fs/affs/amigaffs.c

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This source file includes following definitions.
affs_insert_hash
affs_remove_hash
affs_fix_dcache
affs_remove_link
affs_empty_dir
affs_remove_header
affs_checksum_block
affs_fix_checksum
affs_secs_to_datestamp
affs_prot_to_mode
affs_mode_to_prot
affs_error
affs_warning
affs_nofilenametruncate
affs_check_name
affs_copy_name
   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 <linux/iversion.h>
  14 #include "affs.h"
  15 
  16 /*
  17  * Functions for accessing Amiga-FFS structures.
  18  */
  19 
  20 
  21 /* Insert a header block bh into the directory dir
  22  * caller must hold AFFS_DIR->i_hash_lock!
  23  */
  24 
  25 int
  26 affs_insert_hash(struct inode *dir, struct buffer_head *bh)
  27 {
  28         struct super_block *sb = dir->i_sb;
  29         struct buffer_head *dir_bh;
  30         u32 ino, hash_ino;
  31         int offset;
  32 
  33         ino = bh->b_blocknr;
  34         offset = affs_hash_name(sb, AFFS_TAIL(sb, bh)->name + 1, AFFS_TAIL(sb, bh)->name[0]);
  35 
  36         pr_debug("%s(dir=%lu, ino=%d)\n", __func__, dir->i_ino, ino);
  37 
  38         dir_bh = affs_bread(sb, dir->i_ino);
  39         if (!dir_bh)
  40                 return -EIO;
  41 
  42         hash_ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[offset]);
  43         while (hash_ino) {
  44                 affs_brelse(dir_bh);
  45                 dir_bh = affs_bread(sb, hash_ino);
  46                 if (!dir_bh)
  47                         return -EIO;
  48                 hash_ino = be32_to_cpu(AFFS_TAIL(sb, dir_bh)->hash_chain);
  49         }
  50         AFFS_TAIL(sb, bh)->parent = cpu_to_be32(dir->i_ino);
  51         AFFS_TAIL(sb, bh)->hash_chain = 0;
  52         affs_fix_checksum(sb, bh);
  53 
  54         if (dir->i_ino == dir_bh->b_blocknr)
  55                 AFFS_HEAD(dir_bh)->table[offset] = cpu_to_be32(ino);
  56         else
  57                 AFFS_TAIL(sb, dir_bh)->hash_chain = cpu_to_be32(ino);
  58 
  59         affs_adjust_checksum(dir_bh, ino);
  60         mark_buffer_dirty_inode(dir_bh, dir);
  61         affs_brelse(dir_bh);
  62 
  63         dir->i_mtime = dir->i_ctime = current_time(dir);
  64         inode_inc_iversion(dir);
  65         mark_inode_dirty(dir);
  66 
  67         return 0;
  68 }
  69 
  70 /* Remove a header block from its directory.
  71  * caller must hold AFFS_DIR->i_hash_lock!
  72  */
  73 
  74 int
  75 affs_remove_hash(struct inode *dir, struct buffer_head *rem_bh)
  76 {
  77         struct super_block *sb;
  78         struct buffer_head *bh;
  79         u32 rem_ino, hash_ino;
  80         __be32 ino;
  81         int offset, retval;
  82 
  83         sb = dir->i_sb;
  84         rem_ino = rem_bh->b_blocknr;
  85         offset = affs_hash_name(sb, AFFS_TAIL(sb, rem_bh)->name+1, AFFS_TAIL(sb, rem_bh)->name[0]);
  86         pr_debug("%s(dir=%lu, ino=%d, hashval=%d)\n", __func__, dir->i_ino,
  87                  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(dir);
 118         inode_inc_iversion(dir);
 119         mark_inode_dirty(dir);
 120 
 121         return retval;
 122 }
 123 
 124 static void
 125 affs_fix_dcache(struct inode *inode, u32 entry_ino)
 126 {
 127         struct dentry *dentry;
 128         spin_lock(&inode->i_lock);
 129         hlist_for_each_entry(dentry, &inode->i_dentry, d_u.d_alias) {
 130                 if (entry_ino == (u32)(long)dentry->d_fsdata) {
 131                         dentry->d_fsdata = (void *)inode->i_ino;
 132                         break;
 133                 }
 134         }
 135         spin_unlock(&inode->i_lock);
 136 }
 137 
 138 
 139 /* Remove header from link chain */
 140 
 141 static int
 142 affs_remove_link(struct dentry *dentry)
 143 {
 144         struct inode *dir, *inode = d_inode(dentry);
 145         struct super_block *sb = inode->i_sb;
 146         struct buffer_head *bh, *link_bh = NULL;
 147         u32 link_ino, ino;
 148         int retval;
 149 
 150         pr_debug("%s(key=%ld)\n", __func__, inode->i_ino);
 151         retval = -EIO;
 152         bh = affs_bread(sb, inode->i_ino);
 153         if (!bh)
 154                 goto done;
 155 
 156         link_ino = (u32)(long)dentry->d_fsdata;
 157         if (inode->i_ino == link_ino) {
 158                 /* we can't remove the head of the link, as its blocknr is still used as ino,
 159                  * so we remove the block of the first link instead.
 160                  */ 
 161                 link_ino = be32_to_cpu(AFFS_TAIL(sb, bh)->link_chain);
 162                 link_bh = affs_bread(sb, link_ino);
 163                 if (!link_bh)
 164                         goto done;
 165 
 166                 dir = affs_iget(sb, be32_to_cpu(AFFS_TAIL(sb, link_bh)->parent));
 167                 if (IS_ERR(dir)) {
 168                         retval = PTR_ERR(dir);
 169                         goto done;
 170                 }
 171 
 172                 affs_lock_dir(dir);
 173                 /*
 174                  * if there's a dentry for that block, make it
 175                  * refer to inode itself.
 176                  */
 177                 affs_fix_dcache(inode, link_ino);
 178                 retval = affs_remove_hash(dir, link_bh);
 179                 if (retval) {
 180                         affs_unlock_dir(dir);
 181                         goto done;
 182                 }
 183                 mark_buffer_dirty_inode(link_bh, inode);
 184 
 185                 memcpy(AFFS_TAIL(sb, bh)->name, AFFS_TAIL(sb, link_bh)->name, 32);
 186                 retval = affs_insert_hash(dir, bh);
 187                 if (retval) {
 188                         affs_unlock_dir(dir);
 189                         goto done;
 190                 }
 191                 mark_buffer_dirty_inode(bh, inode);
 192 
 193                 affs_unlock_dir(dir);
 194                 iput(dir);
 195         } else {
 196                 link_bh = affs_bread(sb, link_ino);
 197                 if (!link_bh)
 198                         goto done;
 199         }
 200 
 201         while ((ino = be32_to_cpu(AFFS_TAIL(sb, bh)->link_chain)) != 0) {
 202                 if (ino == link_ino) {
 203                         __be32 ino2 = AFFS_TAIL(sb, link_bh)->link_chain;
 204                         AFFS_TAIL(sb, bh)->link_chain = ino2;
 205                         affs_adjust_checksum(bh, be32_to_cpu(ino2) - link_ino);
 206                         mark_buffer_dirty_inode(bh, inode);
 207                         retval = 0;
 208                         /* Fix the link count, if bh is a normal header block without links */
 209                         switch (be32_to_cpu(AFFS_TAIL(sb, bh)->stype)) {
 210                         case ST_LINKDIR:
 211                         case ST_LINKFILE:
 212                                 break;
 213                         default:
 214                                 if (!AFFS_TAIL(sb, bh)->link_chain)
 215                                         set_nlink(inode, 1);
 216                         }
 217                         affs_free_block(sb, link_ino);
 218                         goto done;
 219                 }
 220                 affs_brelse(bh);
 221                 bh = affs_bread(sb, ino);
 222                 if (!bh)
 223                         goto done;
 224         }
 225         retval = -ENOENT;
 226 done:
 227         affs_brelse(link_bh);
 228         affs_brelse(bh);
 229         return retval;
 230 }
 231 
 232 
 233 static int
 234 affs_empty_dir(struct inode *inode)
 235 {
 236         struct super_block *sb = inode->i_sb;
 237         struct buffer_head *bh;
 238         int retval, size;
 239 
 240         retval = -EIO;
 241         bh = affs_bread(sb, inode->i_ino);
 242         if (!bh)
 243                 goto done;
 244 
 245         retval = -ENOTEMPTY;
 246         for (size = AFFS_SB(sb)->s_hashsize - 1; size >= 0; size--)
 247                 if (AFFS_HEAD(bh)->table[size])
 248                         goto not_empty;
 249         retval = 0;
 250 not_empty:
 251         affs_brelse(bh);
 252 done:
 253         return retval;
 254 }
 255 
 256 
 257 /* Remove a filesystem object. If the object to be removed has
 258  * links to it, one of the links must be changed to inherit
 259  * the file or directory. As above, any inode will do.
 260  * The buffer will not be freed. If the header is a link, the
 261  * block will be marked as free.
 262  * This function returns a negative error number in case of
 263  * an error, else 0 if the inode is to be deleted or 1 if not.
 264  */
 265 
 266 int
 267 affs_remove_header(struct dentry *dentry)
 268 {
 269         struct super_block *sb;
 270         struct inode *inode, *dir;
 271         struct buffer_head *bh = NULL;
 272         int retval;
 273 
 274         dir = d_inode(dentry->d_parent);
 275         sb = dir->i_sb;
 276 
 277         retval = -ENOENT;
 278         inode = d_inode(dentry);
 279         if (!inode)
 280                 goto done;
 281 
 282         pr_debug("%s(key=%ld)\n", __func__, inode->i_ino);
 283         retval = -EIO;
 284         bh = affs_bread(sb, (u32)(long)dentry->d_fsdata);
 285         if (!bh)
 286                 goto done;
 287 
 288         affs_lock_link(inode);
 289         affs_lock_dir(dir);
 290         switch (be32_to_cpu(AFFS_TAIL(sb, bh)->stype)) {
 291         case ST_USERDIR:
 292                 /* if we ever want to support links to dirs
 293                  * i_hash_lock of the inode must only be
 294                  * taken after some checks
 295                  */
 296                 affs_lock_dir(inode);
 297                 retval = affs_empty_dir(inode);
 298                 affs_unlock_dir(inode);
 299                 if (retval)
 300                         goto done_unlock;
 301                 break;
 302         default:
 303                 break;
 304         }
 305 
 306         retval = affs_remove_hash(dir, bh);
 307         if (retval)
 308                 goto done_unlock;
 309         mark_buffer_dirty_inode(bh, inode);
 310 
 311         affs_unlock_dir(dir);
 312 
 313         if (inode->i_nlink > 1)
 314                 retval = affs_remove_link(dentry);
 315         else
 316                 clear_nlink(inode);
 317         affs_unlock_link(inode);
 318         inode->i_ctime = current_time(inode);
 319         mark_inode_dirty(inode);
 320 
 321 done:
 322         affs_brelse(bh);
 323         return retval;
 324 
 325 done_unlock:
 326         affs_unlock_dir(dir);
 327         affs_unlock_link(inode);
 328         goto done;
 329 }
 330 
 331 /* Checksum a block, do various consistency checks and optionally return
 332    the blocks type number.  DATA points to the block.  If their pointers
 333    are non-null, *PTYPE and *STYPE are set to the primary and secondary
 334    block types respectively, *HASHSIZE is set to the size of the hashtable
 335    (which lets us calculate the block size).
 336    Returns non-zero if the block is not consistent. */
 337 
 338 u32
 339 affs_checksum_block(struct super_block *sb, struct buffer_head *bh)
 340 {
 341         __be32 *ptr = (__be32 *)bh->b_data;
 342         u32 sum;
 343         int bsize;
 344 
 345         sum = 0;
 346         for (bsize = sb->s_blocksize / sizeof(__be32); bsize > 0; bsize--)
 347                 sum += be32_to_cpu(*ptr++);
 348         return sum;
 349 }
 350 
 351 /*
 352  * Calculate the checksum of a disk block and store it
 353  * at the indicated position.
 354  */
 355 
 356 void
 357 affs_fix_checksum(struct super_block *sb, struct buffer_head *bh)
 358 {
 359         int cnt = sb->s_blocksize / sizeof(__be32);
 360         __be32 *ptr = (__be32 *)bh->b_data;
 361         u32 checksum;
 362         __be32 *checksumptr;
 363 
 364         checksumptr = ptr + 5;
 365         *checksumptr = 0;
 366         for (checksum = 0; cnt > 0; ptr++, cnt--)
 367                 checksum += be32_to_cpu(*ptr);
 368         *checksumptr = cpu_to_be32(-checksum);
 369 }
 370 
 371 void
 372 affs_secs_to_datestamp(time64_t secs, struct affs_date *ds)
 373 {
 374         u32      days;
 375         u32      minute;
 376         s32      rem;
 377 
 378         secs -= sys_tz.tz_minuteswest * 60 + AFFS_EPOCH_DELTA;
 379         if (secs < 0)
 380                 secs = 0;
 381         days    = div_s64_rem(secs, 86400, &rem);
 382         minute  = rem / 60;
 383         rem    -= minute * 60;
 384 
 385         ds->days = cpu_to_be32(days);
 386         ds->mins = cpu_to_be32(minute);
 387         ds->ticks = cpu_to_be32(rem * 50);
 388 }
 389 
 390 umode_t
 391 affs_prot_to_mode(u32 prot)
 392 {
 393         umode_t mode = 0;
 394 
 395         if (!(prot & FIBF_NOWRITE))
 396                 mode |= 0200;
 397         if (!(prot & FIBF_NOREAD))
 398                 mode |= 0400;
 399         if (!(prot & FIBF_NOEXECUTE))
 400                 mode |= 0100;
 401         if (prot & FIBF_GRP_WRITE)
 402                 mode |= 0020;
 403         if (prot & FIBF_GRP_READ)
 404                 mode |= 0040;
 405         if (prot & FIBF_GRP_EXECUTE)
 406                 mode |= 0010;
 407         if (prot & FIBF_OTR_WRITE)
 408                 mode |= 0002;
 409         if (prot & FIBF_OTR_READ)
 410                 mode |= 0004;
 411         if (prot & FIBF_OTR_EXECUTE)
 412                 mode |= 0001;
 413 
 414         return mode;
 415 }
 416 
 417 void
 418 affs_mode_to_prot(struct inode *inode)
 419 {
 420         u32 prot = AFFS_I(inode)->i_protect;
 421         umode_t mode = inode->i_mode;
 422 
 423         if (!(mode & 0100))
 424                 prot |= FIBF_NOEXECUTE;
 425         if (!(mode & 0400))
 426                 prot |= FIBF_NOREAD;
 427         if (!(mode & 0200))
 428                 prot |= FIBF_NOWRITE;
 429         if (mode & 0010)
 430                 prot |= FIBF_GRP_EXECUTE;
 431         if (mode & 0040)
 432                 prot |= FIBF_GRP_READ;
 433         if (mode & 0020)
 434                 prot |= FIBF_GRP_WRITE;
 435         if (mode & 0001)
 436                 prot |= FIBF_OTR_EXECUTE;
 437         if (mode & 0004)
 438                 prot |= FIBF_OTR_READ;
 439         if (mode & 0002)
 440                 prot |= FIBF_OTR_WRITE;
 441 
 442         AFFS_I(inode)->i_protect = prot;
 443 }
 444 
 445 void
 446 affs_error(struct super_block *sb, const char *function, const char *fmt, ...)
 447 {
 448         struct va_format vaf;
 449         va_list args;
 450 
 451         va_start(args, fmt);
 452         vaf.fmt = fmt;
 453         vaf.va = &args;
 454         pr_crit("error (device %s): %s(): %pV\n", sb->s_id, function, &vaf);
 455         if (!sb_rdonly(sb))
 456                 pr_warn("Remounting filesystem read-only\n");
 457         sb->s_flags |= SB_RDONLY;
 458         va_end(args);
 459 }
 460 
 461 void
 462 affs_warning(struct super_block *sb, const char *function, const char *fmt, ...)
 463 {
 464         struct va_format vaf;
 465         va_list args;
 466 
 467         va_start(args, fmt);
 468         vaf.fmt = fmt;
 469         vaf.va = &args;
 470         pr_warn("(device %s): %s(): %pV\n", sb->s_id, function, &vaf);
 471         va_end(args);
 472 }
 473 
 474 bool
 475 affs_nofilenametruncate(const struct dentry *dentry)
 476 {
 477         return affs_test_opt(AFFS_SB(dentry->d_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 }
/* [<][>][^][v][top][bottom][index][help] */
root/fs/affs/amigaffs.c

DEFINITIONS
