1 /* 2 * This file is part of UBIFS. 3 * 4 * Copyright (C) 2006-2008 Nokia Corporation. 5 * 6 * This program is free software; you can redistribute it and/or modify it 7 * under the terms of the GNU General Public License version 2 as published by 8 * the Free Software Foundation. 9 * 10 * This program is distributed in the hope that it will be useful, but WITHOUT 11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 13 * more details. 14 * 15 * You should have received a copy of the GNU General Public License along with 16 * this program; if not, write to the Free Software Foundation, Inc., 51 17 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 18 * 19 * Authors: Adrian Hunter 20 * Artem Bityutskiy (Битюцкий Артём) 21 */ 22 23 /* This file implements TNC functions for committing */ 24 25 #include "ubifs.h" 26 27 /** 28 * make_idx_node - make an index node for fill-the-gaps method of TNC commit. 29 * @c: UBIFS file-system description object 30 * @idx: buffer in which to place new index node 31 * @znode: znode from which to make new index node 32 * @lnum: LEB number where new index node will be written 33 * @offs: offset where new index node will be written 34 * @len: length of new index node 35 */ 36 static int make_idx_node(struct ubifs_info *c, struct ubifs_idx_node *idx, 37 struct ubifs_znode *znode, int lnum, int offs, int len) 38 { 39 struct ubifs_znode *zp; 40 int i, err; 41 42 /* Make index node */ 43 idx->ch.node_type = UBIFS_IDX_NODE; 44 idx->child_cnt = cpu_to_le16(znode->child_cnt); 45 idx->level = cpu_to_le16(znode->level); 46 for (i = 0; i < znode->child_cnt; i++) { 47 struct ubifs_branch *br = ubifs_idx_branch(c, idx, i); 48 struct ubifs_zbranch *zbr = &znode->zbranch[i]; 49 50 key_write_idx(c, &zbr->key, &br->key); 51 br->lnum = cpu_to_le32(zbr->lnum); 52 br->offs = cpu_to_le32(zbr->offs); 53 br->len = cpu_to_le32(zbr->len); 54 if (!zbr->lnum || !zbr->len) { 55 ubifs_err("bad ref in znode"); 56 dbg_dump_znode(c, znode); 57 if (zbr->znode) 58 dbg_dump_znode(c, zbr->znode); 59 } 60 } 61 ubifs_prepare_node(c, idx, len, 0); 62 63 #ifdef CONFIG_UBIFS_FS_DEBUG 64 znode->lnum = lnum; 65 znode->offs = offs; 66 znode->len = len; 67 #endif 68 69 err = insert_old_idx_znode(c, znode); 70 71 /* Update the parent */ 72 zp = znode->parent; 73 if (zp) { 74 struct ubifs_zbranch *zbr; 75 76 zbr = &zp->zbranch[znode->iip]; 77 zbr->lnum = lnum; 78 zbr->offs = offs; 79 zbr->len = len; 80 } else { 81 c->zroot.lnum = lnum; 82 c->zroot.offs = offs; 83 c->zroot.len = len; 84 } 85 c->calc_idx_sz += ALIGN(len, 8); 86 87 atomic_long_dec(&c->dirty_zn_cnt); 88 89 ubifs_assert(ubifs_zn_dirty(znode)); 90 ubifs_assert(test_bit(COW_ZNODE, &znode->flags)); 91 92 __clear_bit(DIRTY_ZNODE, &znode->flags); 93 __clear_bit(COW_ZNODE, &znode->flags); 94 95 return err; 96 } 97 98 /** 99 * fill_gap - make index nodes in gaps in dirty index LEBs. 100 * @c: UBIFS file-system description object 101 * @lnum: LEB number that gap appears in 102 * @gap_start: offset of start of gap 103 * @gap_end: offset of end of gap 104 * @dirt: adds dirty space to this 105 * 106 * This function returns the number of index nodes written into the gap. 107 */ 108 static int fill_gap(struct ubifs_info *c, int lnum, int gap_start, int gap_end, 109 int *dirt) 110 { 111 int len, gap_remains, gap_pos, written, pad_len; 112 113 ubifs_assert((gap_start & 7) == 0); 114 ubifs_assert((gap_end & 7) == 0); 115 ubifs_assert(gap_end >= gap_start); 116 117 gap_remains = gap_end - gap_start; 118 if (!gap_remains) 119 return 0; 120 gap_pos = gap_start; 121 written = 0; 122 while (c->enext) { 123 len = ubifs_idx_node_sz(c, c->enext->child_cnt); 124 if (len < gap_remains) { 125 struct ubifs_znode *znode = c->enext; 126 const int alen = ALIGN(len, 8); 127 int err; 128 129 ubifs_assert(alen <= gap_remains); 130 err = make_idx_node(c, c->ileb_buf + gap_pos, znode, 131 lnum, gap_pos, len); 132 if (err) 133 return err; 134 gap_remains -= alen; 135 gap_pos += alen; 136 c->enext = znode->cnext; 137 if (c->enext == c->cnext) 138 c->enext = NULL; 139 written += 1; 140 } else 141 break; 142 } 143 if (gap_end == c->leb_size) { 144 c->ileb_len = ALIGN(gap_pos, c->min_io_size); 145 /* Pad to end of min_io_size */ 146 pad_len = c->ileb_len - gap_pos; 147 } else 148 /* Pad to end of gap */ 149 pad_len = gap_remains; 150 dbg_gc("LEB %d:%d to %d len %d nodes written %d wasted bytes %d", 151 lnum, gap_start, gap_end, gap_end - gap_start, written, pad_len); 152 ubifs_pad(c, c->ileb_buf + gap_pos, pad_len); 153 *dirt += pad_len; 154 return written; 155 } 156 157 /** 158 * find_old_idx - find an index node obsoleted since the last commit start. 159 * @c: UBIFS file-system description object 160 * @lnum: LEB number of obsoleted index node 161 * @offs: offset of obsoleted index node 162 * 163 * Returns %1 if found and %0 otherwise. 164 */ 165 static int find_old_idx(struct ubifs_info *c, int lnum, int offs) 166 { 167 struct ubifs_old_idx *o; 168 struct rb_node *p; 169 170 p = c->old_idx.rb_node; 171 while (p) { 172 o = rb_entry(p, struct ubifs_old_idx, rb); 173 if (lnum < o->lnum) 174 p = p->rb_left; 175 else if (lnum > o->lnum) 176 p = p->rb_right; 177 else if (offs < o->offs) 178 p = p->rb_left; 179 else if (offs > o->offs) 180 p = p->rb_right; 181 else 182 return 1; 183 } 184 return 0; 185 } 186 187 /** 188 * is_idx_node_in_use - determine if an index node can be overwritten. 189 * @c: UBIFS file-system description object 190 * @key: key of index node 191 * @level: index node level 192 * @lnum: LEB number of index node 193 * @offs: offset of index node 194 * 195 * If @key / @lnum / @offs identify an index node that was not part of the old 196 * index, then this function returns %0 (obsolete). Else if the index node was 197 * part of the old index but is now dirty %1 is returned, else if it is clean %2 198 * is returned. A negative error code is returned on failure. 199 */ 200 static int is_idx_node_in_use(struct ubifs_info *c, union ubifs_key *key, 201 int level, int lnum, int offs) 202 { 203 int ret; 204 205 ret = is_idx_node_in_tnc(c, key, level, lnum, offs); 206 if (ret < 0) 207 return ret; /* Error code */ 208 if (ret == 0) 209 if (find_old_idx(c, lnum, offs)) 210 return 1; 211 return ret; 212 } 213 214 /** 215 * layout_leb_in_gaps - layout index nodes using in-the-gaps method. 216 * @c: UBIFS file-system description object 217 * @p: return LEB number here 218 * 219 * This function lays out new index nodes for dirty znodes using in-the-gaps 220 * method of TNC commit. 221 * This function merely puts the next znode into the next gap, making no attempt 222 * to try to maximise the number of znodes that fit. 223 * This function returns the number of index nodes written into the gaps, or a 224 * negative error code on failure. 225 */ 226 static int layout_leb_in_gaps(struct ubifs_info *c, int *p) 227 { 228 struct ubifs_scan_leb *sleb; 229 struct ubifs_scan_node *snod; 230 int lnum, dirt = 0, gap_start, gap_end, err, written, tot_written; 231 232 tot_written = 0; 233 /* Get an index LEB with lots of obsolete index nodes */ 234 lnum = ubifs_find_dirty_idx_leb(c); 235 if (lnum < 0) 236 /* 237 * There also may be dirt in the index head that could be 238 * filled, however we do not check there at present. 239 */ 240 return lnum; /* Error code */ 241 *p = lnum; 242 dbg_gc("LEB %d", lnum); 243 /* 244 * Scan the index LEB. We use the generic scan for this even though 245 * it is more comprehensive and less efficient than is needed for this 246 * purpose. 247 */ 248 sleb = ubifs_scan(c, lnum, 0, c->ileb_buf, 0); 249 c->ileb_len = 0; 250 if (IS_ERR(sleb)) 251 return PTR_ERR(sleb); 252 gap_start = 0; 253 list_for_each_entry(snod, &sleb->nodes, list) { 254 struct ubifs_idx_node *idx; 255 int in_use, level; 256 257 ubifs_assert(snod->type == UBIFS_IDX_NODE); 258 idx = snod->node; 259 key_read(c, ubifs_idx_key(c, idx), &snod->key); 260 level = le16_to_cpu(idx->level); 261 /* Determine if the index node is in use (not obsolete) */ 262 in_use = is_idx_node_in_use(c, &snod->key, level, lnum, 263 snod->offs); 264 if (in_use < 0) { 265 ubifs_scan_destroy(sleb); 266 return in_use; /* Error code */ 267 } 268 if (in_use) { 269 if (in_use == 1) 270 dirt += ALIGN(snod->len, 8); 271 /* 272 * The obsolete index nodes form gaps that can be 273 * overwritten. This gap has ended because we have 274 * found an index node that is still in use 275 * i.e. not obsolete 276 */ 277 gap_end = snod->offs; 278 /* Try to fill gap */ 279 written = fill_gap(c, lnum, gap_start, gap_end, &dirt); 280 if (written < 0) { 281 ubifs_scan_destroy(sleb); 282 return written; /* Error code */ 283 } 284 tot_written += written; 285 gap_start = ALIGN(snod->offs + snod->len, 8); 286 } 287 } 288 ubifs_scan_destroy(sleb); 289 c->ileb_len = c->leb_size; 290 gap_end = c->leb_size; 291 /* Try to fill gap */ 292 written = fill_gap(c, lnum, gap_start, gap_end, &dirt); 293 if (written < 0) 294 return written; /* Error code */ 295 tot_written += written; 296 if (tot_written == 0) { 297 struct ubifs_lprops lp; 298 299 dbg_gc("LEB %d wrote %d index nodes", lnum, tot_written); 300 err = ubifs_read_one_lp(c, lnum, &lp); 301 if (err) 302 return err; 303 if (lp.free == c->leb_size) { 304 /* 305 * We must have snatched this LEB from the idx_gc list 306 * so we need to correct the free and dirty space. 307 */ 308 err = ubifs_change_one_lp(c, lnum, 309 c->leb_size - c->ileb_len, 310 dirt, 0, 0, 0); 311 if (err) 312 return err; 313 } 314 return 0; 315 } 316 err = ubifs_change_one_lp(c, lnum, c->leb_size - c->ileb_len, dirt, 317 0, 0, 0); 318 if (err) 319 return err; 320 err = ubifs_leb_change(c, lnum, c->ileb_buf, c->ileb_len, 321 UBI_SHORTTERM); 322 if (err) 323 return err; 324 dbg_gc("LEB %d wrote %d index nodes", lnum, tot_written); 325 return tot_written; 326 } 327 328 /** 329 * get_leb_cnt - calculate the number of empty LEBs needed to commit. 330 * @c: UBIFS file-system description object 331 * @cnt: number of znodes to commit 332 * 333 * This function returns the number of empty LEBs needed to commit @cnt znodes 334 * to the current index head. The number is not exact and may be more than 335 * needed. 336 */ 337 static int get_leb_cnt(struct ubifs_info *c, int cnt) 338 { 339 int d; 340 341 /* Assume maximum index node size (i.e. overestimate space needed) */ 342 cnt -= (c->leb_size - c->ihead_offs) / c->max_idx_node_sz; 343 if (cnt < 0) 344 cnt = 0; 345 d = c->leb_size / c->max_idx_node_sz; 346 return DIV_ROUND_UP(cnt, d); 347 } 348 349 /** 350 * layout_in_gaps - in-the-gaps method of committing TNC. 351 * @c: UBIFS file-system description object 352 * @cnt: number of dirty znodes to commit. 353 * 354 * This function lays out new index nodes for dirty znodes using in-the-gaps 355 * method of TNC commit. 356 * 357 * This function returns %0 on success and a negative error code on failure. 358 */ 359 static int layout_in_gaps(struct ubifs_info *c, int cnt) 360 { 361 int err, leb_needed_cnt, written, *p; 362 363 dbg_gc("%d znodes to write", cnt); 364 365 c->gap_lebs = kmalloc(sizeof(int) * (c->lst.idx_lebs + 1), GFP_NOFS); 366 if (!c->gap_lebs) 367 return -ENOMEM; 368 369 p = c->gap_lebs; 370 do { 371 ubifs_assert(p < c->gap_lebs + sizeof(int) * c->lst.idx_lebs); 372 written = layout_leb_in_gaps(c, p); 373 if (written < 0) { 374 err = written; 375 if (err != -ENOSPC) { 376 kfree(c->gap_lebs); 377 c->gap_lebs = NULL; 378 return err; 379 } 380 if (dbg_force_in_the_gaps_enabled()) { 381 /* 382 * Do not print scary warnings if the debugging 383 * option which forces in-the-gaps is enabled. 384 */ 385 ubifs_warn("out of space"); 386 dbg_dump_budg(c, &c->bi); 387 dbg_dump_lprops(c); 388 } 389 /* Try to commit anyway */ 390 err = 0; 391 break; 392 } 393 p++; 394 cnt -= written; 395 leb_needed_cnt = get_leb_cnt(c, cnt); 396 dbg_gc("%d znodes remaining, need %d LEBs, have %d", cnt, 397 leb_needed_cnt, c->ileb_cnt); 398 } while (leb_needed_cnt > c->ileb_cnt); 399 400 *p = -1; 401 return 0; 402 } 403 404 /** 405 * layout_in_empty_space - layout index nodes in empty space. 406 * @c: UBIFS file-system description object 407 * 408 * This function lays out new index nodes for dirty znodes using empty LEBs. 409 * 410 * This function returns %0 on success and a negative error code on failure. 411 */ 412 static int layout_in_empty_space(struct ubifs_info *c) 413 { 414 struct ubifs_znode *znode, *cnext, *zp; 415 int lnum, offs, len, next_len, buf_len, buf_offs, used, avail; 416 int wlen, blen, err; 417 418 cnext = c->enext; 419 if (!cnext) 420 return 0; 421 422 lnum = c->ihead_lnum; 423 buf_offs = c->ihead_offs; 424 425 buf_len = ubifs_idx_node_sz(c, c->fanout); 426 buf_len = ALIGN(buf_len, c->min_io_size); 427 used = 0; 428 avail = buf_len; 429 430 /* Ensure there is enough room for first write */ 431 next_len = ubifs_idx_node_sz(c, cnext->child_cnt); 432 if (buf_offs + next_len > c->leb_size) 433 lnum = -1; 434 435 while (1) { 436 znode = cnext; 437 438 len = ubifs_idx_node_sz(c, znode->child_cnt); 439 440 /* Determine the index node position */ 441 if (lnum == -1) { 442 if (c->ileb_nxt >= c->ileb_cnt) { 443 ubifs_err("out of space"); 444 return -ENOSPC; 445 } 446 lnum = c->ilebs[c->ileb_nxt++]; 447 buf_offs = 0; 448 used = 0; 449 avail = buf_len; 450 } 451 452 offs = buf_offs + used; 453 454 #ifdef CONFIG_UBIFS_FS_DEBUG 455 znode->lnum = lnum; 456 znode->offs = offs; 457 znode->len = len; 458 #endif 459 460 /* Update the parent */ 461 zp = znode->parent; 462 if (zp) { 463 struct ubifs_zbranch *zbr; 464 int i; 465 466 i = znode->iip; 467 zbr = &zp->zbranch[i]; 468 zbr->lnum = lnum; 469 zbr->offs = offs; 470 zbr->len = len; 471 } else { 472 c->zroot.lnum = lnum; 473 c->zroot.offs = offs; 474 c->zroot.len = len; 475 } 476 c->calc_idx_sz += ALIGN(len, 8); 477 478 /* 479 * Once lprops is updated, we can decrease the dirty znode count 480 * but it is easier to just do it here. 481 */ 482 atomic_long_dec(&c->dirty_zn_cnt); 483 484 /* 485 * Calculate the next index node length to see if there is 486 * enough room for it 487 */ 488 cnext = znode->cnext; 489 if (cnext == c->cnext) 490 next_len = 0; 491 else 492 next_len = ubifs_idx_node_sz(c, cnext->child_cnt); 493 494 if (c->min_io_size == 1) { 495 buf_offs += ALIGN(len, 8); 496 if (next_len) { 497 if (buf_offs + next_len <= c->leb_size) 498 continue; 499 err = ubifs_update_one_lp(c, lnum, 0, 500 c->leb_size - buf_offs, 0, 0); 501 if (err) 502 return err; 503 lnum = -1; 504 continue; 505 } 506 err = ubifs_update_one_lp(c, lnum, 507 c->leb_size - buf_offs, 0, 0, 0); 508 if (err) 509 return err; 510 break; 511 } 512 513 /* Update buffer positions */ 514 wlen = used + len; 515 used += ALIGN(len, 8); 516 avail -= ALIGN(len, 8); 517 518 if (next_len != 0 && 519 buf_offs + used + next_len <= c->leb_size && 520 avail > 0) 521 continue; 522 523 if (avail <= 0 && next_len && 524 buf_offs + used + next_len <= c->leb_size) 525 blen = buf_len; 526 else 527 blen = ALIGN(wlen, c->min_io_size); 528 529 /* The buffer is full or there are no more znodes to do */ 530 buf_offs += blen; 531 if (next_len) { 532 if (buf_offs + next_len > c->leb_size) { 533 err = ubifs_update_one_lp(c, lnum, 534 c->leb_size - buf_offs, blen - used, 535 0, 0); 536 if (err) 537 return err; 538 lnum = -1; 539 } 540 used -= blen; 541 if (used < 0) 542 used = 0; 543 avail = buf_len - used; 544 continue; 545 } 546 err = ubifs_update_one_lp(c, lnum, c->leb_size - buf_offs, 547 blen - used, 0, 0); 548 if (err) 549 return err; 550 break; 551 } 552 553 #ifdef CONFIG_UBIFS_FS_DEBUG 554 c->dbg->new_ihead_lnum = lnum; 555 c->dbg->new_ihead_offs = buf_offs; 556 #endif 557 558 return 0; 559 } 560 561 /** 562 * layout_commit - determine positions of index nodes to commit. 563 * @c: UBIFS file-system description object 564 * @no_space: indicates that insufficient empty LEBs were allocated 565 * @cnt: number of znodes to commit 566 * 567 * Calculate and update the positions of index nodes to commit. If there were 568 * an insufficient number of empty LEBs allocated, then index nodes are placed 569 * into the gaps created by obsolete index nodes in non-empty index LEBs. For 570 * this purpose, an obsolete index node is one that was not in the index as at 571 * the end of the last commit. To write "in-the-gaps" requires that those index 572 * LEBs are updated atomically in-place. 573 */ 574 static int layout_commit(struct ubifs_info *c, int no_space, int cnt) 575 { 576 int err; 577 578 if (no_space) { 579 err = layout_in_gaps(c, cnt); 580 if (err) 581 return err; 582 } 583 err = layout_in_empty_space(c); 584 return err; 585 } 586 587 /** 588 * find_first_dirty - find first dirty znode. 589 * @znode: znode to begin searching from 590 */ 591 static struct ubifs_znode *find_first_dirty(struct ubifs_znode *znode) 592 { 593 int i, cont; 594 595 if (!znode) 596 return NULL; 597 598 while (1) { 599 if (znode->level == 0) { 600 if (ubifs_zn_dirty(znode)) 601 return znode; 602 return NULL; 603 } 604 cont = 0; 605 for (i = 0; i < znode->child_cnt; i++) { 606 struct ubifs_zbranch *zbr = &znode->zbranch[i]; 607 608 if (zbr->znode && ubifs_zn_dirty(zbr->znode)) { 609 znode = zbr->znode; 610 cont = 1; 611 break; 612 } 613 } 614 if (!cont) { 615 if (ubifs_zn_dirty(znode)) 616 return znode; 617 return NULL; 618 } 619 } 620 } 621 622 /** 623 * find_next_dirty - find next dirty znode. 624 * @znode: znode to begin searching from 625 */ 626 static struct ubifs_znode *find_next_dirty(struct ubifs_znode *znode) 627 { 628 int n = znode->iip + 1; 629 630 znode = znode->parent; 631 if (!znode) 632 return NULL; 633 for (; n < znode->child_cnt; n++) { 634 struct ubifs_zbranch *zbr = &znode->zbranch[n]; 635 636 if (zbr->znode && ubifs_zn_dirty(zbr->znode)) 637 return find_first_dirty(zbr->znode); 638 } 639 return znode; 640 } 641 642 /** 643 * get_znodes_to_commit - create list of dirty znodes to commit. 644 * @c: UBIFS file-system description object 645 * 646 * This function returns the number of znodes to commit. 647 */ 648 static int get_znodes_to_commit(struct ubifs_info *c) 649 { 650 struct ubifs_znode *znode, *cnext; 651 int cnt = 0; 652 653 c->cnext = find_first_dirty(c->zroot.znode); 654 znode = c->enext = c->cnext; 655 if (!znode) { 656 dbg_cmt("no znodes to commit"); 657 return 0; 658 } 659 cnt += 1; 660 while (1) { 661 ubifs_assert(!test_bit(COW_ZNODE, &znode->flags)); 662 __set_bit(COW_ZNODE, &znode->flags); 663 znode->alt = 0; 664 cnext = find_next_dirty(znode); 665 if (!cnext) { 666 znode->cnext = c->cnext; 667 break; 668 } 669 znode->cnext = cnext; 670 znode = cnext; 671 cnt += 1; 672 } 673 dbg_cmt("committing %d znodes", cnt); 674 ubifs_assert(cnt == atomic_long_read(&c->dirty_zn_cnt)); 675 return cnt; 676 } 677 678 /** 679 * alloc_idx_lebs - allocate empty LEBs to be used to commit. 680 * @c: UBIFS file-system description object 681 * @cnt: number of znodes to commit 682 * 683 * This function returns %-ENOSPC if it cannot allocate a sufficient number of 684 * empty LEBs. %0 is returned on success, otherwise a negative error code 685 * is returned. 686 */ 687 static int alloc_idx_lebs(struct ubifs_info *c, int cnt) 688 { 689 int i, leb_cnt, lnum; 690 691 c->ileb_cnt = 0; 692 c->ileb_nxt = 0; 693 leb_cnt = get_leb_cnt(c, cnt); 694 dbg_cmt("need about %d empty LEBS for TNC commit", leb_cnt); 695 if (!leb_cnt) 696 return 0; 697 c->ilebs = kmalloc(leb_cnt * sizeof(int), GFP_NOFS); 698 if (!c->ilebs) 699 return -ENOMEM; 700 for (i = 0; i < leb_cnt; i++) { 701 lnum = ubifs_find_free_leb_for_idx(c); 702 if (lnum < 0) 703 return lnum; 704 c->ilebs[c->ileb_cnt++] = lnum; 705 dbg_cmt("LEB %d", lnum); 706 } 707 if (dbg_force_in_the_gaps()) 708 return -ENOSPC; 709 return 0; 710 } 711 712 /** 713 * free_unused_idx_lebs - free unused LEBs that were allocated for the commit. 714 * @c: UBIFS file-system description object 715 * 716 * It is possible that we allocate more empty LEBs for the commit than we need. 717 * This functions frees the surplus. 718 * 719 * This function returns %0 on success and a negative error code on failure. 720 */ 721 static int free_unused_idx_lebs(struct ubifs_info *c) 722 { 723 int i, err = 0, lnum, er; 724 725 for (i = c->ileb_nxt; i < c->ileb_cnt; i++) { 726 lnum = c->ilebs[i]; 727 dbg_cmt("LEB %d", lnum); 728 er = ubifs_change_one_lp(c, lnum, LPROPS_NC, LPROPS_NC, 0, 729 LPROPS_INDEX | LPROPS_TAKEN, 0); 730 if (!err) 731 err = er; 732 } 733 return err; 734 } 735 736 /** 737 * free_idx_lebs - free unused LEBs after commit end. 738 * @c: UBIFS file-system description object 739 * 740 * This function returns %0 on success and a negative error code on failure. 741 */ 742 static int free_idx_lebs(struct ubifs_info *c) 743 { 744 int err; 745 746 err = free_unused_idx_lebs(c); 747 kfree(c->ilebs); 748 c->ilebs = NULL; 749 return err; 750 } 751 752 /** 753 * ubifs_tnc_start_commit - start TNC commit. 754 * @c: UBIFS file-system description object 755 * @zroot: new index root position is returned here 756 * 757 * This function prepares the list of indexing nodes to commit and lays out 758 * their positions on flash. If there is not enough free space it uses the 759 * in-gap commit method. Returns zero in case of success and a negative error 760 * code in case of failure. 761 */ 762 int ubifs_tnc_start_commit(struct ubifs_info *c, struct ubifs_zbranch *zroot) 763 { 764 int err = 0, cnt; 765 766 mutex_lock(&c->tnc_mutex); 767 err = dbg_check_tnc(c, 1); 768 if (err) 769 goto out; 770 cnt = get_znodes_to_commit(c); 771 if (cnt != 0) { 772 int no_space = 0; 773 774 err = alloc_idx_lebs(c, cnt); 775 if (err == -ENOSPC) 776 no_space = 1; 777 else if (err) 778 goto out_free; 779 err = layout_commit(c, no_space, cnt); 780 if (err) 781 goto out_free; 782 ubifs_assert(atomic_long_read(&c->dirty_zn_cnt) == 0); 783 err = free_unused_idx_lebs(c); 784 if (err) 785 goto out; 786 } 787 destroy_old_idx(c); 788 memcpy(zroot, &c->zroot, sizeof(struct ubifs_zbranch)); 789 790 err = ubifs_save_dirty_idx_lnums(c); 791 if (err) 792 goto out; 793 794 spin_lock(&c->space_lock); 795 /* 796 * Although we have not finished committing yet, update size of the 797 * committed index ('c->bi.old_idx_sz') and zero out the index growth 798 * budget. It is OK to do this now, because we've reserved all the 799 * space which is needed to commit the index, and it is save for the 800 * budgeting subsystem to assume the index is already committed, 801 * even though it is not. 802 */ 803 ubifs_assert(c->bi.min_idx_lebs == ubifs_calc_min_idx_lebs(c)); 804 c->bi.old_idx_sz = c->calc_idx_sz; 805 c->bi.uncommitted_idx = 0; 806 c->bi.min_idx_lebs = ubifs_calc_min_idx_lebs(c); 807 spin_unlock(&c->space_lock); 808 mutex_unlock(&c->tnc_mutex); 809 810 dbg_cmt("number of index LEBs %d", c->lst.idx_lebs); 811 dbg_cmt("size of index %llu", c->calc_idx_sz); 812 return err; 813 814 out_free: 815 free_idx_lebs(c); 816 out: 817 mutex_unlock(&c->tnc_mutex); 818 return err; 819 } 820 821 /** 822 * write_index - write index nodes. 823 * @c: UBIFS file-system description object 824 * 825 * This function writes the index nodes whose positions were laid out in the 826 * layout_in_empty_space function. 827 */ 828 static int write_index(struct ubifs_info *c) 829 { 830 struct ubifs_idx_node *idx; 831 struct ubifs_znode *znode, *cnext; 832 int i, lnum, offs, len, next_len, buf_len, buf_offs, used; 833 int avail, wlen, err, lnum_pos = 0; 834 835 cnext = c->enext; 836 if (!cnext) 837 return 0; 838 839 /* 840 * Always write index nodes to the index head so that index nodes and 841 * other types of nodes are never mixed in the same erase block. 842 */ 843 lnum = c->ihead_lnum; 844 buf_offs = c->ihead_offs; 845 846 /* Allocate commit buffer */ 847 buf_len = ALIGN(c->max_idx_node_sz, c->min_io_size); 848 used = 0; 849 avail = buf_len; 850 851 /* Ensure there is enough room for first write */ 852 next_len = ubifs_idx_node_sz(c, cnext->child_cnt); 853 if (buf_offs + next_len > c->leb_size) { 854 err = ubifs_update_one_lp(c, lnum, LPROPS_NC, 0, 0, 855 LPROPS_TAKEN); 856 if (err) 857 return err; 858 lnum = -1; 859 } 860 861 while (1) { 862 cond_resched(); 863 864 znode = cnext; 865 idx = c->cbuf + used; 866 867 /* Make index node */ 868 idx->ch.node_type = UBIFS_IDX_NODE; 869 idx->child_cnt = cpu_to_le16(znode->child_cnt); 870 idx->level = cpu_to_le16(znode->level); 871 for (i = 0; i < znode->child_cnt; i++) { 872 struct ubifs_branch *br = ubifs_idx_branch(c, idx, i); 873 struct ubifs_zbranch *zbr = &znode->zbranch[i]; 874 875 key_write_idx(c, &zbr->key, &br->key); 876 br->lnum = cpu_to_le32(zbr->lnum); 877 br->offs = cpu_to_le32(zbr->offs); 878 br->len = cpu_to_le32(zbr->len); 879 if (!zbr->lnum || !zbr->len) { 880 ubifs_err("bad ref in znode"); 881 dbg_dump_znode(c, znode); 882 if (zbr->znode) 883 dbg_dump_znode(c, zbr->znode); 884 } 885 } 886 len = ubifs_idx_node_sz(c, znode->child_cnt); 887 ubifs_prepare_node(c, idx, len, 0); 888 889 /* Determine the index node position */ 890 if (lnum == -1) { 891 lnum = c->ilebs[lnum_pos++]; 892 buf_offs = 0; 893 used = 0; 894 avail = buf_len; 895 } 896 offs = buf_offs + used; 897 898 #ifdef CONFIG_UBIFS_FS_DEBUG 899 if (lnum != znode->lnum || offs != znode->offs || 900 len != znode->len) { 901 ubifs_err("inconsistent znode posn"); 902 return -EINVAL; 903 } 904 #endif 905 906 /* Grab some stuff from znode while we still can */ 907 cnext = znode->cnext; 908 909 ubifs_assert(ubifs_zn_dirty(znode)); 910 ubifs_assert(test_bit(COW_ZNODE, &znode->flags)); 911 912 /* 913 * It is important that other threads should see %DIRTY_ZNODE 914 * flag cleared before %COW_ZNODE. Specifically, it matters in 915 * the 'dirty_cow_znode()' function. This is the reason for the 916 * first barrier. Also, we want the bit changes to be seen to 917 * other threads ASAP, to avoid unnecesarry copying, which is 918 * the reason for the second barrier. 919 */ 920 clear_bit(DIRTY_ZNODE, &znode->flags); 921 smp_mb__before_clear_bit(); 922 clear_bit(COW_ZNODE, &znode->flags); 923 smp_mb__after_clear_bit(); 924 925 /* Do not access znode from this point on */ 926 927 /* Update buffer positions */ 928 wlen = used + len; 929 used += ALIGN(len, 8); 930 avail -= ALIGN(len, 8); 931 932 /* 933 * Calculate the next index node length to see if there is 934 * enough room for it 935 */ 936 if (cnext == c->cnext) 937 next_len = 0; 938 else 939 next_len = ubifs_idx_node_sz(c, cnext->child_cnt); 940 941 if (c->min_io_size == 1) { 942 /* 943 * Write the prepared index node immediately if there is 944 * no minimum IO size 945 */ 946 err = ubifs_leb_write(c, lnum, c->cbuf, buf_offs, 947 wlen, UBI_SHORTTERM); 948 if (err) 949 return err; 950 buf_offs += ALIGN(wlen, 8); 951 if (next_len) { 952 used = 0; 953 avail = buf_len; 954 if (buf_offs + next_len > c->leb_size) { 955 err = ubifs_update_one_lp(c, lnum, 956 LPROPS_NC, 0, 0, LPROPS_TAKEN); 957 if (err) 958 return err; 959 lnum = -1; 960 } 961 continue; 962 } 963 } else { 964 int blen, nxt_offs = buf_offs + used + next_len; 965 966 if (next_len && nxt_offs <= c->leb_size) { 967 if (avail > 0) 968 continue; 969 else 970 blen = buf_len; 971 } else { 972 wlen = ALIGN(wlen, 8); 973 blen = ALIGN(wlen, c->min_io_size); 974 ubifs_pad(c, c->cbuf + wlen, blen - wlen); 975 } 976 /* 977 * The buffer is full or there are no more znodes 978 * to do 979 */ 980 err = ubifs_leb_write(c, lnum, c->cbuf, buf_offs, 981 blen, UBI_SHORTTERM); 982 if (err) 983 return err; 984 buf_offs += blen; 985 if (next_len) { 986 if (nxt_offs > c->leb_size) { 987 err = ubifs_update_one_lp(c, lnum, 988 LPROPS_NC, 0, 0, LPROPS_TAKEN); 989 if (err) 990 return err; 991 lnum = -1; 992 } 993 used -= blen; 994 if (used < 0) 995 used = 0; 996 avail = buf_len - used; 997 memmove(c->cbuf, c->cbuf + blen, used); 998 continue; 999 } 1000 } 1001 break; 1002 } 1003 1004 #ifdef CONFIG_UBIFS_FS_DEBUG 1005 if (lnum != c->dbg->new_ihead_lnum || 1006 buf_offs != c->dbg->new_ihead_offs) { 1007 ubifs_err("inconsistent ihead"); 1008 return -EINVAL; 1009 } 1010 #endif 1011 1012 c->ihead_lnum = lnum; 1013 c->ihead_offs = buf_offs; 1014 1015 return 0; 1016 } 1017 1018 /** 1019 * free_obsolete_znodes - free obsolete znodes. 1020 * @c: UBIFS file-system description object 1021 * 1022 * At the end of commit end, obsolete znodes are freed. 1023 */ 1024 static void free_obsolete_znodes(struct ubifs_info *c) 1025 { 1026 struct ubifs_znode *znode, *cnext; 1027 1028 cnext = c->cnext; 1029 do { 1030 znode = cnext; 1031 cnext = znode->cnext; 1032 if (test_bit(OBSOLETE_ZNODE, &znode->flags)) 1033 kfree(znode); 1034 else { 1035 znode->cnext = NULL; 1036 atomic_long_inc(&c->clean_zn_cnt); 1037 atomic_long_inc(&ubifs_clean_zn_cnt); 1038 } 1039 } while (cnext != c->cnext); 1040 } 1041 1042 /** 1043 * return_gap_lebs - return LEBs used by the in-gap commit method. 1044 * @c: UBIFS file-system description object 1045 * 1046 * This function clears the "taken" flag for the LEBs which were used by the 1047 * "commit in-the-gaps" method. 1048 */ 1049 static int return_gap_lebs(struct ubifs_info *c) 1050 { 1051 int *p, err; 1052 1053 if (!c->gap_lebs) 1054 return 0; 1055 1056 dbg_cmt(""); 1057 for (p = c->gap_lebs; *p != -1; p++) { 1058 err = ubifs_change_one_lp(c, *p, LPROPS_NC, LPROPS_NC, 0, 1059 LPROPS_TAKEN, 0); 1060 if (err) 1061 return err; 1062 } 1063 1064 kfree(c->gap_lebs); 1065 c->gap_lebs = NULL; 1066 return 0; 1067 } 1068 1069 /** 1070 * ubifs_tnc_end_commit - update the TNC for commit end. 1071 * @c: UBIFS file-system description object 1072 * 1073 * Write the dirty znodes. 1074 */ 1075 int ubifs_tnc_end_commit(struct ubifs_info *c) 1076 { 1077 int err; 1078 1079 if (!c->cnext) 1080 return 0; 1081 1082 err = return_gap_lebs(c); 1083 if (err) 1084 return err; 1085 1086 err = write_index(c); 1087 if (err) 1088 return err; 1089 1090 mutex_lock(&c->tnc_mutex); 1091 1092 dbg_cmt("TNC height is %d", c->zroot.znode->level + 1); 1093 1094 free_obsolete_znodes(c); 1095 1096 c->cnext = NULL; 1097 kfree(c->ilebs); 1098 c->ilebs = NULL; 1099 1100 mutex_unlock(&c->tnc_mutex); 1101 1102 return 0; 1103 } 1104