fs/ubifs/log.c

   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: Artem Bityutskiy (Битюцкий Артём)
  20  *          Adrian Hunter
  21  */
  22
  23 /*
  24  * This file is a part of UBIFS journal implementation and contains various
  25  * functions which manipulate the log. The log is a fixed area on the flash
  26  * which does not contain any data but refers to buds. The log is a part of the
  27  * journal.
  28  */
  29
  30 #include "ubifs.h"
  31
  32 static int dbg_check_bud_bytes(struct ubifs_info *c);
  33
  34 /**
  35  * ubifs_search_bud - search bud LEB.
  36  * @c: UBIFS file-system description object
  37  * @lnum: logical eraseblock number to search
  38  *
  39  * This function searches bud LEB @lnum. Returns bud description object in case
  40  * of success and %NULL if there is no bud with this LEB number.
  41  */
  42 struct ubifs_bud *ubifs_search_bud(struct ubifs_info *c, int lnum)
  43 {
  44         struct rb_node *p;
  45         struct ubifs_bud *bud;
  46
  47         spin_lock(&c->buds_lock);
  48         p = c->buds.rb_node;
  49         while (p) {
  50                 bud = rb_entry(p, struct ubifs_bud, rb);
  51                 if (lnum < bud->lnum)
  52                         p = p->rb_left;
  53                 else if (lnum > bud->lnum)
  54                         p = p->rb_right;
  55                 else {
  56                         spin_unlock(&c->buds_lock);
  57                         return bud;
  58                 }
  59         }
  60         spin_unlock(&c->buds_lock);
  61         return NULL;
  62 }
  63
  64 /**
  65  * ubifs_get_wbuf - get the wbuf associated with a LEB, if there is one.
  66  * @c: UBIFS file-system description object
  67  * @lnum: logical eraseblock number to search
  68  *
  69  * This functions returns the wbuf for @lnum or %NULL if there is not one.
  70  */
  71 struct ubifs_wbuf *ubifs_get_wbuf(struct ubifs_info *c, int lnum)
  72 {
  73         struct rb_node *p;
  74         struct ubifs_bud *bud;
  75         int jhead;
  76
  77         if (!c->jheads)
  78                 return NULL;
  79
  80         spin_lock(&c->buds_lock);
  81         p = c->buds.rb_node;
  82         while (p) {
  83                 bud = rb_entry(p, struct ubifs_bud, rb);
  84                 if (lnum < bud->lnum)
  85                         p = p->rb_left;
  86                 else if (lnum > bud->lnum)
  87                         p = p->rb_right;
  88                 else {
  89                         jhead = bud->jhead;
  90                         spin_unlock(&c->buds_lock);
  91                         return &c->jheads[jhead].wbuf;
  92                 }
  93         }
  94         spin_unlock(&c->buds_lock);
  95         return NULL;
  96 }
  97
  98 /**
  99  * empty_log_bytes - calculate amount of empty space in the log.
 100  * @c: UBIFS file-system description object
 101  */
 102 static inline long long empty_log_bytes(const struct ubifs_info *c)
 103 {
 104         long long h, t;
 105
 106         h = (long long)c->lhead_lnum * c->leb_size + c->lhead_offs;
 107         t = (long long)c->ltail_lnum * c->leb_size;
 108
 109         if (h > t)
 110                 return c->log_bytes - h + t;
 111         else if (h != t)
 112                 return t - h;
 113         else if (c->lhead_lnum != c->ltail_lnum)
 114                 return 0;
 115         else
 116                 return c->log_bytes;
 117 }
 118
 119 /**
 120  * ubifs_add_bud - add bud LEB to the tree of buds and its journal head list.
 121  * @c: UBIFS file-system description object
 122  * @bud: the bud to add
 123  */
 124 void ubifs_add_bud(struct ubifs_info *c, struct ubifs_bud *bud)
 125 {
 126         struct rb_node **p, *parent = NULL;
 127         struct ubifs_bud *b;
 128         struct ubifs_jhead *jhead;
 129
 130         spin_lock(&c->buds_lock);
 131         p = &c->buds.rb_node;
 132         while (*p) {
 133                 parent = *p;
 134                 b = rb_entry(parent, struct ubifs_bud, rb);
 135                 ubifs_assert(bud->lnum != b->lnum);
 136                 if (bud->lnum < b->lnum)
 137                         p = &(*p)->rb_left;
 138                 else
 139                         p = &(*p)->rb_right;
 140         }
 141
 142         rb_link_node(&bud->rb, parent, p);
 143         rb_insert_color(&bud->rb, &c->buds);
 144         if (c->jheads) {
 145                 jhead = &c->jheads[bud->jhead];
 146                 list_add_tail(&bud->list, &jhead->buds_list);
 147         } else
 148                 ubifs_assert(c->replaying && c->ro_mount);
 149
 150         /*
 151          * Note, although this is a new bud, we anyway account this space now,
 152          * before any data has been written to it, because this is about to
 153          * guarantee fixed mount time, and this bud will anyway be read and
 154          * scanned.
 155          */
 156         c->bud_bytes += c->leb_size - bud->start;
 157
 158         dbg_log("LEB %d:%d, jhead %s, bud_bytes %lld", bud->lnum,
 159                 bud->start, dbg_jhead(bud->jhead), c->bud_bytes);
 160         spin_unlock(&c->buds_lock);
 161 }
 162
 163 /**
 164  * ubifs_add_bud_to_log - add a new bud to the log.
 165  * @c: UBIFS file-system description object
 166  * @jhead: journal head the bud belongs to
 167  * @lnum: LEB number of the bud
 168  * @offs: starting offset of the bud
 169  *
 170  * This function writes a reference node for the new bud LEB @lnum to the log,
 171  * and adds it to the buds trees. It also makes sure that log size does not
 172  * exceed the 'c->max_bud_bytes' limit. Returns zero in case of success,
 173  * %-EAGAIN if commit is required, and a negative error code in case of
 174  * failure.
 175  */
 176 int ubifs_add_bud_to_log(struct ubifs_info *c, int jhead, int lnum, int offs)
 177 {
 178         int err;
 179         struct ubifs_bud *bud;
 180         struct ubifs_ref_node *ref;
 181
 182         bud = kmalloc(sizeof(struct ubifs_bud), GFP_NOFS);
 183         if (!bud)
 184                 return -ENOMEM;
 185         ref = kzalloc(c->ref_node_alsz, GFP_NOFS);
 186         if (!ref) {
 187                 kfree(bud);
 188                 return -ENOMEM;
 189         }
 190
 191         mutex_lock(&c->log_mutex);
 192         ubifs_assert(!c->ro_media && !c->ro_mount);
 193         if (c->ro_error) {
 194                 err = -EROFS;
 195                 goto out_unlock;
 196         }
 197
 198         /* Make sure we have enough space in the log */
 199         if (empty_log_bytes(c) - c->ref_node_alsz < c->min_log_bytes) {
 200                 dbg_log("not enough log space - %lld, required %d",
 201                         empty_log_bytes(c), c->min_log_bytes);
 202                 ubifs_commit_required(c);
 203                 err = -EAGAIN;
 204                 goto out_unlock;
 205         }
 206
 207         /*
 208          * Make sure the amount of space in buds will not exceed the
 209          * 'c->max_bud_bytes' limit, because we want to guarantee mount time
 210          * limits.
 211          *
 212          * It is not necessary to hold @c->buds_lock when reading @c->bud_bytes
 213          * because we are holding @c->log_mutex. All @c->bud_bytes take place
 214          * when both @c->log_mutex and @c->bud_bytes are locked.
 215          */
 216         if (c->bud_bytes + c->leb_size - offs > c->max_bud_bytes) {
 217                 dbg_log("bud bytes %lld (%lld max), require commit",
 218                         c->bud_bytes, c->max_bud_bytes);
 219                 ubifs_commit_required(c);
 220                 err = -EAGAIN;
 221                 goto out_unlock;
 222         }
 223
 224         /*
 225          * If the journal is full enough - start background commit. Note, it is
 226          * OK to read 'c->cmt_state' without spinlock because integer reads
 227          * are atomic in the kernel.
 228          */
 229         if (c->bud_bytes >= c->bg_bud_bytes &&
 230             c->cmt_state == COMMIT_RESTING) {
 231                 dbg_log("bud bytes %lld (%lld max), initiate BG commit",
 232                         c->bud_bytes, c->max_bud_bytes);
 233                 ubifs_request_bg_commit(c);
 234         }
 235
 236         bud->lnum = lnum;
 237         bud->start = offs;
 238         bud->jhead = jhead;
 239
 240         ref->ch.node_type = UBIFS_REF_NODE;
 241         ref->lnum = cpu_to_le32(bud->lnum);
 242         ref->offs = cpu_to_le32(bud->start);
 243         ref->jhead = cpu_to_le32(jhead);
 244
 245         if (c->lhead_offs > c->leb_size - c->ref_node_alsz) {
 246                 c->lhead_lnum = ubifs_next_log_lnum(c, c->lhead_lnum);
 247                 ubifs_assert(c->lhead_lnum != c->ltail_lnum);
 248                 c->lhead_offs = 0;
 249         }
 250
 251         if (c->lhead_offs == 0) {
 252                 /* Must ensure next log LEB has been unmapped */
 253                 err = ubifs_leb_unmap(c, c->lhead_lnum);
 254                 if (err)
 255                         goto out_unlock;
 256         }
 257
 258         if (bud->start == 0) {
 259                 /*
 260                  * Before writing the LEB reference which refers an empty LEB
 261                  * to the log, we have to make sure it is mapped, because
 262                  * otherwise we'd risk to refer an LEB with garbage in case of
 263                  * an unclean reboot, because the target LEB might have been
 264                  * unmapped, but not yet physically erased.
 265                  */
 266                 err = ubifs_leb_map(c, bud->lnum);
 267                 if (err)
 268                         goto out_unlock;
 269         }
 270
 271         dbg_log("write ref LEB %d:%d",
 272                 c->lhead_lnum, c->lhead_offs);
 273         err = ubifs_write_node(c, ref, UBIFS_REF_NODE_SZ, c->lhead_lnum,
 274                                c->lhead_offs);
 275         if (err)
 276                 goto out_unlock;
 277
 278         c->lhead_offs += c->ref_node_alsz;
 279
 280         ubifs_add_bud(c, bud);
 281
 282         mutex_unlock(&c->log_mutex);
 283         kfree(ref);
 284         return 0;
 285
 286 out_unlock:
 287         mutex_unlock(&c->log_mutex);
 288         kfree(ref);
 289         kfree(bud);
 290         return err;
 291 }
 292
 293 /**
 294  * remove_buds - remove used buds.
 295  * @c: UBIFS file-system description object
 296  *
 297  * This function removes use buds from the buds tree. It does not remove the
 298  * buds which are pointed to by journal heads.
 299  */
 300 static void remove_buds(struct ubifs_info *c)
 301 {
 302         struct rb_node *p;
 303
 304         ubifs_assert(list_empty(&c->old_buds));
 305         c->cmt_bud_bytes = 0;
 306         spin_lock(&c->buds_lock);
 307         p = rb_first(&c->buds);
 308         while (p) {
 309                 struct rb_node *p1 = p;
 310                 struct ubifs_bud *bud;
 311                 struct ubifs_wbuf *wbuf;
 312
 313                 p = rb_next(p);
 314                 bud = rb_entry(p1, struct ubifs_bud, rb);
 315                 wbuf = &c->jheads[bud->jhead].wbuf;
 316
 317                 if (wbuf->lnum == bud->lnum) {
 318                         /*
 319                          * Do not remove buds which are pointed to by journal
 320                          * heads (non-closed buds).
 321                          */
 322                         c->cmt_bud_bytes += wbuf->offs - bud->start;
 323                         dbg_log("preserve %d:%d, jhead %s, bud bytes %d, cmt_bud_bytes %lld",
 324                                 bud->lnum, bud->start, dbg_jhead(bud->jhead),
 325                                 wbuf->offs - bud->start, c->cmt_bud_bytes);
 326                         bud->start = wbuf->offs;
 327                 } else {
 328                         c->cmt_bud_bytes += c->leb_size - bud->start;
 329                         dbg_log("remove %d:%d, jhead %s, bud bytes %d, cmt_bud_bytes %lld",
 330                                 bud->lnum, bud->start, dbg_jhead(bud->jhead),
 331                                 c->leb_size - bud->start, c->cmt_bud_bytes);
 332                         rb_erase(p1, &c->buds);
 333                         /*
 334                          * If the commit does not finish, the recovery will need
 335                          * to replay the journal, in which case the old buds
 336                          * must be unchanged. Do not release them until post
 337                          * commit i.e. do not allow them to be garbage
 338                          * collected.
 339                          */
 340                         list_move(&bud->list, &c->old_buds);
 341                 }
 342         }
 343         spin_unlock(&c->buds_lock);
 344 }
 345
 346 /**
 347  * ubifs_log_start_commit - start commit.
 348  * @c: UBIFS file-system description object
 349  * @ltail_lnum: return new log tail LEB number
 350  *
 351  * The commit operation starts with writing "commit start" node to the log and
 352  * reference nodes for all journal heads which will define new journal after
 353  * the commit has been finished. The commit start and reference nodes are
 354  * written in one go to the nearest empty log LEB (hence, when commit is
 355  * finished UBIFS may safely unmap all the previous log LEBs). This function
 356  * returns zero in case of success and a negative error code in case of
 357  * failure.
 358  */
 359 int ubifs_log_start_commit(struct ubifs_info *c, int *ltail_lnum)
 360 {
 361         void *buf;
 362         struct ubifs_cs_node *cs;
 363         struct ubifs_ref_node *ref;
 364         int err, i, max_len, len;
 365
 366         err = dbg_check_bud_bytes(c);
 367         if (err)
 368                 return err;
 369
 370         max_len = UBIFS_CS_NODE_SZ + c->jhead_cnt * UBIFS_REF_NODE_SZ;
 371         max_len = ALIGN(max_len, c->min_io_size);
 372         buf = cs = kmalloc(max_len, GFP_NOFS);
 373         if (!buf)
 374                 return -ENOMEM;
 375
 376         cs->ch.node_type = UBIFS_CS_NODE;
 377         cs->cmt_no = cpu_to_le64(c->cmt_no);
 378         ubifs_prepare_node(c, cs, UBIFS_CS_NODE_SZ, 0);
 379
 380         /*
 381          * Note, we do not lock 'c->log_mutex' because this is the commit start
 382          * phase and we are exclusively using the log. And we do not lock
 383          * write-buffer because nobody can write to the file-system at this
 384          * phase.
 385          */
 386
 387         len = UBIFS_CS_NODE_SZ;
 388         for (i = 0; i < c->jhead_cnt; i++) {
 389                 int lnum = c->jheads[i].wbuf.lnum;
 390                 int offs = c->jheads[i].wbuf.offs;
 391
 392                 if (lnum == -1 || offs == c->leb_size)
 393                         continue;
 394
 395                 dbg_log("add ref to LEB %d:%d for jhead %s",
 396                         lnum, offs, dbg_jhead(i));
 397                 ref = buf + len;
 398                 ref->ch.node_type = UBIFS_REF_NODE;
 399                 ref->lnum = cpu_to_le32(lnum);
 400                 ref->offs = cpu_to_le32(offs);
 401                 ref->jhead = cpu_to_le32(i);
 402
 403                 ubifs_prepare_node(c, ref, UBIFS_REF_NODE_SZ, 0);
 404                 len += UBIFS_REF_NODE_SZ;
 405         }
 406
 407         ubifs_pad(c, buf + len, ALIGN(len, c->min_io_size) - len);
 408
 409         /* Switch to the next log LEB */
 410         if (c->lhead_offs) {
 411                 c->lhead_lnum = ubifs_next_log_lnum(c, c->lhead_lnum);
 412                 ubifs_assert(c->lhead_lnum != c->ltail_lnum);
 413                 c->lhead_offs = 0;
 414         }
 415
 416         /* Must ensure next LEB has been unmapped */
 417         err = ubifs_leb_unmap(c, c->lhead_lnum);
 418         if (err)
 419                 goto out;
 420
 421         len = ALIGN(len, c->min_io_size);
 422         dbg_log("writing commit start at LEB %d:0, len %d", c->lhead_lnum, len);
 423         err = ubifs_leb_write(c, c->lhead_lnum, cs, 0, len);
 424         if (err)
 425                 goto out;
 426
 427         *ltail_lnum = c->lhead_lnum;
 428
 429         c->lhead_offs += len;
 430         if (c->lhead_offs == c->leb_size) {
 431                 c->lhead_lnum = ubifs_next_log_lnum(c, c->lhead_lnum);
 432                 c->lhead_offs = 0;
 433         }
 434
 435         remove_buds(c);
 436
 437         /*
 438          * We have started the commit and now users may use the rest of the log
 439          * for new writes.
 440          */
 441         c->min_log_bytes = 0;
 442
 443 out:
 444         kfree(buf);
 445         return err;
 446 }
 447
 448 /**
 449  * ubifs_log_end_commit - end commit.
 450  * @c: UBIFS file-system description object
 451  * @ltail_lnum: new log tail LEB number
 452  *
 453  * This function is called on when the commit operation was finished. It
 454  * moves log tail to new position and updates the master node so that it stores
 455  * the new log tail LEB number. Returns zero in case of success and a negative
 456  * error code in case of failure.
 457  */
 458 int ubifs_log_end_commit(struct ubifs_info *c, int ltail_lnum)
 459 {
 460         int err;
 461
 462         /*
 463          * At this phase we have to lock 'c->log_mutex' because UBIFS allows FS
 464          * writes during commit. Its only short "commit" start phase when
 465          * writers are blocked.
 466          */
 467         mutex_lock(&c->log_mutex);
 468
 469         dbg_log("old tail was LEB %d:0, new tail is LEB %d:0",
 470                 c->ltail_lnum, ltail_lnum);
 471
 472         c->ltail_lnum = ltail_lnum;
 473         /*
 474          * The commit is finished and from now on it must be guaranteed that
 475          * there is always enough space for the next commit.
 476          */
 477         c->min_log_bytes = c->leb_size;
 478
 479         spin_lock(&c->buds_lock);
 480         c->bud_bytes -= c->cmt_bud_bytes;
 481         spin_unlock(&c->buds_lock);
 482
 483         err = dbg_check_bud_bytes(c);
 484         if (err)
 485                 goto out;
 486
 487         err = ubifs_write_master(c);
 488
 489 out:
 490         mutex_unlock(&c->log_mutex);
 491         return err;
 492 }
 493
 494 /**
 495  * ubifs_log_post_commit - things to do after commit is completed.
 496  * @c: UBIFS file-system description object
 497  * @old_ltail_lnum: old log tail LEB number
 498  *
 499  * Release buds only after commit is completed, because they must be unchanged
 500  * if recovery is needed.
 501  *
 502  * Unmap log LEBs only after commit is completed, because they may be needed for
 503  * recovery.
 504  *
 505  * This function returns %0 on success and a negative error code on failure.
 506  */
 507 int ubifs_log_post_commit(struct ubifs_info *c, int old_ltail_lnum)
 508 {
 509         int lnum, err = 0;
 510
 511         while (!list_empty(&c->old_buds)) {
 512                 struct ubifs_bud *bud;
 513
 514                 bud = list_entry(c->old_buds.next, struct ubifs_bud, list);
 515                 err = ubifs_return_leb(c, bud->lnum);
 516                 if (err)
 517                         return err;
 518                 list_del(&bud->list);
 519                 kfree(bud);
 520         }
 521         mutex_lock(&c->log_mutex);
 522         for (lnum = old_ltail_lnum; lnum != c->ltail_lnum;
 523              lnum = ubifs_next_log_lnum(c, lnum)) {
 524                 dbg_log("unmap log LEB %d", lnum);
 525                 err = ubifs_leb_unmap(c, lnum);
 526                 if (err)
 527                         goto out;
 528         }
 529 out:
 530         mutex_unlock(&c->log_mutex);
 531         return err;
 532 }
 533
 534 /**
 535  * struct done_ref - references that have been done.
 536  * @rb: rb-tree node
 537  * @lnum: LEB number
 538  */
 539 struct done_ref {
 540         struct rb_node rb;
 541         int lnum;
 542 };
 543
 544 /**
 545  * done_already - determine if a reference has been done already.
 546  * @done_tree: rb-tree to store references that have been done
 547  * @lnum: LEB number of reference
 548  *
 549  * This function returns %1 if the reference has been done, %0 if not, otherwise
 550  * a negative error code is returned.
 551  */
 552 static int done_already(struct rb_root *done_tree, int lnum)
 553 {
 554         struct rb_node **p = &done_tree->rb_node, *parent = NULL;
 555         struct done_ref *dr;
 556
 557         while (*p) {
 558                 parent = *p;
 559                 dr = rb_entry(parent, struct done_ref, rb);
 560                 if (lnum < dr->lnum)
 561                         p = &(*p)->rb_left;
 562                 else if (lnum > dr->lnum)
 563                         p = &(*p)->rb_right;
 564                 else
 565                         return 1;
 566         }
 567
 568         dr = kzalloc(sizeof(struct done_ref), GFP_NOFS);
 569         if (!dr)
 570                 return -ENOMEM;
 571
 572         dr->lnum = lnum;
 573
 574         rb_link_node(&dr->rb, parent, p);
 575         rb_insert_color(&dr->rb, done_tree);
 576
 577         return 0;
 578 }
 579
 580 /**
 581  * destroy_done_tree - destroy the done tree.
 582  * @done_tree: done tree to destroy
 583  */
 584 static void destroy_done_tree(struct rb_root *done_tree)
 585 {
 586         struct done_ref *dr, *n;
 587
 588         rbtree_postorder_for_each_entry_safe(dr, n, done_tree, rb)
 589                 kfree(dr);
 590 }
 591
 592 /**
 593  * add_node - add a node to the consolidated log.
 594  * @c: UBIFS file-system description object
 595  * @buf: buffer to which to add
 596  * @lnum: LEB number to which to write is passed and returned here
 597  * @offs: offset to where to write is passed and returned here
 598  * @node: node to add
 599  *
 600  * This function returns %0 on success and a negative error code on failure.
 601  */
 602 static int add_node(struct ubifs_info *c, void *buf, int *lnum, int *offs,
 603                     void *node)
 604 {
 605         struct ubifs_ch *ch = node;
 606         int len = le32_to_cpu(ch->len), remains = c->leb_size - *offs;
 607
 608         if (len > remains) {
 609                 int sz = ALIGN(*offs, c->min_io_size), err;
 610
 611                 ubifs_pad(c, buf + *offs, sz - *offs);
 612                 err = ubifs_leb_change(c, *lnum, buf, sz);
 613                 if (err)
 614                         return err;
 615                 *lnum = ubifs_next_log_lnum(c, *lnum);
 616                 *offs = 0;
 617         }
 618         memcpy(buf + *offs, node, len);
 619         *offs += ALIGN(len, 8);
 620         return 0;
 621 }
 622
 623 /**
 624  * ubifs_consolidate_log - consolidate the log.
 625  * @c: UBIFS file-system description object
 626  *
 627  * Repeated failed commits could cause the log to be full, but at least 1 LEB is
 628  * needed for commit. This function rewrites the reference nodes in the log
 629  * omitting duplicates, and failed CS nodes, and leaving no gaps.
 630  *
 631  * This function returns %0 on success and a negative error code on failure.
 632  */
 633 int ubifs_consolidate_log(struct ubifs_info *c)
 634 {
 635         struct ubifs_scan_leb *sleb;
 636         struct ubifs_scan_node *snod;
 637         struct rb_root done_tree = RB_ROOT;
 638         int lnum, err, first = 1, write_lnum, offs = 0;
 639         void *buf;
 640
 641         dbg_rcvry("log tail LEB %d, log head LEB %d", c->ltail_lnum,
 642                   c->lhead_lnum);
 643         buf = vmalloc(c->leb_size);
 644         if (!buf)
 645                 return -ENOMEM;
 646         lnum = c->ltail_lnum;
 647         write_lnum = lnum;
 648         while (1) {
 649                 sleb = ubifs_scan(c, lnum, 0, c->sbuf, 0);
 650                 if (IS_ERR(sleb)) {
 651                         err = PTR_ERR(sleb);
 652                         goto out_free;
 653                 }
 654                 list_for_each_entry(snod, &sleb->nodes, list) {
 655                         switch (snod->type) {
 656                         case UBIFS_REF_NODE: {
 657                                 struct ubifs_ref_node *ref = snod->node;
 658                                 int ref_lnum = le32_to_cpu(ref->lnum);
 659
 660                                 err = done_already(&done_tree, ref_lnum);
 661                                 if (err < 0)
 662                                         goto out_scan;
 663                                 if (err != 1) {
 664                                         err = add_node(c, buf, &write_lnum,
 665                                                        &offs, snod->node);
 666                                         if (err)
 667                                                 goto out_scan;
 668                                 }
 669                                 break;
 670                         }
 671                         case UBIFS_CS_NODE:
 672                                 if (!first)
 673                                         break;
 674                                 err = add_node(c, buf, &write_lnum, &offs,
 675                                                snod->node);
 676                                 if (err)
 677                                         goto out_scan;
 678                                 first = 0;
 679                                 break;
 680                         }
 681                 }
 682                 ubifs_scan_destroy(sleb);
 683                 if (lnum == c->lhead_lnum)
 684                         break;
 685                 lnum = ubifs_next_log_lnum(c, lnum);
 686         }
 687         if (offs) {
 688                 int sz = ALIGN(offs, c->min_io_size);
 689
 690                 ubifs_pad(c, buf + offs, sz - offs);
 691                 err = ubifs_leb_change(c, write_lnum, buf, sz);
 692                 if (err)
 693                         goto out_free;
 694                 offs = ALIGN(offs, c->min_io_size);
 695         }
 696         destroy_done_tree(&done_tree);
 697         vfree(buf);
 698         if (write_lnum == c->lhead_lnum) {
 699                 ubifs_err(c, "log is too full");
 700                 return -EINVAL;
 701         }
 702         /* Unmap remaining LEBs */
 703         lnum = write_lnum;
 704         do {
 705                 lnum = ubifs_next_log_lnum(c, lnum);
 706                 err = ubifs_leb_unmap(c, lnum);
 707                 if (err)
 708                         return err;
 709         } while (lnum != c->lhead_lnum);
 710         c->lhead_lnum = write_lnum;
 711         c->lhead_offs = offs;
 712         dbg_rcvry("new log head at %d:%d", c->lhead_lnum, c->lhead_offs);
 713         return 0;
 714
 715 out_scan:
 716         ubifs_scan_destroy(sleb);
 717 out_free:
 718         destroy_done_tree(&done_tree);
 719         vfree(buf);
 720         return err;
 721 }
 722
 723 /**
 724  * dbg_check_bud_bytes - make sure bud bytes calculation are all right.
 725  * @c: UBIFS file-system description object
 726  *
 727  * This function makes sure the amount of flash space used by closed buds
 728  * ('c->bud_bytes' is correct). Returns zero in case of success and %-EINVAL in
 729  * case of failure.
 730  */
 731 static int dbg_check_bud_bytes(struct ubifs_info *c)
 732 {
 733         int i, err = 0;
 734         struct ubifs_bud *bud;
 735         long long bud_bytes = 0;
 736
 737         if (!dbg_is_chk_gen(c))
 738                 return 0;
 739
 740         spin_lock(&c->buds_lock);
 741         for (i = 0; i < c->jhead_cnt; i++)
 742                 list_for_each_entry(bud, &c->jheads[i].buds_list, list)
 743                         bud_bytes += c->leb_size - bud->start;
 744
 745         if (c->bud_bytes != bud_bytes) {
 746                 ubifs_err(c, "bad bud_bytes %lld, calculated %lld",
 747                           c->bud_bytes, bud_bytes);
 748                 err = -EINVAL;
 749         }
 750         spin_unlock(&c->buds_lock);
 751
 752         return err;
 753 }