linux/fs/ubifs/commit.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * This file is part of UBIFS.
   4 *
   5 * Copyright (C) 2006-2008 Nokia Corporation.
   6 *
   7 * Authors: Adrian Hunter
   8 *          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)
   9 */
  10
  11/*
  12 * This file implements functions that manage the running of the commit process.
  13 * Each affected module has its own functions to accomplish their part in the
  14 * commit and those functions are called here.
  15 *
  16 * The commit is the process whereby all updates to the index and LEB properties
  17 * are written out together and the journal becomes empty. This keeps the
  18 * file system consistent - at all times the state can be recreated by reading
  19 * the index and LEB properties and then replaying the journal.
  20 *
  21 * The commit is split into two parts named "commit start" and "commit end".
  22 * During commit start, the commit process has exclusive access to the journal
  23 * by holding the commit semaphore down for writing. As few I/O operations as
  24 * possible are performed during commit start, instead the nodes that are to be
  25 * written are merely identified. During commit end, the commit semaphore is no
  26 * longer held and the journal is again in operation, allowing users to continue
  27 * to use the file system while the bulk of the commit I/O is performed. The
  28 * purpose of this two-step approach is to prevent the commit from causing any
  29 * latency blips. Note that in any case, the commit does not prevent lookups
  30 * (as permitted by the TNC mutex), or access to VFS data structures e.g. page
  31 * cache.
  32 */
  33
  34#include <linux/freezer.h>
  35#include <linux/kthread.h>
  36#include <linux/slab.h>
  37#include "ubifs.h"
  38
  39/*
  40 * nothing_to_commit - check if there is nothing to commit.
  41 * @c: UBIFS file-system description object
  42 *
  43 * This is a helper function which checks if there is anything to commit. It is
  44 * used as an optimization to avoid starting the commit if it is not really
  45 * necessary. Indeed, the commit operation always assumes flash I/O (e.g.,
  46 * writing the commit start node to the log), and it is better to avoid doing
  47 * this unnecessarily. E.g., 'ubifs_sync_fs()' runs the commit, but if there is
  48 * nothing to commit, it is more optimal to avoid any flash I/O.
  49 *
  50 * This function has to be called with @c->commit_sem locked for writing -
  51 * this function does not take LPT/TNC locks because the @c->commit_sem
  52 * guarantees that we have exclusive access to the TNC and LPT data structures.
  53 *
  54 * This function returns %1 if there is nothing to commit and %0 otherwise.
  55 */
  56static int nothing_to_commit(struct ubifs_info *c)
  57{
  58        /*
  59         * During mounting or remounting from R/O mode to R/W mode we may
  60         * commit for various recovery-related reasons.
  61         */
  62        if (c->mounting || c->remounting_rw)
  63                return 0;
  64
  65        /*
  66         * If the root TNC node is dirty, we definitely have something to
  67         * commit.
  68         */
  69        if (c->zroot.znode && ubifs_zn_dirty(c->zroot.znode))
  70                return 0;
  71
  72        /*
  73         * Even though the TNC is clean, the LPT tree may have dirty nodes. For
  74         * example, this may happen if the budgeting subsystem invoked GC to
  75         * make some free space, and the GC found an LEB with only dirty and
  76         * free space. In this case GC would just change the lprops of this
  77         * LEB (by turning all space into free space) and unmap it.
  78         */
  79        if (c->nroot && test_bit(DIRTY_CNODE, &c->nroot->flags))
  80                return 0;
  81
  82        ubifs_assert(c, atomic_long_read(&c->dirty_zn_cnt) == 0);
  83        ubifs_assert(c, c->dirty_pn_cnt == 0);
  84        ubifs_assert(c, c->dirty_nn_cnt == 0);
  85
  86        return 1;
  87}
  88
  89/**
  90 * do_commit - commit the journal.
  91 * @c: UBIFS file-system description object
  92 *
  93 * This function implements UBIFS commit. It has to be called with commit lock
  94 * locked. Returns zero in case of success and a negative error code in case of
  95 * failure.
  96 */
  97static int do_commit(struct ubifs_info *c)
  98{
  99        int err, new_ltail_lnum, old_ltail_lnum, i;
 100        struct ubifs_zbranch zroot;
 101        struct ubifs_lp_stats lst;
 102
 103        dbg_cmt("start");
 104        ubifs_assert(c, !c->ro_media && !c->ro_mount);
 105
 106        if (c->ro_error) {
 107                err = -EROFS;
 108                goto out_up;
 109        }
 110
 111        if (nothing_to_commit(c)) {
 112                up_write(&c->commit_sem);
 113                err = 0;
 114                goto out_cancel;
 115        }
 116
 117        /* Sync all write buffers (necessary for recovery) */
 118        for (i = 0; i < c->jhead_cnt; i++) {
 119                err = ubifs_wbuf_sync(&c->jheads[i].wbuf);
 120                if (err)
 121                        goto out_up;
 122        }
 123
 124        c->cmt_no += 1;
 125        err = ubifs_gc_start_commit(c);
 126        if (err)
 127                goto out_up;
 128        err = dbg_check_lprops(c);
 129        if (err)
 130                goto out_up;
 131        err = ubifs_log_start_commit(c, &new_ltail_lnum);
 132        if (err)
 133                goto out_up;
 134        err = ubifs_tnc_start_commit(c, &zroot);
 135        if (err)
 136                goto out_up;
 137        err = ubifs_lpt_start_commit(c);
 138        if (err)
 139                goto out_up;
 140        err = ubifs_orphan_start_commit(c);
 141        if (err)
 142                goto out_up;
 143
 144        ubifs_get_lp_stats(c, &lst);
 145
 146        up_write(&c->commit_sem);
 147
 148        err = ubifs_tnc_end_commit(c);
 149        if (err)
 150                goto out;
 151        err = ubifs_lpt_end_commit(c);
 152        if (err)
 153                goto out;
 154        err = ubifs_orphan_end_commit(c);
 155        if (err)
 156                goto out;
 157        err = dbg_check_old_index(c, &zroot);
 158        if (err)
 159                goto out;
 160
 161        c->mst_node->cmt_no      = cpu_to_le64(c->cmt_no);
 162        c->mst_node->log_lnum    = cpu_to_le32(new_ltail_lnum);
 163        c->mst_node->root_lnum   = cpu_to_le32(zroot.lnum);
 164        c->mst_node->root_offs   = cpu_to_le32(zroot.offs);
 165        c->mst_node->root_len    = cpu_to_le32(zroot.len);
 166        c->mst_node->ihead_lnum  = cpu_to_le32(c->ihead_lnum);
 167        c->mst_node->ihead_offs  = cpu_to_le32(c->ihead_offs);
 168        c->mst_node->index_size  = cpu_to_le64(c->bi.old_idx_sz);
 169        c->mst_node->lpt_lnum    = cpu_to_le32(c->lpt_lnum);
 170        c->mst_node->lpt_offs    = cpu_to_le32(c->lpt_offs);
 171        c->mst_node->nhead_lnum  = cpu_to_le32(c->nhead_lnum);
 172        c->mst_node->nhead_offs  = cpu_to_le32(c->nhead_offs);
 173        c->mst_node->ltab_lnum   = cpu_to_le32(c->ltab_lnum);
 174        c->mst_node->ltab_offs   = cpu_to_le32(c->ltab_offs);
 175        c->mst_node->lsave_lnum  = cpu_to_le32(c->lsave_lnum);
 176        c->mst_node->lsave_offs  = cpu_to_le32(c->lsave_offs);
 177        c->mst_node->lscan_lnum  = cpu_to_le32(c->lscan_lnum);
 178        c->mst_node->empty_lebs  = cpu_to_le32(lst.empty_lebs);
 179        c->mst_node->idx_lebs    = cpu_to_le32(lst.idx_lebs);
 180        c->mst_node->total_free  = cpu_to_le64(lst.total_free);
 181        c->mst_node->total_dirty = cpu_to_le64(lst.total_dirty);
 182        c->mst_node->total_used  = cpu_to_le64(lst.total_used);
 183        c->mst_node->total_dead  = cpu_to_le64(lst.total_dead);
 184        c->mst_node->total_dark  = cpu_to_le64(lst.total_dark);
 185        if (c->no_orphs)
 186                c->mst_node->flags |= cpu_to_le32(UBIFS_MST_NO_ORPHS);
 187        else
 188                c->mst_node->flags &= ~cpu_to_le32(UBIFS_MST_NO_ORPHS);
 189
 190        old_ltail_lnum = c->ltail_lnum;
 191        err = ubifs_log_end_commit(c, new_ltail_lnum);
 192        if (err)
 193                goto out;
 194
 195        err = ubifs_log_post_commit(c, old_ltail_lnum);
 196        if (err)
 197                goto out;
 198        err = ubifs_gc_end_commit(c);
 199        if (err)
 200                goto out;
 201        err = ubifs_lpt_post_commit(c);
 202        if (err)
 203                goto out;
 204
 205out_cancel:
 206        spin_lock(&c->cs_lock);
 207        c->cmt_state = COMMIT_RESTING;
 208        wake_up(&c->cmt_wq);
 209        dbg_cmt("commit end");
 210        spin_unlock(&c->cs_lock);
 211        return 0;
 212
 213out_up:
 214        up_write(&c->commit_sem);
 215out:
 216        ubifs_err(c, "commit failed, error %d", err);
 217        spin_lock(&c->cs_lock);
 218        c->cmt_state = COMMIT_BROKEN;
 219        wake_up(&c->cmt_wq);
 220        spin_unlock(&c->cs_lock);
 221        ubifs_ro_mode(c, err);
 222        return err;
 223}
 224
 225/**
 226 * run_bg_commit - run background commit if it is needed.
 227 * @c: UBIFS file-system description object
 228 *
 229 * This function runs background commit if it is needed. Returns zero in case
 230 * of success and a negative error code in case of failure.
 231 */
 232static int run_bg_commit(struct ubifs_info *c)
 233{
 234        spin_lock(&c->cs_lock);
 235        /*
 236         * Run background commit only if background commit was requested or if
 237         * commit is required.
 238         */
 239        if (c->cmt_state != COMMIT_BACKGROUND &&
 240            c->cmt_state != COMMIT_REQUIRED)
 241                goto out;
 242        spin_unlock(&c->cs_lock);
 243
 244        down_write(&c->commit_sem);
 245        spin_lock(&c->cs_lock);
 246        if (c->cmt_state == COMMIT_REQUIRED)
 247                c->cmt_state = COMMIT_RUNNING_REQUIRED;
 248        else if (c->cmt_state == COMMIT_BACKGROUND)
 249                c->cmt_state = COMMIT_RUNNING_BACKGROUND;
 250        else
 251                goto out_cmt_unlock;
 252        spin_unlock(&c->cs_lock);
 253
 254        return do_commit(c);
 255
 256out_cmt_unlock:
 257        up_write(&c->commit_sem);
 258out:
 259        spin_unlock(&c->cs_lock);
 260        return 0;
 261}
 262
 263/**
 264 * ubifs_bg_thread - UBIFS background thread function.
 265 * @info: points to the file-system description object
 266 *
 267 * This function implements various file-system background activities:
 268 * o when a write-buffer timer expires it synchronizes the appropriate
 269 *   write-buffer;
 270 * o when the journal is about to be full, it starts in-advance commit.
 271 *
 272 * Note, other stuff like background garbage collection may be added here in
 273 * future.
 274 */
 275int ubifs_bg_thread(void *info)
 276{
 277        int err;
 278        struct ubifs_info *c = info;
 279
 280        ubifs_msg(c, "background thread \"%s\" started, PID %d",
 281                  c->bgt_name, current->pid);
 282        set_freezable();
 283
 284        while (1) {
 285                if (kthread_should_stop())
 286                        break;
 287
 288                if (try_to_freeze())
 289                        continue;
 290
 291                set_current_state(TASK_INTERRUPTIBLE);
 292                /* Check if there is something to do */
 293                if (!c->need_bgt) {
 294                        /*
 295                         * Nothing prevents us from going sleep now and
 296                         * be never woken up and block the task which
 297                         * could wait in 'kthread_stop()' forever.
 298                         */
 299                        if (kthread_should_stop())
 300                                break;
 301                        schedule();
 302                        continue;
 303                } else
 304                        __set_current_state(TASK_RUNNING);
 305
 306                c->need_bgt = 0;
 307                err = ubifs_bg_wbufs_sync(c);
 308                if (err)
 309                        ubifs_ro_mode(c, err);
 310
 311                run_bg_commit(c);
 312                cond_resched();
 313        }
 314
 315        ubifs_msg(c, "background thread \"%s\" stops", c->bgt_name);
 316        return 0;
 317}
 318
 319/**
 320 * ubifs_commit_required - set commit state to "required".
 321 * @c: UBIFS file-system description object
 322 *
 323 * This function is called if a commit is required but cannot be done from the
 324 * calling function, so it is just flagged instead.
 325 */
 326void ubifs_commit_required(struct ubifs_info *c)
 327{
 328        spin_lock(&c->cs_lock);
 329        switch (c->cmt_state) {
 330        case COMMIT_RESTING:
 331        case COMMIT_BACKGROUND:
 332                dbg_cmt("old: %s, new: %s", dbg_cstate(c->cmt_state),
 333                        dbg_cstate(COMMIT_REQUIRED));
 334                c->cmt_state = COMMIT_REQUIRED;
 335                break;
 336        case COMMIT_RUNNING_BACKGROUND:
 337                dbg_cmt("old: %s, new: %s", dbg_cstate(c->cmt_state),
 338                        dbg_cstate(COMMIT_RUNNING_REQUIRED));
 339                c->cmt_state = COMMIT_RUNNING_REQUIRED;
 340                break;
 341        case COMMIT_REQUIRED:
 342        case COMMIT_RUNNING_REQUIRED:
 343        case COMMIT_BROKEN:
 344                break;
 345        }
 346        spin_unlock(&c->cs_lock);
 347}
 348
 349/**
 350 * ubifs_request_bg_commit - notify the background thread to do a commit.
 351 * @c: UBIFS file-system description object
 352 *
 353 * This function is called if the journal is full enough to make a commit
 354 * worthwhile, so background thread is kicked to start it.
 355 */
 356void ubifs_request_bg_commit(struct ubifs_info *c)
 357{
 358        spin_lock(&c->cs_lock);
 359        if (c->cmt_state == COMMIT_RESTING) {
 360                dbg_cmt("old: %s, new: %s", dbg_cstate(c->cmt_state),
 361                        dbg_cstate(COMMIT_BACKGROUND));
 362                c->cmt_state = COMMIT_BACKGROUND;
 363                spin_unlock(&c->cs_lock);
 364                ubifs_wake_up_bgt(c);
 365        } else
 366                spin_unlock(&c->cs_lock);
 367}
 368
 369/**
 370 * wait_for_commit - wait for commit.
 371 * @c: UBIFS file-system description object
 372 *
 373 * This function sleeps until the commit operation is no longer running.
 374 */
 375static int wait_for_commit(struct ubifs_info *c)
 376{
 377        dbg_cmt("pid %d goes sleep", current->pid);
 378
 379        /*
 380         * The following sleeps if the condition is false, and will be woken
 381         * when the commit ends. It is possible, although very unlikely, that we
 382         * will wake up and see the subsequent commit running, rather than the
 383         * one we were waiting for, and go back to sleep.  However, we will be
 384         * woken again, so there is no danger of sleeping forever.
 385         */
 386        wait_event(c->cmt_wq, c->cmt_state != COMMIT_RUNNING_BACKGROUND &&
 387                              c->cmt_state != COMMIT_RUNNING_REQUIRED);
 388        dbg_cmt("commit finished, pid %d woke up", current->pid);
 389        return 0;
 390}
 391
 392/**
 393 * ubifs_run_commit - run or wait for commit.
 394 * @c: UBIFS file-system description object
 395 *
 396 * This function runs commit and returns zero in case of success and a negative
 397 * error code in case of failure.
 398 */
 399int ubifs_run_commit(struct ubifs_info *c)
 400{
 401        int err = 0;
 402
 403        spin_lock(&c->cs_lock);
 404        if (c->cmt_state == COMMIT_BROKEN) {
 405                err = -EROFS;
 406                goto out;
 407        }
 408
 409        if (c->cmt_state == COMMIT_RUNNING_BACKGROUND)
 410                /*
 411                 * We set the commit state to 'running required' to indicate
 412                 * that we want it to complete as quickly as possible.
 413                 */
 414                c->cmt_state = COMMIT_RUNNING_REQUIRED;
 415
 416        if (c->cmt_state == COMMIT_RUNNING_REQUIRED) {
 417                spin_unlock(&c->cs_lock);
 418                return wait_for_commit(c);
 419        }
 420        spin_unlock(&c->cs_lock);
 421
 422        /* Ok, the commit is indeed needed */
 423
 424        down_write(&c->commit_sem);
 425        spin_lock(&c->cs_lock);
 426        /*
 427         * Since we unlocked 'c->cs_lock', the state may have changed, so
 428         * re-check it.
 429         */
 430        if (c->cmt_state == COMMIT_BROKEN) {
 431                err = -EROFS;
 432                goto out_cmt_unlock;
 433        }
 434
 435        if (c->cmt_state == COMMIT_RUNNING_BACKGROUND)
 436                c->cmt_state = COMMIT_RUNNING_REQUIRED;
 437
 438        if (c->cmt_state == COMMIT_RUNNING_REQUIRED) {
 439                up_write(&c->commit_sem);
 440                spin_unlock(&c->cs_lock);
 441                return wait_for_commit(c);
 442        }
 443        c->cmt_state = COMMIT_RUNNING_REQUIRED;
 444        spin_unlock(&c->cs_lock);
 445
 446        err = do_commit(c);
 447        return err;
 448
 449out_cmt_unlock:
 450        up_write(&c->commit_sem);
 451out:
 452        spin_unlock(&c->cs_lock);
 453        return err;
 454}
 455
 456/**
 457 * ubifs_gc_should_commit - determine if it is time for GC to run commit.
 458 * @c: UBIFS file-system description object
 459 *
 460 * This function is called by garbage collection to determine if commit should
 461 * be run. If commit state is @COMMIT_BACKGROUND, which means that the journal
 462 * is full enough to start commit, this function returns true. It is not
 463 * absolutely necessary to commit yet, but it feels like this should be better
 464 * then to keep doing GC. This function returns %1 if GC has to initiate commit
 465 * and %0 if not.
 466 */
 467int ubifs_gc_should_commit(struct ubifs_info *c)
 468{
 469        int ret = 0;
 470
 471        spin_lock(&c->cs_lock);
 472        if (c->cmt_state == COMMIT_BACKGROUND) {
 473                dbg_cmt("commit required now");
 474                c->cmt_state = COMMIT_REQUIRED;
 475        } else
 476                dbg_cmt("commit not requested");
 477        if (c->cmt_state == COMMIT_REQUIRED)
 478                ret = 1;
 479        spin_unlock(&c->cs_lock);
 480        return ret;
 481}
 482
 483/*
 484 * Everything below is related to debugging.
 485 */
 486
 487/**
 488 * struct idx_node - hold index nodes during index tree traversal.
 489 * @list: list
 490 * @iip: index in parent (slot number of this indexing node in the parent
 491 *       indexing node)
 492 * @upper_key: all keys in this indexing node have to be less or equivalent to
 493 *             this key
 494 * @idx: index node (8-byte aligned because all node structures must be 8-byte
 495 *       aligned)
 496 */
 497struct idx_node {
 498        struct list_head list;
 499        int iip;
 500        union ubifs_key upper_key;
 501        struct ubifs_idx_node idx __aligned(8);
 502};
 503
 504/**
 505 * dbg_old_index_check_init - get information for the next old index check.
 506 * @c: UBIFS file-system description object
 507 * @zroot: root of the index
 508 *
 509 * This function records information about the index that will be needed for the
 510 * next old index check i.e. 'dbg_check_old_index()'.
 511 *
 512 * This function returns %0 on success and a negative error code on failure.
 513 */
 514int dbg_old_index_check_init(struct ubifs_info *c, struct ubifs_zbranch *zroot)
 515{
 516        struct ubifs_idx_node *idx;
 517        int lnum, offs, len, err = 0;
 518        struct ubifs_debug_info *d = c->dbg;
 519
 520        d->old_zroot = *zroot;
 521        lnum = d->old_zroot.lnum;
 522        offs = d->old_zroot.offs;
 523        len = d->old_zroot.len;
 524
 525        idx = kmalloc(c->max_idx_node_sz, GFP_NOFS);
 526        if (!idx)
 527                return -ENOMEM;
 528
 529        err = ubifs_read_node(c, idx, UBIFS_IDX_NODE, len, lnum, offs);
 530        if (err)
 531                goto out;
 532
 533        d->old_zroot_level = le16_to_cpu(idx->level);
 534        d->old_zroot_sqnum = le64_to_cpu(idx->ch.sqnum);
 535out:
 536        kfree(idx);
 537        return err;
 538}
 539
 540/**
 541 * dbg_check_old_index - check the old copy of the index.
 542 * @c: UBIFS file-system description object
 543 * @zroot: root of the new index
 544 *
 545 * In order to be able to recover from an unclean unmount, a complete copy of
 546 * the index must exist on flash. This is the "old" index. The commit process
 547 * must write the "new" index to flash without overwriting or destroying any
 548 * part of the old index. This function is run at commit end in order to check
 549 * that the old index does indeed exist completely intact.
 550 *
 551 * This function returns %0 on success and a negative error code on failure.
 552 */
 553int dbg_check_old_index(struct ubifs_info *c, struct ubifs_zbranch *zroot)
 554{
 555        int lnum, offs, len, err = 0, last_level, child_cnt;
 556        int first = 1, iip;
 557        struct ubifs_debug_info *d = c->dbg;
 558        union ubifs_key lower_key, upper_key, l_key, u_key;
 559        unsigned long long last_sqnum;
 560        struct ubifs_idx_node *idx;
 561        struct list_head list;
 562        struct idx_node *i;
 563        size_t sz;
 564
 565        if (!dbg_is_chk_index(c))
 566                return 0;
 567
 568        INIT_LIST_HEAD(&list);
 569
 570        sz = sizeof(struct idx_node) + ubifs_idx_node_sz(c, c->fanout) -
 571             UBIFS_IDX_NODE_SZ;
 572
 573        /* Start at the old zroot */
 574        lnum = d->old_zroot.lnum;
 575        offs = d->old_zroot.offs;
 576        len = d->old_zroot.len;
 577        iip = 0;
 578
 579        /*
 580         * Traverse the index tree preorder depth-first i.e. do a node and then
 581         * its subtrees from left to right.
 582         */
 583        while (1) {
 584                struct ubifs_branch *br;
 585
 586                /* Get the next index node */
 587                i = kmalloc(sz, GFP_NOFS);
 588                if (!i) {
 589                        err = -ENOMEM;
 590                        goto out_free;
 591                }
 592                i->iip = iip;
 593                /* Keep the index nodes on our path in a linked list */
 594                list_add_tail(&i->list, &list);
 595                /* Read the index node */
 596                idx = &i->idx;
 597                err = ubifs_read_node(c, idx, UBIFS_IDX_NODE, len, lnum, offs);
 598                if (err)
 599                        goto out_free;
 600                /* Validate index node */
 601                child_cnt = le16_to_cpu(idx->child_cnt);
 602                if (child_cnt < 1 || child_cnt > c->fanout) {
 603                        err = 1;
 604                        goto out_dump;
 605                }
 606                if (first) {
 607                        first = 0;
 608                        /* Check root level and sqnum */
 609                        if (le16_to_cpu(idx->level) != d->old_zroot_level) {
 610                                err = 2;
 611                                goto out_dump;
 612                        }
 613                        if (le64_to_cpu(idx->ch.sqnum) != d->old_zroot_sqnum) {
 614                                err = 3;
 615                                goto out_dump;
 616                        }
 617                        /* Set last values as though root had a parent */
 618                        last_level = le16_to_cpu(idx->level) + 1;
 619                        last_sqnum = le64_to_cpu(idx->ch.sqnum) + 1;
 620                        key_read(c, ubifs_idx_key(c, idx), &lower_key);
 621                        highest_ino_key(c, &upper_key, INUM_WATERMARK);
 622                }
 623                key_copy(c, &upper_key, &i->upper_key);
 624                if (le16_to_cpu(idx->level) != last_level - 1) {
 625                        err = 3;
 626                        goto out_dump;
 627                }
 628                /*
 629                 * The index is always written bottom up hence a child's sqnum
 630                 * is always less than the parents.
 631                 */
 632                if (le64_to_cpu(idx->ch.sqnum) >= last_sqnum) {
 633                        err = 4;
 634                        goto out_dump;
 635                }
 636                /* Check key range */
 637                key_read(c, ubifs_idx_key(c, idx), &l_key);
 638                br = ubifs_idx_branch(c, idx, child_cnt - 1);
 639                key_read(c, &br->key, &u_key);
 640                if (keys_cmp(c, &lower_key, &l_key) > 0) {
 641                        err = 5;
 642                        goto out_dump;
 643                }
 644                if (keys_cmp(c, &upper_key, &u_key) < 0) {
 645                        err = 6;
 646                        goto out_dump;
 647                }
 648                if (keys_cmp(c, &upper_key, &u_key) == 0)
 649                        if (!is_hash_key(c, &u_key)) {
 650                                err = 7;
 651                                goto out_dump;
 652                        }
 653                /* Go to next index node */
 654                if (le16_to_cpu(idx->level) == 0) {
 655                        /* At the bottom, so go up until can go right */
 656                        while (1) {
 657                                /* Drop the bottom of the list */
 658                                list_del(&i->list);
 659                                kfree(i);
 660                                /* No more list means we are done */
 661                                if (list_empty(&list))
 662                                        goto out;
 663                                /* Look at the new bottom */
 664                                i = list_entry(list.prev, struct idx_node,
 665                                               list);
 666                                idx = &i->idx;
 667                                /* Can we go right */
 668                                if (iip + 1 < le16_to_cpu(idx->child_cnt)) {
 669                                        iip = iip + 1;
 670                                        break;
 671                                } else
 672                                        /* Nope, so go up again */
 673                                        iip = i->iip;
 674                        }
 675                } else
 676                        /* Go down left */
 677                        iip = 0;
 678                /*
 679                 * We have the parent in 'idx' and now we set up for reading the
 680                 * child pointed to by slot 'iip'.
 681                 */
 682                last_level = le16_to_cpu(idx->level);
 683                last_sqnum = le64_to_cpu(idx->ch.sqnum);
 684                br = ubifs_idx_branch(c, idx, iip);
 685                lnum = le32_to_cpu(br->lnum);
 686                offs = le32_to_cpu(br->offs);
 687                len = le32_to_cpu(br->len);
 688                key_read(c, &br->key, &lower_key);
 689                if (iip + 1 < le16_to_cpu(idx->child_cnt)) {
 690                        br = ubifs_idx_branch(c, idx, iip + 1);
 691                        key_read(c, &br->key, &upper_key);
 692                } else
 693                        key_copy(c, &i->upper_key, &upper_key);
 694        }
 695out:
 696        err = dbg_old_index_check_init(c, zroot);
 697        if (err)
 698                goto out_free;
 699
 700        return 0;
 701
 702out_dump:
 703        ubifs_err(c, "dumping index node (iip=%d)", i->iip);
 704        ubifs_dump_node(c, idx, ubifs_idx_node_sz(c, c->fanout));
 705        list_del(&i->list);
 706        kfree(i);
 707        if (!list_empty(&list)) {
 708                i = list_entry(list.prev, struct idx_node, list);
 709                ubifs_err(c, "dumping parent index node");
 710                ubifs_dump_node(c, &i->idx, ubifs_idx_node_sz(c, c->fanout));
 711        }
 712out_free:
 713        while (!list_empty(&list)) {
 714                i = list_entry(list.next, struct idx_node, list);
 715                list_del(&i->list);
 716                kfree(i);
 717        }
 718        ubifs_err(c, "failed, error %d", err);
 719        if (err > 0)
 720                err = -EINVAL;
 721        return err;
 722}
 723