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Merge remote-tracking branch 'moduleh/module.h-split'
[linux-2.6/next.git] / fs / coda / dir.c
blob0239433f50cbe25749896439fc124131afcdf164
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, 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(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, 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 if (inode && (type & CODA_NOCACHE))
129 coda_flag_inode(inode, C_VATTR | C_PURGE);
130
131 return d_splice_alias(inode, entry);
132 }
133
134
135 int coda_permission(struct inode *inode, int mask)
136 {
137 int error;
138
139 if (mask & MAY_NOT_BLOCK)
140 return -ECHILD;
141
142 mask &= MAY_READ | MAY_WRITE | MAY_EXEC;
143
144 if (!mask)
145 return 0;
146
147 if ((mask & MAY_EXEC) && !execute_ok(inode))
148 return -EACCES;
149
150 if (coda_cache_check(inode, mask))
151 return 0;
152
153 error = venus_access(inode->i_sb, coda_i2f(inode), mask);
154
155 if (!error)
156 coda_cache_enter(inode, mask);
157
158 return error;
159 }
160
161
162 static inline void coda_dir_update_mtime(struct inode *dir)
163 {
164 #ifdef REQUERY_VENUS_FOR_MTIME
165 /* invalidate the directory cnode's attributes so we refetch the
166 * attributes from venus next time the inode is referenced */
167 coda_flag_inode(dir, C_VATTR);
168 #else
169 /* optimistically we can also act as if our nose bleeds. The
170 * granularity of the mtime is coarse anyways so we might actually be
171 * right most of the time. Note: we only do this for directories. */
172 dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
173 #endif
174 }
175
176 /* we have to wrap inc_nlink/drop_nlink because sometimes userspace uses a
177 * trick to fool GNU find's optimizations. If we can't be sure of the link
178 * (because of volume mount points) we set i_nlink to 1 which forces find
179 * to consider every child as a possible directory. We should also never
180 * see an increment or decrement for deleted directories where i_nlink == 0 */
181 static inline void coda_dir_inc_nlink(struct inode *dir)
182 {
183 if (dir->i_nlink >= 2)
184 inc_nlink(dir);
185 }
186
187 static inline void coda_dir_drop_nlink(struct inode *dir)
188 {
189 if (dir->i_nlink > 2)
190 drop_nlink(dir);
191 }
192
193 /* creation routines: create, mknod, mkdir, link, symlink */
194 static int coda_create(struct inode *dir, struct dentry *de, int mode, struct nameidata *nd)
195 {
196 int error;
197 const char *name=de->d_name.name;
198 int length=de->d_name.len;
199 struct inode *inode;
200 struct CodaFid newfid;
201 struct coda_vattr attrs;
202
203 if (coda_isroot(dir) && coda_iscontrol(name, length))
204 return -EPERM;
205
206 error = venus_create(dir->i_sb, coda_i2f(dir), name, length,
207 0, mode, &newfid, &attrs);
208 if (error)
209 goto err_out;
210
211 inode = coda_iget(dir->i_sb, &newfid, &attrs);
212 if (IS_ERR(inode)) {
213 error = PTR_ERR(inode);
214 goto err_out;
215 }
216
217 /* invalidate the directory cnode's attributes */
218 coda_dir_update_mtime(dir);
219 d_instantiate(de, inode);
220 return 0;
221 err_out:
222 d_drop(de);
223 return error;
224 }
225
226 static int coda_mkdir(struct inode *dir, struct dentry *de, int mode)
227 {
228 struct inode *inode;
229 struct coda_vattr attrs;
230 const char *name = de->d_name.name;
231 int len = de->d_name.len;
232 int error;
233 struct CodaFid newfid;
234
235 if (coda_isroot(dir) && coda_iscontrol(name, len))
236 return -EPERM;
237
238 attrs.va_mode = mode;
239 error = venus_mkdir(dir->i_sb, coda_i2f(dir),
240 name, len, &newfid, &attrs);
241 if (error)
242 goto err_out;
243
244 inode = coda_iget(dir->i_sb, &newfid, &attrs);
245 if (IS_ERR(inode)) {
246 error = PTR_ERR(inode);
247 goto err_out;
248 }
249
250 /* invalidate the directory cnode's attributes */
251 coda_dir_inc_nlink(dir);
252 coda_dir_update_mtime(dir);
253 d_instantiate(de, inode);
254 return 0;
255 err_out:
256 d_drop(de);
257 return error;
258 }
259
260 /* try to make de an entry in dir_inodde linked to source_de */
261 static int coda_link(struct dentry *source_de, struct inode *dir_inode,
262 struct dentry *de)
263 {
264 struct inode *inode = source_de->d_inode;
265 const char * name = de->d_name.name;
266 int len = de->d_name.len;
267 int error;
268
269 if (coda_isroot(dir_inode) && coda_iscontrol(name, len))
270 return -EPERM;
271
272 error = venus_link(dir_inode->i_sb, coda_i2f(inode),
273 coda_i2f(dir_inode), (const char *)name, len);
274 if (error) {
275 d_drop(de);
276 return error;
277 }
278
279 coda_dir_update_mtime(dir_inode);
280 ihold(inode);
281 d_instantiate(de, inode);
282 inc_nlink(inode);
283 return 0;
284 }
285
286
287 static int coda_symlink(struct inode *dir_inode, struct dentry *de,
288 const char *symname)
289 {
290 const char *name = de->d_name.name;
291 int len = de->d_name.len;
292 int symlen;
293 int error;
294
295 if (coda_isroot(dir_inode) && coda_iscontrol(name, len))
296 return -EPERM;
297
298 symlen = strlen(symname);
299 if (symlen > CODA_MAXPATHLEN)
300 return -ENAMETOOLONG;
301
302 /*
303 * This entry is now negative. Since we do not create
304 * an inode for the entry we have to drop it.
305 */
306 d_drop(de);
307 error = venus_symlink(dir_inode->i_sb, coda_i2f(dir_inode), name, len,
308 symname, symlen);
309
310 /* mtime is no good anymore */
311 if (!error)
312 coda_dir_update_mtime(dir_inode);
313
314 return error;
315 }
316
317 /* destruction routines: unlink, rmdir */
318 static int coda_unlink(struct inode *dir, struct dentry *de)
319 {
320 int error;
321 const char *name = de->d_name.name;
322 int len = de->d_name.len;
323
324 error = venus_remove(dir->i_sb, coda_i2f(dir), name, len);
325 if (error)
326 return error;
327
328 coda_dir_update_mtime(dir);
329 drop_nlink(de->d_inode);
330 return 0;
331 }
332
333 static int coda_rmdir(struct inode *dir, struct dentry *de)
334 {
335 const char *name = de->d_name.name;
336 int len = de->d_name.len;
337 int error;
338
339 error = venus_rmdir(dir->i_sb, coda_i2f(dir), name, len);
340 if (!error) {
341 /* VFS may delete the child */
342 if (de->d_inode)
343 de->d_inode->i_nlink = 0;
344
345 /* fix the link count of the parent */
346 coda_dir_drop_nlink(dir);
347 coda_dir_update_mtime(dir);
348 }
349 return error;
350 }
351
352 /* rename */
353 static int coda_rename(struct inode *old_dir, struct dentry *old_dentry,
354 struct inode *new_dir, struct dentry *new_dentry)
355 {
356 const char *old_name = old_dentry->d_name.name;
357 const char *new_name = new_dentry->d_name.name;
358 int old_length = old_dentry->d_name.len;
359 int new_length = new_dentry->d_name.len;
360 int error;
361
362 error = venus_rename(old_dir->i_sb, coda_i2f(old_dir),
363 coda_i2f(new_dir), old_length, new_length,
364 (const char *) old_name, (const char *)new_name);
365 if (!error) {
366 if (new_dentry->d_inode) {
367 if (S_ISDIR(new_dentry->d_inode->i_mode)) {
368 coda_dir_drop_nlink(old_dir);
369 coda_dir_inc_nlink(new_dir);
370 }
371 coda_dir_update_mtime(old_dir);
372 coda_dir_update_mtime(new_dir);
373 coda_flag_inode(new_dentry->d_inode, C_VATTR);
374 } else {
375 coda_flag_inode(old_dir, C_VATTR);
376 coda_flag_inode(new_dir, C_VATTR);
377 }
378 }
379 return error;
380 }
381
382
383 /* file operations for directories */
384 static int coda_readdir(struct file *coda_file, void *buf, filldir_t filldir)
385 {
386 struct coda_file_info *cfi;
387 struct file *host_file;
388 int ret;
389
390 cfi = CODA_FTOC(coda_file);
391 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
392 host_file = cfi->cfi_container;
393
394 if (!host_file->f_op)
395 return -ENOTDIR;
396
397 if (host_file->f_op->readdir)
398 {
399 /* potemkin case: we were handed a directory inode.
400 * We can't use vfs_readdir because we have to keep the file
401 * position in sync between the coda_file and the host_file.
402 * and as such we need grab the inode mutex. */
403 struct inode *host_inode = host_file->f_path.dentry->d_inode;
404
405 mutex_lock(&host_inode->i_mutex);
406 host_file->f_pos = coda_file->f_pos;
407
408 ret = -ENOENT;
409 if (!IS_DEADDIR(host_inode)) {
410 ret = host_file->f_op->readdir(host_file, buf, filldir);
411 file_accessed(host_file);
412 }
413
414 coda_file->f_pos = host_file->f_pos;
415 mutex_unlock(&host_inode->i_mutex);
416 }
417 else /* Venus: we must read Venus dirents from a file */
418 ret = coda_venus_readdir(coda_file, buf, filldir);
419
420 return ret;
421 }
422
423 static inline unsigned int CDT2DT(unsigned char cdt)
424 {
425 unsigned int dt;
426
427 switch(cdt) {
428 case CDT_UNKNOWN: dt = DT_UNKNOWN; break;
429 case CDT_FIFO: dt = DT_FIFO; break;
430 case CDT_CHR: dt = DT_CHR; break;
431 case CDT_DIR: dt = DT_DIR; break;
432 case CDT_BLK: dt = DT_BLK; break;
433 case CDT_REG: dt = DT_REG; break;
434 case CDT_LNK: dt = DT_LNK; break;
435 case CDT_SOCK: dt = DT_SOCK; break;
436 case CDT_WHT: dt = DT_WHT; break;
437 default: dt = DT_UNKNOWN; break;
438 }
439 return dt;
440 }
441
442 /* support routines */
443 static int coda_venus_readdir(struct file *coda_file, void *buf,
444 filldir_t filldir)
445 {
446 int result = 0; /* # of entries returned */
447 struct coda_file_info *cfi;
448 struct coda_inode_info *cii;
449 struct file *host_file;
450 struct dentry *de;
451 struct venus_dirent *vdir;
452 unsigned long vdir_size = offsetof(struct venus_dirent, 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, parent_ino(de), 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;
545 struct coda_inode_info *cii;
546
547 if (nd->flags & LOOKUP_RCU)
548 return -ECHILD;
549
550 inode = de->d_inode;
551 if (!inode || coda_isroot(inode))
552 goto out;
553 if (is_bad_inode(inode))
554 goto bad;
555
556 cii = ITOC(de->d_inode);
557 if (!(cii->c_flags & (C_PURGE | C_FLUSH)))
558 goto out;
559
560 shrink_dcache_parent(de);
561
562 /* propagate for a flush */
563 if (cii->c_flags & C_FLUSH)
564 coda_flag_inode_children(inode, C_FLUSH);
565
566 if (de->d_count > 1)
567 /* pretend it's valid, but don't change the flags */
568 goto out;
569
570 /* clear the flags. */
571 spin_lock(&cii->c_lock);
572 cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);
573 spin_unlock(&cii->c_lock);
574 bad:
575 return 0;
576 out:
577 return 1;
578 }
579
580 /*
581 * This is the callback from dput() when d_count is going to 0.
582 * We use this to unhash dentries with bad inodes.
583 */
584 static int coda_dentry_delete(const struct dentry * dentry)
585 {
586 int flags;
587
588 if (!dentry->d_inode)
589 return 0;
590
591 flags = (ITOC(dentry->d_inode)->c_flags) & C_PURGE;
592 if (is_bad_inode(dentry->d_inode) || flags) {
593 return 1;
594 }
595 return 0;
596 }
597
598
599
600 /*
601 * This is called when we want to check if the inode has
602 * changed on the server. Coda makes this easy since the
603 * cache manager Venus issues a downcall to the kernel when this
604 * happens
605 */
606 int coda_revalidate_inode(struct dentry *dentry)
607 {
608 struct coda_vattr attr;
609 int error;
610 int old_mode;
611 ino_t old_ino;
612 struct inode *inode = dentry->d_inode;
613 struct coda_inode_info *cii = ITOC(inode);
614
615 if (!cii->c_flags)
616 return 0;
617
618 if (cii->c_flags & (C_VATTR | C_PURGE | C_FLUSH)) {
619 error = venus_getattr(inode->i_sb, &(cii->c_fid), &attr);
620 if (error)
621 return -EIO;
622
623 /* this inode may be lost if:
624 - it's ino changed
625 - type changes must be permitted for repair and
626 missing mount points.
627 */
628 old_mode = inode->i_mode;
629 old_ino = inode->i_ino;
630 coda_vattr_to_iattr(inode, &attr);
631
632 if ((old_mode & S_IFMT) != (inode->i_mode & S_IFMT)) {
633 printk("Coda: inode %ld, fid %s changed type!\n",
634 inode->i_ino, coda_f2s(&(cii->c_fid)));
635 }
636
637 /* the following can happen when a local fid is replaced
638 with a global one, here we lose and declare the inode bad */
639 if (inode->i_ino != old_ino)
640 return -EIO;
641
642 coda_flag_inode_children(inode, C_FLUSH);
643
644 spin_lock(&cii->c_lock);
645 cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);
646 spin_unlock(&cii->c_lock);
647 }
648 return 0;
649 }
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