LXR linux/fs/befs/super.c

   1/*
   2 * super.c
   3 *
   4 * Copyright (C) 2001-2002 Will Dyson <will_dyson@pobox.com>
   5 *
   6 * Licensed under the GNU GPL. See the file COPYING for details.
   7 *
   8 */
   9
  10#include <linux/fs.h>
  11#include <asm/page.h> /* for PAGE_SIZE */
  12
  13#include "befs.h"
  14#include "super.h"
  15
  16/*
  17 * befs_load_sb -- Read from disk and properly byteswap all the fields
  18 * of the befs superblock
  19 */
  20int
  21befs_load_sb(struct super_block *sb, befs_super_block *disk_sb)
  22{
  23        struct befs_sb_info *befs_sb = BEFS_SB(sb);
  24
  25        /* Check the byte order of the filesystem */
  26        if (disk_sb->fs_byte_order == BEFS_BYTEORDER_NATIVE_LE)
  27                befs_sb->byte_order = BEFS_BYTESEX_LE;
  28        else if (disk_sb->fs_byte_order == BEFS_BYTEORDER_NATIVE_BE)
  29                befs_sb->byte_order = BEFS_BYTESEX_BE;
  30
  31        befs_sb->magic1 = fs32_to_cpu(sb, disk_sb->magic1);
  32        befs_sb->magic2 = fs32_to_cpu(sb, disk_sb->magic2);
  33        befs_sb->magic3 = fs32_to_cpu(sb, disk_sb->magic3);
  34        befs_sb->block_size = fs32_to_cpu(sb, disk_sb->block_size);
  35        befs_sb->block_shift = fs32_to_cpu(sb, disk_sb->block_shift);
  36        befs_sb->num_blocks = fs64_to_cpu(sb, disk_sb->num_blocks);
  37        befs_sb->used_blocks = fs64_to_cpu(sb, disk_sb->used_blocks);
  38        befs_sb->inode_size = fs32_to_cpu(sb, disk_sb->inode_size);
  39
  40        befs_sb->blocks_per_ag = fs32_to_cpu(sb, disk_sb->blocks_per_ag);
  41        befs_sb->ag_shift = fs32_to_cpu(sb, disk_sb->ag_shift);
  42        befs_sb->num_ags = fs32_to_cpu(sb, disk_sb->num_ags);
  43
  44        befs_sb->flags = fs32_to_cpu(sb, disk_sb->flags);
  45
  46        befs_sb->log_blocks = fsrun_to_cpu(sb, disk_sb->log_blocks);
  47        befs_sb->log_start = fs64_to_cpu(sb, disk_sb->log_start);
  48        befs_sb->log_end = fs64_to_cpu(sb, disk_sb->log_end);
  49
  50        befs_sb->root_dir = fsrun_to_cpu(sb, disk_sb->root_dir);
  51        befs_sb->indices = fsrun_to_cpu(sb, disk_sb->indices);
  52        befs_sb->nls = NULL;
  53
  54        return BEFS_OK;
  55}
  56
  57int
  58befs_check_sb(struct super_block *sb)
  59{
  60        struct befs_sb_info *befs_sb = BEFS_SB(sb);
  61
  62        /* Check magic headers of super block */
  63        if ((befs_sb->magic1 != BEFS_SUPER_MAGIC1)
  64            || (befs_sb->magic2 != BEFS_SUPER_MAGIC2)
  65            || (befs_sb->magic3 != BEFS_SUPER_MAGIC3)) {
  66                befs_error(sb, "invalid magic header");
  67                return BEFS_ERR;
  68        }
  69
  70        /*
  71         * Check blocksize of BEFS.
  72         *
  73         * Blocksize of BEFS is 1024, 2048, 4096 or 8192.
  74         */
  75
  76        if ((befs_sb->block_size != 1024)
  77            && (befs_sb->block_size != 2048)
  78            && (befs_sb->block_size != 4096)
  79            && (befs_sb->block_size != 8192)) {
  80                befs_error(sb, "invalid blocksize: %u", befs_sb->block_size);
  81                return BEFS_ERR;
  82        }
  83
  84        if (befs_sb->block_size > PAGE_SIZE) {
  85                befs_error(sb, "blocksize(%u) cannot be larger "
  86                           "than system pagesize(%lu)", befs_sb->block_size,
  87                           PAGE_SIZE);
  88                return BEFS_ERR;
  89        }
  90
  91        /*
  92         * block_shift and block_size encode the same information
  93         * in different ways as a consistency check.
  94         */
  95
  96        if ((1 << befs_sb->block_shift) != befs_sb->block_size) {
  97                befs_error(sb, "block_shift disagrees with block_size. "
  98                           "Corruption likely.");
  99                return BEFS_ERR;
 100        }
 101
 102
 103        /* ag_shift also encodes the same information as blocks_per_ag in a
 104         * different way, non-fatal consistency check
 105         */
 106        if ((1 << befs_sb->ag_shift) != befs_sb->blocks_per_ag)
 107                befs_error(sb, "ag_shift disagrees with blocks_per_ag.");
 108
 109        if (befs_sb->log_start != befs_sb->log_end ||
 110            befs_sb->flags == BEFS_DIRTY) {
 111                befs_error(sb, "Filesystem not clean! There are blocks in the "
 112                           "journal. You must boot into BeOS and mount this "
 113                           "volume to make it clean.");
 114                return BEFS_ERR;
 115        }
 116
 117        return BEFS_OK;
 118}
 119