1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
|
/*
* linux/fs/ext2/namei.c
*
* Copyright (C) 1992, 1993, 1994, 1995
* Remy Card (card@masi.ibp.fr)
* Laboratoire MASI - Institut Blaise Pascal
* Universite Pierre et Marie Curie (Paris VI)
*
* from
*
* linux/fs/minix/namei.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*
* Big-endian to little-endian byte-swapping/bitmaps by
* David S. Miller (davem@caip.rutgers.edu), 1995
* Directory entry file type support and forward compatibility hooks
* for B-tree directories by Theodore Ts'o (tytso@mit.edu), 1998
*/
#include <linux/fs.h>
#include <linux/locks.h>
#include <linux/quotaops.h>
/*
* define how far ahead to read directories while searching them.
*/
#define NAMEI_RA_CHUNKS 2
#define NAMEI_RA_BLOCKS 4
#define NAMEI_RA_SIZE (NAMEI_RA_CHUNKS * NAMEI_RA_BLOCKS)
#define NAMEI_RA_INDEX(c,b) (((c) * NAMEI_RA_BLOCKS) + (b))
/*
* NOTE! unlike strncmp, ext2_match returns 1 for success, 0 for failure.
*
* `len <= EXT2_NAME_LEN' is guaranteed by caller.
* `de != NULL' is guaranteed by caller.
*/
static inline int ext2_match (int len, const char * const name,
struct ext2_dir_entry_2 * de)
{
if (len != de->name_len)
return 0;
if (!de->inode)
return 0;
return !memcmp(name, de->name, len);
}
/*
* ext2_find_entry()
*
* finds an entry in the specified directory with the wanted name. It
* returns the cache buffer in which the entry was found, and the entry
* itself (as a parameter - res_dir). It does NOT read the inode of the
* entry - you'll have to do that yourself if you want to.
*/
static struct buffer_head * ext2_find_entry (struct inode * dir,
const char * const name, int namelen,
struct ext2_dir_entry_2 ** res_dir)
{
struct super_block * sb;
struct buffer_head * bh_use[NAMEI_RA_SIZE];
struct buffer_head * bh_read[NAMEI_RA_SIZE];
unsigned long offset;
int block, toread, i, err;
*res_dir = NULL;
sb = dir->i_sb;
if (namelen > EXT2_NAME_LEN)
return NULL;
memset (bh_use, 0, sizeof (bh_use));
toread = 0;
for (block = 0; block < NAMEI_RA_SIZE; ++block) {
struct buffer_head * bh;
if ((block << EXT2_BLOCK_SIZE_BITS (sb)) >= dir->i_size)
break;
bh = ext2_getblk (dir, block, 0, &err);
bh_use[block] = bh;
if (bh && !buffer_uptodate(bh))
bh_read[toread++] = bh;
}
for (block = 0, offset = 0; offset < dir->i_size; block++) {
struct buffer_head * bh;
struct ext2_dir_entry_2 * de;
char * dlimit;
if ((block % NAMEI_RA_BLOCKS) == 0 && toread) {
ll_rw_block (READ, toread, bh_read);
toread = 0;
}
bh = bh_use[block % NAMEI_RA_SIZE];
if (!bh) {
#if 0
ext2_error (sb, "ext2_find_entry",
"directory #%lu contains a hole at offset %lu",
dir->i_ino, offset);
#endif
offset += sb->s_blocksize;
continue;
}
wait_on_buffer (bh);
if (!buffer_uptodate(bh)) {
/*
* read error: all bets are off
*/
break;
}
de = (struct ext2_dir_entry_2 *) bh->b_data;
dlimit = bh->b_data + sb->s_blocksize;
while ((char *) de < dlimit) {
/* this code is executed quadratically often */
/* do minimal checking `by hand' */
int de_len;
if ((char *) de + namelen <= dlimit &&
ext2_match (namelen, name, de)) {
/* found a match -
just to be sure, do a full check */
if (!ext2_check_dir_entry("ext2_find_entry",
dir, de, bh, offset))
goto failure;
for (i = 0; i < NAMEI_RA_SIZE; ++i) {
if (bh_use[i] != bh)
brelse (bh_use[i]);
}
*res_dir = de;
return bh;
}
/* prevent looping on a bad block */
de_len = le16_to_cpu(de->rec_len);
if (de_len <= 0)
goto failure;
offset += de_len;
de = (struct ext2_dir_entry_2 *)
((char *) de + de_len);
}
brelse (bh);
if (((block + NAMEI_RA_SIZE) << EXT2_BLOCK_SIZE_BITS (sb)) >=
dir->i_size)
bh = NULL;
else
bh = ext2_getblk (dir, block + NAMEI_RA_SIZE, 0, &err);
bh_use[block % NAMEI_RA_SIZE] = bh;
if (bh && !buffer_uptodate(bh))
bh_read[toread++] = bh;
}
failure:
for (i = 0; i < NAMEI_RA_SIZE; ++i)
brelse (bh_use[i]);
return NULL;
}
static struct dentry *ext2_lookup(struct inode * dir, struct dentry *dentry)
{
struct inode * inode;
struct ext2_dir_entry_2 * de;
struct buffer_head * bh;
if (dentry->d_name.len > EXT2_NAME_LEN)
return ERR_PTR(-ENAMETOOLONG);
bh = ext2_find_entry (dir, dentry->d_name.name, dentry->d_name.len, &de);
inode = NULL;
if (bh) {
unsigned long ino = le32_to_cpu(de->inode);
brelse (bh);
inode = iget(dir->i_sb, ino);
if (!inode)
return ERR_PTR(-EACCES);
}
d_add(dentry, inode);
return NULL;
}
static inline void ext2_set_de_type(struct super_block *sb,
struct ext2_dir_entry_2 *de,
umode_t mode) {
if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_FILETYPE))
return;
if (S_ISREG(mode))
de->file_type = EXT2_FT_REG_FILE;
else if (S_ISDIR(mode))
de->file_type = EXT2_FT_DIR;
else if (S_ISLNK(mode))
de->file_type = EXT2_FT_SYMLINK;
else if (S_ISSOCK(mode))
de->file_type = EXT2_FT_SOCK;
else if (S_ISFIFO(mode))
de->file_type = EXT2_FT_FIFO;
else if (S_ISCHR(mode))
de->file_type = EXT2_FT_CHRDEV;
else if (S_ISBLK(mode))
de->file_type = EXT2_FT_BLKDEV;
}
/*
* ext2_add_entry()
*
* adds a file entry to the specified directory.
*/
int ext2_add_entry (struct inode * dir, const char * name, int namelen,
struct inode *inode)
{
unsigned long offset;
unsigned short rec_len;
struct buffer_head * bh;
struct ext2_dir_entry_2 * de, * de1;
struct super_block * sb;
int retval;
sb = dir->i_sb;
if (!namelen)
return -EINVAL;
bh = ext2_bread (dir, 0, 0, &retval);
if (!bh)
return retval;
rec_len = EXT2_DIR_REC_LEN(namelen);
offset = 0;
de = (struct ext2_dir_entry_2 *) bh->b_data;
while (1) {
if ((char *)de >= sb->s_blocksize + bh->b_data) {
brelse (bh);
bh = NULL;
bh = ext2_bread (dir, offset >> EXT2_BLOCK_SIZE_BITS(sb), 1, &retval);
if (!bh)
return retval;
if (dir->i_size <= offset) {
if (dir->i_size == 0) {
return -ENOENT;
}
ext2_debug ("creating next block\n");
de = (struct ext2_dir_entry_2 *) bh->b_data;
de->inode = 0;
de->rec_len = le16_to_cpu(sb->s_blocksize);
dir->i_size = offset + sb->s_blocksize;
dir->u.ext2_i.i_flags &= ~EXT2_BTREE_FL;
mark_inode_dirty(dir);
} else {
ext2_debug ("skipping to next block\n");
de = (struct ext2_dir_entry_2 *) bh->b_data;
}
}
if (!ext2_check_dir_entry ("ext2_add_entry", dir, de, bh,
offset)) {
brelse (bh);
return -ENOENT;
}
if (ext2_match (namelen, name, de)) {
brelse (bh);
return -EEXIST;
}
if ((le32_to_cpu(de->inode) == 0 && le16_to_cpu(de->rec_len) >= rec_len) ||
(le16_to_cpu(de->rec_len) >= EXT2_DIR_REC_LEN(de->name_len) + rec_len)) {
offset += le16_to_cpu(de->rec_len);
if (le32_to_cpu(de->inode)) {
de1 = (struct ext2_dir_entry_2 *) ((char *) de +
EXT2_DIR_REC_LEN(de->name_len));
de1->rec_len = cpu_to_le16(le16_to_cpu(de->rec_len) -
EXT2_DIR_REC_LEN(de->name_len));
de->rec_len = cpu_to_le16(EXT2_DIR_REC_LEN(de->name_len));
de = de1;
}
de->file_type = EXT2_FT_UNKNOWN;
if (inode) {
de->inode = cpu_to_le32(inode->i_ino);
ext2_set_de_type(dir->i_sb, de, inode->i_mode);
} else
de->inode = 0;
de->name_len = namelen;
memcpy (de->name, name, namelen);
/*
* XXX shouldn't update any times until successful
* completion of syscall, but too many callers depend
* on this.
*
* XXX similarly, too many callers depend on
* ext2_new_inode() setting the times, but error
* recovery deletes the inode, so the worst that can
* happen is that the times are slightly out of date
* and/or different from the directory change time.
*/
dir->i_mtime = dir->i_ctime = CURRENT_TIME;
dir->u.ext2_i.i_flags &= ~EXT2_BTREE_FL;
mark_inode_dirty(dir);
dir->i_version = ++event;
mark_buffer_dirty(bh, 1);
if (IS_SYNC(dir)) {
ll_rw_block (WRITE, 1, &bh);
wait_on_buffer (bh);
}
brelse(bh);
return 0;
}
offset += le16_to_cpu(de->rec_len);
de = (struct ext2_dir_entry_2 *) ((char *) de + le16_to_cpu(de->rec_len));
}
brelse (bh);
return -ENOSPC;
}
/*
* ext2_delete_entry deletes a directory entry by merging it with the
* previous entry
*/
static int ext2_delete_entry (struct inode * dir,
struct ext2_dir_entry_2 * de_del,
struct buffer_head * bh)
{
struct ext2_dir_entry_2 * de, * pde;
int i;
i = 0;
pde = NULL;
de = (struct ext2_dir_entry_2 *) bh->b_data;
while (i < bh->b_size) {
if (!ext2_check_dir_entry ("ext2_delete_entry", NULL,
de, bh, i))
return -EIO;
if (de == de_del) {
if (pde)
pde->rec_len =
cpu_to_le16(le16_to_cpu(pde->rec_len) +
le16_to_cpu(de->rec_len));
else
de->inode = 0;
dir->i_version = ++event;
mark_buffer_dirty(bh, 1);
if (IS_SYNC(dir)) {
ll_rw_block (WRITE, 1, &bh);
wait_on_buffer (bh);
}
return 0;
}
i += le16_to_cpu(de->rec_len);
pde = de;
de = (struct ext2_dir_entry_2 *) ((char *) de + le16_to_cpu(de->rec_len));
}
return -ENOENT;
}
/*
* By the time this is called, we already have created
* the directory cache entry for the new file, but it
* is so far negative - it has no inode.
*
* If the create succeeds, we fill in the inode information
* with d_instantiate().
*/
static int ext2_create (struct inode * dir, struct dentry * dentry, int mode)
{
struct inode * inode;
int err;
/*
* N.B. Several error exits in ext2_new_inode don't set err.
*/
inode = ext2_new_inode (dir, mode, &err);
if (!inode)
return -EIO;
inode->i_op = &ext2_file_inode_operations;
inode->i_fop = &ext2_file_operations;
inode->i_mapping->a_ops = &ext2_aops;
inode->i_mode = mode;
mark_inode_dirty(inode);
err = ext2_add_entry (dir, dentry->d_name.name, dentry->d_name.len,
inode);
if (err) {
inode->i_nlink--;
mark_inode_dirty(inode);
iput (inode);
return err;
}
d_instantiate(dentry, inode);
return 0;
}
static int ext2_mknod (struct inode * dir, struct dentry *dentry, int mode, int rdev)
{
struct inode * inode;
int err;
inode = ext2_new_inode (dir, mode, &err);
if (!inode)
return -EIO;
inode->i_uid = current->fsuid;
init_special_inode(inode, mode, rdev);
err = ext2_add_entry (dir, dentry->d_name.name, dentry->d_name.len,
inode);
if (err)
goto out_no_entry;
mark_inode_dirty(inode);
d_instantiate(dentry, inode);
return 0;
out_no_entry:
inode->i_nlink--;
mark_inode_dirty(inode);
iput(inode);
return err;
}
static int ext2_mkdir(struct inode * dir, struct dentry * dentry, int mode)
{
struct inode * inode;
struct buffer_head * dir_block;
struct ext2_dir_entry_2 * de;
int err;
if (dir->i_nlink >= EXT2_LINK_MAX)
return -EMLINK;
inode = ext2_new_inode (dir, S_IFDIR, &err);
if (!inode)
return -EIO;
inode->i_op = &ext2_dir_inode_operations;
inode->i_fop = &ext2_dir_operations;
inode->i_size = inode->i_sb->s_blocksize;
inode->i_blocks = 0;
dir_block = ext2_bread (inode, 0, 1, &err);
if (!dir_block) {
inode->i_nlink--; /* is this nlink == 0? */
mark_inode_dirty(inode);
iput (inode);
return -EIO;
}
de = (struct ext2_dir_entry_2 *) dir_block->b_data;
de->inode = cpu_to_le32(inode->i_ino);
de->name_len = 1;
de->rec_len = cpu_to_le16(EXT2_DIR_REC_LEN(de->name_len));
strcpy (de->name, ".");
ext2_set_de_type(dir->i_sb, de, S_IFDIR);
de = (struct ext2_dir_entry_2 *) ((char *) de + le16_to_cpu(de->rec_len));
de->inode = cpu_to_le32(dir->i_ino);
de->rec_len = cpu_to_le16(inode->i_sb->s_blocksize - EXT2_DIR_REC_LEN(1));
de->name_len = 2;
strcpy (de->name, "..");
ext2_set_de_type(dir->i_sb, de, S_IFDIR);
inode->i_nlink = 2;
mark_buffer_dirty(dir_block, 1);
brelse (dir_block);
inode->i_mode = S_IFDIR | mode;
if (dir->i_mode & S_ISGID)
inode->i_mode |= S_ISGID;
mark_inode_dirty(inode);
err = ext2_add_entry (dir, dentry->d_name.name, dentry->d_name.len,
inode);
if (err)
goto out_no_entry;
dir->i_nlink++;
dir->u.ext2_i.i_flags &= ~EXT2_BTREE_FL;
mark_inode_dirty(dir);
d_instantiate(dentry, inode);
return 0;
out_no_entry:
inode->i_nlink = 0;
mark_inode_dirty(inode);
iput (inode);
return err;
}
/*
* routine to check that the specified directory is empty (for rmdir)
*/
static int empty_dir (struct inode * inode)
{
unsigned long offset;
struct buffer_head * bh;
struct ext2_dir_entry_2 * de, * de1;
struct super_block * sb;
int err;
sb = inode->i_sb;
if (inode->i_size < EXT2_DIR_REC_LEN(1) + EXT2_DIR_REC_LEN(2) ||
!(bh = ext2_bread (inode, 0, 0, &err))) {
ext2_warning (inode->i_sb, "empty_dir",
"bad directory (dir #%lu) - no data block",
inode->i_ino);
return 1;
}
de = (struct ext2_dir_entry_2 *) bh->b_data;
de1 = (struct ext2_dir_entry_2 *) ((char *) de + le16_to_cpu(de->rec_len));
if (le32_to_cpu(de->inode) != inode->i_ino || !le32_to_cpu(de1->inode) ||
strcmp (".", de->name) || strcmp ("..", de1->name)) {
ext2_warning (inode->i_sb, "empty_dir",
"bad directory (dir #%lu) - no `.' or `..'",
inode->i_ino);
brelse (bh);
return 1;
}
offset = le16_to_cpu(de->rec_len) + le16_to_cpu(de1->rec_len);
de = (struct ext2_dir_entry_2 *) ((char *) de1 + le16_to_cpu(de1->rec_len));
while (offset < inode->i_size ) {
if (!bh || (void *) de >= (void *) (bh->b_data + sb->s_blocksize)) {
brelse (bh);
bh = ext2_bread (inode, offset >> EXT2_BLOCK_SIZE_BITS(sb), 0, &err);
if (!bh) {
#if 0
ext2_error (sb, "empty_dir",
"directory #%lu contains a hole at offset %lu",
inode->i_ino, offset);
#endif
offset += sb->s_blocksize;
continue;
}
de = (struct ext2_dir_entry_2 *) bh->b_data;
}
if (!ext2_check_dir_entry ("empty_dir", inode, de, bh,
offset)) {
brelse (bh);
return 1;
}
if (le32_to_cpu(de->inode)) {
brelse (bh);
return 0;
}
offset += le16_to_cpu(de->rec_len);
de = (struct ext2_dir_entry_2 *) ((char *) de + le16_to_cpu(de->rec_len));
}
brelse (bh);
return 1;
}
static int ext2_rmdir (struct inode * dir, struct dentry *dentry)
{
int retval;
struct inode * inode;
struct buffer_head * bh;
struct ext2_dir_entry_2 * de;
retval = -ENOENT;
bh = ext2_find_entry (dir, dentry->d_name.name, dentry->d_name.len, &de);
if (!bh)
goto end_rmdir;
inode = dentry->d_inode;
DQUOT_INIT(inode);
retval = -EIO;
if (le32_to_cpu(de->inode) != inode->i_ino)
goto end_rmdir;
retval = -ENOTEMPTY;
if (!empty_dir (inode))
goto end_rmdir;
retval = ext2_delete_entry(dir, de, bh);
if (retval)
goto end_rmdir;
if (inode->i_nlink != 2)
ext2_warning (inode->i_sb, "ext2_rmdir",
"empty directory has nlink!=2 (%d)",
inode->i_nlink);
inode->i_version = ++event;
inode->i_nlink = 0;
inode->i_size = 0;
mark_inode_dirty(inode);
dir->i_nlink--;
inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
dir->u.ext2_i.i_flags &= ~EXT2_BTREE_FL;
mark_inode_dirty(dir);
end_rmdir:
brelse (bh);
return retval;
}
static int ext2_unlink(struct inode * dir, struct dentry *dentry)
{
int retval;
struct inode * inode;
struct buffer_head * bh;
struct ext2_dir_entry_2 * de;
retval = -ENOENT;
bh = ext2_find_entry (dir, dentry->d_name.name, dentry->d_name.len, &de);
if (!bh)
goto end_unlink;
inode = dentry->d_inode;
DQUOT_INIT(inode);
retval = -EIO;
if (le32_to_cpu(de->inode) != inode->i_ino)
goto end_unlink;
if (!inode->i_nlink) {
ext2_warning (inode->i_sb, "ext2_unlink",
"Deleting nonexistent file (%lu), %d",
inode->i_ino, inode->i_nlink);
inode->i_nlink = 1;
}
retval = ext2_delete_entry(dir, de, bh);
if (retval)
goto end_unlink;
dir->i_ctime = dir->i_mtime = CURRENT_TIME;
dir->u.ext2_i.i_flags &= ~EXT2_BTREE_FL;
mark_inode_dirty(dir);
inode->i_nlink--;
mark_inode_dirty(inode);
inode->i_ctime = dir->i_ctime;
retval = 0;
end_unlink:
brelse (bh);
return retval;
}
static int ext2_symlink (struct inode * dir, struct dentry *dentry, const char * symname)
{
struct inode * inode;
int l, err;
l = strlen(symname)+1;
if (l > dir->i_sb->s_blocksize)
return -ENAMETOOLONG;
if (!(inode = ext2_new_inode (dir, S_IFLNK, &err)))
return -EIO;
inode->i_mode = S_IFLNK | S_IRWXUGO;
if (l > sizeof (inode->u.ext2_i.i_data)) {
inode->i_op = &page_symlink_inode_operations;
inode->i_mapping->a_ops = &ext2_aops;
err = block_symlink(inode, symname, l);
if (err)
goto out_no_entry;
} else {
inode->i_op = &ext2_fast_symlink_inode_operations;
memcpy((char*)&inode->u.ext2_i.i_data,symname,l);
inode->i_size = l-1;
}
mark_inode_dirty(inode);
err = ext2_add_entry (dir, dentry->d_name.name, dentry->d_name.len,
inode);
if (err)
goto out_no_entry;
d_instantiate(dentry, inode);
return 0;
out_no_entry:
inode->i_nlink--;
mark_inode_dirty(inode);
iput (inode);
return err;
}
static int ext2_link (struct dentry * old_dentry,
struct inode * dir, struct dentry *dentry)
{
struct inode *inode = old_dentry->d_inode;
int err;
if (S_ISDIR(inode->i_mode))
return -EPERM;
if (inode->i_nlink >= EXT2_LINK_MAX)
return -EMLINK;
err = ext2_add_entry (dir, dentry->d_name.name, dentry->d_name.len,
inode);
if (err)
return err;
inode->i_nlink++;
inode->i_ctime = CURRENT_TIME;
mark_inode_dirty(inode);
atomic_inc(&inode->i_count);
d_instantiate(dentry, inode);
return 0;
}
#define PARENT_INO(buffer) \
((struct ext2_dir_entry_2 *) ((char *) buffer + \
le16_to_cpu(((struct ext2_dir_entry_2 *) buffer)->rec_len)))->inode
/*
* Anybody can rename anything with this: the permission checks are left to the
* higher-level routines.
*/
static int ext2_rename (struct inode * old_dir, struct dentry *old_dentry,
struct inode * new_dir,struct dentry *new_dentry)
{
struct inode * old_inode, * new_inode;
struct buffer_head * old_bh, * new_bh, * dir_bh;
struct ext2_dir_entry_2 * old_de, * new_de;
int retval;
old_bh = new_bh = dir_bh = NULL;
old_bh = ext2_find_entry (old_dir, old_dentry->d_name.name, old_dentry->d_name.len, &old_de);
/*
* Check for inode number is _not_ due to possible IO errors.
* We might rmdir the source, keep it as pwd of some process
* and merrily kill the link to whatever was created under the
* same name. Goodbye sticky bit ;-<
*/
old_inode = old_dentry->d_inode;
retval = -ENOENT;
if (!old_bh || le32_to_cpu(old_de->inode) != old_inode->i_ino)
goto end_rename;
new_inode = new_dentry->d_inode;
new_bh = ext2_find_entry (new_dir, new_dentry->d_name.name,
new_dentry->d_name.len, &new_de);
if (new_bh) {
if (!new_inode) {
brelse (new_bh);
new_bh = NULL;
} else {
DQUOT_INIT(new_inode);
}
}
if (S_ISDIR(old_inode->i_mode)) {
if (new_inode) {
retval = -ENOTEMPTY;
if (!empty_dir (new_inode))
goto end_rename;
}
retval = -EIO;
dir_bh = ext2_bread (old_inode, 0, 0, &retval);
if (!dir_bh)
goto end_rename;
if (le32_to_cpu(PARENT_INO(dir_bh->b_data)) != old_dir->i_ino)
goto end_rename;
retval = -EMLINK;
if (!new_inode && new_dir!=old_dir &&
new_dir->i_nlink >= EXT2_LINK_MAX)
goto end_rename;
}
if (!new_bh) {
retval = ext2_add_entry (new_dir, new_dentry->d_name.name,
new_dentry->d_name.len,
old_inode);
if (retval)
goto end_rename;
} else {
new_de->inode = le32_to_cpu(old_inode->i_ino);
if (EXT2_HAS_INCOMPAT_FEATURE(new_dir->i_sb,
EXT2_FEATURE_INCOMPAT_FILETYPE))
new_de->file_type = old_de->file_type;
new_dir->i_version = ++event;
mark_buffer_dirty(new_bh, 1);
if (IS_SYNC(new_dir)) {
ll_rw_block (WRITE, 1, &new_bh);
wait_on_buffer (new_bh);
}
brelse(new_bh);
new_bh = NULL;
}
/*
* Like most other Unix systems, set the ctime for inodes on a
* rename.
*/
old_inode->i_ctime = CURRENT_TIME;
mark_inode_dirty(old_inode);
/*
* ok, that's it
*/
ext2_delete_entry(old_dir, old_de, old_bh);
if (new_inode) {
new_inode->i_nlink--;
new_inode->i_ctime = CURRENT_TIME;
mark_inode_dirty(new_inode);
}
old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME;
old_dir->u.ext2_i.i_flags &= ~EXT2_BTREE_FL;
mark_inode_dirty(old_dir);
if (dir_bh) {
PARENT_INO(dir_bh->b_data) = le32_to_cpu(new_dir->i_ino);
mark_buffer_dirty(dir_bh, 1);
old_dir->i_nlink--;
mark_inode_dirty(old_dir);
if (new_inode) {
new_inode->i_nlink--;
mark_inode_dirty(new_inode);
} else {
new_dir->i_nlink++;
new_dir->u.ext2_i.i_flags &= ~EXT2_BTREE_FL;
mark_inode_dirty(new_dir);
}
}
retval = 0;
end_rename:
brelse (dir_bh);
brelse (old_bh);
brelse (new_bh);
return retval;
}
/*
* directories can handle most operations...
*/
struct inode_operations ext2_dir_inode_operations = {
create: ext2_create,
lookup: ext2_lookup,
link: ext2_link,
unlink: ext2_unlink,
symlink: ext2_symlink,
mkdir: ext2_mkdir,
rmdir: ext2_rmdir,
mknod: ext2_mknod,
rename: ext2_rename,
};
|