extents.c revision c2ea3fde61f1df1dbf062345f23277dcd6f01dfe
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 "ext4_jbd2.h" 44#include "ext4_extents.h" 45 46 47/* 48 * ext_pblock: 49 * combine low and high parts of physical block number into ext4_fsblk_t 50 */ 51static ext4_fsblk_t ext_pblock(struct ext4_extent *ex) 52{ 53 ext4_fsblk_t block; 54 55 block = le32_to_cpu(ex->ee_start_lo); 56 block |= ((ext4_fsblk_t) le16_to_cpu(ex->ee_start_hi) << 31) << 1; 57 return block; 58} 59 60/* 61 * idx_pblock: 62 * combine low and high parts of a leaf physical block number into ext4_fsblk_t 63 */ 64ext4_fsblk_t idx_pblock(struct ext4_extent_idx *ix) 65{ 66 ext4_fsblk_t block; 67 68 block = le32_to_cpu(ix->ei_leaf_lo); 69 block |= ((ext4_fsblk_t) le16_to_cpu(ix->ei_leaf_hi) << 31) << 1; 70 return block; 71} 72 73/* 74 * ext4_ext_store_pblock: 75 * stores a large physical block number into an extent struct, 76 * breaking it into parts 77 */ 78void ext4_ext_store_pblock(struct ext4_extent *ex, ext4_fsblk_t pb) 79{ 80 ex->ee_start_lo = cpu_to_le32((unsigned long) (pb & 0xffffffff)); 81 ex->ee_start_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) & 0xffff); 82} 83 84/* 85 * ext4_idx_store_pblock: 86 * stores a large physical block number into an index struct, 87 * breaking it into parts 88 */ 89static void ext4_idx_store_pblock(struct ext4_extent_idx *ix, ext4_fsblk_t pb) 90{ 91 ix->ei_leaf_lo = cpu_to_le32((unsigned long) (pb & 0xffffffff)); 92 ix->ei_leaf_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) & 0xffff); 93} 94 95static int ext4_ext_journal_restart(handle_t *handle, int needed) 96{ 97 int err; 98 99 if (handle->h_buffer_credits > needed) 100 return 0; 101 err = ext4_journal_extend(handle, needed); 102 if (err <= 0) 103 return err; 104 return ext4_journal_restart(handle, needed); 105} 106 107/* 108 * could return: 109 * - EROFS 110 * - ENOMEM 111 */ 112static int ext4_ext_get_access(handle_t *handle, struct inode *inode, 113 struct ext4_ext_path *path) 114{ 115 if (path->p_bh) { 116 /* path points to block */ 117 return ext4_journal_get_write_access(handle, path->p_bh); 118 } 119 /* path points to leaf/index in inode body */ 120 /* we use in-core data, no need to protect them */ 121 return 0; 122} 123 124/* 125 * could return: 126 * - EROFS 127 * - ENOMEM 128 * - EIO 129 */ 130static int ext4_ext_dirty(handle_t *handle, struct inode *inode, 131 struct ext4_ext_path *path) 132{ 133 int err; 134 if (path->p_bh) { 135 /* path points to block */ 136 err = ext4_journal_dirty_metadata(handle, path->p_bh); 137 } else { 138 /* path points to leaf/index in inode body */ 139 err = ext4_mark_inode_dirty(handle, inode); 140 } 141 return err; 142} 143 144static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode, 145 struct ext4_ext_path *path, 146 ext4_lblk_t block) 147{ 148 struct ext4_inode_info *ei = EXT4_I(inode); 149 ext4_fsblk_t bg_start; 150 ext4_fsblk_t last_block; 151 ext4_grpblk_t colour; 152 int depth; 153 154 if (path) { 155 struct ext4_extent *ex; 156 depth = path->p_depth; 157 158 /* try to predict block placement */ 159 ex = path[depth].p_ext; 160 if (ex) 161 return ext_pblock(ex)+(block-le32_to_cpu(ex->ee_block)); 162 163 /* it looks like index is empty; 164 * try to find starting block from index itself */ 165 if (path[depth].p_bh) 166 return path[depth].p_bh->b_blocknr; 167 } 168 169 /* OK. use inode's group */ 170 bg_start = (ei->i_block_group * EXT4_BLOCKS_PER_GROUP(inode->i_sb)) + 171 le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_first_data_block); 172 last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1; 173 174 if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block) 175 colour = (current->pid % 16) * 176 (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16); 177 else 178 colour = (current->pid % 16) * ((last_block - bg_start) / 16); 179 return bg_start + colour + block; 180} 181 182/* 183 * Allocation for a meta data block 184 */ 185static ext4_fsblk_t 186ext4_ext_new_meta_block(handle_t *handle, struct inode *inode, 187 struct ext4_ext_path *path, 188 struct ext4_extent *ex, int *err) 189{ 190 ext4_fsblk_t goal, newblock; 191 192 goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block)); 193 newblock = ext4_new_meta_block(handle, inode, goal, err); 194 return newblock; 195} 196 197static int ext4_ext_space_block(struct inode *inode) 198{ 199 int size; 200 201 size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header)) 202 / sizeof(struct ext4_extent); 203#ifdef AGGRESSIVE_TEST 204 if (size > 6) 205 size = 6; 206#endif 207 return size; 208} 209 210static int ext4_ext_space_block_idx(struct inode *inode) 211{ 212 int size; 213 214 size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header)) 215 / sizeof(struct ext4_extent_idx); 216#ifdef AGGRESSIVE_TEST 217 if (size > 5) 218 size = 5; 219#endif 220 return size; 221} 222 223static int ext4_ext_space_root(struct inode *inode) 224{ 225 int size; 226 227 size = sizeof(EXT4_I(inode)->i_data); 228 size -= sizeof(struct ext4_extent_header); 229 size /= sizeof(struct ext4_extent); 230#ifdef AGGRESSIVE_TEST 231 if (size > 3) 232 size = 3; 233#endif 234 return size; 235} 236 237static int ext4_ext_space_root_idx(struct inode *inode) 238{ 239 int size; 240 241 size = sizeof(EXT4_I(inode)->i_data); 242 size -= sizeof(struct ext4_extent_header); 243 size /= sizeof(struct ext4_extent_idx); 244#ifdef AGGRESSIVE_TEST 245 if (size > 4) 246 size = 4; 247#endif 248 return size; 249} 250 251/* 252 * Calculate the number of metadata blocks needed 253 * to allocate @blocks 254 * Worse case is one block per extent 255 */ 256int ext4_ext_calc_metadata_amount(struct inode *inode, int blocks) 257{ 258 int lcap, icap, rcap, leafs, idxs, num; 259 int newextents = blocks; 260 261 rcap = ext4_ext_space_root_idx(inode); 262 lcap = ext4_ext_space_block(inode); 263 icap = ext4_ext_space_block_idx(inode); 264 265 /* number of new leaf blocks needed */ 266 num = leafs = (newextents + lcap - 1) / lcap; 267 268 /* 269 * Worse case, we need separate index block(s) 270 * to link all new leaf blocks 271 */ 272 idxs = (leafs + icap - 1) / icap; 273 do { 274 num += idxs; 275 idxs = (idxs + icap - 1) / icap; 276 } while (idxs > rcap); 277 278 return num; 279} 280 281static int 282ext4_ext_max_entries(struct inode *inode, int depth) 283{ 284 int max; 285 286 if (depth == ext_depth(inode)) { 287 if (depth == 0) 288 max = ext4_ext_space_root(inode); 289 else 290 max = ext4_ext_space_root_idx(inode); 291 } else { 292 if (depth == 0) 293 max = ext4_ext_space_block(inode); 294 else 295 max = ext4_ext_space_block_idx(inode); 296 } 297 298 return max; 299} 300 301static int __ext4_ext_check_header(const char *function, struct inode *inode, 302 struct ext4_extent_header *eh, 303 int depth) 304{ 305 const char *error_msg; 306 int max = 0; 307 308 if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) { 309 error_msg = "invalid magic"; 310 goto corrupted; 311 } 312 if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) { 313 error_msg = "unexpected eh_depth"; 314 goto corrupted; 315 } 316 if (unlikely(eh->eh_max == 0)) { 317 error_msg = "invalid eh_max"; 318 goto corrupted; 319 } 320 max = ext4_ext_max_entries(inode, depth); 321 if (unlikely(le16_to_cpu(eh->eh_max) > max)) { 322 error_msg = "too large eh_max"; 323 goto corrupted; 324 } 325 if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) { 326 error_msg = "invalid eh_entries"; 327 goto corrupted; 328 } 329 return 0; 330 331corrupted: 332 ext4_error(inode->i_sb, function, 333 "bad header in inode #%lu: %s - magic %x, " 334 "entries %u, max %u(%u), depth %u(%u)", 335 inode->i_ino, error_msg, le16_to_cpu(eh->eh_magic), 336 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max), 337 max, le16_to_cpu(eh->eh_depth), depth); 338 339 return -EIO; 340} 341 342#define ext4_ext_check_header(inode, eh, depth) \ 343 __ext4_ext_check_header(__func__, inode, eh, depth) 344 345#ifdef EXT_DEBUG 346static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path) 347{ 348 int k, l = path->p_depth; 349 350 ext_debug("path:"); 351 for (k = 0; k <= l; k++, path++) { 352 if (path->p_idx) { 353 ext_debug(" %d->%llu", le32_to_cpu(path->p_idx->ei_block), 354 idx_pblock(path->p_idx)); 355 } else if (path->p_ext) { 356 ext_debug(" %d:%d:%llu ", 357 le32_to_cpu(path->p_ext->ee_block), 358 ext4_ext_get_actual_len(path->p_ext), 359 ext_pblock(path->p_ext)); 360 } else 361 ext_debug(" []"); 362 } 363 ext_debug("\n"); 364} 365 366static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path) 367{ 368 int depth = ext_depth(inode); 369 struct ext4_extent_header *eh; 370 struct ext4_extent *ex; 371 int i; 372 373 if (!path) 374 return; 375 376 eh = path[depth].p_hdr; 377 ex = EXT_FIRST_EXTENT(eh); 378 379 for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) { 380 ext_debug("%d:%d:%llu ", le32_to_cpu(ex->ee_block), 381 ext4_ext_get_actual_len(ex), ext_pblock(ex)); 382 } 383 ext_debug("\n"); 384} 385#else 386#define ext4_ext_show_path(inode, path) 387#define ext4_ext_show_leaf(inode, path) 388#endif 389 390void ext4_ext_drop_refs(struct ext4_ext_path *path) 391{ 392 int depth = path->p_depth; 393 int i; 394 395 for (i = 0; i <= depth; i++, path++) 396 if (path->p_bh) { 397 brelse(path->p_bh); 398 path->p_bh = NULL; 399 } 400} 401 402/* 403 * ext4_ext_binsearch_idx: 404 * binary search for the closest index of the given block 405 * the header must be checked before calling this 406 */ 407static void 408ext4_ext_binsearch_idx(struct inode *inode, 409 struct ext4_ext_path *path, ext4_lblk_t block) 410{ 411 struct ext4_extent_header *eh = path->p_hdr; 412 struct ext4_extent_idx *r, *l, *m; 413 414 415 ext_debug("binsearch for %u(idx): ", block); 416 417 l = EXT_FIRST_INDEX(eh) + 1; 418 r = EXT_LAST_INDEX(eh); 419 while (l <= r) { 420 m = l + (r - l) / 2; 421 if (block < le32_to_cpu(m->ei_block)) 422 r = m - 1; 423 else 424 l = m + 1; 425 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ei_block), 426 m, le32_to_cpu(m->ei_block), 427 r, le32_to_cpu(r->ei_block)); 428 } 429 430 path->p_idx = l - 1; 431 ext_debug(" -> %d->%lld ", le32_to_cpu(path->p_idx->ei_block), 432 idx_pblock(path->p_idx)); 433 434#ifdef CHECK_BINSEARCH 435 { 436 struct ext4_extent_idx *chix, *ix; 437 int k; 438 439 chix = ix = EXT_FIRST_INDEX(eh); 440 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) { 441 if (k != 0 && 442 le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) { 443 printk(KERN_DEBUG "k=%d, ix=0x%p, " 444 "first=0x%p\n", k, 445 ix, EXT_FIRST_INDEX(eh)); 446 printk(KERN_DEBUG "%u <= %u\n", 447 le32_to_cpu(ix->ei_block), 448 le32_to_cpu(ix[-1].ei_block)); 449 } 450 BUG_ON(k && le32_to_cpu(ix->ei_block) 451 <= le32_to_cpu(ix[-1].ei_block)); 452 if (block < le32_to_cpu(ix->ei_block)) 453 break; 454 chix = ix; 455 } 456 BUG_ON(chix != path->p_idx); 457 } 458#endif 459 460} 461 462/* 463 * ext4_ext_binsearch: 464 * binary search for closest extent of the given block 465 * the header must be checked before calling this 466 */ 467static void 468ext4_ext_binsearch(struct inode *inode, 469 struct ext4_ext_path *path, ext4_lblk_t block) 470{ 471 struct ext4_extent_header *eh = path->p_hdr; 472 struct ext4_extent *r, *l, *m; 473 474 if (eh->eh_entries == 0) { 475 /* 476 * this leaf is empty: 477 * we get such a leaf in split/add case 478 */ 479 return; 480 } 481 482 ext_debug("binsearch for %u: ", block); 483 484 l = EXT_FIRST_EXTENT(eh) + 1; 485 r = EXT_LAST_EXTENT(eh); 486 487 while (l <= r) { 488 m = l + (r - l) / 2; 489 if (block < le32_to_cpu(m->ee_block)) 490 r = m - 1; 491 else 492 l = m + 1; 493 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ee_block), 494 m, le32_to_cpu(m->ee_block), 495 r, le32_to_cpu(r->ee_block)); 496 } 497 498 path->p_ext = l - 1; 499 ext_debug(" -> %d:%llu:%d ", 500 le32_to_cpu(path->p_ext->ee_block), 501 ext_pblock(path->p_ext), 502 ext4_ext_get_actual_len(path->p_ext)); 503 504#ifdef CHECK_BINSEARCH 505 { 506 struct ext4_extent *chex, *ex; 507 int k; 508 509 chex = ex = EXT_FIRST_EXTENT(eh); 510 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) { 511 BUG_ON(k && le32_to_cpu(ex->ee_block) 512 <= le32_to_cpu(ex[-1].ee_block)); 513 if (block < le32_to_cpu(ex->ee_block)) 514 break; 515 chex = ex; 516 } 517 BUG_ON(chex != path->p_ext); 518 } 519#endif 520 521} 522 523int ext4_ext_tree_init(handle_t *handle, struct inode *inode) 524{ 525 struct ext4_extent_header *eh; 526 527 eh = ext_inode_hdr(inode); 528 eh->eh_depth = 0; 529 eh->eh_entries = 0; 530 eh->eh_magic = EXT4_EXT_MAGIC; 531 eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode)); 532 ext4_mark_inode_dirty(handle, inode); 533 ext4_ext_invalidate_cache(inode); 534 return 0; 535} 536 537struct ext4_ext_path * 538ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block, 539 struct ext4_ext_path *path) 540{ 541 struct ext4_extent_header *eh; 542 struct buffer_head *bh; 543 short int depth, i, ppos = 0, alloc = 0; 544 545 eh = ext_inode_hdr(inode); 546 depth = ext_depth(inode); 547 if (ext4_ext_check_header(inode, eh, depth)) 548 return ERR_PTR(-EIO); 549 550 551 /* account possible depth increase */ 552 if (!path) { 553 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2), 554 GFP_NOFS); 555 if (!path) 556 return ERR_PTR(-ENOMEM); 557 alloc = 1; 558 } 559 path[0].p_hdr = eh; 560 path[0].p_bh = NULL; 561 562 i = depth; 563 /* walk through the tree */ 564 while (i) { 565 ext_debug("depth %d: num %d, max %d\n", 566 ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max)); 567 568 ext4_ext_binsearch_idx(inode, path + ppos, block); 569 path[ppos].p_block = idx_pblock(path[ppos].p_idx); 570 path[ppos].p_depth = i; 571 path[ppos].p_ext = NULL; 572 573 bh = sb_bread(inode->i_sb, path[ppos].p_block); 574 if (!bh) 575 goto err; 576 577 eh = ext_block_hdr(bh); 578 ppos++; 579 BUG_ON(ppos > depth); 580 path[ppos].p_bh = bh; 581 path[ppos].p_hdr = eh; 582 i--; 583 584 if (ext4_ext_check_header(inode, eh, i)) 585 goto err; 586 } 587 588 path[ppos].p_depth = i; 589 path[ppos].p_ext = NULL; 590 path[ppos].p_idx = NULL; 591 592 /* find extent */ 593 ext4_ext_binsearch(inode, path + ppos, block); 594 /* if not an empty leaf */ 595 if (path[ppos].p_ext) 596 path[ppos].p_block = ext_pblock(path[ppos].p_ext); 597 598 ext4_ext_show_path(inode, path); 599 600 return path; 601 602err: 603 ext4_ext_drop_refs(path); 604 if (alloc) 605 kfree(path); 606 return ERR_PTR(-EIO); 607} 608 609/* 610 * ext4_ext_insert_index: 611 * insert new index [@logical;@ptr] into the block at @curp; 612 * check where to insert: before @curp or after @curp 613 */ 614static int ext4_ext_insert_index(handle_t *handle, struct inode *inode, 615 struct ext4_ext_path *curp, 616 int logical, ext4_fsblk_t ptr) 617{ 618 struct ext4_extent_idx *ix; 619 int len, err; 620 621 err = ext4_ext_get_access(handle, inode, curp); 622 if (err) 623 return err; 624 625 BUG_ON(logical == le32_to_cpu(curp->p_idx->ei_block)); 626 len = EXT_MAX_INDEX(curp->p_hdr) - curp->p_idx; 627 if (logical > le32_to_cpu(curp->p_idx->ei_block)) { 628 /* insert after */ 629 if (curp->p_idx != EXT_LAST_INDEX(curp->p_hdr)) { 630 len = (len - 1) * sizeof(struct ext4_extent_idx); 631 len = len < 0 ? 0 : len; 632 ext_debug("insert new index %d after: %llu. " 633 "move %d from 0x%p to 0x%p\n", 634 logical, ptr, len, 635 (curp->p_idx + 1), (curp->p_idx + 2)); 636 memmove(curp->p_idx + 2, curp->p_idx + 1, len); 637 } 638 ix = curp->p_idx + 1; 639 } else { 640 /* insert before */ 641 len = len * sizeof(struct ext4_extent_idx); 642 len = len < 0 ? 0 : len; 643 ext_debug("insert new index %d before: %llu. " 644 "move %d from 0x%p to 0x%p\n", 645 logical, ptr, len, 646 curp->p_idx, (curp->p_idx + 1)); 647 memmove(curp->p_idx + 1, curp->p_idx, len); 648 ix = curp->p_idx; 649 } 650 651 ix->ei_block = cpu_to_le32(logical); 652 ext4_idx_store_pblock(ix, ptr); 653 le16_add_cpu(&curp->p_hdr->eh_entries, 1); 654 655 BUG_ON(le16_to_cpu(curp->p_hdr->eh_entries) 656 > le16_to_cpu(curp->p_hdr->eh_max)); 657 BUG_ON(ix > EXT_LAST_INDEX(curp->p_hdr)); 658 659 err = ext4_ext_dirty(handle, inode, curp); 660 ext4_std_error(inode->i_sb, err); 661 662 return err; 663} 664 665/* 666 * ext4_ext_split: 667 * inserts new subtree into the path, using free index entry 668 * at depth @at: 669 * - allocates all needed blocks (new leaf and all intermediate index blocks) 670 * - makes decision where to split 671 * - moves remaining extents and index entries (right to the split point) 672 * into the newly allocated blocks 673 * - initializes subtree 674 */ 675static int ext4_ext_split(handle_t *handle, struct inode *inode, 676 struct ext4_ext_path *path, 677 struct ext4_extent *newext, int at) 678{ 679 struct buffer_head *bh = NULL; 680 int depth = ext_depth(inode); 681 struct ext4_extent_header *neh; 682 struct ext4_extent_idx *fidx; 683 struct ext4_extent *ex; 684 int i = at, k, m, a; 685 ext4_fsblk_t newblock, oldblock; 686 __le32 border; 687 ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */ 688 int err = 0; 689 690 /* make decision: where to split? */ 691 /* FIXME: now decision is simplest: at current extent */ 692 693 /* if current leaf will be split, then we should use 694 * border from split point */ 695 BUG_ON(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr)); 696 if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) { 697 border = path[depth].p_ext[1].ee_block; 698 ext_debug("leaf will be split." 699 " next leaf starts at %d\n", 700 le32_to_cpu(border)); 701 } else { 702 border = newext->ee_block; 703 ext_debug("leaf will be added." 704 " next leaf starts at %d\n", 705 le32_to_cpu(border)); 706 } 707 708 /* 709 * If error occurs, then we break processing 710 * and mark filesystem read-only. index won't 711 * be inserted and tree will be in consistent 712 * state. Next mount will repair buffers too. 713 */ 714 715 /* 716 * Get array to track all allocated blocks. 717 * We need this to handle errors and free blocks 718 * upon them. 719 */ 720 ablocks = kzalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS); 721 if (!ablocks) 722 return -ENOMEM; 723 724 /* allocate all needed blocks */ 725 ext_debug("allocate %d blocks for indexes/leaf\n", depth - at); 726 for (a = 0; a < depth - at; a++) { 727 newblock = ext4_ext_new_meta_block(handle, inode, path, 728 newext, &err); 729 if (newblock == 0) 730 goto cleanup; 731 ablocks[a] = newblock; 732 } 733 734 /* initialize new leaf */ 735 newblock = ablocks[--a]; 736 BUG_ON(newblock == 0); 737 bh = sb_getblk(inode->i_sb, newblock); 738 if (!bh) { 739 err = -EIO; 740 goto cleanup; 741 } 742 lock_buffer(bh); 743 744 err = ext4_journal_get_create_access(handle, bh); 745 if (err) 746 goto cleanup; 747 748 neh = ext_block_hdr(bh); 749 neh->eh_entries = 0; 750 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode)); 751 neh->eh_magic = EXT4_EXT_MAGIC; 752 neh->eh_depth = 0; 753 ex = EXT_FIRST_EXTENT(neh); 754 755 /* move remainder of path[depth] to the new leaf */ 756 BUG_ON(path[depth].p_hdr->eh_entries != path[depth].p_hdr->eh_max); 757 /* start copy from next extent */ 758 /* TODO: we could do it by single memmove */ 759 m = 0; 760 path[depth].p_ext++; 761 while (path[depth].p_ext <= 762 EXT_MAX_EXTENT(path[depth].p_hdr)) { 763 ext_debug("move %d:%llu:%d in new leaf %llu\n", 764 le32_to_cpu(path[depth].p_ext->ee_block), 765 ext_pblock(path[depth].p_ext), 766 ext4_ext_get_actual_len(path[depth].p_ext), 767 newblock); 768 /*memmove(ex++, path[depth].p_ext++, 769 sizeof(struct ext4_extent)); 770 neh->eh_entries++;*/ 771 path[depth].p_ext++; 772 m++; 773 } 774 if (m) { 775 memmove(ex, path[depth].p_ext-m, sizeof(struct ext4_extent)*m); 776 le16_add_cpu(&neh->eh_entries, m); 777 } 778 779 set_buffer_uptodate(bh); 780 unlock_buffer(bh); 781 782 err = ext4_journal_dirty_metadata(handle, bh); 783 if (err) 784 goto cleanup; 785 brelse(bh); 786 bh = NULL; 787 788 /* correct old leaf */ 789 if (m) { 790 err = ext4_ext_get_access(handle, inode, path + depth); 791 if (err) 792 goto cleanup; 793 le16_add_cpu(&path[depth].p_hdr->eh_entries, -m); 794 err = ext4_ext_dirty(handle, inode, path + depth); 795 if (err) 796 goto cleanup; 797 798 } 799 800 /* create intermediate indexes */ 801 k = depth - at - 1; 802 BUG_ON(k < 0); 803 if (k) 804 ext_debug("create %d intermediate indices\n", k); 805 /* insert new index into current index block */ 806 /* current depth stored in i var */ 807 i = depth - 1; 808 while (k--) { 809 oldblock = newblock; 810 newblock = ablocks[--a]; 811 bh = sb_getblk(inode->i_sb, newblock); 812 if (!bh) { 813 err = -EIO; 814 goto cleanup; 815 } 816 lock_buffer(bh); 817 818 err = ext4_journal_get_create_access(handle, bh); 819 if (err) 820 goto cleanup; 821 822 neh = ext_block_hdr(bh); 823 neh->eh_entries = cpu_to_le16(1); 824 neh->eh_magic = EXT4_EXT_MAGIC; 825 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode)); 826 neh->eh_depth = cpu_to_le16(depth - i); 827 fidx = EXT_FIRST_INDEX(neh); 828 fidx->ei_block = border; 829 ext4_idx_store_pblock(fidx, oldblock); 830 831 ext_debug("int.index at %d (block %llu): %u -> %llu\n", 832 i, newblock, le32_to_cpu(border), oldblock); 833 /* copy indexes */ 834 m = 0; 835 path[i].p_idx++; 836 837 ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx, 838 EXT_MAX_INDEX(path[i].p_hdr)); 839 BUG_ON(EXT_MAX_INDEX(path[i].p_hdr) != 840 EXT_LAST_INDEX(path[i].p_hdr)); 841 while (path[i].p_idx <= EXT_MAX_INDEX(path[i].p_hdr)) { 842 ext_debug("%d: move %d:%llu in new index %llu\n", i, 843 le32_to_cpu(path[i].p_idx->ei_block), 844 idx_pblock(path[i].p_idx), 845 newblock); 846 /*memmove(++fidx, path[i].p_idx++, 847 sizeof(struct ext4_extent_idx)); 848 neh->eh_entries++; 849 BUG_ON(neh->eh_entries > neh->eh_max);*/ 850 path[i].p_idx++; 851 m++; 852 } 853 if (m) { 854 memmove(++fidx, path[i].p_idx - m, 855 sizeof(struct ext4_extent_idx) * m); 856 le16_add_cpu(&neh->eh_entries, m); 857 } 858 set_buffer_uptodate(bh); 859 unlock_buffer(bh); 860 861 err = ext4_journal_dirty_metadata(handle, bh); 862 if (err) 863 goto cleanup; 864 brelse(bh); 865 bh = NULL; 866 867 /* correct old index */ 868 if (m) { 869 err = ext4_ext_get_access(handle, inode, path + i); 870 if (err) 871 goto cleanup; 872 le16_add_cpu(&path[i].p_hdr->eh_entries, -m); 873 err = ext4_ext_dirty(handle, inode, path + i); 874 if (err) 875 goto cleanup; 876 } 877 878 i--; 879 } 880 881 /* insert new index */ 882 err = ext4_ext_insert_index(handle, inode, path + at, 883 le32_to_cpu(border), newblock); 884 885cleanup: 886 if (bh) { 887 if (buffer_locked(bh)) 888 unlock_buffer(bh); 889 brelse(bh); 890 } 891 892 if (err) { 893 /* free all allocated blocks in error case */ 894 for (i = 0; i < depth; i++) { 895 if (!ablocks[i]) 896 continue; 897 ext4_free_blocks(handle, inode, ablocks[i], 1, 1); 898 } 899 } 900 kfree(ablocks); 901 902 return err; 903} 904 905/* 906 * ext4_ext_grow_indepth: 907 * implements tree growing procedure: 908 * - allocates new block 909 * - moves top-level data (index block or leaf) into the new block 910 * - initializes new top-level, creating index that points to the 911 * just created block 912 */ 913static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode, 914 struct ext4_ext_path *path, 915 struct ext4_extent *newext) 916{ 917 struct ext4_ext_path *curp = path; 918 struct ext4_extent_header *neh; 919 struct ext4_extent_idx *fidx; 920 struct buffer_head *bh; 921 ext4_fsblk_t newblock; 922 int err = 0; 923 924 newblock = ext4_ext_new_meta_block(handle, inode, path, newext, &err); 925 if (newblock == 0) 926 return err; 927 928 bh = sb_getblk(inode->i_sb, newblock); 929 if (!bh) { 930 err = -EIO; 931 ext4_std_error(inode->i_sb, err); 932 return err; 933 } 934 lock_buffer(bh); 935 936 err = ext4_journal_get_create_access(handle, bh); 937 if (err) { 938 unlock_buffer(bh); 939 goto out; 940 } 941 942 /* move top-level index/leaf into new block */ 943 memmove(bh->b_data, curp->p_hdr, sizeof(EXT4_I(inode)->i_data)); 944 945 /* set size of new block */ 946 neh = ext_block_hdr(bh); 947 /* old root could have indexes or leaves 948 * so calculate e_max right way */ 949 if (ext_depth(inode)) 950 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode)); 951 else 952 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode)); 953 neh->eh_magic = EXT4_EXT_MAGIC; 954 set_buffer_uptodate(bh); 955 unlock_buffer(bh); 956 957 err = ext4_journal_dirty_metadata(handle, bh); 958 if (err) 959 goto out; 960 961 /* create index in new top-level index: num,max,pointer */ 962 err = ext4_ext_get_access(handle, inode, curp); 963 if (err) 964 goto out; 965 966 curp->p_hdr->eh_magic = EXT4_EXT_MAGIC; 967 curp->p_hdr->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode)); 968 curp->p_hdr->eh_entries = cpu_to_le16(1); 969 curp->p_idx = EXT_FIRST_INDEX(curp->p_hdr); 970 971 if (path[0].p_hdr->eh_depth) 972 curp->p_idx->ei_block = 973 EXT_FIRST_INDEX(path[0].p_hdr)->ei_block; 974 else 975 curp->p_idx->ei_block = 976 EXT_FIRST_EXTENT(path[0].p_hdr)->ee_block; 977 ext4_idx_store_pblock(curp->p_idx, newblock); 978 979 neh = ext_inode_hdr(inode); 980 fidx = EXT_FIRST_INDEX(neh); 981 ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n", 982 le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max), 983 le32_to_cpu(fidx->ei_block), idx_pblock(fidx)); 984 985 neh->eh_depth = cpu_to_le16(path->p_depth + 1); 986 err = ext4_ext_dirty(handle, inode, curp); 987out: 988 brelse(bh); 989 990 return err; 991} 992 993/* 994 * ext4_ext_create_new_leaf: 995 * finds empty index and adds new leaf. 996 * if no free index is found, then it requests in-depth growing. 997 */ 998static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode, 999 struct ext4_ext_path *path, 1000 struct ext4_extent *newext) 1001{ 1002 struct ext4_ext_path *curp; 1003 int depth, i, err = 0; 1004 1005repeat: 1006 i = depth = ext_depth(inode); 1007 1008 /* walk up to the tree and look for free index entry */ 1009 curp = path + depth; 1010 while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) { 1011 i--; 1012 curp--; 1013 } 1014 1015 /* we use already allocated block for index block, 1016 * so subsequent data blocks should be contiguous */ 1017 if (EXT_HAS_FREE_INDEX(curp)) { 1018 /* if we found index with free entry, then use that 1019 * entry: create all needed subtree and add new leaf */ 1020 err = ext4_ext_split(handle, inode, path, newext, i); 1021 if (err) 1022 goto out; 1023 1024 /* refill path */ 1025 ext4_ext_drop_refs(path); 1026 path = ext4_ext_find_extent(inode, 1027 (ext4_lblk_t)le32_to_cpu(newext->ee_block), 1028 path); 1029 if (IS_ERR(path)) 1030 err = PTR_ERR(path); 1031 } else { 1032 /* tree is full, time to grow in depth */ 1033 err = ext4_ext_grow_indepth(handle, inode, path, newext); 1034 if (err) 1035 goto out; 1036 1037 /* refill path */ 1038 ext4_ext_drop_refs(path); 1039 path = ext4_ext_find_extent(inode, 1040 (ext4_lblk_t)le32_to_cpu(newext->ee_block), 1041 path); 1042 if (IS_ERR(path)) { 1043 err = PTR_ERR(path); 1044 goto out; 1045 } 1046 1047 /* 1048 * only first (depth 0 -> 1) produces free space; 1049 * in all other cases we have to split the grown tree 1050 */ 1051 depth = ext_depth(inode); 1052 if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) { 1053 /* now we need to split */ 1054 goto repeat; 1055 } 1056 } 1057 1058out: 1059 return err; 1060} 1061 1062/* 1063 * search the closest allocated block to the left for *logical 1064 * and returns it at @logical + it's physical address at @phys 1065 * if *logical is the smallest allocated block, the function 1066 * returns 0 at @phys 1067 * return value contains 0 (success) or error code 1068 */ 1069int 1070ext4_ext_search_left(struct inode *inode, struct ext4_ext_path *path, 1071 ext4_lblk_t *logical, ext4_fsblk_t *phys) 1072{ 1073 struct ext4_extent_idx *ix; 1074 struct ext4_extent *ex; 1075 int depth, ee_len; 1076 1077 BUG_ON(path == NULL); 1078 depth = path->p_depth; 1079 *phys = 0; 1080 1081 if (depth == 0 && path->p_ext == NULL) 1082 return 0; 1083 1084 /* usually extent in the path covers blocks smaller 1085 * then *logical, but it can be that extent is the 1086 * first one in the file */ 1087 1088 ex = path[depth].p_ext; 1089 ee_len = ext4_ext_get_actual_len(ex); 1090 if (*logical < le32_to_cpu(ex->ee_block)) { 1091 BUG_ON(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex); 1092 while (--depth >= 0) { 1093 ix = path[depth].p_idx; 1094 BUG_ON(ix != EXT_FIRST_INDEX(path[depth].p_hdr)); 1095 } 1096 return 0; 1097 } 1098 1099 BUG_ON(*logical < (le32_to_cpu(ex->ee_block) + ee_len)); 1100 1101 *logical = le32_to_cpu(ex->ee_block) + ee_len - 1; 1102 *phys = ext_pblock(ex) + ee_len - 1; 1103 return 0; 1104} 1105 1106/* 1107 * search the closest allocated block to the right for *logical 1108 * and returns it at @logical + it's physical address at @phys 1109 * if *logical is the smallest allocated block, the function 1110 * returns 0 at @phys 1111 * return value contains 0 (success) or error code 1112 */ 1113int 1114ext4_ext_search_right(struct inode *inode, struct ext4_ext_path *path, 1115 ext4_lblk_t *logical, ext4_fsblk_t *phys) 1116{ 1117 struct buffer_head *bh = NULL; 1118 struct ext4_extent_header *eh; 1119 struct ext4_extent_idx *ix; 1120 struct ext4_extent *ex; 1121 ext4_fsblk_t block; 1122 int depth, ee_len; 1123 1124 BUG_ON(path == NULL); 1125 depth = path->p_depth; 1126 *phys = 0; 1127 1128 if (depth == 0 && path->p_ext == NULL) 1129 return 0; 1130 1131 /* usually extent in the path covers blocks smaller 1132 * then *logical, but it can be that extent is the 1133 * first one in the file */ 1134 1135 ex = path[depth].p_ext; 1136 ee_len = ext4_ext_get_actual_len(ex); 1137 if (*logical < le32_to_cpu(ex->ee_block)) { 1138 BUG_ON(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex); 1139 while (--depth >= 0) { 1140 ix = path[depth].p_idx; 1141 BUG_ON(ix != EXT_FIRST_INDEX(path[depth].p_hdr)); 1142 } 1143 *logical = le32_to_cpu(ex->ee_block); 1144 *phys = ext_pblock(ex); 1145 return 0; 1146 } 1147 1148 BUG_ON(*logical < (le32_to_cpu(ex->ee_block) + ee_len)); 1149 1150 if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) { 1151 /* next allocated block in this leaf */ 1152 ex++; 1153 *logical = le32_to_cpu(ex->ee_block); 1154 *phys = ext_pblock(ex); 1155 return 0; 1156 } 1157 1158 /* go up and search for index to the right */ 1159 while (--depth >= 0) { 1160 ix = path[depth].p_idx; 1161 if (ix != EXT_LAST_INDEX(path[depth].p_hdr)) 1162 break; 1163 } 1164 1165 if (depth < 0) { 1166 /* we've gone up to the root and 1167 * found no index to the right */ 1168 return 0; 1169 } 1170 1171 /* we've found index to the right, let's 1172 * follow it and find the closest allocated 1173 * block to the right */ 1174 ix++; 1175 block = idx_pblock(ix); 1176 while (++depth < path->p_depth) { 1177 bh = sb_bread(inode->i_sb, block); 1178 if (bh == NULL) 1179 return -EIO; 1180 eh = ext_block_hdr(bh); 1181 if (ext4_ext_check_header(inode, eh, depth)) { 1182 put_bh(bh); 1183 return -EIO; 1184 } 1185 ix = EXT_FIRST_INDEX(eh); 1186 block = idx_pblock(ix); 1187 put_bh(bh); 1188 } 1189 1190 bh = sb_bread(inode->i_sb, block); 1191 if (bh == NULL) 1192 return -EIO; 1193 eh = ext_block_hdr(bh); 1194 if (ext4_ext_check_header(inode, eh, path->p_depth - depth)) { 1195 put_bh(bh); 1196 return -EIO; 1197 } 1198 ex = EXT_FIRST_EXTENT(eh); 1199 *logical = le32_to_cpu(ex->ee_block); 1200 *phys = ext_pblock(ex); 1201 put_bh(bh); 1202 return 0; 1203 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_tree_changed(inode); 1625 ext4_ext_invalidate_cache(inode); 1626 return err; 1627} 1628 1629static void 1630ext4_ext_put_in_cache(struct inode *inode, ext4_lblk_t block, 1631 __u32 len, ext4_fsblk_t start, int type) 1632{ 1633 struct ext4_ext_cache *cex; 1634 BUG_ON(len == 0); 1635 cex = &EXT4_I(inode)->i_cached_extent; 1636 cex->ec_type = type; 1637 cex->ec_block = block; 1638 cex->ec_len = len; 1639 cex->ec_start = start; 1640} 1641 1642/* 1643 * ext4_ext_put_gap_in_cache: 1644 * calculate boundaries of the gap that the requested block fits into 1645 * and cache this gap 1646 */ 1647static void 1648ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path, 1649 ext4_lblk_t block) 1650{ 1651 int depth = ext_depth(inode); 1652 unsigned long len; 1653 ext4_lblk_t lblock; 1654 struct ext4_extent *ex; 1655 1656 ex = path[depth].p_ext; 1657 if (ex == NULL) { 1658 /* there is no extent yet, so gap is [0;-] */ 1659 lblock = 0; 1660 len = EXT_MAX_BLOCK; 1661 ext_debug("cache gap(whole file):"); 1662 } else if (block < le32_to_cpu(ex->ee_block)) { 1663 lblock = block; 1664 len = le32_to_cpu(ex->ee_block) - block; 1665 ext_debug("cache gap(before): %u [%u:%u]", 1666 block, 1667 le32_to_cpu(ex->ee_block), 1668 ext4_ext_get_actual_len(ex)); 1669 } else if (block >= le32_to_cpu(ex->ee_block) 1670 + ext4_ext_get_actual_len(ex)) { 1671 ext4_lblk_t next; 1672 lblock = le32_to_cpu(ex->ee_block) 1673 + ext4_ext_get_actual_len(ex); 1674 1675 next = ext4_ext_next_allocated_block(path); 1676 ext_debug("cache gap(after): [%u:%u] %u", 1677 le32_to_cpu(ex->ee_block), 1678 ext4_ext_get_actual_len(ex), 1679 block); 1680 BUG_ON(next == lblock); 1681 len = next - lblock; 1682 } else { 1683 lblock = len = 0; 1684 BUG(); 1685 } 1686 1687 ext_debug(" -> %u:%lu\n", lblock, len); 1688 ext4_ext_put_in_cache(inode, lblock, len, 0, EXT4_EXT_CACHE_GAP); 1689} 1690 1691static int 1692ext4_ext_in_cache(struct inode *inode, ext4_lblk_t block, 1693 struct ext4_extent *ex) 1694{ 1695 struct ext4_ext_cache *cex; 1696 1697 cex = &EXT4_I(inode)->i_cached_extent; 1698 1699 /* has cache valid data? */ 1700 if (cex->ec_type == EXT4_EXT_CACHE_NO) 1701 return EXT4_EXT_CACHE_NO; 1702 1703 BUG_ON(cex->ec_type != EXT4_EXT_CACHE_GAP && 1704 cex->ec_type != EXT4_EXT_CACHE_EXTENT); 1705 if (block >= cex->ec_block && block < cex->ec_block + cex->ec_len) { 1706 ex->ee_block = cpu_to_le32(cex->ec_block); 1707 ext4_ext_store_pblock(ex, cex->ec_start); 1708 ex->ee_len = cpu_to_le16(cex->ec_len); 1709 ext_debug("%u cached by %u:%u:%llu\n", 1710 block, 1711 cex->ec_block, cex->ec_len, cex->ec_start); 1712 return cex->ec_type; 1713 } 1714 1715 /* not in cache */ 1716 return EXT4_EXT_CACHE_NO; 1717} 1718 1719/* 1720 * ext4_ext_rm_idx: 1721 * removes index from the index block. 1722 * It's used in truncate case only, thus all requests are for 1723 * last index in the block only. 1724 */ 1725static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode, 1726 struct ext4_ext_path *path) 1727{ 1728 struct buffer_head *bh; 1729 int err; 1730 ext4_fsblk_t leaf; 1731 1732 /* free index block */ 1733 path--; 1734 leaf = idx_pblock(path->p_idx); 1735 BUG_ON(path->p_hdr->eh_entries == 0); 1736 err = ext4_ext_get_access(handle, inode, path); 1737 if (err) 1738 return err; 1739 le16_add_cpu(&path->p_hdr->eh_entries, -1); 1740 err = ext4_ext_dirty(handle, inode, path); 1741 if (err) 1742 return err; 1743 ext_debug("index is empty, remove it, free block %llu\n", leaf); 1744 bh = sb_find_get_block(inode->i_sb, leaf); 1745 ext4_forget(handle, 1, inode, bh, leaf); 1746 ext4_free_blocks(handle, inode, leaf, 1, 1); 1747 return err; 1748} 1749 1750/* 1751 * ext4_ext_calc_credits_for_single_extent: 1752 * This routine returns max. credits that needed to insert an extent 1753 * to the extent tree. 1754 * When pass the actual path, the caller should calculate credits 1755 * under i_data_sem. 1756 */ 1757int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks, 1758 struct ext4_ext_path *path) 1759{ 1760 if (path) { 1761 int depth = ext_depth(inode); 1762 int ret = 0; 1763 1764 /* probably there is space in leaf? */ 1765 if (le16_to_cpu(path[depth].p_hdr->eh_entries) 1766 < le16_to_cpu(path[depth].p_hdr->eh_max)) { 1767 1768 /* 1769 * There are some space in the leaf tree, no 1770 * need to account for leaf block credit 1771 * 1772 * bitmaps and block group descriptor blocks 1773 * and other metadat blocks still need to be 1774 * accounted. 1775 */ 1776 /* 1 bitmap, 1 block group descriptor */ 1777 ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb); 1778 } 1779 } 1780 1781 return ext4_chunk_trans_blocks(inode, nrblocks); 1782} 1783 1784/* 1785 * How many index/leaf blocks need to change/allocate to modify nrblocks? 1786 * 1787 * if nrblocks are fit in a single extent (chunk flag is 1), then 1788 * in the worse case, each tree level index/leaf need to be changed 1789 * if the tree split due to insert a new extent, then the old tree 1790 * index/leaf need to be updated too 1791 * 1792 * If the nrblocks are discontiguous, they could cause 1793 * the whole tree split more than once, but this is really rare. 1794 */ 1795int ext4_ext_index_trans_blocks(struct inode *inode, int nrblocks, int chunk) 1796{ 1797 int index; 1798 int depth = ext_depth(inode); 1799 1800 if (chunk) 1801 index = depth * 2; 1802 else 1803 index = depth * 3; 1804 1805 return index; 1806} 1807 1808static int ext4_remove_blocks(handle_t *handle, struct inode *inode, 1809 struct ext4_extent *ex, 1810 ext4_lblk_t from, ext4_lblk_t to) 1811{ 1812 struct buffer_head *bh; 1813 unsigned short ee_len = ext4_ext_get_actual_len(ex); 1814 int i, metadata = 0; 1815 1816 if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) 1817 metadata = 1; 1818#ifdef EXTENTS_STATS 1819 { 1820 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 1821 spin_lock(&sbi->s_ext_stats_lock); 1822 sbi->s_ext_blocks += ee_len; 1823 sbi->s_ext_extents++; 1824 if (ee_len < sbi->s_ext_min) 1825 sbi->s_ext_min = ee_len; 1826 if (ee_len > sbi->s_ext_max) 1827 sbi->s_ext_max = ee_len; 1828 if (ext_depth(inode) > sbi->s_depth_max) 1829 sbi->s_depth_max = ext_depth(inode); 1830 spin_unlock(&sbi->s_ext_stats_lock); 1831 } 1832#endif 1833 if (from >= le32_to_cpu(ex->ee_block) 1834 && to == le32_to_cpu(ex->ee_block) + ee_len - 1) { 1835 /* tail removal */ 1836 ext4_lblk_t num; 1837 ext4_fsblk_t start; 1838 1839 num = le32_to_cpu(ex->ee_block) + ee_len - from; 1840 start = ext_pblock(ex) + ee_len - num; 1841 ext_debug("free last %u blocks starting %llu\n", num, start); 1842 for (i = 0; i < num; i++) { 1843 bh = sb_find_get_block(inode->i_sb, start + i); 1844 ext4_forget(handle, 0, inode, bh, start + i); 1845 } 1846 ext4_free_blocks(handle, inode, start, num, metadata); 1847 } else if (from == le32_to_cpu(ex->ee_block) 1848 && to <= le32_to_cpu(ex->ee_block) + ee_len - 1) { 1849 printk(KERN_INFO "strange request: removal %u-%u from %u:%u\n", 1850 from, to, le32_to_cpu(ex->ee_block), ee_len); 1851 } else { 1852 printk(KERN_INFO "strange request: removal(2) " 1853 "%u-%u from %u:%u\n", 1854 from, to, le32_to_cpu(ex->ee_block), ee_len); 1855 } 1856 return 0; 1857} 1858 1859static int 1860ext4_ext_rm_leaf(handle_t *handle, struct inode *inode, 1861 struct ext4_ext_path *path, ext4_lblk_t start) 1862{ 1863 int err = 0, correct_index = 0; 1864 int depth = ext_depth(inode), credits; 1865 struct ext4_extent_header *eh; 1866 ext4_lblk_t a, b, block; 1867 unsigned num; 1868 ext4_lblk_t ex_ee_block; 1869 unsigned short ex_ee_len; 1870 unsigned uninitialized = 0; 1871 struct ext4_extent *ex; 1872 1873 /* the header must be checked already in ext4_ext_remove_space() */ 1874 ext_debug("truncate since %u in leaf\n", start); 1875 if (!path[depth].p_hdr) 1876 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh); 1877 eh = path[depth].p_hdr; 1878 BUG_ON(eh == NULL); 1879 1880 /* find where to start removing */ 1881 ex = EXT_LAST_EXTENT(eh); 1882 1883 ex_ee_block = le32_to_cpu(ex->ee_block); 1884 if (ext4_ext_is_uninitialized(ex)) 1885 uninitialized = 1; 1886 ex_ee_len = ext4_ext_get_actual_len(ex); 1887 1888 while (ex >= EXT_FIRST_EXTENT(eh) && 1889 ex_ee_block + ex_ee_len > start) { 1890 ext_debug("remove ext %lu:%u\n", ex_ee_block, ex_ee_len); 1891 path[depth].p_ext = ex; 1892 1893 a = ex_ee_block > start ? ex_ee_block : start; 1894 b = ex_ee_block + ex_ee_len - 1 < EXT_MAX_BLOCK ? 1895 ex_ee_block + ex_ee_len - 1 : EXT_MAX_BLOCK; 1896 1897 ext_debug(" border %u:%u\n", a, b); 1898 1899 if (a != ex_ee_block && b != ex_ee_block + ex_ee_len - 1) { 1900 block = 0; 1901 num = 0; 1902 BUG(); 1903 } else if (a != ex_ee_block) { 1904 /* remove tail of the extent */ 1905 block = ex_ee_block; 1906 num = a - block; 1907 } else if (b != ex_ee_block + ex_ee_len - 1) { 1908 /* remove head of the extent */ 1909 block = a; 1910 num = b - a; 1911 /* there is no "make a hole" API yet */ 1912 BUG(); 1913 } else { 1914 /* remove whole extent: excellent! */ 1915 block = ex_ee_block; 1916 num = 0; 1917 BUG_ON(a != ex_ee_block); 1918 BUG_ON(b != ex_ee_block + ex_ee_len - 1); 1919 } 1920 1921 /* 1922 * 3 for leaf, sb, and inode plus 2 (bmap and group 1923 * descriptor) for each block group; assume two block 1924 * groups plus ex_ee_len/blocks_per_block_group for 1925 * the worst case 1926 */ 1927 credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb)); 1928 if (ex == EXT_FIRST_EXTENT(eh)) { 1929 correct_index = 1; 1930 credits += (ext_depth(inode)) + 1; 1931 } 1932 credits += 2 * EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb); 1933 1934 err = ext4_ext_journal_restart(handle, credits); 1935 if (err) 1936 goto out; 1937 1938 err = ext4_ext_get_access(handle, inode, path + depth); 1939 if (err) 1940 goto out; 1941 1942 err = ext4_remove_blocks(handle, inode, ex, a, b); 1943 if (err) 1944 goto out; 1945 1946 if (num == 0) { 1947 /* this extent is removed; mark slot entirely unused */ 1948 ext4_ext_store_pblock(ex, 0); 1949 le16_add_cpu(&eh->eh_entries, -1); 1950 } 1951 1952 ex->ee_block = cpu_to_le32(block); 1953 ex->ee_len = cpu_to_le16(num); 1954 /* 1955 * Do not mark uninitialized if all the blocks in the 1956 * extent have been removed. 1957 */ 1958 if (uninitialized && num) 1959 ext4_ext_mark_uninitialized(ex); 1960 1961 err = ext4_ext_dirty(handle, inode, path + depth); 1962 if (err) 1963 goto out; 1964 1965 ext_debug("new extent: %u:%u:%llu\n", block, num, 1966 ext_pblock(ex)); 1967 ex--; 1968 ex_ee_block = le32_to_cpu(ex->ee_block); 1969 ex_ee_len = ext4_ext_get_actual_len(ex); 1970 } 1971 1972 if (correct_index && eh->eh_entries) 1973 err = ext4_ext_correct_indexes(handle, inode, path); 1974 1975 /* if this leaf is free, then we should 1976 * remove it from index block above */ 1977 if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL) 1978 err = ext4_ext_rm_idx(handle, inode, path + depth); 1979 1980out: 1981 return err; 1982} 1983 1984/* 1985 * ext4_ext_more_to_rm: 1986 * returns 1 if current index has to be freed (even partial) 1987 */ 1988static int 1989ext4_ext_more_to_rm(struct ext4_ext_path *path) 1990{ 1991 BUG_ON(path->p_idx == NULL); 1992 1993 if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr)) 1994 return 0; 1995 1996 /* 1997 * if truncate on deeper level happened, it wasn't partial, 1998 * so we have to consider current index for truncation 1999 */ 2000 if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block) 2001 return 0; 2002 return 1; 2003} 2004 2005static int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start) 2006{ 2007 struct super_block *sb = inode->i_sb; 2008 int depth = ext_depth(inode); 2009 struct ext4_ext_path *path; 2010 handle_t *handle; 2011 int i = 0, err = 0; 2012 2013 ext_debug("truncate since %u\n", start); 2014 2015 /* probably first extent we're gonna free will be last in block */ 2016 handle = ext4_journal_start(inode, depth + 1); 2017 if (IS_ERR(handle)) 2018 return PTR_ERR(handle); 2019 2020 ext4_ext_invalidate_cache(inode); 2021 2022 /* 2023 * We start scanning from right side, freeing all the blocks 2024 * after i_size and walking into the tree depth-wise. 2025 */ 2026 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1), GFP_NOFS); 2027 if (path == NULL) { 2028 ext4_journal_stop(handle); 2029 return -ENOMEM; 2030 } 2031 path[0].p_hdr = ext_inode_hdr(inode); 2032 if (ext4_ext_check_header(inode, path[0].p_hdr, depth)) { 2033 err = -EIO; 2034 goto out; 2035 } 2036 path[0].p_depth = depth; 2037 2038 while (i >= 0 && err == 0) { 2039 if (i == depth) { 2040 /* this is leaf block */ 2041 err = ext4_ext_rm_leaf(handle, inode, path, start); 2042 /* root level has p_bh == NULL, brelse() eats this */ 2043 brelse(path[i].p_bh); 2044 path[i].p_bh = NULL; 2045 i--; 2046 continue; 2047 } 2048 2049 /* this is index block */ 2050 if (!path[i].p_hdr) { 2051 ext_debug("initialize header\n"); 2052 path[i].p_hdr = ext_block_hdr(path[i].p_bh); 2053 } 2054 2055 if (!path[i].p_idx) { 2056 /* this level hasn't been touched yet */ 2057 path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr); 2058 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1; 2059 ext_debug("init index ptr: hdr 0x%p, num %d\n", 2060 path[i].p_hdr, 2061 le16_to_cpu(path[i].p_hdr->eh_entries)); 2062 } else { 2063 /* we were already here, see at next index */ 2064 path[i].p_idx--; 2065 } 2066 2067 ext_debug("level %d - index, first 0x%p, cur 0x%p\n", 2068 i, EXT_FIRST_INDEX(path[i].p_hdr), 2069 path[i].p_idx); 2070 if (ext4_ext_more_to_rm(path + i)) { 2071 struct buffer_head *bh; 2072 /* go to the next level */ 2073 ext_debug("move to level %d (block %llu)\n", 2074 i + 1, idx_pblock(path[i].p_idx)); 2075 memset(path + i + 1, 0, sizeof(*path)); 2076 bh = sb_bread(sb, idx_pblock(path[i].p_idx)); 2077 if (!bh) { 2078 /* should we reset i_size? */ 2079 err = -EIO; 2080 break; 2081 } 2082 if (WARN_ON(i + 1 > depth)) { 2083 err = -EIO; 2084 break; 2085 } 2086 if (ext4_ext_check_header(inode, ext_block_hdr(bh), 2087 depth - i - 1)) { 2088 err = -EIO; 2089 break; 2090 } 2091 path[i + 1].p_bh = bh; 2092 2093 /* save actual number of indexes since this 2094 * number is changed at the next iteration */ 2095 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries); 2096 i++; 2097 } else { 2098 /* we finished processing this index, go up */ 2099 if (path[i].p_hdr->eh_entries == 0 && i > 0) { 2100 /* index is empty, remove it; 2101 * handle must be already prepared by the 2102 * truncatei_leaf() */ 2103 err = ext4_ext_rm_idx(handle, inode, path + i); 2104 } 2105 /* root level has p_bh == NULL, brelse() eats this */ 2106 brelse(path[i].p_bh); 2107 path[i].p_bh = NULL; 2108 i--; 2109 ext_debug("return to level %d\n", i); 2110 } 2111 } 2112 2113 /* TODO: flexible tree reduction should be here */ 2114 if (path->p_hdr->eh_entries == 0) { 2115 /* 2116 * truncate to zero freed all the tree, 2117 * so we need to correct eh_depth 2118 */ 2119 err = ext4_ext_get_access(handle, inode, path); 2120 if (err == 0) { 2121 ext_inode_hdr(inode)->eh_depth = 0; 2122 ext_inode_hdr(inode)->eh_max = 2123 cpu_to_le16(ext4_ext_space_root(inode)); 2124 err = ext4_ext_dirty(handle, inode, path); 2125 } 2126 } 2127out: 2128 ext4_ext_tree_changed(inode); 2129 ext4_ext_drop_refs(path); 2130 kfree(path); 2131 ext4_journal_stop(handle); 2132 2133 return err; 2134} 2135 2136/* 2137 * called at mount time 2138 */ 2139void ext4_ext_init(struct super_block *sb) 2140{ 2141 /* 2142 * possible initialization would be here 2143 */ 2144 2145 if (test_opt(sb, EXTENTS)) { 2146 printk(KERN_INFO "EXT4-fs: file extents enabled"); 2147#ifdef AGGRESSIVE_TEST 2148 printk(", aggressive tests"); 2149#endif 2150#ifdef CHECK_BINSEARCH 2151 printk(", check binsearch"); 2152#endif 2153#ifdef EXTENTS_STATS 2154 printk(", stats"); 2155#endif 2156 printk("\n"); 2157#ifdef EXTENTS_STATS 2158 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock); 2159 EXT4_SB(sb)->s_ext_min = 1 << 30; 2160 EXT4_SB(sb)->s_ext_max = 0; 2161#endif 2162 } 2163} 2164 2165/* 2166 * called at umount time 2167 */ 2168void ext4_ext_release(struct super_block *sb) 2169{ 2170 if (!test_opt(sb, EXTENTS)) 2171 return; 2172 2173#ifdef EXTENTS_STATS 2174 if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) { 2175 struct ext4_sb_info *sbi = EXT4_SB(sb); 2176 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n", 2177 sbi->s_ext_blocks, sbi->s_ext_extents, 2178 sbi->s_ext_blocks / sbi->s_ext_extents); 2179 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n", 2180 sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max); 2181 } 2182#endif 2183} 2184 2185static void bi_complete(struct bio *bio, int error) 2186{ 2187 complete((struct completion *)bio->bi_private); 2188} 2189 2190/* FIXME!! we need to try to merge to left or right after zero-out */ 2191static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex) 2192{ 2193 int ret = -EIO; 2194 struct bio *bio; 2195 int blkbits, blocksize; 2196 sector_t ee_pblock; 2197 struct completion event; 2198 unsigned int ee_len, len, done, offset; 2199 2200 2201 blkbits = inode->i_blkbits; 2202 blocksize = inode->i_sb->s_blocksize; 2203 ee_len = ext4_ext_get_actual_len(ex); 2204 ee_pblock = ext_pblock(ex); 2205 2206 /* convert ee_pblock to 512 byte sectors */ 2207 ee_pblock = ee_pblock << (blkbits - 9); 2208 2209 while (ee_len > 0) { 2210 2211 if (ee_len > BIO_MAX_PAGES) 2212 len = BIO_MAX_PAGES; 2213 else 2214 len = ee_len; 2215 2216 bio = bio_alloc(GFP_NOIO, len); 2217 if (!bio) 2218 return -ENOMEM; 2219 bio->bi_sector = ee_pblock; 2220 bio->bi_bdev = inode->i_sb->s_bdev; 2221 2222 done = 0; 2223 offset = 0; 2224 while (done < len) { 2225 ret = bio_add_page(bio, ZERO_PAGE(0), 2226 blocksize, offset); 2227 if (ret != blocksize) { 2228 /* 2229 * We can't add any more pages because of 2230 * hardware limitations. Start a new bio. 2231 */ 2232 break; 2233 } 2234 done++; 2235 offset += blocksize; 2236 if (offset >= PAGE_CACHE_SIZE) 2237 offset = 0; 2238 } 2239 2240 init_completion(&event); 2241 bio->bi_private = &event; 2242 bio->bi_end_io = bi_complete; 2243 submit_bio(WRITE, bio); 2244 wait_for_completion(&event); 2245 2246 if (test_bit(BIO_UPTODATE, &bio->bi_flags)) 2247 ret = 0; 2248 else { 2249 ret = -EIO; 2250 break; 2251 } 2252 bio_put(bio); 2253 ee_len -= done; 2254 ee_pblock += done << (blkbits - 9); 2255 } 2256 return ret; 2257} 2258 2259#define EXT4_EXT_ZERO_LEN 7 2260 2261/* 2262 * This function is called by ext4_ext_get_blocks() if someone tries to write 2263 * to an uninitialized extent. It may result in splitting the uninitialized 2264 * extent into multiple extents (upto three - one initialized and two 2265 * uninitialized). 2266 * There are three possibilities: 2267 * a> There is no split required: Entire extent should be initialized 2268 * b> Splits in two extents: Write is happening at either end of the extent 2269 * c> Splits in three extents: Somone is writing in middle of the extent 2270 */ 2271static int ext4_ext_convert_to_initialized(handle_t *handle, 2272 struct inode *inode, 2273 struct ext4_ext_path *path, 2274 ext4_lblk_t iblock, 2275 unsigned long max_blocks) 2276{ 2277 struct ext4_extent *ex, newex, orig_ex; 2278 struct ext4_extent *ex1 = NULL; 2279 struct ext4_extent *ex2 = NULL; 2280 struct ext4_extent *ex3 = NULL; 2281 struct ext4_extent_header *eh; 2282 ext4_lblk_t ee_block; 2283 unsigned int allocated, ee_len, depth; 2284 ext4_fsblk_t newblock; 2285 int err = 0; 2286 int ret = 0; 2287 2288 depth = ext_depth(inode); 2289 eh = path[depth].p_hdr; 2290 ex = path[depth].p_ext; 2291 ee_block = le32_to_cpu(ex->ee_block); 2292 ee_len = ext4_ext_get_actual_len(ex); 2293 allocated = ee_len - (iblock - ee_block); 2294 newblock = iblock - ee_block + ext_pblock(ex); 2295 ex2 = ex; 2296 orig_ex.ee_block = ex->ee_block; 2297 orig_ex.ee_len = cpu_to_le16(ee_len); 2298 ext4_ext_store_pblock(&orig_ex, ext_pblock(ex)); 2299 2300 err = ext4_ext_get_access(handle, inode, path + depth); 2301 if (err) 2302 goto out; 2303 /* If extent has less than 2*EXT4_EXT_ZERO_LEN zerout directly */ 2304 if (ee_len <= 2*EXT4_EXT_ZERO_LEN) { 2305 err = ext4_ext_zeroout(inode, &orig_ex); 2306 if (err) 2307 goto fix_extent_len; 2308 /* update the extent length and mark as initialized */ 2309 ex->ee_block = orig_ex.ee_block; 2310 ex->ee_len = orig_ex.ee_len; 2311 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2312 ext4_ext_dirty(handle, inode, path + depth); 2313 /* zeroed the full extent */ 2314 return allocated; 2315 } 2316 2317 /* ex1: ee_block to iblock - 1 : uninitialized */ 2318 if (iblock > ee_block) { 2319 ex1 = ex; 2320 ex1->ee_len = cpu_to_le16(iblock - ee_block); 2321 ext4_ext_mark_uninitialized(ex1); 2322 ex2 = &newex; 2323 } 2324 /* 2325 * for sanity, update the length of the ex2 extent before 2326 * we insert ex3, if ex1 is NULL. This is to avoid temporary 2327 * overlap of blocks. 2328 */ 2329 if (!ex1 && allocated > max_blocks) 2330 ex2->ee_len = cpu_to_le16(max_blocks); 2331 /* ex3: to ee_block + ee_len : uninitialised */ 2332 if (allocated > max_blocks) { 2333 unsigned int newdepth; 2334 /* If extent has less than EXT4_EXT_ZERO_LEN zerout directly */ 2335 if (allocated <= EXT4_EXT_ZERO_LEN) { 2336 /* 2337 * iblock == ee_block is handled by the zerouout 2338 * at the beginning. 2339 * Mark first half uninitialized. 2340 * Mark second half initialized and zero out the 2341 * initialized extent 2342 */ 2343 ex->ee_block = orig_ex.ee_block; 2344 ex->ee_len = cpu_to_le16(ee_len - allocated); 2345 ext4_ext_mark_uninitialized(ex); 2346 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2347 ext4_ext_dirty(handle, inode, path + depth); 2348 2349 ex3 = &newex; 2350 ex3->ee_block = cpu_to_le32(iblock); 2351 ext4_ext_store_pblock(ex3, newblock); 2352 ex3->ee_len = cpu_to_le16(allocated); 2353 err = ext4_ext_insert_extent(handle, inode, path, ex3); 2354 if (err == -ENOSPC) { 2355 err = ext4_ext_zeroout(inode, &orig_ex); 2356 if (err) 2357 goto fix_extent_len; 2358 ex->ee_block = orig_ex.ee_block; 2359 ex->ee_len = orig_ex.ee_len; 2360 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2361 ext4_ext_dirty(handle, inode, path + depth); 2362 /* blocks available from iblock */ 2363 return allocated; 2364 2365 } else if (err) 2366 goto fix_extent_len; 2367 2368 /* 2369 * We need to zero out the second half because 2370 * an fallocate request can update file size and 2371 * converting the second half to initialized extent 2372 * implies that we can leak some junk data to user 2373 * space. 2374 */ 2375 err = ext4_ext_zeroout(inode, ex3); 2376 if (err) { 2377 /* 2378 * We should actually mark the 2379 * second half as uninit and return error 2380 * Insert would have changed the extent 2381 */ 2382 depth = ext_depth(inode); 2383 ext4_ext_drop_refs(path); 2384 path = ext4_ext_find_extent(inode, 2385 iblock, path); 2386 if (IS_ERR(path)) { 2387 err = PTR_ERR(path); 2388 return err; 2389 } 2390 /* get the second half extent details */ 2391 ex = path[depth].p_ext; 2392 err = ext4_ext_get_access(handle, inode, 2393 path + depth); 2394 if (err) 2395 return err; 2396 ext4_ext_mark_uninitialized(ex); 2397 ext4_ext_dirty(handle, inode, path + depth); 2398 return err; 2399 } 2400 2401 /* zeroed the second half */ 2402 return allocated; 2403 } 2404 ex3 = &newex; 2405 ex3->ee_block = cpu_to_le32(iblock + max_blocks); 2406 ext4_ext_store_pblock(ex3, newblock + max_blocks); 2407 ex3->ee_len = cpu_to_le16(allocated - max_blocks); 2408 ext4_ext_mark_uninitialized(ex3); 2409 err = ext4_ext_insert_extent(handle, inode, path, ex3); 2410 if (err == -ENOSPC) { 2411 err = ext4_ext_zeroout(inode, &orig_ex); 2412 if (err) 2413 goto fix_extent_len; 2414 /* update the extent length and mark as initialized */ 2415 ex->ee_block = orig_ex.ee_block; 2416 ex->ee_len = orig_ex.ee_len; 2417 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2418 ext4_ext_dirty(handle, inode, path + depth); 2419 /* zeroed the full extent */ 2420 /* blocks available from iblock */ 2421 return allocated; 2422 2423 } else if (err) 2424 goto fix_extent_len; 2425 /* 2426 * The depth, and hence eh & ex might change 2427 * as part of the insert above. 2428 */ 2429 newdepth = ext_depth(inode); 2430 /* 2431 * update the extent length after successfull insert of the 2432 * split extent 2433 */ 2434 orig_ex.ee_len = cpu_to_le16(ee_len - 2435 ext4_ext_get_actual_len(ex3)); 2436 depth = newdepth; 2437 ext4_ext_drop_refs(path); 2438 path = ext4_ext_find_extent(inode, iblock, path); 2439 if (IS_ERR(path)) { 2440 err = PTR_ERR(path); 2441 goto out; 2442 } 2443 eh = path[depth].p_hdr; 2444 ex = path[depth].p_ext; 2445 if (ex2 != &newex) 2446 ex2 = ex; 2447 2448 err = ext4_ext_get_access(handle, inode, path + depth); 2449 if (err) 2450 goto out; 2451 2452 allocated = max_blocks; 2453 2454 /* If extent has less than EXT4_EXT_ZERO_LEN and we are trying 2455 * to insert a extent in the middle zerout directly 2456 * otherwise give the extent a chance to merge to left 2457 */ 2458 if (le16_to_cpu(orig_ex.ee_len) <= EXT4_EXT_ZERO_LEN && 2459 iblock != ee_block) { 2460 err = ext4_ext_zeroout(inode, &orig_ex); 2461 if (err) 2462 goto fix_extent_len; 2463 /* update the extent length and mark as initialized */ 2464 ex->ee_block = orig_ex.ee_block; 2465 ex->ee_len = orig_ex.ee_len; 2466 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2467 ext4_ext_dirty(handle, inode, path + depth); 2468 /* zero out the first half */ 2469 /* blocks available from iblock */ 2470 return allocated; 2471 } 2472 } 2473 /* 2474 * If there was a change of depth as part of the 2475 * insertion of ex3 above, we need to update the length 2476 * of the ex1 extent again here 2477 */ 2478 if (ex1 && ex1 != ex) { 2479 ex1 = ex; 2480 ex1->ee_len = cpu_to_le16(iblock - ee_block); 2481 ext4_ext_mark_uninitialized(ex1); 2482 ex2 = &newex; 2483 } 2484 /* ex2: iblock to iblock + maxblocks-1 : initialised */ 2485 ex2->ee_block = cpu_to_le32(iblock); 2486 ext4_ext_store_pblock(ex2, newblock); 2487 ex2->ee_len = cpu_to_le16(allocated); 2488 if (ex2 != ex) 2489 goto insert; 2490 /* 2491 * New (initialized) extent starts from the first block 2492 * in the current extent. i.e., ex2 == ex 2493 * We have to see if it can be merged with the extent 2494 * on the left. 2495 */ 2496 if (ex2 > EXT_FIRST_EXTENT(eh)) { 2497 /* 2498 * To merge left, pass "ex2 - 1" to try_to_merge(), 2499 * since it merges towards right _only_. 2500 */ 2501 ret = ext4_ext_try_to_merge(inode, path, ex2 - 1); 2502 if (ret) { 2503 err = ext4_ext_correct_indexes(handle, inode, path); 2504 if (err) 2505 goto out; 2506 depth = ext_depth(inode); 2507 ex2--; 2508 } 2509 } 2510 /* 2511 * Try to Merge towards right. This might be required 2512 * only when the whole extent is being written to. 2513 * i.e. ex2 == ex and ex3 == NULL. 2514 */ 2515 if (!ex3) { 2516 ret = ext4_ext_try_to_merge(inode, path, ex2); 2517 if (ret) { 2518 err = ext4_ext_correct_indexes(handle, inode, path); 2519 if (err) 2520 goto out; 2521 } 2522 } 2523 /* Mark modified extent as dirty */ 2524 err = ext4_ext_dirty(handle, inode, path + depth); 2525 goto out; 2526insert: 2527 err = ext4_ext_insert_extent(handle, inode, path, &newex); 2528 if (err == -ENOSPC) { 2529 err = ext4_ext_zeroout(inode, &orig_ex); 2530 if (err) 2531 goto fix_extent_len; 2532 /* update the extent length and mark as initialized */ 2533 ex->ee_block = orig_ex.ee_block; 2534 ex->ee_len = orig_ex.ee_len; 2535 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2536 ext4_ext_dirty(handle, inode, path + depth); 2537 /* zero out the first half */ 2538 return allocated; 2539 } else if (err) 2540 goto fix_extent_len; 2541out: 2542 return err ? err : allocated; 2543 2544fix_extent_len: 2545 ex->ee_block = orig_ex.ee_block; 2546 ex->ee_len = orig_ex.ee_len; 2547 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2548 ext4_ext_mark_uninitialized(ex); 2549 ext4_ext_dirty(handle, inode, path + depth); 2550 return err; 2551} 2552 2553/* 2554 * Block allocation/map/preallocation routine for extents based files 2555 * 2556 * 2557 * Need to be called with 2558 * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block 2559 * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem) 2560 * 2561 * return > 0, number of of blocks already mapped/allocated 2562 * if create == 0 and these are pre-allocated blocks 2563 * buffer head is unmapped 2564 * otherwise blocks are mapped 2565 * 2566 * return = 0, if plain look up failed (blocks have not been allocated) 2567 * buffer head is unmapped 2568 * 2569 * return < 0, error case. 2570 */ 2571int ext4_ext_get_blocks(handle_t *handle, struct inode *inode, 2572 ext4_lblk_t iblock, 2573 unsigned long max_blocks, struct buffer_head *bh_result, 2574 int create, int extend_disksize) 2575{ 2576 struct ext4_ext_path *path = NULL; 2577 struct ext4_extent_header *eh; 2578 struct ext4_extent newex, *ex; 2579 ext4_fsblk_t goal, newblock; 2580 int err = 0, depth, ret; 2581 unsigned long allocated = 0; 2582 struct ext4_allocation_request ar; 2583 loff_t disksize; 2584 2585 __clear_bit(BH_New, &bh_result->b_state); 2586 ext_debug("blocks %u/%lu requested for inode %u\n", 2587 iblock, max_blocks, inode->i_ino); 2588 2589 /* check in cache */ 2590 goal = ext4_ext_in_cache(inode, iblock, &newex); 2591 if (goal) { 2592 if (goal == EXT4_EXT_CACHE_GAP) { 2593 if (!create) { 2594 /* 2595 * block isn't allocated yet and 2596 * user doesn't want to allocate it 2597 */ 2598 goto out2; 2599 } 2600 /* we should allocate requested block */ 2601 } else if (goal == EXT4_EXT_CACHE_EXTENT) { 2602 /* block is already allocated */ 2603 newblock = iblock 2604 - le32_to_cpu(newex.ee_block) 2605 + ext_pblock(&newex); 2606 /* number of remaining blocks in the extent */ 2607 allocated = ext4_ext_get_actual_len(&newex) - 2608 (iblock - le32_to_cpu(newex.ee_block)); 2609 goto out; 2610 } else { 2611 BUG(); 2612 } 2613 } 2614 2615 /* find extent for this block */ 2616 path = ext4_ext_find_extent(inode, iblock, NULL); 2617 if (IS_ERR(path)) { 2618 err = PTR_ERR(path); 2619 path = NULL; 2620 goto out2; 2621 } 2622 2623 depth = ext_depth(inode); 2624 2625 /* 2626 * consistent leaf must not be empty; 2627 * this situation is possible, though, _during_ tree modification; 2628 * this is why assert can't be put in ext4_ext_find_extent() 2629 */ 2630 BUG_ON(path[depth].p_ext == NULL && depth != 0); 2631 eh = path[depth].p_hdr; 2632 2633 ex = path[depth].p_ext; 2634 if (ex) { 2635 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block); 2636 ext4_fsblk_t ee_start = ext_pblock(ex); 2637 unsigned short ee_len; 2638 2639 /* 2640 * Uninitialized extents are treated as holes, except that 2641 * we split out initialized portions during a write. 2642 */ 2643 ee_len = ext4_ext_get_actual_len(ex); 2644 /* if found extent covers block, simply return it */ 2645 if (iblock >= ee_block && iblock < ee_block + ee_len) { 2646 newblock = iblock - ee_block + ee_start; 2647 /* number of remaining blocks in the extent */ 2648 allocated = ee_len - (iblock - ee_block); 2649 ext_debug("%u fit into %lu:%d -> %llu\n", iblock, 2650 ee_block, ee_len, newblock); 2651 2652 /* Do not put uninitialized extent in the cache */ 2653 if (!ext4_ext_is_uninitialized(ex)) { 2654 ext4_ext_put_in_cache(inode, ee_block, 2655 ee_len, ee_start, 2656 EXT4_EXT_CACHE_EXTENT); 2657 goto out; 2658 } 2659 if (create == EXT4_CREATE_UNINITIALIZED_EXT) 2660 goto out; 2661 if (!create) { 2662 /* 2663 * We have blocks reserved already. We 2664 * return allocated blocks so that delalloc 2665 * won't do block reservation for us. But 2666 * the buffer head will be unmapped so that 2667 * a read from the block returns 0s. 2668 */ 2669 if (allocated > max_blocks) 2670 allocated = max_blocks; 2671 set_buffer_unwritten(bh_result); 2672 goto out2; 2673 } 2674 2675 ret = ext4_ext_convert_to_initialized(handle, inode, 2676 path, iblock, 2677 max_blocks); 2678 if (ret <= 0) { 2679 err = ret; 2680 goto out2; 2681 } else 2682 allocated = ret; 2683 goto outnew; 2684 } 2685 } 2686 2687 /* 2688 * requested block isn't allocated yet; 2689 * we couldn't try to create block if create flag is zero 2690 */ 2691 if (!create) { 2692 /* 2693 * put just found gap into cache to speed up 2694 * subsequent requests 2695 */ 2696 ext4_ext_put_gap_in_cache(inode, path, iblock); 2697 goto out2; 2698 } 2699 /* 2700 * Okay, we need to do block allocation. 2701 */ 2702 2703 /* find neighbour allocated blocks */ 2704 ar.lleft = iblock; 2705 err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft); 2706 if (err) 2707 goto out2; 2708 ar.lright = iblock; 2709 err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright); 2710 if (err) 2711 goto out2; 2712 2713 /* 2714 * See if request is beyond maximum number of blocks we can have in 2715 * a single extent. For an initialized extent this limit is 2716 * EXT_INIT_MAX_LEN and for an uninitialized extent this limit is 2717 * EXT_UNINIT_MAX_LEN. 2718 */ 2719 if (max_blocks > EXT_INIT_MAX_LEN && 2720 create != EXT4_CREATE_UNINITIALIZED_EXT) 2721 max_blocks = EXT_INIT_MAX_LEN; 2722 else if (max_blocks > EXT_UNINIT_MAX_LEN && 2723 create == EXT4_CREATE_UNINITIALIZED_EXT) 2724 max_blocks = EXT_UNINIT_MAX_LEN; 2725 2726 /* Check if we can really insert (iblock)::(iblock+max_blocks) extent */ 2727 newex.ee_block = cpu_to_le32(iblock); 2728 newex.ee_len = cpu_to_le16(max_blocks); 2729 err = ext4_ext_check_overlap(inode, &newex, path); 2730 if (err) 2731 allocated = ext4_ext_get_actual_len(&newex); 2732 else 2733 allocated = max_blocks; 2734 2735 /* allocate new block */ 2736 ar.inode = inode; 2737 ar.goal = ext4_ext_find_goal(inode, path, iblock); 2738 ar.logical = iblock; 2739 ar.len = allocated; 2740 if (S_ISREG(inode->i_mode)) 2741 ar.flags = EXT4_MB_HINT_DATA; 2742 else 2743 /* disable in-core preallocation for non-regular files */ 2744 ar.flags = 0; 2745 newblock = ext4_mb_new_blocks(handle, &ar, &err); 2746 if (!newblock) 2747 goto out2; 2748 ext_debug("allocate new block: goal %llu, found %llu/%lu\n", 2749 goal, newblock, allocated); 2750 2751 /* try to insert new extent into found leaf and return */ 2752 ext4_ext_store_pblock(&newex, newblock); 2753 newex.ee_len = cpu_to_le16(ar.len); 2754 if (create == EXT4_CREATE_UNINITIALIZED_EXT) /* Mark uninitialized */ 2755 ext4_ext_mark_uninitialized(&newex); 2756 err = ext4_ext_insert_extent(handle, inode, path, &newex); 2757 if (err) { 2758 /* free data blocks we just allocated */ 2759 /* not a good idea to call discard here directly, 2760 * but otherwise we'd need to call it every free() */ 2761 ext4_discard_preallocations(inode); 2762 ext4_free_blocks(handle, inode, ext_pblock(&newex), 2763 ext4_ext_get_actual_len(&newex), 0); 2764 goto out2; 2765 } 2766 2767 /* previous routine could use block we allocated */ 2768 newblock = ext_pblock(&newex); 2769 allocated = ext4_ext_get_actual_len(&newex); 2770outnew: 2771 if (extend_disksize) { 2772 disksize = ((loff_t) iblock + ar.len) << inode->i_blkbits; 2773 if (disksize > i_size_read(inode)) 2774 disksize = i_size_read(inode); 2775 if (disksize > EXT4_I(inode)->i_disksize) 2776 EXT4_I(inode)->i_disksize = disksize; 2777 } 2778 2779 set_buffer_new(bh_result); 2780 2781 /* Cache only when it is _not_ an uninitialized extent */ 2782 if (create != EXT4_CREATE_UNINITIALIZED_EXT) 2783 ext4_ext_put_in_cache(inode, iblock, allocated, newblock, 2784 EXT4_EXT_CACHE_EXTENT); 2785out: 2786 if (allocated > max_blocks) 2787 allocated = max_blocks; 2788 ext4_ext_show_leaf(inode, path); 2789 set_buffer_mapped(bh_result); 2790 bh_result->b_bdev = inode->i_sb->s_bdev; 2791 bh_result->b_blocknr = newblock; 2792out2: 2793 if (path) { 2794 ext4_ext_drop_refs(path); 2795 kfree(path); 2796 } 2797 return err ? err : allocated; 2798} 2799 2800void ext4_ext_truncate(struct inode *inode) 2801{ 2802 struct address_space *mapping = inode->i_mapping; 2803 struct super_block *sb = inode->i_sb; 2804 ext4_lblk_t last_block; 2805 handle_t *handle; 2806 int err = 0; 2807 2808 /* 2809 * probably first extent we're gonna free will be last in block 2810 */ 2811 err = ext4_writepage_trans_blocks(inode); 2812 handle = ext4_journal_start(inode, err); 2813 if (IS_ERR(handle)) 2814 return; 2815 2816 if (inode->i_size & (sb->s_blocksize - 1)) 2817 ext4_block_truncate_page(handle, mapping, inode->i_size); 2818 2819 if (ext4_orphan_add(handle, inode)) 2820 goto out_stop; 2821 2822 down_write(&EXT4_I(inode)->i_data_sem); 2823 ext4_ext_invalidate_cache(inode); 2824 2825 ext4_discard_preallocations(inode); 2826 2827 /* 2828 * TODO: optimization is possible here. 2829 * Probably we need not scan at all, 2830 * because page truncation is enough. 2831 */ 2832 2833 /* we have to know where to truncate from in crash case */ 2834 EXT4_I(inode)->i_disksize = inode->i_size; 2835 ext4_mark_inode_dirty(handle, inode); 2836 2837 last_block = (inode->i_size + sb->s_blocksize - 1) 2838 >> EXT4_BLOCK_SIZE_BITS(sb); 2839 err = ext4_ext_remove_space(inode, last_block); 2840 2841 /* In a multi-transaction truncate, we only make the final 2842 * transaction synchronous. 2843 */ 2844 if (IS_SYNC(inode)) 2845 handle->h_sync = 1; 2846 2847out_stop: 2848 up_write(&EXT4_I(inode)->i_data_sem); 2849 /* 2850 * If this was a simple ftruncate() and the file will remain alive, 2851 * then we need to clear up the orphan record which we created above. 2852 * However, if this was a real unlink then we were called by 2853 * ext4_delete_inode(), and we allow that function to clean up the 2854 * orphan info for us. 2855 */ 2856 if (inode->i_nlink) 2857 ext4_orphan_del(handle, inode); 2858 2859 inode->i_mtime = inode->i_ctime = ext4_current_time(inode); 2860 ext4_mark_inode_dirty(handle, inode); 2861 ext4_journal_stop(handle); 2862} 2863 2864static void ext4_falloc_update_inode(struct inode *inode, 2865 int mode, loff_t new_size, int update_ctime) 2866{ 2867 struct timespec now; 2868 2869 if (update_ctime) { 2870 now = current_fs_time(inode->i_sb); 2871 if (!timespec_equal(&inode->i_ctime, &now)) 2872 inode->i_ctime = now; 2873 } 2874 /* 2875 * Update only when preallocation was requested beyond 2876 * the file size. 2877 */ 2878 if (!(mode & FALLOC_FL_KEEP_SIZE)) { 2879 if (new_size > i_size_read(inode)) 2880 i_size_write(inode, new_size); 2881 if (new_size > EXT4_I(inode)->i_disksize) 2882 ext4_update_i_disksize(inode, new_size); 2883 } 2884 2885} 2886 2887/* 2888 * preallocate space for a file. This implements ext4's fallocate inode 2889 * operation, which gets called from sys_fallocate system call. 2890 * For block-mapped files, posix_fallocate should fall back to the method 2891 * of writing zeroes to the required new blocks (the same behavior which is 2892 * expected for file systems which do not support fallocate() system call). 2893 */ 2894long ext4_fallocate(struct inode *inode, int mode, loff_t offset, loff_t len) 2895{ 2896 handle_t *handle; 2897 ext4_lblk_t block; 2898 loff_t new_size; 2899 unsigned long max_blocks; 2900 int ret = 0; 2901 int ret2 = 0; 2902 int retries = 0; 2903 struct buffer_head map_bh; 2904 unsigned int credits, blkbits = inode->i_blkbits; 2905 2906 /* 2907 * currently supporting (pre)allocate mode for extent-based 2908 * files _only_ 2909 */ 2910 if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) 2911 return -EOPNOTSUPP; 2912 2913 /* preallocation to directories is currently not supported */ 2914 if (S_ISDIR(inode->i_mode)) 2915 return -ENODEV; 2916 2917 block = offset >> blkbits; 2918 /* 2919 * We can't just convert len to max_blocks because 2920 * If blocksize = 4096 offset = 3072 and len = 2048 2921 */ 2922 max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits) 2923 - block; 2924 /* 2925 * credits to insert 1 extent into extent tree 2926 */ 2927 credits = ext4_chunk_trans_blocks(inode, max_blocks); 2928 mutex_lock(&inode->i_mutex); 2929retry: 2930 while (ret >= 0 && ret < max_blocks) { 2931 block = block + ret; 2932 max_blocks = max_blocks - ret; 2933 handle = ext4_journal_start(inode, credits); 2934 if (IS_ERR(handle)) { 2935 ret = PTR_ERR(handle); 2936 break; 2937 } 2938 ret = ext4_get_blocks_wrap(handle, inode, block, 2939 max_blocks, &map_bh, 2940 EXT4_CREATE_UNINITIALIZED_EXT, 0, 0); 2941 if (ret <= 0) { 2942#ifdef EXT4FS_DEBUG 2943 WARN_ON(ret <= 0); 2944 printk(KERN_ERR "%s: ext4_ext_get_blocks " 2945 "returned error inode#%lu, block=%u, " 2946 "max_blocks=%lu", __func__, 2947 inode->i_ino, block, max_blocks); 2948#endif 2949 ext4_mark_inode_dirty(handle, inode); 2950 ret2 = ext4_journal_stop(handle); 2951 break; 2952 } 2953 if ((block + ret) >= (EXT4_BLOCK_ALIGN(offset + len, 2954 blkbits) >> blkbits)) 2955 new_size = offset + len; 2956 else 2957 new_size = (block + ret) << blkbits; 2958 2959 ext4_falloc_update_inode(inode, mode, new_size, 2960 buffer_new(&map_bh)); 2961 ext4_mark_inode_dirty(handle, inode); 2962 ret2 = ext4_journal_stop(handle); 2963 if (ret2) 2964 break; 2965 } 2966 if (ret == -ENOSPC && 2967 ext4_should_retry_alloc(inode->i_sb, &retries)) { 2968 ret = 0; 2969 goto retry; 2970 } 2971 mutex_unlock(&inode->i_mutex); 2972 return ret > 0 ? ret2 : ret; 2973} 2974