extents.c revision 9102e4fa8016af8bf1a263df913ee8fdafd4dfb0
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) 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 182static ext4_fsblk_t 183ext4_ext_new_block(handle_t *handle, struct inode *inode, 184 struct ext4_ext_path *path, 185 struct ext4_extent *ex, int *err) 186{ 187 ext4_fsblk_t goal, newblock; 188 189 goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block)); 190 newblock = ext4_new_block(handle, inode, goal, err); 191 return newblock; 192} 193 194static int ext4_ext_space_block(struct inode *inode) 195{ 196 int size; 197 198 size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header)) 199 / sizeof(struct ext4_extent); 200#ifdef AGGRESSIVE_TEST 201 if (size > 6) 202 size = 6; 203#endif 204 return size; 205} 206 207static int ext4_ext_space_block_idx(struct inode *inode) 208{ 209 int size; 210 211 size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header)) 212 / sizeof(struct ext4_extent_idx); 213#ifdef AGGRESSIVE_TEST 214 if (size > 5) 215 size = 5; 216#endif 217 return size; 218} 219 220static int ext4_ext_space_root(struct inode *inode) 221{ 222 int size; 223 224 size = sizeof(EXT4_I(inode)->i_data); 225 size -= sizeof(struct ext4_extent_header); 226 size /= sizeof(struct ext4_extent); 227#ifdef AGGRESSIVE_TEST 228 if (size > 3) 229 size = 3; 230#endif 231 return size; 232} 233 234static int ext4_ext_space_root_idx(struct inode *inode) 235{ 236 int size; 237 238 size = sizeof(EXT4_I(inode)->i_data); 239 size -= sizeof(struct ext4_extent_header); 240 size /= sizeof(struct ext4_extent_idx); 241#ifdef AGGRESSIVE_TEST 242 if (size > 4) 243 size = 4; 244#endif 245 return size; 246} 247 248static int 249ext4_ext_max_entries(struct inode *inode, int depth) 250{ 251 int max; 252 253 if (depth == ext_depth(inode)) { 254 if (depth == 0) 255 max = ext4_ext_space_root(inode); 256 else 257 max = ext4_ext_space_root_idx(inode); 258 } else { 259 if (depth == 0) 260 max = ext4_ext_space_block(inode); 261 else 262 max = ext4_ext_space_block_idx(inode); 263 } 264 265 return max; 266} 267 268static int __ext4_ext_check_header(const char *function, struct inode *inode, 269 struct ext4_extent_header *eh, 270 int depth) 271{ 272 const char *error_msg; 273 int max = 0; 274 275 if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) { 276 error_msg = "invalid magic"; 277 goto corrupted; 278 } 279 if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) { 280 error_msg = "unexpected eh_depth"; 281 goto corrupted; 282 } 283 if (unlikely(eh->eh_max == 0)) { 284 error_msg = "invalid eh_max"; 285 goto corrupted; 286 } 287 max = ext4_ext_max_entries(inode, depth); 288 if (unlikely(le16_to_cpu(eh->eh_max) > max)) { 289 error_msg = "too large eh_max"; 290 goto corrupted; 291 } 292 if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) { 293 error_msg = "invalid eh_entries"; 294 goto corrupted; 295 } 296 return 0; 297 298corrupted: 299 ext4_error(inode->i_sb, function, 300 "bad header in inode #%lu: %s - magic %x, " 301 "entries %u, max %u(%u), depth %u(%u)", 302 inode->i_ino, error_msg, le16_to_cpu(eh->eh_magic), 303 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max), 304 max, le16_to_cpu(eh->eh_depth), depth); 305 306 return -EIO; 307} 308 309#define ext4_ext_check_header(inode, eh, depth) \ 310 __ext4_ext_check_header(__func__, inode, eh, depth) 311 312#ifdef EXT_DEBUG 313static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path) 314{ 315 int k, l = path->p_depth; 316 317 ext_debug("path:"); 318 for (k = 0; k <= l; k++, path++) { 319 if (path->p_idx) { 320 ext_debug(" %d->%llu", le32_to_cpu(path->p_idx->ei_block), 321 idx_pblock(path->p_idx)); 322 } else if (path->p_ext) { 323 ext_debug(" %d:%d:%llu ", 324 le32_to_cpu(path->p_ext->ee_block), 325 ext4_ext_get_actual_len(path->p_ext), 326 ext_pblock(path->p_ext)); 327 } else 328 ext_debug(" []"); 329 } 330 ext_debug("\n"); 331} 332 333static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path) 334{ 335 int depth = ext_depth(inode); 336 struct ext4_extent_header *eh; 337 struct ext4_extent *ex; 338 int i; 339 340 if (!path) 341 return; 342 343 eh = path[depth].p_hdr; 344 ex = EXT_FIRST_EXTENT(eh); 345 346 for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) { 347 ext_debug("%d:%d:%llu ", le32_to_cpu(ex->ee_block), 348 ext4_ext_get_actual_len(ex), ext_pblock(ex)); 349 } 350 ext_debug("\n"); 351} 352#else 353#define ext4_ext_show_path(inode,path) 354#define ext4_ext_show_leaf(inode,path) 355#endif 356 357void ext4_ext_drop_refs(struct ext4_ext_path *path) 358{ 359 int depth = path->p_depth; 360 int i; 361 362 for (i = 0; i <= depth; i++, path++) 363 if (path->p_bh) { 364 brelse(path->p_bh); 365 path->p_bh = NULL; 366 } 367} 368 369/* 370 * ext4_ext_binsearch_idx: 371 * binary search for the closest index of the given block 372 * the header must be checked before calling this 373 */ 374static void 375ext4_ext_binsearch_idx(struct inode *inode, 376 struct ext4_ext_path *path, ext4_lblk_t block) 377{ 378 struct ext4_extent_header *eh = path->p_hdr; 379 struct ext4_extent_idx *r, *l, *m; 380 381 382 ext_debug("binsearch for %u(idx): ", block); 383 384 l = EXT_FIRST_INDEX(eh) + 1; 385 r = EXT_LAST_INDEX(eh); 386 while (l <= r) { 387 m = l + (r - l) / 2; 388 if (block < le32_to_cpu(m->ei_block)) 389 r = m - 1; 390 else 391 l = m + 1; 392 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ei_block), 393 m, le32_to_cpu(m->ei_block), 394 r, le32_to_cpu(r->ei_block)); 395 } 396 397 path->p_idx = l - 1; 398 ext_debug(" -> %d->%lld ", le32_to_cpu(path->p_idx->ei_block), 399 idx_pblock(path->p_idx)); 400 401#ifdef CHECK_BINSEARCH 402 { 403 struct ext4_extent_idx *chix, *ix; 404 int k; 405 406 chix = ix = EXT_FIRST_INDEX(eh); 407 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) { 408 if (k != 0 && 409 le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) { 410 printk("k=%d, ix=0x%p, first=0x%p\n", k, 411 ix, EXT_FIRST_INDEX(eh)); 412 printk("%u <= %u\n", 413 le32_to_cpu(ix->ei_block), 414 le32_to_cpu(ix[-1].ei_block)); 415 } 416 BUG_ON(k && le32_to_cpu(ix->ei_block) 417 <= le32_to_cpu(ix[-1].ei_block)); 418 if (block < le32_to_cpu(ix->ei_block)) 419 break; 420 chix = ix; 421 } 422 BUG_ON(chix != path->p_idx); 423 } 424#endif 425 426} 427 428/* 429 * ext4_ext_binsearch: 430 * binary search for closest extent of the given block 431 * the header must be checked before calling this 432 */ 433static void 434ext4_ext_binsearch(struct inode *inode, 435 struct ext4_ext_path *path, ext4_lblk_t block) 436{ 437 struct ext4_extent_header *eh = path->p_hdr; 438 struct ext4_extent *r, *l, *m; 439 440 if (eh->eh_entries == 0) { 441 /* 442 * this leaf is empty: 443 * we get such a leaf in split/add case 444 */ 445 return; 446 } 447 448 ext_debug("binsearch for %u: ", block); 449 450 l = EXT_FIRST_EXTENT(eh) + 1; 451 r = EXT_LAST_EXTENT(eh); 452 453 while (l <= r) { 454 m = l + (r - l) / 2; 455 if (block < le32_to_cpu(m->ee_block)) 456 r = m - 1; 457 else 458 l = m + 1; 459 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ee_block), 460 m, le32_to_cpu(m->ee_block), 461 r, le32_to_cpu(r->ee_block)); 462 } 463 464 path->p_ext = l - 1; 465 ext_debug(" -> %d:%llu:%d ", 466 le32_to_cpu(path->p_ext->ee_block), 467 ext_pblock(path->p_ext), 468 ext4_ext_get_actual_len(path->p_ext)); 469 470#ifdef CHECK_BINSEARCH 471 { 472 struct ext4_extent *chex, *ex; 473 int k; 474 475 chex = ex = EXT_FIRST_EXTENT(eh); 476 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) { 477 BUG_ON(k && le32_to_cpu(ex->ee_block) 478 <= le32_to_cpu(ex[-1].ee_block)); 479 if (block < le32_to_cpu(ex->ee_block)) 480 break; 481 chex = ex; 482 } 483 BUG_ON(chex != path->p_ext); 484 } 485#endif 486 487} 488 489int ext4_ext_tree_init(handle_t *handle, struct inode *inode) 490{ 491 struct ext4_extent_header *eh; 492 493 eh = ext_inode_hdr(inode); 494 eh->eh_depth = 0; 495 eh->eh_entries = 0; 496 eh->eh_magic = EXT4_EXT_MAGIC; 497 eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode)); 498 ext4_mark_inode_dirty(handle, inode); 499 ext4_ext_invalidate_cache(inode); 500 return 0; 501} 502 503struct ext4_ext_path * 504ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block, 505 struct ext4_ext_path *path) 506{ 507 struct ext4_extent_header *eh; 508 struct buffer_head *bh; 509 short int depth, i, ppos = 0, alloc = 0; 510 511 eh = ext_inode_hdr(inode); 512 depth = ext_depth(inode); 513 if (ext4_ext_check_header(inode, eh, depth)) 514 return ERR_PTR(-EIO); 515 516 517 /* account possible depth increase */ 518 if (!path) { 519 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2), 520 GFP_NOFS); 521 if (!path) 522 return ERR_PTR(-ENOMEM); 523 alloc = 1; 524 } 525 path[0].p_hdr = eh; 526 path[0].p_bh = NULL; 527 528 i = depth; 529 /* walk through the tree */ 530 while (i) { 531 ext_debug("depth %d: num %d, max %d\n", 532 ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max)); 533 534 ext4_ext_binsearch_idx(inode, path + ppos, block); 535 path[ppos].p_block = idx_pblock(path[ppos].p_idx); 536 path[ppos].p_depth = i; 537 path[ppos].p_ext = NULL; 538 539 bh = sb_bread(inode->i_sb, path[ppos].p_block); 540 if (!bh) 541 goto err; 542 543 eh = ext_block_hdr(bh); 544 ppos++; 545 BUG_ON(ppos > depth); 546 path[ppos].p_bh = bh; 547 path[ppos].p_hdr = eh; 548 i--; 549 550 if (ext4_ext_check_header(inode, eh, i)) 551 goto err; 552 } 553 554 path[ppos].p_depth = i; 555 path[ppos].p_ext = NULL; 556 path[ppos].p_idx = NULL; 557 558 /* find extent */ 559 ext4_ext_binsearch(inode, path + ppos, block); 560 /* if not an empty leaf */ 561 if (path[ppos].p_ext) 562 path[ppos].p_block = ext_pblock(path[ppos].p_ext); 563 564 ext4_ext_show_path(inode, path); 565 566 return path; 567 568err: 569 ext4_ext_drop_refs(path); 570 if (alloc) 571 kfree(path); 572 return ERR_PTR(-EIO); 573} 574 575/* 576 * ext4_ext_insert_index: 577 * insert new index [@logical;@ptr] into the block at @curp; 578 * check where to insert: before @curp or after @curp 579 */ 580static int ext4_ext_insert_index(handle_t *handle, struct inode *inode, 581 struct ext4_ext_path *curp, 582 int logical, ext4_fsblk_t ptr) 583{ 584 struct ext4_extent_idx *ix; 585 int len, err; 586 587 err = ext4_ext_get_access(handle, inode, curp); 588 if (err) 589 return err; 590 591 BUG_ON(logical == le32_to_cpu(curp->p_idx->ei_block)); 592 len = EXT_MAX_INDEX(curp->p_hdr) - curp->p_idx; 593 if (logical > le32_to_cpu(curp->p_idx->ei_block)) { 594 /* insert after */ 595 if (curp->p_idx != EXT_LAST_INDEX(curp->p_hdr)) { 596 len = (len - 1) * sizeof(struct ext4_extent_idx); 597 len = len < 0 ? 0 : len; 598 ext_debug("insert new index %d after: %llu. " 599 "move %d from 0x%p to 0x%p\n", 600 logical, ptr, len, 601 (curp->p_idx + 1), (curp->p_idx + 2)); 602 memmove(curp->p_idx + 2, curp->p_idx + 1, len); 603 } 604 ix = curp->p_idx + 1; 605 } else { 606 /* insert before */ 607 len = len * sizeof(struct ext4_extent_idx); 608 len = len < 0 ? 0 : len; 609 ext_debug("insert new index %d before: %llu. " 610 "move %d from 0x%p to 0x%p\n", 611 logical, ptr, len, 612 curp->p_idx, (curp->p_idx + 1)); 613 memmove(curp->p_idx + 1, curp->p_idx, len); 614 ix = curp->p_idx; 615 } 616 617 ix->ei_block = cpu_to_le32(logical); 618 ext4_idx_store_pblock(ix, ptr); 619 le16_add_cpu(&curp->p_hdr->eh_entries, 1); 620 621 BUG_ON(le16_to_cpu(curp->p_hdr->eh_entries) 622 > le16_to_cpu(curp->p_hdr->eh_max)); 623 BUG_ON(ix > EXT_LAST_INDEX(curp->p_hdr)); 624 625 err = ext4_ext_dirty(handle, inode, curp); 626 ext4_std_error(inode->i_sb, err); 627 628 return err; 629} 630 631/* 632 * ext4_ext_split: 633 * inserts new subtree into the path, using free index entry 634 * at depth @at: 635 * - allocates all needed blocks (new leaf and all intermediate index blocks) 636 * - makes decision where to split 637 * - moves remaining extents and index entries (right to the split point) 638 * into the newly allocated blocks 639 * - initializes subtree 640 */ 641static int ext4_ext_split(handle_t *handle, struct inode *inode, 642 struct ext4_ext_path *path, 643 struct ext4_extent *newext, int at) 644{ 645 struct buffer_head *bh = NULL; 646 int depth = ext_depth(inode); 647 struct ext4_extent_header *neh; 648 struct ext4_extent_idx *fidx; 649 struct ext4_extent *ex; 650 int i = at, k, m, a; 651 ext4_fsblk_t newblock, oldblock; 652 __le32 border; 653 ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */ 654 int err = 0; 655 656 /* make decision: where to split? */ 657 /* FIXME: now decision is simplest: at current extent */ 658 659 /* if current leaf will be split, then we should use 660 * border from split point */ 661 BUG_ON(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr)); 662 if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) { 663 border = path[depth].p_ext[1].ee_block; 664 ext_debug("leaf will be split." 665 " next leaf starts at %d\n", 666 le32_to_cpu(border)); 667 } else { 668 border = newext->ee_block; 669 ext_debug("leaf will be added." 670 " next leaf starts at %d\n", 671 le32_to_cpu(border)); 672 } 673 674 /* 675 * If error occurs, then we break processing 676 * and mark filesystem read-only. index won't 677 * be inserted and tree will be in consistent 678 * state. Next mount will repair buffers too. 679 */ 680 681 /* 682 * Get array to track all allocated blocks. 683 * We need this to handle errors and free blocks 684 * upon them. 685 */ 686 ablocks = kzalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS); 687 if (!ablocks) 688 return -ENOMEM; 689 690 /* allocate all needed blocks */ 691 ext_debug("allocate %d blocks for indexes/leaf\n", depth - at); 692 for (a = 0; a < depth - at; a++) { 693 newblock = ext4_ext_new_block(handle, inode, path, newext, &err); 694 if (newblock == 0) 695 goto cleanup; 696 ablocks[a] = newblock; 697 } 698 699 /* initialize new leaf */ 700 newblock = ablocks[--a]; 701 BUG_ON(newblock == 0); 702 bh = sb_getblk(inode->i_sb, newblock); 703 if (!bh) { 704 err = -EIO; 705 goto cleanup; 706 } 707 lock_buffer(bh); 708 709 err = ext4_journal_get_create_access(handle, bh); 710 if (err) 711 goto cleanup; 712 713 neh = ext_block_hdr(bh); 714 neh->eh_entries = 0; 715 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode)); 716 neh->eh_magic = EXT4_EXT_MAGIC; 717 neh->eh_depth = 0; 718 ex = EXT_FIRST_EXTENT(neh); 719 720 /* move remainder of path[depth] to the new leaf */ 721 BUG_ON(path[depth].p_hdr->eh_entries != path[depth].p_hdr->eh_max); 722 /* start copy from next extent */ 723 /* TODO: we could do it by single memmove */ 724 m = 0; 725 path[depth].p_ext++; 726 while (path[depth].p_ext <= 727 EXT_MAX_EXTENT(path[depth].p_hdr)) { 728 ext_debug("move %d:%llu:%d in new leaf %llu\n", 729 le32_to_cpu(path[depth].p_ext->ee_block), 730 ext_pblock(path[depth].p_ext), 731 ext4_ext_get_actual_len(path[depth].p_ext), 732 newblock); 733 /*memmove(ex++, path[depth].p_ext++, 734 sizeof(struct ext4_extent)); 735 neh->eh_entries++;*/ 736 path[depth].p_ext++; 737 m++; 738 } 739 if (m) { 740 memmove(ex, path[depth].p_ext-m, sizeof(struct ext4_extent)*m); 741 le16_add_cpu(&neh->eh_entries, m); 742 } 743 744 set_buffer_uptodate(bh); 745 unlock_buffer(bh); 746 747 err = ext4_journal_dirty_metadata(handle, bh); 748 if (err) 749 goto cleanup; 750 brelse(bh); 751 bh = NULL; 752 753 /* correct old leaf */ 754 if (m) { 755 err = ext4_ext_get_access(handle, inode, path + depth); 756 if (err) 757 goto cleanup; 758 le16_add_cpu(&path[depth].p_hdr->eh_entries, -m); 759 err = ext4_ext_dirty(handle, inode, path + depth); 760 if (err) 761 goto cleanup; 762 763 } 764 765 /* create intermediate indexes */ 766 k = depth - at - 1; 767 BUG_ON(k < 0); 768 if (k) 769 ext_debug("create %d intermediate indices\n", k); 770 /* insert new index into current index block */ 771 /* current depth stored in i var */ 772 i = depth - 1; 773 while (k--) { 774 oldblock = newblock; 775 newblock = ablocks[--a]; 776 bh = sb_getblk(inode->i_sb, newblock); 777 if (!bh) { 778 err = -EIO; 779 goto cleanup; 780 } 781 lock_buffer(bh); 782 783 err = ext4_journal_get_create_access(handle, bh); 784 if (err) 785 goto cleanup; 786 787 neh = ext_block_hdr(bh); 788 neh->eh_entries = cpu_to_le16(1); 789 neh->eh_magic = EXT4_EXT_MAGIC; 790 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode)); 791 neh->eh_depth = cpu_to_le16(depth - i); 792 fidx = EXT_FIRST_INDEX(neh); 793 fidx->ei_block = border; 794 ext4_idx_store_pblock(fidx, oldblock); 795 796 ext_debug("int.index at %d (block %llu): %u -> %llu\n", 797 i, newblock, le32_to_cpu(border), oldblock); 798 /* copy indexes */ 799 m = 0; 800 path[i].p_idx++; 801 802 ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx, 803 EXT_MAX_INDEX(path[i].p_hdr)); 804 BUG_ON(EXT_MAX_INDEX(path[i].p_hdr) != 805 EXT_LAST_INDEX(path[i].p_hdr)); 806 while (path[i].p_idx <= EXT_MAX_INDEX(path[i].p_hdr)) { 807 ext_debug("%d: move %d:%llu in new index %llu\n", i, 808 le32_to_cpu(path[i].p_idx->ei_block), 809 idx_pblock(path[i].p_idx), 810 newblock); 811 /*memmove(++fidx, path[i].p_idx++, 812 sizeof(struct ext4_extent_idx)); 813 neh->eh_entries++; 814 BUG_ON(neh->eh_entries > neh->eh_max);*/ 815 path[i].p_idx++; 816 m++; 817 } 818 if (m) { 819 memmove(++fidx, path[i].p_idx - m, 820 sizeof(struct ext4_extent_idx) * m); 821 le16_add_cpu(&neh->eh_entries, m); 822 } 823 set_buffer_uptodate(bh); 824 unlock_buffer(bh); 825 826 err = ext4_journal_dirty_metadata(handle, bh); 827 if (err) 828 goto cleanup; 829 brelse(bh); 830 bh = NULL; 831 832 /* correct old index */ 833 if (m) { 834 err = ext4_ext_get_access(handle, inode, path + i); 835 if (err) 836 goto cleanup; 837 le16_add_cpu(&path[i].p_hdr->eh_entries, -m); 838 err = ext4_ext_dirty(handle, inode, path + i); 839 if (err) 840 goto cleanup; 841 } 842 843 i--; 844 } 845 846 /* insert new index */ 847 err = ext4_ext_insert_index(handle, inode, path + at, 848 le32_to_cpu(border), newblock); 849 850cleanup: 851 if (bh) { 852 if (buffer_locked(bh)) 853 unlock_buffer(bh); 854 brelse(bh); 855 } 856 857 if (err) { 858 /* free all allocated blocks in error case */ 859 for (i = 0; i < depth; i++) { 860 if (!ablocks[i]) 861 continue; 862 ext4_free_blocks(handle, inode, ablocks[i], 1, 1); 863 } 864 } 865 kfree(ablocks); 866 867 return err; 868} 869 870/* 871 * ext4_ext_grow_indepth: 872 * implements tree growing procedure: 873 * - allocates new block 874 * - moves top-level data (index block or leaf) into the new block 875 * - initializes new top-level, creating index that points to the 876 * just created block 877 */ 878static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode, 879 struct ext4_ext_path *path, 880 struct ext4_extent *newext) 881{ 882 struct ext4_ext_path *curp = path; 883 struct ext4_extent_header *neh; 884 struct ext4_extent_idx *fidx; 885 struct buffer_head *bh; 886 ext4_fsblk_t newblock; 887 int err = 0; 888 889 newblock = ext4_ext_new_block(handle, inode, path, newext, &err); 890 if (newblock == 0) 891 return err; 892 893 bh = sb_getblk(inode->i_sb, newblock); 894 if (!bh) { 895 err = -EIO; 896 ext4_std_error(inode->i_sb, err); 897 return err; 898 } 899 lock_buffer(bh); 900 901 err = ext4_journal_get_create_access(handle, bh); 902 if (err) { 903 unlock_buffer(bh); 904 goto out; 905 } 906 907 /* move top-level index/leaf into new block */ 908 memmove(bh->b_data, curp->p_hdr, sizeof(EXT4_I(inode)->i_data)); 909 910 /* set size of new block */ 911 neh = ext_block_hdr(bh); 912 /* old root could have indexes or leaves 913 * so calculate e_max right way */ 914 if (ext_depth(inode)) 915 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode)); 916 else 917 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode)); 918 neh->eh_magic = EXT4_EXT_MAGIC; 919 set_buffer_uptodate(bh); 920 unlock_buffer(bh); 921 922 err = ext4_journal_dirty_metadata(handle, bh); 923 if (err) 924 goto out; 925 926 /* create index in new top-level index: num,max,pointer */ 927 err = ext4_ext_get_access(handle, inode, curp); 928 if (err) 929 goto out; 930 931 curp->p_hdr->eh_magic = EXT4_EXT_MAGIC; 932 curp->p_hdr->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode)); 933 curp->p_hdr->eh_entries = cpu_to_le16(1); 934 curp->p_idx = EXT_FIRST_INDEX(curp->p_hdr); 935 936 if (path[0].p_hdr->eh_depth) 937 curp->p_idx->ei_block = 938 EXT_FIRST_INDEX(path[0].p_hdr)->ei_block; 939 else 940 curp->p_idx->ei_block = 941 EXT_FIRST_EXTENT(path[0].p_hdr)->ee_block; 942 ext4_idx_store_pblock(curp->p_idx, newblock); 943 944 neh = ext_inode_hdr(inode); 945 fidx = EXT_FIRST_INDEX(neh); 946 ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n", 947 le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max), 948 le32_to_cpu(fidx->ei_block), idx_pblock(fidx)); 949 950 neh->eh_depth = cpu_to_le16(path->p_depth + 1); 951 err = ext4_ext_dirty(handle, inode, curp); 952out: 953 brelse(bh); 954 955 return err; 956} 957 958/* 959 * ext4_ext_create_new_leaf: 960 * finds empty index and adds new leaf. 961 * if no free index is found, then it requests in-depth growing. 962 */ 963static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode, 964 struct ext4_ext_path *path, 965 struct ext4_extent *newext) 966{ 967 struct ext4_ext_path *curp; 968 int depth, i, err = 0; 969 970repeat: 971 i = depth = ext_depth(inode); 972 973 /* walk up to the tree and look for free index entry */ 974 curp = path + depth; 975 while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) { 976 i--; 977 curp--; 978 } 979 980 /* we use already allocated block for index block, 981 * so subsequent data blocks should be contiguous */ 982 if (EXT_HAS_FREE_INDEX(curp)) { 983 /* if we found index with free entry, then use that 984 * entry: create all needed subtree and add new leaf */ 985 err = ext4_ext_split(handle, inode, path, newext, i); 986 if (err) 987 goto out; 988 989 /* refill path */ 990 ext4_ext_drop_refs(path); 991 path = ext4_ext_find_extent(inode, 992 (ext4_lblk_t)le32_to_cpu(newext->ee_block), 993 path); 994 if (IS_ERR(path)) 995 err = PTR_ERR(path); 996 } else { 997 /* tree is full, time to grow in depth */ 998 err = ext4_ext_grow_indepth(handle, inode, path, newext); 999 if (err) 1000 goto out; 1001 1002 /* refill path */ 1003 ext4_ext_drop_refs(path); 1004 path = ext4_ext_find_extent(inode, 1005 (ext4_lblk_t)le32_to_cpu(newext->ee_block), 1006 path); 1007 if (IS_ERR(path)) { 1008 err = PTR_ERR(path); 1009 goto out; 1010 } 1011 1012 /* 1013 * only first (depth 0 -> 1) produces free space; 1014 * in all other cases we have to split the grown tree 1015 */ 1016 depth = ext_depth(inode); 1017 if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) { 1018 /* now we need to split */ 1019 goto repeat; 1020 } 1021 } 1022 1023out: 1024 return err; 1025} 1026 1027/* 1028 * search the closest allocated block to the left for *logical 1029 * and returns it at @logical + it's physical address at @phys 1030 * if *logical is the smallest allocated block, the function 1031 * returns 0 at @phys 1032 * return value contains 0 (success) or error code 1033 */ 1034int 1035ext4_ext_search_left(struct inode *inode, struct ext4_ext_path *path, 1036 ext4_lblk_t *logical, ext4_fsblk_t *phys) 1037{ 1038 struct ext4_extent_idx *ix; 1039 struct ext4_extent *ex; 1040 int depth, ee_len; 1041 1042 BUG_ON(path == NULL); 1043 depth = path->p_depth; 1044 *phys = 0; 1045 1046 if (depth == 0 && path->p_ext == NULL) 1047 return 0; 1048 1049 /* usually extent in the path covers blocks smaller 1050 * then *logical, but it can be that extent is the 1051 * first one in the file */ 1052 1053 ex = path[depth].p_ext; 1054 ee_len = ext4_ext_get_actual_len(ex); 1055 if (*logical < le32_to_cpu(ex->ee_block)) { 1056 BUG_ON(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex); 1057 while (--depth >= 0) { 1058 ix = path[depth].p_idx; 1059 BUG_ON(ix != EXT_FIRST_INDEX(path[depth].p_hdr)); 1060 } 1061 return 0; 1062 } 1063 1064 BUG_ON(*logical < (le32_to_cpu(ex->ee_block) + ee_len)); 1065 1066 *logical = le32_to_cpu(ex->ee_block) + ee_len - 1; 1067 *phys = ext_pblock(ex) + ee_len - 1; 1068 return 0; 1069} 1070 1071/* 1072 * search the closest allocated block to the right for *logical 1073 * and returns it at @logical + it's physical address at @phys 1074 * if *logical is the smallest allocated block, the function 1075 * returns 0 at @phys 1076 * return value contains 0 (success) or error code 1077 */ 1078int 1079ext4_ext_search_right(struct inode *inode, struct ext4_ext_path *path, 1080 ext4_lblk_t *logical, ext4_fsblk_t *phys) 1081{ 1082 struct buffer_head *bh = NULL; 1083 struct ext4_extent_header *eh; 1084 struct ext4_extent_idx *ix; 1085 struct ext4_extent *ex; 1086 ext4_fsblk_t block; 1087 int depth, ee_len; 1088 1089 BUG_ON(path == NULL); 1090 depth = path->p_depth; 1091 *phys = 0; 1092 1093 if (depth == 0 && path->p_ext == NULL) 1094 return 0; 1095 1096 /* usually extent in the path covers blocks smaller 1097 * then *logical, but it can be that extent is the 1098 * first one in the file */ 1099 1100 ex = path[depth].p_ext; 1101 ee_len = ext4_ext_get_actual_len(ex); 1102 if (*logical < le32_to_cpu(ex->ee_block)) { 1103 BUG_ON(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex); 1104 while (--depth >= 0) { 1105 ix = path[depth].p_idx; 1106 BUG_ON(ix != EXT_FIRST_INDEX(path[depth].p_hdr)); 1107 } 1108 *logical = le32_to_cpu(ex->ee_block); 1109 *phys = ext_pblock(ex); 1110 return 0; 1111 } 1112 1113 BUG_ON(*logical < (le32_to_cpu(ex->ee_block) + ee_len)); 1114 1115 if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) { 1116 /* next allocated block in this leaf */ 1117 ex++; 1118 *logical = le32_to_cpu(ex->ee_block); 1119 *phys = ext_pblock(ex); 1120 return 0; 1121 } 1122 1123 /* go up and search for index to the right */ 1124 while (--depth >= 0) { 1125 ix = path[depth].p_idx; 1126 if (ix != EXT_LAST_INDEX(path[depth].p_hdr)) 1127 break; 1128 } 1129 1130 if (depth < 0) { 1131 /* we've gone up to the root and 1132 * found no index to the right */ 1133 return 0; 1134 } 1135 1136 /* we've found index to the right, let's 1137 * follow it and find the closest allocated 1138 * block to the right */ 1139 ix++; 1140 block = idx_pblock(ix); 1141 while (++depth < path->p_depth) { 1142 bh = sb_bread(inode->i_sb, block); 1143 if (bh == NULL) 1144 return -EIO; 1145 eh = ext_block_hdr(bh); 1146 if (ext4_ext_check_header(inode, eh, depth)) { 1147 put_bh(bh); 1148 return -EIO; 1149 } 1150 ix = EXT_FIRST_INDEX(eh); 1151 block = idx_pblock(ix); 1152 put_bh(bh); 1153 } 1154 1155 bh = sb_bread(inode->i_sb, block); 1156 if (bh == NULL) 1157 return -EIO; 1158 eh = ext_block_hdr(bh); 1159 if (ext4_ext_check_header(inode, eh, path->p_depth - depth)) { 1160 put_bh(bh); 1161 return -EIO; 1162 } 1163 ex = EXT_FIRST_EXTENT(eh); 1164 *logical = le32_to_cpu(ex->ee_block); 1165 *phys = ext_pblock(ex); 1166 put_bh(bh); 1167 return 0; 1168 1169} 1170 1171/* 1172 * ext4_ext_next_allocated_block: 1173 * returns allocated block in subsequent extent or EXT_MAX_BLOCK. 1174 * NOTE: it considers block number from index entry as 1175 * allocated block. Thus, index entries have to be consistent 1176 * with leaves. 1177 */ 1178static ext4_lblk_t 1179ext4_ext_next_allocated_block(struct ext4_ext_path *path) 1180{ 1181 int depth; 1182 1183 BUG_ON(path == NULL); 1184 depth = path->p_depth; 1185 1186 if (depth == 0 && path->p_ext == NULL) 1187 return EXT_MAX_BLOCK; 1188 1189 while (depth >= 0) { 1190 if (depth == path->p_depth) { 1191 /* leaf */ 1192 if (path[depth].p_ext != 1193 EXT_LAST_EXTENT(path[depth].p_hdr)) 1194 return le32_to_cpu(path[depth].p_ext[1].ee_block); 1195 } else { 1196 /* index */ 1197 if (path[depth].p_idx != 1198 EXT_LAST_INDEX(path[depth].p_hdr)) 1199 return le32_to_cpu(path[depth].p_idx[1].ei_block); 1200 } 1201 depth--; 1202 } 1203 1204 return EXT_MAX_BLOCK; 1205} 1206 1207/* 1208 * ext4_ext_next_leaf_block: 1209 * returns first allocated block from next leaf or EXT_MAX_BLOCK 1210 */ 1211static ext4_lblk_t ext4_ext_next_leaf_block(struct inode *inode, 1212 struct ext4_ext_path *path) 1213{ 1214 int depth; 1215 1216 BUG_ON(path == NULL); 1217 depth = path->p_depth; 1218 1219 /* zero-tree has no leaf blocks at all */ 1220 if (depth == 0) 1221 return EXT_MAX_BLOCK; 1222 1223 /* go to index block */ 1224 depth--; 1225 1226 while (depth >= 0) { 1227 if (path[depth].p_idx != 1228 EXT_LAST_INDEX(path[depth].p_hdr)) 1229 return (ext4_lblk_t) 1230 le32_to_cpu(path[depth].p_idx[1].ei_block); 1231 depth--; 1232 } 1233 1234 return EXT_MAX_BLOCK; 1235} 1236 1237/* 1238 * ext4_ext_correct_indexes: 1239 * if leaf gets modified and modified extent is first in the leaf, 1240 * then we have to correct all indexes above. 1241 * TODO: do we need to correct tree in all cases? 1242 */ 1243static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode, 1244 struct ext4_ext_path *path) 1245{ 1246 struct ext4_extent_header *eh; 1247 int depth = ext_depth(inode); 1248 struct ext4_extent *ex; 1249 __le32 border; 1250 int k, err = 0; 1251 1252 eh = path[depth].p_hdr; 1253 ex = path[depth].p_ext; 1254 BUG_ON(ex == NULL); 1255 BUG_ON(eh == NULL); 1256 1257 if (depth == 0) { 1258 /* there is no tree at all */ 1259 return 0; 1260 } 1261 1262 if (ex != EXT_FIRST_EXTENT(eh)) { 1263 /* we correct tree if first leaf got modified only */ 1264 return 0; 1265 } 1266 1267 /* 1268 * TODO: we need correction if border is smaller than current one 1269 */ 1270 k = depth - 1; 1271 border = path[depth].p_ext->ee_block; 1272 err = ext4_ext_get_access(handle, inode, path + k); 1273 if (err) 1274 return err; 1275 path[k].p_idx->ei_block = border; 1276 err = ext4_ext_dirty(handle, inode, path + k); 1277 if (err) 1278 return err; 1279 1280 while (k--) { 1281 /* change all left-side indexes */ 1282 if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr)) 1283 break; 1284 err = ext4_ext_get_access(handle, inode, path + k); 1285 if (err) 1286 break; 1287 path[k].p_idx->ei_block = border; 1288 err = ext4_ext_dirty(handle, inode, path + k); 1289 if (err) 1290 break; 1291 } 1292 1293 return err; 1294} 1295 1296static int 1297ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1, 1298 struct ext4_extent *ex2) 1299{ 1300 unsigned short ext1_ee_len, ext2_ee_len, max_len; 1301 1302 /* 1303 * Make sure that either both extents are uninitialized, or 1304 * both are _not_. 1305 */ 1306 if (ext4_ext_is_uninitialized(ex1) ^ ext4_ext_is_uninitialized(ex2)) 1307 return 0; 1308 1309 if (ext4_ext_is_uninitialized(ex1)) 1310 max_len = EXT_UNINIT_MAX_LEN; 1311 else 1312 max_len = EXT_INIT_MAX_LEN; 1313 1314 ext1_ee_len = ext4_ext_get_actual_len(ex1); 1315 ext2_ee_len = ext4_ext_get_actual_len(ex2); 1316 1317 if (le32_to_cpu(ex1->ee_block) + ext1_ee_len != 1318 le32_to_cpu(ex2->ee_block)) 1319 return 0; 1320 1321 /* 1322 * To allow future support for preallocated extents to be added 1323 * as an RO_COMPAT feature, refuse to merge to extents if 1324 * this can result in the top bit of ee_len being set. 1325 */ 1326 if (ext1_ee_len + ext2_ee_len > max_len) 1327 return 0; 1328#ifdef AGGRESSIVE_TEST 1329 if (ext1_ee_len >= 4) 1330 return 0; 1331#endif 1332 1333 if (ext_pblock(ex1) + ext1_ee_len == ext_pblock(ex2)) 1334 return 1; 1335 return 0; 1336} 1337 1338/* 1339 * This function tries to merge the "ex" extent to the next extent in the tree. 1340 * It always tries to merge towards right. If you want to merge towards 1341 * left, pass "ex - 1" as argument instead of "ex". 1342 * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns 1343 * 1 if they got merged. 1344 */ 1345int ext4_ext_try_to_merge(struct inode *inode, 1346 struct ext4_ext_path *path, 1347 struct ext4_extent *ex) 1348{ 1349 struct ext4_extent_header *eh; 1350 unsigned int depth, len; 1351 int merge_done = 0; 1352 int uninitialized = 0; 1353 1354 depth = ext_depth(inode); 1355 BUG_ON(path[depth].p_hdr == NULL); 1356 eh = path[depth].p_hdr; 1357 1358 while (ex < EXT_LAST_EXTENT(eh)) { 1359 if (!ext4_can_extents_be_merged(inode, ex, ex + 1)) 1360 break; 1361 /* merge with next extent! */ 1362 if (ext4_ext_is_uninitialized(ex)) 1363 uninitialized = 1; 1364 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex) 1365 + ext4_ext_get_actual_len(ex + 1)); 1366 if (uninitialized) 1367 ext4_ext_mark_uninitialized(ex); 1368 1369 if (ex + 1 < EXT_LAST_EXTENT(eh)) { 1370 len = (EXT_LAST_EXTENT(eh) - ex - 1) 1371 * sizeof(struct ext4_extent); 1372 memmove(ex + 1, ex + 2, len); 1373 } 1374 le16_add_cpu(&eh->eh_entries, -1); 1375 merge_done = 1; 1376 WARN_ON(eh->eh_entries == 0); 1377 if (!eh->eh_entries) 1378 ext4_error(inode->i_sb, "ext4_ext_try_to_merge", 1379 "inode#%lu, eh->eh_entries = 0!", inode->i_ino); 1380 } 1381 1382 return merge_done; 1383} 1384 1385/* 1386 * check if a portion of the "newext" extent overlaps with an 1387 * existing extent. 1388 * 1389 * If there is an overlap discovered, it updates the length of the newext 1390 * such that there will be no overlap, and then returns 1. 1391 * If there is no overlap found, it returns 0. 1392 */ 1393unsigned int ext4_ext_check_overlap(struct inode *inode, 1394 struct ext4_extent *newext, 1395 struct ext4_ext_path *path) 1396{ 1397 ext4_lblk_t b1, b2; 1398 unsigned int depth, len1; 1399 unsigned int ret = 0; 1400 1401 b1 = le32_to_cpu(newext->ee_block); 1402 len1 = ext4_ext_get_actual_len(newext); 1403 depth = ext_depth(inode); 1404 if (!path[depth].p_ext) 1405 goto out; 1406 b2 = le32_to_cpu(path[depth].p_ext->ee_block); 1407 1408 /* 1409 * get the next allocated block if the extent in the path 1410 * is before the requested block(s) 1411 */ 1412 if (b2 < b1) { 1413 b2 = ext4_ext_next_allocated_block(path); 1414 if (b2 == EXT_MAX_BLOCK) 1415 goto out; 1416 } 1417 1418 /* check for wrap through zero on extent logical start block*/ 1419 if (b1 + len1 < b1) { 1420 len1 = EXT_MAX_BLOCK - b1; 1421 newext->ee_len = cpu_to_le16(len1); 1422 ret = 1; 1423 } 1424 1425 /* check for overlap */ 1426 if (b1 + len1 > b2) { 1427 newext->ee_len = cpu_to_le16(b2 - b1); 1428 ret = 1; 1429 } 1430out: 1431 return ret; 1432} 1433 1434/* 1435 * ext4_ext_insert_extent: 1436 * tries to merge requsted extent into the existing extent or 1437 * inserts requested extent as new one into the tree, 1438 * creating new leaf in the no-space case. 1439 */ 1440int ext4_ext_insert_extent(handle_t *handle, struct inode *inode, 1441 struct ext4_ext_path *path, 1442 struct ext4_extent *newext) 1443{ 1444 struct ext4_extent_header * eh; 1445 struct ext4_extent *ex, *fex; 1446 struct ext4_extent *nearex; /* nearest extent */ 1447 struct ext4_ext_path *npath = NULL; 1448 int depth, len, err; 1449 ext4_lblk_t next; 1450 unsigned uninitialized = 0; 1451 1452 BUG_ON(ext4_ext_get_actual_len(newext) == 0); 1453 depth = ext_depth(inode); 1454 ex = path[depth].p_ext; 1455 BUG_ON(path[depth].p_hdr == NULL); 1456 1457 /* try to insert block into found extent and return */ 1458 if (ex && ext4_can_extents_be_merged(inode, ex, newext)) { 1459 ext_debug("append %d block to %d:%d (from %llu)\n", 1460 ext4_ext_get_actual_len(newext), 1461 le32_to_cpu(ex->ee_block), 1462 ext4_ext_get_actual_len(ex), ext_pblock(ex)); 1463 err = ext4_ext_get_access(handle, inode, path + depth); 1464 if (err) 1465 return err; 1466 1467 /* 1468 * ext4_can_extents_be_merged should have checked that either 1469 * both extents are uninitialized, or both aren't. Thus we 1470 * need to check only one of them here. 1471 */ 1472 if (ext4_ext_is_uninitialized(ex)) 1473 uninitialized = 1; 1474 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex) 1475 + ext4_ext_get_actual_len(newext)); 1476 if (uninitialized) 1477 ext4_ext_mark_uninitialized(ex); 1478 eh = path[depth].p_hdr; 1479 nearex = ex; 1480 goto merge; 1481 } 1482 1483repeat: 1484 depth = ext_depth(inode); 1485 eh = path[depth].p_hdr; 1486 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) 1487 goto has_space; 1488 1489 /* probably next leaf has space for us? */ 1490 fex = EXT_LAST_EXTENT(eh); 1491 next = ext4_ext_next_leaf_block(inode, path); 1492 if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block) 1493 && next != EXT_MAX_BLOCK) { 1494 ext_debug("next leaf block - %d\n", next); 1495 BUG_ON(npath != NULL); 1496 npath = ext4_ext_find_extent(inode, next, NULL); 1497 if (IS_ERR(npath)) 1498 return PTR_ERR(npath); 1499 BUG_ON(npath->p_depth != path->p_depth); 1500 eh = npath[depth].p_hdr; 1501 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) { 1502 ext_debug("next leaf isnt full(%d)\n", 1503 le16_to_cpu(eh->eh_entries)); 1504 path = npath; 1505 goto repeat; 1506 } 1507 ext_debug("next leaf has no free space(%d,%d)\n", 1508 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max)); 1509 } 1510 1511 /* 1512 * There is no free space in the found leaf. 1513 * We're gonna add a new leaf in the tree. 1514 */ 1515 err = ext4_ext_create_new_leaf(handle, inode, path, newext); 1516 if (err) 1517 goto cleanup; 1518 depth = ext_depth(inode); 1519 eh = path[depth].p_hdr; 1520 1521has_space: 1522 nearex = path[depth].p_ext; 1523 1524 err = ext4_ext_get_access(handle, inode, path + depth); 1525 if (err) 1526 goto cleanup; 1527 1528 if (!nearex) { 1529 /* there is no extent in this leaf, create first one */ 1530 ext_debug("first extent in the leaf: %d:%llu:%d\n", 1531 le32_to_cpu(newext->ee_block), 1532 ext_pblock(newext), 1533 ext4_ext_get_actual_len(newext)); 1534 path[depth].p_ext = EXT_FIRST_EXTENT(eh); 1535 } else if (le32_to_cpu(newext->ee_block) 1536 > le32_to_cpu(nearex->ee_block)) { 1537/* BUG_ON(newext->ee_block == nearex->ee_block); */ 1538 if (nearex != EXT_LAST_EXTENT(eh)) { 1539 len = EXT_MAX_EXTENT(eh) - nearex; 1540 len = (len - 1) * sizeof(struct ext4_extent); 1541 len = len < 0 ? 0 : len; 1542 ext_debug("insert %d:%llu:%d after: nearest 0x%p, " 1543 "move %d from 0x%p to 0x%p\n", 1544 le32_to_cpu(newext->ee_block), 1545 ext_pblock(newext), 1546 ext4_ext_get_actual_len(newext), 1547 nearex, len, nearex + 1, nearex + 2); 1548 memmove(nearex + 2, nearex + 1, len); 1549 } 1550 path[depth].p_ext = nearex + 1; 1551 } else { 1552 BUG_ON(newext->ee_block == nearex->ee_block); 1553 len = (EXT_MAX_EXTENT(eh) - nearex) * sizeof(struct ext4_extent); 1554 len = len < 0 ? 0 : len; 1555 ext_debug("insert %d:%llu:%d before: nearest 0x%p, " 1556 "move %d from 0x%p to 0x%p\n", 1557 le32_to_cpu(newext->ee_block), 1558 ext_pblock(newext), 1559 ext4_ext_get_actual_len(newext), 1560 nearex, len, nearex + 1, nearex + 2); 1561 memmove(nearex + 1, nearex, len); 1562 path[depth].p_ext = nearex; 1563 } 1564 1565 le16_add_cpu(&eh->eh_entries, 1); 1566 nearex = path[depth].p_ext; 1567 nearex->ee_block = newext->ee_block; 1568 ext4_ext_store_pblock(nearex, ext_pblock(newext)); 1569 nearex->ee_len = newext->ee_len; 1570 1571merge: 1572 /* try to merge extents to the right */ 1573 ext4_ext_try_to_merge(inode, path, nearex); 1574 1575 /* try to merge extents to the left */ 1576 1577 /* time to correct all indexes above */ 1578 err = ext4_ext_correct_indexes(handle, inode, path); 1579 if (err) 1580 goto cleanup; 1581 1582 err = ext4_ext_dirty(handle, inode, path + depth); 1583 1584cleanup: 1585 if (npath) { 1586 ext4_ext_drop_refs(npath); 1587 kfree(npath); 1588 } 1589 ext4_ext_tree_changed(inode); 1590 ext4_ext_invalidate_cache(inode); 1591 return err; 1592} 1593 1594static void 1595ext4_ext_put_in_cache(struct inode *inode, ext4_lblk_t block, 1596 __u32 len, ext4_fsblk_t start, int type) 1597{ 1598 struct ext4_ext_cache *cex; 1599 BUG_ON(len == 0); 1600 cex = &EXT4_I(inode)->i_cached_extent; 1601 cex->ec_type = type; 1602 cex->ec_block = block; 1603 cex->ec_len = len; 1604 cex->ec_start = start; 1605} 1606 1607/* 1608 * ext4_ext_put_gap_in_cache: 1609 * calculate boundaries of the gap that the requested block fits into 1610 * and cache this gap 1611 */ 1612static void 1613ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path, 1614 ext4_lblk_t block) 1615{ 1616 int depth = ext_depth(inode); 1617 unsigned long len; 1618 ext4_lblk_t lblock; 1619 struct ext4_extent *ex; 1620 1621 ex = path[depth].p_ext; 1622 if (ex == NULL) { 1623 /* there is no extent yet, so gap is [0;-] */ 1624 lblock = 0; 1625 len = EXT_MAX_BLOCK; 1626 ext_debug("cache gap(whole file):"); 1627 } else if (block < le32_to_cpu(ex->ee_block)) { 1628 lblock = block; 1629 len = le32_to_cpu(ex->ee_block) - block; 1630 ext_debug("cache gap(before): %u [%u:%u]", 1631 block, 1632 le32_to_cpu(ex->ee_block), 1633 ext4_ext_get_actual_len(ex)); 1634 } else if (block >= le32_to_cpu(ex->ee_block) 1635 + ext4_ext_get_actual_len(ex)) { 1636 ext4_lblk_t next; 1637 lblock = le32_to_cpu(ex->ee_block) 1638 + ext4_ext_get_actual_len(ex); 1639 1640 next = ext4_ext_next_allocated_block(path); 1641 ext_debug("cache gap(after): [%u:%u] %u", 1642 le32_to_cpu(ex->ee_block), 1643 ext4_ext_get_actual_len(ex), 1644 block); 1645 BUG_ON(next == lblock); 1646 len = next - lblock; 1647 } else { 1648 lblock = len = 0; 1649 BUG(); 1650 } 1651 1652 ext_debug(" -> %u:%lu\n", lblock, len); 1653 ext4_ext_put_in_cache(inode, lblock, len, 0, EXT4_EXT_CACHE_GAP); 1654} 1655 1656static int 1657ext4_ext_in_cache(struct inode *inode, ext4_lblk_t block, 1658 struct ext4_extent *ex) 1659{ 1660 struct ext4_ext_cache *cex; 1661 1662 cex = &EXT4_I(inode)->i_cached_extent; 1663 1664 /* has cache valid data? */ 1665 if (cex->ec_type == EXT4_EXT_CACHE_NO) 1666 return EXT4_EXT_CACHE_NO; 1667 1668 BUG_ON(cex->ec_type != EXT4_EXT_CACHE_GAP && 1669 cex->ec_type != EXT4_EXT_CACHE_EXTENT); 1670 if (block >= cex->ec_block && block < cex->ec_block + cex->ec_len) { 1671 ex->ee_block = cpu_to_le32(cex->ec_block); 1672 ext4_ext_store_pblock(ex, cex->ec_start); 1673 ex->ee_len = cpu_to_le16(cex->ec_len); 1674 ext_debug("%u cached by %u:%u:%llu\n", 1675 block, 1676 cex->ec_block, cex->ec_len, cex->ec_start); 1677 return cex->ec_type; 1678 } 1679 1680 /* not in cache */ 1681 return EXT4_EXT_CACHE_NO; 1682} 1683 1684/* 1685 * ext4_ext_rm_idx: 1686 * removes index from the index block. 1687 * It's used in truncate case only, thus all requests are for 1688 * last index in the block only. 1689 */ 1690static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode, 1691 struct ext4_ext_path *path) 1692{ 1693 struct buffer_head *bh; 1694 int err; 1695 ext4_fsblk_t leaf; 1696 1697 /* free index block */ 1698 path--; 1699 leaf = idx_pblock(path->p_idx); 1700 BUG_ON(path->p_hdr->eh_entries == 0); 1701 err = ext4_ext_get_access(handle, inode, path); 1702 if (err) 1703 return err; 1704 le16_add_cpu(&path->p_hdr->eh_entries, -1); 1705 err = ext4_ext_dirty(handle, inode, path); 1706 if (err) 1707 return err; 1708 ext_debug("index is empty, remove it, free block %llu\n", leaf); 1709 bh = sb_find_get_block(inode->i_sb, leaf); 1710 ext4_forget(handle, 1, inode, bh, leaf); 1711 ext4_free_blocks(handle, inode, leaf, 1, 1); 1712 return err; 1713} 1714 1715/* 1716 * ext4_ext_calc_credits_for_insert: 1717 * This routine returns max. credits that the extent tree can consume. 1718 * It should be OK for low-performance paths like ->writepage() 1719 * To allow many writing processes to fit into a single transaction, 1720 * the caller should calculate credits under i_data_sem and 1721 * pass the actual path. 1722 */ 1723int ext4_ext_calc_credits_for_insert(struct inode *inode, 1724 struct ext4_ext_path *path) 1725{ 1726 int depth, needed; 1727 1728 if (path) { 1729 /* probably there is space in leaf? */ 1730 depth = ext_depth(inode); 1731 if (le16_to_cpu(path[depth].p_hdr->eh_entries) 1732 < le16_to_cpu(path[depth].p_hdr->eh_max)) 1733 return 1; 1734 } 1735 1736 /* 1737 * given 32-bit logical block (4294967296 blocks), max. tree 1738 * can be 4 levels in depth -- 4 * 340^4 == 53453440000. 1739 * Let's also add one more level for imbalance. 1740 */ 1741 depth = 5; 1742 1743 /* allocation of new data block(s) */ 1744 needed = 2; 1745 1746 /* 1747 * tree can be full, so it would need to grow in depth: 1748 * we need one credit to modify old root, credits for 1749 * new root will be added in split accounting 1750 */ 1751 needed += 1; 1752 1753 /* 1754 * Index split can happen, we would need: 1755 * allocate intermediate indexes (bitmap + group) 1756 * + change two blocks at each level, but root (already included) 1757 */ 1758 needed += (depth * 2) + (depth * 2); 1759 1760 /* any allocation modifies superblock */ 1761 needed += 1; 1762 1763 return needed; 1764} 1765 1766static int ext4_remove_blocks(handle_t *handle, struct inode *inode, 1767 struct ext4_extent *ex, 1768 ext4_lblk_t from, ext4_lblk_t to) 1769{ 1770 struct buffer_head *bh; 1771 unsigned short ee_len = ext4_ext_get_actual_len(ex); 1772 int i, metadata = 0; 1773 1774 if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) 1775 metadata = 1; 1776#ifdef EXTENTS_STATS 1777 { 1778 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 1779 spin_lock(&sbi->s_ext_stats_lock); 1780 sbi->s_ext_blocks += ee_len; 1781 sbi->s_ext_extents++; 1782 if (ee_len < sbi->s_ext_min) 1783 sbi->s_ext_min = ee_len; 1784 if (ee_len > sbi->s_ext_max) 1785 sbi->s_ext_max = ee_len; 1786 if (ext_depth(inode) > sbi->s_depth_max) 1787 sbi->s_depth_max = ext_depth(inode); 1788 spin_unlock(&sbi->s_ext_stats_lock); 1789 } 1790#endif 1791 if (from >= le32_to_cpu(ex->ee_block) 1792 && to == le32_to_cpu(ex->ee_block) + ee_len - 1) { 1793 /* tail removal */ 1794 ext4_lblk_t num; 1795 ext4_fsblk_t start; 1796 1797 num = le32_to_cpu(ex->ee_block) + ee_len - from; 1798 start = ext_pblock(ex) + ee_len - num; 1799 ext_debug("free last %u blocks starting %llu\n", num, start); 1800 for (i = 0; i < num; i++) { 1801 bh = sb_find_get_block(inode->i_sb, start + i); 1802 ext4_forget(handle, 0, inode, bh, start + i); 1803 } 1804 ext4_free_blocks(handle, inode, start, num, metadata); 1805 } else if (from == le32_to_cpu(ex->ee_block) 1806 && to <= le32_to_cpu(ex->ee_block) + ee_len - 1) { 1807 printk(KERN_INFO "strange request: removal %u-%u from %u:%u\n", 1808 from, to, le32_to_cpu(ex->ee_block), ee_len); 1809 } else { 1810 printk(KERN_INFO "strange request: removal(2) " 1811 "%u-%u from %u:%u\n", 1812 from, to, le32_to_cpu(ex->ee_block), ee_len); 1813 } 1814 return 0; 1815} 1816 1817static int 1818ext4_ext_rm_leaf(handle_t *handle, struct inode *inode, 1819 struct ext4_ext_path *path, ext4_lblk_t start) 1820{ 1821 int err = 0, correct_index = 0; 1822 int depth = ext_depth(inode), credits; 1823 struct ext4_extent_header *eh; 1824 ext4_lblk_t a, b, block; 1825 unsigned num; 1826 ext4_lblk_t ex_ee_block; 1827 unsigned short ex_ee_len; 1828 unsigned uninitialized = 0; 1829 struct ext4_extent *ex; 1830 1831 /* the header must be checked already in ext4_ext_remove_space() */ 1832 ext_debug("truncate since %u in leaf\n", start); 1833 if (!path[depth].p_hdr) 1834 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh); 1835 eh = path[depth].p_hdr; 1836 BUG_ON(eh == NULL); 1837 1838 /* find where to start removing */ 1839 ex = EXT_LAST_EXTENT(eh); 1840 1841 ex_ee_block = le32_to_cpu(ex->ee_block); 1842 if (ext4_ext_is_uninitialized(ex)) 1843 uninitialized = 1; 1844 ex_ee_len = ext4_ext_get_actual_len(ex); 1845 1846 while (ex >= EXT_FIRST_EXTENT(eh) && 1847 ex_ee_block + ex_ee_len > start) { 1848 ext_debug("remove ext %lu:%u\n", ex_ee_block, ex_ee_len); 1849 path[depth].p_ext = ex; 1850 1851 a = ex_ee_block > start ? ex_ee_block : start; 1852 b = ex_ee_block + ex_ee_len - 1 < EXT_MAX_BLOCK ? 1853 ex_ee_block + ex_ee_len - 1 : EXT_MAX_BLOCK; 1854 1855 ext_debug(" border %u:%u\n", a, b); 1856 1857 if (a != ex_ee_block && b != ex_ee_block + ex_ee_len - 1) { 1858 block = 0; 1859 num = 0; 1860 BUG(); 1861 } else if (a != ex_ee_block) { 1862 /* remove tail of the extent */ 1863 block = ex_ee_block; 1864 num = a - block; 1865 } else if (b != ex_ee_block + ex_ee_len - 1) { 1866 /* remove head of the extent */ 1867 block = a; 1868 num = b - a; 1869 /* there is no "make a hole" API yet */ 1870 BUG(); 1871 } else { 1872 /* remove whole extent: excellent! */ 1873 block = ex_ee_block; 1874 num = 0; 1875 BUG_ON(a != ex_ee_block); 1876 BUG_ON(b != ex_ee_block + ex_ee_len - 1); 1877 } 1878 1879 /* at present, extent can't cross block group: */ 1880 /* leaf + bitmap + group desc + sb + inode */ 1881 credits = 5; 1882 if (ex == EXT_FIRST_EXTENT(eh)) { 1883 correct_index = 1; 1884 credits += (ext_depth(inode)) + 1; 1885 } 1886#ifdef CONFIG_QUOTA 1887 credits += 2 * EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb); 1888#endif 1889 1890 err = ext4_ext_journal_restart(handle, credits); 1891 if (err) 1892 goto out; 1893 1894 err = ext4_ext_get_access(handle, inode, path + depth); 1895 if (err) 1896 goto out; 1897 1898 err = ext4_remove_blocks(handle, inode, ex, a, b); 1899 if (err) 1900 goto out; 1901 1902 if (num == 0) { 1903 /* this extent is removed; mark slot entirely unused */ 1904 ext4_ext_store_pblock(ex, 0); 1905 le16_add_cpu(&eh->eh_entries, -1); 1906 } 1907 1908 ex->ee_block = cpu_to_le32(block); 1909 ex->ee_len = cpu_to_le16(num); 1910 /* 1911 * Do not mark uninitialized if all the blocks in the 1912 * extent have been removed. 1913 */ 1914 if (uninitialized && num) 1915 ext4_ext_mark_uninitialized(ex); 1916 1917 err = ext4_ext_dirty(handle, inode, path + depth); 1918 if (err) 1919 goto out; 1920 1921 ext_debug("new extent: %u:%u:%llu\n", block, num, 1922 ext_pblock(ex)); 1923 ex--; 1924 ex_ee_block = le32_to_cpu(ex->ee_block); 1925 ex_ee_len = ext4_ext_get_actual_len(ex); 1926 } 1927 1928 if (correct_index && eh->eh_entries) 1929 err = ext4_ext_correct_indexes(handle, inode, path); 1930 1931 /* if this leaf is free, then we should 1932 * remove it from index block above */ 1933 if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL) 1934 err = ext4_ext_rm_idx(handle, inode, path + depth); 1935 1936out: 1937 return err; 1938} 1939 1940/* 1941 * ext4_ext_more_to_rm: 1942 * returns 1 if current index has to be freed (even partial) 1943 */ 1944static int 1945ext4_ext_more_to_rm(struct ext4_ext_path *path) 1946{ 1947 BUG_ON(path->p_idx == NULL); 1948 1949 if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr)) 1950 return 0; 1951 1952 /* 1953 * if truncate on deeper level happened, it wasn't partial, 1954 * so we have to consider current index for truncation 1955 */ 1956 if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block) 1957 return 0; 1958 return 1; 1959} 1960 1961static int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start) 1962{ 1963 struct super_block *sb = inode->i_sb; 1964 int depth = ext_depth(inode); 1965 struct ext4_ext_path *path; 1966 handle_t *handle; 1967 int i = 0, err = 0; 1968 1969 ext_debug("truncate since %u\n", start); 1970 1971 /* probably first extent we're gonna free will be last in block */ 1972 handle = ext4_journal_start(inode, depth + 1); 1973 if (IS_ERR(handle)) 1974 return PTR_ERR(handle); 1975 1976 ext4_ext_invalidate_cache(inode); 1977 1978 /* 1979 * We start scanning from right side, freeing all the blocks 1980 * after i_size and walking into the tree depth-wise. 1981 */ 1982 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1), GFP_NOFS); 1983 if (path == NULL) { 1984 ext4_journal_stop(handle); 1985 return -ENOMEM; 1986 } 1987 path[0].p_hdr = ext_inode_hdr(inode); 1988 if (ext4_ext_check_header(inode, path[0].p_hdr, depth)) { 1989 err = -EIO; 1990 goto out; 1991 } 1992 path[0].p_depth = depth; 1993 1994 while (i >= 0 && err == 0) { 1995 if (i == depth) { 1996 /* this is leaf block */ 1997 err = ext4_ext_rm_leaf(handle, inode, path, start); 1998 /* root level has p_bh == NULL, brelse() eats this */ 1999 brelse(path[i].p_bh); 2000 path[i].p_bh = NULL; 2001 i--; 2002 continue; 2003 } 2004 2005 /* this is index block */ 2006 if (!path[i].p_hdr) { 2007 ext_debug("initialize header\n"); 2008 path[i].p_hdr = ext_block_hdr(path[i].p_bh); 2009 } 2010 2011 if (!path[i].p_idx) { 2012 /* this level hasn't been touched yet */ 2013 path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr); 2014 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1; 2015 ext_debug("init index ptr: hdr 0x%p, num %d\n", 2016 path[i].p_hdr, 2017 le16_to_cpu(path[i].p_hdr->eh_entries)); 2018 } else { 2019 /* we were already here, see at next index */ 2020 path[i].p_idx--; 2021 } 2022 2023 ext_debug("level %d - index, first 0x%p, cur 0x%p\n", 2024 i, EXT_FIRST_INDEX(path[i].p_hdr), 2025 path[i].p_idx); 2026 if (ext4_ext_more_to_rm(path + i)) { 2027 struct buffer_head *bh; 2028 /* go to the next level */ 2029 ext_debug("move to level %d (block %llu)\n", 2030 i + 1, idx_pblock(path[i].p_idx)); 2031 memset(path + i + 1, 0, sizeof(*path)); 2032 bh = sb_bread(sb, idx_pblock(path[i].p_idx)); 2033 if (!bh) { 2034 /* should we reset i_size? */ 2035 err = -EIO; 2036 break; 2037 } 2038 if (WARN_ON(i + 1 > depth)) { 2039 err = -EIO; 2040 break; 2041 } 2042 if (ext4_ext_check_header(inode, ext_block_hdr(bh), 2043 depth - i - 1)) { 2044 err = -EIO; 2045 break; 2046 } 2047 path[i + 1].p_bh = bh; 2048 2049 /* save actual number of indexes since this 2050 * number is changed at the next iteration */ 2051 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries); 2052 i++; 2053 } else { 2054 /* we finished processing this index, go up */ 2055 if (path[i].p_hdr->eh_entries == 0 && i > 0) { 2056 /* index is empty, remove it; 2057 * handle must be already prepared by the 2058 * truncatei_leaf() */ 2059 err = ext4_ext_rm_idx(handle, inode, path + i); 2060 } 2061 /* root level has p_bh == NULL, brelse() eats this */ 2062 brelse(path[i].p_bh); 2063 path[i].p_bh = NULL; 2064 i--; 2065 ext_debug("return to level %d\n", i); 2066 } 2067 } 2068 2069 /* TODO: flexible tree reduction should be here */ 2070 if (path->p_hdr->eh_entries == 0) { 2071 /* 2072 * truncate to zero freed all the tree, 2073 * so we need to correct eh_depth 2074 */ 2075 err = ext4_ext_get_access(handle, inode, path); 2076 if (err == 0) { 2077 ext_inode_hdr(inode)->eh_depth = 0; 2078 ext_inode_hdr(inode)->eh_max = 2079 cpu_to_le16(ext4_ext_space_root(inode)); 2080 err = ext4_ext_dirty(handle, inode, path); 2081 } 2082 } 2083out: 2084 ext4_ext_tree_changed(inode); 2085 ext4_ext_drop_refs(path); 2086 kfree(path); 2087 ext4_journal_stop(handle); 2088 2089 return err; 2090} 2091 2092/* 2093 * called at mount time 2094 */ 2095void ext4_ext_init(struct super_block *sb) 2096{ 2097 /* 2098 * possible initialization would be here 2099 */ 2100 2101 if (test_opt(sb, EXTENTS)) { 2102 printk("EXT4-fs: file extents enabled"); 2103#ifdef AGGRESSIVE_TEST 2104 printk(", aggressive tests"); 2105#endif 2106#ifdef CHECK_BINSEARCH 2107 printk(", check binsearch"); 2108#endif 2109#ifdef EXTENTS_STATS 2110 printk(", stats"); 2111#endif 2112 printk("\n"); 2113#ifdef EXTENTS_STATS 2114 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock); 2115 EXT4_SB(sb)->s_ext_min = 1 << 30; 2116 EXT4_SB(sb)->s_ext_max = 0; 2117#endif 2118 } 2119} 2120 2121/* 2122 * called at umount time 2123 */ 2124void ext4_ext_release(struct super_block *sb) 2125{ 2126 if (!test_opt(sb, EXTENTS)) 2127 return; 2128 2129#ifdef EXTENTS_STATS 2130 if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) { 2131 struct ext4_sb_info *sbi = EXT4_SB(sb); 2132 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n", 2133 sbi->s_ext_blocks, sbi->s_ext_extents, 2134 sbi->s_ext_blocks / sbi->s_ext_extents); 2135 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n", 2136 sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max); 2137 } 2138#endif 2139} 2140 2141static void bi_complete(struct bio *bio, int error) 2142{ 2143 complete((struct completion *)bio->bi_private); 2144} 2145 2146/* FIXME!! we need to try to merge to left or right after zero-out */ 2147static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex) 2148{ 2149 int ret = -EIO; 2150 struct bio *bio; 2151 int blkbits, blocksize; 2152 sector_t ee_pblock; 2153 struct completion event; 2154 unsigned int ee_len, len, done, offset; 2155 2156 2157 blkbits = inode->i_blkbits; 2158 blocksize = inode->i_sb->s_blocksize; 2159 ee_len = ext4_ext_get_actual_len(ex); 2160 ee_pblock = ext_pblock(ex); 2161 2162 /* convert ee_pblock to 512 byte sectors */ 2163 ee_pblock = ee_pblock << (blkbits - 9); 2164 2165 while (ee_len > 0) { 2166 2167 if (ee_len > BIO_MAX_PAGES) 2168 len = BIO_MAX_PAGES; 2169 else 2170 len = ee_len; 2171 2172 bio = bio_alloc(GFP_NOIO, len); 2173 if (!bio) 2174 return -ENOMEM; 2175 bio->bi_sector = ee_pblock; 2176 bio->bi_bdev = inode->i_sb->s_bdev; 2177 2178 done = 0; 2179 offset = 0; 2180 while (done < len) { 2181 ret = bio_add_page(bio, ZERO_PAGE(0), 2182 blocksize, offset); 2183 if (ret != blocksize) { 2184 /* 2185 * We can't add any more pages because of 2186 * hardware limitations. Start a new bio. 2187 */ 2188 break; 2189 } 2190 done++; 2191 offset += blocksize; 2192 if (offset >= PAGE_CACHE_SIZE) 2193 offset = 0; 2194 } 2195 2196 init_completion(&event); 2197 bio->bi_private = &event; 2198 bio->bi_end_io = bi_complete; 2199 submit_bio(WRITE, bio); 2200 wait_for_completion(&event); 2201 2202 if (test_bit(BIO_UPTODATE, &bio->bi_flags)) 2203 ret = 0; 2204 else { 2205 ret = -EIO; 2206 break; 2207 } 2208 bio_put(bio); 2209 ee_len -= done; 2210 ee_pblock += done << (blkbits - 9); 2211 } 2212 return ret; 2213} 2214 2215#define EXT4_EXT_ZERO_LEN 7 2216 2217/* 2218 * This function is called by ext4_ext_get_blocks() if someone tries to write 2219 * to an uninitialized extent. It may result in splitting the uninitialized 2220 * extent into multiple extents (upto three - one initialized and two 2221 * uninitialized). 2222 * There are three possibilities: 2223 * a> There is no split required: Entire extent should be initialized 2224 * b> Splits in two extents: Write is happening at either end of the extent 2225 * c> Splits in three extents: Somone is writing in middle of the extent 2226 */ 2227static int ext4_ext_convert_to_initialized(handle_t *handle, 2228 struct inode *inode, 2229 struct ext4_ext_path *path, 2230 ext4_lblk_t iblock, 2231 unsigned long max_blocks) 2232{ 2233 struct ext4_extent *ex, newex, orig_ex; 2234 struct ext4_extent *ex1 = NULL; 2235 struct ext4_extent *ex2 = NULL; 2236 struct ext4_extent *ex3 = NULL; 2237 struct ext4_extent_header *eh; 2238 ext4_lblk_t ee_block; 2239 unsigned int allocated, ee_len, depth; 2240 ext4_fsblk_t newblock; 2241 int err = 0; 2242 int ret = 0; 2243 2244 depth = ext_depth(inode); 2245 eh = path[depth].p_hdr; 2246 ex = path[depth].p_ext; 2247 ee_block = le32_to_cpu(ex->ee_block); 2248 ee_len = ext4_ext_get_actual_len(ex); 2249 allocated = ee_len - (iblock - ee_block); 2250 newblock = iblock - ee_block + ext_pblock(ex); 2251 ex2 = ex; 2252 orig_ex.ee_block = ex->ee_block; 2253 orig_ex.ee_len = cpu_to_le16(ee_len); 2254 ext4_ext_store_pblock(&orig_ex, ext_pblock(ex)); 2255 2256 err = ext4_ext_get_access(handle, inode, path + depth); 2257 if (err) 2258 goto out; 2259 /* If extent has less than 2*EXT4_EXT_ZERO_LEN zerout directly */ 2260 if (ee_len <= 2*EXT4_EXT_ZERO_LEN) { 2261 err = ext4_ext_zeroout(inode, &orig_ex); 2262 if (err) 2263 goto fix_extent_len; 2264 /* update the extent length and mark as initialized */ 2265 ex->ee_block = orig_ex.ee_block; 2266 ex->ee_len = orig_ex.ee_len; 2267 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2268 ext4_ext_dirty(handle, inode, path + depth); 2269 /* zeroed the full extent */ 2270 return allocated; 2271 } 2272 2273 /* ex1: ee_block to iblock - 1 : uninitialized */ 2274 if (iblock > ee_block) { 2275 ex1 = ex; 2276 ex1->ee_len = cpu_to_le16(iblock - ee_block); 2277 ext4_ext_mark_uninitialized(ex1); 2278 ex2 = &newex; 2279 } 2280 /* 2281 * for sanity, update the length of the ex2 extent before 2282 * we insert ex3, if ex1 is NULL. This is to avoid temporary 2283 * overlap of blocks. 2284 */ 2285 if (!ex1 && allocated > max_blocks) 2286 ex2->ee_len = cpu_to_le16(max_blocks); 2287 /* ex3: to ee_block + ee_len : uninitialised */ 2288 if (allocated > max_blocks) { 2289 unsigned int newdepth; 2290 /* If extent has less than EXT4_EXT_ZERO_LEN zerout directly */ 2291 if (allocated <= EXT4_EXT_ZERO_LEN) { 2292 /* Mark first half uninitialized. 2293 * Mark second half initialized and zero out the 2294 * initialized extent 2295 */ 2296 ex->ee_block = orig_ex.ee_block; 2297 ex->ee_len = cpu_to_le16(ee_len - allocated); 2298 ext4_ext_mark_uninitialized(ex); 2299 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2300 ext4_ext_dirty(handle, inode, path + depth); 2301 2302 ex3 = &newex; 2303 ex3->ee_block = cpu_to_le32(iblock); 2304 ext4_ext_store_pblock(ex3, newblock); 2305 ex3->ee_len = cpu_to_le16(allocated); 2306 err = ext4_ext_insert_extent(handle, inode, path, ex3); 2307 if (err == -ENOSPC) { 2308 err = ext4_ext_zeroout(inode, &orig_ex); 2309 if (err) 2310 goto fix_extent_len; 2311 ex->ee_block = orig_ex.ee_block; 2312 ex->ee_len = orig_ex.ee_len; 2313 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2314 ext4_ext_dirty(handle, inode, path + depth); 2315 /* zeroed the full extent */ 2316 return allocated; 2317 2318 } else if (err) 2319 goto fix_extent_len; 2320 2321 /* 2322 * We need to zero out the second half because 2323 * an fallocate request can update file size and 2324 * converting the second half to initialized extent 2325 * implies that we can leak some junk data to user 2326 * space. 2327 */ 2328 err = ext4_ext_zeroout(inode, ex3); 2329 if (err) { 2330 /* 2331 * We should actually mark the 2332 * second half as uninit and return error 2333 * Insert would have changed the extent 2334 */ 2335 depth = ext_depth(inode); 2336 ext4_ext_drop_refs(path); 2337 path = ext4_ext_find_extent(inode, 2338 iblock, path); 2339 if (IS_ERR(path)) { 2340 err = PTR_ERR(path); 2341 return err; 2342 } 2343 ex = path[depth].p_ext; 2344 err = ext4_ext_get_access(handle, inode, 2345 path + depth); 2346 if (err) 2347 return err; 2348 ext4_ext_mark_uninitialized(ex); 2349 ext4_ext_dirty(handle, inode, path + depth); 2350 return err; 2351 } 2352 2353 /* zeroed the second half */ 2354 return allocated; 2355 } 2356 ex3 = &newex; 2357 ex3->ee_block = cpu_to_le32(iblock + max_blocks); 2358 ext4_ext_store_pblock(ex3, newblock + max_blocks); 2359 ex3->ee_len = cpu_to_le16(allocated - max_blocks); 2360 ext4_ext_mark_uninitialized(ex3); 2361 err = ext4_ext_insert_extent(handle, inode, path, ex3); 2362 if (err == -ENOSPC) { 2363 err = ext4_ext_zeroout(inode, &orig_ex); 2364 if (err) 2365 goto fix_extent_len; 2366 /* update the extent length and mark as initialized */ 2367 ex->ee_block = orig_ex.ee_block; 2368 ex->ee_len = orig_ex.ee_len; 2369 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2370 ext4_ext_dirty(handle, inode, path + depth); 2371 /* zeroed the full extent */ 2372 return allocated; 2373 2374 } else if (err) 2375 goto fix_extent_len; 2376 /* 2377 * The depth, and hence eh & ex might change 2378 * as part of the insert above. 2379 */ 2380 newdepth = ext_depth(inode); 2381 /* 2382 * update the extent length after successfull insert of the 2383 * split extent 2384 */ 2385 orig_ex.ee_len = cpu_to_le16(ee_len - 2386 ext4_ext_get_actual_len(ex3)); 2387 if (newdepth != depth) { 2388 depth = newdepth; 2389 ext4_ext_drop_refs(path); 2390 path = ext4_ext_find_extent(inode, iblock, path); 2391 if (IS_ERR(path)) { 2392 err = PTR_ERR(path); 2393 goto out; 2394 } 2395 eh = path[depth].p_hdr; 2396 ex = path[depth].p_ext; 2397 if (ex2 != &newex) 2398 ex2 = ex; 2399 2400 err = ext4_ext_get_access(handle, inode, path + depth); 2401 if (err) 2402 goto out; 2403 } 2404 allocated = max_blocks; 2405 2406 /* If extent has less than EXT4_EXT_ZERO_LEN and we are trying 2407 * to insert a extent in the middle zerout directly 2408 * otherwise give the extent a chance to merge to left 2409 */ 2410 if (le16_to_cpu(orig_ex.ee_len) <= EXT4_EXT_ZERO_LEN && 2411 iblock != ee_block) { 2412 err = ext4_ext_zeroout(inode, &orig_ex); 2413 if (err) 2414 goto fix_extent_len; 2415 /* update the extent length and mark as initialized */ 2416 ex->ee_block = orig_ex.ee_block; 2417 ex->ee_len = orig_ex.ee_len; 2418 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2419 ext4_ext_dirty(handle, inode, path + depth); 2420 /* zero out the first half */ 2421 return allocated; 2422 } 2423 } 2424 /* 2425 * If there was a change of depth as part of the 2426 * insertion of ex3 above, we need to update the length 2427 * of the ex1 extent again here 2428 */ 2429 if (ex1 && ex1 != ex) { 2430 ex1 = ex; 2431 ex1->ee_len = cpu_to_le16(iblock - ee_block); 2432 ext4_ext_mark_uninitialized(ex1); 2433 ex2 = &newex; 2434 } 2435 /* ex2: iblock to iblock + maxblocks-1 : initialised */ 2436 ex2->ee_block = cpu_to_le32(iblock); 2437 ext4_ext_store_pblock(ex2, newblock); 2438 ex2->ee_len = cpu_to_le16(allocated); 2439 if (ex2 != ex) 2440 goto insert; 2441 /* 2442 * New (initialized) extent starts from the first block 2443 * in the current extent. i.e., ex2 == ex 2444 * We have to see if it can be merged with the extent 2445 * on the left. 2446 */ 2447 if (ex2 > EXT_FIRST_EXTENT(eh)) { 2448 /* 2449 * To merge left, pass "ex2 - 1" to try_to_merge(), 2450 * since it merges towards right _only_. 2451 */ 2452 ret = ext4_ext_try_to_merge(inode, path, ex2 - 1); 2453 if (ret) { 2454 err = ext4_ext_correct_indexes(handle, inode, path); 2455 if (err) 2456 goto out; 2457 depth = ext_depth(inode); 2458 ex2--; 2459 } 2460 } 2461 /* 2462 * Try to Merge towards right. This might be required 2463 * only when the whole extent is being written to. 2464 * i.e. ex2 == ex and ex3 == NULL. 2465 */ 2466 if (!ex3) { 2467 ret = ext4_ext_try_to_merge(inode, path, ex2); 2468 if (ret) { 2469 err = ext4_ext_correct_indexes(handle, inode, path); 2470 if (err) 2471 goto out; 2472 } 2473 } 2474 /* Mark modified extent as dirty */ 2475 err = ext4_ext_dirty(handle, inode, path + depth); 2476 goto out; 2477insert: 2478 err = ext4_ext_insert_extent(handle, inode, path, &newex); 2479 if (err == -ENOSPC) { 2480 err = ext4_ext_zeroout(inode, &orig_ex); 2481 if (err) 2482 goto fix_extent_len; 2483 /* update the extent length and mark as initialized */ 2484 ex->ee_block = orig_ex.ee_block; 2485 ex->ee_len = orig_ex.ee_len; 2486 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2487 ext4_ext_dirty(handle, inode, path + depth); 2488 /* zero out the first half */ 2489 return allocated; 2490 } else if (err) 2491 goto fix_extent_len; 2492out: 2493 return err ? err : allocated; 2494 2495fix_extent_len: 2496 ex->ee_block = orig_ex.ee_block; 2497 ex->ee_len = orig_ex.ee_len; 2498 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2499 ext4_ext_mark_uninitialized(ex); 2500 ext4_ext_dirty(handle, inode, path + depth); 2501 return err; 2502} 2503 2504/* 2505 * Block allocation/map/preallocation routine for extents based files 2506 * 2507 * 2508 * Need to be called with 2509 * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block 2510 * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem) 2511 * 2512 * return > 0, number of of blocks already mapped/allocated 2513 * if create == 0 and these are pre-allocated blocks 2514 * buffer head is unmapped 2515 * otherwise blocks are mapped 2516 * 2517 * return = 0, if plain look up failed (blocks have not been allocated) 2518 * buffer head is unmapped 2519 * 2520 * return < 0, error case. 2521 */ 2522int ext4_ext_get_blocks(handle_t *handle, struct inode *inode, 2523 ext4_lblk_t iblock, 2524 unsigned long max_blocks, struct buffer_head *bh_result, 2525 int create, int extend_disksize) 2526{ 2527 struct ext4_ext_path *path = NULL; 2528 struct ext4_extent_header *eh; 2529 struct ext4_extent newex, *ex; 2530 ext4_fsblk_t goal, newblock; 2531 int err = 0, depth, ret; 2532 unsigned long allocated = 0; 2533 struct ext4_allocation_request ar; 2534 2535 __clear_bit(BH_New, &bh_result->b_state); 2536 ext_debug("blocks %u/%lu requested for inode %u\n", 2537 iblock, max_blocks, inode->i_ino); 2538 2539 /* check in cache */ 2540 goal = ext4_ext_in_cache(inode, iblock, &newex); 2541 if (goal) { 2542 if (goal == EXT4_EXT_CACHE_GAP) { 2543 if (!create) { 2544 /* 2545 * block isn't allocated yet and 2546 * user doesn't want to allocate it 2547 */ 2548 goto out2; 2549 } 2550 /* we should allocate requested block */ 2551 } else if (goal == EXT4_EXT_CACHE_EXTENT) { 2552 /* block is already allocated */ 2553 newblock = iblock 2554 - le32_to_cpu(newex.ee_block) 2555 + ext_pblock(&newex); 2556 /* number of remaining blocks in the extent */ 2557 allocated = ext4_ext_get_actual_len(&newex) - 2558 (iblock - le32_to_cpu(newex.ee_block)); 2559 goto out; 2560 } else { 2561 BUG(); 2562 } 2563 } 2564 2565 /* find extent for this block */ 2566 path = ext4_ext_find_extent(inode, iblock, NULL); 2567 if (IS_ERR(path)) { 2568 err = PTR_ERR(path); 2569 path = NULL; 2570 goto out2; 2571 } 2572 2573 depth = ext_depth(inode); 2574 2575 /* 2576 * consistent leaf must not be empty; 2577 * this situation is possible, though, _during_ tree modification; 2578 * this is why assert can't be put in ext4_ext_find_extent() 2579 */ 2580 BUG_ON(path[depth].p_ext == NULL && depth != 0); 2581 eh = path[depth].p_hdr; 2582 2583 ex = path[depth].p_ext; 2584 if (ex) { 2585 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block); 2586 ext4_fsblk_t ee_start = ext_pblock(ex); 2587 unsigned short ee_len; 2588 2589 /* 2590 * Uninitialized extents are treated as holes, except that 2591 * we split out initialized portions during a write. 2592 */ 2593 ee_len = ext4_ext_get_actual_len(ex); 2594 /* if found extent covers block, simply return it */ 2595 if (iblock >= ee_block && iblock < ee_block + ee_len) { 2596 newblock = iblock - ee_block + ee_start; 2597 /* number of remaining blocks in the extent */ 2598 allocated = ee_len - (iblock - ee_block); 2599 ext_debug("%u fit into %lu:%d -> %llu\n", iblock, 2600 ee_block, ee_len, newblock); 2601 2602 /* Do not put uninitialized extent in the cache */ 2603 if (!ext4_ext_is_uninitialized(ex)) { 2604 ext4_ext_put_in_cache(inode, ee_block, 2605 ee_len, ee_start, 2606 EXT4_EXT_CACHE_EXTENT); 2607 goto out; 2608 } 2609 if (create == EXT4_CREATE_UNINITIALIZED_EXT) 2610 goto out; 2611 if (!create) { 2612 /* 2613 * We have blocks reserved already. We 2614 * return allocated blocks so that delalloc 2615 * won't do block reservation for us. But 2616 * the buffer head will be unmapped so that 2617 * a read from the block returns 0s. 2618 */ 2619 if (allocated > max_blocks) 2620 allocated = max_blocks; 2621 /* mark the buffer unwritten */ 2622 __set_bit(BH_Unwritten, &bh_result->b_state); 2623 goto out2; 2624 } 2625 2626 ret = ext4_ext_convert_to_initialized(handle, inode, 2627 path, iblock, 2628 max_blocks); 2629 if (ret <= 0) { 2630 err = ret; 2631 goto out2; 2632 } else 2633 allocated = ret; 2634 goto outnew; 2635 } 2636 } 2637 2638 /* 2639 * requested block isn't allocated yet; 2640 * we couldn't try to create block if create flag is zero 2641 */ 2642 if (!create) { 2643 /* 2644 * put just found gap into cache to speed up 2645 * subsequent requests 2646 */ 2647 ext4_ext_put_gap_in_cache(inode, path, iblock); 2648 goto out2; 2649 } 2650 /* 2651 * Okay, we need to do block allocation. Lazily initialize the block 2652 * allocation info here if necessary. 2653 */ 2654 if (S_ISREG(inode->i_mode) && (!EXT4_I(inode)->i_block_alloc_info)) 2655 ext4_init_block_alloc_info(inode); 2656 2657 /* find neighbour allocated blocks */ 2658 ar.lleft = iblock; 2659 err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft); 2660 if (err) 2661 goto out2; 2662 ar.lright = iblock; 2663 err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright); 2664 if (err) 2665 goto out2; 2666 2667 /* 2668 * See if request is beyond maximum number of blocks we can have in 2669 * a single extent. For an initialized extent this limit is 2670 * EXT_INIT_MAX_LEN and for an uninitialized extent this limit is 2671 * EXT_UNINIT_MAX_LEN. 2672 */ 2673 if (max_blocks > EXT_INIT_MAX_LEN && 2674 create != EXT4_CREATE_UNINITIALIZED_EXT) 2675 max_blocks = EXT_INIT_MAX_LEN; 2676 else if (max_blocks > EXT_UNINIT_MAX_LEN && 2677 create == EXT4_CREATE_UNINITIALIZED_EXT) 2678 max_blocks = EXT_UNINIT_MAX_LEN; 2679 2680 /* Check if we can really insert (iblock)::(iblock+max_blocks) extent */ 2681 newex.ee_block = cpu_to_le32(iblock); 2682 newex.ee_len = cpu_to_le16(max_blocks); 2683 err = ext4_ext_check_overlap(inode, &newex, path); 2684 if (err) 2685 allocated = ext4_ext_get_actual_len(&newex); 2686 else 2687 allocated = max_blocks; 2688 2689 /* allocate new block */ 2690 ar.inode = inode; 2691 ar.goal = ext4_ext_find_goal(inode, path, iblock); 2692 ar.logical = iblock; 2693 ar.len = allocated; 2694 if (S_ISREG(inode->i_mode)) 2695 ar.flags = EXT4_MB_HINT_DATA; 2696 else 2697 /* disable in-core preallocation for non-regular files */ 2698 ar.flags = 0; 2699 newblock = ext4_mb_new_blocks(handle, &ar, &err); 2700 if (!newblock) 2701 goto out2; 2702 ext_debug("allocate new block: goal %llu, found %llu/%lu\n", 2703 goal, newblock, allocated); 2704 2705 /* try to insert new extent into found leaf and return */ 2706 ext4_ext_store_pblock(&newex, newblock); 2707 newex.ee_len = cpu_to_le16(ar.len); 2708 if (create == EXT4_CREATE_UNINITIALIZED_EXT) /* Mark uninitialized */ 2709 ext4_ext_mark_uninitialized(&newex); 2710 err = ext4_ext_insert_extent(handle, inode, path, &newex); 2711 if (err) { 2712 /* free data blocks we just allocated */ 2713 /* not a good idea to call discard here directly, 2714 * but otherwise we'd need to call it every free() */ 2715 ext4_mb_discard_inode_preallocations(inode); 2716 ext4_free_blocks(handle, inode, ext_pblock(&newex), 2717 ext4_ext_get_actual_len(&newex), 0); 2718 goto out2; 2719 } 2720 2721 /* previous routine could use block we allocated */ 2722 newblock = ext_pblock(&newex); 2723 allocated = ext4_ext_get_actual_len(&newex); 2724outnew: 2725 if (extend_disksize && inode->i_size > EXT4_I(inode)->i_disksize) 2726 EXT4_I(inode)->i_disksize = inode->i_size; 2727 2728 __set_bit(BH_New, &bh_result->b_state); 2729 2730 /* Cache only when it is _not_ an uninitialized extent */ 2731 if (create != EXT4_CREATE_UNINITIALIZED_EXT) 2732 ext4_ext_put_in_cache(inode, iblock, allocated, newblock, 2733 EXT4_EXT_CACHE_EXTENT); 2734out: 2735 if (allocated > max_blocks) 2736 allocated = max_blocks; 2737 ext4_ext_show_leaf(inode, path); 2738 __set_bit(BH_Mapped, &bh_result->b_state); 2739 bh_result->b_bdev = inode->i_sb->s_bdev; 2740 bh_result->b_blocknr = newblock; 2741out2: 2742 if (path) { 2743 ext4_ext_drop_refs(path); 2744 kfree(path); 2745 } 2746 return err ? err : allocated; 2747} 2748 2749void ext4_ext_truncate(struct inode * inode, struct page *page) 2750{ 2751 struct address_space *mapping = inode->i_mapping; 2752 struct super_block *sb = inode->i_sb; 2753 ext4_lblk_t last_block; 2754 handle_t *handle; 2755 int err = 0; 2756 2757 /* 2758 * probably first extent we're gonna free will be last in block 2759 */ 2760 err = ext4_writepage_trans_blocks(inode) + 3; 2761 handle = ext4_journal_start(inode, err); 2762 if (IS_ERR(handle)) { 2763 if (page) { 2764 clear_highpage(page); 2765 flush_dcache_page(page); 2766 unlock_page(page); 2767 page_cache_release(page); 2768 } 2769 return; 2770 } 2771 2772 if (page) 2773 ext4_block_truncate_page(handle, page, mapping, inode->i_size); 2774 2775 down_write(&EXT4_I(inode)->i_data_sem); 2776 ext4_ext_invalidate_cache(inode); 2777 2778 ext4_mb_discard_inode_preallocations(inode); 2779 2780 /* 2781 * TODO: optimization is possible here. 2782 * Probably we need not scan at all, 2783 * because page truncation is enough. 2784 */ 2785 if (ext4_orphan_add(handle, inode)) 2786 goto out_stop; 2787 2788 /* we have to know where to truncate from in crash case */ 2789 EXT4_I(inode)->i_disksize = inode->i_size; 2790 ext4_mark_inode_dirty(handle, inode); 2791 2792 last_block = (inode->i_size + sb->s_blocksize - 1) 2793 >> EXT4_BLOCK_SIZE_BITS(sb); 2794 err = ext4_ext_remove_space(inode, last_block); 2795 2796 /* In a multi-transaction truncate, we only make the final 2797 * transaction synchronous. 2798 */ 2799 if (IS_SYNC(inode)) 2800 handle->h_sync = 1; 2801 2802out_stop: 2803 /* 2804 * If this was a simple ftruncate() and the file will remain alive, 2805 * then we need to clear up the orphan record which we created above. 2806 * However, if this was a real unlink then we were called by 2807 * ext4_delete_inode(), and we allow that function to clean up the 2808 * orphan info for us. 2809 */ 2810 if (inode->i_nlink) 2811 ext4_orphan_del(handle, inode); 2812 2813 up_write(&EXT4_I(inode)->i_data_sem); 2814 inode->i_mtime = inode->i_ctime = ext4_current_time(inode); 2815 ext4_mark_inode_dirty(handle, inode); 2816 ext4_journal_stop(handle); 2817} 2818 2819/* 2820 * ext4_ext_writepage_trans_blocks: 2821 * calculate max number of blocks we could modify 2822 * in order to allocate new block for an inode 2823 */ 2824int ext4_ext_writepage_trans_blocks(struct inode *inode, int num) 2825{ 2826 int needed; 2827 2828 needed = ext4_ext_calc_credits_for_insert(inode, NULL); 2829 2830 /* caller wants to allocate num blocks, but note it includes sb */ 2831 needed = needed * num - (num - 1); 2832 2833#ifdef CONFIG_QUOTA 2834 needed += 2 * EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb); 2835#endif 2836 2837 return needed; 2838} 2839 2840static void ext4_falloc_update_inode(struct inode *inode, 2841 int mode, loff_t new_size, int update_ctime) 2842{ 2843 struct timespec now; 2844 2845 if (update_ctime) { 2846 now = current_fs_time(inode->i_sb); 2847 if (!timespec_equal(&inode->i_ctime, &now)) 2848 inode->i_ctime = now; 2849 } 2850 /* 2851 * Update only when preallocation was requested beyond 2852 * the file size. 2853 */ 2854 if (!(mode & FALLOC_FL_KEEP_SIZE) && 2855 new_size > i_size_read(inode)) { 2856 i_size_write(inode, new_size); 2857 EXT4_I(inode)->i_disksize = new_size; 2858 } 2859 2860} 2861 2862/* 2863 * preallocate space for a file. This implements ext4's fallocate inode 2864 * operation, which gets called from sys_fallocate system call. 2865 * For block-mapped files, posix_fallocate should fall back to the method 2866 * of writing zeroes to the required new blocks (the same behavior which is 2867 * expected for file systems which do not support fallocate() system call). 2868 */ 2869long ext4_fallocate(struct inode *inode, int mode, loff_t offset, loff_t len) 2870{ 2871 handle_t *handle; 2872 ext4_lblk_t block; 2873 loff_t new_size; 2874 unsigned long max_blocks; 2875 int ret = 0; 2876 int ret2 = 0; 2877 int retries = 0; 2878 struct buffer_head map_bh; 2879 unsigned int credits, blkbits = inode->i_blkbits; 2880 2881 /* 2882 * currently supporting (pre)allocate mode for extent-based 2883 * files _only_ 2884 */ 2885 if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) 2886 return -EOPNOTSUPP; 2887 2888 /* preallocation to directories is currently not supported */ 2889 if (S_ISDIR(inode->i_mode)) 2890 return -ENODEV; 2891 2892 block = offset >> blkbits; 2893 /* 2894 * We can't just convert len to max_blocks because 2895 * If blocksize = 4096 offset = 3072 and len = 2048 2896 */ 2897 max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits) 2898 - block; 2899 /* 2900 * credits to insert 1 extent into extent tree + buffers to be able to 2901 * modify 1 super block, 1 block bitmap and 1 group descriptor. 2902 */ 2903 credits = EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + 3; 2904 mutex_lock(&inode->i_mutex); 2905retry: 2906 while (ret >= 0 && ret < max_blocks) { 2907 block = block + ret; 2908 max_blocks = max_blocks - ret; 2909 handle = ext4_journal_start(inode, credits); 2910 if (IS_ERR(handle)) { 2911 ret = PTR_ERR(handle); 2912 break; 2913 } 2914 ret = ext4_get_blocks_wrap(handle, inode, block, 2915 max_blocks, &map_bh, 2916 EXT4_CREATE_UNINITIALIZED_EXT, 0); 2917 if (ret <= 0) { 2918#ifdef EXT4FS_DEBUG 2919 WARN_ON(ret <= 0); 2920 printk(KERN_ERR "%s: ext4_ext_get_blocks " 2921 "returned error inode#%lu, block=%u, " 2922 "max_blocks=%lu", __func__, 2923 inode->i_ino, block, max_blocks); 2924#endif 2925 ext4_mark_inode_dirty(handle, inode); 2926 ret2 = ext4_journal_stop(handle); 2927 break; 2928 } 2929 if ((block + ret) >= (EXT4_BLOCK_ALIGN(offset + len, 2930 blkbits) >> blkbits)) 2931 new_size = offset + len; 2932 else 2933 new_size = (block + ret) << blkbits; 2934 2935 ext4_falloc_update_inode(inode, mode, new_size, 2936 buffer_new(&map_bh)); 2937 ext4_mark_inode_dirty(handle, inode); 2938 ret2 = ext4_journal_stop(handle); 2939 if (ret2) 2940 break; 2941 } 2942 if (ret == -ENOSPC && 2943 ext4_should_retry_alloc(inode->i_sb, &retries)) { 2944 ret = 0; 2945 goto retry; 2946 } 2947 mutex_unlock(&inode->i_mutex); 2948 return ret > 0 ? ret2 : ret; 2949} 2950