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 dentry *dentry, u32 entry_ino)
 126 {
 127         struct inode *inode = dentry->d_inode;
 128         void *data = dentry->d_fsdata;
 129         struct list_head *head, *next;
 130
 131         spin_lock(&dcache_lock);
 132         head = &inode->i_dentry;
 133         next = head->next;
 134         while (next != head) {
 135                 dentry = list_entry(next, struct dentry, d_alias);
 136                 if (entry_ino == (u32)(long)dentry->d_fsdata) {
 137                         dentry->d_fsdata = data;
 138                         break;
 139                 }
 140                 next = next->next;
 141         }
 142         spin_unlock(&dcache_lock);
 143 }
 144
 145
 146 /* Remove header from link chain */
 147
 148 static int
 149 affs_remove_link(struct dentry *dentry)
 150 {
 151         struct inode *dir, *inode = dentry->d_inode;
 152         struct super_block *sb = inode->i_sb;
 153         struct buffer_head *bh = NULL, *link_bh = NULL;
 154         u32 link_ino, ino;
 155         int retval;
 156
 157         pr_debug("AFFS: remove_link(key=%ld)\n", inode->i_ino);
 158         retval = -EIO;
 159         bh = affs_bread(sb, inode->i_ino);
 160         if (!bh)
 161                 goto done;
 162
 163         link_ino = (u32)(long)dentry->d_fsdata;
 164         if (inode->i_ino == link_ino) {
 165                 /* we can't remove the head of the link, as its blocknr is still used as ino,
 166                  * so we remove the block of the first link instead.
 167                  */
 168                 link_ino = be32_to_cpu(AFFS_TAIL(sb, bh)->link_chain);
 169                 link_bh = affs_bread(sb, link_ino);
 170                 if (!link_bh)
 171                         goto done;
 172
 173                 dir = iget(sb, be32_to_cpu(AFFS_TAIL(sb, link_bh)->parent));
 174                 if (!dir)
 175                         goto done;
 176
 177                 affs_lock_dir(dir);
 178                 affs_fix_dcache(dentry, link_ino);
 179                 retval = affs_remove_hash(dir, link_bh);
 180                 if (retval)
 181                         goto done;
 182                 mark_buffer_dirty_inode(link_bh, inode);
 183
 184                 memcpy(AFFS_TAIL(sb, bh)->name, AFFS_TAIL(sb, link_bh)->name, 32);
 185                 retval = affs_insert_hash(dir, bh);
 186                 if (retval)
 187                         goto done;
 188                 mark_buffer_dirty_inode(bh, inode);
 189
 190                 affs_unlock_dir(dir);
 191                 iput(dir);
 192         } else {
 193                 link_bh = affs_bread(sb, link_ino);
 194                 if (!link_bh)
 195                         goto done;
 196         }
 197
 198         while ((ino = be32_to_cpu(AFFS_TAIL(sb, bh)->link_chain)) != 0) {
 199                 if (ino == link_ino) {
 200                         __be32 ino2 = AFFS_TAIL(sb, link_bh)->link_chain;
 201                         AFFS_TAIL(sb, bh)->link_chain = ino2;
 202                         affs_adjust_checksum(bh, be32_to_cpu(ino2) - link_ino);
 203                         mark_buffer_dirty_inode(bh, inode);
 204                         retval = 0;
 205                         /* Fix the link count, if bh is a normal header block without links */
 206                         switch (be32_to_cpu(AFFS_TAIL(sb, bh)->stype)) {
 207                         case ST_LINKDIR:
 208                         case ST_LINKFILE:
 209                                 break;
 210                         default:
 211                                 if (!AFFS_TAIL(sb, bh)->link_chain)
 212                                         inode->i_nlink = 1;
 213                         }
 214                         affs_free_block(sb, link_ino);
 215                         goto done;
 216                 }
 217                 affs_brelse(bh);
 218                 bh = affs_bread(sb, ino);
 219                 if (!bh)
 220                         goto done;
 221         }
 222         retval = -ENOENT;
 223 done:
 224         affs_brelse(link_bh);
 225         affs_brelse(bh);
 226         return retval;
 227 }
 228
 229
 230 static int
 231 affs_empty_dir(struct inode *inode)
 232 {
 233         struct super_block *sb = inode->i_sb;
 234         struct buffer_head *bh;
 235         int retval, size;
 236
 237         retval = -EIO;
 238         bh = affs_bread(sb, inode->i_ino);
 239         if (!bh)
 240                 goto done;
 241
 242         retval = -ENOTEMPTY;
 243         for (size = AFFS_SB(sb)->s_hashsize - 1; size >= 0; size--)
 244                 if (AFFS_HEAD(bh)->table[size])
 245                         goto not_empty;
 246         retval = 0;
 247 not_empty:
 248         affs_brelse(bh);
 249 done:
 250         return retval;
 251 }
 252
 253
 254 /* Remove a filesystem object. If the object to be removed has
 255  * links to it, one of the links must be changed to inherit
 256  * the file or directory. As above, any inode will do.
 257  * The buffer will not be freed. If the header is a link, the
 258  * block will be marked as free.
 259  * This function returns a negative error number in case of
 260  * an error, else 0 if the inode is to be deleted or 1 if not.
 261  */
 262
 263 int
 264 affs_remove_header(struct dentry *dentry)
 265 {
 266         struct super_block *sb;
 267         struct inode *inode, *dir;
 268         struct buffer_head *bh = NULL;
 269         int retval;
 270
 271         dir = dentry->d_parent->d_inode;
 272         sb = dir->i_sb;
 273
 274         retval = -ENOENT;
 275         inode = dentry->d_inode;
 276         if (!inode)
 277                 goto done;
 278
 279         pr_debug("AFFS: remove_header(key=%ld)\n", inode->i_ino);
 280         retval = -EIO;
 281         bh = affs_bread(sb, (u32)(long)dentry->d_fsdata);
 282         if (!bh)
 283                 goto done;
 284
 285         affs_lock_link(inode);
 286         affs_lock_dir(dir);
 287         switch (be32_to_cpu(AFFS_TAIL(sb, bh)->stype)) {
 288         case ST_USERDIR:
 289                 /* if we ever want to support links to dirs
 290                  * i_hash_lock of the inode must only be
 291                  * taken after some checks
 292                  */
 293                 affs_lock_dir(inode);
 294                 retval = affs_empty_dir(inode);
 295                 affs_unlock_dir(inode);
 296                 if (retval)
 297                         goto done_unlock;
 298                 break;
 299         default:
 300                 break;
 301         }
 302
 303         retval = affs_remove_hash(dir, bh);
 304         if (retval)
 305                 goto done_unlock;
 306         mark_buffer_dirty_inode(bh, inode);
 307
 308         affs_unlock_dir(dir);
 309
 310         if (inode->i_nlink > 1)
 311                 retval = affs_remove_link(dentry);
 312         else
 313                 inode->i_nlink = 0;
 314         affs_unlock_link(inode);
 315         inode->i_ctime = CURRENT_TIME_SEC;
 316         mark_inode_dirty(inode);
 317
 318 done:
 319         affs_brelse(bh);
 320         return retval;
 321
 322 done_unlock:
 323         affs_unlock_dir(dir);
 324         affs_unlock_link(inode);
 325         goto done;
 326 }
 327
 328 /* Checksum a block, do various consistency checks and optionally return
 329    the blocks type number.  DATA points to the block.  If their pointers
 330    are non-null, *PTYPE and *STYPE are set to the primary and secondary
 331    block types respectively, *HASHSIZE is set to the size of the hashtable
 332    (which lets us calculate the block size).
 333    Returns non-zero if the block is not consistent. */
 334
 335 u32
 336 affs_checksum_block(struct super_block *sb, struct buffer_head *bh)
 337 {
 338         __be32 *ptr = (__be32 *)bh->b_data;
 339         u32 sum;
 340         int bsize;
 341
 342         sum = 0;
 343         for (bsize = sb->s_blocksize / sizeof(__be32); bsize > 0; bsize--)
 344                 sum += be32_to_cpu(*ptr++);
 345         return sum;
 346 }
 347
 348 /*
 349  * Calculate the checksum of a disk block and store it
 350  * at the indicated position.
 351  */
 352
 353 void
 354 affs_fix_checksum(struct super_block *sb, struct buffer_head *bh)
 355 {
 356         int cnt = sb->s_blocksize / sizeof(__be32);
 357         __be32 *ptr = (__be32 *)bh->b_data;
 358         u32 checksum;
 359         __be32 *checksumptr;
 360
 361         checksumptr = ptr + 5;
 362         *checksumptr = 0;
 363         for (checksum = 0; cnt > 0; ptr++, cnt--)
 364                 checksum += be32_to_cpu(*ptr);
 365         *checksumptr = cpu_to_be32(-checksum);
 366 }
 367
 368 void
 369 secs_to_datestamp(time_t secs, struct affs_date *ds)
 370 {
 371         u32      days;
 372         u32      minute;
 373
 374         secs -= sys_tz.tz_minuteswest * 60 + ((8 * 365 + 2) * 24 * 60 * 60);
 375         if (secs < 0)
 376                 secs = 0;
 377         days    = secs / 86400;
 378         secs   -= days * 86400;
 379         minute  = secs / 60;
 380         secs   -= minute * 60;
 381
 382         ds->days = cpu_to_be32(days);
 383         ds->mins = cpu_to_be32(minute);
 384         ds->ticks = cpu_to_be32(secs * 50);
 385 }
 386
 387 mode_t
 388 prot_to_mode(u32 prot)
 389 {
 390         int mode = 0;
 391
 392         if (!(prot & FIBF_NOWRITE))
 393                 mode |= S_IWUSR;
 394         if (!(prot & FIBF_NOREAD))
 395                 mode |= S_IRUSR;
 396         if (!(prot & FIBF_NOEXECUTE))
 397                 mode |= S_IXUSR;
 398         if (prot & FIBF_GRP_WRITE)
 399                 mode |= S_IWGRP;
 400         if (prot & FIBF_GRP_READ)
 401                 mode |= S_IRGRP;
 402         if (prot & FIBF_GRP_EXECUTE)
 403                 mode |= S_IXGRP;
 404         if (prot & FIBF_OTR_WRITE)
 405                 mode |= S_IWOTH;
 406         if (prot & FIBF_OTR_READ)
 407                 mode |= S_IROTH;
 408         if (prot & FIBF_OTR_EXECUTE)
 409                 mode |= S_IXOTH;
 410
 411         return mode;
 412 }
 413
 414 void
 415 mode_to_prot(struct inode *inode)
 416 {
 417         u32 prot = AFFS_I(inode)->i_protect;
 418         mode_t mode = inode->i_mode;
 419
 420         if (!(mode & S_IXUSR))
 421                 prot |= FIBF_NOEXECUTE;
 422         if (!(mode & S_IRUSR))
 423                 prot |= FIBF_NOREAD;
 424         if (!(mode & S_IWUSR))
 425                 prot |= FIBF_NOWRITE;
 426         if (mode & S_IXGRP)
 427                 prot |= FIBF_GRP_EXECUTE;
 428         if (mode & S_IRGRP)
 429                 prot |= FIBF_GRP_READ;
 430         if (mode & S_IWGRP)
 431                 prot |= FIBF_GRP_WRITE;
 432         if (mode & S_IXOTH)
 433                 prot |= FIBF_OTR_EXECUTE;
 434         if (mode & S_IROTH)
 435                 prot |= FIBF_OTR_READ;
 436         if (mode & S_IWOTH)
 437                 prot |= FIBF_OTR_WRITE;
 438
 439         AFFS_I(inode)->i_protect = prot;
 440 }
 441
 442 void
 443 affs_error(struct super_block *sb, const char *function, const char *fmt, ...)
 444 {
 445         va_list  args;
 446
 447         va_start(args,fmt);
 448         vsnprintf(ErrorBuffer,sizeof(ErrorBuffer),fmt,args);
 449         va_end(args);
 450
 451         printk(KERN_CRIT "AFFS error (device %s): %s(): %s\n", sb->s_id,
 452                 function,ErrorBuffer);
 453         if (!(sb->s_flags & MS_RDONLY))
 454                 printk(KERN_WARNING "AFFS: Remounting filesystem read-only\n");
 455         sb->s_flags |= MS_RDONLY;
 456 }
 457
 458 void
 459 affs_warning(struct super_block *sb, const char *function, const char *fmt, ...)
 460 {
 461         va_list  args;
 462
 463         va_start(args,fmt);
 464         vsnprintf(ErrorBuffer,sizeof(ErrorBuffer),fmt,args);
 465         va_end(args);
 466
 467         printk(KERN_WARNING "AFFS warning (device %s): %s(): %s\n", sb->s_id,
 468                 function,ErrorBuffer);
 469 }
 470
 471 /* Check if the name is valid for a affs object. */
 472
 473 int
 474 affs_check_name(const unsigned char *name, int len)
 475 {
 476         int      i;
 477
 478         if (len > 30)
 479 #ifdef AFFS_NO_TRUNCATE
 480                 return -ENAMETOOLONG;
 481 #else
 482                 len = 30;
 483 #endif
 484
 485         for (i = 0; i < len; i++) {
 486                 if (name[i] < ' ' || name[i] == ':'
 487                     || (name[i] > 0x7e && name[i] < 0xa0))
 488                         return -EINVAL;
 489         }
 490
 491         return 0;
 492 }
 493
 494 /* This function copies name to bstr, with at most 30
 495  * characters length. The bstr will be prepended by
 496  * a length byte.
 497  * NOTE: The name will must be already checked by
 498  *       affs_check_name()!
 499  */
 500
 501 int
 502 affs_copy_name(unsigned char *bstr, struct dentry *dentry)
 503 {
 504         int len = min(dentry->d_name.len, 30u);
 505
 506         *bstr++ = len;
 507         memcpy(bstr, dentry->d_name.name, len);
 508         return len;
 509 }