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![Artem Bityutskiy](/assets/img/avatar_default.png)
The R/O state may have various reasons: 1. The UBI volume is R/O 2. The FS is mounted R/O 3. The FS switched to R/O mode because of an error However, in UBIFS we have only one variable which represents cases 1 and 3 - 'c->ro_media'. Indeed, we set this to 1 if we switch to R/O mode due to an error, and then we test it in many places to make sure that we stop writing as soon as the error happens. But this is very unclean. One consequence of this, for example, is that in 'ubifs_remount_fs()' we use 'c->ro_media' to check whether we are in R/O mode because on an error, and we print a message in this case. However, if we are in R/O mode because the media is R/O, our message is bogus. This patch introduces new flag - 'c->ro_error' which is set when we switch to R/O mode because of an error. It also changes all "if (c->ro_media)" checks to "if (c->ro_error)" checks, because this is what the checks actually mean. We do not need to check for 'c->ro_media' because if the UBI volume is in R/O mode, we do not allow R/W mounting, and now writes can happen. This is guaranteed by VFS. But it is good to double-check this, so this patch also adds many "ubifs_assert(!c->ro_media)" checks. In the 'ubifs_remount_fs()' function this patch makes a bit more changes - it fixes the error messages as well. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
396 lines
10 KiB
C
396 lines
10 KiB
C
/*
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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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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published by
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* the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program; if not, write to the Free Software Foundation, Inc., 51
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* Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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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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* 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;
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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 (memcmp((void *)c->mst_node + UBIFS_CH_SZ,
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(void *)snod->node + UBIFS_CH_SZ,
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UBIFS_MST_NODE_SZ - UBIFS_CH_SZ))
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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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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("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->old_idx_sz & 7 || c->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->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("bad master node at offset %d error %d", c->mst_offs, err);
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dbg_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->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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c->calc_idx_sz = c->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("bad leb_cnt on master node");
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dbg_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. The caller has to take the
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* @c->mst_mutex lock before calling this function. Returns zero in case of
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* success and a negative error code in case of failure. The master node is
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* written twice to 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->ro_media);
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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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err = ubifs_write_node(c, c->mst_node, len, lnum, offs, UBI_SHORTTERM);
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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) {
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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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}
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err = ubifs_write_node(c, c->mst_node, len, lnum, offs, UBI_SHORTTERM);
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return err;
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}
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