Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * fs/dcache.c | |
3 | * | |
4 | * Complete reimplementation | |
5 | * (C) 1997 Thomas Schoebel-Theuer, | |
6 | * with heavy changes by Linus Torvalds | |
7 | */ | |
8 | ||
9 | /* | |
10 | * Notes on the allocation strategy: | |
11 | * | |
12 | * The dcache is a master of the icache - whenever a dcache entry | |
13 | * exists, the inode will always exist. "iput()" is done either when | |
14 | * the dcache entry is deleted or garbage collected. | |
15 | */ | |
16 | ||
1da177e4 LT |
17 | #include <linux/syscalls.h> |
18 | #include <linux/string.h> | |
19 | #include <linux/mm.h> | |
31f3e0b3 | 20 | #include <linux/fdtable.h> |
1da177e4 | 21 | #include <linux/fs.h> |
7a91bf7f | 22 | #include <linux/fsnotify.h> |
1da177e4 LT |
23 | #include <linux/slab.h> |
24 | #include <linux/init.h> | |
1da177e4 LT |
25 | #include <linux/hash.h> |
26 | #include <linux/cache.h> | |
27 | #include <linux/module.h> | |
28 | #include <linux/mount.h> | |
29 | #include <linux/file.h> | |
30 | #include <asm/uaccess.h> | |
31 | #include <linux/security.h> | |
32 | #include <linux/seqlock.h> | |
33 | #include <linux/swap.h> | |
34 | #include <linux/bootmem.h> | |
07f3f05c | 35 | #include "internal.h" |
1da177e4 | 36 | |
1da177e4 | 37 | |
fa3536cc | 38 | int sysctl_vfs_cache_pressure __read_mostly = 100; |
1da177e4 LT |
39 | EXPORT_SYMBOL_GPL(sysctl_vfs_cache_pressure); |
40 | ||
41 | __cacheline_aligned_in_smp DEFINE_SPINLOCK(dcache_lock); | |
74c3cbe3 | 42 | __cacheline_aligned_in_smp DEFINE_SEQLOCK(rename_lock); |
1da177e4 LT |
43 | |
44 | EXPORT_SYMBOL(dcache_lock); | |
45 | ||
e18b890b | 46 | static struct kmem_cache *dentry_cache __read_mostly; |
1da177e4 LT |
47 | |
48 | #define DNAME_INLINE_LEN (sizeof(struct dentry)-offsetof(struct dentry,d_iname)) | |
49 | ||
50 | /* | |
51 | * This is the single most critical data structure when it comes | |
52 | * to the dcache: the hashtable for lookups. Somebody should try | |
53 | * to make this good - I've just made it work. | |
54 | * | |
55 | * This hash-function tries to avoid losing too many bits of hash | |
56 | * information, yet avoid using a prime hash-size or similar. | |
57 | */ | |
58 | #define D_HASHBITS d_hash_shift | |
59 | #define D_HASHMASK d_hash_mask | |
60 | ||
fa3536cc ED |
61 | static unsigned int d_hash_mask __read_mostly; |
62 | static unsigned int d_hash_shift __read_mostly; | |
63 | static struct hlist_head *dentry_hashtable __read_mostly; | |
1da177e4 LT |
64 | static LIST_HEAD(dentry_unused); |
65 | ||
66 | /* Statistics gathering. */ | |
67 | struct dentry_stat_t dentry_stat = { | |
68 | .age_limit = 45, | |
69 | }; | |
70 | ||
b3423415 | 71 | static void __d_free(struct dentry *dentry) |
1da177e4 | 72 | { |
1da177e4 LT |
73 | if (dname_external(dentry)) |
74 | kfree(dentry->d_name.name); | |
75 | kmem_cache_free(dentry_cache, dentry); | |
76 | } | |
77 | ||
b3423415 ED |
78 | static void d_callback(struct rcu_head *head) |
79 | { | |
80 | struct dentry * dentry = container_of(head, struct dentry, d_u.d_rcu); | |
81 | __d_free(dentry); | |
82 | } | |
83 | ||
1da177e4 LT |
84 | /* |
85 | * no dcache_lock, please. The caller must decrement dentry_stat.nr_dentry | |
86 | * inside dcache_lock. | |
87 | */ | |
88 | static void d_free(struct dentry *dentry) | |
89 | { | |
90 | if (dentry->d_op && dentry->d_op->d_release) | |
91 | dentry->d_op->d_release(dentry); | |
b3423415 | 92 | /* if dentry was never inserted into hash, immediate free is OK */ |
e8462caa | 93 | if (hlist_unhashed(&dentry->d_hash)) |
b3423415 ED |
94 | __d_free(dentry); |
95 | else | |
96 | call_rcu(&dentry->d_u.d_rcu, d_callback); | |
1da177e4 LT |
97 | } |
98 | ||
4a0962ab CL |
99 | static void dentry_lru_remove(struct dentry *dentry) |
100 | { | |
101 | if (!list_empty(&dentry->d_lru)) { | |
102 | list_del_init(&dentry->d_lru); | |
103 | dentry_stat.nr_unused--; | |
104 | } | |
105 | } | |
106 | ||
1da177e4 LT |
107 | /* |
108 | * Release the dentry's inode, using the filesystem | |
109 | * d_iput() operation if defined. | |
1da177e4 | 110 | */ |
858119e1 | 111 | static void dentry_iput(struct dentry * dentry) |
31f3e0b3 MS |
112 | __releases(dentry->d_lock) |
113 | __releases(dcache_lock) | |
1da177e4 LT |
114 | { |
115 | struct inode *inode = dentry->d_inode; | |
116 | if (inode) { | |
117 | dentry->d_inode = NULL; | |
118 | list_del_init(&dentry->d_alias); | |
119 | spin_unlock(&dentry->d_lock); | |
120 | spin_unlock(&dcache_lock); | |
f805fbda LT |
121 | if (!inode->i_nlink) |
122 | fsnotify_inoderemove(inode); | |
1da177e4 LT |
123 | if (dentry->d_op && dentry->d_op->d_iput) |
124 | dentry->d_op->d_iput(dentry, inode); | |
125 | else | |
126 | iput(inode); | |
127 | } else { | |
128 | spin_unlock(&dentry->d_lock); | |
129 | spin_unlock(&dcache_lock); | |
130 | } | |
131 | } | |
132 | ||
d52b9086 MS |
133 | /** |
134 | * d_kill - kill dentry and return parent | |
135 | * @dentry: dentry to kill | |
136 | * | |
31f3e0b3 | 137 | * The dentry must already be unhashed and removed from the LRU. |
d52b9086 MS |
138 | * |
139 | * If this is the root of the dentry tree, return NULL. | |
140 | */ | |
141 | static struct dentry *d_kill(struct dentry *dentry) | |
31f3e0b3 MS |
142 | __releases(dentry->d_lock) |
143 | __releases(dcache_lock) | |
d52b9086 MS |
144 | { |
145 | struct dentry *parent; | |
146 | ||
147 | list_del(&dentry->d_u.d_child); | |
148 | dentry_stat.nr_dentry--; /* For d_free, below */ | |
149 | /*drops the locks, at that point nobody can reach this dentry */ | |
150 | dentry_iput(dentry); | |
151 | parent = dentry->d_parent; | |
152 | d_free(dentry); | |
153 | return dentry == parent ? NULL : parent; | |
154 | } | |
155 | ||
1da177e4 LT |
156 | /* |
157 | * This is dput | |
158 | * | |
159 | * This is complicated by the fact that we do not want to put | |
160 | * dentries that are no longer on any hash chain on the unused | |
161 | * list: we'd much rather just get rid of them immediately. | |
162 | * | |
163 | * However, that implies that we have to traverse the dentry | |
164 | * tree upwards to the parents which might _also_ now be | |
165 | * scheduled for deletion (it may have been only waiting for | |
166 | * its last child to go away). | |
167 | * | |
168 | * This tail recursion is done by hand as we don't want to depend | |
169 | * on the compiler to always get this right (gcc generally doesn't). | |
170 | * Real recursion would eat up our stack space. | |
171 | */ | |
172 | ||
173 | /* | |
174 | * dput - release a dentry | |
175 | * @dentry: dentry to release | |
176 | * | |
177 | * Release a dentry. This will drop the usage count and if appropriate | |
178 | * call the dentry unlink method as well as removing it from the queues and | |
179 | * releasing its resources. If the parent dentries were scheduled for release | |
180 | * they too may now get deleted. | |
181 | * | |
182 | * no dcache lock, please. | |
183 | */ | |
184 | ||
185 | void dput(struct dentry *dentry) | |
186 | { | |
187 | if (!dentry) | |
188 | return; | |
189 | ||
190 | repeat: | |
191 | if (atomic_read(&dentry->d_count) == 1) | |
192 | might_sleep(); | |
193 | if (!atomic_dec_and_lock(&dentry->d_count, &dcache_lock)) | |
194 | return; | |
195 | ||
196 | spin_lock(&dentry->d_lock); | |
197 | if (atomic_read(&dentry->d_count)) { | |
198 | spin_unlock(&dentry->d_lock); | |
199 | spin_unlock(&dcache_lock); | |
200 | return; | |
201 | } | |
202 | ||
203 | /* | |
204 | * AV: ->d_delete() is _NOT_ allowed to block now. | |
205 | */ | |
206 | if (dentry->d_op && dentry->d_op->d_delete) { | |
207 | if (dentry->d_op->d_delete(dentry)) | |
208 | goto unhash_it; | |
209 | } | |
210 | /* Unreachable? Get rid of it */ | |
211 | if (d_unhashed(dentry)) | |
212 | goto kill_it; | |
213 | if (list_empty(&dentry->d_lru)) { | |
214 | dentry->d_flags |= DCACHE_REFERENCED; | |
215 | list_add(&dentry->d_lru, &dentry_unused); | |
216 | dentry_stat.nr_unused++; | |
217 | } | |
218 | spin_unlock(&dentry->d_lock); | |
219 | spin_unlock(&dcache_lock); | |
220 | return; | |
221 | ||
222 | unhash_it: | |
223 | __d_drop(dentry); | |
d52b9086 | 224 | kill_it: |
4a0962ab | 225 | dentry_lru_remove(dentry); |
d52b9086 MS |
226 | dentry = d_kill(dentry); |
227 | if (dentry) | |
228 | goto repeat; | |
1da177e4 LT |
229 | } |
230 | ||
231 | /** | |
232 | * d_invalidate - invalidate a dentry | |
233 | * @dentry: dentry to invalidate | |
234 | * | |
235 | * Try to invalidate the dentry if it turns out to be | |
236 | * possible. If there are other dentries that can be | |
237 | * reached through this one we can't delete it and we | |
238 | * return -EBUSY. On success we return 0. | |
239 | * | |
240 | * no dcache lock. | |
241 | */ | |
242 | ||
243 | int d_invalidate(struct dentry * dentry) | |
244 | { | |
245 | /* | |
246 | * If it's already been dropped, return OK. | |
247 | */ | |
248 | spin_lock(&dcache_lock); | |
249 | if (d_unhashed(dentry)) { | |
250 | spin_unlock(&dcache_lock); | |
251 | return 0; | |
252 | } | |
253 | /* | |
254 | * Check whether to do a partial shrink_dcache | |
255 | * to get rid of unused child entries. | |
256 | */ | |
257 | if (!list_empty(&dentry->d_subdirs)) { | |
258 | spin_unlock(&dcache_lock); | |
259 | shrink_dcache_parent(dentry); | |
260 | spin_lock(&dcache_lock); | |
261 | } | |
262 | ||
263 | /* | |
264 | * Somebody else still using it? | |
265 | * | |
266 | * If it's a directory, we can't drop it | |
267 | * for fear of somebody re-populating it | |
268 | * with children (even though dropping it | |
269 | * would make it unreachable from the root, | |
270 | * we might still populate it if it was a | |
271 | * working directory or similar). | |
272 | */ | |
273 | spin_lock(&dentry->d_lock); | |
274 | if (atomic_read(&dentry->d_count) > 1) { | |
275 | if (dentry->d_inode && S_ISDIR(dentry->d_inode->i_mode)) { | |
276 | spin_unlock(&dentry->d_lock); | |
277 | spin_unlock(&dcache_lock); | |
278 | return -EBUSY; | |
279 | } | |
280 | } | |
281 | ||
282 | __d_drop(dentry); | |
283 | spin_unlock(&dentry->d_lock); | |
284 | spin_unlock(&dcache_lock); | |
285 | return 0; | |
286 | } | |
287 | ||
288 | /* This should be called _only_ with dcache_lock held */ | |
289 | ||
290 | static inline struct dentry * __dget_locked(struct dentry *dentry) | |
291 | { | |
292 | atomic_inc(&dentry->d_count); | |
4a0962ab | 293 | dentry_lru_remove(dentry); |
1da177e4 LT |
294 | return dentry; |
295 | } | |
296 | ||
297 | struct dentry * dget_locked(struct dentry *dentry) | |
298 | { | |
299 | return __dget_locked(dentry); | |
300 | } | |
301 | ||
302 | /** | |
303 | * d_find_alias - grab a hashed alias of inode | |
304 | * @inode: inode in question | |
305 | * @want_discon: flag, used by d_splice_alias, to request | |
306 | * that only a DISCONNECTED alias be returned. | |
307 | * | |
308 | * If inode has a hashed alias, or is a directory and has any alias, | |
309 | * acquire the reference to alias and return it. Otherwise return NULL. | |
310 | * Notice that if inode is a directory there can be only one alias and | |
311 | * it can be unhashed only if it has no children, or if it is the root | |
312 | * of a filesystem. | |
313 | * | |
21c0d8fd | 314 | * If the inode has an IS_ROOT, DCACHE_DISCONNECTED alias, then prefer |
1da177e4 | 315 | * any other hashed alias over that one unless @want_discon is set, |
21c0d8fd | 316 | * in which case only return an IS_ROOT, DCACHE_DISCONNECTED alias. |
1da177e4 LT |
317 | */ |
318 | ||
319 | static struct dentry * __d_find_alias(struct inode *inode, int want_discon) | |
320 | { | |
321 | struct list_head *head, *next, *tmp; | |
322 | struct dentry *alias, *discon_alias=NULL; | |
323 | ||
324 | head = &inode->i_dentry; | |
325 | next = inode->i_dentry.next; | |
326 | while (next != head) { | |
327 | tmp = next; | |
328 | next = tmp->next; | |
329 | prefetch(next); | |
330 | alias = list_entry(tmp, struct dentry, d_alias); | |
331 | if (S_ISDIR(inode->i_mode) || !d_unhashed(alias)) { | |
21c0d8fd N |
332 | if (IS_ROOT(alias) && |
333 | (alias->d_flags & DCACHE_DISCONNECTED)) | |
1da177e4 LT |
334 | discon_alias = alias; |
335 | else if (!want_discon) { | |
336 | __dget_locked(alias); | |
337 | return alias; | |
338 | } | |
339 | } | |
340 | } | |
341 | if (discon_alias) | |
342 | __dget_locked(discon_alias); | |
343 | return discon_alias; | |
344 | } | |
345 | ||
346 | struct dentry * d_find_alias(struct inode *inode) | |
347 | { | |
214fda1f DH |
348 | struct dentry *de = NULL; |
349 | ||
350 | if (!list_empty(&inode->i_dentry)) { | |
351 | spin_lock(&dcache_lock); | |
352 | de = __d_find_alias(inode, 0); | |
353 | spin_unlock(&dcache_lock); | |
354 | } | |
1da177e4 LT |
355 | return de; |
356 | } | |
357 | ||
358 | /* | |
359 | * Try to kill dentries associated with this inode. | |
360 | * WARNING: you must own a reference to inode. | |
361 | */ | |
362 | void d_prune_aliases(struct inode *inode) | |
363 | { | |
0cdca3f9 | 364 | struct dentry *dentry; |
1da177e4 LT |
365 | restart: |
366 | spin_lock(&dcache_lock); | |
0cdca3f9 | 367 | list_for_each_entry(dentry, &inode->i_dentry, d_alias) { |
1da177e4 LT |
368 | spin_lock(&dentry->d_lock); |
369 | if (!atomic_read(&dentry->d_count)) { | |
370 | __dget_locked(dentry); | |
371 | __d_drop(dentry); | |
372 | spin_unlock(&dentry->d_lock); | |
373 | spin_unlock(&dcache_lock); | |
374 | dput(dentry); | |
375 | goto restart; | |
376 | } | |
377 | spin_unlock(&dentry->d_lock); | |
378 | } | |
379 | spin_unlock(&dcache_lock); | |
380 | } | |
381 | ||
382 | /* | |
d702ccb3 AM |
383 | * Throw away a dentry - free the inode, dput the parent. This requires that |
384 | * the LRU list has already been removed. | |
385 | * | |
85864e10 MS |
386 | * Try to prune ancestors as well. This is necessary to prevent |
387 | * quadratic behavior of shrink_dcache_parent(), but is also expected | |
388 | * to be beneficial in reducing dentry cache fragmentation. | |
1da177e4 | 389 | */ |
85864e10 | 390 | static void prune_one_dentry(struct dentry * dentry) |
31f3e0b3 MS |
391 | __releases(dentry->d_lock) |
392 | __releases(dcache_lock) | |
393 | __acquires(dcache_lock) | |
1da177e4 | 394 | { |
1da177e4 | 395 | __d_drop(dentry); |
d52b9086 | 396 | dentry = d_kill(dentry); |
d52b9086 MS |
397 | |
398 | /* | |
399 | * Prune ancestors. Locking is simpler than in dput(), | |
400 | * because dcache_lock needs to be taken anyway. | |
401 | */ | |
1da177e4 | 402 | spin_lock(&dcache_lock); |
d52b9086 MS |
403 | while (dentry) { |
404 | if (!atomic_dec_and_lock(&dentry->d_count, &dentry->d_lock)) | |
405 | return; | |
406 | ||
407 | if (dentry->d_op && dentry->d_op->d_delete) | |
408 | dentry->d_op->d_delete(dentry); | |
4a0962ab | 409 | dentry_lru_remove(dentry); |
d52b9086 MS |
410 | __d_drop(dentry); |
411 | dentry = d_kill(dentry); | |
412 | spin_lock(&dcache_lock); | |
413 | } | |
1da177e4 LT |
414 | } |
415 | ||
416 | /** | |
417 | * prune_dcache - shrink the dcache | |
418 | * @count: number of entries to try and free | |
0feae5c4 N |
419 | * @sb: if given, ignore dentries for other superblocks |
420 | * which are being unmounted. | |
1da177e4 LT |
421 | * |
422 | * Shrink the dcache. This is done when we need | |
423 | * more memory, or simply when we need to unmount | |
424 | * something (at which point we need to unuse | |
425 | * all dentries). | |
426 | * | |
427 | * This function may fail to free any resources if | |
428 | * all the dentries are in use. | |
429 | */ | |
430 | ||
85864e10 | 431 | static void prune_dcache(int count, struct super_block *sb) |
1da177e4 LT |
432 | { |
433 | spin_lock(&dcache_lock); | |
434 | for (; count ; count--) { | |
435 | struct dentry *dentry; | |
436 | struct list_head *tmp; | |
0feae5c4 | 437 | struct rw_semaphore *s_umount; |
1da177e4 LT |
438 | |
439 | cond_resched_lock(&dcache_lock); | |
440 | ||
441 | tmp = dentry_unused.prev; | |
f58a1ebb | 442 | if (sb) { |
0feae5c4 N |
443 | /* Try to find a dentry for this sb, but don't try |
444 | * too hard, if they aren't near the tail they will | |
445 | * be moved down again soon | |
446 | */ | |
447 | int skip = count; | |
448 | while (skip && tmp != &dentry_unused && | |
449 | list_entry(tmp, struct dentry, d_lru)->d_sb != sb) { | |
450 | skip--; | |
451 | tmp = tmp->prev; | |
452 | } | |
453 | } | |
1da177e4 LT |
454 | if (tmp == &dentry_unused) |
455 | break; | |
456 | list_del_init(tmp); | |
457 | prefetch(dentry_unused.prev); | |
458 | dentry_stat.nr_unused--; | |
459 | dentry = list_entry(tmp, struct dentry, d_lru); | |
460 | ||
461 | spin_lock(&dentry->d_lock); | |
462 | /* | |
463 | * We found an inuse dentry which was not removed from | |
464 | * dentry_unused because of laziness during lookup. Do not free | |
465 | * it - just keep it off the dentry_unused list. | |
466 | */ | |
467 | if (atomic_read(&dentry->d_count)) { | |
468 | spin_unlock(&dentry->d_lock); | |
469 | continue; | |
470 | } | |
471 | /* If the dentry was recently referenced, don't free it. */ | |
472 | if (dentry->d_flags & DCACHE_REFERENCED) { | |
473 | dentry->d_flags &= ~DCACHE_REFERENCED; | |
474 | list_add(&dentry->d_lru, &dentry_unused); | |
475 | dentry_stat.nr_unused++; | |
476 | spin_unlock(&dentry->d_lock); | |
477 | continue; | |
478 | } | |
0feae5c4 N |
479 | /* |
480 | * If the dentry is not DCACHED_REFERENCED, it is time | |
481 | * to remove it from the dcache, provided the super block is | |
482 | * NULL (which means we are trying to reclaim memory) | |
483 | * or this dentry belongs to the same super block that | |
484 | * we want to shrink. | |
485 | */ | |
486 | /* | |
487 | * If this dentry is for "my" filesystem, then I can prune it | |
488 | * without taking the s_umount lock (I already hold it). | |
489 | */ | |
490 | if (sb && dentry->d_sb == sb) { | |
85864e10 | 491 | prune_one_dentry(dentry); |
0feae5c4 N |
492 | continue; |
493 | } | |
494 | /* | |
495 | * ...otherwise we need to be sure this filesystem isn't being | |
496 | * unmounted, otherwise we could race with | |
497 | * generic_shutdown_super(), and end up holding a reference to | |
498 | * an inode while the filesystem is unmounted. | |
499 | * So we try to get s_umount, and make sure s_root isn't NULL. | |
500 | * (Take a local copy of s_umount to avoid a use-after-free of | |
501 | * `dentry'). | |
502 | */ | |
503 | s_umount = &dentry->d_sb->s_umount; | |
504 | if (down_read_trylock(s_umount)) { | |
505 | if (dentry->d_sb->s_root != NULL) { | |
85864e10 | 506 | prune_one_dentry(dentry); |
0feae5c4 N |
507 | up_read(s_umount); |
508 | continue; | |
509 | } | |
510 | up_read(s_umount); | |
511 | } | |
512 | spin_unlock(&dentry->d_lock); | |
6eac3f93 VA |
513 | /* |
514 | * Insert dentry at the head of the list as inserting at the | |
515 | * tail leads to a cycle. | |
0feae5c4 | 516 | */ |
6eac3f93 VA |
517 | list_add(&dentry->d_lru, &dentry_unused); |
518 | dentry_stat.nr_unused++; | |
1da177e4 LT |
519 | } |
520 | spin_unlock(&dcache_lock); | |
521 | } | |
522 | ||
523 | /* | |
524 | * Shrink the dcache for the specified super block. | |
525 | * This allows us to unmount a device without disturbing | |
526 | * the dcache for the other devices. | |
527 | * | |
528 | * This implementation makes just two traversals of the | |
529 | * unused list. On the first pass we move the selected | |
530 | * dentries to the most recent end, and on the second | |
531 | * pass we free them. The second pass must restart after | |
532 | * each dput(), but since the target dentries are all at | |
533 | * the end, it's really just a single traversal. | |
534 | */ | |
535 | ||
536 | /** | |
537 | * shrink_dcache_sb - shrink dcache for a superblock | |
538 | * @sb: superblock | |
539 | * | |
540 | * Shrink the dcache for the specified super block. This | |
541 | * is used to free the dcache before unmounting a file | |
542 | * system | |
543 | */ | |
544 | ||
545 | void shrink_dcache_sb(struct super_block * sb) | |
546 | { | |
547 | struct list_head *tmp, *next; | |
548 | struct dentry *dentry; | |
549 | ||
550 | /* | |
551 | * Pass one ... move the dentries for the specified | |
552 | * superblock to the most recent end of the unused list. | |
553 | */ | |
554 | spin_lock(&dcache_lock); | |
37c42524 | 555 | list_for_each_prev_safe(tmp, next, &dentry_unused) { |
1da177e4 LT |
556 | dentry = list_entry(tmp, struct dentry, d_lru); |
557 | if (dentry->d_sb != sb) | |
558 | continue; | |
37c42524 | 559 | list_move_tail(tmp, &dentry_unused); |
1da177e4 LT |
560 | } |
561 | ||
562 | /* | |
563 | * Pass two ... free the dentries for this superblock. | |
564 | */ | |
565 | repeat: | |
37c42524 | 566 | list_for_each_prev_safe(tmp, next, &dentry_unused) { |
1da177e4 LT |
567 | dentry = list_entry(tmp, struct dentry, d_lru); |
568 | if (dentry->d_sb != sb) | |
569 | continue; | |
570 | dentry_stat.nr_unused--; | |
571 | list_del_init(tmp); | |
572 | spin_lock(&dentry->d_lock); | |
573 | if (atomic_read(&dentry->d_count)) { | |
574 | spin_unlock(&dentry->d_lock); | |
575 | continue; | |
576 | } | |
85864e10 | 577 | prune_one_dentry(dentry); |
2ab13460 | 578 | cond_resched_lock(&dcache_lock); |
1da177e4 LT |
579 | goto repeat; |
580 | } | |
581 | spin_unlock(&dcache_lock); | |
582 | } | |
583 | ||
c636ebdb DH |
584 | /* |
585 | * destroy a single subtree of dentries for unmount | |
586 | * - see the comments on shrink_dcache_for_umount() for a description of the | |
587 | * locking | |
588 | */ | |
589 | static void shrink_dcache_for_umount_subtree(struct dentry *dentry) | |
590 | { | |
591 | struct dentry *parent; | |
f8713576 | 592 | unsigned detached = 0; |
c636ebdb DH |
593 | |
594 | BUG_ON(!IS_ROOT(dentry)); | |
595 | ||
596 | /* detach this root from the system */ | |
597 | spin_lock(&dcache_lock); | |
4a0962ab | 598 | dentry_lru_remove(dentry); |
c636ebdb DH |
599 | __d_drop(dentry); |
600 | spin_unlock(&dcache_lock); | |
601 | ||
602 | for (;;) { | |
603 | /* descend to the first leaf in the current subtree */ | |
604 | while (!list_empty(&dentry->d_subdirs)) { | |
605 | struct dentry *loop; | |
606 | ||
607 | /* this is a branch with children - detach all of them | |
608 | * from the system in one go */ | |
609 | spin_lock(&dcache_lock); | |
610 | list_for_each_entry(loop, &dentry->d_subdirs, | |
611 | d_u.d_child) { | |
4a0962ab | 612 | dentry_lru_remove(loop); |
c636ebdb DH |
613 | __d_drop(loop); |
614 | cond_resched_lock(&dcache_lock); | |
615 | } | |
616 | spin_unlock(&dcache_lock); | |
617 | ||
618 | /* move to the first child */ | |
619 | dentry = list_entry(dentry->d_subdirs.next, | |
620 | struct dentry, d_u.d_child); | |
621 | } | |
622 | ||
623 | /* consume the dentries from this leaf up through its parents | |
624 | * until we find one with children or run out altogether */ | |
625 | do { | |
626 | struct inode *inode; | |
627 | ||
628 | if (atomic_read(&dentry->d_count) != 0) { | |
629 | printk(KERN_ERR | |
630 | "BUG: Dentry %p{i=%lx,n=%s}" | |
631 | " still in use (%d)" | |
632 | " [unmount of %s %s]\n", | |
633 | dentry, | |
634 | dentry->d_inode ? | |
635 | dentry->d_inode->i_ino : 0UL, | |
636 | dentry->d_name.name, | |
637 | atomic_read(&dentry->d_count), | |
638 | dentry->d_sb->s_type->name, | |
639 | dentry->d_sb->s_id); | |
640 | BUG(); | |
641 | } | |
642 | ||
643 | parent = dentry->d_parent; | |
644 | if (parent == dentry) | |
645 | parent = NULL; | |
646 | else | |
647 | atomic_dec(&parent->d_count); | |
648 | ||
649 | list_del(&dentry->d_u.d_child); | |
f8713576 | 650 | detached++; |
c636ebdb DH |
651 | |
652 | inode = dentry->d_inode; | |
653 | if (inode) { | |
654 | dentry->d_inode = NULL; | |
655 | list_del_init(&dentry->d_alias); | |
656 | if (dentry->d_op && dentry->d_op->d_iput) | |
657 | dentry->d_op->d_iput(dentry, inode); | |
658 | else | |
659 | iput(inode); | |
660 | } | |
661 | ||
662 | d_free(dentry); | |
663 | ||
664 | /* finished when we fall off the top of the tree, | |
665 | * otherwise we ascend to the parent and move to the | |
666 | * next sibling if there is one */ | |
667 | if (!parent) | |
f8713576 | 668 | goto out; |
c636ebdb DH |
669 | |
670 | dentry = parent; | |
671 | ||
672 | } while (list_empty(&dentry->d_subdirs)); | |
673 | ||
674 | dentry = list_entry(dentry->d_subdirs.next, | |
675 | struct dentry, d_u.d_child); | |
676 | } | |
f8713576 DH |
677 | out: |
678 | /* several dentries were freed, need to correct nr_dentry */ | |
679 | spin_lock(&dcache_lock); | |
680 | dentry_stat.nr_dentry -= detached; | |
681 | spin_unlock(&dcache_lock); | |
c636ebdb DH |
682 | } |
683 | ||
684 | /* | |
685 | * destroy the dentries attached to a superblock on unmounting | |
686 | * - we don't need to use dentry->d_lock, and only need dcache_lock when | |
687 | * removing the dentry from the system lists and hashes because: | |
688 | * - the superblock is detached from all mountings and open files, so the | |
689 | * dentry trees will not be rearranged by the VFS | |
690 | * - s_umount is write-locked, so the memory pressure shrinker will ignore | |
691 | * any dentries belonging to this superblock that it comes across | |
692 | * - the filesystem itself is no longer permitted to rearrange the dentries | |
693 | * in this superblock | |
694 | */ | |
695 | void shrink_dcache_for_umount(struct super_block *sb) | |
696 | { | |
697 | struct dentry *dentry; | |
698 | ||
699 | if (down_read_trylock(&sb->s_umount)) | |
700 | BUG(); | |
701 | ||
702 | dentry = sb->s_root; | |
703 | sb->s_root = NULL; | |
704 | atomic_dec(&dentry->d_count); | |
705 | shrink_dcache_for_umount_subtree(dentry); | |
706 | ||
707 | while (!hlist_empty(&sb->s_anon)) { | |
708 | dentry = hlist_entry(sb->s_anon.first, struct dentry, d_hash); | |
709 | shrink_dcache_for_umount_subtree(dentry); | |
710 | } | |
711 | } | |
712 | ||
1da177e4 LT |
713 | /* |
714 | * Search for at least 1 mount point in the dentry's subdirs. | |
715 | * We descend to the next level whenever the d_subdirs | |
716 | * list is non-empty and continue searching. | |
717 | */ | |
718 | ||
719 | /** | |
720 | * have_submounts - check for mounts over a dentry | |
721 | * @parent: dentry to check. | |
722 | * | |
723 | * Return true if the parent or its subdirectories contain | |
724 | * a mount point | |
725 | */ | |
726 | ||
727 | int have_submounts(struct dentry *parent) | |
728 | { | |
729 | struct dentry *this_parent = parent; | |
730 | struct list_head *next; | |
731 | ||
732 | spin_lock(&dcache_lock); | |
733 | if (d_mountpoint(parent)) | |
734 | goto positive; | |
735 | repeat: | |
736 | next = this_parent->d_subdirs.next; | |
737 | resume: | |
738 | while (next != &this_parent->d_subdirs) { | |
739 | struct list_head *tmp = next; | |
5160ee6f | 740 | struct dentry *dentry = list_entry(tmp, struct dentry, d_u.d_child); |
1da177e4 LT |
741 | next = tmp->next; |
742 | /* Have we found a mount point ? */ | |
743 | if (d_mountpoint(dentry)) | |
744 | goto positive; | |
745 | if (!list_empty(&dentry->d_subdirs)) { | |
746 | this_parent = dentry; | |
747 | goto repeat; | |
748 | } | |
749 | } | |
750 | /* | |
751 | * All done at this level ... ascend and resume the search. | |
752 | */ | |
753 | if (this_parent != parent) { | |
5160ee6f | 754 | next = this_parent->d_u.d_child.next; |
1da177e4 LT |
755 | this_parent = this_parent->d_parent; |
756 | goto resume; | |
757 | } | |
758 | spin_unlock(&dcache_lock); | |
759 | return 0; /* No mount points found in tree */ | |
760 | positive: | |
761 | spin_unlock(&dcache_lock); | |
762 | return 1; | |
763 | } | |
764 | ||
765 | /* | |
766 | * Search the dentry child list for the specified parent, | |
767 | * and move any unused dentries to the end of the unused | |
768 | * list for prune_dcache(). We descend to the next level | |
769 | * whenever the d_subdirs list is non-empty and continue | |
770 | * searching. | |
771 | * | |
772 | * It returns zero iff there are no unused children, | |
773 | * otherwise it returns the number of children moved to | |
774 | * the end of the unused list. This may not be the total | |
775 | * number of unused children, because select_parent can | |
776 | * drop the lock and return early due to latency | |
777 | * constraints. | |
778 | */ | |
779 | static int select_parent(struct dentry * parent) | |
780 | { | |
781 | struct dentry *this_parent = parent; | |
782 | struct list_head *next; | |
783 | int found = 0; | |
784 | ||
785 | spin_lock(&dcache_lock); | |
786 | repeat: | |
787 | next = this_parent->d_subdirs.next; | |
788 | resume: | |
789 | while (next != &this_parent->d_subdirs) { | |
790 | struct list_head *tmp = next; | |
5160ee6f | 791 | struct dentry *dentry = list_entry(tmp, struct dentry, d_u.d_child); |
1da177e4 LT |
792 | next = tmp->next; |
793 | ||
4a0962ab | 794 | dentry_lru_remove(dentry); |
1da177e4 LT |
795 | /* |
796 | * move only zero ref count dentries to the end | |
797 | * of the unused list for prune_dcache | |
798 | */ | |
799 | if (!atomic_read(&dentry->d_count)) { | |
8e13059a | 800 | list_add_tail(&dentry->d_lru, &dentry_unused); |
1da177e4 LT |
801 | dentry_stat.nr_unused++; |
802 | found++; | |
803 | } | |
804 | ||
805 | /* | |
806 | * We can return to the caller if we have found some (this | |
807 | * ensures forward progress). We'll be coming back to find | |
808 | * the rest. | |
809 | */ | |
810 | if (found && need_resched()) | |
811 | goto out; | |
812 | ||
813 | /* | |
814 | * Descend a level if the d_subdirs list is non-empty. | |
815 | */ | |
816 | if (!list_empty(&dentry->d_subdirs)) { | |
817 | this_parent = dentry; | |
1da177e4 LT |
818 | goto repeat; |
819 | } | |
820 | } | |
821 | /* | |
822 | * All done at this level ... ascend and resume the search. | |
823 | */ | |
824 | if (this_parent != parent) { | |
5160ee6f | 825 | next = this_parent->d_u.d_child.next; |
1da177e4 | 826 | this_parent = this_parent->d_parent; |
1da177e4 LT |
827 | goto resume; |
828 | } | |
829 | out: | |
830 | spin_unlock(&dcache_lock); | |
831 | return found; | |
832 | } | |
833 | ||
834 | /** | |
835 | * shrink_dcache_parent - prune dcache | |
836 | * @parent: parent of entries to prune | |
837 | * | |
838 | * Prune the dcache to remove unused children of the parent dentry. | |
839 | */ | |
840 | ||
841 | void shrink_dcache_parent(struct dentry * parent) | |
842 | { | |
843 | int found; | |
844 | ||
845 | while ((found = select_parent(parent)) != 0) | |
85864e10 | 846 | prune_dcache(found, parent->d_sb); |
1da177e4 LT |
847 | } |
848 | ||
1da177e4 LT |
849 | /* |
850 | * Scan `nr' dentries and return the number which remain. | |
851 | * | |
852 | * We need to avoid reentering the filesystem if the caller is performing a | |
853 | * GFP_NOFS allocation attempt. One example deadlock is: | |
854 | * | |
855 | * ext2_new_block->getblk->GFP->shrink_dcache_memory->prune_dcache-> | |
856 | * prune_one_dentry->dput->dentry_iput->iput->inode->i_sb->s_op->put_inode-> | |
857 | * ext2_discard_prealloc->ext2_free_blocks->lock_super->DEADLOCK. | |
858 | * | |
859 | * In this case we return -1 to tell the caller that we baled. | |
860 | */ | |
27496a8c | 861 | static int shrink_dcache_memory(int nr, gfp_t gfp_mask) |
1da177e4 LT |
862 | { |
863 | if (nr) { | |
864 | if (!(gfp_mask & __GFP_FS)) | |
865 | return -1; | |
85864e10 | 866 | prune_dcache(nr, NULL); |
1da177e4 LT |
867 | } |
868 | return (dentry_stat.nr_unused / 100) * sysctl_vfs_cache_pressure; | |
869 | } | |
870 | ||
8e1f936b RR |
871 | static struct shrinker dcache_shrinker = { |
872 | .shrink = shrink_dcache_memory, | |
873 | .seeks = DEFAULT_SEEKS, | |
874 | }; | |
875 | ||
1da177e4 LT |
876 | /** |
877 | * d_alloc - allocate a dcache entry | |
878 | * @parent: parent of entry to allocate | |
879 | * @name: qstr of the name | |
880 | * | |
881 | * Allocates a dentry. It returns %NULL if there is insufficient memory | |
882 | * available. On a success the dentry is returned. The name passed in is | |
883 | * copied and the copy passed in may be reused after this call. | |
884 | */ | |
885 | ||
886 | struct dentry *d_alloc(struct dentry * parent, const struct qstr *name) | |
887 | { | |
888 | struct dentry *dentry; | |
889 | char *dname; | |
890 | ||
e12ba74d | 891 | dentry = kmem_cache_alloc(dentry_cache, GFP_KERNEL); |
1da177e4 LT |
892 | if (!dentry) |
893 | return NULL; | |
894 | ||
895 | if (name->len > DNAME_INLINE_LEN-1) { | |
896 | dname = kmalloc(name->len + 1, GFP_KERNEL); | |
897 | if (!dname) { | |
898 | kmem_cache_free(dentry_cache, dentry); | |
899 | return NULL; | |
900 | } | |
901 | } else { | |
902 | dname = dentry->d_iname; | |
903 | } | |
904 | dentry->d_name.name = dname; | |
905 | ||
906 | dentry->d_name.len = name->len; | |
907 | dentry->d_name.hash = name->hash; | |
908 | memcpy(dname, name->name, name->len); | |
909 | dname[name->len] = 0; | |
910 | ||
911 | atomic_set(&dentry->d_count, 1); | |
912 | dentry->d_flags = DCACHE_UNHASHED; | |
913 | spin_lock_init(&dentry->d_lock); | |
914 | dentry->d_inode = NULL; | |
915 | dentry->d_parent = NULL; | |
916 | dentry->d_sb = NULL; | |
917 | dentry->d_op = NULL; | |
918 | dentry->d_fsdata = NULL; | |
919 | dentry->d_mounted = 0; | |
47ba87e0 | 920 | #ifdef CONFIG_PROFILING |
1da177e4 | 921 | dentry->d_cookie = NULL; |
47ba87e0 | 922 | #endif |
1da177e4 LT |
923 | INIT_HLIST_NODE(&dentry->d_hash); |
924 | INIT_LIST_HEAD(&dentry->d_lru); | |
925 | INIT_LIST_HEAD(&dentry->d_subdirs); | |
926 | INIT_LIST_HEAD(&dentry->d_alias); | |
927 | ||
928 | if (parent) { | |
929 | dentry->d_parent = dget(parent); | |
930 | dentry->d_sb = parent->d_sb; | |
931 | } else { | |
5160ee6f | 932 | INIT_LIST_HEAD(&dentry->d_u.d_child); |
1da177e4 LT |
933 | } |
934 | ||
935 | spin_lock(&dcache_lock); | |
936 | if (parent) | |
5160ee6f | 937 | list_add(&dentry->d_u.d_child, &parent->d_subdirs); |
1da177e4 LT |
938 | dentry_stat.nr_dentry++; |
939 | spin_unlock(&dcache_lock); | |
940 | ||
941 | return dentry; | |
942 | } | |
943 | ||
944 | struct dentry *d_alloc_name(struct dentry *parent, const char *name) | |
945 | { | |
946 | struct qstr q; | |
947 | ||
948 | q.name = name; | |
949 | q.len = strlen(name); | |
950 | q.hash = full_name_hash(q.name, q.len); | |
951 | return d_alloc(parent, &q); | |
952 | } | |
953 | ||
954 | /** | |
955 | * d_instantiate - fill in inode information for a dentry | |
956 | * @entry: dentry to complete | |
957 | * @inode: inode to attach to this dentry | |
958 | * | |
959 | * Fill in inode information in the entry. | |
960 | * | |
961 | * This turns negative dentries into productive full members | |
962 | * of society. | |
963 | * | |
964 | * NOTE! This assumes that the inode count has been incremented | |
965 | * (or otherwise set) by the caller to indicate that it is now | |
966 | * in use by the dcache. | |
967 | */ | |
968 | ||
969 | void d_instantiate(struct dentry *entry, struct inode * inode) | |
970 | { | |
28133c7b | 971 | BUG_ON(!list_empty(&entry->d_alias)); |
1da177e4 LT |
972 | spin_lock(&dcache_lock); |
973 | if (inode) | |
974 | list_add(&entry->d_alias, &inode->i_dentry); | |
975 | entry->d_inode = inode; | |
c32ccd87 | 976 | fsnotify_d_instantiate(entry, inode); |
1da177e4 LT |
977 | spin_unlock(&dcache_lock); |
978 | security_d_instantiate(entry, inode); | |
979 | } | |
980 | ||
981 | /** | |
982 | * d_instantiate_unique - instantiate a non-aliased dentry | |
983 | * @entry: dentry to instantiate | |
984 | * @inode: inode to attach to this dentry | |
985 | * | |
986 | * Fill in inode information in the entry. On success, it returns NULL. | |
987 | * If an unhashed alias of "entry" already exists, then we return the | |
e866cfa9 | 988 | * aliased dentry instead and drop one reference to inode. |
1da177e4 LT |
989 | * |
990 | * Note that in order to avoid conflicts with rename() etc, the caller | |
991 | * had better be holding the parent directory semaphore. | |
e866cfa9 OD |
992 | * |
993 | * This also assumes that the inode count has been incremented | |
994 | * (or otherwise set) by the caller to indicate that it is now | |
995 | * in use by the dcache. | |
1da177e4 | 996 | */ |
770bfad8 DH |
997 | static struct dentry *__d_instantiate_unique(struct dentry *entry, |
998 | struct inode *inode) | |
1da177e4 LT |
999 | { |
1000 | struct dentry *alias; | |
1001 | int len = entry->d_name.len; | |
1002 | const char *name = entry->d_name.name; | |
1003 | unsigned int hash = entry->d_name.hash; | |
1004 | ||
770bfad8 DH |
1005 | if (!inode) { |
1006 | entry->d_inode = NULL; | |
1007 | return NULL; | |
1008 | } | |
1009 | ||
1da177e4 LT |
1010 | list_for_each_entry(alias, &inode->i_dentry, d_alias) { |
1011 | struct qstr *qstr = &alias->d_name; | |
1012 | ||
1013 | if (qstr->hash != hash) | |
1014 | continue; | |
1015 | if (alias->d_parent != entry->d_parent) | |
1016 | continue; | |
1017 | if (qstr->len != len) | |
1018 | continue; | |
1019 | if (memcmp(qstr->name, name, len)) | |
1020 | continue; | |
1021 | dget_locked(alias); | |
1da177e4 LT |
1022 | return alias; |
1023 | } | |
770bfad8 | 1024 | |
1da177e4 | 1025 | list_add(&entry->d_alias, &inode->i_dentry); |
1da177e4 | 1026 | entry->d_inode = inode; |
c32ccd87 | 1027 | fsnotify_d_instantiate(entry, inode); |
1da177e4 LT |
1028 | return NULL; |
1029 | } | |
770bfad8 DH |
1030 | |
1031 | struct dentry *d_instantiate_unique(struct dentry *entry, struct inode *inode) | |
1032 | { | |
1033 | struct dentry *result; | |
1034 | ||
1035 | BUG_ON(!list_empty(&entry->d_alias)); | |
1036 | ||
1037 | spin_lock(&dcache_lock); | |
1038 | result = __d_instantiate_unique(entry, inode); | |
1039 | spin_unlock(&dcache_lock); | |
1040 | ||
1041 | if (!result) { | |
1042 | security_d_instantiate(entry, inode); | |
1043 | return NULL; | |
1044 | } | |
1045 | ||
1046 | BUG_ON(!d_unhashed(result)); | |
1047 | iput(inode); | |
1048 | return result; | |
1049 | } | |
1050 | ||
1da177e4 LT |
1051 | EXPORT_SYMBOL(d_instantiate_unique); |
1052 | ||
1053 | /** | |
1054 | * d_alloc_root - allocate root dentry | |
1055 | * @root_inode: inode to allocate the root for | |
1056 | * | |
1057 | * Allocate a root ("/") dentry for the inode given. The inode is | |
1058 | * instantiated and returned. %NULL is returned if there is insufficient | |
1059 | * memory or the inode passed is %NULL. | |
1060 | */ | |
1061 | ||
1062 | struct dentry * d_alloc_root(struct inode * root_inode) | |
1063 | { | |
1064 | struct dentry *res = NULL; | |
1065 | ||
1066 | if (root_inode) { | |
1067 | static const struct qstr name = { .name = "/", .len = 1 }; | |
1068 | ||
1069 | res = d_alloc(NULL, &name); | |
1070 | if (res) { | |
1071 | res->d_sb = root_inode->i_sb; | |
1072 | res->d_parent = res; | |
1073 | d_instantiate(res, root_inode); | |
1074 | } | |
1075 | } | |
1076 | return res; | |
1077 | } | |
1078 | ||
1079 | static inline struct hlist_head *d_hash(struct dentry *parent, | |
1080 | unsigned long hash) | |
1081 | { | |
1082 | hash += ((unsigned long) parent ^ GOLDEN_RATIO_PRIME) / L1_CACHE_BYTES; | |
1083 | hash = hash ^ ((hash ^ GOLDEN_RATIO_PRIME) >> D_HASHBITS); | |
1084 | return dentry_hashtable + (hash & D_HASHMASK); | |
1085 | } | |
1086 | ||
1087 | /** | |
1088 | * d_alloc_anon - allocate an anonymous dentry | |
1089 | * @inode: inode to allocate the dentry for | |
1090 | * | |
1091 | * This is similar to d_alloc_root. It is used by filesystems when | |
1092 | * creating a dentry for a given inode, often in the process of | |
1093 | * mapping a filehandle to a dentry. The returned dentry may be | |
1094 | * anonymous, or may have a full name (if the inode was already | |
1095 | * in the cache). The file system may need to make further | |
1096 | * efforts to connect this dentry into the dcache properly. | |
1097 | * | |
1098 | * When called on a directory inode, we must ensure that | |
1099 | * the inode only ever has one dentry. If a dentry is | |
1100 | * found, that is returned instead of allocating a new one. | |
1101 | * | |
1102 | * On successful return, the reference to the inode has been transferred | |
1103 | * to the dentry. If %NULL is returned (indicating kmalloc failure), | |
1104 | * the reference on the inode has not been released. | |
1105 | */ | |
1106 | ||
1107 | struct dentry * d_alloc_anon(struct inode *inode) | |
1108 | { | |
1109 | static const struct qstr anonstring = { .name = "" }; | |
1110 | struct dentry *tmp; | |
1111 | struct dentry *res; | |
1112 | ||
1113 | if ((res = d_find_alias(inode))) { | |
1114 | iput(inode); | |
1115 | return res; | |
1116 | } | |
1117 | ||
1118 | tmp = d_alloc(NULL, &anonstring); | |
1119 | if (!tmp) | |
1120 | return NULL; | |
1121 | ||
1122 | tmp->d_parent = tmp; /* make sure dput doesn't croak */ | |
1123 | ||
1124 | spin_lock(&dcache_lock); | |
1125 | res = __d_find_alias(inode, 0); | |
1126 | if (!res) { | |
1127 | /* attach a disconnected dentry */ | |
1128 | res = tmp; | |
1129 | tmp = NULL; | |
1130 | spin_lock(&res->d_lock); | |
1131 | res->d_sb = inode->i_sb; | |
1132 | res->d_parent = res; | |
1133 | res->d_inode = inode; | |
1134 | res->d_flags |= DCACHE_DISCONNECTED; | |
1135 | res->d_flags &= ~DCACHE_UNHASHED; | |
1136 | list_add(&res->d_alias, &inode->i_dentry); | |
1137 | hlist_add_head(&res->d_hash, &inode->i_sb->s_anon); | |
1138 | spin_unlock(&res->d_lock); | |
1139 | ||
1140 | inode = NULL; /* don't drop reference */ | |
1141 | } | |
1142 | spin_unlock(&dcache_lock); | |
1143 | ||
1144 | if (inode) | |
1145 | iput(inode); | |
1146 | if (tmp) | |
1147 | dput(tmp); | |
1148 | return res; | |
1149 | } | |
1150 | ||
1151 | ||
1152 | /** | |
1153 | * d_splice_alias - splice a disconnected dentry into the tree if one exists | |
1154 | * @inode: the inode which may have a disconnected dentry | |
1155 | * @dentry: a negative dentry which we want to point to the inode. | |
1156 | * | |
1157 | * If inode is a directory and has a 'disconnected' dentry (i.e. IS_ROOT and | |
1158 | * DCACHE_DISCONNECTED), then d_move that in place of the given dentry | |
1159 | * and return it, else simply d_add the inode to the dentry and return NULL. | |
1160 | * | |
1161 | * This is needed in the lookup routine of any filesystem that is exportable | |
1162 | * (via knfsd) so that we can build dcache paths to directories effectively. | |
1163 | * | |
1164 | * If a dentry was found and moved, then it is returned. Otherwise NULL | |
1165 | * is returned. This matches the expected return value of ->lookup. | |
1166 | * | |
1167 | */ | |
1168 | struct dentry *d_splice_alias(struct inode *inode, struct dentry *dentry) | |
1169 | { | |
1170 | struct dentry *new = NULL; | |
1171 | ||
21c0d8fd | 1172 | if (inode && S_ISDIR(inode->i_mode)) { |
1da177e4 LT |
1173 | spin_lock(&dcache_lock); |
1174 | new = __d_find_alias(inode, 1); | |
1175 | if (new) { | |
1176 | BUG_ON(!(new->d_flags & DCACHE_DISCONNECTED)); | |
c32ccd87 | 1177 | fsnotify_d_instantiate(new, inode); |
1da177e4 LT |
1178 | spin_unlock(&dcache_lock); |
1179 | security_d_instantiate(new, inode); | |
1180 | d_rehash(dentry); | |
1181 | d_move(new, dentry); | |
1182 | iput(inode); | |
1183 | } else { | |
1184 | /* d_instantiate takes dcache_lock, so we do it by hand */ | |
1185 | list_add(&dentry->d_alias, &inode->i_dentry); | |
1186 | dentry->d_inode = inode; | |
c32ccd87 | 1187 | fsnotify_d_instantiate(dentry, inode); |
1da177e4 LT |
1188 | spin_unlock(&dcache_lock); |
1189 | security_d_instantiate(dentry, inode); | |
1190 | d_rehash(dentry); | |
1191 | } | |
1192 | } else | |
1193 | d_add(dentry, inode); | |
1194 | return new; | |
1195 | } | |
1196 | ||
1197 | ||
1198 | /** | |
1199 | * d_lookup - search for a dentry | |
1200 | * @parent: parent dentry | |
1201 | * @name: qstr of name we wish to find | |
1202 | * | |
1203 | * Searches the children of the parent dentry for the name in question. If | |
1204 | * the dentry is found its reference count is incremented and the dentry | |
1205 | * is returned. The caller must use d_put to free the entry when it has | |
1206 | * finished using it. %NULL is returned on failure. | |
1207 | * | |
1208 | * __d_lookup is dcache_lock free. The hash list is protected using RCU. | |
1209 | * Memory barriers are used while updating and doing lockless traversal. | |
1210 | * To avoid races with d_move while rename is happening, d_lock is used. | |
1211 | * | |
1212 | * Overflows in memcmp(), while d_move, are avoided by keeping the length | |
1213 | * and name pointer in one structure pointed by d_qstr. | |
1214 | * | |
1215 | * rcu_read_lock() and rcu_read_unlock() are used to disable preemption while | |
1216 | * lookup is going on. | |
1217 | * | |
1218 | * dentry_unused list is not updated even if lookup finds the required dentry | |
1219 | * in there. It is updated in places such as prune_dcache, shrink_dcache_sb, | |
1220 | * select_parent and __dget_locked. This laziness saves lookup from dcache_lock | |
1221 | * acquisition. | |
1222 | * | |
1223 | * d_lookup() is protected against the concurrent renames in some unrelated | |
1224 | * directory using the seqlockt_t rename_lock. | |
1225 | */ | |
1226 | ||
1227 | struct dentry * d_lookup(struct dentry * parent, struct qstr * name) | |
1228 | { | |
1229 | struct dentry * dentry = NULL; | |
1230 | unsigned long seq; | |
1231 | ||
1232 | do { | |
1233 | seq = read_seqbegin(&rename_lock); | |
1234 | dentry = __d_lookup(parent, name); | |
1235 | if (dentry) | |
1236 | break; | |
1237 | } while (read_seqretry(&rename_lock, seq)); | |
1238 | return dentry; | |
1239 | } | |
1240 | ||
1241 | struct dentry * __d_lookup(struct dentry * parent, struct qstr * name) | |
1242 | { | |
1243 | unsigned int len = name->len; | |
1244 | unsigned int hash = name->hash; | |
1245 | const unsigned char *str = name->name; | |
1246 | struct hlist_head *head = d_hash(parent,hash); | |
1247 | struct dentry *found = NULL; | |
1248 | struct hlist_node *node; | |
665a7583 | 1249 | struct dentry *dentry; |
1da177e4 LT |
1250 | |
1251 | rcu_read_lock(); | |
1252 | ||
665a7583 | 1253 | hlist_for_each_entry_rcu(dentry, node, head, d_hash) { |
1da177e4 LT |
1254 | struct qstr *qstr; |
1255 | ||
1da177e4 LT |
1256 | if (dentry->d_name.hash != hash) |
1257 | continue; | |
1258 | if (dentry->d_parent != parent) | |
1259 | continue; | |
1260 | ||
1261 | spin_lock(&dentry->d_lock); | |
1262 | ||
1263 | /* | |
1264 | * Recheck the dentry after taking the lock - d_move may have | |
1265 | * changed things. Don't bother checking the hash because we're | |
1266 | * about to compare the whole name anyway. | |
1267 | */ | |
1268 | if (dentry->d_parent != parent) | |
1269 | goto next; | |
1270 | ||
1271 | /* | |
1272 | * It is safe to compare names since d_move() cannot | |
1273 | * change the qstr (protected by d_lock). | |
1274 | */ | |
1275 | qstr = &dentry->d_name; | |
1276 | if (parent->d_op && parent->d_op->d_compare) { | |
1277 | if (parent->d_op->d_compare(parent, qstr, name)) | |
1278 | goto next; | |
1279 | } else { | |
1280 | if (qstr->len != len) | |
1281 | goto next; | |
1282 | if (memcmp(qstr->name, str, len)) | |
1283 | goto next; | |
1284 | } | |
1285 | ||
1286 | if (!d_unhashed(dentry)) { | |
1287 | atomic_inc(&dentry->d_count); | |
1288 | found = dentry; | |
1289 | } | |
1290 | spin_unlock(&dentry->d_lock); | |
1291 | break; | |
1292 | next: | |
1293 | spin_unlock(&dentry->d_lock); | |
1294 | } | |
1295 | rcu_read_unlock(); | |
1296 | ||
1297 | return found; | |
1298 | } | |
1299 | ||
3e7e241f EB |
1300 | /** |
1301 | * d_hash_and_lookup - hash the qstr then search for a dentry | |
1302 | * @dir: Directory to search in | |
1303 | * @name: qstr of name we wish to find | |
1304 | * | |
1305 | * On hash failure or on lookup failure NULL is returned. | |
1306 | */ | |
1307 | struct dentry *d_hash_and_lookup(struct dentry *dir, struct qstr *name) | |
1308 | { | |
1309 | struct dentry *dentry = NULL; | |
1310 | ||
1311 | /* | |
1312 | * Check for a fs-specific hash function. Note that we must | |
1313 | * calculate the standard hash first, as the d_op->d_hash() | |
1314 | * routine may choose to leave the hash value unchanged. | |
1315 | */ | |
1316 | name->hash = full_name_hash(name->name, name->len); | |
1317 | if (dir->d_op && dir->d_op->d_hash) { | |
1318 | if (dir->d_op->d_hash(dir, name) < 0) | |
1319 | goto out; | |
1320 | } | |
1321 | dentry = d_lookup(dir, name); | |
1322 | out: | |
1323 | return dentry; | |
1324 | } | |
1325 | ||
1da177e4 LT |
1326 | /** |
1327 | * d_validate - verify dentry provided from insecure source | |
1328 | * @dentry: The dentry alleged to be valid child of @dparent | |
1329 | * @dparent: The parent dentry (known to be valid) | |
1330 | * @hash: Hash of the dentry | |
1331 | * @len: Length of the name | |
1332 | * | |
1333 | * An insecure source has sent us a dentry, here we verify it and dget() it. | |
1334 | * This is used by ncpfs in its readdir implementation. | |
1335 | * Zero is returned in the dentry is invalid. | |
1336 | */ | |
1337 | ||
1338 | int d_validate(struct dentry *dentry, struct dentry *dparent) | |
1339 | { | |
1340 | struct hlist_head *base; | |
1341 | struct hlist_node *lhp; | |
1342 | ||
1343 | /* Check whether the ptr might be valid at all.. */ | |
1344 | if (!kmem_ptr_validate(dentry_cache, dentry)) | |
1345 | goto out; | |
1346 | ||
1347 | if (dentry->d_parent != dparent) | |
1348 | goto out; | |
1349 | ||
1350 | spin_lock(&dcache_lock); | |
1351 | base = d_hash(dparent, dentry->d_name.hash); | |
1352 | hlist_for_each(lhp,base) { | |
665a7583 | 1353 | /* hlist_for_each_entry_rcu() not required for d_hash list |
1da177e4 LT |
1354 | * as it is parsed under dcache_lock |
1355 | */ | |
1356 | if (dentry == hlist_entry(lhp, struct dentry, d_hash)) { | |
1357 | __dget_locked(dentry); | |
1358 | spin_unlock(&dcache_lock); | |
1359 | return 1; | |
1360 | } | |
1361 | } | |
1362 | spin_unlock(&dcache_lock); | |
1363 | out: | |
1364 | return 0; | |
1365 | } | |
1366 | ||
1367 | /* | |
1368 | * When a file is deleted, we have two options: | |
1369 | * - turn this dentry into a negative dentry | |
1370 | * - unhash this dentry and free it. | |
1371 | * | |
1372 | * Usually, we want to just turn this into | |
1373 | * a negative dentry, but if anybody else is | |
1374 | * currently using the dentry or the inode | |
1375 | * we can't do that and we fall back on removing | |
1376 | * it from the hash queues and waiting for | |
1377 | * it to be deleted later when it has no users | |
1378 | */ | |
1379 | ||
1380 | /** | |
1381 | * d_delete - delete a dentry | |
1382 | * @dentry: The dentry to delete | |
1383 | * | |
1384 | * Turn the dentry into a negative dentry if possible, otherwise | |
1385 | * remove it from the hash queues so it can be deleted later | |
1386 | */ | |
1387 | ||
1388 | void d_delete(struct dentry * dentry) | |
1389 | { | |
7a91bf7f | 1390 | int isdir = 0; |
1da177e4 LT |
1391 | /* |
1392 | * Are we the only user? | |
1393 | */ | |
1394 | spin_lock(&dcache_lock); | |
1395 | spin_lock(&dentry->d_lock); | |
7a91bf7f | 1396 | isdir = S_ISDIR(dentry->d_inode->i_mode); |
1da177e4 LT |
1397 | if (atomic_read(&dentry->d_count) == 1) { |
1398 | dentry_iput(dentry); | |
7a91bf7f | 1399 | fsnotify_nameremove(dentry, isdir); |
1da177e4 LT |
1400 | return; |
1401 | } | |
1402 | ||
1403 | if (!d_unhashed(dentry)) | |
1404 | __d_drop(dentry); | |
1405 | ||
1406 | spin_unlock(&dentry->d_lock); | |
1407 | spin_unlock(&dcache_lock); | |
7a91bf7f JM |
1408 | |
1409 | fsnotify_nameremove(dentry, isdir); | |
1da177e4 LT |
1410 | } |
1411 | ||
1412 | static void __d_rehash(struct dentry * entry, struct hlist_head *list) | |
1413 | { | |
1414 | ||
1415 | entry->d_flags &= ~DCACHE_UNHASHED; | |
1416 | hlist_add_head_rcu(&entry->d_hash, list); | |
1417 | } | |
1418 | ||
770bfad8 DH |
1419 | static void _d_rehash(struct dentry * entry) |
1420 | { | |
1421 | __d_rehash(entry, d_hash(entry->d_parent, entry->d_name.hash)); | |
1422 | } | |
1423 | ||
1da177e4 LT |
1424 | /** |
1425 | * d_rehash - add an entry back to the hash | |
1426 | * @entry: dentry to add to the hash | |
1427 | * | |
1428 | * Adds a dentry to the hash according to its name. | |
1429 | */ | |
1430 | ||
1431 | void d_rehash(struct dentry * entry) | |
1432 | { | |
1da177e4 LT |
1433 | spin_lock(&dcache_lock); |
1434 | spin_lock(&entry->d_lock); | |
770bfad8 | 1435 | _d_rehash(entry); |
1da177e4 LT |
1436 | spin_unlock(&entry->d_lock); |
1437 | spin_unlock(&dcache_lock); | |
1438 | } | |
1439 | ||
1440 | #define do_switch(x,y) do { \ | |
1441 | __typeof__ (x) __tmp = x; \ | |
1442 | x = y; y = __tmp; } while (0) | |
1443 | ||
1444 | /* | |
1445 | * When switching names, the actual string doesn't strictly have to | |
1446 | * be preserved in the target - because we're dropping the target | |
1447 | * anyway. As such, we can just do a simple memcpy() to copy over | |
1448 | * the new name before we switch. | |
1449 | * | |
1450 | * Note that we have to be a lot more careful about getting the hash | |
1451 | * switched - we have to switch the hash value properly even if it | |
1452 | * then no longer matches the actual (corrupted) string of the target. | |
1453 | * The hash value has to match the hash queue that the dentry is on.. | |
1454 | */ | |
1455 | static void switch_names(struct dentry *dentry, struct dentry *target) | |
1456 | { | |
1457 | if (dname_external(target)) { | |
1458 | if (dname_external(dentry)) { | |
1459 | /* | |
1460 | * Both external: swap the pointers | |
1461 | */ | |
1462 | do_switch(target->d_name.name, dentry->d_name.name); | |
1463 | } else { | |
1464 | /* | |
1465 | * dentry:internal, target:external. Steal target's | |
1466 | * storage and make target internal. | |
1467 | */ | |
321bcf92 BF |
1468 | memcpy(target->d_iname, dentry->d_name.name, |
1469 | dentry->d_name.len + 1); | |
1da177e4 LT |
1470 | dentry->d_name.name = target->d_name.name; |
1471 | target->d_name.name = target->d_iname; | |
1472 | } | |
1473 | } else { | |
1474 | if (dname_external(dentry)) { | |
1475 | /* | |
1476 | * dentry:external, target:internal. Give dentry's | |
1477 | * storage to target and make dentry internal | |
1478 | */ | |
1479 | memcpy(dentry->d_iname, target->d_name.name, | |
1480 | target->d_name.len + 1); | |
1481 | target->d_name.name = dentry->d_name.name; | |
1482 | dentry->d_name.name = dentry->d_iname; | |
1483 | } else { | |
1484 | /* | |
1485 | * Both are internal. Just copy target to dentry | |
1486 | */ | |
1487 | memcpy(dentry->d_iname, target->d_name.name, | |
1488 | target->d_name.len + 1); | |
1489 | } | |
1490 | } | |
1491 | } | |
1492 | ||
1493 | /* | |
1494 | * We cannibalize "target" when moving dentry on top of it, | |
1495 | * because it's going to be thrown away anyway. We could be more | |
1496 | * polite about it, though. | |
1497 | * | |
1498 | * This forceful removal will result in ugly /proc output if | |
1499 | * somebody holds a file open that got deleted due to a rename. | |
1500 | * We could be nicer about the deleted file, and let it show | |
bc154b1e BF |
1501 | * up under the name it had before it was deleted rather than |
1502 | * under the original name of the file that was moved on top of it. | |
1da177e4 LT |
1503 | */ |
1504 | ||
9eaef27b TM |
1505 | /* |
1506 | * d_move_locked - move a dentry | |
1da177e4 LT |
1507 | * @dentry: entry to move |
1508 | * @target: new dentry | |
1509 | * | |
1510 | * Update the dcache to reflect the move of a file name. Negative | |
1511 | * dcache entries should not be moved in this way. | |
1512 | */ | |
9eaef27b | 1513 | static void d_move_locked(struct dentry * dentry, struct dentry * target) |
1da177e4 LT |
1514 | { |
1515 | struct hlist_head *list; | |
1516 | ||
1517 | if (!dentry->d_inode) | |
1518 | printk(KERN_WARNING "VFS: moving negative dcache entry\n"); | |
1519 | ||
1da177e4 LT |
1520 | write_seqlock(&rename_lock); |
1521 | /* | |
1522 | * XXXX: do we really need to take target->d_lock? | |
1523 | */ | |
1524 | if (target < dentry) { | |
1525 | spin_lock(&target->d_lock); | |
a90b9c05 | 1526 | spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED); |
1da177e4 LT |
1527 | } else { |
1528 | spin_lock(&dentry->d_lock); | |
a90b9c05 | 1529 | spin_lock_nested(&target->d_lock, DENTRY_D_LOCK_NESTED); |
1da177e4 LT |
1530 | } |
1531 | ||
1532 | /* Move the dentry to the target hash queue, if on different bucket */ | |
f77e3498 | 1533 | if (d_unhashed(dentry)) |
1da177e4 LT |
1534 | goto already_unhashed; |
1535 | ||
1536 | hlist_del_rcu(&dentry->d_hash); | |
1537 | ||
1538 | already_unhashed: | |
1539 | list = d_hash(target->d_parent, target->d_name.hash); | |
1540 | __d_rehash(dentry, list); | |
1541 | ||
1542 | /* Unhash the target: dput() will then get rid of it */ | |
1543 | __d_drop(target); | |
1544 | ||
5160ee6f ED |
1545 | list_del(&dentry->d_u.d_child); |
1546 | list_del(&target->d_u.d_child); | |
1da177e4 LT |
1547 | |
1548 | /* Switch the names.. */ | |
1549 | switch_names(dentry, target); | |
1550 | do_switch(dentry->d_name.len, target->d_name.len); | |
1551 | do_switch(dentry->d_name.hash, target->d_name.hash); | |
1552 | ||
1553 | /* ... and switch the parents */ | |
1554 | if (IS_ROOT(dentry)) { | |
1555 | dentry->d_parent = target->d_parent; | |
1556 | target->d_parent = target; | |
5160ee6f | 1557 | INIT_LIST_HEAD(&target->d_u.d_child); |
1da177e4 LT |
1558 | } else { |
1559 | do_switch(dentry->d_parent, target->d_parent); | |
1560 | ||
1561 | /* And add them back to the (new) parent lists */ | |
5160ee6f | 1562 | list_add(&target->d_u.d_child, &target->d_parent->d_subdirs); |
1da177e4 LT |
1563 | } |
1564 | ||
5160ee6f | 1565 | list_add(&dentry->d_u.d_child, &dentry->d_parent->d_subdirs); |
1da177e4 | 1566 | spin_unlock(&target->d_lock); |
c32ccd87 | 1567 | fsnotify_d_move(dentry); |
1da177e4 LT |
1568 | spin_unlock(&dentry->d_lock); |
1569 | write_sequnlock(&rename_lock); | |
9eaef27b TM |
1570 | } |
1571 | ||
1572 | /** | |
1573 | * d_move - move a dentry | |
1574 | * @dentry: entry to move | |
1575 | * @target: new dentry | |
1576 | * | |
1577 | * Update the dcache to reflect the move of a file name. Negative | |
1578 | * dcache entries should not be moved in this way. | |
1579 | */ | |
1580 | ||
1581 | void d_move(struct dentry * dentry, struct dentry * target) | |
1582 | { | |
1583 | spin_lock(&dcache_lock); | |
1584 | d_move_locked(dentry, target); | |
1da177e4 LT |
1585 | spin_unlock(&dcache_lock); |
1586 | } | |
1587 | ||
9eaef27b TM |
1588 | /* |
1589 | * Helper that returns 1 if p1 is a parent of p2, else 0 | |
1590 | */ | |
1591 | static int d_isparent(struct dentry *p1, struct dentry *p2) | |
1592 | { | |
1593 | struct dentry *p; | |
1594 | ||
1595 | for (p = p2; p->d_parent != p; p = p->d_parent) { | |
1596 | if (p->d_parent == p1) | |
1597 | return 1; | |
1598 | } | |
1599 | return 0; | |
1600 | } | |
1601 | ||
1602 | /* | |
1603 | * This helper attempts to cope with remotely renamed directories | |
1604 | * | |
1605 | * It assumes that the caller is already holding | |
1606 | * dentry->d_parent->d_inode->i_mutex and the dcache_lock | |
1607 | * | |
1608 | * Note: If ever the locking in lock_rename() changes, then please | |
1609 | * remember to update this too... | |
9eaef27b TM |
1610 | */ |
1611 | static struct dentry *__d_unalias(struct dentry *dentry, struct dentry *alias) | |
31f3e0b3 | 1612 | __releases(dcache_lock) |
9eaef27b TM |
1613 | { |
1614 | struct mutex *m1 = NULL, *m2 = NULL; | |
1615 | struct dentry *ret; | |
1616 | ||
1617 | /* If alias and dentry share a parent, then no extra locks required */ | |
1618 | if (alias->d_parent == dentry->d_parent) | |
1619 | goto out_unalias; | |
1620 | ||
1621 | /* Check for loops */ | |
1622 | ret = ERR_PTR(-ELOOP); | |
1623 | if (d_isparent(alias, dentry)) | |
1624 | goto out_err; | |
1625 | ||
1626 | /* See lock_rename() */ | |
1627 | ret = ERR_PTR(-EBUSY); | |
1628 | if (!mutex_trylock(&dentry->d_sb->s_vfs_rename_mutex)) | |
1629 | goto out_err; | |
1630 | m1 = &dentry->d_sb->s_vfs_rename_mutex; | |
1631 | if (!mutex_trylock(&alias->d_parent->d_inode->i_mutex)) | |
1632 | goto out_err; | |
1633 | m2 = &alias->d_parent->d_inode->i_mutex; | |
1634 | out_unalias: | |
1635 | d_move_locked(alias, dentry); | |
1636 | ret = alias; | |
1637 | out_err: | |
1638 | spin_unlock(&dcache_lock); | |
1639 | if (m2) | |
1640 | mutex_unlock(m2); | |
1641 | if (m1) | |
1642 | mutex_unlock(m1); | |
1643 | return ret; | |
1644 | } | |
1645 | ||
770bfad8 DH |
1646 | /* |
1647 | * Prepare an anonymous dentry for life in the superblock's dentry tree as a | |
1648 | * named dentry in place of the dentry to be replaced. | |
1649 | */ | |
1650 | static void __d_materialise_dentry(struct dentry *dentry, struct dentry *anon) | |
1651 | { | |
1652 | struct dentry *dparent, *aparent; | |
1653 | ||
1654 | switch_names(dentry, anon); | |
1655 | do_switch(dentry->d_name.len, anon->d_name.len); | |
1656 | do_switch(dentry->d_name.hash, anon->d_name.hash); | |
1657 | ||
1658 | dparent = dentry->d_parent; | |
1659 | aparent = anon->d_parent; | |
1660 | ||
1661 | dentry->d_parent = (aparent == anon) ? dentry : aparent; | |
1662 | list_del(&dentry->d_u.d_child); | |
1663 | if (!IS_ROOT(dentry)) | |
1664 | list_add(&dentry->d_u.d_child, &dentry->d_parent->d_subdirs); | |
1665 | else | |
1666 | INIT_LIST_HEAD(&dentry->d_u.d_child); | |
1667 | ||
1668 | anon->d_parent = (dparent == dentry) ? anon : dparent; | |
1669 | list_del(&anon->d_u.d_child); | |
1670 | if (!IS_ROOT(anon)) | |
1671 | list_add(&anon->d_u.d_child, &anon->d_parent->d_subdirs); | |
1672 | else | |
1673 | INIT_LIST_HEAD(&anon->d_u.d_child); | |
1674 | ||
1675 | anon->d_flags &= ~DCACHE_DISCONNECTED; | |
1676 | } | |
1677 | ||
1678 | /** | |
1679 | * d_materialise_unique - introduce an inode into the tree | |
1680 | * @dentry: candidate dentry | |
1681 | * @inode: inode to bind to the dentry, to which aliases may be attached | |
1682 | * | |
1683 | * Introduces an dentry into the tree, substituting an extant disconnected | |
1684 | * root directory alias in its place if there is one | |
1685 | */ | |
1686 | struct dentry *d_materialise_unique(struct dentry *dentry, struct inode *inode) | |
1687 | { | |
9eaef27b | 1688 | struct dentry *actual; |
770bfad8 DH |
1689 | |
1690 | BUG_ON(!d_unhashed(dentry)); | |
1691 | ||
1692 | spin_lock(&dcache_lock); | |
1693 | ||
1694 | if (!inode) { | |
1695 | actual = dentry; | |
1696 | dentry->d_inode = NULL; | |
1697 | goto found_lock; | |
1698 | } | |
1699 | ||
9eaef27b TM |
1700 | if (S_ISDIR(inode->i_mode)) { |
1701 | struct dentry *alias; | |
1702 | ||
1703 | /* Does an aliased dentry already exist? */ | |
1704 | alias = __d_find_alias(inode, 0); | |
1705 | if (alias) { | |
1706 | actual = alias; | |
1707 | /* Is this an anonymous mountpoint that we could splice | |
1708 | * into our tree? */ | |
1709 | if (IS_ROOT(alias)) { | |
1710 | spin_lock(&alias->d_lock); | |
1711 | __d_materialise_dentry(dentry, alias); | |
1712 | __d_drop(alias); | |
1713 | goto found; | |
1714 | } | |
1715 | /* Nope, but we must(!) avoid directory aliasing */ | |
1716 | actual = __d_unalias(dentry, alias); | |
1717 | if (IS_ERR(actual)) | |
1718 | dput(alias); | |
1719 | goto out_nolock; | |
1720 | } | |
770bfad8 DH |
1721 | } |
1722 | ||
1723 | /* Add a unique reference */ | |
1724 | actual = __d_instantiate_unique(dentry, inode); | |
1725 | if (!actual) | |
1726 | actual = dentry; | |
1727 | else if (unlikely(!d_unhashed(actual))) | |
1728 | goto shouldnt_be_hashed; | |
1729 | ||
1730 | found_lock: | |
1731 | spin_lock(&actual->d_lock); | |
1732 | found: | |
1733 | _d_rehash(actual); | |
1734 | spin_unlock(&actual->d_lock); | |
1735 | spin_unlock(&dcache_lock); | |
9eaef27b | 1736 | out_nolock: |
770bfad8 DH |
1737 | if (actual == dentry) { |
1738 | security_d_instantiate(dentry, inode); | |
1739 | return NULL; | |
1740 | } | |
1741 | ||
1742 | iput(inode); | |
1743 | return actual; | |
1744 | ||
770bfad8 DH |
1745 | shouldnt_be_hashed: |
1746 | spin_unlock(&dcache_lock); | |
1747 | BUG(); | |
770bfad8 DH |
1748 | } |
1749 | ||
cdd16d02 | 1750 | static int prepend(char **buffer, int *buflen, const char *str, int namelen) |
6092d048 RP |
1751 | { |
1752 | *buflen -= namelen; | |
1753 | if (*buflen < 0) | |
1754 | return -ENAMETOOLONG; | |
1755 | *buffer -= namelen; | |
1756 | memcpy(*buffer, str, namelen); | |
1757 | return 0; | |
1758 | } | |
1759 | ||
cdd16d02 MS |
1760 | static int prepend_name(char **buffer, int *buflen, struct qstr *name) |
1761 | { | |
1762 | return prepend(buffer, buflen, name->name, name->len); | |
1763 | } | |
1764 | ||
1da177e4 | 1765 | /** |
31f3e0b3 | 1766 | * __d_path - return the path of a dentry |
9d1bc601 MS |
1767 | * @path: the dentry/vfsmount to report |
1768 | * @root: root vfsmnt/dentry (may be modified by this function) | |
1da177e4 LT |
1769 | * @buffer: buffer to return value in |
1770 | * @buflen: buffer length | |
1771 | * | |
552ce544 LT |
1772 | * Convert a dentry into an ASCII path name. If the entry has been deleted |
1773 | * the string " (deleted)" is appended. Note that this is ambiguous. | |
1da177e4 | 1774 | * |
552ce544 LT |
1775 | * Returns the buffer or an error code if the path was too long. |
1776 | * | |
1777 | * "buflen" should be positive. Caller holds the dcache_lock. | |
9d1bc601 MS |
1778 | * |
1779 | * If path is not reachable from the supplied root, then the value of | |
1780 | * root is changed (without modifying refcounts). | |
1da177e4 | 1781 | */ |
9d1bc601 MS |
1782 | char *__d_path(const struct path *path, struct path *root, |
1783 | char *buffer, int buflen) | |
1da177e4 | 1784 | { |
9d1bc601 MS |
1785 | struct dentry *dentry = path->dentry; |
1786 | struct vfsmount *vfsmnt = path->mnt; | |
cdd16d02 MS |
1787 | char *end = buffer + buflen; |
1788 | char *retval; | |
6092d048 | 1789 | |
be285c71 | 1790 | spin_lock(&vfsmount_lock); |
6092d048 RP |
1791 | prepend(&end, &buflen, "\0", 1); |
1792 | if (!IS_ROOT(dentry) && d_unhashed(dentry) && | |
1793 | (prepend(&end, &buflen, " (deleted)", 10) != 0)) | |
552ce544 | 1794 | goto Elong; |
552ce544 LT |
1795 | |
1796 | if (buflen < 1) | |
1797 | goto Elong; | |
1798 | /* Get '/' right */ | |
1799 | retval = end-1; | |
1800 | *retval = '/'; | |
1801 | ||
1802 | for (;;) { | |
1da177e4 LT |
1803 | struct dentry * parent; |
1804 | ||
329c97f0 | 1805 | if (dentry == root->dentry && vfsmnt == root->mnt) |
552ce544 | 1806 | break; |
1da177e4 | 1807 | if (dentry == vfsmnt->mnt_root || IS_ROOT(dentry)) { |
552ce544 | 1808 | /* Global root? */ |
1da177e4 | 1809 | if (vfsmnt->mnt_parent == vfsmnt) { |
1da177e4 LT |
1810 | goto global_root; |
1811 | } | |
1812 | dentry = vfsmnt->mnt_mountpoint; | |
1813 | vfsmnt = vfsmnt->mnt_parent; | |
1da177e4 LT |
1814 | continue; |
1815 | } | |
1816 | parent = dentry->d_parent; | |
1817 | prefetch(parent); | |
cdd16d02 | 1818 | if ((prepend_name(&end, &buflen, &dentry->d_name) != 0) || |
6092d048 | 1819 | (prepend(&end, &buflen, "/", 1) != 0)) |
552ce544 | 1820 | goto Elong; |
552ce544 | 1821 | retval = end; |
1da177e4 LT |
1822 | dentry = parent; |
1823 | } | |
1824 | ||
be285c71 AG |
1825 | out: |
1826 | spin_unlock(&vfsmount_lock); | |
552ce544 | 1827 | return retval; |
1da177e4 LT |
1828 | |
1829 | global_root: | |
6092d048 | 1830 | retval += 1; /* hit the slash */ |
cdd16d02 | 1831 | if (prepend_name(&retval, &buflen, &dentry->d_name) != 0) |
1da177e4 | 1832 | goto Elong; |
9d1bc601 MS |
1833 | root->mnt = vfsmnt; |
1834 | root->dentry = dentry; | |
be285c71 AG |
1835 | goto out; |
1836 | ||
1da177e4 | 1837 | Elong: |
be285c71 AG |
1838 | retval = ERR_PTR(-ENAMETOOLONG); |
1839 | goto out; | |
1da177e4 LT |
1840 | } |
1841 | ||
a03a8a70 JB |
1842 | /** |
1843 | * d_path - return the path of a dentry | |
cf28b486 | 1844 | * @path: path to report |
a03a8a70 JB |
1845 | * @buf: buffer to return value in |
1846 | * @buflen: buffer length | |
1847 | * | |
1848 | * Convert a dentry into an ASCII path name. If the entry has been deleted | |
1849 | * the string " (deleted)" is appended. Note that this is ambiguous. | |
1850 | * | |
1851 | * Returns the buffer or an error code if the path was too long. | |
1852 | * | |
31f3e0b3 | 1853 | * "buflen" should be positive. |
a03a8a70 | 1854 | */ |
20d4fdc1 | 1855 | char *d_path(const struct path *path, char *buf, int buflen) |
1da177e4 LT |
1856 | { |
1857 | char *res; | |
6ac08c39 | 1858 | struct path root; |
9d1bc601 | 1859 | struct path tmp; |
1da177e4 | 1860 | |
c23fbb6b ED |
1861 | /* |
1862 | * We have various synthetic filesystems that never get mounted. On | |
1863 | * these filesystems dentries are never used for lookup purposes, and | |
1864 | * thus don't need to be hashed. They also don't need a name until a | |
1865 | * user wants to identify the object in /proc/pid/fd/. The little hack | |
1866 | * below allows us to generate a name for these objects on demand: | |
1867 | */ | |
cf28b486 JB |
1868 | if (path->dentry->d_op && path->dentry->d_op->d_dname) |
1869 | return path->dentry->d_op->d_dname(path->dentry, buf, buflen); | |
c23fbb6b | 1870 | |
1da177e4 | 1871 | read_lock(¤t->fs->lock); |
6ac08c39 | 1872 | root = current->fs->root; |
6092d048 | 1873 | path_get(&root); |
1da177e4 | 1874 | read_unlock(¤t->fs->lock); |
552ce544 | 1875 | spin_lock(&dcache_lock); |
9d1bc601 MS |
1876 | tmp = root; |
1877 | res = __d_path(path, &tmp, buf, buflen); | |
552ce544 | 1878 | spin_unlock(&dcache_lock); |
6ac08c39 | 1879 | path_put(&root); |
1da177e4 LT |
1880 | return res; |
1881 | } | |
1882 | ||
c23fbb6b ED |
1883 | /* |
1884 | * Helper function for dentry_operations.d_dname() members | |
1885 | */ | |
1886 | char *dynamic_dname(struct dentry *dentry, char *buffer, int buflen, | |
1887 | const char *fmt, ...) | |
1888 | { | |
1889 | va_list args; | |
1890 | char temp[64]; | |
1891 | int sz; | |
1892 | ||
1893 | va_start(args, fmt); | |
1894 | sz = vsnprintf(temp, sizeof(temp), fmt, args) + 1; | |
1895 | va_end(args); | |
1896 | ||
1897 | if (sz > sizeof(temp) || sz > buflen) | |
1898 | return ERR_PTR(-ENAMETOOLONG); | |
1899 | ||
1900 | buffer += buflen - sz; | |
1901 | return memcpy(buffer, temp, sz); | |
1902 | } | |
1903 | ||
6092d048 RP |
1904 | /* |
1905 | * Write full pathname from the root of the filesystem into the buffer. | |
1906 | */ | |
1907 | char *dentry_path(struct dentry *dentry, char *buf, int buflen) | |
1908 | { | |
1909 | char *end = buf + buflen; | |
1910 | char *retval; | |
1911 | ||
1912 | spin_lock(&dcache_lock); | |
1913 | prepend(&end, &buflen, "\0", 1); | |
1914 | if (!IS_ROOT(dentry) && d_unhashed(dentry) && | |
1915 | (prepend(&end, &buflen, "//deleted", 9) != 0)) | |
1916 | goto Elong; | |
1917 | if (buflen < 1) | |
1918 | goto Elong; | |
1919 | /* Get '/' right */ | |
1920 | retval = end-1; | |
1921 | *retval = '/'; | |
1922 | ||
cdd16d02 MS |
1923 | while (!IS_ROOT(dentry)) { |
1924 | struct dentry *parent = dentry->d_parent; | |
6092d048 | 1925 | |
6092d048 | 1926 | prefetch(parent); |
cdd16d02 | 1927 | if ((prepend_name(&end, &buflen, &dentry->d_name) != 0) || |
6092d048 RP |
1928 | (prepend(&end, &buflen, "/", 1) != 0)) |
1929 | goto Elong; | |
1930 | ||
1931 | retval = end; | |
1932 | dentry = parent; | |
1933 | } | |
1934 | spin_unlock(&dcache_lock); | |
1935 | return retval; | |
1936 | Elong: | |
1937 | spin_unlock(&dcache_lock); | |
1938 | return ERR_PTR(-ENAMETOOLONG); | |
1939 | } | |
1940 | ||
1da177e4 LT |
1941 | /* |
1942 | * NOTE! The user-level library version returns a | |
1943 | * character pointer. The kernel system call just | |
1944 | * returns the length of the buffer filled (which | |
1945 | * includes the ending '\0' character), or a negative | |
1946 | * error value. So libc would do something like | |
1947 | * | |
1948 | * char *getcwd(char * buf, size_t size) | |
1949 | * { | |
1950 | * int retval; | |
1951 | * | |
1952 | * retval = sys_getcwd(buf, size); | |
1953 | * if (retval >= 0) | |
1954 | * return buf; | |
1955 | * errno = -retval; | |
1956 | * return NULL; | |
1957 | * } | |
1958 | */ | |
1959 | asmlinkage long sys_getcwd(char __user *buf, unsigned long size) | |
1960 | { | |
552ce544 | 1961 | int error; |
6ac08c39 | 1962 | struct path pwd, root; |
552ce544 | 1963 | char *page = (char *) __get_free_page(GFP_USER); |
1da177e4 LT |
1964 | |
1965 | if (!page) | |
1966 | return -ENOMEM; | |
1967 | ||
1968 | read_lock(¤t->fs->lock); | |
6ac08c39 | 1969 | pwd = current->fs->pwd; |
6092d048 | 1970 | path_get(&pwd); |
6ac08c39 | 1971 | root = current->fs->root; |
6092d048 | 1972 | path_get(&root); |
1da177e4 LT |
1973 | read_unlock(¤t->fs->lock); |
1974 | ||
552ce544 LT |
1975 | error = -ENOENT; |
1976 | /* Has the current directory has been unlinked? */ | |
1977 | spin_lock(&dcache_lock); | |
cdd16d02 | 1978 | if (IS_ROOT(pwd.dentry) || !d_unhashed(pwd.dentry)) { |
552ce544 | 1979 | unsigned long len; |
9d1bc601 | 1980 | struct path tmp = root; |
552ce544 | 1981 | char * cwd; |
1da177e4 | 1982 | |
9d1bc601 | 1983 | cwd = __d_path(&pwd, &tmp, page, PAGE_SIZE); |
552ce544 LT |
1984 | spin_unlock(&dcache_lock); |
1985 | ||
1986 | error = PTR_ERR(cwd); | |
1987 | if (IS_ERR(cwd)) | |
1988 | goto out; | |
1989 | ||
1990 | error = -ERANGE; | |
1991 | len = PAGE_SIZE + page - cwd; | |
1992 | if (len <= size) { | |
1993 | error = len; | |
1994 | if (copy_to_user(buf, cwd, len)) | |
1995 | error = -EFAULT; | |
1996 | } | |
1997 | } else | |
1998 | spin_unlock(&dcache_lock); | |
1da177e4 LT |
1999 | |
2000 | out: | |
6ac08c39 JB |
2001 | path_put(&pwd); |
2002 | path_put(&root); | |
1da177e4 LT |
2003 | free_page((unsigned long) page); |
2004 | return error; | |
2005 | } | |
2006 | ||
2007 | /* | |
2008 | * Test whether new_dentry is a subdirectory of old_dentry. | |
2009 | * | |
2010 | * Trivially implemented using the dcache structure | |
2011 | */ | |
2012 | ||
2013 | /** | |
2014 | * is_subdir - is new dentry a subdirectory of old_dentry | |
2015 | * @new_dentry: new dentry | |
2016 | * @old_dentry: old dentry | |
2017 | * | |
2018 | * Returns 1 if new_dentry is a subdirectory of the parent (at any depth). | |
2019 | * Returns 0 otherwise. | |
2020 | * Caller must ensure that "new_dentry" is pinned before calling is_subdir() | |
2021 | */ | |
2022 | ||
2023 | int is_subdir(struct dentry * new_dentry, struct dentry * old_dentry) | |
2024 | { | |
2025 | int result; | |
2026 | struct dentry * saved = new_dentry; | |
2027 | unsigned long seq; | |
2028 | ||
2029 | /* need rcu_readlock to protect against the d_parent trashing due to | |
2030 | * d_move | |
2031 | */ | |
2032 | rcu_read_lock(); | |
2033 | do { | |
2034 | /* for restarting inner loop in case of seq retry */ | |
2035 | new_dentry = saved; | |
2036 | result = 0; | |
2037 | seq = read_seqbegin(&rename_lock); | |
2038 | for (;;) { | |
2039 | if (new_dentry != old_dentry) { | |
2040 | struct dentry * parent = new_dentry->d_parent; | |
2041 | if (parent == new_dentry) | |
2042 | break; | |
2043 | new_dentry = parent; | |
2044 | continue; | |
2045 | } | |
2046 | result = 1; | |
2047 | break; | |
2048 | } | |
2049 | } while (read_seqretry(&rename_lock, seq)); | |
2050 | rcu_read_unlock(); | |
2051 | ||
2052 | return result; | |
2053 | } | |
2054 | ||
2055 | void d_genocide(struct dentry *root) | |
2056 | { | |
2057 | struct dentry *this_parent = root; | |
2058 | struct list_head *next; | |
2059 | ||
2060 | spin_lock(&dcache_lock); | |
2061 | repeat: | |
2062 | next = this_parent->d_subdirs.next; | |
2063 | resume: | |
2064 | while (next != &this_parent->d_subdirs) { | |
2065 | struct list_head *tmp = next; | |
5160ee6f | 2066 | struct dentry *dentry = list_entry(tmp, struct dentry, d_u.d_child); |
1da177e4 LT |
2067 | next = tmp->next; |
2068 | if (d_unhashed(dentry)||!dentry->d_inode) | |
2069 | continue; | |
2070 | if (!list_empty(&dentry->d_subdirs)) { | |
2071 | this_parent = dentry; | |
2072 | goto repeat; | |
2073 | } | |
2074 | atomic_dec(&dentry->d_count); | |
2075 | } | |
2076 | if (this_parent != root) { | |
5160ee6f | 2077 | next = this_parent->d_u.d_child.next; |
1da177e4 LT |
2078 | atomic_dec(&this_parent->d_count); |
2079 | this_parent = this_parent->d_parent; | |
2080 | goto resume; | |
2081 | } | |
2082 | spin_unlock(&dcache_lock); | |
2083 | } | |
2084 | ||
2085 | /** | |
2086 | * find_inode_number - check for dentry with name | |
2087 | * @dir: directory to check | |
2088 | * @name: Name to find. | |
2089 | * | |
2090 | * Check whether a dentry already exists for the given name, | |
2091 | * and return the inode number if it has an inode. Otherwise | |
2092 | * 0 is returned. | |
2093 | * | |
2094 | * This routine is used to post-process directory listings for | |
2095 | * filesystems using synthetic inode numbers, and is necessary | |
2096 | * to keep getcwd() working. | |
2097 | */ | |
2098 | ||
2099 | ino_t find_inode_number(struct dentry *dir, struct qstr *name) | |
2100 | { | |
2101 | struct dentry * dentry; | |
2102 | ino_t ino = 0; | |
2103 | ||
3e7e241f EB |
2104 | dentry = d_hash_and_lookup(dir, name); |
2105 | if (dentry) { | |
1da177e4 LT |
2106 | if (dentry->d_inode) |
2107 | ino = dentry->d_inode->i_ino; | |
2108 | dput(dentry); | |
2109 | } | |
1da177e4 LT |
2110 | return ino; |
2111 | } | |
2112 | ||
2113 | static __initdata unsigned long dhash_entries; | |
2114 | static int __init set_dhash_entries(char *str) | |
2115 | { | |
2116 | if (!str) | |
2117 | return 0; | |
2118 | dhash_entries = simple_strtoul(str, &str, 0); | |
2119 | return 1; | |
2120 | } | |
2121 | __setup("dhash_entries=", set_dhash_entries); | |
2122 | ||
2123 | static void __init dcache_init_early(void) | |
2124 | { | |
2125 | int loop; | |
2126 | ||
2127 | /* If hashes are distributed across NUMA nodes, defer | |
2128 | * hash allocation until vmalloc space is available. | |
2129 | */ | |
2130 | if (hashdist) | |
2131 | return; | |
2132 | ||
2133 | dentry_hashtable = | |
2134 | alloc_large_system_hash("Dentry cache", | |
2135 | sizeof(struct hlist_head), | |
2136 | dhash_entries, | |
2137 | 13, | |
2138 | HASH_EARLY, | |
2139 | &d_hash_shift, | |
2140 | &d_hash_mask, | |
2141 | 0); | |
2142 | ||
2143 | for (loop = 0; loop < (1 << d_hash_shift); loop++) | |
2144 | INIT_HLIST_HEAD(&dentry_hashtable[loop]); | |
2145 | } | |
2146 | ||
74bf17cf | 2147 | static void __init dcache_init(void) |
1da177e4 LT |
2148 | { |
2149 | int loop; | |
2150 | ||
2151 | /* | |
2152 | * A constructor could be added for stable state like the lists, | |
2153 | * but it is probably not worth it because of the cache nature | |
2154 | * of the dcache. | |
2155 | */ | |
0a31bd5f CL |
2156 | dentry_cache = KMEM_CACHE(dentry, |
2157 | SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|SLAB_MEM_SPREAD); | |
1da177e4 | 2158 | |
8e1f936b | 2159 | register_shrinker(&dcache_shrinker); |
1da177e4 LT |
2160 | |
2161 | /* Hash may have been set up in dcache_init_early */ | |
2162 | if (!hashdist) | |
2163 | return; | |
2164 | ||
2165 | dentry_hashtable = | |
2166 | alloc_large_system_hash("Dentry cache", | |
2167 | sizeof(struct hlist_head), | |
2168 | dhash_entries, | |
2169 | 13, | |
2170 | 0, | |
2171 | &d_hash_shift, | |
2172 | &d_hash_mask, | |
2173 | 0); | |
2174 | ||
2175 | for (loop = 0; loop < (1 << d_hash_shift); loop++) | |
2176 | INIT_HLIST_HEAD(&dentry_hashtable[loop]); | |
2177 | } | |
2178 | ||
2179 | /* SLAB cache for __getname() consumers */ | |
e18b890b | 2180 | struct kmem_cache *names_cachep __read_mostly; |
1da177e4 LT |
2181 | |
2182 | /* SLAB cache for file structures */ | |
e18b890b | 2183 | struct kmem_cache *filp_cachep __read_mostly; |
1da177e4 LT |
2184 | |
2185 | EXPORT_SYMBOL(d_genocide); | |
2186 | ||
1da177e4 LT |
2187 | void __init vfs_caches_init_early(void) |
2188 | { | |
2189 | dcache_init_early(); | |
2190 | inode_init_early(); | |
2191 | } | |
2192 | ||
2193 | void __init vfs_caches_init(unsigned long mempages) | |
2194 | { | |
2195 | unsigned long reserve; | |
2196 | ||
2197 | /* Base hash sizes on available memory, with a reserve equal to | |
2198 | 150% of current kernel size */ | |
2199 | ||
2200 | reserve = min((mempages - nr_free_pages()) * 3/2, mempages - 1); | |
2201 | mempages -= reserve; | |
2202 | ||
2203 | names_cachep = kmem_cache_create("names_cache", PATH_MAX, 0, | |
20c2df83 | 2204 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |
1da177e4 LT |
2205 | |
2206 | filp_cachep = kmem_cache_create("filp", sizeof(struct file), 0, | |
20c2df83 | 2207 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |
1da177e4 | 2208 | |
74bf17cf DC |
2209 | dcache_init(); |
2210 | inode_init(); | |
1da177e4 | 2211 | files_init(mempages); |
74bf17cf | 2212 | mnt_init(); |
1da177e4 LT |
2213 | bdev_cache_init(); |
2214 | chrdev_init(); | |
2215 | } | |
2216 | ||
2217 | EXPORT_SYMBOL(d_alloc); | |
2218 | EXPORT_SYMBOL(d_alloc_anon); | |
2219 | EXPORT_SYMBOL(d_alloc_root); | |
2220 | EXPORT_SYMBOL(d_delete); | |
2221 | EXPORT_SYMBOL(d_find_alias); | |
2222 | EXPORT_SYMBOL(d_instantiate); | |
2223 | EXPORT_SYMBOL(d_invalidate); | |
2224 | EXPORT_SYMBOL(d_lookup); | |
2225 | EXPORT_SYMBOL(d_move); | |
770bfad8 | 2226 | EXPORT_SYMBOL_GPL(d_materialise_unique); |
1da177e4 LT |
2227 | EXPORT_SYMBOL(d_path); |
2228 | EXPORT_SYMBOL(d_prune_aliases); | |
2229 | EXPORT_SYMBOL(d_rehash); | |
2230 | EXPORT_SYMBOL(d_splice_alias); | |
2231 | EXPORT_SYMBOL(d_validate); | |
2232 | EXPORT_SYMBOL(dget_locked); | |
2233 | EXPORT_SYMBOL(dput); | |
2234 | EXPORT_SYMBOL(find_inode_number); | |
2235 | EXPORT_SYMBOL(have_submounts); | |
2236 | EXPORT_SYMBOL(names_cachep); | |
2237 | EXPORT_SYMBOL(shrink_dcache_parent); | |
2238 | EXPORT_SYMBOL(shrink_dcache_sb); |