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/errno.h>
  12#include <linux/fs.h>
  13#include <linux/adfs_fs.h>
  14#include <linux/slab.h>
  15#include <linux/time.h>
  16#include <linux/stat.h>
  17#include <linux/string.h>
  18#include <linux/init.h>
  19#include <linux/buffer_head.h>
  20#include <linux/vfs.h>
  21#include <linux/parser.h>
  22#include <linux/bitops.h>
  23
  24#include <asm/uaccess.h>
  25#include <asm/system.h>
  26
  27#include <stdarg.h>
  28
  29#include "adfs.h"
  30#include "dir_f.h"
  31#include "dir_fplus.h"
  32
  33void __adfs_error(struct super_block *sb, const char *function, const char *fmt, ...)
  34{
  35        char error_buf[128];
  36        va_list args;
  37
  38        va_start(args, fmt);
  39        vsnprintf(error_buf, sizeof(error_buf), fmt, args);
  40        va_end(args);
  41
  42        printk(KERN_CRIT "ADFS-fs error (device %s)%s%s: %s\n",
  43                sb->s_id, function ? ": " : "",
  44                function ? function : "", error_buf);
  45}
  46
  47static int adfs_checkdiscrecord(struct adfs_discrecord *dr)
  48{
  49        int i;
  50
  51        /* sector size must be 256, 512 or 1024 bytes */
  52        if (dr->log2secsize != 8 &&
  53            dr->log2secsize != 9 &&
  54            dr->log2secsize != 10)
  55                return 1;
  56
  57        /* idlen must be at least log2secsize + 3 */
  58        if (dr->idlen < dr->log2secsize + 3)
  59                return 1;
  60
  61        /* we cannot have such a large disc that we
  62         * are unable to represent sector offsets in
  63         * 32 bits.  This works out at 2.0 TB.
  64         */
  65        if (le32_to_cpu(dr->disc_size_high) >> dr->log2secsize)
  66                return 1;
  67
  68        /* idlen must be no greater than 19 v2 [1.0] */
  69        if (dr->idlen > 19)
  70                return 1;
  71
  72        /* reserved bytes should be zero */
  73        for (i = 0; i < sizeof(dr->unused52); i++)
  74                if (dr->unused52[i] != 0)
  75                        return 1;
  76
  77        return 0;
  78}
  79
  80static unsigned char adfs_calczonecheck(struct super_block *sb, unsigned char *map)
  81{
  82        unsigned int v0, v1, v2, v3;
  83        int i;
  84
  85        v0 = v1 = v2 = v3 = 0;
  86        for (i = sb->s_blocksize - 4; i; i -= 4) {
  87                v0 += map[i]     + (v3 >> 8);
  88                v3 &= 0xff;
  89                v1 += map[i + 1] + (v0 >> 8);
  90                v0 &= 0xff;
  91                v2 += map[i + 2] + (v1 >> 8);
  92                v1 &= 0xff;
  93                v3 += map[i + 3] + (v2 >> 8);
  94                v2 &= 0xff;
  95        }
  96        v0 +=           v3 >> 8;
  97        v1 += map[1] + (v0 >> 8);
  98        v2 += map[2] + (v1 >> 8);
  99        v3 += map[3] + (v2 >> 8);
 100
 101        return v0 ^ v1 ^ v2 ^ v3;
 102}
 103
 104static int adfs_checkmap(struct super_block *sb, struct adfs_discmap *dm)
 105{
 106        unsigned char crosscheck = 0, zonecheck = 1;
 107        int i;
 108
 109        for (i = 0; i < ADFS_SB(sb)->s_map_size; i++) {
 110                unsigned char *map;
 111
 112                map = dm[i].dm_bh->b_data;
 113
 114                if (adfs_calczonecheck(sb, map) != map[0]) {
 115                        adfs_error(sb, "zone %d fails zonecheck", i);
 116                        zonecheck = 0;
 117                }
 118                crosscheck ^= map[3];
 119        }
 120        if (crosscheck != 0xff)
 121                adfs_error(sb, "crosscheck != 0xff");
 122        return crosscheck == 0xff && zonecheck;
 123}
 124
 125static void adfs_put_super(struct super_block *sb)
 126{
 127        int i;
 128        struct adfs_sb_info *asb = ADFS_SB(sb);
 129
 130        for (i = 0; i < asb->s_map_size; i++)
 131                brelse(asb->s_map[i].dm_bh);
 132        kfree(asb->s_map);
 133        kfree(asb);
 134        sb->s_fs_info = NULL;
 135}
 136
 137enum {Opt_uid, Opt_gid, Opt_ownmask, Opt_othmask, Opt_err};
 138
 139static match_table_t tokens = {
 140        {Opt_uid, "uid=%u"},
 141        {Opt_gid, "gid=%u"},
 142        {Opt_ownmask, "ownmask=%o"},
 143        {Opt_othmask, "othmask=%o"},
 144        {Opt_err, NULL}
 145};
 146
 147static int parse_options(struct super_block *sb, char *options)
 148{
 149        char *p;
 150        struct adfs_sb_info *asb = ADFS_SB(sb);
 151        int option;
 152
 153        if (!options)
 154                return 0;
 155
 156        while ((p = strsep(&options, ",")) != NULL) {
 157                substring_t args[MAX_OPT_ARGS];
 158                int token;
 159                if (!*p)
 160                        continue;
 161
 162                token = match_token(p, tokens, args);
 163                switch (token) {
 164                case Opt_uid:
 165                        if (match_int(args, &option))
 166                                return -EINVAL;
 167                        asb->s_uid = option;
 168                        break;
 169                case Opt_gid:
 170                        if (match_int(args, &option))
 171                                return -EINVAL;
 172                        asb->s_gid = option;
 173                        break;
 174                case Opt_ownmask:
 175                        if (match_octal(args, &option))
 176                                return -EINVAL;
 177                        asb->s_owner_mask = option;
 178                        break;
 179                case Opt_othmask:
 180                        if (match_octal(args, &option))
 181                                return -EINVAL;
 182                        asb->s_other_mask = option;
 183                        break;
 184                default:
 185                        printk("ADFS-fs: unrecognised mount option \"%s\" "
 186                                        "or missing value\n", p);
 187                        return -EINVAL;
 188                }
 189        }
 190        return 0;
 191}
 192
 193static int adfs_remount(struct super_block *sb, int *flags, char *data)
 194{
 195        *flags |= MS_NODIRATIME;
 196        return parse_options(sb, data);
 197}
 198
 199static int adfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 200{
 201        struct adfs_sb_info *asb = ADFS_SB(dentry->d_sb);
 202
 203        buf->f_type    = ADFS_SUPER_MAGIC;
 204        buf->f_namelen = asb->s_namelen;
 205        buf->f_bsize   = dentry->d_sb->s_blocksize;
 206        buf->f_blocks  = asb->s_size;
 207        buf->f_files   = asb->s_ids_per_zone * asb->s_map_size;
 208        buf->f_bavail  =
 209        buf->f_bfree   = adfs_map_free(dentry->d_sb);
 210        buf->f_ffree   = (long)(buf->f_bfree * buf->f_files) / (long)buf->f_blocks;
 211
 212        return 0;
 213}
 214
 215static struct kmem_cache *adfs_inode_cachep;
 216
 217static struct inode *adfs_alloc_inode(struct super_block *sb)
 218{
 219        struct adfs_inode_info *ei;
 220        ei = (struct adfs_inode_info *)kmem_cache_alloc(adfs_inode_cachep, GFP_KERNEL);
 221        if (!ei)
 222                return NULL;
 223        return &ei->vfs_inode;
 224}
 225
 226static void adfs_destroy_inode(struct inode *inode)
 227{
 228        kmem_cache_free(adfs_inode_cachep, ADFS_I(inode));
 229}
 230
 231static void init_once(struct kmem_cache *cachep, void *foo)
 232{
 233        struct adfs_inode_info *ei = (struct adfs_inode_info *) foo;
 234
 235        inode_init_once(&ei->vfs_inode);
 236}
 237
 238static int init_inodecache(void)
 239{
 240        adfs_inode_cachep = kmem_cache_create("adfs_inode_cache",
 241                                             sizeof(struct adfs_inode_info),
 242                                             0, (SLAB_RECLAIM_ACCOUNT|
 243                                                SLAB_MEM_SPREAD),
 244                                             init_once);
 245        if (adfs_inode_cachep == NULL)
 246                return -ENOMEM;
 247        return 0;
 248}
 249
 250static void destroy_inodecache(void)
 251{
 252        kmem_cache_destroy(adfs_inode_cachep);
 253}
 254
 255static const struct super_operations adfs_sops = {
 256        .alloc_inode    = adfs_alloc_inode,
 257        .destroy_inode  = adfs_destroy_inode,
 258        .write_inode    = adfs_write_inode,
 259        .put_super      = adfs_put_super,
 260        .statfs         = adfs_statfs,
 261        .remount_fs     = adfs_remount,
 262};
 263
 264static struct adfs_discmap *adfs_read_map(struct super_block *sb, struct adfs_discrecord *dr)
 265{
 266        struct adfs_discmap *dm;
 267        unsigned int map_addr, zone_size, nzones;
 268        int i, zone;
 269        struct adfs_sb_info *asb = ADFS_SB(sb);
 270
 271        nzones    = asb->s_map_size;
 272        zone_size = (8 << dr->log2secsize) - le16_to_cpu(dr->zone_spare);
 273        map_addr  = (nzones >> 1) * zone_size -
 274                     ((nzones > 1) ? ADFS_DR_SIZE_BITS : 0);
 275        map_addr  = signed_asl(map_addr, asb->s_map2blk);
 276
 277        asb->s_ids_per_zone = zone_size / (asb->s_idlen + 1);
 278
 279        dm = kmalloc(nzones * sizeof(*dm), GFP_KERNEL);
 280        if (dm == NULL) {
 281                adfs_error(sb, "not enough memory");
 282                return NULL;
 283        }
 284
 285        for (zone = 0; zone < nzones; zone++, map_addr++) {
 286                dm[zone].dm_startbit = 0;
 287                dm[zone].dm_endbit   = zone_size;
 288                dm[zone].dm_startblk = zone * zone_size - ADFS_DR_SIZE_BITS;
 289                dm[zone].dm_bh       = sb_bread(sb, map_addr);
 290
 291                if (!dm[zone].dm_bh) {
 292                        adfs_error(sb, "unable to read map");
 293                        goto error_free;
 294                }
 295        }
 296
 297        /* adjust the limits for the first and last map zones */
 298        i = zone - 1;
 299        dm[0].dm_startblk = 0;
 300        dm[0].dm_startbit = ADFS_DR_SIZE_BITS;
 301        dm[i].dm_endbit   = (le32_to_cpu(dr->disc_size_high) << (32 - dr->log2bpmb)) +
 302                            (le32_to_cpu(dr->disc_size) >> dr->log2bpmb) +
 303                            (ADFS_DR_SIZE_BITS - i * zone_size);
 304
 305        if (adfs_checkmap(sb, dm))
 306                return dm;
 307
 308        adfs_error(sb, "map corrupted");
 309
 310error_free:
 311        while (--zone >= 0)
 312                brelse(dm[zone].dm_bh);
 313
 314        kfree(dm);
 315        return NULL;
 316}
 317
 318static inline unsigned long adfs_discsize(struct adfs_discrecord *dr, int block_bits)
 319{
 320        unsigned long discsize;
 321
 322        discsize  = le32_to_cpu(dr->disc_size_high) << (32 - block_bits);
 323        discsize |= le32_to_cpu(dr->disc_size) >> block_bits;
 324
 325        return discsize;
 326}
 327
 328static int adfs_fill_super(struct super_block *sb, void *data, int silent)
 329{
 330        struct adfs_discrecord *dr;
 331        struct buffer_head *bh;
 332        struct object_info root_obj;
 333        unsigned char *b_data;
 334        struct adfs_sb_info *asb;
 335        struct inode *root;
 336
 337        sb->s_flags |= MS_NODIRATIME;
 338
 339        asb = kzalloc(sizeof(*asb), GFP_KERNEL);
 340        if (!asb)
 341                return -ENOMEM;
 342        sb->s_fs_info = asb;
 343
 344        /* set default options */
 345        asb->s_uid = 0;
 346        asb->s_gid = 0;
 347        asb->s_owner_mask = S_IRWXU;
 348        asb->s_other_mask = S_IRWXG | S_IRWXO;
 349
 350        if (parse_options(sb, data))
 351                goto error;
 352
 353        sb_set_blocksize(sb, BLOCK_SIZE);
 354        if (!(bh = sb_bread(sb, ADFS_DISCRECORD / BLOCK_SIZE))) {
 355                adfs_error(sb, "unable to read superblock");
 356                goto error;
 357        }
 358
 359        b_data = bh->b_data + (ADFS_DISCRECORD % BLOCK_SIZE);
 360
 361        if (adfs_checkbblk(b_data)) {
 362                if (!silent)
 363                        printk("VFS: Can't find an adfs filesystem on dev "
 364                                "%s.\n", sb->s_id);
 365                goto error_free_bh;
 366        }
 367
 368        dr = (struct adfs_discrecord *)(b_data + ADFS_DR_OFFSET);
 369
 370        /*
 371         * Do some sanity checks on the ADFS disc record
 372         */
 373        if (adfs_checkdiscrecord(dr)) {
 374                if (!silent)
 375                        printk("VPS: Can't find an adfs filesystem on dev "
 376                                "%s.\n", sb->s_id);
 377                goto error_free_bh;
 378        }
 379
 380        brelse(bh);
 381        if (sb_set_blocksize(sb, 1 << dr->log2secsize)) {
 382                bh = sb_bread(sb, ADFS_DISCRECORD / sb->s_blocksize);
 383                if (!bh) {
 384                        adfs_error(sb, "couldn't read superblock on "
 385                                "2nd try.");
 386                        goto error;
 387                }
 388                b_data = bh->b_data + (ADFS_DISCRECORD % sb->s_blocksize);
 389                if (adfs_checkbblk(b_data)) {
 390                        adfs_error(sb, "disc record mismatch, very weird!");
 391                        goto error_free_bh;
 392                }
 393                dr = (struct adfs_discrecord *)(b_data + ADFS_DR_OFFSET);
 394        } else {
 395                if (!silent)
 396                        printk(KERN_ERR "VFS: Unsupported blocksize on dev "
 397                                "%s.\n", sb->s_id);
 398                goto error;
 399        }
 400
 401        /*
 402         * blocksize on this device should now be set to the ADFS log2secsize
 403         */
 404
 405        sb->s_magic             = ADFS_SUPER_MAGIC;
 406        asb->s_idlen            = dr->idlen;
 407        asb->s_map_size         = dr->nzones | (dr->nzones_high << 8);
 408        asb->s_map2blk          = dr->log2bpmb - dr->log2secsize;
 409        asb->s_size             = adfs_discsize(dr, sb->s_blocksize_bits);
 410        asb->s_version          = dr->format_version;
 411        asb->s_log2sharesize    = dr->log2sharesize;
 412        
 413        asb->s_map = adfs_read_map(sb, dr);
 414        if (!asb->s_map)
 415                goto error_free_bh;
 416
 417        brelse(bh);
 418
 419        /*
 420         * set up enough so that we can read an inode
 421         */
 422        sb->s_op = &adfs_sops;
 423
 424        dr = (struct adfs_discrecord *)(asb->s_map[0].dm_bh->b_data + 4);
 425
 426        root_obj.parent_id = root_obj.file_id = le32_to_cpu(dr->root);
 427        root_obj.name_len  = 0;
 428        root_obj.loadaddr  = 0;
 429        root_obj.execaddr  = 0;
 430        root_obj.size      = ADFS_NEWDIR_SIZE;
 431        root_obj.attr      = ADFS_NDA_DIRECTORY   | ADFS_NDA_OWNER_READ |
 432                             ADFS_NDA_OWNER_WRITE | ADFS_NDA_PUBLIC_READ;
 433
 434        /*
 435         * If this is a F+ disk with variable length directories,
 436         * get the root_size from the disc record.
 437         */
 438        if (asb->s_version) {
 439                root_obj.size = le32_to_cpu(dr->root_size);
 440                asb->s_dir     = &adfs_fplus_dir_ops;
 441                asb->s_namelen = ADFS_FPLUS_NAME_LEN;
 442        } else {
 443                asb->s_dir     = &adfs_f_dir_ops;
 444                asb->s_namelen = ADFS_F_NAME_LEN;
 445        }
 446
 447        root = adfs_iget(sb, &root_obj);
 448        sb->s_root = d_alloc_root(root);
 449        if (!sb->s_root) {
 450                int i;
 451                iput(root);
 452                for (i = 0; i < asb->s_map_size; i++)
 453                        brelse(asb->s_map[i].dm_bh);
 454                kfree(asb->s_map);
 455                adfs_error(sb, "get root inode failed\n");
 456                goto error;
 457        } else
 458                sb->s_root->d_op = &adfs_dentry_operations;
 459        return 0;
 460
 461error_free_bh:
 462        brelse(bh);
 463error:
 464        sb->s_fs_info = NULL;
 465        kfree(asb);
 466        return -EINVAL;
 467}
 468
 469static int adfs_get_sb(struct file_system_type *fs_type,
 470        int flags, const char *dev_name, void *data, struct vfsmount *mnt)
 471{
 472        return get_sb_bdev(fs_type, flags, dev_name, data, adfs_fill_super,
 473                           mnt);
 474}
 475
 476static struct file_system_type adfs_fs_type = {
 477        .owner          = THIS_MODULE,
 478        .name           = "adfs",
 479        .get_sb         = adfs_get_sb,
 480        .kill_sb        = kill_block_super,
 481        .fs_flags       = FS_REQUIRES_DEV,
 482};
 483
 484static int __init init_adfs_fs(void)
 485{
 486        int err = init_inodecache();
 487        if (err)
 488                goto out1;
 489        err = register_filesystem(&adfs_fs_type);
 490        if (err)
 491                goto out;
 492        return 0;
 493out:
 494        destroy_inodecache();
 495out1:
 496        return err;
 497}
 498
 499static void __exit exit_adfs_fs(void)
 500{
 501        unregister_filesystem(&adfs_fs_type);
 502        destroy_inodecache();
 503}
 504
 505module_init(init_adfs_fs)
 506module_exit(exit_adfs_fs)
 507