linux/fs/ubifs/log.c
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   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
  32static 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 */
  42struct 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 */
  71struct 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 */
 102static 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
 112                return t - h;
 113}
 114
 115/**
 116 * ubifs_add_bud - add bud LEB to the tree of buds and its journal head list.
 117 * @c: UBIFS file-system description object
 118 * @bud: the bud to add
 119 */
 120void ubifs_add_bud(struct ubifs_info *c, struct ubifs_bud *bud)
 121{
 122        struct rb_node **p, *parent = NULL;
 123        struct ubifs_bud *b;
 124        struct ubifs_jhead *jhead;
 125
 126        spin_lock(&c->buds_lock);
 127        p = &c->buds.rb_node;
 128        while (*p) {
 129                parent = *p;
 130                b = rb_entry(parent, struct ubifs_bud, rb);
 131                ubifs_assert(bud->lnum != b->lnum);
 132                if (bud->lnum < b->lnum)
 133                        p = &(*p)->rb_left;
 134                else
 135                        p = &(*p)->rb_right;
 136        }
 137
 138        rb_link_node(&bud->rb, parent, p);
 139        rb_insert_color(&bud->rb, &c->buds);
 140        if (c->jheads) {
 141                jhead = &c->jheads[bud->jhead];
 142                list_add_tail(&bud->list, &jhead->buds_list);
 143        } else
 144                ubifs_assert(c->replaying && c->ro_mount);
 145
 146        /*
 147         * Note, although this is a new bud, we anyway account this space now,
 148         * before any data has been written to it, because this is about to
 149         * guarantee fixed mount time, and this bud will anyway be read and
 150         * scanned.
 151         */
 152        c->bud_bytes += c->leb_size - bud->start;
 153
 154        dbg_log("LEB %d:%d, jhead %s, bud_bytes %lld", bud->lnum,
 155                bud->start, dbg_jhead(bud->jhead), c->bud_bytes);
 156        spin_unlock(&c->buds_lock);
 157}
 158
 159/**
 160 * ubifs_add_bud_to_log - add a new bud to the log.
 161 * @c: UBIFS file-system description object
 162 * @jhead: journal head the bud belongs to
 163 * @lnum: LEB number of the bud
 164 * @offs: starting offset of the bud
 165 *
 166 * This function writes reference node for the new bud LEB @lnum it to the log,
 167 * and adds it to the buds tress. It also makes sure that log size does not
 168 * exceed the 'c->max_bud_bytes' limit. Returns zero in case of success,
 169 * %-EAGAIN if commit is required, and a negative error codes in case of
 170 * failure.
 171 */
 172int ubifs_add_bud_to_log(struct ubifs_info *c, int jhead, int lnum, int offs)
 173{
 174        int err;
 175        struct ubifs_bud *bud;
 176        struct ubifs_ref_node *ref;
 177
 178        bud = kmalloc(sizeof(struct ubifs_bud), GFP_NOFS);
 179        if (!bud)
 180                return -ENOMEM;
 181        ref = kzalloc(c->ref_node_alsz, GFP_NOFS);
 182        if (!ref) {
 183                kfree(bud);
 184                return -ENOMEM;
 185        }
 186
 187        mutex_lock(&c->log_mutex);
 188        ubifs_assert(!c->ro_media && !c->ro_mount);
 189        if (c->ro_error) {
 190                err = -EROFS;
 191                goto out_unlock;
 192        }
 193
 194        /* Make sure we have enough space in the log */
 195        if (empty_log_bytes(c) - c->ref_node_alsz < c->min_log_bytes) {
 196                dbg_log("not enough log space - %lld, required %d",
 197                        empty_log_bytes(c), c->min_log_bytes);
 198                ubifs_commit_required(c);
 199                err = -EAGAIN;
 200                goto out_unlock;
 201        }
 202
 203        /*
 204         * Make sure the amount of space in buds will not exceed the
 205         * 'c->max_bud_bytes' limit, because we want to guarantee mount time
 206         * limits.
 207         *
 208         * It is not necessary to hold @c->buds_lock when reading @c->bud_bytes
 209         * because we are holding @c->log_mutex. All @c->bud_bytes take place
 210         * when both @c->log_mutex and @c->bud_bytes are locked.
 211         */
 212        if (c->bud_bytes + c->leb_size - offs > c->max_bud_bytes) {
 213                dbg_log("bud bytes %lld (%lld max), require commit",
 214                        c->bud_bytes, c->max_bud_bytes);
 215                ubifs_commit_required(c);
 216                err = -EAGAIN;
 217                goto out_unlock;
 218        }
 219
 220        /*
 221         * If the journal is full enough - start background commit. Note, it is
 222         * OK to read 'c->cmt_state' without spinlock because integer reads
 223         * are atomic in the kernel.
 224         */
 225        if (c->bud_bytes >= c->bg_bud_bytes &&
 226            c->cmt_state == COMMIT_RESTING) {
 227                dbg_log("bud bytes %lld (%lld max), initiate BG commit",
 228                        c->bud_bytes, c->max_bud_bytes);
 229                ubifs_request_bg_commit(c);
 230        }
 231
 232        bud->lnum = lnum;
 233        bud->start = offs;
 234        bud->jhead = jhead;
 235
 236        ref->ch.node_type = UBIFS_REF_NODE;
 237        ref->lnum = cpu_to_le32(bud->lnum);
 238        ref->offs = cpu_to_le32(bud->start);
 239        ref->jhead = cpu_to_le32(jhead);
 240
 241        if (c->lhead_offs > c->leb_size - c->ref_node_alsz) {
 242                c->lhead_lnum = ubifs_next_log_lnum(c, c->lhead_lnum);
 243                c->lhead_offs = 0;
 244        }
 245
 246        if (c->lhead_offs == 0) {
 247                /* Must ensure next log LEB has been unmapped */
 248                err = ubifs_leb_unmap(c, c->lhead_lnum);
 249                if (err)
 250                        goto out_unlock;
 251        }
 252
 253        if (bud->start == 0) {
 254                /*
 255                 * Before writing the LEB reference which refers an empty LEB
 256                 * to the log, we have to make sure it is mapped, because
 257                 * otherwise we'd risk to refer an LEB with garbage in case of
 258                 * an unclean reboot, because the target LEB might have been
 259                 * unmapped, but not yet physically erased.
 260                 */
 261                err = ubifs_leb_map(c, bud->lnum);
 262                if (err)
 263                        goto out_unlock;
 264        }
 265
 266        dbg_log("write ref LEB %d:%d",
 267                c->lhead_lnum, c->lhead_offs);
 268        err = ubifs_write_node(c, ref, UBIFS_REF_NODE_SZ, c->lhead_lnum,
 269                               c->lhead_offs);
 270        if (err)
 271                goto out_unlock;
 272
 273        c->lhead_offs += c->ref_node_alsz;
 274
 275        ubifs_add_bud(c, bud);
 276
 277        mutex_unlock(&c->log_mutex);
 278        kfree(ref);
 279        return 0;
 280
 281out_unlock:
 282        mutex_unlock(&c->log_mutex);
 283        kfree(ref);
 284        kfree(bud);
 285        return err;
 286}
 287
 288/**
 289 * remove_buds - remove used buds.
 290 * @c: UBIFS file-system description object
 291 *
 292 * This function removes use buds from the buds tree. It does not remove the
 293 * buds which are pointed to by journal heads.
 294 */
 295static void remove_buds(struct ubifs_info *c)
 296{
 297        struct rb_node *p;
 298
 299        ubifs_assert(list_empty(&c->old_buds));
 300        c->cmt_bud_bytes = 0;
 301        spin_lock(&c->buds_lock);
 302        p = rb_first(&c->buds);
 303        while (p) {
 304                struct rb_node *p1 = p;
 305                struct ubifs_bud *bud;
 306                struct ubifs_wbuf *wbuf;
 307
 308                p = rb_next(p);
 309                bud = rb_entry(p1, struct ubifs_bud, rb);
 310                wbuf = &c->jheads[bud->jhead].wbuf;
 311
 312                if (wbuf->lnum == bud->lnum) {
 313                        /*
 314                         * Do not remove buds which are pointed to by journal
 315                         * heads (non-closed buds).
 316                         */
 317                        c->cmt_bud_bytes += wbuf->offs - bud->start;
 318                        dbg_log("preserve %d:%d, jhead %s, bud bytes %d, "
 319                                "cmt_bud_bytes %lld", bud->lnum, bud->start,
 320                                dbg_jhead(bud->jhead), wbuf->offs - bud->start,
 321                                c->cmt_bud_bytes);
 322                        bud->start = wbuf->offs;
 323                } else {
 324                        c->cmt_bud_bytes += c->leb_size - bud->start;
 325                        dbg_log("remove %d:%d, jhead %s, bud bytes %d, "
 326                                "cmt_bud_bytes %lld", bud->lnum, bud->start,
 327                                dbg_jhead(bud->jhead), c->leb_size - bud->start,
 328                                c->cmt_bud_bytes);
 329                        rb_erase(p1, &c->buds);
 330                        /*
 331                         * If the commit does not finish, the recovery will need
 332                         * to replay the journal, in which case the old buds
 333                         * must be unchanged. Do not release them until post
 334                         * commit i.e. do not allow them to be garbage
 335                         * collected.
 336                         */
 337                        list_move(&bud->list, &c->old_buds);
 338                }
 339        }
 340        spin_unlock(&c->buds_lock);
 341}
 342
 343/**
 344 * ubifs_log_start_commit - start commit.
 345 * @c: UBIFS file-system description object
 346 * @ltail_lnum: return new log tail LEB number
 347 *
 348 * The commit operation starts with writing "commit start" node to the log and
 349 * reference nodes for all journal heads which will define new journal after
 350 * the commit has been finished. The commit start and reference nodes are
 351 * written in one go to the nearest empty log LEB (hence, when commit is
 352 * finished UBIFS may safely unmap all the previous log LEBs). This function
 353 * returns zero in case of success and a negative error code in case of
 354 * failure.
 355 */
 356int ubifs_log_start_commit(struct ubifs_info *c, int *ltail_lnum)
 357{
 358        void *buf;
 359        struct ubifs_cs_node *cs;
 360        struct ubifs_ref_node *ref;
 361        int err, i, max_len, len;
 362
 363        err = dbg_check_bud_bytes(c);
 364        if (err)
 365                return err;
 366
 367        max_len = UBIFS_CS_NODE_SZ + c->jhead_cnt * UBIFS_REF_NODE_SZ;
 368        max_len = ALIGN(max_len, c->min_io_size);
 369        buf = cs = kmalloc(max_len, GFP_NOFS);
 370        if (!buf)
 371                return -ENOMEM;
 372
 373        cs->ch.node_type = UBIFS_CS_NODE;
 374        cs->cmt_no = cpu_to_le64(c->cmt_no);
 375        ubifs_prepare_node(c, cs, UBIFS_CS_NODE_SZ, 0);
 376
 377        /*
 378         * Note, we do not lock 'c->log_mutex' because this is the commit start
 379         * phase and we are exclusively using the log. And we do not lock
 380         * write-buffer because nobody can write to the file-system at this
 381         * phase.
 382         */
 383
 384        len = UBIFS_CS_NODE_SZ;
 385        for (i = 0; i < c->jhead_cnt; i++) {
 386                int lnum = c->jheads[i].wbuf.lnum;
 387                int offs = c->jheads[i].wbuf.offs;
 388
 389                if (lnum == -1 || offs == c->leb_size)
 390                        continue;
 391
 392                dbg_log("add ref to LEB %d:%d for jhead %s",
 393                        lnum, offs, dbg_jhead(i));
 394                ref = buf + len;
 395                ref->ch.node_type = UBIFS_REF_NODE;
 396                ref->lnum = cpu_to_le32(lnum);
 397                ref->offs = cpu_to_le32(offs);
 398                ref->jhead = cpu_to_le32(i);
 399
 400                ubifs_prepare_node(c, ref, UBIFS_REF_NODE_SZ, 0);
 401                len += UBIFS_REF_NODE_SZ;
 402        }
 403
 404        ubifs_pad(c, buf + len, ALIGN(len, c->min_io_size) - len);
 405
 406        /* Switch to the next log LEB */
 407        if (c->lhead_offs) {
 408                c->lhead_lnum = ubifs_next_log_lnum(c, c->lhead_lnum);
 409                c->lhead_offs = 0;
 410        }
 411
 412        if (c->lhead_offs == 0) {
 413                /* Must ensure next LEB has been unmapped */
 414                err = ubifs_leb_unmap(c, c->lhead_lnum);
 415                if (err)
 416                        goto out;
 417        }
 418
 419        len = ALIGN(len, c->min_io_size);
 420        dbg_log("writing commit start at LEB %d:0, len %d", c->lhead_lnum, len);
 421        err = ubifs_leb_write(c, c->lhead_lnum, cs, 0, len);
 422        if (err)
 423                goto out;
 424
 425        *ltail_lnum = c->lhead_lnum;
 426
 427        c->lhead_offs += len;
 428        if (c->lhead_offs == c->leb_size) {
 429                c->lhead_lnum = ubifs_next_log_lnum(c, c->lhead_lnum);
 430                c->lhead_offs = 0;
 431        }
 432
 433        remove_buds(c);
 434
 435        /*
 436         * We have started the commit and now users may use the rest of the log
 437         * for new writes.
 438         */
 439        c->min_log_bytes = 0;
 440
 441out:
 442        kfree(buf);
 443        return err;
 444}
 445
 446/**
 447 * ubifs_log_end_commit - end commit.
 448 * @c: UBIFS file-system description object
 449 * @ltail_lnum: new log tail LEB number
 450 *
 451 * This function is called on when the commit operation was finished. It
 452 * moves log tail to new position and unmaps LEBs which contain obsolete data.
 453 * Returns zero in case of success and a negative error code in case of
 454 * failure.
 455 */
 456int ubifs_log_end_commit(struct ubifs_info *c, int ltail_lnum)
 457{
 458        int err;
 459
 460        /*
 461         * At this phase we have to lock 'c->log_mutex' because UBIFS allows FS
 462         * writes during commit. Its only short "commit" start phase when
 463         * writers are blocked.
 464         */
 465        mutex_lock(&c->log_mutex);
 466
 467        dbg_log("old tail was LEB %d:0, new tail is LEB %d:0",
 468                c->ltail_lnum, ltail_lnum);
 469
 470        c->ltail_lnum = ltail_lnum;
 471        /*
 472         * The commit is finished and from now on it must be guaranteed that
 473         * there is always enough space for the next commit.
 474         */
 475        c->min_log_bytes = c->leb_size;
 476
 477        spin_lock(&c->buds_lock);
 478        c->bud_bytes -= c->cmt_bud_bytes;
 479        spin_unlock(&c->buds_lock);
 480
 481        err = dbg_check_bud_bytes(c);
 482
 483        mutex_unlock(&c->log_mutex);
 484        return err;
 485}
 486
 487/**
 488 * ubifs_log_post_commit - things to do after commit is completed.
 489 * @c: UBIFS file-system description object
 490 * @old_ltail_lnum: old log tail LEB number
 491 *
 492 * Release buds only after commit is completed, because they must be unchanged
 493 * if recovery is needed.
 494 *
 495 * Unmap log LEBs only after commit is completed, because they may be needed for
 496 * recovery.
 497 *
 498 * This function returns %0 on success and a negative error code on failure.
 499 */
 500int ubifs_log_post_commit(struct ubifs_info *c, int old_ltail_lnum)
 501{
 502        int lnum, err = 0;
 503
 504        while (!list_empty(&c->old_buds)) {
 505                struct ubifs_bud *bud;
 506
 507                bud = list_entry(c->old_buds.next, struct ubifs_bud, list);
 508                err = ubifs_return_leb(c, bud->lnum);
 509                if (err)
 510                        return err;
 511                list_del(&bud->list);
 512                kfree(bud);
 513        }
 514        mutex_lock(&c->log_mutex);
 515        for (lnum = old_ltail_lnum; lnum != c->ltail_lnum;
 516             lnum = ubifs_next_log_lnum(c, lnum)) {
 517                dbg_log("unmap log LEB %d", lnum);
 518                err = ubifs_leb_unmap(c, lnum);
 519                if (err)
 520                        goto out;
 521        }
 522out:
 523        mutex_unlock(&c->log_mutex);
 524        return err;
 525}
 526
 527/**
 528 * struct done_ref - references that have been done.
 529 * @rb: rb-tree node
 530 * @lnum: LEB number
 531 */
 532struct done_ref {
 533        struct rb_node rb;
 534        int lnum;
 535};
 536
 537/**
 538 * done_already - determine if a reference has been done already.
 539 * @done_tree: rb-tree to store references that have been done
 540 * @lnum: LEB number of reference
 541 *
 542 * This function returns %1 if the reference has been done, %0 if not, otherwise
 543 * a negative error code is returned.
 544 */
 545static int done_already(struct rb_root *done_tree, int lnum)
 546{
 547        struct rb_node **p = &done_tree->rb_node, *parent = NULL;
 548        struct done_ref *dr;
 549
 550        while (*p) {
 551                parent = *p;
 552                dr = rb_entry(parent, struct done_ref, rb);
 553                if (lnum < dr->lnum)
 554                        p = &(*p)->rb_left;
 555                else if (lnum > dr->lnum)
 556                        p = &(*p)->rb_right;
 557                else
 558                        return 1;
 559        }
 560
 561        dr = kzalloc(sizeof(struct done_ref), GFP_NOFS);
 562        if (!dr)
 563                return -ENOMEM;
 564
 565        dr->lnum = lnum;
 566
 567        rb_link_node(&dr->rb, parent, p);
 568        rb_insert_color(&dr->rb, done_tree);
 569
 570        return 0;
 571}
 572
 573/**
 574 * destroy_done_tree - destroy the done tree.
 575 * @done_tree: done tree to destroy
 576 */
 577static void destroy_done_tree(struct rb_root *done_tree)
 578{
 579        struct rb_node *this = done_tree->rb_node;
 580        struct done_ref *dr;
 581
 582        while (this) {
 583                if (this->rb_left) {
 584                        this = this->rb_left;
 585                        continue;
 586                } else if (this->rb_right) {
 587                        this = this->rb_right;
 588                        continue;
 589                }
 590                dr = rb_entry(this, struct done_ref, rb);
 591                this = rb_parent(this);
 592                if (this) {
 593                        if (this->rb_left == &dr->rb)
 594                                this->rb_left = NULL;
 595                        else
 596                                this->rb_right = NULL;
 597                }
 598                kfree(dr);
 599        }
 600}
 601
 602/**
 603 * add_node - add a node to the consolidated log.
 604 * @c: UBIFS file-system description object
 605 * @buf: buffer to which to add
 606 * @lnum: LEB number to which to write is passed and returned here
 607 * @offs: offset to where to write is passed and returned here
 608 * @node: node to add
 609 *
 610 * This function returns %0 on success and a negative error code on failure.
 611 */
 612static int add_node(struct ubifs_info *c, void *buf, int *lnum, int *offs,
 613                    void *node)
 614{
 615        struct ubifs_ch *ch = node;
 616        int len = le32_to_cpu(ch->len), remains = c->leb_size - *offs;
 617
 618        if (len > remains) {
 619                int sz = ALIGN(*offs, c->min_io_size), err;
 620
 621                ubifs_pad(c, buf + *offs, sz - *offs);
 622                err = ubifs_leb_change(c, *lnum, buf, sz);
 623                if (err)
 624                        return err;
 625                *lnum = ubifs_next_log_lnum(c, *lnum);
 626                *offs = 0;
 627        }
 628        memcpy(buf + *offs, node, len);
 629        *offs += ALIGN(len, 8);
 630        return 0;
 631}
 632
 633/**
 634 * ubifs_consolidate_log - consolidate the log.
 635 * @c: UBIFS file-system description object
 636 *
 637 * Repeated failed commits could cause the log to be full, but at least 1 LEB is
 638 * needed for commit. This function rewrites the reference nodes in the log
 639 * omitting duplicates, and failed CS nodes, and leaving no gaps.
 640 *
 641 * This function returns %0 on success and a negative error code on failure.
 642 */
 643int ubifs_consolidate_log(struct ubifs_info *c)
 644{
 645        struct ubifs_scan_leb *sleb;
 646        struct ubifs_scan_node *snod;
 647        struct rb_root done_tree = RB_ROOT;
 648        int lnum, err, first = 1, write_lnum, offs = 0;
 649        void *buf;
 650
 651        dbg_rcvry("log tail LEB %d, log head LEB %d", c->ltail_lnum,
 652                  c->lhead_lnum);
 653        buf = vmalloc(c->leb_size);
 654        if (!buf)
 655                return -ENOMEM;
 656        lnum = c->ltail_lnum;
 657        write_lnum = lnum;
 658        while (1) {
 659                sleb = ubifs_scan(c, lnum, 0, c->sbuf, 0);
 660                if (IS_ERR(sleb)) {
 661                        err = PTR_ERR(sleb);
 662                        goto out_free;
 663                }
 664                list_for_each_entry(snod, &sleb->nodes, list) {
 665                        switch (snod->type) {
 666                        case UBIFS_REF_NODE: {
 667                                struct ubifs_ref_node *ref = snod->node;
 668                                int ref_lnum = le32_to_cpu(ref->lnum);
 669
 670                                err = done_already(&done_tree, ref_lnum);
 671                                if (err < 0)
 672                                        goto out_scan;
 673                                if (err != 1) {
 674                                        err = add_node(c, buf, &write_lnum,
 675                                                       &offs, snod->node);
 676                                        if (err)
 677                                                goto out_scan;
 678                                }
 679                                break;
 680                        }
 681                        case UBIFS_CS_NODE:
 682                                if (!first)
 683                                        break;
 684                                err = add_node(c, buf, &write_lnum, &offs,
 685                                               snod->node);
 686                                if (err)
 687                                        goto out_scan;
 688                                first = 0;
 689                                break;
 690                        }
 691                }
 692                ubifs_scan_destroy(sleb);
 693                if (lnum == c->lhead_lnum)
 694                        break;
 695                lnum = ubifs_next_log_lnum(c, lnum);
 696        }
 697        if (offs) {
 698                int sz = ALIGN(offs, c->min_io_size);
 699
 700                ubifs_pad(c, buf + offs, sz - offs);
 701                err = ubifs_leb_change(c, write_lnum, buf, sz);
 702                if (err)
 703                        goto out_free;
 704                offs = ALIGN(offs, c->min_io_size);
 705        }
 706        destroy_done_tree(&done_tree);
 707        vfree(buf);
 708        if (write_lnum == c->lhead_lnum) {
 709                ubifs_err("log is too full");
 710                return -EINVAL;
 711        }
 712        /* Unmap remaining LEBs */
 713        lnum = write_lnum;
 714        do {
 715                lnum = ubifs_next_log_lnum(c, lnum);
 716                err = ubifs_leb_unmap(c, lnum);
 717                if (err)
 718                        return err;
 719        } while (lnum != c->lhead_lnum);
 720        c->lhead_lnum = write_lnum;
 721        c->lhead_offs = offs;
 722        dbg_rcvry("new log head at %d:%d", c->lhead_lnum, c->lhead_offs);
 723        return 0;
 724
 725out_scan:
 726        ubifs_scan_destroy(sleb);
 727out_free:
 728        destroy_done_tree(&done_tree);
 729        vfree(buf);
 730        return err;
 731}
 732
 733/**
 734 * dbg_check_bud_bytes - make sure bud bytes calculation are all right.
 735 * @c: UBIFS file-system description object
 736 *
 737 * This function makes sure the amount of flash space used by closed buds
 738 * ('c->bud_bytes' is correct). Returns zero in case of success and %-EINVAL in
 739 * case of failure.
 740 */
 741static int dbg_check_bud_bytes(struct ubifs_info *c)
 742{
 743        int i, err = 0;
 744        struct ubifs_bud *bud;
 745        long long bud_bytes = 0;
 746
 747        if (!dbg_is_chk_gen(c))
 748                return 0;
 749
 750        spin_lock(&c->buds_lock);
 751        for (i = 0; i < c->jhead_cnt; i++)
 752                list_for_each_entry(bud, &c->jheads[i].buds_list, list)
 753                        bud_bytes += c->leb_size - bud->start;
 754
 755        if (c->bud_bytes != bud_bytes) {
 756                ubifs_err("bad bud_bytes %lld, calculated %lld",
 757                          c->bud_bytes, bud_bytes);
 758                err = -EINVAL;
 759        }
 760        spin_unlock(&c->buds_lock);
 761
 762        return err;
 763}
 764
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