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 <stdarg.h>
  12 #include <linux/stat.h>
  13 #include <linux/time.h>
  14 #include <linux/affs_fs.h>
  15 #include <linux/string.h>
  16 #include <linux/mm.h>
  17 #include <linux/amigaffs.h>
  18 #include <linux/buffer_head.h>
  19
  20 extern struct timezone sys_tz;
  21
  22 static char ErrorBuffer[256];
  23
  24 /*
  25  * Functions for accessing Amiga-FFS structures.
  26  */
  27
  28
  29 /* Insert a header block bh into the directory dir
  30  * caller must hold AFFS_DIR->i_hash_lock!
  31  */
  32
  33 int
  34 affs_insert_hash(struct inode *dir, struct buffer_head *bh)
  35 {
  36         struct super_block *sb = dir->i_sb;
  37         struct buffer_head *dir_bh;
  38         u32 ino, hash_ino;
  39         int offset;
  40
  41         ino = bh->b_blocknr;
  42         offset = affs_hash_name(sb, AFFS_TAIL(sb, bh)->name + 1, AFFS_TAIL(sb, bh)->name[0]);
  43
  44         pr_debug("AFFS: insert_hash(dir=%u, ino=%d)\n", (u32)dir->i_ino, ino);
  45
  46         dir_bh = affs_bread(sb, dir->i_ino);
  47         if (!dir_bh)
  48                 return -EIO;
  49
  50         hash_ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[offset]);
  51         while (hash_ino) {
  52                 affs_brelse(dir_bh);
  53                 dir_bh = affs_bread(sb, hash_ino);
  54                 if (!dir_bh)
  55                         return -EIO;
  56                 hash_ino = be32_to_cpu(AFFS_TAIL(sb, dir_bh)->hash_chain);
  57         }
  58         AFFS_TAIL(sb, bh)->parent = cpu_to_be32(dir->i_ino);
  59         AFFS_TAIL(sb, bh)->hash_chain = 0;
  60         affs_fix_checksum(sb, bh);
  61
  62         if (dir->i_ino == dir_bh->b_blocknr)
  63                 AFFS_HEAD(dir_bh)->table[offset] = cpu_to_be32(ino);
  64         else
  65                 AFFS_TAIL(sb, dir_bh)->hash_chain = cpu_to_be32(ino);
  66
  67         affs_adjust_checksum(dir_bh, ino);
  68         mark_buffer_dirty_inode(dir_bh, dir);
  69         affs_brelse(dir_bh);
  70
  71         dir->i_mtime = dir->i_ctime = CURRENT_TIME;
  72         dir->i_version++;
  73         mark_inode_dirty(dir);
  74
  75         return 0;
  76 }
  77
  78 /* Remove a header block from its directory.
  79  * caller must hold AFFS_DIR->i_hash_lock!
  80  */
  81
  82 int
  83 affs_remove_hash(struct inode *dir, struct buffer_head *rem_bh)
  84 {
  85         struct super_block *sb;
  86         struct buffer_head *bh;
  87         u32 rem_ino, hash_ino, ino;
  88         int offset, retval;
  89
  90         sb = dir->i_sb;
  91         rem_ino = rem_bh->b_blocknr;
  92         offset = affs_hash_name(sb, AFFS_TAIL(sb, rem_bh)->name+1, AFFS_TAIL(sb, rem_bh)->name[0]);
  93         pr_debug("AFFS: remove_hash(dir=%d, ino=%d, hashval=%d)\n", (u32)dir->i_ino, rem_ino, offset);
  94
  95         bh = affs_bread(sb, dir->i_ino);
  96         if (!bh)
  97                 return -EIO;
  98
  99         retval = -ENOENT;
 100         hash_ino = be32_to_cpu(AFFS_HEAD(bh)->table[offset]);
 101         while (hash_ino) {
 102                 if (hash_ino == rem_ino) {
 103                         ino = AFFS_TAIL(sb, rem_bh)->hash_chain;
 104                         if (dir->i_ino == bh->b_blocknr)
 105                                 AFFS_HEAD(bh)->table[offset] = ino;
 106                         else
 107                                 AFFS_TAIL(sb, bh)->hash_chain = ino;
 108                         affs_adjust_checksum(bh, be32_to_cpu(ino) - hash_ino);
 109                         mark_buffer_dirty_inode(bh, dir);
 110                         AFFS_TAIL(sb, rem_bh)->parent = 0;
 111                         retval = 0;
 112                         break;
 113                 }
 114                 affs_brelse(bh);
 115                 bh = affs_bread(sb, hash_ino);
 116                 if (!bh)
 117                         return -EIO;
 118                 hash_ino = be32_to_cpu(AFFS_TAIL(sb, bh)->hash_chain);
 119         }
 120
 121         affs_brelse(bh);
 122
 123         dir->i_mtime = dir->i_ctime = CURRENT_TIME;
 124         dir->i_version++;
 125         mark_inode_dirty(dir);
 126
 127         return retval;
 128 }
 129
 130 static void
 131 affs_fix_dcache(struct dentry *dentry, u32 entry_ino)
 132 {
 133         struct inode *inode = dentry->d_inode;
 134         void *data = dentry->d_fsdata;
 135         struct list_head *head, *next;
 136
 137         spin_lock(&dcache_lock);
 138         head = &inode->i_dentry;
 139         next = head->next;
 140         while (next != head) {
 141                 dentry = list_entry(next, struct dentry, d_alias);
 142                 if (entry_ino == (u32)(long)dentry->d_fsdata) {
 143                         dentry->d_fsdata = data;
 144                         break;
 145                 }
 146                 next = next->next;
 147         }
 148         spin_unlock(&dcache_lock);
 149 }
 150
 151
 152 /* Remove header from link chain */
 153
 154 static int
 155 affs_remove_link(struct dentry *dentry)
 156 {
 157         struct inode *dir, *inode = dentry->d_inode;
 158         struct super_block *sb = inode->i_sb;
 159         struct buffer_head *bh = NULL, *link_bh = NULL;
 160         u32 link_ino, ino;
 161         int retval;
 162
 163         pr_debug("AFFS: remove_link(key=%ld)\n", inode->i_ino);
 164         retval = -EIO;
 165         bh = affs_bread(sb, inode->i_ino);
 166         if (!bh)
 167                 goto done;
 168
 169         link_ino = (u32)(long)dentry->d_fsdata;
 170         if (inode->i_ino == link_ino) {
 171                 /* we can't remove the head of the link, as its blocknr is still used as ino,
 172                  * so we remove the block of the first link instead.
 173                  */
 174                 link_ino = be32_to_cpu(AFFS_TAIL(sb, bh)->link_chain);
 175                 link_bh = affs_bread(sb, link_ino);
 176                 if (!link_bh)
 177                         goto done;
 178
 179                 dir = iget(sb, be32_to_cpu(AFFS_TAIL(sb, link_bh)->parent));
 180                 if (!dir)
 181                         goto done;
 182
 183                 affs_lock_dir(dir);
 184                 affs_fix_dcache(dentry, link_ino);
 185                 retval = affs_remove_hash(dir, link_bh);
 186                 if (retval)
 187                         goto done;
 188                 mark_buffer_dirty_inode(link_bh, inode);
 189
 190                 memcpy(AFFS_TAIL(sb, bh)->name, AFFS_TAIL(sb, link_bh)->name, 32);
 191                 retval = affs_insert_hash(dir, bh);
 192                 if (retval)
 193                         goto done;
 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))) {
 205                 if (ino == link_ino) {
 206                         ino = AFFS_TAIL(sb, link_bh)->link_chain;
 207                         AFFS_TAIL(sb, bh)->link_chain = ino;
 208                         affs_adjust_checksum(bh, be32_to_cpu(ino) - 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;
 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         u32 *ptr = (u32 *)bh->b_data;
 345         u32 sum;
 346         int bsize;
 347
 348         sum = 0;
 349         for (bsize = sb->s_blocksize / sizeof(u32); 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(u32);
 363         u32 *ptr = (u32 *)bh->b_data;
 364         u32 checksum, *checksumptr;
 365
 366         checksumptr = ptr + 5;
 367         *checksumptr = 0;
 368         for (checksum = 0; cnt > 0; ptr++, cnt--)
 369                 checksum += be32_to_cpu(*ptr);
 370         *checksumptr = cpu_to_be32(-checksum);
 371 }
 372
 373 void
 374 secs_to_datestamp(time_t secs, struct affs_date *ds)
 375 {
 376         u32      days;
 377         u32      minute;
 378
 379         secs -= sys_tz.tz_minuteswest * 60 + ((8 * 365 + 2) * 24 * 60 * 60);
 380         if (secs < 0)
 381                 secs = 0;
 382         days    = secs / 86400;
 383         secs   -= days * 86400;
 384         minute  = secs / 60;
 385         secs   -= minute * 60;
 386
 387         ds->days = be32_to_cpu(days);
 388         ds->mins = be32_to_cpu(minute);
 389         ds->ticks = be32_to_cpu(secs * 50);
 390 }
 391
 392 mode_t
 393 prot_to_mode(u32 prot)
 394 {
 395         int mode = 0;
 396
 397         if (!(prot & FIBF_NOWRITE))
 398                 mode |= S_IWUSR;
 399         if (!(prot & FIBF_NOREAD))
 400                 mode |= S_IRUSR;
 401         if (!(prot & FIBF_NOEXECUTE))
 402                 mode |= S_IXUSR;
 403         if (prot & FIBF_GRP_WRITE)
 404                 mode |= S_IWGRP;
 405         if (prot & FIBF_GRP_READ)
 406                 mode |= S_IRGRP;
 407         if (prot & FIBF_GRP_EXECUTE)
 408                 mode |= S_IXGRP;
 409         if (prot & FIBF_OTR_WRITE)
 410                 mode |= S_IWOTH;
 411         if (prot & FIBF_OTR_READ)
 412                 mode |= S_IROTH;
 413         if (prot & FIBF_OTR_EXECUTE)
 414                 mode |= S_IXOTH;
 415
 416         return mode;
 417 }
 418
 419 void
 420 mode_to_prot(struct inode *inode)
 421 {
 422         u32 prot = AFFS_I(inode)->i_protect;
 423         mode_t mode = inode->i_mode;
 424
 425         if (!(mode & S_IXUSR))
 426                 prot |= FIBF_NOEXECUTE;
 427         if (!(mode & S_IRUSR))
 428                 prot |= FIBF_NOREAD;
 429         if (!(mode & S_IWUSR))
 430                 prot |= FIBF_NOWRITE;
 431         if (mode & S_IXGRP)
 432                 prot |= FIBF_GRP_EXECUTE;
 433         if (mode & S_IRGRP)
 434                 prot |= FIBF_GRP_READ;
 435         if (mode & S_IWGRP)
 436                 prot |= FIBF_GRP_WRITE;
 437         if (mode & S_IXOTH)
 438                 prot |= FIBF_OTR_EXECUTE;
 439         if (mode & S_IROTH)
 440                 prot |= FIBF_OTR_READ;
 441         if (mode & S_IWOTH)
 442                 prot |= FIBF_OTR_WRITE;
 443
 444         AFFS_I(inode)->i_protect = prot;
 445 }
 446
 447 void
 448 affs_error(struct super_block *sb, const char *function, const char *fmt, ...)
 449 {
 450         va_list  args;
 451
 452         va_start(args,fmt);
 453         vsprintf(ErrorBuffer,fmt,args);
 454         va_end(args);
 455
 456         printk(KERN_CRIT "AFFS error (device %s): %s(): %s\n", sb->s_id,
 457                 function,ErrorBuffer);
 458         if (!(sb->s_flags & MS_RDONLY))
 459                 printk(KERN_WARNING "AFFS: Remounting filesystem read-only\n");
 460         sb->s_flags |= MS_RDONLY;
 461         AFFS_SB(sb)->s_flags |= SF_READONLY;    /* Don't allow to remount rw */
 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         vsprintf(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 }