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coda: fix nlink updates for directories
[deliverable/linux.git] / fs / coda / dir.c
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 #include <linux/coda_proc.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 *dirent, 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 *filp, filldir_t filldir,
54 void *dirent, struct dentry *dir);
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 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 .flush = coda_flush,
91 .release = coda_release,
92 .fsync = coda_fsync,
93 };
94
95
96 /* inode operations for directories */
97 /* access routines: lookup, readlink, permission */
98 static struct dentry *coda_lookup(struct inode *dir, struct dentry *entry, struct nameidata *nd)
99 {
100 struct inode *res_inode = NULL;
101 struct CodaFid resfid = { { 0, } };
102 int dropme = 0; /* to indicate entry should not be cached */
103 int type = 0;
104 int error = 0;
105 const char *name = entry->d_name.name;
106 size_t length = entry->d_name.len;
107
108 if ( length > CODA_MAXNAMLEN ) {
109 printk("name too long: lookup, %s (%*s)\n",
110 coda_i2s(dir), (int)length, name);
111 return ERR_PTR(-ENAMETOOLONG);
112 }
113
114 lock_kernel();
115 /* control object, create inode on the fly */
116 if (coda_isroot(dir) && coda_iscontrol(name, length)) {
117 error = coda_cnode_makectl(&res_inode, dir->i_sb);
118 dropme = 1;
119 goto exit;
120 }
121
122 error = venus_lookup(dir->i_sb, coda_i2f(dir),
123 (const char *)name, length, &type, &resfid);
124
125 res_inode = NULL;
126 if (!error) {
127 if (type & CODA_NOCACHE) {
128 type &= (~CODA_NOCACHE);
129 dropme = 1;
130 }
131
132 error = coda_cnode_make(&res_inode, &resfid, dir->i_sb);
133 if (error) {
134 unlock_kernel();
135 return ERR_PTR(error);
136 }
137 } else if (error != -ENOENT) {
138 unlock_kernel();
139 return ERR_PTR(error);
140 }
141
142 exit:
143 entry->d_time = 0;
144 entry->d_op = &coda_dentry_operations;
145 d_add(entry, res_inode);
146 if ( dropme ) {
147 d_drop(entry);
148 coda_flag_inode(res_inode, C_VATTR);
149 }
150 unlock_kernel();
151 return NULL;
152 }
153
154
155 int coda_permission(struct inode *inode, int mask, struct nameidata *nd)
156 {
157 int error = 0;
158
159 if (!mask)
160 return 0;
161
162 lock_kernel();
163
164 coda_vfs_stat.permission++;
165
166 if (coda_cache_check(inode, mask))
167 goto out;
168
169 error = venus_access(inode->i_sb, coda_i2f(inode), mask);
170
171 if (!error)
172 coda_cache_enter(inode, mask);
173
174 out:
175 unlock_kernel();
176 return error;
177 }
178
179
180 static inline void coda_dir_update_mtime(struct inode *dir)
181 {
182 #ifdef REQUERY_VENUS_FOR_MTIME
183 /* invalidate the directory cnode's attributes so we refetch the
184 * attributes from venus next time the inode is referenced */
185 coda_flag_inode(dir, C_VATTR);
186 #else
187 /* optimistically we can also act as if our nose bleeds. The
188 * granularity of the mtime is coarse anyways so we might actually be
189 * right most of the time. Note: we only do this for directories. */
190 dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
191 #endif
192 }
193
194 /* we have to wrap inc_nlink/drop_nlink because sometimes userspace uses a
195 * trick to fool GNU find's optimizations. If we can't be sure of the link
196 * (because of volume mount points) we set i_nlink to 1 which forces find
197 * to consider every child as a possible directory. We should also never
198 * see an increment or decrement for deleted directories where i_nlink == 0 */
199 static inline void coda_dir_inc_nlink(struct inode *dir)
200 {
201 if (dir->i_nlink >= 2)
202 inc_nlink(dir);
203 }
204
205 static inline void coda_dir_drop_nlink(struct inode *dir)
206 {
207 if (dir->i_nlink > 2)
208 drop_nlink(dir);
209 }
210
211 /* creation routines: create, mknod, mkdir, link, symlink */
212 static int coda_create(struct inode *dir, struct dentry *de, int mode, struct nameidata *nd)
213 {
214 int error=0;
215 const char *name=de->d_name.name;
216 int length=de->d_name.len;
217 struct inode *inode;
218 struct CodaFid newfid;
219 struct coda_vattr attrs;
220
221 lock_kernel();
222 coda_vfs_stat.create++;
223
224 if (coda_isroot(dir) && coda_iscontrol(name, length)) {
225 unlock_kernel();
226 return -EPERM;
227 }
228
229 error = venus_create(dir->i_sb, coda_i2f(dir), name, length,
230 0, mode, &newfid, &attrs);
231
232 if ( error ) {
233 unlock_kernel();
234 d_drop(de);
235 return error;
236 }
237
238 inode = coda_iget(dir->i_sb, &newfid, &attrs);
239 if ( IS_ERR(inode) ) {
240 unlock_kernel();
241 d_drop(de);
242 return PTR_ERR(inode);
243 }
244
245 /* invalidate the directory cnode's attributes */
246 coda_dir_update_mtime(dir);
247 unlock_kernel();
248 d_instantiate(de, inode);
249 return 0;
250 }
251
252 static int coda_mkdir(struct inode *dir, struct dentry *de, int mode)
253 {
254 struct inode *inode;
255 struct coda_vattr attrs;
256 const char *name = de->d_name.name;
257 int len = de->d_name.len;
258 int error;
259 struct CodaFid newfid;
260
261 lock_kernel();
262 coda_vfs_stat.mkdir++;
263
264 if (coda_isroot(dir) && coda_iscontrol(name, len)) {
265 unlock_kernel();
266 return -EPERM;
267 }
268
269 attrs.va_mode = mode;
270 error = venus_mkdir(dir->i_sb, coda_i2f(dir),
271 name, len, &newfid, &attrs);
272
273 if ( error ) {
274 unlock_kernel();
275 d_drop(de);
276 return error;
277 }
278
279 inode = coda_iget(dir->i_sb, &newfid, &attrs);
280 if ( IS_ERR(inode) ) {
281 unlock_kernel();
282 d_drop(de);
283 return PTR_ERR(inode);
284 }
285
286 /* invalidate the directory cnode's attributes */
287 coda_dir_inc_nlink(dir);
288 coda_dir_update_mtime(dir);
289 unlock_kernel();
290 d_instantiate(de, inode);
291 return 0;
292 }
293
294 /* try to make de an entry in dir_inodde linked to source_de */
295 static int coda_link(struct dentry *source_de, struct inode *dir_inode,
296 struct dentry *de)
297 {
298 struct inode *inode = source_de->d_inode;
299 const char * name = de->d_name.name;
300 int len = de->d_name.len;
301 int error;
302
303 lock_kernel();
304 coda_vfs_stat.link++;
305
306 if (coda_isroot(dir_inode) && coda_iscontrol(name, len)) {
307 unlock_kernel();
308 return -EPERM;
309 }
310
311 error = venus_link(dir_inode->i_sb, coda_i2f(inode),
312 coda_i2f(dir_inode), (const char *)name, len);
313
314 if (error) {
315 d_drop(de);
316 goto out;
317 }
318
319 coda_dir_update_mtime(dir_inode);
320 atomic_inc(&inode->i_count);
321 d_instantiate(de, inode);
322 inc_nlink(inode);
323
324 out:
325 unlock_kernel();
326 return(error);
327 }
328
329
330 static int coda_symlink(struct inode *dir_inode, struct dentry *de,
331 const char *symname)
332 {
333 const char *name = de->d_name.name;
334 int len = de->d_name.len;
335 int symlen;
336 int error=0;
337
338 lock_kernel();
339 coda_vfs_stat.symlink++;
340
341 if (coda_isroot(dir_inode) && coda_iscontrol(name, len)) {
342 unlock_kernel();
343 return -EPERM;
344 }
345
346 symlen = strlen(symname);
347 if ( symlen > CODA_MAXPATHLEN ) {
348 unlock_kernel();
349 return -ENAMETOOLONG;
350 }
351
352 /*
353 * This entry is now negative. Since we do not create
354 * an inode for the entry we have to drop it.
355 */
356 d_drop(de);
357 error = venus_symlink(dir_inode->i_sb, coda_i2f(dir_inode), name, len,
358 symname, symlen);
359
360 /* mtime is no good anymore */
361 if ( !error )
362 coda_dir_update_mtime(dir_inode);
363
364 unlock_kernel();
365 return error;
366 }
367
368 /* destruction routines: unlink, rmdir */
369 int coda_unlink(struct inode *dir, struct dentry *de)
370 {
371 int error;
372 const char *name = de->d_name.name;
373 int len = de->d_name.len;
374
375 lock_kernel();
376 coda_vfs_stat.unlink++;
377
378 error = venus_remove(dir->i_sb, coda_i2f(dir), name, len);
379 if ( error ) {
380 unlock_kernel();
381 return error;
382 }
383
384 coda_dir_update_mtime(dir);
385 drop_nlink(de->d_inode);
386 unlock_kernel();
387 return 0;
388 }
389
390 int coda_rmdir(struct inode *dir, struct dentry *de)
391 {
392 const char *name = de->d_name.name;
393 int len = de->d_name.len;
394 int error;
395
396 lock_kernel();
397 coda_vfs_stat.rmdir++;
398
399 if (!d_unhashed(de)) {
400 unlock_kernel();
401 return -EBUSY;
402 }
403 error = venus_rmdir(dir->i_sb, coda_i2f(dir), name, len);
404
405 if ( error ) {
406 unlock_kernel();
407 return error;
408 }
409
410 coda_dir_drop_nlink(dir);
411 coda_dir_update_mtime(dir);
412 drop_nlink(de->d_inode);
413 d_delete(de);
414 unlock_kernel();
415 return 0;
416 }
417
418 /* rename */
419 static int coda_rename(struct inode *old_dir, struct dentry *old_dentry,
420 struct inode *new_dir, struct dentry *new_dentry)
421 {
422 const char *old_name = old_dentry->d_name.name;
423 const char *new_name = new_dentry->d_name.name;
424 int old_length = old_dentry->d_name.len;
425 int new_length = new_dentry->d_name.len;
426 int error;
427
428 lock_kernel();
429 coda_vfs_stat.rename++;
430
431 error = venus_rename(old_dir->i_sb, coda_i2f(old_dir),
432 coda_i2f(new_dir), old_length, new_length,
433 (const char *) old_name, (const char *)new_name);
434
435 if ( !error ) {
436 if ( new_dentry->d_inode ) {
437 if ( S_ISDIR(new_dentry->d_inode->i_mode) ) {
438 coda_dir_drop_nlink(old_dir);
439 coda_dir_inc_nlink(new_dir);
440 }
441 coda_dir_update_mtime(old_dir);
442 coda_dir_update_mtime(new_dir);
443 coda_flag_inode(new_dentry->d_inode, C_VATTR);
444 } else {
445 coda_flag_inode(old_dir, C_VATTR);
446 coda_flag_inode(new_dir, C_VATTR);
447 }
448 }
449 unlock_kernel();
450
451 return error;
452 }
453
454
455 /* file operations for directories */
456 int coda_readdir(struct file *coda_file, void *dirent, filldir_t filldir)
457 {
458 struct dentry *coda_dentry = coda_file->f_path.dentry;
459 struct coda_file_info *cfi;
460 struct file *host_file;
461 struct inode *host_inode;
462 int ret;
463
464 cfi = CODA_FTOC(coda_file);
465 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
466 host_file = cfi->cfi_container;
467
468 coda_vfs_stat.readdir++;
469
470 host_inode = host_file->f_path.dentry->d_inode;
471 mutex_lock(&host_inode->i_mutex);
472 host_file->f_pos = coda_file->f_pos;
473
474 if (!host_file->f_op->readdir) {
475 /* Venus: we must read Venus dirents from the file */
476 ret = coda_venus_readdir(host_file, filldir, dirent, coda_dentry);
477 } else {
478 /* potemkin case: we were handed a directory inode. */
479 /* Yuk, we can't call vfs_readdir because we are already
480 * holding the inode semaphore. */
481 ret = -ENOTDIR;
482 if (!host_file->f_op || !host_file->f_op->readdir)
483 goto out;
484
485 ret = -ENOENT;
486 if (!IS_DEADDIR(host_inode)) {
487 ret = host_file->f_op->readdir(host_file, dirent, filldir);
488 file_accessed(host_file);
489 }
490 }
491 out:
492 coda_file->f_pos = host_file->f_pos;
493 mutex_unlock(&host_inode->i_mutex);
494
495 return ret;
496 }
497
498 static inline unsigned int CDT2DT(unsigned char cdt)
499 {
500 unsigned int dt;
501
502 switch(cdt) {
503 case CDT_UNKNOWN: dt = DT_UNKNOWN; break;
504 case CDT_FIFO: dt = DT_FIFO; break;
505 case CDT_CHR: dt = DT_CHR; break;
506 case CDT_DIR: dt = DT_DIR; break;
507 case CDT_BLK: dt = DT_BLK; break;
508 case CDT_REG: dt = DT_REG; break;
509 case CDT_LNK: dt = DT_LNK; break;
510 case CDT_SOCK: dt = DT_SOCK; break;
511 case CDT_WHT: dt = DT_WHT; break;
512 default: dt = DT_UNKNOWN; break;
513 }
514 return dt;
515 }
516
517 /* support routines */
518 static int coda_venus_readdir(struct file *filp, filldir_t filldir,
519 void *dirent, struct dentry *dir)
520 {
521 int result = 0; /* # of entries returned */
522 struct venus_dirent *vdir;
523 unsigned long vdir_size =
524 (unsigned long)(&((struct venus_dirent *)0)->d_name);
525 unsigned int type;
526 struct qstr name;
527 ino_t ino;
528 int ret, i;
529
530 vdir = kmalloc(sizeof(*vdir), GFP_KERNEL);
531 if (!vdir) return -ENOMEM;
532
533 i = filp->f_pos;
534 switch(i) {
535 case 0:
536 ret = filldir(dirent, ".", 1, 0, dir->d_inode->i_ino, DT_DIR);
537 if (ret < 0) break;
538 result++;
539 filp->f_pos++;
540 /* fallthrough */
541 case 1:
542 ret = filldir(dirent, "..", 2, 1, dir->d_parent->d_inode->i_ino, DT_DIR);
543 if (ret < 0) break;
544 result++;
545 filp->f_pos++;
546 /* fallthrough */
547 default:
548 while (1) {
549 /* read entries from the directory file */
550 ret = kernel_read(filp, filp->f_pos - 2, (char *)vdir,
551 sizeof(*vdir));
552 if (ret < 0) {
553 printk("coda_venus_readdir: read dir failed %d\n", ret);
554 break;
555 }
556 if (ret == 0) break; /* end of directory file reached */
557
558 /* catch truncated reads */
559 if (ret < vdir_size || ret < vdir_size + vdir->d_namlen) {
560 printk("coda_venus_readdir: short read: %ld\n",
561 filp->f_path.dentry->d_inode->i_ino);
562 ret = -EBADF;
563 break;
564 }
565 /* validate whether the directory file actually makes sense */
566 if (vdir->d_reclen < vdir_size + vdir->d_namlen) {
567 printk("coda_venus_readdir: Invalid dir: %ld\n",
568 filp->f_path.dentry->d_inode->i_ino);
569 ret = -EBADF;
570 break;
571 }
572
573 name.len = vdir->d_namlen;
574 name.name = vdir->d_name;
575
576 /* Make sure we skip '.' and '..', we already got those */
577 if (name.name[0] == '.' && (name.len == 1 ||
578 (vdir->d_name[1] == '.' && name.len == 2)))
579 vdir->d_fileno = name.len = 0;
580
581 /* skip null entries */
582 if (vdir->d_fileno && name.len) {
583 /* try to look up this entry in the dcache, that way
584 * userspace doesn't have to worry about breaking
585 * getcwd by having mismatched inode numbers for
586 * internal volume mountpoints. */
587 ino = find_inode_number(dir, &name);
588 if (!ino) ino = vdir->d_fileno;
589
590 type = CDT2DT(vdir->d_type);
591 ret = filldir(dirent, name.name, name.len, filp->f_pos,
592 ino, type);
593 /* failure means no space for filling in this round */
594 if (ret < 0) break;
595 result++;
596 }
597 /* we'll always have progress because d_reclen is unsigned and
598 * we've already established it is non-zero. */
599 filp->f_pos += vdir->d_reclen;
600 }
601 }
602 kfree(vdir);
603 return result ? result : ret;
604 }
605
606 /* called when a cache lookup succeeds */
607 static int coda_dentry_revalidate(struct dentry *de, struct nameidata *nd)
608 {
609 struct inode *inode = de->d_inode;
610 struct coda_inode_info *cii;
611
612 if (!inode)
613 return 1;
614 lock_kernel();
615 if (coda_isroot(inode))
616 goto out;
617 if (is_bad_inode(inode))
618 goto bad;
619
620 cii = ITOC(de->d_inode);
621 if (!(cii->c_flags & (C_PURGE | C_FLUSH)))
622 goto out;
623
624 shrink_dcache_parent(de);
625
626 /* propagate for a flush */
627 if (cii->c_flags & C_FLUSH)
628 coda_flag_inode_children(inode, C_FLUSH);
629
630 if (atomic_read(&de->d_count) > 1)
631 /* pretend it's valid, but don't change the flags */
632 goto out;
633
634 /* clear the flags. */
635 cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);
636
637 bad:
638 unlock_kernel();
639 return 0;
640 out:
641 unlock_kernel();
642 return 1;
643 }
644
645 /*
646 * This is the callback from dput() when d_count is going to 0.
647 * We use this to unhash dentries with bad inodes.
648 */
649 static int coda_dentry_delete(struct dentry * dentry)
650 {
651 int flags;
652
653 if (!dentry->d_inode)
654 return 0;
655
656 flags = (ITOC(dentry->d_inode)->c_flags) & C_PURGE;
657 if (is_bad_inode(dentry->d_inode) || flags) {
658 return 1;
659 }
660 return 0;
661 }
662
663
664
665 /*
666 * This is called when we want to check if the inode has
667 * changed on the server. Coda makes this easy since the
668 * cache manager Venus issues a downcall to the kernel when this
669 * happens
670 */
671 int coda_revalidate_inode(struct dentry *dentry)
672 {
673 struct coda_vattr attr;
674 int error = 0;
675 int old_mode;
676 ino_t old_ino;
677 struct inode *inode = dentry->d_inode;
678 struct coda_inode_info *cii = ITOC(inode);
679
680 lock_kernel();
681 if ( !cii->c_flags )
682 goto ok;
683
684 if (cii->c_flags & (C_VATTR | C_PURGE | C_FLUSH)) {
685 error = venus_getattr(inode->i_sb, &(cii->c_fid), &attr);
686 if ( error )
687 goto return_bad;
688
689 /* this inode may be lost if:
690 - it's ino changed
691 - type changes must be permitted for repair and
692 missing mount points.
693 */
694 old_mode = inode->i_mode;
695 old_ino = inode->i_ino;
696 coda_vattr_to_iattr(inode, &attr);
697
698 if ((old_mode & S_IFMT) != (inode->i_mode & S_IFMT)) {
699 printk("Coda: inode %ld, fid %s changed type!\n",
700 inode->i_ino, coda_f2s(&(cii->c_fid)));
701 }
702
703 /* the following can happen when a local fid is replaced
704 with a global one, here we lose and declare the inode bad */
705 if (inode->i_ino != old_ino)
706 goto return_bad;
707
708 coda_flag_inode_children(inode, C_FLUSH);
709 cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);
710 }
711
712 ok:
713 unlock_kernel();
714 return 0;
715
716 return_bad:
717 unlock_kernel();
718 return -EIO;
719 }
Linux kernel - Deliverables
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