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Linux 3.8-rc7
[cris-mirror.git] / fs / coda / dir.c
blob49fe52d256009729ae9c9ec5cfd1b684255219f3
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 #include <linux/namei.h>
22
23 #include <asm/uaccess.h>
24
25 #include <linux/coda.h>
26 #include <linux/coda_psdev.h>
27 #include "coda_linux.h"
28 #include "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, umode_t mode, bool excl);
34 static struct dentry *coda_lookup(struct inode *dir, struct dentry *target, unsigned int flags);
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, umode_t 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, unsigned int flags);
50 static int coda_dentry_delete(const 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 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, unsigned int flags)
98 {
99 struct super_block *sb = dir->i_sb;
100 const char *name = entry->d_name.name;
101 size_t length = entry->d_name.len;
102 struct inode *inode;
103 int type = 0;
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 inode = coda_cnode_makectl(sb);
114 type = CODA_NOCACHE;
115 } else {
116 struct CodaFid fid = { { 0, } };
117 int error = venus_lookup(sb, coda_i2f(dir), name, length,
118 &type, &fid);
119 inode = !error ? coda_cnode_make(&fid, sb) : ERR_PTR(error);
120 }
121
122 if (!IS_ERR(inode) && (type & CODA_NOCACHE))
123 coda_flag_inode(inode, C_VATTR | C_PURGE);
124
125 if (inode == ERR_PTR(-ENOENT))
126 inode = NULL;
127
128 return d_splice_alias(inode, entry);
129 }
130
131
132 int coda_permission(struct inode *inode, int mask)
133 {
134 int error;
135
136 if (mask & MAY_NOT_BLOCK)
137 return -ECHILD;
138
139 mask &= MAY_READ | MAY_WRITE | MAY_EXEC;
140
141 if (!mask)
142 return 0;
143
144 if ((mask & MAY_EXEC) && !execute_ok(inode))
145 return -EACCES;
146
147 if (coda_cache_check(inode, mask))
148 return 0;
149
150 error = venus_access(inode->i_sb, coda_i2f(inode), mask);
151
152 if (!error)
153 coda_cache_enter(inode, mask);
154
155 return error;
156 }
157
158
159 static inline void coda_dir_update_mtime(struct inode *dir)
160 {
161 #ifdef REQUERY_VENUS_FOR_MTIME
162 /* invalidate the directory cnode's attributes so we refetch the
163 * attributes from venus next time the inode is referenced */
164 coda_flag_inode(dir, C_VATTR);
165 #else
166 /* optimistically we can also act as if our nose bleeds. The
167 * granularity of the mtime is coarse anyways so we might actually be
168 * right most of the time. Note: we only do this for directories. */
169 dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
170 #endif
171 }
172
173 /* we have to wrap inc_nlink/drop_nlink because sometimes userspace uses a
174 * trick to fool GNU find's optimizations. If we can't be sure of the link
175 * (because of volume mount points) we set i_nlink to 1 which forces find
176 * to consider every child as a possible directory. We should also never
177 * see an increment or decrement for deleted directories where i_nlink == 0 */
178 static inline void coda_dir_inc_nlink(struct inode *dir)
179 {
180 if (dir->i_nlink >= 2)
181 inc_nlink(dir);
182 }
183
184 static inline void coda_dir_drop_nlink(struct inode *dir)
185 {
186 if (dir->i_nlink > 2)
187 drop_nlink(dir);
188 }
189
190 /* creation routines: create, mknod, mkdir, link, symlink */
191 static int coda_create(struct inode *dir, struct dentry *de, umode_t mode, bool excl)
192 {
193 int error;
194 const char *name=de->d_name.name;
195 int length=de->d_name.len;
196 struct inode *inode;
197 struct CodaFid newfid;
198 struct coda_vattr attrs;
199
200 if (coda_isroot(dir) && coda_iscontrol(name, length))
201 return -EPERM;
202
203 error = venus_create(dir->i_sb, coda_i2f(dir), name, length,
204 0, mode, &newfid, &attrs);
205 if (error)
206 goto err_out;
207
208 inode = coda_iget(dir->i_sb, &newfid, &attrs);
209 if (IS_ERR(inode)) {
210 error = PTR_ERR(inode);
211 goto err_out;
212 }
213
214 /* invalidate the directory cnode's attributes */
215 coda_dir_update_mtime(dir);
216 d_instantiate(de, inode);
217 return 0;
218 err_out:
219 d_drop(de);
220 return error;
221 }
222
223 static int coda_mkdir(struct inode *dir, struct dentry *de, umode_t mode)
224 {
225 struct inode *inode;
226 struct coda_vattr attrs;
227 const char *name = de->d_name.name;
228 int len = de->d_name.len;
229 int error;
230 struct CodaFid newfid;
231
232 if (coda_isroot(dir) && coda_iscontrol(name, len))
233 return -EPERM;
234
235 attrs.va_mode = mode;
236 error = venus_mkdir(dir->i_sb, coda_i2f(dir),
237 name, len, &newfid, &attrs);
238 if (error)
239 goto err_out;
240
241 inode = coda_iget(dir->i_sb, &newfid, &attrs);
242 if (IS_ERR(inode)) {
243 error = PTR_ERR(inode);
244 goto err_out;
245 }
246
247 /* invalidate the directory cnode's attributes */
248 coda_dir_inc_nlink(dir);
249 coda_dir_update_mtime(dir);
250 d_instantiate(de, inode);
251 return 0;
252 err_out:
253 d_drop(de);
254 return error;
255 }
256
257 /* try to make de an entry in dir_inodde linked to source_de */
258 static int coda_link(struct dentry *source_de, struct inode *dir_inode,
259 struct dentry *de)
260 {
261 struct inode *inode = source_de->d_inode;
262 const char * name = de->d_name.name;
263 int len = de->d_name.len;
264 int error;
265
266 if (coda_isroot(dir_inode) && coda_iscontrol(name, len))
267 return -EPERM;
268
269 error = venus_link(dir_inode->i_sb, coda_i2f(inode),
270 coda_i2f(dir_inode), (const char *)name, len);
271 if (error) {
272 d_drop(de);
273 return error;
274 }
275
276 coda_dir_update_mtime(dir_inode);
277 ihold(inode);
278 d_instantiate(de, inode);
279 inc_nlink(inode);
280 return 0;
281 }
282
283
284 static int coda_symlink(struct inode *dir_inode, struct dentry *de,
285 const char *symname)
286 {
287 const char *name = de->d_name.name;
288 int len = de->d_name.len;
289 int symlen;
290 int error;
291
292 if (coda_isroot(dir_inode) && coda_iscontrol(name, len))
293 return -EPERM;
294
295 symlen = strlen(symname);
296 if (symlen > CODA_MAXPATHLEN)
297 return -ENAMETOOLONG;
298
299 /*
300 * This entry is now negative. Since we do not create
301 * an inode for the entry we have to drop it.
302 */
303 d_drop(de);
304 error = venus_symlink(dir_inode->i_sb, coda_i2f(dir_inode), name, len,
305 symname, symlen);
306
307 /* mtime is no good anymore */
308 if (!error)
309 coda_dir_update_mtime(dir_inode);
310
311 return error;
312 }
313
314 /* destruction routines: unlink, rmdir */
315 static int coda_unlink(struct inode *dir, struct dentry *de)
316 {
317 int error;
318 const char *name = de->d_name.name;
319 int len = de->d_name.len;
320
321 error = venus_remove(dir->i_sb, coda_i2f(dir), name, len);
322 if (error)
323 return error;
324
325 coda_dir_update_mtime(dir);
326 drop_nlink(de->d_inode);
327 return 0;
328 }
329
330 static int coda_rmdir(struct inode *dir, struct dentry *de)
331 {
332 const char *name = de->d_name.name;
333 int len = de->d_name.len;
334 int error;
335
336 error = venus_rmdir(dir->i_sb, coda_i2f(dir), name, len);
337 if (!error) {
338 /* VFS may delete the child */
339 if (de->d_inode)
340 clear_nlink(de->d_inode);
341
342 /* fix the link count of the parent */
343 coda_dir_drop_nlink(dir);
344 coda_dir_update_mtime(dir);
345 }
346 return error;
347 }
348
349 /* rename */
350 static int coda_rename(struct inode *old_dir, struct dentry *old_dentry,
351 struct inode *new_dir, struct dentry *new_dentry)
352 {
353 const char *old_name = old_dentry->d_name.name;
354 const char *new_name = new_dentry->d_name.name;
355 int old_length = old_dentry->d_name.len;
356 int new_length = new_dentry->d_name.len;
357 int error;
358
359 error = venus_rename(old_dir->i_sb, coda_i2f(old_dir),
360 coda_i2f(new_dir), old_length, new_length,
361 (const char *) old_name, (const char *)new_name);
362 if (!error) {
363 if (new_dentry->d_inode) {
364 if (S_ISDIR(new_dentry->d_inode->i_mode)) {
365 coda_dir_drop_nlink(old_dir);
366 coda_dir_inc_nlink(new_dir);
367 }
368 coda_dir_update_mtime(old_dir);
369 coda_dir_update_mtime(new_dir);
370 coda_flag_inode(new_dentry->d_inode, C_VATTR);
371 } else {
372 coda_flag_inode(old_dir, C_VATTR);
373 coda_flag_inode(new_dir, C_VATTR);
374 }
375 }
376 return error;
377 }
378
379
380 /* file operations for directories */
381 static int coda_readdir(struct file *coda_file, void *buf, filldir_t filldir)
382 {
383 struct coda_file_info *cfi;
384 struct file *host_file;
385 int ret;
386
387 cfi = CODA_FTOC(coda_file);
388 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
389 host_file = cfi->cfi_container;
390
391 if (!host_file->f_op)
392 return -ENOTDIR;
393
394 if (host_file->f_op->readdir)
395 {
396 /* potemkin case: we were handed a directory inode.
397 * We can't use vfs_readdir because we have to keep the file
398 * position in sync between the coda_file and the host_file.
399 * and as such we need grab the inode mutex. */
400 struct inode *host_inode = host_file->f_path.dentry->d_inode;
401
402 mutex_lock(&host_inode->i_mutex);
403 host_file->f_pos = coda_file->f_pos;
404
405 ret = -ENOENT;
406 if (!IS_DEADDIR(host_inode)) {
407 ret = host_file->f_op->readdir(host_file, buf, filldir);
408 file_accessed(host_file);
409 }
410
411 coda_file->f_pos = host_file->f_pos;
412 mutex_unlock(&host_inode->i_mutex);
413 }
414 else /* Venus: we must read Venus dirents from a file */
415 ret = coda_venus_readdir(coda_file, buf, filldir);
416
417 return ret;
418 }
419
420 static inline unsigned int CDT2DT(unsigned char cdt)
421 {
422 unsigned int dt;
423
424 switch(cdt) {
425 case CDT_UNKNOWN: dt = DT_UNKNOWN; break;
426 case CDT_FIFO: dt = DT_FIFO; break;
427 case CDT_CHR: dt = DT_CHR; break;
428 case CDT_DIR: dt = DT_DIR; break;
429 case CDT_BLK: dt = DT_BLK; break;
430 case CDT_REG: dt = DT_REG; break;
431 case CDT_LNK: dt = DT_LNK; break;
432 case CDT_SOCK: dt = DT_SOCK; break;
433 case CDT_WHT: dt = DT_WHT; break;
434 default: dt = DT_UNKNOWN; break;
435 }
436 return dt;
437 }
438
439 /* support routines */
440 static int coda_venus_readdir(struct file *coda_file, void *buf,
441 filldir_t filldir)
442 {
443 int result = 0; /* # of entries returned */
444 struct coda_file_info *cfi;
445 struct coda_inode_info *cii;
446 struct file *host_file;
447 struct dentry *de;
448 struct venus_dirent *vdir;
449 unsigned long vdir_size = offsetof(struct venus_dirent, d_name);
450 unsigned int type;
451 struct qstr name;
452 ino_t ino;
453 int ret;
454
455 cfi = CODA_FTOC(coda_file);
456 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
457 host_file = cfi->cfi_container;
458
459 de = coda_file->f_path.dentry;
460 cii = ITOC(de->d_inode);
461
462 vdir = kmalloc(sizeof(*vdir), GFP_KERNEL);
463 if (!vdir) return -ENOMEM;
464
465 if (coda_file->f_pos == 0) {
466 ret = filldir(buf, ".", 1, 0, de->d_inode->i_ino, DT_DIR);
467 if (ret < 0)
468 goto out;
469 result++;
470 coda_file->f_pos++;
471 }
472 if (coda_file->f_pos == 1) {
473 ret = filldir(buf, "..", 2, 1, parent_ino(de), DT_DIR);
474 if (ret < 0)
475 goto out;
476 result++;
477 coda_file->f_pos++;
478 }
479 while (1) {
480 /* read entries from the directory file */
481 ret = kernel_read(host_file, coda_file->f_pos - 2, (char *)vdir,
482 sizeof(*vdir));
483 if (ret < 0) {
484 printk(KERN_ERR "coda readdir: read dir %s failed %d\n",
485 coda_f2s(&cii->c_fid), ret);
486 break;
487 }
488 if (ret == 0) break; /* end of directory file reached */
489
490 /* catch truncated reads */
491 if (ret < vdir_size || ret < vdir_size + vdir->d_namlen) {
492 printk(KERN_ERR "coda readdir: short read on %s\n",
493 coda_f2s(&cii->c_fid));
494 ret = -EBADF;
495 break;
496 }
497 /* validate whether the directory file actually makes sense */
498 if (vdir->d_reclen < vdir_size + vdir->d_namlen) {
499 printk(KERN_ERR "coda readdir: invalid dir %s\n",
500 coda_f2s(&cii->c_fid));
501 ret = -EBADF;
502 break;
503 }
504
505 name.len = vdir->d_namlen;
506 name.name = vdir->d_name;
507
508 /* Make sure we skip '.' and '..', we already got those */
509 if (name.name[0] == '.' && (name.len == 1 ||
510 (vdir->d_name[1] == '.' && name.len == 2)))
511 vdir->d_fileno = name.len = 0;
512
513 /* skip null entries */
514 if (vdir->d_fileno && name.len) {
515 /* try to look up this entry in the dcache, that way
516 * userspace doesn't have to worry about breaking
517 * getcwd by having mismatched inode numbers for
518 * internal volume mountpoints. */
519 ino = find_inode_number(de, &name);
520 if (!ino) ino = vdir->d_fileno;
521
522 type = CDT2DT(vdir->d_type);
523 ret = filldir(buf, name.name, name.len,
524 coda_file->f_pos, ino, type);
525 /* failure means no space for filling in this round */
526 if (ret < 0) break;
527 result++;
528 }
529 /* we'll always have progress because d_reclen is unsigned and
530 * we've already established it is non-zero. */
531 coda_file->f_pos += vdir->d_reclen;
532 }
533 out:
534 kfree(vdir);
535 return result ? result : ret;
536 }
537
538 /* called when a cache lookup succeeds */
539 static int coda_dentry_revalidate(struct dentry *de, unsigned int flags)
540 {
541 struct inode *inode;
542 struct coda_inode_info *cii;
543
544 if (flags & LOOKUP_RCU)
545 return -ECHILD;
546
547 inode = de->d_inode;
548 if (!inode || coda_isroot(inode))
549 goto out;
550 if (is_bad_inode(inode))
551 goto bad;
552
553 cii = ITOC(de->d_inode);
554 if (!(cii->c_flags & (C_PURGE | C_FLUSH)))
555 goto out;
556
557 shrink_dcache_parent(de);
558
559 /* propagate for a flush */
560 if (cii->c_flags & C_FLUSH)
561 coda_flag_inode_children(inode, C_FLUSH);
562
563 if (de->d_count > 1)
564 /* pretend it's valid, but don't change the flags */
565 goto out;
566
567 /* clear the flags. */
568 spin_lock(&cii->c_lock);
569 cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);
570 spin_unlock(&cii->c_lock);
571 bad:
572 return 0;
573 out:
574 return 1;
575 }
576
577 /*
578 * This is the callback from dput() when d_count is going to 0.
579 * We use this to unhash dentries with bad inodes.
580 */
581 static int coda_dentry_delete(const struct dentry * dentry)
582 {
583 int flags;
584
585 if (!dentry->d_inode)
586 return 0;
587
588 flags = (ITOC(dentry->d_inode)->c_flags) & C_PURGE;
589 if (is_bad_inode(dentry->d_inode) || flags) {
590 return 1;
591 }
592 return 0;
593 }
594
595
596
597 /*
598 * This is called when we want to check if the inode has
599 * changed on the server. Coda makes this easy since the
600 * cache manager Venus issues a downcall to the kernel when this
601 * happens
602 */
603 int coda_revalidate_inode(struct dentry *dentry)
604 {
605 struct coda_vattr attr;
606 int error;
607 int old_mode;
608 ino_t old_ino;
609 struct inode *inode = dentry->d_inode;
610 struct coda_inode_info *cii = ITOC(inode);
611
612 if (!cii->c_flags)
613 return 0;
614
615 if (cii->c_flags & (C_VATTR | C_PURGE | C_FLUSH)) {
616 error = venus_getattr(inode->i_sb, &(cii->c_fid), &attr);
617 if (error)
618 return -EIO;
619
620 /* this inode may be lost if:
621 - it's ino changed
622 - type changes must be permitted for repair and
623 missing mount points.
624 */
625 old_mode = inode->i_mode;
626 old_ino = inode->i_ino;
627 coda_vattr_to_iattr(inode, &attr);
628
629 if ((old_mode & S_IFMT) != (inode->i_mode & S_IFMT)) {
630 printk("Coda: inode %ld, fid %s changed type!\n",
631 inode->i_ino, coda_f2s(&(cii->c_fid)));
632 }
633
634 /* the following can happen when a local fid is replaced
635 with a global one, here we lose and declare the inode bad */
636 if (inode->i_ino != old_ino)
637 return -EIO;
638
639 coda_flag_inode_children(inode, C_FLUSH);
640
641 spin_lock(&cii->c_lock);
642 cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);
643 spin_unlock(&cii->c_lock);
644 }
645 return 0;
646 }
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