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[linux-2.6.git] / fs / coda / dir.c
blobccd98b0f2b0b9c3d37f10b101a86b36572054240
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/slab.h>
16 #include <linux/file.h>
17 #include <linux/stat.h>
18 #include <linux/errno.h>
19 #include <linux/string.h>
20 #include <linux/smp_lock.h>
21
22 #include <asm/uaccess.h>
23
24 #include <linux/coda.h>
25 #include <linux/coda_linux.h>
26 #include <linux/coda_psdev.h>
27 #include <linux/coda_fs_i.h>
28 #include <linux/coda_cache.h>
29
30 #include "coda_int.h"
31
32 /* dir inode-ops */
33 static int coda_create(struct inode *dir, struct dentry *new, int mode, struct nameidata *nd);
34 static struct dentry *coda_lookup(struct inode *dir, struct dentry *target, struct nameidata *nd);
35 static int coda_link(struct dentry *old_dentry, struct inode *dir_inode,
36 struct dentry *entry);
37 static int coda_unlink(struct inode *dir_inode, struct dentry *entry);
38 static int coda_symlink(struct inode *dir_inode, struct dentry *entry,
39 const char *symname);
40 static int coda_mkdir(struct inode *dir_inode, struct dentry *entry, int mode);
41 static int coda_rmdir(struct inode *dir_inode, struct dentry *entry);
42 static int coda_rename(struct inode *old_inode, struct dentry *old_dentry,
43 struct inode *new_inode, struct dentry *new_dentry);
44
45 /* dir file-ops */
46 static int coda_readdir(struct file *file, void *buf, filldir_t filldir);
47
48 /* dentry ops */
49 static int coda_dentry_revalidate(struct dentry *de, struct nameidata *nd);
50 static int coda_dentry_delete(struct dentry *);
51
52 /* support routines */
53 static int coda_venus_readdir(struct file *coda_file, void *buf,
54 filldir_t filldir);
55
56 /* same as fs/bad_inode.c */
57 static int coda_return_EIO(void)
58 {
59 return -EIO;
60 }
61 #define CODA_EIO_ERROR ((void *) (coda_return_EIO))
62
63 static const struct dentry_operations coda_dentry_operations =
64 {
65 .d_revalidate = coda_dentry_revalidate,
66 .d_delete = coda_dentry_delete,
67 };
68
69 const struct inode_operations coda_dir_inode_operations =
70 {
71 .create = coda_create,
72 .lookup = coda_lookup,
73 .link = coda_link,
74 .unlink = coda_unlink,
75 .symlink = coda_symlink,
76 .mkdir = coda_mkdir,
77 .rmdir = coda_rmdir,
78 .mknod = CODA_EIO_ERROR,
79 .rename = coda_rename,
80 .permission = coda_permission,
81 .getattr = coda_getattr,
82 .setattr = coda_setattr,
83 };
84
85 const struct file_operations coda_dir_operations = {
86 .llseek = generic_file_llseek,
87 .read = generic_read_dir,
88 .readdir = coda_readdir,
89 .open = coda_open,
90 .release = coda_release,
91 .fsync = coda_fsync,
92 };
93
94
95 /* inode operations for directories */
96 /* access routines: lookup, readlink, permission */
97 static struct dentry *coda_lookup(struct inode *dir, struct dentry *entry, struct nameidata *nd)
98 {
99 struct inode *inode = NULL;
100 struct CodaFid resfid = { { 0, } };
101 int type = 0;
102 int error = 0;
103 const char *name = entry->d_name.name;
104 size_t length = entry->d_name.len;
105
106 if (length > CODA_MAXNAMLEN) {
107 printk(KERN_ERR "name too long: lookup, %s (%*s)\n",
108 coda_i2s(dir), (int)length, name);
109 return ERR_PTR(-ENAMETOOLONG);
110 }
111
112 /* control object, create inode on the fly */
113 if (coda_isroot(dir) && coda_iscontrol(name, length)) {
114 error = coda_cnode_makectl(&inode, dir->i_sb);
115 type = CODA_NOCACHE;
116 goto exit;
117 }
118
119 lock_kernel();
120
121 error = venus_lookup(dir->i_sb, coda_i2f(dir), name, length,
122 &type, &resfid);
123 if (!error)
124 error = coda_cnode_make(&inode, &resfid, dir->i_sb);
125
126 unlock_kernel();
127
128 if (error && error != -ENOENT)
129 return ERR_PTR(error);
130
131 exit:
132 entry->d_op = &coda_dentry_operations;
133
134 if (inode && (type & CODA_NOCACHE))
135 coda_flag_inode(inode, C_VATTR | C_PURGE);
136
137 return d_splice_alias(inode, entry);
138 }
139
140
141 int coda_permission(struct inode *inode, int mask)
142 {
143 int error = 0;
144
145 mask &= MAY_READ | MAY_WRITE | MAY_EXEC;
146
147 if (!mask)
148 return 0;
149
150 if ((mask & MAY_EXEC) && !execute_ok(inode))
151 return -EACCES;
152
153 lock_kernel();
154
155 if (coda_cache_check(inode, mask))
156 goto out;
157
158 error = venus_access(inode->i_sb, coda_i2f(inode), mask);
159
160 if (!error)
161 coda_cache_enter(inode, mask);
162
163 out:
164 unlock_kernel();
165 return error;
166 }
167
168
169 static inline void coda_dir_update_mtime(struct inode *dir)
170 {
171 #ifdef REQUERY_VENUS_FOR_MTIME
172 /* invalidate the directory cnode's attributes so we refetch the
173 * attributes from venus next time the inode is referenced */
174 coda_flag_inode(dir, C_VATTR);
175 #else
176 /* optimistically we can also act as if our nose bleeds. The
177 * granularity of the mtime is coarse anyways so we might actually be
178 * right most of the time. Note: we only do this for directories. */
179 dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
180 #endif
181 }
182
183 /* we have to wrap inc_nlink/drop_nlink because sometimes userspace uses a
184 * trick to fool GNU find's optimizations. If we can't be sure of the link
185 * (because of volume mount points) we set i_nlink to 1 which forces find
186 * to consider every child as a possible directory. We should also never
187 * see an increment or decrement for deleted directories where i_nlink == 0 */
188 static inline void coda_dir_inc_nlink(struct inode *dir)
189 {
190 if (dir->i_nlink >= 2)
191 inc_nlink(dir);
192 }
193
194 static inline void coda_dir_drop_nlink(struct inode *dir)
195 {
196 if (dir->i_nlink > 2)
197 drop_nlink(dir);
198 }
199
200 /* creation routines: create, mknod, mkdir, link, symlink */
201 static int coda_create(struct inode *dir, struct dentry *de, int mode, struct nameidata *nd)
202 {
203 int error=0;
204 const char *name=de->d_name.name;
205 int length=de->d_name.len;
206 struct inode *inode;
207 struct CodaFid newfid;
208 struct coda_vattr attrs;
209
210 lock_kernel();
211
212 if (coda_isroot(dir) && coda_iscontrol(name, length)) {
213 unlock_kernel();
214 return -EPERM;
215 }
216
217 error = venus_create(dir->i_sb, coda_i2f(dir), name, length,
218 0, mode, &newfid, &attrs);
219
220 if ( error ) {
221 unlock_kernel();
222 d_drop(de);
223 return error;
224 }
225
226 inode = coda_iget(dir->i_sb, &newfid, &attrs);
227 if ( IS_ERR(inode) ) {
228 unlock_kernel();
229 d_drop(de);
230 return PTR_ERR(inode);
231 }
232
233 /* invalidate the directory cnode's attributes */
234 coda_dir_update_mtime(dir);
235 unlock_kernel();
236 d_instantiate(de, inode);
237 return 0;
238 }
239
240 static int coda_mkdir(struct inode *dir, struct dentry *de, int mode)
241 {
242 struct inode *inode;
243 struct coda_vattr attrs;
244 const char *name = de->d_name.name;
245 int len = de->d_name.len;
246 int error;
247 struct CodaFid newfid;
248
249 lock_kernel();
250
251 if (coda_isroot(dir) && coda_iscontrol(name, len)) {
252 unlock_kernel();
253 return -EPERM;
254 }
255
256 attrs.va_mode = mode;
257 error = venus_mkdir(dir->i_sb, coda_i2f(dir),
258 name, len, &newfid, &attrs);
259
260 if ( error ) {
261 unlock_kernel();
262 d_drop(de);
263 return error;
264 }
265
266 inode = coda_iget(dir->i_sb, &newfid, &attrs);
267 if ( IS_ERR(inode) ) {
268 unlock_kernel();
269 d_drop(de);
270 return PTR_ERR(inode);
271 }
272
273 /* invalidate the directory cnode's attributes */
274 coda_dir_inc_nlink(dir);
275 coda_dir_update_mtime(dir);
276 unlock_kernel();
277 d_instantiate(de, inode);
278 return 0;
279 }
280
281 /* try to make de an entry in dir_inodde linked to source_de */
282 static int coda_link(struct dentry *source_de, struct inode *dir_inode,
283 struct dentry *de)
284 {
285 struct inode *inode = source_de->d_inode;
286 const char * name = de->d_name.name;
287 int len = de->d_name.len;
288 int error;
289
290 lock_kernel();
291
292 if (coda_isroot(dir_inode) && coda_iscontrol(name, len)) {
293 unlock_kernel();
294 return -EPERM;
295 }
296
297 error = venus_link(dir_inode->i_sb, coda_i2f(inode),
298 coda_i2f(dir_inode), (const char *)name, len);
299
300 if (error) {
301 d_drop(de);
302 goto out;
303 }
304
305 coda_dir_update_mtime(dir_inode);
306 atomic_inc(&inode->i_count);
307 d_instantiate(de, inode);
308 inc_nlink(inode);
309
310 out:
311 unlock_kernel();
312 return(error);
313 }
314
315
316 static int coda_symlink(struct inode *dir_inode, struct dentry *de,
317 const char *symname)
318 {
319 const char *name = de->d_name.name;
320 int len = de->d_name.len;
321 int symlen;
322 int error = 0;
323
324 lock_kernel();
325
326 if (coda_isroot(dir_inode) && coda_iscontrol(name, len)) {
327 unlock_kernel();
328 return -EPERM;
329 }
330
331 symlen = strlen(symname);
332 if ( symlen > CODA_MAXPATHLEN ) {
333 unlock_kernel();
334 return -ENAMETOOLONG;
335 }
336
337 /*
338 * This entry is now negative. Since we do not create
339 * an inode for the entry we have to drop it.
340 */
341 d_drop(de);
342 error = venus_symlink(dir_inode->i_sb, coda_i2f(dir_inode), name, len,
343 symname, symlen);
344
345 /* mtime is no good anymore */
346 if ( !error )
347 coda_dir_update_mtime(dir_inode);
348
349 unlock_kernel();
350 return error;
351 }
352
353 /* destruction routines: unlink, rmdir */
354 static int coda_unlink(struct inode *dir, struct dentry *de)
355 {
356 int error;
357 const char *name = de->d_name.name;
358 int len = de->d_name.len;
359
360 lock_kernel();
361
362 error = venus_remove(dir->i_sb, coda_i2f(dir), name, len);
363 if ( error ) {
364 unlock_kernel();
365 return error;
366 }
367
368 coda_dir_update_mtime(dir);
369 drop_nlink(de->d_inode);
370 unlock_kernel();
371 return 0;
372 }
373
374 static int coda_rmdir(struct inode *dir, struct dentry *de)
375 {
376 const char *name = de->d_name.name;
377 int len = de->d_name.len;
378 int error;
379
380 lock_kernel();
381
382 error = venus_rmdir(dir->i_sb, coda_i2f(dir), name, len);
383 if (!error) {
384 /* VFS may delete the child */
385 if (de->d_inode)
386 de->d_inode->i_nlink = 0;
387
388 /* fix the link count of the parent */
389 coda_dir_drop_nlink(dir);
390 coda_dir_update_mtime(dir);
391 }
392 unlock_kernel();
393 return error;
394 }
395
396 /* rename */
397 static int coda_rename(struct inode *old_dir, struct dentry *old_dentry,
398 struct inode *new_dir, struct dentry *new_dentry)
399 {
400 const char *old_name = old_dentry->d_name.name;
401 const char *new_name = new_dentry->d_name.name;
402 int old_length = old_dentry->d_name.len;
403 int new_length = new_dentry->d_name.len;
404 int error;
405
406 lock_kernel();
407
408 error = venus_rename(old_dir->i_sb, coda_i2f(old_dir),
409 coda_i2f(new_dir), old_length, new_length,
410 (const char *) old_name, (const char *)new_name);
411
412 if ( !error ) {
413 if ( new_dentry->d_inode ) {
414 if ( S_ISDIR(new_dentry->d_inode->i_mode) ) {
415 coda_dir_drop_nlink(old_dir);
416 coda_dir_inc_nlink(new_dir);
417 }
418 coda_dir_update_mtime(old_dir);
419 coda_dir_update_mtime(new_dir);
420 coda_flag_inode(new_dentry->d_inode, C_VATTR);
421 } else {
422 coda_flag_inode(old_dir, C_VATTR);
423 coda_flag_inode(new_dir, C_VATTR);
424 }
425 }
426 unlock_kernel();
427
428 return error;
429 }
430
431
432 /* file operations for directories */
433 static int coda_readdir(struct file *coda_file, void *buf, filldir_t filldir)
434 {
435 struct coda_file_info *cfi;
436 struct file *host_file;
437 int ret;
438
439 cfi = CODA_FTOC(coda_file);
440 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
441 host_file = cfi->cfi_container;
442
443 if (!host_file->f_op)
444 return -ENOTDIR;
445
446 if (host_file->f_op->readdir)
447 {
448 /* potemkin case: we were handed a directory inode.
449 * We can't use vfs_readdir because we have to keep the file
450 * position in sync between the coda_file and the host_file.
451 * and as such we need grab the inode mutex. */
452 struct inode *host_inode = host_file->f_path.dentry->d_inode;
453
454 mutex_lock(&host_inode->i_mutex);
455 host_file->f_pos = coda_file->f_pos;
456
457 ret = -ENOENT;
458 if (!IS_DEADDIR(host_inode)) {
459 ret = host_file->f_op->readdir(host_file, buf, filldir);
460 file_accessed(host_file);
461 }
462
463 coda_file->f_pos = host_file->f_pos;
464 mutex_unlock(&host_inode->i_mutex);
465 }
466 else /* Venus: we must read Venus dirents from a file */
467 ret = coda_venus_readdir(coda_file, buf, filldir);
468
469 return ret;
470 }
471
472 static inline unsigned int CDT2DT(unsigned char cdt)
473 {
474 unsigned int dt;
475
476 switch(cdt) {
477 case CDT_UNKNOWN: dt = DT_UNKNOWN; break;
478 case CDT_FIFO: dt = DT_FIFO; break;
479 case CDT_CHR: dt = DT_CHR; break;
480 case CDT_DIR: dt = DT_DIR; break;
481 case CDT_BLK: dt = DT_BLK; break;
482 case CDT_REG: dt = DT_REG; break;
483 case CDT_LNK: dt = DT_LNK; break;
484 case CDT_SOCK: dt = DT_SOCK; break;
485 case CDT_WHT: dt = DT_WHT; break;
486 default: dt = DT_UNKNOWN; break;
487 }
488 return dt;
489 }
490
491 /* support routines */
492 static int coda_venus_readdir(struct file *coda_file, void *buf,
493 filldir_t filldir)
494 {
495 int result = 0; /* # of entries returned */
496 struct coda_file_info *cfi;
497 struct coda_inode_info *cii;
498 struct file *host_file;
499 struct dentry *de;
500 struct venus_dirent *vdir;
501 unsigned long vdir_size =
502 (unsigned long)(&((struct venus_dirent *)0)->d_name);
503 unsigned int type;
504 struct qstr name;
505 ino_t ino;
506 int ret;
507
508 cfi = CODA_FTOC(coda_file);
509 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
510 host_file = cfi->cfi_container;
511
512 de = coda_file->f_path.dentry;
513 cii = ITOC(de->d_inode);
514
515 vdir = kmalloc(sizeof(*vdir), GFP_KERNEL);
516 if (!vdir) return -ENOMEM;
517
518 if (coda_file->f_pos == 0) {
519 ret = filldir(buf, ".", 1, 0, de->d_inode->i_ino, DT_DIR);
520 if (ret < 0)
521 goto out;
522 result++;
523 coda_file->f_pos++;
524 }
525 if (coda_file->f_pos == 1) {
526 ret = filldir(buf, "..", 2, 1, de->d_parent->d_inode->i_ino, DT_DIR);
527 if (ret < 0)
528 goto out;
529 result++;
530 coda_file->f_pos++;
531 }
532 while (1) {
533 /* read entries from the directory file */
534 ret = kernel_read(host_file, coda_file->f_pos - 2, (char *)vdir,
535 sizeof(*vdir));
536 if (ret < 0) {
537 printk(KERN_ERR "coda readdir: read dir %s failed %d\n",
538 coda_f2s(&cii->c_fid), ret);
539 break;
540 }
541 if (ret == 0) break; /* end of directory file reached */
542
543 /* catch truncated reads */
544 if (ret < vdir_size || ret < vdir_size + vdir->d_namlen) {
545 printk(KERN_ERR "coda readdir: short read on %s\n",
546 coda_f2s(&cii->c_fid));
547 ret = -EBADF;
548 break;
549 }
550 /* validate whether the directory file actually makes sense */
551 if (vdir->d_reclen < vdir_size + vdir->d_namlen) {
552 printk(KERN_ERR "coda readdir: invalid dir %s\n",
553 coda_f2s(&cii->c_fid));
554 ret = -EBADF;
555 break;
556 }
557
558 name.len = vdir->d_namlen;
559 name.name = vdir->d_name;
560
561 /* Make sure we skip '.' and '..', we already got those */
562 if (name.name[0] == '.' && (name.len == 1 ||
563 (vdir->d_name[1] == '.' && name.len == 2)))
564 vdir->d_fileno = name.len = 0;
565
566 /* skip null entries */
567 if (vdir->d_fileno && name.len) {
568 /* try to look up this entry in the dcache, that way
569 * userspace doesn't have to worry about breaking
570 * getcwd by having mismatched inode numbers for
571 * internal volume mountpoints. */
572 ino = find_inode_number(de, &name);
573 if (!ino) ino = vdir->d_fileno;
574
575 type = CDT2DT(vdir->d_type);
576 ret = filldir(buf, name.name, name.len,
577 coda_file->f_pos, ino, type);
578 /* failure means no space for filling in this round */
579 if (ret < 0) break;
580 result++;
581 }
582 /* we'll always have progress because d_reclen is unsigned and
583 * we've already established it is non-zero. */
584 coda_file->f_pos += vdir->d_reclen;
585 }
586 out:
587 kfree(vdir);
588 return result ? result : ret;
589 }
590
591 /* called when a cache lookup succeeds */
592 static int coda_dentry_revalidate(struct dentry *de, struct nameidata *nd)
593 {
594 struct inode *inode = de->d_inode;
595 struct coda_inode_info *cii;
596
597 if (!inode)
598 return 1;
599 lock_kernel();
600 if (coda_isroot(inode))
601 goto out;
602 if (is_bad_inode(inode))
603 goto bad;
604
605 cii = ITOC(de->d_inode);
606 if (!(cii->c_flags & (C_PURGE | C_FLUSH)))
607 goto out;
608
609 shrink_dcache_parent(de);
610
611 /* propagate for a flush */
612 if (cii->c_flags & C_FLUSH)
613 coda_flag_inode_children(inode, C_FLUSH);
614
615 if (atomic_read(&de->d_count) > 1)
616 /* pretend it's valid, but don't change the flags */
617 goto out;
618
619 /* clear the flags. */
620 cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);
621
622 bad:
623 unlock_kernel();
624 return 0;
625 out:
626 unlock_kernel();
627 return 1;
628 }
629
630 /*
631 * This is the callback from dput() when d_count is going to 0.
632 * We use this to unhash dentries with bad inodes.
633 */
634 static int coda_dentry_delete(struct dentry * dentry)
635 {
636 int flags;
637
638 if (!dentry->d_inode)
639 return 0;
640
641 flags = (ITOC(dentry->d_inode)->c_flags) & C_PURGE;
642 if (is_bad_inode(dentry->d_inode) || flags) {
643 return 1;
644 }
645 return 0;
646 }
647
648
649
650 /*
651 * This is called when we want to check if the inode has
652 * changed on the server. Coda makes this easy since the
653 * cache manager Venus issues a downcall to the kernel when this
654 * happens
655 */
656 int coda_revalidate_inode(struct dentry *dentry)
657 {
658 struct coda_vattr attr;
659 int error = 0;
660 int old_mode;
661 ino_t old_ino;
662 struct inode *inode = dentry->d_inode;
663 struct coda_inode_info *cii = ITOC(inode);
664
665 lock_kernel();
666 if ( !cii->c_flags )
667 goto ok;
668
669 if (cii->c_flags & (C_VATTR | C_PURGE | C_FLUSH)) {
670 error = venus_getattr(inode->i_sb, &(cii->c_fid), &attr);
671 if ( error )
672 goto return_bad;
673
674 /* this inode may be lost if:
675 - it's ino changed
676 - type changes must be permitted for repair and
677 missing mount points.
678 */
679 old_mode = inode->i_mode;
680 old_ino = inode->i_ino;
681 coda_vattr_to_iattr(inode, &attr);
682
683 if ((old_mode & S_IFMT) != (inode->i_mode & S_IFMT)) {
684 printk("Coda: inode %ld, fid %s changed type!\n",
685 inode->i_ino, coda_f2s(&(cii->c_fid)));
686 }
687
688 /* the following can happen when a local fid is replaced
689 with a global one, here we lose and declare the inode bad */
690 if (inode->i_ino != old_ino)
691 goto return_bad;
692
693 coda_flag_inode_children(inode, C_FLUSH);
694 cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);
695 }
696
697 ok:
698 unlock_kernel();
699 return 0;
700
701 return_bad:
702 unlock_kernel();
703 return -EIO;
704 }
Linus' kernel tree