Commit | Line | Data |
---|---|---|
e9be9d5e MS |
1 | /* |
2 | * | |
3 | * Copyright (C) 2011 Novell Inc. | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify it | |
6 | * under the terms of the GNU General Public License version 2 as published by | |
7 | * the Free Software Foundation. | |
8 | */ | |
9 | ||
10 | #include <linux/fs.h> | |
11 | #include <linux/slab.h> | |
12 | #include <linux/namei.h> | |
13 | #include <linux/file.h> | |
14 | #include <linux/xattr.h> | |
15 | #include <linux/rbtree.h> | |
16 | #include <linux/security.h> | |
17 | #include <linux/cred.h> | |
18 | #include "overlayfs.h" | |
19 | ||
20 | struct ovl_cache_entry { | |
e9be9d5e MS |
21 | unsigned int len; |
22 | unsigned int type; | |
23 | u64 ino; | |
e9be9d5e MS |
24 | struct list_head l_node; |
25 | struct rb_node node; | |
cdb67279 | 26 | struct ovl_cache_entry *next_maybe_whiteout; |
c2096537 | 27 | bool is_whiteout; |
68bf8611 | 28 | char name[]; |
e9be9d5e MS |
29 | }; |
30 | ||
31 | struct ovl_dir_cache { | |
32 | long refcount; | |
33 | u64 version; | |
34 | struct list_head entries; | |
35 | }; | |
36 | ||
37 | struct ovl_readdir_data { | |
38 | struct dir_context ctx; | |
56656e96 | 39 | bool is_lowest; |
49be4fb9 | 40 | struct rb_root root; |
e9be9d5e | 41 | struct list_head *list; |
db6ec212 | 42 | struct list_head middle; |
cdb67279 | 43 | struct ovl_cache_entry *first_maybe_whiteout; |
e9be9d5e MS |
44 | int count; |
45 | int err; | |
45aebeaf | 46 | bool d_type_supported; |
e9be9d5e MS |
47 | }; |
48 | ||
49 | struct ovl_dir_file { | |
50 | bool is_real; | |
51 | bool is_upper; | |
52 | struct ovl_dir_cache *cache; | |
4330397e | 53 | struct list_head *cursor; |
e9be9d5e MS |
54 | struct file *realfile; |
55 | struct file *upperfile; | |
56 | }; | |
57 | ||
58 | static struct ovl_cache_entry *ovl_cache_entry_from_node(struct rb_node *n) | |
59 | { | |
60 | return container_of(n, struct ovl_cache_entry, node); | |
61 | } | |
62 | ||
63 | static struct ovl_cache_entry *ovl_cache_entry_find(struct rb_root *root, | |
64 | const char *name, int len) | |
65 | { | |
66 | struct rb_node *node = root->rb_node; | |
67 | int cmp; | |
68 | ||
69 | while (node) { | |
70 | struct ovl_cache_entry *p = ovl_cache_entry_from_node(node); | |
71 | ||
72 | cmp = strncmp(name, p->name, len); | |
73 | if (cmp > 0) | |
74 | node = p->node.rb_right; | |
75 | else if (cmp < 0 || len < p->len) | |
76 | node = p->node.rb_left; | |
77 | else | |
78 | return p; | |
79 | } | |
80 | ||
81 | return NULL; | |
82 | } | |
83 | ||
cdb67279 | 84 | static struct ovl_cache_entry *ovl_cache_entry_new(struct ovl_readdir_data *rdd, |
3e01cee3 | 85 | const char *name, int len, |
e9be9d5e MS |
86 | u64 ino, unsigned int d_type) |
87 | { | |
88 | struct ovl_cache_entry *p; | |
68bf8611 | 89 | size_t size = offsetof(struct ovl_cache_entry, name[len + 1]); |
e9be9d5e | 90 | |
68bf8611 | 91 | p = kmalloc(size, GFP_KERNEL); |
3e01cee3 MS |
92 | if (!p) |
93 | return NULL; | |
94 | ||
95 | memcpy(p->name, name, len); | |
96 | p->name[len] = '\0'; | |
97 | p->len = len; | |
98 | p->type = d_type; | |
99 | p->ino = ino; | |
100 | p->is_whiteout = false; | |
3e01cee3 MS |
101 | |
102 | if (d_type == DT_CHR) { | |
cdb67279 MS |
103 | p->next_maybe_whiteout = rdd->first_maybe_whiteout; |
104 | rdd->first_maybe_whiteout = p; | |
3e01cee3 | 105 | } |
e9be9d5e MS |
106 | return p; |
107 | } | |
108 | ||
109 | static int ovl_cache_entry_add_rb(struct ovl_readdir_data *rdd, | |
110 | const char *name, int len, u64 ino, | |
111 | unsigned int d_type) | |
112 | { | |
49be4fb9 | 113 | struct rb_node **newp = &rdd->root.rb_node; |
e9be9d5e MS |
114 | struct rb_node *parent = NULL; |
115 | struct ovl_cache_entry *p; | |
116 | ||
117 | while (*newp) { | |
118 | int cmp; | |
119 | struct ovl_cache_entry *tmp; | |
120 | ||
121 | parent = *newp; | |
122 | tmp = ovl_cache_entry_from_node(*newp); | |
123 | cmp = strncmp(name, tmp->name, len); | |
124 | if (cmp > 0) | |
125 | newp = &tmp->node.rb_right; | |
126 | else if (cmp < 0 || len < tmp->len) | |
127 | newp = &tmp->node.rb_left; | |
128 | else | |
129 | return 0; | |
130 | } | |
131 | ||
cdb67279 | 132 | p = ovl_cache_entry_new(rdd, name, len, ino, d_type); |
e9be9d5e MS |
133 | if (p == NULL) |
134 | return -ENOMEM; | |
135 | ||
136 | list_add_tail(&p->l_node, rdd->list); | |
137 | rb_link_node(&p->node, parent, newp); | |
49be4fb9 | 138 | rb_insert_color(&p->node, &rdd->root); |
e9be9d5e MS |
139 | |
140 | return 0; | |
141 | } | |
142 | ||
56656e96 MS |
143 | static int ovl_fill_lowest(struct ovl_readdir_data *rdd, |
144 | const char *name, int namelen, | |
145 | loff_t offset, u64 ino, unsigned int d_type) | |
e9be9d5e MS |
146 | { |
147 | struct ovl_cache_entry *p; | |
148 | ||
49be4fb9 | 149 | p = ovl_cache_entry_find(&rdd->root, name, namelen); |
e9be9d5e | 150 | if (p) { |
db6ec212 | 151 | list_move_tail(&p->l_node, &rdd->middle); |
e9be9d5e | 152 | } else { |
cdb67279 | 153 | p = ovl_cache_entry_new(rdd, name, namelen, ino, d_type); |
e9be9d5e MS |
154 | if (p == NULL) |
155 | rdd->err = -ENOMEM; | |
156 | else | |
db6ec212 | 157 | list_add_tail(&p->l_node, &rdd->middle); |
e9be9d5e MS |
158 | } |
159 | ||
160 | return rdd->err; | |
161 | } | |
162 | ||
163 | void ovl_cache_free(struct list_head *list) | |
164 | { | |
165 | struct ovl_cache_entry *p; | |
166 | struct ovl_cache_entry *n; | |
167 | ||
168 | list_for_each_entry_safe(p, n, list, l_node) | |
169 | kfree(p); | |
170 | ||
171 | INIT_LIST_HEAD(list); | |
172 | } | |
173 | ||
174 | static void ovl_cache_put(struct ovl_dir_file *od, struct dentry *dentry) | |
175 | { | |
176 | struct ovl_dir_cache *cache = od->cache; | |
177 | ||
e9be9d5e MS |
178 | WARN_ON(cache->refcount <= 0); |
179 | cache->refcount--; | |
180 | if (!cache->refcount) { | |
181 | if (ovl_dir_cache(dentry) == cache) | |
182 | ovl_set_dir_cache(dentry, NULL); | |
183 | ||
184 | ovl_cache_free(&cache->entries); | |
185 | kfree(cache); | |
186 | } | |
187 | } | |
188 | ||
ac7576f4 MS |
189 | static int ovl_fill_merge(struct dir_context *ctx, const char *name, |
190 | int namelen, loff_t offset, u64 ino, | |
191 | unsigned int d_type) | |
e9be9d5e | 192 | { |
ac7576f4 MS |
193 | struct ovl_readdir_data *rdd = |
194 | container_of(ctx, struct ovl_readdir_data, ctx); | |
e9be9d5e MS |
195 | |
196 | rdd->count++; | |
56656e96 | 197 | if (!rdd->is_lowest) |
e9be9d5e MS |
198 | return ovl_cache_entry_add_rb(rdd, name, namelen, ino, d_type); |
199 | else | |
56656e96 | 200 | return ovl_fill_lowest(rdd, name, namelen, offset, ino, d_type); |
e9be9d5e MS |
201 | } |
202 | ||
cdb67279 MS |
203 | static int ovl_check_whiteouts(struct dentry *dir, struct ovl_readdir_data *rdd) |
204 | { | |
205 | int err; | |
206 | struct ovl_cache_entry *p; | |
207 | struct dentry *dentry; | |
208 | const struct cred *old_cred; | |
209 | struct cred *override_cred; | |
210 | ||
211 | override_cred = prepare_creds(); | |
212 | if (!override_cred) | |
213 | return -ENOMEM; | |
214 | ||
215 | /* | |
216 | * CAP_DAC_OVERRIDE for lookup | |
217 | */ | |
218 | cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE); | |
219 | old_cred = override_creds(override_cred); | |
220 | ||
221 | err = mutex_lock_killable(&dir->d_inode->i_mutex); | |
222 | if (!err) { | |
223 | while (rdd->first_maybe_whiteout) { | |
224 | p = rdd->first_maybe_whiteout; | |
225 | rdd->first_maybe_whiteout = p->next_maybe_whiteout; | |
226 | dentry = lookup_one_len(p->name, dir, p->len); | |
227 | if (!IS_ERR(dentry)) { | |
228 | p->is_whiteout = ovl_is_whiteout(dentry); | |
229 | dput(dentry); | |
230 | } | |
231 | } | |
5955102c | 232 | inode_unlock(dir->d_inode); |
cdb67279 MS |
233 | } |
234 | revert_creds(old_cred); | |
235 | put_cred(override_cred); | |
236 | ||
237 | return err; | |
238 | } | |
239 | ||
e9be9d5e MS |
240 | static inline int ovl_dir_read(struct path *realpath, |
241 | struct ovl_readdir_data *rdd) | |
242 | { | |
243 | struct file *realfile; | |
244 | int err; | |
245 | ||
246 | realfile = ovl_path_open(realpath, O_RDONLY | O_DIRECTORY); | |
247 | if (IS_ERR(realfile)) | |
248 | return PTR_ERR(realfile); | |
249 | ||
cdb67279 | 250 | rdd->first_maybe_whiteout = NULL; |
e9be9d5e MS |
251 | rdd->ctx.pos = 0; |
252 | do { | |
253 | rdd->count = 0; | |
254 | rdd->err = 0; | |
255 | err = iterate_dir(realfile, &rdd->ctx); | |
256 | if (err >= 0) | |
257 | err = rdd->err; | |
258 | } while (!err && rdd->count); | |
cdb67279 MS |
259 | |
260 | if (!err && rdd->first_maybe_whiteout) | |
261 | err = ovl_check_whiteouts(realpath->dentry, rdd); | |
262 | ||
e9be9d5e MS |
263 | fput(realfile); |
264 | ||
265 | return err; | |
266 | } | |
267 | ||
268 | static void ovl_dir_reset(struct file *file) | |
269 | { | |
270 | struct ovl_dir_file *od = file->private_data; | |
271 | struct ovl_dir_cache *cache = od->cache; | |
272 | struct dentry *dentry = file->f_path.dentry; | |
273 | enum ovl_path_type type = ovl_path_type(dentry); | |
274 | ||
275 | if (cache && ovl_dentry_version_get(dentry) != cache->version) { | |
276 | ovl_cache_put(od, dentry); | |
277 | od->cache = NULL; | |
4330397e | 278 | od->cursor = NULL; |
e9be9d5e | 279 | } |
1afaba1e MS |
280 | WARN_ON(!od->is_real && !OVL_TYPE_MERGE(type)); |
281 | if (od->is_real && OVL_TYPE_MERGE(type)) | |
e9be9d5e MS |
282 | od->is_real = false; |
283 | } | |
284 | ||
c9f00fdb | 285 | static int ovl_dir_read_merged(struct dentry *dentry, struct list_head *list) |
e9be9d5e MS |
286 | { |
287 | int err; | |
9d7459d8 | 288 | struct path realpath; |
e9be9d5e MS |
289 | struct ovl_readdir_data rdd = { |
290 | .ctx.actor = ovl_fill_merge, | |
291 | .list = list, | |
49be4fb9 | 292 | .root = RB_ROOT, |
56656e96 | 293 | .is_lowest = false, |
e9be9d5e | 294 | }; |
9d7459d8 | 295 | int idx, next; |
e9be9d5e | 296 | |
9d7459d8 MS |
297 | for (idx = 0; idx != -1; idx = next) { |
298 | next = ovl_path_next(idx, dentry, &realpath); | |
c9f00fdb | 299 | |
9d7459d8 | 300 | if (next != -1) { |
9d7459d8 | 301 | err = ovl_dir_read(&realpath, &rdd); |
e9be9d5e | 302 | if (err) |
9d7459d8 MS |
303 | break; |
304 | } else { | |
305 | /* | |
306 | * Insert lowest layer entries before upper ones, this | |
307 | * allows offsets to be reasonably constant | |
308 | */ | |
309 | list_add(&rdd.middle, rdd.list); | |
56656e96 | 310 | rdd.is_lowest = true; |
9d7459d8 MS |
311 | err = ovl_dir_read(&realpath, &rdd); |
312 | list_del(&rdd.middle); | |
e9be9d5e MS |
313 | } |
314 | } | |
e9be9d5e | 315 | return err; |
e9be9d5e MS |
316 | } |
317 | ||
318 | static void ovl_seek_cursor(struct ovl_dir_file *od, loff_t pos) | |
319 | { | |
4330397e | 320 | struct list_head *p; |
e9be9d5e MS |
321 | loff_t off = 0; |
322 | ||
4330397e | 323 | list_for_each(p, &od->cache->entries) { |
e9be9d5e MS |
324 | if (off >= pos) |
325 | break; | |
326 | off++; | |
327 | } | |
4330397e | 328 | /* Cursor is safe since the cache is stable */ |
329 | od->cursor = p; | |
e9be9d5e MS |
330 | } |
331 | ||
332 | static struct ovl_dir_cache *ovl_cache_get(struct dentry *dentry) | |
333 | { | |
334 | int res; | |
e9be9d5e MS |
335 | struct ovl_dir_cache *cache; |
336 | ||
337 | cache = ovl_dir_cache(dentry); | |
338 | if (cache && ovl_dentry_version_get(dentry) == cache->version) { | |
339 | cache->refcount++; | |
340 | return cache; | |
341 | } | |
342 | ovl_set_dir_cache(dentry, NULL); | |
343 | ||
344 | cache = kzalloc(sizeof(struct ovl_dir_cache), GFP_KERNEL); | |
345 | if (!cache) | |
346 | return ERR_PTR(-ENOMEM); | |
347 | ||
348 | cache->refcount = 1; | |
349 | INIT_LIST_HEAD(&cache->entries); | |
350 | ||
c9f00fdb | 351 | res = ovl_dir_read_merged(dentry, &cache->entries); |
e9be9d5e MS |
352 | if (res) { |
353 | ovl_cache_free(&cache->entries); | |
354 | kfree(cache); | |
355 | return ERR_PTR(res); | |
356 | } | |
357 | ||
358 | cache->version = ovl_dentry_version_get(dentry); | |
359 | ovl_set_dir_cache(dentry, cache); | |
360 | ||
361 | return cache; | |
362 | } | |
363 | ||
364 | static int ovl_iterate(struct file *file, struct dir_context *ctx) | |
365 | { | |
366 | struct ovl_dir_file *od = file->private_data; | |
367 | struct dentry *dentry = file->f_path.dentry; | |
4330397e | 368 | struct ovl_cache_entry *p; |
e9be9d5e MS |
369 | |
370 | if (!ctx->pos) | |
371 | ovl_dir_reset(file); | |
372 | ||
373 | if (od->is_real) | |
374 | return iterate_dir(od->realfile, ctx); | |
375 | ||
376 | if (!od->cache) { | |
377 | struct ovl_dir_cache *cache; | |
378 | ||
379 | cache = ovl_cache_get(dentry); | |
380 | if (IS_ERR(cache)) | |
381 | return PTR_ERR(cache); | |
382 | ||
383 | od->cache = cache; | |
384 | ovl_seek_cursor(od, ctx->pos); | |
385 | } | |
386 | ||
4330397e | 387 | while (od->cursor != &od->cache->entries) { |
388 | p = list_entry(od->cursor, struct ovl_cache_entry, l_node); | |
389 | if (!p->is_whiteout) | |
390 | if (!dir_emit(ctx, p->name, p->len, p->ino, p->type)) | |
391 | break; | |
392 | od->cursor = p->l_node.next; | |
393 | ctx->pos++; | |
e9be9d5e MS |
394 | } |
395 | return 0; | |
396 | } | |
397 | ||
398 | static loff_t ovl_dir_llseek(struct file *file, loff_t offset, int origin) | |
399 | { | |
400 | loff_t res; | |
401 | struct ovl_dir_file *od = file->private_data; | |
402 | ||
5955102c | 403 | inode_lock(file_inode(file)); |
e9be9d5e MS |
404 | if (!file->f_pos) |
405 | ovl_dir_reset(file); | |
406 | ||
407 | if (od->is_real) { | |
408 | res = vfs_llseek(od->realfile, offset, origin); | |
409 | file->f_pos = od->realfile->f_pos; | |
410 | } else { | |
411 | res = -EINVAL; | |
412 | ||
413 | switch (origin) { | |
414 | case SEEK_CUR: | |
415 | offset += file->f_pos; | |
416 | break; | |
417 | case SEEK_SET: | |
418 | break; | |
419 | default: | |
420 | goto out_unlock; | |
421 | } | |
422 | if (offset < 0) | |
423 | goto out_unlock; | |
424 | ||
425 | if (offset != file->f_pos) { | |
426 | file->f_pos = offset; | |
427 | if (od->cache) | |
428 | ovl_seek_cursor(od, offset); | |
429 | } | |
430 | res = offset; | |
431 | } | |
432 | out_unlock: | |
5955102c | 433 | inode_unlock(file_inode(file)); |
e9be9d5e MS |
434 | |
435 | return res; | |
436 | } | |
437 | ||
438 | static int ovl_dir_fsync(struct file *file, loff_t start, loff_t end, | |
439 | int datasync) | |
440 | { | |
441 | struct ovl_dir_file *od = file->private_data; | |
442 | struct dentry *dentry = file->f_path.dentry; | |
443 | struct file *realfile = od->realfile; | |
444 | ||
445 | /* | |
446 | * Need to check if we started out being a lower dir, but got copied up | |
447 | */ | |
1afaba1e | 448 | if (!od->is_upper && OVL_TYPE_UPPER(ovl_path_type(dentry))) { |
e9be9d5e MS |
449 | struct inode *inode = file_inode(file); |
450 | ||
7676895f | 451 | realfile = lockless_dereference(od->upperfile); |
e9be9d5e MS |
452 | if (!realfile) { |
453 | struct path upperpath; | |
454 | ||
455 | ovl_path_upper(dentry, &upperpath); | |
456 | realfile = ovl_path_open(&upperpath, O_RDONLY); | |
d45f00ae | 457 | smp_mb__before_spinlock(); |
5955102c | 458 | inode_lock(inode); |
3d268c9b AV |
459 | if (!od->upperfile) { |
460 | if (IS_ERR(realfile)) { | |
5955102c | 461 | inode_unlock(inode); |
3d268c9b AV |
462 | return PTR_ERR(realfile); |
463 | } | |
464 | od->upperfile = realfile; | |
465 | } else { | |
466 | /* somebody has beaten us to it */ | |
467 | if (!IS_ERR(realfile)) | |
468 | fput(realfile); | |
469 | realfile = od->upperfile; | |
e9be9d5e | 470 | } |
5955102c | 471 | inode_unlock(inode); |
e9be9d5e | 472 | } |
e9be9d5e MS |
473 | } |
474 | ||
475 | return vfs_fsync_range(realfile, start, end, datasync); | |
476 | } | |
477 | ||
478 | static int ovl_dir_release(struct inode *inode, struct file *file) | |
479 | { | |
480 | struct ovl_dir_file *od = file->private_data; | |
481 | ||
482 | if (od->cache) { | |
5955102c | 483 | inode_lock(inode); |
e9be9d5e | 484 | ovl_cache_put(od, file->f_path.dentry); |
5955102c | 485 | inode_unlock(inode); |
e9be9d5e MS |
486 | } |
487 | fput(od->realfile); | |
488 | if (od->upperfile) | |
489 | fput(od->upperfile); | |
490 | kfree(od); | |
491 | ||
492 | return 0; | |
493 | } | |
494 | ||
495 | static int ovl_dir_open(struct inode *inode, struct file *file) | |
496 | { | |
497 | struct path realpath; | |
498 | struct file *realfile; | |
499 | struct ovl_dir_file *od; | |
500 | enum ovl_path_type type; | |
501 | ||
502 | od = kzalloc(sizeof(struct ovl_dir_file), GFP_KERNEL); | |
503 | if (!od) | |
504 | return -ENOMEM; | |
505 | ||
506 | type = ovl_path_real(file->f_path.dentry, &realpath); | |
507 | realfile = ovl_path_open(&realpath, file->f_flags); | |
508 | if (IS_ERR(realfile)) { | |
509 | kfree(od); | |
510 | return PTR_ERR(realfile); | |
511 | } | |
e9be9d5e | 512 | od->realfile = realfile; |
1afaba1e MS |
513 | od->is_real = !OVL_TYPE_MERGE(type); |
514 | od->is_upper = OVL_TYPE_UPPER(type); | |
e9be9d5e MS |
515 | file->private_data = od; |
516 | ||
517 | return 0; | |
518 | } | |
519 | ||
520 | const struct file_operations ovl_dir_operations = { | |
521 | .read = generic_read_dir, | |
522 | .open = ovl_dir_open, | |
523 | .iterate = ovl_iterate, | |
524 | .llseek = ovl_dir_llseek, | |
525 | .fsync = ovl_dir_fsync, | |
526 | .release = ovl_dir_release, | |
527 | }; | |
528 | ||
529 | int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list) | |
530 | { | |
531 | int err; | |
e9be9d5e MS |
532 | struct ovl_cache_entry *p; |
533 | ||
c9f00fdb | 534 | err = ovl_dir_read_merged(dentry, list); |
e9be9d5e MS |
535 | if (err) |
536 | return err; | |
537 | ||
538 | err = 0; | |
539 | ||
540 | list_for_each_entry(p, list, l_node) { | |
541 | if (p->is_whiteout) | |
542 | continue; | |
543 | ||
544 | if (p->name[0] == '.') { | |
545 | if (p->len == 1) | |
546 | continue; | |
547 | if (p->len == 2 && p->name[1] == '.') | |
548 | continue; | |
549 | } | |
550 | err = -ENOTEMPTY; | |
551 | break; | |
552 | } | |
553 | ||
554 | return err; | |
555 | } | |
556 | ||
557 | void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list) | |
558 | { | |
559 | struct ovl_cache_entry *p; | |
560 | ||
5955102c | 561 | inode_lock_nested(upper->d_inode, I_MUTEX_CHILD); |
e9be9d5e MS |
562 | list_for_each_entry(p, list, l_node) { |
563 | struct dentry *dentry; | |
564 | ||
565 | if (!p->is_whiteout) | |
566 | continue; | |
567 | ||
568 | dentry = lookup_one_len(p->name, upper, p->len); | |
569 | if (IS_ERR(dentry)) { | |
570 | pr_err("overlayfs: lookup '%s/%.*s' failed (%i)\n", | |
571 | upper->d_name.name, p->len, p->name, | |
572 | (int) PTR_ERR(dentry)); | |
573 | continue; | |
574 | } | |
84889d49 KK |
575 | if (dentry->d_inode) |
576 | ovl_cleanup(upper->d_inode, dentry); | |
e9be9d5e MS |
577 | dput(dentry); |
578 | } | |
5955102c | 579 | inode_unlock(upper->d_inode); |
e9be9d5e | 580 | } |
45aebeaf VG |
581 | |
582 | static int ovl_check_d_type(struct dir_context *ctx, const char *name, | |
583 | int namelen, loff_t offset, u64 ino, | |
584 | unsigned int d_type) | |
585 | { | |
586 | struct ovl_readdir_data *rdd = | |
587 | container_of(ctx, struct ovl_readdir_data, ctx); | |
588 | ||
589 | /* Even if d_type is not supported, DT_DIR is returned for . and .. */ | |
590 | if (!strncmp(name, ".", namelen) || !strncmp(name, "..", namelen)) | |
591 | return 0; | |
592 | ||
593 | if (d_type != DT_UNKNOWN) | |
594 | rdd->d_type_supported = true; | |
595 | ||
596 | return 0; | |
597 | } | |
598 | ||
599 | /* | |
600 | * Returns 1 if d_type is supported, 0 not supported/unknown. Negative values | |
601 | * if error is encountered. | |
602 | */ | |
603 | int ovl_check_d_type_supported(struct path *realpath) | |
604 | { | |
605 | int err; | |
606 | struct ovl_readdir_data rdd = { | |
607 | .ctx.actor = ovl_check_d_type, | |
608 | .d_type_supported = false, | |
609 | }; | |
610 | ||
611 | err = ovl_dir_read(realpath, &rdd); | |
612 | if (err) | |
613 | return err; | |
614 | ||
615 | return rdd.d_type_supported; | |
616 | } |