linux/fs/adfs/super.c
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   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
  26void __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
  40static 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
  73static 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
  97static 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
 118static 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(asb);
 127        sb->s_fs_info = NULL;
 128}
 129
 130static int adfs_show_options(struct seq_file *seq, struct dentry *root)
 131{
 132        struct adfs_sb_info *asb = ADFS_SB(root->d_sb);
 133
 134        if (!uid_eq(asb->s_uid, GLOBAL_ROOT_UID))
 135                seq_printf(seq, ",uid=%u", from_kuid_munged(&init_user_ns, asb->s_uid));
 136        if (!gid_eq(asb->s_gid, GLOBAL_ROOT_GID))
 137                seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, asb->s_gid));
 138        if (asb->s_owner_mask != ADFS_DEFAULT_OWNER_MASK)
 139                seq_printf(seq, ",ownmask=%o", asb->s_owner_mask);
 140        if (asb->s_other_mask != ADFS_DEFAULT_OTHER_MASK)
 141                seq_printf(seq, ",othmask=%o", asb->s_other_mask);
 142        if (asb->s_ftsuffix != 0)
 143                seq_printf(seq, ",ftsuffix=%u", asb->s_ftsuffix);
 144
 145        return 0;
 146}
 147
 148enum {Opt_uid, Opt_gid, Opt_ownmask, Opt_othmask, Opt_ftsuffix, Opt_err};
 149
 150static const match_table_t tokens = {
 151        {Opt_uid, "uid=%u"},
 152        {Opt_gid, "gid=%u"},
 153        {Opt_ownmask, "ownmask=%o"},
 154        {Opt_othmask, "othmask=%o"},
 155        {Opt_ftsuffix, "ftsuffix=%u"},
 156        {Opt_err, NULL}
 157};
 158
 159static int parse_options(struct super_block *sb, char *options)
 160{
 161        char *p;
 162        struct adfs_sb_info *asb = ADFS_SB(sb);
 163        int option;
 164
 165        if (!options)
 166                return 0;
 167
 168        while ((p = strsep(&options, ",")) != NULL) {
 169                substring_t args[MAX_OPT_ARGS];
 170                int token;
 171                if (!*p)
 172                        continue;
 173
 174                token = match_token(p, tokens, args);
 175                switch (token) {
 176                case Opt_uid:
 177                        if (match_int(args, &option))
 178                                return -EINVAL;
 179                        asb->s_uid = make_kuid(current_user_ns(), option);
 180                        if (!uid_valid(asb->s_uid))
 181                                return -EINVAL;
 182                        break;
 183                case Opt_gid:
 184                        if (match_int(args, &option))
 185                                return -EINVAL;
 186                        asb->s_gid = make_kgid(current_user_ns(), option);
 187                        if (!gid_valid(asb->s_gid))
 188                                return -EINVAL;
 189                        break;
 190                case Opt_ownmask:
 191                        if (match_octal(args, &option))
 192                                return -EINVAL;
 193                        asb->s_owner_mask = option;
 194                        break;
 195                case Opt_othmask:
 196                        if (match_octal(args, &option))
 197                                return -EINVAL;
 198                        asb->s_other_mask = option;
 199                        break;
 200                case Opt_ftsuffix:
 201                        if (match_int(args, &option))
 202                                return -EINVAL;
 203                        asb->s_ftsuffix = option;
 204                        break;
 205                default:
 206                        printk("ADFS-fs: unrecognised mount option \"%s\" "
 207                                        "or missing value\n", p);
 208                        return -EINVAL;
 209                }
 210        }
 211        return 0;
 212}
 213
 214static int adfs_remount(struct super_block *sb, int *flags, char *data)
 215{
 216        *flags |= MS_NODIRATIME;
 217        return parse_options(sb, data);
 218}
 219
 220static 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
 240static struct kmem_cache *adfs_inode_cachep;
 241
 242static struct inode *adfs_alloc_inode(struct super_block *sb)
 243{
 244        struct adfs_inode_info *ei;
 245        ei = (struct adfs_inode_info *)kmem_cache_alloc(adfs_inode_cachep, GFP_KERNEL);
 246        if (!ei)
 247                return NULL;
 248        return &ei->vfs_inode;
 249}
 250
 251static 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
 257static void adfs_destroy_inode(struct inode *inode)
 258{
 259        call_rcu(&inode->i_rcu, adfs_i_callback);
 260}
 261
 262static 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
 269static int 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),
 275                                             init_once);
 276        if (adfs_inode_cachep == NULL)
 277                return -ENOMEM;
 278        return 0;
 279}
 280
 281static 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
 291static 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
 301static 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 NULL;
 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
 347error_free:
 348        while (--zone >= 0)
 349                brelse(dm[zone].dm_bh);
 350
 351        kfree(dm);
 352        return NULL;
 353}
 354
 355static 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
 365static 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
 374        sb->s_flags |= MS_NODIRATIME;
 375
 376        asb = kzalloc(sizeof(*asb), GFP_KERNEL);
 377        if (!asb)
 378                return -ENOMEM;
 379        sb->s_fs_info = asb;
 380
 381        /* set default options */
 382        asb->s_uid = GLOBAL_ROOT_UID;
 383        asb->s_gid = GLOBAL_ROOT_GID;
 384        asb->s_owner_mask = ADFS_DEFAULT_OWNER_MASK;
 385        asb->s_other_mask = ADFS_DEFAULT_OTHER_MASK;
 386        asb->s_ftsuffix = 0;
 387
 388        if (parse_options(sb, data))
 389                goto error;
 390
 391        sb_set_blocksize(sb, BLOCK_SIZE);
 392        if (!(bh = sb_bread(sb, ADFS_DISCRECORD / BLOCK_SIZE))) {
 393                adfs_error(sb, "unable to read superblock");
 394                goto error;
 395        }
 396
 397        b_data = bh->b_data + (ADFS_DISCRECORD % BLOCK_SIZE);
 398
 399        if (adfs_checkbblk(b_data)) {
 400                if (!silent)
 401                        printk("VFS: Can't find an adfs filesystem on dev "
 402                                "%s.\n", sb->s_id);
 403                goto error_free_bh;
 404        }
 405
 406        dr = (struct adfs_discrecord *)(b_data + ADFS_DR_OFFSET);
 407
 408        /*
 409         * Do some sanity checks on the ADFS disc record
 410         */
 411        if (adfs_checkdiscrecord(dr)) {
 412                if (!silent)
 413                        printk("VPS: Can't find an adfs filesystem on dev "
 414                                "%s.\n", sb->s_id);
 415                goto error_free_bh;
 416        }
 417
 418        brelse(bh);
 419        if (sb_set_blocksize(sb, 1 << dr->log2secsize)) {
 420                bh = sb_bread(sb, ADFS_DISCRECORD / sb->s_blocksize);
 421                if (!bh) {
 422                        adfs_error(sb, "couldn't read superblock on "
 423                                "2nd try.");
 424                        goto error;
 425                }
 426                b_data = bh->b_data + (ADFS_DISCRECORD % sb->s_blocksize);
 427                if (adfs_checkbblk(b_data)) {
 428                        adfs_error(sb, "disc record mismatch, very weird!");
 429                        goto error_free_bh;
 430                }
 431                dr = (struct adfs_discrecord *)(b_data + ADFS_DR_OFFSET);
 432        } else {
 433                if (!silent)
 434                        printk(KERN_ERR "VFS: Unsupported blocksize on dev "
 435                                "%s.\n", sb->s_id);
 436                goto error;
 437        }
 438
 439        /*
 440         * blocksize on this device should now be set to the ADFS log2secsize
 441         */
 442
 443        sb->s_magic             = ADFS_SUPER_MAGIC;
 444        asb->s_idlen            = dr->idlen;
 445        asb->s_map_size         = dr->nzones | (dr->nzones_high << 8);
 446        asb->s_map2blk          = dr->log2bpmb - dr->log2secsize;
 447        asb->s_size             = adfs_discsize(dr, sb->s_blocksize_bits);
 448        asb->s_version          = dr->format_version;
 449        asb->s_log2sharesize    = dr->log2sharesize;
 450        
 451        asb->s_map = adfs_read_map(sb, dr);
 452        if (!asb->s_map)
 453                goto error_free_bh;
 454
 455        brelse(bh);
 456
 457        /*
 458         * set up enough so that we can read an inode
 459         */
 460        sb->s_op = &adfs_sops;
 461
 462        dr = (struct adfs_discrecord *)(asb->s_map[0].dm_bh->b_data + 4);
 463
 464        root_obj.parent_id = root_obj.file_id = le32_to_cpu(dr->root);
 465        root_obj.name_len  = 0;
 466        /* Set root object date as 01 Jan 1987 00:00:00 */
 467        root_obj.loadaddr  = 0xfff0003f;
 468        root_obj.execaddr  = 0xec22c000;
 469        root_obj.size      = ADFS_NEWDIR_SIZE;
 470        root_obj.attr      = ADFS_NDA_DIRECTORY   | ADFS_NDA_OWNER_READ |
 471                             ADFS_NDA_OWNER_WRITE | ADFS_NDA_PUBLIC_READ;
 472        root_obj.filetype  = -1;
 473
 474        /*
 475         * If this is a F+ disk with variable length directories,
 476         * get the root_size from the disc record.
 477         */
 478        if (asb->s_version) {
 479                root_obj.size = le32_to_cpu(dr->root_size);
 480                asb->s_dir     = &adfs_fplus_dir_ops;
 481                asb->s_namelen = ADFS_FPLUS_NAME_LEN;
 482        } else {
 483                asb->s_dir     = &adfs_f_dir_ops;
 484                asb->s_namelen = ADFS_F_NAME_LEN;
 485        }
 486        /*
 487         * ,xyz hex filetype suffix may be added by driver
 488         * to files that have valid RISC OS filetype
 489         */
 490        if (asb->s_ftsuffix)
 491                asb->s_namelen += 4;
 492
 493        sb->s_d_op = &adfs_dentry_operations;
 494        root = adfs_iget(sb, &root_obj);
 495        sb->s_root = d_make_root(root);
 496        if (!sb->s_root) {
 497                int i;
 498                for (i = 0; i < asb->s_map_size; i++)
 499                        brelse(asb->s_map[i].dm_bh);
 500                kfree(asb->s_map);
 501                adfs_error(sb, "get root inode failed\n");
 502                goto error;
 503        }
 504        return 0;
 505
 506error_free_bh:
 507        brelse(bh);
 508error:
 509        sb->s_fs_info = NULL;
 510        kfree(asb);
 511        return -EINVAL;
 512}
 513
 514static struct dentry *adfs_mount(struct file_system_type *fs_type,
 515        int flags, const char *dev_name, void *data)
 516{
 517        return mount_bdev(fs_type, flags, dev_name, data, adfs_fill_super);
 518}
 519
 520static struct file_system_type adfs_fs_type = {
 521        .owner          = THIS_MODULE,
 522        .name           = "adfs",
 523        .mount          = adfs_mount,
 524        .kill_sb        = kill_block_super,
 525        .fs_flags       = FS_REQUIRES_DEV,
 526};
 527
 528static 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;
 537out:
 538        destroy_inodecache();
 539out1:
 540        return err;
 541}
 542
 543static void __exit exit_adfs_fs(void)
 544{
 545        unregister_filesystem(&adfs_fs_type);
 546        destroy_inodecache();
 547}
 548
 549module_init(init_adfs_fs)
 550module_exit(exit_adfs_fs)
 551MODULE_LICENSE("GPL");
 552
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