fs/affs/amigaffs.c

   1 /*
   2  *  linux/fs/affs/amigaffs.c
   3  *
   4  *  (c) 1996  Hans-Joachim Widmaier - Rewritten
   5  *
   6  *  (C) 1993  Ray Burr - Amiga FFS filesystem.
   7  *
   8  *  Please send bug reports to: hjw@zvw.de
   9  */
  10
  11 #include "affs.h"
  12
  13 extern struct timezone sys_tz;
  14
  15 static char ErrorBuffer[256];
  16
  17 /*
  18  * Functions for accessing Amiga-FFS structures.
  19  */
  20
  21
  22 /* Insert a header block bh into the directory dir
  23  * caller must hold AFFS_DIR->i_hash_lock!
  24  */
  25
  26 int
  27 affs_insert_hash(struct inode *dir, struct buffer_head *bh)
  28 {
  29         struct super_block *sb = dir->i_sb;
  30         struct buffer_head *dir_bh;
  31         u32 ino, hash_ino;
  32         int offset;
  33
  34         ino = bh->b_blocknr;
  35         offset = affs_hash_name(sb, AFFS_TAIL(sb, bh)->name + 1, AFFS_TAIL(sb, bh)->name[0]);
  36
  37         pr_debug("AFFS: insert_hash(dir=%u, ino=%d)\n", (u32)dir->i_ino, ino);
  38
  39         dir_bh = affs_bread(sb, dir->i_ino);
  40         if (!dir_bh)
  41                 return -EIO;
  42
  43         hash_ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[offset]);
  44         while (hash_ino) {
  45                 affs_brelse(dir_bh);
  46                 dir_bh = affs_bread(sb, hash_ino);
  47                 if (!dir_bh)
  48                         return -EIO;
  49                 hash_ino = be32_to_cpu(AFFS_TAIL(sb, dir_bh)->hash_chain);
  50         }
  51         AFFS_TAIL(sb, bh)->parent = cpu_to_be32(dir->i_ino);
  52         AFFS_TAIL(sb, bh)->hash_chain = 0;
  53         affs_fix_checksum(sb, bh);
  54
  55         if (dir->i_ino == dir_bh->b_blocknr)
  56                 AFFS_HEAD(dir_bh)->table[offset] = cpu_to_be32(ino);
  57         else
  58                 AFFS_TAIL(sb, dir_bh)->hash_chain = cpu_to_be32(ino);
  59
  60         affs_adjust_checksum(dir_bh, ino);
  61         mark_buffer_dirty_inode(dir_bh, dir);
  62         affs_brelse(dir_bh);
  63
  64         dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
  65         dir->i_version++;
  66         mark_inode_dirty(dir);
  67
  68         return 0;
  69 }
  70
  71 /* Remove a header block from its directory.
  72  * caller must hold AFFS_DIR->i_hash_lock!
  73  */
  74
  75 int
  76 affs_remove_hash(struct inode *dir, struct buffer_head *rem_bh)
  77 {
  78         struct super_block *sb;
  79         struct buffer_head *bh;
  80         u32 rem_ino, hash_ino;
  81         __be32 ino;
  82         int offset, retval;
  83
  84         sb = dir->i_sb;
  85         rem_ino = rem_bh->b_blocknr;
  86         offset = affs_hash_name(sb, AFFS_TAIL(sb, rem_bh)->name+1, AFFS_TAIL(sb, rem_bh)->name[0]);
  87         pr_debug("AFFS: remove_hash(dir=%d, ino=%d, hashval=%d)\n", (u32)dir->i_ino, rem_ino, offset);
  88
  89         bh = affs_bread(sb, dir->i_ino);
  90         if (!bh)
  91                 return -EIO;
  92
  93         retval = -ENOENT;
  94         hash_ino = be32_to_cpu(AFFS_HEAD(bh)->table[offset]);
  95         while (hash_ino) {
  96                 if (hash_ino == rem_ino) {
  97                         ino = AFFS_TAIL(sb, rem_bh)->hash_chain;
  98                         if (dir->i_ino == bh->b_blocknr)
  99                                 AFFS_HEAD(bh)->table[offset] = ino;
 100                         else
 101                                 AFFS_TAIL(sb, bh)->hash_chain = ino;
 102                         affs_adjust_checksum(bh, be32_to_cpu(ino) - hash_ino);
 103                         mark_buffer_dirty_inode(bh, dir);
 104                         AFFS_TAIL(sb, rem_bh)->parent = 0;
 105                         retval = 0;
 106                         break;
 107                 }
 108                 affs_brelse(bh);
 109                 bh = affs_bread(sb, hash_ino);
 110                 if (!bh)
 111                         return -EIO;
 112                 hash_ino = be32_to_cpu(AFFS_TAIL(sb, bh)->hash_chain);
 113         }
 114
 115         affs_brelse(bh);
 116
 117         dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
 118         dir->i_version++;
 119         mark_inode_dirty(dir);
 120
 121         return retval;
 122 }
 123
 124 static void
 125 affs_fix_dcache(struct inode *inode, u32 entry_ino)
 126 {
 127         struct dentry *dentry;
 128         struct hlist_node *p;
 129         spin_lock(&inode->i_lock);
 130         hlist_for_each_entry(dentry, p, &inode->i_dentry, d_alias) {
 131                 if (entry_ino == (u32)(long)dentry->d_fsdata) {
 132                         dentry->d_fsdata = (void *)inode->i_ino;
 133                         break;
 134                 }
 135         }
 136         spin_unlock(&inode->i_lock);
 137 }
 138
 139
 140 /* Remove header from link chain */
 141
 142 static int
 143 affs_remove_link(struct dentry *dentry)
 144 {
 145         struct inode *dir, *inode = dentry->d_inode;
 146         struct super_block *sb = inode->i_sb;
 147         struct buffer_head *bh = NULL, *link_bh = NULL;
 148         u32 link_ino, ino;
 149         int retval;
 150
 151         pr_debug("AFFS: remove_link(key=%ld)\n", inode->i_ino);
 152         retval = -EIO;
 153         bh = affs_bread(sb, inode->i_ino);
 154         if (!bh)
 155                 goto done;
 156
 157         link_ino = (u32)(long)dentry->d_fsdata;
 158         if (inode->i_ino == link_ino) {
 159                 /* we can't remove the head of the link, as its blocknr is still used as ino,
 160                  * so we remove the block of the first link instead.
 161                  */
 162                 link_ino = be32_to_cpu(AFFS_TAIL(sb, bh)->link_chain);
 163                 link_bh = affs_bread(sb, link_ino);
 164                 if (!link_bh)
 165                         goto done;
 166
 167                 dir = affs_iget(sb, be32_to_cpu(AFFS_TAIL(sb, link_bh)->parent));
 168                 if (IS_ERR(dir)) {
 169                         retval = PTR_ERR(dir);
 170                         goto done;
 171                 }
 172
 173                 affs_lock_dir(dir);
 174                 /*
 175                  * if there's a dentry for that block, make it
 176                  * refer to inode itself.
 177                  */
 178                 affs_fix_dcache(inode, link_ino);
 179                 retval = affs_remove_hash(dir, link_bh);
 180                 if (retval) {
 181                         affs_unlock_dir(dir);
 182                         goto done;
 183                 }
 184                 mark_buffer_dirty_inode(link_bh, inode);
 185
 186                 memcpy(AFFS_TAIL(sb, bh)->name, AFFS_TAIL(sb, link_bh)->name, 32);
 187                 retval = affs_insert_hash(dir, bh);
 188                 if (retval) {
 189                         affs_unlock_dir(dir);
 190                         goto done;
 191                 }
 192                 mark_buffer_dirty_inode(bh, inode);
 193
 194                 affs_unlock_dir(dir);
 195                 iput(dir);
 196         } else {
 197                 link_bh = affs_bread(sb, link_ino);
 198                 if (!link_bh)
 199                         goto done;
 200         }
 201
 202         while ((ino = be32_to_cpu(AFFS_TAIL(sb, bh)->link_chain)) != 0) {
 203                 if (ino == link_ino) {
 204                         __be32 ino2 = AFFS_TAIL(sb, link_bh)->link_chain;
 205                         AFFS_TAIL(sb, bh)->link_chain = ino2;
 206                         affs_adjust_checksum(bh, be32_to_cpu(ino2) - link_ino);
 207                         mark_buffer_dirty_inode(bh, inode);
 208                         retval = 0;
 209                         /* Fix the link count, if bh is a normal header block without links */
 210                         switch (be32_to_cpu(AFFS_TAIL(sb, bh)->stype)) {
 211                         case ST_LINKDIR:
 212                         case ST_LINKFILE:
 213                                 break;
 214                         default:
 215                                 if (!AFFS_TAIL(sb, bh)->link_chain)
 216                                         set_nlink(inode, 1);
 217                         }
 218                         affs_free_block(sb, link_ino);
 219                         goto done;
 220                 }
 221                 affs_brelse(bh);
 222                 bh = affs_bread(sb, ino);
 223                 if (!bh)
 224                         goto done;
 225         }
 226         retval = -ENOENT;
 227 done:
 228         affs_brelse(link_bh);
 229         affs_brelse(bh);
 230         return retval;
 231 }
 232
 233
 234 static int
 235 affs_empty_dir(struct inode *inode)
 236 {
 237         struct super_block *sb = inode->i_sb;
 238         struct buffer_head *bh;
 239         int retval, size;
 240
 241         retval = -EIO;
 242         bh = affs_bread(sb, inode->i_ino);
 243         if (!bh)
 244                 goto done;
 245
 246         retval = -ENOTEMPTY;
 247         for (size = AFFS_SB(sb)->s_hashsize - 1; size >= 0; size--)
 248                 if (AFFS_HEAD(bh)->table[size])
 249                         goto not_empty;
 250         retval = 0;
 251 not_empty:
 252         affs_brelse(bh);
 253 done:
 254         return retval;
 255 }
 256
 257
 258 /* Remove a filesystem object. If the object to be removed has
 259  * links to it, one of the links must be changed to inherit
 260  * the file or directory. As above, any inode will do.
 261  * The buffer will not be freed. If the header is a link, the
 262  * block will be marked as free.
 263  * This function returns a negative error number in case of
 264  * an error, else 0 if the inode is to be deleted or 1 if not.
 265  */
 266
 267 int
 268 affs_remove_header(struct dentry *dentry)
 269 {
 270         struct super_block *sb;
 271         struct inode *inode, *dir;
 272         struct buffer_head *bh = NULL;
 273         int retval;
 274
 275         dir = dentry->d_parent->d_inode;
 276         sb = dir->i_sb;
 277
 278         retval = -ENOENT;
 279         inode = dentry->d_inode;
 280         if (!inode)
 281                 goto done;
 282
 283         pr_debug("AFFS: remove_header(key=%ld)\n", inode->i_ino);
 284         retval = -EIO;
 285         bh = affs_bread(sb, (u32)(long)dentry->d_fsdata);
 286         if (!bh)
 287                 goto done;
 288
 289         affs_lock_link(inode);
 290         affs_lock_dir(dir);
 291         switch (be32_to_cpu(AFFS_TAIL(sb, bh)->stype)) {
 292         case ST_USERDIR:
 293                 /* if we ever want to support links to dirs
 294                  * i_hash_lock of the inode must only be
 295                  * taken after some checks
 296                  */
 297                 affs_lock_dir(inode);
 298                 retval = affs_empty_dir(inode);
 299                 affs_unlock_dir(inode);
 300                 if (retval)
 301                         goto done_unlock;
 302                 break;
 303         default:
 304                 break;
 305         }
 306
 307         retval = affs_remove_hash(dir, bh);
 308         if (retval)
 309                 goto done_unlock;
 310         mark_buffer_dirty_inode(bh, inode);
 311
 312         affs_unlock_dir(dir);
 313
 314         if (inode->i_nlink > 1)
 315                 retval = affs_remove_link(dentry);
 316         else
 317                 clear_nlink(inode);
 318         affs_unlock_link(inode);
 319         inode->i_ctime = CURRENT_TIME_SEC;
 320         mark_inode_dirty(inode);
 321
 322 done:
 323         affs_brelse(bh);
 324         return retval;
 325
 326 done_unlock:
 327         affs_unlock_dir(dir);
 328         affs_unlock_link(inode);
 329         goto done;
 330 }
 331
 332 /* Checksum a block, do various consistency checks and optionally return
 333    the blocks type number.  DATA points to the block.  If their pointers
 334    are non-null, *PTYPE and *STYPE are set to the primary and secondary
 335    block types respectively, *HASHSIZE is set to the size of the hashtable
 336    (which lets us calculate the block size).
 337    Returns non-zero if the block is not consistent. */
 338
 339 u32
 340 affs_checksum_block(struct super_block *sb, struct buffer_head *bh)
 341 {
 342         __be32 *ptr = (__be32 *)bh->b_data;
 343         u32 sum;
 344         int bsize;
 345
 346         sum = 0;
 347         for (bsize = sb->s_blocksize / sizeof(__be32); bsize > 0; bsize--)
 348                 sum += be32_to_cpu(*ptr++);
 349         return sum;
 350 }
 351
 352 /*
 353  * Calculate the checksum of a disk block and store it
 354  * at the indicated position.
 355  */
 356
 357 void
 358 affs_fix_checksum(struct super_block *sb, struct buffer_head *bh)
 359 {
 360         int cnt = sb->s_blocksize / sizeof(__be32);
 361         __be32 *ptr = (__be32 *)bh->b_data;
 362         u32 checksum;
 363         __be32 *checksumptr;
 364
 365         checksumptr = ptr + 5;
 366         *checksumptr = 0;
 367         for (checksum = 0; cnt > 0; ptr++, cnt--)
 368                 checksum += be32_to_cpu(*ptr);
 369         *checksumptr = cpu_to_be32(-checksum);
 370 }
 371
 372 void
 373 secs_to_datestamp(time_t secs, struct affs_date *ds)
 374 {
 375         u32      days;
 376         u32      minute;
 377
 378         secs -= sys_tz.tz_minuteswest * 60 + ((8 * 365 + 2) * 24 * 60 * 60);
 379         if (secs < 0)
 380                 secs = 0;
 381         days    = secs / 86400;
 382         secs   -= days * 86400;
 383         minute  = secs / 60;
 384         secs   -= minute * 60;
 385
 386         ds->days = cpu_to_be32(days);
 387         ds->mins = cpu_to_be32(minute);
 388         ds->ticks = cpu_to_be32(secs * 50);
 389 }
 390
 391 umode_t
 392 prot_to_mode(u32 prot)
 393 {
 394         umode_t mode = 0;
 395
 396         if (!(prot & FIBF_NOWRITE))
 397                 mode |= S_IWUSR;
 398         if (!(prot & FIBF_NOREAD))
 399                 mode |= S_IRUSR;
 400         if (!(prot & FIBF_NOEXECUTE))
 401                 mode |= S_IXUSR;
 402         if (prot & FIBF_GRP_WRITE)
 403                 mode |= S_IWGRP;
 404         if (prot & FIBF_GRP_READ)
 405                 mode |= S_IRGRP;
 406         if (prot & FIBF_GRP_EXECUTE)
 407                 mode |= S_IXGRP;
 408         if (prot & FIBF_OTR_WRITE)
 409                 mode |= S_IWOTH;
 410         if (prot & FIBF_OTR_READ)
 411                 mode |= S_IROTH;
 412         if (prot & FIBF_OTR_EXECUTE)
 413                 mode |= S_IXOTH;
 414
 415         return mode;
 416 }
 417
 418 void
 419 mode_to_prot(struct inode *inode)
 420 {
 421         u32 prot = AFFS_I(inode)->i_protect;
 422         umode_t mode = inode->i_mode;
 423
 424         if (!(mode & S_IXUSR))
 425                 prot |= FIBF_NOEXECUTE;
 426         if (!(mode & S_IRUSR))
 427                 prot |= FIBF_NOREAD;
 428         if (!(mode & S_IWUSR))
 429                 prot |= FIBF_NOWRITE;
 430         if (mode & S_IXGRP)
 431                 prot |= FIBF_GRP_EXECUTE;
 432         if (mode & S_IRGRP)
 433                 prot |= FIBF_GRP_READ;
 434         if (mode & S_IWGRP)
 435                 prot |= FIBF_GRP_WRITE;
 436         if (mode & S_IXOTH)
 437                 prot |= FIBF_OTR_EXECUTE;
 438         if (mode & S_IROTH)
 439                 prot |= FIBF_OTR_READ;
 440         if (mode & S_IWOTH)
 441                 prot |= FIBF_OTR_WRITE;
 442
 443         AFFS_I(inode)->i_protect = prot;
 444 }
 445
 446 void
 447 affs_error(struct super_block *sb, const char *function, const char *fmt, ...)
 448 {
 449         va_list  args;
 450
 451         va_start(args,fmt);
 452         vsnprintf(ErrorBuffer,sizeof(ErrorBuffer),fmt,args);
 453         va_end(args);
 454
 455         printk(KERN_CRIT "AFFS error (device %s): %s(): %s\n", sb->s_id,
 456                 function,ErrorBuffer);
 457         if (!(sb->s_flags & MS_RDONLY))
 458                 printk(KERN_WARNING "AFFS: Remounting filesystem read-only\n");
 459         sb->s_flags |= MS_RDONLY;
 460 }
 461
 462 void
 463 affs_warning(struct super_block *sb, const char *function, const char *fmt, ...)
 464 {
 465         va_list  args;
 466
 467         va_start(args,fmt);
 468         vsnprintf(ErrorBuffer,sizeof(ErrorBuffer),fmt,args);
 469         va_end(args);
 470
 471         printk(KERN_WARNING "AFFS warning (device %s): %s(): %s\n", sb->s_id,
 472                 function,ErrorBuffer);
 473 }
 474
 475 /* Check if the name is valid for a affs object. */
 476
 477 int
 478 affs_check_name(const unsigned char *name, int len)
 479 {
 480         int      i;
 481
 482         if (len > 30)
 483 #ifdef AFFS_NO_TRUNCATE
 484                 return -ENAMETOOLONG;
 485 #else
 486                 len = 30;
 487 #endif
 488
 489         for (i = 0; i < len; i++) {
 490                 if (name[i] < ' ' || name[i] == ':'
 491                     || (name[i] > 0x7e && name[i] < 0xa0))
 492                         return -EINVAL;
 493         }
 494
 495         return 0;
 496 }
 497
 498 /* This function copies name to bstr, with at most 30
 499  * characters length. The bstr will be prepended by
 500  * a length byte.
 501  * NOTE: The name will must be already checked by
 502  *       affs_check_name()!
 503  */
 504
 505 int
 506 affs_copy_name(unsigned char *bstr, struct dentry *dentry)
 507 {
 508         int len = min(dentry->d_name.len, 30u);
 509
 510         *bstr++ = len;
 511         memcpy(bstr, dentry->d_name.name, len);
 512         return len;
 513 }