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 = affs_iget(sb, be32_to_cpu(AFFS_TAIL(sb, link_bh)->parent));
 174                 if (IS_ERR(dir)) {
 175                         retval = PTR_ERR(dir);
 176                         goto done;
 177                 }
 178
 179                 affs_lock_dir(dir);
 180                 affs_fix_dcache(dentry, link_ino);
 181                 retval = affs_remove_hash(dir, link_bh);
 182                 if (retval) {
 183                         affs_unlock_dir(dir);
 184                         goto done;
 185                 }
 186                 mark_buffer_dirty_inode(link_bh, inode);
 187
 188                 memcpy(AFFS_TAIL(sb, bh)->name, AFFS_TAIL(sb, link_bh)->name, 32);
 189                 retval = affs_insert_hash(dir, bh);
 190                 if (retval) {
 191                         affs_unlock_dir(dir);
 192                         goto done;
 193                 }
 194                 mark_buffer_dirty_inode(bh, inode);
 195
 196                 affs_unlock_dir(dir);
 197                 iput(dir);
 198         } else {
 199                 link_bh = affs_bread(sb, link_ino);
 200                 if (!link_bh)
 201                         goto done;
 202         }
 203
 204         while ((ino = be32_to_cpu(AFFS_TAIL(sb, bh)->link_chain)) != 0) {
 205                 if (ino == link_ino) {
 206                         __be32 ino2 = AFFS_TAIL(sb, link_bh)->link_chain;
 207                         AFFS_TAIL(sb, bh)->link_chain = ino2;
 208                         affs_adjust_checksum(bh, be32_to_cpu(ino2) - link_ino);
 209                         mark_buffer_dirty_inode(bh, inode);
 210                         retval = 0;
 211                         /* Fix the link count, if bh is a normal header block without links */
 212                         switch (be32_to_cpu(AFFS_TAIL(sb, bh)->stype)) {
 213                         case ST_LINKDIR:
 214                         case ST_LINKFILE:
 215                                 break;
 216                         default:
 217                                 if (!AFFS_TAIL(sb, bh)->link_chain)
 218                                         inode->i_nlink = 1;
 219                         }
 220                         affs_free_block(sb, link_ino);
 221                         goto done;
 222                 }
 223                 affs_brelse(bh);
 224                 bh = affs_bread(sb, ino);
 225                 if (!bh)
 226                         goto done;
 227         }
 228         retval = -ENOENT;
 229 done:
 230         affs_brelse(link_bh);
 231         affs_brelse(bh);
 232         return retval;
 233 }
 234
 235
 236 static int
 237 affs_empty_dir(struct inode *inode)
 238 {
 239         struct super_block *sb = inode->i_sb;
 240         struct buffer_head *bh;
 241         int retval, size;
 242
 243         retval = -EIO;
 244         bh = affs_bread(sb, inode->i_ino);
 245         if (!bh)
 246                 goto done;
 247
 248         retval = -ENOTEMPTY;
 249         for (size = AFFS_SB(sb)->s_hashsize - 1; size >= 0; size--)
 250                 if (AFFS_HEAD(bh)->table[size])
 251                         goto not_empty;
 252         retval = 0;
 253 not_empty:
 254         affs_brelse(bh);
 255 done:
 256         return retval;
 257 }
 258
 259
 260 /* Remove a filesystem object. If the object to be removed has
 261  * links to it, one of the links must be changed to inherit
 262  * the file or directory. As above, any inode will do.
 263  * The buffer will not be freed. If the header is a link, the
 264  * block will be marked as free.
 265  * This function returns a negative error number in case of
 266  * an error, else 0 if the inode is to be deleted or 1 if not.
 267  */
 268
 269 int
 270 affs_remove_header(struct dentry *dentry)
 271 {
 272         struct super_block *sb;
 273         struct inode *inode, *dir;
 274         struct buffer_head *bh = NULL;
 275         int retval;
 276
 277         dir = dentry->d_parent->d_inode;
 278         sb = dir->i_sb;
 279
 280         retval = -ENOENT;
 281         inode = dentry->d_inode;
 282         if (!inode)
 283                 goto done;
 284
 285         pr_debug("AFFS: remove_header(key=%ld)\n", inode->i_ino);
 286         retval = -EIO;
 287         bh = affs_bread(sb, (u32)(long)dentry->d_fsdata);
 288         if (!bh)
 289                 goto done;
 290
 291         affs_lock_link(inode);
 292         affs_lock_dir(dir);
 293         switch (be32_to_cpu(AFFS_TAIL(sb, bh)->stype)) {
 294         case ST_USERDIR:
 295                 /* if we ever want to support links to dirs
 296                  * i_hash_lock of the inode must only be
 297                  * taken after some checks
 298                  */
 299                 affs_lock_dir(inode);
 300                 retval = affs_empty_dir(inode);
 301                 affs_unlock_dir(inode);
 302                 if (retval)
 303                         goto done_unlock;
 304                 break;
 305         default:
 306                 break;
 307         }
 308
 309         retval = affs_remove_hash(dir, bh);
 310         if (retval)
 311                 goto done_unlock;
 312         mark_buffer_dirty_inode(bh, inode);
 313
 314         affs_unlock_dir(dir);
 315
 316         if (inode->i_nlink > 1)
 317                 retval = affs_remove_link(dentry);
 318         else
 319                 inode->i_nlink = 0;
 320         affs_unlock_link(inode);
 321         inode->i_ctime = CURRENT_TIME_SEC;
 322         mark_inode_dirty(inode);
 323
 324 done:
 325         affs_brelse(bh);
 326         return retval;
 327
 328 done_unlock:
 329         affs_unlock_dir(dir);
 330         affs_unlock_link(inode);
 331         goto done;
 332 }
 333
 334 /* Checksum a block, do various consistency checks and optionally return
 335    the blocks type number.  DATA points to the block.  If their pointers
 336    are non-null, *PTYPE and *STYPE are set to the primary and secondary
 337    block types respectively, *HASHSIZE is set to the size of the hashtable
 338    (which lets us calculate the block size).
 339    Returns non-zero if the block is not consistent. */
 340
 341 u32
 342 affs_checksum_block(struct super_block *sb, struct buffer_head *bh)
 343 {
 344         __be32 *ptr = (__be32 *)bh->b_data;
 345         u32 sum;
 346         int bsize;
 347
 348         sum = 0;
 349         for (bsize = sb->s_blocksize / sizeof(__be32); bsize > 0; bsize--)
 350                 sum += be32_to_cpu(*ptr++);
 351         return sum;
 352 }
 353
 354 /*
 355  * Calculate the checksum of a disk block and store it
 356  * at the indicated position.
 357  */
 358
 359 void
 360 affs_fix_checksum(struct super_block *sb, struct buffer_head *bh)
 361 {
 362         int cnt = sb->s_blocksize / sizeof(__be32);
 363         __be32 *ptr = (__be32 *)bh->b_data;
 364         u32 checksum;
 365         __be32 *checksumptr;
 366
 367         checksumptr = ptr + 5;
 368         *checksumptr = 0;
 369         for (checksum = 0; cnt > 0; ptr++, cnt--)
 370                 checksum += be32_to_cpu(*ptr);
 371         *checksumptr = cpu_to_be32(-checksum);
 372 }
 373
 374 void
 375 secs_to_datestamp(time_t secs, struct affs_date *ds)
 376 {
 377         u32      days;
 378         u32      minute;
 379
 380         secs -= sys_tz.tz_minuteswest * 60 + ((8 * 365 + 2) * 24 * 60 * 60);
 381         if (secs < 0)
 382                 secs = 0;
 383         days    = secs / 86400;
 384         secs   -= days * 86400;
 385         minute  = secs / 60;
 386         secs   -= minute * 60;
 387
 388         ds->days = cpu_to_be32(days);
 389         ds->mins = cpu_to_be32(minute);
 390         ds->ticks = cpu_to_be32(secs * 50);
 391 }
 392
 393 mode_t
 394 prot_to_mode(u32 prot)
 395 {
 396         int mode = 0;
 397
 398         if (!(prot & FIBF_NOWRITE))
 399                 mode |= S_IWUSR;
 400         if (!(prot & FIBF_NOREAD))
 401                 mode |= S_IRUSR;
 402         if (!(prot & FIBF_NOEXECUTE))
 403                 mode |= S_IXUSR;
 404         if (prot & FIBF_GRP_WRITE)
 405                 mode |= S_IWGRP;
 406         if (prot & FIBF_GRP_READ)
 407                 mode |= S_IRGRP;
 408         if (prot & FIBF_GRP_EXECUTE)
 409                 mode |= S_IXGRP;
 410         if (prot & FIBF_OTR_WRITE)
 411                 mode |= S_IWOTH;
 412         if (prot & FIBF_OTR_READ)
 413                 mode |= S_IROTH;
 414         if (prot & FIBF_OTR_EXECUTE)
 415                 mode |= S_IXOTH;
 416
 417         return mode;
 418 }
 419
 420 void
 421 mode_to_prot(struct inode *inode)
 422 {
 423         u32 prot = AFFS_I(inode)->i_protect;
 424         mode_t mode = inode->i_mode;
 425
 426         if (!(mode & S_IXUSR))
 427                 prot |= FIBF_NOEXECUTE;
 428         if (!(mode & S_IRUSR))
 429                 prot |= FIBF_NOREAD;
 430         if (!(mode & S_IWUSR))
 431                 prot |= FIBF_NOWRITE;
 432         if (mode & S_IXGRP)
 433                 prot |= FIBF_GRP_EXECUTE;
 434         if (mode & S_IRGRP)
 435                 prot |= FIBF_GRP_READ;
 436         if (mode & S_IWGRP)
 437                 prot |= FIBF_GRP_WRITE;
 438         if (mode & S_IXOTH)
 439                 prot |= FIBF_OTR_EXECUTE;
 440         if (mode & S_IROTH)
 441                 prot |= FIBF_OTR_READ;
 442         if (mode & S_IWOTH)
 443                 prot |= FIBF_OTR_WRITE;
 444
 445         AFFS_I(inode)->i_protect = prot;
 446 }
 447
 448 void
 449 affs_error(struct super_block *sb, const char *function, const char *fmt, ...)
 450 {
 451         va_list  args;
 452
 453         va_start(args,fmt);
 454         vsnprintf(ErrorBuffer,sizeof(ErrorBuffer),fmt,args);
 455         va_end(args);
 456
 457         printk(KERN_CRIT "AFFS error (device %s): %s(): %s\n", sb->s_id,
 458                 function,ErrorBuffer);
 459         if (!(sb->s_flags & MS_RDONLY))
 460                 printk(KERN_WARNING "AFFS: Remounting filesystem read-only\n");
 461         sb->s_flags |= MS_RDONLY;
 462 }
 463
 464 void
 465 affs_warning(struct super_block *sb, const char *function, const char *fmt, ...)
 466 {
 467         va_list  args;
 468
 469         va_start(args,fmt);
 470         vsnprintf(ErrorBuffer,sizeof(ErrorBuffer),fmt,args);
 471         va_end(args);
 472
 473         printk(KERN_WARNING "AFFS warning (device %s): %s(): %s\n", sb->s_id,
 474                 function,ErrorBuffer);
 475 }
 476
 477 /* Check if the name is valid for a affs object. */
 478
 479 int
 480 affs_check_name(const unsigned char *name, int len)
 481 {
 482         int      i;
 483
 484         if (len > 30)
 485 #ifdef AFFS_NO_TRUNCATE
 486                 return -ENAMETOOLONG;
 487 #else
 488                 len = 30;
 489 #endif
 490
 491         for (i = 0; i < len; i++) {
 492                 if (name[i] < ' ' || name[i] == ':'
 493                     || (name[i] > 0x7e && name[i] < 0xa0))
 494                         return -EINVAL;
 495         }
 496
 497         return 0;
 498 }
 499
 500 /* This function copies name to bstr, with at most 30
 501  * characters length. The bstr will be prepended by
 502  * a length byte.
 503  * NOTE: The name will must be already checked by
 504  *       affs_check_name()!
 505  */
 506
 507 int
 508 affs_copy_name(unsigned char *bstr, struct dentry *dentry)
 509 {
 510         int len = min(dentry->d_name.len, 30u);
 511
 512         *bstr++ = len;
 513         memcpy(bstr, dentry->d_name.name, len);
 514         return len;
 515 }