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Linux v2.6.15-rc7
[pohmelfs.git] / fs / ufs / dir.c
blobd0915fba155a598f0a7d0d602a5d299e96835647
1 /*
2 * linux/fs/ufs/ufs_dir.c
3 *
4 * Copyright (C) 1996
5 * Adrian Rodriguez (adrian@franklins-tower.rutgers.edu)
6 * Laboratory for Computer Science Research Computing Facility
7 * Rutgers, The State University of New Jersey
8 *
9 * swab support by Francois-Rene Rideau <fare@tunes.org> 19970406
10 *
11 * 4.4BSD (FreeBSD) support added on February 1st 1998 by
12 * Niels Kristian Bech Jensen <nkbj@image.dk> partially based
13 * on code by Martin von Loewis <martin@mira.isdn.cs.tu-berlin.de>.
14 */
15
16 #include <linux/time.h>
17 #include <linux/fs.h>
18 #include <linux/ufs_fs.h>
19 #include <linux/smp_lock.h>
20 #include <linux/buffer_head.h>
21 #include <linux/sched.h>
22
23 #include "swab.h"
24 #include "util.h"
25
26 #undef UFS_DIR_DEBUG
27
28 #ifdef UFS_DIR_DEBUG
29 #define UFSD(x) printk("(%s, %d), %s: ", __FILE__, __LINE__, __FUNCTION__); printk x;
30 #else
31 #define UFSD(x)
32 #endif
33
34 static int
35 ufs_check_dir_entry (const char *, struct inode *, struct ufs_dir_entry *,
36 struct buffer_head *, unsigned long);
37
38
39 /*
40 * NOTE! unlike strncmp, ufs_match returns 1 for success, 0 for failure.
41 *
42 * len <= UFS_MAXNAMLEN and de != NULL are guaranteed by caller.
43 */
44 static inline int ufs_match(struct super_block *sb, int len,
45 const char * const name, struct ufs_dir_entry * de)
46 {
47 if (len != ufs_get_de_namlen(sb, de))
48 return 0;
49 if (!de->d_ino)
50 return 0;
51 return !memcmp(name, de->d_name, len);
52 }
53
54 /*
55 * This is blatantly stolen from ext2fs
56 */
57 static int
58 ufs_readdir (struct file * filp, void * dirent, filldir_t filldir)
59 {
60 struct inode *inode = filp->f_dentry->d_inode;
61 int error = 0;
62 unsigned long offset, lblk;
63 int i, stored;
64 struct buffer_head * bh;
65 struct ufs_dir_entry * de;
66 struct super_block * sb;
67 int de_reclen;
68 unsigned flags;
69 u64 blk= 0L;
70
71 lock_kernel();
72
73 sb = inode->i_sb;
74 flags = UFS_SB(sb)->s_flags;
75
76 UFSD(("ENTER, ino %lu f_pos %lu\n", inode->i_ino, (unsigned long) filp->f_pos))
77
78 stored = 0;
79 bh = NULL;
80 offset = filp->f_pos & (sb->s_blocksize - 1);
81
82 while (!error && !stored && filp->f_pos < inode->i_size) {
83 lblk = (filp->f_pos) >> sb->s_blocksize_bits;
84 blk = ufs_frag_map(inode, lblk);
85 if (!blk || !(bh = sb_bread(sb, blk))) {
86 /* XXX - error - skip to the next block */
87 printk("ufs_readdir: "
88 "dir inode %lu has a hole at offset %lu\n",
89 inode->i_ino, (unsigned long int)filp->f_pos);
90 filp->f_pos += sb->s_blocksize - offset;
91 continue;
92 }
93
94 revalidate:
95 /* If the dir block has changed since the last call to
96 * readdir(2), then we might be pointing to an invalid
97 * dirent right now. Scan from the start of the block
98 * to make sure. */
99 if (filp->f_version != inode->i_version) {
100 for (i = 0; i < sb->s_blocksize && i < offset; ) {
101 de = (struct ufs_dir_entry *)(bh->b_data + i);
102 /* It's too expensive to do a full
103 * dirent test each time round this
104 * loop, but we do have to test at
105 * least that it is non-zero. A
106 * failure will be detected in the
107 * dirent test below. */
108 de_reclen = fs16_to_cpu(sb, de->d_reclen);
109 if (de_reclen < 1)
110 break;
111 i += de_reclen;
112 }
113 offset = i;
114 filp->f_pos = (filp->f_pos & ~(sb->s_blocksize - 1))
115 | offset;
116 filp->f_version = inode->i_version;
117 }
118
119 while (!error && filp->f_pos < inode->i_size
120 && offset < sb->s_blocksize) {
121 de = (struct ufs_dir_entry *) (bh->b_data + offset);
122 /* XXX - put in a real ufs_check_dir_entry() */
123 if ((de->d_reclen == 0) || (ufs_get_de_namlen(sb, de) == 0)) {
124 filp->f_pos = (filp->f_pos &
125 (sb->s_blocksize - 1)) +
126 sb->s_blocksize;
127 brelse(bh);
128 unlock_kernel();
129 return stored;
130 }
131 if (!ufs_check_dir_entry ("ufs_readdir", inode, de,
132 bh, offset)) {
133 /* On error, skip the f_pos to the
134 next block. */
135 filp->f_pos = (filp->f_pos |
136 (sb->s_blocksize - 1)) +
137 1;
138 brelse (bh);
139 unlock_kernel();
140 return stored;
141 }
142 offset += fs16_to_cpu(sb, de->d_reclen);
143 if (de->d_ino) {
144 /* We might block in the next section
145 * if the data destination is
146 * currently swapped out. So, use a
147 * version stamp to detect whether or
148 * not the directory has been modified
149 * during the copy operation. */
150 unsigned long version = filp->f_version;
151 unsigned char d_type = DT_UNKNOWN;
152
153 UFSD(("filldir(%s,%u)\n", de->d_name,
154 fs32_to_cpu(sb, de->d_ino)))
155 UFSD(("namlen %u\n", ufs_get_de_namlen(sb, de)))
156
157 if ((flags & UFS_DE_MASK) == UFS_DE_44BSD)
158 d_type = de->d_u.d_44.d_type;
159 error = filldir(dirent, de->d_name,
160 ufs_get_de_namlen(sb, de), filp->f_pos,
161 fs32_to_cpu(sb, de->d_ino), d_type);
162 if (error)
163 break;
164 if (version != filp->f_version)
165 goto revalidate;
166 stored ++;
167 }
168 filp->f_pos += fs16_to_cpu(sb, de->d_reclen);
169 }
170 offset = 0;
171 brelse (bh);
172 }
173 unlock_kernel();
174 return 0;
175 }
176
177 /*
178 * define how far ahead to read directories while searching them.
179 */
180 #define NAMEI_RA_CHUNKS 2
181 #define NAMEI_RA_BLOCKS 4
182 #define NAMEI_RA_SIZE (NAMEI_RA_CHUNKS * NAMEI_RA_BLOCKS)
183 #define NAMEI_RA_INDEX(c,b) (((c) * NAMEI_RA_BLOCKS) + (b))
184
185 /*
186 * ufs_find_entry()
187 *
188 * finds an entry in the specified directory with the wanted name. It
189 * returns the cache buffer in which the entry was found, and the entry
190 * itself (as a parameter - res_bh). It does NOT read the inode of the
191 * entry - you'll have to do that yourself if you want to.
192 */
193 struct ufs_dir_entry * ufs_find_entry (struct dentry *dentry,
194 struct buffer_head ** res_bh)
195 {
196 struct super_block * sb;
197 struct buffer_head * bh_use[NAMEI_RA_SIZE];
198 struct buffer_head * bh_read[NAMEI_RA_SIZE];
199 unsigned long offset;
200 int block, toread, i, err;
201 struct inode *dir = dentry->d_parent->d_inode;
202 const char *name = dentry->d_name.name;
203 int namelen = dentry->d_name.len;
204
205 UFSD(("ENTER, dir_ino %lu, name %s, namlen %u\n", dir->i_ino, name, namelen))
206
207 *res_bh = NULL;
208
209 sb = dir->i_sb;
210
211 if (namelen > UFS_MAXNAMLEN)
212 return NULL;
213
214 memset (bh_use, 0, sizeof (bh_use));
215 toread = 0;
216 for (block = 0; block < NAMEI_RA_SIZE; ++block) {
217 struct buffer_head * bh;
218
219 if ((block << sb->s_blocksize_bits) >= dir->i_size)
220 break;
221 bh = ufs_getfrag (dir, block, 0, &err);
222 bh_use[block] = bh;
223 if (bh && !buffer_uptodate(bh))
224 bh_read[toread++] = bh;
225 }
226
227 for (block = 0, offset = 0; offset < dir->i_size; block++) {
228 struct buffer_head * bh;
229 struct ufs_dir_entry * de;
230 char * dlimit;
231
232 if ((block % NAMEI_RA_BLOCKS) == 0 && toread) {
233 ll_rw_block (READ, toread, bh_read);
234 toread = 0;
235 }
236 bh = bh_use[block % NAMEI_RA_SIZE];
237 if (!bh) {
238 ufs_error (sb, "ufs_find_entry",
239 "directory #%lu contains a hole at offset %lu",
240 dir->i_ino, offset);
241 offset += sb->s_blocksize;
242 continue;
243 }
244 wait_on_buffer (bh);
245 if (!buffer_uptodate(bh)) {
246 /*
247 * read error: all bets are off
248 */
249 break;
250 }
251
252 de = (struct ufs_dir_entry *) bh->b_data;
253 dlimit = bh->b_data + sb->s_blocksize;
254 while ((char *) de < dlimit && offset < dir->i_size) {
255 /* this code is executed quadratically often */
256 /* do minimal checking by hand */
257 int de_len;
258
259 if ((char *) de + namelen <= dlimit &&
260 ufs_match(sb, namelen, name, de)) {
261 /* found a match -
262 just to be sure, do a full check */
263 if (!ufs_check_dir_entry("ufs_find_entry",
264 dir, de, bh, offset))
265 goto failed;
266 for (i = 0; i < NAMEI_RA_SIZE; ++i) {
267 if (bh_use[i] != bh)
268 brelse (bh_use[i]);
269 }
270 *res_bh = bh;
271 return de;
272 }
273 /* prevent looping on a bad block */
274 de_len = fs16_to_cpu(sb, de->d_reclen);
275 if (de_len <= 0)
276 goto failed;
277 offset += de_len;
278 de = (struct ufs_dir_entry *) ((char *) de + de_len);
279 }
280
281 brelse (bh);
282 if (((block + NAMEI_RA_SIZE) << sb->s_blocksize_bits ) >=
283 dir->i_size)
284 bh = NULL;
285 else
286 bh = ufs_getfrag (dir, block + NAMEI_RA_SIZE, 0, &err);
287 bh_use[block % NAMEI_RA_SIZE] = bh;
288 if (bh && !buffer_uptodate(bh))
289 bh_read[toread++] = bh;
290 }
291
292 failed:
293 for (i = 0; i < NAMEI_RA_SIZE; ++i) brelse (bh_use[i]);
294 UFSD(("EXIT\n"))
295 return NULL;
296 }
297
298 static int
299 ufs_check_dir_entry (const char *function, struct inode *dir,
300 struct ufs_dir_entry *de, struct buffer_head *bh,
301 unsigned long offset)
302 {
303 struct super_block *sb = dir->i_sb;
304 const char *error_msg = NULL;
305 int rlen = fs16_to_cpu(sb, de->d_reclen);
306
307 if (rlen < UFS_DIR_REC_LEN(1))
308 error_msg = "reclen is smaller than minimal";
309 else if (rlen % 4 != 0)
310 error_msg = "reclen % 4 != 0";
311 else if (rlen < UFS_DIR_REC_LEN(ufs_get_de_namlen(sb, de)))
312 error_msg = "reclen is too small for namlen";
313 else if (((char *) de - bh->b_data) + rlen > dir->i_sb->s_blocksize)
314 error_msg = "directory entry across blocks";
315 else if (fs32_to_cpu(sb, de->d_ino) > (UFS_SB(sb)->s_uspi->s_ipg *
316 UFS_SB(sb)->s_uspi->s_ncg))
317 error_msg = "inode out of bounds";
318
319 if (error_msg != NULL)
320 ufs_error (sb, function, "bad entry in directory #%lu, size %Lu: %s - "
321 "offset=%lu, inode=%lu, reclen=%d, namlen=%d",
322 dir->i_ino, dir->i_size, error_msg, offset,
323 (unsigned long)fs32_to_cpu(sb, de->d_ino),
324 rlen, ufs_get_de_namlen(sb, de));
325
326 return (error_msg == NULL ? 1 : 0);
327 }
328
329 struct ufs_dir_entry *ufs_dotdot(struct inode *dir, struct buffer_head **p)
330 {
331 int err;
332 struct buffer_head *bh = ufs_bread (dir, 0, 0, &err);
333 struct ufs_dir_entry *res = NULL;
334
335 if (bh) {
336 res = (struct ufs_dir_entry *) bh->b_data;
337 res = (struct ufs_dir_entry *)((char *)res +
338 fs16_to_cpu(dir->i_sb, res->d_reclen));
339 }
340 *p = bh;
341 return res;
342 }
343 ino_t ufs_inode_by_name(struct inode * dir, struct dentry *dentry)
344 {
345 ino_t res = 0;
346 struct ufs_dir_entry * de;
347 struct buffer_head *bh;
348
349 de = ufs_find_entry (dentry, &bh);
350 if (de) {
351 res = fs32_to_cpu(dir->i_sb, de->d_ino);
352 brelse(bh);
353 }
354 return res;
355 }
356
357 void ufs_set_link(struct inode *dir, struct ufs_dir_entry *de,
358 struct buffer_head *bh, struct inode *inode)
359 {
360 dir->i_version++;
361 de->d_ino = cpu_to_fs32(dir->i_sb, inode->i_ino);
362 mark_buffer_dirty(bh);
363 if (IS_DIRSYNC(dir))
364 sync_dirty_buffer(bh);
365 brelse (bh);
366 }
367
368 /*
369 * ufs_add_entry()
370 *
371 * adds a file entry to the specified directory, using the same
372 * semantics as ufs_find_entry(). It returns NULL if it failed.
373 */
374 int ufs_add_link(struct dentry *dentry, struct inode *inode)
375 {
376 struct super_block * sb;
377 struct ufs_sb_private_info * uspi;
378 unsigned long offset;
379 unsigned fragoff;
380 unsigned short rec_len;
381 struct buffer_head * bh;
382 struct ufs_dir_entry * de, * de1;
383 struct inode *dir = dentry->d_parent->d_inode;
384 const char *name = dentry->d_name.name;
385 int namelen = dentry->d_name.len;
386 int err;
387
388 UFSD(("ENTER, name %s, namelen %u\n", name, namelen))
389
390 sb = dir->i_sb;
391 uspi = UFS_SB(sb)->s_uspi;
392
393 if (!namelen)
394 return -EINVAL;
395 bh = ufs_bread (dir, 0, 0, &err);
396 if (!bh)
397 return err;
398 rec_len = UFS_DIR_REC_LEN(namelen);
399 offset = 0;
400 de = (struct ufs_dir_entry *) bh->b_data;
401 while (1) {
402 if ((char *)de >= UFS_SECTOR_SIZE + bh->b_data) {
403 fragoff = offset & ~uspi->s_fmask;
404 if (fragoff != 0 && fragoff != UFS_SECTOR_SIZE)
405 ufs_error (sb, "ufs_add_entry", "internal error"
406 " fragoff %u", fragoff);
407 if (!fragoff) {
408 brelse (bh);
409 bh = ufs_bread (dir, offset >> sb->s_blocksize_bits, 1, &err);
410 if (!bh)
411 return err;
412 }
413 if (dir->i_size <= offset) {
414 if (dir->i_size == 0) {
415 brelse(bh);
416 return -ENOENT;
417 }
418 de = (struct ufs_dir_entry *) (bh->b_data + fragoff);
419 de->d_ino = 0;
420 de->d_reclen = cpu_to_fs16(sb, UFS_SECTOR_SIZE);
421 ufs_set_de_namlen(sb, de, 0);
422 dir->i_size = offset + UFS_SECTOR_SIZE;
423 mark_inode_dirty(dir);
424 } else {
425 de = (struct ufs_dir_entry *) bh->b_data;
426 }
427 }
428 if (!ufs_check_dir_entry ("ufs_add_entry", dir, de, bh, offset)) {
429 brelse (bh);
430 return -ENOENT;
431 }
432 if (ufs_match(sb, namelen, name, de)) {
433 brelse (bh);
434 return -EEXIST;
435 }
436 if (de->d_ino == 0 && fs16_to_cpu(sb, de->d_reclen) >= rec_len)
437 break;
438
439 if (fs16_to_cpu(sb, de->d_reclen) >=
440 UFS_DIR_REC_LEN(ufs_get_de_namlen(sb, de)) + rec_len)
441 break;
442 offset += fs16_to_cpu(sb, de->d_reclen);
443 de = (struct ufs_dir_entry *) ((char *) de + fs16_to_cpu(sb, de->d_reclen));
444 }
445
446 if (de->d_ino) {
447 de1 = (struct ufs_dir_entry *) ((char *) de +
448 UFS_DIR_REC_LEN(ufs_get_de_namlen(sb, de)));
449 de1->d_reclen =
450 cpu_to_fs16(sb, fs16_to_cpu(sb, de->d_reclen) -
451 UFS_DIR_REC_LEN(ufs_get_de_namlen(sb, de)));
452 de->d_reclen =
453 cpu_to_fs16(sb, UFS_DIR_REC_LEN(ufs_get_de_namlen(sb, de)));
454 de = de1;
455 }
456 de->d_ino = 0;
457 ufs_set_de_namlen(sb, de, namelen);
458 memcpy (de->d_name, name, namelen + 1);
459 de->d_ino = cpu_to_fs32(sb, inode->i_ino);
460 ufs_set_de_type(sb, de, inode->i_mode);
461 mark_buffer_dirty(bh);
462 if (IS_DIRSYNC(dir))
463 sync_dirty_buffer(bh);
464 brelse (bh);
465 dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
466 dir->i_version++;
467 mark_inode_dirty(dir);
468
469 UFSD(("EXIT\n"))
470 return 0;
471 }
472
473 /*
474 * ufs_delete_entry deletes a directory entry by merging it with the
475 * previous entry.
476 */
477 int ufs_delete_entry (struct inode * inode, struct ufs_dir_entry * dir,
478 struct buffer_head * bh )
479
480 {
481 struct super_block * sb;
482 struct ufs_dir_entry * de, * pde;
483 unsigned i;
484
485 UFSD(("ENTER\n"))
486
487 sb = inode->i_sb;
488 i = 0;
489 pde = NULL;
490 de = (struct ufs_dir_entry *) bh->b_data;
491
492 UFSD(("ino %u, reclen %u, namlen %u, name %s\n",
493 fs32_to_cpu(sb, de->d_ino),
494 fs16to_cpu(sb, de->d_reclen),
495 ufs_get_de_namlen(sb, de), de->d_name))
496
497 while (i < bh->b_size) {
498 if (!ufs_check_dir_entry ("ufs_delete_entry", inode, de, bh, i)) {
499 brelse(bh);
500 return -EIO;
501 }
502 if (de == dir) {
503 if (pde)
504 fs16_add(sb, &pde->d_reclen,
505 fs16_to_cpu(sb, dir->d_reclen));
506 dir->d_ino = 0;
507 inode->i_version++;
508 inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
509 mark_inode_dirty(inode);
510 mark_buffer_dirty(bh);
511 if (IS_DIRSYNC(inode))
512 sync_dirty_buffer(bh);
513 brelse(bh);
514 UFSD(("EXIT\n"))
515 return 0;
516 }
517 i += fs16_to_cpu(sb, de->d_reclen);
518 if (i == UFS_SECTOR_SIZE) pde = NULL;
519 else pde = de;
520 de = (struct ufs_dir_entry *)
521 ((char *) de + fs16_to_cpu(sb, de->d_reclen));
522 if (i == UFS_SECTOR_SIZE && de->d_reclen == 0)
523 break;
524 }
525 UFSD(("EXIT\n"))
526 brelse(bh);
527 return -ENOENT;
528 }
529
530 int ufs_make_empty(struct inode * inode, struct inode *dir)
531 {
532 struct super_block * sb = dir->i_sb;
533 struct buffer_head * dir_block;
534 struct ufs_dir_entry * de;
535 int err;
536
537 dir_block = ufs_bread (inode, 0, 1, &err);
538 if (!dir_block)
539 return err;
540
541 inode->i_blocks = sb->s_blocksize / UFS_SECTOR_SIZE;
542 de = (struct ufs_dir_entry *) dir_block->b_data;
543 de->d_ino = cpu_to_fs32(sb, inode->i_ino);
544 ufs_set_de_type(sb, de, inode->i_mode);
545 ufs_set_de_namlen(sb, de, 1);
546 de->d_reclen = cpu_to_fs16(sb, UFS_DIR_REC_LEN(1));
547 strcpy (de->d_name, ".");
548 de = (struct ufs_dir_entry *)
549 ((char *)de + fs16_to_cpu(sb, de->d_reclen));
550 de->d_ino = cpu_to_fs32(sb, dir->i_ino);
551 ufs_set_de_type(sb, de, dir->i_mode);
552 de->d_reclen = cpu_to_fs16(sb, UFS_SECTOR_SIZE - UFS_DIR_REC_LEN(1));
553 ufs_set_de_namlen(sb, de, 2);
554 strcpy (de->d_name, "..");
555 mark_buffer_dirty(dir_block);
556 brelse (dir_block);
557 mark_inode_dirty(inode);
558 return 0;
559 }
560
561 /*
562 * routine to check that the specified directory is empty (for rmdir)
563 */
564 int ufs_empty_dir (struct inode * inode)
565 {
566 struct super_block * sb;
567 unsigned long offset;
568 struct buffer_head * bh;
569 struct ufs_dir_entry * de, * de1;
570 int err;
571
572 sb = inode->i_sb;
573
574 if (inode->i_size < UFS_DIR_REC_LEN(1) + UFS_DIR_REC_LEN(2) ||
575 !(bh = ufs_bread (inode, 0, 0, &err))) {
576 ufs_warning (inode->i_sb, "empty_dir",
577 "bad directory (dir #%lu) - no data block",
578 inode->i_ino);
579 return 1;
580 }
581 de = (struct ufs_dir_entry *) bh->b_data;
582 de1 = (struct ufs_dir_entry *)
583 ((char *)de + fs16_to_cpu(sb, de->d_reclen));
584 if (fs32_to_cpu(sb, de->d_ino) != inode->i_ino || de1->d_ino == 0 ||
585 strcmp (".", de->d_name) || strcmp ("..", de1->d_name)) {
586 ufs_warning (inode->i_sb, "empty_dir",
587 "bad directory (dir #%lu) - no `.' or `..'",
588 inode->i_ino);
589 return 1;
590 }
591 offset = fs16_to_cpu(sb, de->d_reclen) + fs16_to_cpu(sb, de1->d_reclen);
592 de = (struct ufs_dir_entry *)
593 ((char *)de1 + fs16_to_cpu(sb, de1->d_reclen));
594 while (offset < inode->i_size ) {
595 if (!bh || (void *) de >= (void *) (bh->b_data + sb->s_blocksize)) {
596 brelse (bh);
597 bh = ufs_bread (inode, offset >> sb->s_blocksize_bits, 1, &err);
598 if (!bh) {
599 ufs_error (sb, "empty_dir",
600 "directory #%lu contains a hole at offset %lu",
601 inode->i_ino, offset);
602 offset += sb->s_blocksize;
603 continue;
604 }
605 de = (struct ufs_dir_entry *) bh->b_data;
606 }
607 if (!ufs_check_dir_entry ("empty_dir", inode, de, bh, offset)) {
608 brelse (bh);
609 return 1;
610 }
611 if (de->d_ino) {
612 brelse (bh);
613 return 0;
614 }
615 offset += fs16_to_cpu(sb, de->d_reclen);
616 de = (struct ufs_dir_entry *)
617 ((char *)de + fs16_to_cpu(sb, de->d_reclen));
618 }
619 brelse (bh);
620 return 1;
621 }
622
623 struct file_operations ufs_dir_operations = {
624 .read = generic_read_dir,
625 .readdir = ufs_readdir,
626 .fsync = file_fsync,
627 };