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

/* */