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md: fix up switching md arrays between read-only and read-write
[linux-2.6/mini2440.git] / fs / coda / dir.c
blob3d2580e00a3e272e0cfe04103c98466e2daa15e7
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 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, struct nameidata *nd)
141 {
142 int error = 0;
143
144 if (!mask)
145 return 0;
146
147 lock_kernel();
148
149 if (coda_cache_check(inode, mask))
150 goto out;
151
152 error = venus_access(inode->i_sb, coda_i2f(inode), mask);
153
154 if (!error)
155 coda_cache_enter(inode, mask);
156
157 out:
158 unlock_kernel();
159 return error;
160 }
161
162
163 static inline void coda_dir_update_mtime(struct inode *dir)
164 {
165 #ifdef REQUERY_VENUS_FOR_MTIME
166 /* invalidate the directory cnode's attributes so we refetch the
167 * attributes from venus next time the inode is referenced */
168 coda_flag_inode(dir, C_VATTR);
169 #else
170 /* optimistically we can also act as if our nose bleeds. The
171 * granularity of the mtime is coarse anyways so we might actually be
172 * right most of the time. Note: we only do this for directories. */
173 dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
174 #endif
175 }
176
177 /* we have to wrap inc_nlink/drop_nlink because sometimes userspace uses a
178 * trick to fool GNU find's optimizations. If we can't be sure of the link
179 * (because of volume mount points) we set i_nlink to 1 which forces find
180 * to consider every child as a possible directory. We should also never
181 * see an increment or decrement for deleted directories where i_nlink == 0 */
182 static inline void coda_dir_inc_nlink(struct inode *dir)
183 {
184 if (dir->i_nlink >= 2)
185 inc_nlink(dir);
186 }
187
188 static inline void coda_dir_drop_nlink(struct inode *dir)
189 {
190 if (dir->i_nlink > 2)
191 drop_nlink(dir);
192 }
193
194 /* creation routines: create, mknod, mkdir, link, symlink */
195 static int coda_create(struct inode *dir, struct dentry *de, int mode, struct nameidata *nd)
196 {
197 int error=0;
198 const char *name=de->d_name.name;
199 int length=de->d_name.len;
200 struct inode *inode;
201 struct CodaFid newfid;
202 struct coda_vattr attrs;
203
204 lock_kernel();
205
206 if (coda_isroot(dir) && coda_iscontrol(name, length)) {
207 unlock_kernel();
208 return -EPERM;
209 }
210
211 error = venus_create(dir->i_sb, coda_i2f(dir), name, length,
212 0, mode, &newfid, &attrs);
213
214 if ( error ) {
215 unlock_kernel();
216 d_drop(de);
217 return error;
218 }
219
220 inode = coda_iget(dir->i_sb, &newfid, &attrs);
221 if ( IS_ERR(inode) ) {
222 unlock_kernel();
223 d_drop(de);
224 return PTR_ERR(inode);
225 }
226
227 /* invalidate the directory cnode's attributes */
228 coda_dir_update_mtime(dir);
229 unlock_kernel();
230 d_instantiate(de, inode);
231 return 0;
232 }
233
234 static int coda_mkdir(struct inode *dir, struct dentry *de, int mode)
235 {
236 struct inode *inode;
237 struct coda_vattr attrs;
238 const char *name = de->d_name.name;
239 int len = de->d_name.len;
240 int error;
241 struct CodaFid newfid;
242
243 lock_kernel();
244
245 if (coda_isroot(dir) && coda_iscontrol(name, len)) {
246 unlock_kernel();
247 return -EPERM;
248 }
249
250 attrs.va_mode = mode;
251 error = venus_mkdir(dir->i_sb, coda_i2f(dir),
252 name, len, &newfid, &attrs);
253
254 if ( error ) {
255 unlock_kernel();
256 d_drop(de);
257 return error;
258 }
259
260 inode = coda_iget(dir->i_sb, &newfid, &attrs);
261 if ( IS_ERR(inode) ) {
262 unlock_kernel();
263 d_drop(de);
264 return PTR_ERR(inode);
265 }
266
267 /* invalidate the directory cnode's attributes */
268 coda_dir_inc_nlink(dir);
269 coda_dir_update_mtime(dir);
270 unlock_kernel();
271 d_instantiate(de, inode);
272 return 0;
273 }
274
275 /* try to make de an entry in dir_inodde linked to source_de */
276 static int coda_link(struct dentry *source_de, struct inode *dir_inode,
277 struct dentry *de)
278 {
279 struct inode *inode = source_de->d_inode;
280 const char * name = de->d_name.name;
281 int len = de->d_name.len;
282 int error;
283
284 lock_kernel();
285
286 if (coda_isroot(dir_inode) && coda_iscontrol(name, len)) {
287 unlock_kernel();
288 return -EPERM;
289 }
290
291 error = venus_link(dir_inode->i_sb, coda_i2f(inode),
292 coda_i2f(dir_inode), (const char *)name, len);
293
294 if (error) {
295 d_drop(de);
296 goto out;
297 }
298
299 coda_dir_update_mtime(dir_inode);
300 atomic_inc(&inode->i_count);
301 d_instantiate(de, inode);
302 inc_nlink(inode);
303
304 out:
305 unlock_kernel();
306 return(error);
307 }
308
309
310 static int coda_symlink(struct inode *dir_inode, struct dentry *de,
311 const char *symname)
312 {
313 const char *name = de->d_name.name;
314 int len = de->d_name.len;
315 int symlen;
316 int error = 0;
317
318 lock_kernel();
319
320 if (coda_isroot(dir_inode) && coda_iscontrol(name, len)) {
321 unlock_kernel();
322 return -EPERM;
323 }
324
325 symlen = strlen(symname);
326 if ( symlen > CODA_MAXPATHLEN ) {
327 unlock_kernel();
328 return -ENAMETOOLONG;
329 }
330
331 /*
332 * This entry is now negative. Since we do not create
333 * an inode for the entry we have to drop it.
334 */
335 d_drop(de);
336 error = venus_symlink(dir_inode->i_sb, coda_i2f(dir_inode), name, len,
337 symname, symlen);
338
339 /* mtime is no good anymore */
340 if ( !error )
341 coda_dir_update_mtime(dir_inode);
342
343 unlock_kernel();
344 return error;
345 }
346
347 /* destruction routines: unlink, rmdir */
348 static int coda_unlink(struct inode *dir, struct dentry *de)
349 {
350 int error;
351 const char *name = de->d_name.name;
352 int len = de->d_name.len;
353
354 lock_kernel();
355
356 error = venus_remove(dir->i_sb, coda_i2f(dir), name, len);
357 if ( error ) {
358 unlock_kernel();
359 return error;
360 }
361
362 coda_dir_update_mtime(dir);
363 drop_nlink(de->d_inode);
364 unlock_kernel();
365 return 0;
366 }
367
368 static int coda_rmdir(struct inode *dir, struct dentry *de)
369 {
370 const char *name = de->d_name.name;
371 int len = de->d_name.len;
372 int error;
373
374 lock_kernel();
375
376 error = venus_rmdir(dir->i_sb, coda_i2f(dir), name, len);
377 if (!error) {
378 /* VFS may delete the child */
379 if (de->d_inode)
380 de->d_inode->i_nlink = 0;
381
382 /* fix the link count of the parent */
383 coda_dir_drop_nlink(dir);
384 coda_dir_update_mtime(dir);
385 }
386 unlock_kernel();
387 return error;
388 }
389
390 /* rename */
391 static int coda_rename(struct inode *old_dir, struct dentry *old_dentry,
392 struct inode *new_dir, struct dentry *new_dentry)
393 {
394 const char *old_name = old_dentry->d_name.name;
395 const char *new_name = new_dentry->d_name.name;
396 int old_length = old_dentry->d_name.len;
397 int new_length = new_dentry->d_name.len;
398 int error;
399
400 lock_kernel();
401
402 error = venus_rename(old_dir->i_sb, coda_i2f(old_dir),
403 coda_i2f(new_dir), old_length, new_length,
404 (const char *) old_name, (const char *)new_name);
405
406 if ( !error ) {
407 if ( new_dentry->d_inode ) {
408 if ( S_ISDIR(new_dentry->d_inode->i_mode) ) {
409 coda_dir_drop_nlink(old_dir);
410 coda_dir_inc_nlink(new_dir);
411 }
412 coda_dir_update_mtime(old_dir);
413 coda_dir_update_mtime(new_dir);
414 coda_flag_inode(new_dentry->d_inode, C_VATTR);
415 } else {
416 coda_flag_inode(old_dir, C_VATTR);
417 coda_flag_inode(new_dir, C_VATTR);
418 }
419 }
420 unlock_kernel();
421
422 return error;
423 }
424
425
426 /* file operations for directories */
427 static int coda_readdir(struct file *coda_file, void *buf, filldir_t filldir)
428 {
429 struct coda_file_info *cfi;
430 struct file *host_file;
431 int ret;
432
433 cfi = CODA_FTOC(coda_file);
434 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
435 host_file = cfi->cfi_container;
436
437 if (!host_file->f_op)
438 return -ENOTDIR;
439
440 if (host_file->f_op->readdir)
441 {
442 /* potemkin case: we were handed a directory inode.
443 * We can't use vfs_readdir because we have to keep the file
444 * position in sync between the coda_file and the host_file.
445 * and as such we need grab the inode mutex. */
446 struct inode *host_inode = host_file->f_path.dentry->d_inode;
447
448 mutex_lock(&host_inode->i_mutex);
449 host_file->f_pos = coda_file->f_pos;
450
451 ret = -ENOENT;
452 if (!IS_DEADDIR(host_inode)) {
453 ret = host_file->f_op->readdir(host_file, buf, filldir);
454 file_accessed(host_file);
455 }
456
457 coda_file->f_pos = host_file->f_pos;
458 mutex_unlock(&host_inode->i_mutex);
459 }
460 else /* Venus: we must read Venus dirents from a file */
461 ret = coda_venus_readdir(coda_file, buf, filldir);
462
463 return ret;
464 }
465
466 static inline unsigned int CDT2DT(unsigned char cdt)
467 {
468 unsigned int dt;
469
470 switch(cdt) {
471 case CDT_UNKNOWN: dt = DT_UNKNOWN; break;
472 case CDT_FIFO: dt = DT_FIFO; break;
473 case CDT_CHR: dt = DT_CHR; break;
474 case CDT_DIR: dt = DT_DIR; break;
475 case CDT_BLK: dt = DT_BLK; break;
476 case CDT_REG: dt = DT_REG; break;
477 case CDT_LNK: dt = DT_LNK; break;
478 case CDT_SOCK: dt = DT_SOCK; break;
479 case CDT_WHT: dt = DT_WHT; break;
480 default: dt = DT_UNKNOWN; break;
481 }
482 return dt;
483 }
484
485 /* support routines */
486 static int coda_venus_readdir(struct file *coda_file, void *buf,
487 filldir_t filldir)
488 {
489 int result = 0; /* # of entries returned */
490 struct coda_file_info *cfi;
491 struct coda_inode_info *cii;
492 struct file *host_file;
493 struct dentry *de;
494 struct venus_dirent *vdir;
495 unsigned long vdir_size =
496 (unsigned long)(&((struct venus_dirent *)0)->d_name);
497 unsigned int type;
498 struct qstr name;
499 ino_t ino;
500 int ret;
501
502 cfi = CODA_FTOC(coda_file);
503 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
504 host_file = cfi->cfi_container;
505
506 de = coda_file->f_path.dentry;
507 cii = ITOC(de->d_inode);
508
509 vdir = kmalloc(sizeof(*vdir), GFP_KERNEL);
510 if (!vdir) return -ENOMEM;
511
512 if (coda_file->f_pos == 0) {
513 ret = filldir(buf, ".", 1, 0, de->d_inode->i_ino, DT_DIR);
514 if (ret < 0)
515 goto out;
516 result++;
517 coda_file->f_pos++;
518 }
519 if (coda_file->f_pos == 1) {
520 ret = filldir(buf, "..", 2, 1, de->d_parent->d_inode->i_ino, DT_DIR);
521 if (ret < 0)
522 goto out;
523 result++;
524 coda_file->f_pos++;
525 }
526 while (1) {
527 /* read entries from the directory file */
528 ret = kernel_read(host_file, coda_file->f_pos - 2, (char *)vdir,
529 sizeof(*vdir));
530 if (ret < 0) {
531 printk(KERN_ERR "coda readdir: read dir %s failed %d\n",
532 coda_f2s(&cii->c_fid), ret);
533 break;
534 }
535 if (ret == 0) break; /* end of directory file reached */
536
537 /* catch truncated reads */
538 if (ret < vdir_size || ret < vdir_size + vdir->d_namlen) {
539 printk(KERN_ERR "coda readdir: short read on %s\n",
540 coda_f2s(&cii->c_fid));
541 ret = -EBADF;
542 break;
543 }
544 /* validate whether the directory file actually makes sense */
545 if (vdir->d_reclen < vdir_size + vdir->d_namlen) {
546 printk(KERN_ERR "coda readdir: invalid dir %s\n",
547 coda_f2s(&cii->c_fid));
548 ret = -EBADF;
549 break;
550 }
551
552 name.len = vdir->d_namlen;
553 name.name = vdir->d_name;
554
555 /* Make sure we skip '.' and '..', we already got those */
556 if (name.name[0] == '.' && (name.len == 1 ||
557 (vdir->d_name[1] == '.' && name.len == 2)))
558 vdir->d_fileno = name.len = 0;
559
560 /* skip null entries */
561 if (vdir->d_fileno && name.len) {
562 /* try to look up this entry in the dcache, that way
563 * userspace doesn't have to worry about breaking
564 * getcwd by having mismatched inode numbers for
565 * internal volume mountpoints. */
566 ino = find_inode_number(de, &name);
567 if (!ino) ino = vdir->d_fileno;
568
569 type = CDT2DT(vdir->d_type);
570 ret = filldir(buf, name.name, name.len,
571 coda_file->f_pos, ino, type);
572 /* failure means no space for filling in this round */
573 if (ret < 0) break;
574 result++;
575 }
576 /* we'll always have progress because d_reclen is unsigned and
577 * we've already established it is non-zero. */
578 coda_file->f_pos += vdir->d_reclen;
579 }
580 out:
581 kfree(vdir);
582 return result ? result : ret;
583 }
584
585 /* called when a cache lookup succeeds */
586 static int coda_dentry_revalidate(struct dentry *de, struct nameidata *nd)
587 {
588 struct inode *inode = de->d_inode;
589 struct coda_inode_info *cii;
590
591 if (!inode)
592 return 1;
593 lock_kernel();
594 if (coda_isroot(inode))
595 goto out;
596 if (is_bad_inode(inode))
597 goto bad;
598
599 cii = ITOC(de->d_inode);
600 if (!(cii->c_flags & (C_PURGE | C_FLUSH)))
601 goto out;
602
603 shrink_dcache_parent(de);
604
605 /* propagate for a flush */
606 if (cii->c_flags & C_FLUSH)
607 coda_flag_inode_children(inode, C_FLUSH);
608
609 if (atomic_read(&de->d_count) > 1)
610 /* pretend it's valid, but don't change the flags */
611 goto out;
612
613 /* clear the flags. */
614 cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);
615
616 bad:
617 unlock_kernel();
618 return 0;
619 out:
620 unlock_kernel();
621 return 1;
622 }
623
624 /*
625 * This is the callback from dput() when d_count is going to 0.
626 * We use this to unhash dentries with bad inodes.
627 */
628 static int coda_dentry_delete(struct dentry * dentry)
629 {
630 int flags;
631
632 if (!dentry->d_inode)
633 return 0;
634
635 flags = (ITOC(dentry->d_inode)->c_flags) & C_PURGE;
636 if (is_bad_inode(dentry->d_inode) || flags) {
637 return 1;
638 }
639 return 0;
640 }
641
642
643
644 /*
645 * This is called when we want to check if the inode has
646 * changed on the server. Coda makes this easy since the
647 * cache manager Venus issues a downcall to the kernel when this
648 * happens
649 */
650 int coda_revalidate_inode(struct dentry *dentry)
651 {
652 struct coda_vattr attr;
653 int error = 0;
654 int old_mode;
655 ino_t old_ino;
656 struct inode *inode = dentry->d_inode;
657 struct coda_inode_info *cii = ITOC(inode);
658
659 lock_kernel();
660 if ( !cii->c_flags )
661 goto ok;
662
663 if (cii->c_flags & (C_VATTR | C_PURGE | C_FLUSH)) {
664 error = venus_getattr(inode->i_sb, &(cii->c_fid), &attr);
665 if ( error )
666 goto return_bad;
667
668 /* this inode may be lost if:
669 - it's ino changed
670 - type changes must be permitted for repair and
671 missing mount points.
672 */
673 old_mode = inode->i_mode;
674 old_ino = inode->i_ino;
675 coda_vattr_to_iattr(inode, &attr);
676
677 if ((old_mode & S_IFMT) != (inode->i_mode & S_IFMT)) {
678 printk("Coda: inode %ld, fid %s changed type!\n",
679 inode->i_ino, coda_f2s(&(cii->c_fid)));
680 }
681
682 /* the following can happen when a local fid is replaced
683 with a global one, here we lose and declare the inode bad */
684 if (inode->i_ino != old_ino)
685 goto return_bad;
686
687 coda_flag_inode_children(inode, C_FLUSH);
688 cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);
689 }
690
691 ok:
692 unlock_kernel();
693 return 0;
694
695 return_bad:
696 unlock_kernel();
697 return -EIO;
698 }
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