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/smp_lock.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
  25void __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
  39static 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
  72static 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
  96static 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
 117static void adfs_put_super(struct super_block *sb)
 118{
 119        int i;
 120        struct adfs_sb_info *asb = ADFS_SB(sb);
 121
 122        lock_kernel();
 123
 124        for (i = 0; i < asb->s_map_size; i++)
 125                brelse(asb->s_map[i].dm_bh);
 126        kfree(asb->s_map);
 127        kfree(asb);
 128        sb->s_fs_info = NULL;
 129
 130        unlock_kernel();
 131}
 132
 133static int adfs_show_options(struct seq_file *seq, struct vfsmount *mnt)
 134{
 135        struct adfs_sb_info *asb = ADFS_SB(mnt->mnt_sb);
 136
 137        if (asb->s_uid != 0)
 138                seq_printf(seq, ",uid=%u", asb->s_uid);
 139        if (asb->s_gid != 0)
 140                seq_printf(seq, ",gid=%u", asb->s_gid);
 141        if (asb->s_owner_mask != ADFS_DEFAULT_OWNER_MASK)
 142                seq_printf(seq, ",ownmask=%o", asb->s_owner_mask);
 143        if (asb->s_other_mask != ADFS_DEFAULT_OTHER_MASK)
 144                seq_printf(seq, ",othmask=%o", asb->s_other_mask);
 145
 146        return 0;
 147}
 148
 149enum {Opt_uid, Opt_gid, Opt_ownmask, Opt_othmask, Opt_err};
 150
 151static const match_table_t tokens = {
 152        {Opt_uid, "uid=%u"},
 153        {Opt_gid, "gid=%u"},
 154        {Opt_ownmask, "ownmask=%o"},
 155        {Opt_othmask, "othmask=%o"},
 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 = option;
 180                        break;
 181                case Opt_gid:
 182                        if (match_int(args, &option))
 183                                return -EINVAL;
 184                        asb->s_gid = option;
 185                        break;
 186                case Opt_ownmask:
 187                        if (match_octal(args, &option))
 188                                return -EINVAL;
 189                        asb->s_owner_mask = option;
 190                        break;
 191                case Opt_othmask:
 192                        if (match_octal(args, &option))
 193                                return -EINVAL;
 194                        asb->s_other_mask = option;
 195                        break;
 196                default:
 197                        printk("ADFS-fs: unrecognised mount option \"%s\" "
 198                                        "or missing value\n", p);
 199                        return -EINVAL;
 200                }
 201        }
 202        return 0;
 203}
 204
 205static int adfs_remount(struct super_block *sb, int *flags, char *data)
 206{
 207        *flags |= MS_NODIRATIME;
 208        return parse_options(sb, data);
 209}
 210
 211static int adfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 212{
 213        struct super_block *sb = dentry->d_sb;
 214        struct adfs_sb_info *sbi = ADFS_SB(sb);
 215        u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 216
 217        buf->f_type    = ADFS_SUPER_MAGIC;
 218        buf->f_namelen = sbi->s_namelen;
 219        buf->f_bsize   = sb->s_blocksize;
 220        buf->f_blocks  = sbi->s_size;
 221        buf->f_files   = sbi->s_ids_per_zone * sbi->s_map_size;
 222        buf->f_bavail  =
 223        buf->f_bfree   = adfs_map_free(sb);
 224        buf->f_ffree   = (long)(buf->f_bfree * buf->f_files) / (long)buf->f_blocks;
 225        buf->f_fsid.val[0] = (u32)id;
 226        buf->f_fsid.val[1] = (u32)(id >> 32);
 227
 228        return 0;
 229}
 230
 231static struct kmem_cache *adfs_inode_cachep;
 232
 233static struct inode *adfs_alloc_inode(struct super_block *sb)
 234{
 235        struct adfs_inode_info *ei;
 236        ei = (struct adfs_inode_info *)kmem_cache_alloc(adfs_inode_cachep, GFP_KERNEL);
 237        if (!ei)
 238                return NULL;
 239        return &ei->vfs_inode;
 240}
 241
 242static void adfs_destroy_inode(struct inode *inode)
 243{
 244        kmem_cache_free(adfs_inode_cachep, ADFS_I(inode));
 245}
 246
 247static void init_once(void *foo)
 248{
 249        struct adfs_inode_info *ei = (struct adfs_inode_info *) foo;
 250
 251        inode_init_once(&ei->vfs_inode);
 252}
 253
 254static int init_inodecache(void)
 255{
 256        adfs_inode_cachep = kmem_cache_create("adfs_inode_cache",
 257                                             sizeof(struct adfs_inode_info),
 258                                             0, (SLAB_RECLAIM_ACCOUNT|
 259                                                SLAB_MEM_SPREAD),
 260                                             init_once);
 261        if (adfs_inode_cachep == NULL)
 262                return -ENOMEM;
 263        return 0;
 264}
 265
 266static void destroy_inodecache(void)
 267{
 268        kmem_cache_destroy(adfs_inode_cachep);
 269}
 270
 271static const struct super_operations adfs_sops = {
 272        .alloc_inode    = adfs_alloc_inode,
 273        .destroy_inode  = adfs_destroy_inode,
 274        .write_inode    = adfs_write_inode,
 275        .put_super      = adfs_put_super,
 276        .statfs         = adfs_statfs,
 277        .remount_fs     = adfs_remount,
 278        .show_options   = adfs_show_options,
 279};
 280
 281static struct adfs_discmap *adfs_read_map(struct super_block *sb, struct adfs_discrecord *dr)
 282{
 283        struct adfs_discmap *dm;
 284        unsigned int map_addr, zone_size, nzones;
 285        int i, zone;
 286        struct adfs_sb_info *asb = ADFS_SB(sb);
 287
 288        nzones    = asb->s_map_size;
 289        zone_size = (8 << dr->log2secsize) - le16_to_cpu(dr->zone_spare);
 290        map_addr  = (nzones >> 1) * zone_size -
 291                     ((nzones > 1) ? ADFS_DR_SIZE_BITS : 0);
 292        map_addr  = signed_asl(map_addr, asb->s_map2blk);
 293
 294        asb->s_ids_per_zone = zone_size / (asb->s_idlen + 1);
 295
 296        dm = kmalloc(nzones * sizeof(*dm), GFP_KERNEL);
 297        if (dm == NULL) {
 298                adfs_error(sb, "not enough memory");
 299                return NULL;
 300        }
 301
 302        for (zone = 0; zone < nzones; zone++, map_addr++) {
 303                dm[zone].dm_startbit = 0;
 304                dm[zone].dm_endbit   = zone_size;
 305                dm[zone].dm_startblk = zone * zone_size - ADFS_DR_SIZE_BITS;
 306                dm[zone].dm_bh       = sb_bread(sb, map_addr);
 307
 308                if (!dm[zone].dm_bh) {
 309                        adfs_error(sb, "unable to read map");
 310                        goto error_free;
 311                }
 312        }
 313
 314        /* adjust the limits for the first and last map zones */
 315        i = zone - 1;
 316        dm[0].dm_startblk = 0;
 317        dm[0].dm_startbit = ADFS_DR_SIZE_BITS;
 318        dm[i].dm_endbit   = (le32_to_cpu(dr->disc_size_high) << (32 - dr->log2bpmb)) +
 319                            (le32_to_cpu(dr->disc_size) >> dr->log2bpmb) +
 320                            (ADFS_DR_SIZE_BITS - i * zone_size);
 321
 322        if (adfs_checkmap(sb, dm))
 323                return dm;
 324
 325        adfs_error(sb, "map corrupted");
 326
 327error_free:
 328        while (--zone >= 0)
 329                brelse(dm[zone].dm_bh);
 330
 331        kfree(dm);
 332        return NULL;
 333}
 334
 335static inline unsigned long adfs_discsize(struct adfs_discrecord *dr, int block_bits)
 336{
 337        unsigned long discsize;
 338
 339        discsize  = le32_to_cpu(dr->disc_size_high) << (32 - block_bits);
 340        discsize |= le32_to_cpu(dr->disc_size) >> block_bits;
 341
 342        return discsize;
 343}
 344
 345static int adfs_fill_super(struct super_block *sb, void *data, int silent)
 346{
 347        struct adfs_discrecord *dr;
 348        struct buffer_head *bh;
 349        struct object_info root_obj;
 350        unsigned char *b_data;
 351        struct adfs_sb_info *asb;
 352        struct inode *root;
 353
 354        sb->s_flags |= MS_NODIRATIME;
 355
 356        asb = kzalloc(sizeof(*asb), GFP_KERNEL);
 357        if (!asb)
 358                return -ENOMEM;
 359        sb->s_fs_info = asb;
 360
 361        /* set default options */
 362        asb->s_uid = 0;
 363        asb->s_gid = 0;
 364        asb->s_owner_mask = ADFS_DEFAULT_OWNER_MASK;
 365        asb->s_other_mask = ADFS_DEFAULT_OTHER_MASK;
 366
 367        if (parse_options(sb, data))
 368                goto error;
 369
 370        sb_set_blocksize(sb, BLOCK_SIZE);
 371        if (!(bh = sb_bread(sb, ADFS_DISCRECORD / BLOCK_SIZE))) {
 372                adfs_error(sb, "unable to read superblock");
 373                goto error;
 374        }
 375
 376        b_data = bh->b_data + (ADFS_DISCRECORD % BLOCK_SIZE);
 377
 378        if (adfs_checkbblk(b_data)) {
 379                if (!silent)
 380                        printk("VFS: Can't find an adfs filesystem on dev "
 381                                "%s.\n", sb->s_id);
 382                goto error_free_bh;
 383        }
 384
 385        dr = (struct adfs_discrecord *)(b_data + ADFS_DR_OFFSET);
 386
 387        /*
 388         * Do some sanity checks on the ADFS disc record
 389         */
 390        if (adfs_checkdiscrecord(dr)) {
 391                if (!silent)
 392                        printk("VPS: Can't find an adfs filesystem on dev "
 393                                "%s.\n", sb->s_id);
 394                goto error_free_bh;
 395        }
 396
 397        brelse(bh);
 398        if (sb_set_blocksize(sb, 1 << dr->log2secsize)) {
 399                bh = sb_bread(sb, ADFS_DISCRECORD / sb->s_blocksize);
 400                if (!bh) {
 401                        adfs_error(sb, "couldn't read superblock on "
 402                                "2nd try.");
 403                        goto error;
 404                }
 405                b_data = bh->b_data + (ADFS_DISCRECORD % sb->s_blocksize);
 406                if (adfs_checkbblk(b_data)) {
 407                        adfs_error(sb, "disc record mismatch, very weird!");
 408                        goto error_free_bh;
 409                }
 410                dr = (struct adfs_discrecord *)(b_data + ADFS_DR_OFFSET);
 411        } else {
 412                if (!silent)
 413                        printk(KERN_ERR "VFS: Unsupported blocksize on dev "
 414                                "%s.\n", sb->s_id);
 415                goto error;
 416        }
 417
 418        /*
 419         * blocksize on this device should now be set to the ADFS log2secsize
 420         */
 421
 422        sb->s_magic             = ADFS_SUPER_MAGIC;
 423        asb->s_idlen            = dr->idlen;
 424        asb->s_map_size         = dr->nzones | (dr->nzones_high << 8);
 425        asb->s_map2blk          = dr->log2bpmb - dr->log2secsize;
 426        asb->s_size             = adfs_discsize(dr, sb->s_blocksize_bits);
 427        asb->s_version          = dr->format_version;
 428        asb->s_log2sharesize    = dr->log2sharesize;
 429        
 430        asb->s_map = adfs_read_map(sb, dr);
 431        if (!asb->s_map)
 432                goto error_free_bh;
 433
 434        brelse(bh);
 435
 436        /*
 437         * set up enough so that we can read an inode
 438         */
 439        sb->s_op = &adfs_sops;
 440
 441        dr = (struct adfs_discrecord *)(asb->s_map[0].dm_bh->b_data + 4);
 442
 443        root_obj.parent_id = root_obj.file_id = le32_to_cpu(dr->root);
 444        root_obj.name_len  = 0;
 445        root_obj.loadaddr  = 0;
 446        root_obj.execaddr  = 0;
 447        root_obj.size      = ADFS_NEWDIR_SIZE;
 448        root_obj.attr      = ADFS_NDA_DIRECTORY   | ADFS_NDA_OWNER_READ |
 449                             ADFS_NDA_OWNER_WRITE | ADFS_NDA_PUBLIC_READ;
 450
 451        /*
 452         * If this is a F+ disk with variable length directories,
 453         * get the root_size from the disc record.
 454         */
 455        if (asb->s_version) {
 456                root_obj.size = le32_to_cpu(dr->root_size);
 457                asb->s_dir     = &adfs_fplus_dir_ops;
 458                asb->s_namelen = ADFS_FPLUS_NAME_LEN;
 459        } else {
 460                asb->s_dir     = &adfs_f_dir_ops;
 461                asb->s_namelen = ADFS_F_NAME_LEN;
 462        }
 463
 464        root = adfs_iget(sb, &root_obj);
 465        sb->s_root = d_alloc_root(root);
 466        if (!sb->s_root) {
 467                int i;
 468                iput(root);
 469                for (i = 0; i < asb->s_map_size; i++)
 470                        brelse(asb->s_map[i].dm_bh);
 471                kfree(asb->s_map);
 472                adfs_error(sb, "get root inode failed\n");
 473                goto error;
 474        } else
 475                sb->s_root->d_op = &adfs_dentry_operations;
 476        return 0;
 477
 478error_free_bh:
 479        brelse(bh);
 480error:
 481        sb->s_fs_info = NULL;
 482        kfree(asb);
 483        return -EINVAL;
 484}
 485
 486static int adfs_get_sb(struct file_system_type *fs_type,
 487        int flags, const char *dev_name, void *data, struct vfsmount *mnt)
 488{
 489        return get_sb_bdev(fs_type, flags, dev_name, data, adfs_fill_super,
 490                           mnt);
 491}
 492
 493static struct file_system_type adfs_fs_type = {
 494        .owner          = THIS_MODULE,
 495        .name           = "adfs",
 496        .get_sb         = adfs_get_sb,
 497        .kill_sb        = kill_block_super,
 498        .fs_flags       = FS_REQUIRES_DEV,
 499};
 500
 501static int __init init_adfs_fs(void)
 502{
 503        int err = init_inodecache();
 504        if (err)
 505                goto out1;
 506        err = register_filesystem(&adfs_fs_type);
 507        if (err)
 508                goto out;
 509        return 0;
 510out:
 511        destroy_inodecache();
 512out1:
 513        return err;
 514}
 515
 516static void __exit exit_adfs_fs(void)
 517{
 518        unregister_filesystem(&adfs_fs_type);
 519        destroy_inodecache();
 520}
 521
 522module_init(init_adfs_fs)
 523module_exit(exit_adfs_fs)
 524MODULE_LICENSE("GPL");
 525