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/exportfs.h>
  15 #include <linux/slab.h>
  16 #include <linux/buffer_head.h>
  17 #include <linux/vfs.h>
  18
  19 static int efs_statfs(struct dentry *dentry, struct kstatfs *buf);
  20 static int efs_fill_super(struct super_block *s, void *d, int silent);
  21
  22 static int efs_get_sb(struct file_system_type *fs_type,
  23         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
  24 {
  25         return get_sb_bdev(fs_type, flags, dev_name, data, efs_fill_super, mnt);
  26 }
  27
  28 static struct file_system_type efs_fs_type = {
  29         .owner          = THIS_MODULE,
  30         .name           = "efs",
  31         .get_sb         = efs_get_sb,
  32         .kill_sb        = kill_block_super,
  33         .fs_flags       = FS_REQUIRES_DEV,
  34 };
  35
  36 static struct pt_types sgi_pt_types[] = {
  37         {0x00,          "SGI vh"},
  38         {0x01,          "SGI trkrepl"},
  39         {0x02,          "SGI secrepl"},
  40         {0x03,          "SGI raw"},
  41         {0x04,          "SGI bsd"},
  42         {SGI_SYSV,      "SGI sysv"},
  43         {0x06,          "SGI vol"},
  44         {SGI_EFS,       "SGI efs"},
  45         {0x08,          "SGI lv"},
  46         {0x09,          "SGI rlv"},
  47         {0x0A,          "SGI xfs"},
  48         {0x0B,          "SGI xfslog"},
  49         {0x0C,          "SGI xlv"},
  50         {0x82,          "Linux swap"},
  51         {0x83,          "Linux native"},
  52         {0,             NULL}
  53 };
  54
  55
  56 static struct kmem_cache * efs_inode_cachep;
  57
  58 static struct inode *efs_alloc_inode(struct super_block *sb)
  59 {
  60         struct efs_inode_info *ei;
  61         ei = (struct efs_inode_info *)kmem_cache_alloc(efs_inode_cachep, GFP_KERNEL);
  62         if (!ei)
  63                 return NULL;
  64         return &ei->vfs_inode;
  65 }
  66
  67 static void efs_destroy_inode(struct inode *inode)
  68 {
  69         kmem_cache_free(efs_inode_cachep, INODE_INFO(inode));
  70 }
  71
  72 static void init_once(struct kmem_cache *cachep, void *foo)
  73 {
  74         struct efs_inode_info *ei = (struct efs_inode_info *) foo;
  75
  76         inode_init_once(&ei->vfs_inode);
  77 }
  78
  79 static int init_inodecache(void)
  80 {
  81         efs_inode_cachep = kmem_cache_create("efs_inode_cache",
  82                                 sizeof(struct efs_inode_info),
  83                                 0, SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD,
  84                                 init_once);
  85         if (efs_inode_cachep == NULL)
  86                 return -ENOMEM;
  87         return 0;
  88 }
  89
  90 static void destroy_inodecache(void)
  91 {
  92         kmem_cache_destroy(efs_inode_cachep);
  93 }
  94
  95 static void efs_put_super(struct super_block *s)
  96 {
  97         kfree(s->s_fs_info);
  98         s->s_fs_info = NULL;
  99 }
 100
 101 static int efs_remount(struct super_block *sb, int *flags, char *data)
 102 {
 103         *flags |= MS_RDONLY;
 104         return 0;
 105 }
 106
 107 static const struct super_operations efs_superblock_operations = {
 108         .alloc_inode    = efs_alloc_inode,
 109         .destroy_inode  = efs_destroy_inode,
 110         .put_super      = efs_put_super,
 111         .statfs         = efs_statfs,
 112         .remount_fs     = efs_remount,
 113 };
 114
 115 static const struct export_operations efs_export_ops = {
 116         .fh_to_dentry   = efs_fh_to_dentry,
 117         .fh_to_parent   = efs_fh_to_parent,
 118         .get_parent     = efs_get_parent,
 119 };
 120
 121 static int __init init_efs_fs(void) {
 122         int err;
 123         printk("EFS: "EFS_VERSION" - http://aeschi.ch.eu.org/efs/\n");
 124         err = init_inodecache();
 125         if (err)
 126                 goto out1;
 127         err = register_filesystem(&efs_fs_type);
 128         if (err)
 129                 goto out;
 130         return 0;
 131 out:
 132         destroy_inodecache();
 133 out1:
 134         return err;
 135 }
 136
 137 static void __exit exit_efs_fs(void) {
 138         unregister_filesystem(&efs_fs_type);
 139         destroy_inodecache();
 140 }
 141
 142 module_init(init_efs_fs)
 143 module_exit(exit_efs_fs)
 144
 145 static efs_block_t efs_validate_vh(struct volume_header *vh) {
 146         int             i;
 147         __be32          cs, *ui;
 148         int             csum;
 149         efs_block_t     sblock = 0; /* shuts up gcc */
 150         struct pt_types *pt_entry;
 151         int             pt_type, slice = -1;
 152
 153         if (be32_to_cpu(vh->vh_magic) != VHMAGIC) {
 154                 /*
 155                  * assume that we're dealing with a partition and allow
 156                  * read_super() to try and detect a valid superblock
 157                  * on the next block.
 158                  */
 159                 return 0;
 160         }
 161
 162         ui = ((__be32 *) (vh + 1)) - 1;
 163         for(csum = 0; ui >= ((__be32 *) vh);) {
 164                 cs = *ui--;
 165                 csum += be32_to_cpu(cs);
 166         }
 167         if (csum) {
 168                 printk(KERN_INFO "EFS: SGI disklabel: checksum bad, label corrupted\n");
 169                 return 0;
 170         }
 171
 172 #ifdef DEBUG
 173         printk(KERN_DEBUG "EFS: bf: \"%16s\"\n", vh->vh_bootfile);
 174
 175         for(i = 0; i < NVDIR; i++) {
 176                 int     j;
 177                 char    name[VDNAMESIZE+1];
 178
 179                 for(j = 0; j < VDNAMESIZE; j++) {
 180                         name[j] = vh->vh_vd[i].vd_name[j];
 181                 }
 182                 name[j] = (char) 0;
 183
 184                 if (name[0]) {
 185                         printk(KERN_DEBUG "EFS: vh: %8s block: 0x%08x size: 0x%08x\n",
 186                                 name,
 187                                 (int) be32_to_cpu(vh->vh_vd[i].vd_lbn),
 188                                 (int) be32_to_cpu(vh->vh_vd[i].vd_nbytes));
 189                 }
 190         }
 191 #endif
 192
 193         for(i = 0; i < NPARTAB; i++) {
 194                 pt_type = (int) be32_to_cpu(vh->vh_pt[i].pt_type);
 195                 for(pt_entry = sgi_pt_types; pt_entry->pt_name; pt_entry++) {
 196                         if (pt_type == pt_entry->pt_type) break;
 197                 }
 198 #ifdef DEBUG
 199                 if (be32_to_cpu(vh->vh_pt[i].pt_nblks)) {
 200                         printk(KERN_DEBUG "EFS: pt %2d: start: %08d size: %08d type: 0x%02x (%s)\n",
 201                                 i,
 202                                 (int) be32_to_cpu(vh->vh_pt[i].pt_firstlbn),
 203                                 (int) be32_to_cpu(vh->vh_pt[i].pt_nblks),
 204                                 pt_type,
 205                                 (pt_entry->pt_name) ? pt_entry->pt_name : "unknown");
 206                 }
 207 #endif
 208                 if (IS_EFS(pt_type)) {
 209                         sblock = be32_to_cpu(vh->vh_pt[i].pt_firstlbn);
 210                         slice = i;
 211                 }
 212         }
 213
 214         if (slice == -1) {
 215                 printk(KERN_NOTICE "EFS: partition table contained no EFS partitions\n");
 216 #ifdef DEBUG
 217         } else {
 218                 printk(KERN_INFO "EFS: using slice %d (type %s, offset 0x%x)\n",
 219                         slice,
 220                         (pt_entry->pt_name) ? pt_entry->pt_name : "unknown",
 221                         sblock);
 222 #endif
 223         }
 224         return sblock;
 225 }
 226
 227 static int efs_validate_super(struct efs_sb_info *sb, struct efs_super *super) {
 228
 229         if (!IS_EFS_MAGIC(be32_to_cpu(super->fs_magic)))
 230                 return -1;
 231
 232         sb->fs_magic     = be32_to_cpu(super->fs_magic);
 233         sb->total_blocks = be32_to_cpu(super->fs_size);
 234         sb->first_block  = be32_to_cpu(super->fs_firstcg);
 235         sb->group_size   = be32_to_cpu(super->fs_cgfsize);
 236         sb->data_free    = be32_to_cpu(super->fs_tfree);
 237         sb->inode_free   = be32_to_cpu(super->fs_tinode);
 238         sb->inode_blocks = be16_to_cpu(super->fs_cgisize);
 239         sb->total_groups = be16_to_cpu(super->fs_ncg);
 240
 241         return 0;
 242 }
 243
 244 static int efs_fill_super(struct super_block *s, void *d, int silent)
 245 {
 246         struct efs_sb_info *sb;
 247         struct buffer_head *bh;
 248         struct inode *root;
 249         int ret = -EINVAL;
 250
 251         sb = kzalloc(sizeof(struct efs_sb_info), GFP_KERNEL);
 252         if (!sb)
 253                 return -ENOMEM;
 254         s->s_fs_info = sb;
 255
 256         s->s_magic              = EFS_SUPER_MAGIC;
 257         if (!sb_set_blocksize(s, EFS_BLOCKSIZE)) {
 258                 printk(KERN_ERR "EFS: device does not support %d byte blocks\n",
 259                         EFS_BLOCKSIZE);
 260                 goto out_no_fs_ul;
 261         }
 262
 263         /* read the vh (volume header) block */
 264         bh = sb_bread(s, 0);
 265
 266         if (!bh) {
 267                 printk(KERN_ERR "EFS: cannot read volume header\n");
 268                 goto out_no_fs_ul;
 269         }
 270
 271         /*
 272          * if this returns zero then we didn't find any partition table.
 273          * this isn't (yet) an error - just assume for the moment that
 274          * the device is valid and go on to search for a superblock.
 275          */
 276         sb->fs_start = efs_validate_vh((struct volume_header *) bh->b_data);
 277         brelse(bh);
 278
 279         if (sb->fs_start == -1) {
 280                 goto out_no_fs_ul;
 281         }
 282
 283         bh = sb_bread(s, sb->fs_start + EFS_SUPER);
 284         if (!bh) {
 285                 printk(KERN_ERR "EFS: cannot read superblock\n");
 286                 goto out_no_fs_ul;
 287         }
 288
 289         if (efs_validate_super(sb, (struct efs_super *) bh->b_data)) {
 290 #ifdef DEBUG
 291                 printk(KERN_WARNING "EFS: invalid superblock at block %u\n", sb->fs_start + EFS_SUPER);
 292 #endif
 293                 brelse(bh);
 294                 goto out_no_fs_ul;
 295         }
 296         brelse(bh);
 297
 298         if (!(s->s_flags & MS_RDONLY)) {
 299 #ifdef DEBUG
 300                 printk(KERN_INFO "EFS: forcing read-only mode\n");
 301 #endif
 302                 s->s_flags |= MS_RDONLY;
 303         }
 304         s->s_op   = &efs_superblock_operations;
 305         s->s_export_op = &efs_export_ops;
 306         root = efs_iget(s, EFS_ROOTINODE);
 307         if (IS_ERR(root)) {
 308                 printk(KERN_ERR "EFS: get root inode failed\n");
 309                 ret = PTR_ERR(root);
 310                 goto out_no_fs;
 311         }
 312
 313         s->s_root = d_alloc_root(root);
 314         if (!(s->s_root)) {
 315                 printk(KERN_ERR "EFS: get root dentry failed\n");
 316                 iput(root);
 317                 ret = -ENOMEM;
 318                 goto out_no_fs;
 319         }
 320
 321         return 0;
 322
 323 out_no_fs_ul:
 324 out_no_fs:
 325         s->s_fs_info = NULL;
 326         kfree(sb);
 327         return ret;
 328 }
 329
 330 static int efs_statfs(struct dentry *dentry, struct kstatfs *buf) {
 331         struct efs_sb_info *sb = SUPER_INFO(dentry->d_sb);
 332
 333         buf->f_type    = EFS_SUPER_MAGIC;       /* efs magic number */
 334         buf->f_bsize   = EFS_BLOCKSIZE;         /* blocksize */
 335         buf->f_blocks  = sb->total_groups *     /* total data blocks */
 336                         (sb->group_size - sb->inode_blocks);
 337         buf->f_bfree   = sb->data_free;         /* free data blocks */
 338         buf->f_bavail  = sb->data_free;         /* free blocks for non-root */
 339         buf->f_files   = sb->total_groups *     /* total inodes */
 340                         sb->inode_blocks *
 341                         (EFS_BLOCKSIZE / sizeof(struct efs_dinode));
 342         buf->f_ffree   = sb->inode_free;        /* free inodes */
 343         buf->f_fsid.val[0] = (sb->fs_magic >> 16) & 0xffff; /* fs ID */
 344         buf->f_fsid.val[1] =  sb->fs_magic        & 0xffff; /* fs ID */
 345         buf->f_namelen = EFS_MAXNAMELEN;        /* max filename length */
 346
 347         return 0;
 348 }
 349