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[media] media: davinci: vpif: Switch to pad-level DV operations
[linux-2.6/btrfs-unstable.git] / fs / coda / dir.c
blob5efbb5ee0adc627e53e425968287ab68334a195c
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, struct dir_context *ctx);
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 *, struct dir_context *);
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 const 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 .iterate = 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, unsigned int flags)
97 {
98 struct super_block *sb = dir->i_sb;
99 const char *name = entry->d_name.name;
100 size_t length = entry->d_name.len;
101 struct inode *inode;
102 int type = 0;
103
104 if (length > CODA_MAXNAMLEN) {
105 printk(KERN_ERR "name too long: lookup, %s (%*s)\n",
106 coda_i2s(dir), (int)length, name);
107 return ERR_PTR(-ENAMETOOLONG);
108 }
109
110 /* control object, create inode on the fly */
111 if (coda_isroot(dir) && coda_iscontrol(name, length)) {
112 inode = coda_cnode_makectl(sb);
113 type = CODA_NOCACHE;
114 } else {
115 struct CodaFid fid = { { 0, } };
116 int error = venus_lookup(sb, coda_i2f(dir), name, length,
117 &type, &fid);
118 inode = !error ? coda_cnode_make(&fid, sb) : ERR_PTR(error);
119 }
120
121 if (!IS_ERR(inode) && (type & CODA_NOCACHE))
122 coda_flag_inode(inode, C_VATTR | C_PURGE);
123
124 if (inode == ERR_PTR(-ENOENT))
125 inode = NULL;
126
127 return d_splice_alias(inode, entry);
128 }
129
130
131 int coda_permission(struct inode *inode, int mask)
132 {
133 int error;
134
135 if (mask & MAY_NOT_BLOCK)
136 return -ECHILD;
137
138 mask &= MAY_READ | MAY_WRITE | MAY_EXEC;
139
140 if (!mask)
141 return 0;
142
143 if ((mask & MAY_EXEC) && !execute_ok(inode))
144 return -EACCES;
145
146 if (coda_cache_check(inode, mask))
147 return 0;
148
149 error = venus_access(inode->i_sb, coda_i2f(inode), mask);
150
151 if (!error)
152 coda_cache_enter(inode, mask);
153
154 return error;
155 }
156
157
158 static inline void coda_dir_update_mtime(struct inode *dir)
159 {
160 #ifdef REQUERY_VENUS_FOR_MTIME
161 /* invalidate the directory cnode's attributes so we refetch the
162 * attributes from venus next time the inode is referenced */
163 coda_flag_inode(dir, C_VATTR);
164 #else
165 /* optimistically we can also act as if our nose bleeds. The
166 * granularity of the mtime is coarse anyways so we might actually be
167 * right most of the time. Note: we only do this for directories. */
168 dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
169 #endif
170 }
171
172 /* we have to wrap inc_nlink/drop_nlink because sometimes userspace uses a
173 * trick to fool GNU find's optimizations. If we can't be sure of the link
174 * (because of volume mount points) we set i_nlink to 1 which forces find
175 * to consider every child as a possible directory. We should also never
176 * see an increment or decrement for deleted directories where i_nlink == 0 */
177 static inline void coda_dir_inc_nlink(struct inode *dir)
178 {
179 if (dir->i_nlink >= 2)
180 inc_nlink(dir);
181 }
182
183 static inline void coda_dir_drop_nlink(struct inode *dir)
184 {
185 if (dir->i_nlink > 2)
186 drop_nlink(dir);
187 }
188
189 /* creation routines: create, mknod, mkdir, link, symlink */
190 static int coda_create(struct inode *dir, struct dentry *de, umode_t mode, bool excl)
191 {
192 int error;
193 const char *name=de->d_name.name;
194 int length=de->d_name.len;
195 struct inode *inode;
196 struct CodaFid newfid;
197 struct coda_vattr attrs;
198
199 if (coda_isroot(dir) && coda_iscontrol(name, length))
200 return -EPERM;
201
202 error = venus_create(dir->i_sb, coda_i2f(dir), name, length,
203 0, mode, &newfid, &attrs);
204 if (error)
205 goto err_out;
206
207 inode = coda_iget(dir->i_sb, &newfid, &attrs);
208 if (IS_ERR(inode)) {
209 error = PTR_ERR(inode);
210 goto err_out;
211 }
212
213 /* invalidate the directory cnode's attributes */
214 coda_dir_update_mtime(dir);
215 d_instantiate(de, inode);
216 return 0;
217 err_out:
218 d_drop(de);
219 return error;
220 }
221
222 static int coda_mkdir(struct inode *dir, struct dentry *de, umode_t mode)
223 {
224 struct inode *inode;
225 struct coda_vattr attrs;
226 const char *name = de->d_name.name;
227 int len = de->d_name.len;
228 int error;
229 struct CodaFid newfid;
230
231 if (coda_isroot(dir) && coda_iscontrol(name, len))
232 return -EPERM;
233
234 attrs.va_mode = mode;
235 error = venus_mkdir(dir->i_sb, coda_i2f(dir),
236 name, len, &newfid, &attrs);
237 if (error)
238 goto err_out;
239
240 inode = coda_iget(dir->i_sb, &newfid, &attrs);
241 if (IS_ERR(inode)) {
242 error = PTR_ERR(inode);
243 goto err_out;
244 }
245
246 /* invalidate the directory cnode's attributes */
247 coda_dir_inc_nlink(dir);
248 coda_dir_update_mtime(dir);
249 d_instantiate(de, inode);
250 return 0;
251 err_out:
252 d_drop(de);
253 return error;
254 }
255
256 /* try to make de an entry in dir_inodde linked to source_de */
257 static int coda_link(struct dentry *source_de, struct inode *dir_inode,
258 struct dentry *de)
259 {
260 struct inode *inode = source_de->d_inode;
261 const char * name = de->d_name.name;
262 int len = de->d_name.len;
263 int error;
264
265 if (coda_isroot(dir_inode) && coda_iscontrol(name, len))
266 return -EPERM;
267
268 error = venus_link(dir_inode->i_sb, coda_i2f(inode),
269 coda_i2f(dir_inode), (const char *)name, len);
270 if (error) {
271 d_drop(de);
272 return error;
273 }
274
275 coda_dir_update_mtime(dir_inode);
276 ihold(inode);
277 d_instantiate(de, inode);
278 inc_nlink(inode);
279 return 0;
280 }
281
282
283 static int coda_symlink(struct inode *dir_inode, struct dentry *de,
284 const char *symname)
285 {
286 const char *name = de->d_name.name;
287 int len = de->d_name.len;
288 int symlen;
289 int error;
290
291 if (coda_isroot(dir_inode) && coda_iscontrol(name, len))
292 return -EPERM;
293
294 symlen = strlen(symname);
295 if (symlen > CODA_MAXPATHLEN)
296 return -ENAMETOOLONG;
297
298 /*
299 * This entry is now negative. Since we do not create
300 * an inode for the entry we have to drop it.
301 */
302 d_drop(de);
303 error = venus_symlink(dir_inode->i_sb, coda_i2f(dir_inode), name, len,
304 symname, symlen);
305
306 /* mtime is no good anymore */
307 if (!error)
308 coda_dir_update_mtime(dir_inode);
309
310 return error;
311 }
312
313 /* destruction routines: unlink, rmdir */
314 static int coda_unlink(struct inode *dir, struct dentry *de)
315 {
316 int error;
317 const char *name = de->d_name.name;
318 int len = de->d_name.len;
319
320 error = venus_remove(dir->i_sb, coda_i2f(dir), name, len);
321 if (error)
322 return error;
323
324 coda_dir_update_mtime(dir);
325 drop_nlink(de->d_inode);
326 return 0;
327 }
328
329 static int coda_rmdir(struct inode *dir, struct dentry *de)
330 {
331 const char *name = de->d_name.name;
332 int len = de->d_name.len;
333 int error;
334
335 error = venus_rmdir(dir->i_sb, coda_i2f(dir), name, len);
336 if (!error) {
337 /* VFS may delete the child */
338 if (de->d_inode)
339 clear_nlink(de->d_inode);
340
341 /* fix the link count of the parent */
342 coda_dir_drop_nlink(dir);
343 coda_dir_update_mtime(dir);
344 }
345 return error;
346 }
347
348 /* rename */
349 static int coda_rename(struct inode *old_dir, struct dentry *old_dentry,
350 struct inode *new_dir, struct dentry *new_dentry)
351 {
352 const char *old_name = old_dentry->d_name.name;
353 const char *new_name = new_dentry->d_name.name;
354 int old_length = old_dentry->d_name.len;
355 int new_length = new_dentry->d_name.len;
356 int error;
357
358 error = venus_rename(old_dir->i_sb, coda_i2f(old_dir),
359 coda_i2f(new_dir), old_length, new_length,
360 (const char *) old_name, (const char *)new_name);
361 if (!error) {
362 if (new_dentry->d_inode) {
363 if (S_ISDIR(new_dentry->d_inode->i_mode)) {
364 coda_dir_drop_nlink(old_dir);
365 coda_dir_inc_nlink(new_dir);
366 }
367 coda_dir_update_mtime(old_dir);
368 coda_dir_update_mtime(new_dir);
369 coda_flag_inode(new_dentry->d_inode, C_VATTR);
370 } else {
371 coda_flag_inode(old_dir, C_VATTR);
372 coda_flag_inode(new_dir, C_VATTR);
373 }
374 }
375 return error;
376 }
377
378
379 /* file operations for directories */
380 static int coda_readdir(struct file *coda_file, struct dir_context *ctx)
381 {
382 struct coda_file_info *cfi;
383 struct file *host_file;
384 int ret;
385
386 cfi = CODA_FTOC(coda_file);
387 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
388 host_file = cfi->cfi_container;
389
390 if (host_file->f_op->iterate) {
391 struct inode *host_inode = file_inode(host_file);
392 mutex_lock(&host_inode->i_mutex);
393 ret = -ENOENT;
394 if (!IS_DEADDIR(host_inode)) {
395 ret = host_file->f_op->iterate(host_file, ctx);
396 file_accessed(host_file);
397 }
398 mutex_unlock(&host_inode->i_mutex);
399 return ret;
400 }
401 /* Venus: we must read Venus dirents from a file */
402 return coda_venus_readdir(coda_file, ctx);
403 }
404
405 static inline unsigned int CDT2DT(unsigned char cdt)
406 {
407 unsigned int dt;
408
409 switch(cdt) {
410 case CDT_UNKNOWN: dt = DT_UNKNOWN; break;
411 case CDT_FIFO: dt = DT_FIFO; break;
412 case CDT_CHR: dt = DT_CHR; break;
413 case CDT_DIR: dt = DT_DIR; break;
414 case CDT_BLK: dt = DT_BLK; break;
415 case CDT_REG: dt = DT_REG; break;
416 case CDT_LNK: dt = DT_LNK; break;
417 case CDT_SOCK: dt = DT_SOCK; break;
418 case CDT_WHT: dt = DT_WHT; break;
419 default: dt = DT_UNKNOWN; break;
420 }
421 return dt;
422 }
423
424 /* support routines */
425 static int coda_venus_readdir(struct file *coda_file, struct dir_context *ctx)
426 {
427 struct coda_file_info *cfi;
428 struct coda_inode_info *cii;
429 struct file *host_file;
430 struct dentry *de;
431 struct venus_dirent *vdir;
432 unsigned long vdir_size = offsetof(struct venus_dirent, d_name);
433 unsigned int type;
434 struct qstr name;
435 ino_t ino;
436 int ret;
437
438 cfi = CODA_FTOC(coda_file);
439 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
440 host_file = cfi->cfi_container;
441
442 de = coda_file->f_path.dentry;
443 cii = ITOC(de->d_inode);
444
445 vdir = kmalloc(sizeof(*vdir), GFP_KERNEL);
446 if (!vdir) return -ENOMEM;
447
448 if (!dir_emit_dots(coda_file, ctx))
449 goto out;
450
451 while (1) {
452 /* read entries from the directory file */
453 ret = kernel_read(host_file, ctx->pos - 2, (char *)vdir,
454 sizeof(*vdir));
455 if (ret < 0) {
456 printk(KERN_ERR "coda readdir: read dir %s failed %d\n",
457 coda_f2s(&cii->c_fid), ret);
458 break;
459 }
460 if (ret == 0) break; /* end of directory file reached */
461
462 /* catch truncated reads */
463 if (ret < vdir_size || ret < vdir_size + vdir->d_namlen) {
464 printk(KERN_ERR "coda readdir: short read on %s\n",
465 coda_f2s(&cii->c_fid));
466 ret = -EBADF;
467 break;
468 }
469 /* validate whether the directory file actually makes sense */
470 if (vdir->d_reclen < vdir_size + vdir->d_namlen) {
471 printk(KERN_ERR "coda readdir: invalid dir %s\n",
472 coda_f2s(&cii->c_fid));
473 ret = -EBADF;
474 break;
475 }
476
477 name.len = vdir->d_namlen;
478 name.name = vdir->d_name;
479
480 /* Make sure we skip '.' and '..', we already got those */
481 if (name.name[0] == '.' && (name.len == 1 ||
482 (name.name[1] == '.' && name.len == 2)))
483 vdir->d_fileno = name.len = 0;
484
485 /* skip null entries */
486 if (vdir->d_fileno && name.len) {
487 ino = vdir->d_fileno;
488 type = CDT2DT(vdir->d_type);
489 if (!dir_emit(ctx, name.name, name.len, ino, type))
490 break;
491 }
492 /* we'll always have progress because d_reclen is unsigned and
493 * we've already established it is non-zero. */
494 ctx->pos += vdir->d_reclen;
495 }
496 out:
497 kfree(vdir);
498 return 0;
499 }
500
501 /* called when a cache lookup succeeds */
502 static int coda_dentry_revalidate(struct dentry *de, unsigned int flags)
503 {
504 struct inode *inode;
505 struct coda_inode_info *cii;
506
507 if (flags & LOOKUP_RCU)
508 return -ECHILD;
509
510 inode = de->d_inode;
511 if (!inode || coda_isroot(inode))
512 goto out;
513 if (is_bad_inode(inode))
514 goto bad;
515
516 cii = ITOC(de->d_inode);
517 if (!(cii->c_flags & (C_PURGE | C_FLUSH)))
518 goto out;
519
520 shrink_dcache_parent(de);
521
522 /* propagate for a flush */
523 if (cii->c_flags & C_FLUSH)
524 coda_flag_inode_children(inode, C_FLUSH);
525
526 if (d_count(de) > 1)
527 /* pretend it's valid, but don't change the flags */
528 goto out;
529
530 /* clear the flags. */
531 spin_lock(&cii->c_lock);
532 cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);
533 spin_unlock(&cii->c_lock);
534 bad:
535 return 0;
536 out:
537 return 1;
538 }
539
540 /*
541 * This is the callback from dput() when d_count is going to 0.
542 * We use this to unhash dentries with bad inodes.
543 */
544 static int coda_dentry_delete(const struct dentry * dentry)
545 {
546 int flags;
547
548 if (!dentry->d_inode)
549 return 0;
550
551 flags = (ITOC(dentry->d_inode)->c_flags) & C_PURGE;
552 if (is_bad_inode(dentry->d_inode) || flags) {
553 return 1;
554 }
555 return 0;
556 }
557
558
559
560 /*
561 * This is called when we want to check if the inode has
562 * changed on the server. Coda makes this easy since the
563 * cache manager Venus issues a downcall to the kernel when this
564 * happens
565 */
566 int coda_revalidate_inode(struct inode *inode)
567 {
568 struct coda_vattr attr;
569 int error;
570 int old_mode;
571 ino_t old_ino;
572 struct coda_inode_info *cii = ITOC(inode);
573
574 if (!cii->c_flags)
575 return 0;
576
577 if (cii->c_flags & (C_VATTR | C_PURGE | C_FLUSH)) {
578 error = venus_getattr(inode->i_sb, &(cii->c_fid), &attr);
579 if (error)
580 return -EIO;
581
582 /* this inode may be lost if:
583 - it's ino changed
584 - type changes must be permitted for repair and
585 missing mount points.
586 */
587 old_mode = inode->i_mode;
588 old_ino = inode->i_ino;
589 coda_vattr_to_iattr(inode, &attr);
590
591 if ((old_mode & S_IFMT) != (inode->i_mode & S_IFMT)) {
592 printk("Coda: inode %ld, fid %s changed type!\n",
593 inode->i_ino, coda_f2s(&(cii->c_fid)));
594 }
595
596 /* the following can happen when a local fid is replaced
597 with a global one, here we lose and declare the inode bad */
598 if (inode->i_ino != old_ino)
599 return -EIO;
600
601 coda_flag_inode_children(inode, C_FLUSH);
602
603 spin_lock(&cii->c_lock);
604 cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);
605 spin_unlock(&cii->c_lock);
606 }
607 return 0;
608 }
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