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coda: allow removal of busy directories
[GitHub/mt8127/android_kernel_alcatel_ttab.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 error = venus_rmdir(dir->i_sb, coda_i2f(dir), name, len);
400 if (!error) {
401 /* VFS may delete the child */
402 if (de->d_inode)
403 de->d_inode->i_nlink = 0;
404
405 /* fix the link count of the parent */
406 coda_dir_drop_nlink(dir);
407 coda_dir_update_mtime(dir);
408 }
409 unlock_kernel();
410 return error;
411 }
412
413 /* rename */
414 static int coda_rename(struct inode *old_dir, struct dentry *old_dentry,
415 struct inode *new_dir, struct dentry *new_dentry)
416 {
417 const char *old_name = old_dentry->d_name.name;
418 const char *new_name = new_dentry->d_name.name;
419 int old_length = old_dentry->d_name.len;
420 int new_length = new_dentry->d_name.len;
421 int error;
422
423 lock_kernel();
424 coda_vfs_stat.rename++;
425
426 error = venus_rename(old_dir->i_sb, coda_i2f(old_dir),
427 coda_i2f(new_dir), old_length, new_length,
428 (const char *) old_name, (const char *)new_name);
429
430 if ( !error ) {
431 if ( new_dentry->d_inode ) {
432 if ( S_ISDIR(new_dentry->d_inode->i_mode) ) {
433 coda_dir_drop_nlink(old_dir);
434 coda_dir_inc_nlink(new_dir);
435 }
436 coda_dir_update_mtime(old_dir);
437 coda_dir_update_mtime(new_dir);
438 coda_flag_inode(new_dentry->d_inode, C_VATTR);
439 } else {
440 coda_flag_inode(old_dir, C_VATTR);
441 coda_flag_inode(new_dir, C_VATTR);
442 }
443 }
444 unlock_kernel();
445
446 return error;
447 }
448
449
450 /* file operations for directories */
451 int coda_readdir(struct file *coda_file, void *dirent, filldir_t filldir)
452 {
453 struct dentry *coda_dentry = coda_file->f_path.dentry;
454 struct coda_file_info *cfi;
455 struct file *host_file;
456 struct inode *host_inode;
457 int ret;
458
459 cfi = CODA_FTOC(coda_file);
460 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
461 host_file = cfi->cfi_container;
462
463 coda_vfs_stat.readdir++;
464
465 host_inode = host_file->f_path.dentry->d_inode;
466 mutex_lock(&host_inode->i_mutex);
467 host_file->f_pos = coda_file->f_pos;
468
469 if (!host_file->f_op->readdir) {
470 /* Venus: we must read Venus dirents from the file */
471 ret = coda_venus_readdir(host_file, filldir, dirent, coda_dentry);
472 } else {
473 /* potemkin case: we were handed a directory inode. */
474 /* Yuk, we can't call vfs_readdir because we are already
475 * holding the inode semaphore. */
476 ret = -ENOTDIR;
477 if (!host_file->f_op || !host_file->f_op->readdir)
478 goto out;
479
480 ret = -ENOENT;
481 if (!IS_DEADDIR(host_inode)) {
482 ret = host_file->f_op->readdir(host_file, dirent, filldir);
483 file_accessed(host_file);
484 }
485 }
486 out:
487 coda_file->f_pos = host_file->f_pos;
488 mutex_unlock(&host_inode->i_mutex);
489
490 return ret;
491 }
492
493 static inline unsigned int CDT2DT(unsigned char cdt)
494 {
495 unsigned int dt;
496
497 switch(cdt) {
498 case CDT_UNKNOWN: dt = DT_UNKNOWN; break;
499 case CDT_FIFO: dt = DT_FIFO; break;
500 case CDT_CHR: dt = DT_CHR; break;
501 case CDT_DIR: dt = DT_DIR; break;
502 case CDT_BLK: dt = DT_BLK; break;
503 case CDT_REG: dt = DT_REG; break;
504 case CDT_LNK: dt = DT_LNK; break;
505 case CDT_SOCK: dt = DT_SOCK; break;
506 case CDT_WHT: dt = DT_WHT; break;
507 default: dt = DT_UNKNOWN; break;
508 }
509 return dt;
510 }
511
512 /* support routines */
513 static int coda_venus_readdir(struct file *filp, filldir_t filldir,
514 void *dirent, struct dentry *dir)
515 {
516 int result = 0; /* # of entries returned */
517 struct venus_dirent *vdir;
518 unsigned long vdir_size =
519 (unsigned long)(&((struct venus_dirent *)0)->d_name);
520 unsigned int type;
521 struct qstr name;
522 ino_t ino;
523 int ret, i;
524
525 vdir = kmalloc(sizeof(*vdir), GFP_KERNEL);
526 if (!vdir) return -ENOMEM;
527
528 i = filp->f_pos;
529 switch(i) {
530 case 0:
531 ret = filldir(dirent, ".", 1, 0, dir->d_inode->i_ino, DT_DIR);
532 if (ret < 0) break;
533 result++;
534 filp->f_pos++;
535 /* fallthrough */
536 case 1:
537 ret = filldir(dirent, "..", 2, 1, dir->d_parent->d_inode->i_ino, DT_DIR);
538 if (ret < 0) break;
539 result++;
540 filp->f_pos++;
541 /* fallthrough */
542 default:
543 while (1) {
544 /* read entries from the directory file */
545 ret = kernel_read(filp, filp->f_pos - 2, (char *)vdir,
546 sizeof(*vdir));
547 if (ret < 0) {
548 printk("coda_venus_readdir: read dir failed %d\n", ret);
549 break;
550 }
551 if (ret == 0) break; /* end of directory file reached */
552
553 /* catch truncated reads */
554 if (ret < vdir_size || ret < vdir_size + vdir->d_namlen) {
555 printk("coda_venus_readdir: short read: %ld\n",
556 filp->f_path.dentry->d_inode->i_ino);
557 ret = -EBADF;
558 break;
559 }
560 /* validate whether the directory file actually makes sense */
561 if (vdir->d_reclen < vdir_size + vdir->d_namlen) {
562 printk("coda_venus_readdir: Invalid dir: %ld\n",
563 filp->f_path.dentry->d_inode->i_ino);
564 ret = -EBADF;
565 break;
566 }
567
568 name.len = vdir->d_namlen;
569 name.name = vdir->d_name;
570
571 /* Make sure we skip '.' and '..', we already got those */
572 if (name.name[0] == '.' && (name.len == 1 ||
573 (vdir->d_name[1] == '.' && name.len == 2)))
574 vdir->d_fileno = name.len = 0;
575
576 /* skip null entries */
577 if (vdir->d_fileno && name.len) {
578 /* try to look up this entry in the dcache, that way
579 * userspace doesn't have to worry about breaking
580 * getcwd by having mismatched inode numbers for
581 * internal volume mountpoints. */
582 ino = find_inode_number(dir, &name);
583 if (!ino) ino = vdir->d_fileno;
584
585 type = CDT2DT(vdir->d_type);
586 ret = filldir(dirent, name.name, name.len, filp->f_pos,
587 ino, type);
588 /* failure means no space for filling in this round */
589 if (ret < 0) break;
590 result++;
591 }
592 /* we'll always have progress because d_reclen is unsigned and
593 * we've already established it is non-zero. */
594 filp->f_pos += vdir->d_reclen;
595 }
596 }
597 kfree(vdir);
598 return result ? result : ret;
599 }
600
601 /* called when a cache lookup succeeds */
602 static int coda_dentry_revalidate(struct dentry *de, struct nameidata *nd)
603 {
604 struct inode *inode = de->d_inode;
605 struct coda_inode_info *cii;
606
607 if (!inode)
608 return 1;
609 lock_kernel();
610 if (coda_isroot(inode))
611 goto out;
612 if (is_bad_inode(inode))
613 goto bad;
614
615 cii = ITOC(de->d_inode);
616 if (!(cii->c_flags & (C_PURGE | C_FLUSH)))
617 goto out;
618
619 shrink_dcache_parent(de);
620
621 /* propagate for a flush */
622 if (cii->c_flags & C_FLUSH)
623 coda_flag_inode_children(inode, C_FLUSH);
624
625 if (atomic_read(&de->d_count) > 1)
626 /* pretend it's valid, but don't change the flags */
627 goto out;
628
629 /* clear the flags. */
630 cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);
631
632 bad:
633 unlock_kernel();
634 return 0;
635 out:
636 unlock_kernel();
637 return 1;
638 }
639
640 /*
641 * This is the callback from dput() when d_count is going to 0.
642 * We use this to unhash dentries with bad inodes.
643 */
644 static int coda_dentry_delete(struct dentry * dentry)
645 {
646 int flags;
647
648 if (!dentry->d_inode)
649 return 0;
650
651 flags = (ITOC(dentry->d_inode)->c_flags) & C_PURGE;
652 if (is_bad_inode(dentry->d_inode) || flags) {
653 return 1;
654 }
655 return 0;
656 }
657
658
659
660 /*
661 * This is called when we want to check if the inode has
662 * changed on the server. Coda makes this easy since the
663 * cache manager Venus issues a downcall to the kernel when this
664 * happens
665 */
666 int coda_revalidate_inode(struct dentry *dentry)
667 {
668 struct coda_vattr attr;
669 int error = 0;
670 int old_mode;
671 ino_t old_ino;
672 struct inode *inode = dentry->d_inode;
673 struct coda_inode_info *cii = ITOC(inode);
674
675 lock_kernel();
676 if ( !cii->c_flags )
677 goto ok;
678
679 if (cii->c_flags & (C_VATTR | C_PURGE | C_FLUSH)) {
680 error = venus_getattr(inode->i_sb, &(cii->c_fid), &attr);
681 if ( error )
682 goto return_bad;
683
684 /* this inode may be lost if:
685 - it's ino changed
686 - type changes must be permitted for repair and
687 missing mount points.
688 */
689 old_mode = inode->i_mode;
690 old_ino = inode->i_ino;
691 coda_vattr_to_iattr(inode, &attr);
692
693 if ((old_mode & S_IFMT) != (inode->i_mode & S_IFMT)) {
694 printk("Coda: inode %ld, fid %s changed type!\n",
695 inode->i_ino, coda_f2s(&(cii->c_fid)));
696 }
697
698 /* the following can happen when a local fid is replaced
699 with a global one, here we lose and declare the inode bad */
700 if (inode->i_ino != old_ino)
701 goto return_bad;
702
703 coda_flag_inode_children(inode, C_FLUSH);
704 cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);
705 }
706
707 ok:
708 unlock_kernel();
709 return 0;
710
711 return_bad:
712 unlock_kernel();
713 return -EIO;
714 }
kernel source for telekom puls (alcatel/mediatek)