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/statfs.h>
  18 #include "adfs.h"
  19 #include "dir_f.h"
  20 #include "dir_fplus.h"
  21
  22 #define ADFS_DEFAULT_OWNER_MASK S_IRWXU
  23 #define ADFS_DEFAULT_OTHER_MASK (S_IRWXG | S_IRWXO)
  24
  25 void __adfs_error(struct super_block *sb, const char *function, const char *fmt, ...)
  26 {
  27         char error_buf[128];
  28         va_list args;
  29
  30         va_start(args, fmt);
  31         vsnprintf(error_buf, sizeof(error_buf), fmt, args);
  32         va_end(args);
  33
  34         printk(KERN_CRIT "ADFS-fs error (device %s)%s%s: %s\n",
  35                 sb->s_id, function ? ": " : "",
  36                 function ? function : "", error_buf);
  37 }
  38
  39 static int adfs_checkdiscrecord(struct adfs_discrecord *dr)
  40 {
  41         int i;
  42
  43         /* sector size must be 256, 512 or 1024 bytes */
  44         if (dr->log2secsize != 8 &&
  45             dr->log2secsize != 9 &&
  46             dr->log2secsize != 10)
  47                 return 1;
  48
  49         /* idlen must be at least log2secsize + 3 */
  50         if (dr->idlen < dr->log2secsize + 3)
  51                 return 1;
  52
  53         /* we cannot have such a large disc that we
  54          * are unable to represent sector offsets in
  55          * 32 bits.  This works out at 2.0 TB.
  56          */
  57         if (le32_to_cpu(dr->disc_size_high) >> dr->log2secsize)
  58                 return 1;
  59
  60         /* idlen must be no greater than 19 v2 [1.0] */
  61         if (dr->idlen > 19)
  62                 return 1;
  63
  64         /* reserved bytes should be zero */
  65         for (i = 0; i < sizeof(dr->unused52); i++)
  66                 if (dr->unused52[i] != 0)
  67                         return 1;
  68
  69         return 0;
  70 }
  71
  72 static unsigned char adfs_calczonecheck(struct super_block *sb, unsigned char *map)
  73 {
  74         unsigned int v0, v1, v2, v3;
  75         int i;
  76
  77         v0 = v1 = v2 = v3 = 0;
  78         for (i = sb->s_blocksize - 4; i; i -= 4) {
  79                 v0 += map[i]     + (v3 >> 8);
  80                 v3 &= 0xff;
  81                 v1 += map[i + 1] + (v0 >> 8);
  82                 v0 &= 0xff;
  83                 v2 += map[i + 2] + (v1 >> 8);
  84                 v1 &= 0xff;
  85                 v3 += map[i + 3] + (v2 >> 8);
  86                 v2 &= 0xff;
  87         }
  88         v0 +=           v3 >> 8;
  89         v1 += map[1] + (v0 >> 8);
  90         v2 += map[2] + (v1 >> 8);
  91         v3 += map[3] + (v2 >> 8);
  92
  93         return v0 ^ v1 ^ v2 ^ v3;
  94 }
  95
  96 static int adfs_checkmap(struct super_block *sb, struct adfs_discmap *dm)
  97 {
  98         unsigned char crosscheck = 0, zonecheck = 1;
  99         int i;
 100
 101         for (i = 0; i < ADFS_SB(sb)->s_map_size; i++) {
 102                 unsigned char *map;
 103
 104                 map = dm[i].dm_bh->b_data;
 105
 106                 if (adfs_calczonecheck(sb, map) != map[0]) {
 107                         adfs_error(sb, "zone %d fails zonecheck", i);
 108                         zonecheck = 0;
 109                 }
 110                 crosscheck ^= map[3];
 111         }
 112         if (crosscheck != 0xff)
 113                 adfs_error(sb, "crosscheck != 0xff");
 114         return crosscheck == 0xff && zonecheck;
 115 }
 116
 117 static void adfs_put_super(struct super_block *sb)
 118 {
 119         int i;
 120         struct adfs_sb_info *asb = ADFS_SB(sb);
 121
 122         for (i = 0; i < asb->s_map_size; i++)
 123                 brelse(asb->s_map[i].dm_bh);
 124         kfree(asb->s_map);
 125         kfree(asb);
 126         sb->s_fs_info = NULL;
 127 }
 128
 129 static int adfs_show_options(struct seq_file *seq, struct dentry *root)
 130 {
 131         struct adfs_sb_info *asb = ADFS_SB(root->d_sb);
 132
 133         if (asb->s_uid != 0)
 134                 seq_printf(seq, ",uid=%u", asb->s_uid);
 135         if (asb->s_gid != 0)
 136                 seq_printf(seq, ",gid=%u", asb->s_gid);
 137         if (asb->s_owner_mask != ADFS_DEFAULT_OWNER_MASK)
 138                 seq_printf(seq, ",ownmask=%o", asb->s_owner_mask);
 139         if (asb->s_other_mask != ADFS_DEFAULT_OTHER_MASK)
 140                 seq_printf(seq, ",othmask=%o", asb->s_other_mask);
 141         if (asb->s_ftsuffix != 0)
 142                 seq_printf(seq, ",ftsuffix=%u", asb->s_ftsuffix);
 143
 144         return 0;
 145 }
 146
 147 enum {Opt_uid, Opt_gid, Opt_ownmask, Opt_othmask, Opt_ftsuffix, Opt_err};
 148
 149 static const match_table_t tokens = {
 150         {Opt_uid, "uid=%u"},
 151         {Opt_gid, "gid=%u"},
 152         {Opt_ownmask, "ownmask=%o"},
 153         {Opt_othmask, "othmask=%o"},
 154         {Opt_ftsuffix, "ftsuffix=%u"},
 155         {Opt_err, NULL}
 156 };
 157
 158 static int parse_options(struct super_block *sb, char *options)
 159 {
 160         char *p;
 161         struct adfs_sb_info *asb = ADFS_SB(sb);
 162         int option;
 163
 164         if (!options)
 165                 return 0;
 166
 167         while ((p = strsep(&options, ",")) != NULL) {
 168                 substring_t args[MAX_OPT_ARGS];
 169                 int token;
 170                 if (!*p)
 171                         continue;
 172
 173                 token = match_token(p, tokens, args);
 174                 switch (token) {
 175                 case Opt_uid:
 176                         if (match_int(args, &option))
 177                                 return -EINVAL;
 178                         asb->s_uid = option;
 179                         break;
 180                 case Opt_gid:
 181                         if (match_int(args, &option))
 182                                 return -EINVAL;
 183                         asb->s_gid = option;
 184                         break;
 185                 case Opt_ownmask:
 186                         if (match_octal(args, &option))
 187                                 return -EINVAL;
 188                         asb->s_owner_mask = option;
 189                         break;
 190                 case Opt_othmask:
 191                         if (match_octal(args, &option))
 192                                 return -EINVAL;
 193                         asb->s_other_mask = option;
 194                         break;
 195                 case Opt_ftsuffix:
 196                         if (match_int(args, &option))
 197                                 return -EINVAL;
 198                         asb->s_ftsuffix = option;
 199                         break;
 200                 default:
 201                         printk("ADFS-fs: unrecognised mount option \"%s\" "
 202                                         "or missing value\n", p);
 203                         return -EINVAL;
 204                 }
 205         }
 206         return 0;
 207 }
 208
 209 static int adfs_remount(struct super_block *sb, int *flags, char *data)
 210 {
 211         *flags |= MS_NODIRATIME;
 212         return parse_options(sb, data);
 213 }
 214
 215 static int adfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 216 {
 217         struct super_block *sb = dentry->d_sb;
 218         struct adfs_sb_info *sbi = ADFS_SB(sb);
 219         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 220
 221         buf->f_type    = ADFS_SUPER_MAGIC;
 222         buf->f_namelen = sbi->s_namelen;
 223         buf->f_bsize   = sb->s_blocksize;
 224         buf->f_blocks  = sbi->s_size;
 225         buf->f_files   = sbi->s_ids_per_zone * sbi->s_map_size;
 226         buf->f_bavail  =
 227         buf->f_bfree   = adfs_map_free(sb);
 228         buf->f_ffree   = (long)(buf->f_bfree * buf->f_files) / (long)buf->f_blocks;
 229         buf->f_fsid.val[0] = (u32)id;
 230         buf->f_fsid.val[1] = (u32)(id >> 32);
 231
 232         return 0;
 233 }
 234
 235 static struct kmem_cache *adfs_inode_cachep;
 236
 237 static struct inode *adfs_alloc_inode(struct super_block *sb)
 238 {
 239         struct adfs_inode_info *ei;
 240         ei = (struct adfs_inode_info *)kmem_cache_alloc(adfs_inode_cachep, GFP_KERNEL);
 241         if (!ei)
 242                 return NULL;
 243         return &ei->vfs_inode;
 244 }
 245
 246 static void adfs_i_callback(struct rcu_head *head)
 247 {
 248         struct inode *inode = container_of(head, struct inode, i_rcu);
 249         INIT_LIST_HEAD(&inode->i_dentry);
 250         kmem_cache_free(adfs_inode_cachep, ADFS_I(inode));
 251 }
 252
 253 static void adfs_destroy_inode(struct inode *inode)
 254 {
 255         call_rcu(&inode->i_rcu, adfs_i_callback);
 256 }
 257
 258 static void init_once(void *foo)
 259 {
 260         struct adfs_inode_info *ei = (struct adfs_inode_info *) foo;
 261
 262         inode_init_once(&ei->vfs_inode);
 263 }
 264
 265 static int init_inodecache(void)
 266 {
 267         adfs_inode_cachep = kmem_cache_create("adfs_inode_cache",
 268                                              sizeof(struct adfs_inode_info),
 269                                              0, (SLAB_RECLAIM_ACCOUNT|
 270                                                 SLAB_MEM_SPREAD),
 271                                              init_once);
 272         if (adfs_inode_cachep == NULL)
 273                 return -ENOMEM;
 274         return 0;
 275 }
 276
 277 static void destroy_inodecache(void)
 278 {
 279         kmem_cache_destroy(adfs_inode_cachep);
 280 }
 281
 282 static const struct super_operations adfs_sops = {
 283         .alloc_inode    = adfs_alloc_inode,
 284         .destroy_inode  = adfs_destroy_inode,
 285         .write_inode    = adfs_write_inode,
 286         .put_super      = adfs_put_super,
 287         .statfs         = adfs_statfs,
 288         .remount_fs     = adfs_remount,
 289         .show_options   = adfs_show_options,
 290 };
 291
 292 static struct adfs_discmap *adfs_read_map(struct super_block *sb, struct adfs_discrecord *dr)
 293 {
 294         struct adfs_discmap *dm;
 295         unsigned int map_addr, zone_size, nzones;
 296         int i, zone;
 297         struct adfs_sb_info *asb = ADFS_SB(sb);
 298
 299         nzones    = asb->s_map_size;
 300         zone_size = (8 << dr->log2secsize) - le16_to_cpu(dr->zone_spare);
 301         map_addr  = (nzones >> 1) * zone_size -
 302                      ((nzones > 1) ? ADFS_DR_SIZE_BITS : 0);
 303         map_addr  = signed_asl(map_addr, asb->s_map2blk);
 304
 305         asb->s_ids_per_zone = zone_size / (asb->s_idlen + 1);
 306
 307         dm = kmalloc(nzones * sizeof(*dm), GFP_KERNEL);
 308         if (dm == NULL) {
 309                 adfs_error(sb, "not enough memory");
 310                 return NULL;
 311         }
 312
 313         for (zone = 0; zone < nzones; zone++, map_addr++) {
 314                 dm[zone].dm_startbit = 0;
 315                 dm[zone].dm_endbit   = zone_size;
 316                 dm[zone].dm_startblk = zone * zone_size - ADFS_DR_SIZE_BITS;
 317                 dm[zone].dm_bh       = sb_bread(sb, map_addr);
 318
 319                 if (!dm[zone].dm_bh) {
 320                         adfs_error(sb, "unable to read map");
 321                         goto error_free;
 322                 }
 323         }
 324
 325         /* adjust the limits for the first and last map zones */
 326         i = zone - 1;
 327         dm[0].dm_startblk = 0;
 328         dm[0].dm_startbit = ADFS_DR_SIZE_BITS;
 329         dm[i].dm_endbit   = (le32_to_cpu(dr->disc_size_high) << (32 - dr->log2bpmb)) +
 330                             (le32_to_cpu(dr->disc_size) >> dr->log2bpmb) +
 331                             (ADFS_DR_SIZE_BITS - i * zone_size);
 332
 333         if (adfs_checkmap(sb, dm))
 334                 return dm;
 335
 336         adfs_error(sb, "map corrupted");
 337
 338 error_free:
 339         while (--zone >= 0)
 340                 brelse(dm[zone].dm_bh);
 341
 342         kfree(dm);
 343         return NULL;
 344 }
 345
 346 static inline unsigned long adfs_discsize(struct adfs_discrecord *dr, int block_bits)
 347 {
 348         unsigned long discsize;
 349
 350         discsize  = le32_to_cpu(dr->disc_size_high) << (32 - block_bits);
 351         discsize |= le32_to_cpu(dr->disc_size) >> block_bits;
 352
 353         return discsize;
 354 }
 355
 356 static int adfs_fill_super(struct super_block *sb, void *data, int silent)
 357 {
 358         struct adfs_discrecord *dr;
 359         struct buffer_head *bh;
 360         struct object_info root_obj;
 361         unsigned char *b_data;
 362         struct adfs_sb_info *asb;
 363         struct inode *root;
 364
 365         sb->s_flags |= MS_NODIRATIME;
 366
 367         asb = kzalloc(sizeof(*asb), GFP_KERNEL);
 368         if (!asb)
 369                 return -ENOMEM;
 370         sb->s_fs_info = asb;
 371
 372         /* set default options */
 373         asb->s_uid = 0;
 374         asb->s_gid = 0;
 375         asb->s_owner_mask = ADFS_DEFAULT_OWNER_MASK;
 376         asb->s_other_mask = ADFS_DEFAULT_OTHER_MASK;
 377         asb->s_ftsuffix = 0;
 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         /* Set root object date as 01 Jan 1987 00:00:00 */
 458         root_obj.loadaddr  = 0xfff0003f;
 459         root_obj.execaddr  = 0xec22c000;
 460         root_obj.size      = ADFS_NEWDIR_SIZE;
 461         root_obj.attr      = ADFS_NDA_DIRECTORY   | ADFS_NDA_OWNER_READ |
 462                              ADFS_NDA_OWNER_WRITE | ADFS_NDA_PUBLIC_READ;
 463         root_obj.filetype  = -1;
 464
 465         /*
 466          * If this is a F+ disk with variable length directories,
 467          * get the root_size from the disc record.
 468          */
 469         if (asb->s_version) {
 470                 root_obj.size = le32_to_cpu(dr->root_size);
 471                 asb->s_dir     = &adfs_fplus_dir_ops;
 472                 asb->s_namelen = ADFS_FPLUS_NAME_LEN;
 473         } else {
 474                 asb->s_dir     = &adfs_f_dir_ops;
 475                 asb->s_namelen = ADFS_F_NAME_LEN;
 476         }
 477         /*
 478          * ,xyz hex filetype suffix may be added by driver
 479          * to files that have valid RISC OS filetype
 480          */
 481         if (asb->s_ftsuffix)
 482                 asb->s_namelen += 4;
 483
 484         sb->s_d_op = &adfs_dentry_operations;
 485         root = adfs_iget(sb, &root_obj);
 486         sb->s_root = d_alloc_root(root);
 487         if (!sb->s_root) {
 488                 int i;
 489                 iput(root);
 490                 for (i = 0; i < asb->s_map_size; i++)
 491                         brelse(asb->s_map[i].dm_bh);
 492                 kfree(asb->s_map);
 493                 adfs_error(sb, "get root inode failed\n");
 494                 goto error;
 495         }
 496         return 0;
 497
 498 error_free_bh:
 499         brelse(bh);
 500 error:
 501         sb->s_fs_info = NULL;
 502         kfree(asb);
 503         return -EINVAL;
 504 }
 505
 506 static struct dentry *adfs_mount(struct file_system_type *fs_type,
 507         int flags, const char *dev_name, void *data)
 508 {
 509         return mount_bdev(fs_type, flags, dev_name, data, adfs_fill_super);
 510 }
 511
 512 static struct file_system_type adfs_fs_type = {
 513         .owner          = THIS_MODULE,
 514         .name           = "adfs",
 515         .mount          = adfs_mount,
 516         .kill_sb        = kill_block_super,
 517         .fs_flags       = FS_REQUIRES_DEV,
 518 };
 519
 520 static int __init init_adfs_fs(void)
 521 {
 522         int err = init_inodecache();
 523         if (err)
 524                 goto out1;
 525         err = register_filesystem(&adfs_fs_type);
 526         if (err)
 527                 goto out;
 528         return 0;
 529 out:
 530         destroy_inodecache();
 531 out1:
 532         return err;
 533 }
 534
 535 static void __exit exit_adfs_fs(void)
 536 {
 537         unregister_filesystem(&adfs_fs_type);
 538         destroy_inodecache();
 539 }
 540
 541 module_init(init_adfs_fs)
 542 module_exit(exit_adfs_fs)
 543 MODULE_LICENSE("GPL");