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 || !buffer[len]) {
  27                 unsigned char same;
  28                 __asm__("repe ; cmpsb ; setz %0"
  29                         :"=q" (same)
  30                         :"S" ((long) name),"D" ((long) buffer),"c" (len)
  31                         :"cx","di","si");
  32                 return same;
  33         }
  34         return 0;
  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                         for (i = 0; i < info->s_namelen ; i++)
 197                                 de->name[i] = (i < namelen) ? name[i] : 0;
 198                         mark_buffer_dirty(bh, 1);
 199                         *res_dir = de;
 200                         break;
 201                 }
 202                 if (offset < bh->b_size)
 203                         continue;
 204                 brelse(bh);
 205                 bh = NULL;
 206                 offset = 0;
 207                 block++;
 208         }
 209         *res_buf = bh;
 210         return 0;
 211 }
 212 
 213 int minix_create(struct inode * dir,const char * name, int len, int mode,
     /*  */
 214         struct inode ** result)
 215 {
 216         int error;
 217         struct inode * inode;
 218         struct buffer_head * bh;
 219         struct minix_dir_entry * de;
 220 
 221         *result = NULL;
 222         if (!dir)
 223                 return -ENOENT;
 224         inode = minix_new_inode(dir);
 225         if (!inode) {
 226                 iput(dir);
 227                 return -ENOSPC;
 228         }
 229         inode->i_op = &minix_file_inode_operations;
 230         inode->i_mode = mode;
 231         inode->i_dirt = 1;
 232         error = minix_add_entry(dir,name,len, &bh ,&de);
 233         if (error) {
 234                 inode->i_nlink--;
 235                 inode->i_dirt = 1;
 236                 iput(inode);
 237                 iput(dir);
 238                 return error;
 239         }
 240         de->inode = inode->i_ino;
 241         mark_buffer_dirty(bh, 1);
 242         brelse(bh);
 243         iput(dir);
 244         *result = inode;
 245         return 0;
 246 }
 247 
 248 int minix_mknod(struct inode * dir, const char * name, int len, int mode, int rdev)
     /*  */
 249 {
 250         int error;
 251         struct inode * inode;
 252         struct buffer_head * bh;
 253         struct minix_dir_entry * de;
 254 
 255         if (!dir)
 256                 return -ENOENT;
 257         bh = minix_find_entry(dir,name,len,&de);
 258         if (bh) {
 259                 brelse(bh);
 260                 iput(dir);
 261                 return -EEXIST;
 262         }
 263         inode = minix_new_inode(dir);
 264         if (!inode) {
 265                 iput(dir);
 266                 return -ENOSPC;
 267         }
 268         inode->i_uid = current->euid;
 269         inode->i_mode = mode;
 270         inode->i_op = NULL;
 271         if (S_ISREG(inode->i_mode))
 272                 inode->i_op = &minix_file_inode_operations;
 273         else if (S_ISDIR(inode->i_mode)) {
 274                 inode->i_op = &minix_dir_inode_operations;
 275                 if (dir->i_mode & S_ISGID)
 276                         inode->i_mode |= S_ISGID;
 277         }
 278         else if (S_ISLNK(inode->i_mode))
 279                 inode->i_op = &minix_symlink_inode_operations;
 280         else if (S_ISCHR(inode->i_mode))
 281                 inode->i_op = &chrdev_inode_operations;
 282         else if (S_ISBLK(inode->i_mode))
 283                 inode->i_op = &blkdev_inode_operations;
 284         else if (S_ISFIFO(inode->i_mode))
 285                 init_fifo(inode);
 286         if (S_ISBLK(mode) || S_ISCHR(mode))
 287                 inode->i_rdev = rdev;
 288         inode->i_dirt = 1;
 289         error = minix_add_entry(dir, name, len, &bh, &de);
 290         if (error) {
 291                 inode->i_nlink--;
 292                 inode->i_dirt = 1;
 293                 iput(inode);
 294                 iput(dir);
 295                 return error;
 296         }
 297         de->inode = inode->i_ino;
 298         mark_buffer_dirty(bh, 1);
 299         brelse(bh);
 300         iput(dir);
 301         iput(inode);
 302         return 0;
 303 }
 304 
 305 int minix_mkdir(struct inode * dir, const char * name, int len, int mode)
     /*  */
 306 {
 307         int error;
 308         struct inode * inode;
 309         struct buffer_head * bh, *dir_block;
 310         struct minix_dir_entry * de;
 311         struct minix_sb_info * info;
 312 
 313         if (!dir || !dir->i_sb) {
 314                 iput(dir);
 315                 return -EINVAL;
 316         }
 317         info = &dir->i_sb->u.minix_sb;
 318         bh = minix_find_entry(dir,name,len,&de);
 319         if (bh) {
 320                 brelse(bh);
 321                 iput(dir);
 322                 return -EEXIST;
 323         }
 324         if (dir->i_nlink >= MINIX_LINK_MAX) {
 325                 iput(dir);
 326                 return -EMLINK;
 327         }
 328         inode = minix_new_inode(dir);
 329         if (!inode) {
 330                 iput(dir);
 331                 return -ENOSPC;
 332         }
 333         inode->i_op = &minix_dir_inode_operations;
 334         inode->i_size = 2 * info->s_dirsize;
 335         dir_block = minix_bread(inode,0,1);
 336         if (!dir_block) {
 337                 iput(dir);
 338                 inode->i_nlink--;
 339                 inode->i_dirt = 1;
 340                 iput(inode);
 341                 return -ENOSPC;
 342         }
 343         de = (struct minix_dir_entry *) dir_block->b_data;
 344         de->inode=inode->i_ino;
 345         strcpy(de->name,".");
 346         de = (struct minix_dir_entry *) (dir_block->b_data + info->s_dirsize);
 347         de->inode = dir->i_ino;
 348         strcpy(de->name,"..");
 349         inode->i_nlink = 2;
 350         mark_buffer_dirty(dir_block, 1);
 351         brelse(dir_block);
 352         inode->i_mode = S_IFDIR | (mode & 0777 & ~current->umask);
 353         if (dir->i_mode & S_ISGID)
 354                 inode->i_mode |= S_ISGID;
 355         inode->i_dirt = 1;
 356         error = minix_add_entry(dir, name, len, &bh, &de);
 357         if (error) {
 358                 iput(dir);
 359                 inode->i_nlink=0;
 360                 iput(inode);
 361                 return error;
 362         }
 363         de->inode = inode->i_ino;
 364         mark_buffer_dirty(bh, 1);
 365         dir->i_nlink++;
 366         dir->i_dirt = 1;
 367         iput(dir);
 368         iput(inode);
 369         brelse(bh);
 370         return 0;
 371 }
 372 
 373 /*
 374  * routine to check that the specified directory is empty (for rmdir)
 375  */
 376 static int empty_dir(struct inode * inode)
     /*  */
 377 {
 378         unsigned int block, offset;
 379         struct buffer_head * bh;
 380         struct minix_dir_entry * de;
 381         struct minix_sb_info * info;
 382 
 383         if (!inode || !inode->i_sb)
 384                 return 1;
 385         info = &inode->i_sb->u.minix_sb;
 386         block = 0;
 387         bh = NULL;
 388         offset = 2*info->s_dirsize;
 389         if (inode->i_size & (info->s_dirsize-1))
 390                 goto bad_dir;
 391         if (inode->i_size < offset)
 392                 goto bad_dir;
 393         bh = minix_bread(inode,0,0);
 394         if (!bh)
 395                 goto bad_dir;
 396         de = (struct minix_dir_entry *) bh->b_data;
 397         if (!de->inode || strcmp(de->name,"."))
 398                 goto bad_dir;
 399         de = (struct minix_dir_entry *) (bh->b_data + info->s_dirsize);
 400         if (!de->inode || strcmp(de->name,".."))
 401                 goto bad_dir;
 402         while (block*BLOCK_SIZE+offset < inode->i_size) {
 403                 if (!bh) {
 404                         bh = minix_bread(inode,block,0);
 405                         if (!bh) {
 406                                 block++;
 407                                 continue;
 408                         }
 409                 }
 410                 de = (struct minix_dir_entry *) (bh->b_data + offset);
 411                 offset += info->s_dirsize;
 412                 if (de->inode) {
 413                         brelse(bh);
 414                         return 0;
 415                 }
 416                 if (offset < bh->b_size)
 417                         continue;
 418                 brelse(bh);
 419                 bh = NULL;
 420                 offset = 0;
 421                 block++;
 422         }
 423         brelse(bh);
 424         return 1;
 425 bad_dir:
 426         brelse(bh);
 427         printk("Bad directory on device %04x\n",inode->i_dev);
 428         return 1;
 429 }
 430 
 431 int minix_rmdir(struct inode * dir, const char * name, int len)
     /*  */
 432 {
 433         int retval;
 434         struct inode * inode;
 435         struct buffer_head * bh;
 436         struct minix_dir_entry * de;
 437 
 438         inode = NULL;
 439         bh = minix_find_entry(dir,name,len,&de);
 440         retval = -ENOENT;
 441         if (!bh)
 442                 goto end_rmdir;
 443         retval = -EPERM;
 444         if (!(inode = iget(dir->i_sb, de->inode)))
 445                 goto end_rmdir;
 446         if ((dir->i_mode & S_ISVTX) && current->euid &&
 447            inode->i_uid != current->euid)
 448                 goto end_rmdir;
 449         if (inode->i_dev != dir->i_dev)
 450                 goto end_rmdir;
 451         if (inode == dir)       /* we may not delete ".", but "../dir" is ok */
 452                 goto end_rmdir;
 453         if (!S_ISDIR(inode->i_mode)) {
 454                 retval = -ENOTDIR;
 455                 goto end_rmdir;
 456         }
 457         if (!empty_dir(inode)) {
 458                 retval = -ENOTEMPTY;
 459                 goto end_rmdir;
 460         }
 461         if (de->inode != inode->i_ino) {
 462                 retval = -ENOENT;
 463                 goto end_rmdir;
 464         }
 465         if (inode->i_count > 1) {
 466                 retval = -EBUSY;
 467                 goto end_rmdir;
 468         }
 469         if (inode->i_nlink != 2)
 470                 printk("empty directory has nlink!=2 (%d)\n",inode->i_nlink);
 471         de->inode = 0;
 472         mark_buffer_dirty(bh, 1);
 473         inode->i_nlink=0;
 474         inode->i_dirt=1;
 475         dir->i_nlink--;
 476         inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 477         dir->i_dirt=1;
 478         retval = 0;
 479 end_rmdir:
 480         iput(dir);
 481         iput(inode);
 482         brelse(bh);
 483         return retval;
 484 }
 485 
 486 int minix_unlink(struct inode * dir, const char * name, int len)
     /*  */
 487 {
 488         int retval;
 489         struct inode * inode;
 490         struct buffer_head * bh;
 491         struct minix_dir_entry * de;
 492 
 493 repeat:
 494         retval = -ENOENT;
 495         inode = NULL;
 496         bh = minix_find_entry(dir,name,len,&de);
 497         if (!bh)
 498                 goto end_unlink;
 499         if (!(inode = iget(dir->i_sb, de->inode)))
 500                 goto end_unlink;
 501         retval = -EPERM;
 502         if (S_ISDIR(inode->i_mode))
 503                 goto end_unlink;
 504         if (de->inode != inode->i_ino) {
 505                 iput(inode);
 506                 brelse(bh);
 507                 current->counter = 0;
 508                 schedule();
 509                 goto repeat;
 510         }
 511         if ((dir->i_mode & S_ISVTX) && !suser() &&
 512             current->euid != inode->i_uid &&
 513             current->euid != dir->i_uid)
 514                 goto end_unlink;
 515         if (de->inode != inode->i_ino) {
 516                 retval = -ENOENT;
 517                 goto end_unlink;
 518         }
 519         if (!inode->i_nlink) {
 520                 printk("Deleting nonexistent file (%04x:%lu), %d\n",
 521                         inode->i_dev,inode->i_ino,inode->i_nlink);
 522                 inode->i_nlink=1;
 523         }
 524         de->inode = 0;
 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->euid != old_inode->i_uid &&
 703             current->euid != old_dir->i_uid && !suser())
 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->euid != new_inode->i_uid &&
 734             current->euid != new_dir->i_uid && !suser())
 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         new_dir->i_ctime = new_dir->i_mtime = CURRENT_TIME;
 771         new_dir->i_dirt = 1;
 772         if (new_inode) {
 773                 new_inode->i_nlink--;
 774                 new_inode->i_ctime = CURRENT_TIME;
 775                 new_inode->i_dirt = 1;
 776         }
 777         mark_buffer_dirty(old_bh, 1);
 778         mark_buffer_dirty(new_bh, 1);
 779         if (dir_bh) {
 780                 PARENT_INO(dir_bh->b_data) = new_dir->i_ino;
 781                 mark_buffer_dirty(dir_bh, 1);
 782                 old_dir->i_nlink--;
 783                 old_dir->i_dirt = 1;
 784                 if (new_inode) {
 785                         new_inode->i_nlink--;
 786                         new_inode->i_dirt = 1;
 787                 } else {
 788                         new_dir->i_nlink++;
 789                         new_dir->i_dirt = 1;
 790                 }
 791         }
 792         retval = 0;
 793 end_rename:
 794         brelse(dir_bh);
 795         brelse(old_bh);
 796         brelse(new_bh);
 797         iput(old_inode);
 798         iput(new_inode);
 799         iput(old_dir);
 800         iput(new_dir);
 801         return retval;
 802 }
 803 
 804 /*
 805  * Ok, rename also locks out other renames, as they can change the parent of
 806  * a directory, and we don't want any races. Other races are checked for by
 807  * "do_rename()", which restarts if there are inconsistencies.
 808  *
 809  * Note that there is no race between different filesystems: it's only within
 810  * the same device that races occur: many renames can happen at once, as long
 811  * as they are on different partitions.
 812  */
 813 int minix_rename(struct inode * old_dir, const char * old_name, int old_len,
     /*  */
 814         struct inode * new_dir, const char * new_name, int new_len)
 815 {
 816         static struct wait_queue * wait = NULL;
 817         static int lock = 0;
 818         int result;
 819 
 820         while (lock)
 821                 sleep_on(&wait);
 822         lock = 1;
 823         result = do_minix_rename(old_dir, old_name, old_len,
 824                 new_dir, new_name, new_len);
 825         lock = 0;
 826         wake_up(&wait);
 827         return result;
 828 }

/* */