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switch coda
[linux-2.6/cjktty.git] / fs / coda / dir.c
blob9df71f0eb218b6c72fd65f846e63088a135cc193
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_linux.h>
27 #include <linux/coda_psdev.h>
28 #include <linux/coda_fs_i.h>
29 #include <linux/coda_cache.h>
30
31 #include "coda_int.h"
32
33 /* dir inode-ops */
34 static int coda_create(struct inode *dir, struct dentry *new, int mode, struct nameidata *nd);
35 static struct dentry *coda_lookup(struct inode *dir, struct dentry *target, struct nameidata *nd);
36 static int coda_link(struct dentry *old_dentry, struct inode *dir_inode,
37 struct dentry *entry);
38 static int coda_unlink(struct inode *dir_inode, struct dentry *entry);
39 static int coda_symlink(struct inode *dir_inode, struct dentry *entry,
40 const char *symname);
41 static int coda_mkdir(struct inode *dir_inode, struct dentry *entry, int mode);
42 static int coda_rmdir(struct inode *dir_inode, struct dentry *entry);
43 static int coda_rename(struct inode *old_inode, struct dentry *old_dentry,
44 struct inode *new_inode, struct dentry *new_dentry);
45
46 /* dir file-ops */
47 static int coda_readdir(struct file *file, void *buf, filldir_t filldir);
48
49 /* dentry ops */
50 static int coda_dentry_revalidate(struct dentry *de, struct nameidata *nd);
51 static int coda_dentry_delete(const struct dentry *);
52
53 /* support routines */
54 static int coda_venus_readdir(struct file *coda_file, void *buf,
55 filldir_t filldir);
56
57 /* same as fs/bad_inode.c */
58 static int coda_return_EIO(void)
59 {
60 return -EIO;
61 }
62 #define CODA_EIO_ERROR ((void *) (coda_return_EIO))
63
64 const struct dentry_operations coda_dentry_operations =
65 {
66 .d_revalidate = coda_dentry_revalidate,
67 .d_delete = coda_dentry_delete,
68 };
69
70 const struct inode_operations coda_dir_inode_operations =
71 {
72 .create = coda_create,
73 .lookup = coda_lookup,
74 .link = coda_link,
75 .unlink = coda_unlink,
76 .symlink = coda_symlink,
77 .mkdir = coda_mkdir,
78 .rmdir = coda_rmdir,
79 .mknod = CODA_EIO_ERROR,
80 .rename = coda_rename,
81 .permission = coda_permission,
82 .getattr = coda_getattr,
83 .setattr = coda_setattr,
84 };
85
86 const struct file_operations coda_dir_operations = {
87 .llseek = generic_file_llseek,
88 .read = generic_read_dir,
89 .readdir = coda_readdir,
90 .open = coda_open,
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 *inode = NULL;
101 struct CodaFid resfid = { { 0, } };
102 int type = 0;
103 int error = 0;
104 const char *name = entry->d_name.name;
105 size_t length = entry->d_name.len;
106
107 if (length > CODA_MAXNAMLEN) {
108 printk(KERN_ERR "name too long: lookup, %s (%*s)\n",
109 coda_i2s(dir), (int)length, name);
110 return ERR_PTR(-ENAMETOOLONG);
111 }
112
113 /* control object, create inode on the fly */
114 if (coda_isroot(dir) && coda_iscontrol(name, length)) {
115 error = coda_cnode_makectl(&inode, dir->i_sb);
116 type = CODA_NOCACHE;
117 goto exit;
118 }
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 if (error && error != -ENOENT)
126 return ERR_PTR(error);
127
128 exit:
129 if (inode && (type & CODA_NOCACHE))
130 coda_flag_inode(inode, C_VATTR | C_PURGE);
131
132 return d_splice_alias(inode, entry);
133 }
134
135
136 int coda_permission(struct inode *inode, int mask, unsigned int flags)
137 {
138 int error;
139
140 if (flags & IPERM_FLAG_RCU)
141 return -ECHILD;
142
143 mask &= MAY_READ | MAY_WRITE | MAY_EXEC;
144
145 if (!mask)
146 return 0;
147
148 if ((mask & MAY_EXEC) && !execute_ok(inode))
149 return -EACCES;
150
151 if (coda_cache_check(inode, mask))
152 return 0;
153
154 error = venus_access(inode->i_sb, coda_i2f(inode), mask);
155
156 if (!error)
157 coda_cache_enter(inode, mask);
158
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;
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 if (coda_isroot(dir) && coda_iscontrol(name, length))
205 return -EPERM;
206
207 error = venus_create(dir->i_sb, coda_i2f(dir), name, length,
208 0, mode, &newfid, &attrs);
209 if (error)
210 goto err_out;
211
212 inode = coda_iget(dir->i_sb, &newfid, &attrs);
213 if (IS_ERR(inode)) {
214 error = PTR_ERR(inode);
215 goto err_out;
216 }
217
218 /* invalidate the directory cnode's attributes */
219 coda_dir_update_mtime(dir);
220 d_instantiate(de, inode);
221 return 0;
222 err_out:
223 d_drop(de);
224 return error;
225 }
226
227 static int coda_mkdir(struct inode *dir, struct dentry *de, int mode)
228 {
229 struct inode *inode;
230 struct coda_vattr attrs;
231 const char *name = de->d_name.name;
232 int len = de->d_name.len;
233 int error;
234 struct CodaFid newfid;
235
236 if (coda_isroot(dir) && coda_iscontrol(name, len))
237 return -EPERM;
238
239 attrs.va_mode = mode;
240 error = venus_mkdir(dir->i_sb, coda_i2f(dir),
241 name, len, &newfid, &attrs);
242 if (error)
243 goto err_out;
244
245 inode = coda_iget(dir->i_sb, &newfid, &attrs);
246 if (IS_ERR(inode)) {
247 error = PTR_ERR(inode);
248 goto err_out;
249 }
250
251 /* invalidate the directory cnode's attributes */
252 coda_dir_inc_nlink(dir);
253 coda_dir_update_mtime(dir);
254 d_instantiate(de, inode);
255 return 0;
256 err_out:
257 d_drop(de);
258 return error;
259 }
260
261 /* try to make de an entry in dir_inodde linked to source_de */
262 static int coda_link(struct dentry *source_de, struct inode *dir_inode,
263 struct dentry *de)
264 {
265 struct inode *inode = source_de->d_inode;
266 const char * name = de->d_name.name;
267 int len = de->d_name.len;
268 int error;
269
270 if (coda_isroot(dir_inode) && coda_iscontrol(name, len))
271 return -EPERM;
272
273 error = venus_link(dir_inode->i_sb, coda_i2f(inode),
274 coda_i2f(dir_inode), (const char *)name, len);
275 if (error) {
276 d_drop(de);
277 return error;
278 }
279
280 coda_dir_update_mtime(dir_inode);
281 ihold(inode);
282 d_instantiate(de, inode);
283 inc_nlink(inode);
284 return 0;
285 }
286
287
288 static int coda_symlink(struct inode *dir_inode, struct dentry *de,
289 const char *symname)
290 {
291 const char *name = de->d_name.name;
292 int len = de->d_name.len;
293 int symlen;
294 int error;
295
296 if (coda_isroot(dir_inode) && coda_iscontrol(name, len))
297 return -EPERM;
298
299 symlen = strlen(symname);
300 if (symlen > CODA_MAXPATHLEN)
301 return -ENAMETOOLONG;
302
303 /*
304 * This entry is now negative. Since we do not create
305 * an inode for the entry we have to drop it.
306 */
307 d_drop(de);
308 error = venus_symlink(dir_inode->i_sb, coda_i2f(dir_inode), name, len,
309 symname, symlen);
310
311 /* mtime is no good anymore */
312 if (!error)
313 coda_dir_update_mtime(dir_inode);
314
315 return error;
316 }
317
318 /* destruction routines: unlink, rmdir */
319 static int coda_unlink(struct inode *dir, struct dentry *de)
320 {
321 int error;
322 const char *name = de->d_name.name;
323 int len = de->d_name.len;
324
325 error = venus_remove(dir->i_sb, coda_i2f(dir), name, len);
326 if (error)
327 return error;
328
329 coda_dir_update_mtime(dir);
330 drop_nlink(de->d_inode);
331 return 0;
332 }
333
334 static int coda_rmdir(struct inode *dir, struct dentry *de)
335 {
336 const char *name = de->d_name.name;
337 int len = de->d_name.len;
338 int error;
339
340 error = venus_rmdir(dir->i_sb, coda_i2f(dir), name, len);
341 if (!error) {
342 /* VFS may delete the child */
343 if (de->d_inode)
344 de->d_inode->i_nlink = 0;
345
346 /* fix the link count of the parent */
347 coda_dir_drop_nlink(dir);
348 coda_dir_update_mtime(dir);
349 }
350 return error;
351 }
352
353 /* rename */
354 static int coda_rename(struct inode *old_dir, struct dentry *old_dentry,
355 struct inode *new_dir, struct dentry *new_dentry)
356 {
357 const char *old_name = old_dentry->d_name.name;
358 const char *new_name = new_dentry->d_name.name;
359 int old_length = old_dentry->d_name.len;
360 int new_length = new_dentry->d_name.len;
361 int error;
362
363 error = venus_rename(old_dir->i_sb, coda_i2f(old_dir),
364 coda_i2f(new_dir), old_length, new_length,
365 (const char *) old_name, (const char *)new_name);
366 if (!error) {
367 if (new_dentry->d_inode) {
368 if (S_ISDIR(new_dentry->d_inode->i_mode)) {
369 coda_dir_drop_nlink(old_dir);
370 coda_dir_inc_nlink(new_dir);
371 }
372 coda_dir_update_mtime(old_dir);
373 coda_dir_update_mtime(new_dir);
374 coda_flag_inode(new_dentry->d_inode, C_VATTR);
375 } else {
376 coda_flag_inode(old_dir, C_VATTR);
377 coda_flag_inode(new_dir, C_VATTR);
378 }
379 }
380 return error;
381 }
382
383
384 /* file operations for directories */
385 static int coda_readdir(struct file *coda_file, void *buf, filldir_t filldir)
386 {
387 struct coda_file_info *cfi;
388 struct file *host_file;
389 int ret;
390
391 cfi = CODA_FTOC(coda_file);
392 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
393 host_file = cfi->cfi_container;
394
395 if (!host_file->f_op)
396 return -ENOTDIR;
397
398 if (host_file->f_op->readdir)
399 {
400 /* potemkin case: we were handed a directory inode.
401 * We can't use vfs_readdir because we have to keep the file
402 * position in sync between the coda_file and the host_file.
403 * and as such we need grab the inode mutex. */
404 struct inode *host_inode = host_file->f_path.dentry->d_inode;
405
406 mutex_lock(&host_inode->i_mutex);
407 host_file->f_pos = coda_file->f_pos;
408
409 ret = -ENOENT;
410 if (!IS_DEADDIR(host_inode)) {
411 ret = host_file->f_op->readdir(host_file, buf, filldir);
412 file_accessed(host_file);
413 }
414
415 coda_file->f_pos = host_file->f_pos;
416 mutex_unlock(&host_inode->i_mutex);
417 }
418 else /* Venus: we must read Venus dirents from a file */
419 ret = coda_venus_readdir(coda_file, buf, filldir);
420
421 return ret;
422 }
423
424 static inline unsigned int CDT2DT(unsigned char cdt)
425 {
426 unsigned int dt;
427
428 switch(cdt) {
429 case CDT_UNKNOWN: dt = DT_UNKNOWN; break;
430 case CDT_FIFO: dt = DT_FIFO; break;
431 case CDT_CHR: dt = DT_CHR; break;
432 case CDT_DIR: dt = DT_DIR; break;
433 case CDT_BLK: dt = DT_BLK; break;
434 case CDT_REG: dt = DT_REG; break;
435 case CDT_LNK: dt = DT_LNK; break;
436 case CDT_SOCK: dt = DT_SOCK; break;
437 case CDT_WHT: dt = DT_WHT; break;
438 default: dt = DT_UNKNOWN; break;
439 }
440 return dt;
441 }
442
443 /* support routines */
444 static int coda_venus_readdir(struct file *coda_file, void *buf,
445 filldir_t filldir)
446 {
447 int result = 0; /* # of entries returned */
448 struct coda_file_info *cfi;
449 struct coda_inode_info *cii;
450 struct file *host_file;
451 struct dentry *de;
452 struct venus_dirent *vdir;
453 unsigned long vdir_size =
454 (unsigned long)(&((struct venus_dirent *)0)->d_name);
455 unsigned int type;
456 struct qstr name;
457 ino_t ino;
458 int ret;
459
460 cfi = CODA_FTOC(coda_file);
461 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
462 host_file = cfi->cfi_container;
463
464 de = coda_file->f_path.dentry;
465 cii = ITOC(de->d_inode);
466
467 vdir = kmalloc(sizeof(*vdir), GFP_KERNEL);
468 if (!vdir) return -ENOMEM;
469
470 if (coda_file->f_pos == 0) {
471 ret = filldir(buf, ".", 1, 0, de->d_inode->i_ino, DT_DIR);
472 if (ret < 0)
473 goto out;
474 result++;
475 coda_file->f_pos++;
476 }
477 if (coda_file->f_pos == 1) {
478 ret = filldir(buf, "..", 2, 1, de->d_parent->d_inode->i_ino, DT_DIR);
479 if (ret < 0)
480 goto out;
481 result++;
482 coda_file->f_pos++;
483 }
484 while (1) {
485 /* read entries from the directory file */
486 ret = kernel_read(host_file, coda_file->f_pos - 2, (char *)vdir,
487 sizeof(*vdir));
488 if (ret < 0) {
489 printk(KERN_ERR "coda readdir: read dir %s failed %d\n",
490 coda_f2s(&cii->c_fid), ret);
491 break;
492 }
493 if (ret == 0) break; /* end of directory file reached */
494
495 /* catch truncated reads */
496 if (ret < vdir_size || ret < vdir_size + vdir->d_namlen) {
497 printk(KERN_ERR "coda readdir: short read on %s\n",
498 coda_f2s(&cii->c_fid));
499 ret = -EBADF;
500 break;
501 }
502 /* validate whether the directory file actually makes sense */
503 if (vdir->d_reclen < vdir_size + vdir->d_namlen) {
504 printk(KERN_ERR "coda readdir: invalid dir %s\n",
505 coda_f2s(&cii->c_fid));
506 ret = -EBADF;
507 break;
508 }
509
510 name.len = vdir->d_namlen;
511 name.name = vdir->d_name;
512
513 /* Make sure we skip '.' and '..', we already got those */
514 if (name.name[0] == '.' && (name.len == 1 ||
515 (vdir->d_name[1] == '.' && name.len == 2)))
516 vdir->d_fileno = name.len = 0;
517
518 /* skip null entries */
519 if (vdir->d_fileno && name.len) {
520 /* try to look up this entry in the dcache, that way
521 * userspace doesn't have to worry about breaking
522 * getcwd by having mismatched inode numbers for
523 * internal volume mountpoints. */
524 ino = find_inode_number(de, &name);
525 if (!ino) ino = vdir->d_fileno;
526
527 type = CDT2DT(vdir->d_type);
528 ret = filldir(buf, name.name, name.len,
529 coda_file->f_pos, ino, type);
530 /* failure means no space for filling in this round */
531 if (ret < 0) break;
532 result++;
533 }
534 /* we'll always have progress because d_reclen is unsigned and
535 * we've already established it is non-zero. */
536 coda_file->f_pos += vdir->d_reclen;
537 }
538 out:
539 kfree(vdir);
540 return result ? result : ret;
541 }
542
543 /* called when a cache lookup succeeds */
544 static int coda_dentry_revalidate(struct dentry *de, struct nameidata *nd)
545 {
546 struct inode *inode;
547 struct coda_inode_info *cii;
548
549 if (nd->flags & LOOKUP_RCU)
550 return -ECHILD;
551
552 inode = de->d_inode;
553 if (!inode || coda_isroot(inode))
554 goto out;
555 if (is_bad_inode(inode))
556 goto bad;
557
558 cii = ITOC(de->d_inode);
559 if (!(cii->c_flags & (C_PURGE | C_FLUSH)))
560 goto out;
561
562 shrink_dcache_parent(de);
563
564 /* propagate for a flush */
565 if (cii->c_flags & C_FLUSH)
566 coda_flag_inode_children(inode, C_FLUSH);
567
568 if (de->d_count > 1)
569 /* pretend it's valid, but don't change the flags */
570 goto out;
571
572 /* clear the flags. */
573 spin_lock(&cii->c_lock);
574 cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);
575 spin_unlock(&cii->c_lock);
576 bad:
577 return 0;
578 out:
579 return 1;
580 }
581
582 /*
583 * This is the callback from dput() when d_count is going to 0.
584 * We use this to unhash dentries with bad inodes.
585 */
586 static int coda_dentry_delete(const struct dentry * dentry)
587 {
588 int flags;
589
590 if (!dentry->d_inode)
591 return 0;
592
593 flags = (ITOC(dentry->d_inode)->c_flags) & C_PURGE;
594 if (is_bad_inode(dentry->d_inode) || flags) {
595 return 1;
596 }
597 return 0;
598 }
599
600
601
602 /*
603 * This is called when we want to check if the inode has
604 * changed on the server. Coda makes this easy since the
605 * cache manager Venus issues a downcall to the kernel when this
606 * happens
607 */
608 int coda_revalidate_inode(struct dentry *dentry)
609 {
610 struct coda_vattr attr;
611 int error;
612 int old_mode;
613 ino_t old_ino;
614 struct inode *inode = dentry->d_inode;
615 struct coda_inode_info *cii = ITOC(inode);
616
617 if (!cii->c_flags)
618 return 0;
619
620 if (cii->c_flags & (C_VATTR | C_PURGE | C_FLUSH)) {
621 error = venus_getattr(inode->i_sb, &(cii->c_fid), &attr);
622 if (error)
623 return -EIO;
624
625 /* this inode may be lost if:
626 - it's ino changed
627 - type changes must be permitted for repair and
628 missing mount points.
629 */
630 old_mode = inode->i_mode;
631 old_ino = inode->i_ino;
632 coda_vattr_to_iattr(inode, &attr);
633
634 if ((old_mode & S_IFMT) != (inode->i_mode & S_IFMT)) {
635 printk("Coda: inode %ld, fid %s changed type!\n",
636 inode->i_ino, coda_f2s(&(cii->c_fid)));
637 }
638
639 /* the following can happen when a local fid is replaced
640 with a global one, here we lose and declare the inode bad */
641 if (inode->i_ino != old_ino)
642 return -EIO;
643
644 coda_flag_inode_children(inode, C_FLUSH);
645
646 spin_lock(&cii->c_lock);
647 cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);
648 spin_unlock(&cii->c_lock);
649 }
650 return 0;
651 }
CJK support for tty framebuffer vt