linux/fs/ubifs/commit.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: Adrian Hunter
  20 *          Artem Bityutskiy (\xD0\x91\xD0\xB8\xD1\x82\xD1\x8E\xD1\x86\xD0\xBA\xD0\xB8\xD0\xB9 \xD0\x90\xD1\x80\xD1\x82\xD1\x91\xD0\xBC)
  21 */
  22
  23/*
  24 * This file implements functions that manage the running of the commit process.
  25 * Each affected module has its own functions to accomplish their part in the
  26 * commit and those functions are called here.
  27 *
  28 * The commit is the process whereby all updates to the index and LEB properties
  29 * are written out together and the journal becomes empty. This keeps the
  30 * file system consistent - at all times the state can be recreated by reading
  31 * the index and LEB properties and then replaying the journal.
  32 *
  33 * The commit is split into two parts named "commit start" and "commit end".
  34 * During commit start, the commit process has exclusive access to the journal
  35 * by holding the commit semaphore down for writing. As few I/O operations as
  36 * possible are performed during commit start, instead the nodes that are to be
  37 * written are merely identified. During commit end, the commit semaphore is no
  38 * longer held and the journal is again in operation, allowing users to continue
  39 * to use the file system while the bulk of the commit I/O is performed. The
  40 * purpose of this two-step approach is to prevent the commit from causing any
  41 * latency blips. Note that in any case, the commit does not prevent lookups
  42 * (as permitted by the TNC mutex), or access to VFS data structures e.g. page
  43 * cache.
  44 */
  45
  46#include <linux/freezer.h>
  47#include <linux/kthread.h>
  48#include <linux/slab.h>
  49#include "ubifs.h"
  50
  51/**
  52 * do_commit - commit the journal.
  53 * @c: UBIFS file-system description object
  54 *
  55 * This function implements UBIFS commit. It has to be called with commit lock
  56 * locked. Returns zero in case of success and a negative error code in case of
  57 * failure.
  58 */
  59static int do_commit(struct ubifs_info *c)
  60{
  61        int err, new_ltail_lnum, old_ltail_lnum, i;
  62        struct ubifs_zbranch zroot;
  63        struct ubifs_lp_stats lst;
  64
  65        dbg_cmt("start");
  66        ubifs_assert(!c->ro_media && !c->ro_mount);
  67
  68        if (c->ro_error) {
  69                err = -EROFS;
  70                goto out_up;
  71        }
  72
  73        /* Sync all write buffers (necessary for recovery) */
  74        for (i = 0; i < c->jhead_cnt; i++) {
  75                err = ubifs_wbuf_sync(&c->jheads[i].wbuf);
  76                if (err)
  77                        goto out_up;
  78        }
  79
  80        c->cmt_no += 1;
  81        err = ubifs_gc_start_commit(c);
  82        if (err)
  83                goto out_up;
  84        err = dbg_check_lprops(c);
  85        if (err)
  86                goto out_up;
  87        err = ubifs_log_start_commit(c, &new_ltail_lnum);
  88        if (err)
  89                goto out_up;
  90        err = ubifs_tnc_start_commit(c, &zroot);
  91        if (err)
  92                goto out_up;
  93        err = ubifs_lpt_start_commit(c);
  94        if (err)
  95                goto out_up;
  96        err = ubifs_orphan_start_commit(c);
  97        if (err)
  98                goto out_up;
  99
 100        ubifs_get_lp_stats(c, &lst);
 101
 102        up_write(&c->commit_sem);
 103
 104        err = ubifs_tnc_end_commit(c);
 105        if (err)
 106                goto out;
 107        err = ubifs_lpt_end_commit(c);
 108        if (err)
 109                goto out;
 110        err = ubifs_orphan_end_commit(c);
 111        if (err)
 112                goto out;
 113        old_ltail_lnum = c->ltail_lnum;
 114        err = ubifs_log_end_commit(c, new_ltail_lnum);
 115        if (err)
 116                goto out;
 117        err = dbg_check_old_index(c, &zroot);
 118        if (err)
 119                goto out;
 120
 121        mutex_lock(&c->mst_mutex);
 122        c->mst_node->cmt_no      = cpu_to_le64(c->cmt_no);
 123        c->mst_node->log_lnum    = cpu_to_le32(new_ltail_lnum);
 124        c->mst_node->root_lnum   = cpu_to_le32(zroot.lnum);
 125        c->mst_node->root_offs   = cpu_to_le32(zroot.offs);
 126        c->mst_node->root_len    = cpu_to_le32(zroot.len);
 127        c->mst_node->ihead_lnum  = cpu_to_le32(c->ihead_lnum);
 128        c->mst_node->ihead_offs  = cpu_to_le32(c->ihead_offs);
 129        c->mst_node->index_size  = cpu_to_le64(c->old_idx_sz);
 130        c->mst_node->lpt_lnum    = cpu_to_le32(c->lpt_lnum);
 131        c->mst_node->lpt_offs    = cpu_to_le32(c->lpt_offs);
 132        c->mst_node->nhead_lnum  = cpu_to_le32(c->nhead_lnum);
 133        c->mst_node->nhead_offs  = cpu_to_le32(c->nhead_offs);
 134        c->mst_node->ltab_lnum   = cpu_to_le32(c->ltab_lnum);
 135        c->mst_node->ltab_offs   = cpu_to_le32(c->ltab_offs);
 136        c->mst_node->lsave_lnum  = cpu_to_le32(c->lsave_lnum);
 137        c->mst_node->lsave_offs  = cpu_to_le32(c->lsave_offs);
 138        c->mst_node->lscan_lnum  = cpu_to_le32(c->lscan_lnum);
 139        c->mst_node->empty_lebs  = cpu_to_le32(lst.empty_lebs);
 140        c->mst_node->idx_lebs    = cpu_to_le32(lst.idx_lebs);
 141        c->mst_node->total_free  = cpu_to_le64(lst.total_free);
 142        c->mst_node->total_dirty = cpu_to_le64(lst.total_dirty);
 143        c->mst_node->total_used  = cpu_to_le64(lst.total_used);
 144        c->mst_node->total_dead  = cpu_to_le64(lst.total_dead);
 145        c->mst_node->total_dark  = cpu_to_le64(lst.total_dark);
 146        if (c->no_orphs)
 147                c->mst_node->flags |= cpu_to_le32(UBIFS_MST_NO_ORPHS);
 148        else
 149                c->mst_node->flags &= ~cpu_to_le32(UBIFS_MST_NO_ORPHS);
 150        err = ubifs_write_master(c);
 151        mutex_unlock(&c->mst_mutex);
 152        if (err)
 153                goto out;
 154
 155        err = ubifs_log_post_commit(c, old_ltail_lnum);
 156        if (err)
 157                goto out;
 158        err = ubifs_gc_end_commit(c);
 159        if (err)
 160                goto out;
 161        err = ubifs_lpt_post_commit(c);
 162        if (err)
 163                goto out;
 164
 165        spin_lock(&c->cs_lock);
 166        c->cmt_state = COMMIT_RESTING;
 167        wake_up(&c->cmt_wq);
 168        dbg_cmt("commit end");
 169        spin_unlock(&c->cs_lock);
 170
 171        return 0;
 172
 173out_up:
 174        up_write(&c->commit_sem);
 175out:
 176        ubifs_err("commit failed, error %d", err);
 177        spin_lock(&c->cs_lock);
 178        c->cmt_state = COMMIT_BROKEN;
 179        wake_up(&c->cmt_wq);
 180        spin_unlock(&c->cs_lock);
 181        ubifs_ro_mode(c, err);
 182        return err;
 183}
 184
 185/**
 186 * run_bg_commit - run background commit if it is needed.
 187 * @c: UBIFS file-system description object
 188 *
 189 * This function runs background commit if it is needed. Returns zero in case
 190 * of success and a negative error code in case of failure.
 191 */
 192static int run_bg_commit(struct ubifs_info *c)
 193{
 194        spin_lock(&c->cs_lock);
 195        /*
 196         * Run background commit only if background commit was requested or if
 197         * commit is required.
 198         */
 199        if (c->cmt_state != COMMIT_BACKGROUND &&
 200            c->cmt_state != COMMIT_REQUIRED)
 201                goto out;
 202        spin_unlock(&c->cs_lock);
 203
 204        down_write(&c->commit_sem);
 205        spin_lock(&c->cs_lock);
 206        if (c->cmt_state == COMMIT_REQUIRED)
 207                c->cmt_state = COMMIT_RUNNING_REQUIRED;
 208        else if (c->cmt_state == COMMIT_BACKGROUND)
 209                c->cmt_state = COMMIT_RUNNING_BACKGROUND;
 210        else
 211                goto out_cmt_unlock;
 212        spin_unlock(&c->cs_lock);
 213
 214        return do_commit(c);
 215
 216out_cmt_unlock:
 217        up_write(&c->commit_sem);
 218out:
 219        spin_unlock(&c->cs_lock);
 220        return 0;
 221}
 222
 223/**
 224 * ubifs_bg_thread - UBIFS background thread function.
 225 * @info: points to the file-system description object
 226 *
 227 * This function implements various file-system background activities:
 228 * o when a write-buffer timer expires it synchronizes the appropriate
 229 *   write-buffer;
 230 * o when the journal is about to be full, it starts in-advance commit.
 231 *
 232 * Note, other stuff like background garbage collection may be added here in
 233 * future.
 234 */
 235int ubifs_bg_thread(void *info)
 236{
 237        int err;
 238        struct ubifs_info *c = info;
 239
 240        dbg_msg("background thread \"%s\" started, PID %d",
 241                c->bgt_name, current->pid);
 242        set_freezable();
 243
 244        while (1) {
 245                if (kthread_should_stop())
 246                        break;
 247
 248                if (try_to_freeze())
 249                        continue;
 250
 251                set_current_state(TASK_INTERRUPTIBLE);
 252                /* Check if there is something to do */
 253                if (!c->need_bgt) {
 254                        /*
 255                         * Nothing prevents us from going sleep now and
 256                         * be never woken up and block the task which
 257                         * could wait in 'kthread_stop()' forever.
 258                         */
 259                        if (kthread_should_stop())
 260                                break;
 261                        schedule();
 262                        continue;
 263                } else
 264                        __set_current_state(TASK_RUNNING);
 265
 266                c->need_bgt = 0;
 267                err = ubifs_bg_wbufs_sync(c);
 268                if (err)
 269                        ubifs_ro_mode(c, err);
 270
 271                run_bg_commit(c);
 272                cond_resched();
 273        }
 274
 275        dbg_msg("background thread \"%s\" stops", c->bgt_name);
 276        return 0;
 277}
 278
 279/**
 280 * ubifs_commit_required - set commit state to "required".
 281 * @c: UBIFS file-system description object
 282 *
 283 * This function is called if a commit is required but cannot be done from the
 284 * calling function, so it is just flagged instead.
 285 */
 286void ubifs_commit_required(struct ubifs_info *c)
 287{
 288        spin_lock(&c->cs_lock);
 289        switch (c->cmt_state) {
 290        case COMMIT_RESTING:
 291        case COMMIT_BACKGROUND:
 292                dbg_cmt("old: %s, new: %s", dbg_cstate(c->cmt_state),
 293                        dbg_cstate(COMMIT_REQUIRED));
 294                c->cmt_state = COMMIT_REQUIRED;
 295                break;
 296        case COMMIT_RUNNING_BACKGROUND:
 297                dbg_cmt("old: %s, new: %s", dbg_cstate(c->cmt_state),
 298                        dbg_cstate(COMMIT_RUNNING_REQUIRED));
 299                c->cmt_state = COMMIT_RUNNING_REQUIRED;
 300                break;
 301        case COMMIT_REQUIRED:
 302        case COMMIT_RUNNING_REQUIRED:
 303        case COMMIT_BROKEN:
 304                break;
 305        }
 306        spin_unlock(&c->cs_lock);
 307}
 308
 309/**
 310 * ubifs_request_bg_commit - notify the background thread to do a commit.
 311 * @c: UBIFS file-system description object
 312 *
 313 * This function is called if the journal is full enough to make a commit
 314 * worthwhile, so background thread is kicked to start it.
 315 */
 316void ubifs_request_bg_commit(struct ubifs_info *c)
 317{
 318        spin_lock(&c->cs_lock);
 319        if (c->cmt_state == COMMIT_RESTING) {
 320                dbg_cmt("old: %s, new: %s", dbg_cstate(c->cmt_state),
 321                        dbg_cstate(COMMIT_BACKGROUND));
 322                c->cmt_state = COMMIT_BACKGROUND;
 323                spin_unlock(&c->cs_lock);
 324                ubifs_wake_up_bgt(c);
 325        } else
 326                spin_unlock(&c->cs_lock);
 327}
 328
 329/**
 330 * wait_for_commit - wait for commit.
 331 * @c: UBIFS file-system description object
 332 *
 333 * This function sleeps until the commit operation is no longer running.
 334 */
 335static int wait_for_commit(struct ubifs_info *c)
 336{
 337        dbg_cmt("pid %d goes sleep", current->pid);
 338
 339        /*
 340         * The following sleeps if the condition is false, and will be woken
 341         * when the commit ends. It is possible, although very unlikely, that we
 342         * will wake up and see the subsequent commit running, rather than the
 343         * one we were waiting for, and go back to sleep.  However, we will be
 344         * woken again, so there is no danger of sleeping forever.
 345         */
 346        wait_event(c->cmt_wq, c->cmt_state != COMMIT_RUNNING_BACKGROUND &&
 347                              c->cmt_state != COMMIT_RUNNING_REQUIRED);
 348        dbg_cmt("commit finished, pid %d woke up", current->pid);
 349        return 0;
 350}
 351
 352/**
 353 * ubifs_run_commit - run or wait for commit.
 354 * @c: UBIFS file-system description object
 355 *
 356 * This function runs commit and returns zero in case of success and a negative
 357 * error code in case of failure.
 358 */
 359int ubifs_run_commit(struct ubifs_info *c)
 360{
 361        int err = 0;
 362
 363        spin_lock(&c->cs_lock);
 364        if (c->cmt_state == COMMIT_BROKEN) {
 365                err = -EINVAL;
 366                goto out;
 367        }
 368
 369        if (c->cmt_state == COMMIT_RUNNING_BACKGROUND)
 370                /*
 371                 * We set the commit state to 'running required' to indicate
 372                 * that we want it to complete as quickly as possible.
 373                 */
 374                c->cmt_state = COMMIT_RUNNING_REQUIRED;
 375
 376        if (c->cmt_state == COMMIT_RUNNING_REQUIRED) {
 377                spin_unlock(&c->cs_lock);
 378                return wait_for_commit(c);
 379        }
 380        spin_unlock(&c->cs_lock);
 381
 382        /* Ok, the commit is indeed needed */
 383
 384        down_write(&c->commit_sem);
 385        spin_lock(&c->cs_lock);
 386        /*
 387         * Since we unlocked 'c->cs_lock', the state may have changed, so
 388         * re-check it.
 389         */
 390        if (c->cmt_state == COMMIT_BROKEN) {
 391                err = -EINVAL;
 392                goto out_cmt_unlock;
 393        }
 394
 395        if (c->cmt_state == COMMIT_RUNNING_BACKGROUND)
 396                c->cmt_state = COMMIT_RUNNING_REQUIRED;
 397
 398        if (c->cmt_state == COMMIT_RUNNING_REQUIRED) {
 399                up_write(&c->commit_sem);
 400                spin_unlock(&c->cs_lock);
 401                return wait_for_commit(c);
 402        }
 403        c->cmt_state = COMMIT_RUNNING_REQUIRED;
 404        spin_unlock(&c->cs_lock);
 405
 406        err = do_commit(c);
 407        return err;
 408
 409out_cmt_unlock:
 410        up_write(&c->commit_sem);
 411out:
 412        spin_unlock(&c->cs_lock);
 413        return err;
 414}
 415
 416/**
 417 * ubifs_gc_should_commit - determine if it is time for GC to run commit.
 418 * @c: UBIFS file-system description object
 419 *
 420 * This function is called by garbage collection to determine if commit should
 421 * be run. If commit state is @COMMIT_BACKGROUND, which means that the journal
 422 * is full enough to start commit, this function returns true. It is not
 423 * absolutely necessary to commit yet, but it feels like this should be better
 424 * then to keep doing GC. This function returns %1 if GC has to initiate commit
 425 * and %0 if not.
 426 */
 427int ubifs_gc_should_commit(struct ubifs_info *c)
 428{
 429        int ret = 0;
 430
 431        spin_lock(&c->cs_lock);
 432        if (c->cmt_state == COMMIT_BACKGROUND) {
 433                dbg_cmt("commit required now");
 434                c->cmt_state = COMMIT_REQUIRED;
 435        } else
 436                dbg_cmt("commit not requested");
 437        if (c->cmt_state == COMMIT_REQUIRED)
 438                ret = 1;
 439        spin_unlock(&c->cs_lock);
 440        return ret;
 441}
 442
 443#ifdef CONFIG_UBIFS_FS_DEBUG
 444
 445/**
 446 * struct idx_node - hold index nodes during index tree traversal.
 447 * @list: list
 448 * @iip: index in parent (slot number of this indexing node in the parent
 449 *       indexing node)
 450 * @upper_key: all keys in this indexing node have to be less or equivalent to
 451 *             this key
 452 * @idx: index node (8-byte aligned because all node structures must be 8-byte
 453 *       aligned)
 454 */
 455struct idx_node {
 456        struct list_head list;
 457        int iip;
 458        union ubifs_key upper_key;
 459        struct ubifs_idx_node idx __attribute__((aligned(8)));
 460};
 461
 462/**
 463 * dbg_old_index_check_init - get information for the next old index check.
 464 * @c: UBIFS file-system description object
 465 * @zroot: root of the index
 466 *
 467 * This function records information about the index that will be needed for the
 468 * next old index check i.e. 'dbg_check_old_index()'.
 469 *
 470 * This function returns %0 on success and a negative error code on failure.
 471 */
 472int dbg_old_index_check_init(struct ubifs_info *c, struct ubifs_zbranch *zroot)
 473{
 474        struct ubifs_idx_node *idx;
 475        int lnum, offs, len, err = 0;
 476        struct ubifs_debug_info *d = c->dbg;
 477
 478        d->old_zroot = *zroot;
 479        lnum = d->old_zroot.lnum;
 480        offs = d->old_zroot.offs;
 481        len = d->old_zroot.len;
 482
 483        idx = kmalloc(c->max_idx_node_sz, GFP_NOFS);
 484        if (!idx)
 485                return -ENOMEM;
 486
 487        err = ubifs_read_node(c, idx, UBIFS_IDX_NODE, len, lnum, offs);
 488        if (err)
 489                goto out;
 490
 491        d->old_zroot_level = le16_to_cpu(idx->level);
 492        d->old_zroot_sqnum = le64_to_cpu(idx->ch.sqnum);
 493out:
 494        kfree(idx);
 495        return err;
 496}
 497
 498/**
 499 * dbg_check_old_index - check the old copy of the index.
 500 * @c: UBIFS file-system description object
 501 * @zroot: root of the new index
 502 *
 503 * In order to be able to recover from an unclean unmount, a complete copy of
 504 * the index must exist on flash. This is the "old" index. The commit process
 505 * must write the "new" index to flash without overwriting or destroying any
 506 * part of the old index. This function is run at commit end in order to check
 507 * that the old index does indeed exist completely intact.
 508 *
 509 * This function returns %0 on success and a negative error code on failure.
 510 */
 511int dbg_check_old_index(struct ubifs_info *c, struct ubifs_zbranch *zroot)
 512{
 513        int lnum, offs, len, err = 0, uninitialized_var(last_level), child_cnt;
 514        int first = 1, iip;
 515        struct ubifs_debug_info *d = c->dbg;
 516        union ubifs_key uninitialized_var(lower_key), upper_key, l_key, u_key;
 517        unsigned long long uninitialized_var(last_sqnum);
 518        struct ubifs_idx_node *idx;
 519        struct list_head list;
 520        struct idx_node *i;
 521        size_t sz;
 522
 523        if (!(ubifs_chk_flags & UBIFS_CHK_OLD_IDX))
 524                return 0;
 525
 526        INIT_LIST_HEAD(&list);
 527
 528        sz = sizeof(struct idx_node) + ubifs_idx_node_sz(c, c->fanout) -
 529             UBIFS_IDX_NODE_SZ;
 530
 531        /* Start at the old zroot */
 532        lnum = d->old_zroot.lnum;
 533        offs = d->old_zroot.offs;
 534        len = d->old_zroot.len;
 535        iip = 0;
 536
 537        /*
 538         * Traverse the index tree preorder depth-first i.e. do a node and then
 539         * its subtrees from left to right.
 540         */
 541        while (1) {
 542                struct ubifs_branch *br;
 543
 544                /* Get the next index node */
 545                i = kmalloc(sz, GFP_NOFS);
 546                if (!i) {
 547                        err = -ENOMEM;
 548                        goto out_free;
 549                }
 550                i->iip = iip;
 551                /* Keep the index nodes on our path in a linked list */
 552                list_add_tail(&i->list, &list);
 553                /* Read the index node */
 554                idx = &i->idx;
 555                err = ubifs_read_node(c, idx, UBIFS_IDX_NODE, len, lnum, offs);
 556                if (err)
 557                        goto out_free;
 558                /* Validate index node */
 559                child_cnt = le16_to_cpu(idx->child_cnt);
 560                if (child_cnt < 1 || child_cnt > c->fanout) {
 561                        err = 1;
 562                        goto out_dump;
 563                }
 564                if (first) {
 565                        first = 0;
 566                        /* Check root level and sqnum */
 567                        if (le16_to_cpu(idx->level) != d->old_zroot_level) {
 568                                err = 2;
 569                                goto out_dump;
 570                        }
 571                        if (le64_to_cpu(idx->ch.sqnum) != d->old_zroot_sqnum) {
 572                                err = 3;
 573                                goto out_dump;
 574                        }
 575                        /* Set last values as though root had a parent */
 576                        last_level = le16_to_cpu(idx->level) + 1;
 577                        last_sqnum = le64_to_cpu(idx->ch.sqnum) + 1;
 578                        key_read(c, ubifs_idx_key(c, idx), &lower_key);
 579                        highest_ino_key(c, &upper_key, INUM_WATERMARK);
 580                }
 581                key_copy(c, &upper_key, &i->upper_key);
 582                if (le16_to_cpu(idx->level) != last_level - 1) {
 583                        err = 3;
 584                        goto out_dump;
 585                }
 586                /*
 587                 * The index is always written bottom up hence a child's sqnum
 588                 * is always less than the parents.
 589                 */
 590                if (le64_to_cpu(idx->ch.sqnum) >= last_sqnum) {
 591                        err = 4;
 592                        goto out_dump;
 593                }
 594                /* Check key range */
 595                key_read(c, ubifs_idx_key(c, idx), &l_key);
 596                br = ubifs_idx_branch(c, idx, child_cnt - 1);
 597                key_read(c, &br->key, &u_key);
 598                if (keys_cmp(c, &lower_key, &l_key) > 0) {
 599                        err = 5;
 600                        goto out_dump;
 601                }
 602                if (keys_cmp(c, &upper_key, &u_key) < 0) {
 603                        err = 6;
 604                        goto out_dump;
 605                }
 606                if (keys_cmp(c, &upper_key, &u_key) == 0)
 607                        if (!is_hash_key(c, &u_key)) {
 608                                err = 7;
 609                                goto out_dump;
 610                        }
 611                /* Go to next index node */
 612                if (le16_to_cpu(idx->level) == 0) {
 613                        /* At the bottom, so go up until can go right */
 614                        while (1) {
 615                                /* Drop the bottom of the list */
 616                                list_del(&i->list);
 617                                kfree(i);
 618                                /* No more list means we are done */
 619                                if (list_empty(&list))
 620                                        goto out;
 621                                /* Look at the new bottom */
 622                                i = list_entry(list.prev, struct idx_node,
 623                                               list);
 624                                idx = &i->idx;
 625                                /* Can we go right */
 626                                if (iip + 1 < le16_to_cpu(idx->child_cnt)) {
 627                                        iip = iip + 1;
 628                                        break;
 629                                } else
 630                                        /* Nope, so go up again */
 631                                        iip = i->iip;
 632                        }
 633                } else
 634                        /* Go down left */
 635                        iip = 0;
 636                /*
 637                 * We have the parent in 'idx' and now we set up for reading the
 638                 * child pointed to by slot 'iip'.
 639                 */
 640                last_level = le16_to_cpu(idx->level);
 641                last_sqnum = le64_to_cpu(idx->ch.sqnum);
 642                br = ubifs_idx_branch(c, idx, iip);
 643                lnum = le32_to_cpu(br->lnum);
 644                offs = le32_to_cpu(br->offs);
 645                len = le32_to_cpu(br->len);
 646                key_read(c, &br->key, &lower_key);
 647                if (iip + 1 < le16_to_cpu(idx->child_cnt)) {
 648                        br = ubifs_idx_branch(c, idx, iip + 1);
 649                        key_read(c, &br->key, &upper_key);
 650                } else
 651                        key_copy(c, &i->upper_key, &upper_key);
 652        }
 653out:
 654        err = dbg_old_index_check_init(c, zroot);
 655        if (err)
 656                goto out_free;
 657
 658        return 0;
 659
 660out_dump:
 661        dbg_err("dumping index node (iip=%d)", i->iip);
 662        dbg_dump_node(c, idx);
 663        list_del(&i->list);
 664        kfree(i);
 665        if (!list_empty(&list)) {
 666                i = list_entry(list.prev, struct idx_node, list);
 667                dbg_err("dumping parent index node");
 668                dbg_dump_node(c, &i->idx);
 669        }
 670out_free:
 671        while (!list_empty(&list)) {
 672                i = list_entry(list.next, struct idx_node, list);
 673                list_del(&i->list);
 674                kfree(i);
 675        }
 676        ubifs_err("failed, error %d", err);
 677        if (err > 0)
 678                err = -EINVAL;
 679        return err;
 680}
 681
 682#endif /* CONFIG_UBIFS_FS_DEBUG */
 683