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  */
  20 int
  21 befs_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
  57 int
  58 befs_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 }