1 /* 2 * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com 3 * Written by Alex Tomas <alex@clusterfs.com> 4 * 5 * Architecture independence: 6 * Copyright (c) 2005, Bull S.A. 7 * Written by Pierre Peiffer <pierre.peiffer@bull.net> 8 * 9 * This program is free software; you can redistribute it and/or modify 10 * it under the terms of the GNU General Public License version 2 as 11 * published by the Free Software Foundation. 12 * 13 * This program is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 * GNU General Public License for more details. 17 * 18 * You should have received a copy of the GNU General Public Licens 19 * along with this program; if not, write to the Free Software 20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111- 21 */ 22 23 /* 24 * Extents support for EXT4 25 * 26 * TODO: 27 * - ext4*_error() should be used in some situations 28 * - analyze all BUG()/BUG_ON(), use -EIO where appropriate 29 * - smart tree reduction 30 */ 31 32 #include <linux/module.h> 33 #include <linux/fs.h> 34 #include <linux/time.h> 35 #include <linux/jbd2.h> 36 #include <linux/highuid.h> 37 #include <linux/pagemap.h> 38 #include <linux/quotaops.h> 39 #include <linux/string.h> 40 #include <linux/slab.h> 41 #include <linux/falloc.h> 42 #include <asm/uaccess.h> 43 #include <linux/fiemap.h> 44 #include "ext4_jbd2.h" 45 #include "ext4_extents.h" 46 47 48 /* 49 * ext_pblock: 50 * combine low and high parts of physical block number into ext4_fsblk_t 51 */ 52 static ext4_fsblk_t ext_pblock(struct ext4_extent *ex) 53 { 54 ext4_fsblk_t block; 55 56 block = le32_to_cpu(ex->ee_start_lo); 57 block |= ((ext4_fsblk_t) le16_to_cpu(ex->ee_start_hi) << 31) << 1; 58 return block; 59 } 60 61 /* 62 * idx_pblock: 63 * combine low and high parts of a leaf physical block number into ext4_fsblk_t 64 */ 65 ext4_fsblk_t idx_pblock(struct ext4_extent_idx *ix) 66 { 67 ext4_fsblk_t block; 68 69 block = le32_to_cpu(ix->ei_leaf_lo); 70 block |= ((ext4_fsblk_t) le16_to_cpu(ix->ei_leaf_hi) << 31) << 1; 71 return block; 72 } 73 74 /* 75 * ext4_ext_store_pblock: 76 * stores a large physical block number into an extent struct, 77 * breaking it into parts 78 */ 79 void ext4_ext_store_pblock(struct ext4_extent *ex, ext4_fsblk_t pb) 80 { 81 ex->ee_start_lo = cpu_to_le32((unsigned long) (pb & 0xffffffff)); 82 ex->ee_start_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) & 0xffff); 83 } 84 85 /* 86 * ext4_idx_store_pblock: 87 * stores a large physical block number into an index struct, 88 * breaking it into parts 89 */ 90 static void ext4_idx_store_pblock(struct ext4_extent_idx *ix, ext4_fsblk_t pb) 91 { 92 ix->ei_leaf_lo = cpu_to_le32((unsigned long) (pb & 0xffffffff)); 93 ix->ei_leaf_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) & 0xffff); 94 } 95 96 static int ext4_ext_journal_restart(handle_t *handle, int needed) 97 { 98 int err; 99 100 if (handle->h_buffer_credits > needed) 101 return 0; 102 err = ext4_journal_extend(handle, needed); 103 if (err <= 0) 104 return err; 105 return ext4_journal_restart(handle, needed); 106 } 107 108 /* 109 * could return: 110 * - EROFS 111 * - ENOMEM 112 */ 113 static int ext4_ext_get_access(handle_t *handle, struct inode *inode, 114 struct ext4_ext_path *path) 115 { 116 if (path->p_bh) { 117 /* path points to block */ 118 return ext4_journal_get_write_access(handle, path->p_bh); 119 } 120 /* path points to leaf/index in inode body */ 121 /* we use in-core data, no need to protect them */ 122 return 0; 123 } 124 125 /* 126 * could return: 127 * - EROFS 128 * - ENOMEM 129 * - EIO 130 */ 131 static int ext4_ext_dirty(handle_t *handle, struct inode *inode, 132 struct ext4_ext_path *path) 133 { 134 int err; 135 if (path->p_bh) { 136 /* path points to block */ 137 err = ext4_journal_dirty_metadata(handle, path->p_bh); 138 } else { 139 /* path points to leaf/index in inode body */ 140 err = ext4_mark_inode_dirty(handle, inode); 141 } 142 return err; 143 } 144 145 static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode, 146 struct ext4_ext_path *path, 147 ext4_lblk_t block) 148 { 149 struct ext4_inode_info *ei = EXT4_I(inode); 150 ext4_fsblk_t bg_start; 151 ext4_fsblk_t last_block; 152 ext4_grpblk_t colour; 153 int depth; 154 155 if (path) { 156 struct ext4_extent *ex; 157 depth = path->p_depth; 158 159 /* try to predict block placement */ 160 ex = path[depth].p_ext; 161 if (ex) 162 return ext_pblock(ex)+(block-le32_to_cpu(ex->ee_block)); 163 164 /* it looks like index is empty; 165 * try to find starting block from index itself */ 166 if (path[depth].p_bh) 167 return path[depth].p_bh->b_blocknr; 168 } 169 170 /* OK. use inode's group */ 171 bg_start = (ei->i_block_group * EXT4_BLOCKS_PER_GROUP(inode->i_sb)) + 172 le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_first_data_block); 173 last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1; 174 175 if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block) 176 colour = (current->pid % 16) * 177 (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16); 178 else 179 colour = (current->pid % 16) * ((last_block - bg_start) / 16); 180 return bg_start + colour + block; 181 } 182 183 /* 184 * Allocation for a meta data block 185 */ 186 static ext4_fsblk_t 187 ext4_ext_new_meta_block(handle_t *handle, struct inode *inode, 188 struct ext4_ext_path *path, 189 struct ext4_extent *ex, int *err) 190 { 191 ext4_fsblk_t goal, newblock; 192 193 goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block)); 194 newblock = ext4_new_meta_block(handle, inode, goal, err); 195 return newblock; 196 } 197 198 static int ext4_ext_space_block(struct inode *inode) 199 { 200 int size; 201 202 size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header)) 203 / sizeof(struct ext4_extent); 204 #ifdef AGGRESSIVE_TEST 205 if (size > 6) 206 size = 6; 207 #endif 208 return size; 209 } 210 211 static int ext4_ext_space_block_idx(struct inode *inode) 212 { 213 int size; 214 215 size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header)) 216 / sizeof(struct ext4_extent_idx); 217 #ifdef AGGRESSIVE_TEST 218 if (size > 5) 219 size = 5; 220 #endif 221 return size; 222 } 223 224 static int ext4_ext_space_root(struct inode *inode) 225 { 226 int size; 227 228 size = sizeof(EXT4_I(inode)->i_data); 229 size -= sizeof(struct ext4_extent_header); 230 size /= sizeof(struct ext4_extent); 231 #ifdef AGGRESSIVE_TEST 232 if (size > 3) 233 size = 3; 234 #endif 235 return size; 236 } 237 238 static int ext4_ext_space_root_idx(struct inode *inode) 239 { 240 int size; 241 242 size = sizeof(EXT4_I(inode)->i_data); 243 size -= sizeof(struct ext4_extent_header); 244 size /= sizeof(struct ext4_extent_idx); 245 #ifdef AGGRESSIVE_TEST 246 if (size > 4) 247 size = 4; 248 #endif 249 return size; 250 } 251 252 /* 253 * Calculate the number of metadata blocks needed 254 * to allocate @blocks 255 * Worse case is one block per extent 256 */ 257 int ext4_ext_calc_metadata_amount(struct inode *inode, int blocks) 258 { 259 int lcap, icap, rcap, leafs, idxs, num; 260 int newextents = blocks; 261 262 rcap = ext4_ext_space_root_idx(inode); 263 lcap = ext4_ext_space_block(inode); 264 icap = ext4_ext_space_block_idx(inode); 265 266 /* number of new leaf blocks needed */ 267 num = leafs = (newextents + lcap - 1) / lcap; 268 269 /* 270 * Worse case, we need separate index block(s) 271 * to link all new leaf blocks 272 */ 273 idxs = (leafs + icap - 1) / icap; 274 do { 275 num += idxs; 276 idxs = (idxs + icap - 1) / icap; 277 } while (idxs > rcap); 278 279 return num; 280 } 281 282 static int 283 ext4_ext_max_entries(struct inode *inode, int depth) 284 { 285 int max; 286 287 if (depth == ext_depth(inode)) { 288 if (depth == 0) 289 max = ext4_ext_space_root(inode); 290 else 291 max = ext4_ext_space_root_idx(inode); 292 } else { 293 if (depth == 0) 294 max = ext4_ext_space_block(inode); 295 else 296 max = ext4_ext_space_block_idx(inode); 297 } 298 299 return max; 300 } 301 302 static int __ext4_ext_check_header(const char *function, struct inode *inode, 303 struct ext4_extent_header *eh, 304 int depth) 305 { 306 const char *error_msg; 307 int max = 0; 308 309 if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) { 310 error_msg = "invalid magic"; 311 goto corrupted; 312 } 313 if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) { 314 error_msg = "unexpected eh_depth"; 315 goto corrupted; 316 } 317 if (unlikely(eh->eh_max == 0)) { 318 error_msg = "invalid eh_max"; 319 goto corrupted; 320 } 321 max = ext4_ext_max_entries(inode, depth); 322 if (unlikely(le16_to_cpu(eh->eh_max) > max)) { 323 error_msg = "too large eh_max"; 324 goto corrupted; 325 } 326 if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) { 327 error_msg = "invalid eh_entries"; 328 goto corrupted; 329 } 330 return 0; 331 332 corrupted: 333 ext4_error(inode->i_sb, function, 334 "bad header in inode #%lu: %s - magic %x, " 335 "entries %u, max %u(%u), depth %u(%u)", 336 inode->i_ino, error_msg, le16_to_cpu(eh->eh_magic), 337 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max), 338 max, le16_to_cpu(eh->eh_depth), depth); 339 340 return -EIO; 341 } 342 343 #define ext4_ext_check_header(inode, eh, depth) \ 344 __ext4_ext_check_header(__func__, inode, eh, depth) 345 346 #ifdef EXT_DEBUG 347 static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path) 348 { 349 int k, l = path->p_depth; 350 351 ext_debug("path:"); 352 for (k = 0; k <= l; k++, path++) { 353 if (path->p_idx) { 354 ext_debug(" %d->%llu", le32_to_cpu(path->p_idx->ei_block), 355 idx_pblock(path->p_idx)); 356 } else if (path->p_ext) { 357 ext_debug(" %d:%d:%llu ", 358 le32_to_cpu(path->p_ext->ee_block), 359 ext4_ext_get_actual_len(path->p_ext), 360 ext_pblock(path->p_ext)); 361 } else 362 ext_debug(" []"); 363 } 364 ext_debug("\n"); 365 } 366 367 static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path) 368 { 369 int depth = ext_depth(inode); 370 struct ext4_extent_header *eh; 371 struct ext4_extent *ex; 372 int i; 373 374 if (!path) 375 return; 376 377 eh = path[depth].p_hdr; 378 ex = EXT_FIRST_EXTENT(eh); 379 380 for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) { 381 ext_debug("%d:%d:%llu ", le32_to_cpu(ex->ee_block), 382 ext4_ext_get_actual_len(ex), ext_pblock(ex)); 383 } 384 ext_debug("\n"); 385 } 386 #else 387 #define ext4_ext_show_path(inode, path) 388 #define ext4_ext_show_leaf(inode, path) 389 #endif 390 391 void ext4_ext_drop_refs(struct ext4_ext_path *path) 392 { 393 int depth = path->p_depth; 394 int i; 395 396 for (i = 0; i <= depth; i++, path++) 397 if (path->p_bh) { 398 brelse(path->p_bh); 399 path->p_bh = NULL; 400 } 401 } 402 403 /* 404 * ext4_ext_binsearch_idx: 405 * binary search for the closest index of the given block 406 * the header must be checked before calling this 407 */ 408 static void 409 ext4_ext_binsearch_idx(struct inode *inode, 410 struct ext4_ext_path *path, ext4_lblk_t block) 411 { 412 struct ext4_extent_header *eh = path->p_hdr; 413 struct ext4_extent_idx *r, *l, *m; 414 415 416 ext_debug("binsearch for %u(idx): ", block); 417 418 l = EXT_FIRST_INDEX(eh) + 1; 419 r = EXT_LAST_INDEX(eh); 420 while (l <= r) { 421 m = l + (r - l) / 2; 422 if (block < le32_to_cpu(m->ei_block)) 423 r = m - 1; 424 else 425 l = m + 1; 426 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ei_block), 427 m, le32_to_cpu(m->ei_block), 428 r, le32_to_cpu(r->ei_block)); 429 } 430 431 path->p_idx = l - 1; 432 ext_debug(" -> %d->%lld ", le32_to_cpu(path->p_idx->ei_block), 433 idx_pblock(path->p_idx)); 434 435 #ifdef CHECK_BINSEARCH 436 { 437 struct ext4_extent_idx *chix, *ix; 438 int k; 439 440 chix = ix = EXT_FIRST_INDEX(eh); 441 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) { 442 if (k != 0 && 443 le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) { 444 printk(KERN_DEBUG "k=%d, ix=0x%p, " 445 "first=0x%p\n", k, 446 ix, EXT_FIRST_INDEX(eh)); 447 printk(KERN_DEBUG "%u <= %u\n", 448 le32_to_cpu(ix->ei_block), 449 le32_to_cpu(ix[-1].ei_block)); 450 } 451 BUG_ON(k && le32_to_cpu(ix->ei_block) 452 <= le32_to_cpu(ix[-1].ei_block)); 453 if (block < le32_to_cpu(ix->ei_block)) 454 break; 455 chix = ix; 456 } 457 BUG_ON(chix != path->p_idx); 458 } 459 #endif 460 461 } 462 463 /* 464 * ext4_ext_binsearch: 465 * binary search for closest extent of the given block 466 * the header must be checked before calling this 467 */ 468 static void 469 ext4_ext_binsearch(struct inode *inode, 470 struct ext4_ext_path *path, ext4_lblk_t block) 471 { 472 struct ext4_extent_header *eh = path->p_hdr; 473 struct ext4_extent *r, *l, *m; 474 475 if (eh->eh_entries == 0) { 476 /* 477 * this leaf is empty: 478 * we get such a leaf in split/add case 479 */ 480 return; 481 } 482 483 ext_debug("binsearch for %u: ", block); 484 485 l = EXT_FIRST_EXTENT(eh) + 1; 486 r = EXT_LAST_EXTENT(eh); 487 488 while (l <= r) { 489 m = l + (r - l) / 2; 490 if (block < le32_to_cpu(m->ee_block)) 491 r = m - 1; 492 else 493 l = m + 1; 494 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ee_block), 495 m, le32_to_cpu(m->ee_block), 496 r, le32_to_cpu(r->ee_block)); 497 } 498 499 path->p_ext = l - 1; 500 ext_debug(" -> %d:%llu:%d ", 501 le32_to_cpu(path->p_ext->ee_block), 502 ext_pblock(path->p_ext), 503 ext4_ext_get_actual_len(path->p_ext)); 504 505 #ifdef CHECK_BINSEARCH 506 { 507 struct ext4_extent *chex, *ex; 508 int k; 509 510 chex = ex = EXT_FIRST_EXTENT(eh); 511 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) { 512 BUG_ON(k && le32_to_cpu(ex->ee_block) 513 <= le32_to_cpu(ex[-1].ee_block)); 514 if (block < le32_to_cpu(ex->ee_block)) 515 break; 516 chex = ex; 517 } 518 BUG_ON(chex != path->p_ext); 519 } 520 #endif 521 522 } 523 524 int ext4_ext_tree_init(handle_t *handle, struct inode *inode) 525 { 526 struct ext4_extent_header *eh; 527 528 eh = ext_inode_hdr(inode); 529 eh->eh_depth = 0; 530 eh->eh_entries = 0; 531 eh->eh_magic = EXT4_EXT_MAGIC; 532 eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode)); 533 ext4_mark_inode_dirty(handle, inode); 534 ext4_ext_invalidate_cache(inode); 535 return 0; 536 } 537 538 struct ext4_ext_path * 539 ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block, 540 struct ext4_ext_path *path) 541 { 542 struct ext4_extent_header *eh; 543 struct buffer_head *bh; 544 short int depth, i, ppos = 0, alloc = 0; 545 546 eh = ext_inode_hdr(inode); 547 depth = ext_depth(inode); 548 if (ext4_ext_check_header(inode, eh, depth)) 549 return ERR_PTR(-EIO); 550 551 552 /* account possible depth increase */ 553 if (!path) { 554 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2), 555 GFP_NOFS); 556 if (!path) 557 return ERR_PTR(-ENOMEM); 558 alloc = 1; 559 } 560 path[0].p_hdr = eh; 561 path[0].p_bh = NULL; 562 563 i = depth; 564 /* walk through the tree */ 565 while (i) { 566 ext_debug("depth %d: num %d, max %d\n", 567 ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max)); 568 569 ext4_ext_binsearch_idx(inode, path + ppos, block); 570 path[ppos].p_block = idx_pblock(path[ppos].p_idx); 571 path[ppos].p_depth = i; 572 path[ppos].p_ext = NULL; 573 574 bh = sb_bread(inode->i_sb, path[ppos].p_block); 575 if (!bh) 576 goto err; 577 578 eh = ext_block_hdr(bh); 579 ppos++; 580 BUG_ON(ppos > depth); 581 path[ppos].p_bh = bh; 582 path[ppos].p_hdr = eh; 583 i--; 584 585 if (ext4_ext_check_header(inode, eh, i)) 586 goto err; 587 } 588 589 path[ppos].p_depth = i; 590 path[ppos].p_ext = NULL; 591 path[ppos].p_idx = NULL; 592 593 /* find extent */ 594 ext4_ext_binsearch(inode, path + ppos, block); 595 /* if not an empty leaf */ 596 if (path[ppos].p_ext) 597 path[ppos].p_block = ext_pblock(path[ppos].p_ext); 598 599 ext4_ext_show_path(inode, path); 600 601 return path; 602 603 err: 604 ext4_ext_drop_refs(path); 605 if (alloc) 606 kfree(path); 607 return ERR_PTR(-EIO); 608 } 609 610 /* 611 * ext4_ext_insert_index: 612 * insert new index [@logical;@ptr] into the block at @curp; 613 * check where to insert: before @curp or after @curp 614 */ 615 static int ext4_ext_insert_index(handle_t *handle, struct inode *inode, 616 struct ext4_ext_path *curp, 617 int logical, ext4_fsblk_t ptr) 618 { 619 struct ext4_extent_idx *ix; 620 int len, err; 621 622 err = ext4_ext_get_access(handle, inode, curp); 623 if (err) 624 return err; 625 626 BUG_ON(logical == le32_to_cpu(curp->p_idx->ei_block)); 627 len = EXT_MAX_INDEX(curp->p_hdr) - curp->p_idx; 628 if (logical > le32_to_cpu(curp->p_idx->ei_block)) { 629 /* insert after */ 630 if (curp->p_idx != EXT_LAST_INDEX(curp->p_hdr)) { 631 len = (len - 1) * sizeof(struct ext4_extent_idx); 632 len = len < 0 ? 0 : len; 633 ext_debug("insert new index %d after: %llu. " 634 "move %d from 0x%p to 0x%p\n", 635 logical, ptr, len, 636 (curp->p_idx + 1), (curp->p_idx + 2)); 637 memmove(curp->p_idx + 2, curp->p_idx + 1, len); 638 } 639 ix = curp->p_idx + 1; 640 } else { 641 /* insert before */ 642 len = len * sizeof(struct ext4_extent_idx); 643 len = len < 0 ? 0 : len; 644 ext_debug("insert new index %d before: %llu. " 645 "move %d from 0x%p to 0x%p\n", 646 logical, ptr, len, 647 curp->p_idx, (curp->p_idx + 1)); 648 memmove(curp->p_idx + 1, curp->p_idx, len); 649 ix = curp->p_idx; 650 } 651 652 ix->ei_block = cpu_to_le32(logical); 653 ext4_idx_store_pblock(ix, ptr); 654 le16_add_cpu(&curp->p_hdr->eh_entries, 1); 655 656 BUG_ON(le16_to_cpu(curp->p_hdr->eh_entries) 657 > le16_to_cpu(curp->p_hdr->eh_max)); 658 BUG_ON(ix > EXT_LAST_INDEX(curp->p_hdr)); 659 660 err = ext4_ext_dirty(handle, inode, curp); 661 ext4_std_error(inode->i_sb, err); 662 663 return err; 664 } 665 666 /* 667 * ext4_ext_split: 668 * inserts new subtree into the path, using free index entry 669 * at depth @at: 670 * - allocates all needed blocks (new leaf and all intermediate index blocks) 671 * - makes decision where to split 672 * - moves remaining extents and index entries (right to the split point) 673 * into the newly allocated blocks 674 * - initializes subtree 675 */ 676 static int ext4_ext_split(handle_t *handle, struct inode *inode, 677 struct ext4_ext_path *path, 678 struct ext4_extent *newext, int at) 679 { 680 struct buffer_head *bh = NULL; 681 int depth = ext_depth(inode); 682 struct ext4_extent_header *neh; 683 struct ext4_extent_idx *fidx; 684 struct ext4_extent *ex; 685 int i = at, k, m, a; 686 ext4_fsblk_t newblock, oldblock; 687 __le32 border; 688 ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */ 689 int err = 0; 690 691 /* make decision: where to split? */ 692 /* FIXME: now decision is simplest: at current extent */ 693 694 /* if current leaf will be split, then we should use 695 * border from split point */ 696 BUG_ON(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr)); 697 if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) { 698 border = path[depth].p_ext[1].ee_block; 699 ext_debug("leaf will be split." 700 " next leaf starts at %d\n", 701 le32_to_cpu(border)); 702 } else { 703 border = newext->ee_block; 704 ext_debug("leaf will be added." 705 " next leaf starts at %d\n", 706 le32_to_cpu(border)); 707 } 708 709 /* 710 * If error occurs, then we break processing 711 * and mark filesystem read-only. index won't 712 * be inserted and tree will be in consistent 713 * state. Next mount will repair buffers too. 714 */ 715 716 /* 717 * Get array to track all allocated blocks. 718 * We need this to handle errors and free blocks 719 * upon them. 720 */ 721 ablocks = kzalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS); 722 if (!ablocks) 723 return -ENOMEM; 724 725 /* allocate all needed blocks */ 726 ext_debug("allocate %d blocks for indexes/leaf\n", depth - at); 727 for (a = 0; a < depth - at; a++) { 728 newblock = ext4_ext_new_meta_block(handle, inode, path, 729 newext, &err); 730 if (newblock == 0) 731 goto cleanup; 732 ablocks[a] = newblock; 733 } 734 735 /* initialize new leaf */ 736 newblock = ablocks[--a]; 737 BUG_ON(newblock == 0); 738 bh = sb_getblk(inode->i_sb, newblock); 739 if (!bh) { 740 err = -EIO; 741 goto cleanup; 742 } 743 lock_buffer(bh); 744 745 err = ext4_journal_get_create_access(handle, bh); 746 if (err) 747 goto cleanup; 748 749 neh = ext_block_hdr(bh); 750 neh->eh_entries = 0; 751 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode)); 752 neh->eh_magic = EXT4_EXT_MAGIC; 753 neh->eh_depth = 0; 754 ex = EXT_FIRST_EXTENT(neh); 755 756 /* move remainder of path[depth] to the new leaf */ 757 BUG_ON(path[depth].p_hdr->eh_entries != path[depth].p_hdr->eh_max); 758 /* start copy from next extent */ 759 /* TODO: we could do it by single memmove */ 760 m = 0; 761 path[depth].p_ext++; 762 while (path[depth].p_ext <= 763 EXT_MAX_EXTENT(path[depth].p_hdr)) { 764 ext_debug("move %d:%llu:%d in new leaf %llu\n", 765 le32_to_cpu(path[depth].p_ext->ee_block), 766 ext_pblock(path[depth].p_ext), 767 ext4_ext_get_actual_len(path[depth].p_ext), 768 newblock); 769 /*memmove(ex++, path[depth].p_ext++, 770 sizeof(struct ext4_extent)); 771 neh->eh_entries++;*/ 772 path[depth].p_ext++; 773 m++; 774 } 775 if (m) { 776 memmove(ex, path[depth].p_ext-m, sizeof(struct ext4_extent)*m); 777 le16_add_cpu(&neh->eh_entries, m); 778 } 779 780 set_buffer_uptodate(bh); 781 unlock_buffer(bh); 782 783 err = ext4_journal_dirty_metadata(handle, bh); 784 if (err) 785 goto cleanup; 786 brelse(bh); 787 bh = NULL; 788 789 /* correct old leaf */ 790 if (m) { 791 err = ext4_ext_get_access(handle, inode, path + depth); 792 if (err) 793 goto cleanup; 794 le16_add_cpu(&path[depth].p_hdr->eh_entries, -m); 795 err = ext4_ext_dirty(handle, inode, path + depth); 796 if (err) 797 goto cleanup; 798 799 } 800 801 /* create intermediate indexes */ 802 k = depth - at - 1; 803 BUG_ON(k < 0); 804 if (k) 805 ext_debug("create %d intermediate indices\n", k); 806 /* insert new index into current index block */ 807 /* current depth stored in i var */ 808 i = depth - 1; 809 while (k--) { 810 oldblock = newblock; 811 newblock = ablocks[--a]; 812 bh = sb_getblk(inode->i_sb, newblock); 813 if (!bh) { 814 err = -EIO; 815 goto cleanup; 816 } 817 lock_buffer(bh); 818 819 err = ext4_journal_get_create_access(handle, bh); 820 if (err) 821 goto cleanup; 822 823 neh = ext_block_hdr(bh); 824 neh->eh_entries = cpu_to_le16(1); 825 neh->eh_magic = EXT4_EXT_MAGIC; 826 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode)); 827 neh->eh_depth = cpu_to_le16(depth - i); 828 fidx = EXT_FIRST_INDEX(neh); 829 fidx->ei_block = border; 830 ext4_idx_store_pblock(fidx, oldblock); 831 832 ext_debug("int.index at %d (block %llu): %u -> %llu\n", 833 i, newblock, le32_to_cpu(border), oldblock); 834 /* copy indexes */ 835 m = 0; 836 path[i].p_idx++; 837 838 ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx, 839 EXT_MAX_INDEX(path[i].p_hdr)); 840 BUG_ON(EXT_MAX_INDEX(path[i].p_hdr) != 841 EXT_LAST_INDEX(path[i].p_hdr)); 842 while (path[i].p_idx <= EXT_MAX_INDEX(path[i].p_hdr)) { 843 ext_debug("%d: move %d:%llu in new index %llu\n", i, 844 le32_to_cpu(path[i].p_idx->ei_block), 845 idx_pblock(path[i].p_idx), 846 newblock); 847 /*memmove(++fidx, path[i].p_idx++, 848 sizeof(struct ext4_extent_idx)); 849 neh->eh_entries++; 850 BUG_ON(neh->eh_entries > neh->eh_max);*/ 851 path[i].p_idx++; 852 m++; 853 } 854 if (m) { 855 memmove(++fidx, path[i].p_idx - m, 856 sizeof(struct ext4_extent_idx) * m); 857 le16_add_cpu(&neh->eh_entries, m); 858 } 859 set_buffer_uptodate(bh); 860 unlock_buffer(bh); 861 862 err = ext4_journal_dirty_metadata(handle, bh); 863 if (err) 864 goto cleanup; 865 brelse(bh); 866 bh = NULL; 867 868 /* correct old index */ 869 if (m) { 870 err = ext4_ext_get_access(handle, inode, path + i); 871 if (err) 872 goto cleanup; 873 le16_add_cpu(&path[i].p_hdr->eh_entries, -m); 874 err = ext4_ext_dirty(handle, inode, path + i); 875 if (err) 876 goto cleanup; 877 } 878 879 i--; 880 } 881 882 /* insert new index */ 883 err = ext4_ext_insert_index(handle, inode, path + at, 884 le32_to_cpu(border), newblock); 885 886 cleanup: 887 if (bh) { 888 if (buffer_locked(bh)) 889 unlock_buffer(bh); 890 brelse(bh); 891 } 892 893 if (err) { 894 /* free all allocated blocks in error case */ 895 for (i = 0; i < depth; i++) { 896 if (!ablocks[i]) 897 continue; 898 ext4_free_blocks(handle, inode, ablocks[i], 1, 1); 899 } 900 } 901 kfree(ablocks); 902 903 return err; 904 } 905 906 /* 907 * ext4_ext_grow_indepth: 908 * implements tree growing procedure: 909 * - allocates new block 910 * - moves top-level data (index block or leaf) into the new block 911 * - initializes new top-level, creating index that points to the 912 * just created block 913 */ 914 static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode, 915 struct ext4_ext_path *path, 916 struct ext4_extent *newext) 917 { 918 struct ext4_ext_path *curp = path; 919 struct ext4_extent_header *neh; 920 struct ext4_extent_idx *fidx; 921 struct buffer_head *bh; 922 ext4_fsblk_t newblock; 923 int err = 0; 924 925 newblock = ext4_ext_new_meta_block(handle, inode, path, newext, &err); 926 if (newblock == 0) 927 return err; 928 929 bh = sb_getblk(inode->i_sb, newblock); 930 if (!bh) { 931 err = -EIO; 932 ext4_std_error(inode->i_sb, err); 933 return err; 934 } 935 lock_buffer(bh); 936 937 err = ext4_journal_get_create_access(handle, bh); 938 if (err) { 939 unlock_buffer(bh); 940 goto out; 941 } 942 943 /* move top-level index/leaf into new block */ 944 memmove(bh->b_data, curp->p_hdr, sizeof(EXT4_I(inode)->i_data)); 945 946 /* set size of new block */ 947 neh = ext_block_hdr(bh); 948 /* old root could have indexes or leaves 949 * so calculate e_max right way */ 950 if (ext_depth(inode)) 951 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode)); 952 else 953 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode)); 954 neh->eh_magic = EXT4_EXT_MAGIC; 955 set_buffer_uptodate(bh); 956 unlock_buffer(bh); 957 958 err = ext4_journal_dirty_metadata(handle, bh); 959 if (err) 960 goto out; 961 962 /* create index in new top-level index: num,max,pointer */ 963 err = ext4_ext_get_access(handle, inode, curp); 964 if (err) 965 goto out; 966 967 curp->p_hdr->eh_magic = EXT4_EXT_MAGIC; 968 curp->p_hdr->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode)); 969 curp->p_hdr->eh_entries = cpu_to_le16(1); 970 curp->p_idx = EXT_FIRST_INDEX(curp->p_hdr); 971 972 if (path[0].p_hdr->eh_depth) 973 curp->p_idx->ei_block = 974 EXT_FIRST_INDEX(path[0].p_hdr)->ei_block; 975 else 976 curp->p_idx->ei_block = 977 EXT_FIRST_EXTENT(path[0].p_hdr)->ee_block; 978 ext4_idx_store_pblock(curp->p_idx, newblock); 979 980 neh = ext_inode_hdr(inode); 981 fidx = EXT_FIRST_INDEX(neh); 982 ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n", 983 le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max), 984 le32_to_cpu(fidx->ei_block), idx_pblock(fidx)); 985 986 neh->eh_depth = cpu_to_le16(path->p_depth + 1); 987 err = ext4_ext_dirty(handle, inode, curp); 988 out: 989 brelse(bh); 990 991 return err; 992 } 993 994 /* 995 * ext4_ext_create_new_leaf: 996 * finds empty index and adds new leaf. 997 * if no free index is found, then it requests in-depth growing. 998 */ 999 static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode, 1000 struct ext4_ext_path *path, 1001 struct ext4_extent *newext) 1002 { 1003 struct ext4_ext_path *curp; 1004 int depth, i, err = 0; 1005 1006 repeat: 1007 i = depth = ext_depth(inode); 1008 1009 /* walk up to the tree and look for free index entry */ 1010 curp = path + depth; 1011 while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) { 1012 i--; 1013 curp--; 1014 } 1015 1016 /* we use already allocated block for index block, 1017 * so subsequent data blocks should be contiguous */ 1018 if (EXT_HAS_FREE_INDEX(curp)) { 1019 /* if we found index with free entry, then use that 1020 * entry: create all needed subtree and add new leaf */ 1021 err = ext4_ext_split(handle, inode, path, newext, i); 1022 if (err) 1023 goto out; 1024 1025 /* refill path */ 1026 ext4_ext_drop_refs(path); 1027 path = ext4_ext_find_extent(inode, 1028 (ext4_lblk_t)le32_to_cpu(newext->ee_block), 1029 path); 1030 if (IS_ERR(path)) 1031 err = PTR_ERR(path); 1032 } else { 1033 /* tree is full, time to grow in depth */ 1034 err = ext4_ext_grow_indepth(handle, inode, path, newext); 1035 if (err) 1036 goto out; 1037 1038 /* refill path */ 1039 ext4_ext_drop_refs(path); 1040 path = ext4_ext_find_extent(inode, 1041 (ext4_lblk_t)le32_to_cpu(newext->ee_block), 1042 path); 1043 if (IS_ERR(path)) { 1044 err = PTR_ERR(path); 1045 goto out; 1046 } 1047 1048 /* 1049 * only first (depth 0 -> 1) produces free space; 1050 * in all other cases we have to split the grown tree 1051 */ 1052 depth = ext_depth(inode); 1053 if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) { 1054 /* now we need to split */ 1055 goto repeat; 1056 } 1057 } 1058 1059 out: 1060 return err; 1061 } 1062 1063 /* 1064 * search the closest allocated block to the left for *logical 1065 * and returns it at @logical + it's physical address at @phys 1066 * if *logical is the smallest allocated block, the function 1067 * returns 0 at @phys 1068 * return value contains 0 (success) or error code 1069 */ 1070 int 1071 ext4_ext_search_left(struct inode *inode, struct ext4_ext_path *path, 1072 ext4_lblk_t *logical, ext4_fsblk_t *phys) 1073 { 1074 struct ext4_extent_idx *ix; 1075 struct ext4_extent *ex; 1076 int depth, ee_len; 1077 1078 BUG_ON(path == NULL); 1079 depth = path->p_depth; 1080 *phys = 0; 1081 1082 if (depth == 0 && path->p_ext == NULL) 1083 return 0; 1084 1085 /* usually extent in the path covers blocks smaller 1086 * then *logical, but it can be that extent is the 1087 * first one in the file */ 1088 1089 ex = path[depth].p_ext; 1090 ee_len = ext4_ext_get_actual_len(ex); 1091 if (*logical < le32_to_cpu(ex->ee_block)) { 1092 BUG_ON(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex); 1093 while (--depth >= 0) { 1094 ix = path[depth].p_idx; 1095 BUG_ON(ix != EXT_FIRST_INDEX(path[depth].p_hdr)); 1096 } 1097 return 0; 1098 } 1099 1100 BUG_ON(*logical < (le32_to_cpu(ex->ee_block) + ee_len)); 1101 1102 *logical = le32_to_cpu(ex->ee_block) + ee_len - 1; 1103 *phys = ext_pblock(ex) + ee_len - 1; 1104 return 0; 1105 } 1106 1107 /* 1108 * search the closest allocated block to the right for *logical 1109 * and returns it at @logical + it's physical address at @phys 1110 * if *logical is the smallest allocated block, the function 1111 * returns 0 at @phys 1112 * return value contains 0 (success) or error code 1113 */ 1114 int 1115 ext4_ext_search_right(struct inode *inode, struct ext4_ext_path *path, 1116 ext4_lblk_t *logical, ext4_fsblk_t *phys) 1117 { 1118 struct buffer_head *bh = NULL; 1119 struct ext4_extent_header *eh; 1120 struct ext4_extent_idx *ix; 1121 struct ext4_extent *ex; 1122 ext4_fsblk_t block; 1123 int depth, ee_len; 1124 1125 BUG_ON(path == NULL); 1126 depth = path->p_depth; 1127 *phys = 0; 1128 1129 if (depth == 0 && path->p_ext == NULL) 1130 return 0; 1131 1132 /* usually extent in the path covers blocks smaller 1133 * then *logical, but it can be that extent is the 1134 * first one in the file */ 1135 1136 ex = path[depth].p_ext; 1137 ee_len = ext4_ext_get_actual_len(ex); 1138 if (*logical < le32_to_cpu(ex->ee_block)) { 1139 BUG_ON(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex); 1140 while (--depth >= 0) { 1141 ix = path[depth].p_idx; 1142 BUG_ON(ix != EXT_FIRST_INDEX(path[depth].p_hdr)); 1143 } 1144 *logical = le32_to_cpu(ex->ee_block); 1145 *phys = ext_pblock(ex); 1146 return 0; 1147 } 1148 1149 BUG_ON(*logical < (le32_to_cpu(ex->ee_block) + ee_len)); 1150 1151 if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) { 1152 /* next allocated block in this leaf */ 1153 ex++; 1154 *logical = le32_to_cpu(ex->ee_block); 1155 *phys = ext_pblock(ex); 1156 return 0; 1157 } 1158 1159 /* go up and search for index to the right */ 1160 while (--depth >= 0) { 1161 ix = path[depth].p_idx; 1162 if (ix != EXT_LAST_INDEX(path[depth].p_hdr)) 1163 break; 1164 } 1165 1166 if (depth < 0) { 1167 /* we've gone up to the root and 1168 * found no index to the right */ 1169 return 0; 1170 } 1171 1172 /* we've found index to the right, let's 1173 * follow it and find the closest allocated 1174 * block to the right */ 1175 ix++; 1176 block = idx_pblock(ix); 1177 while (++depth < path->p_depth) { 1178 bh = sb_bread(inode->i_sb, block); 1179 if (bh == NULL) 1180 return -EIO; 1181 eh = ext_block_hdr(bh); 1182 if (ext4_ext_check_header(inode, eh, depth)) { 1183 put_bh(bh); 1184 return -EIO; 1185 } 1186 ix = EXT_FIRST_INDEX(eh); 1187 block = idx_pblock(ix); 1188 put_bh(bh); 1189 } 1190 1191 bh = sb_bread(inode->i_sb, block); 1192 if (bh == NULL) 1193 return -EIO; 1194 eh = ext_block_hdr(bh); 1195 if (ext4_ext_check_header(inode, eh, path->p_depth - depth)) { 1196 put_bh(bh); 1197 return -EIO; 1198 } 1199 ex = EXT_FIRST_EXTENT(eh); 1200 *logical = le32_to_cpu(ex->ee_block); 1201 *phys = ext_pblock(ex); 1202 put_bh(bh); 1203 return 0; 1204 1205 } 1206 1207 /* 1208 * ext4_ext_next_allocated_block: 1209 * returns allocated block in subsequent extent or EXT_MAX_BLOCK. 1210 * NOTE: it considers block number from index entry as 1211 * allocated block. Thus, index entries have to be consistent 1212 * with leaves. 1213 */ 1214 static ext4_lblk_t 1215 ext4_ext_next_allocated_block(struct ext4_ext_path *path) 1216 { 1217 int depth; 1218 1219 BUG_ON(path == NULL); 1220 depth = path->p_depth; 1221 1222 if (depth == 0 && path->p_ext == NULL) 1223 return EXT_MAX_BLOCK; 1224 1225 while (depth >= 0) { 1226 if (depth == path->p_depth) { 1227 /* leaf */ 1228 if (path[depth].p_ext != 1229 EXT_LAST_EXTENT(path[depth].p_hdr)) 1230 return le32_to_cpu(path[depth].p_ext[1].ee_block); 1231 } else { 1232 /* index */ 1233 if (path[depth].p_idx != 1234 EXT_LAST_INDEX(path[depth].p_hdr)) 1235 return le32_to_cpu(path[depth].p_idx[1].ei_block); 1236 } 1237 depth--; 1238 } 1239 1240 return EXT_MAX_BLOCK; 1241 } 1242 1243 /* 1244 * ext4_ext_next_leaf_block: 1245 * returns first allocated block from next leaf or EXT_MAX_BLOCK 1246 */ 1247 static ext4_lblk_t ext4_ext_next_leaf_block(struct inode *inode, 1248 struct ext4_ext_path *path) 1249 { 1250 int depth; 1251 1252 BUG_ON(path == NULL); 1253 depth = path->p_depth; 1254 1255 /* zero-tree has no leaf blocks at all */ 1256 if (depth == 0) 1257 return EXT_MAX_BLOCK; 1258 1259 /* go to index block */ 1260 depth--; 1261 1262 while (depth >= 0) { 1263 if (path[depth].p_idx != 1264 EXT_LAST_INDEX(path[depth].p_hdr)) 1265 return (ext4_lblk_t) 1266 le32_to_cpu(path[depth].p_idx[1].ei_block); 1267 depth--; 1268 } 1269 1270 return EXT_MAX_BLOCK; 1271 } 1272 1273 /* 1274 * ext4_ext_correct_indexes: 1275 * if leaf gets modified and modified extent is first in the leaf, 1276 * then we have to correct all indexes above. 1277 * TODO: do we need to correct tree in all cases? 1278 */ 1279 static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode, 1280 struct ext4_ext_path *path) 1281 { 1282 struct ext4_extent_header *eh; 1283 int depth = ext_depth(inode); 1284 struct ext4_extent *ex; 1285 __le32 border; 1286 int k, err = 0; 1287 1288 eh = path[depth].p_hdr; 1289 ex = path[depth].p_ext; 1290 BUG_ON(ex == NULL); 1291 BUG_ON(eh == NULL); 1292 1293 if (depth == 0) { 1294 /* there is no tree at all */ 1295 return 0; 1296 } 1297 1298 if (ex != EXT_FIRST_EXTENT(eh)) { 1299 /* we correct tree if first leaf got modified only */ 1300 return 0; 1301 } 1302 1303 /* 1304 * TODO: we need correction if border is smaller than current one 1305 */ 1306 k = depth - 1; 1307 border = path[depth].p_ext->ee_block; 1308 err = ext4_ext_get_access(handle, inode, path + k); 1309 if (err) 1310 return err; 1311 path[k].p_idx->ei_block = border; 1312 err = ext4_ext_dirty(handle, inode, path + k); 1313 if (err) 1314 return err; 1315 1316 while (k--) { 1317 /* change all left-side indexes */ 1318 if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr)) 1319 break; 1320 err = ext4_ext_get_access(handle, inode, path + k); 1321 if (err) 1322 break; 1323 path[k].p_idx->ei_block = border; 1324 err = ext4_ext_dirty(handle, inode, path + k); 1325 if (err) 1326 break; 1327 } 1328 1329 return err; 1330 } 1331 1332 static int 1333 ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1, 1334 struct ext4_extent *ex2) 1335 { 1336 unsigned short ext1_ee_len, ext2_ee_len, max_len; 1337 1338 /* 1339 * Make sure that either both extents are uninitialized, or 1340 * both are _not_. 1341 */ 1342 if (ext4_ext_is_uninitialized(ex1) ^ ext4_ext_is_uninitialized(ex2)) 1343 return 0; 1344 1345 if (ext4_ext_is_uninitialized(ex1)) 1346 max_len = EXT_UNINIT_MAX_LEN; 1347 else 1348 max_len = EXT_INIT_MAX_LEN; 1349 1350 ext1_ee_len = ext4_ext_get_actual_len(ex1); 1351 ext2_ee_len = ext4_ext_get_actual_len(ex2); 1352 1353 if (le32_to_cpu(ex1->ee_block) + ext1_ee_len != 1354 le32_to_cpu(ex2->ee_block)) 1355 return 0; 1356 1357 /* 1358 * To allow future support for preallocated extents to be added 1359 * as an RO_COMPAT feature, refuse to merge to extents if 1360 * this can result in the top bit of ee_len being set. 1361 */ 1362 if (ext1_ee_len + ext2_ee_len > max_len) 1363 return 0; 1364 #ifdef AGGRESSIVE_TEST 1365 if (ext1_ee_len >= 4) 1366 return 0; 1367 #endif 1368 1369 if (ext_pblock(ex1) + ext1_ee_len == ext_pblock(ex2)) 1370 return 1; 1371 return 0; 1372 } 1373 1374 /* 1375 * This function tries to merge the "ex" extent to the next extent in the tree. 1376 * It always tries to merge towards right. If you want to merge towards 1377 * left, pass "ex - 1" as argument instead of "ex". 1378 * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns 1379 * 1 if they got merged. 1380 */ 1381 int ext4_ext_try_to_merge(struct inode *inode, 1382 struct ext4_ext_path *path, 1383 struct ext4_extent *ex) 1384 { 1385 struct ext4_extent_header *eh; 1386 unsigned int depth, len; 1387 int merge_done = 0; 1388 int uninitialized = 0; 1389 1390 depth = ext_depth(inode); 1391 BUG_ON(path[depth].p_hdr == NULL); 1392 eh = path[depth].p_hdr; 1393 1394 while (ex < EXT_LAST_EXTENT(eh)) { 1395 if (!ext4_can_extents_be_merged(inode, ex, ex + 1)) 1396 break; 1397 /* merge with next extent! */ 1398 if (ext4_ext_is_uninitialized(ex)) 1399 uninitialized = 1; 1400 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex) 1401 + ext4_ext_get_actual_len(ex + 1)); 1402 if (uninitialized) 1403 ext4_ext_mark_uninitialized(ex); 1404 1405 if (ex + 1 < EXT_LAST_EXTENT(eh)) { 1406 len = (EXT_LAST_EXTENT(eh) - ex - 1) 1407 * sizeof(struct ext4_extent); 1408 memmove(ex + 1, ex + 2, len); 1409 } 1410 le16_add_cpu(&eh->eh_entries, -1); 1411 merge_done = 1; 1412 WARN_ON(eh->eh_entries == 0); 1413 if (!eh->eh_entries) 1414 ext4_error(inode->i_sb, "ext4_ext_try_to_merge", 1415 "inode#%lu, eh->eh_entries = 0!", inode->i_ino); 1416 } 1417 1418 return merge_done; 1419 } 1420 1421 /* 1422 * check if a portion of the "newext" extent overlaps with an 1423 * existing extent. 1424 * 1425 * If there is an overlap discovered, it updates the length of the newext 1426 * such that there will be no overlap, and then returns 1. 1427 * If there is no overlap found, it returns 0. 1428 */ 1429 unsigned int ext4_ext_check_overlap(struct inode *inode, 1430 struct ext4_extent *newext, 1431 struct ext4_ext_path *path) 1432 { 1433 ext4_lblk_t b1, b2; 1434 unsigned int depth, len1; 1435 unsigned int ret = 0; 1436 1437 b1 = le32_to_cpu(newext->ee_block); 1438 len1 = ext4_ext_get_actual_len(newext); 1439 depth = ext_depth(inode); 1440 if (!path[depth].p_ext) 1441 goto out; 1442 b2 = le32_to_cpu(path[depth].p_ext->ee_block); 1443 1444 /* 1445 * get the next allocated block if the extent in the path 1446 * is before the requested block(s) 1447 */ 1448 if (b2 < b1) { 1449 b2 = ext4_ext_next_allocated_block(path); 1450 if (b2 == EXT_MAX_BLOCK) 1451 goto out; 1452 } 1453 1454 /* check for wrap through zero on extent logical start block*/ 1455 if (b1 + len1 < b1) { 1456 len1 = EXT_MAX_BLOCK - b1; 1457 newext->ee_len = cpu_to_le16(len1); 1458 ret = 1; 1459 } 1460 1461 /* check for overlap */ 1462 if (b1 + len1 > b2) { 1463 newext->ee_len = cpu_to_le16(b2 - b1); 1464 ret = 1; 1465 } 1466 out: 1467 return ret; 1468 } 1469 1470 /* 1471 * ext4_ext_insert_extent: 1472 * tries to merge requsted extent into the existing extent or 1473 * inserts requested extent as new one into the tree, 1474 * creating new leaf in the no-space case. 1475 */ 1476 int ext4_ext_insert_extent(handle_t *handle, struct inode *inode, 1477 struct ext4_ext_path *path, 1478 struct ext4_extent *newext) 1479 { 1480 struct ext4_extent_header *eh; 1481 struct ext4_extent *ex, *fex; 1482 struct ext4_extent *nearex; /* nearest extent */ 1483 struct ext4_ext_path *npath = NULL; 1484 int depth, len, err; 1485 ext4_lblk_t next; 1486 unsigned uninitialized = 0; 1487 1488 BUG_ON(ext4_ext_get_actual_len(newext) == 0); 1489 depth = ext_depth(inode); 1490 ex = path[depth].p_ext; 1491 BUG_ON(path[depth].p_hdr == NULL); 1492 1493 /* try to insert block into found extent and return */ 1494 if (ex && ext4_can_extents_be_merged(inode, ex, newext)) { 1495 ext_debug("append %d block to %d:%d (from %llu)\n", 1496 ext4_ext_get_actual_len(newext), 1497 le32_to_cpu(ex->ee_block), 1498 ext4_ext_get_actual_len(ex), ext_pblock(ex)); 1499 err = ext4_ext_get_access(handle, inode, path + depth); 1500 if (err) 1501 return err; 1502 1503 /* 1504 * ext4_can_extents_be_merged should have checked that either 1505 * both extents are uninitialized, or both aren't. Thus we 1506 * need to check only one of them here. 1507 */ 1508 if (ext4_ext_is_uninitialized(ex)) 1509 uninitialized = 1; 1510 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex) 1511 + ext4_ext_get_actual_len(newext)); 1512 if (uninitialized) 1513 ext4_ext_mark_uninitialized(ex); 1514 eh = path[depth].p_hdr; 1515 nearex = ex; 1516 goto merge; 1517 } 1518 1519 repeat: 1520 depth = ext_depth(inode); 1521 eh = path[depth].p_hdr; 1522 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) 1523 goto has_space; 1524 1525 /* probably next leaf has space for us? */ 1526 fex = EXT_LAST_EXTENT(eh); 1527 next = ext4_ext_next_leaf_block(inode, path); 1528 if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block) 1529 && next != EXT_MAX_BLOCK) { 1530 ext_debug("next leaf block - %d\n", next); 1531 BUG_ON(npath != NULL); 1532 npath = ext4_ext_find_extent(inode, next, NULL); 1533 if (IS_ERR(npath)) 1534 return PTR_ERR(npath); 1535 BUG_ON(npath->p_depth != path->p_depth); 1536 eh = npath[depth].p_hdr; 1537 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) { 1538 ext_debug("next leaf isnt full(%d)\n", 1539 le16_to_cpu(eh->eh_entries)); 1540 path = npath; 1541 goto repeat; 1542 } 1543 ext_debug("next leaf has no free space(%d,%d)\n", 1544 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max)); 1545 } 1546 1547 /* 1548 * There is no free space in the found leaf. 1549 * We're gonna add a new leaf in the tree. 1550 */ 1551 err = ext4_ext_create_new_leaf(handle, inode, path, newext); 1552 if (err) 1553 goto cleanup; 1554 depth = ext_depth(inode); 1555 eh = path[depth].p_hdr; 1556 1557 has_space: 1558 nearex = path[depth].p_ext; 1559 1560 err = ext4_ext_get_access(handle, inode, path + depth); 1561 if (err) 1562 goto cleanup; 1563 1564 if (!nearex) { 1565 /* there is no extent in this leaf, create first one */ 1566 ext_debug("first extent in the leaf: %d:%llu:%d\n", 1567 le32_to_cpu(newext->ee_block), 1568 ext_pblock(newext), 1569 ext4_ext_get_actual_len(newext)); 1570 path[depth].p_ext = EXT_FIRST_EXTENT(eh); 1571 } else if (le32_to_cpu(newext->ee_block) 1572 > le32_to_cpu(nearex->ee_block)) { 1573 /* BUG_ON(newext->ee_block == nearex->ee_block); */ 1574 if (nearex != EXT_LAST_EXTENT(eh)) { 1575 len = EXT_MAX_EXTENT(eh) - nearex; 1576 len = (len - 1) * sizeof(struct ext4_extent); 1577 len = len < 0 ? 0 : len; 1578 ext_debug("insert %d:%llu:%d after: nearest 0x%p, " 1579 "move %d from 0x%p to 0x%p\n", 1580 le32_to_cpu(newext->ee_block), 1581 ext_pblock(newext), 1582 ext4_ext_get_actual_len(newext), 1583 nearex, len, nearex + 1, nearex + 2); 1584 memmove(nearex + 2, nearex + 1, len); 1585 } 1586 path[depth].p_ext = nearex + 1; 1587 } else { 1588 BUG_ON(newext->ee_block == nearex->ee_block); 1589 len = (EXT_MAX_EXTENT(eh) - nearex) * sizeof(struct ext4_extent); 1590 len = len < 0 ? 0 : len; 1591 ext_debug("insert %d:%llu:%d before: nearest 0x%p, " 1592 "move %d from 0x%p to 0x%p\n", 1593 le32_to_cpu(newext->ee_block), 1594 ext_pblock(newext), 1595 ext4_ext_get_actual_len(newext), 1596 nearex, len, nearex + 1, nearex + 2); 1597 memmove(nearex + 1, nearex, len); 1598 path[depth].p_ext = nearex; 1599 } 1600 1601 le16_add_cpu(&eh->eh_entries, 1); 1602 nearex = path[depth].p_ext; 1603 nearex->ee_block = newext->ee_block; 1604 ext4_ext_store_pblock(nearex, ext_pblock(newext)); 1605 nearex->ee_len = newext->ee_len; 1606 1607 merge: 1608 /* try to merge extents to the right */ 1609 ext4_ext_try_to_merge(inode, path, nearex); 1610 1611 /* try to merge extents to the left */ 1612 1613 /* time to correct all indexes above */ 1614 err = ext4_ext_correct_indexes(handle, inode, path); 1615 if (err) 1616 goto cleanup; 1617 1618 err = ext4_ext_dirty(handle, inode, path + depth); 1619 1620 cleanup: 1621 if (npath) { 1622 ext4_ext_drop_refs(npath); 1623 kfree(npath); 1624 } 1625 ext4_ext_tree_changed(inode); 1626 ext4_ext_invalidate_cache(inode); 1627 return err; 1628 } 1629 1630 int ext4_ext_walk_space(struct inode *inode, ext4_lblk_t block, 1631 ext4_lblk_t num, ext_prepare_callback func, 1632 void *cbdata) 1633 { 1634 struct ext4_ext_path *path = NULL; 1635 struct ext4_ext_cache cbex; 1636 struct ext4_extent *ex; 1637 ext4_lblk_t next, start = 0, end = 0; 1638 ext4_lblk_t last = block + num; 1639 int depth, exists, err = 0; 1640 1641 BUG_ON(func == NULL); 1642 BUG_ON(inode == NULL); 1643 1644 while (block < last && block != EXT_MAX_BLOCK) { 1645 num = last - block; 1646 /* find extent for this block */ 1647 path = ext4_ext_find_extent(inode, block, path); 1648 if (IS_ERR(path)) { 1649 err = PTR_ERR(path); 1650 path = NULL; 1651 break; 1652 } 1653 1654 depth = ext_depth(inode); 1655 BUG_ON(path[depth].p_hdr == NULL); 1656 ex = path[depth].p_ext; 1657 next = ext4_ext_next_allocated_block(path); 1658 1659 exists = 0; 1660 if (!ex) { 1661 /* there is no extent yet, so try to allocate 1662 * all requested space */ 1663 start = block; 1664 end = block + num; 1665 } else if (le32_to_cpu(ex->ee_block) > block) { 1666 /* need to allocate space before found extent */ 1667 start = block; 1668 end = le32_to_cpu(ex->ee_block); 1669 if (block + num < end) 1670 end = block + num; 1671 } else if (block >= le32_to_cpu(ex->ee_block) 1672 + ext4_ext_get_actual_len(ex)) { 1673 /* need to allocate space after found extent */ 1674 start = block; 1675 end = block + num; 1676 if (end >= next) 1677 end = next; 1678 } else if (block >= le32_to_cpu(ex->ee_block)) { 1679 /* 1680 * some part of requested space is covered 1681 * by found extent 1682 */ 1683 start = block; 1684 end = le32_to_cpu(ex->ee_block) 1685 + ext4_ext_get_actual_len(ex); 1686 if (block + num < end) 1687 end = block + num; 1688 exists = 1; 1689 } else { 1690 BUG(); 1691 } 1692 BUG_ON(end <= start); 1693 1694 if (!exists) { 1695 cbex.ec_block = start; 1696 cbex.ec_len = end - start; 1697 cbex.ec_start = 0; 1698 cbex.ec_type = EXT4_EXT_CACHE_GAP; 1699 } else { 1700 cbex.ec_block = le32_to_cpu(ex->ee_block); 1701 cbex.ec_len = ext4_ext_get_actual_len(ex); 1702 cbex.ec_start = ext_pblock(ex); 1703 cbex.ec_type = EXT4_EXT_CACHE_EXTENT; 1704 } 1705 1706 BUG_ON(cbex.ec_len == 0); 1707 err = func(inode, path, &cbex, ex, cbdata); 1708 ext4_ext_drop_refs(path); 1709 1710 if (err < 0) 1711 break; 1712 1713 if (err == EXT_REPEAT) 1714 continue; 1715 else if (err == EXT_BREAK) { 1716 err = 0; 1717 break; 1718 } 1719 1720 if (ext_depth(inode) != depth) { 1721 /* depth was changed. we have to realloc path */ 1722 kfree(path); 1723 path = NULL; 1724 } 1725 1726 block = cbex.ec_block + cbex.ec_len; 1727 } 1728 1729 if (path) { 1730 ext4_ext_drop_refs(path); 1731 kfree(path); 1732 } 1733 1734 return err; 1735 } 1736 1737 static void 1738 ext4_ext_put_in_cache(struct inode *inode, ext4_lblk_t block, 1739 __u32 len, ext4_fsblk_t start, int type) 1740 { 1741 struct ext4_ext_cache *cex; 1742 BUG_ON(len == 0); 1743 cex = &EXT4_I(inode)->i_cached_extent; 1744 cex->ec_type = type; 1745 cex->ec_block = block; 1746 cex->ec_len = len; 1747 cex->ec_start = start; 1748 } 1749 1750 /* 1751 * ext4_ext_put_gap_in_cache: 1752 * calculate boundaries of the gap that the requested block fits into 1753 * and cache this gap 1754 */ 1755 static void 1756 ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path, 1757 ext4_lblk_t block) 1758 { 1759 int depth = ext_depth(inode); 1760 unsigned long len; 1761 ext4_lblk_t lblock; 1762 struct ext4_extent *ex; 1763 1764 ex = path[depth].p_ext; 1765 if (ex == NULL) { 1766 /* there is no extent yet, so gap is [0;-] */ 1767 lblock = 0; 1768 len = EXT_MAX_BLOCK; 1769 ext_debug("cache gap(whole file):"); 1770 } else if (block < le32_to_cpu(ex->ee_block)) { 1771 lblock = block; 1772 len = le32_to_cpu(ex->ee_block) - block; 1773 ext_debug("cache gap(before): %u [%u:%u]", 1774 block, 1775 le32_to_cpu(ex->ee_block), 1776 ext4_ext_get_actual_len(ex)); 1777 } else if (block >= le32_to_cpu(ex->ee_block) 1778 + ext4_ext_get_actual_len(ex)) { 1779 ext4_lblk_t next; 1780 lblock = le32_to_cpu(ex->ee_block) 1781 + ext4_ext_get_actual_len(ex); 1782 1783 next = ext4_ext_next_allocated_block(path); 1784 ext_debug("cache gap(after): [%u:%u] %u", 1785 le32_to_cpu(ex->ee_block), 1786 ext4_ext_get_actual_len(ex), 1787 block); 1788 BUG_ON(next == lblock); 1789 len = next - lblock; 1790 } else { 1791 lblock = len = 0; 1792 BUG(); 1793 } 1794 1795 ext_debug(" -> %u:%lu\n", lblock, len); 1796 ext4_ext_put_in_cache(inode, lblock, len, 0, EXT4_EXT_CACHE_GAP); 1797 } 1798 1799 static int 1800 ext4_ext_in_cache(struct inode *inode, ext4_lblk_t block, 1801 struct ext4_extent *ex) 1802 { 1803 struct ext4_ext_cache *cex; 1804 1805 cex = &EXT4_I(inode)->i_cached_extent; 1806 1807 /* has cache valid data? */ 1808 if (cex->ec_type == EXT4_EXT_CACHE_NO) 1809 return EXT4_EXT_CACHE_NO; 1810 1811 BUG_ON(cex->ec_type != EXT4_EXT_CACHE_GAP && 1812 cex->ec_type != EXT4_EXT_CACHE_EXTENT); 1813 if (block >= cex->ec_block && block < cex->ec_block + cex->ec_len) { 1814 ex->ee_block = cpu_to_le32(cex->ec_block); 1815 ext4_ext_store_pblock(ex, cex->ec_start); 1816 ex->ee_len = cpu_to_le16(cex->ec_len); 1817 ext_debug("%u cached by %u:%u:%llu\n", 1818 block, 1819 cex->ec_block, cex->ec_len, cex->ec_start); 1820 return cex->ec_type; 1821 } 1822 1823 /* not in cache */ 1824 return EXT4_EXT_CACHE_NO; 1825 } 1826 1827 /* 1828 * ext4_ext_rm_idx: 1829 * removes index from the index block. 1830 * It's used in truncate case only, thus all requests are for 1831 * last index in the block only. 1832 */ 1833 static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode, 1834 struct ext4_ext_path *path) 1835 { 1836 struct buffer_head *bh; 1837 int err; 1838 ext4_fsblk_t leaf; 1839 1840 /* free index block */ 1841 path--; 1842 leaf = idx_pblock(path->p_idx); 1843 BUG_ON(path->p_hdr->eh_entries == 0); 1844 err = ext4_ext_get_access(handle, inode, path); 1845 if (err) 1846 return err; 1847 le16_add_cpu(&path->p_hdr->eh_entries, -1); 1848 err = ext4_ext_dirty(handle, inode, path); 1849 if (err) 1850 return err; 1851 ext_debug("index is empty, remove it, free block %llu\n", leaf); 1852 bh = sb_find_get_block(inode->i_sb, leaf); 1853 ext4_forget(handle, 1, inode, bh, leaf); 1854 ext4_free_blocks(handle, inode, leaf, 1, 1); 1855 return err; 1856 } 1857 1858 /* 1859 * ext4_ext_calc_credits_for_single_extent: 1860 * This routine returns max. credits that needed to insert an extent 1861 * to the extent tree. 1862 * When pass the actual path, the caller should calculate credits 1863 * under i_data_sem. 1864 */ 1865 int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks, 1866 struct ext4_ext_path *path) 1867 { 1868 if (path) { 1869 int depth = ext_depth(inode); 1870 int ret = 0; 1871 1872 /* probably there is space in leaf? */ 1873 if (le16_to_cpu(path[depth].p_hdr->eh_entries) 1874 < le16_to_cpu(path[depth].p_hdr->eh_max)) { 1875 1876 /* 1877 * There are some space in the leaf tree, no 1878 * need to account for leaf block credit 1879 * 1880 * bitmaps and block group descriptor blocks 1881 * and other metadat blocks still need to be 1882 * accounted. 1883 */ 1884 /* 1 bitmap, 1 block group descriptor */ 1885 ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb); 1886 } 1887 } 1888 1889 return ext4_chunk_trans_blocks(inode, nrblocks); 1890 } 1891 1892 /* 1893 * How many index/leaf blocks need to change/allocate to modify nrblocks? 1894 * 1895 * if nrblocks are fit in a single extent (chunk flag is 1), then 1896 * in the worse case, each tree level index/leaf need to be changed 1897 * if the tree split due to insert a new extent, then the old tree 1898 * index/leaf need to be updated too 1899 * 1900 * If the nrblocks are discontiguous, they could cause 1901 * the whole tree split more than once, but this is really rare. 1902 */ 1903 int ext4_ext_index_trans_blocks(struct inode *inode, int nrblocks, int chunk) 1904 { 1905 int index; 1906 int depth = ext_depth(inode); 1907 1908 if (chunk) 1909 index = depth * 2; 1910 else 1911 index = depth * 3; 1912 1913 return index; 1914 } 1915 1916 static int ext4_remove_blocks(handle_t *handle, struct inode *inode, 1917 struct ext4_extent *ex, 1918 ext4_lblk_t from, ext4_lblk_t to) 1919 { 1920 struct buffer_head *bh; 1921 unsigned short ee_len = ext4_ext_get_actual_len(ex); 1922 int i, metadata = 0; 1923 1924 if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) 1925 metadata = 1; 1926 #ifdef EXTENTS_STATS 1927 { 1928 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 1929 spin_lock(&sbi->s_ext_stats_lock); 1930 sbi->s_ext_blocks += ee_len; 1931 sbi->s_ext_extents++; 1932 if (ee_len < sbi->s_ext_min) 1933 sbi->s_ext_min = ee_len; 1934 if (ee_len > sbi->s_ext_max) 1935 sbi->s_ext_max = ee_len; 1936 if (ext_depth(inode) > sbi->s_depth_max) 1937 sbi->s_depth_max = ext_depth(inode); 1938 spin_unlock(&sbi->s_ext_stats_lock); 1939 } 1940 #endif 1941 if (from >= le32_to_cpu(ex->ee_block) 1942 && to == le32_to_cpu(ex->ee_block) + ee_len - 1) { 1943 /* tail removal */ 1944 ext4_lblk_t num; 1945 ext4_fsblk_t start; 1946 1947 num = le32_to_cpu(ex->ee_block) + ee_len - from; 1948 start = ext_pblock(ex) + ee_len - num; 1949 ext_debug("free last %u blocks starting %llu\n", num, start); 1950 for (i = 0; i < num; i++) { 1951 bh = sb_find_get_block(inode->i_sb, start + i); 1952 ext4_forget(handle, 0, inode, bh, start + i); 1953 } 1954 ext4_free_blocks(handle, inode, start, num, metadata); 1955 } else if (from == le32_to_cpu(ex->ee_block) 1956 && to <= le32_to_cpu(ex->ee_block) + ee_len - 1) { 1957 printk(KERN_INFO "strange request: removal %u-%u from %u:%u\n", 1958 from, to, le32_to_cpu(ex->ee_block), ee_len); 1959 } else { 1960 printk(KERN_INFO "strange request: removal(2) " 1961 "%u-%u from %u:%u\n", 1962 from, to, le32_to_cpu(ex->ee_block), ee_len); 1963 } 1964 return 0; 1965 } 1966 1967 static int 1968 ext4_ext_rm_leaf(handle_t *handle, struct inode *inode, 1969 struct ext4_ext_path *path, ext4_lblk_t start) 1970 { 1971 int err = 0, correct_index = 0; 1972 int depth = ext_depth(inode), credits; 1973 struct ext4_extent_header *eh; 1974 ext4_lblk_t a, b, block; 1975 unsigned num; 1976 ext4_lblk_t ex_ee_block; 1977 unsigned short ex_ee_len; 1978 unsigned uninitialized = 0; 1979 struct ext4_extent *ex; 1980 1981 /* the header must be checked already in ext4_ext_remove_space() */ 1982 ext_debug("truncate since %u in leaf\n", start); 1983 if (!path[depth].p_hdr) 1984 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh); 1985 eh = path[depth].p_hdr; 1986 BUG_ON(eh == NULL); 1987 1988 /* find where to start removing */ 1989 ex = EXT_LAST_EXTENT(eh); 1990 1991 ex_ee_block = le32_to_cpu(ex->ee_block); 1992 if (ext4_ext_is_uninitialized(ex)) 1993 uninitialized = 1; 1994 ex_ee_len = ext4_ext_get_actual_len(ex); 1995 1996 while (ex >= EXT_FIRST_EXTENT(eh) && 1997 ex_ee_block + ex_ee_len > start) { 1998 ext_debug("remove ext %lu:%u\n", ex_ee_block, ex_ee_len); 1999 path[depth].p_ext = ex; 2000 2001 a = ex_ee_block > start ? ex_ee_block : start; 2002 b = ex_ee_block + ex_ee_len - 1 < EXT_MAX_BLOCK ? 2003 ex_ee_block + ex_ee_len - 1 : EXT_MAX_BLOCK; 2004 2005 ext_debug(" border %u:%u\n", a, b); 2006 2007 if (a != ex_ee_block && b != ex_ee_block + ex_ee_len - 1) { 2008 block = 0; 2009 num = 0; 2010 BUG(); 2011 } else if (a != ex_ee_block) { 2012 /* remove tail of the extent */ 2013 block = ex_ee_block; 2014 num = a - block; 2015 } else if (b != ex_ee_block + ex_ee_len - 1) { 2016 /* remove head of the extent */ 2017 block = a; 2018 num = b - a; 2019 /* there is no "make a hole" API yet */ 2020 BUG(); 2021 } else { 2022 /* remove whole extent: excellent! */ 2023 block = ex_ee_block; 2024 num = 0; 2025 BUG_ON(a != ex_ee_block); 2026 BUG_ON(b != ex_ee_block + ex_ee_len - 1); 2027 } 2028 2029 /* 2030 * 3 for leaf, sb, and inode plus 2 (bmap and group 2031 * descriptor) for each block group; assume two block 2032 * groups plus ex_ee_len/blocks_per_block_group for 2033 * the worst case 2034 */ 2035 credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb)); 2036 if (ex == EXT_FIRST_EXTENT(eh)) { 2037 correct_index = 1; 2038 credits += (ext_depth(inode)) + 1; 2039 } 2040 credits += 2 * EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb); 2041 2042 err = ext4_ext_journal_restart(handle, credits); 2043 if (err) 2044 goto out; 2045 2046 err = ext4_ext_get_access(handle, inode, path + depth); 2047 if (err) 2048 goto out; 2049 2050 err = ext4_remove_blocks(handle, inode, ex, a, b); 2051 if (err) 2052 goto out; 2053 2054 if (num == 0) { 2055 /* this extent is removed; mark slot entirely unused */ 2056 ext4_ext_store_pblock(ex, 0); 2057 le16_add_cpu(&eh->eh_entries, -1); 2058 } 2059 2060 ex->ee_block = cpu_to_le32(block); 2061 ex->ee_len = cpu_to_le16(num); 2062 /* 2063 * Do not mark uninitialized if all the blocks in the 2064 * extent have been removed. 2065 */ 2066 if (uninitialized && num) 2067 ext4_ext_mark_uninitialized(ex); 2068 2069 err = ext4_ext_dirty(handle, inode, path + depth); 2070 if (err) 2071 goto out; 2072 2073 ext_debug("new extent: %u:%u:%llu\n", block, num, 2074 ext_pblock(ex)); 2075 ex--; 2076 ex_ee_block = le32_to_cpu(ex->ee_block); 2077 ex_ee_len = ext4_ext_get_actual_len(ex); 2078 } 2079 2080 if (correct_index && eh->eh_entries) 2081 err = ext4_ext_correct_indexes(handle, inode, path); 2082 2083 /* if this leaf is free, then we should 2084 * remove it from index block above */ 2085 if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL) 2086 err = ext4_ext_rm_idx(handle, inode, path + depth); 2087 2088 out: 2089 return err; 2090 } 2091 2092 /* 2093 * ext4_ext_more_to_rm: 2094 * returns 1 if current index has to be freed (even partial) 2095 */ 2096 static int 2097 ext4_ext_more_to_rm(struct ext4_ext_path *path) 2098 { 2099 BUG_ON(path->p_idx == NULL); 2100 2101 if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr)) 2102 return 0; 2103 2104 /* 2105 * if truncate on deeper level happened, it wasn't partial, 2106 * so we have to consider current index for truncation 2107 */ 2108 if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block) 2109 return 0; 2110 return 1; 2111 } 2112 2113 static int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start) 2114 { 2115 struct super_block *sb = inode->i_sb; 2116 int depth = ext_depth(inode); 2117 struct ext4_ext_path *path; 2118 handle_t *handle; 2119 int i = 0, err = 0; 2120 2121 ext_debug("truncate since %u\n", start); 2122 2123 /* probably first extent we're gonna free will be last in block */ 2124 handle = ext4_journal_start(inode, depth + 1); 2125 if (IS_ERR(handle)) 2126 return PTR_ERR(handle); 2127 2128 ext4_ext_invalidate_cache(inode); 2129 2130 /* 2131 * We start scanning from right side, freeing all the blocks 2132 * after i_size and walking into the tree depth-wise. 2133 */ 2134 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1), GFP_NOFS); 2135 if (path == NULL) { 2136 ext4_journal_stop(handle); 2137 return -ENOMEM; 2138 } 2139 path[0].p_hdr = ext_inode_hdr(inode); 2140 if (ext4_ext_check_header(inode, path[0].p_hdr, depth)) { 2141 err = -EIO; 2142 goto out; 2143 } 2144 path[0].p_depth = depth; 2145 2146 while (i >= 0 && err == 0) { 2147 if (i == depth) { 2148 /* this is leaf block */ 2149 err = ext4_ext_rm_leaf(handle, inode, path, start); 2150 /* root level has p_bh == NULL, brelse() eats this */ 2151 brelse(path[i].p_bh); 2152 path[i].p_bh = NULL; 2153 i--; 2154 continue; 2155 } 2156 2157 /* this is index block */ 2158 if (!path[i].p_hdr) { 2159 ext_debug("initialize header\n"); 2160 path[i].p_hdr = ext_block_hdr(path[i].p_bh); 2161 } 2162 2163 if (!path[i].p_idx) { 2164 /* this level hasn't been touched yet */ 2165 path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr); 2166 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1; 2167 ext_debug("init index ptr: hdr 0x%p, num %d\n", 2168 path[i].p_hdr, 2169 le16_to_cpu(path[i].p_hdr->eh_entries)); 2170 } else { 2171 /* we were already here, see at next index */ 2172 path[i].p_idx--; 2173 } 2174 2175 ext_debug("level %d - index, first 0x%p, cur 0x%p\n", 2176 i, EXT_FIRST_INDEX(path[i].p_hdr), 2177 path[i].p_idx); 2178 if (ext4_ext_more_to_rm(path + i)) { 2179 struct buffer_head *bh; 2180 /* go to the next level */ 2181 ext_debug("move to level %d (block %llu)\n", 2182 i + 1, idx_pblock(path[i].p_idx)); 2183 memset(path + i + 1, 0, sizeof(*path)); 2184 bh = sb_bread(sb, idx_pblock(path[i].p_idx)); 2185 if (!bh) { 2186 /* should we reset i_size? */ 2187 err = -EIO; 2188 break; 2189 } 2190 if (WARN_ON(i + 1 > depth)) { 2191 err = -EIO; 2192 break; 2193 } 2194 if (ext4_ext_check_header(inode, ext_block_hdr(bh), 2195 depth - i - 1)) { 2196 err = -EIO; 2197 break; 2198 } 2199 path[i + 1].p_bh = bh; 2200 2201 /* save actual number of indexes since this 2202 * number is changed at the next iteration */ 2203 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries); 2204 i++; 2205 } else { 2206 /* we finished processing this index, go up */ 2207 if (path[i].p_hdr->eh_entries == 0 && i > 0) { 2208 /* index is empty, remove it; 2209 * handle must be already prepared by the 2210 * truncatei_leaf() */ 2211 err = ext4_ext_rm_idx(handle, inode, path + i); 2212 } 2213 /* root level has p_bh == NULL, brelse() eats this */ 2214 brelse(path[i].p_bh); 2215 path[i].p_bh = NULL; 2216 i--; 2217 ext_debug("return to level %d\n", i); 2218 } 2219 } 2220 2221 /* TODO: flexible tree reduction should be here */ 2222 if (path->p_hdr->eh_entries == 0) { 2223 /* 2224 * truncate to zero freed all the tree, 2225 * so we need to correct eh_depth 2226 */ 2227 err = ext4_ext_get_access(handle, inode, path); 2228 if (err == 0) { 2229 ext_inode_hdr(inode)->eh_depth = 0; 2230 ext_inode_hdr(inode)->eh_max = 2231 cpu_to_le16(ext4_ext_space_root(inode)); 2232 err = ext4_ext_dirty(handle, inode, path); 2233 } 2234 } 2235 out: 2236 ext4_ext_tree_changed(inode); 2237 ext4_ext_drop_refs(path); 2238 kfree(path); 2239 ext4_journal_stop(handle); 2240 2241 return err; 2242 } 2243 2244 /* 2245 * called at mount time 2246 */ 2247 void ext4_ext_init(struct super_block *sb) 2248 { 2249 /* 2250 * possible initialization would be here 2251 */ 2252 2253 if (test_opt(sb, EXTENTS)) { 2254 printk(KERN_INFO "EXT4-fs: file extents enabled"); 2255 #ifdef AGGRESSIVE_TEST 2256 printk(", aggressive tests"); 2257 #endif 2258 #ifdef CHECK_BINSEARCH 2259 printk(", check binsearch"); 2260 #endif 2261 #ifdef EXTENTS_STATS 2262 printk(", stats"); 2263 #endif 2264 printk("\n"); 2265 #ifdef EXTENTS_STATS 2266 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock); 2267 EXT4_SB(sb)->s_ext_min = 1 << 30; 2268 EXT4_SB(sb)->s_ext_max = 0; 2269 #endif 2270 } 2271 } 2272 2273 /* 2274 * called at umount time 2275 */ 2276 void ext4_ext_release(struct super_block *sb) 2277 { 2278 if (!test_opt(sb, EXTENTS)) 2279 return; 2280 2281 #ifdef EXTENTS_STATS 2282 if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) { 2283 struct ext4_sb_info *sbi = EXT4_SB(sb); 2284 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n", 2285 sbi->s_ext_blocks, sbi->s_ext_extents, 2286 sbi->s_ext_blocks / sbi->s_ext_extents); 2287 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n", 2288 sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max); 2289 } 2290 #endif 2291 } 2292 2293 static void bi_complete(struct bio *bio, int error) 2294 { 2295 complete((struct completion *)bio->bi_private); 2296 } 2297 2298 /* FIXME!! we need to try to merge to left or right after zero-out */ 2299 static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex) 2300 { 2301 int ret = -EIO; 2302 struct bio *bio; 2303 int blkbits, blocksize; 2304 sector_t ee_pblock; 2305 struct completion event; 2306 unsigned int ee_len, len, done, offset; 2307 2308 2309 blkbits = inode->i_blkbits; 2310 blocksize = inode->i_sb->s_blocksize; 2311 ee_len = ext4_ext_get_actual_len(ex); 2312 ee_pblock = ext_pblock(ex); 2313 2314 /* convert ee_pblock to 512 byte sectors */ 2315 ee_pblock = ee_pblock << (blkbits - 9); 2316 2317 while (ee_len > 0) { 2318 2319 if (ee_len > BIO_MAX_PAGES) 2320 len = BIO_MAX_PAGES; 2321 else 2322 len = ee_len; 2323 2324 bio = bio_alloc(GFP_NOIO, len); 2325 if (!bio) 2326 return -ENOMEM; 2327 bio->bi_sector = ee_pblock; 2328 bio->bi_bdev = inode->i_sb->s_bdev; 2329 2330 done = 0; 2331 offset = 0; 2332 while (done < len) { 2333 ret = bio_add_page(bio, ZERO_PAGE(0), 2334 blocksize, offset); 2335 if (ret != blocksize) { 2336 /* 2337 * We can't add any more pages because of 2338 * hardware limitations. Start a new bio. 2339 */ 2340 break; 2341 } 2342 done++; 2343 offset += blocksize; 2344 if (offset >= PAGE_CACHE_SIZE) 2345 offset = 0; 2346 } 2347 2348 init_completion(&event); 2349 bio->bi_private = &event; 2350 bio->bi_end_io = bi_complete; 2351 submit_bio(WRITE, bio); 2352 wait_for_completion(&event); 2353 2354 if (test_bit(BIO_UPTODATE, &bio->bi_flags)) 2355 ret = 0; 2356 else { 2357 ret = -EIO; 2358 break; 2359 } 2360 bio_put(bio); 2361 ee_len -= done; 2362 ee_pblock += done << (blkbits - 9); 2363 } 2364 return ret; 2365 } 2366 2367 #define EXT4_EXT_ZERO_LEN 7 2368 2369 /* 2370 * This function is called by ext4_ext_get_blocks() if someone tries to write 2371 * to an uninitialized extent. It may result in splitting the uninitialized 2372 * extent into multiple extents (upto three - one initialized and two 2373 * uninitialized). 2374 * There are three possibilities: 2375 * a> There is no split required: Entire extent should be initialized 2376 * b> Splits in two extents: Write is happening at either end of the extent 2377 * c> Splits in three extents: Somone is writing in middle of the extent 2378 */ 2379 static int ext4_ext_convert_to_initialized(handle_t *handle, 2380 struct inode *inode, 2381 struct ext4_ext_path *path, 2382 ext4_lblk_t iblock, 2383 unsigned long max_blocks) 2384 { 2385 struct ext4_extent *ex, newex, orig_ex; 2386 struct ext4_extent *ex1 = NULL; 2387 struct ext4_extent *ex2 = NULL; 2388 struct ext4_extent *ex3 = NULL; 2389 struct ext4_extent_header *eh; 2390 ext4_lblk_t ee_block; 2391 unsigned int allocated, ee_len, depth; 2392 ext4_fsblk_t newblock; 2393 int err = 0; 2394 int ret = 0; 2395 2396 depth = ext_depth(inode); 2397 eh = path[depth].p_hdr; 2398 ex = path[depth].p_ext; 2399 ee_block = le32_to_cpu(ex->ee_block); 2400 ee_len = ext4_ext_get_actual_len(ex); 2401 allocated = ee_len - (iblock - ee_block); 2402 newblock = iblock - ee_block + ext_pblock(ex); 2403 ex2 = ex; 2404 orig_ex.ee_block = ex->ee_block; 2405 orig_ex.ee_len = cpu_to_le16(ee_len); 2406 ext4_ext_store_pblock(&orig_ex, ext_pblock(ex)); 2407 2408 err = ext4_ext_get_access(handle, inode, path + depth); 2409 if (err) 2410 goto out; 2411 /* If extent has less than 2*EXT4_EXT_ZERO_LEN zerout directly */ 2412 if (ee_len <= 2*EXT4_EXT_ZERO_LEN) { 2413 err = ext4_ext_zeroout(inode, &orig_ex); 2414 if (err) 2415 goto fix_extent_len; 2416 /* update the extent length and mark as initialized */ 2417 ex->ee_block = orig_ex.ee_block; 2418 ex->ee_len = orig_ex.ee_len; 2419 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2420 ext4_ext_dirty(handle, inode, path + depth); 2421 /* zeroed the full extent */ 2422 return allocated; 2423 } 2424 2425 /* ex1: ee_block to iblock - 1 : uninitialized */ 2426 if (iblock > ee_block) { 2427 ex1 = ex; 2428 ex1->ee_len = cpu_to_le16(iblock - ee_block); 2429 ext4_ext_mark_uninitialized(ex1); 2430 ex2 = &newex; 2431 } 2432 /* 2433 * for sanity, update the length of the ex2 extent before 2434 * we insert ex3, if ex1 is NULL. This is to avoid temporary 2435 * overlap of blocks. 2436 */ 2437 if (!ex1 && allocated > max_blocks) 2438 ex2->ee_len = cpu_to_le16(max_blocks); 2439 /* ex3: to ee_block + ee_len : uninitialised */ 2440 if (allocated > max_blocks) { 2441 unsigned int newdepth; 2442 /* If extent has less than EXT4_EXT_ZERO_LEN zerout directly */ 2443 if (allocated <= EXT4_EXT_ZERO_LEN) { 2444 /* 2445 * iblock == ee_block is handled by the zerouout 2446 * at the beginning. 2447 * Mark first half uninitialized. 2448 * Mark second half initialized and zero out the 2449 * initialized extent 2450 */ 2451 ex->ee_block = orig_ex.ee_block; 2452 ex->ee_len = cpu_to_le16(ee_len - allocated); 2453 ext4_ext_mark_uninitialized(ex); 2454 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2455 ext4_ext_dirty(handle, inode, path + depth); 2456 2457 ex3 = &newex; 2458 ex3->ee_block = cpu_to_le32(iblock); 2459 ext4_ext_store_pblock(ex3, newblock); 2460 ex3->ee_len = cpu_to_le16(allocated); 2461 err = ext4_ext_insert_extent(handle, inode, path, ex3); 2462 if (err == -ENOSPC) { 2463 err = ext4_ext_zeroout(inode, &orig_ex); 2464 if (err) 2465 goto fix_extent_len; 2466 ex->ee_block = orig_ex.ee_block; 2467 ex->ee_len = orig_ex.ee_len; 2468 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2469 ext4_ext_dirty(handle, inode, path + depth); 2470 /* blocks available from iblock */ 2471 return allocated; 2472 2473 } else if (err) 2474 goto fix_extent_len; 2475 2476 /* 2477 * We need to zero out the second half because 2478 * an fallocate request can update file size and 2479 * converting the second half to initialized extent 2480 * implies that we can leak some junk data to user 2481 * space. 2482 */ 2483 err = ext4_ext_zeroout(inode, ex3); 2484 if (err) { 2485 /* 2486 * We should actually mark the 2487 * second half as uninit and return error 2488 * Insert would have changed the extent 2489 */ 2490 depth = ext_depth(inode); 2491 ext4_ext_drop_refs(path); 2492 path = ext4_ext_find_extent(inode, 2493 iblock, path); 2494 if (IS_ERR(path)) { 2495 err = PTR_ERR(path); 2496 return err; 2497 } 2498 /* get the second half extent details */ 2499 ex = path[depth].p_ext; 2500 err = ext4_ext_get_access(handle, inode, 2501 path + depth); 2502 if (err) 2503 return err; 2504 ext4_ext_mark_uninitialized(ex); 2505 ext4_ext_dirty(handle, inode, path + depth); 2506 return err; 2507 } 2508 2509 /* zeroed the second half */ 2510 return allocated; 2511 } 2512 ex3 = &newex; 2513 ex3->ee_block = cpu_to_le32(iblock + max_blocks); 2514 ext4_ext_store_pblock(ex3, newblock + max_blocks); 2515 ex3->ee_len = cpu_to_le16(allocated - max_blocks); 2516 ext4_ext_mark_uninitialized(ex3); 2517 err = ext4_ext_insert_extent(handle, inode, path, ex3); 2518 if (err == -ENOSPC) { 2519 err = ext4_ext_zeroout(inode, &orig_ex); 2520 if (err) 2521 goto fix_extent_len; 2522 /* update the extent length and mark as initialized */ 2523 ex->ee_block = orig_ex.ee_block; 2524 ex->ee_len = orig_ex.ee_len; 2525 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2526 ext4_ext_dirty(handle, inode, path + depth); 2527 /* zeroed the full extent */ 2528 /* blocks available from iblock */ 2529 return allocated; 2530 2531 } else if (err) 2532 goto fix_extent_len; 2533 /* 2534 * The depth, and hence eh & ex might change 2535 * as part of the insert above. 2536 */ 2537 newdepth = ext_depth(inode); 2538 /* 2539 * update the extent length after successfull insert of the 2540 * split extent 2541 */ 2542 orig_ex.ee_len = cpu_to_le16(ee_len - 2543 ext4_ext_get_actual_len(ex3)); 2544 depth = newdepth; 2545 ext4_ext_drop_refs(path); 2546 path = ext4_ext_find_extent(inode, iblock, path); 2547 if (IS_ERR(path)) { 2548 err = PTR_ERR(path); 2549 goto out; 2550 } 2551 eh = path[depth].p_hdr; 2552 ex = path[depth].p_ext; 2553 if (ex2 != &newex) 2554 ex2 = ex; 2555 2556 err = ext4_ext_get_access(handle, inode, path + depth); 2557 if (err) 2558 goto out; 2559 2560 allocated = max_blocks; 2561 2562 /* If extent has less than EXT4_EXT_ZERO_LEN and we are trying 2563 * to insert a extent in the middle zerout directly 2564 * otherwise give the extent a chance to merge to left 2565 */ 2566 if (le16_to_cpu(orig_ex.ee_len) <= EXT4_EXT_ZERO_LEN && 2567 iblock != ee_block) { 2568 err = ext4_ext_zeroout(inode, &orig_ex); 2569 if (err) 2570 goto fix_extent_len; 2571 /* update the extent length and mark as initialized */ 2572 ex->ee_block = orig_ex.ee_block; 2573 ex->ee_len = orig_ex.ee_len; 2574 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2575 ext4_ext_dirty(handle, inode, path + depth); 2576 /* zero out the first half */ 2577 /* blocks available from iblock */ 2578 return allocated; 2579 } 2580 } 2581 /* 2582 * If there was a change of depth as part of the 2583 * insertion of ex3 above, we need to update the length 2584 * of the ex1 extent again here 2585 */ 2586 if (ex1 && ex1 != ex) { 2587 ex1 = ex; 2588 ex1->ee_len = cpu_to_le16(iblock - ee_block); 2589 ext4_ext_mark_uninitialized(ex1); 2590 ex2 = &newex; 2591 } 2592 /* ex2: iblock to iblock + maxblocks-1 : initialised */ 2593 ex2->ee_block = cpu_to_le32(iblock); 2594 ext4_ext_store_pblock(ex2, newblock); 2595 ex2->ee_len = cpu_to_le16(allocated); 2596 if (ex2 != ex) 2597 goto insert; 2598 /* 2599 * New (initialized) extent starts from the first block 2600 * in the current extent. i.e., ex2 == ex 2601 * We have to see if it can be merged with the extent 2602 * on the left. 2603 */ 2604 if (ex2 > EXT_FIRST_EXTENT(eh)) { 2605 /* 2606 * To merge left, pass "ex2 - 1" to try_to_merge(), 2607 * since it merges towards right _only_. 2608 */ 2609 ret = ext4_ext_try_to_merge(inode, path, ex2 - 1); 2610 if (ret) { 2611 err = ext4_ext_correct_indexes(handle, inode, path); 2612 if (err) 2613 goto out; 2614 depth = ext_depth(inode); 2615 ex2--; 2616 } 2617 } 2618 /* 2619 * Try to Merge towards right. This might be required 2620 * only when the whole extent is being written to. 2621 * i.e. ex2 == ex and ex3 == NULL. 2622 */ 2623 if (!ex3) { 2624 ret = ext4_ext_try_to_merge(inode, path, ex2); 2625 if (ret) { 2626 err = ext4_ext_correct_indexes(handle, inode, path); 2627 if (err) 2628 goto out; 2629 } 2630 } 2631 /* Mark modified extent as dirty */ 2632 err = ext4_ext_dirty(handle, inode, path + depth); 2633 goto out; 2634 insert: 2635 err = ext4_ext_insert_extent(handle, inode, path, &newex); 2636 if (err == -ENOSPC) { 2637 err = ext4_ext_zeroout(inode, &orig_ex); 2638 if (err) 2639 goto fix_extent_len; 2640 /* update the extent length and mark as initialized */ 2641 ex->ee_block = orig_ex.ee_block; 2642 ex->ee_len = orig_ex.ee_len; 2643 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2644 ext4_ext_dirty(handle, inode, path + depth); 2645 /* zero out the first half */ 2646 return allocated; 2647 } else if (err) 2648 goto fix_extent_len; 2649 out: 2650 return err ? err : allocated; 2651 2652 fix_extent_len: 2653 ex->ee_block = orig_ex.ee_block; 2654 ex->ee_len = orig_ex.ee_len; 2655 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); 2656 ext4_ext_mark_uninitialized(ex); 2657 ext4_ext_dirty(handle, inode, path + depth); 2658 return err; 2659 } 2660 2661 /* 2662 * Block allocation/map/preallocation routine for extents based files 2663 * 2664 * 2665 * Need to be called with 2666 * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block 2667 * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem) 2668 * 2669 * return > 0, number of of blocks already mapped/allocated 2670 * if create == 0 and these are pre-allocated blocks 2671 * buffer head is unmapped 2672 * otherwise blocks are mapped 2673 * 2674 * return = 0, if plain look up failed (blocks have not been allocated) 2675 * buffer head is unmapped 2676 * 2677 * return < 0, error case. 2678 */ 2679 int ext4_ext_get_blocks(handle_t *handle, struct inode *inode, 2680 ext4_lblk_t iblock, 2681 unsigned long max_blocks, struct buffer_head *bh_result, 2682 int create, int extend_disksize) 2683 { 2684 struct ext4_ext_path *path = NULL; 2685 struct ext4_extent_header *eh; 2686 struct ext4_extent newex, *ex; 2687 ext4_fsblk_t goal, newblock; 2688 int err = 0, depth, ret; 2689 unsigned long allocated = 0; 2690 struct ext4_allocation_request ar; 2691 loff_t disksize; 2692 2693 __clear_bit(BH_New, &bh_result->b_state); 2694 ext_debug("blocks %u/%lu requested for inode %u\n", 2695 iblock, max_blocks, inode->i_ino); 2696 2697 /* check in cache */ 2698 goal = ext4_ext_in_cache(inode, iblock, &newex); 2699 if (goal) { 2700 if (goal == EXT4_EXT_CACHE_GAP) { 2701 if (!create) { 2702 /* 2703 * block isn't allocated yet and 2704 * user doesn't want to allocate it 2705 */ 2706 goto out2; 2707 } 2708 /* we should allocate requested block */ 2709 } else if (goal == EXT4_EXT_CACHE_EXTENT) { 2710 /* block is already allocated */ 2711 newblock = iblock 2712 - le32_to_cpu(newex.ee_block) 2713 + ext_pblock(&newex); 2714 /* number of remaining blocks in the extent */ 2715 allocated = ext4_ext_get_actual_len(&newex) - 2716 (iblock - le32_to_cpu(newex.ee_block)); 2717 goto out; 2718 } else { 2719 BUG(); 2720 } 2721 } 2722 2723 /* find extent for this block */ 2724 path = ext4_ext_find_extent(inode, iblock, NULL); 2725 if (IS_ERR(path)) { 2726 err = PTR_ERR(path); 2727 path = NULL; 2728 goto out2; 2729 } 2730 2731 depth = ext_depth(inode); 2732 2733 /* 2734 * consistent leaf must not be empty; 2735 * this situation is possible, though, _during_ tree modification; 2736 * this is why assert can't be put in ext4_ext_find_extent() 2737 */ 2738 BUG_ON(path[depth].p_ext == NULL && depth != 0); 2739 eh = path[depth].p_hdr; 2740 2741 ex = path[depth].p_ext; 2742 if (ex) { 2743 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block); 2744 ext4_fsblk_t ee_start = ext_pblock(ex); 2745 unsigned short ee_len; 2746 2747 /* 2748 * Uninitialized extents are treated as holes, except that 2749 * we split out initialized portions during a write. 2750 */ 2751 ee_len = ext4_ext_get_actual_len(ex); 2752 /* if found extent covers block, simply return it */ 2753 if (iblock >= ee_block && iblock < ee_block + ee_len) { 2754 newblock = iblock - ee_block + ee_start; 2755 /* number of remaining blocks in the extent */ 2756 allocated = ee_len - (iblock - ee_block); 2757 ext_debug("%u fit into %lu:%d -> %llu\n", iblock, 2758 ee_block, ee_len, newblock); 2759 2760 /* Do not put uninitialized extent in the cache */ 2761 if (!ext4_ext_is_uninitialized(ex)) { 2762 ext4_ext_put_in_cache(inode, ee_block, 2763 ee_len, ee_start, 2764 EXT4_EXT_CACHE_EXTENT); 2765 goto out; 2766 } 2767 if (create == EXT4_CREATE_UNINITIALIZED_EXT) 2768 goto out; 2769 if (!create) { 2770 /* 2771 * We have blocks reserved already. We 2772 * return allocated blocks so that delalloc 2773 * won't do block reservation for us. But 2774 * the buffer head will be unmapped so that 2775 * a read from the block returns 0s. 2776 */ 2777 if (allocated > max_blocks) 2778 allocated = max_blocks; 2779 set_buffer_unwritten(bh_result); 2780 goto out2; 2781 } 2782 2783 ret = ext4_ext_convert_to_initialized(handle, inode, 2784 path, iblock, 2785 max_blocks); 2786 if (ret <= 0) { 2787 err = ret; 2788 goto out2; 2789 } else 2790 allocated = ret; 2791 goto outnew; 2792 } 2793 } 2794 2795 /* 2796 * requested block isn't allocated yet; 2797 * we couldn't try to create block if create flag is zero 2798 */ 2799 if (!create) { 2800 /* 2801 * put just found gap into cache to speed up 2802 * subsequent requests 2803 */ 2804 ext4_ext_put_gap_in_cache(inode, path, iblock); 2805 goto out2; 2806 } 2807 /* 2808 * Okay, we need to do block allocation. 2809 */ 2810 2811 /* find neighbour allocated blocks */ 2812 ar.lleft = iblock; 2813 err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft); 2814 if (err) 2815 goto out2; 2816 ar.lright = iblock; 2817 err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright); 2818 if (err) 2819 goto out2; 2820 2821 /* 2822 * See if request is beyond maximum number of blocks we can have in 2823 * a single extent. For an initialized extent this limit is 2824 * EXT_INIT_MAX_LEN and for an uninitialized extent this limit is 2825 * EXT_UNINIT_MAX_LEN. 2826 */ 2827 if (max_blocks > EXT_INIT_MAX_LEN && 2828 create != EXT4_CREATE_UNINITIALIZED_EXT) 2829 max_blocks = EXT_INIT_MAX_LEN; 2830 else if (max_blocks > EXT_UNINIT_MAX_LEN && 2831 create == EXT4_CREATE_UNINITIALIZED_EXT) 2832 max_blocks = EXT_UNINIT_MAX_LEN; 2833 2834 /* Check if we can really insert (iblock)::(iblock+max_blocks) extent */ 2835 newex.ee_block = cpu_to_le32(iblock); 2836 newex.ee_len = cpu_to_le16(max_blocks); 2837 err = ext4_ext_check_overlap(inode, &newex, path); 2838 if (err) 2839 allocated = ext4_ext_get_actual_len(&newex); 2840 else 2841 allocated = max_blocks; 2842 2843 /* allocate new block */ 2844 ar.inode = inode; 2845 ar.goal = ext4_ext_find_goal(inode, path, iblock); 2846 ar.logical = iblock; 2847 ar.len = allocated; 2848 if (S_ISREG(inode->i_mode)) 2849 ar.flags = EXT4_MB_HINT_DATA; 2850 else 2851 /* disable in-core preallocation for non-regular files */ 2852 ar.flags = 0; 2853 newblock = ext4_mb_new_blocks(handle, &ar, &err); 2854 if (!newblock) 2855 goto out2; 2856 ext_debug("allocate new block: goal %llu, found %llu/%lu\n", 2857 goal, newblock, allocated); 2858 2859 /* try to insert new extent into found leaf and return */ 2860 ext4_ext_store_pblock(&newex, newblock); 2861 newex.ee_len = cpu_to_le16(ar.len); 2862 if (create == EXT4_CREATE_UNINITIALIZED_EXT) /* Mark uninitialized */ 2863 ext4_ext_mark_uninitialized(&newex); 2864 err = ext4_ext_insert_extent(handle, inode, path, &newex); 2865 if (err) { 2866 /* free data blocks we just allocated */ 2867 /* not a good idea to call discard here directly, 2868 * but otherwise we'd need to call it every free() */ 2869 ext4_discard_preallocations(inode); 2870 ext4_free_blocks(handle, inode, ext_pblock(&newex), 2871 ext4_ext_get_actual_len(&newex), 0); 2872 goto out2; 2873 } 2874 2875 /* previous routine could use block we allocated */ 2876 newblock = ext_pblock(&newex); 2877 allocated = ext4_ext_get_actual_len(&newex); 2878 outnew: 2879 if (extend_disksize) { 2880 disksize = ((loff_t) iblock + ar.len) << inode->i_blkbits; 2881 if (disksize > i_size_read(inode)) 2882 disksize = i_size_read(inode); 2883 if (disksize > EXT4_I(inode)->i_disksize) 2884 EXT4_I(inode)->i_disksize = disksize; 2885 } 2886 2887 set_buffer_new(bh_result); 2888 2889 /* Cache only when it is _not_ an uninitialized extent */ 2890 if (create != EXT4_CREATE_UNINITIALIZED_EXT) 2891 ext4_ext_put_in_cache(inode, iblock, allocated, newblock, 2892 EXT4_EXT_CACHE_EXTENT); 2893 out: 2894 if (allocated > max_blocks) 2895 allocated = max_blocks; 2896 ext4_ext_show_leaf(inode, path); 2897 set_buffer_mapped(bh_result); 2898 bh_result->b_bdev = inode->i_sb->s_bdev; 2899 bh_result->b_blocknr = newblock; 2900 out2: 2901 if (path) { 2902 ext4_ext_drop_refs(path); 2903 kfree(path); 2904 } 2905 return err ? err : allocated; 2906 } 2907 2908 void ext4_ext_truncate(struct inode *inode) 2909 { 2910 struct address_space *mapping = inode->i_mapping; 2911 struct super_block *sb = inode->i_sb; 2912 ext4_lblk_t last_block; 2913 handle_t *handle; 2914 int err = 0; 2915 2916 /* 2917 * probably first extent we're gonna free will be last in block 2918 */ 2919 err = ext4_writepage_trans_blocks(inode); 2920 handle = ext4_journal_start(inode, err); 2921 if (IS_ERR(handle)) 2922 return; 2923 2924 if (inode->i_size & (sb->s_blocksize - 1)) 2925 ext4_block_truncate_page(handle, mapping, inode->i_size); 2926 2927 if (ext4_orphan_add(handle, inode)) 2928 goto out_stop; 2929 2930 down_write(&EXT4_I(inode)->i_data_sem); 2931 ext4_ext_invalidate_cache(inode); 2932 2933 ext4_discard_preallocations(inode); 2934 2935 /* 2936 * TODO: optimization is possible here. 2937 * Probably we need not scan at all, 2938 * because page truncation is enough. 2939 */ 2940 2941 /* we have to know where to truncate from in crash case */ 2942 EXT4_I(inode)->i_disksize = inode->i_size; 2943 ext4_mark_inode_dirty(handle, inode); 2944 2945 last_block = (inode->i_size + sb->s_blocksize - 1) 2946 >> EXT4_BLOCK_SIZE_BITS(sb); 2947 err = ext4_ext_remove_space(inode, last_block); 2948 2949 /* In a multi-transaction truncate, we only make the final 2950 * transaction synchronous. 2951 */ 2952 if (IS_SYNC(inode)) 2953 handle->h_sync = 1; 2954 2955 out_stop: 2956 up_write(&EXT4_I(inode)->i_data_sem); 2957 /* 2958 * If this was a simple ftruncate() and the file will remain alive, 2959 * then we need to clear up the orphan record which we created above. 2960 * However, if this was a real unlink then we were called by 2961 * ext4_delete_inode(), and we allow that function to clean up the 2962 * orphan info for us. 2963 */ 2964 if (inode->i_nlink) 2965 ext4_orphan_del(handle, inode); 2966 2967 inode->i_mtime = inode->i_ctime = ext4_current_time(inode); 2968 ext4_mark_inode_dirty(handle, inode); 2969 ext4_journal_stop(handle); 2970 } 2971 2972 static void ext4_falloc_update_inode(struct inode *inode, 2973 int mode, loff_t new_size, int update_ctime) 2974 { 2975 struct timespec now; 2976 2977 if (update_ctime) { 2978 now = current_fs_time(inode->i_sb); 2979 if (!timespec_equal(&inode->i_ctime, &now)) 2980 inode->i_ctime = now; 2981 } 2982 /* 2983 * Update only when preallocation was requested beyond 2984 * the file size. 2985 */ 2986 if (!(mode & FALLOC_FL_KEEP_SIZE)) { 2987 if (new_size > i_size_read(inode)) 2988 i_size_write(inode, new_size); 2989 if (new_size > EXT4_I(inode)->i_disksize) 2990 ext4_update_i_disksize(inode, new_size); 2991 } 2992 2993 } 2994 2995 /* 2996 * preallocate space for a file. This implements ext4's fallocate inode 2997 * operation, which gets called from sys_fallocate system call. 2998 * For block-mapped files, posix_fallocate should fall back to the method 2999 * of writing zeroes to the required new blocks (the same behavior which is 3000 * expected for file systems which do not support fallocate() system call). 3001 */ 3002 long ext4_fallocate(struct inode *inode, int mode, loff_t offset, loff_t len) 3003 { 3004 handle_t *handle; 3005 ext4_lblk_t block; 3006 loff_t new_size; 3007 unsigned long max_blocks; 3008 int ret = 0; 3009 int ret2 = 0; 3010 int retries = 0; 3011 struct buffer_head map_bh; 3012 unsigned int credits, blkbits = inode->i_blkbits; 3013 3014 /* 3015 * currently supporting (pre)allocate mode for extent-based 3016 * files _only_ 3017 */ 3018 if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) 3019 return -EOPNOTSUPP; 3020 3021 /* preallocation to directories is currently not supported */ 3022 if (S_ISDIR(inode->i_mode)) 3023 return -ENODEV; 3024 3025 block = offset >> blkbits; 3026 /* 3027 * We can't just convert len to max_blocks because 3028 * If blocksize = 4096 offset = 3072 and len = 2048 3029 */ 3030 max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits) 3031 - block; 3032 /* 3033 * credits to insert 1 extent into extent tree 3034 */ 3035 credits = ext4_chunk_trans_blocks(inode, max_blocks); 3036 mutex_lock(&inode->i_mutex); 3037 retry: 3038 while (ret >= 0 && ret < max_blocks) { 3039 block = block + ret; 3040 max_blocks = max_blocks - ret; 3041 handle = ext4_journal_start(inode, credits); 3042 if (IS_ERR(handle)) { 3043 ret = PTR_ERR(handle); 3044 break; 3045 } 3046 ret = ext4_get_blocks_wrap(handle, inode, block, 3047 max_blocks, &map_bh, 3048 EXT4_CREATE_UNINITIALIZED_EXT, 0, 0); 3049 if (ret <= 0) { 3050 #ifdef EXT4FS_DEBUG 3051 WARN_ON(ret <= 0); 3052 printk(KERN_ERR "%s: ext4_ext_get_blocks " 3053 "returned error inode#%lu, block=%u, " 3054 "max_blocks=%lu", __func__, 3055 inode->i_ino, block, max_blocks); 3056 #endif 3057 ext4_mark_inode_dirty(handle, inode); 3058 ret2 = ext4_journal_stop(handle); 3059 break; 3060 } 3061 if ((block + ret) >= (EXT4_BLOCK_ALIGN(offset + len, 3062 blkbits) >> blkbits)) 3063 new_size = offset + len; 3064 else 3065 new_size = (block + ret) << blkbits; 3066 3067 ext4_falloc_update_inode(inode, mode, new_size, 3068 buffer_new(&map_bh)); 3069 ext4_mark_inode_dirty(handle, inode); 3070 ret2 = ext4_journal_stop(handle); 3071 if (ret2) 3072 break; 3073 } 3074 if (ret == -ENOSPC && 3075 ext4_should_retry_alloc(inode->i_sb, &retries)) { 3076 ret = 0; 3077 goto retry; 3078 } 3079 mutex_unlock(&inode->i_mutex); 3080 return ret > 0 ? ret2 : ret; 3081 } 3082 3083 /* 3084 * Callback function called for each extent to gather FIEMAP information. 3085 */ 3086 int ext4_ext_fiemap_cb(struct inode *inode, struct ext4_ext_path *path, 3087 struct ext4_ext_cache *newex, struct ext4_extent *ex, 3088 void *data) 3089 { 3090 struct fiemap_extent_info *fieinfo = data; 3091 unsigned long blksize_bits = inode->i_sb->s_blocksize_bits; 3092 __u64 logical; 3093 __u64 physical; 3094 __u64 length; 3095 __u32 flags = 0; 3096 int error; 3097 3098 logical = (__u64)newex->ec_block << blksize_bits; 3099 3100 if (newex->ec_type == EXT4_EXT_CACHE_GAP) { 3101 pgoff_t offset; 3102 struct page *page; 3103 struct buffer_head *bh = NULL; 3104 3105 offset = logical >> PAGE_SHIFT; 3106 page = find_get_page(inode->i_mapping, offset); 3107 if (!page || !page_has_buffers(page)) 3108 return EXT_CONTINUE; 3109 3110 bh = page_buffers(page); 3111 3112 if (!bh) 3113 return EXT_CONTINUE; 3114 3115 if (buffer_delay(bh)) { 3116 flags |= FIEMAP_EXTENT_DELALLOC; 3117 page_cache_release(page); 3118 } else { 3119 page_cache_release(page); 3120 return EXT_CONTINUE; 3121 } 3122 } 3123 3124 physical = (__u64)newex->ec_start << blksize_bits; 3125 length = (__u64)newex->ec_len << blksize_bits; 3126 3127 if (ex && ext4_ext_is_uninitialized(ex)) 3128 flags |= FIEMAP_EXTENT_UNWRITTEN; 3129 3130 /* 3131 * If this extent reaches EXT_MAX_BLOCK, it must be last. 3132 * 3133 * Or if ext4_ext_next_allocated_block is EXT_MAX_BLOCK, 3134 * this also indicates no more allocated blocks. 3135 * 3136 * XXX this might miss a single-block extent at EXT_MAX_BLOCK 3137 */ 3138 if (logical + length - 1 == EXT_MAX_BLOCK || 3139 ext4_ext_next_allocated_block(path) == EXT_MAX_BLOCK) 3140 flags |= FIEMAP_EXTENT_LAST; 3141 3142 error = fiemap_fill_next_extent(fieinfo, logical, physical, 3143 length, flags); 3144 if (error < 0) 3145 return error; 3146 if (error == 1) 3147 return EXT_BREAK; 3148 3149 return EXT_CONTINUE; 3150 } 3151 3152 /* fiemap flags we can handle specified here */ 3153 #define EXT4_FIEMAP_FLAGS (FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR) 3154 3155 int ext4_xattr_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo) 3156 { 3157 __u64 physical = 0; 3158 __u64 length; 3159 __u32 flags = FIEMAP_EXTENT_LAST; 3160 int blockbits = inode->i_sb->s_blocksize_bits; 3161 int error = 0; 3162 3163 /* in-inode? */ 3164 if (EXT4_I(inode)->i_state & EXT4_STATE_XATTR) { 3165 struct ext4_iloc iloc; 3166 int offset; /* offset of xattr in inode */ 3167 3168 error = ext4_get_inode_loc(inode, &iloc); 3169 if (error) 3170 return error; 3171 physical = iloc.bh->b_blocknr << blockbits; 3172 offset = EXT4_GOOD_OLD_INODE_SIZE + 3173 EXT4_I(inode)->i_extra_isize; 3174 physical += offset; 3175 length = EXT4_SB(inode->i_sb)->s_inode_size - offset; 3176 flags |= FIEMAP_EXTENT_DATA_INLINE; 3177 } else { /* external block */ 3178 physical = EXT4_I(inode)->i_file_acl << blockbits; 3179 length = inode->i_sb->s_blocksize; 3180 } 3181 3182 if (physical) 3183 error = fiemap_fill_next_extent(fieinfo, 0, physical, 3184 length, flags); 3185 return (error < 0 ? error : 0); 3186 } 3187 3188 int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, 3189 __u64 start, __u64 len) 3190 { 3191 ext4_lblk_t start_blk; 3192 ext4_lblk_t len_blks; 3193 int error = 0; 3194 3195 /* fallback to generic here if not in extents fmt */ 3196 if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) 3197 return generic_block_fiemap(inode, fieinfo, start, len, 3198 ext4_get_block); 3199 3200 if (fiemap_check_flags(fieinfo, EXT4_FIEMAP_FLAGS)) 3201 return -EBADR; 3202 3203 if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) { 3204 error = ext4_xattr_fiemap(inode, fieinfo); 3205 } else { 3206 start_blk = start >> inode->i_sb->s_blocksize_bits; 3207 len_blks = len >> inode->i_sb->s_blocksize_bits; 3208 3209 /* 3210 * Walk the extent tree gathering extent information. 3211 * ext4_ext_fiemap_cb will push extents back to user. 3212 */ 3213 down_write(&EXT4_I(inode)->i_data_sem); 3214 error = ext4_ext_walk_space(inode, start_blk, len_blks, 3215 ext4_ext_fiemap_cb, fieinfo); 3216 up_write(&EXT4_I(inode)->i_data_sem); 3217 } 3218 3219 return error; 3220 } 3221 3222