fs/adfs/super.c

   1 /*
   2  *  linux/fs/adfs/super.c
   3  *
   4  *  Copyright (C) 1997-1999 Russell King
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10 #include <linux/module.h>
  11 #include <linux/init.h>
  12 #include <linux/buffer_head.h>
  13 #include <linux/parser.h>
  14 #include <linux/mount.h>
  15 #include <linux/seq_file.h>
  16 #include <linux/slab.h>
  17 #include <linux/smp_lock.h>
  18 #include <linux/statfs.h>
  19 #include "adfs.h"
  20 #include "dir_f.h"
  21 #include "dir_fplus.h"
  22
  23 #define ADFS_DEFAULT_OWNER_MASK S_IRWXU
  24 #define ADFS_DEFAULT_OTHER_MASK (S_IRWXG | S_IRWXO)
  25
  26 void __adfs_error(struct super_block *sb, const char *function, const char *fmt, ...)
  27 {
  28         char error_buf[128];
  29         va_list args;
  30
  31         va_start(args, fmt);
  32         vsnprintf(error_buf, sizeof(error_buf), fmt, args);
  33         va_end(args);
  34
  35         printk(KERN_CRIT "ADFS-fs error (device %s)%s%s: %s\n",
  36                 sb->s_id, function ? ": " : "",
  37                 function ? function : "", error_buf);
  38 }
  39
  40 static int adfs_checkdiscrecord(struct adfs_discrecord *dr)
  41 {
  42         int i;
  43
  44         /* sector size must be 256, 512 or 1024 bytes */
  45         if (dr->log2secsize != 8 &&
  46             dr->log2secsize != 9 &&
  47             dr->log2secsize != 10)
  48                 return 1;
  49
  50         /* idlen must be at least log2secsize + 3 */
  51         if (dr->idlen < dr->log2secsize + 3)
  52                 return 1;
  53
  54         /* we cannot have such a large disc that we
  55          * are unable to represent sector offsets in
  56          * 32 bits.  This works out at 2.0 TB.
  57          */
  58         if (le32_to_cpu(dr->disc_size_high) >> dr->log2secsize)
  59                 return 1;
  60
  61         /* idlen must be no greater than 19 v2 [1.0] */
  62         if (dr->idlen > 19)
  63                 return 1;
  64
  65         /* reserved bytes should be zero */
  66         for (i = 0; i < sizeof(dr->unused52); i++)
  67                 if (dr->unused52[i] != 0)
  68                         return 1;
  69
  70         return 0;
  71 }
  72
  73 static unsigned char adfs_calczonecheck(struct super_block *sb, unsigned char *map)
  74 {
  75         unsigned int v0, v1, v2, v3;
  76         int i;
  77
  78         v0 = v1 = v2 = v3 = 0;
  79         for (i = sb->s_blocksize - 4; i; i -= 4) {
  80                 v0 += map[i]     + (v3 >> 8);
  81                 v3 &= 0xff;
  82                 v1 += map[i + 1] + (v0 >> 8);
  83                 v0 &= 0xff;
  84                 v2 += map[i + 2] + (v1 >> 8);
  85                 v1 &= 0xff;
  86                 v3 += map[i + 3] + (v2 >> 8);
  87                 v2 &= 0xff;
  88         }
  89         v0 +=           v3 >> 8;
  90         v1 += map[1] + (v0 >> 8);
  91         v2 += map[2] + (v1 >> 8);
  92         v3 += map[3] + (v2 >> 8);
  93
  94         return v0 ^ v1 ^ v2 ^ v3;
  95 }
  96
  97 static int adfs_checkmap(struct super_block *sb, struct adfs_discmap *dm)
  98 {
  99         unsigned char crosscheck = 0, zonecheck = 1;
 100         int i;
 101
 102         for (i = 0; i < ADFS_SB(sb)->s_map_size; i++) {
 103                 unsigned char *map;
 104
 105                 map = dm[i].dm_bh->b_data;
 106
 107                 if (adfs_calczonecheck(sb, map) != map[0]) {
 108                         adfs_error(sb, "zone %d fails zonecheck", i);
 109                         zonecheck = 0;
 110                 }
 111                 crosscheck ^= map[3];
 112         }
 113         if (crosscheck != 0xff)
 114                 adfs_error(sb, "crosscheck != 0xff");
 115         return crosscheck == 0xff && zonecheck;
 116 }
 117
 118 static void adfs_put_super(struct super_block *sb)
 119 {
 120         int i;
 121         struct adfs_sb_info *asb = ADFS_SB(sb);
 122
 123         lock_kernel();
 124
 125         for (i = 0; i < asb->s_map_size; i++)
 126                 brelse(asb->s_map[i].dm_bh);
 127         kfree(asb->s_map);
 128         kfree(asb);
 129         sb->s_fs_info = NULL;
 130
 131         unlock_kernel();
 132 }
 133
 134 static int adfs_show_options(struct seq_file *seq, struct vfsmount *mnt)
 135 {
 136         struct adfs_sb_info *asb = ADFS_SB(mnt->mnt_sb);
 137
 138         if (asb->s_uid != 0)
 139                 seq_printf(seq, ",uid=%u", asb->s_uid);
 140         if (asb->s_gid != 0)
 141                 seq_printf(seq, ",gid=%u", asb->s_gid);
 142         if (asb->s_owner_mask != ADFS_DEFAULT_OWNER_MASK)
 143                 seq_printf(seq, ",ownmask=%o", asb->s_owner_mask);
 144         if (asb->s_other_mask != ADFS_DEFAULT_OTHER_MASK)
 145                 seq_printf(seq, ",othmask=%o", asb->s_other_mask);
 146
 147         return 0;
 148 }
 149
 150 enum {Opt_uid, Opt_gid, Opt_ownmask, Opt_othmask, Opt_err};
 151
 152 static const match_table_t tokens = {
 153         {Opt_uid, "uid=%u"},
 154         {Opt_gid, "gid=%u"},
 155         {Opt_ownmask, "ownmask=%o"},
 156         {Opt_othmask, "othmask=%o"},
 157         {Opt_err, NULL}
 158 };
 159
 160 static int parse_options(struct super_block *sb, char *options)
 161 {
 162         char *p;
 163         struct adfs_sb_info *asb = ADFS_SB(sb);
 164         int option;
 165
 166         if (!options)
 167                 return 0;
 168
 169         while ((p = strsep(&options, ",")) != NULL) {
 170                 substring_t args[MAX_OPT_ARGS];
 171                 int token;
 172                 if (!*p)
 173                         continue;
 174
 175                 token = match_token(p, tokens, args);
 176                 switch (token) {
 177                 case Opt_uid:
 178                         if (match_int(args, &option))
 179                                 return -EINVAL;
 180                         asb->s_uid = option;
 181                         break;
 182                 case Opt_gid:
 183                         if (match_int(args, &option))
 184                                 return -EINVAL;
 185                         asb->s_gid = option;
 186                         break;
 187                 case Opt_ownmask:
 188                         if (match_octal(args, &option))
 189                                 return -EINVAL;
 190                         asb->s_owner_mask = option;
 191                         break;
 192                 case Opt_othmask:
 193                         if (match_octal(args, &option))
 194                                 return -EINVAL;
 195                         asb->s_other_mask = option;
 196                         break;
 197                 default:
 198                         printk("ADFS-fs: unrecognised mount option \"%s\" "
 199                                         "or missing value\n", p);
 200                         return -EINVAL;
 201                 }
 202         }
 203         return 0;
 204 }
 205
 206 static int adfs_remount(struct super_block *sb, int *flags, char *data)
 207 {
 208         *flags |= MS_NODIRATIME;
 209         return parse_options(sb, data);
 210 }
 211
 212 static int adfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 213 {
 214         struct super_block *sb = dentry->d_sb;
 215         struct adfs_sb_info *sbi = ADFS_SB(sb);
 216         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 217
 218         buf->f_type    = ADFS_SUPER_MAGIC;
 219         buf->f_namelen = sbi->s_namelen;
 220         buf->f_bsize   = sb->s_blocksize;
 221         buf->f_blocks  = sbi->s_size;
 222         buf->f_files   = sbi->s_ids_per_zone * sbi->s_map_size;
 223         buf->f_bavail  =
 224         buf->f_bfree   = adfs_map_free(sb);
 225         buf->f_ffree   = (long)(buf->f_bfree * buf->f_files) / (long)buf->f_blocks;
 226         buf->f_fsid.val[0] = (u32)id;
 227         buf->f_fsid.val[1] = (u32)(id >> 32);
 228
 229         return 0;
 230 }
 231
 232 static struct kmem_cache *adfs_inode_cachep;
 233
 234 static struct inode *adfs_alloc_inode(struct super_block *sb)
 235 {
 236         struct adfs_inode_info *ei;
 237         ei = (struct adfs_inode_info *)kmem_cache_alloc(adfs_inode_cachep, GFP_KERNEL);
 238         if (!ei)
 239                 return NULL;
 240         return &ei->vfs_inode;
 241 }
 242
 243 static void adfs_i_callback(struct rcu_head *head)
 244 {
 245         struct inode *inode = container_of(head, struct inode, i_rcu);
 246         INIT_LIST_HEAD(&inode->i_dentry);
 247         kmem_cache_free(adfs_inode_cachep, ADFS_I(inode));
 248 }
 249
 250 static void adfs_destroy_inode(struct inode *inode)
 251 {
 252         call_rcu(&inode->i_rcu, adfs_i_callback);
 253 }
 254
 255 static void init_once(void *foo)
 256 {
 257         struct adfs_inode_info *ei = (struct adfs_inode_info *) foo;
 258
 259         inode_init_once(&ei->vfs_inode);
 260 }
 261
 262 static int init_inodecache(void)
 263 {
 264         adfs_inode_cachep = kmem_cache_create("adfs_inode_cache",
 265                                              sizeof(struct adfs_inode_info),
 266                                              0, (SLAB_RECLAIM_ACCOUNT|
 267                                                 SLAB_MEM_SPREAD),
 268                                              init_once);
 269         if (adfs_inode_cachep == NULL)
 270                 return -ENOMEM;
 271         return 0;
 272 }
 273
 274 static void destroy_inodecache(void)
 275 {
 276         kmem_cache_destroy(adfs_inode_cachep);
 277 }
 278
 279 static const struct super_operations adfs_sops = {
 280         .alloc_inode    = adfs_alloc_inode,
 281         .destroy_inode  = adfs_destroy_inode,
 282         .write_inode    = adfs_write_inode,
 283         .put_super      = adfs_put_super,
 284         .statfs         = adfs_statfs,
 285         .remount_fs     = adfs_remount,
 286         .show_options   = adfs_show_options,
 287 };
 288
 289 static struct adfs_discmap *adfs_read_map(struct super_block *sb, struct adfs_discrecord *dr)
 290 {
 291         struct adfs_discmap *dm;
 292         unsigned int map_addr, zone_size, nzones;
 293         int i, zone;
 294         struct adfs_sb_info *asb = ADFS_SB(sb);
 295
 296         nzones    = asb->s_map_size;
 297         zone_size = (8 << dr->log2secsize) - le16_to_cpu(dr->zone_spare);
 298         map_addr  = (nzones >> 1) * zone_size -
 299                      ((nzones > 1) ? ADFS_DR_SIZE_BITS : 0);
 300         map_addr  = signed_asl(map_addr, asb->s_map2blk);
 301
 302         asb->s_ids_per_zone = zone_size / (asb->s_idlen + 1);
 303
 304         dm = kmalloc(nzones * sizeof(*dm), GFP_KERNEL);
 305         if (dm == NULL) {
 306                 adfs_error(sb, "not enough memory");
 307                 return NULL;
 308         }
 309
 310         for (zone = 0; zone < nzones; zone++, map_addr++) {
 311                 dm[zone].dm_startbit = 0;
 312                 dm[zone].dm_endbit   = zone_size;
 313                 dm[zone].dm_startblk = zone * zone_size - ADFS_DR_SIZE_BITS;
 314                 dm[zone].dm_bh       = sb_bread(sb, map_addr);
 315
 316                 if (!dm[zone].dm_bh) {
 317                         adfs_error(sb, "unable to read map");
 318                         goto error_free;
 319                 }
 320         }
 321
 322         /* adjust the limits for the first and last map zones */
 323         i = zone - 1;
 324         dm[0].dm_startblk = 0;
 325         dm[0].dm_startbit = ADFS_DR_SIZE_BITS;
 326         dm[i].dm_endbit   = (le32_to_cpu(dr->disc_size_high) << (32 - dr->log2bpmb)) +
 327                             (le32_to_cpu(dr->disc_size) >> dr->log2bpmb) +
 328                             (ADFS_DR_SIZE_BITS - i * zone_size);
 329
 330         if (adfs_checkmap(sb, dm))
 331                 return dm;
 332
 333         adfs_error(sb, "map corrupted");
 334
 335 error_free:
 336         while (--zone >= 0)
 337                 brelse(dm[zone].dm_bh);
 338
 339         kfree(dm);
 340         return NULL;
 341 }
 342
 343 static inline unsigned long adfs_discsize(struct adfs_discrecord *dr, int block_bits)
 344 {
 345         unsigned long discsize;
 346
 347         discsize  = le32_to_cpu(dr->disc_size_high) << (32 - block_bits);
 348         discsize |= le32_to_cpu(dr->disc_size) >> block_bits;
 349
 350         return discsize;
 351 }
 352
 353 static int adfs_fill_super(struct super_block *sb, void *data, int silent)
 354 {
 355         struct adfs_discrecord *dr;
 356         struct buffer_head *bh;
 357         struct object_info root_obj;
 358         unsigned char *b_data;
 359         struct adfs_sb_info *asb;
 360         struct inode *root;
 361
 362         lock_kernel();
 363
 364         sb->s_flags |= MS_NODIRATIME;
 365
 366         asb = kzalloc(sizeof(*asb), GFP_KERNEL);
 367         if (!asb) {
 368                 unlock_kernel();
 369                 return -ENOMEM;
 370         }
 371         sb->s_fs_info = asb;
 372
 373         /* set default options */
 374         asb->s_uid = 0;
 375         asb->s_gid = 0;
 376         asb->s_owner_mask = ADFS_DEFAULT_OWNER_MASK;
 377         asb->s_other_mask = ADFS_DEFAULT_OTHER_MASK;
 378
 379         if (parse_options(sb, data))
 380                 goto error;
 381
 382         sb_set_blocksize(sb, BLOCK_SIZE);
 383         if (!(bh = sb_bread(sb, ADFS_DISCRECORD / BLOCK_SIZE))) {
 384                 adfs_error(sb, "unable to read superblock");
 385                 goto error;
 386         }
 387
 388         b_data = bh->b_data + (ADFS_DISCRECORD % BLOCK_SIZE);
 389
 390         if (adfs_checkbblk(b_data)) {
 391                 if (!silent)
 392                         printk("VFS: Can't find an adfs filesystem on dev "
 393                                 "%s.\n", sb->s_id);
 394                 goto error_free_bh;
 395         }
 396
 397         dr = (struct adfs_discrecord *)(b_data + ADFS_DR_OFFSET);
 398
 399         /*
 400          * Do some sanity checks on the ADFS disc record
 401          */
 402         if (adfs_checkdiscrecord(dr)) {
 403                 if (!silent)
 404                         printk("VPS: Can't find an adfs filesystem on dev "
 405                                 "%s.\n", sb->s_id);
 406                 goto error_free_bh;
 407         }
 408
 409         brelse(bh);
 410         if (sb_set_blocksize(sb, 1 << dr->log2secsize)) {
 411                 bh = sb_bread(sb, ADFS_DISCRECORD / sb->s_blocksize);
 412                 if (!bh) {
 413                         adfs_error(sb, "couldn't read superblock on "
 414                                 "2nd try.");
 415                         goto error;
 416                 }
 417                 b_data = bh->b_data + (ADFS_DISCRECORD % sb->s_blocksize);
 418                 if (adfs_checkbblk(b_data)) {
 419                         adfs_error(sb, "disc record mismatch, very weird!");
 420                         goto error_free_bh;
 421                 }
 422                 dr = (struct adfs_discrecord *)(b_data + ADFS_DR_OFFSET);
 423         } else {
 424                 if (!silent)
 425                         printk(KERN_ERR "VFS: Unsupported blocksize on dev "
 426                                 "%s.\n", sb->s_id);
 427                 goto error;
 428         }
 429
 430         /*
 431          * blocksize on this device should now be set to the ADFS log2secsize
 432          */
 433
 434         sb->s_magic             = ADFS_SUPER_MAGIC;
 435         asb->s_idlen            = dr->idlen;
 436         asb->s_map_size         = dr->nzones | (dr->nzones_high << 8);
 437         asb->s_map2blk          = dr->log2bpmb - dr->log2secsize;
 438         asb->s_size             = adfs_discsize(dr, sb->s_blocksize_bits);
 439         asb->s_version          = dr->format_version;
 440         asb->s_log2sharesize    = dr->log2sharesize;
 441
 442         asb->s_map = adfs_read_map(sb, dr);
 443         if (!asb->s_map)
 444                 goto error_free_bh;
 445
 446         brelse(bh);
 447
 448         /*
 449          * set up enough so that we can read an inode
 450          */
 451         sb->s_op = &adfs_sops;
 452
 453         dr = (struct adfs_discrecord *)(asb->s_map[0].dm_bh->b_data + 4);
 454
 455         root_obj.parent_id = root_obj.file_id = le32_to_cpu(dr->root);
 456         root_obj.name_len  = 0;
 457         root_obj.loadaddr  = 0;
 458         root_obj.execaddr  = 0;
 459         root_obj.size      = ADFS_NEWDIR_SIZE;
 460         root_obj.attr      = ADFS_NDA_DIRECTORY   | ADFS_NDA_OWNER_READ |
 461                              ADFS_NDA_OWNER_WRITE | ADFS_NDA_PUBLIC_READ;
 462
 463         /*
 464          * If this is a F+ disk with variable length directories,
 465          * get the root_size from the disc record.
 466          */
 467         if (asb->s_version) {
 468                 root_obj.size = le32_to_cpu(dr->root_size);
 469                 asb->s_dir     = &adfs_fplus_dir_ops;
 470                 asb->s_namelen = ADFS_FPLUS_NAME_LEN;
 471         } else {
 472                 asb->s_dir     = &adfs_f_dir_ops;
 473                 asb->s_namelen = ADFS_F_NAME_LEN;
 474         }
 475
 476         sb->s_d_op = &adfs_dentry_operations;
 477         root = adfs_iget(sb, &root_obj);
 478         sb->s_root = d_alloc_root(root);
 479         if (!sb->s_root) {
 480                 int i;
 481                 iput(root);
 482                 for (i = 0; i < asb->s_map_size; i++)
 483                         brelse(asb->s_map[i].dm_bh);
 484                 kfree(asb->s_map);
 485                 adfs_error(sb, "get root inode failed\n");
 486                 goto error;
 487         }
 488         unlock_kernel();
 489         return 0;
 490
 491 error_free_bh:
 492         brelse(bh);
 493 error:
 494         sb->s_fs_info = NULL;
 495         kfree(asb);
 496         unlock_kernel();
 497         return -EINVAL;
 498 }
 499
 500 static struct dentry *adfs_mount(struct file_system_type *fs_type,
 501         int flags, const char *dev_name, void *data)
 502 {
 503         return mount_bdev(fs_type, flags, dev_name, data, adfs_fill_super);
 504 }
 505
 506 static struct file_system_type adfs_fs_type = {
 507         .owner          = THIS_MODULE,
 508         .name           = "adfs",
 509         .mount          = adfs_mount,
 510         .kill_sb        = kill_block_super,
 511         .fs_flags       = FS_REQUIRES_DEV,
 512 };
 513
 514 static int __init init_adfs_fs(void)
 515 {
 516         int err = init_inodecache();
 517         if (err)
 518                 goto out1;
 519         err = register_filesystem(&adfs_fs_type);
 520         if (err)
 521                 goto out;
 522         return 0;
 523 out:
 524         destroy_inodecache();
 525 out1:
 526         return err;
 527 }
 528
 529 static void __exit exit_adfs_fs(void)
 530 {
 531         unregister_filesystem(&adfs_fs_type);
 532         destroy_inodecache();
 533 }
 534
 535 module_init(init_adfs_fs)
 536 module_exit(exit_adfs_fs)
 537 MODULE_LICENSE("GPL");