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 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * This file is part of UBIFS.
  *
  * Copyright (C) 2006-2008 Nokia Corporation.
  *
  * Authors: Adrian Hunter
  *          Artem Bityutskiy (Битюцкий Артём)
  */
 
 /*
  * This file contains journal replay code. It runs when the file-system is being
  * mounted and requires no locking.
  *
  * The larger is the journal, the longer it takes to scan it, so the longer it
  * takes to mount UBIFS. This is why the journal has limited size which may be
  * changed depending on the system requirements. But a larger journal gives
  * faster I/O speed because it writes the index less frequently. So this is a
  * trade-off. Also, the journal is indexed by the in-memory index (TNC), so the
  * larger is the journal, the more memory its index may consume.
  */
 
 #include "ubifs.h"
 #include <linux/list_sort.h>
 #include <crypto/hash.h>
 #include <crypto/algapi.h>
 
 /**
  * struct replay_entry - replay list entry.
  * @lnum: logical eraseblock number of the node
  * @offs: node offset
  * @len: node length
  * @deletion: non-zero if this entry corresponds to a node deletion
  * @sqnum: node sequence number
  * @list: links the replay list
  * @key: node key
  * @nm: directory entry name
  * @old_size: truncation old size
  * @new_size: truncation new size
  *
  * The replay process first scans all buds and builds the replay list, then
  * sorts the replay list in nodes sequence number order, and then inserts all
  * the replay entries to the TNC.
  */
 struct replay_entry {
     int lnum;
     int offs;
     int len;
     u8 hash[UBIFS_HASH_ARR_SZ];
     unsigned int deletion:1;
     unsigned long long sqnum;
     struct list_head list;
     union ubifs_key key;
     union {
         struct fscrypt_name nm;
         struct {
             loff_t old_size;
             loff_t new_size;
         };
     };
 };
 
 /**
  * struct bud_entry - entry in the list of buds to replay.
  * @list: next bud in the list
  * @bud: bud description object
  * @sqnum: reference node sequence number
  * @free: free bytes in the bud
  * @dirty: dirty bytes in the bud
  */
 struct bud_entry {
     struct list_head list;
     struct ubifs_bud *bud;
     unsigned long long sqnum;
     int free;
     int dirty;
 };
 
 /**
  * set_bud_lprops - set free and dirty space used by a bud.
  * @c: UBIFS file-system description object
  * @b: bud entry which describes the bud
  *
  * This function makes sure the LEB properties of bud @b are set correctly
  * after the replay. Returns zero in case of success and a negative error code
  * in case of failure.
  */
 static int set_bud_lprops(struct ubifs_info *c, struct bud_entry *b)
 {
     const struct ubifs_lprops *lp;
     int err = 0, dirty;
 
     ubifs_get_lprops(c);
 
     lp = ubifs_lpt_lookup_dirty(c, b->bud->lnum);
     if (IS_ERR(lp)) {
         err = PTR_ERR(lp);
         goto out;
     }
 
     dirty = lp->dirty;
     if (b->bud->start == 0 && (lp->free != c->leb_size || lp->dirty != 0)) {
         /*
          * The LEB was added to the journal with a starting offset of
          * zero which means the LEB must have been empty. The LEB
          * property values should be @lp->free == @c->leb_size and
          * @lp->dirty == 0, but that is not the case. The reason is that
          * the LEB had been garbage collected before it became the bud,
          * and there was no commit in between. The garbage collector
          * resets the free and dirty space without recording it
          * anywhere except lprops, so if there was no commit then
          * lprops does not have that information.
          *
          * We do not need to adjust free space because the scan has told
          * us the exact value which is recorded in the replay entry as
          * @b->free.
          *
          * However we do need to subtract from the dirty space the
          * amount of space that the garbage collector reclaimed, which
          * is the whole LEB minus the amount of space that was free.
          */
         dbg_mnt("bud LEB %d was GC'd (%d free, %d dirty)", b->bud->lnum,
             lp->free, lp->dirty);
         dbg_gc("bud LEB %d was GC'd (%d free, %d dirty)", b->bud->lnum,
             lp->free, lp->dirty);
         dirty -= c->leb_size - lp->free;
         /*
          * If the replay order was perfect the dirty space would now be
          * zero. The order is not perfect because the journal heads
          * race with each other. This is not a problem but is does mean
          * that the dirty space may temporarily exceed c->leb_size
          * during the replay.
          */
         if (dirty != 0)
             dbg_mnt("LEB %d lp: %d free %d dirty replay: %d free %d dirty",
                 b->bud->lnum, lp->free, lp->dirty, b->free,
                 b->dirty);
     }
     lp = ubifs_change_lp(c, lp, b->free, dirty + b->dirty,
                  lp->flags | LPROPS_TAKEN, 0);
     if (IS_ERR(lp)) {
         err = PTR_ERR(lp);
         goto out;
     }
 
     /* Make sure the journal head points to the latest bud */
     err = ubifs_wbuf_seek_nolock(&c->jheads[b->bud->jhead].wbuf,
                      b->bud->lnum, c->leb_size - b->free);
 
 out:
     ubifs_release_lprops(c);
     return err;
 }
 
 /**
  * set_buds_lprops - set free and dirty space for all replayed buds.
  * @c: UBIFS file-system description object
  *
  * This function sets LEB properties for all replayed buds. Returns zero in
  * case of success and a negative error code in case of failure.
  */
 static int set_buds_lprops(struct ubifs_info *c)
 {
     struct bud_entry *b;
     int err;
 
     list_for_each_entry(b, &c->replay_buds, list) {
         err = set_bud_lprops(c, b);
         if (err)
             return err;
     }
 
     return 0;
 }
 
 /**
  * trun_remove_range - apply a replay entry for a truncation to the TNC.
  * @c: UBIFS file-system description object
  * @r: replay entry of truncation
  */
 static int trun_remove_range(struct ubifs_info *c, struct replay_entry *r)
 {
     unsigned min_blk, max_blk;
     union ubifs_key min_key, max_key;
     ino_t ino;
 
     min_blk = r->new_size / UBIFS_BLOCK_SIZE;
     if (r->new_size & (UBIFS_BLOCK_SIZE - 1))
         min_blk += 1;
 
     max_blk = r->old_size / UBIFS_BLOCK_SIZE;
     if ((r->old_size & (UBIFS_BLOCK_SIZE - 1)) == 0)
         max_blk -= 1;
 
     ino = key_inum(c, &r->key);
 
     data_key_init(c, &min_key, ino, min_blk);
     data_key_init(c, &max_key, ino, max_blk);
 
     return ubifs_tnc_remove_range(c, &min_key, &max_key);
 }
 
 /**
  * inode_still_linked - check whether inode in question will be re-linked.
  * @c: UBIFS file-system description object
  * @rino: replay entry to test
  *
  * O_TMPFILE files can be re-linked, this means link count goes from 0 to 1.
  * This case needs special care, otherwise all references to the inode will
  * be removed upon the first replay entry of an inode with link count 0
  * is found.
  */
 static bool inode_still_linked(struct ubifs_info *c, struct replay_entry *rino)
 {
     struct replay_entry *r;
 
     ubifs_assert(c, rino->deletion);
     ubifs_assert(c, key_type(c, &rino->key) == UBIFS_INO_KEY);
 
     /*
      * Find the most recent entry for the inode behind @rino and check
      * whether it is a deletion.
      */
     list_for_each_entry_reverse(r, &c->replay_list, list) {
         ubifs_assert(c, r->sqnum >= rino->sqnum);
         if (key_inum(c, &r->key) == key_inum(c, &rino->key) &&
             key_type(c, &r->key) == UBIFS_INO_KEY)
             return r->deletion == 0;
 
     }
 
     ubifs_assert(c, 0);
     return false;
 }
 
 /**
  * apply_replay_entry - apply a replay entry to the TNC.
  * @c: UBIFS file-system description object
  * @r: replay entry to apply
  *
  * Apply a replay entry to the TNC.
  */
 static int apply_replay_entry(struct ubifs_info *c, struct replay_entry *r)
 {
     int err;
 
     dbg_mntk(&r->key, "LEB %d:%d len %d deletion %d sqnum %llu key ",
          r->lnum, r->offs, r->len, r->deletion, r->sqnum);
 
     if (is_hash_key(c, &r->key)) {
         if (r->deletion)
             err = ubifs_tnc_remove_nm(c, &r->key, &r->nm);
         else
             err = ubifs_tnc_add_nm(c, &r->key, r->lnum, r->offs,
                            r->len, r->hash, &r->nm);
     } else {
         if (r->deletion)
             switch (key_type(c, &r->key)) {
             case UBIFS_INO_KEY:
             {
                 ino_t inum = key_inum(c, &r->key);
 
                 if (inode_still_linked(c, r)) {
                     err = 0;
                     break;
                 }
 
                 err = ubifs_tnc_remove_ino(c, inum);
                 break;
             }
             case UBIFS_TRUN_KEY:
                 err = trun_remove_range(c, r);
                 break;
             default:
                 err = ubifs_tnc_remove(c, &r->key);
                 break;
             }
         else
             err = ubifs_tnc_add(c, &r->key, r->lnum, r->offs,
                         r->len, r->hash);
         if (err)
             return err;
 
         if (c->need_recovery)
             err = ubifs_recover_size_accum(c, &r->key, r->deletion,
                                r->new_size);
     }
 
     return err;
 }
 
 /**
  * replay_entries_cmp - compare 2 replay entries.
  * @priv: UBIFS file-system description object
  * @a: first replay entry
  * @b: second replay entry
  *
  * This is a comparios function for 'list_sort()' which compares 2 replay
  * entries @a and @b by comparing their sequence number.  Returns %1 if @a has
  * greater sequence number and %-1 otherwise.
  */
 static int replay_entries_cmp(void *priv, const struct list_head *a,
                   const struct list_head *b)
 {
     struct ubifs_info *c = priv;
     struct replay_entry *ra, *rb;
 
     cond_resched();
     if (a == b)
         return 0;
 
     ra = list_entry(a, struct replay_entry, list);
     rb = list_entry(b, struct replay_entry, list);
     ubifs_assert(c, ra->sqnum != rb->sqnum);
     if (ra->sqnum > rb->sqnum)
         return 1;
     return -1;
 }
 
 /**
  * apply_replay_list - apply the replay list to the TNC.
  * @c: UBIFS file-system description object
  *
  * Apply all entries in the replay list to the TNC. Returns zero in case of
  * success and a negative error code in case of failure.
  */
 static int apply_replay_list(struct ubifs_info *c)
 {
     struct replay_entry *r;
     int err;
 
     list_sort(c, &c->replay_list, &replay_entries_cmp);
 
     list_for_each_entry(r, &c->replay_list, list) {
         cond_resched();
 
         err = apply_replay_entry(c, r);
         if (err)
             return err;
     }
 
     return 0;
 }
 
 /**
  * destroy_replay_list - destroy the replay.
  * @c: UBIFS file-system description object
  *
  * Destroy the replay list.
  */
 static void destroy_replay_list(struct ubifs_info *c)
 {
     struct replay_entry *r, *tmp;
 
     list_for_each_entry_safe(r, tmp, &c->replay_list, list) {
         if (is_hash_key(c, &r->key))
             kfree(fname_name(&r->nm));
         list_del(&r->list);
         kfree(r);
     }
 }
 
 /**
  * insert_node - insert a node to the replay list
  * @c: UBIFS file-system description object
  * @lnum: node logical eraseblock number
  * @offs: node offset
  * @len: node length
  * @key: node key
  * @sqnum: sequence number
  * @deletion: non-zero if this is a deletion
  * @used: number of bytes in use in a LEB
  * @old_size: truncation old size
  * @new_size: truncation new size
  *
  * This function inserts a scanned non-direntry node to the replay list. The
  * replay list contains @struct replay_entry elements, and we sort this list in
  * sequence number order before applying it. The replay list is applied at the
  * very end of the replay process. Since the list is sorted in sequence number
  * order, the older modifications are applied first. This function returns zero
  * in case of success and a negative error code in case of failure.
  */
 static int insert_node(struct ubifs_info *c, int lnum, int offs, int len,
                const u8 *hash, union ubifs_key *key,
                unsigned long long sqnum, int deletion, int *used,
                loff_t old_size, loff_t new_size)
 {
     struct replay_entry *r;
 
     dbg_mntk(key, "add LEB %d:%d, key ", lnum, offs);
 
     if (key_inum(c, key) >= c->highest_inum)
         c->highest_inum = key_inum(c, key);
 
     r = kzalloc(sizeof(struct replay_entry), GFP_KERNEL);
     if (!r)
         return -ENOMEM;
 
     if (!deletion)
         *used += ALIGN(len, 8);
     r->lnum = lnum;
     r->offs = offs;
     r->len = len;
     ubifs_copy_hash(c, hash, r->hash);
     r->deletion = !!deletion;
     r->sqnum = sqnum;
     key_copy(c, key, &r->key);
     r->old_size = old_size;
     r->new_size = new_size;
 
     list_add_tail(&r->list, &c->replay_list);
     return 0;
 }
 
 /**
  * insert_dent - insert a directory entry node into the replay list.
  * @c: UBIFS file-system description object
  * @lnum: node logical eraseblock number
  * @offs: node offset
  * @len: node length
  * @key: node key
  * @name: directory entry name
  * @nlen: directory entry name length
  * @sqnum: sequence number
  * @deletion: non-zero if this is a deletion
  * @used: number of bytes in use in a LEB
  *
  * This function inserts a scanned directory entry node or an extended
  * attribute entry to the replay list. Returns zero in case of success and a
  * negative error code in case of failure.
  */
 static int insert_dent(struct ubifs_info *c, int lnum, int offs, int len,
                const u8 *hash, union ubifs_key *key,
                const char *name, int nlen, unsigned long long sqnum,
                int deletion, int *used)
 {
     struct replay_entry *r;
     char *nbuf;
 
     dbg_mntk(key, "add LEB %d:%d, key ", lnum, offs);
     if (key_inum(c, key) >= c->highest_inum)
         c->highest_inum = key_inum(c, key);
 
     r = kzalloc(sizeof(struct replay_entry), GFP_KERNEL);
     if (!r)
         return -ENOMEM;
 
     nbuf = kmalloc(nlen + 1, GFP_KERNEL);
     if (!nbuf) {
         kfree(r);
         return -ENOMEM;
     }
 
     if (!deletion)
         *used += ALIGN(len, 8);
     r->lnum = lnum;
     r->offs = offs;
     r->len = len;
     ubifs_copy_hash(c, hash, r->hash);
     r->deletion = !!deletion;
     r->sqnum = sqnum;
     key_copy(c, key, &r->key);
     fname_len(&r->nm) = nlen;
     memcpy(nbuf, name, nlen);
     nbuf[nlen] = '\0';
     fname_name(&r->nm) = nbuf;
 
     list_add_tail(&r->list, &c->replay_list);
     return 0;
 }
 
 /**
  * ubifs_validate_entry - validate directory or extended attribute entry node.
  * @c: UBIFS file-system description object
  * @dent: the node to validate
  *
  * This function validates directory or extended attribute entry node @dent.
  * Returns zero if the node is all right and a %-EINVAL if not.
  */
 int ubifs_validate_entry(struct ubifs_info *c,
              const struct ubifs_dent_node *dent)
 {
     int key_type = key_type_flash(c, dent->key);
     int nlen = le16_to_cpu(dent->nlen);
 
     if (le32_to_cpu(dent->ch.len) != nlen + UBIFS_DENT_NODE_SZ + 1 ||
         dent->type >= UBIFS_ITYPES_CNT ||
         nlen > UBIFS_MAX_NLEN || dent->name[nlen] != 0 ||
         (key_type == UBIFS_XENT_KEY && strnlen(dent->name, nlen) != nlen) ||
         le64_to_cpu(dent->inum) > MAX_INUM) {
         ubifs_err(c, "bad %s node", key_type == UBIFS_DENT_KEY ?
               "directory entry" : "extended attribute entry");
         return -EINVAL;
     }
 
     if (key_type != UBIFS_DENT_KEY && key_type != UBIFS_XENT_KEY) {
         ubifs_err(c, "bad key type %d", key_type);
         return -EINVAL;
     }
 
     return 0;
 }
 
 /**
  * is_last_bud - check if the bud is the last in the journal head.
  * @c: UBIFS file-system description object
  * @bud: bud description object
  *
  * This function checks if bud @bud is the last bud in its journal head. This
  * information is then used by 'replay_bud()' to decide whether the bud can
  * have corruptions or not. Indeed, only last buds can be corrupted by power
  * cuts. Returns %1 if this is the last bud, and %0 if not.
  */
 static int is_last_bud(struct ubifs_info *c, struct ubifs_bud *bud)
 {
     struct ubifs_jhead *jh = &c->jheads[bud->jhead];
     struct ubifs_bud *next;
     uint32_t data;
     int err;
 
     if (list_is_last(&bud->list, &jh->buds_list))
         return 1;
 
     /*
      * The following is a quirk to make sure we work correctly with UBIFS
      * images used with older UBIFS.
      *
      * Normally, the last bud will be the last in the journal head's list
      * of bud. However, there is one exception if the UBIFS image belongs
      * to older UBIFS. This is fairly unlikely: one would need to use old
      * UBIFS, then have a power cut exactly at the right point, and then
      * try to mount this image with new UBIFS.
      *
      * The exception is: it is possible to have 2 buds A and B, A goes
      * before B, and B is the last, bud B is contains no data, and bud A is
      * corrupted at the end. The reason is that in older versions when the
      * journal code switched the next bud (from A to B), it first added a
      * log reference node for the new bud (B), and only after this it
      * synchronized the write-buffer of current bud (A). But later this was
      * changed and UBIFS started to always synchronize the write-buffer of
      * the bud (A) before writing the log reference for the new bud (B).
      *
      * But because older UBIFS always synchronized A's write-buffer before
      * writing to B, we can recognize this exceptional situation but
      * checking the contents of bud B - if it is empty, then A can be
      * treated as the last and we can recover it.
      *
      * TODO: remove this piece of code in a couple of years (today it is
      * 16.05.2011).
      */
     next = list_entry(bud->list.next, struct ubifs_bud, list);
     if (!list_is_last(&next->list, &jh->buds_list))
         return 0;
 
     err = ubifs_leb_read(c, next->lnum, (char *)&data, next->start, 4, 1);
     if (err)
         return 0;
 
     return data == 0xFFFFFFFF;
 }
 
 /* authenticate_sleb_hash is split out for stack usage */
 static int noinline_for_stack
 authenticate_sleb_hash(struct ubifs_info *c,
                struct shash_desc *log_hash, u8 *hash)
 {
     SHASH_DESC_ON_STACK(hash_desc, c->hash_tfm);
 
     hash_desc->tfm = c->hash_tfm;
 
     ubifs_shash_copy_state(c, log_hash, hash_desc);
     return crypto_shash_final(hash_desc, hash);
 }
 
 /**
  * authenticate_sleb - authenticate one scan LEB
  * @c: UBIFS file-system description object
  * @sleb: the scan LEB to authenticate
  * @log_hash:
  * @is_last: if true, this is the last LEB
  *
  * This function iterates over the buds of a single LEB authenticating all buds
  * with the authentication nodes on this LEB. Authentication nodes are written
  * after some buds and contain a HMAC covering the authentication node itself
  * and the buds between the last authentication node and the current
  * authentication node. It can happen that the last buds cannot be authenticated
  * because a powercut happened when some nodes were written but not the
  * corresponding authentication node. This function returns the number of nodes
  * that could be authenticated or a negative error code.
  */
 static int authenticate_sleb(struct ubifs_info *c, struct ubifs_scan_leb *sleb,
                  struct shash_desc *log_hash, int is_last)
 {
     int n_not_auth = 0;
     struct ubifs_scan_node *snod;
     int n_nodes = 0;
     int err;
     u8 hash[UBIFS_HASH_ARR_SZ];
     u8 hmac[UBIFS_HMAC_ARR_SZ];
 
     if (!ubifs_authenticated(c))
         return sleb->nodes_cnt;
 
     list_for_each_entry(snod, &sleb->nodes, list) {
 
         n_nodes++;
 
         if (snod->type == UBIFS_AUTH_NODE) {
             struct ubifs_auth_node *auth = snod->node;
 
             err = authenticate_sleb_hash(c, log_hash, hash);
             if (err)
                 goto out;
 
             err = crypto_shash_tfm_digest(c->hmac_tfm, hash,
                               c->hash_len, hmac);
             if (err)
                 goto out;
 
             err = ubifs_check_hmac(c, auth->hmac, hmac);
             if (err) {
                 err = -EPERM;
                 goto out;
             }
             n_not_auth = 0;
         } else {
             err = crypto_shash_update(log_hash, snod->node,
                           snod->len);
             if (err)
                 goto out;
             n_not_auth++;
         }
     }
 
     /*
      * A powercut can happen when some nodes were written, but not yet
      * the corresponding authentication node. This may only happen on
      * the last bud though.
      */
     if (n_not_auth) {
         if (is_last) {
             dbg_mnt("%d unauthenticated nodes found on LEB %d, Ignoring them",
                 n_not_auth, sleb->lnum);
             err = 0;
         } else {
             dbg_mnt("%d unauthenticated nodes found on non-last LEB %d",
                 n_not_auth, sleb->lnum);
             err = -EPERM;
         }
     } else {
         err = 0;
     }
 out:
     return err ? err : n_nodes - n_not_auth;
 }
 
 /**
  * replay_bud - replay a bud logical eraseblock.
  * @c: UBIFS file-system description object
  * @b: bud entry which describes the bud
  *
  * This function replays bud @bud, recovers it if needed, and adds all nodes
  * from this bud to the replay list. Returns zero in case of success and a
  * negative error code in case of failure.
  */
 static int replay_bud(struct ubifs_info *c, struct bud_entry *b)
 {
     int is_last = is_last_bud(c, b->bud);
     int err = 0, used = 0, lnum = b->bud->lnum, offs = b->bud->start;
     int n_nodes, n = 0;
     struct ubifs_scan_leb *sleb;
     struct ubifs_scan_node *snod;
 
     dbg_mnt("replay bud LEB %d, head %d, offs %d, is_last %d",
         lnum, b->bud->jhead, offs, is_last);
 
     if (c->need_recovery && is_last)
         /*
          * Recover only last LEBs in the journal heads, because power
          * cuts may cause corruptions only in these LEBs, because only
          * these LEBs could possibly be written to at the power cut
          * time.
          */
         sleb = ubifs_recover_leb(c, lnum, offs, c->sbuf, b->bud->jhead);
     else
         sleb = ubifs_scan(c, lnum, offs, c->sbuf, 0);
     if (IS_ERR(sleb))
         return PTR_ERR(sleb);
 
     n_nodes = authenticate_sleb(c, sleb, b->bud->log_hash, is_last);
     if (n_nodes < 0) {
         err = n_nodes;
         goto out;
     }
 
     ubifs_shash_copy_state(c, b->bud->log_hash,
                    c->jheads[b->bud->jhead].log_hash);
 
     /*
      * The bud does not have to start from offset zero - the beginning of
      * the 'lnum' LEB may contain previously committed data. One of the
      * things we have to do in replay is to correctly update lprops with
      * newer information about this LEB.
      *
      * At this point lprops thinks that this LEB has 'c->leb_size - offs'
      * bytes of free space because it only contain information about
      * committed data.
      *
      * But we know that real amount of free space is 'c->leb_size -
      * sleb->endpt', and the space in the 'lnum' LEB between 'offs' and
      * 'sleb->endpt' is used by bud data. We have to correctly calculate
      * how much of these data are dirty and update lprops with this
      * information.
      *
      * The dirt in that LEB region is comprised of padding nodes, deletion
      * nodes, truncation nodes and nodes which are obsoleted by subsequent
      * nodes in this LEB. So instead of calculating clean space, we
      * calculate used space ('used' variable).
      */
 
     list_for_each_entry(snod, &sleb->nodes, list) {
         u8 hash[UBIFS_HASH_ARR_SZ];
         int deletion = 0;
 
         cond_resched();
 
         if (snod->sqnum >= SQNUM_WATERMARK) {
             ubifs_err(c, "file system's life ended");
             goto out_dump;
         }
 
         ubifs_node_calc_hash(c, snod->node, hash);
 
         if (snod->sqnum > c->max_sqnum)
             c->max_sqnum = snod->sqnum;
 
         switch (snod->type) {
         case UBIFS_INO_NODE:
         {
             struct ubifs_ino_node *ino = snod->node;
             loff_t new_size = le64_to_cpu(ino->size);
 
             if (le32_to_cpu(ino->nlink) == 0)
                 deletion = 1;
             err = insert_node(c, lnum, snod->offs, snod->len, hash,
                       &snod->key, snod->sqnum, deletion,
                       &used, 0, new_size);
             break;
         }
         case UBIFS_DATA_NODE:
         {
             struct ubifs_data_node *dn = snod->node;
             loff_t new_size = le32_to_cpu(dn->size) +
                       key_block(c, &snod->key) *
                       UBIFS_BLOCK_SIZE;
 
             err = insert_node(c, lnum, snod->offs, snod->len, hash,
                       &snod->key, snod->sqnum, deletion,
                       &used, 0, new_size);
             break;
         }
         case UBIFS_DENT_NODE:
         case UBIFS_XENT_NODE:
         {
             struct ubifs_dent_node *dent = snod->node;
 
             err = ubifs_validate_entry(c, dent);
             if (err)
                 goto out_dump;
 
             err = insert_dent(c, lnum, snod->offs, snod->len, hash,
                       &snod->key, dent->name,
                       le16_to_cpu(dent->nlen), snod->sqnum,
                       !le64_to_cpu(dent->inum), &used);
             break;
         }
         case UBIFS_TRUN_NODE:
         {
             struct ubifs_trun_node *trun = snod->node;
             loff_t old_size = le64_to_cpu(trun->old_size);
             loff_t new_size = le64_to_cpu(trun->new_size);
             union ubifs_key key;
 
             /* Validate truncation node */
             if (old_size < 0 || old_size > c->max_inode_sz ||
                 new_size < 0 || new_size > c->max_inode_sz ||
                 old_size <= new_size) {
                 ubifs_err(c, "bad truncation node");
                 goto out_dump;
             }
 
             /*
              * Create a fake truncation key just to use the same
              * functions which expect nodes to have keys.
              */
             trun_key_init(c, &key, le32_to_cpu(trun->inum));
             err = insert_node(c, lnum, snod->offs, snod->len, hash,
                       &key, snod->sqnum, 1, &used,
                       old_size, new_size);
             break;
         }
         case UBIFS_AUTH_NODE:
             break;
         default:
             ubifs_err(c, "unexpected node type %d in bud LEB %d:%d",
                   snod->type, lnum, snod->offs);
             err = -EINVAL;
             goto out_dump;
         }
         if (err)
             goto out;
 
         n++;
         if (n == n_nodes)
             break;
     }
 
     ubifs_assert(c, ubifs_search_bud(c, lnum));
     ubifs_assert(c, sleb->endpt - offs >= used);
     ubifs_assert(c, sleb->endpt % c->min_io_size == 0);
 
     b->dirty = sleb->endpt - offs - used;
     b->free = c->leb_size - sleb->endpt;
     dbg_mnt("bud LEB %d replied: dirty %d, free %d",
         lnum, b->dirty, b->free);
 
 out:
     ubifs_scan_destroy(sleb);
     return err;
 
 out_dump:
     ubifs_err(c, "bad node is at LEB %d:%d", lnum, snod->offs);
     ubifs_dump_node(c, snod->node, c->leb_size - snod->offs);
     ubifs_scan_destroy(sleb);
     return -EINVAL;
 }
 
 /**
  * replay_buds - replay all buds.
  * @c: UBIFS file-system description object
  *
  * This function returns zero in case of success and a negative error code in
  * case of failure.
  */
 static int replay_buds(struct ubifs_info *c)
 {
     struct bud_entry *b;
     int err;
     unsigned long long prev_sqnum = 0;
 
     list_for_each_entry(b, &c->replay_buds, list) {
         err = replay_bud(c, b);
         if (err)
             return err;
 
         ubifs_assert(c, b->sqnum > prev_sqnum);
         prev_sqnum = b->sqnum;
     }
 
     return 0;
 }
 
 /**
  * destroy_bud_list - destroy the list of buds to replay.
  * @c: UBIFS file-system description object
  */
 static void destroy_bud_list(struct ubifs_info *c)
 {
     struct bud_entry *b;
 
     while (!list_empty(&c->replay_buds)) {
         b = list_entry(c->replay_buds.next, struct bud_entry, list);
         list_del(&b->list);
         kfree(b);
     }
 }
 
 /**
  * add_replay_bud - add a bud to the list of buds to replay.
  * @c: UBIFS file-system description object
  * @lnum: bud logical eraseblock number to replay
  * @offs: bud start offset
  * @jhead: journal head to which this bud belongs
  * @sqnum: reference node sequence number
  *
  * This function returns zero in case of success and a negative error code in
  * case of failure.
  */
 static int add_replay_bud(struct ubifs_info *c, int lnum, int offs, int jhead,
               unsigned long long sqnum)
 {
     struct ubifs_bud *bud;
     struct bud_entry *b;
     int err;
 
     dbg_mnt("add replay bud LEB %d:%d, head %d", lnum, offs, jhead);
 
     bud = kmalloc(sizeof(struct ubifs_bud), GFP_KERNEL);
     if (!bud)
         return -ENOMEM;
 
     b = kmalloc(sizeof(struct bud_entry), GFP_KERNEL);
     if (!b) {
         err = -ENOMEM;
         goto out;
     }
 
     bud->lnum = lnum;
     bud->start = offs;
     bud->jhead = jhead;
     bud->log_hash = ubifs_hash_get_desc(c);
     if (IS_ERR(bud->log_hash)) {
         err = PTR_ERR(bud->log_hash);
         goto out;
     }
 
     ubifs_shash_copy_state(c, c->log_hash, bud->log_hash);
 
     ubifs_add_bud(c, bud);
 
     b->bud = bud;
     b->sqnum = sqnum;
     list_add_tail(&b->list, &c->replay_buds);
 
     return 0;
 out:
     kfree(bud);
     kfree(b);
 
     return err;
 }
 
 /**
  * validate_ref - validate a reference node.
  * @c: UBIFS file-system description object
  * @ref: the reference node to validate
  *
  * This function returns %1 if a bud reference already exists for the LEB. %0 is
  * returned if the reference node is new, otherwise %-EINVAL is returned if
  * validation failed.
  */
 static int validate_ref(struct ubifs_info *c, const struct ubifs_ref_node *ref)
 {
     struct ubifs_bud *bud;
     int lnum = le32_to_cpu(ref->lnum);
     unsigned int offs = le32_to_cpu(ref->offs);
     unsigned int jhead = le32_to_cpu(ref->jhead);
 
     /*
      * ref->offs may point to the end of LEB when the journal head points
      * to the end of LEB and we write reference node for it during commit.
      * So this is why we require 'offs > c->leb_size'.
      */
     if (jhead >= c->jhead_cnt || lnum >= c->leb_cnt ||
         lnum < c->main_first || offs > c->leb_size ||
         offs & (c->min_io_size - 1))
         return -EINVAL;
 
     /* Make sure we have not already looked at this bud */
     bud = ubifs_search_bud(c, lnum);
     if (bud) {
         if (bud->jhead == jhead && bud->start <= offs)
             return 1;
         ubifs_err(c, "bud at LEB %d:%d was already referred", lnum, offs);
         return -EINVAL;
     }
 
     return 0;
 }
 
 /**
  * replay_log_leb - replay a log logical eraseblock.
  * @c: UBIFS file-system description object
  * @lnum: log logical eraseblock to replay
  * @offs: offset to start replaying from
  * @sbuf: scan buffer
  *
  * This function replays a log LEB and returns zero in case of success, %1 if
  * this is the last LEB in the log, and a negative error code in case of
  * failure.
  */
 static int replay_log_leb(struct ubifs_info *c, int lnum, int offs, void *sbuf)
 {
     int err;
     struct ubifs_scan_leb *sleb;
     struct ubifs_scan_node *snod;
     const struct ubifs_cs_node *node;
 
     dbg_mnt("replay log LEB %d:%d", lnum, offs);
     sleb = ubifs_scan(c, lnum, offs, sbuf, c->need_recovery);
     if (IS_ERR(sleb)) {
         if (PTR_ERR(sleb) != -EUCLEAN || !c->need_recovery)
             return PTR_ERR(sleb);
         /*
          * Note, the below function will recover this log LEB only if
          * it is the last, because unclean reboots can possibly corrupt
          * only the tail of the log.
          */
         sleb = ubifs_recover_log_leb(c, lnum, offs, sbuf);
         if (IS_ERR(sleb))
             return PTR_ERR(sleb);
     }
 
     if (sleb->nodes_cnt == 0) {
         err = 1;
         goto out;
     }
 
     node = sleb->buf;
     snod = list_entry(sleb->nodes.next, struct ubifs_scan_node, list);
     if (c->cs_sqnum == 0) {
         /*
          * This is the first log LEB we are looking at, make sure that
          * the first node is a commit start node. Also record its
          * sequence number so that UBIFS can determine where the log
          * ends, because all nodes which were have higher sequence
          * numbers.
          */
         if (snod->type != UBIFS_CS_NODE) {
             ubifs_err(c, "first log node at LEB %d:%d is not CS node",
                   lnum, offs);
             goto out_dump;
         }
         if (le64_to_cpu(node->cmt_no) != c->cmt_no) {
             ubifs_err(c, "first CS node at LEB %d:%d has wrong commit number %llu expected %llu",
                   lnum, offs,
                   (unsigned long long)le64_to_cpu(node->cmt_no),
                   c->cmt_no);
             goto out_dump;
         }
 
         c->cs_sqnum = le64_to_cpu(node->ch.sqnum);
         dbg_mnt("commit start sqnum %llu", c->cs_sqnum);
 
         err = ubifs_shash_init(c, c->log_hash);
         if (err)
             goto out;
 
         err = ubifs_shash_update(c, c->log_hash, node, UBIFS_CS_NODE_SZ);
         if (err < 0)
             goto out;
     }
 
     if (snod->sqnum < c->cs_sqnum) {
         /*
          * This means that we reached end of log and now
          * look to the older log data, which was already
          * committed but the eraseblock was not erased (UBIFS
          * only un-maps it). So this basically means we have to
          * exit with "end of log" code.
          */
         err = 1;
         goto out;
     }
 
     /* Make sure the first node sits at offset zero of the LEB */
     if (snod->offs != 0) {
         ubifs_err(c, "first node is not at zero offset");
         goto out_dump;
     }
 
     list_for_each_entry(snod, &sleb->nodes, list) {
         cond_resched();
 
         if (snod->sqnum >= SQNUM_WATERMARK) {
             ubifs_err(c, "file system's life ended");
             goto out_dump;
         }
 
         if (snod->sqnum < c->cs_sqnum) {
             ubifs_err(c, "bad sqnum %llu, commit sqnum %llu",
                   snod->sqnum, c->cs_sqnum);
             goto out_dump;
         }
 
         if (snod->sqnum > c->max_sqnum)
             c->max_sqnum = snod->sqnum;
 
         switch (snod->type) {
         case UBIFS_REF_NODE: {
             const struct ubifs_ref_node *ref = snod->node;
 
             err = validate_ref(c, ref);
             if (err == 1)
                 break; /* Already have this bud */
             if (err)
                 goto out_dump;
 
             err = ubifs_shash_update(c, c->log_hash, ref,
                          UBIFS_REF_NODE_SZ);
             if (err)
                 goto out;
 
             err = add_replay_bud(c, le32_to_cpu(ref->lnum),
                          le32_to_cpu(ref->offs),
                          le32_to_cpu(ref->jhead),
                          snod->sqnum);
             if (err)
                 goto out;
 
             break;
         }
         case UBIFS_CS_NODE:
             /* Make sure it sits at the beginning of LEB */
             if (snod->offs != 0) {
                 ubifs_err(c, "unexpected node in log");
                 goto out_dump;
             }
             break;
         default:
             ubifs_err(c, "unexpected node in log");
             goto out_dump;
         }
     }
 
     if (sleb->endpt || c->lhead_offs >= c->leb_size) {
         c->lhead_lnum = lnum;
         c->lhead_offs = sleb->endpt;
     }
 
     err = !sleb->endpt;
 out:
     ubifs_scan_destroy(sleb);
     return err;
 
 out_dump:
     ubifs_err(c, "log error detected while replaying the log at LEB %d:%d",
           lnum, offs + snod->offs);
     ubifs_dump_node(c, snod->node, c->leb_size - snod->offs);
     ubifs_scan_destroy(sleb);
     return -EINVAL;
 }
 
 /**
  * take_ihead - update the status of the index head in lprops to 'taken'.
  * @c: UBIFS file-system description object
  *
  * This function returns the amount of free space in the index head LEB or a
  * negative error code.
  */
 static int take_ihead(struct ubifs_info *c)
 {
     const struct ubifs_lprops *lp;
     int err, free;
 
     ubifs_get_lprops(c);
 
     lp = ubifs_lpt_lookup_dirty(c, c->ihead_lnum);
     if (IS_ERR(lp)) {
         err = PTR_ERR(lp);
         goto out;
     }
 
     free = lp->free;
 
     lp = ubifs_change_lp(c, lp, LPROPS_NC, LPROPS_NC,
                  lp->flags | LPROPS_TAKEN, 0);
     if (IS_ERR(lp)) {
         err = PTR_ERR(lp);
         goto out;
     }
 
     err = free;
 out:
     ubifs_release_lprops(c);
     return err;
 }
 
 /**
  * ubifs_replay_journal - replay journal.
  * @c: UBIFS file-system description object
  *
  * This function scans the journal, replays and cleans it up. It makes sure all
  * memory data structures related to uncommitted journal are built (dirty TNC
  * tree, tree of buds, modified lprops, etc).
  */
 int ubifs_replay_journal(struct ubifs_info *c)
 {
     int err, lnum, free;
 
     BUILD_BUG_ON(UBIFS_TRUN_KEY > 5);
 
     /* Update the status of the index head in lprops to 'taken' */
     free = take_ihead(c);
     if (free < 0)
         return free; /* Error code */
 
     if (c->ihead_offs != c->leb_size - free) {
         ubifs_err(c, "bad index head LEB %d:%d", c->ihead_lnum,
               c->ihead_offs);
         return -EINVAL;
     }
 
     dbg_mnt("start replaying the journal");
     c->replaying = 1;
     lnum = c->ltail_lnum = c->lhead_lnum;
 
     do {
         err = replay_log_leb(c, lnum, 0, c->sbuf);
         if (err == 1) {
             if (lnum != c->lhead_lnum)
                 /* We hit the end of the log */
                 break;
 
             /*
              * The head of the log must always start with the
              * "commit start" node on a properly formatted UBIFS.
              * But we found no nodes at all, which means that
              * something went wrong and we cannot proceed mounting
              * the file-system.
              */
             ubifs_err(c, "no UBIFS nodes found at the log head LEB %d:%d, possibly corrupted",
                   lnum, 0);
             err = -EINVAL;
         }
         if (err)
             goto out;
         lnum = ubifs_next_log_lnum(c, lnum);
     } while (lnum != c->ltail_lnum);
 
     err = replay_buds(c);
     if (err)
         goto out;
 
     err = apply_replay_list(c);
     if (err)
         goto out;
 
     err = set_buds_lprops(c);
     if (err)
         goto out;
 
     /*
      * UBIFS budgeting calculations use @c->bi.uncommitted_idx variable
      * to roughly estimate index growth. Things like @c->bi.min_idx_lebs
      * depend on it. This means we have to initialize it to make sure
      * budgeting works properly.
      */
     c->bi.uncommitted_idx = atomic_long_read(&c->dirty_zn_cnt);
     c->bi.uncommitted_idx *= c->max_idx_node_sz;
 
     ubifs_assert(c, c->bud_bytes <= c->max_bud_bytes || c->need_recovery);
     dbg_mnt("finished, log head LEB %d:%d, max_sqnum %llu, highest_inum %lu",
         c->lhead_lnum, c->lhead_offs, c->max_sqnum,
         (unsigned long)c->highest_inum);
 out:
     destroy_replay_list(c);
     destroy_bud_list(c);
     c->replaying = 0;
     return err;
 }

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