477 lines
12 KiB
C
477 lines
12 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* This file is part of UBIFS.
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*
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* Copyright (C) 2006-2008 Nokia Corporation.
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*
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* Authors: Artem Bityutskiy (Битюцкий Артём)
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* Adrian Hunter
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*/
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/* This file implements reading and writing the master node */
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#include "ubifs.h"
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/**
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* ubifs_compare_master_node - compare two UBIFS master nodes
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* @c: UBIFS file-system description object
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* @m1: the first node
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* @m2: the second node
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*
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* This function compares two UBIFS master nodes. Returns 0 if they are equal
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* and nonzero if not.
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*/
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int ubifs_compare_master_node(struct ubifs_info *c, void *m1, void *m2)
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{
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int ret;
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int behind;
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int hmac_offs = offsetof(struct ubifs_mst_node, hmac);
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/*
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* Do not compare the common node header since the sequence number and
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* hence the CRC are different.
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*/
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ret = memcmp(m1 + UBIFS_CH_SZ, m2 + UBIFS_CH_SZ,
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hmac_offs - UBIFS_CH_SZ);
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if (ret)
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return ret;
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/*
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* Do not compare the embedded HMAC aswell which also must be different
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* due to the different common node header.
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*/
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behind = hmac_offs + UBIFS_MAX_HMAC_LEN;
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if (UBIFS_MST_NODE_SZ > behind)
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return memcmp(m1 + behind, m2 + behind, UBIFS_MST_NODE_SZ - behind);
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return 0;
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}
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/* mst_node_check_hash - Check hash of a master node
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* @c: UBIFS file-system description object
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* @mst: The master node
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* @expected: The expected hash of the master node
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*
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* This checks the hash of a master node against a given expected hash.
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* Note that we have two master nodes on a UBIFS image which have different
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* sequence numbers and consequently different CRCs. To be able to match
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* both master nodes we exclude the common node header containing the sequence
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* number and CRC from the hash.
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*
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* Returns 0 if the hashes are equal, a negative error code otherwise.
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*/
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static int mst_node_check_hash(const struct ubifs_info *c,
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const struct ubifs_mst_node *mst,
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const u8 *expected)
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{
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u8 calc[UBIFS_MAX_HASH_LEN];
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const void *node = mst;
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SHASH_DESC_ON_STACK(shash, c->hash_tfm);
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shash->tfm = c->hash_tfm;
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crypto_shash_digest(shash, node + sizeof(struct ubifs_ch),
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UBIFS_MST_NODE_SZ - sizeof(struct ubifs_ch), calc);
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if (ubifs_check_hash(c, expected, calc))
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return -EPERM;
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return 0;
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}
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/**
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* scan_for_master - search the valid master node.
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* @c: UBIFS file-system description object
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*
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* This function scans the master node LEBs and search for the latest master
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* node. Returns zero in case of success, %-EUCLEAN if there master area is
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* corrupted and requires recovery, and a negative error code in case of
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* failure.
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*/
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static int scan_for_master(struct ubifs_info *c)
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{
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struct ubifs_scan_leb *sleb;
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struct ubifs_scan_node *snod;
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int lnum, offs = 0, nodes_cnt, err;
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lnum = UBIFS_MST_LNUM;
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sleb = ubifs_scan(c, lnum, 0, c->sbuf, 1);
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if (IS_ERR(sleb))
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return PTR_ERR(sleb);
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nodes_cnt = sleb->nodes_cnt;
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if (nodes_cnt > 0) {
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snod = list_entry(sleb->nodes.prev, struct ubifs_scan_node,
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list);
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if (snod->type != UBIFS_MST_NODE)
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goto out_dump;
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memcpy(c->mst_node, snod->node, snod->len);
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offs = snod->offs;
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}
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ubifs_scan_destroy(sleb);
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lnum += 1;
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sleb = ubifs_scan(c, lnum, 0, c->sbuf, 1);
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if (IS_ERR(sleb))
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return PTR_ERR(sleb);
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if (sleb->nodes_cnt != nodes_cnt)
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goto out;
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if (!sleb->nodes_cnt)
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goto out;
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snod = list_entry(sleb->nodes.prev, struct ubifs_scan_node, list);
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if (snod->type != UBIFS_MST_NODE)
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goto out_dump;
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if (snod->offs != offs)
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goto out;
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if (ubifs_compare_master_node(c, c->mst_node, snod->node))
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goto out;
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c->mst_offs = offs;
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ubifs_scan_destroy(sleb);
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if (!ubifs_authenticated(c))
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return 0;
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if (ubifs_hmac_zero(c, c->mst_node->hmac)) {
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err = mst_node_check_hash(c, c->mst_node,
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c->sup_node->hash_mst);
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if (err)
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ubifs_err(c, "Failed to verify master node hash");
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} else {
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err = ubifs_node_verify_hmac(c, c->mst_node,
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sizeof(struct ubifs_mst_node),
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offsetof(struct ubifs_mst_node, hmac));
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if (err)
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ubifs_err(c, "Failed to verify master node HMAC");
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}
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if (err)
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return -EPERM;
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return 0;
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out:
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ubifs_scan_destroy(sleb);
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return -EUCLEAN;
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out_dump:
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ubifs_err(c, "unexpected node type %d master LEB %d:%d",
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snod->type, lnum, snod->offs);
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ubifs_scan_destroy(sleb);
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return -EINVAL;
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}
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/**
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* validate_master - validate master node.
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* @c: UBIFS file-system description object
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*
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* This function validates data which was read from master node. Returns zero
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* if the data is all right and %-EINVAL if not.
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*/
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static int validate_master(const struct ubifs_info *c)
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{
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long long main_sz;
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int err;
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if (c->max_sqnum >= SQNUM_WATERMARK) {
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err = 1;
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goto out;
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}
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if (c->cmt_no >= c->max_sqnum) {
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err = 2;
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goto out;
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}
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if (c->highest_inum >= INUM_WATERMARK) {
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err = 3;
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goto out;
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}
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if (c->lhead_lnum < UBIFS_LOG_LNUM ||
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c->lhead_lnum >= UBIFS_LOG_LNUM + c->log_lebs ||
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c->lhead_offs < 0 || c->lhead_offs >= c->leb_size ||
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c->lhead_offs & (c->min_io_size - 1)) {
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err = 4;
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goto out;
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}
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if (c->zroot.lnum >= c->leb_cnt || c->zroot.lnum < c->main_first ||
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c->zroot.offs >= c->leb_size || c->zroot.offs & 7) {
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err = 5;
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goto out;
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}
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if (c->zroot.len < c->ranges[UBIFS_IDX_NODE].min_len ||
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c->zroot.len > c->ranges[UBIFS_IDX_NODE].max_len) {
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err = 6;
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goto out;
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}
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if (c->gc_lnum >= c->leb_cnt || c->gc_lnum < c->main_first) {
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err = 7;
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goto out;
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}
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if (c->ihead_lnum >= c->leb_cnt || c->ihead_lnum < c->main_first ||
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c->ihead_offs % c->min_io_size || c->ihead_offs < 0 ||
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c->ihead_offs > c->leb_size || c->ihead_offs & 7) {
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err = 8;
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goto out;
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}
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main_sz = (long long)c->main_lebs * c->leb_size;
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if (c->bi.old_idx_sz & 7 || c->bi.old_idx_sz >= main_sz) {
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err = 9;
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goto out;
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}
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if (c->lpt_lnum < c->lpt_first || c->lpt_lnum > c->lpt_last ||
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c->lpt_offs < 0 || c->lpt_offs + c->nnode_sz > c->leb_size) {
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err = 10;
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goto out;
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}
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if (c->nhead_lnum < c->lpt_first || c->nhead_lnum > c->lpt_last ||
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c->nhead_offs < 0 || c->nhead_offs % c->min_io_size ||
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c->nhead_offs > c->leb_size) {
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err = 11;
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goto out;
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}
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if (c->ltab_lnum < c->lpt_first || c->ltab_lnum > c->lpt_last ||
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c->ltab_offs < 0 ||
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c->ltab_offs + c->ltab_sz > c->leb_size) {
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err = 12;
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goto out;
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}
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if (c->big_lpt && (c->lsave_lnum < c->lpt_first ||
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c->lsave_lnum > c->lpt_last || c->lsave_offs < 0 ||
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c->lsave_offs + c->lsave_sz > c->leb_size)) {
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err = 13;
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goto out;
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}
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if (c->lscan_lnum < c->main_first || c->lscan_lnum >= c->leb_cnt) {
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err = 14;
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goto out;
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}
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if (c->lst.empty_lebs < 0 || c->lst.empty_lebs > c->main_lebs - 2) {
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err = 15;
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goto out;
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}
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if (c->lst.idx_lebs < 0 || c->lst.idx_lebs > c->main_lebs - 1) {
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err = 16;
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goto out;
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}
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if (c->lst.total_free < 0 || c->lst.total_free > main_sz ||
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c->lst.total_free & 7) {
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err = 17;
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goto out;
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}
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if (c->lst.total_dirty < 0 || (c->lst.total_dirty & 7)) {
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err = 18;
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goto out;
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}
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if (c->lst.total_used < 0 || (c->lst.total_used & 7)) {
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err = 19;
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goto out;
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}
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if (c->lst.total_free + c->lst.total_dirty +
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c->lst.total_used > main_sz) {
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err = 20;
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goto out;
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}
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if (c->lst.total_dead + c->lst.total_dark +
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c->lst.total_used + c->bi.old_idx_sz > main_sz) {
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err = 21;
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goto out;
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}
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if (c->lst.total_dead < 0 ||
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c->lst.total_dead > c->lst.total_free + c->lst.total_dirty ||
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c->lst.total_dead & 7) {
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err = 22;
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goto out;
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}
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if (c->lst.total_dark < 0 ||
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c->lst.total_dark > c->lst.total_free + c->lst.total_dirty ||
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c->lst.total_dark & 7) {
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err = 23;
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goto out;
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}
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return 0;
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out:
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ubifs_err(c, "bad master node at offset %d error %d", c->mst_offs, err);
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ubifs_dump_node(c, c->mst_node);
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return -EINVAL;
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}
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/**
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* ubifs_read_master - read master node.
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* @c: UBIFS file-system description object
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*
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* This function finds and reads the master node during file-system mount. If
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* the flash is empty, it creates default master node as well. Returns zero in
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* case of success and a negative error code in case of failure.
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*/
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int ubifs_read_master(struct ubifs_info *c)
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{
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int err, old_leb_cnt;
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c->mst_node = kzalloc(c->mst_node_alsz, GFP_KERNEL);
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if (!c->mst_node)
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return -ENOMEM;
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err = scan_for_master(c);
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if (err) {
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if (err == -EUCLEAN)
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err = ubifs_recover_master_node(c);
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if (err)
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/*
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* Note, we do not free 'c->mst_node' here because the
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* unmount routine will take care of this.
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*/
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return err;
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}
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/* Make sure that the recovery flag is clear */
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c->mst_node->flags &= cpu_to_le32(~UBIFS_MST_RCVRY);
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c->max_sqnum = le64_to_cpu(c->mst_node->ch.sqnum);
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c->highest_inum = le64_to_cpu(c->mst_node->highest_inum);
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c->cmt_no = le64_to_cpu(c->mst_node->cmt_no);
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c->zroot.lnum = le32_to_cpu(c->mst_node->root_lnum);
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c->zroot.offs = le32_to_cpu(c->mst_node->root_offs);
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c->zroot.len = le32_to_cpu(c->mst_node->root_len);
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c->lhead_lnum = le32_to_cpu(c->mst_node->log_lnum);
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c->gc_lnum = le32_to_cpu(c->mst_node->gc_lnum);
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c->ihead_lnum = le32_to_cpu(c->mst_node->ihead_lnum);
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c->ihead_offs = le32_to_cpu(c->mst_node->ihead_offs);
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c->bi.old_idx_sz = le64_to_cpu(c->mst_node->index_size);
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c->lpt_lnum = le32_to_cpu(c->mst_node->lpt_lnum);
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c->lpt_offs = le32_to_cpu(c->mst_node->lpt_offs);
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c->nhead_lnum = le32_to_cpu(c->mst_node->nhead_lnum);
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c->nhead_offs = le32_to_cpu(c->mst_node->nhead_offs);
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c->ltab_lnum = le32_to_cpu(c->mst_node->ltab_lnum);
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c->ltab_offs = le32_to_cpu(c->mst_node->ltab_offs);
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c->lsave_lnum = le32_to_cpu(c->mst_node->lsave_lnum);
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c->lsave_offs = le32_to_cpu(c->mst_node->lsave_offs);
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c->lscan_lnum = le32_to_cpu(c->mst_node->lscan_lnum);
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c->lst.empty_lebs = le32_to_cpu(c->mst_node->empty_lebs);
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c->lst.idx_lebs = le32_to_cpu(c->mst_node->idx_lebs);
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old_leb_cnt = le32_to_cpu(c->mst_node->leb_cnt);
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c->lst.total_free = le64_to_cpu(c->mst_node->total_free);
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c->lst.total_dirty = le64_to_cpu(c->mst_node->total_dirty);
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c->lst.total_used = le64_to_cpu(c->mst_node->total_used);
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c->lst.total_dead = le64_to_cpu(c->mst_node->total_dead);
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c->lst.total_dark = le64_to_cpu(c->mst_node->total_dark);
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ubifs_copy_hash(c, c->mst_node->hash_root_idx, c->zroot.hash);
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c->calc_idx_sz = c->bi.old_idx_sz;
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if (c->mst_node->flags & cpu_to_le32(UBIFS_MST_NO_ORPHS))
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c->no_orphs = 1;
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if (old_leb_cnt != c->leb_cnt) {
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/* The file system has been resized */
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int growth = c->leb_cnt - old_leb_cnt;
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if (c->leb_cnt < old_leb_cnt ||
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c->leb_cnt < UBIFS_MIN_LEB_CNT) {
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ubifs_err(c, "bad leb_cnt on master node");
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ubifs_dump_node(c, c->mst_node);
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return -EINVAL;
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}
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dbg_mnt("Auto resizing (master) from %d LEBs to %d LEBs",
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old_leb_cnt, c->leb_cnt);
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c->lst.empty_lebs += growth;
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c->lst.total_free += growth * (long long)c->leb_size;
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c->lst.total_dark += growth * (long long)c->dark_wm;
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/*
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* Reflect changes back onto the master node. N.B. the master
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* node gets written immediately whenever mounting (or
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* remounting) in read-write mode, so we do not need to write it
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* here.
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*/
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c->mst_node->leb_cnt = cpu_to_le32(c->leb_cnt);
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c->mst_node->empty_lebs = cpu_to_le32(c->lst.empty_lebs);
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c->mst_node->total_free = cpu_to_le64(c->lst.total_free);
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c->mst_node->total_dark = cpu_to_le64(c->lst.total_dark);
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}
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err = validate_master(c);
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if (err)
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return err;
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err = dbg_old_index_check_init(c, &c->zroot);
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return err;
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}
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/**
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* ubifs_write_master - write master node.
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* @c: UBIFS file-system description object
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*
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* This function writes the master node. Returns zero in case of success and a
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* negative error code in case of failure. The master node is written twice to
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* enable recovery.
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*/
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int ubifs_write_master(struct ubifs_info *c)
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{
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int err, lnum, offs, len;
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ubifs_assert(c, !c->ro_media && !c->ro_mount);
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if (c->ro_error)
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return -EROFS;
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lnum = UBIFS_MST_LNUM;
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offs = c->mst_offs + c->mst_node_alsz;
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len = UBIFS_MST_NODE_SZ;
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if (offs + UBIFS_MST_NODE_SZ > c->leb_size) {
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err = ubifs_leb_unmap(c, lnum);
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if (err)
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return err;
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offs = 0;
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}
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c->mst_offs = offs;
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c->mst_node->highest_inum = cpu_to_le64(c->highest_inum);
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ubifs_copy_hash(c, c->zroot.hash, c->mst_node->hash_root_idx);
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err = ubifs_write_node_hmac(c, c->mst_node, len, lnum, offs,
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offsetof(struct ubifs_mst_node, hmac));
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if (err)
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return err;
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lnum += 1;
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|
|
if (offs == 0) {
|
|
err = ubifs_leb_unmap(c, lnum);
|
|
if (err)
|
|
return err;
|
|
}
|
|
err = ubifs_write_node_hmac(c, c->mst_node, len, lnum, offs,
|
|
offsetof(struct ubifs_mst_node, hmac));
|
|
|
|
return err;
|
|
}
|