master.c

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/*
 * 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"

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("unexpected node type %d master LEB %d:%d",
          snod->type, lnum, snod->offs);
    ubifs_scan_destroy(sleb);
    return -EINVAL;
}

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("bad master node at offset %d error %d", c->mst_offs, err);
    ubifs_dump_node(c, c->mst_node);
    return -EINVAL;
}

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("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;
}

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;
}