1 // SPDX-License-Identifier: GPL-2.0
2
3 /*
4 * Directory operations for Coda filesystem
5 * Original version: (C) 1996 P. Braam and M. Callahan
6 * Rewritten for Linux 2.1. (C) 1997 Carnegie Mellon University
7 *
8 * Carnegie Mellon encourages users to contribute improvements to
9 * the Coda project. Contact Peter Braam (coda@cs.cmu.edu).
10 */
11
12 #include <linux/types.h>
13 #include <linux/kernel.h>
14 #include <linux/time.h>
15 #include <linux/fs.h>
16 #include <linux/slab.h>
17 #include <linux/file.h>
18 #include <linux/stat.h>
19 #include <linux/errno.h>
20 #include <linux/string.h>
21 #include <linux/spinlock.h>
22 #include <linux/namei.h>
23 #include <linux/uaccess.h>
24
25 #include <linux/coda.h>
26 #include "coda_psdev.h"
27 #include "coda_linux.h"
28 #include "coda_cache.h"
29
30 #include "coda_int.h"
31
32 /* same as fs/bad_inode.c */
33 static int coda_return_EIO(void)
34 {
35 return -EIO;
36 }
37 #define CODA_EIO_ERROR ((void *) (coda_return_EIO))
38
39 /* inode operations for directories */
40 /* access routines: lookup, readlink, permission */
41 static struct dentry *coda_lookup(struct inode *dir, struct dentry *entry, unsigned int flags)
42 {
43 struct super_block *sb = dir->i_sb;
44 const char *name = entry->d_name.name;
45 size_t length = entry->d_name.len;
46 struct inode *inode;
47 int type = 0;
48
49 if (length > CODA_MAXNAMLEN) {
50 pr_err("name too long: lookup, %s %zu\n",
51 coda_i2s(dir), length);
52 return ERR_PTR(-ENAMETOOLONG);
53 }
54
55 /* control object, create inode on the fly */
56 if (is_root_inode(dir) && coda_iscontrol(name, length)) {
57 inode = coda_cnode_makectl(sb);
58 type = CODA_NOCACHE;
59 } else {
60 struct CodaFid fid = { { 0, } };
61 int error = venus_lookup(sb, coda_i2f(dir), name, length,
62 &type, &fid);
63 inode = !error ? coda_cnode_make(&fid, sb) : ERR_PTR(error);
64 }
65
66 if (!IS_ERR(inode) && (type & CODA_NOCACHE))
67 coda_flag_inode(inode, C_VATTR | C_PURGE);
68
69 if (inode == ERR_PTR(-ENOENT))
70 inode = NULL;
71
72 return d_splice_alias(inode, entry);
73 }
74
75
76 int coda_permission(struct mnt_idmap *idmap, struct inode *inode,
77 int mask)
78 {
79 int error;
80
81 if (mask & MAY_NOT_BLOCK)
82 return -ECHILD;
83
84 mask &= MAY_READ | MAY_WRITE | MAY_EXEC;
85
86 if (!mask)
87 return 0;
88
89 if ((mask & MAY_EXEC) && !execute_ok(inode))
90 return -EACCES;
91
92 if (coda_cache_check(inode, mask))
93 return 0;
94
95 error = venus_access(inode->i_sb, coda_i2f(inode), mask);
96
97 if (!error)
98 coda_cache_enter(inode, mask);
99
100 return error;
101 }
102
103
104 static inline void coda_dir_update_mtime(struct inode *dir)
105 {
106 #ifdef REQUERY_VENUS_FOR_MTIME
107 /* invalidate the directory cnode's attributes so we refetch the
108 * attributes from venus next time the inode is referenced */
109 coda_flag_inode(dir, C_VATTR);
110 #else
111 /* optimistically we can also act as if our nose bleeds. The
112 * granularity of the mtime is coarse anyways so we might actually be
113 * right most of the time. Note: we only do this for directories. */
114 inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
115 #endif
116 }
117
118 /* we have to wrap inc_nlink/drop_nlink because sometimes userspace uses a
119 * trick to fool GNU find's optimizations. If we can't be sure of the link
120 * (because of volume mount points) we set i_nlink to 1 which forces find
121 * to consider every child as a possible directory. We should also never
122 * see an increment or decrement for deleted directories where i_nlink == 0 */
123 static inline void coda_dir_inc_nlink(struct inode *dir)
124 {
125 if (dir->i_nlink >= 2)
126 inc_nlink(dir);
127 }
128
129 static inline void coda_dir_drop_nlink(struct inode *dir)
130 {
131 if (dir->i_nlink > 2)
132 drop_nlink(dir);
133 }
134
135 /* creation routines: create, mknod, mkdir, link, symlink */
136 static int coda_create(struct mnt_idmap *idmap, struct inode *dir,
137 struct dentry *de, umode_t mode, bool excl)
138 {
139 int error;
140 const char *name=de->d_name.name;
141 int length=de->d_name.len;
142 struct inode *inode;
143 struct CodaFid newfid;
144 struct coda_vattr attrs;
145
146 if (is_root_inode(dir) && coda_iscontrol(name, length))
147 return -EPERM;
148
149 error = venus_create(dir->i_sb, coda_i2f(dir), name, length,
150 0, mode, &newfid, &attrs);
151 if (error)
152 goto err_out;
153
154 inode = coda_iget(dir->i_sb, &newfid, &attrs);
155 if (IS_ERR(inode)) {
156 error = PTR_ERR(inode);
157 goto err_out;
158 }
159
160 /* invalidate the directory cnode's attributes */
161 coda_dir_update_mtime(dir);
162 d_instantiate(de, inode);
163 return 0;
164 err_out:
165 d_drop(de);
166 return error;
167 }
168
169 static int coda_mkdir(struct mnt_idmap *idmap, struct inode *dir,
170 struct dentry *de, umode_t mode)
171 {
172 struct inode *inode;
173 struct coda_vattr attrs;
174 const char *name = de->d_name.name;
175 int len = de->d_name.len;
176 int error;
177 struct CodaFid newfid;
178
179 if (is_root_inode(dir) && coda_iscontrol(name, len))
180 return -EPERM;
181
182 attrs.va_mode = mode;
183 error = venus_mkdir(dir->i_sb, coda_i2f(dir),
184 name, len, &newfid, &attrs);
185 if (error)
186 goto err_out;
187
188 inode = coda_iget(dir->i_sb, &newfid, &attrs);
189 if (IS_ERR(inode)) {
190 error = PTR_ERR(inode);
191 goto err_out;
192 }
193
194 /* invalidate the directory cnode's attributes */
195 coda_dir_inc_nlink(dir);
196 coda_dir_update_mtime(dir);
197 d_instantiate(de, inode);
198 return 0;
199 err_out:
200 d_drop(de);
201 return error;
202 }
203
204 /* try to make de an entry in dir_inodde linked to source_de */
205 static int coda_link(struct dentry *source_de, struct inode *dir_inode,
206 struct dentry *de)
207 {
208 struct inode *inode = d_inode(source_de);
209 const char * name = de->d_name.name;
210 int len = de->d_name.len;
211 int error;
212
213 if (is_root_inode(dir_inode) && coda_iscontrol(name, len))
214 return -EPERM;
215
216 error = venus_link(dir_inode->i_sb, coda_i2f(inode),
217 coda_i2f(dir_inode), (const char *)name, len);
218 if (error) {
219 d_drop(de);
220 return error;
221 }
222
223 coda_dir_update_mtime(dir_inode);
224 ihold(inode);
225 d_instantiate(de, inode);
226 inc_nlink(inode);
227 return 0;
228 }
229
230
231 static int coda_symlink(struct mnt_idmap *idmap,
232 struct inode *dir_inode, struct dentry *de,
233 const char *symname)
234 {
235 const char *name = de->d_name.name;
236 int len = de->d_name.len;
237 int symlen;
238 int error;
239
240 if (is_root_inode(dir_inode) && coda_iscontrol(name, len))
241 return -EPERM;
242
243 symlen = strlen(symname);
244 if (symlen > CODA_MAXPATHLEN)
245 return -ENAMETOOLONG;
246
247 /*
248 * This entry is now negative. Since we do not create
249 * an inode for the entry we have to drop it.
250 */
251 d_drop(de);
252 error = venus_symlink(dir_inode->i_sb, coda_i2f(dir_inode), name, len,
253 symname, symlen);
254
255 /* mtime is no good anymore */
256 if (!error)
257 coda_dir_update_mtime(dir_inode);
258
259 return error;
260 }
261
262 /* destruction routines: unlink, rmdir */
263 static int coda_unlink(struct inode *dir, struct dentry *de)
264 {
265 int error;
266 const char *name = de->d_name.name;
267 int len = de->d_name.len;
268
269 error = venus_remove(dir->i_sb, coda_i2f(dir), name, len);
270 if (error)
271 return error;
272
273 coda_dir_update_mtime(dir);
274 drop_nlink(d_inode(de));
275 return 0;
276 }
277
278 static int coda_rmdir(struct inode *dir, struct dentry *de)
279 {
280 const char *name = de->d_name.name;
281 int len = de->d_name.len;
282 int error;
283
284 error = venus_rmdir(dir->i_sb, coda_i2f(dir), name, len);
285 if (!error) {
286 /* VFS may delete the child */
287 if (d_really_is_positive(de))
288 clear_nlink(d_inode(de));
289
290 /* fix the link count of the parent */
291 coda_dir_drop_nlink(dir);
292 coda_dir_update_mtime(dir);
293 }
294 return error;
295 }
296
297 /* rename */
298 static int coda_rename(struct mnt_idmap *idmap, struct inode *old_dir,
299 struct dentry *old_dentry, struct inode *new_dir,
300 struct dentry *new_dentry, unsigned int flags)
301 {
302 const char *old_name = old_dentry->d_name.name;
303 const char *new_name = new_dentry->d_name.name;
304 int old_length = old_dentry->d_name.len;
305 int new_length = new_dentry->d_name.len;
306 int error;
307
308 if (flags)
309 return -EINVAL;
310
311 error = venus_rename(old_dir->i_sb, coda_i2f(old_dir),
312 coda_i2f(new_dir), old_length, new_length,
313 (const char *) old_name, (const char *)new_name);
314 if (!error) {
315 if (d_really_is_positive(new_dentry)) {
316 if (d_is_dir(new_dentry)) {
317 coda_dir_drop_nlink(old_dir);
318 coda_dir_inc_nlink(new_dir);
319 }
320 coda_flag_inode(d_inode(new_dentry), C_VATTR);
321 }
322 coda_dir_update_mtime(old_dir);
323 coda_dir_update_mtime(new_dir);
324 }
325 return error;
326 }
327
328 static inline unsigned int CDT2DT(unsigned char cdt)
329 {
330 unsigned int dt;
331
332 switch(cdt) {
333 case CDT_UNKNOWN: dt = DT_UNKNOWN; break;
334 case CDT_FIFO: dt = DT_FIFO; break;
335 case CDT_CHR: dt = DT_CHR; break;
336 case CDT_DIR: dt = DT_DIR; break;
337 case CDT_BLK: dt = DT_BLK; break;
338 case CDT_REG: dt = DT_REG; break;
339 case CDT_LNK: dt = DT_LNK; break;
340 case CDT_SOCK: dt = DT_SOCK; break;
341 case CDT_WHT: dt = DT_WHT; break;
342 default: dt = DT_UNKNOWN; break;
343 }
344 return dt;
345 }
346
347 /* support routines */
348 static int coda_venus_readdir(struct file *coda_file, struct dir_context *ctx)
349 {
350 struct coda_file_info *cfi;
351 struct coda_inode_info *cii;
352 struct file *host_file;
353 struct venus_dirent *vdir;
354 unsigned long vdir_size = offsetof(struct venus_dirent, d_name);
355 unsigned int type;
356 struct qstr name;
357 ino_t ino;
358 int ret;
359
360 cfi = coda_ftoc(coda_file);
361 host_file = cfi->cfi_container;
362
363 cii = ITOC(file_inode(coda_file));
364
365 vdir = kmalloc(sizeof(*vdir), GFP_KERNEL);
366 if (!vdir) return -ENOMEM;
367
368 if (!dir_emit_dots(coda_file, ctx))
369 goto out;
370
371 while (1) {
372 loff_t pos = ctx->pos - 2;
373
374 /* read entries from the directory file */
375 ret = kernel_read(host_file, vdir, sizeof(*vdir), &pos);
376 if (ret < 0) {
377 pr_err("%s: read dir %s failed %d\n",
378 __func__, coda_f2s(&cii->c_fid), ret);
379 break;
380 }
381 if (ret == 0) break; /* end of directory file reached */
382
383 /* catch truncated reads */
384 if (ret < vdir_size || ret < vdir_size + vdir->d_namlen) {
385 pr_err("%s: short read on %s\n",
386 __func__, coda_f2s(&cii->c_fid));
387 ret = -EBADF;
388 break;
389 }
390 /* validate whether the directory file actually makes sense */
391 if (vdir->d_reclen < vdir_size + vdir->d_namlen) {
392 pr_err("%s: invalid dir %s\n",
393 __func__, coda_f2s(&cii->c_fid));
394 ret = -EBADF;
395 break;
396 }
397
398 name.len = vdir->d_namlen;
399 name.name = vdir->d_name;
400
401 /* Make sure we skip '.' and '..', we already got those */
402 if (name.name[0] == '.' && (name.len == 1 ||
403 (name.name[1] == '.' && name.len == 2)))
404 vdir->d_fileno = name.len = 0;
405
406 /* skip null entries */
407 if (vdir->d_fileno && name.len) {
408 ino = vdir->d_fileno;
409 type = CDT2DT(vdir->d_type);
410 if (!dir_emit(ctx, name.name, name.len, ino, type))
411 break;
412 }
413 /* we'll always have progress because d_reclen is unsigned and
414 * we've already established it is non-zero. */
415 ctx->pos += vdir->d_reclen;
416 }
417 out:
418 kfree(vdir);
419 return 0;
420 }
421
422 /* file operations for directories */
423 static int coda_readdir(struct file *coda_file, struct dir_context *ctx)
424 {
425 struct coda_file_info *cfi;
426 struct file *host_file;
427 int ret;
428
429 cfi = coda_ftoc(coda_file);
430 host_file = cfi->cfi_container;
431
432 if (host_file->f_op->iterate_shared) {
433 struct inode *host_inode = file_inode(host_file);
434 ret = -ENOENT;
435 if (!IS_DEADDIR(host_inode)) {
436 inode_lock_shared(host_inode);
437 ret = host_file->f_op->iterate_shared(host_file, ctx);
438 file_accessed(host_file);
439 inode_unlock_shared(host_inode);
440 }
441 return ret;
442 }
443 /* Venus: we must read Venus dirents from a file */
444 return coda_venus_readdir(coda_file, ctx);
445 }
446
447 /* called when a cache lookup succeeds */
448 static int coda_dentry_revalidate(struct dentry *de, unsigned int flags)
449 {
450 struct inode *inode;
451 struct coda_inode_info *cii;
452
453 if (flags & LOOKUP_RCU)
454 return -ECHILD;
455
456 inode = d_inode(de);
457 if (!inode || is_root_inode(inode))
458 goto out;
459 if (is_bad_inode(inode))
460 goto bad;
461
462 cii = ITOC(d_inode(de));
463 if (!(cii->c_flags & (C_PURGE | C_FLUSH)))
464 goto out;
465
466 shrink_dcache_parent(de);
467
468 /* propagate for a flush */
469 if (cii->c_flags & C_FLUSH)
470 coda_flag_inode_children(inode, C_FLUSH);
471
472 if (d_count(de) > 1)
473 /* pretend it's valid, but don't change the flags */
474 goto out;
475
476 /* clear the flags. */
477 spin_lock(&cii->c_lock);
478 cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);
479 spin_unlock(&cii->c_lock);
480 bad:
481 return 0;
482 out:
483 return 1;
484 }
485
486 /*
487 * This is the callback from dput() when d_count is going to 0.
488 * We use this to unhash dentries with bad inodes.
489 */
490 static int coda_dentry_delete(const struct dentry * dentry)
491 {
492 struct inode *inode;
493 struct coda_inode_info *cii;
494
495 if (d_really_is_negative(dentry))
496 return 0;
497
498 inode = d_inode(dentry);
499 if (!inode || is_bad_inode(inode))
500 return 1;
501
502 cii = ITOC(inode);
503 if (cii->c_flags & C_PURGE)
504 return 1;
505
506 return 0;
507 }
508
509
510
511 /*
512 * This is called when we want to check if the inode has
513 * changed on the server. Coda makes this easy since the
514 * cache manager Venus issues a downcall to the kernel when this
515 * happens
516 */
517 int coda_revalidate_inode(struct inode *inode)
518 {
519 struct coda_vattr attr;
520 int error;
521 int old_mode;
522 ino_t old_ino;
523 struct coda_inode_info *cii = ITOC(inode);
524
525 if (!cii->c_flags)
526 return 0;
527
528 if (cii->c_flags & (C_VATTR | C_PURGE | C_FLUSH)) {
529 error = venus_getattr(inode->i_sb, &(cii->c_fid), &attr);
530 if (error)
531 return -EIO;
532
533 /* this inode may be lost if:
534 - it's ino changed
535 - type changes must be permitted for repair and
536 missing mount points.
537 */
538 old_mode = inode->i_mode;
539 old_ino = inode->i_ino;
540 coda_vattr_to_iattr(inode, &attr);
541
542 if ((old_mode & S_IFMT) != (inode->i_mode & S_IFMT)) {
543 pr_warn("inode %ld, fid %s changed type!\n",
544 inode->i_ino, coda_f2s(&(cii->c_fid)));
545 }
546
547 /* the following can happen when a local fid is replaced
548 with a global one, here we lose and declare the inode bad */
549 if (inode->i_ino != old_ino)
550 return -EIO;
551
552 coda_flag_inode_children(inode, C_FLUSH);
553
554 spin_lock(&cii->c_lock);
555 cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);
556 spin_unlock(&cii->c_lock);
557 }
558 return 0;
559 }
560
561 const struct dentry_operations coda_dentry_operations = {
562 .d_revalidate = coda_dentry_revalidate,
563 .d_delete = coda_dentry_delete,
564 };
565
566 const struct inode_operations coda_dir_inode_operations = {
567 .create = coda_create,
568 .lookup = coda_lookup,
569 .link = coda_link,
570 .unlink = coda_unlink,
571 .symlink = coda_symlink,
572 .mkdir = coda_mkdir,
573 .rmdir = coda_rmdir,
574 .mknod = CODA_EIO_ERROR,
575 .rename = coda_rename,
576 .permission = coda_permission,
577 .getattr = coda_getattr,
578 .setattr = coda_setattr,
579 };
580
581 WRAP_DIR_ITER(coda_readdir) // FIXME!
582 const struct file_operations coda_dir_operations = {
583 .llseek = generic_file_llseek,
584 .read = generic_read_dir,
585 .iterate_shared = shared_coda_readdir,
586 .open = coda_open,
587 .release = coda_release,
588 .fsync = coda_fsync,
589 };
590
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