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 <linux/user_namespace.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         for (i = 0; i < asb->s_map_size; i++)
 124                 brelse(asb->s_map[i].dm_bh);
 125         kfree(asb->s_map);
 126         kfree_rcu(asb, rcu);
 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 (!uid_eq(asb->s_uid, GLOBAL_ROOT_UID))
 134                 seq_printf(seq, ",uid=%u", from_kuid_munged(&init_user_ns, asb->s_uid));
 135         if (!gid_eq(asb->s_gid, GLOBAL_ROOT_GID))
 136                 seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, 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 = make_kuid(current_user_ns(), option);
 179                         if (!uid_valid(asb->s_uid))
 180                                 return -EINVAL;
 181                         break;
 182                 case Opt_gid:
 183                         if (match_int(args, &option))
 184                                 return -EINVAL;
 185                         asb->s_gid = make_kgid(current_user_ns(), option);
 186                         if (!gid_valid(asb->s_gid))
 187                                 return -EINVAL;
 188                         break;
 189                 case Opt_ownmask:
 190                         if (match_octal(args, &option))
 191                                 return -EINVAL;
 192                         asb->s_owner_mask = option;
 193                         break;
 194                 case Opt_othmask:
 195                         if (match_octal(args, &option))
 196                                 return -EINVAL;
 197                         asb->s_other_mask = option;
 198                         break;
 199                 case Opt_ftsuffix:
 200                         if (match_int(args, &option))
 201                                 return -EINVAL;
 202                         asb->s_ftsuffix = option;
 203                         break;
 204                 default:
 205                         printk("ADFS-fs: unrecognised mount option \"%s\" "
 206                                         "or missing value\n", p);
 207                         return -EINVAL;
 208                 }
 209         }
 210         return 0;
 211 }
 212
 213 static int adfs_remount(struct super_block *sb, int *flags, char *data)
 214 {
 215         sync_filesystem(sb);
 216         *flags |= MS_NODIRATIME;
 217         return parse_options(sb, data);
 218 }
 219
 220 static int adfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 221 {
 222         struct super_block *sb = dentry->d_sb;
 223         struct adfs_sb_info *sbi = ADFS_SB(sb);
 224         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 225
 226         buf->f_type    = ADFS_SUPER_MAGIC;
 227         buf->f_namelen = sbi->s_namelen;
 228         buf->f_bsize   = sb->s_blocksize;
 229         buf->f_blocks  = sbi->s_size;
 230         buf->f_files   = sbi->s_ids_per_zone * sbi->s_map_size;
 231         buf->f_bavail  =
 232         buf->f_bfree   = adfs_map_free(sb);
 233         buf->f_ffree   = (long)(buf->f_bfree * buf->f_files) / (long)buf->f_blocks;
 234         buf->f_fsid.val[0] = (u32)id;
 235         buf->f_fsid.val[1] = (u32)(id >> 32);
 236
 237         return 0;
 238 }
 239
 240 static struct kmem_cache *adfs_inode_cachep;
 241
 242 static struct inode *adfs_alloc_inode(struct super_block *sb)
 243 {
 244         struct adfs_inode_info *ei;
 245         ei = kmem_cache_alloc(adfs_inode_cachep, GFP_KERNEL);
 246         if (!ei)
 247                 return NULL;
 248         return &ei->vfs_inode;
 249 }
 250
 251 static void adfs_i_callback(struct rcu_head *head)
 252 {
 253         struct inode *inode = container_of(head, struct inode, i_rcu);
 254         kmem_cache_free(adfs_inode_cachep, ADFS_I(inode));
 255 }
 256
 257 static void adfs_destroy_inode(struct inode *inode)
 258 {
 259         call_rcu(&inode->i_rcu, adfs_i_callback);
 260 }
 261
 262 static void init_once(void *foo)
 263 {
 264         struct adfs_inode_info *ei = (struct adfs_inode_info *) foo;
 265
 266         inode_init_once(&ei->vfs_inode);
 267 }
 268
 269 static int __init init_inodecache(void)
 270 {
 271         adfs_inode_cachep = kmem_cache_create("adfs_inode_cache",
 272                                              sizeof(struct adfs_inode_info),
 273                                              0, (SLAB_RECLAIM_ACCOUNT|
 274                                                 SLAB_MEM_SPREAD|SLAB_ACCOUNT),
 275                                              init_once);
 276         if (adfs_inode_cachep == NULL)
 277                 return -ENOMEM;
 278         return 0;
 279 }
 280
 281 static void destroy_inodecache(void)
 282 {
 283         /*
 284          * Make sure all delayed rcu free inodes are flushed before we
 285          * destroy cache.
 286          */
 287         rcu_barrier();
 288         kmem_cache_destroy(adfs_inode_cachep);
 289 }
 290
 291 static const struct super_operations adfs_sops = {
 292         .alloc_inode    = adfs_alloc_inode,
 293         .destroy_inode  = adfs_destroy_inode,
 294         .write_inode    = adfs_write_inode,
 295         .put_super      = adfs_put_super,
 296         .statfs         = adfs_statfs,
 297         .remount_fs     = adfs_remount,
 298         .show_options   = adfs_show_options,
 299 };
 300
 301 static struct adfs_discmap *adfs_read_map(struct super_block *sb, struct adfs_discrecord *dr)
 302 {
 303         struct adfs_discmap *dm;
 304         unsigned int map_addr, zone_size, nzones;
 305         int i, zone;
 306         struct adfs_sb_info *asb = ADFS_SB(sb);
 307
 308         nzones    = asb->s_map_size;
 309         zone_size = (8 << dr->log2secsize) - le16_to_cpu(dr->zone_spare);
 310         map_addr  = (nzones >> 1) * zone_size -
 311                      ((nzones > 1) ? ADFS_DR_SIZE_BITS : 0);
 312         map_addr  = signed_asl(map_addr, asb->s_map2blk);
 313
 314         asb->s_ids_per_zone = zone_size / (asb->s_idlen + 1);
 315
 316         dm = kmalloc(nzones * sizeof(*dm), GFP_KERNEL);
 317         if (dm == NULL) {
 318                 adfs_error(sb, "not enough memory");
 319                 return ERR_PTR(-ENOMEM);
 320         }
 321
 322         for (zone = 0; zone < nzones; zone++, map_addr++) {
 323                 dm[zone].dm_startbit = 0;
 324                 dm[zone].dm_endbit   = zone_size;
 325                 dm[zone].dm_startblk = zone * zone_size - ADFS_DR_SIZE_BITS;
 326                 dm[zone].dm_bh       = sb_bread(sb, map_addr);
 327
 328                 if (!dm[zone].dm_bh) {
 329                         adfs_error(sb, "unable to read map");
 330                         goto error_free;
 331                 }
 332         }
 333
 334         /* adjust the limits for the first and last map zones */
 335         i = zone - 1;
 336         dm[0].dm_startblk = 0;
 337         dm[0].dm_startbit = ADFS_DR_SIZE_BITS;
 338         dm[i].dm_endbit   = (le32_to_cpu(dr->disc_size_high) << (32 - dr->log2bpmb)) +
 339                             (le32_to_cpu(dr->disc_size) >> dr->log2bpmb) +
 340                             (ADFS_DR_SIZE_BITS - i * zone_size);
 341
 342         if (adfs_checkmap(sb, dm))
 343                 return dm;
 344
 345         adfs_error(sb, "map corrupted");
 346
 347 error_free:
 348         while (--zone >= 0)
 349                 brelse(dm[zone].dm_bh);
 350
 351         kfree(dm);
 352         return ERR_PTR(-EIO);
 353 }
 354
 355 static inline unsigned long adfs_discsize(struct adfs_discrecord *dr, int block_bits)
 356 {
 357         unsigned long discsize;
 358
 359         discsize  = le32_to_cpu(dr->disc_size_high) << (32 - block_bits);
 360         discsize |= le32_to_cpu(dr->disc_size) >> block_bits;
 361
 362         return discsize;
 363 }
 364
 365 static int adfs_fill_super(struct super_block *sb, void *data, int silent)
 366 {
 367         struct adfs_discrecord *dr;
 368         struct buffer_head *bh;
 369         struct object_info root_obj;
 370         unsigned char *b_data;
 371         struct adfs_sb_info *asb;
 372         struct inode *root;
 373         int ret = -EINVAL;
 374
 375         sb->s_flags |= MS_NODIRATIME;
 376
 377         asb = kzalloc(sizeof(*asb), GFP_KERNEL);
 378         if (!asb)
 379                 return -ENOMEM;
 380         sb->s_fs_info = asb;
 381
 382         /* set default options */
 383         asb->s_uid = GLOBAL_ROOT_UID;
 384         asb->s_gid = GLOBAL_ROOT_GID;
 385         asb->s_owner_mask = ADFS_DEFAULT_OWNER_MASK;
 386         asb->s_other_mask = ADFS_DEFAULT_OTHER_MASK;
 387         asb->s_ftsuffix = 0;
 388
 389         if (parse_options(sb, data))
 390                 goto error;
 391
 392         sb_set_blocksize(sb, BLOCK_SIZE);
 393         if (!(bh = sb_bread(sb, ADFS_DISCRECORD / BLOCK_SIZE))) {
 394                 adfs_error(sb, "unable to read superblock");
 395                 ret = -EIO;
 396                 goto error;
 397         }
 398
 399         b_data = bh->b_data + (ADFS_DISCRECORD % BLOCK_SIZE);
 400
 401         if (adfs_checkbblk(b_data)) {
 402                 if (!silent)
 403                         printk("VFS: Can't find an adfs filesystem on dev "
 404                                 "%s.\n", sb->s_id);
 405                 ret = -EINVAL;
 406                 goto error_free_bh;
 407         }
 408
 409         dr = (struct adfs_discrecord *)(b_data + ADFS_DR_OFFSET);
 410
 411         /*
 412          * Do some sanity checks on the ADFS disc record
 413          */
 414         if (adfs_checkdiscrecord(dr)) {
 415                 if (!silent)
 416                         printk("VPS: Can't find an adfs filesystem on dev "
 417                                 "%s.\n", sb->s_id);
 418                 ret = -EINVAL;
 419                 goto error_free_bh;
 420         }
 421
 422         brelse(bh);
 423         if (sb_set_blocksize(sb, 1 << dr->log2secsize)) {
 424                 bh = sb_bread(sb, ADFS_DISCRECORD / sb->s_blocksize);
 425                 if (!bh) {
 426                         adfs_error(sb, "couldn't read superblock on "
 427                                 "2nd try.");
 428                         ret = -EIO;
 429                         goto error;
 430                 }
 431                 b_data = bh->b_data + (ADFS_DISCRECORD % sb->s_blocksize);
 432                 if (adfs_checkbblk(b_data)) {
 433                         adfs_error(sb, "disc record mismatch, very weird!");
 434                         ret = -EINVAL;
 435                         goto error_free_bh;
 436                 }
 437                 dr = (struct adfs_discrecord *)(b_data + ADFS_DR_OFFSET);
 438         } else {
 439                 if (!silent)
 440                         printk(KERN_ERR "VFS: Unsupported blocksize on dev "
 441                                 "%s.\n", sb->s_id);
 442                 ret = -EINVAL;
 443                 goto error;
 444         }
 445
 446         /*
 447          * blocksize on this device should now be set to the ADFS log2secsize
 448          */
 449
 450         sb->s_magic             = ADFS_SUPER_MAGIC;
 451         asb->s_idlen            = dr->idlen;
 452         asb->s_map_size         = dr->nzones | (dr->nzones_high << 8);
 453         asb->s_map2blk          = dr->log2bpmb - dr->log2secsize;
 454         asb->s_size             = adfs_discsize(dr, sb->s_blocksize_bits);
 455         asb->s_version          = dr->format_version;
 456         asb->s_log2sharesize    = dr->log2sharesize;
 457
 458         asb->s_map = adfs_read_map(sb, dr);
 459         if (IS_ERR(asb->s_map)) {
 460                 ret =  PTR_ERR(asb->s_map);
 461                 goto error_free_bh;
 462         }
 463
 464         brelse(bh);
 465
 466         /*
 467          * set up enough so that we can read an inode
 468          */
 469         sb->s_op = &adfs_sops;
 470
 471         dr = (struct adfs_discrecord *)(asb->s_map[0].dm_bh->b_data + 4);
 472
 473         root_obj.parent_id = root_obj.file_id = le32_to_cpu(dr->root);
 474         root_obj.name_len  = 0;
 475         /* Set root object date as 01 Jan 1987 00:00:00 */
 476         root_obj.loadaddr  = 0xfff0003f;
 477         root_obj.execaddr  = 0xec22c000;
 478         root_obj.size      = ADFS_NEWDIR_SIZE;
 479         root_obj.attr      = ADFS_NDA_DIRECTORY   | ADFS_NDA_OWNER_READ |
 480                              ADFS_NDA_OWNER_WRITE | ADFS_NDA_PUBLIC_READ;
 481         root_obj.filetype  = -1;
 482
 483         /*
 484          * If this is a F+ disk with variable length directories,
 485          * get the root_size from the disc record.
 486          */
 487         if (asb->s_version) {
 488                 root_obj.size = le32_to_cpu(dr->root_size);
 489                 asb->s_dir     = &adfs_fplus_dir_ops;
 490                 asb->s_namelen = ADFS_FPLUS_NAME_LEN;
 491         } else {
 492                 asb->s_dir     = &adfs_f_dir_ops;
 493                 asb->s_namelen = ADFS_F_NAME_LEN;
 494         }
 495         /*
 496          * ,xyz hex filetype suffix may be added by driver
 497          * to files that have valid RISC OS filetype
 498          */
 499         if (asb->s_ftsuffix)
 500                 asb->s_namelen += 4;
 501
 502         sb->s_d_op = &adfs_dentry_operations;
 503         root = adfs_iget(sb, &root_obj);
 504         sb->s_root = d_make_root(root);
 505         if (!sb->s_root) {
 506                 int i;
 507                 for (i = 0; i < asb->s_map_size; i++)
 508                         brelse(asb->s_map[i].dm_bh);
 509                 kfree(asb->s_map);
 510                 adfs_error(sb, "get root inode failed\n");
 511                 ret = -EIO;
 512                 goto error;
 513         }
 514         return 0;
 515
 516 error_free_bh:
 517         brelse(bh);
 518 error:
 519         sb->s_fs_info = NULL;
 520         kfree(asb);
 521         return ret;
 522 }
 523
 524 static struct dentry *adfs_mount(struct file_system_type *fs_type,
 525         int flags, const char *dev_name, void *data)
 526 {
 527         return mount_bdev(fs_type, flags, dev_name, data, adfs_fill_super);
 528 }
 529
 530 static struct file_system_type adfs_fs_type = {
 531         .owner          = THIS_MODULE,
 532         .name           = "adfs",
 533         .mount          = adfs_mount,
 534         .kill_sb        = kill_block_super,
 535         .fs_flags       = FS_REQUIRES_DEV,
 536 };
 537 MODULE_ALIAS_FS("adfs");
 538
 539 static int __init init_adfs_fs(void)
 540 {
 541         int err = init_inodecache();
 542         if (err)
 543                 goto out1;
 544         err = register_filesystem(&adfs_fs_type);
 545         if (err)
 546                 goto out;
 547         return 0;
 548 out:
 549         destroy_inodecache();
 550 out1:
 551         return err;
 552 }
 553
 554 static void __exit exit_adfs_fs(void)
 555 {
 556         unregister_filesystem(&adfs_fs_type);
 557         destroy_inodecache();
 558 }
 559
 560 module_init(init_adfs_fs)
 561 module_exit(exit_adfs_fs)
 562 MODULE_LICENSE("GPL");