- 根目录:
- fs
- ubifs
- master.c
/*
* This file is part of UBIFS.
*
* Copyright (C) 2006-2008 Nokia Corporation.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published by
* the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc., 51
* Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
* Authors: Artem Bityutskiy (Битюцкий Артём)
* Adrian Hunter
*/
/* This file implements reading and writing the master node */
#include "ubifs.h"
/**
* scan_for_master - search the valid master node.
* @c: UBIFS file-system description object
*
* This function scans the master node LEBs and search for the latest master
* node. Returns zero in case of success, %-EUCLEAN if there master area is
* corrupted and requires recovery, and a negative error code in case of
* failure.
*/
static int scan_for_master(struct ubifs_info *c)
{
struct ubifs_scan_leb *sleb;
struct ubifs_scan_node *snod;
int lnum, offs = 0, nodes_cnt;
lnum = UBIFS_MST_LNUM;
sleb = ubifs_scan(c, lnum, 0, c->sbuf, 1);
if (IS_ERR(sleb))
return PTR_ERR(sleb);
nodes_cnt = sleb->nodes_cnt;
if (nodes_cnt > 0) {
snod = list_entry(sleb->nodes.prev, struct ubifs_scan_node,
list);
if (snod->type != UBIFS_MST_NODE)
goto out_dump;
memcpy(c->mst_node, snod->node, snod->len);
offs = snod->offs;
}
ubifs_scan_destroy(sleb);
lnum += 1;
sleb = ubifs_scan(c, lnum, 0, c->sbuf, 1);
if (IS_ERR(sleb))
return PTR_ERR(sleb);
if (sleb->nodes_cnt != nodes_cnt)
goto out;
if (!sleb->nodes_cnt)
goto out;
snod = list_entry(sleb->nodes.prev, struct ubifs_scan_node, list);
if (snod->type != UBIFS_MST_NODE)
goto out_dump;
if (snod->offs != offs)
goto out;
if (memcmp((void *)c->mst_node + UBIFS_CH_SZ,
(void *)snod->node + UBIFS_CH_SZ,
UBIFS_MST_NODE_SZ - UBIFS_CH_SZ))
goto out;
c->mst_offs = offs;
ubifs_scan_destroy(sleb);
return 0;
out:
ubifs_scan_destroy(sleb);
return -EUCLEAN;
out_dump:
ubifs_err(c, "unexpected node type %d master LEB %d:%d",
snod->type, lnum, snod->offs);
ubifs_scan_destroy(sleb);
return -EINVAL;
}
/**
* validate_master - validate master node.
* @c: UBIFS file-system description object
*
* This function validates data which was read from master node. Returns zero
* if the data is all right and %-EINVAL if not.
*/
static int validate_master(const struct ubifs_info *c)
{
long long main_sz;
int err;
if (c->max_sqnum >= SQNUM_WATERMARK) {
err = 1;
goto out;
}
if (c->cmt_no >= c->max_sqnum) {
err = 2;
goto out;
}
if (c->highest_inum >= INUM_WATERMARK) {
err = 3;
goto out;
}
if (c->lhead_lnum < UBIFS_LOG_LNUM ||
c->lhead_lnum >= UBIFS_LOG_LNUM + c->log_lebs ||
c->lhead_offs < 0 || c->lhead_offs >= c->leb_size ||
c->lhead_offs & (c->min_io_size - 1)) {
err = 4;
goto out;
}
if (c->zroot.lnum >= c->leb_cnt || c->zroot.lnum < c->main_first ||
c->zroot.offs >= c->leb_size || c->zroot.offs & 7) {
err = 5;
goto out;
}
if (c->zroot.len < c->ranges[UBIFS_IDX_NODE].min_len ||
c->zroot.len > c->ranges[UBIFS_IDX_NODE].max_len) {
err = 6;
goto out;
}
if (c->gc_lnum >= c->leb_cnt || c->gc_lnum < c->main_first) {
err = 7;
goto out;
}
if (c->ihead_lnum >= c->leb_cnt || c->ihead_lnum < c->main_first ||
c->ihead_offs % c->min_io_size || c->ihead_offs < 0 ||
c->ihead_offs > c->leb_size || c->ihead_offs & 7) {
err = 8;
goto out;
}
main_sz = (long long)c->main_lebs * c->leb_size;
if (c->bi.old_idx_sz & 7 || c->bi.old_idx_sz >= main_sz) {
err = 9;
goto out;
}
if (c->lpt_lnum < c->lpt_first || c->lpt_lnum > c->lpt_last ||
c->lpt_offs < 0 || c->lpt_offs + c->nnode_sz > c->leb_size) {
err = 10;
goto out;
}
if (c->nhead_lnum < c->lpt_first || c->nhead_lnum > c->lpt_last ||
c->nhead_offs < 0 || c->nhead_offs % c->min_io_size ||
c->nhead_offs > c->leb_size) {
err = 11;
goto out;
}
if (c->ltab_lnum < c->lpt_first || c->ltab_lnum > c->lpt_last ||
c->ltab_offs < 0 ||
c->ltab_offs + c->ltab_sz > c->leb_size) {
err = 12;
goto out;
}
if (c->big_lpt && (c->lsave_lnum < c->lpt_first ||
c->lsave_lnum > c->lpt_last || c->lsave_offs < 0 ||
c->lsave_offs + c->lsave_sz > c->leb_size)) {
err = 13;
goto out;
}
if (c->lscan_lnum < c->main_first || c->lscan_lnum >= c->leb_cnt) {
err = 14;
goto out;
}
if (c->lst.empty_lebs < 0 || c->lst.empty_lebs > c->main_lebs - 2) {
err = 15;
goto out;
}
if (c->lst.idx_lebs < 0 || c->lst.idx_lebs > c->main_lebs - 1) {
err = 16;
goto out;
}
if (c->lst.total_free < 0 || c->lst.total_free > main_sz ||
c->lst.total_free & 7) {
err = 17;
goto out;
}
if (c->lst.total_dirty < 0 || (c->lst.total_dirty & 7)) {
err = 18;
goto out;
}
if (c->lst.total_used < 0 || (c->lst.total_used & 7)) {
err = 19;
goto out;
}
if (c->lst.total_free + c->lst.total_dirty +
c->lst.total_used > main_sz) {
err = 20;
goto out;
}
if (c->lst.total_dead + c->lst.total_dark +
c->lst.total_used + c->bi.old_idx_sz > main_sz) {
err = 21;
goto out;
}
if (c->lst.total_dead < 0 ||
c->lst.total_dead > c->lst.total_free + c->lst.total_dirty ||
c->lst.total_dead & 7) {
err = 22;
goto out;
}
if (c->lst.total_dark < 0 ||
c->lst.total_dark > c->lst.total_free + c->lst.total_dirty ||
c->lst.total_dark & 7) {
err = 23;
goto out;
}
return 0;
out:
ubifs_err(c, "bad master node at offset %d error %d", c->mst_offs, err);
ubifs_dump_node(c, c->mst_node);
return -EINVAL;
}
/**
* ubifs_read_master - read master node.
* @c: UBIFS file-system description object
*
* This function finds and reads the master node during file-system mount. If
* the flash is empty, it creates default master node as well. Returns zero in
* case of success and a negative error code in case of failure.
*/
int ubifs_read_master(struct ubifs_info *c)
{
int err, old_leb_cnt;
c->mst_node = kzalloc(c->mst_node_alsz, GFP_KERNEL);
if (!c->mst_node)
return -ENOMEM;
err = scan_for_master(c);
if (err) {
if (err == -EUCLEAN)
err = ubifs_recover_master_node(c);
if (err)
/*
* Note, we do not free 'c->mst_node' here because the
* unmount routine will take care of this.
*/
return err;
}
/* Make sure that the recovery flag is clear */
c->mst_node->flags &= cpu_to_le32(~UBIFS_MST_RCVRY);
c->max_sqnum = le64_to_cpu(c->mst_node->ch.sqnum);
c->highest_inum = le64_to_cpu(c->mst_node->highest_inum);
c->cmt_no = le64_to_cpu(c->mst_node->cmt_no);
c->zroot.lnum = le32_to_cpu(c->mst_node->root_lnum);
c->zroot.offs = le32_to_cpu(c->mst_node->root_offs);
c->zroot.len = le32_to_cpu(c->mst_node->root_len);
c->lhead_lnum = le32_to_cpu(c->mst_node->log_lnum);
c->gc_lnum = le32_to_cpu(c->mst_node->gc_lnum);
c->ihead_lnum = le32_to_cpu(c->mst_node->ihead_lnum);
c->ihead_offs = le32_to_cpu(c->mst_node->ihead_offs);
c->bi.old_idx_sz = le64_to_cpu(c->mst_node->index_size);
c->lpt_lnum = le32_to_cpu(c->mst_node->lpt_lnum);
c->lpt_offs = le32_to_cpu(c->mst_node->lpt_offs);
c->nhead_lnum = le32_to_cpu(c->mst_node->nhead_lnum);
c->nhead_offs = le32_to_cpu(c->mst_node->nhead_offs);
c->ltab_lnum = le32_to_cpu(c->mst_node->ltab_lnum);
c->ltab_offs = le32_to_cpu(c->mst_node->ltab_offs);
c->lsave_lnum = le32_to_cpu(c->mst_node->lsave_lnum);
c->lsave_offs = le32_to_cpu(c->mst_node->lsave_offs);
c->lscan_lnum = le32_to_cpu(c->mst_node->lscan_lnum);
c->lst.empty_lebs = le32_to_cpu(c->mst_node->empty_lebs);
c->lst.idx_lebs = le32_to_cpu(c->mst_node->idx_lebs);
old_leb_cnt = le32_to_cpu(c->mst_node->leb_cnt);
c->lst.total_free = le64_to_cpu(c->mst_node->total_free);
c->lst.total_dirty = le64_to_cpu(c->mst_node->total_dirty);
c->lst.total_used = le64_to_cpu(c->mst_node->total_used);
c->lst.total_dead = le64_to_cpu(c->mst_node->total_dead);
c->lst.total_dark = le64_to_cpu(c->mst_node->total_dark);
c->calc_idx_sz = c->bi.old_idx_sz;
if (c->mst_node->flags & cpu_to_le32(UBIFS_MST_NO_ORPHS))
c->no_orphs = 1;
if (old_leb_cnt != c->leb_cnt) {
/* The file system has been resized */
int growth = c->leb_cnt - old_leb_cnt;
if (c->leb_cnt < old_leb_cnt ||
c->leb_cnt < UBIFS_MIN_LEB_CNT) {
ubifs_err(c, "bad leb_cnt on master node");
ubifs_dump_node(c, c->mst_node);
return -EINVAL;
}
dbg_mnt("Auto resizing (master) from %d LEBs to %d LEBs",
old_leb_cnt, c->leb_cnt);
c->lst.empty_lebs += growth;
c->lst.total_free += growth * (long long)c->leb_size;
c->lst.total_dark += growth * (long long)c->dark_wm;
/*
* Reflect changes back onto the master node. N.B. the master
* node gets written immediately whenever mounting (or
* remounting) in read-write mode, so we do not need to write it
* here.
*/
c->mst_node->leb_cnt = cpu_to_le32(c->leb_cnt);
c->mst_node->empty_lebs = cpu_to_le32(c->lst.empty_lebs);
c->mst_node->total_free = cpu_to_le64(c->lst.total_free);
c->mst_node->total_dark = cpu_to_le64(c->lst.total_dark);
}
err = validate_master(c);
if (err)
return err;
err = dbg_old_index_check_init(c, &c->zroot);
return err;
}
/**
* ubifs_write_master - write master node.
* @c: UBIFS file-system description object
*
* This function writes the master node. Returns zero in case of success and a
* negative error code in case of failure. The master node is written twice to
* enable recovery.
*/
int ubifs_write_master(struct ubifs_info *c)
{
int err, lnum, offs, len;
ubifs_assert(!c->ro_media && !c->ro_mount);
if (c->ro_error)
return -EROFS;
lnum = UBIFS_MST_LNUM;
offs = c->mst_offs + c->mst_node_alsz;
len = UBIFS_MST_NODE_SZ;
if (offs + UBIFS_MST_NODE_SZ > c->leb_size) {
err = ubifs_leb_unmap(c, lnum);
if (err)
return err;
offs = 0;
}
c->mst_offs = offs;
c->mst_node->highest_inum = cpu_to_le64(c->highest_inum);
err = ubifs_write_node(c, c->mst_node, len, lnum, offs);
if (err)
return err;
lnum += 1;
if (offs == 0) {
err = ubifs_leb_unmap(c, lnum);
if (err)
return err;
}
err = ubifs_write_node(c, c->mst_node, len, lnum, offs);
return err;
}