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 "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
  25 void __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
  39 static 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
  72 static 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
  96 static 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
 117 static 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
 129 static int adfs_show_options(struct seq_file *seq, struct vfsmount *mnt)
 130 {
 131         struct adfs_sb_info *asb = ADFS_SB(mnt->mnt_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
 142         return 0;
 143 }
 144
 145 enum {Opt_uid, Opt_gid, Opt_ownmask, Opt_othmask, Opt_err};
 146
 147 static const match_table_t tokens = {
 148         {Opt_uid, "uid=%u"},
 149         {Opt_gid, "gid=%u"},
 150         {Opt_ownmask, "ownmask=%o"},
 151         {Opt_othmask, "othmask=%o"},
 152         {Opt_err, NULL}
 153 };
 154
 155 static int parse_options(struct super_block *sb, char *options)
 156 {
 157         char *p;
 158         struct adfs_sb_info *asb = ADFS_SB(sb);
 159         int option;
 160
 161         if (!options)
 162                 return 0;
 163
 164         while ((p = strsep(&options, ",")) != NULL) {
 165                 substring_t args[MAX_OPT_ARGS];
 166                 int token;
 167                 if (!*p)
 168                         continue;
 169
 170                 token = match_token(p, tokens, args);
 171                 switch (token) {
 172                 case Opt_uid:
 173                         if (match_int(args, &option))
 174                                 return -EINVAL;
 175                         asb->s_uid = option;
 176                         break;
 177                 case Opt_gid:
 178                         if (match_int(args, &option))
 179                                 return -EINVAL;
 180                         asb->s_gid = option;
 181                         break;
 182                 case Opt_ownmask:
 183                         if (match_octal(args, &option))
 184                                 return -EINVAL;
 185                         asb->s_owner_mask = option;
 186                         break;
 187                 case Opt_othmask:
 188                         if (match_octal(args, &option))
 189                                 return -EINVAL;
 190                         asb->s_other_mask = option;
 191                         break;
 192                 default:
 193                         printk("ADFS-fs: unrecognised mount option \"%s\" "
 194                                         "or missing value\n", p);
 195                         return -EINVAL;
 196                 }
 197         }
 198         return 0;
 199 }
 200
 201 static int adfs_remount(struct super_block *sb, int *flags, char *data)
 202 {
 203         *flags |= MS_NODIRATIME;
 204         return parse_options(sb, data);
 205 }
 206
 207 static int adfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 208 {
 209         struct super_block *sb = dentry->d_sb;
 210         struct adfs_sb_info *sbi = ADFS_SB(sb);
 211         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 212
 213         buf->f_type    = ADFS_SUPER_MAGIC;
 214         buf->f_namelen = sbi->s_namelen;
 215         buf->f_bsize   = sb->s_blocksize;
 216         buf->f_blocks  = sbi->s_size;
 217         buf->f_files   = sbi->s_ids_per_zone * sbi->s_map_size;
 218         buf->f_bavail  =
 219         buf->f_bfree   = adfs_map_free(sb);
 220         buf->f_ffree   = (long)(buf->f_bfree * buf->f_files) / (long)buf->f_blocks;
 221         buf->f_fsid.val[0] = (u32)id;
 222         buf->f_fsid.val[1] = (u32)(id >> 32);
 223
 224         return 0;
 225 }
 226
 227 static struct kmem_cache *adfs_inode_cachep;
 228
 229 static struct inode *adfs_alloc_inode(struct super_block *sb)
 230 {
 231         struct adfs_inode_info *ei;
 232         ei = (struct adfs_inode_info *)kmem_cache_alloc(adfs_inode_cachep, GFP_KERNEL);
 233         if (!ei)
 234                 return NULL;
 235         return &ei->vfs_inode;
 236 }
 237
 238 static void adfs_i_callback(struct rcu_head *head)
 239 {
 240         struct inode *inode = container_of(head, struct inode, i_rcu);
 241         INIT_LIST_HEAD(&inode->i_dentry);
 242         kmem_cache_free(adfs_inode_cachep, ADFS_I(inode));
 243 }
 244
 245 static void adfs_destroy_inode(struct inode *inode)
 246 {
 247         call_rcu(&inode->i_rcu, adfs_i_callback);
 248 }
 249
 250 static void init_once(void *foo)
 251 {
 252         struct adfs_inode_info *ei = (struct adfs_inode_info *) foo;
 253
 254         inode_init_once(&ei->vfs_inode);
 255 }
 256
 257 static int init_inodecache(void)
 258 {
 259         adfs_inode_cachep = kmem_cache_create("adfs_inode_cache",
 260                                              sizeof(struct adfs_inode_info),
 261                                              0, (SLAB_RECLAIM_ACCOUNT|
 262                                                 SLAB_MEM_SPREAD),
 263                                              init_once);
 264         if (adfs_inode_cachep == NULL)
 265                 return -ENOMEM;
 266         return 0;
 267 }
 268
 269 static void destroy_inodecache(void)
 270 {
 271         kmem_cache_destroy(adfs_inode_cachep);
 272 }
 273
 274 static const struct super_operations adfs_sops = {
 275         .alloc_inode    = adfs_alloc_inode,
 276         .destroy_inode  = adfs_destroy_inode,
 277         .write_inode    = adfs_write_inode,
 278         .put_super      = adfs_put_super,
 279         .statfs         = adfs_statfs,
 280         .remount_fs     = adfs_remount,
 281         .show_options   = adfs_show_options,
 282 };
 283
 284 static struct adfs_discmap *adfs_read_map(struct super_block *sb, struct adfs_discrecord *dr)
 285 {
 286         struct adfs_discmap *dm;
 287         unsigned int map_addr, zone_size, nzones;
 288         int i, zone;
 289         struct adfs_sb_info *asb = ADFS_SB(sb);
 290
 291         nzones    = asb->s_map_size;
 292         zone_size = (8 << dr->log2secsize) - le16_to_cpu(dr->zone_spare);
 293         map_addr  = (nzones >> 1) * zone_size -
 294                      ((nzones > 1) ? ADFS_DR_SIZE_BITS : 0);
 295         map_addr  = signed_asl(map_addr, asb->s_map2blk);
 296
 297         asb->s_ids_per_zone = zone_size / (asb->s_idlen + 1);
 298
 299         dm = kmalloc(nzones * sizeof(*dm), GFP_KERNEL);
 300         if (dm == NULL) {
 301                 adfs_error(sb, "not enough memory");
 302                 return NULL;
 303         }
 304
 305         for (zone = 0; zone < nzones; zone++, map_addr++) {
 306                 dm[zone].dm_startbit = 0;
 307                 dm[zone].dm_endbit   = zone_size;
 308                 dm[zone].dm_startblk = zone * zone_size - ADFS_DR_SIZE_BITS;
 309                 dm[zone].dm_bh       = sb_bread(sb, map_addr);
 310
 311                 if (!dm[zone].dm_bh) {
 312                         adfs_error(sb, "unable to read map");
 313                         goto error_free;
 314                 }
 315         }
 316
 317         /* adjust the limits for the first and last map zones */
 318         i = zone - 1;
 319         dm[0].dm_startblk = 0;
 320         dm[0].dm_startbit = ADFS_DR_SIZE_BITS;
 321         dm[i].dm_endbit   = (le32_to_cpu(dr->disc_size_high) << (32 - dr->log2bpmb)) +
 322                             (le32_to_cpu(dr->disc_size) >> dr->log2bpmb) +
 323                             (ADFS_DR_SIZE_BITS - i * zone_size);
 324
 325         if (adfs_checkmap(sb, dm))
 326                 return dm;
 327
 328         adfs_error(sb, "map corrupted");
 329
 330 error_free:
 331         while (--zone >= 0)
 332                 brelse(dm[zone].dm_bh);
 333
 334         kfree(dm);
 335         return NULL;
 336 }
 337
 338 static inline unsigned long adfs_discsize(struct adfs_discrecord *dr, int block_bits)
 339 {
 340         unsigned long discsize;
 341
 342         discsize  = le32_to_cpu(dr->disc_size_high) << (32 - block_bits);
 343         discsize |= le32_to_cpu(dr->disc_size) >> block_bits;
 344
 345         return discsize;
 346 }
 347
 348 static int adfs_fill_super(struct super_block *sb, void *data, int silent)
 349 {
 350         struct adfs_discrecord *dr;
 351         struct buffer_head *bh;
 352         struct object_info root_obj;
 353         unsigned char *b_data;
 354         struct adfs_sb_info *asb;
 355         struct inode *root;
 356
 357         sb->s_flags |= MS_NODIRATIME;
 358
 359         asb = kzalloc(sizeof(*asb), GFP_KERNEL);
 360         if (!asb)
 361                 return -ENOMEM;
 362         sb->s_fs_info = asb;
 363
 364         /* set default options */
 365         asb->s_uid = 0;
 366         asb->s_gid = 0;
 367         asb->s_owner_mask = ADFS_DEFAULT_OWNER_MASK;
 368         asb->s_other_mask = ADFS_DEFAULT_OTHER_MASK;
 369
 370         if (parse_options(sb, data))
 371                 goto error;
 372
 373         sb_set_blocksize(sb, BLOCK_SIZE);
 374         if (!(bh = sb_bread(sb, ADFS_DISCRECORD / BLOCK_SIZE))) {
 375                 adfs_error(sb, "unable to read superblock");
 376                 goto error;
 377         }
 378
 379         b_data = bh->b_data + (ADFS_DISCRECORD % BLOCK_SIZE);
 380
 381         if (adfs_checkbblk(b_data)) {
 382                 if (!silent)
 383                         printk("VFS: Can't find an adfs filesystem on dev "
 384                                 "%s.\n", sb->s_id);
 385                 goto error_free_bh;
 386         }
 387
 388         dr = (struct adfs_discrecord *)(b_data + ADFS_DR_OFFSET);
 389
 390         /*
 391          * Do some sanity checks on the ADFS disc record
 392          */
 393         if (adfs_checkdiscrecord(dr)) {
 394                 if (!silent)
 395                         printk("VPS: Can't find an adfs filesystem on dev "
 396                                 "%s.\n", sb->s_id);
 397                 goto error_free_bh;
 398         }
 399
 400         brelse(bh);
 401         if (sb_set_blocksize(sb, 1 << dr->log2secsize)) {
 402                 bh = sb_bread(sb, ADFS_DISCRECORD / sb->s_blocksize);
 403                 if (!bh) {
 404                         adfs_error(sb, "couldn't read superblock on "
 405                                 "2nd try.");
 406                         goto error;
 407                 }
 408                 b_data = bh->b_data + (ADFS_DISCRECORD % sb->s_blocksize);
 409                 if (adfs_checkbblk(b_data)) {
 410                         adfs_error(sb, "disc record mismatch, very weird!");
 411                         goto error_free_bh;
 412                 }
 413                 dr = (struct adfs_discrecord *)(b_data + ADFS_DR_OFFSET);
 414         } else {
 415                 if (!silent)
 416                         printk(KERN_ERR "VFS: Unsupported blocksize on dev "
 417                                 "%s.\n", sb->s_id);
 418                 goto error;
 419         }
 420
 421         /*
 422          * blocksize on this device should now be set to the ADFS log2secsize
 423          */
 424
 425         sb->s_magic             = ADFS_SUPER_MAGIC;
 426         asb->s_idlen            = dr->idlen;
 427         asb->s_map_size         = dr->nzones | (dr->nzones_high << 8);
 428         asb->s_map2blk          = dr->log2bpmb - dr->log2secsize;
 429         asb->s_size             = adfs_discsize(dr, sb->s_blocksize_bits);
 430         asb->s_version          = dr->format_version;
 431         asb->s_log2sharesize    = dr->log2sharesize;
 432
 433         asb->s_map = adfs_read_map(sb, dr);
 434         if (!asb->s_map)
 435                 goto error_free_bh;
 436
 437         brelse(bh);
 438
 439         /*
 440          * set up enough so that we can read an inode
 441          */
 442         sb->s_op = &adfs_sops;
 443
 444         dr = (struct adfs_discrecord *)(asb->s_map[0].dm_bh->b_data + 4);
 445
 446         root_obj.parent_id = root_obj.file_id = le32_to_cpu(dr->root);
 447         root_obj.name_len  = 0;
 448         root_obj.loadaddr  = 0;
 449         root_obj.execaddr  = 0;
 450         root_obj.size      = ADFS_NEWDIR_SIZE;
 451         root_obj.attr      = ADFS_NDA_DIRECTORY   | ADFS_NDA_OWNER_READ |
 452                              ADFS_NDA_OWNER_WRITE | ADFS_NDA_PUBLIC_READ;
 453
 454         /*
 455          * If this is a F+ disk with variable length directories,
 456          * get the root_size from the disc record.
 457          */
 458         if (asb->s_version) {
 459                 root_obj.size = le32_to_cpu(dr->root_size);
 460                 asb->s_dir     = &adfs_fplus_dir_ops;
 461                 asb->s_namelen = ADFS_FPLUS_NAME_LEN;
 462         } else {
 463                 asb->s_dir     = &adfs_f_dir_ops;
 464                 asb->s_namelen = ADFS_F_NAME_LEN;
 465         }
 466
 467         sb->s_d_op = &adfs_dentry_operations;
 468         root = adfs_iget(sb, &root_obj);
 469         sb->s_root = d_alloc_root(root);
 470         if (!sb->s_root) {
 471                 int i;
 472                 iput(root);
 473                 for (i = 0; i < asb->s_map_size; i++)
 474                         brelse(asb->s_map[i].dm_bh);
 475                 kfree(asb->s_map);
 476                 adfs_error(sb, "get root inode failed\n");
 477                 goto error;
 478         }
 479         return 0;
 480
 481 error_free_bh:
 482         brelse(bh);
 483 error:
 484         sb->s_fs_info = NULL;
 485         kfree(asb);
 486         return -EINVAL;
 487 }
 488
 489 static struct dentry *adfs_mount(struct file_system_type *fs_type,
 490         int flags, const char *dev_name, void *data)
 491 {
 492         return mount_bdev(fs_type, flags, dev_name, data, adfs_fill_super);
 493 }
 494
 495 static struct file_system_type adfs_fs_type = {
 496         .owner          = THIS_MODULE,
 497         .name           = "adfs",
 498         .mount          = adfs_mount,
 499         .kill_sb        = kill_block_super,
 500         .fs_flags       = FS_REQUIRES_DEV,
 501 };
 502
 503 static int __init init_adfs_fs(void)
 504 {
 505         int err = init_inodecache();
 506         if (err)
 507                 goto out1;
 508         err = register_filesystem(&adfs_fs_type);
 509         if (err)
 510                 goto out;
 511         return 0;
 512 out:
 513         destroy_inodecache();
 514 out1:
 515         return err;
 516 }
 517
 518 static void __exit exit_adfs_fs(void)
 519 {
 520         unregister_filesystem(&adfs_fs_type);
 521         destroy_inodecache();
 522 }
 523
 524 module_init(init_adfs_fs)
 525 module_exit(exit_adfs_fs)
 526 MODULE_LICENSE("GPL");