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/efs_fs.h>
  12 #include <linux/efs_vh.h>
  13 #include <linux/efs_fs_sb.h>
  14 #include <linux/slab.h>
  15 #include <linux/buffer_head.h>
  16 #include <linux/vfs.h>
  17
  18 static int efs_statfs(struct dentry *dentry, struct kstatfs *buf);
  19 static int efs_fill_super(struct super_block *s, void *d, int silent);
  20
  21 static int efs_get_sb(struct file_system_type *fs_type,
  22         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
  23 {
  24         return get_sb_bdev(fs_type, flags, dev_name, data, efs_fill_super, mnt);
  25 }
  26
  27 static struct file_system_type efs_fs_type = {
  28         .owner          = THIS_MODULE,
  29         .name           = "efs",
  30         .get_sb         = efs_get_sb,
  31         .kill_sb        = kill_block_super,
  32         .fs_flags       = FS_REQUIRES_DEV,
  33 };
  34
  35 static struct pt_types sgi_pt_types[] = {
  36         {0x00,          "SGI vh"},
  37         {0x01,          "SGI trkrepl"},
  38         {0x02,          "SGI secrepl"},
  39         {0x03,          "SGI raw"},
  40         {0x04,          "SGI bsd"},
  41         {SGI_SYSV,      "SGI sysv"},
  42         {0x06,          "SGI vol"},
  43         {SGI_EFS,       "SGI efs"},
  44         {0x08,          "SGI lv"},
  45         {0x09,          "SGI rlv"},
  46         {0x0A,          "SGI xfs"},
  47         {0x0B,          "SGI xfslog"},
  48         {0x0C,          "SGI xlv"},
  49         {0x82,          "Linux swap"},
  50         {0x83,          "Linux native"},
  51         {0,             NULL}
  52 };
  53
  54
  55 static struct kmem_cache * efs_inode_cachep;
  56
  57 static struct inode *efs_alloc_inode(struct super_block *sb)
  58 {
  59         struct efs_inode_info *ei;
  60         ei = (struct efs_inode_info *)kmem_cache_alloc(efs_inode_cachep, GFP_KERNEL);
  61         if (!ei)
  62                 return NULL;
  63         return &ei->vfs_inode;
  64 }
  65
  66 static void efs_destroy_inode(struct inode *inode)
  67 {
  68         kmem_cache_free(efs_inode_cachep, INODE_INFO(inode));
  69 }
  70
  71 static void init_once(void * foo, struct kmem_cache * cachep, unsigned long flags)
  72 {
  73         struct efs_inode_info *ei = (struct efs_inode_info *) foo;
  74
  75         inode_init_once(&ei->vfs_inode);
  76 }
  77
  78 static int init_inodecache(void)
  79 {
  80         efs_inode_cachep = kmem_cache_create("efs_inode_cache",
  81                                 sizeof(struct efs_inode_info),
  82                                 0, SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD,
  83                                 init_once, NULL);
  84         if (efs_inode_cachep == NULL)
  85                 return -ENOMEM;
  86         return 0;
  87 }
  88
  89 static void destroy_inodecache(void)
  90 {
  91         kmem_cache_destroy(efs_inode_cachep);
  92 }
  93
  94 static void efs_put_super(struct super_block *s)
  95 {
  96         kfree(s->s_fs_info);
  97         s->s_fs_info = NULL;
  98 }
  99
 100 static int efs_remount(struct super_block *sb, int *flags, char *data)
 101 {
 102         *flags |= MS_RDONLY;
 103         return 0;
 104 }
 105
 106 static const struct super_operations efs_superblock_operations = {
 107         .alloc_inode    = efs_alloc_inode,
 108         .destroy_inode  = efs_destroy_inode,
 109         .read_inode     = efs_read_inode,
 110         .put_super      = efs_put_super,
 111         .statfs         = efs_statfs,
 112         .remount_fs     = efs_remount,
 113 };
 114
 115 static struct export_operations efs_export_ops = {
 116         .get_parent     = efs_get_parent,
 117 };
 118
 119 static int __init init_efs_fs(void) {
 120         int err;
 121         printk("EFS: "EFS_VERSION" - http://aeschi.ch.eu.org/efs/\n");
 122         err = init_inodecache();
 123         if (err)
 124                 goto out1;
 125         err = register_filesystem(&efs_fs_type);
 126         if (err)
 127                 goto out;
 128         return 0;
 129 out:
 130         destroy_inodecache();
 131 out1:
 132         return err;
 133 }
 134
 135 static void __exit exit_efs_fs(void) {
 136         unregister_filesystem(&efs_fs_type);
 137         destroy_inodecache();
 138 }
 139
 140 module_init(init_efs_fs)
 141 module_exit(exit_efs_fs)
 142
 143 static efs_block_t efs_validate_vh(struct volume_header *vh) {
 144         int             i;
 145         __be32          cs, *ui;
 146         int             csum;
 147         efs_block_t     sblock = 0; /* shuts up gcc */
 148         struct pt_types *pt_entry;
 149         int             pt_type, slice = -1;
 150
 151         if (be32_to_cpu(vh->vh_magic) != VHMAGIC) {
 152                 /*
 153                  * assume that we're dealing with a partition and allow
 154                  * read_super() to try and detect a valid superblock
 155                  * on the next block.
 156                  */
 157                 return 0;
 158         }
 159
 160         ui = ((__be32 *) (vh + 1)) - 1;
 161         for(csum = 0; ui >= ((__be32 *) vh);) {
 162                 cs = *ui--;
 163                 csum += be32_to_cpu(cs);
 164         }
 165         if (csum) {
 166                 printk(KERN_INFO "EFS: SGI disklabel: checksum bad, label corrupted\n");
 167                 return 0;
 168         }
 169
 170 #ifdef DEBUG
 171         printk(KERN_DEBUG "EFS: bf: \"%16s\"\n", vh->vh_bootfile);
 172
 173         for(i = 0; i < NVDIR; i++) {
 174                 int     j;
 175                 char    name[VDNAMESIZE+1];
 176
 177                 for(j = 0; j < VDNAMESIZE; j++) {
 178                         name[j] = vh->vh_vd[i].vd_name[j];
 179                 }
 180                 name[j] = (char) 0;
 181
 182                 if (name[0]) {
 183                         printk(KERN_DEBUG "EFS: vh: %8s block: 0x%08x size: 0x%08x\n",
 184                                 name,
 185                                 (int) be32_to_cpu(vh->vh_vd[i].vd_lbn),
 186                                 (int) be32_to_cpu(vh->vh_vd[i].vd_nbytes));
 187                 }
 188         }
 189 #endif
 190
 191         for(i = 0; i < NPARTAB; i++) {
 192                 pt_type = (int) be32_to_cpu(vh->vh_pt[i].pt_type);
 193                 for(pt_entry = sgi_pt_types; pt_entry->pt_name; pt_entry++) {
 194                         if (pt_type == pt_entry->pt_type) break;
 195                 }
 196 #ifdef DEBUG
 197                 if (be32_to_cpu(vh->vh_pt[i].pt_nblks)) {
 198                         printk(KERN_DEBUG "EFS: pt %2d: start: %08d size: %08d type: 0x%02x (%s)\n",
 199                                 i,
 200                                 (int) be32_to_cpu(vh->vh_pt[i].pt_firstlbn),
 201                                 (int) be32_to_cpu(vh->vh_pt[i].pt_nblks),
 202                                 pt_type,
 203                                 (pt_entry->pt_name) ? pt_entry->pt_name : "unknown");
 204                 }
 205 #endif
 206                 if (IS_EFS(pt_type)) {
 207                         sblock = be32_to_cpu(vh->vh_pt[i].pt_firstlbn);
 208                         slice = i;
 209                 }
 210         }
 211
 212         if (slice == -1) {
 213                 printk(KERN_NOTICE "EFS: partition table contained no EFS partitions\n");
 214 #ifdef DEBUG
 215         } else {
 216                 printk(KERN_INFO "EFS: using slice %d (type %s, offset 0x%x)\n",
 217                         slice,
 218                         (pt_entry->pt_name) ? pt_entry->pt_name : "unknown",
 219                         sblock);
 220 #endif
 221         }
 222         return sblock;
 223 }
 224
 225 static int efs_validate_super(struct efs_sb_info *sb, struct efs_super *super) {
 226
 227         if (!IS_EFS_MAGIC(be32_to_cpu(super->fs_magic)))
 228                 return -1;
 229
 230         sb->fs_magic     = be32_to_cpu(super->fs_magic);
 231         sb->total_blocks = be32_to_cpu(super->fs_size);
 232         sb->first_block  = be32_to_cpu(super->fs_firstcg);
 233         sb->group_size   = be32_to_cpu(super->fs_cgfsize);
 234         sb->data_free    = be32_to_cpu(super->fs_tfree);
 235         sb->inode_free   = be32_to_cpu(super->fs_tinode);
 236         sb->inode_blocks = be16_to_cpu(super->fs_cgisize);
 237         sb->total_groups = be16_to_cpu(super->fs_ncg);
 238
 239         return 0;
 240 }
 241
 242 static int efs_fill_super(struct super_block *s, void *d, int silent)
 243 {
 244         struct efs_sb_info *sb;
 245         struct buffer_head *bh;
 246         struct inode *root;
 247
 248         sb = kzalloc(sizeof(struct efs_sb_info), GFP_KERNEL);
 249         if (!sb)
 250                 return -ENOMEM;
 251         s->s_fs_info = sb;
 252
 253         s->s_magic              = EFS_SUPER_MAGIC;
 254         if (!sb_set_blocksize(s, EFS_BLOCKSIZE)) {
 255                 printk(KERN_ERR "EFS: device does not support %d byte blocks\n",
 256                         EFS_BLOCKSIZE);
 257                 goto out_no_fs_ul;
 258         }
 259
 260         /* read the vh (volume header) block */
 261         bh = sb_bread(s, 0);
 262
 263         if (!bh) {
 264                 printk(KERN_ERR "EFS: cannot read volume header\n");
 265                 goto out_no_fs_ul;
 266         }
 267
 268         /*
 269          * if this returns zero then we didn't find any partition table.
 270          * this isn't (yet) an error - just assume for the moment that
 271          * the device is valid and go on to search for a superblock.
 272          */
 273         sb->fs_start = efs_validate_vh((struct volume_header *) bh->b_data);
 274         brelse(bh);
 275
 276         if (sb->fs_start == -1) {
 277                 goto out_no_fs_ul;
 278         }
 279
 280         bh = sb_bread(s, sb->fs_start + EFS_SUPER);
 281         if (!bh) {
 282                 printk(KERN_ERR "EFS: cannot read superblock\n");
 283                 goto out_no_fs_ul;
 284         }
 285
 286         if (efs_validate_super(sb, (struct efs_super *) bh->b_data)) {
 287 #ifdef DEBUG
 288                 printk(KERN_WARNING "EFS: invalid superblock at block %u\n", sb->fs_start + EFS_SUPER);
 289 #endif
 290                 brelse(bh);
 291                 goto out_no_fs_ul;
 292         }
 293         brelse(bh);
 294
 295         if (!(s->s_flags & MS_RDONLY)) {
 296 #ifdef DEBUG
 297                 printk(KERN_INFO "EFS: forcing read-only mode\n");
 298 #endif
 299                 s->s_flags |= MS_RDONLY;
 300         }
 301         s->s_op   = &efs_superblock_operations;
 302         s->s_export_op = &efs_export_ops;
 303         root = iget(s, EFS_ROOTINODE);
 304         s->s_root = d_alloc_root(root);
 305
 306         if (!(s->s_root)) {
 307                 printk(KERN_ERR "EFS: get root inode failed\n");
 308                 iput(root);
 309                 goto out_no_fs;
 310         }
 311
 312         return 0;
 313
 314 out_no_fs_ul:
 315 out_no_fs:
 316         s->s_fs_info = NULL;
 317         kfree(sb);
 318         return -EINVAL;
 319 }
 320
 321 static int efs_statfs(struct dentry *dentry, struct kstatfs *buf) {
 322         struct efs_sb_info *sb = SUPER_INFO(dentry->d_sb);
 323
 324         buf->f_type    = EFS_SUPER_MAGIC;       /* efs magic number */
 325         buf->f_bsize   = EFS_BLOCKSIZE;         /* blocksize */
 326         buf->f_blocks  = sb->total_groups *     /* total data blocks */
 327                         (sb->group_size - sb->inode_blocks);
 328         buf->f_bfree   = sb->data_free;         /* free data blocks */
 329         buf->f_bavail  = sb->data_free;         /* free blocks for non-root */
 330         buf->f_files   = sb->total_groups *     /* total inodes */
 331                         sb->inode_blocks *
 332                         (EFS_BLOCKSIZE / sizeof(struct efs_dinode));
 333         buf->f_ffree   = sb->inode_free;        /* free inodes */
 334         buf->f_fsid.val[0] = (sb->fs_magic >> 16) & 0xffff; /* fs ID */
 335         buf->f_fsid.val[1] =  sb->fs_magic        & 0xffff; /* fs ID */
 336         buf->f_namelen = EFS_MAXNAMELEN;        /* max filename length */
 337
 338         return 0;
 339 }
 340