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