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 "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        for (i = 0; i < asb->s_map_size; i++)
 123                brelse(asb->s_map[i].dm_bh);
 124        kfree(asb->s_map);
 125        kfree(asb);
 126        sb->s_fs_info = NULL;
 127}
 128
 129static 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 (asb->s_uid != 0)
 134                seq_printf(seq, ",uid=%u", asb->s_uid);
 135        if (asb->s_gid != 0)
 136                seq_printf(seq, ",gid=%u", 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
 147enum {Opt_uid, Opt_gid, Opt_ownmask, Opt_othmask, Opt_ftsuffix, Opt_err};
 148
 149static 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
 158static 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 = option;
 179                        break;
 180                case Opt_gid:
 181                        if (match_int(args, &option))
 182                                return -EINVAL;
 183                        asb->s_gid = option;
 184                        break;
 185                case Opt_ownmask:
 186                        if (match_octal(args, &option))
 187                                return -EINVAL;
 188                        asb->s_owner_mask = option;
 189                        break;
 190                case Opt_othmask:
 191                        if (match_octal(args, &option))
 192                                return -EINVAL;
 193                        asb->s_other_mask = option;
 194                        break;
 195                case Opt_ftsuffix:
 196                        if (match_int(args, &option))
 197                                return -EINVAL;
 198                        asb->s_ftsuffix = option;
 199                        break;
 200                default:
 201                        printk("ADFS-fs: unrecognised mount option \"%s\" "
 202                                        "or missing value\n", p);
 203                        return -EINVAL;
 204                }
 205        }
 206        return 0;
 207}
 208
 209static int adfs_remount(struct super_block *sb, int *flags, char *data)
 210{
 211        *flags |= MS_NODIRATIME;
 212        return parse_options(sb, data);
 213}
 214
 215static int adfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 216{
 217        struct super_block *sb = dentry->d_sb;
 218        struct adfs_sb_info *sbi = ADFS_SB(sb);
 219        u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 220
 221        buf->f_type    = ADFS_SUPER_MAGIC;
 222        buf->f_namelen = sbi->s_namelen;
 223        buf->f_bsize   = sb->s_blocksize;
 224        buf->f_blocks  = sbi->s_size;
 225        buf->f_files   = sbi->s_ids_per_zone * sbi->s_map_size;
 226        buf->f_bavail  =
 227        buf->f_bfree   = adfs_map_free(sb);
 228        buf->f_ffree   = (long)(buf->f_bfree * buf->f_files) / (long)buf->f_blocks;
 229        buf->f_fsid.val[0] = (u32)id;
 230        buf->f_fsid.val[1] = (u32)(id >> 32);
 231
 232        return 0;
 233}
 234
 235static struct kmem_cache *adfs_inode_cachep;
 236
 237static struct inode *adfs_alloc_inode(struct super_block *sb)
 238{
 239        struct adfs_inode_info *ei;
 240        ei = (struct adfs_inode_info *)kmem_cache_alloc(adfs_inode_cachep, GFP_KERNEL);
 241        if (!ei)
 242                return NULL;
 243        return &ei->vfs_inode;
 244}
 245
 246static void adfs_i_callback(struct rcu_head *head)
 247{
 248        struct inode *inode = container_of(head, struct inode, i_rcu);
 249        kmem_cache_free(adfs_inode_cachep, ADFS_I(inode));
 250}
 251
 252static void adfs_destroy_inode(struct inode *inode)
 253{
 254        call_rcu(&inode->i_rcu, adfs_i_callback);
 255}
 256
 257static void init_once(void *foo)
 258{
 259        struct adfs_inode_info *ei = (struct adfs_inode_info *) foo;
 260
 261        inode_init_once(&ei->vfs_inode);
 262}
 263
 264static int init_inodecache(void)
 265{
 266        adfs_inode_cachep = kmem_cache_create("adfs_inode_cache",
 267                                             sizeof(struct adfs_inode_info),
 268                                             0, (SLAB_RECLAIM_ACCOUNT|
 269                                                SLAB_MEM_SPREAD),
 270                                             init_once);
 271        if (adfs_inode_cachep == NULL)
 272                return -ENOMEM;
 273        return 0;
 274}
 275
 276static void destroy_inodecache(void)
 277{
 278        kmem_cache_destroy(adfs_inode_cachep);
 279}
 280
 281static const struct super_operations adfs_sops = {
 282        .alloc_inode    = adfs_alloc_inode,
 283        .destroy_inode  = adfs_destroy_inode,
 284        .write_inode    = adfs_write_inode,
 285        .put_super      = adfs_put_super,
 286        .statfs         = adfs_statfs,
 287        .remount_fs     = adfs_remount,
 288        .show_options   = adfs_show_options,
 289};
 290
 291static struct adfs_discmap *adfs_read_map(struct super_block *sb, struct adfs_discrecord *dr)
 292{
 293        struct adfs_discmap *dm;
 294        unsigned int map_addr, zone_size, nzones;
 295        int i, zone;
 296        struct adfs_sb_info *asb = ADFS_SB(sb);
 297
 298        nzones    = asb->s_map_size;
 299        zone_size = (8 << dr->log2secsize) - le16_to_cpu(dr->zone_spare);
 300        map_addr  = (nzones >> 1) * zone_size -
 301                     ((nzones > 1) ? ADFS_DR_SIZE_BITS : 0);
 302        map_addr  = signed_asl(map_addr, asb->s_map2blk);
 303
 304        asb->s_ids_per_zone = zone_size / (asb->s_idlen + 1);
 305
 306        dm = kmalloc(nzones * sizeof(*dm), GFP_KERNEL);
 307        if (dm == NULL) {
 308                adfs_error(sb, "not enough memory");
 309                return NULL;
 310        }
 311
 312        for (zone = 0; zone < nzones; zone++, map_addr++) {
 313                dm[zone].dm_startbit = 0;
 314                dm[zone].dm_endbit   = zone_size;
 315                dm[zone].dm_startblk = zone * zone_size - ADFS_DR_SIZE_BITS;
 316                dm[zone].dm_bh       = sb_bread(sb, map_addr);
 317
 318                if (!dm[zone].dm_bh) {
 319                        adfs_error(sb, "unable to read map");
 320                        goto error_free;
 321                }
 322        }
 323
 324        /* adjust the limits for the first and last map zones */
 325        i = zone - 1;
 326        dm[0].dm_startblk = 0;
 327        dm[0].dm_startbit = ADFS_DR_SIZE_BITS;
 328        dm[i].dm_endbit   = (le32_to_cpu(dr->disc_size_high) << (32 - dr->log2bpmb)) +
 329                            (le32_to_cpu(dr->disc_size) >> dr->log2bpmb) +
 330                            (ADFS_DR_SIZE_BITS - i * zone_size);
 331
 332        if (adfs_checkmap(sb, dm))
 333                return dm;
 334
 335        adfs_error(sb, "map corrupted");
 336
 337error_free:
 338        while (--zone >= 0)
 339                brelse(dm[zone].dm_bh);
 340
 341        kfree(dm);
 342        return NULL;
 343}
 344
 345static inline unsigned long adfs_discsize(struct adfs_discrecord *dr, int block_bits)
 346{
 347        unsigned long discsize;
 348
 349        discsize  = le32_to_cpu(dr->disc_size_high) << (32 - block_bits);
 350        discsize |= le32_to_cpu(dr->disc_size) >> block_bits;
 351
 352        return discsize;
 353}
 354
 355static int adfs_fill_super(struct super_block *sb, void *data, int silent)
 356{
 357        struct adfs_discrecord *dr;
 358        struct buffer_head *bh;
 359        struct object_info root_obj;
 360        unsigned char *b_data;
 361        struct adfs_sb_info *asb;
 362        struct inode *root;
 363
 364        sb->s_flags |= MS_NODIRATIME;
 365
 366        asb = kzalloc(sizeof(*asb), GFP_KERNEL);
 367        if (!asb)
 368                return -ENOMEM;
 369        sb->s_fs_info = asb;
 370
 371        /* set default options */
 372        asb->s_uid = 0;
 373        asb->s_gid = 0;
 374        asb->s_owner_mask = ADFS_DEFAULT_OWNER_MASK;
 375        asb->s_other_mask = ADFS_DEFAULT_OTHER_MASK;
 376        asb->s_ftsuffix = 0;
 377
 378        if (parse_options(sb, data))
 379                goto error;
 380
 381        sb_set_blocksize(sb, BLOCK_SIZE);
 382        if (!(bh = sb_bread(sb, ADFS_DISCRECORD / BLOCK_SIZE))) {
 383                adfs_error(sb, "unable to read superblock");
 384                goto error;
 385        }
 386
 387        b_data = bh->b_data + (ADFS_DISCRECORD % BLOCK_SIZE);
 388
 389        if (adfs_checkbblk(b_data)) {
 390                if (!silent)
 391                        printk("VFS: Can't find an adfs filesystem on dev "
 392                                "%s.\n", sb->s_id);
 393                goto error_free_bh;
 394        }
 395
 396        dr = (struct adfs_discrecord *)(b_data + ADFS_DR_OFFSET);
 397
 398        /*
 399         * Do some sanity checks on the ADFS disc record
 400         */
 401        if (adfs_checkdiscrecord(dr)) {
 402                if (!silent)
 403                        printk("VPS: Can't find an adfs filesystem on dev "
 404                                "%s.\n", sb->s_id);
 405                goto error_free_bh;
 406        }
 407
 408        brelse(bh);
 409        if (sb_set_blocksize(sb, 1 << dr->log2secsize)) {
 410                bh = sb_bread(sb, ADFS_DISCRECORD / sb->s_blocksize);
 411                if (!bh) {
 412                        adfs_error(sb, "couldn't read superblock on "
 413                                "2nd try.");
 414                        goto error;
 415                }
 416                b_data = bh->b_data + (ADFS_DISCRECORD % sb->s_blocksize);
 417                if (adfs_checkbblk(b_data)) {
 418                        adfs_error(sb, "disc record mismatch, very weird!");
 419                        goto error_free_bh;
 420                }
 421                dr = (struct adfs_discrecord *)(b_data + ADFS_DR_OFFSET);
 422        } else {
 423                if (!silent)
 424                        printk(KERN_ERR "VFS: Unsupported blocksize on dev "
 425                                "%s.\n", sb->s_id);
 426                goto error;
 427        }
 428
 429        /*
 430         * blocksize on this device should now be set to the ADFS log2secsize
 431         */
 432
 433        sb->s_magic             = ADFS_SUPER_MAGIC;
 434        asb->s_idlen            = dr->idlen;
 435        asb->s_map_size         = dr->nzones | (dr->nzones_high << 8);
 436        asb->s_map2blk          = dr->log2bpmb - dr->log2secsize;
 437        asb->s_size             = adfs_discsize(dr, sb->s_blocksize_bits);
 438        asb->s_version          = dr->format_version;
 439        asb->s_log2sharesize    = dr->log2sharesize;
 440        
 441        asb->s_map = adfs_read_map(sb, dr);
 442        if (!asb->s_map)
 443                goto error_free_bh;
 444
 445        brelse(bh);
 446
 447        /*
 448         * set up enough so that we can read an inode
 449         */
 450        sb->s_op = &adfs_sops;
 451
 452        dr = (struct adfs_discrecord *)(asb->s_map[0].dm_bh->b_data + 4);
 453
 454        root_obj.parent_id = root_obj.file_id = le32_to_cpu(dr->root);
 455        root_obj.name_len  = 0;
 456        /* Set root object date as 01 Jan 1987 00:00:00 */
 457        root_obj.loadaddr  = 0xfff0003f;
 458        root_obj.execaddr  = 0xec22c000;
 459        root_obj.size      = ADFS_NEWDIR_SIZE;
 460        root_obj.attr      = ADFS_NDA_DIRECTORY   | ADFS_NDA_OWNER_READ |
 461                             ADFS_NDA_OWNER_WRITE | ADFS_NDA_PUBLIC_READ;
 462        root_obj.filetype  = -1;
 463
 464        /*
 465         * If this is a F+ disk with variable length directories,
 466         * get the root_size from the disc record.
 467         */
 468        if (asb->s_version) {
 469                root_obj.size = le32_to_cpu(dr->root_size);
 470                asb->s_dir     = &adfs_fplus_dir_ops;
 471                asb->s_namelen = ADFS_FPLUS_NAME_LEN;
 472        } else {
 473                asb->s_dir     = &adfs_f_dir_ops;
 474                asb->s_namelen = ADFS_F_NAME_LEN;
 475        }
 476        /*
 477         * ,xyz hex filetype suffix may be added by driver
 478         * to files that have valid RISC OS filetype
 479         */
 480        if (asb->s_ftsuffix)
 481                asb->s_namelen += 4;
 482
 483        sb->s_d_op = &adfs_dentry_operations;
 484        root = adfs_iget(sb, &root_obj);
 485        sb->s_root = d_make_root(root);
 486        if (!sb->s_root) {
 487                int i;
 488                for (i = 0; i < asb->s_map_size; i++)
 489                        brelse(asb->s_map[i].dm_bh);
 490                kfree(asb->s_map);
 491                adfs_error(sb, "get root inode failed\n");
 492                goto error;
 493        }
 494        return 0;
 495
 496error_free_bh:
 497        brelse(bh);
 498error:
 499        sb->s_fs_info = NULL;
 500        kfree(asb);
 501        return -EINVAL;
 502}
 503
 504static struct dentry *adfs_mount(struct file_system_type *fs_type,
 505        int flags, const char *dev_name, void *data)
 506{
 507        return mount_bdev(fs_type, flags, dev_name, data, adfs_fill_super);
 508}
 509
 510static struct file_system_type adfs_fs_type = {
 511        .owner          = THIS_MODULE,
 512        .name           = "adfs",
 513        .mount          = adfs_mount,
 514        .kill_sb        = kill_block_super,
 515        .fs_flags       = FS_REQUIRES_DEV,
 516};
 517
 518static int __init init_adfs_fs(void)
 519{
 520        int err = init_inodecache();
 521        if (err)
 522                goto out1;
 523        err = register_filesystem(&adfs_fs_type);
 524        if (err)
 525                goto out;
 526        return 0;
 527out:
 528        destroy_inodecache();
 529out1:
 530        return err;
 531}
 532
 533static void __exit exit_adfs_fs(void)
 534{
 535        unregister_filesystem(&adfs_fs_type);
 536        destroy_inodecache();
 537}
 538
 539module_init(init_adfs_fs)
 540module_exit(exit_adfs_fs)
 541MODULE_LICENSE("GPL");
 542
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