uboot/fs/ubifs/replay.c
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   1/*
   2 * This file is part of UBIFS.
   3 *
   4 * Copyright (C) 2006-2008 Nokia Corporation.
   5 *
   6 * SPDX-License-Identifier:     GPL-2.0+
   7 *
   8 * Authors: Adrian Hunter
   9 *          Artem Bityutskiy (Битюцкий Артём)
  10 */
  11
  12/*
  13 * This file contains journal replay code. It runs when the file-system is being
  14 * mounted and requires no locking.
  15 *
  16 * The larger is the journal, the longer it takes to scan it, so the longer it
  17 * takes to mount UBIFS. This is why the journal has limited size which may be
  18 * changed depending on the system requirements. But a larger journal gives
  19 * faster I/O speed because it writes the index less frequently. So this is a
  20 * trade-off. Also, the journal is indexed by the in-memory index (TNC), so the
  21 * larger is the journal, the more memory its index may consume.
  22 */
  23
  24#ifdef __UBOOT__
  25#include <linux/compat.h>
  26#include <linux/err.h>
  27#endif
  28#include "ubifs.h"
  29#include <linux/bug.h>
  30#include <linux/list_sort.h>
  31
  32/**
  33 * struct replay_entry - replay list entry.
  34 * @lnum: logical eraseblock number of the node
  35 * @offs: node offset
  36 * @len: node length
  37 * @deletion: non-zero if this entry corresponds to a node deletion
  38 * @sqnum: node sequence number
  39 * @list: links the replay list
  40 * @key: node key
  41 * @nm: directory entry name
  42 * @old_size: truncation old size
  43 * @new_size: truncation new size
  44 *
  45 * The replay process first scans all buds and builds the replay list, then
  46 * sorts the replay list in nodes sequence number order, and then inserts all
  47 * the replay entries to the TNC.
  48 */
  49struct replay_entry {
  50        int lnum;
  51        int offs;
  52        int len;
  53        unsigned int deletion:1;
  54        unsigned long long sqnum;
  55        struct list_head list;
  56        union ubifs_key key;
  57        union {
  58                struct qstr nm;
  59                struct {
  60                        loff_t old_size;
  61                        loff_t new_size;
  62                };
  63        };
  64};
  65
  66/**
  67 * struct bud_entry - entry in the list of buds to replay.
  68 * @list: next bud in the list
  69 * @bud: bud description object
  70 * @sqnum: reference node sequence number
  71 * @free: free bytes in the bud
  72 * @dirty: dirty bytes in the bud
  73 */
  74struct bud_entry {
  75        struct list_head list;
  76        struct ubifs_bud *bud;
  77        unsigned long long sqnum;
  78        int free;
  79        int dirty;
  80};
  81
  82/**
  83 * set_bud_lprops - set free and dirty space used by a bud.
  84 * @c: UBIFS file-system description object
  85 * @b: bud entry which describes the bud
  86 *
  87 * This function makes sure the LEB properties of bud @b are set correctly
  88 * after the replay. Returns zero in case of success and a negative error code
  89 * in case of failure.
  90 */
  91static int set_bud_lprops(struct ubifs_info *c, struct bud_entry *b)
  92{
  93        const struct ubifs_lprops *lp;
  94        int err = 0, dirty;
  95
  96        ubifs_get_lprops(c);
  97
  98        lp = ubifs_lpt_lookup_dirty(c, b->bud->lnum);
  99        if (IS_ERR(lp)) {
 100                err = PTR_ERR(lp);
 101                goto out;
 102        }
 103
 104        dirty = lp->dirty;
 105        if (b->bud->start == 0 && (lp->free != c->leb_size || lp->dirty != 0)) {
 106                /*
 107                 * The LEB was added to the journal with a starting offset of
 108                 * zero which means the LEB must have been empty. The LEB
 109                 * property values should be @lp->free == @c->leb_size and
 110                 * @lp->dirty == 0, but that is not the case. The reason is that
 111                 * the LEB had been garbage collected before it became the bud,
 112                 * and there was not commit inbetween. The garbage collector
 113                 * resets the free and dirty space without recording it
 114                 * anywhere except lprops, so if there was no commit then
 115                 * lprops does not have that information.
 116                 *
 117                 * We do not need to adjust free space because the scan has told
 118                 * us the exact value which is recorded in the replay entry as
 119                 * @b->free.
 120                 *
 121                 * However we do need to subtract from the dirty space the
 122                 * amount of space that the garbage collector reclaimed, which
 123                 * is the whole LEB minus the amount of space that was free.
 124                 */
 125                dbg_mnt("bud LEB %d was GC'd (%d free, %d dirty)", b->bud->lnum,
 126                        lp->free, lp->dirty);
 127                dbg_gc("bud LEB %d was GC'd (%d free, %d dirty)", b->bud->lnum,
 128                        lp->free, lp->dirty);
 129                dirty -= c->leb_size - lp->free;
 130                /*
 131                 * If the replay order was perfect the dirty space would now be
 132                 * zero. The order is not perfect because the journal heads
 133                 * race with each other. This is not a problem but is does mean
 134                 * that the dirty space may temporarily exceed c->leb_size
 135                 * during the replay.
 136                 */
 137                if (dirty != 0)
 138                        dbg_mnt("LEB %d lp: %d free %d dirty replay: %d free %d dirty",
 139                                b->bud->lnum, lp->free, lp->dirty, b->free,
 140                                b->dirty);
 141        }
 142        lp = ubifs_change_lp(c, lp, b->free, dirty + b->dirty,
 143                             lp->flags | LPROPS_TAKEN, 0);
 144        if (IS_ERR(lp)) {
 145                err = PTR_ERR(lp);
 146                goto out;
 147        }
 148
 149        /* Make sure the journal head points to the latest bud */
 150        err = ubifs_wbuf_seek_nolock(&c->jheads[b->bud->jhead].wbuf,
 151                                     b->bud->lnum, c->leb_size - b->free);
 152
 153out:
 154        ubifs_release_lprops(c);
 155        return err;
 156}
 157
 158/**
 159 * set_buds_lprops - set free and dirty space for all replayed buds.
 160 * @c: UBIFS file-system description object
 161 *
 162 * This function sets LEB properties for all replayed buds. Returns zero in
 163 * case of success and a negative error code in case of failure.
 164 */
 165static int set_buds_lprops(struct ubifs_info *c)
 166{
 167        struct bud_entry *b;
 168        int err;
 169
 170        list_for_each_entry(b, &c->replay_buds, list) {
 171                err = set_bud_lprops(c, b);
 172                if (err)
 173                        return err;
 174        }
 175
 176        return 0;
 177}
 178
 179/**
 180 * trun_remove_range - apply a replay entry for a truncation to the TNC.
 181 * @c: UBIFS file-system description object
 182 * @r: replay entry of truncation
 183 */
 184static int trun_remove_range(struct ubifs_info *c, struct replay_entry *r)
 185{
 186        unsigned min_blk, max_blk;
 187        union ubifs_key min_key, max_key;
 188        ino_t ino;
 189
 190        min_blk = r->new_size / UBIFS_BLOCK_SIZE;
 191        if (r->new_size & (UBIFS_BLOCK_SIZE - 1))
 192                min_blk += 1;
 193
 194        max_blk = r->old_size / UBIFS_BLOCK_SIZE;
 195        if ((r->old_size & (UBIFS_BLOCK_SIZE - 1)) == 0)
 196                max_blk -= 1;
 197
 198        ino = key_inum(c, &r->key);
 199
 200        data_key_init(c, &min_key, ino, min_blk);
 201        data_key_init(c, &max_key, ino, max_blk);
 202
 203        return ubifs_tnc_remove_range(c, &min_key, &max_key);
 204}
 205
 206/**
 207 * apply_replay_entry - apply a replay entry to the TNC.
 208 * @c: UBIFS file-system description object
 209 * @r: replay entry to apply
 210 *
 211 * Apply a replay entry to the TNC.
 212 */
 213static int apply_replay_entry(struct ubifs_info *c, struct replay_entry *r)
 214{
 215        int err;
 216
 217        dbg_mntk(&r->key, "LEB %d:%d len %d deletion %d sqnum %llu key ",
 218                 r->lnum, r->offs, r->len, r->deletion, r->sqnum);
 219
 220        /* Set c->replay_sqnum to help deal with dangling branches. */
 221        c->replay_sqnum = r->sqnum;
 222
 223        if (is_hash_key(c, &r->key)) {
 224                if (r->deletion)
 225                        err = ubifs_tnc_remove_nm(c, &r->key, &r->nm);
 226                else
 227                        err = ubifs_tnc_add_nm(c, &r->key, r->lnum, r->offs,
 228                                               r->len, &r->nm);
 229        } else {
 230                if (r->deletion)
 231                        switch (key_type(c, &r->key)) {
 232                        case UBIFS_INO_KEY:
 233                        {
 234                                ino_t inum = key_inum(c, &r->key);
 235
 236                                err = ubifs_tnc_remove_ino(c, inum);
 237                                break;
 238                        }
 239                        case UBIFS_TRUN_KEY:
 240                                err = trun_remove_range(c, r);
 241                                break;
 242                        default:
 243                                err = ubifs_tnc_remove(c, &r->key);
 244                                break;
 245                        }
 246                else
 247                        err = ubifs_tnc_add(c, &r->key, r->lnum, r->offs,
 248                                            r->len);
 249                if (err)
 250                        return err;
 251
 252                if (c->need_recovery)
 253                        err = ubifs_recover_size_accum(c, &r->key, r->deletion,
 254                                                       r->new_size);
 255        }
 256
 257        return err;
 258}
 259
 260/**
 261 * replay_entries_cmp - compare 2 replay entries.
 262 * @priv: UBIFS file-system description object
 263 * @a: first replay entry
 264 * @a: second replay entry
 265 *
 266 * This is a comparios function for 'list_sort()' which compares 2 replay
 267 * entries @a and @b by comparing their sequence numer.  Returns %1 if @a has
 268 * greater sequence number and %-1 otherwise.
 269 */
 270static int replay_entries_cmp(void *priv, struct list_head *a,
 271                              struct list_head *b)
 272{
 273        struct replay_entry *ra, *rb;
 274
 275        cond_resched();
 276        if (a == b)
 277                return 0;
 278
 279        ra = list_entry(a, struct replay_entry, list);
 280        rb = list_entry(b, struct replay_entry, list);
 281        ubifs_assert(ra->sqnum != rb->sqnum);
 282        if (ra->sqnum > rb->sqnum)
 283                return 1;
 284        return -1;
 285}
 286
 287/**
 288 * apply_replay_list - apply the replay list to the TNC.
 289 * @c: UBIFS file-system description object
 290 *
 291 * Apply all entries in the replay list to the TNC. Returns zero in case of
 292 * success and a negative error code in case of failure.
 293 */
 294static int apply_replay_list(struct ubifs_info *c)
 295{
 296        struct replay_entry *r;
 297        int err;
 298
 299        list_sort(c, &c->replay_list, &replay_entries_cmp);
 300
 301        list_for_each_entry(r, &c->replay_list, list) {
 302                cond_resched();
 303
 304                err = apply_replay_entry(c, r);
 305                if (err)
 306                        return err;
 307        }
 308
 309        return 0;
 310}
 311
 312/**
 313 * destroy_replay_list - destroy the replay.
 314 * @c: UBIFS file-system description object
 315 *
 316 * Destroy the replay list.
 317 */
 318static void destroy_replay_list(struct ubifs_info *c)
 319{
 320        struct replay_entry *r, *tmp;
 321
 322        list_for_each_entry_safe(r, tmp, &c->replay_list, list) {
 323                if (is_hash_key(c, &r->key))
 324                        kfree(r->nm.name);
 325                list_del(&r->list);
 326                kfree(r);
 327        }
 328}
 329
 330/**
 331 * insert_node - insert a node to the replay list
 332 * @c: UBIFS file-system description object
 333 * @lnum: node logical eraseblock number
 334 * @offs: node offset
 335 * @len: node length
 336 * @key: node key
 337 * @sqnum: sequence number
 338 * @deletion: non-zero if this is a deletion
 339 * @used: number of bytes in use in a LEB
 340 * @old_size: truncation old size
 341 * @new_size: truncation new size
 342 *
 343 * This function inserts a scanned non-direntry node to the replay list. The
 344 * replay list contains @struct replay_entry elements, and we sort this list in
 345 * sequence number order before applying it. The replay list is applied at the
 346 * very end of the replay process. Since the list is sorted in sequence number
 347 * order, the older modifications are applied first. This function returns zero
 348 * in case of success and a negative error code in case of failure.
 349 */
 350static int insert_node(struct ubifs_info *c, int lnum, int offs, int len,
 351                       union ubifs_key *key, unsigned long long sqnum,
 352                       int deletion, int *used, loff_t old_size,
 353                       loff_t new_size)
 354{
 355        struct replay_entry *r;
 356
 357        dbg_mntk(key, "add LEB %d:%d, key ", lnum, offs);
 358
 359        if (key_inum(c, key) >= c->highest_inum)
 360                c->highest_inum = key_inum(c, key);
 361
 362        r = kzalloc(sizeof(struct replay_entry), GFP_KERNEL);
 363        if (!r)
 364                return -ENOMEM;
 365
 366        if (!deletion)
 367                *used += ALIGN(len, 8);
 368        r->lnum = lnum;
 369        r->offs = offs;
 370        r->len = len;
 371        r->deletion = !!deletion;
 372        r->sqnum = sqnum;
 373        key_copy(c, key, &r->key);
 374        r->old_size = old_size;
 375        r->new_size = new_size;
 376
 377        list_add_tail(&r->list, &c->replay_list);
 378        return 0;
 379}
 380
 381/**
 382 * insert_dent - insert a directory entry node into the replay list.
 383 * @c: UBIFS file-system description object
 384 * @lnum: node logical eraseblock number
 385 * @offs: node offset
 386 * @len: node length
 387 * @key: node key
 388 * @name: directory entry name
 389 * @nlen: directory entry name length
 390 * @sqnum: sequence number
 391 * @deletion: non-zero if this is a deletion
 392 * @used: number of bytes in use in a LEB
 393 *
 394 * This function inserts a scanned directory entry node or an extended
 395 * attribute entry to the replay list. Returns zero in case of success and a
 396 * negative error code in case of failure.
 397 */
 398static int insert_dent(struct ubifs_info *c, int lnum, int offs, int len,
 399                       union ubifs_key *key, const char *name, int nlen,
 400                       unsigned long long sqnum, int deletion, int *used)
 401{
 402        struct replay_entry *r;
 403        char *nbuf;
 404
 405        dbg_mntk(key, "add LEB %d:%d, key ", lnum, offs);
 406        if (key_inum(c, key) >= c->highest_inum)
 407                c->highest_inum = key_inum(c, key);
 408
 409        r = kzalloc(sizeof(struct replay_entry), GFP_KERNEL);
 410        if (!r)
 411                return -ENOMEM;
 412
 413        nbuf = kmalloc(nlen + 1, GFP_KERNEL);
 414        if (!nbuf) {
 415                kfree(r);
 416                return -ENOMEM;
 417        }
 418
 419        if (!deletion)
 420                *used += ALIGN(len, 8);
 421        r->lnum = lnum;
 422        r->offs = offs;
 423        r->len = len;
 424        r->deletion = !!deletion;
 425        r->sqnum = sqnum;
 426        key_copy(c, key, &r->key);
 427        r->nm.len = nlen;
 428        memcpy(nbuf, name, nlen);
 429        nbuf[nlen] = '\0';
 430        r->nm.name = nbuf;
 431
 432        list_add_tail(&r->list, &c->replay_list);
 433        return 0;
 434}
 435
 436/**
 437 * ubifs_validate_entry - validate directory or extended attribute entry node.
 438 * @c: UBIFS file-system description object
 439 * @dent: the node to validate
 440 *
 441 * This function validates directory or extended attribute entry node @dent.
 442 * Returns zero if the node is all right and a %-EINVAL if not.
 443 */
 444int ubifs_validate_entry(struct ubifs_info *c,
 445                         const struct ubifs_dent_node *dent)
 446{
 447        int key_type = key_type_flash(c, dent->key);
 448        int nlen = le16_to_cpu(dent->nlen);
 449
 450        if (le32_to_cpu(dent->ch.len) != nlen + UBIFS_DENT_NODE_SZ + 1 ||
 451            dent->type >= UBIFS_ITYPES_CNT ||
 452            nlen > UBIFS_MAX_NLEN || dent->name[nlen] != 0 ||
 453            strnlen(dent->name, nlen) != nlen ||
 454            le64_to_cpu(dent->inum) > MAX_INUM) {
 455                ubifs_err(c, "bad %s node", key_type == UBIFS_DENT_KEY ?
 456                          "directory entry" : "extended attribute entry");
 457                return -EINVAL;
 458        }
 459
 460        if (key_type != UBIFS_DENT_KEY && key_type != UBIFS_XENT_KEY) {
 461                ubifs_err(c, "bad key type %d", key_type);
 462                return -EINVAL;
 463        }
 464
 465        return 0;
 466}
 467
 468/**
 469 * is_last_bud - check if the bud is the last in the journal head.
 470 * @c: UBIFS file-system description object
 471 * @bud: bud description object
 472 *
 473 * This function checks if bud @bud is the last bud in its journal head. This
 474 * information is then used by 'replay_bud()' to decide whether the bud can
 475 * have corruptions or not. Indeed, only last buds can be corrupted by power
 476 * cuts. Returns %1 if this is the last bud, and %0 if not.
 477 */
 478static int is_last_bud(struct ubifs_info *c, struct ubifs_bud *bud)
 479{
 480        struct ubifs_jhead *jh = &c->jheads[bud->jhead];
 481        struct ubifs_bud *next;
 482        uint32_t data;
 483        int err;
 484
 485        if (list_is_last(&bud->list, &jh->buds_list))
 486                return 1;
 487
 488        /*
 489         * The following is a quirk to make sure we work correctly with UBIFS
 490         * images used with older UBIFS.
 491         *
 492         * Normally, the last bud will be the last in the journal head's list
 493         * of bud. However, there is one exception if the UBIFS image belongs
 494         * to older UBIFS. This is fairly unlikely: one would need to use old
 495         * UBIFS, then have a power cut exactly at the right point, and then
 496         * try to mount this image with new UBIFS.
 497         *
 498         * The exception is: it is possible to have 2 buds A and B, A goes
 499         * before B, and B is the last, bud B is contains no data, and bud A is
 500         * corrupted at the end. The reason is that in older versions when the
 501         * journal code switched the next bud (from A to B), it first added a
 502         * log reference node for the new bud (B), and only after this it
 503         * synchronized the write-buffer of current bud (A). But later this was
 504         * changed and UBIFS started to always synchronize the write-buffer of
 505         * the bud (A) before writing the log reference for the new bud (B).
 506         *
 507         * But because older UBIFS always synchronized A's write-buffer before
 508         * writing to B, we can recognize this exceptional situation but
 509         * checking the contents of bud B - if it is empty, then A can be
 510         * treated as the last and we can recover it.
 511         *
 512         * TODO: remove this piece of code in a couple of years (today it is
 513         * 16.05.2011).
 514         */
 515        next = list_entry(bud->list.next, struct ubifs_bud, list);
 516        if (!list_is_last(&next->list, &jh->buds_list))
 517                return 0;
 518
 519        err = ubifs_leb_read(c, next->lnum, (char *)&data, next->start, 4, 1);
 520        if (err)
 521                return 0;
 522
 523        return data == 0xFFFFFFFF;
 524}
 525
 526/**
 527 * replay_bud - replay a bud logical eraseblock.
 528 * @c: UBIFS file-system description object
 529 * @b: bud entry which describes the bud
 530 *
 531 * This function replays bud @bud, recovers it if needed, and adds all nodes
 532 * from this bud to the replay list. Returns zero in case of success and a
 533 * negative error code in case of failure.
 534 */
 535static int replay_bud(struct ubifs_info *c, struct bud_entry *b)
 536{
 537        int is_last = is_last_bud(c, b->bud);
 538        int err = 0, used = 0, lnum = b->bud->lnum, offs = b->bud->start;
 539        struct ubifs_scan_leb *sleb;
 540        struct ubifs_scan_node *snod;
 541
 542        dbg_mnt("replay bud LEB %d, head %d, offs %d, is_last %d",
 543                lnum, b->bud->jhead, offs, is_last);
 544
 545        if (c->need_recovery && is_last)
 546                /*
 547                 * Recover only last LEBs in the journal heads, because power
 548                 * cuts may cause corruptions only in these LEBs, because only
 549                 * these LEBs could possibly be written to at the power cut
 550                 * time.
 551                 */
 552                sleb = ubifs_recover_leb(c, lnum, offs, c->sbuf, b->bud->jhead);
 553        else
 554                sleb = ubifs_scan(c, lnum, offs, c->sbuf, 0);
 555        if (IS_ERR(sleb))
 556                return PTR_ERR(sleb);
 557
 558        /*
 559         * The bud does not have to start from offset zero - the beginning of
 560         * the 'lnum' LEB may contain previously committed data. One of the
 561         * things we have to do in replay is to correctly update lprops with
 562         * newer information about this LEB.
 563         *
 564         * At this point lprops thinks that this LEB has 'c->leb_size - offs'
 565         * bytes of free space because it only contain information about
 566         * committed data.
 567         *
 568         * But we know that real amount of free space is 'c->leb_size -
 569         * sleb->endpt', and the space in the 'lnum' LEB between 'offs' and
 570         * 'sleb->endpt' is used by bud data. We have to correctly calculate
 571         * how much of these data are dirty and update lprops with this
 572         * information.
 573         *
 574         * The dirt in that LEB region is comprised of padding nodes, deletion
 575         * nodes, truncation nodes and nodes which are obsoleted by subsequent
 576         * nodes in this LEB. So instead of calculating clean space, we
 577         * calculate used space ('used' variable).
 578         */
 579
 580        list_for_each_entry(snod, &sleb->nodes, list) {
 581                int deletion = 0;
 582
 583                cond_resched();
 584
 585                if (snod->sqnum >= SQNUM_WATERMARK) {
 586                        ubifs_err(c, "file system's life ended");
 587                        goto out_dump;
 588                }
 589
 590                if (snod->sqnum > c->max_sqnum)
 591                        c->max_sqnum = snod->sqnum;
 592
 593                switch (snod->type) {
 594                case UBIFS_INO_NODE:
 595                {
 596                        struct ubifs_ino_node *ino = snod->node;
 597                        loff_t new_size = le64_to_cpu(ino->size);
 598
 599                        if (le32_to_cpu(ino->nlink) == 0)
 600                                deletion = 1;
 601                        err = insert_node(c, lnum, snod->offs, snod->len,
 602                                          &snod->key, snod->sqnum, deletion,
 603                                          &used, 0, new_size);
 604                        break;
 605                }
 606                case UBIFS_DATA_NODE:
 607                {
 608                        struct ubifs_data_node *dn = snod->node;
 609                        loff_t new_size = le32_to_cpu(dn->size) +
 610                                          key_block(c, &snod->key) *
 611                                          UBIFS_BLOCK_SIZE;
 612
 613                        err = insert_node(c, lnum, snod->offs, snod->len,
 614                                          &snod->key, snod->sqnum, deletion,
 615                                          &used, 0, new_size);
 616                        break;
 617                }
 618                case UBIFS_DENT_NODE:
 619                case UBIFS_XENT_NODE:
 620                {
 621                        struct ubifs_dent_node *dent = snod->node;
 622
 623                        err = ubifs_validate_entry(c, dent);
 624                        if (err)
 625                                goto out_dump;
 626
 627                        err = insert_dent(c, lnum, snod->offs, snod->len,
 628                                          &snod->key, dent->name,
 629                                          le16_to_cpu(dent->nlen), snod->sqnum,
 630                                          !le64_to_cpu(dent->inum), &used);
 631                        break;
 632                }
 633                case UBIFS_TRUN_NODE:
 634                {
 635                        struct ubifs_trun_node *trun = snod->node;
 636                        loff_t old_size = le64_to_cpu(trun->old_size);
 637                        loff_t new_size = le64_to_cpu(trun->new_size);
 638                        union ubifs_key key;
 639
 640                        /* Validate truncation node */
 641                        if (old_size < 0 || old_size > c->max_inode_sz ||
 642                            new_size < 0 || new_size > c->max_inode_sz ||
 643                            old_size <= new_size) {
 644                                ubifs_err(c, "bad truncation node");
 645                                goto out_dump;
 646                        }
 647
 648                        /*
 649                         * Create a fake truncation key just to use the same
 650                         * functions which expect nodes to have keys.
 651                         */
 652                        trun_key_init(c, &key, le32_to_cpu(trun->inum));
 653                        err = insert_node(c, lnum, snod->offs, snod->len,
 654                                          &key, snod->sqnum, 1, &used,
 655                                          old_size, new_size);
 656                        break;
 657                }
 658                default:
 659                        ubifs_err(c, "unexpected node type %d in bud LEB %d:%d",
 660                                  snod->type, lnum, snod->offs);
 661                        err = -EINVAL;
 662                        goto out_dump;
 663                }
 664                if (err)
 665                        goto out;
 666        }
 667
 668        ubifs_assert(ubifs_search_bud(c, lnum));
 669        ubifs_assert(sleb->endpt - offs >= used);
 670        ubifs_assert(sleb->endpt % c->min_io_size == 0);
 671
 672        b->dirty = sleb->endpt - offs - used;
 673        b->free = c->leb_size - sleb->endpt;
 674        dbg_mnt("bud LEB %d replied: dirty %d, free %d",
 675                lnum, b->dirty, b->free);
 676
 677out:
 678        ubifs_scan_destroy(sleb);
 679        return err;
 680
 681out_dump:
 682        ubifs_err(c, "bad node is at LEB %d:%d", lnum, snod->offs);
 683        ubifs_dump_node(c, snod->node);
 684        ubifs_scan_destroy(sleb);
 685        return -EINVAL;
 686}
 687
 688/**
 689 * replay_buds - replay all buds.
 690 * @c: UBIFS file-system description object
 691 *
 692 * This function returns zero in case of success and a negative error code in
 693 * case of failure.
 694 */
 695static int replay_buds(struct ubifs_info *c)
 696{
 697        struct bud_entry *b;
 698        int err;
 699        unsigned long long prev_sqnum = 0;
 700
 701        list_for_each_entry(b, &c->replay_buds, list) {
 702                err = replay_bud(c, b);
 703                if (err)
 704                        return err;
 705
 706                ubifs_assert(b->sqnum > prev_sqnum);
 707                prev_sqnum = b->sqnum;
 708        }
 709
 710        return 0;
 711}
 712
 713/**
 714 * destroy_bud_list - destroy the list of buds to replay.
 715 * @c: UBIFS file-system description object
 716 */
 717static void destroy_bud_list(struct ubifs_info *c)
 718{
 719        struct bud_entry *b;
 720
 721        while (!list_empty(&c->replay_buds)) {
 722                b = list_entry(c->replay_buds.next, struct bud_entry, list);
 723                list_del(&b->list);
 724                kfree(b);
 725        }
 726}
 727
 728/**
 729 * add_replay_bud - add a bud to the list of buds to replay.
 730 * @c: UBIFS file-system description object
 731 * @lnum: bud logical eraseblock number to replay
 732 * @offs: bud start offset
 733 * @jhead: journal head to which this bud belongs
 734 * @sqnum: reference node sequence number
 735 *
 736 * This function returns zero in case of success and a negative error code in
 737 * case of failure.
 738 */
 739static int add_replay_bud(struct ubifs_info *c, int lnum, int offs, int jhead,
 740                          unsigned long long sqnum)
 741{
 742        struct ubifs_bud *bud;
 743        struct bud_entry *b;
 744
 745        dbg_mnt("add replay bud LEB %d:%d, head %d", lnum, offs, jhead);
 746
 747        bud = kmalloc(sizeof(struct ubifs_bud), GFP_KERNEL);
 748        if (!bud)
 749                return -ENOMEM;
 750
 751        b = kmalloc(sizeof(struct bud_entry), GFP_KERNEL);
 752        if (!b) {
 753                kfree(bud);
 754                return -ENOMEM;
 755        }
 756
 757        bud->lnum = lnum;
 758        bud->start = offs;
 759        bud->jhead = jhead;
 760        ubifs_add_bud(c, bud);
 761
 762        b->bud = bud;
 763        b->sqnum = sqnum;
 764        list_add_tail(&b->list, &c->replay_buds);
 765
 766        return 0;
 767}
 768
 769/**
 770 * validate_ref - validate a reference node.
 771 * @c: UBIFS file-system description object
 772 * @ref: the reference node to validate
 773 * @ref_lnum: LEB number of the reference node
 774 * @ref_offs: reference node offset
 775 *
 776 * This function returns %1 if a bud reference already exists for the LEB. %0 is
 777 * returned if the reference node is new, otherwise %-EINVAL is returned if
 778 * validation failed.
 779 */
 780static int validate_ref(struct ubifs_info *c, const struct ubifs_ref_node *ref)
 781{
 782        struct ubifs_bud *bud;
 783        int lnum = le32_to_cpu(ref->lnum);
 784        unsigned int offs = le32_to_cpu(ref->offs);
 785        unsigned int jhead = le32_to_cpu(ref->jhead);
 786
 787        /*
 788         * ref->offs may point to the end of LEB when the journal head points
 789         * to the end of LEB and we write reference node for it during commit.
 790         * So this is why we require 'offs > c->leb_size'.
 791         */
 792        if (jhead >= c->jhead_cnt || lnum >= c->leb_cnt ||
 793            lnum < c->main_first || offs > c->leb_size ||
 794            offs & (c->min_io_size - 1))
 795                return -EINVAL;
 796
 797        /* Make sure we have not already looked at this bud */
 798        bud = ubifs_search_bud(c, lnum);
 799        if (bud) {
 800                if (bud->jhead == jhead && bud->start <= offs)
 801                        return 1;
 802                ubifs_err(c, "bud at LEB %d:%d was already referred", lnum, offs);
 803                return -EINVAL;
 804        }
 805
 806        return 0;
 807}
 808
 809/**
 810 * replay_log_leb - replay a log logical eraseblock.
 811 * @c: UBIFS file-system description object
 812 * @lnum: log logical eraseblock to replay
 813 * @offs: offset to start replaying from
 814 * @sbuf: scan buffer
 815 *
 816 * This function replays a log LEB and returns zero in case of success, %1 if
 817 * this is the last LEB in the log, and a negative error code in case of
 818 * failure.
 819 */
 820static int replay_log_leb(struct ubifs_info *c, int lnum, int offs, void *sbuf)
 821{
 822        int err;
 823        struct ubifs_scan_leb *sleb;
 824        struct ubifs_scan_node *snod;
 825        const struct ubifs_cs_node *node;
 826
 827        dbg_mnt("replay log LEB %d:%d", lnum, offs);
 828        sleb = ubifs_scan(c, lnum, offs, sbuf, c->need_recovery);
 829        if (IS_ERR(sleb)) {
 830                if (PTR_ERR(sleb) != -EUCLEAN || !c->need_recovery)
 831                        return PTR_ERR(sleb);
 832                /*
 833                 * Note, the below function will recover this log LEB only if
 834                 * it is the last, because unclean reboots can possibly corrupt
 835                 * only the tail of the log.
 836                 */
 837                sleb = ubifs_recover_log_leb(c, lnum, offs, sbuf);
 838                if (IS_ERR(sleb))
 839                        return PTR_ERR(sleb);
 840        }
 841
 842        if (sleb->nodes_cnt == 0) {
 843                err = 1;
 844                goto out;
 845        }
 846
 847        node = sleb->buf;
 848        snod = list_entry(sleb->nodes.next, struct ubifs_scan_node, list);
 849        if (c->cs_sqnum == 0) {
 850                /*
 851                 * This is the first log LEB we are looking at, make sure that
 852                 * the first node is a commit start node. Also record its
 853                 * sequence number so that UBIFS can determine where the log
 854                 * ends, because all nodes which were have higher sequence
 855                 * numbers.
 856                 */
 857                if (snod->type != UBIFS_CS_NODE) {
 858                        ubifs_err(c, "first log node at LEB %d:%d is not CS node",
 859                                  lnum, offs);
 860                        goto out_dump;
 861                }
 862                if (le64_to_cpu(node->cmt_no) != c->cmt_no) {
 863                        ubifs_err(c, "first CS node at LEB %d:%d has wrong commit number %llu expected %llu",
 864                                  lnum, offs,
 865                                  (unsigned long long)le64_to_cpu(node->cmt_no),
 866                                  c->cmt_no);
 867                        goto out_dump;
 868                }
 869
 870                c->cs_sqnum = le64_to_cpu(node->ch.sqnum);
 871                dbg_mnt("commit start sqnum %llu", c->cs_sqnum);
 872        }
 873
 874        if (snod->sqnum < c->cs_sqnum) {
 875                /*
 876                 * This means that we reached end of log and now
 877                 * look to the older log data, which was already
 878                 * committed but the eraseblock was not erased (UBIFS
 879                 * only un-maps it). So this basically means we have to
 880                 * exit with "end of log" code.
 881                 */
 882                err = 1;
 883                goto out;
 884        }
 885
 886        /* Make sure the first node sits at offset zero of the LEB */
 887        if (snod->offs != 0) {
 888                ubifs_err(c, "first node is not at zero offset");
 889                goto out_dump;
 890        }
 891
 892        list_for_each_entry(snod, &sleb->nodes, list) {
 893                cond_resched();
 894
 895                if (snod->sqnum >= SQNUM_WATERMARK) {
 896                        ubifs_err(c, "file system's life ended");
 897                        goto out_dump;
 898                }
 899
 900                if (snod->sqnum < c->cs_sqnum) {
 901                        ubifs_err(c, "bad sqnum %llu, commit sqnum %llu",
 902                                  snod->sqnum, c->cs_sqnum);
 903                        goto out_dump;
 904                }
 905
 906                if (snod->sqnum > c->max_sqnum)
 907                        c->max_sqnum = snod->sqnum;
 908
 909                switch (snod->type) {
 910                case UBIFS_REF_NODE: {
 911                        const struct ubifs_ref_node *ref = snod->node;
 912
 913                        err = validate_ref(c, ref);
 914                        if (err == 1)
 915                                break; /* Already have this bud */
 916                        if (err)
 917                                goto out_dump;
 918
 919                        err = add_replay_bud(c, le32_to_cpu(ref->lnum),
 920                                             le32_to_cpu(ref->offs),
 921                                             le32_to_cpu(ref->jhead),
 922                                             snod->sqnum);
 923                        if (err)
 924                                goto out;
 925
 926                        break;
 927                }
 928                case UBIFS_CS_NODE:
 929                        /* Make sure it sits at the beginning of LEB */
 930                        if (snod->offs != 0) {
 931                                ubifs_err(c, "unexpected node in log");
 932                                goto out_dump;
 933                        }
 934                        break;
 935                default:
 936                        ubifs_err(c, "unexpected node in log");
 937                        goto out_dump;
 938                }
 939        }
 940
 941        if (sleb->endpt || c->lhead_offs >= c->leb_size) {
 942                c->lhead_lnum = lnum;
 943                c->lhead_offs = sleb->endpt;
 944        }
 945
 946        err = !sleb->endpt;
 947out:
 948        ubifs_scan_destroy(sleb);
 949        return err;
 950
 951out_dump:
 952        ubifs_err(c, "log error detected while replaying the log at LEB %d:%d",
 953                  lnum, offs + snod->offs);
 954        ubifs_dump_node(c, snod->node);
 955        ubifs_scan_destroy(sleb);
 956        return -EINVAL;
 957}
 958
 959/**
 960 * take_ihead - update the status of the index head in lprops to 'taken'.
 961 * @c: UBIFS file-system description object
 962 *
 963 * This function returns the amount of free space in the index head LEB or a
 964 * negative error code.
 965 */
 966static int take_ihead(struct ubifs_info *c)
 967{
 968        const struct ubifs_lprops *lp;
 969        int err, free;
 970
 971        ubifs_get_lprops(c);
 972
 973        lp = ubifs_lpt_lookup_dirty(c, c->ihead_lnum);
 974        if (IS_ERR(lp)) {
 975                err = PTR_ERR(lp);
 976                goto out;
 977        }
 978
 979        free = lp->free;
 980
 981        lp = ubifs_change_lp(c, lp, LPROPS_NC, LPROPS_NC,
 982                             lp->flags | LPROPS_TAKEN, 0);
 983        if (IS_ERR(lp)) {
 984                err = PTR_ERR(lp);
 985                goto out;
 986        }
 987
 988        err = free;
 989out:
 990        ubifs_release_lprops(c);
 991        return err;
 992}
 993
 994/**
 995 * ubifs_replay_journal - replay journal.
 996 * @c: UBIFS file-system description object
 997 *
 998 * This function scans the journal, replays and cleans it up. It makes sure all
 999 * memory data structures related to uncommitted journal are built (dirty TNC
1000 * tree, tree of buds, modified lprops, etc).
1001 */
1002int ubifs_replay_journal(struct ubifs_info *c)
1003{
1004        int err, lnum, free;
1005
1006        BUILD_BUG_ON(UBIFS_TRUN_KEY > 5);
1007
1008        /* Update the status of the index head in lprops to 'taken' */
1009        free = take_ihead(c);
1010        if (free < 0)
1011                return free; /* Error code */
1012
1013        if (c->ihead_offs != c->leb_size - free) {
1014                ubifs_err(c, "bad index head LEB %d:%d", c->ihead_lnum,
1015                          c->ihead_offs);
1016                return -EINVAL;
1017        }
1018
1019        dbg_mnt("start replaying the journal");
1020        c->replaying = 1;
1021        lnum = c->ltail_lnum = c->lhead_lnum;
1022
1023        do {
1024                err = replay_log_leb(c, lnum, 0, c->sbuf);
1025                if (err == 1) {
1026                        if (lnum != c->lhead_lnum)
1027                                /* We hit the end of the log */
1028                                break;
1029
1030                        /*
1031                         * The head of the log must always start with the
1032                         * "commit start" node on a properly formatted UBIFS.
1033                         * But we found no nodes at all, which means that
1034                         * someting went wrong and we cannot proceed mounting
1035                         * the file-system.
1036                         */
1037                        ubifs_err(c, "no UBIFS nodes found at the log head LEB %d:%d, possibly corrupted",
1038                                  lnum, 0);
1039                        err = -EINVAL;
1040                }
1041                if (err)
1042                        goto out;
1043                lnum = ubifs_next_log_lnum(c, lnum);
1044        } while (lnum != c->ltail_lnum);
1045
1046        err = replay_buds(c);
1047        if (err)
1048                goto out;
1049
1050        err = apply_replay_list(c);
1051        if (err)
1052                goto out;
1053
1054        err = set_buds_lprops(c);
1055        if (err)
1056                goto out;
1057
1058        /*
1059         * UBIFS budgeting calculations use @c->bi.uncommitted_idx variable
1060         * to roughly estimate index growth. Things like @c->bi.min_idx_lebs
1061         * depend on it. This means we have to initialize it to make sure
1062         * budgeting works properly.
1063         */
1064        c->bi.uncommitted_idx = atomic_long_read(&c->dirty_zn_cnt);
1065        c->bi.uncommitted_idx *= c->max_idx_node_sz;
1066
1067        ubifs_assert(c->bud_bytes <= c->max_bud_bytes || c->need_recovery);
1068        dbg_mnt("finished, log head LEB %d:%d, max_sqnum %llu, highest_inum %lu",
1069                c->lhead_lnum, c->lhead_offs, c->max_sqnum,
1070                (unsigned long)c->highest_inum);
1071out:
1072        destroy_replay_list(c);
1073        destroy_bud_list(c);
1074        c->replaying = 0;
1075        return err;
1076}
1077