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[PATCH] Add a driver for the Technisat Skystar2 DVB card
[linux-2.6/history.git] / fs / ufs / dir.c
blob463c4bca0b621ad4b3aeb2085299fec0e46e77bc
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
35
36 /*
37 * NOTE! unlike strncmp, ufs_match returns 1 for success, 0 for failure.
38 *
39 * len <= UFS_MAXNAMLEN and de != NULL are guaranteed by caller.
40 */
41 static inline int ufs_match(struct super_block *sb, int len,
42 const char * const name, struct ufs_dir_entry * de)
43 {
44 if (len != ufs_get_de_namlen(sb, de))
45 return 0;
46 if (!de->d_ino)
47 return 0;
48 return !memcmp(name, de->d_name, len);
49 }
50
51 /*
52 * This is blatantly stolen from ext2fs
53 */
54 static int
55 ufs_readdir (struct file * filp, void * dirent, filldir_t filldir)
56 {
57 struct inode *inode = filp->f_dentry->d_inode;
58 int error = 0;
59 unsigned long offset, lblk, blk;
60 int i, stored;
61 struct buffer_head * bh;
62 struct ufs_dir_entry * de;
63 struct super_block * sb;
64 int de_reclen;
65 unsigned flags;
66
67 lock_kernel();
68
69 sb = inode->i_sb;
70 flags = UFS_SB(sb)->s_flags;
71
72 UFSD(("ENTER, ino %lu f_pos %lu\n", inode->i_ino, (unsigned long) filp->f_pos))
73
74 stored = 0;
75 bh = NULL;
76 offset = filp->f_pos & (sb->s_blocksize - 1);
77
78 while (!error && !stored && filp->f_pos < inode->i_size) {
79 lblk = (filp->f_pos) >> sb->s_blocksize_bits;
80 blk = ufs_frag_map(inode, lblk);
81 if (!blk || !(bh = sb_bread(sb, blk))) {
82 /* XXX - error - skip to the next block */
83 printk("ufs_readdir: "
84 "dir inode %lu has a hole at offset %lu\n",
85 inode->i_ino, (unsigned long int)filp->f_pos);
86 filp->f_pos += sb->s_blocksize - offset;
87 continue;
88 }
89
90 revalidate:
91 /* If the dir block has changed since the last call to
92 * readdir(2), then we might be pointing to an invalid
93 * dirent right now. Scan from the start of the block
94 * to make sure. */
95 if (filp->f_version != inode->i_version) {
96 for (i = 0; i < sb->s_blocksize && i < offset; ) {
97 de = (struct ufs_dir_entry *)(bh->b_data + i);
98 /* It's too expensive to do a full
99 * dirent test each time round this
100 * loop, but we do have to test at
101 * least that it is non-zero. A
102 * failure will be detected in the
103 * dirent test below. */
104 de_reclen = fs16_to_cpu(sb, de->d_reclen);
105 if (de_reclen < 1)
106 break;
107 i += de_reclen;
108 }
109 offset = i;
110 filp->f_pos = (filp->f_pos & ~(sb->s_blocksize - 1))
111 | offset;
112 filp->f_version = inode->i_version;
113 }
114
115 while (!error && filp->f_pos < inode->i_size
116 && offset < sb->s_blocksize) {
117 de = (struct ufs_dir_entry *) (bh->b_data + offset);
118 /* XXX - put in a real ufs_check_dir_entry() */
119 if ((de->d_reclen == 0) || (ufs_get_de_namlen(sb, de) == 0)) {
120 filp->f_pos = (filp->f_pos &
121 (sb->s_blocksize - 1)) +
122 sb->s_blocksize;
123 brelse(bh);
124 unlock_kernel();
125 return stored;
126 }
127 if (!ufs_check_dir_entry ("ufs_readdir", inode, de,
128 bh, offset)) {
129 /* On error, skip the f_pos to the
130 next block. */
131 filp->f_pos = (filp->f_pos |
132 (sb->s_blocksize - 1)) +
133 1;
134 brelse (bh);
135 unlock_kernel();
136 return stored;
137 }
138 offset += fs16_to_cpu(sb, de->d_reclen);
139 if (de->d_ino) {
140 /* We might block in the next section
141 * if the data destination is
142 * currently swapped out. So, use a
143 * version stamp to detect whether or
144 * not the directory has been modified
145 * during the copy operation. */
146 unsigned long version = filp->f_version;
147 unsigned char d_type = DT_UNKNOWN;
148
149 UFSD(("filldir(%s,%u)\n", de->d_name,
150 fs32_to_cpu(sb, de->d_ino)))
151 UFSD(("namlen %u\n", ufs_get_de_namlen(sb, de)))
152
153 if ((flags & UFS_DE_MASK) == UFS_DE_44BSD)
154 d_type = de->d_u.d_44.d_type;
155 error = filldir(dirent, de->d_name,
156 ufs_get_de_namlen(sb, de), filp->f_pos,
157 fs32_to_cpu(sb, de->d_ino), d_type);
158 if (error)
159 break;
160 if (version != filp->f_version)
161 goto revalidate;
162 stored ++;
163 }
164 filp->f_pos += fs16_to_cpu(sb, de->d_reclen);
165 }
166 offset = 0;
167 brelse (bh);
168 }
169 update_atime(inode);
170 unlock_kernel();
171 return 0;
172 }
173
174 /*
175 * define how far ahead to read directories while searching them.
176 */
177 #define NAMEI_RA_CHUNKS 2
178 #define NAMEI_RA_BLOCKS 4
179 #define NAMEI_RA_SIZE (NAMEI_RA_CHUNKS * NAMEI_RA_BLOCKS)
180 #define NAMEI_RA_INDEX(c,b) (((c) * NAMEI_RA_BLOCKS) + (b))
181
182 /*
183 * ufs_find_entry()
184 *
185 * finds an entry in the specified directory with the wanted name. It
186 * returns the cache buffer in which the entry was found, and the entry
187 * itself (as a parameter - res_bh). It does NOT read the inode of the
188 * entry - you'll have to do that yourself if you want to.
189 */
190 struct ufs_dir_entry * ufs_find_entry (struct dentry *dentry,
191 struct buffer_head ** res_bh)
192 {
193 struct super_block * sb;
194 struct buffer_head * bh_use[NAMEI_RA_SIZE];
195 struct buffer_head * bh_read[NAMEI_RA_SIZE];
196 unsigned long offset;
197 int block, toread, i, err;
198 struct inode *dir = dentry->d_parent->d_inode;
199 const char *name = dentry->d_name.name;
200 int namelen = dentry->d_name.len;
201
202 UFSD(("ENTER, dir_ino %lu, name %s, namlen %u\n", dir->i_ino, name, namelen))
203
204 *res_bh = NULL;
205
206 sb = dir->i_sb;
207
208 if (namelen > UFS_MAXNAMLEN)
209 return NULL;
210
211 memset (bh_use, 0, sizeof (bh_use));
212 toread = 0;
213 for (block = 0; block < NAMEI_RA_SIZE; ++block) {
214 struct buffer_head * bh;
215
216 if ((block << sb->s_blocksize_bits) >= dir->i_size)
217 break;
218 bh = ufs_getfrag (dir, block, 0, &err);
219 bh_use[block] = bh;
220 if (bh && !buffer_uptodate(bh))
221 bh_read[toread++] = bh;
222 }
223
224 for (block = 0, offset = 0; offset < dir->i_size; block++) {
225 struct buffer_head * bh;
226 struct ufs_dir_entry * de;
227 char * dlimit;
228
229 if ((block % NAMEI_RA_BLOCKS) == 0 && toread) {
230 ll_rw_block (READ, toread, bh_read);
231 toread = 0;
232 }
233 bh = bh_use[block % NAMEI_RA_SIZE];
234 if (!bh) {
235 ufs_error (sb, "ufs_find_entry",
236 "directory #%lu contains a hole at offset %lu",
237 dir->i_ino, offset);
238 offset += sb->s_blocksize;
239 continue;
240 }
241 wait_on_buffer (bh);
242 if (!buffer_uptodate(bh)) {
243 /*
244 * read error: all bets are off
245 */
246 break;
247 }
248
249 de = (struct ufs_dir_entry *) bh->b_data;
250 dlimit = bh->b_data + sb->s_blocksize;
251 while ((char *) de < dlimit && offset < dir->i_size) {
252 /* this code is executed quadratically often */
253 /* do minimal checking by hand */
254 int de_len;
255
256 if ((char *) de + namelen <= dlimit &&
257 ufs_match(sb, namelen, name, de)) {
258 /* found a match -
259 just to be sure, do a full check */
260 if (!ufs_check_dir_entry("ufs_find_entry",
261 dir, de, bh, offset))
262 goto failed;
263 for (i = 0; i < NAMEI_RA_SIZE; ++i) {
264 if (bh_use[i] != bh)
265 brelse (bh_use[i]);
266 }
267 *res_bh = bh;
268 return de;
269 }
270 /* prevent looping on a bad block */
271 de_len = fs16_to_cpu(sb, de->d_reclen);
272 if (de_len <= 0)
273 goto failed;
274 offset += de_len;
275 de = (struct ufs_dir_entry *) ((char *) de + de_len);
276 }
277
278 brelse (bh);
279 if (((block + NAMEI_RA_SIZE) << sb->s_blocksize_bits ) >=
280 dir->i_size)
281 bh = NULL;
282 else
283 bh = ufs_getfrag (dir, block + NAMEI_RA_SIZE, 0, &err);
284 bh_use[block % NAMEI_RA_SIZE] = bh;
285 if (bh && !buffer_uptodate(bh))
286 bh_read[toread++] = bh;
287 }
288
289 failed:
290 for (i = 0; i < NAMEI_RA_SIZE; ++i) brelse (bh_use[i]);
291 UFSD(("EXIT\n"))
292 return NULL;
293 }
294
295 int ufs_check_dir_entry (const char * function, struct inode * dir,
296 struct ufs_dir_entry * de, struct buffer_head * bh,
297 unsigned long offset)
298 {
299 struct super_block *sb = dir->i_sb;
300 const char *error_msg = NULL;
301 int rlen = fs16_to_cpu(sb, de->d_reclen);
302
303 if (rlen < UFS_DIR_REC_LEN(1))
304 error_msg = "reclen is smaller than minimal";
305 else if (rlen % 4 != 0)
306 error_msg = "reclen % 4 != 0";
307 else if (rlen < UFS_DIR_REC_LEN(ufs_get_de_namlen(sb, de)))
308 error_msg = "reclen is too small for namlen";
309 else if (((char *) de - bh->b_data) + rlen > dir->i_sb->s_blocksize)
310 error_msg = "directory entry across blocks";
311 else if (fs32_to_cpu(sb, de->d_ino) > (UFS_SB(sb)->s_uspi->s_ipg *
312 UFS_SB(sb)->s_uspi->s_ncg))
313 error_msg = "inode out of bounds";
314
315 if (error_msg != NULL)
316 ufs_error (sb, function, "bad entry in directory #%lu, size %Lu: %s - "
317 "offset=%lu, inode=%lu, reclen=%d, namlen=%d",
318 dir->i_ino, dir->i_size, error_msg, offset,
319 (unsigned long)fs32_to_cpu(sb, de->d_ino),
320 rlen, ufs_get_de_namlen(sb, de));
321
322 return (error_msg == NULL ? 1 : 0);
323 }
324
325 struct ufs_dir_entry *ufs_dotdot(struct inode *dir, struct buffer_head **p)
326 {
327 int err;
328 struct buffer_head *bh = ufs_bread (dir, 0, 0, &err);
329 struct ufs_dir_entry *res = NULL;
330
331 if (bh) {
332 res = (struct ufs_dir_entry *) bh->b_data;
333 res = (struct ufs_dir_entry *)((char *)res +
334 fs16_to_cpu(dir->i_sb, res->d_reclen));
335 }
336 *p = bh;
337 return res;
338 }
339 ino_t ufs_inode_by_name(struct inode * dir, struct dentry *dentry)
340 {
341 ino_t res = 0;
342 struct ufs_dir_entry * de;
343 struct buffer_head *bh;
344
345 de = ufs_find_entry (dentry, &bh);
346 if (de) {
347 res = fs32_to_cpu(dir->i_sb, de->d_ino);
348 brelse(bh);
349 }
350 return res;
351 }
352
353 void ufs_set_link(struct inode *dir, struct ufs_dir_entry *de,
354 struct buffer_head *bh, struct inode *inode)
355 {
356 dir->i_version++;
357 de->d_ino = cpu_to_fs32(dir->i_sb, inode->i_ino);
358 mark_buffer_dirty(bh);
359 if (IS_DIRSYNC(dir))
360 sync_dirty_buffer(bh);
361 brelse (bh);
362 }
363
364 /*
365 * ufs_add_entry()
366 *
367 * adds a file entry to the specified directory, using the same
368 * semantics as ufs_find_entry(). It returns NULL if it failed.
369 */
370 int ufs_add_link(struct dentry *dentry, struct inode *inode)
371 {
372 struct super_block * sb;
373 struct ufs_sb_private_info * uspi;
374 unsigned long offset;
375 unsigned fragoff;
376 unsigned short rec_len;
377 struct buffer_head * bh;
378 struct ufs_dir_entry * de, * de1;
379 struct inode *dir = dentry->d_parent->d_inode;
380 const char *name = dentry->d_name.name;
381 int namelen = dentry->d_name.len;
382 int err;
383
384 UFSD(("ENTER, name %s, namelen %u\n", name, namelen))
385
386 sb = dir->i_sb;
387 uspi = UFS_SB(sb)->s_uspi;
388
389 if (!namelen)
390 return -EINVAL;
391 bh = ufs_bread (dir, 0, 0, &err);
392 if (!bh)
393 return err;
394 rec_len = UFS_DIR_REC_LEN(namelen);
395 offset = 0;
396 de = (struct ufs_dir_entry *) bh->b_data;
397 while (1) {
398 if ((char *)de >= UFS_SECTOR_SIZE + bh->b_data) {
399 fragoff = offset & ~uspi->s_fmask;
400 if (fragoff != 0 && fragoff != UFS_SECTOR_SIZE)
401 ufs_error (sb, "ufs_add_entry", "internal error"
402 " fragoff %u", fragoff);
403 if (!fragoff) {
404 brelse (bh);
405 bh = ufs_bread (dir, offset >> sb->s_blocksize_bits, 1, &err);
406 if (!bh)
407 return err;
408 }
409 if (dir->i_size <= offset) {
410 if (dir->i_size == 0) {
411 brelse(bh);
412 return -ENOENT;
413 }
414 de = (struct ufs_dir_entry *) (bh->b_data + fragoff);
415 de->d_ino = 0;
416 de->d_reclen = cpu_to_fs16(sb, UFS_SECTOR_SIZE);
417 ufs_set_de_namlen(sb, de, 0);
418 dir->i_size = offset + UFS_SECTOR_SIZE;
419 mark_inode_dirty(dir);
420 } else {
421 de = (struct ufs_dir_entry *) bh->b_data;
422 }
423 }
424 if (!ufs_check_dir_entry ("ufs_add_entry", dir, de, bh, offset)) {
425 brelse (bh);
426 return -ENOENT;
427 }
428 if (ufs_match(sb, namelen, name, de)) {
429 brelse (bh);
430 return -EEXIST;
431 }
432 if (de->d_ino == 0 && fs16_to_cpu(sb, de->d_reclen) >= rec_len)
433 break;
434
435 if (fs16_to_cpu(sb, de->d_reclen) >=
436 UFS_DIR_REC_LEN(ufs_get_de_namlen(sb, de)) + rec_len)
437 break;
438 offset += fs16_to_cpu(sb, de->d_reclen);
439 de = (struct ufs_dir_entry *) ((char *) de + fs16_to_cpu(sb, de->d_reclen));
440 }
441
442 if (de->d_ino) {
443 de1 = (struct ufs_dir_entry *) ((char *) de +
444 UFS_DIR_REC_LEN(ufs_get_de_namlen(sb, de)));
445 de1->d_reclen =
446 cpu_to_fs16(sb, fs16_to_cpu(sb, de->d_reclen) -
447 UFS_DIR_REC_LEN(ufs_get_de_namlen(sb, de)));
448 de->d_reclen =
449 cpu_to_fs16(sb, UFS_DIR_REC_LEN(ufs_get_de_namlen(sb, de)));
450 de = de1;
451 }
452 de->d_ino = 0;
453 ufs_set_de_namlen(sb, de, namelen);
454 memcpy (de->d_name, name, namelen + 1);
455 de->d_ino = cpu_to_fs32(sb, inode->i_ino);
456 ufs_set_de_type(sb, de, inode->i_mode);
457 mark_buffer_dirty(bh);
458 if (IS_DIRSYNC(dir))
459 sync_dirty_buffer(bh);
460 brelse (bh);
461 dir->i_mtime = dir->i_ctime = CURRENT_TIME;
462 dir->i_version++;
463 mark_inode_dirty(dir);
464
465 UFSD(("EXIT\n"))
466 return 0;
467 }
468
469 /*
470 * ufs_delete_entry deletes a directory entry by merging it with the
471 * previous entry.
472 */
473 int ufs_delete_entry (struct inode * inode, struct ufs_dir_entry * dir,
474 struct buffer_head * bh )
475
476 {
477 struct super_block * sb;
478 struct ufs_dir_entry * de, * pde;
479 unsigned i;
480
481 UFSD(("ENTER\n"))
482
483 sb = inode->i_sb;
484 i = 0;
485 pde = NULL;
486 de = (struct ufs_dir_entry *) bh->b_data;
487
488 UFSD(("ino %u, reclen %u, namlen %u, name %s\n",
489 fs32_to_cpu(sb, de->d_ino),
490 fs16to_cpu(sb, de->d_reclen),
491 ufs_get_de_namlen(sb, de), de->d_name))
492
493 while (i < bh->b_size) {
494 if (!ufs_check_dir_entry ("ufs_delete_entry", inode, de, bh, i)) {
495 brelse(bh);
496 return -EIO;
497 }
498 if (de == dir) {
499 if (pde)
500 fs16_add(sb, &pde->d_reclen,
501 fs16_to_cpu(sb, dir->d_reclen));
502 dir->d_ino = 0;
503 inode->i_version++;
504 inode->i_ctime = inode->i_mtime = CURRENT_TIME;
505 mark_inode_dirty(inode);
506 mark_buffer_dirty(bh);
507 if (IS_DIRSYNC(inode))
508 sync_dirty_buffer(bh);
509 brelse(bh);
510 UFSD(("EXIT\n"))
511 return 0;
512 }
513 i += fs16_to_cpu(sb, de->d_reclen);
514 if (i == UFS_SECTOR_SIZE) pde = NULL;
515 else pde = de;
516 de = (struct ufs_dir_entry *)
517 ((char *) de + fs16_to_cpu(sb, de->d_reclen));
518 if (i == UFS_SECTOR_SIZE && de->d_reclen == 0)
519 break;
520 }
521 UFSD(("EXIT\n"))
522 brelse(bh);
523 return -ENOENT;
524 }
525
526 int ufs_make_empty(struct inode * inode, struct inode *dir)
527 {
528 struct super_block * sb = dir->i_sb;
529 struct buffer_head * dir_block;
530 struct ufs_dir_entry * de;
531 int err;
532
533 dir_block = ufs_bread (inode, 0, 1, &err);
534 if (!dir_block)
535 return err;
536
537 inode->i_blocks = sb->s_blocksize / UFS_SECTOR_SIZE;
538 de = (struct ufs_dir_entry *) dir_block->b_data;
539 de->d_ino = cpu_to_fs32(sb, inode->i_ino);
540 ufs_set_de_type(sb, de, inode->i_mode);
541 ufs_set_de_namlen(sb, de, 1);
542 de->d_reclen = cpu_to_fs16(sb, UFS_DIR_REC_LEN(1));
543 strcpy (de->d_name, ".");
544 de = (struct ufs_dir_entry *)
545 ((char *)de + fs16_to_cpu(sb, de->d_reclen));
546 de->d_ino = cpu_to_fs32(sb, dir->i_ino);
547 ufs_set_de_type(sb, de, dir->i_mode);
548 de->d_reclen = cpu_to_fs16(sb, UFS_SECTOR_SIZE - UFS_DIR_REC_LEN(1));
549 ufs_set_de_namlen(sb, de, 2);
550 strcpy (de->d_name, "..");
551 mark_buffer_dirty(dir_block);
552 brelse (dir_block);
553 mark_inode_dirty(inode);
554 return 0;
555 }
556
557 /*
558 * routine to check that the specified directory is empty (for rmdir)
559 */
560 int ufs_empty_dir (struct inode * inode)
561 {
562 struct super_block * sb;
563 unsigned long offset;
564 struct buffer_head * bh;
565 struct ufs_dir_entry * de, * de1;
566 int err;
567
568 sb = inode->i_sb;
569
570 if (inode->i_size < UFS_DIR_REC_LEN(1) + UFS_DIR_REC_LEN(2) ||
571 !(bh = ufs_bread (inode, 0, 0, &err))) {
572 ufs_warning (inode->i_sb, "empty_dir",
573 "bad directory (dir #%lu) - no data block",
574 inode->i_ino);
575 return 1;
576 }
577 de = (struct ufs_dir_entry *) bh->b_data;
578 de1 = (struct ufs_dir_entry *)
579 ((char *)de + fs16_to_cpu(sb, de->d_reclen));
580 if (fs32_to_cpu(sb, de->d_ino) != inode->i_ino || de1->d_ino == 0 ||
581 strcmp (".", de->d_name) || strcmp ("..", de1->d_name)) {
582 ufs_warning (inode->i_sb, "empty_dir",
583 "bad directory (dir #%lu) - no `.' or `..'",
584 inode->i_ino);
585 return 1;
586 }
587 offset = fs16_to_cpu(sb, de->d_reclen) + fs16_to_cpu(sb, de1->d_reclen);
588 de = (struct ufs_dir_entry *)
589 ((char *)de1 + fs16_to_cpu(sb, de1->d_reclen));
590 while (offset < inode->i_size ) {
591 if (!bh || (void *) de >= (void *) (bh->b_data + sb->s_blocksize)) {
592 brelse (bh);
593 bh = ufs_bread (inode, offset >> sb->s_blocksize_bits, 1, &err);
594 if (!bh) {
595 ufs_error (sb, "empty_dir",
596 "directory #%lu contains a hole at offset %lu",
597 inode->i_ino, offset);
598 offset += sb->s_blocksize;
599 continue;
600 }
601 de = (struct ufs_dir_entry *) bh->b_data;
602 }
603 if (!ufs_check_dir_entry ("empty_dir", inode, de, bh, offset)) {
604 brelse (bh);
605 return 1;
606 }
607 if (de->d_ino) {
608 brelse (bh);
609 return 0;
610 }
611 offset += fs16_to_cpu(sb, de->d_reclen);
612 de = (struct ufs_dir_entry *)
613 ((char *)de + fs16_to_cpu(sb, de->d_reclen));
614 }
615 brelse (bh);
616 return 1;
617 }
618
619 struct file_operations ufs_dir_operations = {
620 .read = generic_read_dir,
621 .readdir = ufs_readdir,
622 .fsync = file_fsync,
623 };
Historical 2.5/2.6 development