext) 708 path[ppos].p_block = ext_pblock(path[ppos].p_ext); 709 710 ext4_ext_show_path(inode, path); 711 712 return path; 713 714err: 715 ext4_ext_drop_refs(path); 716 if (alloc) 717 kfree(path); 718 return ERR_PTR(-EIO); 719} 720 721/* 722 * ext4_ext_insert_index: 723 * insert new index [@logical;@ptr] into the block at @curp; 724 * check where to insert: before @curp or after @curp 725 */ 726int ext4_ext_insert_index(handle_t *handle, struct inode *inode, 727 struct ext4_ext_path *curp, 728 int logical, ext4_fsblk_t ptr) 729{ 730 struct ext4_extent_idx *ix; 731 int len, err; 732 733 err = ext4_ext_get_access(handle, inode, curp); 734 if (err) 735 return err; 736 737 BUG_ON(logical == le32_to_cpu(curp->p_idx->ei_block)); 738 len = EXT_MAX_INDEX(curp->p_hdr) - curp->p_idx; 739 if (logical > le32_to_cpu(curp->p_idx->ei_block)) { 740 /* insert after */ 741 if (curp->p_idx != EXT_LAST_INDEX(curp->p_hdr)) { 742 len = (len - 1) * sizeof(struct ext4_extent_idx); 743 len = len < 0 ? 0 : len; 744 ext_debug("insert new index %d after: %llu. " 745 "move %d from 0x%p to 0x%p\n", 746 logical, ptr, len, 747 (curp->p_idx + 1), (curp->p_idx + 2)); 748 memmove(curp->p_idx + 2, curp->p_idx + 1, len); 749 } 750 ix = curp->p_idx + 1; 751 } else { 752 /* insert before */ 753 len = len * sizeof(struct ext4_extent_idx); 754 len = len < 0 ? 0 : len; 755 ext_debug("insert new index %d before: %llu. " 756 "move %d from 0x%p to 0x%p\n", 757 logical, ptr, len, 758 curp->p_idx, (curp->p_idx + 1)); 759 memmove(curp->p_idx + 1, curp->p_idx, len); 760 ix = curp->p_idx; 761 } 762 763 ix->ei_block = cpu_to_le32(logical); 764 ext4_idx_store_pblock(ix, ptr); 765 le16_add_cpu(&curp->p_hdr->eh_entries, 1); 766 767 BUG_ON(le16_to_cpu(curp->p_hdr->eh_entries) 768 > le16_to_cpu(curp->p_hdr->eh_max)); 769 BUG_ON(ix > EXT_LAST_INDEX(curp->p_hdr)); 770 771 err = ext4_ext_dirty(handle, inode, curp); 772 ext4_std_error(inode->i_sb, err); 773 774 return err; 775} 776 777/* 778 * ext4_ext_split: 779 * inserts new subtree into the path, using free index entry 780 * at depth @at: 781 * - allocates all needed blocks (new leaf and all intermediate index blocks) 782 * - makes decision where to split 783 * - moves remaining extents and index entries (right to the split point) 784 * into the newly allocated blocks 785 * - initializes subtree 786 */ 787static int ext4_ext_split(handle_t *handle, struct inode *inode, 788 struct ext4_ext_path *path, 789 struct ext4_extent *newext, int at) 790{ 791 struct buffer_head *bh = NULL; 792 int depth = ext_depth(inode); 793 struct ext4_extent_header *neh; 794 struct ext4_extent_idx *fidx; 795 struct ext4_extent *ex; 796 int i = at, k, m, a; 797 ext4_fsblk_t newblock, oldblock; 798 __le32 border; 799 ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */ 800 int err = 0; 801 802 /* make decision: where to split? */ 803 /* FIXME: now decision is simplest: at current extent */ 804 805 /* if current leaf will be split, then we should use 806 * border from split point */ 807 BUG_ON(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr)); 808 if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) { 809 border = path[depth].p_ext[1].ee_block; 810 ext_debug("leaf will be split." 811 " next leaf starts at %d\n", 812 le32_to_cpu(border)); 813 } else { 814 border = newext->ee_block; 815 ext_debug("leaf will be added." 816 " next leaf starts at %d\n", 817 le32_to_cpu(border)); 818 } 819 820 /* 821 * If error occurs, then we break processing 822 * and mark filesystem read-only. index won't 823 * be inserted and tree will be in consistent 824 * state. Next mount will repair buffers too. 825 */ 826 827 /* 828 * Get array to track all allocated blocks. 829 * We need this to handle errors and free blocks 830 * upon them. 831 */ 832 ablocks = kzalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS); 833 if (!ablocks) 834 return -ENOMEM; 835 836 /* allocate all needed blocks */ 837 ext_debug("allocate %d blocks for indexes/leaf\n", depth - at); 838 for (a = 0; a < depth - at; a++) { 839 newblock = ext4_ext_new_meta_block(handle, inode, path, 840 newext, &err); 841 if (newblock == 0) 842 goto cleanup; 843 ablocks[a] = newblock; 844 } 845 846 /* initialize new leaf */ 847 newblock = ablocks[--a]; 848 BUG_ON(newblock == 0); 849 bh = sb_getblk(inode->i_sb, newblock); 850 if (!bh) { 851 err = -EIO; 852 goto cleanup; 853 } 854 lock_buffer(bh); 855 856 err = ext4_journal_get_create_access(handle, bh); 857 if (err) 858 goto cleanup; 859 860 neh = ext_block_hdr(bh); 861 neh->eh_entries = 0; 862 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0)); 863 neh->eh_magic = EXT4_EXT_MAGIC; 864 neh->eh_depth = 0; 865 ex = EXT_FIRST_EXTENT(neh); 866 867 /* move remainder of path[depth] to the new leaf */ 868 BUG_ON(path[depth].p_hdr->eh_entries != path[depth].p_hdr->eh_max); 869 /* start copy from next extent */ 870 /* TODO: we could do it by single memmove */ 871 m = 0; 872 path[depth].p_ext++; 873 while (path[depth].p_ext <= 874 EXT_MAX_EXTENT(path[depth].p_hdr)) { 875 ext_debug("move %d:%llu:[%d]%d in new leaf %llu\n", 876 le32_to_cpu(path[depth].p_ext->ee_block), 877 ext_pblock(path[depth].p_ext), 878 ext4_ext_is_uninitialized(path[depth].p_ext), 879 ext4_ext_get_actual_len(path[depth].p_ext), 880 newblock); 881 /*memmove(ex++, path[depth].p_ext++, 882 sizeof(struct ext4_extent)); 883 neh->eh_entries++;*/ 884 path[depth].p_ext++; 885 m++; 886 } 887 if (m) { 888 memmove(ex, path[depth].p_ext-m, sizeof(struct ext4_extent)*m); 889 le16_add_cpu(&neh->eh_entries, m); 890 } 891 892 set_buffer_uptodate(bh); 893 unlock_buffer(bh); 894 895 err = ext4_handle_dirty_metadata(handle, inode, bh); 896 if (err) 897 goto cleanup; 898 brelse(bh); 899 bh = NULL; 900 901 /* correct old leaf */ 902 if (m) { 903 err = ext4_ext_get_access(handle, inode, path + depth); 904 if (err) 905 goto cleanup; 906 le16_add_cpu(&path[depth].p_hdr->eh_entries, -m); 907 err = ext4_ext_dirty(handle, inode, path + depth); 908 if (err) 909 goto cleanup; 910 911 } 912 913 /* create intermediate indexes */ 914 k = depth - at - 1; 915 BUG_ON(k < 0); 916 if (k) 917 ext_debug("create %d intermediate indices\n", k); 918 /* insert new index into current index block */ 919 /* current depth stored in i var */ 920 i = depth - 1; 921 while (k--) { 922 oldblock = newblock; 923 newblock = ablocks[--a]; 924 bh = sb_getblk(inode->i_sb, newblock); 925 if (!bh) { 926 err = -EIO; 927 goto cleanup; 928 } 929 lock_buffer(bh); 930 931 err = ext4_journal_get_create_access(handle, bh); 932 if (err) 933 goto cleanup; 934 935 neh = ext_block_hdr(bh); 936 neh->eh_entries = cpu_to_le16(1); 937 neh->eh_magic = EXT4_EXT_MAGIC; 938 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0)); 939 neh->eh_depth = cpu_to_le16(depth - i); 940 fidx = EXT_FIRST_INDEX(neh); 941 fidx->ei_block = border; 942 ext4_idx_store_pblock(fidx, oldblock); 943 944 ext_debug("int.index at %d (block %llu): %u -> %llu\n", 945 i, newblock, le32_to_cpu(border), oldblock); 946 /* copy indexes */ 947 m = 0; 948 path[i].p_idx++; 949 950 ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx, 951 EXT_MAX_INDEX(path[i].p_hdr)); 952 BUG_ON(EXT_MAX_INDEX(path[i].p_hdr) != 953 EXT_LAST_INDEX(path[i].p_hdr)); 954 while (path[i].p_idx <= EXT_MAX_INDEX(path[i].p_hdr)) { 955 ext_debug("%d: move %d:%llu in new index %llu\n", i, 956 le32_to_cpu(path[i].p_idx->ei_block), 957 idx_pblock(path[i].p_idx), 958 newblock); 959 /*memmove(++fidx, path[i].p_idx++, 960 sizeof(struct ext4_extent_idx)); 961 neh->eh_entries++; 962 BUG_ON(neh->eh_entries > neh->eh_max);*/ 963 path[i].p_idx++; 964 m++; 965 } 966 if (m) { 967 memmove(++fidx, path[i].p_idx - m, 968 sizeof(struct ext4_extent_idx) * m); 969 le16_add_cpu(&neh->eh_entries, m); 970 } 971 set_buffer_uptodate(bh); 972 unlock_buffer(bh); 973 974 err = ext4_handle_dirty_metadata(handle, inode, bh); 975 if (err) 976 goto cleanup; 977 brelse(bh); 978 bh = NULL; 979 980 /* correct old index */ 981 if (m) { 982 err = ext4_ext_get_access(handle, inode, path + i); 983 if (err) 984 goto cleanup; 985 le16_add_cpu(&path[i].p_hdr->eh_entries, -m); 986 err = ext4_ext_dirty(handle, inode, path + i); 987 if (err) 988 goto cleanup; 989 } 990 991 i--; 992 } 993 994 /* insert new index */ 995 err = ext4_ext_insert_index(handle, inode, path + at, 996 le32_to_cpu(border), newblock); 997 998cleanup: 999 if (bh) { 1000 if (buffer_locked(bh)) 1001 unlock_buffer(bh); 1002 brelse(bh); 1003 } 1004 1005 if (err) { 1006 /* free all allocated blocks in error case */ 1007 for (i = 0; i < depth; i++) { 1008 if (!ablocks[i]) 1009 continue; 1010 ext4_free_blocks(handle, inode, 0, ablocks[i], 1, 1011 EXT4_FREE_BLOCKS_METADATA); 1012 } 1013 } 1014 kfree(ablocks); 1015 1016 return err; 1017} 1018 1019/* 1020 * ext4_ext_grow_indepth: 1021 * implements tree growing procedure: 1022 * - allocates new block 1023 * - moves top-level data (index block or leaf) into the new block 1024 * - initializes new top-level, creating index that points to the 1025 * just created block 1026 */ 1027static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode, 1028 struct ext4_ext_path *path, 1029 struct ext4_extent *newext) 1030{ 1031 struct ext4_ext_path *curp = path; 1032 struct ext4_extent_header *neh; 1033 struct ext4_extent_idx *fidx; 1034 struct buffer_head *bh; 1035 ext4_fsblk_t newblock; 1036 int err = 0; 1037 1038 newblock = ext4_ext_new_meta_block(handle, inode, path, newext, &err); 1039 if (newblock == 0) 1040 return err; 1041 1042 bh = sb_getblk(inode->i_sb, newblock); 1043 if (!bh) { 1044 err = -EIO; 1045 ext4_std_error(inode->i_sb, err); 1046 return err; 1047 } 1048 lock_buffer(bh); 1049 1050 err = ext4_journal_get_create_access(handle, bh); 1051 if (err) { 1052 unlock_buffer(bh); 1053 goto out; 1054 } 1055 1056 /* move top-level index/leaf into new block */ 1057 memmove(bh->b_data, curp->p_hdr, sizeof(EXT4_I(inode)->i_data)); 1058 1059 /* set size of new block */ 1060 neh = ext_block_hdr(bh); 1061 /* old root could have indexes or leaves 1062 * so calculate e_max right way */ 1063 if (ext_depth(inode)) 1064 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0)); 1065 else 1066 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0)); 1067 neh->eh_magic = EXT4_EXT_MAGIC; 1068 set_buffer_uptodate(bh); 1069 unlock_buffer(bh); 1070 1071 err = ext4_handle_dirty_metadata(handle, inode, bh); 1072 if (err) 1073 goto out; 1074 1075 /* create index in new top-level index: num,max,pointer */ 1076 err = ext4_ext_get_access(handle, inode, curp); 1077 if (err) 1078 goto out; 1079 1080 curp->p_hdr->eh_magic = EXT4_EXT_MAGIC; 1081 curp->p_hdr->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode, 0)); 1082 curp->p_hdr->eh_entries = cpu_to_le16(1); 1083 curp->p_idx = EXT_FIRST_INDEX(curp->p_hdr); 1084 1085 if (path[0].p_hdr->eh_depth) 1086 curp->p_idx->ei_block = 1087 EXT_FIRST_INDEX(path[0].p_hdr)->ei_block; 1088 else 1089 curp->p_idx->ei_block = 1090 EXT_FIRST_EXTENT(path[0].p_hdr)->ee_block; 1091 ext4_idx_store_pblock(curp->p_idx, newblock); 1092 1093 neh = ext_inode_hdr(inode); 1094 fidx = EXT_FIRST_INDEX(neh); 1095 ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n", 1096 le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max), 1097 le32_to_cpu(fidx->ei_block), idx_pblock(fidx)); 1098 1099 neh->eh_depth = cpu_to_le16(path->p_depth + 1); 1100 err = ext4_ext_dirty(handle, inode, curp); 1101out: 1102 brelse(bh); 1103 1104 return err; 1105} 1106 1107/* 1108 * ext4_ext_create_new_leaf: 1109 * finds empty index and adds new leaf. 1110 * if no free index is found, then it requests in-depth growing. 1111 */ 1112static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode, 1113 struct ext4_ext_path *path, 1114 struct ext4_extent *newext) 1115{ 1116 struct ext4_ext_path *curp; 1117 int depth, i, err = 0; 1118 1119repeat: 1120 i = depth = ext_depth(inode); 1121 1122 /* walk up to the tree and look for free index entry */ 1123 curp = path + depth; 1124 while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) { 1125 i--; 1126 curp--; 1127 } 1128 1129 /* we use already allocated block for index block, 1130 * so subsequent data blocks should be contiguous */ 1131 if (EXT_HAS_FREE_INDEX(curp)) { 1132 /* if we found index with free entry, then use that 1133 * entry: create all needed subtree and add new leaf */ 1134 err = ext4_ext_split(handle, inode, path, newext, i); 1135 if (err) 1136 goto out; 1137 1138 /* refill path */ 1139 ext4_ext_drop_refs(path); 1140 path = ext4_ext_find_extent(inode, 1141 (ext4_lblk_t)le32_to_cpu(newext->ee_block), 1142 path); 1143 if (IS_ERR(path)) 1144 err = PTR_ERR(path); 1145 } else { 1146 /* tree is full, time to grow in depth */ 1147 err = ext4_ext_grow_indepth(handle, inode, path, newext); 1148 if (err) 1149 goto out; 1150 1151 /* refill path */ 1152 ext4_ext_drop_refs(path); 1153 path = ext4_ext_find_extent(inode, 1154 (ext4_lblk_t)le32_to_cpu(newext->ee_block), 1155 path); 1156 if (IS_ERR(path)) { 1157 err = PTR_ERR(path); 1158 goto out; 1159 } 1160 1161 /* 1162 * only first (depth 0 -> 1) produces free space; 1163 * in all other cases we have to split the grown tree 1164 */ 1165 depth = ext_depth(inode); 1166 if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) { 1167 /* now we need to split */ 1168 goto repeat; 1169 } 1170 } 1171 1172out: 1173 return err; 1174} 1175 1176/* 1177 * search the closest allocated block to the left for *logical 1178 * and returns it at @logical + it's physical address at @phys 1179 * if *logical is the smallest allocated block, the function 1180 * returns 0 at @phys 1181 * return value contains 0 (success) or error code 1182 */ 1183int 1184ext4_ext_search_left(struct inode *inode, struct ext4_ext_path *path, 1185 ext4_lblk_t *logical, ext4_fsblk_t *phys) 1186{ 1187 struct ext4_extent_idx *ix; 1188 struct ext4_extent *ex; 1189 int depth, ee_len; 1190 1191 BUG_ON(path == NULL); 1192 depth = path->p_depth; 1193 *phys = 0; 1194 1195 if (depth == 0 && path->p_ext == NULL) 1196 return 0; 1197 1198 /* usually extent in the path covers blocks smaller 1199 * then *logical, but it can be that extent is the 1200 * first one in the file */ 1201 1202 ex = path[depth].p_ext; 1203 ee_len = ext4_ext_get_actual_len(ex); 1204 if (*logical < le32_to_cpu(ex->ee_block)) { 1205 BUG_ON(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex); 1206 while (--depth >= 0) { 1207 ix = path[depth].p_idx; 1208 BUG_ON(ix != EXT_FIRST_INDEX(path[depth].p_hdr)); 1209 } 1210 return 0; 1211 } 1212 1213 BUG_ON(*logical < (le32_to_cpu(ex->ee_block) + ee_len)); 1214 1215 *logical = le32_to_cpu(ex->ee_block) + ee_len - 1; 1216 *phys = ext_pblock(ex) + ee_len - 1; 1217 return 0; 1218} 1219 1220/* 1221 * search the closest allocated block to the right for *logical 1222 * and returns it at @logical + it's physical address at @phys 1223 * if *logical is the smallest allocated block, the function 1224 * returns 0 at @phys 1225 * return value contains 0 (success) or error code 1226 */ 1227int 1228ext4_ext_search_right(struct inode *inode, struct ext4_ext_path *path, 1229 ext4_lblk_t *logical, ext4_fsblk_t *phys) 1230{ 1231 struct buffer_head *bh = NULL; 1232 struct ext4_extent_header *eh; 1233 struct ext4_extent_idx *ix; 1234 struct ext4_extent *ex; 1235 ext4_fsblk_t block; 1236 int depth; /* Note, NOT eh_depth; depth from top of tree */ 1237 int ee_len; 1238 1239 BUG_ON(path == NULL); 1240 depth = path->p_depth; 1241 *phys = 0; 1242 1243 if (depth == 0 && path->p_ext == NULL) 1244 return 0; 1245 1246 /* usually extent in the path covers blocks smaller 1247 * then *logical, but it can be that extent is the 1248 * first one in the file */ 1249 1250 ex = path[depth].p_ext; 1251 ee_len = ext4_ext_get_actual_len(ex); 1252 if (*logical < le32_to_cpu(ex->ee_block)) { 1253 BUG_ON(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex); 1254 while (--depth >= 0) { 1255 ix = path[depth].p_idx; 1256 BUG_ON(ix != EXT_FIRST_INDEX(path[depth].p_hdr)); 1257 } 1258 *logical = le32_to_cpu(ex->ee_block); 1259 *phys = ext_pblock(ex); 1260 return 0; 1261 } 1262 1263 BUG_ON(*logical < (le32_to_cpu(ex->ee_block) + ee_len)); 1264 1265 if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) { 1266 /* next allocated block in this leaf */ 1267 ex++; 1268 *logical = le32_to_cpu(ex->ee_block); 1269 *phys = ext_pblock(ex); 1270 return 0; 1271 } 1272 1273 /* go up and search for index to the right */ 1274 while (--depth >= 0) { 1275 ix = path[depth].p_idx; 1276 if (ix != EXT_LAST_INDEX(path[depth].p_hdr)) 1277 goto got_index; 1278 } 1279 1280 /* we've gone up to the root and found no index to the right */ 1281 return 0; 1282 1283got_index: 1284 /* we've found index to the right, let's 1285 * follow it and find the closest allocated 1286 * block to the right */ 1287 ix++; 1288 block = idx_pblock(ix); 1289 while (++depth < path->p_depth) { 1290 bh = sb_bread(inode->i_sb, block); 1291 if (bh == NULL) 1292 return -EIO; 1293 eh = ext_block_hdr(bh); 1294 /* subtract from p_depth to get proper eh_depth */ 1295 if (ext4_ext_check(inode, eh, path->p_depth - depth)) { 1296 put_bh(bh); 1297 return -EIO; 1298 } 1299 ix = EXT_FIRST_INDEX(eh); 1300 block = idx_pblock(ix); 1301 put_bh(bh); 1302 } 1303 1304 bh = sb_bread(inode->i_sb, block); 1305 if (bh == NULL) 1306 return -EIO; 1307 eh = ext_block_hdr(bh); 1308 if (ext4_ext_check(inode, eh, path->p_depth - depth)) { 1309 put_bh(bh); 1310 return -EIO; 1311 } 1312 ex = EXT_FIRST_EXTENT(eh); 1313 *logical = le32_to_cpu(ex->ee_block); 1314 *phys = ext_pblock(ex); 1315 put_bh(bh); 1316 return 0; 1317} 1318 1319/* 1320 * ext4_ext_next_allocated_block: 1321 * returns allocated block in subsequent extent or EXT_MAX_BLOCK. 1322 * NOTE: it considers block number from index entry as 1323 * allocated block. Thus, index entries have to be consistent 1324 * with leaves. 1325 */ 1326static ext4_lblk_t 1327ext4_ext_next_allocated_block(struct ext4_ext_path *path) 1328{ 1329 int depth; 1330 1331 BUG_ON(path == NULL); 1332 depth = path->p_depth; 1333 1334 if (depth == 0 && path->p_ext == NULL) 1335 return EXT_MAX_BLOCK; 1336 1337 while (depth >= 0) { 1338 if (depth == path->p_depth) { 1339 /* leaf */ 1340 if (path[depth].p_ext != 1341 EXT_LAST_EXTENT(path[depth].p_hdr)) 1342 return le32_to_cpu(path[depth].p_ext[1].ee_block); 1343 } else { 1344 /* index */ 1345 if (path[depth].p_idx != 1346 EXT_LAST_INDEX(path[depth].p_hdr)) 1347 return le32_to_cpu(path[depth].p_idx[1].ei_block); 1348 } 1349 depth--; 1350 } 1351 1352 return EXT_MAX_BLOCK; 1353} 1354 1355/* 1356 * ext4_ext_next_leaf_block: 1357 * returns first allocated block from next leaf or EXT_MAX_BLOCK 1358 */ 1359static ext4_lblk_t ext4_ext_next_leaf_block(struct inode *inode, 1360 struct ext4_ext_path *path) 1361{ 1362 int depth; 1363 1364 BUG_ON(path == NULL); 1365 depth = path->p_depth; 1366 1367 /* zero-tree has no leaf blocks at all */ 1368 if (depth == 0) 1369 return EXT_MAX_BLOCK; 1370 1371 /* go to index block */ 1372 depth--; 1373 1374 while (depth >= 0) { 1375 if (path[depth].p_idx != 1376 EXT_LAST_INDEX(path[depth].p_hdr)) 1377 return (ext4_lblk_t) 1378 le32_to_cpu(path[depth].p_idx[1].ei_block); 1379 depth--; 1380 } 1381 1382 return EXT_MAX_BLOCK; 1383} 1384 1385/* 1386 * ext4_ext_correct_indexes: 1387 * if leaf gets modified and modified extent is first in the leaf, 1388 * then we have to correct all indexes above. 1389 * TODO: do we need to correct tree in all cases? 1390 */ 1391static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode, 1392 struct ext4_ext_path *path) 1393{ 1394 struct ext4_extent_header *eh; 1395 int depth = ext_depth(inode); 1396 struct ext4_extent *ex; 1397 __le32 border; 1398 int k, err = 0; 1399 1400 eh = path[depth].p_hdr; 1401 ex = path[depth].p_ext; 1402 BUG_ON(ex == NULL); 1403 BUG_ON(eh == NULL); 1404 1405 if (depth == 0) { 1406 /* there is no tree at all */ 1407 return 0; 1408 } 1409 1410 if (ex != EXT_FIRST_EXTENT(eh)) { 1411 /* we correct tree if first leaf got modified only */ 1412 return 0; 1413 } 1414 1415 /* 1416 * TODO: we need correction if border is smaller than current one 1417 */ 1418 k = depth - 1; 1419 border = path[depth].p_ext->ee_block; 1420 err = ext4_ext_get_access(handle, inode, path + k); 1421 if (err) 1422 return err; 1423 path[k].p_idx->ei_block = border; 1424 err = ext4_ext_dirty(handle, inode, path + k); 1425 if (err) 1426 return err; 1427 1428 while (k--) { 1429 /* change all left-side indexes */ 1430 if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr)) 1431 break; 1432 err = ext4_ext_get_access(handle, inode, path + k); 1433 if (err) 1434 break; 1435 path[k].p_idx->ei_block = border; 1436 err = ext4_ext_dirty(handle, inode, path + k); 1437 if (err) 1438 break; 1439 } 1440 1441 return err; 1442} 1443 1444int 1445ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1, 1446 struct ext4_extent *ex2) 1447{ 1448 unsigned short ext1_ee_len, ext2_ee_len, max_len; 1449 1450 /* 1451 * Make sure that either both extents are uninitialized, or 1452 * both are _not_. 1453 */ 1454 if (ext4_ext_is_uninitialized(ex1) ^ ext4_ext_is_uninitialized(ex2)) 1455 return 0; 1456 1457 if (ext4_ext_is_uninitialized(ex1)) 1458 max_len = EXT_UNINIT_MAX_LEN; 1459 else 1460 max_len = EXT_INIT_MAX_LEN; 1461 1462 ext1_ee_len = ext4_ext_get_actual_len(ex1); 1463 ext2_ee_len = ext4_ext_get_actual_len(ex2); 1464 1465 if (le32_to_cpu(ex1->ee_block) + ext1_ee_len != 1466 le32_to_cpu(ex2->ee_block)) 1467 return 0; 1468 1469 /* 1470 * To allow future support for preallocated extents to be added 1471 * as an RO_COMPAT feature, refuse to merge to extents if 1472 * this can result in the top bit of ee_len being set. 1473 */ 1474 if (ext1_ee_len + ext2_ee_len > max_len) 1475 return 0; 1476#ifdef AGGRESSIVE_TEST 1477 if (ext1_ee_len >= 4) 1478 return 0; 1479#endif 1480 1481 if (ext_pblock(ex1) + ext1_ee_len == ext_pblock(ex2)) 1482 return 1; 1483 return 0; 1484} 1485 1486/* 1487 * This function tries to merge the "ex" extent to the next extent in the tree. 1488 * It always tries to merge towards right. If you want to merge towards 1489 * left, pass "ex - 1" as argument instead of "ex". 1490 * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns 1491 * 1 if they got merged. 1492 */ 1493int ext4_ext_try_to_merge(struct inode *inode, 1494 struct ext4_ext_path *path, 1495 struct ext4_extent *ex) 1496{ 1497 struct ext4_extent_header *eh; 1498 unsigned int depth, len; 1499 int merge_done = 0; 1500 int uninitialized = 0; 1501 1502 depth = ext_depth(inode); 1503 BUG_ON(path[depth].p_hdr == NULL); 1504 eh = path[depth].p_hdr; 1505 1506 while (ex < EXT_LAST_EXTENT(eh)) { 1507 if (!ext4_can_extents_be_merged(inode, ex, ex + 1)) 1508 break; 1509 /* merge with next extent! */ 1510 if (ext4_ext_is_uninitialized(ex)) 1511 uninitialized = 1; 1512 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex) 1513 + ext4_ext_get_actual_len(ex + 1)); 1514 if (uninitialized) 1515 ext4_ext_mark_uninitialized(ex); 1516 1517 if (ex + 1 < EXT_LAST_EXTENT(eh)) { 1518 len = (EXT_LAST_EXTENT(eh) - ex - 1) 1519 * sizeof(struct ext4_extent); 1520 memmove(ex + 1, ex + 2, len); 1521 } 1522 le16_add_cpu(&eh->eh_entries, -1); 1523 merge_done = 1; 1524 WARN_ON(eh->eh_entries == 0); 1525 if (!eh->eh_entries) 1526 ext4_error(inode->i_sb, "ext4_ext_try_to_merge", 1527 "inode#%lu, eh->eh_entries = 0!", inode->i_ino); 1528 } 1529 1530 return merge_done; 1531} 1532 1533/* 1534 * check if a portion of the "newext" extent overlaps with an 1535 * existing extent. 1536 * 1537 * If there is an overlap discovered, it updates the length of the newext 1538 * such that there will be no overlap, and then returns 1. 1539 * If there is no overlap found, it returns 0. 1540 */ 1541unsigned int ext4_ext_check_overlap(struct inode *inode, 1542 struct ext4_extent *newext, 1543 struct ext4_ext_path *path) 1544{ 1545 ext4_lblk_t b1, b2; 1546 unsigned int depth, len1; 1547 unsigned int ret = 0; 1548 1549 b1 = le32_to_cpu(newext->ee_block); 1550 len1 = ext4_ext_get_actual_len(newext); 1551 depth = ext_depth(inode); 1552 if (!path[depth].p_ext) 1553 goto out; 1554 b2 = le32_to_cpu(path[depth].p_ext->ee_block); 1555 1556 /* 1557 * get the next allocated block if the extent in the path 1558 * is before the requested block(s) 1559 */ 1560 if (b2 < b1) { 1561 b2 = ext4_ext_next_allocated_block(path); 1562 if (b2 == EXT_MAX_BLOCK) 1563 goto out; 1564 } 1565 1566 /* check for wrap through zero on extent logical start block*/ 1567 if (b1 + len1 < b1) { 1568 len1 = EXT_MAX_BLOCK - b1; 1569 newext->ee_len = cpu_to_le16(len1); 1570 ret = 1; 1571 } 1572 1573 /* check for overlap */ 1574 if (b1 + len1 > b2) { 1575 newext->ee_len = cpu_to_le16(b2 - b1); 1576 ret = 1; 1577 } 1578out: 1579 return ret; 1580} 1581 1582/* 1583 * ext4_ext_insert_extent: 1584 * tries to merge requsted extent into the existing extent or 1585 * inserts requested extent as new one into the tree, 1586 * creating new leaf in the no-space case. 1587 */ 1588int ext4_ext_insert_extent(handle_t *handle, struct inode *inode, 1589 struct ext4_ext_path *path, 1590 struct ext4_extent *newext, int flag) 1591{ 1592 struct ext4_extent_header *eh; 1593 struct ext4_extent *ex, *fex; 1594 struct ext4_extent *nearex; /* nearest extent */ 1595 struct ext4_ext_path *npath = NULL; 1596 int depth, len, err; 1597 ext4_lblk_t next; 1598 unsigned uninitialized = 0; 1599 1600 BUG_ON(ext4_ext_get_actual_len(newext) == 0); 1601 depth = ext_depth(inode); 1602 ex = path[depth].p_ext; 1603 BUG_ON(path[depth].p_hdr == NULL); 1604 1605 /* try to insert block into found extent and return */ 1606 if (ex && (flag != EXT4_GET_BLOCKS_DIO_CREATE_EXT) 1607 && ext4_can_extents_be_merged(inode, ex, newext)) { 1608 ext_debug("append [%d]%d block to %d:[%d]%d (from %llu)\n", 1609 ext4_ext_is_uninitialized(newext), 1610 ext4_ext_get_actual_len(newext), 1611 le32_to_cpu(ex->ee_block), 1612 ext4_ext_is_uninitialized(ex), 1613 ext4_ext_get_actual_len(ex), ext_pblock(ex)); 1614 err = ext4_ext_get_access(handle, inode, path + depth); 1615 if (err) 1616 return err; 1617 1618 /* 1619 * ext4_can_extents_be_merged should have checked that either 1620 * both extents are uninitialized, or both aren't. Thus we 1621 * need to check only one of them here. 1622 */ 1623 if (ext4_ext_is_uninitialized(ex)) 1624 uninitialized = 1; 1625 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex) 1626 + ext4_ext_get_actual_len(newext)); 1627 if (uninitialized) 1628 ext4_ext_mark_uninitialized(ex); 1629 eh = path[depth].p_hdr; 1630 nearex = ex; 1631 goto merge; 1632 } 1633 1634repeat: 1635 depth = ext_depth(inode); 1636 eh = path[depth].p_hdr; 1637 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) 1638 goto has_space; 1639 1640 /* probably next leaf has space for us? */ 1641 fex = EXT_LAST_EXTENT(eh); 1642 next = ext4_ext_next_leaf_block(inode, path); 1643 if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block) 1644 && next != EXT_MAX_BLOCK) { 1645 ext_debug("next leaf block - %d\n", next); 1646 BUG_ON(npath != NULL); 1647 npath = ext4_ext_find_extent(inode, next, NULL); 1648 if (IS_ERR(npath)) 1649 return PTR_ERR(npath); 1650 BUG_ON(npath->p_depth != path->p_depth); 1651 eh = npath[depth].p_hdr; 1652 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) { 1653 ext_debug("next leaf isnt full(%d)\n", 1654 le16_to_cpu(eh->eh_entries)); 1655 path = npath; 1656 goto repeat; 1657 } 1658 ext_debug("next leaf has no free space(%d,%d)\n", 1659 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max)); 1660 } 1661 1662 /* 1663 * There is no free space in the found leaf. 1664 * We're gonna add a new leaf in the tree. 1665 */ 1666 err = ext4_ext_create_new_leaf(handle, inode, path, newext); 1667 if (err) 1668 goto cleanup; 1669 depth = ext_depth(inode); 1670 eh = path[depth].p_hdr; 1671 1672has_space: 1673 nearex = path[depth].p_ext; 1674 1675 err = ext4_ext_get_access(handle, inode, path + depth); 1676 if (err) 1677 goto cleanup; 1678 1679 if (!nearex) { 1680 /* there is no extent in this leaf, create first one */ 1681 ext_debug("first extent in the leaf: %d:%llu:[%d]%d\n", 1682 le32_to_cpu(newext->ee_block), 1683 ext_pblock(newext), 1684 ext4_ext_is_uninitialized(newext), 1685 ext4_ext_get_actual_len(newext)); 1686 path[depth].p_ext = EXT_FIRST_EXTENT(eh); 1687 } else if (le32_to_cpu(newext->ee_block) 1688 > le32_to_cpu(nearex->ee_block)) { 1689/* BUG_ON(newext->ee_block == nearex->ee_block); */ 1690 if (nearex != EXT_LAST_EXTENT(eh)) { 1691 len = EXT_MAX_EXTENT(eh) - nearex; 1692 len = (len - 1) * sizeof(struct ext4_extent); 1693 len = len < 0 ? 0 : len; 1694 ext_debug("insert %d:%llu:[%d]%d after: nearest 0x%p, " 1695 "move %d from 0x%p to 0x%p\n", 1696 le32_to_cpu(newext->ee_block), 1697 ext_pblock(newext), 1698 ext4_ext_is_uninitialized(newext), 1699 ext4_ext_get_actual_len(newext), 1700 nearex, len, nearex + 1, nearex + 2); 1701 memmove(nearex + 2, nearex + 1, len); 1702 } 1703 path[depth].p_ext = nearex + 1; 1704 } else { 1705 BUG_ON(newext->ee_block == nearex->ee_block); 1706 len = (EXT_MAX_EXTENT(eh) - nearex) * sizeof(struct ext4_extent); 1707 len = len < 0 ? 0 : len; 1708 ext_debug("insert %d:%llu:[%d]%d before: nearest 0x%p, " 1709 "move %d from 0x%p to 0x%p\n", 1710 le32_to_cpu(newext->ee_block), 1711 ext_pblock(newext), 1712 ext4_ext_is_uninitialized(newext), 1713 ext4_ext_get_actual_len(newext), 1714 nearex, len, nearex + 1, nearex + 2); 1715 memmove(nearex + 1, nearex, len); 1716 path[depth].p_ext = nearex; 1717 } 1718 1719 le16_add_cpu(&eh->eh_entries, 1); 1720 nearex = path[depth].p_ext; 1721 nearex->ee_block = newext->ee_block; 1722 ext4_ext_store_pblock(nearex, ext_pblock(newext)); 1723 nearex->ee_len = newext->ee_len; 1724 1725merge: 1726 /* try to merge extents to the right */ 1727 if (flag != EXT4_GET_BLOCKS_DIO_CREATE_EXT) 1728 ext4_ext_try_to_merge(inode, path, nearex); 1729 1730 /* try to merge extents to the left */ 1731 1732 /* time to correct all indexes above */ 1733 err = ext4_ext_correct_indexes(handle, inode, path); 1734 if (err) 1735 goto cleanup; 1736 1737 err = ext4_ext_dirty(handle, inode, path + depth); 1738 1739cleanup: 1740 if (npath) { 1741 ext4_ext_drop_refs(npath); 1742 kfree(npath); 1743 } 1744 ext4_ext_invalidate_cache(inode); 1745 return err; 1746} 1747 1748int ext4_ext_walk_space(struct inode *inode, ext4_lblk_t block, 1749 ext4_lblk_t num, ext_prepare_callback func, 1750 void *cbdata) 1751{ 1752 struct ext4_ext_path *path = NULL; 1753 struct ext4_ext_cache cbex; 1754 struct ext4_extent *ex; 1755 ext4_lblk_t next, start = 0, end = 0; 1756 ext4_lblk_t last = block + num; 1757 int depth, exists, err = 0; 1758 1759 BUG_ON(func == NULL); 1760 BUG_ON(inode == NULL); 1761 1762 while (block < last && block != EXT_MAX_BLOCK) { 1763 num = last - block; 1764 /* find extent for this block */ 1765 down_read(&EXT4_I(inode)->i_data_sem); 1766 path = ext4_ext_find_extent(inode, block, path); 1767 up_read(&EXT4_I(inode)->i_data_sem); 1768 if (IS_ERR(path)) { 1769 err = PTR_ERR(path); 1770 path = NULL; 1771 break; 1772 } 1773 1774 depth = ext_depth(inode); 1775 BUG_ON(path[depth].p_hdr == NULL); 1776 ex = path[depth].p_ext; 1777 next = ext4_ext_next_allocated_block(path); 1778 1779 exists = 0; 1780 if (!ex) { 1781 /* there is no extent yet, so try to allocate 1782 * all requested space */ 1783 start = block; 1784 end = block + num; 1785 } else if (le32_to_cpu(ex->ee_block) > block) { 1786 /* need to allocate space before found extent */ 1787 start = block; 1788 end = le32_to_cpu(ex->ee_block); 1789 if (block + num < end) 1790 end = block + num; 1791 } else if (block >= le32_to_cpu(ex->ee_block) 1792 + ext4_ext_get_actual_len(ex)) { 1793 /* need to allocate space after found extent */ 1794 start = block; 1795 end = block + num; 1796 if (end >= next) 1797 end = next; 1798 } else if (block >= le32_to_cpu(ex->ee_block)) { 1799 /* 1800 * some part of requested space is covered 1801 * by found extent 1802 */ 1803 start = block; 1804 end = le32_to_cpu(ex->ee_block) 1805 + ext4_ext_get_actual_len(ex); 1806 if (block + num < end) 1807 end = block + num; 1808 exists = 1; 1809 } else { 1810 BUG(); 1811 } 1812 BUG_ON(end <= start); 1813 1814 if (!exists) { 1815 cbex.ec_block = start; 1816 cbex.ec_len = end - start; 1817 cbex.ec_start = 0; 1818 cbex.ec_type = EXT4_EXT_CACHE_GAP; 1819 } else { 1820 cbex.ec_block = le32_to_cpu(ex->ee_block); 1821 cbex.ec_len = ext4_ext_get_actual_len(ex); 1822 cbex.ec_start = ext_pblock(ex); 1823 cbex.ec_type = EXT4_EXT_CACHE_EXTENT; 1824 } 1825 1826 BUG_ON(cbex.ec_len == 0); 1827 err = func(inode, path, &cbex, ex, cbdata); 1828 ext4_ext_drop_refs(path); 1829 1830 if (err < 0) 1831 break; 1832 1833 if (err == EXT_REPEAT) 1834 continue; 1835 else if (err == EXT_BREAK) { 1836 err = 0; 1837 break; 1838 } 1839 1840 if (ext_depth(inode) != depth) { 1841 /* depth was changed. we have to realloc path */ 1842 kfree(path); 1843 path = NULL; 1844 } 1845 1846 block = cbex.ec_block + cbex.ec_len; 1847 } 1848 1849 if (path) { 1850 ext4_ext_drop_refs(path); 1851 kfree(path); 1852 } 1853 1854 return err; 1855} 1856 1857static void 1858ext4_ext_put_in_cache(struct inode *inode, ext4_lblk_t block, 1859 __u32 len, ext4_fsblk_t start, int type) 1860{ 1861 struct ext4_ext_cache *cex; 1862 BUG_ON(len == 0); 1863 spin_lock(&EXT4_I(inode)->i_block_reservation_lock); 1864 cex = &EXT4_I(inode)->i_cached_extent; 1865 cex->ec_type = type; 1866 cex->ec_block = block; 1867 cex->ec_len = len; 1868 cex->ec_start = start; 1869 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock); 1870} 1871 1872/* 1873 * ext4_ext_put_gap_in_cache: 1874 * calculate boundaries of the gap that the requested block fits into 1875 * and cache this gap 1876 */ 1877static void 1878ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path, 1879 ext4_lblk_t block) 1880{ 1881 int depth = ext_depth(inode); 1882 unsigned long len; 1883 ext4_lblk_t lblock; 1884 struct ext4_extent *ex; 1885 1886 ex = path[depth].p_ext; 1887 if (ex == NULL) { 1888 /* there is no extent yet, so gap is [0;-] */ 1889 lblock = 0; 1890 len = EXT_MAX_BLOCK; 1891 ext_debug("cache gap(whole file):"); 1892 } else if (block < le32_to_cpu(ex->ee_block)) { 1893 lblock = block; 1894 len = le32_to_cpu(ex->ee_block) - block; 1895 ext_debug("cache gap(before): %u [%u:%u]", 1896 block, 1897 le32_to_cpu(ex->ee_block), 1898 ext4_ext_get_actual_len(ex)); 1899 } else if (block >= le32_to_cpu(ex->ee_block) 1900 + ext4_ext_get_actual_len(ex)) { 1901 ext4_lblk_t next; 1902 lblock = le32_to_cpu(ex->ee_block) 1903 + ext4_ext_get_actual_len(ex); 1904 1905 next = ext4_ext_next_allocated_block(path); 1906 ext_debug("cache gap(after): [%u:%u] %u", 1907 le32_to_cpu(ex->ee_block), 1908 ext4_ext_get_actual_len(ex), 1909 block); 1910 BUG_ON(next == lblock); 1911 len = next - lblock; 1912 } else { 1913 lblock = len = 0; 1914 BUG(); 1915 } 1916 1917 ext_debug(" -> %u:%lu\n", lblock, len); 1918 ext4_ext_put_in_cache(inode, lblock, len, 0, EXT4_EXT_CACHE_GAP); 1919} 1920 1921static int 1922ext4_ext_in_cache(struct inode *inode, ext4_lblk_t block, 1923 struct ext4_extent *ex) 1924{ 1925 struct ext4_ext_cache *cex; 1926 int ret = EXT4_EXT_CACHE_NO; 1927 1928 /* 1929 * We borrow i_block_reservation_lock to protect i_cached_extent 1930 */ 1931 spin_lock(&EXT4_I(inode)->i_block_reservation_lock); 1932 cex = &EXT4_I(inode)->i_cached_extent; 1933 1934 /* has cache valid data? */ 1935 if (cex->ec_type == EXT4_EXT_CACHE_NO) 1936 goto errout; 1937 1938 BUG_ON(cex->ec_type != EXT4_EXT_CACHE_GAP && 1939 cex->ec_type != EXT4_EXT_CACHE_EXTENT); 1940 if (block >= cex->ec_block && block < cex->ec_block + cex->ec_len) { 1941 ex->ee_block = cpu_to_le32(cex->ec_block); 1942 ext4_ext_store_pblock(ex, cex->ec_start); 1943 ex->ee_len = cpu_to_le16(cex->ec_len); 1944 ext_debug("%u cached by %u:%u:%llu\n", 1945 block, 1946 cex->ec_block, cex->ec_len, cex->ec_start); 1947 ret = cex->ec_type; 1948 } 1949errout: 1950 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock); 1951 return ret; 1952} 1953 1954/* 1955 * ext4_ext_rm_idx: 1956 * removes index from the index block. 1957 * It's used in truncate case only, thus all requests are for 1958 * last index in the block only. 1959 */ 1960static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode, 1961 struct ext4_ext_path *path) 1962{ 1963 int err; 1964 ext4_fsblk_t leaf; 1965 1966 /* free index block */ 1967 path--; 1968 leaf = idx_pblock(path->p_idx); 1969 BUG_ON(path->p_hdr->eh_entries == 0); 1970 err = ext4_ext_get_access(handle, inode, path); 1971 if (err) 1972 return err; 1973 le16_add_cpu(&path->p_hdr->eh_entries, -1); 1974 err = ext4_ext_dirty(handle, inode, path); 1975 if (err) 1976 return err; 1977 ext_debug("index is empty, remove it, free block %llu\n", leaf); 1978 ext4_free_blocks(handle, inode, 0, leaf, 1, 1979 EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET); 1980 return err; 1981} 1982 1983/* 1984 * ext4_ext_calc_credits_for_single_extent: 1985 * This routine returns max. credits that needed to insert an extent 1986 * to the extent tree. 1987 * When pass the actual path, the caller should calculate credits 1988 * under i_data_sem. 1989 */ 1990int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks, 1991 struct ext4_ext_path *path) 1992{ 1993 if (path) { 1994 int depth = ext_depth(inode); 1995 int ret = 0; 1996 1997 /* probably there is space in leaf? */ 1998 if (le16_to_cpu(path[depth].p_hdr->eh_entries) 1999 < le16_to_cpu(path[depth].p_hdr->eh_max)) { 2000 2001 /* 2002 * There are some space in the leaf tree, no 2003 * need to account for leaf block credit 2004 * 2005 * bitmaps and block group descriptor blocks 2006 * and other metadat blocks still need to be 2007 * accounted. 2008 */ 2009 /* 1 bitmap, 1 block group descriptor */ 2010 ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb); 2011 return ret; 2012 } 2013 } 2014 2015 return ext4_chunk_trans_blocks(inode, nrblocks); 2016} 2017 2018/* 2019 * How many index/leaf blocks need to change/allocate to modify nrblocks? 2020 * 2021 * if nrblocks are fit in a single extent (chunk flag is 1), then 2022 * in the worse case, each tree level index/leaf need to be changed 2023 * if the tree split due to insert a new extent, then the old tree 2024 * index/leaf need to be updated too 2025 * 2026 * If the nrblocks are discontiguous, they could cause 2027 * the whole tree split more than once, but this is really rare. 2028 */ 2029int ext4_ext_index_trans_blocks(struct inode *inode, int nrblocks, int chunk) 2030{ 2031 int index; 2032 int depth = ext_depth(inode); 2033 2034 if (chunk) 2035 index = depth * 2; 2036 else 2037 index = depth * 3; 2038 2039 return index; 2040} 2041 2042static int ext4_remove_blocks(handle_t *handle, struct inode *inode, 2043 struct ext4_extent *ex, 2044 ext4_lblk_t from, ext4_lblk_t to) 2045{ 2046 unsigned short ee_len = ext4_ext_get_actual_len(ex); 2047 int flags = EXT4_FREE_BLOCKS_FORGET; 2048 2049 if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) 2050 flags |= EXT4_FREE_BLOCKS_METADATA; 2051#ifdef EXTENTS_STATS 2052 { 2053 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 2054 spin_lock(&sbi->s_ext_stats_lock); 2055 sbi->s_ext_blocks += ee_len; 2056 sbi->s_ext_extents++; 2057 if (ee_len < sbi->s_ext_min) 2058 sbi->s_ext_min = ee_len; 2059 if (ee_len > sbi->s_ext_max) 2060 sbi->s_ext_max = ee_len; 2061 if (ext_depth(inode) > sbi->s_depth_max) 2062 sbi->s_depth_max = ext_depth(inode); 2063 spin_unlock(&sbi->s_ext_stats_lock); 2064 } 2065#endif 2066 if (from >= le32_to_cpu(ex->ee_block) 2067 && to == le32_to_cpu(ex->ee_block) + ee_len - 1) { 2068 /* tail removal */ 2069 ext4_lblk_t num; 2070 ext4_fsblk_t start; 2071 2072 num = le32_to_cpu(ex->ee_block) + ee_len - from; 2073 start = ext_pblock(ex) + ee_len - num; 2074 ext_debug("free last %u blocks starting %llu\n", num, start); 2075 ext4_free_blocks(handle, inode, 0, start, num, flags); 2076 } else if (from == le32_to_cpu(ex->ee_block) 2077 && to <= le32_to_cpu(ex->ee_block) + ee_len - 1) { 2078 printk(KERN_INFO "strange request: removal %u-%u from %u:%u\n", 2079 from, to, le32_to_cpu(ex->ee_block), ee_len); 2080 } else { 2081 printk(KERN_INFO "strange request: removal(2) " 2082 "%u-%u from %u:%u\n", 2083 from, to, le32_to_cpu(ex->ee_block), ee_len); 2084 } 2085 return 0; 2086} 2087 2088static int 2089ext4_ext_rm_leaf(handle_t *handle, struct inode *inode, 2090 struct ext4_ext_path *path, ext4_lblk_t start) 2091{ 2092 int err = 0, correct_index = 0; 2093 int depth = ext_depth(inode), credits; 2094 struct ext4_extent_header *eh; 2095 ext4_lblk_t a, b, block; 2096 unsigned num; 2097 ext4_lblk_t ex_ee_block; 2098 unsigned short ex_ee_len; 2099 unsigned uninitialized = 0; 2100 struct ext4_extent *ex; 2101 2102 /* the header must be checked already in ext4_ext_remove_space() */ 2103 ext_debug("truncate since %u in leaf\n", start); 2104 if (!path[depth].p_hdr) 2105 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh); 2106 eh = path[depth].p_hdr; 2107 BUG_ON(eh == NULL); 2108 2109 /* find where to start removing */ 2110 ex = EXT_LAST_EXTENT(eh); 2111 2112 ex_ee_block = le32_to_cpu(ex->ee_block); 2113 ex_ee_len = ext4_ext_get_actual_len(ex); 2114 2115 while (ex >= EXT_FIRST_EXTENT(eh) && 2116 ex_ee_block + ex_ee_len > start) { 2117 2118 if (ext4_ext_is_uninitialized(ex)) 2119 uninitialized = 1; 2120 else 2121 uninitialized = 0; 2122 2123 ext_debug("remove ext %u:[%d]%d\n", ex_ee_block, 2124 uninitialized, ex_ee_len); 2125 path[depth].p_ext = ex; 2126 2127 a = ex_ee_block > start ? ex_ee_block : start; 2128 b = ex_ee_block + ex_ee_len - 1 < EXT_MAX_BLOCK ? 2129 ex_ee_block + ex_ee_len - 1 : EXT_MAX_BLOCK; 2130 2131 ext_debug(" border %u:%u\n", a, b); 2132 2133 if (a != ex_ee_block && b != ex_ee_block + ex_ee_len - 1) { 2134 block = 0; 2135 num = 0; 2136 BUG(); 2137 } else if (a != ex_ee_block) { 2138 /* remove tail of the extent */ 2139 block = ex_ee_block; 2140 num = a - block; 2141 } else if (b != ex_ee_block + ex_ee_len - 1) { 2142 /* remove head of the extent */ 2143 block = a; 2144 num = b - a; 2145 /* there is no "make a hole" API yet */ 2146 BUG(); 2147 } else { 2148 /* remove whole extent: excellent! */ 2149 block = ex_ee_block; 2150 num = 0; 2151 BUG_ON(a != ex_ee_block); 2152 BUG_ON(b != ex_ee_block + ex_ee_len - 1); 2153 } 2154 2155 /* 2156 * 3 for leaf, sb, and inode plus 2 (bmap and group 2157 * descriptor) for each block group; assume two block 2158 * groups plus ex_ee_len/blocks_per_block_group for 2159 * the worst case 2160 */ 2161 credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb)); 2162 if (ex == EXT_FIRST_EXTENT(eh)) { 2163 correct_index = 1; 2164 credits += (ext_depth(inode)) + 1; 2165 } 2166 credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb); 2167 2168 err = ext4_ext_truncate_extend_restart(handle, inode, credits); 2169 if (err) 2170 goto out; 2171 2172 err = ext4_ext_get_access(handle, inode, path + depth); 2173 if (err) 2174 goto out; 2175 2176 err = ext4_remove_blocks(handle, inode, ex, a, b); 2177 if (err) 2178 goto out; 2179 2180 if (num == 0) { 2181 /* this extent is removed; mark slot entirely unused */ 2182 ext4_ext_store_pblock(ex, 0); 2183 le16_add_cpu(&eh->eh_entries, -1); 2184 } 2185 2186 ex->ee_block = cpu_to_le32(block); 2187 ex->ee_len = cpu_to_le16(num); 2188 /* 2189 * Do not mark uninitialized if all the blocks in the 2190 * extent have been removed. 2191 */ 2192 if (uninitialized && num) 2193 ext4_ext_mark_uninitialized(ex); 2194 2195 err = ext4_ext_dirty(handle, inode, path + depth); 2196 if (err) 2197 goto out; 2198 2199 ext_debug("new extent: %u:%u:%llu\n", block, num, 2200 ext_pblock(ex)); 2201 ex--; 2202 ex_ee_block = le32_to_cpu(ex->ee_block); 2203 ex_ee_len = ext4_ext_get_actual_len(ex); 2204 } 2205 2206 if (correct_index && eh->eh_entries) 2207 err = ext4_ext_correct_indexes(handle, inode, path); 2208 2209 /* if this leaf is free, then we should 2210 * remove it from index block above */ 2211 if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL) 2212 err = ext4_ext_rm_idx(handle, inode, path + depth); 2213 2214out: 2215 return err; 2216} 2217 2218/* 2219 * ext4_ext_more_to_rm: 2220 * returns 1 if current index has to be freed (even partial) 2221 */ 2222static int 2223ext4_ext_more_to_rm(struct ext4_ext_path *path) 2224{ 2225 BUG_ON(path->p_idx == NULL); 2226 2227 if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr)) 2228 return 0; 2229 2230 /* 2231 * if truncate on deeper level happened, it wasn't partial, 2232 * so we have to consider current index for truncation 2233 */ 2234 if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block) 2235 return 0; 2236 return 1; 2237} 2238 2239static int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start) 2240{ 2241 struct super_block *sb = inode->i_sb; 2242 int depth = ext_depth(inode); 2243 struct ext4_ext_path *path; 2244 handle_t *handle; 2245 int i = 0, err = 0; 2246 2247 ext_debug("truncate since %u\n", start); 2248 2249 /* probably first extent we're gonna free will be last in block */ 2250 handle = ext4_journal_start(inode, depth + 1); 2251 if (IS_ERR(handle)) 2252 return PTR_ERR(handle); 2253 2254 ext4_ext_invalidate_cache(inode); 2255 2256 /* 2257 * We start scanning from right side, freeing all the blocks 2258 * after i_size and walking into the tree depth-wise. 2259 */ 2260 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1), GFP_NOFS); 2261 if (path == NULL) { 2262 ext4_journal_stop(handle); 2263 return -ENOMEM; 2264 } 2265 path[0].p_hdr = ext_inode_hdr(inode); 2266 if (ext4_ext_check(inode, path[0].p_hdr, depth)) { 2267 err = -EIO; 2268 goto out; 2269 } 2270 path[0].p_depth = depth; 2271 2272 while (i >= 0 && err == 0) { 2273 if (i == depth) { 2274 /* this is leaf block */ 2275 err = ext4_ext_rm_leaf(handle, inode, path, start); 2276 /* root level has p_bh == NULL, brelse() eats this */ 2277 brelse(path[i].p_bh); 2278 path[i].p_bh = NULL; 2279 i--; 2280 continue; 2281 } 2282 2283 /* this is index block */ 2284 if (!path[i].p_hdr) { 2285 ext_debug("initialize header\n"); 2286 path[i].p_hdr = ext_block_hdr(path[i].p_bh); 2287 } 2288 2289 if (!path[i].p_idx) { 2290 /* this level hasn't been touched yet */ 2291 path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr); 2292 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1; 2293 ext_debug("init index ptr: hdr 0x%p, num %d\n", 2294 path[i].p_hdr, 2295 le16_to_cpu(path[i].p_hdr->eh_entries)); 2296 } else { 2297 /* we were already here, see at next index */ 2298 path[i].p_idx--; 2299 } 2300 2301 ext_debug("level %d - index, first 0x%p, cur 0x%p\n", 2302 i, EXT_FIRST_INDEX(path[i].p_hdr), 2303 path[i].p_idx); 2304 if (ext4_ext_more_to_rm(path + i)) { 2305 struct buffer_head *bh; 2306 /* go to the next level */ 2307 ext_debug("move to level %d (block %llu)\n", 2308 i + 1, idx_pblock(path[i].p_idx)); 2309 memset(path + i + 1, 0, sizeof(*path)); 2310 bh = sb_bread(sb, idx_pblock(path[i].p_idx)); 2311 if (!bh) { 2312 /* should we reset i_size? */ 2313 err = -EIO; 2314 break; 2315 } 2316 if (WARN_ON(i + 1 > depth)) { 2317 err = -EIO; 2318 break; 2319 } 2320 if (ext4_ext_check(inode, ext_block_hdr(bh), 2321 depth - i - 1)) { 2322 err = -EIO; 2323 break; 2324 } 2325 path[i + 1].p_bh = bh; 2326 2327 /* save actual number of indexes since this 2328 * number is changed at the next iteration */ 2329 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries); 2330 i++; 2331 } else { 2332 /* we finished processing this index, go up */ 2333 if (path[i].p_hdr->eh_entries == 0 && i > 0) { 2334 /* index is empty, remove it; 2335 * handle must be already prepared by the 2336 * truncatei_leaf() */ 2337 err = ext4_ext_rm_idx(handle, inode, path + i); 2338 } 2339 /* root level has p_bh == NULL, brelse() eats this */ 2340 brelse(path[i].p_bh); 2341 path[i].p_bh = NULL; 2342 i--; 2343 ext_debug("return to level %d\n", i); 2344 } 2345 } 2346 2347 /* TODO: flexible tree reduction should be here */ 2348 if (path->p_hdr->eh_entries == 0) { 2349 /* 2350 * truncate to zero freed all the tree, 2351 * so we need to correct eh_depth 2352 */ 2353 err = ext4_ext_get_access(handle, inode, path); 2354 if (err == 0) { 2355 ext_inode_hdr(inode)->eh_depth = 0; 2356 ext_inode_hdr(inode)->eh_max = 2357 cpu_to_le16(ext4_ext_space_root(inode, 0)); 2358 err = ext4_ext_dirty(handle, inode, path); 2359 } 2360 } 2361out: 2362 ext4_ext_drop_refs(path); 2363 kfree(path); 2364 ext4_journal_stop(handle); 2365 2366 return err; 2367} 2368 2369/* 2370 * called at mount time 2371 */ 2372void ext4_ext_init(struct super_block *sb) 2373{ 2374 /* 2375 * possible initialization would be here 2376 */ 2377 2378 if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) { 2379#if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS) 2380 printk(KERN_INFO "EXT4-fs: file extents enabled"); 2381#ifdef AGGRESSIVE_TEST 2382 printk(", aggressive tests"); 2383#endif 2384#ifdef CHECK_BINSEARCH 2385 printk(", check binsearch"); 2386#endif 2387#ifdef EXTENTS_STATS 2388 printk(", stats"); 2389#endif 2390 printk("\n"); 2391#endif 2392#ifdef EXTENTS_STATS 2393 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock); 2394 EXT4_SB(sb)->s_ext_min = 1 << 30; 2395 EXT4_SB(sb)->s_ext_max = 0; 2396#endif 2397 } 2398} 2399 2400/* 2401 * called at umount time 2402 */ 2403void ext4_ext_release(struct super_block *sb) 2404{ 2405 if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) 2406 return; 2407 2408#ifdef EXTENTS_STATS 2409 if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) { 2410 struct ext4_sb_info *sbi = EXT4_SB(sb); 2411 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n", 2412 sbi->s_ext_blocks, sbi->s_ext_extents, 2413 sbi->s_ext_blocks / sbi->s_ext_extents); 2414 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n", 2415 sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max); 2416 } 2417#endif 2418} 2419 2420static void bi_complete(struct bio *bio, int error) 2421{ 2422 complete((struct completion *)bio->bi_private); 2423} 2424 2425/* FIXME!! we need to try to merge to left or right after zero-out */ 2426static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex) 2427{ 2428 int ret = -EIO; 2429 struct bio *bio; 2430 int blkbits, blocksize; 2431 sector_t ee_pblock; 2432 struct completion event; 2433 unsigned int ee_len, len, done, offset; 2434 2435 2436 blkbits = inode->i_blkbits; 2437 blocksize = inode->i_sb->s_blocksize; 2438 ee_len = ext4_ext_get_actual_len(ex); 2439 ee_pblock = ext_pblock(ex); 2440 2441 /* convert ee_pblock to 512 byte sectors */ 2442 ee_pblock = ee_pblock << (blkbits - 9); 2443 2444 while (ee_len > 0) { 2445 2446 if (ee_len > BIO_MAX_PAGES) 2447 len = BIO_MAX_PAGES; 2448 else 2449 len = ee_len; 2450 2451 bio = bio_alloc(GFP_NOIO, len); 2452 bio->bi_sector = ee_pblock; 2453 bio->bi_bdev = inode->i_sb->s_bdev; 2454 2455 done = 0; 2456 offset = 0; 2457 while (done < len) { 2458 ret = bio_add_page(bio, ZERO_PAGE(0), 2459 blocksize, offset); 2460 if (ret != blocksize) { 2461 /* 2462 * We can't add any more pages because of 2463 * hardware limitations. Start a new bio. 2464 */ 2465 break; 2466 } 2467 done++; 2468 offset += blocksize; 2469 if (offset >= PAGE_CACHE_SIZE) 2470 offset = 0; 2471 } 2472 2473 init_completion(&event); 2474 bio->bi_private = &event; 2475 bio->bi_end_io = bi_complete; 2476 submit_bio(WRITE, bio); 2477 wait_for_completion(&event); 2478 2479 if (test_bit(BIO_UPTODATE, &bio->bi_flags)) 2480 ret = 0; 2481 else { 2482 ret = -EIO; 2483 break; 2484 } 2485 bio_put(bio); 2486 ee_len -= done; 2487 ee_pblock += done << (blkbits - 9); 2488 } 2489 return ret; 2490} 2491 2492#define EXT4_EXT_ZERO_LEN 7 2493/* 2494 * This function is called by ext4_ext_get_blocks() if someone tries to write 2495 * to an uninitialized extent. It may result in splitting the uninitialized 2496 * extent into multiple extents (upto three - one initialized and two 2497 * uninitialized). 2498 * There are three possibilities: 2499 * a> There is no split required: Entire extent should be initialized 2500 * b> Splits in two extents: Write is happening at either end of the extent 2501 * c> Splits in three extents: Somone is writing in middle of the extent 2502 */ 2503static int ext4_ext_convert_to_initialized(handle_t *handle, 2504 struct inode *inode, 2505 struct ext4_ext_path *path, 2506 ext4_lblk_t iblock, 2507 unsigned int max_blocks) 2508{ 2509 struct ext4_extent *ex, newex, orig_ex; 2510 struct ext4_extent *ex1 = NULL; 2511 struct ext4_extent *ex2 = NULL; 2512 struct ext4_extent *ex3 = NULL; 2513 struct ext4_extent_header *eh; 2514 ext4_lblk_t ee_block; 2515 unsigned int allocated, ee_len, depth; 2516 ext4_fsblk_t newblock; 2517 int err = 0; 2518 int ret = 0; 2519 2520 depth = ext_depth(inode); 2521 eh = path[depth].p_hdr; 2522 ex = path[depth].p_ext; 2523 ee_block = le32_to_cpu(ex->ee_block); 2524 ee_len = ext4_ext_get_actual_len(ex); 2525 allocated = ee_len - (iblock - ee_block); 2526 newblock = iblock - ee_block + ext_pblock(ex); 2527 ex2 = ex; 2528 orig_ex.ee_block = ex->ee_block; 2529 orig_ex.ee_len = cpu_to_le16(ee_len); 2530 ext4_ext_store_pblock(&orig_ex, ext_pblock(ex)); 2531 2532 err = ext4_ext_get_access(handle, inode, path + depth); 2533 if (err) 2534 goto out; 2535 /* If extent has less than 2*EXT4_EXT_ZERO_LEN zerout directly */ 2536 if (ee_len <= 2*EXT4_EXT_ZERO_LEN) { 2537 err = ext4_ext_zeroout(inode, &orig_ex); 2538 if (err) 2539 goto fix_extent_len; 2540 /* update the extent length and mark as initialized */ 2541 ex->ee_block = orig_ex.ee_block; 2542 ex->ee_len = orig_ex.ee_len; 2543 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2544 ext4_ext_dirty(handle, inode, path + depth); 2545 /* zeroed the full extent */ 2546 return allocated; 2547 } 2548 2549 /* ex1: ee_block to iblock - 1 : uninitialized */ 2550 if (iblock > ee_block) { 2551 ex1 = ex; 2552 ex1->ee_len = cpu_to_le16(iblock - ee_block); 2553 ext4_ext_mark_uninitialized(ex1); 2554 ex2 = &newex; 2555 } 2556 /* 2557 * for sanity, update the length of the ex2 extent before 2558 * we insert ex3, if ex1 is NULL. This is to avoid temporary 2559 * overlap of blocks. 2560 */ 2561 if (!ex1 && allocated > max_blocks) 2562 ex2->ee_len = cpu_to_le16(max_blocks); 2563 /* ex3: to ee_block + ee_len : uninitialised */ 2564 if (allocated > max_blocks) { 2565 unsigned int newdepth; 2566 /* If extent has less than EXT4_EXT_ZERO_LEN zerout directly */ 2567 if (allocated <= EXT4_EXT_ZERO_LEN) { 2568 /* 2569 * iblock == ee_block is handled by the zerouout 2570 * at the beginning. 2571 * Mark first half uninitialized. 2572 * Mark second half initialized and zero out the 2573 * initialized extent 2574 */ 2575 ex->ee_block = orig_ex.ee_block; 2576 ex->ee_len = cpu_to_le16(ee_len - allocated); 2577 ext4_ext_mark_uninitialized(ex); 2578 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2579 ext4_ext_dirty(handle, inode, path + depth); 2580 2581 ex3 = &newex; 2582 ex3->ee_block = cpu_to_le32(iblock); 2583 ext4_ext_store_pblock(ex3, newblock); 2584 ex3->ee_len = cpu_to_le16(allocated); 2585 err = ext4_ext_insert_extent(handle, inode, path, 2586 ex3, 0); 2587 if (err == -ENOSPC) { 2588 err = ext4_ext_zeroout(inode, &orig_ex); 2589 if (err) 2590 goto fix_extent_len; 2591 ex->ee_block = orig_ex.ee_block; 2592 ex->ee_len = orig_ex.ee_len; 2593 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2594 ext4_ext_dirty(handle, inode, path + depth); 2595 /* blocks available from iblock */ 2596 return allocated; 2597 2598 } else if (err) 2599 goto fix_extent_len; 2600 2601 /* 2602 * We need to zero out the second half because 2603 * an fallocate request can update file size and 2604 * converting the second half to initialized extent 2605 * implies that we can leak some junk data to user 2606 * space. 2607 */ 2608 err = ext4_ext_zeroout(inode, ex3); 2609 if (err) { 2610 /* 2611 * We should actually mark the 2612 * second half as uninit and return error 2613 * Insert would have changed the extent 2614 */ 2615 depth = ext_depth(inode); 2616 ext4_ext_drop_refs(path); 2617 path = ext4_ext_find_extent(inode, 2618 iblock, path); 2619 if (IS_ERR(path)) { 2620 err = PTR_ERR(path); 2621 return err; 2622 } 2623 /* get the second half extent details */ 2624 ex = path[depth].p_ext; 2625 err = ext4_ext_get_access(handle, inode, 2626 path + depth); 2627 if (err) 2628 return err; 2629 ext4_ext_mark_uninitialized(ex); 2630 ext4_ext_dirty(handle, inode, path + depth); 2631 return err; 2632 } 2633 2634 /* zeroed the second half */ 2635 return allocated; 2636 } 2637 ex3 = &newex; 2638 ex3->ee_block = cpu_to_le32(iblock + max_blocks); 2639 ext4_ext_store_pblock(ex3, newblock + max_blocks); 2640 ex3->ee_len = cpu_to_le16(allocated - max_blocks); 2641 ext4_ext_mark_uninitialized(ex3); 2642 err = ext4_ext_insert_extent(handle, inode, path, ex3, 0); 2643 if (err == -ENOSPC) { 2644 err = ext4_ext_zeroout(inode, &orig_ex); 2645 if (err) 2646 goto fix_extent_len; 2647 /* update the extent length and mark as initialized */ 2648 ex->ee_block = orig_ex.ee_block; 2649 ex->ee_len = orig_ex.ee_len; 2650 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2651 ext4_ext_dirty(handle, inode, path + depth); 2652 /* zeroed the full extent */ 2653 /* blocks available from iblock */ 2654 return allocated; 2655 2656 } else if (err) 2657 goto fix_extent_len; 2658 /* 2659 * The depth, and hence eh & ex might change 2660 * as part of the insert above. 2661 */ 2662 newdepth = ext_depth(inode); 2663 /* 2664 * update the extent length after successful insert of the 2665 * split extent 2666 */ 2667 orig_ex.ee_len = cpu_to_le16(ee_len - 2668 ext4_ext_get_actual_len(ex3)); 2669 depth = newdepth; 2670 ext4_ext_drop_refs(path); 2671 path = ext4_ext_find_extent(inode, iblock, path); 2672 if (IS_ERR(path)) { 2673 err = PTR_ERR(path); 2674 goto out; 2675 } 2676 eh = path[depth].p_hdr; 2677 ex = path[depth].p_ext; 2678 if (ex2 != &newex) 2679 ex2 = ex; 2680 2681 err = ext4_ext_get_access(handle, inode, path + depth); 2682 if (err) 2683 goto out; 2684 2685 allocated = max_blocks; 2686 2687 /* If extent has less than EXT4_EXT_ZERO_LEN and we are trying 2688 * to insert a extent in the middle zerout directly 2689 * otherwise give the extent a chance to merge to left 2690 */ 2691 if (le16_to_cpu(orig_ex.ee_len) <= EXT4_EXT_ZERO_LEN && 2692 iblock != ee_block) { 2693 err = ext4_ext_zeroout(inode, &orig_ex); 2694 if (err) 2695 goto fix_extent_len; 2696 /* update the extent length and mark as initialized */ 2697 ex->ee_block = orig_ex.ee_block; 2698 ex->ee_len = orig_ex.ee_len; 2699 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2700 ext4_ext_dirty(handle, inode, path + depth); 2701 /* zero out the first half */ 2702 /* blocks available from iblock */ 2703 return allocated; 2704 } 2705 } 2706 /* 2707 * If there was a change of depth as part of the 2708 * insertion of ex3 above, we need to update the length 2709 * of the ex1 extent again here 2710 */ 2711 if (ex1 && ex1 != ex) { 2712 ex1 = ex; 2713 ex1->ee_len = cpu_to_le16(iblock - ee_block); 2714 ext4_ext_mark_uninitialized(ex1); 2715 ex2 = &newex; 2716 } 2717 /* ex2: iblock to iblock + maxblocks-1 : initialised */ 2718 ex2->ee_block = cpu_to_le32(iblock); 2719 ext4_ext_store_pblock(ex2, newblock); 2720 ex2->ee_len = cpu_to_le16(allocated); 2721 if (ex2 != ex) 2722 goto insert; 2723 /* 2724 * New (initialized) extent starts from the first block 2725 * in the current extent. i.e., ex2 == ex 2726 * We have to see if it can be merged with the extent 2727 * on the left. 2728 */ 2729 if (ex2 > EXT_FIRST_EXTENT(eh)) { 2730 /* 2731 * To merge left, pass "ex2 - 1" to try_to_merge(), 2732 * since it merges towards right _only_. 2733 */ 2734 ret = ext4_ext_try_to_merge(inode, path, ex2 - 1); 2735 if (ret) { 2736 err = ext4_ext_correct_indexes(handle, inode, path); 2737 if (err) 2738 goto out; 2739 depth = ext_depth(inode); 2740 ex2--; 2741 } 2742 } 2743 /* 2744 * Try to Merge towards right. This might be required 2745 * only when the whole extent is being written to. 2746 * i.e. ex2 == ex and ex3 == NULL. 2747 */ 2748 if (!ex3) { 2749 ret = ext4_ext_try_to_merge(inode, path, ex2); 2750 if (ret) { 2751 err = ext4_ext_correct_indexes(handle, inode, path); 2752 if (err) 2753 goto out; 2754 } 2755 } 2756 /* Mark modified extent as dirty */ 2757 err = ext4_ext_dirty(handle, inode, path + depth); 2758 goto out; 2759insert: 2760 err = ext4_ext_insert_extent(handle, inode, path, &newex, 0); 2761 if (err == -ENOSPC) { 2762 err = ext4_ext_zeroout(inode, &orig_ex); 2763 if (err) 2764 goto fix_extent_len; 2765 /* update the extent length and mark as initialized */ 2766 ex->ee_block = orig_ex.ee_block; 2767 ex->ee_len = orig_ex.ee_len; 2768 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2769 ext4_ext_dirty(handle, inode, path + depth); 2770 /* zero out the first half */ 2771 return allocated; 2772 } else if (err) 2773 goto fix_extent_len; 2774out: 2775 ext4_ext_show_leaf(inode, path); 2776 return err ? err : allocated; 2777 2778fix_extent_len: 2779 ex->ee_block = orig_ex.ee_block; 2780 ex->ee_len = orig_ex.ee_len; 2781 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2782 ext4_ext_mark_uninitialized(ex); 2783 ext4_ext_dirty(handle, inode, path + depth); 2784 return err; 2785} 2786 2787/* 2788 * This function is called by ext4_ext_get_blocks() from 2789 * ext4_get_blocks_dio_write() when DIO to write 2790 * to an uninitialized extent. 2791 * 2792 * Writing to an uninitized extent may result in splitting the uninitialized 2793 * extent into multiple /intialized unintialized extents (up to three) 2794 * There are three possibilities: 2795 * a> There is no split required: Entire extent should be uninitialized 2796 * b> Splits in two extents: Write is happening at either end of the extent 2797 * c> Splits in three extents: Somone is writing in middle of the extent 2798 * 2799 * One of more index blocks maybe needed if the extent tree grow after 2800 * the unintialized extent split. To prevent ENOSPC occur at the IO 2801 * complete, we need to split the uninitialized extent before DIO submit 2802 * the IO. The uninitilized extent called at this time will be split 2803 * into three uninitialized extent(at most). After IO complete, the part 2804 * being filled will be convert to initialized by the end_io callback function 2805 * via ext4_convert_unwritten_extents(). 2806 * 2807 * Returns the size of uninitialized extent to be written on success. 2808 */ 2809static int ext4_split_unwritten_extents(handle_t *handle, 2810 struct inode *inode, 2811 struct ext4_ext_path *path, 2812 ext4_lblk_t iblock, 2813 unsigned int max_blocks, 2814 int flags) 2815{ 2816 struct ext4_extent *ex, newex, orig_ex; 2817 struct ext4_extent *ex1 = NULL; 2818 struct ext4_extent *ex2 = NULL; 2819 struct ext4_extent *ex3 = NULL; 2820 struct ext4_extent_header *eh; 2821 ext4_lblk_t ee_block; 2822 unsigned int allocated, ee_len, depth; 2823 ext4_fsblk_t newblock; 2824 int err = 0; 2825 2826 ext_debug("ext4_split_unwritten_extents: inode %lu," 2827 "iblock %llu, max_blocks %u\n", inode->i_ino, 2828 (unsigned long long)iblock, max_blocks); 2829 depth = ext_depth(inode); 2830 eh = path[depth].p_hdr; 2831 ex = path[depth].p_ext; 2832 ee_block = le32_to_cpu(ex->ee_block); 2833 ee_len = ext4_ext_get_actual_len(ex); 2834 allocated = ee_len - (iblock - ee_block); 2835 newblock = iblock - ee_block + ext_pblock(ex); 2836 ex2 = ex; 2837 orig_ex.ee_block = ex->ee_block; 2838 orig_ex.ee_len = cpu_to_le16(ee_len); 2839 ext4_ext_store_pblock(&orig_ex, ext_pblock(ex)); 2840 2841 /* 2842 * If the uninitialized extent begins at the same logical 2843 * block where the write begins, and the write completely 2844 * covers the extent, then we don't need to split it. 2845 */ 2846 if ((iblock == ee_block) && (allocated <= max_blocks)) 2847 return allocated; 2848 2849 err = ext4_ext_get_access(handle, inode, path + depth); 2850 if (err) 2851 goto out; 2852 /* ex1: ee_block to iblock - 1 : uninitialized */ 2853 if (iblock > ee_block) { 2854 ex1 = ex; 2855 ex1->ee_len = cpu_to_le16(iblock - ee_block); 2856 ext4_ext_mark_uninitialized(ex1); 2857 ex2 = &newex; 2858 } 2859 /* 2860 * for sanity, update the length of the ex2 extent before 2861 * we insert ex3, if ex1 is NULL. This is to avoid temporary 2862 * overlap of blocks. 2863 */ 2864 if (!ex1 && allocated > max_blocks) 2865 ex2->ee_len = cpu_to_le16(max_blocks); 2866 /* ex3: to ee_block + ee_len : uninitialised */ 2867 if (allocated > max_blocks) { 2868 unsigned int newdepth; 2869 ex3 = &newex; 2870 ex3->ee_block = cpu_to_le32(iblock + max_blocks); 2871 ext4_ext_store_pblock(ex3, newblock + max_blocks); 2872 ex3->ee_len = cpu_to_le16(allocated - max_blocks); 2873 ext4_ext_mark_uninitialized(ex3); 2874 err = ext4_ext_insert_extent(handle, inode, path, ex3, flags); 2875 if (err == -ENOSPC) { 2876 err = ext4_ext_zeroout(inode, &orig_ex); 2877 if (err) 2878 goto fix_extent_len; 2879 /* update the extent length and mark as initialized */ 2880 ex->ee_block = orig_ex.ee_block; 2881 ex->ee_len = orig_ex.ee_len; 2882 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2883 ext4_ext_dirty(handle, inode, path + depth); 2884 /* zeroed the full extent */ 2885 /* blocks available from iblock */ 2886 return allocated; 2887 2888 } else if (err) 2889 goto fix_extent_len; 2890 /* 2891 * The depth, and hence eh & ex might change 2892 * as part of the insert above. 2893 */ 2894 newdepth = ext_depth(inode); 2895 /* 2896 * update the extent length after successful insert of the 2897 * split extent 2898 */ 2899 orig_ex.ee_len = cpu_to_le16(ee_len - 2900 ext4_ext_get_actual_len(ex3)); 2901 depth = newdepth; 2902 ext4_ext_drop_refs(path); 2903 path = ext4_ext_find_extent(inode, iblock, path); 2904 if (IS_ERR(path)) { 2905 err = PTR_ERR(path); 2906 goto out; 2907 } 2908 eh = path[depth].p_hdr; 2909 ex = path[depth].p_ext; 2910 if (ex2 != &newex) 2911 ex2 = ex; 2912 2913 err = ext4_ext_get_access(handle, inode, path + depth); 2914 if (err) 2915 goto out; 2916 2917 allocated = max_blocks; 2918 } 2919 /* 2920 * If there was a change of depth as part of the 2921 * insertion of ex3 above, we need to update the length 2922 * of the ex1 extent again here 2923 */ 2924 if (ex1 && ex1 != ex) { 2925 ex1 = ex; 2926 ex1->ee_len = cpu_to_le16(iblock - ee_block); 2927 ext4_ext_mark_uninitialized(ex1); 2928 ex2 = &newex; 2929 } 2930 /* 2931 * ex2: iblock to iblock + maxblocks-1 : to be direct IO written, 2932 * uninitialised still. 2933 */ 2934 ex2->ee_block = cpu_to_le32(iblock); 2935 ext4_ext_store_pblock(ex2, newblock); 2936 ex2->ee_len = cpu_to_le16(allocated); 2937 ext4_ext_mark_uninitialized(ex2); 2938 if (ex2 != ex) 2939 goto insert; 2940 /* Mark modified extent as dirty */ 2941 err = ext4_ext_dirty(handle, inode, path + depth); 2942 ext_debug("out here\n"); 2943 goto out; 2944insert: 2945 err = ext4_ext_insert_extent(handle, inode, path, &newex, flags); 2946 if (err == -ENOSPC) { 2947 err = ext4_ext_zeroout(inode, &orig_ex); 2948 if (err) 2949 goto fix_extent_len; 2950 /* update the extent length and mark as initialized */ 2951 ex->ee_block = orig_ex.ee_block; 2952 ex->ee_len = orig_ex.ee_len; 2953 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2954 ext4_ext_dirty(handle, inode, path + depth); 2955 /* zero out the first half */ 2956 return allocated; 2957 } else if (err) 2958 goto fix_extent_len; 2959out: 2960 ext4_ext_show_leaf(inode, path); 2961 return err ? err : allocated; 2962 2963fix_extent_len: 2964 ex->ee_block = orig_ex.ee_block; 2965 ex->ee_len = orig_ex.ee_len; 2966 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2967 ext4_ext_mark_uninitialized(ex); 2968 ext4_ext_dirty(handle, inode, path + depth); 2969 return err; 2970} 2971static int ext4_convert_unwritten_extents_dio(handle_t *handle, 2972 struct inode *inode, 2973 struct ext4_ext_path *path) 2974{ 2975 struct ext4_extent *ex; 2976 struct ext4_extent_header *eh; 2977 int depth; 2978 int err = 0; 2979 int ret = 0; 2980 2981 depth = ext_depth(inode); 2982 eh = path[depth].p_hdr; 2983 ex = path[depth].p_ext; 2984 2985 err = ext4_ext_get_access(handle, inode, path + depth); 2986 if (err) 2987 goto out; 2988 /* first mark the extent as initialized */ 2989 ext4_ext_mark_initialized(ex); 2990 2991 /* 2992 * We have to see if it can be merged with the extent 2993 * on the left. 2994 */ 2995 if (ex > EXT_FIRST_EXTENT(eh)) { 2996 /* 2997 * To merge left, pass "ex - 1" to try_to_merge(), 2998 * since it merges towards right _only_. 2999 */ 3000 ret = ext4_ext_try_to_merge(inode, path, ex - 1); 3001 if (ret) { 3002 err = ext4_ext_correct_indexes(handle, inode, path); 3003 if (err) 3004 goto out; 3005 depth = ext_depth(inode); 3006 ex--; 3007 } 3008 } 3009 /* 3010 * Try to Merge towards right. 3011 */ 3012 ret = ext4_ext_try_to_merge(inode, path, ex); 3013 if (ret) { 3014 err = ext4_ext_correct_indexes(handle, inode, path); 3015 if (err) 3016 goto out; 3017 depth = ext_depth(inode); 3018 } 3019 /* Mark modified extent as dirty */ 3020 err = ext4_ext_dirty(handle, inode, path + depth); 3021out: 3022 ext4_ext_show_leaf(inode, path); 3023 return err; 3024} 3025 3026static void unmap_underlying_metadata_blocks(struct block_device *bdev, 3027 sector_t block, int count) 3028{ 3029 int i; 3030 for (i = 0; i < count; i++) 3031 unmap_underlying_metadata(bdev, block + i); 3032} 3033 3034static int 3035ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode, 3036 ext4_lblk_t iblock, unsigned int max_blocks, 3037 struct ext4_ext_path *path, int flags, 3038 unsigned int allocated, struct buffer_head *bh_result, 3039 ext4_fsblk_t newblock) 3040{ 3041 int ret = 0; 3042 int err = 0; 3043 ext4_io_end_t *io = EXT4_I(inode)->cur_aio_dio; 3044 3045 ext_debug("ext4_ext_handle_uninitialized_extents: inode %lu, logical" 3046 "block %llu, max_blocks %u, flags %d, allocated %u", 3047 inode->i_ino, (unsigned long long)iblock, max_blocks, 3048 flags, allocated); 3049 ext4_ext_show_leaf(inode, path); 3050 3051 /* DIO get_block() before submit the IO, split the extent */ 3052 if (flags == EXT4_GET_BLOCKS_DIO_CREATE_EXT) { 3053 ret = ext4_split_unwritten_extents(handle, 3054 inode, path, iblock, 3055 max_blocks, flags); 3056 /* 3057 * Flag the inode(non aio case) or end_io struct (aio case) 3058 * that this IO needs to convertion to written when IO is 3059 * completed 3060 */ 3061 if (io) 3062 io->flag = DIO_AIO_UNWRITTEN; 3063 else 3064 EXT4_I(inode)->i_state |= EXT4_STATE_DIO_UNWRITTEN; 3065 goto out; 3066 } 3067 /* async DIO end_io complete, convert the filled extent to written */ 3068 if (flags == EXT4_GET_BLOCKS_DIO_CONVERT_EXT) { 3069 ret = ext4_convert_unwritten_extents_dio(handle, inode, 3070 path); 3071 if (ret >= 0) 3072 ext4_update_inode_fsync_trans(handle, inode, 1); 3073 goto out2; 3074 } 3075 /* buffered IO case */ 3076 /* 3077 * repeat fallocate creation request 3078 * we already have an unwritten extent 3079 */ 3080 if (flags & EXT4_GET_BLOCKS_UNINIT_EXT) 3081 goto map_out; 3082 3083 /* buffered READ or buffered write_begin() lookup */ 3084 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) { 3085 /* 3086 * We have blocks reserved already. We 3087 * return allocated blocks so that delalloc 3088 * won't do block reservation for us. But 3089 * the buffer head will be unmapped so that 3090 * a read from the block returns 0s. 3091 */ 3092 set_buffer_unwritten(bh_result); 3093 goto out1; 3094 } 3095 3096 /* buffered write, writepage time, convert*/ 3097 ret = ext4_ext_convert_to_initialized(handle, inode, 3098 path, iblock, 3099 max_blocks); 3100 if (ret >= 0) 3101 ext4_update_inode_fsync_trans(handle, inode, 1); 3102out: 3103 if (ret <= 0) { 3104 err = ret; 3105 goto out2; 3106 } else 3107 allocated = ret; 3108 set_buffer_new(bh_result); 3109 /* 3110 * if we allocated more blocks than requested 3111 * we need to make sure we unmap the extra block 3112 * allocated. The actual needed block will get 3113 * unmapped later when we find the buffer_head marked 3114 * new. 3115 */ 3116 if (allocated > max_blocks) { 3117 unmap_underlying_metadata_blocks(inode->i_sb->s_bdev, 3118 newblock + max_blocks, 3119 allocated - max_blocks); 3120 } 3121map_out: 3122 set_buffer_mapped(bh_result); 3123out1: 3124 if (allocated > max_blocks) 3125 allocated = max_blocks; 3126 ext4_ext_show_leaf(inode, path); 3127 bh_result->b_bdev = inode->i_sb->s_bdev; 3128 bh_result->b_blocknr = newblock; 3129out2: 3130 if (path) { 3131 ext4_ext_drop_refs(path); 3132 kfree(path); 3133 } 3134 return err ? err : allocated; 3135} 3136/* 3137 * Block allocation/map/preallocation routine for extents based files 3138 * 3139 * 3140 * Need to be called with 3141 * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block 3142 * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem) 3143 * 3144 * return > 0, number of of blocks already mapped/allocated 3145 * if create == 0 and these are pre-allocated blocks 3146 * buffer head is unmapped 3147 * otherwise blocks are mapped 3148 * 3149 * return = 0, if plain look up failed (blocks have not been allocated) 3150 * buffer head is unmapped 3151 * 3152 * return < 0, error case. 3153 */ 3154int ext4_ext_get_blocks(handle_t *handle, struct inode *inode, 3155 ext4_lblk_t iblock, 3156 unsigned int max_blocks, struct buffer_head *bh_result, 3157 int flags) 3158{ 3159 struct ext4_ext_path *path = NULL; 3160 struct ext4_extent_header *eh; 3161 struct ext4_extent newex, *ex; 3162 ext4_fsblk_t newblock; 3163 int err = 0, depth, ret, cache_type; 3164 unsigned int allocated = 0; 3165 struct ext4_allocation_request ar; 3166 ext4_io_end_t *io = EXT4_I(inode)->cur_aio_dio; 3167 3168 __clear_bit(BH_New, &bh_result->b_state); 3169 ext_debug("blocks %u/%u requested for inode %lu\n", 3170 iblock, max_blocks, inode->i_ino); 3171 3172 /* check in cache */ 3173 cache_type = ext4_ext_in_cache(inode, iblock, &newex); 3174 if (cache_type) { 3175 if (cache_type == EXT4_EXT_CACHE_GAP) { 3176 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) { 3177 /* 3178 * block isn't allocated yet and 3179 * user doesn't want to allocate it 3180 */ 3181 goto out2; 3182 } 3183 /* we should allocate requested block */ 3184 } else if (cache_type == EXT4_EXT_CACHE_EXTENT) { 3185 /* block is already allocated */ 3186 newblock = iblock 3187 - le32_to_cpu(newex.ee_block) 3188 + ext_pblock(&newex); 3189 /* number of remaining blocks in the extent */ 3190 allocated = ext4_ext_get_actual_len(&newex) - 3191 (iblock - le32_to_cpu(newex.ee_block)); 3192 goto out; 3193 } else { 3194 BUG(); 3195 } 3196 } 3197 3198 /* find extent for this block */ 3199 path = ext4_ext_find_extent(inode, iblock, NULL); 3200 if (IS_ERR(path)) { 3201 err = PTR_ERR(path); 3202 path = NULL; 3203 goto out2; 3204 } 3205 3206 depth = ext_depth(inode); 3207 3208 /* 3209 * consistent leaf must not be empty; 3210 * this situation is possible, though, _during_ tree modification; 3211 * this is why assert can't be put in ext4_ext_find_extent() 3212 */ 3213 if (path[depth].p_ext == NULL && depth != 0) { 3214 ext4_error(inode->i_sb, __func__, "bad extent address " 3215 "inode: %lu, iblock: %d, depth: %d", 3216 inode->i_ino, iblock, depth); 3217 err = -EIO; 3218 goto out2; 3219 } 3220 eh = path[depth].p_hdr; 3221 3222 ex = path[depth].p_ext; 3223 if (ex) { 3224 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block); 3225 ext4_fsblk_t ee_start = ext_pblock(ex); 3226 unsigned short ee_len; 3227 3228 /* 3229 * Uninitialized extents are treated as holes, except that 3230 * we split out initialized portions during a write. 3231 */ 3232 ee_len = ext4_ext_get_actual_len(ex); 3233 /* if found extent covers block, simply return it */ 3234 if (iblock >= ee_block && iblock < ee_block + ee_len) { 3235 newblock = iblock - ee_block + ee_start; 3236 /* number of remaining blocks in the extent */ 3237 allocated = ee_len - (iblock - ee_block); 3238 ext_debug("%u fit into %u:%d -> %llu\n", iblock, 3239 ee_block, ee_len, newblock); 3240 3241 /* Do not put uninitialized extent in the cache */ 3242 if (!ext4_ext_is_uninitialized(ex)) { 3243 ext4_ext_put_in_cache(inode, ee_block, 3244 ee_len, ee_start, 3245 EXT4_EXT_CACHE_EXTENT); 3246 goto out; 3247 } 3248 ret = ext4_ext_handle_uninitialized_extents(handle, 3249 inode, iblock, max_blocks, path, 3250 flags, allocated, bh_result, newblock); 3251 return ret; 3252 } 3253 } 3254 3255 /* 3256 * requested block isn't allocated yet; 3257 * we couldn't try to create block if create flag is zero 3258 */ 3259 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) { 3260 /* 3261 * put just found gap into cache to speed up 3262 * subsequent requests 3263 */ 3264 ext4_ext_put_gap_in_cache(inode, path, iblock); 3265 goto out2; 3266 } 3267 /* 3268 * Okay, we need to do block allocation. 3269 */ 3270 3271 /* find neighbour allocated blocks */ 3272 ar.lleft = iblock; 3273 err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft); 3274 if (err) 3275 goto out2; 3276 ar.lright = iblock; 3277 err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright); 3278 if (err) 3279 goto out2; 3280 3281 /* 3282 * See if request is beyond maximum number of blocks we can have in 3283 * a single extent. For an initialized extent this limit is 3284 * EXT_INIT_MAX_LEN and for an uninitialized extent this limit is 3285 * EXT_UNINIT_MAX_LEN. 3286 */ 3287 if (max_blocks > EXT_INIT_MAX_LEN && 3288 !(flags & EXT4_GET_BLOCKS_UNINIT_EXT)) 3289 max_blocks = EXT_INIT_MAX_LEN; 3290 else if (max_blocks > EXT_UNINIT_MAX_LEN && 3291 (flags & EXT4_GET_BLOCKS_UNINIT_EXT)) 3292 max_blocks = EXT_UNINIT_MAX_LEN; 3293 3294 /* Check if we can really insert (iblock)::(iblock+max_blocks) extent */ 3295 newex.ee_block = cpu_to_le32(iblock); 3296 newex.ee_len = cpu_to_le16(max_blocks); 3297 err = ext4_ext_check_overlap(inode, &newex, path); 3298 if (err) 3299 allocated = ext4_ext_get_actual_len(&newex); 3300 else 3301 allocated = max_blocks; 3302 3303 /* allocate new block */ 3304 ar.inode = inode; 3305 ar.goal = ext4_ext_find_goal(inode, path, iblock); 3306 ar.logical = iblock; 3307 ar.len = allocated; 3308 if (S_ISREG(inode->i_mode)) 3309 ar.flags = EXT4_MB_HINT_DATA; 3310 else 3311 /* disable in-core preallocation for non-regular files */ 3312 ar.flags = 0; 3313 newblock = ext4_mb_new_blocks(handle, &ar, &err); 3314 if (!newblock) 3315 goto out2; 3316 ext_debug("allocate new block: goal %llu, found %llu/%u\n", 3317 ar.goal, newblock, allocated); 3318 3319 /* try to insert new extent into found leaf and return */ 3320 ext4_ext_store_pblock(&newex, newblock); 3321 newex.ee_len = cpu_to_le16(ar.len); 3322 /* Mark uninitialized */ 3323 if (flags & EXT4_GET_BLOCKS_UNINIT_EXT){ 3324 ext4_ext_mark_uninitialized(&newex); 3325 /* 3326 * io_end structure was created for every async 3327 * direct IO write to the middle of the file. 3328 * To avoid unecessary convertion for every aio dio rewrite 3329 * to the mid of file, here we flag the IO that is really 3330 * need the convertion. 3331 * For non asycn direct IO case, flag the inode state 3332 * that we need to perform convertion when IO is done. 3333 */ 3334 if (flags == EXT4_GET_BLOCKS_DIO_CREATE_EXT) { 3335 if (io) 3336 io->flag = DIO_AIO_UNWRITTEN; 3337 else 3338 EXT4_I(inode)->i_state |= 3339 EXT4_STATE_DIO_UNWRITTEN;; 3340 } 3341 } 3342 err = ext4_ext_insert_extent(handle, inode, path, &newex, flags); 3343 if (err) { 3344 /* free data blocks we just allocated */ 3345 /* not a good idea to call discard here directly, 3346 * but otherwise we'd need to call it every free() */ 3347 ext4_discard_preallocations(inode); 3348 ext4_free_blocks(handle, inode, 0, ext_pblock(&newex), 3349 ext4_ext_get_actual_len(&newex), 0); 3350 goto out2; 3351 } 3352 3353 /* previous routine could use block we allocated */ 3354 newblock = ext_pblock(&newex); 3355 allocated = ext4_ext_get_actual_len(&newex); 3356 set_buffer_new(bh_result); 3357 3358 /* 3359 * Cache the extent and update transaction to commit on fdatasync only 3360 * when it is _not_ an uninitialized extent. 3361 */ 3362 if ((flags & EXT4_GET_BLOCKS_UNINIT_EXT) == 0) { 3363 ext4_ext_put_in_cache(inode, iblock, allocated, newblock, 3364 EXT4_EXT_CACHE_EXTENT); 3365 ext4_update_inode_fsync_trans(handle, inode, 1); 3366 } else 3367 ext4_update_inode_fsync_trans(handle, inode, 0); 3368out: 3369 if (allocated > max_blocks) 3370 allocated = max_blocks; 3371 ext4_ext_show_leaf(inode, path); 3372 set_buffer_mapped(bh_result); 3373 bh_result->b_bdev = inode->i_sb->s_bdev; 3374 bh_result->b_blocknr = newblock; 3375out2: 3376 if (path) { 3377 ext4_ext_drop_refs(path); 3378 kfree(path); 3379 } 3380 return err ? err : allocated; 3381} 3382 3383void ext4_ext_truncate(struct inode *inode) 3384{ 3385 struct address_space *mapping = inode->i_mapping; 3386 struct super_block *sb = inode->i_sb; 3387 ext4_lblk_t last_block; 3388 handle_t *handle; 3389 int err = 0; 3390 3391 /* 3392 * probably first extent we're gonna free will be last in block 3393 */ 3394 err = ext4_writepage_trans_blocks(inode); 3395 handle = ext4_journal_start(inode, err); 3396 if (IS_ERR(handle)) 3397 return; 3398 3399 if (inode->i_size & (sb->s_blocksize - 1)) 3400 ext4_block_truncate_page(handle, mapping, inode->i_size); 3401 3402 if (ext4_orphan_add(handle, inode)) 3403 goto out_stop; 3404 3405 down_write(&EXT4_I(inode)->i_data_sem); 3406 ext4_ext_invalidate_cache(inode); 3407 3408 ext4_discard_preallocations(inode); 3409 3410 /* 3411 * TODO: optimization is possible here. 3412 * Probably we need not scan at all, 3413 * because page truncation is enough. 3414 */ 3415 3416 /* we have to know where to truncate from in crash case */ 3417 EXT4_I(inode)->i_disksize = inode->i_size; 3418 ext4_mark_inode_dirty(handle, inode); 3419 3420 last_block = (inode->i_size + sb->s_blocksize - 1) 3421 >> EXT4_BLOCK_SIZE_BITS(sb); 3422 err = ext4_ext_remove_space(inode, last_block); 3423 3424 /* In a multi-transaction truncate, we only make the final 3425 * transaction synchronous. 3426 */ 3427 if (IS_SYNC(inode)) 3428 ext4_handle_sync(handle); 3429 3430out_stop: 3431 up_write(&EXT4_I(inode)->i_data_sem); 3432 /* 3433 * If this was a simple ftruncate() and the file will remain alive, 3434 * then we need to clear up the orphan record which we created above. 3435 * However, if this was a real unlink then we were called by 3436 * ext4_delete_inode(), and we allow that function to clean up the 3437 * orphan info for us. 3438 */ 3439 if (inode->i_nlink) 3440 ext4_orphan_del(handle, inode); 3441 3442 inode->i_mtime = inode->i_ctime = ext4_current_time(inode); 3443 ext4_mark_inode_dirty(handle, inode); 3444 ext4_journal_stop(handle); 3445} 3446 3447static void ext4_falloc_update_inode(struct inode *inode, 3448 int mode, loff_t new_size, int update_ctime) 3449{ 3450 struct timespec now; 3451 3452 if (update_ctime) { 3453 now = current_fs_time(inode->i_sb); 3454 if (!timespec_equal(&inode->i_ctime, &now)) 3455 inode->i_ctime = now; 3456 } 3457 /* 3458 * Update only when preallocation was requested beyond 3459 * the file size. 3460 */ 3461 if (!(mode & FALLOC_FL_KEEP_SIZE)) { 3462 if (new_size > i_size_read(inode)) 3463 i_size_write(inode, new_size); 3464 if (new_size > EXT4_I(inode)->i_disksize) 3465 ext4_update_i_disksize(inode, new_size); 3466 } 3467 3468} 3469 3470/* 3471 * preallocate space for a file. This implements ext4's fallocate inode 3472 * operation, which gets called from sys_fallocate system call. 3473 * For block-mapped files, posix_fallocate should fall back to the method 3474 * of writing zeroes to the required new blocks (the same behavior which is 3475 * expected for file systems which do not support fallocate() system call). 3476 */ 3477long ext4_fallocate(struct inode *inode, int mode, loff_t offset, loff_t len) 3478{ 3479 handle_t *handle; 3480 ext4_lblk_t block; 3481 loff_t new_size; 3482 unsigned int max_blocks; 3483 int ret = 0; 3484 int ret2 = 0; 3485 int retries = 0; 3486 struct buffer_head map_bh; 3487 unsigned int credits, blkbits = inode->i_blkbits; 3488 3489 /* 3490 * currently supporting (pre)allocate mode for extent-based 3491 * files _only_ 3492 */ 3493 if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) 3494 return -EOPNOTSUPP; 3495 3496 /* preallocation to directories is currently not supported */ 3497 if (S_ISDIR(inode->i_mode)) 3498 return -ENODEV; 3499 3500 block = offset >> blkbits; 3501 /* 3502 * We can't just convert len to max_blocks because 3503 * If blocksize = 4096 offset = 3072 and len = 2048 3504 */ 3505 max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits) 3506 - block; 3507 /* 3508 * credits to insert 1 extent into extent tree 3509 */ 3510 credits = ext4_chunk_trans_blocks(inode, max_blocks); 3511 mutex_lock(&inode->i_mutex); 3512retry: 3513 while (ret >= 0 && ret < max_blocks) { 3514 block = block + ret; 3515 max_blocks = max_blocks - ret; 3516 handle = ext4_journal_start(inode, credits); 3517 if (IS_ERR(handle)) { 3518 ret = PTR_ERR(handle); 3519 break; 3520 } 3521 map_bh.b_state = 0; 3522 ret = ext4_get_blocks(handle, inode, block, 3523 max_blocks, &map_bh, 3524 EXT4_GET_BLOCKS_CREATE_UNINIT_EXT); 3525 if (ret <= 0) { 3526#ifdef EXT4FS_DEBUG 3527 WARN_ON(ret <= 0); 3528 printk(KERN_ERR "%s: ext4_ext_get_blocks " 3529 "returned error inode#%lu, block=%u, " 3530 "max_blocks=%u", __func__, 3531 inode->i_ino, block, max_blocks); 3532#endif 3533 ext4_mark_inode_dirty(handle, inode); 3534 ret2 = ext4_journal_stop(handle); 3535 break; 3536 } 3537 if ((block + ret) >= (EXT4_BLOCK_ALIGN(offset + len, 3538 blkbits) >> blkbits)) 3539 new_size = offset + len; 3540 else 3541 new_size = (block + ret) << blkbits; 3542 3543 ext4_falloc_update_inode(inode, mode, new_size, 3544 buffer_new(&map_bh)); 3545 ext4_mark_inode_dirty(handle, inode); 3546 ret2 = ext4_journal_stop(handle); 3547 if (ret2) 3548 break; 3549 } 3550 if (ret == -ENOSPC && 3551 ext4_should_retry_alloc(inode->i_sb, &retries)) { 3552 ret = 0; 3553 goto retry; 3554 } 3555 mutex_unlock(&inode->i_mutex); 3556 return ret > 0 ? ret2 : ret; 3557} 3558 3559/* 3560 * This function convert a range of blocks to written extents 3561 * The caller of this function will pass the start offset and the size. 3562 * all unwritten extents within this range will be converted to 3563 * written extents. 3564 * 3565 * This function is called from the direct IO end io call back 3566 * function, to convert the fallocated extents after IO is completed. 3567 * Returns 0 on success. 3568 */ 3569int ext4_convert_unwritten_extents(struct inode *inode, loff_t offset, 3570 loff_t len) 3571{ 3572 handle_t *handle; 3573 ext4_lblk_t block; 3574 unsigned int max_blocks; 3575 int ret = 0; 3576 int ret2 = 0; 3577 struct buffer_head map_bh; 3578 unsigned int credits, blkbits = inode->i_blkbits; 3579 3580 block = offset >> blkbits; 3581 /* 3582 * We can't just convert len to max_blocks because 3583 * If blocksize = 4096 offset = 3072 and len = 2048 3584 */ 3585 max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits) 3586 - block; 3587 /* 3588 * credits to insert 1 extent into extent tree 3589 */ 3590 credits = ext4_chunk_trans_blocks(inode, max_blocks); 3591 while (ret >= 0 && ret < max_blocks) { 3592 block = block + ret; 3593 max_blocks = max_blocks - ret; 3594 handle = ext4_journal_start(inode, credits); 3595 if (IS_ERR(handle)) { 3596 ret = PTR_ERR(handle); 3597 break; 3598 } 3599 map_bh.b_state = 0; 3600 ret = ext4_get_blocks(handle, inode, block, 3601 max_blocks, &map_bh, 3602 EXT4_GET_BLOCKS_DIO_CONVERT_EXT); 3603 if (ret <= 0) { 3604 WARN_ON(ret <= 0); 3605 printk(KERN_ERR "%s: ext4_ext_get_blocks " 3606 "returned error inode#%lu, block=%u, " 3607 "max_blocks=%u", __func__, 3608 inode->i_ino, block, max_blocks); 3609 } 3610 ext4_mark_inode_dirty(handle, inode); 3611 ret2 = ext4_journal_stop(handle); 3612 if (ret <= 0 || ret2 ) 3613 break; 3614 } 3615 return ret > 0 ? ret2 : ret; 3616} 3617/* 3618 * Callback function called for each extent to gather FIEMAP information. 3619 */ 3620static int ext4_ext_fiemap_cb(struct inode *inode, struct ext4_ext_path *path, 3621 struct ext4_ext_cache *newex, struct ext4_extent *ex, 3622 void *data) 3623{ 3624 struct fiemap_extent_info *fieinfo = data; 3625 unsigned char blksize_bits = inode->i_sb->s_blocksize_bits; 3626 __u64 logical; 3627 __u64 physical; 3628 __u64 length; 3629 __u32 flags = 0; 3630 int error; 3631 3632 logical = (__u64)newex->ec_block << blksize_bits; 3633 3634 if (newex->ec_type == EXT4_EXT_CACHE_GAP) { 3635 pgoff_t offset; 3636 struct page *page; 3637 struct buffer_head *bh = NULL; 3638 3639 offset = logical >> PAGE_SHIFT; 3640 page = find_get_page(inode->i_mapping, offset); 3641 if (!page || !page_has_buffers(page)) 3642 return EXT_CONTINUE; 3643 3644 bh = page_buffers(page); 3645 3646 if (!bh) 3647 return EXT_CONTINUE; 3648 3649 if (buffer_delay(bh)) { 3650 flags |= FIEMAP_EXTENT_DELALLOC; 3651 page_cache_release(page); 3652 } else { 3653 page_cache_release(page); 3654 return EXT_CONTINUE; 3655 } 3656 } 3657 3658 physical = (__u64)newex->ec_start << blksize_bits; 3659 length = (__u64)newex->ec_len << blksize_bits; 3660 3661 if (ex && ext4_ext_is_uninitialized(ex)) 3662 flags |= FIEMAP_EXTENT_UNWRITTEN; 3663 3664 /* 3665 * If this extent reaches EXT_MAX_BLOCK, it must be last. 3666 * 3667 * Or if ext4_ext_next_allocated_block is EXT_MAX_BLOCK, 3668 * this also indicates no more allocated blocks. 3669 * 3670 * XXX this might miss a single-block extent at EXT_MAX_BLOCK 3671 */ 3672 if (ext4_ext_next_allocated_block(path) == EXT_MAX_BLOCK || 3673 newex->ec_block + newex->ec_len - 1 == EXT_MAX_BLOCK) { 3674 loff_t size = i_size_read(inode); 3675 loff_t bs = EXT4_BLOCK_SIZE(inode->i_sb); 3676 3677 flags |= FIEMAP_EXTENT_LAST; 3678 if ((flags & FIEMAP_EXTENT_DELALLOC) && 3679 logical+length > size) 3680 length = (size - logical + bs - 1) & ~(bs-1); 3681 } 3682 3683 error = fiemap_fill_next_extent(fieinfo, logical, physical, 3684 length, flags); 3685 if (error < 0) 3686 return error; 3687 if (error == 1) 3688 return EXT_BREAK; 3689 3690 return EXT_CONTINUE; 3691} 3692 3693/* fiemap flags we can handle specified here */ 3694#define EXT4_FIEMAP_FLAGS (FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR) 3695 3696static int ext4_xattr_fiemap(struct inode *inode, 3697 struct fiemap_extent_info *fieinfo) 3698{ 3699 __u64 physical = 0; 3700 __u64 length; 3701 __u32 flags = FIEMAP_EXTENT_LAST; 3702 int blockbits = inode->i_sb->s_blocksize_bits; 3703 int error = 0; 3704 3705 /* in-inode? */ 3706 if (EXT4_I(inode)->i_state & EXT4_STATE_XATTR) { 3707 struct ext4_iloc iloc; 3708 int offset; /* offset of xattr in inode */ 3709 3710 error = ext4_get_inode_loc(inode, &iloc); 3711 if (error) 3712 return error; 3713 physical = iloc.bh->b_blocknr << blockbits; 3714 offset = EXT4_GOOD_OLD_INODE_SIZE + 3715 EXT4_I(inode)->i_extra_isize; 3716 physical += offset; 3717 length = EXT4_SB(inode->i_sb)->s_inode_size - offset; 3718 flags |= FIEMAP_EXTENT_DATA_INLINE; 3719 } else { /* external block */ 3720 physical = EXT4_I(inode)->i_file_acl << blockbits; 3721 length = inode->i_sb->s_blocksize; 3722 } 3723 3724 if (physical) 3725 error = fiemap_fill_next_extent(fieinfo, 0, physical, 3726 length, flags); 3727 return (error < 0 ? error : 0); 3728} 3729 3730int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, 3731 __u64 start, __u64 len) 3732{ 3733 ext4_lblk_t start_blk; 3734 ext4_lblk_t len_blks; 3735 int error = 0; 3736 3737 /* fallback to generic here if not in extents fmt */ 3738 if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) 3739 return generic_block_fiemap(inode, fieinfo, start, len, 3740 ext4_get_block); 3741 3742 if (fiemap_check_flags(fieinfo, EXT4_FIEMAP_FLAGS)) 3743 return -EBADR; 3744 3745 if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) { 3746 error = ext4_xattr_fiemap(inode, fieinfo); 3747 } else { 3748 start_blk = start >> inode->i_sb->s_blocksize_bits; 3749 len_blks = len >> inode->i_sb->s_blocksize_bits; 3750 3751 /* 3752 * Walk the extent tree gathering extent information. 3753 * ext4_ext_fiemap_cb will push extents back to user. 3754 */ 3755 error = ext4_ext_walk_space(inode, start_blk, len_blks, 3756 ext4_ext_fiemap_cb, fieinfo); 3757 } 3758 3759 return error; 3760} 3761 3762