root/fs/ubifs/commit.c

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DEFINITIONS

This source file includes following definitions.
  1. nothing_to_commit
  2. do_commit
  3. run_bg_commit
  4. ubifs_bg_thread
  5. ubifs_commit_required
  6. ubifs_request_bg_commit
  7. wait_for_commit
  8. ubifs_run_commit
  9. ubifs_gc_should_commit
  10. dbg_old_index_check_init
  11. dbg_check_old_index

   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 (Битюцкий Артём)
   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  */
  56 static 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  */
  97 static 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 
 205 out_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 
 213 out_up:
 214         up_write(&c->commit_sem);
 215 out:
 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  */
 232 static 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 
 256 out_cmt_unlock:
 257         up_write(&c->commit_sem);
 258 out:
 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  */
 275 int 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  */
 326 void 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  */
 356 void 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  */
 375 static 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  */
 399 int 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 
 449 out_cmt_unlock:
 450         up_write(&c->commit_sem);
 451 out:
 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  */
 467 int 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  */
 497 struct 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  */
 514 int 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);
 535 out:
 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  */
 553 int dbg_check_old_index(struct ubifs_info *c, struct ubifs_zbranch *zroot)
 554 {
 555         int lnum, offs, len, err = 0, uninitialized_var(last_level), child_cnt;
 556         int first = 1, iip;
 557         struct ubifs_debug_info *d = c->dbg;
 558         union ubifs_key uninitialized_var(lower_key), upper_key, l_key, u_key;
 559         unsigned long long uninitialized_var(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         }
 695 out:
 696         err = dbg_old_index_check_init(c, zroot);
 697         if (err)
 698                 goto out_free;
 699 
 700         return 0;
 701 
 702 out_dump:
 703         ubifs_err(c, "dumping index node (iip=%d)", i->iip);
 704         ubifs_dump_node(c, idx);
 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);
 711         }
 712 out_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 }

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