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[/] [or1k/] [trunk/] [uclinux/] [uClinux-2.0.x/] [fs/] [minix/] [namei.c] - Blame information for rev 199

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Line No. Rev Author Line
1 199 simons 
/*
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 
                        dir->i_dirt = 1;
193 
                        for (i = 0; i < info->s_namelen ; i++)
194 
                                de->name[i] = (i < namelen) ? name[i] : 0;
195 
                        dir->i_version = ++event;
196 
                        mark_buffer_dirty(bh, 1);
197 
                        *res_dir = de;
198 
                        break;
199 
                }
200 
                if (offset < bh->b_size)
201 
                        continue;
202 
                brelse(bh);
203 
                bh = NULL;
204 
                offset = 0;
205 
                block++;
206 
        }
207 
        *res_buf = bh;
208 
        return 0;
209 
}
210 
 
211 
int minix_create(struct inode * dir,const char * name, int len, int mode,
212 
        struct inode ** result)
213 
{
214 
        int error;
215 
        struct inode * inode;
216 
        struct buffer_head * bh;
217 
        struct minix_dir_entry * de;
218 
 
219 
        *result = NULL;
220 
        if (!dir)
221 
                return -ENOENT;
222 
        inode = minix_new_inode(dir);
223 
        if (!inode) {
224 
                iput(dir);
225 
                return -ENOSPC;
226 
        }
227 
        inode->i_op = &minix_file_inode_operations;
228 
        inode->i_mode = mode;
229 
        inode->i_dirt = 1;
230 
        error = minix_add_entry(dir,name,len, &bh ,&de);
231 
        if (error) {
232 
                inode->i_nlink--;
233 
                inode->i_dirt = 1;
234 
                iput(inode);
235 
                iput(dir);
236 
                return error;
237 
        }
238 
        de->inode = inode->i_ino;
239 
        mark_buffer_dirty(bh, 1);
240 
        brelse(bh);
241 
        iput(dir);
242 
        *result = inode;
243 
        return 0;
244 
}
245 
 
246 
int minix_mknod(struct inode * dir, const char * name, int len, int mode, int rdev)
247 
{
248 
        int error;
249 
        struct inode * inode;
250 
        struct buffer_head * bh;
251 
        struct minix_dir_entry * de;
252 
 
253 
        if (!dir)
254 
                return -ENOENT;
255 
        bh = minix_find_entry(dir,name,len,&de);
256 
        if (bh) {
257 
                brelse(bh);
258 
                iput(dir);
259 
                return -EEXIST;
260 
        }
261 
        inode = minix_new_inode(dir);
262 
        if (!inode) {
263 
                iput(dir);
264 
                return -ENOSPC;
265 
        }
266 
        inode->i_uid = current->fsuid;
267 
        inode->i_mode = mode;
268 
        inode->i_op = NULL;
269 
        if (S_ISREG(inode->i_mode))
270 
                inode->i_op = &minix_file_inode_operations;
271 
        else if (S_ISDIR(inode->i_mode)) {
272 
                inode->i_op = &minix_dir_inode_operations;
273 
                if (dir->i_mode & S_ISGID)
274 
                        inode->i_mode |= S_ISGID;
275 
        }
276 
        else if (S_ISLNK(inode->i_mode))
277 
                inode->i_op = &minix_symlink_inode_operations;
278 
        else if (S_ISCHR(inode->i_mode))
279 
                inode->i_op = &chrdev_inode_operations;
280 
        else if (S_ISBLK(inode->i_mode))
281 
                inode->i_op = &blkdev_inode_operations;
282 
        else if (S_ISFIFO(inode->i_mode))
283 
                init_fifo(inode);
284 
        if (S_ISBLK(mode) || S_ISCHR(mode))
285 
                inode->i_rdev = to_kdev_t(rdev);
286 
        inode->i_dirt = 1;
287 
        error = minix_add_entry(dir, name, len, &bh, &de);
288 
        if (error) {
289 
                inode->i_nlink--;
290 
                inode->i_dirt = 1;
291 
                iput(inode);
292 
                iput(dir);
293 
                return error;
294 
        }
295 
        de->inode = inode->i_ino;
296 
        mark_buffer_dirty(bh, 1);
297 
        brelse(bh);
298 
        iput(dir);
299 
        iput(inode);
300 
        return 0;
301 
}
302 
 
303 
int minix_mkdir(struct inode * dir, const char * name, int len, int mode)
304 
{
305 
        int error;
306 
        struct inode * inode;
307 
        struct buffer_head * bh, *dir_block;
308 
        struct minix_dir_entry * de;
309 
        struct minix_sb_info * info;
310 
 
311 
        if (!dir || !dir->i_sb) {
312 
                iput(dir);
313 
                return -EINVAL;
314 
        }
315 
        info = &dir->i_sb->u.minix_sb;
316 
        bh = minix_find_entry(dir,name,len,&de);
317 
        if (bh) {
318 
                brelse(bh);
319 
                iput(dir);
320 
                return -EEXIST;
321 
        }
322 
        if (dir->i_nlink >= MINIX_LINK_MAX) {
323 
                iput(dir);
324 
                return -EMLINK;
325 
        }
326 
        inode = minix_new_inode(dir);
327 
        if (!inode) {
328 
                iput(dir);
329 
                return -ENOSPC;
330 
        }
331 
        inode->i_op = &minix_dir_inode_operations;
332 
        inode->i_size = 2 * info->s_dirsize;
333 
        dir_block = minix_bread(inode,0,1);
334 
        if (!dir_block) {
335 
                iput(dir);
336 
                inode->i_nlink--;
337 
                inode->i_dirt = 1;
338 
                iput(inode);
339 
                return -ENOSPC;
340 
        }
341 
        de = (struct minix_dir_entry *) dir_block->b_data;
342 
        de->inode=inode->i_ino;
343 
        strcpy(de->name,".");
344 
        de = (struct minix_dir_entry *) (dir_block->b_data + info->s_dirsize);
345 
        de->inode = dir->i_ino;
346 
        strcpy(de->name,"..");
347 
        inode->i_nlink = 2;
348 
        mark_buffer_dirty(dir_block, 1);
349 
        brelse(dir_block);
350 
        inode->i_mode = S_IFDIR | (mode & 0777 & ~current->fs->umask);
351 
        if (dir->i_mode & S_ISGID)
352 
                inode->i_mode |= S_ISGID;
353 
        inode->i_dirt = 1;
354 
        error = minix_add_entry(dir, name, len, &bh, &de);
355 
        if (error) {
356 
                iput(dir);
357 
                inode->i_nlink=0;
358 
                iput(inode);
359 
                return error;
360 
        }
361 
        de->inode = inode->i_ino;
362 
        mark_buffer_dirty(bh, 1);
363 
        dir->i_nlink++;
364 
        dir->i_dirt = 1;
365 
        iput(dir);
366 
        iput(inode);
367 
        brelse(bh);
368 
        return 0;
369 
}
370 
 
371 
/*
372 
 * routine to check that the specified directory is empty (for rmdir)
373 
 */
374 
static int empty_dir(struct inode * inode)
375 
{
376 
        unsigned int block, offset;
377 
        struct buffer_head * bh;
378 
        struct minix_dir_entry * de;
379 
        struct minix_sb_info * info;
380 
 
381 
        if (!inode || !inode->i_sb)
382 
                return 1;
383 
        info = &inode->i_sb->u.minix_sb;
384 
        block = 0;
385 
        bh = NULL;
386 
        offset = 2*info->s_dirsize;
387 
        if (inode->i_size & (info->s_dirsize-1))
388 
                goto bad_dir;
389 
        if (inode->i_size < offset)
390 
                goto bad_dir;
391 
        bh = minix_bread(inode,0,0);
392 
        if (!bh)
393 
                goto bad_dir;
394 
        de = (struct minix_dir_entry *) bh->b_data;
395 
        if (!de->inode || strcmp(de->name,"."))
396 
                goto bad_dir;
397 
        de = (struct minix_dir_entry *) (bh->b_data + info->s_dirsize);
398 
        if (!de->inode || strcmp(de->name,".."))
399 
                goto bad_dir;
400 
        while (block*BLOCK_SIZE+offset < inode->i_size) {
401 
                if (!bh) {
402 
                        bh = minix_bread(inode,block,0);
403 
                        if (!bh) {
404 
                                block++;
405 
                                continue;
406 
                        }
407 
                }
408 
                de = (struct minix_dir_entry *) (bh->b_data + offset);
409 
                offset += info->s_dirsize;
410 
                if (de->inode) {
411 
                        brelse(bh);
412 
                        return 0;
413 
                }
414 
                if (offset < bh->b_size)
415 
                        continue;
416 
                brelse(bh);
417 
                bh = NULL;
418 
                offset = 0;
419 
                block++;
420 
        }
421 
        brelse(bh);
422 
        return 1;
423 
bad_dir:
424 
        brelse(bh);
425 
        printk("Bad directory on device %s\n",
426 
               kdevname(inode->i_dev));
427 
        return 1;
428 
}
429 
 
430 
int minix_rmdir(struct inode * dir, const char * name, int len)
431 
{
432 
        int retval;
433 
        struct inode * inode;
434 
        struct buffer_head * bh;
435 
        struct minix_dir_entry * de;
436 
 
437 
        inode = NULL;
438 
        bh = minix_find_entry(dir,name,len,&de);
439 
        retval = -ENOENT;
440 
        if (!bh)
441 
                goto end_rmdir;
442 
        retval = -EPERM;
443 
        if (!(inode = iget(dir->i_sb, de->inode)))
444 
                goto end_rmdir;
445 
        if ((dir->i_mode & S_ISVTX) && !fsuser() &&
446 
            current->fsuid != inode->i_uid &&
447 
            current->fsuid != dir->i_uid)
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 
        dir->i_version = ++event;
473 
        mark_buffer_dirty(bh, 1);
474 
        inode->i_nlink=0;
475 
        inode->i_dirt=1;
476 
        inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
477 
        dir->i_nlink--;
478 
        dir->i_dirt=1;
479 
        retval = 0;
480 
end_rmdir:
481 
        iput(dir);
482 
        iput(inode);
483 
        brelse(bh);
484 
        return retval;
485 
}
486 
 
487 
int minix_unlink(struct inode * dir, const char * name, int len)
488 
{
489 
        int retval;
490 
        struct inode * inode;
491 
        struct buffer_head * bh;
492 
        struct minix_dir_entry * de;
493 
 
494 
repeat:
495 
        retval = -ENOENT;
496 
        inode = NULL;
497 
        bh = minix_find_entry(dir,name,len,&de);
498 
        if (!bh)
499 
                goto end_unlink;
500 
        if (!(inode = iget(dir->i_sb, de->inode)))
501 
                goto end_unlink;
502 
        retval = -EPERM;
503 
        if (S_ISDIR(inode->i_mode))
504 
                goto end_unlink;
505 
        if (de->inode != inode->i_ino) {
506 
                iput(inode);
507 
                brelse(bh);
508 
                current->counter = 0;
509 
                schedule();
510 
                goto repeat;
511 
        }
512 
        if ((dir->i_mode & S_ISVTX) && !fsuser() &&
513 
            current->fsuid != inode->i_uid &&
514 
            current->fsuid != dir->i_uid)
515 
                goto end_unlink;
516 
        if (de->inode != inode->i_ino) {
517 
                retval = -ENOENT;
518 
                goto end_unlink;
519 
        }
520 
        if (!inode->i_nlink) {
521 
                printk("Deleting nonexistent file (%s:%lu), %d\n",
522 
                        kdevname(inode->i_dev),
523 
                       inode->i_ino, inode->i_nlink);
524 
                inode->i_nlink=1;
525 
        }
526 
        de->inode = 0;
527 
        dir->i_version = ++event;
528 
        mark_buffer_dirty(bh, 1);
529 
        dir->i_ctime = dir->i_mtime = CURRENT_TIME;
530 
        dir->i_dirt = 1;
531 
        inode->i_nlink--;
532 
        inode->i_ctime = dir->i_ctime;
533 
        inode->i_dirt = 1;
534 
        retval = 0;
535 
end_unlink:
536 
        brelse(bh);
537 
        iput(inode);
538 
        iput(dir);
539 
        return retval;
540 
}
541 
 
542 
int minix_symlink(struct inode * dir, const char * name, int len, const char * symname)
543 
{
544 
        struct minix_dir_entry * de;
545 
        struct inode * inode = NULL;
546 
        struct buffer_head * bh = NULL, * name_block = NULL;
547 
        int i;
548 
        char c;
549 
 
550 
        if (!(inode = minix_new_inode(dir))) {
551 
                iput(dir);
552 
                return -ENOSPC;
553 
        }
554 
        inode->i_mode = S_IFLNK | 0777;
555 
        inode->i_op = &minix_symlink_inode_operations;
556 
        name_block = minix_bread(inode,0,1);
557 
        if (!name_block) {
558 
                iput(dir);
559 
                inode->i_nlink--;
560 
                inode->i_dirt = 1;
561 
                iput(inode);
562 
                return -ENOSPC;
563 
        }
564 
        i = 0;
565 
        while (i < 1023 && (c=*(symname++)))
566 
                name_block->b_data[i++] = c;
567 
        name_block->b_data[i] = 0;
568 
        mark_buffer_dirty(name_block, 1);
569 
        brelse(name_block);
570 
        inode->i_size = i;
571 
        inode->i_dirt = 1;
572 
        bh = minix_find_entry(dir,name,len,&de);
573 
        if (bh) {
574 
                inode->i_nlink--;
575 
                inode->i_dirt = 1;
576 
                iput(inode);
577 
                brelse(bh);
578 
                iput(dir);
579 
                return -EEXIST;
580 
        }
581 
        i = minix_add_entry(dir, name, len, &bh, &de);
582 
        if (i) {
583 
                inode->i_nlink--;
584 
                inode->i_dirt = 1;
585 
                iput(inode);
586 
                iput(dir);
587 
                return i;
588 
        }
589 
        de->inode = inode->i_ino;
590 
        mark_buffer_dirty(bh, 1);
591 
        brelse(bh);
592 
        iput(dir);
593 
        iput(inode);
594 
        return 0;
595 
}
596 
 
597 
int minix_link(struct inode * oldinode, struct inode * dir, const char * name, int len)
598 
{
599 
        int error;
600 
        struct minix_dir_entry * de;
601 
        struct buffer_head * bh;
602 
 
603 
        if (S_ISDIR(oldinode->i_mode)) {
604 
                iput(oldinode);
605 
                iput(dir);
606 
                return -EPERM;
607 
        }
608 
        if (oldinode->i_nlink >= MINIX_LINK_MAX) {
609 
                iput(oldinode);
610 
                iput(dir);
611 
                return -EMLINK;
612 
        }
613 
        bh = minix_find_entry(dir,name,len,&de);
614 
        if (bh) {
615 
                brelse(bh);
616 
                iput(dir);
617 
                iput(oldinode);
618 
                return -EEXIST;
619 
        }
620 
        error = minix_add_entry(dir, name, len, &bh, &de);
621 
        if (error) {
622 
                iput(dir);
623 
                iput(oldinode);
624 
                return error;
625 
        }
626 
        de->inode = oldinode->i_ino;
627 
        mark_buffer_dirty(bh, 1);
628 
        brelse(bh);
629 
        iput(dir);
630 
        oldinode->i_nlink++;
631 
        oldinode->i_ctime = CURRENT_TIME;
632 
        oldinode->i_dirt = 1;
633 
        iput(oldinode);
634 
        return 0;
635 
}
636 
 
637 
static int subdir(struct inode * new_inode, struct inode * old_inode)
638 
{
639 
        int ino;
640 
        int result;
641 
 
642 
        new_inode->i_count++;
643 
        result = 0;
644 
        for (;;) {
645 
                if (new_inode == old_inode) {
646 
                        result = 1;
647 
                        break;
648 
                }
649 
                if (new_inode->i_dev != old_inode->i_dev)
650 
                        break;
651 
                ino = new_inode->i_ino;
652 
                if (minix_lookup(new_inode,"..",2,&new_inode))
653 
                        break;
654 
                if (new_inode->i_ino == ino)
655 
                        break;
656 
        }
657 
        iput(new_inode);
658 
        return result;
659 
}
660 
 
661 
#define PARENT_INO(buffer) \
662 
(((struct minix_dir_entry *) ((buffer)+info->s_dirsize))->inode)
663 
 
664 
/*
665 
 * rename uses retrying to avoid race-conditions: at least they should be minimal.
666 
 * it tries to allocate all the blocks, then sanity-checks, and if the sanity-
667 
 * checks fail, it tries to restart itself again. Very practical - no changes
668 
 * are done until we know everything works ok.. and then all the changes can be
669 
 * done in one fell swoop when we have claimed all the buffers needed.
670 
 *
671 
 * Anybody can rename anything with this: the permission checks are left to the
672 
 * higher-level routines.
673 
 */
674 
static int do_minix_rename(struct inode * old_dir, const char * old_name, int old_len,
675 
        struct inode * new_dir, const char * new_name, int new_len, int must_be_dir)
676 
{
677 
        struct inode * old_inode, * new_inode;
678 
        struct buffer_head * old_bh, * new_bh, * dir_bh;
679 
        struct minix_dir_entry * old_de, * new_de;
680 
        struct minix_sb_info * info;
681 
        int retval;
682 
 
683 
        info = &old_dir->i_sb->u.minix_sb;
684 
        goto start_up;
685 
try_again:
686 
        brelse(old_bh);
687 
        brelse(new_bh);
688 
        brelse(dir_bh);
689 
        iput(old_inode);
690 
        iput(new_inode);
691 
        current->counter = 0;
692 
        schedule();
693 
start_up:
694 
        old_inode = new_inode = NULL;
695 
        old_bh = new_bh = dir_bh = NULL;
696 
        old_bh = minix_find_entry(old_dir,old_name,old_len,&old_de);
697 
        retval = -ENOENT;
698 
        if (!old_bh)
699 
                goto end_rename;
700 
        old_inode = __iget(old_dir->i_sb, old_de->inode,0); /* don't cross mnt-points */
701 
        if (!old_inode)
702 
                goto end_rename;
703 
        if (must_be_dir && !S_ISDIR(old_inode->i_mode))
704 
                goto end_rename;
705 
        retval = -EPERM;
706 
        if ((old_dir->i_mode & S_ISVTX) &&
707 
            current->fsuid != old_inode->i_uid &&
708 
            current->fsuid != old_dir->i_uid && !fsuser())
709 
                goto end_rename;
710 
        new_bh = minix_find_entry(new_dir,new_name,new_len,&new_de);
711 
        if (new_bh) {
712 
                new_inode = __iget(new_dir->i_sb, new_de->inode, 0);
713 
                if (!new_inode) {
714 
                        brelse(new_bh);
715 
                        new_bh = NULL;
716 
                }
717 
        }
718 
        if (new_inode == old_inode) {
719 
                retval = 0;
720 
                goto end_rename;
721 
        }
722 
        if (new_inode && S_ISDIR(new_inode->i_mode)) {
723 
                retval = -EISDIR;
724 
                if (!S_ISDIR(old_inode->i_mode))
725 
                        goto end_rename;
726 
                retval = -EINVAL;
727 
                if (subdir(new_dir, old_inode))
728 
                        goto end_rename;
729 
                retval = -ENOTEMPTY;
730 
                if (!empty_dir(new_inode))
731 
                        goto end_rename;
732 
                retval = -EBUSY;
733 
                if (new_inode->i_count > 1)
734 
                        goto end_rename;
735 
        }
736 
        retval = -EPERM;
737 
        if (new_inode && (new_dir->i_mode & S_ISVTX) &&
738 
            current->fsuid != new_inode->i_uid &&
739 
            current->fsuid != new_dir->i_uid && !fsuser())
740 
                goto end_rename;
741 
        if (S_ISDIR(old_inode->i_mode)) {
742 
                retval = -ENOTDIR;
743 
                if (new_inode && !S_ISDIR(new_inode->i_mode))
744 
                        goto end_rename;
745 
                retval = -EINVAL;
746 
                if (subdir(new_dir, old_inode))
747 
                        goto end_rename;
748 
                retval = -EIO;
749 
                dir_bh = minix_bread(old_inode,0,0);
750 
                if (!dir_bh)
751 
                        goto end_rename;
752 
                if (PARENT_INO(dir_bh->b_data) != old_dir->i_ino)
753 
                        goto end_rename;
754 
                retval = -EMLINK;
755 
                if (!new_inode && new_dir->i_nlink >= MINIX_LINK_MAX)
756 
                        goto end_rename;
757 
        }
758 
        if (!new_bh) {
759 
                retval = minix_add_entry(new_dir,new_name,new_len,&new_bh,&new_de);
760 
                if (retval)
761 
                        goto end_rename;
762 
        }
763 
/* sanity checking before doing the rename - avoid races */
764 
        if (new_inode && (new_de->inode != new_inode->i_ino))
765 
                goto try_again;
766 
        if (new_de->inode && !new_inode)
767 
                goto try_again;
768 
        if (old_de->inode != old_inode->i_ino)
769 
                goto try_again;
770 
/* ok, that's it */
771 
        old_de->inode = 0;
772 
        new_de->inode = old_inode->i_ino;
773 
        old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME;
774 
        old_dir->i_dirt = 1;
775 
        old_dir->i_version = ++event;
776 
        new_dir->i_ctime = new_dir->i_mtime = CURRENT_TIME;
777 
        new_dir->i_dirt = 1;
778 
        new_dir->i_version = ++event;
779 
        if (new_inode) {
780 
                new_inode->i_nlink--;
781 
                new_inode->i_ctime = CURRENT_TIME;
782 
                new_inode->i_dirt = 1;
783 
        }
784 
        mark_buffer_dirty(old_bh, 1);
785 
        mark_buffer_dirty(new_bh, 1);
786 
        if (dir_bh) {
787 
                PARENT_INO(dir_bh->b_data) = new_dir->i_ino;
788 
                mark_buffer_dirty(dir_bh, 1);
789 
                old_dir->i_nlink--;
790 
                old_dir->i_dirt = 1;
791 
                if (new_inode) {
792 
                        new_inode->i_nlink--;
793 
                        new_inode->i_dirt = 1;
794 
                } else {
795 
                        new_dir->i_nlink++;
796 
                        new_dir->i_dirt = 1;
797 
                }
798 
        }
799 
        retval = 0;
800 
end_rename:
801 
        brelse(dir_bh);
802 
        brelse(old_bh);
803 
        brelse(new_bh);
804 
        iput(old_inode);
805 
        iput(new_inode);
806 
        iput(old_dir);
807 
        iput(new_dir);
808 
        return retval;
809 
}
810 
 
811 
/*
812 
 * Ok, rename also locks out other renames, as they can change the parent of
813 
 * a directory, and we don't want any races. Other races are checked for by
814 
 * "do_rename()", which restarts if there are inconsistencies.
815 
 *
816 
 * Note that there is no race between different filesystems: it's only within
817 
 * the same device that races occur: many renames can happen at once, as long
818 
 * as they are on different partitions.
819 
 */
820 
int minix_rename(struct inode * old_dir, const char * old_name, int old_len,
821 
        struct inode * new_dir, const char * new_name, int new_len,
822 
        int must_be_dir)
823 
{
824 
        static struct wait_queue * wait = NULL;
825 
        static int lock = 0;
826 
        int result;
827 
 
828 
        while (lock)
829 
                sleep_on(&wait);
830 
        lock = 1;
831 
        result = do_minix_rename(old_dir, old_name, old_len,
832 
                new_dir, new_name, new_len, must_be_dir);
833 
        lock = 0;
834 
        wake_up(&wait);
835 
        return result;
836 
}

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