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Phonet: put protocols array under RCU
[linux/fpc-iii.git] / fs / coda / dir.c
blob4bb9d0a5decc2a7f168a1886a01ef72cec5a5351
1
2 /*
3 * Directory operations for Coda filesystem
4 * Original version: (C) 1996 P. Braam and M. Callahan
5 * Rewritten for Linux 2.1. (C) 1997 Carnegie Mellon University
6 *
7 * Carnegie Mellon encourages users to contribute improvements to
8 * the Coda project. Contact Peter Braam (coda@cs.cmu.edu).
9 */
10
11 #include <linux/types.h>
12 #include <linux/kernel.h>
13 #include <linux/time.h>
14 #include <linux/fs.h>
15 #include <linux/file.h>
16 #include <linux/stat.h>
17 #include <linux/errno.h>
18 #include <linux/string.h>
19 #include <linux/smp_lock.h>
20
21 #include <asm/uaccess.h>
22
23 #include <linux/coda.h>
24 #include <linux/coda_linux.h>
25 #include <linux/coda_psdev.h>
26 #include <linux/coda_fs_i.h>
27 #include <linux/coda_cache.h>
28
29 #include "coda_int.h"
30
31 /* dir inode-ops */
32 static int coda_create(struct inode *dir, struct dentry *new, int mode, struct nameidata *nd);
33 static struct dentry *coda_lookup(struct inode *dir, struct dentry *target, struct nameidata *nd);
34 static int coda_link(struct dentry *old_dentry, struct inode *dir_inode,
35 struct dentry *entry);
36 static int coda_unlink(struct inode *dir_inode, struct dentry *entry);
37 static int coda_symlink(struct inode *dir_inode, struct dentry *entry,
38 const char *symname);
39 static int coda_mkdir(struct inode *dir_inode, struct dentry *entry, int mode);
40 static int coda_rmdir(struct inode *dir_inode, struct dentry *entry);
41 static int coda_rename(struct inode *old_inode, struct dentry *old_dentry,
42 struct inode *new_inode, struct dentry *new_dentry);
43
44 /* dir file-ops */
45 static int coda_readdir(struct file *file, void *buf, filldir_t filldir);
46
47 /* dentry ops */
48 static int coda_dentry_revalidate(struct dentry *de, struct nameidata *nd);
49 static int coda_dentry_delete(struct dentry *);
50
51 /* support routines */
52 static int coda_venus_readdir(struct file *coda_file, void *buf,
53 filldir_t filldir);
54
55 /* same as fs/bad_inode.c */
56 static int coda_return_EIO(void)
57 {
58 return -EIO;
59 }
60 #define CODA_EIO_ERROR ((void *) (coda_return_EIO))
61
62 static const struct dentry_operations coda_dentry_operations =
63 {
64 .d_revalidate = coda_dentry_revalidate,
65 .d_delete = coda_dentry_delete,
66 };
67
68 const struct inode_operations coda_dir_inode_operations =
69 {
70 .create = coda_create,
71 .lookup = coda_lookup,
72 .link = coda_link,
73 .unlink = coda_unlink,
74 .symlink = coda_symlink,
75 .mkdir = coda_mkdir,
76 .rmdir = coda_rmdir,
77 .mknod = CODA_EIO_ERROR,
78 .rename = coda_rename,
79 .permission = coda_permission,
80 .getattr = coda_getattr,
81 .setattr = coda_setattr,
82 };
83
84 const struct file_operations coda_dir_operations = {
85 .llseek = generic_file_llseek,
86 .read = generic_read_dir,
87 .readdir = coda_readdir,
88 .open = coda_open,
89 .release = coda_release,
90 .fsync = coda_fsync,
91 };
92
93
94 /* inode operations for directories */
95 /* access routines: lookup, readlink, permission */
96 static struct dentry *coda_lookup(struct inode *dir, struct dentry *entry, struct nameidata *nd)
97 {
98 struct inode *inode = NULL;
99 struct CodaFid resfid = { { 0, } };
100 int type = 0;
101 int error = 0;
102 const char *name = entry->d_name.name;
103 size_t length = entry->d_name.len;
104
105 if (length > CODA_MAXNAMLEN) {
106 printk(KERN_ERR "name too long: lookup, %s (%*s)\n",
107 coda_i2s(dir), (int)length, name);
108 return ERR_PTR(-ENAMETOOLONG);
109 }
110
111 /* control object, create inode on the fly */
112 if (coda_isroot(dir) && coda_iscontrol(name, length)) {
113 error = coda_cnode_makectl(&inode, dir->i_sb);
114 type = CODA_NOCACHE;
115 goto exit;
116 }
117
118 lock_kernel();
119
120 error = venus_lookup(dir->i_sb, coda_i2f(dir), name, length,
121 &type, &resfid);
122 if (!error)
123 error = coda_cnode_make(&inode, &resfid, dir->i_sb);
124
125 unlock_kernel();
126
127 if (error && error != -ENOENT)
128 return ERR_PTR(error);
129
130 exit:
131 entry->d_op = &coda_dentry_operations;
132
133 if (inode && (type & CODA_NOCACHE))
134 coda_flag_inode(inode, C_VATTR | C_PURGE);
135
136 return d_splice_alias(inode, entry);
137 }
138
139
140 int coda_permission(struct inode *inode, int mask)
141 {
142 int error = 0;
143
144 mask &= MAY_READ | MAY_WRITE | MAY_EXEC;
145
146 if (!mask)
147 return 0;
148
149 if ((mask & MAY_EXEC) && !execute_ok(inode))
150 return -EACCES;
151
152 lock_kernel();
153
154 if (coda_cache_check(inode, mask))
155 goto out;
156
157 error = venus_access(inode->i_sb, coda_i2f(inode), mask);
158
159 if (!error)
160 coda_cache_enter(inode, mask);
161
162 out:
163 unlock_kernel();
164 return error;
165 }
166
167
168 static inline void coda_dir_update_mtime(struct inode *dir)
169 {
170 #ifdef REQUERY_VENUS_FOR_MTIME
171 /* invalidate the directory cnode's attributes so we refetch the
172 * attributes from venus next time the inode is referenced */
173 coda_flag_inode(dir, C_VATTR);
174 #else
175 /* optimistically we can also act as if our nose bleeds. The
176 * granularity of the mtime is coarse anyways so we might actually be
177 * right most of the time. Note: we only do this for directories. */
178 dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
179 #endif
180 }
181
182 /* we have to wrap inc_nlink/drop_nlink because sometimes userspace uses a
183 * trick to fool GNU find's optimizations. If we can't be sure of the link
184 * (because of volume mount points) we set i_nlink to 1 which forces find
185 * to consider every child as a possible directory. We should also never
186 * see an increment or decrement for deleted directories where i_nlink == 0 */
187 static inline void coda_dir_inc_nlink(struct inode *dir)
188 {
189 if (dir->i_nlink >= 2)
190 inc_nlink(dir);
191 }
192
193 static inline void coda_dir_drop_nlink(struct inode *dir)
194 {
195 if (dir->i_nlink > 2)
196 drop_nlink(dir);
197 }
198
199 /* creation routines: create, mknod, mkdir, link, symlink */
200 static int coda_create(struct inode *dir, struct dentry *de, int mode, struct nameidata *nd)
201 {
202 int error=0;
203 const char *name=de->d_name.name;
204 int length=de->d_name.len;
205 struct inode *inode;
206 struct CodaFid newfid;
207 struct coda_vattr attrs;
208
209 lock_kernel();
210
211 if (coda_isroot(dir) && coda_iscontrol(name, length)) {
212 unlock_kernel();
213 return -EPERM;
214 }
215
216 error = venus_create(dir->i_sb, coda_i2f(dir), name, length,
217 0, mode, &newfid, &attrs);
218
219 if ( error ) {
220 unlock_kernel();
221 d_drop(de);
222 return error;
223 }
224
225 inode = coda_iget(dir->i_sb, &newfid, &attrs);
226 if ( IS_ERR(inode) ) {
227 unlock_kernel();
228 d_drop(de);
229 return PTR_ERR(inode);
230 }
231
232 /* invalidate the directory cnode's attributes */
233 coda_dir_update_mtime(dir);
234 unlock_kernel();
235 d_instantiate(de, inode);
236 return 0;
237 }
238
239 static int coda_mkdir(struct inode *dir, struct dentry *de, int mode)
240 {
241 struct inode *inode;
242 struct coda_vattr attrs;
243 const char *name = de->d_name.name;
244 int len = de->d_name.len;
245 int error;
246 struct CodaFid newfid;
247
248 lock_kernel();
249
250 if (coda_isroot(dir) && coda_iscontrol(name, len)) {
251 unlock_kernel();
252 return -EPERM;
253 }
254
255 attrs.va_mode = mode;
256 error = venus_mkdir(dir->i_sb, coda_i2f(dir),
257 name, len, &newfid, &attrs);
258
259 if ( error ) {
260 unlock_kernel();
261 d_drop(de);
262 return error;
263 }
264
265 inode = coda_iget(dir->i_sb, &newfid, &attrs);
266 if ( IS_ERR(inode) ) {
267 unlock_kernel();
268 d_drop(de);
269 return PTR_ERR(inode);
270 }
271
272 /* invalidate the directory cnode's attributes */
273 coda_dir_inc_nlink(dir);
274 coda_dir_update_mtime(dir);
275 unlock_kernel();
276 d_instantiate(de, inode);
277 return 0;
278 }
279
280 /* try to make de an entry in dir_inodde linked to source_de */
281 static int coda_link(struct dentry *source_de, struct inode *dir_inode,
282 struct dentry *de)
283 {
284 struct inode *inode = source_de->d_inode;
285 const char * name = de->d_name.name;
286 int len = de->d_name.len;
287 int error;
288
289 lock_kernel();
290
291 if (coda_isroot(dir_inode) && coda_iscontrol(name, len)) {
292 unlock_kernel();
293 return -EPERM;
294 }
295
296 error = venus_link(dir_inode->i_sb, coda_i2f(inode),
297 coda_i2f(dir_inode), (const char *)name, len);
298
299 if (error) {
300 d_drop(de);
301 goto out;
302 }
303
304 coda_dir_update_mtime(dir_inode);
305 atomic_inc(&inode->i_count);
306 d_instantiate(de, inode);
307 inc_nlink(inode);
308
309 out:
310 unlock_kernel();
311 return(error);
312 }
313
314
315 static int coda_symlink(struct inode *dir_inode, struct dentry *de,
316 const char *symname)
317 {
318 const char *name = de->d_name.name;
319 int len = de->d_name.len;
320 int symlen;
321 int error = 0;
322
323 lock_kernel();
324
325 if (coda_isroot(dir_inode) && coda_iscontrol(name, len)) {
326 unlock_kernel();
327 return -EPERM;
328 }
329
330 symlen = strlen(symname);
331 if ( symlen > CODA_MAXPATHLEN ) {
332 unlock_kernel();
333 return -ENAMETOOLONG;
334 }
335
336 /*
337 * This entry is now negative. Since we do not create
338 * an inode for the entry we have to drop it.
339 */
340 d_drop(de);
341 error = venus_symlink(dir_inode->i_sb, coda_i2f(dir_inode), name, len,
342 symname, symlen);
343
344 /* mtime is no good anymore */
345 if ( !error )
346 coda_dir_update_mtime(dir_inode);
347
348 unlock_kernel();
349 return error;
350 }
351
352 /* destruction routines: unlink, rmdir */
353 static int coda_unlink(struct inode *dir, struct dentry *de)
354 {
355 int error;
356 const char *name = de->d_name.name;
357 int len = de->d_name.len;
358
359 lock_kernel();
360
361 error = venus_remove(dir->i_sb, coda_i2f(dir), name, len);
362 if ( error ) {
363 unlock_kernel();
364 return error;
365 }
366
367 coda_dir_update_mtime(dir);
368 drop_nlink(de->d_inode);
369 unlock_kernel();
370 return 0;
371 }
372
373 static int coda_rmdir(struct inode *dir, struct dentry *de)
374 {
375 const char *name = de->d_name.name;
376 int len = de->d_name.len;
377 int error;
378
379 lock_kernel();
380
381 error = venus_rmdir(dir->i_sb, coda_i2f(dir), name, len);
382 if (!error) {
383 /* VFS may delete the child */
384 if (de->d_inode)
385 de->d_inode->i_nlink = 0;
386
387 /* fix the link count of the parent */
388 coda_dir_drop_nlink(dir);
389 coda_dir_update_mtime(dir);
390 }
391 unlock_kernel();
392 return error;
393 }
394
395 /* rename */
396 static int coda_rename(struct inode *old_dir, struct dentry *old_dentry,
397 struct inode *new_dir, struct dentry *new_dentry)
398 {
399 const char *old_name = old_dentry->d_name.name;
400 const char *new_name = new_dentry->d_name.name;
401 int old_length = old_dentry->d_name.len;
402 int new_length = new_dentry->d_name.len;
403 int error;
404
405 lock_kernel();
406
407 error = venus_rename(old_dir->i_sb, coda_i2f(old_dir),
408 coda_i2f(new_dir), old_length, new_length,
409 (const char *) old_name, (const char *)new_name);
410
411 if ( !error ) {
412 if ( new_dentry->d_inode ) {
413 if ( S_ISDIR(new_dentry->d_inode->i_mode) ) {
414 coda_dir_drop_nlink(old_dir);
415 coda_dir_inc_nlink(new_dir);
416 }
417 coda_dir_update_mtime(old_dir);
418 coda_dir_update_mtime(new_dir);
419 coda_flag_inode(new_dentry->d_inode, C_VATTR);
420 } else {
421 coda_flag_inode(old_dir, C_VATTR);
422 coda_flag_inode(new_dir, C_VATTR);
423 }
424 }
425 unlock_kernel();
426
427 return error;
428 }
429
430
431 /* file operations for directories */
432 static int coda_readdir(struct file *coda_file, void *buf, filldir_t filldir)
433 {
434 struct coda_file_info *cfi;
435 struct file *host_file;
436 int ret;
437
438 cfi = CODA_FTOC(coda_file);
439 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
440 host_file = cfi->cfi_container;
441
442 if (!host_file->f_op)
443 return -ENOTDIR;
444
445 if (host_file->f_op->readdir)
446 {
447 /* potemkin case: we were handed a directory inode.
448 * We can't use vfs_readdir because we have to keep the file
449 * position in sync between the coda_file and the host_file.
450 * and as such we need grab the inode mutex. */
451 struct inode *host_inode = host_file->f_path.dentry->d_inode;
452
453 mutex_lock(&host_inode->i_mutex);
454 host_file->f_pos = coda_file->f_pos;
455
456 ret = -ENOENT;
457 if (!IS_DEADDIR(host_inode)) {
458 ret = host_file->f_op->readdir(host_file, buf, filldir);
459 file_accessed(host_file);
460 }
461
462 coda_file->f_pos = host_file->f_pos;
463 mutex_unlock(&host_inode->i_mutex);
464 }
465 else /* Venus: we must read Venus dirents from a file */
466 ret = coda_venus_readdir(coda_file, buf, filldir);
467
468 return ret;
469 }
470
471 static inline unsigned int CDT2DT(unsigned char cdt)
472 {
473 unsigned int dt;
474
475 switch(cdt) {
476 case CDT_UNKNOWN: dt = DT_UNKNOWN; break;
477 case CDT_FIFO: dt = DT_FIFO; break;
478 case CDT_CHR: dt = DT_CHR; break;
479 case CDT_DIR: dt = DT_DIR; break;
480 case CDT_BLK: dt = DT_BLK; break;
481 case CDT_REG: dt = DT_REG; break;
482 case CDT_LNK: dt = DT_LNK; break;
483 case CDT_SOCK: dt = DT_SOCK; break;
484 case CDT_WHT: dt = DT_WHT; break;
485 default: dt = DT_UNKNOWN; break;
486 }
487 return dt;
488 }
489
490 /* support routines */
491 static int coda_venus_readdir(struct file *coda_file, void *buf,
492 filldir_t filldir)
493 {
494 int result = 0; /* # of entries returned */
495 struct coda_file_info *cfi;
496 struct coda_inode_info *cii;
497 struct file *host_file;
498 struct dentry *de;
499 struct venus_dirent *vdir;
500 unsigned long vdir_size =
501 (unsigned long)(&((struct venus_dirent *)0)->d_name);
502 unsigned int type;
503 struct qstr name;
504 ino_t ino;
505 int ret;
506
507 cfi = CODA_FTOC(coda_file);
508 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
509 host_file = cfi->cfi_container;
510
511 de = coda_file->f_path.dentry;
512 cii = ITOC(de->d_inode);
513
514 vdir = kmalloc(sizeof(*vdir), GFP_KERNEL);
515 if (!vdir) return -ENOMEM;
516
517 if (coda_file->f_pos == 0) {
518 ret = filldir(buf, ".", 1, 0, de->d_inode->i_ino, DT_DIR);
519 if (ret < 0)
520 goto out;
521 result++;
522 coda_file->f_pos++;
523 }
524 if (coda_file->f_pos == 1) {
525 ret = filldir(buf, "..", 2, 1, de->d_parent->d_inode->i_ino, DT_DIR);
526 if (ret < 0)
527 goto out;
528 result++;
529 coda_file->f_pos++;
530 }
531 while (1) {
532 /* read entries from the directory file */
533 ret = kernel_read(host_file, coda_file->f_pos - 2, (char *)vdir,
534 sizeof(*vdir));
535 if (ret < 0) {
536 printk(KERN_ERR "coda readdir: read dir %s failed %d\n",
537 coda_f2s(&cii->c_fid), ret);
538 break;
539 }
540 if (ret == 0) break; /* end of directory file reached */
541
542 /* catch truncated reads */
543 if (ret < vdir_size || ret < vdir_size + vdir->d_namlen) {
544 printk(KERN_ERR "coda readdir: short read on %s\n",
545 coda_f2s(&cii->c_fid));
546 ret = -EBADF;
547 break;
548 }
549 /* validate whether the directory file actually makes sense */
550 if (vdir->d_reclen < vdir_size + vdir->d_namlen) {
551 printk(KERN_ERR "coda readdir: invalid dir %s\n",
552 coda_f2s(&cii->c_fid));
553 ret = -EBADF;
554 break;
555 }
556
557 name.len = vdir->d_namlen;
558 name.name = vdir->d_name;
559
560 /* Make sure we skip '.' and '..', we already got those */
561 if (name.name[0] == '.' && (name.len == 1 ||
562 (vdir->d_name[1] == '.' && name.len == 2)))
563 vdir->d_fileno = name.len = 0;
564
565 /* skip null entries */
566 if (vdir->d_fileno && name.len) {
567 /* try to look up this entry in the dcache, that way
568 * userspace doesn't have to worry about breaking
569 * getcwd by having mismatched inode numbers for
570 * internal volume mountpoints. */
571 ino = find_inode_number(de, &name);
572 if (!ino) ino = vdir->d_fileno;
573
574 type = CDT2DT(vdir->d_type);
575 ret = filldir(buf, name.name, name.len,
576 coda_file->f_pos, ino, type);
577 /* failure means no space for filling in this round */
578 if (ret < 0) break;
579 result++;
580 }
581 /* we'll always have progress because d_reclen is unsigned and
582 * we've already established it is non-zero. */
583 coda_file->f_pos += vdir->d_reclen;
584 }
585 out:
586 kfree(vdir);
587 return result ? result : ret;
588 }
589
590 /* called when a cache lookup succeeds */
591 static int coda_dentry_revalidate(struct dentry *de, struct nameidata *nd)
592 {
593 struct inode *inode = de->d_inode;
594 struct coda_inode_info *cii;
595
596 if (!inode)
597 return 1;
598 lock_kernel();
599 if (coda_isroot(inode))
600 goto out;
601 if (is_bad_inode(inode))
602 goto bad;
603
604 cii = ITOC(de->d_inode);
605 if (!(cii->c_flags & (C_PURGE | C_FLUSH)))
606 goto out;
607
608 shrink_dcache_parent(de);
609
610 /* propagate for a flush */
611 if (cii->c_flags & C_FLUSH)
612 coda_flag_inode_children(inode, C_FLUSH);
613
614 if (atomic_read(&de->d_count) > 1)
615 /* pretend it's valid, but don't change the flags */
616 goto out;
617
618 /* clear the flags. */
619 cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);
620
621 bad:
622 unlock_kernel();
623 return 0;
624 out:
625 unlock_kernel();
626 return 1;
627 }
628
629 /*
630 * This is the callback from dput() when d_count is going to 0.
631 * We use this to unhash dentries with bad inodes.
632 */
633 static int coda_dentry_delete(struct dentry * dentry)
634 {
635 int flags;
636
637 if (!dentry->d_inode)
638 return 0;
639
640 flags = (ITOC(dentry->d_inode)->c_flags) & C_PURGE;
641 if (is_bad_inode(dentry->d_inode) || flags) {
642 return 1;
643 }
644 return 0;
645 }
646
647
648
649 /*
650 * This is called when we want to check if the inode has
651 * changed on the server. Coda makes this easy since the
652 * cache manager Venus issues a downcall to the kernel when this
653 * happens
654 */
655 int coda_revalidate_inode(struct dentry *dentry)
656 {
657 struct coda_vattr attr;
658 int error = 0;
659 int old_mode;
660 ino_t old_ino;
661 struct inode *inode = dentry->d_inode;
662 struct coda_inode_info *cii = ITOC(inode);
663
664 lock_kernel();
665 if ( !cii->c_flags )
666 goto ok;
667
668 if (cii->c_flags & (C_VATTR | C_PURGE | C_FLUSH)) {
669 error = venus_getattr(inode->i_sb, &(cii->c_fid), &attr);
670 if ( error )
671 goto return_bad;
672
673 /* this inode may be lost if:
674 - it's ino changed
675 - type changes must be permitted for repair and
676 missing mount points.
677 */
678 old_mode = inode->i_mode;
679 old_ino = inode->i_ino;
680 coda_vattr_to_iattr(inode, &attr);
681
682 if ((old_mode & S_IFMT) != (inode->i_mode & S_IFMT)) {
683 printk("Coda: inode %ld, fid %s changed type!\n",
684 inode->i_ino, coda_f2s(&(cii->c_fid)));
685 }
686
687 /* the following can happen when a local fid is replaced
688 with a global one, here we lose and declare the inode bad */
689 if (inode->i_ino != old_ino)
690 goto return_bad;
691
692 coda_flag_inode_children(inode, C_FLUSH);
693 cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);
694 }
695
696 ok:
697 unlock_kernel();
698 return 0;
699
700 return_bad:
701 unlock_kernel();
702 return -EIO;
703 }
Linux with added FPC-III support