fs/efs/super.c

   1 /*
   2  * super.c
   3  *
   4  * Copyright (c) 1999 Al Smith
   5  *
   6  * Portions derived from work (c) 1995,1996 Christian Vogelgsang.
   7  */
   8
   9 #include <linux/init.h>
  10 #include <linux/module.h>
  11 #include <linux/locks.h>
  12 #include <linux/efs_fs.h>
  13 #include <linux/efs_vh.h>
  14 #include <linux/efs_fs_sb.h>
  15
  16 static DECLARE_FSTYPE_DEV(efs_fs_type, "efs", efs_read_super);
  17
  18 static struct super_operations efs_superblock_operations = {
  19         read_inode:     efs_read_inode,
  20         statfs:         efs_statfs,
  21 };
  22
  23 static int __init init_efs_fs(void) {
  24         printk("EFS: "EFS_VERSION" - http://aeschi.ch.eu.org/efs/\n");
  25         return register_filesystem(&efs_fs_type);
  26 }
  27
  28 static void __exit exit_efs_fs(void) {
  29         unregister_filesystem(&efs_fs_type);
  30 }
  31
  32 EXPORT_NO_SYMBOLS;
  33
  34 module_init(init_efs_fs)
  35 module_exit(exit_efs_fs)
  36
  37 static efs_block_t efs_validate_vh(struct volume_header *vh) {
  38         int             i;
  39         unsigned int    cs, csum, *ui;
  40         efs_block_t     sblock = 0; /* shuts up gcc */
  41         struct pt_types *pt_entry;
  42         int             pt_type, slice = -1;
  43
  44         if (be32_to_cpu(vh->vh_magic) != VHMAGIC) {
  45                 /*
  46                  * assume that we're dealing with a partition and allow
  47                  * read_super() to try and detect a valid superblock
  48                  * on the next block.
  49                  */
  50                 return 0;
  51         }
  52
  53         ui = ((unsigned int *) (vh + 1)) - 1;
  54         for(csum = 0; ui >= ((unsigned int *) vh);) {
  55                 cs = *ui--;
  56                 csum += be32_to_cpu(cs);
  57         }
  58         if (csum) {
  59                 printk(KERN_INFO "EFS: SGI disklabel: checksum bad, label corrupted\n");
  60                 return 0;
  61         }
  62
  63 #ifdef DEBUG
  64         printk(KERN_DEBUG "EFS: bf: \"%16s\"\n", vh->vh_bootfile);
  65
  66         for(i = 0; i < NVDIR; i++) {
  67                 int     j;
  68                 char    name[VDNAMESIZE+1];
  69
  70                 for(j = 0; j < VDNAMESIZE; j++) {
  71                         name[j] = vh->vh_vd[i].vd_name[j];
  72                 }
  73                 name[j] = (char) 0;
  74
  75                 if (name[0]) {
  76                         printk(KERN_DEBUG "EFS: vh: %8s block: 0x%08x size: 0x%08x\n",
  77                                 name,
  78                                 (int) be32_to_cpu(vh->vh_vd[i].vd_lbn),
  79                                 (int) be32_to_cpu(vh->vh_vd[i].vd_nbytes));
  80                 }
  81         }
  82 #endif
  83
  84         for(i = 0; i < NPARTAB; i++) {
  85                 pt_type = (int) be32_to_cpu(vh->vh_pt[i].pt_type);
  86                 for(pt_entry = sgi_pt_types; pt_entry->pt_name; pt_entry++) {
  87                         if (pt_type == pt_entry->pt_type) break;
  88                 }
  89 #ifdef DEBUG
  90                 if (be32_to_cpu(vh->vh_pt[i].pt_nblks)) {
  91                         printk(KERN_DEBUG "EFS: pt %2d: start: %08d size: %08d type: 0x%02x (%s)\n",
  92                                 i,
  93                                 (int) be32_to_cpu(vh->vh_pt[i].pt_firstlbn),
  94                                 (int) be32_to_cpu(vh->vh_pt[i].pt_nblks),
  95                                 pt_type,
  96                                 (pt_entry->pt_name) ? pt_entry->pt_name : "unknown");
  97                 }
  98 #endif
  99                 if (IS_EFS(pt_type)) {
 100                         sblock = be32_to_cpu(vh->vh_pt[i].pt_firstlbn);
 101                         slice = i;
 102                 }
 103         }
 104
 105         if (slice == -1) {
 106                 printk(KERN_NOTICE "EFS: partition table contained no EFS partitions\n");
 107 #ifdef DEBUG
 108         } else {
 109                 printk(KERN_INFO "EFS: using slice %d (type %s, offset 0x%x)\n",
 110                         slice,
 111                         (pt_entry->pt_name) ? pt_entry->pt_name : "unknown",
 112                         sblock);
 113 #endif
 114         }
 115         return(sblock);
 116 }
 117
 118 static int efs_validate_super(struct efs_sb_info *sb, struct efs_super *super) {
 119
 120         if (!IS_EFS_MAGIC(be32_to_cpu(super->fs_magic))) return -1;
 121
 122         sb->fs_magic     = be32_to_cpu(super->fs_magic);
 123         sb->total_blocks = be32_to_cpu(super->fs_size);
 124         sb->first_block  = be32_to_cpu(super->fs_firstcg);
 125         sb->group_size   = be32_to_cpu(super->fs_cgfsize);
 126         sb->data_free    = be32_to_cpu(super->fs_tfree);
 127         sb->inode_free   = be32_to_cpu(super->fs_tinode);
 128         sb->inode_blocks = be16_to_cpu(super->fs_cgisize);
 129         sb->total_groups = be16_to_cpu(super->fs_ncg);
 130
 131         return 0;
 132 }
 133
 134 struct super_block *efs_read_super(struct super_block *s, void *d, int silent) {
 135         kdev_t dev = s->s_dev;
 136         struct efs_sb_info *sb;
 137         struct buffer_head *bh;
 138
 139         sb = SUPER_INFO(s);
 140
 141         set_blocksize(dev, EFS_BLOCKSIZE);
 142
 143         /* read the vh (volume header) block */
 144         bh = bread(dev, 0, EFS_BLOCKSIZE);
 145
 146         if (!bh) {
 147                 printk(KERN_ERR "EFS: cannot read volume header\n");
 148                 goto out_no_fs_ul;
 149         }
 150
 151         /*
 152          * if this returns zero then we didn't find any partition table.
 153          * this isn't (yet) an error - just assume for the moment that
 154          * the device is valid and go on to search for a superblock.
 155          */
 156         sb->fs_start = efs_validate_vh((struct volume_header *) bh->b_data);
 157         brelse(bh);
 158
 159         if (sb->fs_start == -1) {
 160                 goto out_no_fs_ul;
 161         }
 162
 163         bh = bread(dev, sb->fs_start + EFS_SUPER, EFS_BLOCKSIZE);
 164         if (!bh) {
 165                 printk(KERN_ERR "EFS: cannot read superblock\n");
 166                 goto out_no_fs_ul;
 167         }
 168
 169         if (efs_validate_super(sb, (struct efs_super *) bh->b_data)) {
 170 #ifdef DEBUG
 171                 printk(KERN_WARNING "EFS: invalid superblock at block %u\n", sb->fs_start + EFS_SUPER);
 172 #endif
 173                 brelse(bh);
 174                 goto out_no_fs_ul;
 175         }
 176         brelse(bh);
 177
 178         s->s_magic              = EFS_SUPER_MAGIC;
 179         s->s_blocksize          = EFS_BLOCKSIZE;
 180         s->s_blocksize_bits     = EFS_BLOCKSIZE_BITS;
 181         if (!(s->s_flags & MS_RDONLY)) {
 182 #ifdef DEBUG
 183                 printk(KERN_INFO "EFS: forcing read-only mode\n");
 184 #endif
 185                 s->s_flags |= MS_RDONLY;
 186         }
 187         s->s_op   = &efs_superblock_operations;
 188         s->s_root = d_alloc_root(iget(s, EFS_ROOTINODE));
 189
 190         if (!(s->s_root)) {
 191                 printk(KERN_ERR "EFS: get root inode failed\n");
 192                 goto out_no_fs;
 193         }
 194
 195         return(s);
 196
 197 out_no_fs_ul:
 198 out_no_fs:
 199         return(NULL);
 200 }
 201
 202 int efs_statfs(struct super_block *s, struct statfs *buf) {
 203         struct efs_sb_info *sb = SUPER_INFO(s);
 204
 205         buf->f_type    = EFS_SUPER_MAGIC;       /* efs magic number */
 206         buf->f_bsize   = EFS_BLOCKSIZE;         /* blocksize */
 207         buf->f_blocks  = sb->total_groups *     /* total data blocks */
 208                         (sb->group_size - sb->inode_blocks);
 209         buf->f_bfree   = sb->data_free;         /* free data blocks */
 210         buf->f_bavail  = sb->data_free;         /* free blocks for non-root */
 211         buf->f_files   = sb->total_groups *     /* total inodes */
 212                         sb->inode_blocks *
 213                         (EFS_BLOCKSIZE / sizeof(struct efs_dinode));
 214         buf->f_ffree   = sb->inode_free;        /* free inodes */
 215         buf->f_fsid.val[0] = (sb->fs_magic >> 16) & 0xffff; /* fs ID */
 216         buf->f_fsid.val[1] =  sb->fs_magic        & 0xffff; /* fs ID */
 217         buf->f_namelen = EFS_MAXNAMELEN;        /* max filename length */
 218
 219         return 0;
 220 }
 221