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 <linux/math64.h>
  12 #include "affs.h"
  13
  14 /*
  15  * Functions for accessing Amiga-FFS structures.
  16  */
  17
  18
  19 /* Insert a header block bh into the directory dir
  20  * caller must hold AFFS_DIR->i_hash_lock!
  21  */
  22
  23 int
  24 affs_insert_hash(struct inode *dir, struct buffer_head *bh)
  25 {
  26         struct super_block *sb = dir->i_sb;
  27         struct buffer_head *dir_bh;
  28         u32 ino, hash_ino;
  29         int offset;
  30
  31         ino = bh->b_blocknr;
  32         offset = affs_hash_name(sb, AFFS_TAIL(sb, bh)->name + 1, AFFS_TAIL(sb, bh)->name[0]);
  33
  34         pr_debug("%s(dir=%lu, ino=%d)\n", __func__, dir->i_ino, ino);
  35
  36         dir_bh = affs_bread(sb, dir->i_ino);
  37         if (!dir_bh)
  38                 return -EIO;
  39
  40         hash_ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[offset]);
  41         while (hash_ino) {
  42                 affs_brelse(dir_bh);
  43                 dir_bh = affs_bread(sb, hash_ino);
  44                 if (!dir_bh)
  45                         return -EIO;
  46                 hash_ino = be32_to_cpu(AFFS_TAIL(sb, dir_bh)->hash_chain);
  47         }
  48         AFFS_TAIL(sb, bh)->parent = cpu_to_be32(dir->i_ino);
  49         AFFS_TAIL(sb, bh)->hash_chain = 0;
  50         affs_fix_checksum(sb, bh);
  51
  52         if (dir->i_ino == dir_bh->b_blocknr)
  53                 AFFS_HEAD(dir_bh)->table[offset] = cpu_to_be32(ino);
  54         else
  55                 AFFS_TAIL(sb, dir_bh)->hash_chain = cpu_to_be32(ino);
  56
  57         affs_adjust_checksum(dir_bh, ino);
  58         mark_buffer_dirty_inode(dir_bh, dir);
  59         affs_brelse(dir_bh);
  60
  61         dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
  62         dir->i_version++;
  63         mark_inode_dirty(dir);
  64
  65         return 0;
  66 }
  67
  68 /* Remove a header block from its directory.
  69  * caller must hold AFFS_DIR->i_hash_lock!
  70  */
  71
  72 int
  73 affs_remove_hash(struct inode *dir, struct buffer_head *rem_bh)
  74 {
  75         struct super_block *sb;
  76         struct buffer_head *bh;
  77         u32 rem_ino, hash_ino;
  78         __be32 ino;
  79         int offset, retval;
  80
  81         sb = dir->i_sb;
  82         rem_ino = rem_bh->b_blocknr;
  83         offset = affs_hash_name(sb, AFFS_TAIL(sb, rem_bh)->name+1, AFFS_TAIL(sb, rem_bh)->name[0]);
  84         pr_debug("%s(dir=%lu, ino=%d, hashval=%d)\n", __func__, dir->i_ino,
  85                  rem_ino, offset);
  86
  87         bh = affs_bread(sb, dir->i_ino);
  88         if (!bh)
  89                 return -EIO;
  90
  91         retval = -ENOENT;
  92         hash_ino = be32_to_cpu(AFFS_HEAD(bh)->table[offset]);
  93         while (hash_ino) {
  94                 if (hash_ino == rem_ino) {
  95                         ino = AFFS_TAIL(sb, rem_bh)->hash_chain;
  96                         if (dir->i_ino == bh->b_blocknr)
  97                                 AFFS_HEAD(bh)->table[offset] = ino;
  98                         else
  99                                 AFFS_TAIL(sb, bh)->hash_chain = ino;
 100                         affs_adjust_checksum(bh, be32_to_cpu(ino) - hash_ino);
 101                         mark_buffer_dirty_inode(bh, dir);
 102                         AFFS_TAIL(sb, rem_bh)->parent = 0;
 103                         retval = 0;
 104                         break;
 105                 }
 106                 affs_brelse(bh);
 107                 bh = affs_bread(sb, hash_ino);
 108                 if (!bh)
 109                         return -EIO;
 110                 hash_ino = be32_to_cpu(AFFS_TAIL(sb, bh)->hash_chain);
 111         }
 112
 113         affs_brelse(bh);
 114
 115         dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
 116         dir->i_version++;
 117         mark_inode_dirty(dir);
 118
 119         return retval;
 120 }
 121
 122 static void
 123 affs_fix_dcache(struct inode *inode, u32 entry_ino)
 124 {
 125         struct dentry *dentry;
 126         spin_lock(&inode->i_lock);
 127         hlist_for_each_entry(dentry, &inode->i_dentry, d_u.d_alias) {
 128                 if (entry_ino == (u32)(long)dentry->d_fsdata) {
 129                         dentry->d_fsdata = (void *)inode->i_ino;
 130                         break;
 131                 }
 132         }
 133         spin_unlock(&inode->i_lock);
 134 }
 135
 136
 137 /* Remove header from link chain */
 138
 139 static int
 140 affs_remove_link(struct dentry *dentry)
 141 {
 142         struct inode *dir, *inode = d_inode(dentry);
 143         struct super_block *sb = inode->i_sb;
 144         struct buffer_head *bh, *link_bh = NULL;
 145         u32 link_ino, ino;
 146         int retval;
 147
 148         pr_debug("%s(key=%ld)\n", __func__, inode->i_ino);
 149         retval = -EIO;
 150         bh = affs_bread(sb, inode->i_ino);
 151         if (!bh)
 152                 goto done;
 153
 154         link_ino = (u32)(long)dentry->d_fsdata;
 155         if (inode->i_ino == link_ino) {
 156                 /* we can't remove the head of the link, as its blocknr is still used as ino,
 157                  * so we remove the block of the first link instead.
 158                  */
 159                 link_ino = be32_to_cpu(AFFS_TAIL(sb, bh)->link_chain);
 160                 link_bh = affs_bread(sb, link_ino);
 161                 if (!link_bh)
 162                         goto done;
 163
 164                 dir = affs_iget(sb, be32_to_cpu(AFFS_TAIL(sb, link_bh)->parent));
 165                 if (IS_ERR(dir)) {
 166                         retval = PTR_ERR(dir);
 167                         goto done;
 168                 }
 169
 170                 affs_lock_dir(dir);
 171                 /*
 172                  * if there's a dentry for that block, make it
 173                  * refer to inode itself.
 174                  */
 175                 affs_fix_dcache(inode, link_ino);
 176                 retval = affs_remove_hash(dir, link_bh);
 177                 if (retval) {
 178                         affs_unlock_dir(dir);
 179                         goto done;
 180                 }
 181                 mark_buffer_dirty_inode(link_bh, inode);
 182
 183                 memcpy(AFFS_TAIL(sb, bh)->name, AFFS_TAIL(sb, link_bh)->name, 32);
 184                 retval = affs_insert_hash(dir, bh);
 185                 if (retval) {
 186                         affs_unlock_dir(dir);
 187                         goto done;
 188                 }
 189                 mark_buffer_dirty_inode(bh, inode);
 190
 191                 affs_unlock_dir(dir);
 192                 iput(dir);
 193         } else {
 194                 link_bh = affs_bread(sb, link_ino);
 195                 if (!link_bh)
 196                         goto done;
 197         }
 198
 199         while ((ino = be32_to_cpu(AFFS_TAIL(sb, bh)->link_chain)) != 0) {
 200                 if (ino == link_ino) {
 201                         __be32 ino2 = AFFS_TAIL(sb, link_bh)->link_chain;
 202                         AFFS_TAIL(sb, bh)->link_chain = ino2;
 203                         affs_adjust_checksum(bh, be32_to_cpu(ino2) - link_ino);
 204                         mark_buffer_dirty_inode(bh, inode);
 205                         retval = 0;
 206                         /* Fix the link count, if bh is a normal header block without links */
 207                         switch (be32_to_cpu(AFFS_TAIL(sb, bh)->stype)) {
 208                         case ST_LINKDIR:
 209                         case ST_LINKFILE:
 210                                 break;
 211                         default:
 212                                 if (!AFFS_TAIL(sb, bh)->link_chain)
 213                                         set_nlink(inode, 1);
 214                         }
 215                         affs_free_block(sb, link_ino);
 216                         goto done;
 217                 }
 218                 affs_brelse(bh);
 219                 bh = affs_bread(sb, ino);
 220                 if (!bh)
 221                         goto done;
 222         }
 223         retval = -ENOENT;
 224 done:
 225         affs_brelse(link_bh);
 226         affs_brelse(bh);
 227         return retval;
 228 }
 229
 230
 231 static int
 232 affs_empty_dir(struct inode *inode)
 233 {
 234         struct super_block *sb = inode->i_sb;
 235         struct buffer_head *bh;
 236         int retval, size;
 237
 238         retval = -EIO;
 239         bh = affs_bread(sb, inode->i_ino);
 240         if (!bh)
 241                 goto done;
 242
 243         retval = -ENOTEMPTY;
 244         for (size = AFFS_SB(sb)->s_hashsize - 1; size >= 0; size--)
 245                 if (AFFS_HEAD(bh)->table[size])
 246                         goto not_empty;
 247         retval = 0;
 248 not_empty:
 249         affs_brelse(bh);
 250 done:
 251         return retval;
 252 }
 253
 254
 255 /* Remove a filesystem object. If the object to be removed has
 256  * links to it, one of the links must be changed to inherit
 257  * the file or directory. As above, any inode will do.
 258  * The buffer will not be freed. If the header is a link, the
 259  * block will be marked as free.
 260  * This function returns a negative error number in case of
 261  * an error, else 0 if the inode is to be deleted or 1 if not.
 262  */
 263
 264 int
 265 affs_remove_header(struct dentry *dentry)
 266 {
 267         struct super_block *sb;
 268         struct inode *inode, *dir;
 269         struct buffer_head *bh = NULL;
 270         int retval;
 271
 272         dir = d_inode(dentry->d_parent);
 273         sb = dir->i_sb;
 274
 275         retval = -ENOENT;
 276         inode = d_inode(dentry);
 277         if (!inode)
 278                 goto done;
 279
 280         pr_debug("%s(key=%ld)\n", __func__, inode->i_ino);
 281         retval = -EIO;
 282         bh = affs_bread(sb, (u32)(long)dentry->d_fsdata);
 283         if (!bh)
 284                 goto done;
 285
 286         affs_lock_link(inode);
 287         affs_lock_dir(dir);
 288         switch (be32_to_cpu(AFFS_TAIL(sb, bh)->stype)) {
 289         case ST_USERDIR:
 290                 /* if we ever want to support links to dirs
 291                  * i_hash_lock of the inode must only be
 292                  * taken after some checks
 293                  */
 294                 affs_lock_dir(inode);
 295                 retval = affs_empty_dir(inode);
 296                 affs_unlock_dir(inode);
 297                 if (retval)
 298                         goto done_unlock;
 299                 break;
 300         default:
 301                 break;
 302         }
 303
 304         retval = affs_remove_hash(dir, bh);
 305         if (retval)
 306                 goto done_unlock;
 307         mark_buffer_dirty_inode(bh, inode);
 308
 309         affs_unlock_dir(dir);
 310
 311         if (inode->i_nlink > 1)
 312                 retval = affs_remove_link(dentry);
 313         else
 314                 clear_nlink(inode);
 315         affs_unlock_link(inode);
 316         inode->i_ctime = CURRENT_TIME_SEC;
 317         mark_inode_dirty(inode);
 318
 319 done:
 320         affs_brelse(bh);
 321         return retval;
 322
 323 done_unlock:
 324         affs_unlock_dir(dir);
 325         affs_unlock_link(inode);
 326         goto done;
 327 }
 328
 329 /* Checksum a block, do various consistency checks and optionally return
 330    the blocks type number.  DATA points to the block.  If their pointers
 331    are non-null, *PTYPE and *STYPE are set to the primary and secondary
 332    block types respectively, *HASHSIZE is set to the size of the hashtable
 333    (which lets us calculate the block size).
 334    Returns non-zero if the block is not consistent. */
 335
 336 u32
 337 affs_checksum_block(struct super_block *sb, struct buffer_head *bh)
 338 {
 339         __be32 *ptr = (__be32 *)bh->b_data;
 340         u32 sum;
 341         int bsize;
 342
 343         sum = 0;
 344         for (bsize = sb->s_blocksize / sizeof(__be32); bsize > 0; bsize--)
 345                 sum += be32_to_cpu(*ptr++);
 346         return sum;
 347 }
 348
 349 /*
 350  * Calculate the checksum of a disk block and store it
 351  * at the indicated position.
 352  */
 353
 354 void
 355 affs_fix_checksum(struct super_block *sb, struct buffer_head *bh)
 356 {
 357         int cnt = sb->s_blocksize / sizeof(__be32);
 358         __be32 *ptr = (__be32 *)bh->b_data;
 359         u32 checksum;
 360         __be32 *checksumptr;
 361
 362         checksumptr = ptr + 5;
 363         *checksumptr = 0;
 364         for (checksum = 0; cnt > 0; ptr++, cnt--)
 365                 checksum += be32_to_cpu(*ptr);
 366         *checksumptr = cpu_to_be32(-checksum);
 367 }
 368
 369 void
 370 secs_to_datestamp(time64_t secs, struct affs_date *ds)
 371 {
 372         u32      days;
 373         u32      minute;
 374         s32      rem;
 375
 376         secs -= sys_tz.tz_minuteswest * 60 + ((8 * 365 + 2) * 24 * 60 * 60);
 377         if (secs < 0)
 378                 secs = 0;
 379         days    = div_s64_rem(secs, 86400, &rem);
 380         minute  = rem / 60;
 381         rem    -= minute * 60;
 382
 383         ds->days = cpu_to_be32(days);
 384         ds->mins = cpu_to_be32(minute);
 385         ds->ticks = cpu_to_be32(rem * 50);
 386 }
 387
 388 umode_t
 389 prot_to_mode(u32 prot)
 390 {
 391         umode_t mode = 0;
 392
 393         if (!(prot & FIBF_NOWRITE))
 394                 mode |= S_IWUSR;
 395         if (!(prot & FIBF_NOREAD))
 396                 mode |= S_IRUSR;
 397         if (!(prot & FIBF_NOEXECUTE))
 398                 mode |= S_IXUSR;
 399         if (prot & FIBF_GRP_WRITE)
 400                 mode |= S_IWGRP;
 401         if (prot & FIBF_GRP_READ)
 402                 mode |= S_IRGRP;
 403         if (prot & FIBF_GRP_EXECUTE)
 404                 mode |= S_IXGRP;
 405         if (prot & FIBF_OTR_WRITE)
 406                 mode |= S_IWOTH;
 407         if (prot & FIBF_OTR_READ)
 408                 mode |= S_IROTH;
 409         if (prot & FIBF_OTR_EXECUTE)
 410                 mode |= S_IXOTH;
 411
 412         return mode;
 413 }
 414
 415 void
 416 mode_to_prot(struct inode *inode)
 417 {
 418         u32 prot = AFFS_I(inode)->i_protect;
 419         umode_t mode = inode->i_mode;
 420
 421         if (!(mode & S_IXUSR))
 422                 prot |= FIBF_NOEXECUTE;
 423         if (!(mode & S_IRUSR))
 424                 prot |= FIBF_NOREAD;
 425         if (!(mode & S_IWUSR))
 426                 prot |= FIBF_NOWRITE;
 427         if (mode & S_IXGRP)
 428                 prot |= FIBF_GRP_EXECUTE;
 429         if (mode & S_IRGRP)
 430                 prot |= FIBF_GRP_READ;
 431         if (mode & S_IWGRP)
 432                 prot |= FIBF_GRP_WRITE;
 433         if (mode & S_IXOTH)
 434                 prot |= FIBF_OTR_EXECUTE;
 435         if (mode & S_IROTH)
 436                 prot |= FIBF_OTR_READ;
 437         if (mode & S_IWOTH)
 438                 prot |= FIBF_OTR_WRITE;
 439
 440         AFFS_I(inode)->i_protect = prot;
 441 }
 442
 443 void
 444 affs_error(struct super_block *sb, const char *function, const char *fmt, ...)
 445 {
 446         struct va_format vaf;
 447         va_list args;
 448
 449         va_start(args, fmt);
 450         vaf.fmt = fmt;
 451         vaf.va = &args;
 452         pr_crit("error (device %s): %s(): %pV\n", sb->s_id, function, &vaf);
 453         if (!(sb->s_flags & MS_RDONLY))
 454                 pr_warn("Remounting filesystem read-only\n");
 455         sb->s_flags |= MS_RDONLY;
 456         va_end(args);
 457 }
 458
 459 void
 460 affs_warning(struct super_block *sb, const char *function, const char *fmt, ...)
 461 {
 462         struct va_format vaf;
 463         va_list args;
 464
 465         va_start(args, fmt);
 466         vaf.fmt = fmt;
 467         vaf.va = &args;
 468         pr_warn("(device %s): %s(): %pV\n", sb->s_id, function, &vaf);
 469         va_end(args);
 470 }
 471
 472 bool
 473 affs_nofilenametruncate(const struct dentry *dentry)
 474 {
 475         struct inode *inode = d_inode(dentry);
 476
 477         return affs_test_opt(AFFS_SB(inode->i_sb)->s_flags, SF_NO_TRUNCATE);
 478 }
 479
 480 /* Check if the name is valid for a affs object. */
 481
 482 int
 483 affs_check_name(const unsigned char *name, int len, bool notruncate)
 484 {
 485         int      i;
 486
 487         if (len > AFFSNAMEMAX) {
 488                 if (notruncate)
 489                         return -ENAMETOOLONG;
 490                 len = AFFSNAMEMAX;
 491         }
 492         for (i = 0; i < len; i++) {
 493                 if (name[i] < ' ' || name[i] == ':'
 494                     || (name[i] > 0x7e && name[i] < 0xa0))
 495                         return -EINVAL;
 496         }
 497
 498         return 0;
 499 }
 500
 501 /* This function copies name to bstr, with at most 30
 502  * characters length. The bstr will be prepended by
 503  * a length byte.
 504  * NOTE: The name will must be already checked by
 505  *       affs_check_name()!
 506  */
 507
 508 int
 509 affs_copy_name(unsigned char *bstr, struct dentry *dentry)
 510 {
 511         u32 len = min(dentry->d_name.len, AFFSNAMEMAX);
 512
 513         *bstr++ = len;
 514         memcpy(bstr, dentry->d_name.name, len);
 515         return len;
 516 }