fs/affs/amigaffs.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  linux/fs/affs/amigaffs.c
   4  *
   5  *  (c) 1996  Hans-Joachim Widmaier - Rewritten
   6  *
   7  *  (C) 1993  Ray Burr - Amiga FFS filesystem.
   8  *
   9  *  Please send bug reports to: hjw@zvw.de
  10  */
  11
  12 #include <linux/math64.h>
  13 #include "affs.h"
  14
  15 /*
  16  * Functions for accessing Amiga-FFS structures.
  17  */
  18
  19
  20 /* Insert a header block bh into the directory dir
  21  * caller must hold AFFS_DIR->i_hash_lock!
  22  */
  23
  24 int
  25 affs_insert_hash(struct inode *dir, struct buffer_head *bh)
  26 {
  27         struct super_block *sb = dir->i_sb;
  28         struct buffer_head *dir_bh;
  29         u32 ino, hash_ino;
  30         int offset;
  31
  32         ino = bh->b_blocknr;
  33         offset = affs_hash_name(sb, AFFS_TAIL(sb, bh)->name + 1, AFFS_TAIL(sb, bh)->name[0]);
  34
  35         pr_debug("%s(dir=%lu, ino=%d)\n", __func__, dir->i_ino, ino);
  36
  37         dir_bh = affs_bread(sb, dir->i_ino);
  38         if (!dir_bh)
  39                 return -EIO;
  40
  41         hash_ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[offset]);
  42         while (hash_ino) {
  43                 affs_brelse(dir_bh);
  44                 dir_bh = affs_bread(sb, hash_ino);
  45                 if (!dir_bh)
  46                         return -EIO;
  47                 hash_ino = be32_to_cpu(AFFS_TAIL(sb, dir_bh)->hash_chain);
  48         }
  49         AFFS_TAIL(sb, bh)->parent = cpu_to_be32(dir->i_ino);
  50         AFFS_TAIL(sb, bh)->hash_chain = 0;
  51         affs_fix_checksum(sb, bh);
  52
  53         if (dir->i_ino == dir_bh->b_blocknr)
  54                 AFFS_HEAD(dir_bh)->table[offset] = cpu_to_be32(ino);
  55         else
  56                 AFFS_TAIL(sb, dir_bh)->hash_chain = cpu_to_be32(ino);
  57
  58         affs_adjust_checksum(dir_bh, ino);
  59         mark_buffer_dirty_inode(dir_bh, dir);
  60         affs_brelse(dir_bh);
  61
  62         dir->i_mtime = dir->i_ctime = current_time(dir);
  63         dir->i_version++;
  64         mark_inode_dirty(dir);
  65
  66         return 0;
  67 }
  68
  69 /* Remove a header block from its directory.
  70  * caller must hold AFFS_DIR->i_hash_lock!
  71  */
  72
  73 int
  74 affs_remove_hash(struct inode *dir, struct buffer_head *rem_bh)
  75 {
  76         struct super_block *sb;
  77         struct buffer_head *bh;
  78         u32 rem_ino, hash_ino;
  79         __be32 ino;
  80         int offset, retval;
  81
  82         sb = dir->i_sb;
  83         rem_ino = rem_bh->b_blocknr;
  84         offset = affs_hash_name(sb, AFFS_TAIL(sb, rem_bh)->name+1, AFFS_TAIL(sb, rem_bh)->name[0]);
  85         pr_debug("%s(dir=%lu, ino=%d, hashval=%d)\n", __func__, dir->i_ino,
  86                  rem_ino, offset);
  87
  88         bh = affs_bread(sb, dir->i_ino);
  89         if (!bh)
  90                 return -EIO;
  91
  92         retval = -ENOENT;
  93         hash_ino = be32_to_cpu(AFFS_HEAD(bh)->table[offset]);
  94         while (hash_ino) {
  95                 if (hash_ino == rem_ino) {
  96                         ino = AFFS_TAIL(sb, rem_bh)->hash_chain;
  97                         if (dir->i_ino == bh->b_blocknr)
  98                                 AFFS_HEAD(bh)->table[offset] = ino;
  99                         else
 100                                 AFFS_TAIL(sb, bh)->hash_chain = ino;
 101                         affs_adjust_checksum(bh, be32_to_cpu(ino) - hash_ino);
 102                         mark_buffer_dirty_inode(bh, dir);
 103                         AFFS_TAIL(sb, rem_bh)->parent = 0;
 104                         retval = 0;
 105                         break;
 106                 }
 107                 affs_brelse(bh);
 108                 bh = affs_bread(sb, hash_ino);
 109                 if (!bh)
 110                         return -EIO;
 111                 hash_ino = be32_to_cpu(AFFS_TAIL(sb, bh)->hash_chain);
 112         }
 113
 114         affs_brelse(bh);
 115
 116         dir->i_mtime = dir->i_ctime = current_time(dir);
 117         dir->i_version++;
 118         mark_inode_dirty(dir);
 119
 120         return retval;
 121 }
 122
 123 static void
 124 affs_fix_dcache(struct inode *inode, u32 entry_ino)
 125 {
 126         struct dentry *dentry;
 127         spin_lock(&inode->i_lock);
 128         hlist_for_each_entry(dentry, &inode->i_dentry, d_u.d_alias) {
 129                 if (entry_ino == (u32)(long)dentry->d_fsdata) {
 130                         dentry->d_fsdata = (void *)inode->i_ino;
 131                         break;
 132                 }
 133         }
 134         spin_unlock(&inode->i_lock);
 135 }
 136
 137
 138 /* Remove header from link chain */
 139
 140 static int
 141 affs_remove_link(struct dentry *dentry)
 142 {
 143         struct inode *dir, *inode = d_inode(dentry);
 144         struct super_block *sb = inode->i_sb;
 145         struct buffer_head *bh, *link_bh = NULL;
 146         u32 link_ino, ino;
 147         int retval;
 148
 149         pr_debug("%s(key=%ld)\n", __func__, inode->i_ino);
 150         retval = -EIO;
 151         bh = affs_bread(sb, inode->i_ino);
 152         if (!bh)
 153                 goto done;
 154
 155         link_ino = (u32)(long)dentry->d_fsdata;
 156         if (inode->i_ino == link_ino) {
 157                 /* we can't remove the head of the link, as its blocknr is still used as ino,
 158                  * so we remove the block of the first link instead.
 159                  */
 160                 link_ino = be32_to_cpu(AFFS_TAIL(sb, bh)->link_chain);
 161                 link_bh = affs_bread(sb, link_ino);
 162                 if (!link_bh)
 163                         goto done;
 164
 165                 dir = affs_iget(sb, be32_to_cpu(AFFS_TAIL(sb, link_bh)->parent));
 166                 if (IS_ERR(dir)) {
 167                         retval = PTR_ERR(dir);
 168                         goto done;
 169                 }
 170
 171                 affs_lock_dir(dir);
 172                 /*
 173                  * if there's a dentry for that block, make it
 174                  * refer to inode itself.
 175                  */
 176                 affs_fix_dcache(inode, link_ino);
 177                 retval = affs_remove_hash(dir, link_bh);
 178                 if (retval) {
 179                         affs_unlock_dir(dir);
 180                         goto done;
 181                 }
 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                         affs_unlock_dir(dir);
 188                         goto done;
 189                 }
 190                 mark_buffer_dirty_inode(bh, inode);
 191
 192                 affs_unlock_dir(dir);
 193                 iput(dir);
 194         } else {
 195                 link_bh = affs_bread(sb, link_ino);
 196                 if (!link_bh)
 197                         goto done;
 198         }
 199
 200         while ((ino = be32_to_cpu(AFFS_TAIL(sb, bh)->link_chain)) != 0) {
 201                 if (ino == link_ino) {
 202                         __be32 ino2 = AFFS_TAIL(sb, link_bh)->link_chain;
 203                         AFFS_TAIL(sb, bh)->link_chain = ino2;
 204                         affs_adjust_checksum(bh, be32_to_cpu(ino2) - link_ino);
 205                         mark_buffer_dirty_inode(bh, inode);
 206                         retval = 0;
 207                         /* Fix the link count, if bh is a normal header block without links */
 208                         switch (be32_to_cpu(AFFS_TAIL(sb, bh)->stype)) {
 209                         case ST_LINKDIR:
 210                         case ST_LINKFILE:
 211                                 break;
 212                         default:
 213                                 if (!AFFS_TAIL(sb, bh)->link_chain)
 214                                         set_nlink(inode, 1);
 215                         }
 216                         affs_free_block(sb, link_ino);
 217                         goto done;
 218                 }
 219                 affs_brelse(bh);
 220                 bh = affs_bread(sb, ino);
 221                 if (!bh)
 222                         goto done;
 223         }
 224         retval = -ENOENT;
 225 done:
 226         affs_brelse(link_bh);
 227         affs_brelse(bh);
 228         return retval;
 229 }
 230
 231
 232 static int
 233 affs_empty_dir(struct inode *inode)
 234 {
 235         struct super_block *sb = inode->i_sb;
 236         struct buffer_head *bh;
 237         int retval, size;
 238
 239         retval = -EIO;
 240         bh = affs_bread(sb, inode->i_ino);
 241         if (!bh)
 242                 goto done;
 243
 244         retval = -ENOTEMPTY;
 245         for (size = AFFS_SB(sb)->s_hashsize - 1; size >= 0; size--)
 246                 if (AFFS_HEAD(bh)->table[size])
 247                         goto not_empty;
 248         retval = 0;
 249 not_empty:
 250         affs_brelse(bh);
 251 done:
 252         return retval;
 253 }
 254
 255
 256 /* Remove a filesystem object. If the object to be removed has
 257  * links to it, one of the links must be changed to inherit
 258  * the file or directory. As above, any inode will do.
 259  * The buffer will not be freed. If the header is a link, the
 260  * block will be marked as free.
 261  * This function returns a negative error number in case of
 262  * an error, else 0 if the inode is to be deleted or 1 if not.
 263  */
 264
 265 int
 266 affs_remove_header(struct dentry *dentry)
 267 {
 268         struct super_block *sb;
 269         struct inode *inode, *dir;
 270         struct buffer_head *bh = NULL;
 271         int retval;
 272
 273         dir = d_inode(dentry->d_parent);
 274         sb = dir->i_sb;
 275
 276         retval = -ENOENT;
 277         inode = d_inode(dentry);
 278         if (!inode)
 279                 goto done;
 280
 281         pr_debug("%s(key=%ld)\n", __func__, inode->i_ino);
 282         retval = -EIO;
 283         bh = affs_bread(sb, (u32)(long)dentry->d_fsdata);
 284         if (!bh)
 285                 goto done;
 286
 287         affs_lock_link(inode);
 288         affs_lock_dir(dir);
 289         switch (be32_to_cpu(AFFS_TAIL(sb, bh)->stype)) {
 290         case ST_USERDIR:
 291                 /* if we ever want to support links to dirs
 292                  * i_hash_lock of the inode must only be
 293                  * taken after some checks
 294                  */
 295                 affs_lock_dir(inode);
 296                 retval = affs_empty_dir(inode);
 297                 affs_unlock_dir(inode);
 298                 if (retval)
 299                         goto done_unlock;
 300                 break;
 301         default:
 302                 break;
 303         }
 304
 305         retval = affs_remove_hash(dir, bh);
 306         if (retval)
 307                 goto done_unlock;
 308         mark_buffer_dirty_inode(bh, inode);
 309
 310         affs_unlock_dir(dir);
 311
 312         if (inode->i_nlink > 1)
 313                 retval = affs_remove_link(dentry);
 314         else
 315                 clear_nlink(inode);
 316         affs_unlock_link(inode);
 317         inode->i_ctime = current_time(inode);
 318         mark_inode_dirty(inode);
 319
 320 done:
 321         affs_brelse(bh);
 322         return retval;
 323
 324 done_unlock:
 325         affs_unlock_dir(dir);
 326         affs_unlock_link(inode);
 327         goto done;
 328 }
 329
 330 /* Checksum a block, do various consistency checks and optionally return
 331    the blocks type number.  DATA points to the block.  If their pointers
 332    are non-null, *PTYPE and *STYPE are set to the primary and secondary
 333    block types respectively, *HASHSIZE is set to the size of the hashtable
 334    (which lets us calculate the block size).
 335    Returns non-zero if the block is not consistent. */
 336
 337 u32
 338 affs_checksum_block(struct super_block *sb, struct buffer_head *bh)
 339 {
 340         __be32 *ptr = (__be32 *)bh->b_data;
 341         u32 sum;
 342         int bsize;
 343
 344         sum = 0;
 345         for (bsize = sb->s_blocksize / sizeof(__be32); bsize > 0; bsize--)
 346                 sum += be32_to_cpu(*ptr++);
 347         return sum;
 348 }
 349
 350 /*
 351  * Calculate the checksum of a disk block and store it
 352  * at the indicated position.
 353  */
 354
 355 void
 356 affs_fix_checksum(struct super_block *sb, struct buffer_head *bh)
 357 {
 358         int cnt = sb->s_blocksize / sizeof(__be32);
 359         __be32 *ptr = (__be32 *)bh->b_data;
 360         u32 checksum;
 361         __be32 *checksumptr;
 362
 363         checksumptr = ptr + 5;
 364         *checksumptr = 0;
 365         for (checksum = 0; cnt > 0; ptr++, cnt--)
 366                 checksum += be32_to_cpu(*ptr);
 367         *checksumptr = cpu_to_be32(-checksum);
 368 }
 369
 370 void
 371 affs_secs_to_datestamp(time64_t secs, struct affs_date *ds)
 372 {
 373         u32      days;
 374         u32      minute;
 375         s32      rem;
 376
 377         secs -= sys_tz.tz_minuteswest * 60 + ((8 * 365 + 2) * 24 * 60 * 60);
 378         if (secs < 0)
 379                 secs = 0;
 380         days    = div_s64_rem(secs, 86400, &rem);
 381         minute  = rem / 60;
 382         rem    -= minute * 60;
 383
 384         ds->days = cpu_to_be32(days);
 385         ds->mins = cpu_to_be32(minute);
 386         ds->ticks = cpu_to_be32(rem * 50);
 387 }
 388
 389 umode_t
 390 affs_prot_to_mode(u32 prot)
 391 {
 392         umode_t mode = 0;
 393
 394         if (!(prot & FIBF_NOWRITE))
 395                 mode |= 0200;
 396         if (!(prot & FIBF_NOREAD))
 397                 mode |= 0400;
 398         if (!(prot & FIBF_NOEXECUTE))
 399                 mode |= 0100;
 400         if (prot & FIBF_GRP_WRITE)
 401                 mode |= 0020;
 402         if (prot & FIBF_GRP_READ)
 403                 mode |= 0040;
 404         if (prot & FIBF_GRP_EXECUTE)
 405                 mode |= 0010;
 406         if (prot & FIBF_OTR_WRITE)
 407                 mode |= 0002;
 408         if (prot & FIBF_OTR_READ)
 409                 mode |= 0004;
 410         if (prot & FIBF_OTR_EXECUTE)
 411                 mode |= 0001;
 412
 413         return mode;
 414 }
 415
 416 void
 417 affs_mode_to_prot(struct inode *inode)
 418 {
 419         u32 prot = AFFS_I(inode)->i_protect;
 420         umode_t mode = inode->i_mode;
 421
 422         if (!(mode & 0100))
 423                 prot |= FIBF_NOEXECUTE;
 424         if (!(mode & 0400))
 425                 prot |= FIBF_NOREAD;
 426         if (!(mode & 0200))
 427                 prot |= FIBF_NOWRITE;
 428         if (mode & 0010)
 429                 prot |= FIBF_GRP_EXECUTE;
 430         if (mode & 0040)
 431                 prot |= FIBF_GRP_READ;
 432         if (mode & 0020)
 433                 prot |= FIBF_GRP_WRITE;
 434         if (mode & 0001)
 435                 prot |= FIBF_OTR_EXECUTE;
 436         if (mode & 0004)
 437                 prot |= FIBF_OTR_READ;
 438         if (mode & 0002)
 439                 prot |= FIBF_OTR_WRITE;
 440
 441         AFFS_I(inode)->i_protect = prot;
 442 }
 443
 444 void
 445 affs_error(struct super_block *sb, const char *function, const char *fmt, ...)
 446 {
 447         struct va_format vaf;
 448         va_list args;
 449
 450         va_start(args, fmt);
 451         vaf.fmt = fmt;
 452         vaf.va = &args;
 453         pr_crit("error (device %s): %s(): %pV\n", sb->s_id, function, &vaf);
 454         if (!sb_rdonly(sb))
 455                 pr_warn("Remounting filesystem read-only\n");
 456         sb->s_flags |= SB_RDONLY;
 457         va_end(args);
 458 }
 459
 460 void
 461 affs_warning(struct super_block *sb, const char *function, const char *fmt, ...)
 462 {
 463         struct va_format vaf;
 464         va_list args;
 465
 466         va_start(args, fmt);
 467         vaf.fmt = fmt;
 468         vaf.va = &args;
 469         pr_warn("(device %s): %s(): %pV\n", sb->s_id, function, &vaf);
 470         va_end(args);
 471 }
 472
 473 bool
 474 affs_nofilenametruncate(const struct dentry *dentry)
 475 {
 476         return affs_test_opt(AFFS_SB(dentry->d_sb)->s_flags, SF_NO_TRUNCATE);
 477 }
 478
 479 /* Check if the name is valid for a affs object. */
 480
 481 int
 482 affs_check_name(const unsigned char *name, int len, bool notruncate)
 483 {
 484         int      i;
 485
 486         if (len > AFFSNAMEMAX) {
 487                 if (notruncate)
 488                         return -ENAMETOOLONG;
 489                 len = AFFSNAMEMAX;
 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         u32 len = min(dentry->d_name.len, AFFSNAMEMAX);
 511
 512         *bstr++ = len;
 513         memcpy(bstr, dentry->d_name.name, len);
 514         return len;
 515 }