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Merge branch 'fix/asoc' into for-linus
[linux-2.6/next.git] / fs / coda / dir.c
blob5d8b35539601b819389057b9114dd49a75828597
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/spinlock.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 error = venus_lookup(dir->i_sb, coda_i2f(dir), name, length,
120 &type, &resfid);
121 if (!error)
122 error = coda_cnode_make(&inode, &resfid, dir->i_sb);
123
124 if (error && error != -ENOENT)
125 return ERR_PTR(error);
126
127 exit:
128 entry->d_op = &coda_dentry_operations;
129
130 if (inode && (type & CODA_NOCACHE))
131 coda_flag_inode(inode, C_VATTR | C_PURGE);
132
133 return d_splice_alias(inode, entry);
134 }
135
136
137 int coda_permission(struct inode *inode, int mask)
138 {
139 int error;
140
141 mask &= MAY_READ | MAY_WRITE | MAY_EXEC;
142
143 if (!mask)
144 return 0;
145
146 if ((mask & MAY_EXEC) && !execute_ok(inode))
147 return -EACCES;
148
149 if (coda_cache_check(inode, mask))
150 return 0;
151
152 error = venus_access(inode->i_sb, coda_i2f(inode), mask);
153
154 if (!error)
155 coda_cache_enter(inode, mask);
156
157 return error;
158 }
159
160
161 static inline void coda_dir_update_mtime(struct inode *dir)
162 {
163 #ifdef REQUERY_VENUS_FOR_MTIME
164 /* invalidate the directory cnode's attributes so we refetch the
165 * attributes from venus next time the inode is referenced */
166 coda_flag_inode(dir, C_VATTR);
167 #else
168 /* optimistically we can also act as if our nose bleeds. The
169 * granularity of the mtime is coarse anyways so we might actually be
170 * right most of the time. Note: we only do this for directories. */
171 dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
172 #endif
173 }
174
175 /* we have to wrap inc_nlink/drop_nlink because sometimes userspace uses a
176 * trick to fool GNU find's optimizations. If we can't be sure of the link
177 * (because of volume mount points) we set i_nlink to 1 which forces find
178 * to consider every child as a possible directory. We should also never
179 * see an increment or decrement for deleted directories where i_nlink == 0 */
180 static inline void coda_dir_inc_nlink(struct inode *dir)
181 {
182 if (dir->i_nlink >= 2)
183 inc_nlink(dir);
184 }
185
186 static inline void coda_dir_drop_nlink(struct inode *dir)
187 {
188 if (dir->i_nlink > 2)
189 drop_nlink(dir);
190 }
191
192 /* creation routines: create, mknod, mkdir, link, symlink */
193 static int coda_create(struct inode *dir, struct dentry *de, int mode, struct nameidata *nd)
194 {
195 int error;
196 const char *name=de->d_name.name;
197 int length=de->d_name.len;
198 struct inode *inode;
199 struct CodaFid newfid;
200 struct coda_vattr attrs;
201
202 if (coda_isroot(dir) && coda_iscontrol(name, length))
203 return -EPERM;
204
205 error = venus_create(dir->i_sb, coda_i2f(dir), name, length,
206 0, mode, &newfid, &attrs);
207 if (error)
208 goto err_out;
209
210 inode = coda_iget(dir->i_sb, &newfid, &attrs);
211 if (IS_ERR(inode)) {
212 error = PTR_ERR(inode);
213 goto err_out;
214 }
215
216 /* invalidate the directory cnode's attributes */
217 coda_dir_update_mtime(dir);
218 d_instantiate(de, inode);
219 return 0;
220 err_out:
221 d_drop(de);
222 return error;
223 }
224
225 static int coda_mkdir(struct inode *dir, struct dentry *de, int mode)
226 {
227 struct inode *inode;
228 struct coda_vattr attrs;
229 const char *name = de->d_name.name;
230 int len = de->d_name.len;
231 int error;
232 struct CodaFid newfid;
233
234 if (coda_isroot(dir) && coda_iscontrol(name, len))
235 return -EPERM;
236
237 attrs.va_mode = mode;
238 error = venus_mkdir(dir->i_sb, coda_i2f(dir),
239 name, len, &newfid, &attrs);
240 if (error)
241 goto err_out;
242
243 inode = coda_iget(dir->i_sb, &newfid, &attrs);
244 if (IS_ERR(inode)) {
245 error = PTR_ERR(inode);
246 goto err_out;
247 }
248
249 /* invalidate the directory cnode's attributes */
250 coda_dir_inc_nlink(dir);
251 coda_dir_update_mtime(dir);
252 d_instantiate(de, inode);
253 return 0;
254 err_out:
255 d_drop(de);
256 return error;
257 }
258
259 /* try to make de an entry in dir_inodde linked to source_de */
260 static int coda_link(struct dentry *source_de, struct inode *dir_inode,
261 struct dentry *de)
262 {
263 struct inode *inode = source_de->d_inode;
264 const char * name = de->d_name.name;
265 int len = de->d_name.len;
266 int error;
267
268 if (coda_isroot(dir_inode) && coda_iscontrol(name, len))
269 return -EPERM;
270
271 error = venus_link(dir_inode->i_sb, coda_i2f(inode),
272 coda_i2f(dir_inode), (const char *)name, len);
273 if (error) {
274 d_drop(de);
275 return error;
276 }
277
278 coda_dir_update_mtime(dir_inode);
279 ihold(inode);
280 d_instantiate(de, inode);
281 inc_nlink(inode);
282 return 0;
283 }
284
285
286 static int coda_symlink(struct inode *dir_inode, struct dentry *de,
287 const char *symname)
288 {
289 const char *name = de->d_name.name;
290 int len = de->d_name.len;
291 int symlen;
292 int error;
293
294 if (coda_isroot(dir_inode) && coda_iscontrol(name, len))
295 return -EPERM;
296
297 symlen = strlen(symname);
298 if (symlen > CODA_MAXPATHLEN)
299 return -ENAMETOOLONG;
300
301 /*
302 * This entry is now negative. Since we do not create
303 * an inode for the entry we have to drop it.
304 */
305 d_drop(de);
306 error = venus_symlink(dir_inode->i_sb, coda_i2f(dir_inode), name, len,
307 symname, symlen);
308
309 /* mtime is no good anymore */
310 if (!error)
311 coda_dir_update_mtime(dir_inode);
312
313 return error;
314 }
315
316 /* destruction routines: unlink, rmdir */
317 static int coda_unlink(struct inode *dir, struct dentry *de)
318 {
319 int error;
320 const char *name = de->d_name.name;
321 int len = de->d_name.len;
322
323 error = venus_remove(dir->i_sb, coda_i2f(dir), name, len);
324 if (error)
325 return error;
326
327 coda_dir_update_mtime(dir);
328 drop_nlink(de->d_inode);
329 return 0;
330 }
331
332 static int coda_rmdir(struct inode *dir, struct dentry *de)
333 {
334 const char *name = de->d_name.name;
335 int len = de->d_name.len;
336 int error;
337
338 error = venus_rmdir(dir->i_sb, coda_i2f(dir), name, len);
339 if (!error) {
340 /* VFS may delete the child */
341 if (de->d_inode)
342 de->d_inode->i_nlink = 0;
343
344 /* fix the link count of the parent */
345 coda_dir_drop_nlink(dir);
346 coda_dir_update_mtime(dir);
347 }
348 return error;
349 }
350
351 /* rename */
352 static int coda_rename(struct inode *old_dir, struct dentry *old_dentry,
353 struct inode *new_dir, struct dentry *new_dentry)
354 {
355 const char *old_name = old_dentry->d_name.name;
356 const char *new_name = new_dentry->d_name.name;
357 int old_length = old_dentry->d_name.len;
358 int new_length = new_dentry->d_name.len;
359 int error;
360
361 error = venus_rename(old_dir->i_sb, coda_i2f(old_dir),
362 coda_i2f(new_dir), old_length, new_length,
363 (const char *) old_name, (const char *)new_name);
364 if (!error) {
365 if (new_dentry->d_inode) {
366 if (S_ISDIR(new_dentry->d_inode->i_mode)) {
367 coda_dir_drop_nlink(old_dir);
368 coda_dir_inc_nlink(new_dir);
369 }
370 coda_dir_update_mtime(old_dir);
371 coda_dir_update_mtime(new_dir);
372 coda_flag_inode(new_dentry->d_inode, C_VATTR);
373 } else {
374 coda_flag_inode(old_dir, C_VATTR);
375 coda_flag_inode(new_dir, C_VATTR);
376 }
377 }
378 return error;
379 }
380
381
382 /* file operations for directories */
383 static int coda_readdir(struct file *coda_file, void *buf, filldir_t filldir)
384 {
385 struct coda_file_info *cfi;
386 struct file *host_file;
387 int ret;
388
389 cfi = CODA_FTOC(coda_file);
390 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
391 host_file = cfi->cfi_container;
392
393 if (!host_file->f_op)
394 return -ENOTDIR;
395
396 if (host_file->f_op->readdir)
397 {
398 /* potemkin case: we were handed a directory inode.
399 * We can't use vfs_readdir because we have to keep the file
400 * position in sync between the coda_file and the host_file.
401 * and as such we need grab the inode mutex. */
402 struct inode *host_inode = host_file->f_path.dentry->d_inode;
403
404 mutex_lock(&host_inode->i_mutex);
405 host_file->f_pos = coda_file->f_pos;
406
407 ret = -ENOENT;
408 if (!IS_DEADDIR(host_inode)) {
409 ret = host_file->f_op->readdir(host_file, buf, filldir);
410 file_accessed(host_file);
411 }
412
413 coda_file->f_pos = host_file->f_pos;
414 mutex_unlock(&host_inode->i_mutex);
415 }
416 else /* Venus: we must read Venus dirents from a file */
417 ret = coda_venus_readdir(coda_file, buf, filldir);
418
419 return ret;
420 }
421
422 static inline unsigned int CDT2DT(unsigned char cdt)
423 {
424 unsigned int dt;
425
426 switch(cdt) {
427 case CDT_UNKNOWN: dt = DT_UNKNOWN; break;
428 case CDT_FIFO: dt = DT_FIFO; break;
429 case CDT_CHR: dt = DT_CHR; break;
430 case CDT_DIR: dt = DT_DIR; break;
431 case CDT_BLK: dt = DT_BLK; break;
432 case CDT_REG: dt = DT_REG; break;
433 case CDT_LNK: dt = DT_LNK; break;
434 case CDT_SOCK: dt = DT_SOCK; break;
435 case CDT_WHT: dt = DT_WHT; break;
436 default: dt = DT_UNKNOWN; break;
437 }
438 return dt;
439 }
440
441 /* support routines */
442 static int coda_venus_readdir(struct file *coda_file, void *buf,
443 filldir_t filldir)
444 {
445 int result = 0; /* # of entries returned */
446 struct coda_file_info *cfi;
447 struct coda_inode_info *cii;
448 struct file *host_file;
449 struct dentry *de;
450 struct venus_dirent *vdir;
451 unsigned long vdir_size =
452 (unsigned long)(&((struct venus_dirent *)0)->d_name);
453 unsigned int type;
454 struct qstr name;
455 ino_t ino;
456 int ret;
457
458 cfi = CODA_FTOC(coda_file);
459 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
460 host_file = cfi->cfi_container;
461
462 de = coda_file->f_path.dentry;
463 cii = ITOC(de->d_inode);
464
465 vdir = kmalloc(sizeof(*vdir), GFP_KERNEL);
466 if (!vdir) return -ENOMEM;
467
468 if (coda_file->f_pos == 0) {
469 ret = filldir(buf, ".", 1, 0, de->d_inode->i_ino, DT_DIR);
470 if (ret < 0)
471 goto out;
472 result++;
473 coda_file->f_pos++;
474 }
475 if (coda_file->f_pos == 1) {
476 ret = filldir(buf, "..", 2, 1, de->d_parent->d_inode->i_ino, DT_DIR);
477 if (ret < 0)
478 goto out;
479 result++;
480 coda_file->f_pos++;
481 }
482 while (1) {
483 /* read entries from the directory file */
484 ret = kernel_read(host_file, coda_file->f_pos - 2, (char *)vdir,
485 sizeof(*vdir));
486 if (ret < 0) {
487 printk(KERN_ERR "coda readdir: read dir %s failed %d\n",
488 coda_f2s(&cii->c_fid), ret);
489 break;
490 }
491 if (ret == 0) break; /* end of directory file reached */
492
493 /* catch truncated reads */
494 if (ret < vdir_size || ret < vdir_size + vdir->d_namlen) {
495 printk(KERN_ERR "coda readdir: short read on %s\n",
496 coda_f2s(&cii->c_fid));
497 ret = -EBADF;
498 break;
499 }
500 /* validate whether the directory file actually makes sense */
501 if (vdir->d_reclen < vdir_size + vdir->d_namlen) {
502 printk(KERN_ERR "coda readdir: invalid dir %s\n",
503 coda_f2s(&cii->c_fid));
504 ret = -EBADF;
505 break;
506 }
507
508 name.len = vdir->d_namlen;
509 name.name = vdir->d_name;
510
511 /* Make sure we skip '.' and '..', we already got those */
512 if (name.name[0] == '.' && (name.len == 1 ||
513 (vdir->d_name[1] == '.' && name.len == 2)))
514 vdir->d_fileno = name.len = 0;
515
516 /* skip null entries */
517 if (vdir->d_fileno && name.len) {
518 /* try to look up this entry in the dcache, that way
519 * userspace doesn't have to worry about breaking
520 * getcwd by having mismatched inode numbers for
521 * internal volume mountpoints. */
522 ino = find_inode_number(de, &name);
523 if (!ino) ino = vdir->d_fileno;
524
525 type = CDT2DT(vdir->d_type);
526 ret = filldir(buf, name.name, name.len,
527 coda_file->f_pos, ino, type);
528 /* failure means no space for filling in this round */
529 if (ret < 0) break;
530 result++;
531 }
532 /* we'll always have progress because d_reclen is unsigned and
533 * we've already established it is non-zero. */
534 coda_file->f_pos += vdir->d_reclen;
535 }
536 out:
537 kfree(vdir);
538 return result ? result : ret;
539 }
540
541 /* called when a cache lookup succeeds */
542 static int coda_dentry_revalidate(struct dentry *de, struct nameidata *nd)
543 {
544 struct inode *inode = de->d_inode;
545 struct coda_inode_info *cii;
546
547 if (!inode || coda_isroot(inode))
548 goto out;
549 if (is_bad_inode(inode))
550 goto bad;
551
552 cii = ITOC(de->d_inode);
553 if (!(cii->c_flags & (C_PURGE | C_FLUSH)))
554 goto out;
555
556 shrink_dcache_parent(de);
557
558 /* propagate for a flush */
559 if (cii->c_flags & C_FLUSH)
560 coda_flag_inode_children(inode, C_FLUSH);
561
562 if (atomic_read(&de->d_count) > 1)
563 /* pretend it's valid, but don't change the flags */
564 goto out;
565
566 /* clear the flags. */
567 spin_lock(&cii->c_lock);
568 cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);
569 spin_unlock(&cii->c_lock);
570 bad:
571 return 0;
572 out:
573 return 1;
574 }
575
576 /*
577 * This is the callback from dput() when d_count is going to 0.
578 * We use this to unhash dentries with bad inodes.
579 */
580 static int coda_dentry_delete(struct dentry * dentry)
581 {
582 int flags;
583
584 if (!dentry->d_inode)
585 return 0;
586
587 flags = (ITOC(dentry->d_inode)->c_flags) & C_PURGE;
588 if (is_bad_inode(dentry->d_inode) || flags) {
589 return 1;
590 }
591 return 0;
592 }
593
594
595
596 /*
597 * This is called when we want to check if the inode has
598 * changed on the server. Coda makes this easy since the
599 * cache manager Venus issues a downcall to the kernel when this
600 * happens
601 */
602 int coda_revalidate_inode(struct dentry *dentry)
603 {
604 struct coda_vattr attr;
605 int error;
606 int old_mode;
607 ino_t old_ino;
608 struct inode *inode = dentry->d_inode;
609 struct coda_inode_info *cii = ITOC(inode);
610
611 if (!cii->c_flags)
612 return 0;
613
614 if (cii->c_flags & (C_VATTR | C_PURGE | C_FLUSH)) {
615 error = venus_getattr(inode->i_sb, &(cii->c_fid), &attr);
616 if (error)
617 return -EIO;
618
619 /* this inode may be lost if:
620 - it's ino changed
621 - type changes must be permitted for repair and
622 missing mount points.
623 */
624 old_mode = inode->i_mode;
625 old_ino = inode->i_ino;
626 coda_vattr_to_iattr(inode, &attr);
627
628 if ((old_mode & S_IFMT) != (inode->i_mode & S_IFMT)) {
629 printk("Coda: inode %ld, fid %s changed type!\n",
630 inode->i_ino, coda_f2s(&(cii->c_fid)));
631 }
632
633 /* the following can happen when a local fid is replaced
634 with a global one, here we lose and declare the inode bad */
635 if (inode->i_ino != old_ino)
636 return -EIO;
637
638 coda_flag_inode_children(inode, C_FLUSH);
639
640 spin_lock(&cii->c_lock);
641 cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);
642 spin_unlock(&cii->c_lock);
643 }
644 return 0;
645 }
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