root/fs/minix/namei.c

/* */

DEFINITIONS

1. namecompare
2. minix_match
3. minix_find_entry
4. minix_lookup
5. minix_add_entry
6. minix_create
7. minix_mknod
8. minix_mkdir
9. empty_dir
10. minix_rmdir
11. minix_unlink
12. minix_symlink
13. minix_link
14. subdir
15. do_minix_rename
16. minix_rename

   1 /*
   2  *  linux/fs/minix/namei.c
   3  *
   4  *  Copyright (C) 1991, 1992  Linus Torvalds
   5  */
   6 
   7 #ifdef MODULE
   8 #include <linux/module.h>
   9 #endif
  10 
  11 #include <linux/sched.h>
  12 #include <linux/minix_fs.h>
  13 #include <linux/kernel.h>
  14 #include <linux/string.h>
  15 #include <linux/stat.h>
  16 #include <linux/fcntl.h>
  17 #include <linux/errno.h>
  18 
  19 #include <asm/segment.h>
  20 
  21 /*
  22  * comment out this line if you want names > info->s_namelen chars to be
  23  * truncated. Else they will be disallowed (ENAMETOOLONG).
  24  */
  25 /* #define NO_TRUNCATE */
  26 
  27 static inline int namecompare(int len, int maxlen,
     /*  */
  28         const char * name, const char * buffer)
  29 {
  30         if (len > maxlen)
  31                 return 0;
  32         if (len < maxlen && buffer[len])
  33                 return 0;
  34         return !memcmp(name, buffer, len);
  35 }
  36 
  37 /*
  38  * ok, we cannot use strncmp, as the name is not in our data space.
  39  * Thus we'll have to use minix_match. No big problem. Match also makes
  40  * some sanity tests.
  41  *
  42  * NOTE! unlike strncmp, minix_match returns 1 for success, 0 for failure.
  43  */
  44 static int minix_match(int len, const char * name,
     /*  */
  45         struct buffer_head * bh, unsigned long * offset,
  46         struct minix_sb_info * info)
  47 {
  48         struct minix_dir_entry * de;
  49 
  50         de = (struct minix_dir_entry *) (bh->b_data + *offset);
  51         *offset += info->s_dirsize;
  52         if (!de->inode || len > info->s_namelen)
  53                 return 0;
  54         /* "" means "." ---> so paths like "/usr/lib//libc.a" work */
  55         if (!len && (de->name[0]=='.') && (de->name[1]=='\0'))
  56                 return 1;
  57         return namecompare(len,info->s_namelen,name,de->name);
  58 }
  59 
  60 /*
  61  *      minix_find_entry()
  62  *
  63  * finds an entry in the specified directory with the wanted name. It
  64  * returns the cache buffer in which the entry was found, and the entry
  65  * itself (as a parameter - res_dir). It does NOT read the inode of the
  66  * entry - you'll have to do that yourself if you want to.
  67  */
  68 static struct buffer_head * minix_find_entry(struct inode * dir,
     /*  */
  69         const char * name, int namelen, struct minix_dir_entry ** res_dir)
  70 {
  71         unsigned long block, offset;
  72         struct buffer_head * bh;
  73         struct minix_sb_info * info;
  74 
  75         *res_dir = NULL;
  76         if (!dir || !dir->i_sb)
  77                 return NULL;
  78         info = &dir->i_sb->u.minix_sb;
  79         if (namelen > info->s_namelen) {
  80 #ifdef NO_TRUNCATE
  81                 return NULL;
  82 #else
  83                 namelen = info->s_namelen;
  84 #endif
  85         }
  86         bh = NULL;
  87         block = offset = 0;
  88         while (block*BLOCK_SIZE+offset < dir->i_size) {
  89                 if (!bh) {
  90                         bh = minix_bread(dir,block,0);
  91                         if (!bh) {
  92                                 block++;
  93                                 continue;
  94                         }
  95                 }
  96                 *res_dir = (struct minix_dir_entry *) (bh->b_data + offset);
  97                 if (minix_match(namelen,name,bh,&offset,info))
  98                         return bh;
  99                 if (offset < bh->b_size)
 100                         continue;
 101                 brelse(bh);
 102                 bh = NULL;
 103                 offset = 0;
 104                 block++;
 105         }
 106         brelse(bh);
 107         *res_dir = NULL;
 108         return NULL;
 109 }
 110 
 111 int minix_lookup(struct inode * dir,const char * name, int len,
     /*  */
 112         struct inode ** result)
 113 {
 114         int ino;
 115         struct minix_dir_entry * de;
 116         struct buffer_head * bh;
 117 
 118         *result = NULL;
 119         if (!dir)
 120                 return -ENOENT;
 121         if (!S_ISDIR(dir->i_mode)) {
 122                 iput(dir);
 123                 return -ENOENT;
 124         }
 125         if (!(bh = minix_find_entry(dir,name,len,&de))) {
 126                 iput(dir);
 127                 return -ENOENT;
 128         }
 129         ino = de->inode;
 130         brelse(bh);
 131         if (!(*result = iget(dir->i_sb,ino))) {
 132                 iput(dir);
 133                 return -EACCES;
 134         }
 135         iput(dir);
 136         return 0;
 137 }
 138 
 139 /*
 140  *      minix_add_entry()
 141  *
 142  * adds a file entry to the specified directory, returning a possible
 143  * error value if it fails.
 144  *
 145  * NOTE!! The inode part of 'de' is left at 0 - which means you
 146  * may not sleep between calling this and putting something into
 147  * the entry, as someone else might have used it while you slept.
 148  */
 149 static int minix_add_entry(struct inode * dir,
     /*  */
 150         const char * name, int namelen,
 151         struct buffer_head ** res_buf,
 152         struct minix_dir_entry ** res_dir)
 153 {
 154         int i;
 155         unsigned long block, offset;
 156         struct buffer_head * bh;
 157         struct minix_dir_entry * de;
 158         struct minix_sb_info * info;
 159 
 160         *res_buf = NULL;
 161         *res_dir = NULL;
 162         if (!dir || !dir->i_sb)
 163                 return -ENOENT;
 164         info = &dir->i_sb->u.minix_sb;
 165         if (namelen > info->s_namelen) {
 166 #ifdef NO_TRUNCATE
 167                 return -ENAMETOOLONG;
 168 #else
 169                 namelen = info->s_namelen;
 170 #endif
 171         }
 172         if (!namelen)
 173                 return -ENOENT;
 174         bh = NULL;
 175         block = offset = 0;
 176         while (1) {
 177                 if (!bh) {
 178                         bh = minix_bread(dir,block,1);
 179                         if (!bh)
 180                                 return -ENOSPC;
 181                 }
 182                 de = (struct minix_dir_entry *) (bh->b_data + offset);
 183                 offset += info->s_dirsize;
 184                 if (block*bh->b_size + offset > dir->i_size) {
 185                         de->inode = 0;
 186                         dir->i_size = block*bh->b_size + offset;
 187                         dir->i_dirt = 1;
 188                 }
 189                 if (de->inode) {
 190                         if (namecompare(namelen, info->s_namelen, name, de->name)) {
 191                                 brelse(bh);
 192                                 return -EEXIST;
 193                         }
 194                 } else {
 195                         dir->i_mtime = dir->i_ctime = CURRENT_TIME;
 196                         dir->i_dirt = 1;
 197                         for (i = 0; i < info->s_namelen ; i++)
 198                                 de->name[i] = (i < namelen) ? name[i] : 0;
 199                         dir->i_version = ++event;
 200                         mark_buffer_dirty(bh, 1);
 201                         *res_dir = de;
 202                         break;
 203                 }
 204                 if (offset < bh->b_size)
 205                         continue;
 206                 brelse(bh);
 207                 bh = NULL;
 208                 offset = 0;
 209                 block++;
 210         }
 211         *res_buf = bh;
 212         return 0;
 213 }
 214 
 215 int minix_create(struct inode * dir,const char * name, int len, int mode,
     /*  */
 216         struct inode ** result)
 217 {
 218         int error;
 219         struct inode * inode;
 220         struct buffer_head * bh;
 221         struct minix_dir_entry * de;
 222 
 223         *result = NULL;
 224         if (!dir)
 225                 return -ENOENT;
 226         inode = minix_new_inode(dir);
 227         if (!inode) {
 228                 iput(dir);
 229                 return -ENOSPC;
 230         }
 231         inode->i_op = &minix_file_inode_operations;
 232         inode->i_mode = mode;
 233         inode->i_dirt = 1;
 234         error = minix_add_entry(dir,name,len, &bh ,&de);
 235         if (error) {
 236                 inode->i_nlink--;
 237                 inode->i_dirt = 1;
 238                 iput(inode);
 239                 iput(dir);
 240                 return error;
 241         }
 242         de->inode = inode->i_ino;
 243         mark_buffer_dirty(bh, 1);
 244         brelse(bh);
 245         iput(dir);
 246         *result = inode;
 247         return 0;
 248 }
 249 
 250 int minix_mknod(struct inode * dir, const char * name, int len, int mode, int rdev)
     /*  */
 251 {
 252         int error;
 253         struct inode * inode;
 254         struct buffer_head * bh;
 255         struct minix_dir_entry * de;
 256 
 257         if (!dir)
 258                 return -ENOENT;
 259         bh = minix_find_entry(dir,name,len,&de);
 260         if (bh) {
 261                 brelse(bh);
 262                 iput(dir);
 263                 return -EEXIST;
 264         }
 265         inode = minix_new_inode(dir);
 266         if (!inode) {
 267                 iput(dir);
 268                 return -ENOSPC;
 269         }
 270         inode->i_uid = current->fsuid;
 271         inode->i_mode = mode;
 272         inode->i_op = NULL;
 273         if (S_ISREG(inode->i_mode))
 274                 inode->i_op = &minix_file_inode_operations;
 275         else if (S_ISDIR(inode->i_mode)) {
 276                 inode->i_op = &minix_dir_inode_operations;
 277                 if (dir->i_mode & S_ISGID)
 278                         inode->i_mode |= S_ISGID;
 279         }
 280         else if (S_ISLNK(inode->i_mode))
 281                 inode->i_op = &minix_symlink_inode_operations;
 282         else if (S_ISCHR(inode->i_mode))
 283                 inode->i_op = &chrdev_inode_operations;
 284         else if (S_ISBLK(inode->i_mode))
 285                 inode->i_op = &blkdev_inode_operations;
 286         else if (S_ISFIFO(inode->i_mode))
 287                 init_fifo(inode);
 288         if (S_ISBLK(mode) || S_ISCHR(mode))
 289                 inode->i_rdev = rdev;
 290         inode->i_dirt = 1;
 291         error = minix_add_entry(dir, name, len, &bh, &de);
 292         if (error) {
 293                 inode->i_nlink--;
 294                 inode->i_dirt = 1;
 295                 iput(inode);
 296                 iput(dir);
 297                 return error;
 298         }
 299         de->inode = inode->i_ino;
 300         mark_buffer_dirty(bh, 1);
 301         brelse(bh);
 302         iput(dir);
 303         iput(inode);
 304         return 0;
 305 }
 306 
 307 int minix_mkdir(struct inode * dir, const char * name, int len, int mode)
     /*  */
 308 {
 309         int error;
 310         struct inode * inode;
 311         struct buffer_head * bh, *dir_block;
 312         struct minix_dir_entry * de;
 313         struct minix_sb_info * info;
 314 
 315         if (!dir || !dir->i_sb) {
 316                 iput(dir);
 317                 return -EINVAL;
 318         }
 319         info = &dir->i_sb->u.minix_sb;
 320         bh = minix_find_entry(dir,name,len,&de);
 321         if (bh) {
 322                 brelse(bh);
 323                 iput(dir);
 324                 return -EEXIST;
 325         }
 326         if (dir->i_nlink >= MINIX_LINK_MAX) {
 327                 iput(dir);
 328                 return -EMLINK;
 329         }
 330         inode = minix_new_inode(dir);
 331         if (!inode) {
 332                 iput(dir);
 333                 return -ENOSPC;
 334         }
 335         inode->i_op = &minix_dir_inode_operations;
 336         inode->i_size = 2 * info->s_dirsize;
 337         dir_block = minix_bread(inode,0,1);
 338         if (!dir_block) {
 339                 iput(dir);
 340                 inode->i_nlink--;
 341                 inode->i_dirt = 1;
 342                 iput(inode);
 343                 return -ENOSPC;
 344         }
 345         de = (struct minix_dir_entry *) dir_block->b_data;
 346         de->inode=inode->i_ino;
 347         strcpy(de->name,".");
 348         de = (struct minix_dir_entry *) (dir_block->b_data + info->s_dirsize);
 349         de->inode = dir->i_ino;
 350         strcpy(de->name,"..");
 351         inode->i_nlink = 2;
 352         mark_buffer_dirty(dir_block, 1);
 353         brelse(dir_block);
 354         inode->i_mode = S_IFDIR | (mode & 0777 & ~current->fs->umask);
 355         if (dir->i_mode & S_ISGID)
 356                 inode->i_mode |= S_ISGID;
 357         inode->i_dirt = 1;
 358         error = minix_add_entry(dir, name, len, &bh, &de);
 359         if (error) {
 360                 iput(dir);
 361                 inode->i_nlink=0;
 362                 iput(inode);
 363                 return error;
 364         }
 365         de->inode = inode->i_ino;
 366         mark_buffer_dirty(bh, 1);
 367         dir->i_nlink++;
 368         dir->i_dirt = 1;
 369         iput(dir);
 370         iput(inode);
 371         brelse(bh);
 372         return 0;
 373 }
 374 
 375 /*
 376  * routine to check that the specified directory is empty (for rmdir)
 377  */
 378 static int empty_dir(struct inode * inode)
     /*  */
 379 {
 380         unsigned int block, offset;
 381         struct buffer_head * bh;
 382         struct minix_dir_entry * de;
 383         struct minix_sb_info * info;
 384 
 385         if (!inode || !inode->i_sb)
 386                 return 1;
 387         info = &inode->i_sb->u.minix_sb;
 388         block = 0;
 389         bh = NULL;
 390         offset = 2*info->s_dirsize;
 391         if (inode->i_size & (info->s_dirsize-1))
 392                 goto bad_dir;
 393         if (inode->i_size < offset)
 394                 goto bad_dir;
 395         bh = minix_bread(inode,0,0);
 396         if (!bh)
 397                 goto bad_dir;
 398         de = (struct minix_dir_entry *) bh->b_data;
 399         if (!de->inode || strcmp(de->name,"."))
 400                 goto bad_dir;
 401         de = (struct minix_dir_entry *) (bh->b_data + info->s_dirsize);
 402         if (!de->inode || strcmp(de->name,".."))
 403                 goto bad_dir;
 404         while (block*BLOCK_SIZE+offset < inode->i_size) {
 405                 if (!bh) {
 406                         bh = minix_bread(inode,block,0);
 407                         if (!bh) {
 408                                 block++;
 409                                 continue;
 410                         }
 411                 }
 412                 de = (struct minix_dir_entry *) (bh->b_data + offset);
 413                 offset += info->s_dirsize;
 414                 if (de->inode) {
 415                         brelse(bh);
 416                         return 0;
 417                 }
 418                 if (offset < bh->b_size)
 419                         continue;
 420                 brelse(bh);
 421                 bh = NULL;
 422                 offset = 0;
 423                 block++;
 424         }
 425         brelse(bh);
 426         return 1;
 427 bad_dir:
 428         brelse(bh);
 429         printk("Bad directory on device %04x\n",inode->i_dev);
 430         return 1;
 431 }
 432 
 433 int minix_rmdir(struct inode * dir, const char * name, int len)
     /*  */
 434 {
 435         int retval;
 436         struct inode * inode;
 437         struct buffer_head * bh;
 438         struct minix_dir_entry * de;
 439 
 440         inode = NULL;
 441         bh = minix_find_entry(dir,name,len,&de);
 442         retval = -ENOENT;
 443         if (!bh)
 444                 goto end_rmdir;
 445         retval = -EPERM;
 446         if (!(inode = iget(dir->i_sb, de->inode)))
 447                 goto end_rmdir;
 448         if ((dir->i_mode & S_ISVTX) && !fsuser() &&
 449             current->fsuid != inode->i_uid &&
 450             current->fsuid != dir->i_uid)
 451                 goto end_rmdir;
 452         if (inode->i_dev != dir->i_dev)
 453                 goto end_rmdir;
 454         if (inode == dir)       /* we may not delete ".", but "../dir" is ok */
 455                 goto end_rmdir;
 456         if (!S_ISDIR(inode->i_mode)) {
 457                 retval = -ENOTDIR;
 458                 goto end_rmdir;
 459         }
 460         if (!empty_dir(inode)) {
 461                 retval = -ENOTEMPTY;
 462                 goto end_rmdir;
 463         }
 464         if (de->inode != inode->i_ino) {
 465                 retval = -ENOENT;
 466                 goto end_rmdir;
 467         }
 468         if (inode->i_count > 1) {
 469                 retval = -EBUSY;
 470                 goto end_rmdir;
 471         }
 472         if (inode->i_nlink != 2)
 473                 printk("empty directory has nlink!=2 (%d)\n",inode->i_nlink);
 474         de->inode = 0;
 475         dir->i_version = ++event;
 476         mark_buffer_dirty(bh, 1);
 477         inode->i_nlink=0;
 478         inode->i_dirt=1;
 479         inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 480         dir->i_nlink--;
 481         dir->i_dirt=1;
 482         retval = 0;
 483 end_rmdir:
 484         iput(dir);
 485         iput(inode);
 486         brelse(bh);
 487         return retval;
 488 }
 489 
 490 int minix_unlink(struct inode * dir, const char * name, int len)
     /*  */
 491 {
 492         int retval;
 493         struct inode * inode;
 494         struct buffer_head * bh;
 495         struct minix_dir_entry * de;
 496 
 497 repeat:
 498         retval = -ENOENT;
 499         inode = NULL;
 500         bh = minix_find_entry(dir,name,len,&de);
 501         if (!bh)
 502                 goto end_unlink;
 503         if (!(inode = iget(dir->i_sb, de->inode)))
 504                 goto end_unlink;
 505         retval = -EPERM;
 506         if (S_ISDIR(inode->i_mode))
 507                 goto end_unlink;
 508         if (de->inode != inode->i_ino) {
 509                 iput(inode);
 510                 brelse(bh);
 511                 current->counter = 0;
 512                 schedule();
 513                 goto repeat;
 514         }
 515         if ((dir->i_mode & S_ISVTX) && !fsuser() &&
 516             current->fsuid != inode->i_uid &&
 517             current->fsuid != dir->i_uid)
 518                 goto end_unlink;
 519         if (de->inode != inode->i_ino) {
 520                 retval = -ENOENT;
 521                 goto end_unlink;
 522         }
 523         if (!inode->i_nlink) {
 524                 printk("Deleting nonexistent file (%04x:%lu), %d\n",
 525                         inode->i_dev,inode->i_ino,inode->i_nlink);
 526                 inode->i_nlink=1;
 527         }
 528         de->inode = 0;
 529         dir->i_version = ++event;
 530         mark_buffer_dirty(bh, 1);
 531         dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 532         dir->i_dirt = 1;
 533         inode->i_nlink--;
 534         inode->i_ctime = dir->i_ctime;
 535         inode->i_dirt = 1;
 536         retval = 0;
 537 end_unlink:
 538         brelse(bh);
 539         iput(inode);
 540         iput(dir);
 541         return retval;
 542 }
 543 
 544 int minix_symlink(struct inode * dir, const char * name, int len, const char * symname)
     /*  */
 545 {
 546         struct minix_dir_entry * de;
 547         struct inode * inode = NULL;
 548         struct buffer_head * bh = NULL, * name_block = NULL;
 549         int i;
 550         char c;
 551 
 552         if (!(inode = minix_new_inode(dir))) {
 553                 iput(dir);
 554                 return -ENOSPC;
 555         }
 556         inode->i_mode = S_IFLNK | 0777;
 557         inode->i_op = &minix_symlink_inode_operations;
 558         name_block = minix_bread(inode,0,1);
 559         if (!name_block) {
 560                 iput(dir);
 561                 inode->i_nlink--;
 562                 inode->i_dirt = 1;
 563                 iput(inode);
 564                 return -ENOSPC;
 565         }
 566         i = 0;
 567         while (i < 1023 && (c=*(symname++)))
 568                 name_block->b_data[i++] = c;
 569         name_block->b_data[i] = 0;
 570         mark_buffer_dirty(name_block, 1);
 571         brelse(name_block);
 572         inode->i_size = i;
 573         inode->i_dirt = 1;
 574         bh = minix_find_entry(dir,name,len,&de);
 575         if (bh) {
 576                 inode->i_nlink--;
 577                 inode->i_dirt = 1;
 578                 iput(inode);
 579                 brelse(bh);
 580                 iput(dir);
 581                 return -EEXIST;
 582         }
 583         i = minix_add_entry(dir, name, len, &bh, &de);
 584         if (i) {
 585                 inode->i_nlink--;
 586                 inode->i_dirt = 1;
 587                 iput(inode);
 588                 iput(dir);
 589                 return i;
 590         }
 591         de->inode = inode->i_ino;
 592         mark_buffer_dirty(bh, 1);
 593         brelse(bh);
 594         iput(dir);
 595         iput(inode);
 596         return 0;
 597 }
 598 
 599 int minix_link(struct inode * oldinode, struct inode * dir, const char * name, int len)
     /*  */
 600 {
 601         int error;
 602         struct minix_dir_entry * de;
 603         struct buffer_head * bh;
 604 
 605         if (S_ISDIR(oldinode->i_mode)) {
 606                 iput(oldinode);
 607                 iput(dir);
 608                 return -EPERM;
 609         }
 610         if (oldinode->i_nlink >= MINIX_LINK_MAX) {
 611                 iput(oldinode);
 612                 iput(dir);
 613                 return -EMLINK;
 614         }
 615         bh = minix_find_entry(dir,name,len,&de);
 616         if (bh) {
 617                 brelse(bh);
 618                 iput(dir);
 619                 iput(oldinode);
 620                 return -EEXIST;
 621         }
 622         error = minix_add_entry(dir, name, len, &bh, &de);
 623         if (error) {
 624                 iput(dir);
 625                 iput(oldinode);
 626                 return error;
 627         }
 628         de->inode = oldinode->i_ino;
 629         mark_buffer_dirty(bh, 1);
 630         brelse(bh);
 631         iput(dir);
 632         oldinode->i_nlink++;
 633         oldinode->i_ctime = CURRENT_TIME;
 634         oldinode->i_dirt = 1;
 635         iput(oldinode);
 636         return 0;
 637 }
 638 
 639 static int subdir(struct inode * new_inode, struct inode * old_inode)
     /*  */
 640 {
 641         int ino;
 642         int result;
 643 
 644         new_inode->i_count++;
 645         result = 0;
 646         for (;;) {
 647                 if (new_inode == old_inode) {
 648                         result = 1;
 649                         break;
 650                 }
 651                 if (new_inode->i_dev != old_inode->i_dev)
 652                         break;
 653                 ino = new_inode->i_ino;
 654                 if (minix_lookup(new_inode,"..",2,&new_inode))
 655                         break;
 656                 if (new_inode->i_ino == ino)
 657                         break;
 658         }
 659         iput(new_inode);
 660         return result;
 661 }
 662 
 663 #define PARENT_INO(buffer) \
 664 (((struct minix_dir_entry *) ((buffer)+info->s_dirsize))->inode)
 665 
 666 /*
 667  * rename uses retrying to avoid race-conditions: at least they should be minimal.
 668  * it tries to allocate all the blocks, then sanity-checks, and if the sanity-
 669  * checks fail, it tries to restart itself again. Very practical - no changes
 670  * are done until we know everything works ok.. and then all the changes can be
 671  * done in one fell swoop when we have claimed all the buffers needed.
 672  *
 673  * Anybody can rename anything with this: the permission checks are left to the
 674  * higher-level routines.
 675  */
 676 static int do_minix_rename(struct inode * old_dir, const char * old_name, int old_len,
     /*  */
 677         struct inode * new_dir, const char * new_name, int new_len)
 678 {
 679         struct inode * old_inode, * new_inode;
 680         struct buffer_head * old_bh, * new_bh, * dir_bh;
 681         struct minix_dir_entry * old_de, * new_de;
 682         struct minix_sb_info * info;
 683         int retval;
 684 
 685         info = &old_dir->i_sb->u.minix_sb;
 686         goto start_up;
 687 try_again:
 688         brelse(old_bh);
 689         brelse(new_bh);
 690         brelse(dir_bh);
 691         iput(old_inode);
 692         iput(new_inode);
 693         current->counter = 0;
 694         schedule();
 695 start_up:
 696         old_inode = new_inode = NULL;
 697         old_bh = new_bh = dir_bh = NULL;
 698         old_bh = minix_find_entry(old_dir,old_name,old_len,&old_de);
 699         retval = -ENOENT;
 700         if (!old_bh)
 701                 goto end_rename;
 702         old_inode = __iget(old_dir->i_sb, old_de->inode,0); /* don't cross mnt-points */
 703         if (!old_inode)
 704                 goto end_rename;
 705         retval = -EPERM;
 706         if ((old_dir->i_mode & S_ISVTX) && 
 707             current->fsuid != old_inode->i_uid &&
 708             current->fsuid != old_dir->i_uid && !fsuser())
 709                 goto end_rename;
 710         new_bh = minix_find_entry(new_dir,new_name,new_len,&new_de);
 711         if (new_bh) {
 712                 new_inode = __iget(new_dir->i_sb, new_de->inode, 0);
 713                 if (!new_inode) {
 714                         brelse(new_bh);
 715                         new_bh = NULL;
 716                 }
 717         }
 718         if (new_inode == old_inode) {
 719                 retval = 0;
 720                 goto end_rename;
 721         }
 722         if (new_inode && S_ISDIR(new_inode->i_mode)) {
 723                 retval = -EISDIR;
 724                 if (!S_ISDIR(old_inode->i_mode))
 725                         goto end_rename;
 726                 retval = -EINVAL;
 727                 if (subdir(new_dir, old_inode))
 728                         goto end_rename;
 729                 retval = -ENOTEMPTY;
 730                 if (!empty_dir(new_inode))
 731                         goto end_rename;
 732                 retval = -EBUSY;
 733                 if (new_inode->i_count > 1)
 734                         goto end_rename;
 735         }
 736         retval = -EPERM;
 737         if (new_inode && (new_dir->i_mode & S_ISVTX) && 
 738             current->fsuid != new_inode->i_uid &&
 739             current->fsuid != new_dir->i_uid && !fsuser())
 740                 goto end_rename;
 741         if (S_ISDIR(old_inode->i_mode)) {
 742                 retval = -ENOTDIR;
 743                 if (new_inode && !S_ISDIR(new_inode->i_mode))
 744                         goto end_rename;
 745                 retval = -EINVAL;
 746                 if (subdir(new_dir, old_inode))
 747                         goto end_rename;
 748                 retval = -EIO;
 749                 dir_bh = minix_bread(old_inode,0,0);
 750                 if (!dir_bh)
 751                         goto end_rename;
 752                 if (PARENT_INO(dir_bh->b_data) != old_dir->i_ino)
 753                         goto end_rename;
 754                 retval = -EMLINK;
 755                 if (!new_inode && new_dir->i_nlink >= MINIX_LINK_MAX)
 756                         goto end_rename;
 757         }
 758         if (!new_bh) {
 759                 retval = minix_add_entry(new_dir,new_name,new_len,&new_bh,&new_de);
 760                 if (retval)
 761                         goto end_rename;
 762         }
 763 /* sanity checking before doing the rename - avoid races */
 764         if (new_inode && (new_de->inode != new_inode->i_ino))
 765                 goto try_again;
 766         if (new_de->inode && !new_inode)
 767                 goto try_again;
 768         if (old_de->inode != old_inode->i_ino)
 769                 goto try_again;
 770 /* ok, that's it */
 771         old_de->inode = 0;
 772         new_de->inode = old_inode->i_ino;
 773         old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME;
 774         old_dir->i_dirt = 1;
 775         old_dir->i_version = ++event;
 776         new_dir->i_ctime = new_dir->i_mtime = CURRENT_TIME;
 777         new_dir->i_dirt = 1;
 778         new_dir->i_version = ++event;
 779         if (new_inode) {
 780                 new_inode->i_nlink--;
 781                 new_inode->i_ctime = CURRENT_TIME;
 782                 new_inode->i_dirt = 1;
 783         }
 784         mark_buffer_dirty(old_bh, 1);
 785         mark_buffer_dirty(new_bh, 1);
 786         if (dir_bh) {
 787                 PARENT_INO(dir_bh->b_data) = new_dir->i_ino;
 788                 mark_buffer_dirty(dir_bh, 1);
 789                 old_dir->i_nlink--;
 790                 old_dir->i_dirt = 1;
 791                 if (new_inode) {
 792                         new_inode->i_nlink--;
 793                         new_inode->i_dirt = 1;
 794                 } else {
 795                         new_dir->i_nlink++;
 796                         new_dir->i_dirt = 1;
 797                 }
 798         }
 799         retval = 0;
 800 end_rename:
 801         brelse(dir_bh);
 802         brelse(old_bh);
 803         brelse(new_bh);
 804         iput(old_inode);
 805         iput(new_inode);
 806         iput(old_dir);
 807         iput(new_dir);
 808         return retval;
 809 }
 810 
 811 /*
 812  * Ok, rename also locks out other renames, as they can change the parent of
 813  * a directory, and we don't want any races. Other races are checked for by
 814  * "do_rename()", which restarts if there are inconsistencies.
 815  *
 816  * Note that there is no race between different filesystems: it's only within
 817  * the same device that races occur: many renames can happen at once, as long
 818  * as they are on different partitions.
 819  */
 820 int minix_rename(struct inode * old_dir, const char * old_name, int old_len,
     /*  */
 821         struct inode * new_dir, const char * new_name, int new_len)
 822 {
 823         static struct wait_queue * wait = NULL;
 824         static int lock = 0;
 825         int result;
 826 
 827         while (lock)
 828                 sleep_on(&wait);
 829         lock = 1;
 830         result = do_minix_rename(old_dir, old_name, old_len,
 831                 new_dir, new_name, new_len);
 832         lock = 0;
 833         wake_up(&wait);
 834         return result;
 835 }

/* */