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                         dir->i_version = ++event;
 199                         mark_buffer_dirty(bh, 1);
 200                         *res_dir = de;
 201                         break;
 202                 }
 203                 if (offset < bh->b_size)
 204                         continue;
 205                 brelse(bh);
 206                 bh = NULL;
 207                 offset = 0;
 208                 block++;
 209         }
 210         *res_buf = bh;
 211         return 0;
 212 }
 213 
 214 int minix_create(struct inode * dir,const char * name, int len, int mode,
     /*  */
 215         struct inode ** result)
 216 {
 217         int error;
 218         struct inode * inode;
 219         struct buffer_head * bh;
 220         struct minix_dir_entry * de;
 221 
 222         *result = NULL;
 223         if (!dir)
 224                 return -ENOENT;
 225         inode = minix_new_inode(dir);
 226         if (!inode) {
 227                 iput(dir);
 228                 return -ENOSPC;
 229         }
 230         inode->i_op = &minix_file_inode_operations;
 231         inode->i_mode = mode;
 232         inode->i_dirt = 1;
 233         error = minix_add_entry(dir,name,len, &bh ,&de);
 234         if (error) {
 235                 inode->i_nlink--;
 236                 inode->i_dirt = 1;
 237                 iput(inode);
 238                 iput(dir);
 239                 return error;
 240         }
 241         de->inode = inode->i_ino;
 242         mark_buffer_dirty(bh, 1);
 243         brelse(bh);
 244         iput(dir);
 245         *result = inode;
 246         return 0;
 247 }
 248 
 249 int minix_mknod(struct inode * dir, const char * name, int len, int mode, int rdev)
     /*  */
 250 {
 251         int error;
 252         struct inode * inode;
 253         struct buffer_head * bh;
 254         struct minix_dir_entry * de;
 255 
 256         if (!dir)
 257                 return -ENOENT;
 258         bh = minix_find_entry(dir,name,len,&de);
 259         if (bh) {
 260                 brelse(bh);
 261                 iput(dir);
 262                 return -EEXIST;
 263         }
 264         inode = minix_new_inode(dir);
 265         if (!inode) {
 266                 iput(dir);
 267                 return -ENOSPC;
 268         }
 269         inode->i_uid = current->fsuid;
 270         inode->i_mode = mode;
 271         inode->i_op = NULL;
 272         if (S_ISREG(inode->i_mode))
 273                 inode->i_op = &minix_file_inode_operations;
 274         else if (S_ISDIR(inode->i_mode)) {
 275                 inode->i_op = &minix_dir_inode_operations;
 276                 if (dir->i_mode & S_ISGID)
 277                         inode->i_mode |= S_ISGID;
 278         }
 279         else if (S_ISLNK(inode->i_mode))
 280                 inode->i_op = &minix_symlink_inode_operations;
 281         else if (S_ISCHR(inode->i_mode))
 282                 inode->i_op = &chrdev_inode_operations;
 283         else if (S_ISBLK(inode->i_mode))
 284                 inode->i_op = &blkdev_inode_operations;
 285         else if (S_ISFIFO(inode->i_mode))
 286                 init_fifo(inode);
 287         if (S_ISBLK(mode) || S_ISCHR(mode))
 288                 inode->i_rdev = rdev;
 289         inode->i_dirt = 1;
 290         error = minix_add_entry(dir, name, len, &bh, &de);
 291         if (error) {
 292                 inode->i_nlink--;
 293                 inode->i_dirt = 1;
 294                 iput(inode);
 295                 iput(dir);
 296                 return error;
 297         }
 298         de->inode = inode->i_ino;
 299         mark_buffer_dirty(bh, 1);
 300         brelse(bh);
 301         iput(dir);
 302         iput(inode);
 303         return 0;
 304 }
 305 
 306 int minix_mkdir(struct inode * dir, const char * name, int len, int mode)
     /*  */
 307 {
 308         int error;
 309         struct inode * inode;
 310         struct buffer_head * bh, *dir_block;
 311         struct minix_dir_entry * de;
 312         struct minix_sb_info * info;
 313 
 314         if (!dir || !dir->i_sb) {
 315                 iput(dir);
 316                 return -EINVAL;
 317         }
 318         info = &dir->i_sb->u.minix_sb;
 319         bh = minix_find_entry(dir,name,len,&de);
 320         if (bh) {
 321                 brelse(bh);
 322                 iput(dir);
 323                 return -EEXIST;
 324         }
 325         if (dir->i_nlink >= MINIX_LINK_MAX) {
 326                 iput(dir);
 327                 return -EMLINK;
 328         }
 329         inode = minix_new_inode(dir);
 330         if (!inode) {
 331                 iput(dir);
 332                 return -ENOSPC;
 333         }
 334         inode->i_op = &minix_dir_inode_operations;
 335         inode->i_size = 2 * info->s_dirsize;
 336         dir_block = minix_bread(inode,0,1);
 337         if (!dir_block) {
 338                 iput(dir);
 339                 inode->i_nlink--;
 340                 inode->i_dirt = 1;
 341                 iput(inode);
 342                 return -ENOSPC;
 343         }
 344         de = (struct minix_dir_entry *) dir_block->b_data;
 345         de->inode=inode->i_ino;
 346         strcpy(de->name,".");
 347         de = (struct minix_dir_entry *) (dir_block->b_data + info->s_dirsize);
 348         de->inode = dir->i_ino;
 349         strcpy(de->name,"..");
 350         inode->i_nlink = 2;
 351         mark_buffer_dirty(dir_block, 1);
 352         brelse(dir_block);
 353         inode->i_mode = S_IFDIR | (mode & 0777 & ~current->fs->umask);
 354         if (dir->i_mode & S_ISGID)
 355                 inode->i_mode |= S_ISGID;
 356         inode->i_dirt = 1;
 357         error = minix_add_entry(dir, name, len, &bh, &de);
 358         if (error) {
 359                 iput(dir);
 360                 inode->i_nlink=0;
 361                 iput(inode);
 362                 return error;
 363         }
 364         de->inode = inode->i_ino;
 365         mark_buffer_dirty(bh, 1);
 366         dir->i_nlink++;
 367         dir->i_dirt = 1;
 368         iput(dir);
 369         iput(inode);
 370         brelse(bh);
 371         return 0;
 372 }
 373 
 374 /*
 375  * routine to check that the specified directory is empty (for rmdir)
 376  */
 377 static int empty_dir(struct inode * inode)
     /*  */
 378 {
 379         unsigned int block, offset;
 380         struct buffer_head * bh;
 381         struct minix_dir_entry * de;
 382         struct minix_sb_info * info;
 383 
 384         if (!inode || !inode->i_sb)
 385                 return 1;
 386         info = &inode->i_sb->u.minix_sb;
 387         block = 0;
 388         bh = NULL;
 389         offset = 2*info->s_dirsize;
 390         if (inode->i_size & (info->s_dirsize-1))
 391                 goto bad_dir;
 392         if (inode->i_size < offset)
 393                 goto bad_dir;
 394         bh = minix_bread(inode,0,0);
 395         if (!bh)
 396                 goto bad_dir;
 397         de = (struct minix_dir_entry *) bh->b_data;
 398         if (!de->inode || strcmp(de->name,"."))
 399                 goto bad_dir;
 400         de = (struct minix_dir_entry *) (bh->b_data + info->s_dirsize);
 401         if (!de->inode || strcmp(de->name,".."))
 402                 goto bad_dir;
 403         while (block*BLOCK_SIZE+offset < inode->i_size) {
 404                 if (!bh) {
 405                         bh = minix_bread(inode,block,0);
 406                         if (!bh) {
 407                                 block++;
 408                                 continue;
 409                         }
 410                 }
 411                 de = (struct minix_dir_entry *) (bh->b_data + offset);
 412                 offset += info->s_dirsize;
 413                 if (de->inode) {
 414                         brelse(bh);
 415                         return 0;
 416                 }
 417                 if (offset < bh->b_size)
 418                         continue;
 419                 brelse(bh);
 420                 bh = NULL;
 421                 offset = 0;
 422                 block++;
 423         }
 424         brelse(bh);
 425         return 1;
 426 bad_dir:
 427         brelse(bh);
 428         printk("Bad directory on device %04x\n",inode->i_dev);
 429         return 1;
 430 }
 431 
 432 int minix_rmdir(struct inode * dir, const char * name, int len)
     /*  */
 433 {
 434         int retval;
 435         struct inode * inode;
 436         struct buffer_head * bh;
 437         struct minix_dir_entry * de;
 438 
 439         inode = NULL;
 440         bh = minix_find_entry(dir,name,len,&de);
 441         retval = -ENOENT;
 442         if (!bh)
 443                 goto end_rmdir;
 444         retval = -EPERM;
 445         if (!(inode = iget(dir->i_sb, de->inode)))
 446                 goto end_rmdir;
 447         if ((dir->i_mode & S_ISVTX) && !fsuser() &&
 448             current->fsuid != inode->i_uid &&
 449             current->fsuid != dir->i_uid)
 450                 goto end_rmdir;
 451         if (inode->i_dev != dir->i_dev)
 452                 goto end_rmdir;
 453         if (inode == dir)       /* we may not delete ".", but "../dir" is ok */
 454                 goto end_rmdir;
 455         if (!S_ISDIR(inode->i_mode)) {
 456                 retval = -ENOTDIR;
 457                 goto end_rmdir;
 458         }
 459         if (!empty_dir(inode)) {
 460                 retval = -ENOTEMPTY;
 461                 goto end_rmdir;
 462         }
 463         if (de->inode != inode->i_ino) {
 464                 retval = -ENOENT;
 465                 goto end_rmdir;
 466         }
 467         if (inode->i_count > 1) {
 468                 retval = -EBUSY;
 469                 goto end_rmdir;
 470         }
 471         if (inode->i_nlink != 2)
 472                 printk("empty directory has nlink!=2 (%d)\n",inode->i_nlink);
 473         de->inode = 0;
 474         dir->i_version = ++event;
 475         mark_buffer_dirty(bh, 1);
 476         inode->i_nlink=0;
 477         inode->i_dirt=1;
 478         inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 479         dir->i_nlink--;
 480         dir->i_dirt=1;
 481         retval = 0;
 482 end_rmdir:
 483         iput(dir);
 484         iput(inode);
 485         brelse(bh);
 486         return retval;
 487 }
 488 
 489 int minix_unlink(struct inode * dir, const char * name, int len)
     /*  */
 490 {
 491         int retval;
 492         struct inode * inode;
 493         struct buffer_head * bh;
 494         struct minix_dir_entry * de;
 495 
 496 repeat:
 497         retval = -ENOENT;
 498         inode = NULL;
 499         bh = minix_find_entry(dir,name,len,&de);
 500         if (!bh)
 501                 goto end_unlink;
 502         if (!(inode = iget(dir->i_sb, de->inode)))
 503                 goto end_unlink;
 504         retval = -EPERM;
 505         if (S_ISDIR(inode->i_mode))
 506                 goto end_unlink;
 507         if (de->inode != inode->i_ino) {
 508                 iput(inode);
 509                 brelse(bh);
 510                 current->counter = 0;
 511                 schedule();
 512                 goto repeat;
 513         }
 514         if ((dir->i_mode & S_ISVTX) && !fsuser() &&
 515             current->fsuid != inode->i_uid &&
 516             current->fsuid != dir->i_uid)
 517                 goto end_unlink;
 518         if (de->inode != inode->i_ino) {
 519                 retval = -ENOENT;
 520                 goto end_unlink;
 521         }
 522         if (!inode->i_nlink) {
 523                 printk("Deleting nonexistent file (%04x:%lu), %d\n",
 524                         inode->i_dev,inode->i_ino,inode->i_nlink);
 525                 inode->i_nlink=1;
 526         }
 527         de->inode = 0;
 528         dir->i_version = ++event;
 529         mark_buffer_dirty(bh, 1);
 530         dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 531         dir->i_dirt = 1;
 532         inode->i_nlink--;
 533         inode->i_ctime = dir->i_ctime;
 534         inode->i_dirt = 1;
 535         retval = 0;
 536 end_unlink:
 537         brelse(bh);
 538         iput(inode);
 539         iput(dir);
 540         return retval;
 541 }
 542 
 543 int minix_symlink(struct inode * dir, const char * name, int len, const char * symname)
     /*  */
 544 {
 545         struct minix_dir_entry * de;
 546         struct inode * inode = NULL;
 547         struct buffer_head * bh = NULL, * name_block = NULL;
 548         int i;
 549         char c;
 550 
 551         if (!(inode = minix_new_inode(dir))) {
 552                 iput(dir);
 553                 return -ENOSPC;
 554         }
 555         inode->i_mode = S_IFLNK | 0777;
 556         inode->i_op = &minix_symlink_inode_operations;
 557         name_block = minix_bread(inode,0,1);
 558         if (!name_block) {
 559                 iput(dir);
 560                 inode->i_nlink--;
 561                 inode->i_dirt = 1;
 562                 iput(inode);
 563                 return -ENOSPC;
 564         }
 565         i = 0;
 566         while (i < 1023 && (c=*(symname++)))
 567                 name_block->b_data[i++] = c;
 568         name_block->b_data[i] = 0;
 569         mark_buffer_dirty(name_block, 1);
 570         brelse(name_block);
 571         inode->i_size = i;
 572         inode->i_dirt = 1;
 573         bh = minix_find_entry(dir,name,len,&de);
 574         if (bh) {
 575                 inode->i_nlink--;
 576                 inode->i_dirt = 1;
 577                 iput(inode);
 578                 brelse(bh);
 579                 iput(dir);
 580                 return -EEXIST;
 581         }
 582         i = minix_add_entry(dir, name, len, &bh, &de);
 583         if (i) {
 584                 inode->i_nlink--;
 585                 inode->i_dirt = 1;
 586                 iput(inode);
 587                 iput(dir);
 588                 return i;
 589         }
 590         de->inode = inode->i_ino;
 591         mark_buffer_dirty(bh, 1);
 592         brelse(bh);
 593         iput(dir);
 594         iput(inode);
 595         return 0;
 596 }
 597 
 598 int minix_link(struct inode * oldinode, struct inode * dir, const char * name, int len)
     /*  */
 599 {
 600         int error;
 601         struct minix_dir_entry * de;
 602         struct buffer_head * bh;
 603 
 604         if (S_ISDIR(oldinode->i_mode)) {
 605                 iput(oldinode);
 606                 iput(dir);
 607                 return -EPERM;
 608         }
 609         if (oldinode->i_nlink >= MINIX_LINK_MAX) {
 610                 iput(oldinode);
 611                 iput(dir);
 612                 return -EMLINK;
 613         }
 614         bh = minix_find_entry(dir,name,len,&de);
 615         if (bh) {
 616                 brelse(bh);
 617                 iput(dir);
 618                 iput(oldinode);
 619                 return -EEXIST;
 620         }
 621         error = minix_add_entry(dir, name, len, &bh, &de);
 622         if (error) {
 623                 iput(dir);
 624                 iput(oldinode);
 625                 return error;
 626         }
 627         de->inode = oldinode->i_ino;
 628         mark_buffer_dirty(bh, 1);
 629         brelse(bh);
 630         iput(dir);
 631         oldinode->i_nlink++;
 632         oldinode->i_ctime = CURRENT_TIME;
 633         oldinode->i_dirt = 1;
 634         iput(oldinode);
 635         return 0;
 636 }
 637 
 638 static int subdir(struct inode * new_inode, struct inode * old_inode)
     /*  */
 639 {
 640         int ino;
 641         int result;
 642 
 643         new_inode->i_count++;
 644         result = 0;
 645         for (;;) {
 646                 if (new_inode == old_inode) {
 647                         result = 1;
 648                         break;
 649                 }
 650                 if (new_inode->i_dev != old_inode->i_dev)
 651                         break;
 652                 ino = new_inode->i_ino;
 653                 if (minix_lookup(new_inode,"..",2,&new_inode))
 654                         break;
 655                 if (new_inode->i_ino == ino)
 656                         break;
 657         }
 658         iput(new_inode);
 659         return result;
 660 }
 661 
 662 #define PARENT_INO(buffer) \
 663 (((struct minix_dir_entry *) ((buffer)+info->s_dirsize))->inode)
 664 
 665 /*
 666  * rename uses retrying to avoid race-conditions: at least they should be minimal.
 667  * it tries to allocate all the blocks, then sanity-checks, and if the sanity-
 668  * checks fail, it tries to restart itself again. Very practical - no changes
 669  * are done until we know everything works ok.. and then all the changes can be
 670  * done in one fell swoop when we have claimed all the buffers needed.
 671  *
 672  * Anybody can rename anything with this: the permission checks are left to the
 673  * higher-level routines.
 674  */
 675 static int do_minix_rename(struct inode * old_dir, const char * old_name, int old_len,
     /*  */
 676         struct inode * new_dir, const char * new_name, int new_len)
 677 {
 678         struct inode * old_inode, * new_inode;
 679         struct buffer_head * old_bh, * new_bh, * dir_bh;
 680         struct minix_dir_entry * old_de, * new_de;
 681         struct minix_sb_info * info;
 682         int retval;
 683 
 684         info = &old_dir->i_sb->u.minix_sb;
 685         goto start_up;
 686 try_again:
 687         brelse(old_bh);
 688         brelse(new_bh);
 689         brelse(dir_bh);
 690         iput(old_inode);
 691         iput(new_inode);
 692         current->counter = 0;
 693         schedule();
 694 start_up:
 695         old_inode = new_inode = NULL;
 696         old_bh = new_bh = dir_bh = NULL;
 697         old_bh = minix_find_entry(old_dir,old_name,old_len,&old_de);
 698         retval = -ENOENT;
 699         if (!old_bh)
 700                 goto end_rename;
 701         old_inode = __iget(old_dir->i_sb, old_de->inode,0); /* don't cross mnt-points */
 702         if (!old_inode)
 703                 goto end_rename;
 704         retval = -EPERM;
 705         if ((old_dir->i_mode & S_ISVTX) && 
 706             current->fsuid != old_inode->i_uid &&
 707             current->fsuid != old_dir->i_uid && !fsuser())
 708                 goto end_rename;
 709         new_bh = minix_find_entry(new_dir,new_name,new_len,&new_de);
 710         if (new_bh) {
 711                 new_inode = __iget(new_dir->i_sb, new_de->inode, 0);
 712                 if (!new_inode) {
 713                         brelse(new_bh);
 714                         new_bh = NULL;
 715                 }
 716         }
 717         if (new_inode == old_inode) {
 718                 retval = 0;
 719                 goto end_rename;
 720         }
 721         if (new_inode && S_ISDIR(new_inode->i_mode)) {
 722                 retval = -EISDIR;
 723                 if (!S_ISDIR(old_inode->i_mode))
 724                         goto end_rename;
 725                 retval = -EINVAL;
 726                 if (subdir(new_dir, old_inode))
 727                         goto end_rename;
 728                 retval = -ENOTEMPTY;
 729                 if (!empty_dir(new_inode))
 730                         goto end_rename;
 731                 retval = -EBUSY;
 732                 if (new_inode->i_count > 1)
 733                         goto end_rename;
 734         }
 735         retval = -EPERM;
 736         if (new_inode && (new_dir->i_mode & S_ISVTX) && 
 737             current->fsuid != new_inode->i_uid &&
 738             current->fsuid != new_dir->i_uid && !fsuser())
 739                 goto end_rename;
 740         if (S_ISDIR(old_inode->i_mode)) {
 741                 retval = -ENOTDIR;
 742                 if (new_inode && !S_ISDIR(new_inode->i_mode))
 743                         goto end_rename;
 744                 retval = -EINVAL;
 745                 if (subdir(new_dir, old_inode))
 746                         goto end_rename;
 747                 retval = -EIO;
 748                 dir_bh = minix_bread(old_inode,0,0);
 749                 if (!dir_bh)
 750                         goto end_rename;
 751                 if (PARENT_INO(dir_bh->b_data) != old_dir->i_ino)
 752                         goto end_rename;
 753                 retval = -EMLINK;
 754                 if (!new_inode && new_dir->i_nlink >= MINIX_LINK_MAX)
 755                         goto end_rename;
 756         }
 757         if (!new_bh) {
 758                 retval = minix_add_entry(new_dir,new_name,new_len,&new_bh,&new_de);
 759                 if (retval)
 760                         goto end_rename;
 761         }
 762 /* sanity checking before doing the rename - avoid races */
 763         if (new_inode && (new_de->inode != new_inode->i_ino))
 764                 goto try_again;
 765         if (new_de->inode && !new_inode)
 766                 goto try_again;
 767         if (old_de->inode != old_inode->i_ino)
 768                 goto try_again;
 769 /* ok, that's it */
 770         old_de->inode = 0;
 771         new_de->inode = old_inode->i_ino;
 772         old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME;
 773         old_dir->i_dirt = 1;
 774         old_dir->i_version = ++event;
 775         new_dir->i_ctime = new_dir->i_mtime = CURRENT_TIME;
 776         new_dir->i_dirt = 1;
 777         new_dir->i_version = ++event;
 778         if (new_inode) {
 779                 new_inode->i_nlink--;
 780                 new_inode->i_ctime = CURRENT_TIME;
 781                 new_inode->i_dirt = 1;
 782         }
 783         mark_buffer_dirty(old_bh, 1);
 784         mark_buffer_dirty(new_bh, 1);
 785         if (dir_bh) {
 786                 PARENT_INO(dir_bh->b_data) = new_dir->i_ino;
 787                 mark_buffer_dirty(dir_bh, 1);
 788                 old_dir->i_nlink--;
 789                 old_dir->i_dirt = 1;
 790                 if (new_inode) {
 791                         new_inode->i_nlink--;
 792                         new_inode->i_dirt = 1;
 793                 } else {
 794                         new_dir->i_nlink++;
 795                         new_dir->i_dirt = 1;
 796                 }
 797         }
 798         retval = 0;
 799 end_rename:
 800         brelse(dir_bh);
 801         brelse(old_bh);
 802         brelse(new_bh);
 803         iput(old_inode);
 804         iput(new_inode);
 805         iput(old_dir);
 806         iput(new_dir);
 807         return retval;
 808 }
 809 
 810 /*
 811  * Ok, rename also locks out other renames, as they can change the parent of
 812  * a directory, and we don't want any races. Other races are checked for by
 813  * "do_rename()", which restarts if there are inconsistencies.
 814  *
 815  * Note that there is no race between different filesystems: it's only within
 816  * the same device that races occur: many renames can happen at once, as long
 817  * as they are on different partitions.
 818  */
 819 int minix_rename(struct inode * old_dir, const char * old_name, int old_len,
     /*  */
 820         struct inode * new_dir, const char * new_name, int new_len)
 821 {
 822         static struct wait_queue * wait = NULL;
 823         static int lock = 0;
 824         int result;
 825 
 826         while (lock)
 827                 sleep_on(&wait);
 828         lock = 1;
 829         result = do_minix_rename(old_dir, old_name, old_len,
 830                 new_dir, new_name, new_len);
 831         lock = 0;
 832         wake_up(&wait);
 833         return result;
 834 }

/* */