extents.c revision 9fd9784c91db79e953ea3fe3741f885bdc390a72
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 */ 52static ext4_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_journal_restart(handle_t *handle, int needed) 97{ 98 int err; 99 100 if (!ext4_handle_valid(handle)) 101 return 0; 102 if (handle->h_buffer_credits > needed) 103 return 0; 104 err = ext4_journal_extend(handle, needed); 105 if (err <= 0) 106 return err; 107 return ext4_journal_restart(handle, needed); 108} 109 110/* 111 * could return: 112 * - EROFS 113 * - ENOMEM 114 */ 115static int ext4_ext_get_access(handle_t *handle, struct inode *inode, 116 struct ext4_ext_path *path) 117{ 118 if (path->p_bh) { 119 /* path points to block */ 120 return ext4_journal_get_write_access(handle, path->p_bh); 121 } 122 /* path points to leaf/index in inode body */ 123 /* we use in-core data, no need to protect them */ 124 return 0; 125} 126 127/* 128 * could return: 129 * - EROFS 130 * - ENOMEM 131 * - EIO 132 */ 133static int ext4_ext_dirty(handle_t *handle, struct inode *inode, 134 struct ext4_ext_path *path) 135{ 136 int err; 137 if (path->p_bh) { 138 /* path points to block */ 139 err = ext4_handle_dirty_metadata(handle, inode, path->p_bh); 140 } else { 141 /* path points to leaf/index in inode body */ 142 err = ext4_mark_inode_dirty(handle, inode); 143 } 144 return err; 145} 146 147static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode, 148 struct ext4_ext_path *path, 149 ext4_lblk_t block) 150{ 151 struct ext4_inode_info *ei = EXT4_I(inode); 152 ext4_fsblk_t bg_start; 153 ext4_fsblk_t last_block; 154 ext4_grpblk_t colour; 155 int depth; 156 157 if (path) { 158 struct ext4_extent *ex; 159 depth = path->p_depth; 160 161 /* try to predict block placement */ 162 ex = path[depth].p_ext; 163 if (ex) 164 return ext_pblock(ex)+(block-le32_to_cpu(ex->ee_block)); 165 166 /* it looks like index is empty; 167 * try to find starting block from index itself */ 168 if (path[depth].p_bh) 169 return path[depth].p_bh->b_blocknr; 170 } 171 172 /* OK. use inode's group */ 173 bg_start = (ei->i_block_group * EXT4_BLOCKS_PER_GROUP(inode->i_sb)) + 174 le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_first_data_block); 175 last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1; 176 177 if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block) 178 colour = (current->pid % 16) * 179 (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16); 180 else 181 colour = (current->pid % 16) * ((last_block - bg_start) / 16); 182 return bg_start + colour + block; 183} 184 185/* 186 * Allocation for a meta data block 187 */ 188static ext4_fsblk_t 189ext4_ext_new_meta_block(handle_t *handle, struct inode *inode, 190 struct ext4_ext_path *path, 191 struct ext4_extent *ex, int *err) 192{ 193 ext4_fsblk_t goal, newblock; 194 195 goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block)); 196 newblock = ext4_new_meta_blocks(handle, inode, goal, NULL, err); 197 return newblock; 198} 199 200static int ext4_ext_space_block(struct inode *inode) 201{ 202 int size; 203 204 size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header)) 205 / sizeof(struct ext4_extent); 206#ifdef AGGRESSIVE_TEST 207 if (size > 6) 208 size = 6; 209#endif 210 return size; 211} 212 213static int ext4_ext_space_block_idx(struct inode *inode) 214{ 215 int size; 216 217 size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header)) 218 / sizeof(struct ext4_extent_idx); 219#ifdef AGGRESSIVE_TEST 220 if (size > 5) 221 size = 5; 222#endif 223 return size; 224} 225 226static int ext4_ext_space_root(struct inode *inode) 227{ 228 int size; 229 230 size = sizeof(EXT4_I(inode)->i_data); 231 size -= sizeof(struct ext4_extent_header); 232 size /= sizeof(struct ext4_extent); 233#ifdef AGGRESSIVE_TEST 234 if (size > 3) 235 size = 3; 236#endif 237 return size; 238} 239 240static int ext4_ext_space_root_idx(struct inode *inode) 241{ 242 int size; 243 244 size = sizeof(EXT4_I(inode)->i_data); 245 size -= sizeof(struct ext4_extent_header); 246 size /= sizeof(struct ext4_extent_idx); 247#ifdef AGGRESSIVE_TEST 248 if (size > 4) 249 size = 4; 250#endif 251 return size; 252} 253 254/* 255 * Calculate the number of metadata blocks needed 256 * to allocate @blocks 257 * Worse case is one block per extent 258 */ 259int ext4_ext_calc_metadata_amount(struct inode *inode, int blocks) 260{ 261 int lcap, icap, rcap, leafs, idxs, num; 262 int newextents = blocks; 263 264 rcap = ext4_ext_space_root_idx(inode); 265 lcap = ext4_ext_space_block(inode); 266 icap = ext4_ext_space_block_idx(inode); 267 268 /* number of new leaf blocks needed */ 269 num = leafs = (newextents + lcap - 1) / lcap; 270 271 /* 272 * Worse case, we need separate index block(s) 273 * to link all new leaf blocks 274 */ 275 idxs = (leafs + icap - 1) / icap; 276 do { 277 num += idxs; 278 idxs = (idxs + icap - 1) / icap; 279 } while (idxs > rcap); 280 281 return num; 282} 283 284static int 285ext4_ext_max_entries(struct inode *inode, int depth) 286{ 287 int max; 288 289 if (depth == ext_depth(inode)) { 290 if (depth == 0) 291 max = ext4_ext_space_root(inode); 292 else 293 max = ext4_ext_space_root_idx(inode); 294 } else { 295 if (depth == 0) 296 max = ext4_ext_space_block(inode); 297 else 298 max = ext4_ext_space_block_idx(inode); 299 } 300 301 return max; 302} 303 304static int __ext4_ext_check_header(const char *function, struct inode *inode, 305 struct ext4_extent_header *eh, 306 int depth) 307{ 308 const char *error_msg; 309 int max = 0; 310 311 if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) { 312 error_msg = "invalid magic"; 313 goto corrupted; 314 } 315 if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) { 316 error_msg = "unexpected eh_depth"; 317 goto corrupted; 318 } 319 if (unlikely(eh->eh_max == 0)) { 320 error_msg = "invalid eh_max"; 321 goto corrupted; 322 } 323 max = ext4_ext_max_entries(inode, depth); 324 if (unlikely(le16_to_cpu(eh->eh_max) > max)) { 325 error_msg = "too large eh_max"; 326 goto corrupted; 327 } 328 if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) { 329 error_msg = "invalid eh_entries"; 330 goto corrupted; 331 } 332 return 0; 333 334corrupted: 335 ext4_error(inode->i_sb, function, 336 "bad header in inode #%lu: %s - magic %x, " 337 "entries %u, max %u(%u), depth %u(%u)", 338 inode->i_ino, error_msg, le16_to_cpu(eh->eh_magic), 339 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max), 340 max, le16_to_cpu(eh->eh_depth), depth); 341 342 return -EIO; 343} 344 345#define ext4_ext_check_header(inode, eh, depth) \ 346 __ext4_ext_check_header(__func__, inode, eh, depth) 347 348#ifdef EXT_DEBUG 349static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path) 350{ 351 int k, l = path->p_depth; 352 353 ext_debug("path:"); 354 for (k = 0; k <= l; k++, path++) { 355 if (path->p_idx) { 356 ext_debug(" %d->%llu", le32_to_cpu(path->p_idx->ei_block), 357 idx_pblock(path->p_idx)); 358 } else if (path->p_ext) { 359 ext_debug(" %d:%d:%llu ", 360 le32_to_cpu(path->p_ext->ee_block), 361 ext4_ext_get_actual_len(path->p_ext), 362 ext_pblock(path->p_ext)); 363 } else 364 ext_debug(" []"); 365 } 366 ext_debug("\n"); 367} 368 369static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path) 370{ 371 int depth = ext_depth(inode); 372 struct ext4_extent_header *eh; 373 struct ext4_extent *ex; 374 int i; 375 376 if (!path) 377 return; 378 379 eh = path[depth].p_hdr; 380 ex = EXT_FIRST_EXTENT(eh); 381 382 for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) { 383 ext_debug("%d:%d:%llu ", le32_to_cpu(ex->ee_block), 384 ext4_ext_get_actual_len(ex), ext_pblock(ex)); 385 } 386 ext_debug("\n"); 387} 388#else 389#define ext4_ext_show_path(inode, path) 390#define ext4_ext_show_leaf(inode, path) 391#endif 392 393void ext4_ext_drop_refs(struct ext4_ext_path *path) 394{ 395 int depth = path->p_depth; 396 int i; 397 398 for (i = 0; i <= depth; i++, path++) 399 if (path->p_bh) { 400 brelse(path->p_bh); 401 path->p_bh = NULL; 402 } 403} 404 405/* 406 * ext4_ext_binsearch_idx: 407 * binary search for the closest index of the given block 408 * the header must be checked before calling this 409 */ 410static void 411ext4_ext_binsearch_idx(struct inode *inode, 412 struct ext4_ext_path *path, ext4_lblk_t block) 413{ 414 struct ext4_extent_header *eh = path->p_hdr; 415 struct ext4_extent_idx *r, *l, *m; 416 417 418 ext_debug("binsearch for %u(idx): ", block); 419 420 l = EXT_FIRST_INDEX(eh) + 1; 421 r = EXT_LAST_INDEX(eh); 422 while (l <= r) { 423 m = l + (r - l) / 2; 424 if (block < le32_to_cpu(m->ei_block)) 425 r = m - 1; 426 else 427 l = m + 1; 428 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ei_block), 429 m, le32_to_cpu(m->ei_block), 430 r, le32_to_cpu(r->ei_block)); 431 } 432 433 path->p_idx = l - 1; 434 ext_debug(" -> %d->%lld ", le32_to_cpu(path->p_idx->ei_block), 435 idx_pblock(path->p_idx)); 436 437#ifdef CHECK_BINSEARCH 438 { 439 struct ext4_extent_idx *chix, *ix; 440 int k; 441 442 chix = ix = EXT_FIRST_INDEX(eh); 443 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) { 444 if (k != 0 && 445 le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) { 446 printk(KERN_DEBUG "k=%d, ix=0x%p, " 447 "first=0x%p\n", k, 448 ix, EXT_FIRST_INDEX(eh)); 449 printk(KERN_DEBUG "%u <= %u\n", 450 le32_to_cpu(ix->ei_block), 451 le32_to_cpu(ix[-1].ei_block)); 452 } 453 BUG_ON(k && le32_to_cpu(ix->ei_block) 454 <= le32_to_cpu(ix[-1].ei_block)); 455 if (block < le32_to_cpu(ix->ei_block)) 456 break; 457 chix = ix; 458 } 459 BUG_ON(chix != path->p_idx); 460 } 461#endif 462 463} 464 465/* 466 * ext4_ext_binsearch: 467 * binary search for closest extent of the given block 468 * the header must be checked before calling this 469 */ 470static void 471ext4_ext_binsearch(struct inode *inode, 472 struct ext4_ext_path *path, ext4_lblk_t block) 473{ 474 struct ext4_extent_header *eh = path->p_hdr; 475 struct ext4_extent *r, *l, *m; 476 477 if (eh->eh_entries == 0) { 478 /* 479 * this leaf is empty: 480 * we get such a leaf in split/add case 481 */ 482 return; 483 } 484 485 ext_debug("binsearch for %u: ", block); 486 487 l = EXT_FIRST_EXTENT(eh) + 1; 488 r = EXT_LAST_EXTENT(eh); 489 490 while (l <= r) { 491 m = l + (r - l) / 2; 492 if (block < le32_to_cpu(m->ee_block)) 493 r = m - 1; 494 else 495 l = m + 1; 496 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ee_block), 497 m, le32_to_cpu(m->ee_block), 498 r, le32_to_cpu(r->ee_block)); 499 } 500 501 path->p_ext = l - 1; 502 ext_debug(" -> %d:%llu:%d ", 503 le32_to_cpu(path->p_ext->ee_block), 504 ext_pblock(path->p_ext), 505 ext4_ext_get_actual_len(path->p_ext)); 506 507#ifdef CHECK_BINSEARCH 508 { 509 struct ext4_extent *chex, *ex; 510 int k; 511 512 chex = ex = EXT_FIRST_EXTENT(eh); 513 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) { 514 BUG_ON(k && le32_to_cpu(ex->ee_block) 515 <= le32_to_cpu(ex[-1].ee_block)); 516 if (block < le32_to_cpu(ex->ee_block)) 517 break; 518 chex = ex; 519 } 520 BUG_ON(chex != path->p_ext); 521 } 522#endif 523 524} 525 526int ext4_ext_tree_init(handle_t *handle, struct inode *inode) 527{ 528 struct ext4_extent_header *eh; 529 530 eh = ext_inode_hdr(inode); 531 eh->eh_depth = 0; 532 eh->eh_entries = 0; 533 eh->eh_magic = EXT4_EXT_MAGIC; 534 eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode)); 535 ext4_mark_inode_dirty(handle, inode); 536 ext4_ext_invalidate_cache(inode); 537 return 0; 538} 539 540struct ext4_ext_path * 541ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block, 542 struct ext4_ext_path *path) 543{ 544 struct ext4_extent_header *eh; 545 struct buffer_head *bh; 546 short int depth, i, ppos = 0, alloc = 0; 547 548 eh = ext_inode_hdr(inode); 549 depth = ext_depth(inode); 550 if (ext4_ext_check_header(inode, eh, depth)) 551 return ERR_PTR(-EIO); 552 553 554 /* account possible depth increase */ 555 if (!path) { 556 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2), 557 GFP_NOFS); 558 if (!path) 559 return ERR_PTR(-ENOMEM); 560 alloc = 1; 561 } 562 path[0].p_hdr = eh; 563 path[0].p_bh = NULL; 564 565 i = depth; 566 /* walk through the tree */ 567 while (i) { 568 ext_debug("depth %d: num %d, max %d\n", 569 ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max)); 570 571 ext4_ext_binsearch_idx(inode, path + ppos, block); 572 path[ppos].p_block = idx_pblock(path[ppos].p_idx); 573 path[ppos].p_depth = i; 574 path[ppos].p_ext = NULL; 575 576 bh = sb_bread(inode->i_sb, path[ppos].p_block); 577 if (!bh) 578 goto err; 579 580 eh = ext_block_hdr(bh); 581 ppos++; 582 BUG_ON(ppos > depth); 583 path[ppos].p_bh = bh; 584 path[ppos].p_hdr = eh; 585 i--; 586 587 if (ext4_ext_check_header(inode, eh, i)) 588 goto err; 589 } 590 591 path[ppos].p_depth = i; 592 path[ppos].p_ext = NULL; 593 path[ppos].p_idx = NULL; 594 595 /* find extent */ 596 ext4_ext_binsearch(inode, path + ppos, block); 597 /* if not an empty leaf */ 598 if (path[ppos].p_ext) 599 path[ppos].p_block = ext_pblock(path[ppos].p_ext); 600 601 ext4_ext_show_path(inode, path); 602 603 return path; 604 605err: 606 ext4_ext_drop_refs(path); 607 if (alloc) 608 kfree(path); 609 return ERR_PTR(-EIO); 610} 611 612/* 613 * ext4_ext_insert_index: 614 * insert new index [@logical;@ptr] into the block at @curp; 615 * check where to insert: before @curp or after @curp 616 */ 617static int ext4_ext_insert_index(handle_t *handle, struct inode *inode, 618 struct ext4_ext_path *curp, 619 int logical, ext4_fsblk_t ptr) 620{ 621 struct ext4_extent_idx *ix; 622 int len, err; 623 624 err = ext4_ext_get_access(handle, inode, curp); 625 if (err) 626 return err; 627 628 BUG_ON(logical == le32_to_cpu(curp->p_idx->ei_block)); 629 len = EXT_MAX_INDEX(curp->p_hdr) - curp->p_idx; 630 if (logical > le32_to_cpu(curp->p_idx->ei_block)) { 631 /* insert after */ 632 if (curp->p_idx != EXT_LAST_INDEX(curp->p_hdr)) { 633 len = (len - 1) * sizeof(struct ext4_extent_idx); 634 len = len < 0 ? 0 : len; 635 ext_debug("insert new index %d after: %llu. " 636 "move %d from 0x%p to 0x%p\n", 637 logical, ptr, len, 638 (curp->p_idx + 1), (curp->p_idx + 2)); 639 memmove(curp->p_idx + 2, curp->p_idx + 1, len); 640 } 641 ix = curp->p_idx + 1; 642 } else { 643 /* insert before */ 644 len = len * sizeof(struct ext4_extent_idx); 645 len = len < 0 ? 0 : len; 646 ext_debug("insert new index %d before: %llu. " 647 "move %d from 0x%p to 0x%p\n", 648 logical, ptr, len, 649 curp->p_idx, (curp->p_idx + 1)); 650 memmove(curp->p_idx + 1, curp->p_idx, len); 651 ix = curp->p_idx; 652 } 653 654 ix->ei_block = cpu_to_le32(logical); 655 ext4_idx_store_pblock(ix, ptr); 656 le16_add_cpu(&curp->p_hdr->eh_entries, 1); 657 658 BUG_ON(le16_to_cpu(curp->p_hdr->eh_entries) 659 > le16_to_cpu(curp->p_hdr->eh_max)); 660 BUG_ON(ix > EXT_LAST_INDEX(curp->p_hdr)); 661 662 err = ext4_ext_dirty(handle, inode, curp); 663 ext4_std_error(inode->i_sb, err); 664 665 return err; 666} 667 668/* 669 * ext4_ext_split: 670 * inserts new subtree into the path, using free index entry 671 * at depth @at: 672 * - allocates all needed blocks (new leaf and all intermediate index blocks) 673 * - makes decision where to split 674 * - moves remaining extents and index entries (right to the split point) 675 * into the newly allocated blocks 676 * - initializes subtree 677 */ 678static int ext4_ext_split(handle_t *handle, struct inode *inode, 679 struct ext4_ext_path *path, 680 struct ext4_extent *newext, int at) 681{ 682 struct buffer_head *bh = NULL; 683 int depth = ext_depth(inode); 684 struct ext4_extent_header *neh; 685 struct ext4_extent_idx *fidx; 686 struct ext4_extent *ex; 687 int i = at, k, m, a; 688 ext4_fsblk_t newblock, oldblock; 689 __le32 border; 690 ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */ 691 int err = 0; 692 693 /* make decision: where to split? */ 694 /* FIXME: now decision is simplest: at current extent */ 695 696 /* if current leaf will be split, then we should use 697 * border from split point */ 698 BUG_ON(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr)); 699 if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) { 700 border = path[depth].p_ext[1].ee_block; 701 ext_debug("leaf will be split." 702 " next leaf starts at %d\n", 703 le32_to_cpu(border)); 704 } else { 705 border = newext->ee_block; 706 ext_debug("leaf will be added." 707 " next leaf starts at %d\n", 708 le32_to_cpu(border)); 709 } 710 711 /* 712 * If error occurs, then we break processing 713 * and mark filesystem read-only. index won't 714 * be inserted and tree will be in consistent 715 * state. Next mount will repair buffers too. 716 */ 717 718 /* 719 * Get array to track all allocated blocks. 720 * We need this to handle errors and free blocks 721 * upon them. 722 */ 723 ablocks = kzalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS); 724 if (!ablocks) 725 return -ENOMEM; 726 727 /* allocate all needed blocks */ 728 ext_debug("allocate %d blocks for indexes/leaf\n", depth - at); 729 for (a = 0; a < depth - at; a++) { 730 newblock = ext4_ext_new_meta_block(handle, inode, path, 731 newext, &err); 732 if (newblock == 0) 733 goto cleanup; 734 ablocks[a] = newblock; 735 } 736 737 /* initialize new leaf */ 738 newblock = ablocks[--a]; 739 BUG_ON(newblock == 0); 740 bh = sb_getblk(inode->i_sb, newblock); 741 if (!bh) { 742 err = -EIO; 743 goto cleanup; 744 } 745 lock_buffer(bh); 746 747 err = ext4_journal_get_create_access(handle, bh); 748 if (err) 749 goto cleanup; 750 751 neh = ext_block_hdr(bh); 752 neh->eh_entries = 0; 753 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode)); 754 neh->eh_magic = EXT4_EXT_MAGIC; 755 neh->eh_depth = 0; 756 ex = EXT_FIRST_EXTENT(neh); 757 758 /* move remainder of path[depth] to the new leaf */ 759 BUG_ON(path[depth].p_hdr->eh_entries != path[depth].p_hdr->eh_max); 760 /* start copy from next extent */ 761 /* TODO: we could do it by single memmove */ 762 m = 0; 763 path[depth].p_ext++; 764 while (path[depth].p_ext <= 765 EXT_MAX_EXTENT(path[depth].p_hdr)) { 766 ext_debug("move %d:%llu:%d in new leaf %llu\n", 767 le32_to_cpu(path[depth].p_ext->ee_block), 768 ext_pblock(path[depth].p_ext), 769 ext4_ext_get_actual_len(path[depth].p_ext), 770 newblock); 771 /*memmove(ex++, path[depth].p_ext++, 772 sizeof(struct ext4_extent)); 773 neh->eh_entries++;*/ 774 path[depth].p_ext++; 775 m++; 776 } 777 if (m) { 778 memmove(ex, path[depth].p_ext-m, sizeof(struct ext4_extent)*m); 779 le16_add_cpu(&neh->eh_entries, m); 780 } 781 782 set_buffer_uptodate(bh); 783 unlock_buffer(bh); 784 785 err = ext4_handle_dirty_metadata(handle, inode, bh); 786 if (err) 787 goto cleanup; 788 brelse(bh); 789 bh = NULL; 790 791 /* correct old leaf */ 792 if (m) { 793 err = ext4_ext_get_access(handle, inode, path + depth); 794 if (err) 795 goto cleanup; 796 le16_add_cpu(&path[depth].p_hdr->eh_entries, -m); 797 err = ext4_ext_dirty(handle, inode, path + depth); 798 if (err) 799 goto cleanup; 800 801 } 802 803 /* create intermediate indexes */ 804 k = depth - at - 1; 805 BUG_ON(k < 0); 806 if (k) 807 ext_debug("create %d intermediate indices\n", k); 808 /* insert new index into current index block */ 809 /* current depth stored in i var */ 810 i = depth - 1; 811 while (k--) { 812 oldblock = newblock; 813 newblock = ablocks[--a]; 814 bh = sb_getblk(inode->i_sb, newblock); 815 if (!bh) { 816 err = -EIO; 817 goto cleanup; 818 } 819 lock_buffer(bh); 820 821 err = ext4_journal_get_create_access(handle, bh); 822 if (err) 823 goto cleanup; 824 825 neh = ext_block_hdr(bh); 826 neh->eh_entries = cpu_to_le16(1); 827 neh->eh_magic = EXT4_EXT_MAGIC; 828 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode)); 829 neh->eh_depth = cpu_to_le16(depth - i); 830 fidx = EXT_FIRST_INDEX(neh); 831 fidx->ei_block = border; 832 ext4_idx_store_pblock(fidx, oldblock); 833 834 ext_debug("int.index at %d (block %llu): %u -> %llu\n", 835 i, newblock, le32_to_cpu(border), oldblock); 836 /* copy indexes */ 837 m = 0; 838 path[i].p_idx++; 839 840 ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx, 841 EXT_MAX_INDEX(path[i].p_hdr)); 842 BUG_ON(EXT_MAX_INDEX(path[i].p_hdr) != 843 EXT_LAST_INDEX(path[i].p_hdr)); 844 while (path[i].p_idx <= EXT_MAX_INDEX(path[i].p_hdr)) { 845 ext_debug("%d: move %d:%llu in new index %llu\n", i, 846 le32_to_cpu(path[i].p_idx->ei_block), 847 idx_pblock(path[i].p_idx), 848 newblock); 849 /*memmove(++fidx, path[i].p_idx++, 850 sizeof(struct ext4_extent_idx)); 851 neh->eh_entries++; 852 BUG_ON(neh->eh_entries > neh->eh_max);*/ 853 path[i].p_idx++; 854 m++; 855 } 856 if (m) { 857 memmove(++fidx, path[i].p_idx - m, 858 sizeof(struct ext4_extent_idx) * m); 859 le16_add_cpu(&neh->eh_entries, m); 860 } 861 set_buffer_uptodate(bh); 862 unlock_buffer(bh); 863 864 err = ext4_handle_dirty_metadata(handle, inode, bh); 865 if (err) 866 goto cleanup; 867 brelse(bh); 868 bh = NULL; 869 870 /* correct old index */ 871 if (m) { 872 err = ext4_ext_get_access(handle, inode, path + i); 873 if (err) 874 goto cleanup; 875 le16_add_cpu(&path[i].p_hdr->eh_entries, -m); 876 err = ext4_ext_dirty(handle, inode, path + i); 877 if (err) 878 goto cleanup; 879 } 880 881 i--; 882 } 883 884 /* insert new index */ 885 err = ext4_ext_insert_index(handle, inode, path + at, 886 le32_to_cpu(border), newblock); 887 888cleanup: 889 if (bh) { 890 if (buffer_locked(bh)) 891 unlock_buffer(bh); 892 brelse(bh); 893 } 894 895 if (err) { 896 /* free all allocated blocks in error case */ 897 for (i = 0; i < depth; i++) { 898 if (!ablocks[i]) 899 continue; 900 ext4_free_blocks(handle, inode, ablocks[i], 1, 1); 901 } 902 } 903 kfree(ablocks); 904 905 return err; 906} 907 908/* 909 * ext4_ext_grow_indepth: 910 * implements tree growing procedure: 911 * - allocates new block 912 * - moves top-level data (index block or leaf) into the new block 913 * - initializes new top-level, creating index that points to the 914 * just created block 915 */ 916static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode, 917 struct ext4_ext_path *path, 918 struct ext4_extent *newext) 919{ 920 struct ext4_ext_path *curp = path; 921 struct ext4_extent_header *neh; 922 struct ext4_extent_idx *fidx; 923 struct buffer_head *bh; 924 ext4_fsblk_t newblock; 925 int err = 0; 926 927 newblock = ext4_ext_new_meta_block(handle, inode, path, newext, &err); 928 if (newblock == 0) 929 return err; 930 931 bh = sb_getblk(inode->i_sb, newblock); 932 if (!bh) { 933 err = -EIO; 934 ext4_std_error(inode->i_sb, err); 935 return err; 936 } 937 lock_buffer(bh); 938 939 err = ext4_journal_get_create_access(handle, bh); 940 if (err) { 941 unlock_buffer(bh); 942 goto out; 943 } 944 945 /* move top-level index/leaf into new block */ 946 memmove(bh->b_data, curp->p_hdr, sizeof(EXT4_I(inode)->i_data)); 947 948 /* set size of new block */ 949 neh = ext_block_hdr(bh); 950 /* old root could have indexes or leaves 951 * so calculate e_max right way */ 952 if (ext_depth(inode)) 953 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode)); 954 else 955 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode)); 956 neh->eh_magic = EXT4_EXT_MAGIC; 957 set_buffer_uptodate(bh); 958 unlock_buffer(bh); 959 960 err = ext4_handle_dirty_metadata(handle, inode, bh); 961 if (err) 962 goto out; 963 964 /* create index in new top-level index: num,max,pointer */ 965 err = ext4_ext_get_access(handle, inode, curp); 966 if (err) 967 goto out; 968 969 curp->p_hdr->eh_magic = EXT4_EXT_MAGIC; 970 curp->p_hdr->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode)); 971 curp->p_hdr->eh_entries = cpu_to_le16(1); 972 curp->p_idx = EXT_FIRST_INDEX(curp->p_hdr); 973 974 if (path[0].p_hdr->eh_depth) 975 curp->p_idx->ei_block = 976 EXT_FIRST_INDEX(path[0].p_hdr)->ei_block; 977 else 978 curp->p_idx->ei_block = 979 EXT_FIRST_EXTENT(path[0].p_hdr)->ee_block; 980 ext4_idx_store_pblock(curp->p_idx, newblock); 981 982 neh = ext_inode_hdr(inode); 983 fidx = EXT_FIRST_INDEX(neh); 984 ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n", 985 le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max), 986 le32_to_cpu(fidx->ei_block), idx_pblock(fidx)); 987 988 neh->eh_depth = cpu_to_le16(path->p_depth + 1); 989 err = ext4_ext_dirty(handle, inode, curp); 990out: 991 brelse(bh); 992 993 return err; 994} 995 996/* 997 * ext4_ext_create_new_leaf: 998 * finds empty index and adds new leaf. 999 * if no free index is found, then it requests in-depth growing. 1000 */ 1001static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode, 1002 struct ext4_ext_path *path, 1003 struct ext4_extent *newext) 1004{ 1005 struct ext4_ext_path *curp; 1006 int depth, i, err = 0; 1007 1008repeat: 1009 i = depth = ext_depth(inode); 1010 1011 /* walk up to the tree and look for free index entry */ 1012 curp = path + depth; 1013 while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) { 1014 i--; 1015 curp--; 1016 } 1017 1018 /* we use already allocated block for index block, 1019 * so subsequent data blocks should be contiguous */ 1020 if (EXT_HAS_FREE_INDEX(curp)) { 1021 /* if we found index with free entry, then use that 1022 * entry: create all needed subtree and add new leaf */ 1023 err = ext4_ext_split(handle, inode, path, newext, i); 1024 if (err) 1025 goto out; 1026 1027 /* refill path */ 1028 ext4_ext_drop_refs(path); 1029 path = ext4_ext_find_extent(inode, 1030 (ext4_lblk_t)le32_to_cpu(newext->ee_block), 1031 path); 1032 if (IS_ERR(path)) 1033 err = PTR_ERR(path); 1034 } else { 1035 /* tree is full, time to grow in depth */ 1036 err = ext4_ext_grow_indepth(handle, inode, path, newext); 1037 if (err) 1038 goto out; 1039 1040 /* refill path */ 1041 ext4_ext_drop_refs(path); 1042 path = ext4_ext_find_extent(inode, 1043 (ext4_lblk_t)le32_to_cpu(newext->ee_block), 1044 path); 1045 if (IS_ERR(path)) { 1046 err = PTR_ERR(path); 1047 goto out; 1048 } 1049 1050 /* 1051 * only first (depth 0 -> 1) produces free space; 1052 * in all other cases we have to split the grown tree 1053 */ 1054 depth = ext_depth(inode); 1055 if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) { 1056 /* now we need to split */ 1057 goto repeat; 1058 } 1059 } 1060 1061out: 1062 return err; 1063} 1064 1065/* 1066 * search the closest allocated block to the left for *logical 1067 * and returns it at @logical + it's physical address at @phys 1068 * if *logical is the smallest allocated block, the function 1069 * returns 0 at @phys 1070 * return value contains 0 (success) or error code 1071 */ 1072int 1073ext4_ext_search_left(struct inode *inode, struct ext4_ext_path *path, 1074 ext4_lblk_t *logical, ext4_fsblk_t *phys) 1075{ 1076 struct ext4_extent_idx *ix; 1077 struct ext4_extent *ex; 1078 int depth, ee_len; 1079 1080 BUG_ON(path == NULL); 1081 depth = path->p_depth; 1082 *phys = 0; 1083 1084 if (depth == 0 && path->p_ext == NULL) 1085 return 0; 1086 1087 /* usually extent in the path covers blocks smaller 1088 * then *logical, but it can be that extent is the 1089 * first one in the file */ 1090 1091 ex = path[depth].p_ext; 1092 ee_len = ext4_ext_get_actual_len(ex); 1093 if (*logical < le32_to_cpu(ex->ee_block)) { 1094 BUG_ON(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex); 1095 while (--depth >= 0) { 1096 ix = path[depth].p_idx; 1097 BUG_ON(ix != EXT_FIRST_INDEX(path[depth].p_hdr)); 1098 } 1099 return 0; 1100 } 1101 1102 BUG_ON(*logical < (le32_to_cpu(ex->ee_block) + ee_len)); 1103 1104 *logical = le32_to_cpu(ex->ee_block) + ee_len - 1; 1105 *phys = ext_pblock(ex) + ee_len - 1; 1106 return 0; 1107} 1108 1109/* 1110 * search the closest allocated block to the right for *logical 1111 * and returns it at @logical + it's physical address at @phys 1112 * if *logical is the smallest allocated block, the function 1113 * returns 0 at @phys 1114 * return value contains 0 (success) or error code 1115 */ 1116int 1117ext4_ext_search_right(struct inode *inode, struct ext4_ext_path *path, 1118 ext4_lblk_t *logical, ext4_fsblk_t *phys) 1119{ 1120 struct buffer_head *bh = NULL; 1121 struct ext4_extent_header *eh; 1122 struct ext4_extent_idx *ix; 1123 struct ext4_extent *ex; 1124 ext4_fsblk_t block; 1125 int depth, ee_len; 1126 1127 BUG_ON(path == NULL); 1128 depth = path->p_depth; 1129 *phys = 0; 1130 1131 if (depth == 0 && path->p_ext == NULL) 1132 return 0; 1133 1134 /* usually extent in the path covers blocks smaller 1135 * then *logical, but it can be that extent is the 1136 * first one in the file */ 1137 1138 ex = path[depth].p_ext; 1139 ee_len = ext4_ext_get_actual_len(ex); 1140 if (*logical < le32_to_cpu(ex->ee_block)) { 1141 BUG_ON(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex); 1142 while (--depth >= 0) { 1143 ix = path[depth].p_idx; 1144 BUG_ON(ix != EXT_FIRST_INDEX(path[depth].p_hdr)); 1145 } 1146 *logical = le32_to_cpu(ex->ee_block); 1147 *phys = ext_pblock(ex); 1148 return 0; 1149 } 1150 1151 BUG_ON(*logical < (le32_to_cpu(ex->ee_block) + ee_len)); 1152 1153 if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) { 1154 /* next allocated block in this leaf */ 1155 ex++; 1156 *logical = le32_to_cpu(ex->ee_block); 1157 *phys = ext_pblock(ex); 1158 return 0; 1159 } 1160 1161 /* go up and search for index to the right */ 1162 while (--depth >= 0) { 1163 ix = path[depth].p_idx; 1164 if (ix != EXT_LAST_INDEX(path[depth].p_hdr)) 1165 goto got_index; 1166 } 1167 1168 /* we've gone up to the root and found no index to the right */ 1169 return 0; 1170 1171got_index: 1172 /* we've found index to the right, let's 1173 * follow it and find the closest allocated 1174 * block to the right */ 1175 ix++; 1176 block = idx_pblock(ix); 1177 while (++depth < path->p_depth) { 1178 bh = sb_bread(inode->i_sb, block); 1179 if (bh == NULL) 1180 return -EIO; 1181 eh = ext_block_hdr(bh); 1182 if (ext4_ext_check_header(inode, eh, depth)) { 1183 put_bh(bh); 1184 return -EIO; 1185 } 1186 ix = EXT_FIRST_INDEX(eh); 1187 block = idx_pblock(ix); 1188 put_bh(bh); 1189 } 1190 1191 bh = sb_bread(inode->i_sb, block); 1192 if (bh == NULL) 1193 return -EIO; 1194 eh = ext_block_hdr(bh); 1195 if (ext4_ext_check_header(inode, eh, path->p_depth - depth)) { 1196 put_bh(bh); 1197 return -EIO; 1198 } 1199 ex = EXT_FIRST_EXTENT(eh); 1200 *logical = le32_to_cpu(ex->ee_block); 1201 *phys = ext_pblock(ex); 1202 put_bh(bh); 1203 return 0; 1204} 1205 1206/* 1207 * ext4_ext_next_allocated_block: 1208 * returns allocated block in subsequent extent or EXT_MAX_BLOCK. 1209 * NOTE: it considers block number from index entry as 1210 * allocated block. Thus, index entries have to be consistent 1211 * with leaves. 1212 */ 1213static ext4_lblk_t 1214ext4_ext_next_allocated_block(struct ext4_ext_path *path) 1215{ 1216 int depth; 1217 1218 BUG_ON(path == NULL); 1219 depth = path->p_depth; 1220 1221 if (depth == 0 && path->p_ext == NULL) 1222 return EXT_MAX_BLOCK; 1223 1224 while (depth >= 0) { 1225 if (depth == path->p_depth) { 1226 /* leaf */ 1227 if (path[depth].p_ext != 1228 EXT_LAST_EXTENT(path[depth].p_hdr)) 1229 return le32_to_cpu(path[depth].p_ext[1].ee_block); 1230 } else { 1231 /* index */ 1232 if (path[depth].p_idx != 1233 EXT_LAST_INDEX(path[depth].p_hdr)) 1234 return le32_to_cpu(path[depth].p_idx[1].ei_block); 1235 } 1236 depth--; 1237 } 1238 1239 return EXT_MAX_BLOCK; 1240} 1241 1242/* 1243 * ext4_ext_next_leaf_block: 1244 * returns first allocated block from next leaf or EXT_MAX_BLOCK 1245 */ 1246static ext4_lblk_t ext4_ext_next_leaf_block(struct inode *inode, 1247 struct ext4_ext_path *path) 1248{ 1249 int depth; 1250 1251 BUG_ON(path == NULL); 1252 depth = path->p_depth; 1253 1254 /* zero-tree has no leaf blocks at all */ 1255 if (depth == 0) 1256 return EXT_MAX_BLOCK; 1257 1258 /* go to index block */ 1259 depth--; 1260 1261 while (depth >= 0) { 1262 if (path[depth].p_idx != 1263 EXT_LAST_INDEX(path[depth].p_hdr)) 1264 return (ext4_lblk_t) 1265 le32_to_cpu(path[depth].p_idx[1].ei_block); 1266 depth--; 1267 } 1268 1269 return EXT_MAX_BLOCK; 1270} 1271 1272/* 1273 * ext4_ext_correct_indexes: 1274 * if leaf gets modified and modified extent is first in the leaf, 1275 * then we have to correct all indexes above. 1276 * TODO: do we need to correct tree in all cases? 1277 */ 1278static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode, 1279 struct ext4_ext_path *path) 1280{ 1281 struct ext4_extent_header *eh; 1282 int depth = ext_depth(inode); 1283 struct ext4_extent *ex; 1284 __le32 border; 1285 int k, err = 0; 1286 1287 eh = path[depth].p_hdr; 1288 ex = path[depth].p_ext; 1289 BUG_ON(ex == NULL); 1290 BUG_ON(eh == NULL); 1291 1292 if (depth == 0) { 1293 /* there is no tree at all */ 1294 return 0; 1295 } 1296 1297 if (ex != EXT_FIRST_EXTENT(eh)) { 1298 /* we correct tree if first leaf got modified only */ 1299 return 0; 1300 } 1301 1302 /* 1303 * TODO: we need correction if border is smaller than current one 1304 */ 1305 k = depth - 1; 1306 border = path[depth].p_ext->ee_block; 1307 err = ext4_ext_get_access(handle, inode, path + k); 1308 if (err) 1309 return err; 1310 path[k].p_idx->ei_block = border; 1311 err = ext4_ext_dirty(handle, inode, path + k); 1312 if (err) 1313 return err; 1314 1315 while (k--) { 1316 /* change all left-side indexes */ 1317 if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr)) 1318 break; 1319 err = ext4_ext_get_access(handle, inode, path + k); 1320 if (err) 1321 break; 1322 path[k].p_idx->ei_block = border; 1323 err = ext4_ext_dirty(handle, inode, path + k); 1324 if (err) 1325 break; 1326 } 1327 1328 return err; 1329} 1330 1331static int 1332ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1, 1333 struct ext4_extent *ex2) 1334{ 1335 unsigned short ext1_ee_len, ext2_ee_len, max_len; 1336 1337 /* 1338 * Make sure that either both extents are uninitialized, or 1339 * both are _not_. 1340 */ 1341 if (ext4_ext_is_uninitialized(ex1) ^ ext4_ext_is_uninitialized(ex2)) 1342 return 0; 1343 1344 if (ext4_ext_is_uninitialized(ex1)) 1345 max_len = EXT_UNINIT_MAX_LEN; 1346 else 1347 max_len = EXT_INIT_MAX_LEN; 1348 1349 ext1_ee_len = ext4_ext_get_actual_len(ex1); 1350 ext2_ee_len = ext4_ext_get_actual_len(ex2); 1351 1352 if (le32_to_cpu(ex1->ee_block) + ext1_ee_len != 1353 le32_to_cpu(ex2->ee_block)) 1354 return 0; 1355 1356 /* 1357 * To allow future support for preallocated extents to be added 1358 * as an RO_COMPAT feature, refuse to merge to extents if 1359 * this can result in the top bit of ee_len being set. 1360 */ 1361 if (ext1_ee_len + ext2_ee_len > max_len) 1362 return 0; 1363#ifdef AGGRESSIVE_TEST 1364 if (ext1_ee_len >= 4) 1365 return 0; 1366#endif 1367 1368 if (ext_pblock(ex1) + ext1_ee_len == ext_pblock(ex2)) 1369 return 1; 1370 return 0; 1371} 1372 1373/* 1374 * This function tries to merge the "ex" extent to the next extent in the tree. 1375 * It always tries to merge towards right. If you want to merge towards 1376 * left, pass "ex - 1" as argument instead of "ex". 1377 * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns 1378 * 1 if they got merged. 1379 */ 1380int ext4_ext_try_to_merge(struct inode *inode, 1381 struct ext4_ext_path *path, 1382 struct ext4_extent *ex) 1383{ 1384 struct ext4_extent_header *eh; 1385 unsigned int depth, len; 1386 int merge_done = 0; 1387 int uninitialized = 0; 1388 1389 depth = ext_depth(inode); 1390 BUG_ON(path[depth].p_hdr == NULL); 1391 eh = path[depth].p_hdr; 1392 1393 while (ex < EXT_LAST_EXTENT(eh)) { 1394 if (!ext4_can_extents_be_merged(inode, ex, ex + 1)) 1395 break; 1396 /* merge with next extent! */ 1397 if (ext4_ext_is_uninitialized(ex)) 1398 uninitialized = 1; 1399 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex) 1400 + ext4_ext_get_actual_len(ex + 1)); 1401 if (uninitialized) 1402 ext4_ext_mark_uninitialized(ex); 1403 1404 if (ex + 1 < EXT_LAST_EXTENT(eh)) { 1405 len = (EXT_LAST_EXTENT(eh) - ex - 1) 1406 * sizeof(struct ext4_extent); 1407 memmove(ex + 1, ex + 2, len); 1408 } 1409 le16_add_cpu(&eh->eh_entries, -1); 1410 merge_done = 1; 1411 WARN_ON(eh->eh_entries == 0); 1412 if (!eh->eh_entries) 1413 ext4_error(inode->i_sb, "ext4_ext_try_to_merge", 1414 "inode#%lu, eh->eh_entries = 0!", inode->i_ino); 1415 } 1416 1417 return merge_done; 1418} 1419 1420/* 1421 * check if a portion of the "newext" extent overlaps with an 1422 * existing extent. 1423 * 1424 * If there is an overlap discovered, it updates the length of the newext 1425 * such that there will be no overlap, and then returns 1. 1426 * If there is no overlap found, it returns 0. 1427 */ 1428unsigned int ext4_ext_check_overlap(struct inode *inode, 1429 struct ext4_extent *newext, 1430 struct ext4_ext_path *path) 1431{ 1432 ext4_lblk_t b1, b2; 1433 unsigned int depth, len1; 1434 unsigned int ret = 0; 1435 1436 b1 = le32_to_cpu(newext->ee_block); 1437 len1 = ext4_ext_get_actual_len(newext); 1438 depth = ext_depth(inode); 1439 if (!path[depth].p_ext) 1440 goto out; 1441 b2 = le32_to_cpu(path[depth].p_ext->ee_block); 1442 1443 /* 1444 * get the next allocated block if the extent in the path 1445 * is before the requested block(s) 1446 */ 1447 if (b2 < b1) { 1448 b2 = ext4_ext_next_allocated_block(path); 1449 if (b2 == EXT_MAX_BLOCK) 1450 goto out; 1451 } 1452 1453 /* check for wrap through zero on extent logical start block*/ 1454 if (b1 + len1 < b1) { 1455 len1 = EXT_MAX_BLOCK - b1; 1456 newext->ee_len = cpu_to_le16(len1); 1457 ret = 1; 1458 } 1459 1460 /* check for overlap */ 1461 if (b1 + len1 > b2) { 1462 newext->ee_len = cpu_to_le16(b2 - b1); 1463 ret = 1; 1464 } 1465out: 1466 return ret; 1467} 1468 1469/* 1470 * ext4_ext_insert_extent: 1471 * tries to merge requsted extent into the existing extent or 1472 * inserts requested extent as new one into the tree, 1473 * creating new leaf in the no-space case. 1474 */ 1475int ext4_ext_insert_extent(handle_t *handle, struct inode *inode, 1476 struct ext4_ext_path *path, 1477 struct ext4_extent *newext) 1478{ 1479 struct ext4_extent_header *eh; 1480 struct ext4_extent *ex, *fex; 1481 struct ext4_extent *nearex; /* nearest extent */ 1482 struct ext4_ext_path *npath = NULL; 1483 int depth, len, err; 1484 ext4_lblk_t next; 1485 unsigned uninitialized = 0; 1486 1487 BUG_ON(ext4_ext_get_actual_len(newext) == 0); 1488 depth = ext_depth(inode); 1489 ex = path[depth].p_ext; 1490 BUG_ON(path[depth].p_hdr == NULL); 1491 1492 /* try to insert block into found extent and return */ 1493 if (ex && ext4_can_extents_be_merged(inode, ex, newext)) { 1494 ext_debug("append %d block to %d:%d (from %llu)\n", 1495 ext4_ext_get_actual_len(newext), 1496 le32_to_cpu(ex->ee_block), 1497 ext4_ext_get_actual_len(ex), ext_pblock(ex)); 1498 err = ext4_ext_get_access(handle, inode, path + depth); 1499 if (err) 1500 return err; 1501 1502 /* 1503 * ext4_can_extents_be_merged should have checked that either 1504 * both extents are uninitialized, or both aren't. Thus we 1505 * need to check only one of them here. 1506 */ 1507 if (ext4_ext_is_uninitialized(ex)) 1508 uninitialized = 1; 1509 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex) 1510 + ext4_ext_get_actual_len(newext)); 1511 if (uninitialized) 1512 ext4_ext_mark_uninitialized(ex); 1513 eh = path[depth].p_hdr; 1514 nearex = ex; 1515 goto merge; 1516 } 1517 1518repeat: 1519 depth = ext_depth(inode); 1520 eh = path[depth].p_hdr; 1521 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) 1522 goto has_space; 1523 1524 /* probably next leaf has space for us? */ 1525 fex = EXT_LAST_EXTENT(eh); 1526 next = ext4_ext_next_leaf_block(inode, path); 1527 if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block) 1528 && next != EXT_MAX_BLOCK) { 1529 ext_debug("next leaf block - %d\n", next); 1530 BUG_ON(npath != NULL); 1531 npath = ext4_ext_find_extent(inode, next, NULL); 1532 if (IS_ERR(npath)) 1533 return PTR_ERR(npath); 1534 BUG_ON(npath->p_depth != path->p_depth); 1535 eh = npath[depth].p_hdr; 1536 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) { 1537 ext_debug("next leaf isnt full(%d)\n", 1538 le16_to_cpu(eh->eh_entries)); 1539 path = npath; 1540 goto repeat; 1541 } 1542 ext_debug("next leaf has no free space(%d,%d)\n", 1543 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max)); 1544 } 1545 1546 /* 1547 * There is no free space in the found leaf. 1548 * We're gonna add a new leaf in the tree. 1549 */ 1550 err = ext4_ext_create_new_leaf(handle, inode, path, newext); 1551 if (err) 1552 goto cleanup; 1553 depth = ext_depth(inode); 1554 eh = path[depth].p_hdr; 1555 1556has_space: 1557 nearex = path[depth].p_ext; 1558 1559 err = ext4_ext_get_access(handle, inode, path + depth); 1560 if (err) 1561 goto cleanup; 1562 1563 if (!nearex) { 1564 /* there is no extent in this leaf, create first one */ 1565 ext_debug("first extent in the leaf: %d:%llu:%d\n", 1566 le32_to_cpu(newext->ee_block), 1567 ext_pblock(newext), 1568 ext4_ext_get_actual_len(newext)); 1569 path[depth].p_ext = EXT_FIRST_EXTENT(eh); 1570 } else if (le32_to_cpu(newext->ee_block) 1571 > le32_to_cpu(nearex->ee_block)) { 1572/* BUG_ON(newext->ee_block == nearex->ee_block); */ 1573 if (nearex != EXT_LAST_EXTENT(eh)) { 1574 len = EXT_MAX_EXTENT(eh) - nearex; 1575 len = (len - 1) * sizeof(struct ext4_extent); 1576 len = len < 0 ? 0 : len; 1577 ext_debug("insert %d:%llu:%d after: nearest 0x%p, " 1578 "move %d from 0x%p to 0x%p\n", 1579 le32_to_cpu(newext->ee_block), 1580 ext_pblock(newext), 1581 ext4_ext_get_actual_len(newext), 1582 nearex, len, nearex + 1, nearex + 2); 1583 memmove(nearex + 2, nearex + 1, len); 1584 } 1585 path[depth].p_ext = nearex + 1; 1586 } else { 1587 BUG_ON(newext->ee_block == nearex->ee_block); 1588 len = (EXT_MAX_EXTENT(eh) - nearex) * sizeof(struct ext4_extent); 1589 len = len < 0 ? 0 : len; 1590 ext_debug("insert %d:%llu:%d before: nearest 0x%p, " 1591 "move %d from 0x%p to 0x%p\n", 1592 le32_to_cpu(newext->ee_block), 1593 ext_pblock(newext), 1594 ext4_ext_get_actual_len(newext), 1595 nearex, len, nearex + 1, nearex + 2); 1596 memmove(nearex + 1, nearex, len); 1597 path[depth].p_ext = nearex; 1598 } 1599 1600 le16_add_cpu(&eh->eh_entries, 1); 1601 nearex = path[depth].p_ext; 1602 nearex->ee_block = newext->ee_block; 1603 ext4_ext_store_pblock(nearex, ext_pblock(newext)); 1604 nearex->ee_len = newext->ee_len; 1605 1606merge: 1607 /* try to merge extents to the right */ 1608 ext4_ext_try_to_merge(inode, path, nearex); 1609 1610 /* try to merge extents to the left */ 1611 1612 /* time to correct all indexes above */ 1613 err = ext4_ext_correct_indexes(handle, inode, path); 1614 if (err) 1615 goto cleanup; 1616 1617 err = ext4_ext_dirty(handle, inode, path + depth); 1618 1619cleanup: 1620 if (npath) { 1621 ext4_ext_drop_refs(npath); 1622 kfree(npath); 1623 } 1624 ext4_ext_invalidate_cache(inode); 1625 return err; 1626} 1627 1628int ext4_ext_walk_space(struct inode *inode, ext4_lblk_t block, 1629 ext4_lblk_t num, ext_prepare_callback func, 1630 void *cbdata) 1631{ 1632 struct ext4_ext_path *path = NULL; 1633 struct ext4_ext_cache cbex; 1634 struct ext4_extent *ex; 1635 ext4_lblk_t next, start = 0, end = 0; 1636 ext4_lblk_t last = block + num; 1637 int depth, exists, err = 0; 1638 1639 BUG_ON(func == NULL); 1640 BUG_ON(inode == NULL); 1641 1642 while (block < last && block != EXT_MAX_BLOCK) { 1643 num = last - block; 1644 /* find extent for this block */ 1645 path = ext4_ext_find_extent(inode, block, path); 1646 if (IS_ERR(path)) { 1647 err = PTR_ERR(path); 1648 path = NULL; 1649 break; 1650 } 1651 1652 depth = ext_depth(inode); 1653 BUG_ON(path[depth].p_hdr == NULL); 1654 ex = path[depth].p_ext; 1655 next = ext4_ext_next_allocated_block(path); 1656 1657 exists = 0; 1658 if (!ex) { 1659 /* there is no extent yet, so try to allocate 1660 * all requested space */ 1661 start = block; 1662 end = block + num; 1663 } else if (le32_to_cpu(ex->ee_block) > block) { 1664 /* need to allocate space before found extent */ 1665 start = block; 1666 end = le32_to_cpu(ex->ee_block); 1667 if (block + num < end) 1668 end = block + num; 1669 } else if (block >= le32_to_cpu(ex->ee_block) 1670 + ext4_ext_get_actual_len(ex)) { 1671 /* need to allocate space after found extent */ 1672 start = block; 1673 end = block + num; 1674 if (end >= next) 1675 end = next; 1676 } else if (block >= le32_to_cpu(ex->ee_block)) { 1677 /* 1678 * some part of requested space is covered 1679 * by found extent 1680 */ 1681 start = block; 1682 end = le32_to_cpu(ex->ee_block) 1683 + ext4_ext_get_actual_len(ex); 1684 if (block + num < end) 1685 end = block + num; 1686 exists = 1; 1687 } else { 1688 BUG(); 1689 } 1690 BUG_ON(end <= start); 1691 1692 if (!exists) { 1693 cbex.ec_block = start; 1694 cbex.ec_len = end - start; 1695 cbex.ec_start = 0; 1696 cbex.ec_type = EXT4_EXT_CACHE_GAP; 1697 } else { 1698 cbex.ec_block = le32_to_cpu(ex->ee_block); 1699 cbex.ec_len = ext4_ext_get_actual_len(ex); 1700 cbex.ec_start = ext_pblock(ex); 1701 cbex.ec_type = EXT4_EXT_CACHE_EXTENT; 1702 } 1703 1704 BUG_ON(cbex.ec_len == 0); 1705 err = func(inode, path, &cbex, ex, cbdata); 1706 ext4_ext_drop_refs(path); 1707 1708 if (err < 0) 1709 break; 1710 1711 if (err == EXT_REPEAT) 1712 continue; 1713 else if (err == EXT_BREAK) { 1714 err = 0; 1715 break; 1716 } 1717 1718 if (ext_depth(inode) != depth) { 1719 /* depth was changed. we have to realloc path */ 1720 kfree(path); 1721 path = NULL; 1722 } 1723 1724 block = cbex.ec_block + cbex.ec_len; 1725 } 1726 1727 if (path) { 1728 ext4_ext_drop_refs(path); 1729 kfree(path); 1730 } 1731 1732 return err; 1733} 1734 1735static void 1736ext4_ext_put_in_cache(struct inode *inode, ext4_lblk_t block, 1737 __u32 len, ext4_fsblk_t start, int type) 1738{ 1739 struct ext4_ext_cache *cex; 1740 BUG_ON(len == 0); 1741 cex = &EXT4_I(inode)->i_cached_extent; 1742 cex->ec_type = type; 1743 cex->ec_block = block; 1744 cex->ec_len = len; 1745 cex->ec_start = start; 1746} 1747 1748/* 1749 * ext4_ext_put_gap_in_cache: 1750 * calculate boundaries of the gap that the requested block fits into 1751 * and cache this gap 1752 */ 1753static void 1754ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path, 1755 ext4_lblk_t block) 1756{ 1757 int depth = ext_depth(inode); 1758 unsigned long len; 1759 ext4_lblk_t lblock; 1760 struct ext4_extent *ex; 1761 1762 ex = path[depth].p_ext; 1763 if (ex == NULL) { 1764 /* there is no extent yet, so gap is [0;-] */ 1765 lblock = 0; 1766 len = EXT_MAX_BLOCK; 1767 ext_debug("cache gap(whole file):"); 1768 } else if (block < le32_to_cpu(ex->ee_block)) { 1769 lblock = block; 1770 len = le32_to_cpu(ex->ee_block) - block; 1771 ext_debug("cache gap(before): %u [%u:%u]", 1772 block, 1773 le32_to_cpu(ex->ee_block), 1774 ext4_ext_get_actual_len(ex)); 1775 } else if (block >= le32_to_cpu(ex->ee_block) 1776 + ext4_ext_get_actual_len(ex)) { 1777 ext4_lblk_t next; 1778 lblock = le32_to_cpu(ex->ee_block) 1779 + ext4_ext_get_actual_len(ex); 1780 1781 next = ext4_ext_next_allocated_block(path); 1782 ext_debug("cache gap(after): [%u:%u] %u", 1783 le32_to_cpu(ex->ee_block), 1784 ext4_ext_get_actual_len(ex), 1785 block); 1786 BUG_ON(next == lblock); 1787 len = next - lblock; 1788 } else { 1789 lblock = len = 0; 1790 BUG(); 1791 } 1792 1793 ext_debug(" -> %u:%lu\n", lblock, len); 1794 ext4_ext_put_in_cache(inode, lblock, len, 0, EXT4_EXT_CACHE_GAP); 1795} 1796 1797static int 1798ext4_ext_in_cache(struct inode *inode, ext4_lblk_t block, 1799 struct ext4_extent *ex) 1800{ 1801 struct ext4_ext_cache *cex; 1802 1803 cex = &EXT4_I(inode)->i_cached_extent; 1804 1805 /* has cache valid data? */ 1806 if (cex->ec_type == EXT4_EXT_CACHE_NO) 1807 return EXT4_EXT_CACHE_NO; 1808 1809 BUG_ON(cex->ec_type != EXT4_EXT_CACHE_GAP && 1810 cex->ec_type != EXT4_EXT_CACHE_EXTENT); 1811 if (block >= cex->ec_block && block < cex->ec_block + cex->ec_len) { 1812 ex->ee_block = cpu_to_le32(cex->ec_block); 1813 ext4_ext_store_pblock(ex, cex->ec_start); 1814 ex->ee_len = cpu_to_le16(cex->ec_len); 1815 ext_debug("%u cached by %u:%u:%llu\n", 1816 block, 1817 cex->ec_block, cex->ec_len, cex->ec_start); 1818 return cex->ec_type; 1819 } 1820 1821 /* not in cache */ 1822 return EXT4_EXT_CACHE_NO; 1823} 1824 1825/* 1826 * ext4_ext_rm_idx: 1827 * removes index from the index block. 1828 * It's used in truncate case only, thus all requests are for 1829 * last index in the block only. 1830 */ 1831static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode, 1832 struct ext4_ext_path *path) 1833{ 1834 struct buffer_head *bh; 1835 int err; 1836 ext4_fsblk_t leaf; 1837 1838 /* free index block */ 1839 path--; 1840 leaf = idx_pblock(path->p_idx); 1841 BUG_ON(path->p_hdr->eh_entries == 0); 1842 err = ext4_ext_get_access(handle, inode, path); 1843 if (err) 1844 return err; 1845 le16_add_cpu(&path->p_hdr->eh_entries, -1); 1846 err = ext4_ext_dirty(handle, inode, path); 1847 if (err) 1848 return err; 1849 ext_debug("index is empty, remove it, free block %llu\n", leaf); 1850 bh = sb_find_get_block(inode->i_sb, leaf); 1851 ext4_forget(handle, 1, inode, bh, leaf); 1852 ext4_free_blocks(handle, inode, leaf, 1, 1); 1853 return err; 1854} 1855 1856/* 1857 * ext4_ext_calc_credits_for_single_extent: 1858 * This routine returns max. credits that needed to insert an extent 1859 * to the extent tree. 1860 * When pass the actual path, the caller should calculate credits 1861 * under i_data_sem. 1862 */ 1863int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks, 1864 struct ext4_ext_path *path) 1865{ 1866 if (path) { 1867 int depth = ext_depth(inode); 1868 int ret = 0; 1869 1870 /* probably there is space in leaf? */ 1871 if (le16_to_cpu(path[depth].p_hdr->eh_entries) 1872 < le16_to_cpu(path[depth].p_hdr->eh_max)) { 1873 1874 /* 1875 * There are some space in the leaf tree, no 1876 * need to account for leaf block credit 1877 * 1878 * bitmaps and block group descriptor blocks 1879 * and other metadat blocks still need to be 1880 * accounted. 1881 */ 1882 /* 1 bitmap, 1 block group descriptor */ 1883 ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb); 1884 } 1885 } 1886 1887 return ext4_chunk_trans_blocks(inode, nrblocks); 1888} 1889 1890/* 1891 * How many index/leaf blocks need to change/allocate to modify nrblocks? 1892 * 1893 * if nrblocks are fit in a single extent (chunk flag is 1), then 1894 * in the worse case, each tree level index/leaf need to be changed 1895 * if the tree split due to insert a new extent, then the old tree 1896 * index/leaf need to be updated too 1897 * 1898 * If the nrblocks are discontiguous, they could cause 1899 * the whole tree split more than once, but this is really rare. 1900 */ 1901int ext4_ext_index_trans_blocks(struct inode *inode, int nrblocks, int chunk) 1902{ 1903 int index; 1904 int depth = ext_depth(inode); 1905 1906 if (chunk) 1907 index = depth * 2; 1908 else 1909 index = depth * 3; 1910 1911 return index; 1912} 1913 1914static int ext4_remove_blocks(handle_t *handle, struct inode *inode, 1915 struct ext4_extent *ex, 1916 ext4_lblk_t from, ext4_lblk_t to) 1917{ 1918 struct buffer_head *bh; 1919 unsigned short ee_len = ext4_ext_get_actual_len(ex); 1920 int i, metadata = 0; 1921 1922 if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) 1923 metadata = 1; 1924#ifdef EXTENTS_STATS 1925 { 1926 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 1927 spin_lock(&sbi->s_ext_stats_lock); 1928 sbi->s_ext_blocks += ee_len; 1929 sbi->s_ext_extents++; 1930 if (ee_len < sbi->s_ext_min) 1931 sbi->s_ext_min = ee_len; 1932 if (ee_len > sbi->s_ext_max) 1933 sbi->s_ext_max = ee_len; 1934 if (ext_depth(inode) > sbi->s_depth_max) 1935 sbi->s_depth_max = ext_depth(inode); 1936 spin_unlock(&sbi->s_ext_stats_lock); 1937 } 1938#endif 1939 if (from >= le32_to_cpu(ex->ee_block) 1940 && to == le32_to_cpu(ex->ee_block) + ee_len - 1) { 1941 /* tail removal */ 1942 ext4_lblk_t num; 1943 ext4_fsblk_t start; 1944 1945 num = le32_to_cpu(ex->ee_block) + ee_len - from; 1946 start = ext_pblock(ex) + ee_len - num; 1947 ext_debug("free last %u blocks starting %llu\n", num, start); 1948 for (i = 0; i < num; i++) { 1949 bh = sb_find_get_block(inode->i_sb, start + i); 1950 ext4_forget(handle, 0, inode, bh, start + i); 1951 } 1952 ext4_free_blocks(handle, inode, start, num, metadata); 1953 } else if (from == le32_to_cpu(ex->ee_block) 1954 && to <= le32_to_cpu(ex->ee_block) + ee_len - 1) { 1955 printk(KERN_INFO "strange request: removal %u-%u from %u:%u\n", 1956 from, to, le32_to_cpu(ex->ee_block), ee_len); 1957 } else { 1958 printk(KERN_INFO "strange request: removal(2) " 1959 "%u-%u from %u:%u\n", 1960 from, to, le32_to_cpu(ex->ee_block), ee_len); 1961 } 1962 return 0; 1963} 1964 1965static int 1966ext4_ext_rm_leaf(handle_t *handle, struct inode *inode, 1967 struct ext4_ext_path *path, ext4_lblk_t start) 1968{ 1969 int err = 0, correct_index = 0; 1970 int depth = ext_depth(inode), credits; 1971 struct ext4_extent_header *eh; 1972 ext4_lblk_t a, b, block; 1973 unsigned num; 1974 ext4_lblk_t ex_ee_block; 1975 unsigned short ex_ee_len; 1976 unsigned uninitialized = 0; 1977 struct ext4_extent *ex; 1978 1979 /* the header must be checked already in ext4_ext_remove_space() */ 1980 ext_debug("truncate since %u in leaf\n", start); 1981 if (!path[depth].p_hdr) 1982 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh); 1983 eh = path[depth].p_hdr; 1984 BUG_ON(eh == NULL); 1985 1986 /* find where to start removing */ 1987 ex = EXT_LAST_EXTENT(eh); 1988 1989 ex_ee_block = le32_to_cpu(ex->ee_block); 1990 if (ext4_ext_is_uninitialized(ex)) 1991 uninitialized = 1; 1992 ex_ee_len = ext4_ext_get_actual_len(ex); 1993 1994 while (ex >= EXT_FIRST_EXTENT(eh) && 1995 ex_ee_block + ex_ee_len > start) { 1996 ext_debug("remove ext %lu:%u\n", ex_ee_block, ex_ee_len); 1997 path[depth].p_ext = ex; 1998 1999 a = ex_ee_block > start ? ex_ee_block : start; 2000 b = ex_ee_block + ex_ee_len - 1 < EXT_MAX_BLOCK ? 2001 ex_ee_block + ex_ee_len - 1 : EXT_MAX_BLOCK; 2002 2003 ext_debug(" border %u:%u\n", a, b); 2004 2005 if (a != ex_ee_block && b != ex_ee_block + ex_ee_len - 1) { 2006 block = 0; 2007 num = 0; 2008 BUG(); 2009 } else if (a != ex_ee_block) { 2010 /* remove tail of the extent */ 2011 block = ex_ee_block; 2012 num = a - block; 2013 } else if (b != ex_ee_block + ex_ee_len - 1) { 2014 /* remove head of the extent */ 2015 block = a; 2016 num = b - a; 2017 /* there is no "make a hole" API yet */ 2018 BUG(); 2019 } else { 2020 /* remove whole extent: excellent! */ 2021 block = ex_ee_block; 2022 num = 0; 2023 BUG_ON(a != ex_ee_block); 2024 BUG_ON(b != ex_ee_block + ex_ee_len - 1); 2025 } 2026 2027 /* 2028 * 3 for leaf, sb, and inode plus 2 (bmap and group 2029 * descriptor) for each block group; assume two block 2030 * groups plus ex_ee_len/blocks_per_block_group for 2031 * the worst case 2032 */ 2033 credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb)); 2034 if (ex == EXT_FIRST_EXTENT(eh)) { 2035 correct_index = 1; 2036 credits += (ext_depth(inode)) + 1; 2037 } 2038 credits += 2 * EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb); 2039 2040 err = ext4_ext_journal_restart(handle, credits); 2041 if (err) 2042 goto out; 2043 2044 err = ext4_ext_get_access(handle, inode, path + depth); 2045 if (err) 2046 goto out; 2047 2048 err = ext4_remove_blocks(handle, inode, ex, a, b); 2049 if (err) 2050 goto out; 2051 2052 if (num == 0) { 2053 /* this extent is removed; mark slot entirely unused */ 2054 ext4_ext_store_pblock(ex, 0); 2055 le16_add_cpu(&eh->eh_entries, -1); 2056 } 2057 2058 ex->ee_block = cpu_to_le32(block); 2059 ex->ee_len = cpu_to_le16(num); 2060 /* 2061 * Do not mark uninitialized if all the blocks in the 2062 * extent have been removed. 2063 */ 2064 if (uninitialized && num) 2065 ext4_ext_mark_uninitialized(ex); 2066 2067 err = ext4_ext_dirty(handle, inode, path + depth); 2068 if (err) 2069 goto out; 2070 2071 ext_debug("new extent: %u:%u:%llu\n", block, num, 2072 ext_pblock(ex)); 2073 ex--; 2074 ex_ee_block = le32_to_cpu(ex->ee_block); 2075 ex_ee_len = ext4_ext_get_actual_len(ex); 2076 } 2077 2078 if (correct_index && eh->eh_entries) 2079 err = ext4_ext_correct_indexes(handle, inode, path); 2080 2081 /* if this leaf is free, then we should 2082 * remove it from index block above */ 2083 if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL) 2084 err = ext4_ext_rm_idx(handle, inode, path + depth); 2085 2086out: 2087 return err; 2088} 2089 2090/* 2091 * ext4_ext_more_to_rm: 2092 * returns 1 if current index has to be freed (even partial) 2093 */ 2094static int 2095ext4_ext_more_to_rm(struct ext4_ext_path *path) 2096{ 2097 BUG_ON(path->p_idx == NULL); 2098 2099 if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr)) 2100 return 0; 2101 2102 /* 2103 * if truncate on deeper level happened, it wasn't partial, 2104 * so we have to consider current index for truncation 2105 */ 2106 if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block) 2107 return 0; 2108 return 1; 2109} 2110 2111static int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start) 2112{ 2113 struct super_block *sb = inode->i_sb; 2114 int depth = ext_depth(inode); 2115 struct ext4_ext_path *path; 2116 handle_t *handle; 2117 int i = 0, err = 0; 2118 2119 ext_debug("truncate since %u\n", start); 2120 2121 /* probably first extent we're gonna free will be last in block */ 2122 handle = ext4_journal_start(inode, depth + 1); 2123 if (IS_ERR(handle)) 2124 return PTR_ERR(handle); 2125 2126 ext4_ext_invalidate_cache(inode); 2127 2128 /* 2129 * We start scanning from right side, freeing all the blocks 2130 * after i_size and walking into the tree depth-wise. 2131 */ 2132 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1), GFP_NOFS); 2133 if (path == NULL) { 2134 ext4_journal_stop(handle); 2135 return -ENOMEM; 2136 } 2137 path[0].p_hdr = ext_inode_hdr(inode); 2138 if (ext4_ext_check_header(inode, path[0].p_hdr, depth)) { 2139 err = -EIO; 2140 goto out; 2141 } 2142 path[0].p_depth = depth; 2143 2144 while (i >= 0 && err == 0) { 2145 if (i == depth) { 2146 /* this is leaf block */ 2147 err = ext4_ext_rm_leaf(handle, inode, path, start); 2148 /* root level has p_bh == NULL, brelse() eats this */ 2149 brelse(path[i].p_bh); 2150 path[i].p_bh = NULL; 2151 i--; 2152 continue; 2153 } 2154 2155 /* this is index block */ 2156 if (!path[i].p_hdr) { 2157 ext_debug("initialize header\n"); 2158 path[i].p_hdr = ext_block_hdr(path[i].p_bh); 2159 } 2160 2161 if (!path[i].p_idx) { 2162 /* this level hasn't been touched yet */ 2163 path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr); 2164 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1; 2165 ext_debug("init index ptr: hdr 0x%p, num %d\n", 2166 path[i].p_hdr, 2167 le16_to_cpu(path[i].p_hdr->eh_entries)); 2168 } else { 2169 /* we were already here, see at next index */ 2170 path[i].p_idx--; 2171 } 2172 2173 ext_debug("level %d - index, first 0x%p, cur 0x%p\n", 2174 i, EXT_FIRST_INDEX(path[i].p_hdr), 2175 path[i].p_idx); 2176 if (ext4_ext_more_to_rm(path + i)) { 2177 struct buffer_head *bh; 2178 /* go to the next level */ 2179 ext_debug("move to level %d (block %llu)\n", 2180 i + 1, idx_pblock(path[i].p_idx)); 2181 memset(path + i + 1, 0, sizeof(*path)); 2182 bh = sb_bread(sb, idx_pblock(path[i].p_idx)); 2183 if (!bh) { 2184 /* should we reset i_size? */ 2185 err = -EIO; 2186 break; 2187 } 2188 if (WARN_ON(i + 1 > depth)) { 2189 err = -EIO; 2190 break; 2191 } 2192 if (ext4_ext_check_header(inode, ext_block_hdr(bh), 2193 depth - i - 1)) { 2194 err = -EIO; 2195 break; 2196 } 2197 path[i + 1].p_bh = bh; 2198 2199 /* save actual number of indexes since this 2200 * number is changed at the next iteration */ 2201 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries); 2202 i++; 2203 } else { 2204 /* we finished processing this index, go up */ 2205 if (path[i].p_hdr->eh_entries == 0 && i > 0) { 2206 /* index is empty, remove it; 2207 * handle must be already prepared by the 2208 * truncatei_leaf() */ 2209 err = ext4_ext_rm_idx(handle, inode, path + i); 2210 } 2211 /* root level has p_bh == NULL, brelse() eats this */ 2212 brelse(path[i].p_bh); 2213 path[i].p_bh = NULL; 2214 i--; 2215 ext_debug("return to level %d\n", i); 2216 } 2217 } 2218 2219 /* TODO: flexible tree reduction should be here */ 2220 if (path->p_hdr->eh_entries == 0) { 2221 /* 2222 * truncate to zero freed all the tree, 2223 * so we need to correct eh_depth 2224 */ 2225 err = ext4_ext_get_access(handle, inode, path); 2226 if (err == 0) { 2227 ext_inode_hdr(inode)->eh_depth = 0; 2228 ext_inode_hdr(inode)->eh_max = 2229 cpu_to_le16(ext4_ext_space_root(inode)); 2230 err = ext4_ext_dirty(handle, inode, path); 2231 } 2232 } 2233out: 2234 ext4_ext_drop_refs(path); 2235 kfree(path); 2236 ext4_journal_stop(handle); 2237 2238 return err; 2239} 2240 2241/* 2242 * called at mount time 2243 */ 2244void ext4_ext_init(struct super_block *sb) 2245{ 2246 /* 2247 * possible initialization would be here 2248 */ 2249 2250 if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) { 2251 printk(KERN_INFO "EXT4-fs: file extents enabled"); 2252#ifdef AGGRESSIVE_TEST 2253 printk(", aggressive tests"); 2254#endif 2255#ifdef CHECK_BINSEARCH 2256 printk(", check binsearch"); 2257#endif 2258#ifdef EXTENTS_STATS 2259 printk(", stats"); 2260#endif 2261 printk("\n"); 2262#ifdef EXTENTS_STATS 2263 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock); 2264 EXT4_SB(sb)->s_ext_min = 1 << 30; 2265 EXT4_SB(sb)->s_ext_max = 0; 2266#endif 2267 } 2268} 2269 2270/* 2271 * called at umount time 2272 */ 2273void ext4_ext_release(struct super_block *sb) 2274{ 2275 if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) 2276 return; 2277 2278#ifdef EXTENTS_STATS 2279 if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) { 2280 struct ext4_sb_info *sbi = EXT4_SB(sb); 2281 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n", 2282 sbi->s_ext_blocks, sbi->s_ext_extents, 2283 sbi->s_ext_blocks / sbi->s_ext_extents); 2284 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n", 2285 sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max); 2286 } 2287#endif 2288} 2289 2290static void bi_complete(struct bio *bio, int error) 2291{ 2292 complete((struct completion *)bio->bi_private); 2293} 2294 2295/* FIXME!! we need to try to merge to left or right after zero-out */ 2296static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex) 2297{ 2298 int ret = -EIO; 2299 struct bio *bio; 2300 int blkbits, blocksize; 2301 sector_t ee_pblock; 2302 struct completion event; 2303 unsigned int ee_len, len, done, offset; 2304 2305 2306 blkbits = inode->i_blkbits; 2307 blocksize = inode->i_sb->s_blocksize; 2308 ee_len = ext4_ext_get_actual_len(ex); 2309 ee_pblock = ext_pblock(ex); 2310 2311 /* convert ee_pblock to 512 byte sectors */ 2312 ee_pblock = ee_pblock << (blkbits - 9); 2313 2314 while (ee_len > 0) { 2315 2316 if (ee_len > BIO_MAX_PAGES) 2317 len = BIO_MAX_PAGES; 2318 else 2319 len = ee_len; 2320 2321 bio = bio_alloc(GFP_NOIO, len); 2322 if (!bio) 2323 return -ENOMEM; 2324 bio->bi_sector = ee_pblock; 2325 bio->bi_bdev = inode->i_sb->s_bdev; 2326 2327 done = 0; 2328 offset = 0; 2329 while (done < len) { 2330 ret = bio_add_page(bio, ZERO_PAGE(0), 2331 blocksize, offset); 2332 if (ret != blocksize) { 2333 /* 2334 * We can't add any more pages because of 2335 * hardware limitations. Start a new bio. 2336 */ 2337 break; 2338 } 2339 done++; 2340 offset += blocksize; 2341 if (offset >= PAGE_CACHE_SIZE) 2342 offset = 0; 2343 } 2344 2345 init_completion(&event); 2346 bio->bi_private = &event; 2347 bio->bi_end_io = bi_complete; 2348 submit_bio(WRITE, bio); 2349 wait_for_completion(&event); 2350 2351 if (test_bit(BIO_UPTODATE, &bio->bi_flags)) 2352 ret = 0; 2353 else { 2354 ret = -EIO; 2355 break; 2356 } 2357 bio_put(bio); 2358 ee_len -= done; 2359 ee_pblock += done << (blkbits - 9); 2360 } 2361 return ret; 2362} 2363 2364#define EXT4_EXT_ZERO_LEN 7 2365 2366/* 2367 * This function is called by ext4_ext_get_blocks() if someone tries to write 2368 * to an uninitialized extent. It may result in splitting the uninitialized 2369 * extent into multiple extents (upto three - one initialized and two 2370 * uninitialized). 2371 * There are three possibilities: 2372 * a> There is no split required: Entire extent should be initialized 2373 * b> Splits in two extents: Write is happening at either end of the extent 2374 * c> Splits in three extents: Somone is writing in middle of the extent 2375 */ 2376static int ext4_ext_convert_to_initialized(handle_t *handle, 2377 struct inode *inode, 2378 struct ext4_ext_path *path, 2379 ext4_lblk_t iblock, 2380 unsigned int max_blocks) 2381{ 2382 struct ext4_extent *ex, newex, orig_ex; 2383 struct ext4_extent *ex1 = NULL; 2384 struct ext4_extent *ex2 = NULL; 2385 struct ext4_extent *ex3 = NULL; 2386 struct ext4_extent_header *eh; 2387 ext4_lblk_t ee_block; 2388 unsigned int allocated, ee_len, depth; 2389 ext4_fsblk_t newblock; 2390 int err = 0; 2391 int ret = 0; 2392 2393 depth = ext_depth(inode); 2394 eh = path[depth].p_hdr; 2395 ex = path[depth].p_ext; 2396 ee_block = le32_to_cpu(ex->ee_block); 2397 ee_len = ext4_ext_get_actual_len(ex); 2398 allocated = ee_len - (iblock - ee_block); 2399 newblock = iblock - ee_block + ext_pblock(ex); 2400 ex2 = ex; 2401 orig_ex.ee_block = ex->ee_block; 2402 orig_ex.ee_len = cpu_to_le16(ee_len); 2403 ext4_ext_store_pblock(&orig_ex, ext_pblock(ex)); 2404 2405 err = ext4_ext_get_access(handle, inode, path + depth); 2406 if (err) 2407 goto out; 2408 /* If extent has less than 2*EXT4_EXT_ZERO_LEN zerout directly */ 2409 if (ee_len <= 2*EXT4_EXT_ZERO_LEN) { 2410 err = ext4_ext_zeroout(inode, &orig_ex); 2411 if (err) 2412 goto fix_extent_len; 2413 /* update the extent length and mark as initialized */ 2414 ex->ee_block = orig_ex.ee_block; 2415 ex->ee_len = orig_ex.ee_len; 2416 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2417 ext4_ext_dirty(handle, inode, path + depth); 2418 /* zeroed the full extent */ 2419 return allocated; 2420 } 2421 2422 /* ex1: ee_block to iblock - 1 : uninitialized */ 2423 if (iblock > ee_block) { 2424 ex1 = ex; 2425 ex1->ee_len = cpu_to_le16(iblock - ee_block); 2426 ext4_ext_mark_uninitialized(ex1); 2427 ex2 = &newex; 2428 } 2429 /* 2430 * for sanity, update the length of the ex2 extent before 2431 * we insert ex3, if ex1 is NULL. This is to avoid temporary 2432 * overlap of blocks. 2433 */ 2434 if (!ex1 && allocated > max_blocks) 2435 ex2->ee_len = cpu_to_le16(max_blocks); 2436 /* ex3: to ee_block + ee_len : uninitialised */ 2437 if (allocated > max_blocks) { 2438 unsigned int newdepth; 2439 /* If extent has less than EXT4_EXT_ZERO_LEN zerout directly */ 2440 if (allocated <= EXT4_EXT_ZERO_LEN) { 2441 /* 2442 * iblock == ee_block is handled by the zerouout 2443 * at the beginning. 2444 * Mark first half uninitialized. 2445 * Mark second half initialized and zero out the 2446 * initialized extent 2447 */ 2448 ex->ee_block = orig_ex.ee_block; 2449 ex->ee_len = cpu_to_le16(ee_len - allocated); 2450 ext4_ext_mark_uninitialized(ex); 2451 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2452 ext4_ext_dirty(handle, inode, path + depth); 2453 2454 ex3 = &newex; 2455 ex3->ee_block = cpu_to_le32(iblock); 2456 ext4_ext_store_pblock(ex3, newblock); 2457 ex3->ee_len = cpu_to_le16(allocated); 2458 err = ext4_ext_insert_extent(handle, inode, path, ex3); 2459 if (err == -ENOSPC) { 2460 err = ext4_ext_zeroout(inode, &orig_ex); 2461 if (err) 2462 goto fix_extent_len; 2463 ex->ee_block = orig_ex.ee_block; 2464 ex->ee_len = orig_ex.ee_len; 2465 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2466 ext4_ext_dirty(handle, inode, path + depth); 2467 /* blocks available from iblock */ 2468 return allocated; 2469 2470 } else if (err) 2471 goto fix_extent_len; 2472 2473 /* 2474 * We need to zero out the second half because 2475 * an fallocate request can update file size and 2476 * converting the second half to initialized extent 2477 * implies that we can leak some junk data to user 2478 * space. 2479 */ 2480 err = ext4_ext_zeroout(inode, ex3); 2481 if (err) { 2482 /* 2483 * We should actually mark the 2484 * second half as uninit and return error 2485 * Insert would have changed the extent 2486 */ 2487 depth = ext_depth(inode); 2488 ext4_ext_drop_refs(path); 2489 path = ext4_ext_find_extent(inode, 2490 iblock, path); 2491 if (IS_ERR(path)) { 2492 err = PTR_ERR(path); 2493 return err; 2494 } 2495 /* get the second half extent details */ 2496 ex = path[depth].p_ext; 2497 err = ext4_ext_get_access(handle, inode, 2498 path + depth); 2499 if (err) 2500 return err; 2501 ext4_ext_mark_uninitialized(ex); 2502 ext4_ext_dirty(handle, inode, path + depth); 2503 return err; 2504 } 2505 2506 /* zeroed the second half */ 2507 return allocated; 2508 } 2509 ex3 = &newex; 2510 ex3->ee_block = cpu_to_le32(iblock + max_blocks); 2511 ext4_ext_store_pblock(ex3, newblock + max_blocks); 2512 ex3->ee_len = cpu_to_le16(allocated - max_blocks); 2513 ext4_ext_mark_uninitialized(ex3); 2514 err = ext4_ext_insert_extent(handle, inode, path, ex3); 2515 if (err == -ENOSPC) { 2516 err = ext4_ext_zeroout(inode, &orig_ex); 2517 if (err) 2518 goto fix_extent_len; 2519 /* update the extent length and mark as initialized */ 2520 ex->ee_block = orig_ex.ee_block; 2521 ex->ee_len = orig_ex.ee_len; 2522 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2523 ext4_ext_dirty(handle, inode, path + depth); 2524 /* zeroed the full extent */ 2525 /* blocks available from iblock */ 2526 return allocated; 2527 2528 } else if (err) 2529 goto fix_extent_len; 2530 /* 2531 * The depth, and hence eh & ex might change 2532 * as part of the insert above. 2533 */ 2534 newdepth = ext_depth(inode); 2535 /* 2536 * update the extent length after successful insert of the 2537 * split extent 2538 */ 2539 orig_ex.ee_len = cpu_to_le16(ee_len - 2540 ext4_ext_get_actual_len(ex3)); 2541 depth = newdepth; 2542 ext4_ext_drop_refs(path); 2543 path = ext4_ext_find_extent(inode, iblock, path); 2544 if (IS_ERR(path)) { 2545 err = PTR_ERR(path); 2546 goto out; 2547 } 2548 eh = path[depth].p_hdr; 2549 ex = path[depth].p_ext; 2550 if (ex2 != &newex) 2551 ex2 = ex; 2552 2553 err = ext4_ext_get_access(handle, inode, path + depth); 2554 if (err) 2555 goto out; 2556 2557 allocated = max_blocks; 2558 2559 /* If extent has less than EXT4_EXT_ZERO_LEN and we are trying 2560 * to insert a extent in the middle zerout directly 2561 * otherwise give the extent a chance to merge to left 2562 */ 2563 if (le16_to_cpu(orig_ex.ee_len) <= EXT4_EXT_ZERO_LEN && 2564 iblock != ee_block) { 2565 err = ext4_ext_zeroout(inode, &orig_ex); 2566 if (err) 2567 goto fix_extent_len; 2568 /* update the extent length and mark as initialized */ 2569 ex->ee_block = orig_ex.ee_block; 2570 ex->ee_len = orig_ex.ee_len; 2571 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2572 ext4_ext_dirty(handle, inode, path + depth); 2573 /* zero out the first half */ 2574 /* blocks available from iblock */ 2575 return allocated; 2576 } 2577 } 2578 /* 2579 * If there was a change of depth as part of the 2580 * insertion of ex3 above, we need to update the length 2581 * of the ex1 extent again here 2582 */ 2583 if (ex1 && ex1 != ex) { 2584 ex1 = ex; 2585 ex1->ee_len = cpu_to_le16(iblock - ee_block); 2586 ext4_ext_mark_uninitialized(ex1); 2587 ex2 = &newex; 2588 } 2589 /* ex2: iblock to iblock + maxblocks-1 : initialised */ 2590 ex2->ee_block = cpu_to_le32(iblock); 2591 ext4_ext_store_pblock(ex2, newblock); 2592 ex2->ee_len = cpu_to_le16(allocated); 2593 if (ex2 != ex) 2594 goto insert; 2595 /* 2596 * New (initialized) extent starts from the first block 2597 * in the current extent. i.e., ex2 == ex 2598 * We have to see if it can be merged with the extent 2599 * on the left. 2600 */ 2601 if (ex2 > EXT_FIRST_EXTENT(eh)) { 2602 /* 2603 * To merge left, pass "ex2 - 1" to try_to_merge(), 2604 * since it merges towards right _only_. 2605 */ 2606 ret = ext4_ext_try_to_merge(inode, path, ex2 - 1); 2607 if (ret) { 2608 err = ext4_ext_correct_indexes(handle, inode, path); 2609 if (err) 2610 goto out; 2611 depth = ext_depth(inode); 2612 ex2--; 2613 } 2614 } 2615 /* 2616 * Try to Merge towards right. This might be required 2617 * only when the whole extent is being written to. 2618 * i.e. ex2 == ex and ex3 == NULL. 2619 */ 2620 if (!ex3) { 2621 ret = ext4_ext_try_to_merge(inode, path, ex2); 2622 if (ret) { 2623 err = ext4_ext_correct_indexes(handle, inode, path); 2624 if (err) 2625 goto out; 2626 } 2627 } 2628 /* Mark modified extent as dirty */ 2629 err = ext4_ext_dirty(handle, inode, path + depth); 2630 goto out; 2631insert: 2632 err = ext4_ext_insert_extent(handle, inode, path, &newex); 2633 if (err == -ENOSPC) { 2634 err = ext4_ext_zeroout(inode, &orig_ex); 2635 if (err) 2636 goto fix_extent_len; 2637 /* update the extent length and mark as initialized */ 2638 ex->ee_block = orig_ex.ee_block; 2639 ex->ee_len = orig_ex.ee_len; 2640 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2641 ext4_ext_dirty(handle, inode, path + depth); 2642 /* zero out the first half */ 2643 return allocated; 2644 } else if (err) 2645 goto fix_extent_len; 2646out: 2647 return err ? err : allocated; 2648 2649fix_extent_len: 2650 ex->ee_block = orig_ex.ee_block; 2651 ex->ee_len = orig_ex.ee_len; 2652 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2653 ext4_ext_mark_uninitialized(ex); 2654 ext4_ext_dirty(handle, inode, path + depth); 2655 return err; 2656} 2657 2658/* 2659 * Block allocation/map/preallocation routine for extents based files 2660 * 2661 * 2662 * Need to be called with 2663 * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block 2664 * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem) 2665 * 2666 * return > 0, number of of blocks already mapped/allocated 2667 * if create == 0 and these are pre-allocated blocks 2668 * buffer head is unmapped 2669 * otherwise blocks are mapped 2670 * 2671 * return = 0, if plain look up failed (blocks have not been allocated) 2672 * buffer head is unmapped 2673 * 2674 * return < 0, error case. 2675 */ 2676int ext4_ext_get_blocks(handle_t *handle, struct inode *inode, 2677 ext4_lblk_t iblock, 2678 unsigned int max_blocks, struct buffer_head *bh_result, 2679 int create, int extend_disksize) 2680{ 2681 struct ext4_ext_path *path = NULL; 2682 struct ext4_extent_header *eh; 2683 struct ext4_extent newex, *ex; 2684 ext4_fsblk_t newblock; 2685 int err = 0, depth, ret, cache_type; 2686 unsigned int allocated = 0; 2687 struct ext4_allocation_request ar; 2688 loff_t disksize; 2689 2690 __clear_bit(BH_New, &bh_result->b_state); 2691 ext_debug("blocks %u/%u requested for inode %u\n", 2692 iblock, max_blocks, inode->i_ino); 2693 2694 /* check in cache */ 2695 cache_type = ext4_ext_in_cache(inode, iblock, &newex); 2696 if (cache_type) { 2697 if (cache_type == EXT4_EXT_CACHE_GAP) { 2698 if (!create) { 2699 /* 2700 * block isn't allocated yet and 2701 * user doesn't want to allocate it 2702 */ 2703 goto out2; 2704 } 2705 /* we should allocate requested block */ 2706 } else if (cache_type == EXT4_EXT_CACHE_EXTENT) { 2707 /* block is already allocated */ 2708 newblock = iblock 2709 - le32_to_cpu(newex.ee_block) 2710 + ext_pblock(&newex); 2711 /* number of remaining blocks in the extent */ 2712 allocated = ext4_ext_get_actual_len(&newex) - 2713 (iblock - le32_to_cpu(newex.ee_block)); 2714 goto out; 2715 } else { 2716 BUG(); 2717 } 2718 } 2719 2720 /* find extent for this block */ 2721 path = ext4_ext_find_extent(inode, iblock, NULL); 2722 if (IS_ERR(path)) { 2723 err = PTR_ERR(path); 2724 path = NULL; 2725 goto out2; 2726 } 2727 2728 depth = ext_depth(inode); 2729 2730 /* 2731 * consistent leaf must not be empty; 2732 * this situation is possible, though, _during_ tree modification; 2733 * this is why assert can't be put in ext4_ext_find_extent() 2734 */ 2735 BUG_ON(path[depth].p_ext == NULL && depth != 0); 2736 eh = path[depth].p_hdr; 2737 2738 ex = path[depth].p_ext; 2739 if (ex) { 2740 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block); 2741 ext4_fsblk_t ee_start = ext_pblock(ex); 2742 unsigned short ee_len; 2743 2744 /* 2745 * Uninitialized extents are treated as holes, except that 2746 * we split out initialized portions during a write. 2747 */ 2748 ee_len = ext4_ext_get_actual_len(ex); 2749 /* if found extent covers block, simply return it */ 2750 if (iblock >= ee_block && iblock < ee_block + ee_len) { 2751 newblock = iblock - ee_block + ee_start; 2752 /* number of remaining blocks in the extent */ 2753 allocated = ee_len - (iblock - ee_block); 2754 ext_debug("%u fit into %lu:%d -> %llu\n", iblock, 2755 ee_block, ee_len, newblock); 2756 2757 /* Do not put uninitialized extent in the cache */ 2758 if (!ext4_ext_is_uninitialized(ex)) { 2759 ext4_ext_put_in_cache(inode, ee_block, 2760 ee_len, ee_start, 2761 EXT4_EXT_CACHE_EXTENT); 2762 goto out; 2763 } 2764 if (create == EXT4_CREATE_UNINITIALIZED_EXT) 2765 goto out; 2766 if (!create) { 2767 /* 2768 * We have blocks reserved already. We 2769 * return allocated blocks so that delalloc 2770 * won't do block reservation for us. But 2771 * the buffer head will be unmapped so that 2772 * a read from the block returns 0s. 2773 */ 2774 if (allocated > max_blocks) 2775 allocated = max_blocks; 2776 set_buffer_unwritten(bh_result); 2777 goto out2; 2778 } 2779 2780 ret = ext4_ext_convert_to_initialized(handle, inode, 2781 path, iblock, 2782 max_blocks); 2783 if (ret <= 0) { 2784 err = ret; 2785 goto out2; 2786 } else 2787 allocated = ret; 2788 goto outnew; 2789 } 2790 } 2791 2792 /* 2793 * requested block isn't allocated yet; 2794 * we couldn't try to create block if create flag is zero 2795 */ 2796 if (!create) { 2797 /* 2798 * put just found gap into cache to speed up 2799 * subsequent requests 2800 */ 2801 ext4_ext_put_gap_in_cache(inode, path, iblock); 2802 goto out2; 2803 } 2804 /* 2805 * Okay, we need to do block allocation. 2806 */ 2807 2808 /* find neighbour allocated blocks */ 2809 ar.lleft = iblock; 2810 err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft); 2811 if (err) 2812 goto out2; 2813 ar.lright = iblock; 2814 err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright); 2815 if (err) 2816 goto out2; 2817 2818 /* 2819 * See if request is beyond maximum number of blocks we can have in 2820 * a single extent. For an initialized extent this limit is 2821 * EXT_INIT_MAX_LEN and for an uninitialized extent this limit is 2822 * EXT_UNINIT_MAX_LEN. 2823 */ 2824 if (max_blocks > EXT_INIT_MAX_LEN && 2825 create != EXT4_CREATE_UNINITIALIZED_EXT) 2826 max_blocks = EXT_INIT_MAX_LEN; 2827 else if (max_blocks > EXT_UNINIT_MAX_LEN && 2828 create == EXT4_CREATE_UNINITIALIZED_EXT) 2829 max_blocks = EXT_UNINIT_MAX_LEN; 2830 2831 /* Check if we can really insert (iblock)::(iblock+max_blocks) extent */ 2832 newex.ee_block = cpu_to_le32(iblock); 2833 newex.ee_len = cpu_to_le16(max_blocks); 2834 err = ext4_ext_check_overlap(inode, &newex, path); 2835 if (err) 2836 allocated = ext4_ext_get_actual_len(&newex); 2837 else 2838 allocated = max_blocks; 2839 2840 /* allocate new block */ 2841 ar.inode = inode; 2842 ar.goal = ext4_ext_find_goal(inode, path, iblock); 2843 ar.logical = iblock; 2844 ar.len = allocated; 2845 if (S_ISREG(inode->i_mode)) 2846 ar.flags = EXT4_MB_HINT_DATA; 2847 else 2848 /* disable in-core preallocation for non-regular files */ 2849 ar.flags = 0; 2850 newblock = ext4_mb_new_blocks(handle, &ar, &err); 2851 if (!newblock) 2852 goto out2; 2853 ext_debug("allocate new block: goal %llu, found %llu/%lu\n", 2854 ar.goal, newblock, allocated); 2855 2856 /* try to insert new extent into found leaf and return */ 2857 ext4_ext_store_pblock(&newex, newblock); 2858 newex.ee_len = cpu_to_le16(ar.len); 2859 if (create == EXT4_CREATE_UNINITIALIZED_EXT) /* Mark uninitialized */ 2860 ext4_ext_mark_uninitialized(&newex); 2861 err = ext4_ext_insert_extent(handle, inode, path, &newex); 2862 if (err) { 2863 /* free data blocks we just allocated */ 2864 /* not a good idea to call discard here directly, 2865 * but otherwise we'd need to call it every free() */ 2866 ext4_discard_preallocations(inode); 2867 ext4_free_blocks(handle, inode, ext_pblock(&newex), 2868 ext4_ext_get_actual_len(&newex), 0); 2869 goto out2; 2870 } 2871 2872 /* previous routine could use block we allocated */ 2873 newblock = ext_pblock(&newex); 2874 allocated = ext4_ext_get_actual_len(&newex); 2875outnew: 2876 if (extend_disksize) { 2877 disksize = ((loff_t) iblock + ar.len) << inode->i_blkbits; 2878 if (disksize > i_size_read(inode)) 2879 disksize = i_size_read(inode); 2880 if (disksize > EXT4_I(inode)->i_disksize) 2881 EXT4_I(inode)->i_disksize = disksize; 2882 } 2883 2884 set_buffer_new(bh_result); 2885 2886 /* Cache only when it is _not_ an uninitialized extent */ 2887 if (create != EXT4_CREATE_UNINITIALIZED_EXT) 2888 ext4_ext_put_in_cache(inode, iblock, allocated, newblock, 2889 EXT4_EXT_CACHE_EXTENT); 2890out: 2891 if (allocated > max_blocks) 2892 allocated = max_blocks; 2893 ext4_ext_show_leaf(inode, path); 2894 set_buffer_mapped(bh_result); 2895 bh_result->b_bdev = inode->i_sb->s_bdev; 2896 bh_result->b_blocknr = newblock; 2897out2: 2898 if (path) { 2899 ext4_ext_drop_refs(path); 2900 kfree(path); 2901 } 2902 return err ? err : allocated; 2903} 2904 2905void ext4_ext_truncate(struct inode *inode) 2906{ 2907 struct address_space *mapping = inode->i_mapping; 2908 struct super_block *sb = inode->i_sb; 2909 ext4_lblk_t last_block; 2910 handle_t *handle; 2911 int err = 0; 2912 2913 /* 2914 * probably first extent we're gonna free will be last in block 2915 */ 2916 err = ext4_writepage_trans_blocks(inode); 2917 handle = ext4_journal_start(inode, err); 2918 if (IS_ERR(handle)) 2919 return; 2920 2921 if (inode->i_size & (sb->s_blocksize - 1)) 2922 ext4_block_truncate_page(handle, mapping, inode->i_size); 2923 2924 if (ext4_orphan_add(handle, inode)) 2925 goto out_stop; 2926 2927 down_write(&EXT4_I(inode)->i_data_sem); 2928 ext4_ext_invalidate_cache(inode); 2929 2930 ext4_discard_preallocations(inode); 2931 2932 /* 2933 * TODO: optimization is possible here. 2934 * Probably we need not scan at all, 2935 * because page truncation is enough. 2936 */ 2937 2938 /* we have to know where to truncate from in crash case */ 2939 EXT4_I(inode)->i_disksize = inode->i_size; 2940 ext4_mark_inode_dirty(handle, inode); 2941 2942 last_block = (inode->i_size + sb->s_blocksize - 1) 2943 >> EXT4_BLOCK_SIZE_BITS(sb); 2944 err = ext4_ext_remove_space(inode, last_block); 2945 2946 /* In a multi-transaction truncate, we only make the final 2947 * transaction synchronous. 2948 */ 2949 if (IS_SYNC(inode)) 2950 ext4_handle_sync(handle); 2951 2952out_stop: 2953 up_write(&EXT4_I(inode)->i_data_sem); 2954 /* 2955 * If this was a simple ftruncate() and the file will remain alive, 2956 * then we need to clear up the orphan record which we created above. 2957 * However, if this was a real unlink then we were called by 2958 * ext4_delete_inode(), and we allow that function to clean up the 2959 * orphan info for us. 2960 */ 2961 if (inode->i_nlink) 2962 ext4_orphan_del(handle, inode); 2963 2964 inode->i_mtime = inode->i_ctime = ext4_current_time(inode); 2965 ext4_mark_inode_dirty(handle, inode); 2966 ext4_journal_stop(handle); 2967} 2968 2969static void ext4_falloc_update_inode(struct inode *inode, 2970 int mode, loff_t new_size, int update_ctime) 2971{ 2972 struct timespec now; 2973 2974 if (update_ctime) { 2975 now = current_fs_time(inode->i_sb); 2976 if (!timespec_equal(&inode->i_ctime, &now)) 2977 inode->i_ctime = now; 2978 } 2979 /* 2980 * Update only when preallocation was requested beyond 2981 * the file size. 2982 */ 2983 if (!(mode & FALLOC_FL_KEEP_SIZE)) { 2984 if (new_size > i_size_read(inode)) 2985 i_size_write(inode, new_size); 2986 if (new_size > EXT4_I(inode)->i_disksize) 2987 ext4_update_i_disksize(inode, new_size); 2988 } 2989 2990} 2991 2992/* 2993 * preallocate space for a file. This implements ext4's fallocate inode 2994 * operation, which gets called from sys_fallocate system call. 2995 * For block-mapped files, posix_fallocate should fall back to the method 2996 * of writing zeroes to the required new blocks (the same behavior which is 2997 * expected for file systems which do not support fallocate() system call). 2998 */ 2999long ext4_fallocate(struct inode *inode, int mode, loff_t offset, loff_t len) 3000{ 3001 handle_t *handle; 3002 ext4_lblk_t block; 3003 loff_t new_size; 3004 unsigned int max_blocks; 3005 int ret = 0; 3006 int ret2 = 0; 3007 int retries = 0; 3008 struct buffer_head map_bh; 3009 unsigned int credits, blkbits = inode->i_blkbits; 3010 3011 /* 3012 * currently supporting (pre)allocate mode for extent-based 3013 * files _only_ 3014 */ 3015 if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) 3016 return -EOPNOTSUPP; 3017 3018 /* preallocation to directories is currently not supported */ 3019 if (S_ISDIR(inode->i_mode)) 3020 return -ENODEV; 3021 3022 block = offset >> blkbits; 3023 /* 3024 * We can't just convert len to max_blocks because 3025 * If blocksize = 4096 offset = 3072 and len = 2048 3026 */ 3027 max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits) 3028 - block; 3029 /* 3030 * credits to insert 1 extent into extent tree 3031 */ 3032 credits = ext4_chunk_trans_blocks(inode, max_blocks); 3033 mutex_lock(&inode->i_mutex); 3034retry: 3035 while (ret >= 0 && ret < max_blocks) { 3036 block = block + ret; 3037 max_blocks = max_blocks - ret; 3038 handle = ext4_journal_start(inode, credits); 3039 if (IS_ERR(handle)) { 3040 ret = PTR_ERR(handle); 3041 break; 3042 } 3043 ret = ext4_get_blocks_wrap(handle, inode, block, 3044 max_blocks, &map_bh, 3045 EXT4_CREATE_UNINITIALIZED_EXT, 0, 0); 3046 if (ret <= 0) { 3047#ifdef EXT4FS_DEBUG 3048 WARN_ON(ret <= 0); 3049 printk(KERN_ERR "%s: ext4_ext_get_blocks " 3050 "returned error inode#%lu, block=%u, " 3051 "max_blocks=%u", __func__, 3052 inode->i_ino, block, max_blocks); 3053#endif 3054 ext4_mark_inode_dirty(handle, inode); 3055 ret2 = ext4_journal_stop(handle); 3056 break; 3057 } 3058 if ((block + ret) >= (EXT4_BLOCK_ALIGN(offset + len, 3059 blkbits) >> blkbits)) 3060 new_size = offset + len; 3061 else 3062 new_size = (block + ret) << blkbits; 3063 3064 ext4_falloc_update_inode(inode, mode, new_size, 3065 buffer_new(&map_bh)); 3066 ext4_mark_inode_dirty(handle, inode); 3067 ret2 = ext4_journal_stop(handle); 3068 if (ret2) 3069 break; 3070 } 3071 if (ret == -ENOSPC && 3072 ext4_should_retry_alloc(inode->i_sb, &retries)) { 3073 ret = 0; 3074 goto retry; 3075 } 3076 mutex_unlock(&inode->i_mutex); 3077 return ret > 0 ? ret2 : ret; 3078} 3079 3080/* 3081 * Callback function called for each extent to gather FIEMAP information. 3082 */ 3083static int ext4_ext_fiemap_cb(struct inode *inode, struct ext4_ext_path *path, 3084 struct ext4_ext_cache *newex, struct ext4_extent *ex, 3085 void *data) 3086{ 3087 struct fiemap_extent_info *fieinfo = data; 3088 unsigned long blksize_bits = inode->i_sb->s_blocksize_bits; 3089 __u64 logical; 3090 __u64 physical; 3091 __u64 length; 3092 __u32 flags = 0; 3093 int error; 3094 3095 logical = (__u64)newex->ec_block << blksize_bits; 3096 3097 if (newex->ec_type == EXT4_EXT_CACHE_GAP) { 3098 pgoff_t offset; 3099 struct page *page; 3100 struct buffer_head *bh = NULL; 3101 3102 offset = logical >> PAGE_SHIFT; 3103 page = find_get_page(inode->i_mapping, offset); 3104 if (!page || !page_has_buffers(page)) 3105 return EXT_CONTINUE; 3106 3107 bh = page_buffers(page); 3108 3109 if (!bh) 3110 return EXT_CONTINUE; 3111 3112 if (buffer_delay(bh)) { 3113 flags |= FIEMAP_EXTENT_DELALLOC; 3114 page_cache_release(page); 3115 } else { 3116 page_cache_release(page); 3117 return EXT_CONTINUE; 3118 } 3119 } 3120 3121 physical = (__u64)newex->ec_start << blksize_bits; 3122 length = (__u64)newex->ec_len << blksize_bits; 3123 3124 if (ex && ext4_ext_is_uninitialized(ex)) 3125 flags |= FIEMAP_EXTENT_UNWRITTEN; 3126 3127 /* 3128 * If this extent reaches EXT_MAX_BLOCK, it must be last. 3129 * 3130 * Or if ext4_ext_next_allocated_block is EXT_MAX_BLOCK, 3131 * this also indicates no more allocated blocks. 3132 * 3133 * XXX this might miss a single-block extent at EXT_MAX_BLOCK 3134 */ 3135 if (logical + length - 1 == EXT_MAX_BLOCK || 3136 ext4_ext_next_allocated_block(path) == EXT_MAX_BLOCK) 3137 flags |= FIEMAP_EXTENT_LAST; 3138 3139 error = fiemap_fill_next_extent(fieinfo, logical, physical, 3140 length, flags); 3141 if (error < 0) 3142 return error; 3143 if (error == 1) 3144 return EXT_BREAK; 3145 3146 return EXT_CONTINUE; 3147} 3148 3149/* fiemap flags we can handle specified here */ 3150#define EXT4_FIEMAP_FLAGS (FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR) 3151 3152static int ext4_xattr_fiemap(struct inode *inode, 3153 struct fiemap_extent_info *fieinfo) 3154{ 3155 __u64 physical = 0; 3156 __u64 length; 3157 __u32 flags = FIEMAP_EXTENT_LAST; 3158 int blockbits = inode->i_sb->s_blocksize_bits; 3159 int error = 0; 3160 3161 /* in-inode? */ 3162 if (EXT4_I(inode)->i_state & EXT4_STATE_XATTR) { 3163 struct ext4_iloc iloc; 3164 int offset; /* offset of xattr in inode */ 3165 3166 error = ext4_get_inode_loc(inode, &iloc); 3167 if (error) 3168 return error; 3169 physical = iloc.bh->b_blocknr << blockbits; 3170 offset = EXT4_GOOD_OLD_INODE_SIZE + 3171 EXT4_I(inode)->i_extra_isize; 3172 physical += offset; 3173 length = EXT4_SB(inode->i_sb)->s_inode_size - offset; 3174 flags |= FIEMAP_EXTENT_DATA_INLINE; 3175 } else { /* external block */ 3176 physical = EXT4_I(inode)->i_file_acl << blockbits; 3177 length = inode->i_sb->s_blocksize; 3178 } 3179 3180 if (physical) 3181 error = fiemap_fill_next_extent(fieinfo, 0, physical, 3182 length, flags); 3183 return (error < 0 ? error : 0); 3184} 3185 3186int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, 3187 __u64 start, __u64 len) 3188{ 3189 ext4_lblk_t start_blk; 3190 ext4_lblk_t len_blks; 3191 int error = 0; 3192 3193 /* fallback to generic here if not in extents fmt */ 3194 if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) 3195 return generic_block_fiemap(inode, fieinfo, start, len, 3196 ext4_get_block); 3197 3198 if (fiemap_check_flags(fieinfo, EXT4_FIEMAP_FLAGS)) 3199 return -EBADR; 3200 3201 if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) { 3202 error = ext4_xattr_fiemap(inode, fieinfo); 3203 } else { 3204 start_blk = start >> inode->i_sb->s_blocksize_bits; 3205 len_blks = len >> inode->i_sb->s_blocksize_bits; 3206 3207 /* 3208 * Walk the extent tree gathering extent information. 3209 * ext4_ext_fiemap_cb will push extents back to user. 3210 */ 3211 down_write(&EXT4_I(inode)->i_data_sem); 3212 error = ext4_ext_walk_space(inode, start_blk, len_blks, 3213 ext4_ext_fiemap_cb, fieinfo); 3214 up_write(&EXT4_I(inode)->i_data_sem); 3215 } 3216 3217 return error; 3218} 3219 3220