4 * Complete reimplementation
5 * (C) 1997 Thomas Schoebel-Theuer,
6 * with heavy changes by Linus Torvalds
10 * Notes on the allocation strategy:
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.
17 #include <linux/config.h>
18 #include <linux/syscalls.h>
19 #include <linux/string.h>
22 #include <linux/fsnotify.h>
23 #include <linux/slab.h>
24 #include <linux/init.h>
25 #include <linux/smp_lock.h>
26 #include <linux/hash.h>
27 #include <linux/cache.h>
28 #include <linux/module.h>
29 #include <linux/mount.h>
30 #include <linux/file.h>
31 #include <asm/uaccess.h>
32 #include <linux/security.h>
33 #include <linux/seqlock.h>
34 #include <linux/swap.h>
35 #include <linux/bootmem.h>
38 int sysctl_vfs_cache_pressure __read_mostly
= 100;
39 EXPORT_SYMBOL_GPL(sysctl_vfs_cache_pressure
);
41 __cacheline_aligned_in_smp
DEFINE_SPINLOCK(dcache_lock
);
42 static seqlock_t rename_lock __cacheline_aligned_in_smp
= SEQLOCK_UNLOCKED
;
44 EXPORT_SYMBOL(dcache_lock
);
46 static kmem_cache_t
*dentry_cache __read_mostly
;
48 #define DNAME_INLINE_LEN (sizeof(struct dentry)-offsetof(struct dentry,d_iname))
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.
55 * This hash-function tries to avoid losing too many bits of hash
56 * information, yet avoid using a prime hash-size or similar.
58 #define D_HASHBITS d_hash_shift
59 #define D_HASHMASK d_hash_mask
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
;
64 static LIST_HEAD(dentry_unused
);
66 /* Statistics gathering. */
67 struct dentry_stat_t dentry_stat
= {
71 static void d_callback(struct rcu_head
*head
)
73 struct dentry
* dentry
= container_of(head
, struct dentry
, d_u
.d_rcu
);
75 if (dname_external(dentry
))
76 kfree(dentry
->d_name
.name
);
77 kmem_cache_free(dentry_cache
, dentry
);
81 * no dcache_lock, please. The caller must decrement dentry_stat.nr_dentry
84 static void d_free(struct dentry
*dentry
)
86 if (dentry
->d_op
&& dentry
->d_op
->d_release
)
87 dentry
->d_op
->d_release(dentry
);
88 call_rcu(&dentry
->d_u
.d_rcu
, d_callback
);
92 * Release the dentry's inode, using the filesystem
93 * d_iput() operation if defined.
94 * Called with dcache_lock and per dentry lock held, drops both.
96 static void dentry_iput(struct dentry
* dentry
)
98 struct inode
*inode
= dentry
->d_inode
;
100 dentry
->d_inode
= NULL
;
101 list_del_init(&dentry
->d_alias
);
102 spin_unlock(&dentry
->d_lock
);
103 spin_unlock(&dcache_lock
);
105 fsnotify_inoderemove(inode
);
106 if (dentry
->d_op
&& dentry
->d_op
->d_iput
)
107 dentry
->d_op
->d_iput(dentry
, inode
);
111 spin_unlock(&dentry
->d_lock
);
112 spin_unlock(&dcache_lock
);
119 * This is complicated by the fact that we do not want to put
120 * dentries that are no longer on any hash chain on the unused
121 * list: we'd much rather just get rid of them immediately.
123 * However, that implies that we have to traverse the dentry
124 * tree upwards to the parents which might _also_ now be
125 * scheduled for deletion (it may have been only waiting for
126 * its last child to go away).
128 * This tail recursion is done by hand as we don't want to depend
129 * on the compiler to always get this right (gcc generally doesn't).
130 * Real recursion would eat up our stack space.
134 * dput - release a dentry
135 * @dentry: dentry to release
137 * Release a dentry. This will drop the usage count and if appropriate
138 * call the dentry unlink method as well as removing it from the queues and
139 * releasing its resources. If the parent dentries were scheduled for release
140 * they too may now get deleted.
142 * no dcache lock, please.
145 void dput(struct dentry
*dentry
)
151 if (atomic_read(&dentry
->d_count
) == 1)
153 if (!atomic_dec_and_lock(&dentry
->d_count
, &dcache_lock
))
156 spin_lock(&dentry
->d_lock
);
157 if (atomic_read(&dentry
->d_count
)) {
158 spin_unlock(&dentry
->d_lock
);
159 spin_unlock(&dcache_lock
);
164 * AV: ->d_delete() is _NOT_ allowed to block now.
166 if (dentry
->d_op
&& dentry
->d_op
->d_delete
) {
167 if (dentry
->d_op
->d_delete(dentry
))
170 /* Unreachable? Get rid of it */
171 if (d_unhashed(dentry
))
173 if (list_empty(&dentry
->d_lru
)) {
174 dentry
->d_flags
|= DCACHE_REFERENCED
;
175 list_add(&dentry
->d_lru
, &dentry_unused
);
176 dentry_stat
.nr_unused
++;
178 spin_unlock(&dentry
->d_lock
);
179 spin_unlock(&dcache_lock
);
186 struct dentry
*parent
;
188 /* If dentry was on d_lru list
189 * delete it from there
191 if (!list_empty(&dentry
->d_lru
)) {
192 list_del(&dentry
->d_lru
);
193 dentry_stat
.nr_unused
--;
195 list_del(&dentry
->d_u
.d_child
);
196 dentry_stat
.nr_dentry
--; /* For d_free, below */
197 /*drops the locks, at that point nobody can reach this dentry */
199 parent
= dentry
->d_parent
;
201 if (dentry
== parent
)
209 * d_invalidate - invalidate a dentry
210 * @dentry: dentry to invalidate
212 * Try to invalidate the dentry if it turns out to be
213 * possible. If there are other dentries that can be
214 * reached through this one we can't delete it and we
215 * return -EBUSY. On success we return 0.
220 int d_invalidate(struct dentry
* dentry
)
223 * If it's already been dropped, return OK.
225 spin_lock(&dcache_lock
);
226 if (d_unhashed(dentry
)) {
227 spin_unlock(&dcache_lock
);
231 * Check whether to do a partial shrink_dcache
232 * to get rid of unused child entries.
234 if (!list_empty(&dentry
->d_subdirs
)) {
235 spin_unlock(&dcache_lock
);
236 shrink_dcache_parent(dentry
);
237 spin_lock(&dcache_lock
);
241 * Somebody else still using it?
243 * If it's a directory, we can't drop it
244 * for fear of somebody re-populating it
245 * with children (even though dropping it
246 * would make it unreachable from the root,
247 * we might still populate it if it was a
248 * working directory or similar).
250 spin_lock(&dentry
->d_lock
);
251 if (atomic_read(&dentry
->d_count
) > 1) {
252 if (dentry
->d_inode
&& S_ISDIR(dentry
->d_inode
->i_mode
)) {
253 spin_unlock(&dentry
->d_lock
);
254 spin_unlock(&dcache_lock
);
260 spin_unlock(&dentry
->d_lock
);
261 spin_unlock(&dcache_lock
);
265 /* This should be called _only_ with dcache_lock held */
267 static inline struct dentry
* __dget_locked(struct dentry
*dentry
)
269 atomic_inc(&dentry
->d_count
);
270 if (!list_empty(&dentry
->d_lru
)) {
271 dentry_stat
.nr_unused
--;
272 list_del_init(&dentry
->d_lru
);
277 struct dentry
* dget_locked(struct dentry
*dentry
)
279 return __dget_locked(dentry
);
283 * d_find_alias - grab a hashed alias of inode
284 * @inode: inode in question
285 * @want_discon: flag, used by d_splice_alias, to request
286 * that only a DISCONNECTED alias be returned.
288 * If inode has a hashed alias, or is a directory and has any alias,
289 * acquire the reference to alias and return it. Otherwise return NULL.
290 * Notice that if inode is a directory there can be only one alias and
291 * it can be unhashed only if it has no children, or if it is the root
294 * If the inode has a DCACHE_DISCONNECTED alias, then prefer
295 * any other hashed alias over that one unless @want_discon is set,
296 * in which case only return a DCACHE_DISCONNECTED alias.
299 static struct dentry
* __d_find_alias(struct inode
*inode
, int want_discon
)
301 struct list_head
*head
, *next
, *tmp
;
302 struct dentry
*alias
, *discon_alias
=NULL
;
304 head
= &inode
->i_dentry
;
305 next
= inode
->i_dentry
.next
;
306 while (next
!= head
) {
310 alias
= list_entry(tmp
, struct dentry
, d_alias
);
311 if (S_ISDIR(inode
->i_mode
) || !d_unhashed(alias
)) {
312 if (alias
->d_flags
& DCACHE_DISCONNECTED
)
313 discon_alias
= alias
;
314 else if (!want_discon
) {
315 __dget_locked(alias
);
321 __dget_locked(discon_alias
);
325 struct dentry
* d_find_alias(struct inode
*inode
)
327 struct dentry
*de
= NULL
;
329 if (!list_empty(&inode
->i_dentry
)) {
330 spin_lock(&dcache_lock
);
331 de
= __d_find_alias(inode
, 0);
332 spin_unlock(&dcache_lock
);
338 * Try to kill dentries associated with this inode.
339 * WARNING: you must own a reference to inode.
341 void d_prune_aliases(struct inode
*inode
)
343 struct dentry
*dentry
;
345 spin_lock(&dcache_lock
);
346 list_for_each_entry(dentry
, &inode
->i_dentry
, d_alias
) {
347 spin_lock(&dentry
->d_lock
);
348 if (!atomic_read(&dentry
->d_count
)) {
349 __dget_locked(dentry
);
351 spin_unlock(&dentry
->d_lock
);
352 spin_unlock(&dcache_lock
);
356 spin_unlock(&dentry
->d_lock
);
358 spin_unlock(&dcache_lock
);
362 * Throw away a dentry - free the inode, dput the parent.
363 * This requires that the LRU list has already been
365 * Called with dcache_lock, drops it and then regains.
367 static inline void prune_one_dentry(struct dentry
* dentry
)
369 struct dentry
* parent
;
372 list_del(&dentry
->d_u
.d_child
);
373 dentry_stat
.nr_dentry
--; /* For d_free, below */
375 parent
= dentry
->d_parent
;
377 if (parent
!= dentry
)
379 spin_lock(&dcache_lock
);
383 * prune_dcache - shrink the dcache
384 * @count: number of entries to try and free
386 * Shrink the dcache. This is done when we need
387 * more memory, or simply when we need to unmount
388 * something (at which point we need to unuse
391 * This function may fail to free any resources if
392 * all the dentries are in use.
395 static void prune_dcache(int count
)
397 spin_lock(&dcache_lock
);
398 for (; count
; count
--) {
399 struct dentry
*dentry
;
400 struct list_head
*tmp
;
402 cond_resched_lock(&dcache_lock
);
404 tmp
= dentry_unused
.prev
;
405 if (tmp
== &dentry_unused
)
408 prefetch(dentry_unused
.prev
);
409 dentry_stat
.nr_unused
--;
410 dentry
= list_entry(tmp
, struct dentry
, d_lru
);
412 spin_lock(&dentry
->d_lock
);
414 * We found an inuse dentry which was not removed from
415 * dentry_unused because of laziness during lookup. Do not free
416 * it - just keep it off the dentry_unused list.
418 if (atomic_read(&dentry
->d_count
)) {
419 spin_unlock(&dentry
->d_lock
);
422 /* If the dentry was recently referenced, don't free it. */
423 if (dentry
->d_flags
& DCACHE_REFERENCED
) {
424 dentry
->d_flags
&= ~DCACHE_REFERENCED
;
425 list_add(&dentry
->d_lru
, &dentry_unused
);
426 dentry_stat
.nr_unused
++;
427 spin_unlock(&dentry
->d_lock
);
430 prune_one_dentry(dentry
);
432 spin_unlock(&dcache_lock
);
436 * Shrink the dcache for the specified super block.
437 * This allows us to unmount a device without disturbing
438 * the dcache for the other devices.
440 * This implementation makes just two traversals of the
441 * unused list. On the first pass we move the selected
442 * dentries to the most recent end, and on the second
443 * pass we free them. The second pass must restart after
444 * each dput(), but since the target dentries are all at
445 * the end, it's really just a single traversal.
449 * shrink_dcache_sb - shrink dcache for a superblock
452 * Shrink the dcache for the specified super block. This
453 * is used to free the dcache before unmounting a file
457 void shrink_dcache_sb(struct super_block
* sb
)
459 struct list_head
*tmp
, *next
;
460 struct dentry
*dentry
;
463 * Pass one ... move the dentries for the specified
464 * superblock to the most recent end of the unused list.
466 spin_lock(&dcache_lock
);
467 list_for_each_safe(tmp
, next
, &dentry_unused
) {
468 dentry
= list_entry(tmp
, struct dentry
, d_lru
);
469 if (dentry
->d_sb
!= sb
)
472 list_add(tmp
, &dentry_unused
);
476 * Pass two ... free the dentries for this superblock.
479 list_for_each_safe(tmp
, next
, &dentry_unused
) {
480 dentry
= list_entry(tmp
, struct dentry
, d_lru
);
481 if (dentry
->d_sb
!= sb
)
483 dentry_stat
.nr_unused
--;
485 spin_lock(&dentry
->d_lock
);
486 if (atomic_read(&dentry
->d_count
)) {
487 spin_unlock(&dentry
->d_lock
);
490 prune_one_dentry(dentry
);
491 cond_resched_lock(&dcache_lock
);
494 spin_unlock(&dcache_lock
);
498 * Search for at least 1 mount point in the dentry's subdirs.
499 * We descend to the next level whenever the d_subdirs
500 * list is non-empty and continue searching.
504 * have_submounts - check for mounts over a dentry
505 * @parent: dentry to check.
507 * Return true if the parent or its subdirectories contain
511 int have_submounts(struct dentry
*parent
)
513 struct dentry
*this_parent
= parent
;
514 struct list_head
*next
;
516 spin_lock(&dcache_lock
);
517 if (d_mountpoint(parent
))
520 next
= this_parent
->d_subdirs
.next
;
522 while (next
!= &this_parent
->d_subdirs
) {
523 struct list_head
*tmp
= next
;
524 struct dentry
*dentry
= list_entry(tmp
, struct dentry
, d_u
.d_child
);
526 /* Have we found a mount point ? */
527 if (d_mountpoint(dentry
))
529 if (!list_empty(&dentry
->d_subdirs
)) {
530 this_parent
= dentry
;
535 * All done at this level ... ascend and resume the search.
537 if (this_parent
!= parent
) {
538 next
= this_parent
->d_u
.d_child
.next
;
539 this_parent
= this_parent
->d_parent
;
542 spin_unlock(&dcache_lock
);
543 return 0; /* No mount points found in tree */
545 spin_unlock(&dcache_lock
);
550 * Search the dentry child list for the specified parent,
551 * and move any unused dentries to the end of the unused
552 * list for prune_dcache(). We descend to the next level
553 * whenever the d_subdirs list is non-empty and continue
556 * It returns zero iff there are no unused children,
557 * otherwise it returns the number of children moved to
558 * the end of the unused list. This may not be the total
559 * number of unused children, because select_parent can
560 * drop the lock and return early due to latency
563 static int select_parent(struct dentry
* parent
)
565 struct dentry
*this_parent
= parent
;
566 struct list_head
*next
;
569 spin_lock(&dcache_lock
);
571 next
= this_parent
->d_subdirs
.next
;
573 while (next
!= &this_parent
->d_subdirs
) {
574 struct list_head
*tmp
= next
;
575 struct dentry
*dentry
= list_entry(tmp
, struct dentry
, d_u
.d_child
);
578 if (!list_empty(&dentry
->d_lru
)) {
579 dentry_stat
.nr_unused
--;
580 list_del_init(&dentry
->d_lru
);
583 * move only zero ref count dentries to the end
584 * of the unused list for prune_dcache
586 if (!atomic_read(&dentry
->d_count
)) {
587 list_add(&dentry
->d_lru
, dentry_unused
.prev
);
588 dentry_stat
.nr_unused
++;
593 * We can return to the caller if we have found some (this
594 * ensures forward progress). We'll be coming back to find
597 if (found
&& need_resched())
601 * Descend a level if the d_subdirs list is non-empty.
603 if (!list_empty(&dentry
->d_subdirs
)) {
604 this_parent
= dentry
;
609 * All done at this level ... ascend and resume the search.
611 if (this_parent
!= parent
) {
612 next
= this_parent
->d_u
.d_child
.next
;
613 this_parent
= this_parent
->d_parent
;
617 spin_unlock(&dcache_lock
);
622 * shrink_dcache_parent - prune dcache
623 * @parent: parent of entries to prune
625 * Prune the dcache to remove unused children of the parent dentry.
628 void shrink_dcache_parent(struct dentry
* parent
)
632 while ((found
= select_parent(parent
)) != 0)
637 * shrink_dcache_anon - further prune the cache
638 * @head: head of d_hash list of dentries to prune
640 * Prune the dentries that are anonymous
642 * parsing d_hash list does not hlist_for_each_entry_rcu() as it
643 * done under dcache_lock.
646 void shrink_dcache_anon(struct hlist_head
*head
)
648 struct hlist_node
*lp
;
652 spin_lock(&dcache_lock
);
653 hlist_for_each(lp
, head
) {
654 struct dentry
*this = hlist_entry(lp
, struct dentry
, d_hash
);
655 if (!list_empty(&this->d_lru
)) {
656 dentry_stat
.nr_unused
--;
657 list_del_init(&this->d_lru
);
661 * move only zero ref count dentries to the end
662 * of the unused list for prune_dcache
664 if (!atomic_read(&this->d_count
)) {
665 list_add_tail(&this->d_lru
, &dentry_unused
);
666 dentry_stat
.nr_unused
++;
670 spin_unlock(&dcache_lock
);
676 * Scan `nr' dentries and return the number which remain.
678 * We need to avoid reentering the filesystem if the caller is performing a
679 * GFP_NOFS allocation attempt. One example deadlock is:
681 * ext2_new_block->getblk->GFP->shrink_dcache_memory->prune_dcache->
682 * prune_one_dentry->dput->dentry_iput->iput->inode->i_sb->s_op->put_inode->
683 * ext2_discard_prealloc->ext2_free_blocks->lock_super->DEADLOCK.
685 * In this case we return -1 to tell the caller that we baled.
687 static int shrink_dcache_memory(int nr
, gfp_t gfp_mask
)
690 if (!(gfp_mask
& __GFP_FS
))
694 return (dentry_stat
.nr_unused
/ 100) * sysctl_vfs_cache_pressure
;
698 * d_alloc - allocate a dcache entry
699 * @parent: parent of entry to allocate
700 * @name: qstr of the name
702 * Allocates a dentry. It returns %NULL if there is insufficient memory
703 * available. On a success the dentry is returned. The name passed in is
704 * copied and the copy passed in may be reused after this call.
707 struct dentry
*d_alloc(struct dentry
* parent
, const struct qstr
*name
)
709 struct dentry
*dentry
;
712 dentry
= kmem_cache_alloc(dentry_cache
, GFP_KERNEL
);
716 if (name
->len
> DNAME_INLINE_LEN
-1) {
717 dname
= kmalloc(name
->len
+ 1, GFP_KERNEL
);
719 kmem_cache_free(dentry_cache
, dentry
);
723 dname
= dentry
->d_iname
;
725 dentry
->d_name
.name
= dname
;
727 dentry
->d_name
.len
= name
->len
;
728 dentry
->d_name
.hash
= name
->hash
;
729 memcpy(dname
, name
->name
, name
->len
);
730 dname
[name
->len
] = 0;
732 atomic_set(&dentry
->d_count
, 1);
733 dentry
->d_flags
= DCACHE_UNHASHED
;
734 spin_lock_init(&dentry
->d_lock
);
735 dentry
->d_inode
= NULL
;
736 dentry
->d_parent
= NULL
;
739 dentry
->d_fsdata
= NULL
;
740 dentry
->d_mounted
= 0;
741 #ifdef CONFIG_PROFILING
742 dentry
->d_cookie
= NULL
;
744 INIT_HLIST_NODE(&dentry
->d_hash
);
745 INIT_LIST_HEAD(&dentry
->d_lru
);
746 INIT_LIST_HEAD(&dentry
->d_subdirs
);
747 INIT_LIST_HEAD(&dentry
->d_alias
);
750 dentry
->d_parent
= dget(parent
);
751 dentry
->d_sb
= parent
->d_sb
;
753 INIT_LIST_HEAD(&dentry
->d_u
.d_child
);
756 spin_lock(&dcache_lock
);
758 list_add(&dentry
->d_u
.d_child
, &parent
->d_subdirs
);
759 dentry_stat
.nr_dentry
++;
760 spin_unlock(&dcache_lock
);
765 struct dentry
*d_alloc_name(struct dentry
*parent
, const char *name
)
770 q
.len
= strlen(name
);
771 q
.hash
= full_name_hash(q
.name
, q
.len
);
772 return d_alloc(parent
, &q
);
776 * d_instantiate - fill in inode information for a dentry
777 * @entry: dentry to complete
778 * @inode: inode to attach to this dentry
780 * Fill in inode information in the entry.
782 * This turns negative dentries into productive full members
785 * NOTE! This assumes that the inode count has been incremented
786 * (or otherwise set) by the caller to indicate that it is now
787 * in use by the dcache.
790 void d_instantiate(struct dentry
*entry
, struct inode
* inode
)
792 BUG_ON(!list_empty(&entry
->d_alias
));
793 spin_lock(&dcache_lock
);
795 list_add(&entry
->d_alias
, &inode
->i_dentry
);
796 entry
->d_inode
= inode
;
797 fsnotify_d_instantiate(entry
, inode
);
798 spin_unlock(&dcache_lock
);
799 security_d_instantiate(entry
, inode
);
803 * d_instantiate_unique - instantiate a non-aliased dentry
804 * @entry: dentry to instantiate
805 * @inode: inode to attach to this dentry
807 * Fill in inode information in the entry. On success, it returns NULL.
808 * If an unhashed alias of "entry" already exists, then we return the
809 * aliased dentry instead and drop one reference to inode.
811 * Note that in order to avoid conflicts with rename() etc, the caller
812 * had better be holding the parent directory semaphore.
814 * This also assumes that the inode count has been incremented
815 * (or otherwise set) by the caller to indicate that it is now
816 * in use by the dcache.
818 struct dentry
*d_instantiate_unique(struct dentry
*entry
, struct inode
*inode
)
820 struct dentry
*alias
;
821 int len
= entry
->d_name
.len
;
822 const char *name
= entry
->d_name
.name
;
823 unsigned int hash
= entry
->d_name
.hash
;
825 BUG_ON(!list_empty(&entry
->d_alias
));
826 spin_lock(&dcache_lock
);
829 list_for_each_entry(alias
, &inode
->i_dentry
, d_alias
) {
830 struct qstr
*qstr
= &alias
->d_name
;
832 if (qstr
->hash
!= hash
)
834 if (alias
->d_parent
!= entry
->d_parent
)
836 if (qstr
->len
!= len
)
838 if (memcmp(qstr
->name
, name
, len
))
841 spin_unlock(&dcache_lock
);
842 BUG_ON(!d_unhashed(alias
));
846 list_add(&entry
->d_alias
, &inode
->i_dentry
);
848 entry
->d_inode
= inode
;
849 fsnotify_d_instantiate(entry
, inode
);
850 spin_unlock(&dcache_lock
);
851 security_d_instantiate(entry
, inode
);
854 EXPORT_SYMBOL(d_instantiate_unique
);
857 * d_alloc_root - allocate root dentry
858 * @root_inode: inode to allocate the root for
860 * Allocate a root ("/") dentry for the inode given. The inode is
861 * instantiated and returned. %NULL is returned if there is insufficient
862 * memory or the inode passed is %NULL.
865 struct dentry
* d_alloc_root(struct inode
* root_inode
)
867 struct dentry
*res
= NULL
;
870 static const struct qstr name
= { .name
= "/", .len
= 1 };
872 res
= d_alloc(NULL
, &name
);
874 res
->d_sb
= root_inode
->i_sb
;
876 d_instantiate(res
, root_inode
);
882 static inline struct hlist_head
*d_hash(struct dentry
*parent
,
885 hash
+= ((unsigned long) parent
^ GOLDEN_RATIO_PRIME
) / L1_CACHE_BYTES
;
886 hash
= hash
^ ((hash
^ GOLDEN_RATIO_PRIME
) >> D_HASHBITS
);
887 return dentry_hashtable
+ (hash
& D_HASHMASK
);
891 * d_alloc_anon - allocate an anonymous dentry
892 * @inode: inode to allocate the dentry for
894 * This is similar to d_alloc_root. It is used by filesystems when
895 * creating a dentry for a given inode, often in the process of
896 * mapping a filehandle to a dentry. The returned dentry may be
897 * anonymous, or may have a full name (if the inode was already
898 * in the cache). The file system may need to make further
899 * efforts to connect this dentry into the dcache properly.
901 * When called on a directory inode, we must ensure that
902 * the inode only ever has one dentry. If a dentry is
903 * found, that is returned instead of allocating a new one.
905 * On successful return, the reference to the inode has been transferred
906 * to the dentry. If %NULL is returned (indicating kmalloc failure),
907 * the reference on the inode has not been released.
910 struct dentry
* d_alloc_anon(struct inode
*inode
)
912 static const struct qstr anonstring
= { .name
= "" };
916 if ((res
= d_find_alias(inode
))) {
921 tmp
= d_alloc(NULL
, &anonstring
);
925 tmp
->d_parent
= tmp
; /* make sure dput doesn't croak */
927 spin_lock(&dcache_lock
);
928 res
= __d_find_alias(inode
, 0);
930 /* attach a disconnected dentry */
933 spin_lock(&res
->d_lock
);
934 res
->d_sb
= inode
->i_sb
;
936 res
->d_inode
= inode
;
937 res
->d_flags
|= DCACHE_DISCONNECTED
;
938 res
->d_flags
&= ~DCACHE_UNHASHED
;
939 list_add(&res
->d_alias
, &inode
->i_dentry
);
940 hlist_add_head(&res
->d_hash
, &inode
->i_sb
->s_anon
);
941 spin_unlock(&res
->d_lock
);
943 inode
= NULL
; /* don't drop reference */
945 spin_unlock(&dcache_lock
);
956 * d_splice_alias - splice a disconnected dentry into the tree if one exists
957 * @inode: the inode which may have a disconnected dentry
958 * @dentry: a negative dentry which we want to point to the inode.
960 * If inode is a directory and has a 'disconnected' dentry (i.e. IS_ROOT and
961 * DCACHE_DISCONNECTED), then d_move that in place of the given dentry
962 * and return it, else simply d_add the inode to the dentry and return NULL.
964 * This is needed in the lookup routine of any filesystem that is exportable
965 * (via knfsd) so that we can build dcache paths to directories effectively.
967 * If a dentry was found and moved, then it is returned. Otherwise NULL
968 * is returned. This matches the expected return value of ->lookup.
971 struct dentry
*d_splice_alias(struct inode
*inode
, struct dentry
*dentry
)
973 struct dentry
*new = NULL
;
976 spin_lock(&dcache_lock
);
977 new = __d_find_alias(inode
, 1);
979 BUG_ON(!(new->d_flags
& DCACHE_DISCONNECTED
));
980 fsnotify_d_instantiate(new, inode
);
981 spin_unlock(&dcache_lock
);
982 security_d_instantiate(new, inode
);
987 /* d_instantiate takes dcache_lock, so we do it by hand */
988 list_add(&dentry
->d_alias
, &inode
->i_dentry
);
989 dentry
->d_inode
= inode
;
990 fsnotify_d_instantiate(dentry
, inode
);
991 spin_unlock(&dcache_lock
);
992 security_d_instantiate(dentry
, inode
);
996 d_add(dentry
, inode
);
1002 * d_lookup - search for a dentry
1003 * @parent: parent dentry
1004 * @name: qstr of name we wish to find
1006 * Searches the children of the parent dentry for the name in question. If
1007 * the dentry is found its reference count is incremented and the dentry
1008 * is returned. The caller must use d_put to free the entry when it has
1009 * finished using it. %NULL is returned on failure.
1011 * __d_lookup is dcache_lock free. The hash list is protected using RCU.
1012 * Memory barriers are used while updating and doing lockless traversal.
1013 * To avoid races with d_move while rename is happening, d_lock is used.
1015 * Overflows in memcmp(), while d_move, are avoided by keeping the length
1016 * and name pointer in one structure pointed by d_qstr.
1018 * rcu_read_lock() and rcu_read_unlock() are used to disable preemption while
1019 * lookup is going on.
1021 * dentry_unused list is not updated even if lookup finds the required dentry
1022 * in there. It is updated in places such as prune_dcache, shrink_dcache_sb,
1023 * select_parent and __dget_locked. This laziness saves lookup from dcache_lock
1026 * d_lookup() is protected against the concurrent renames in some unrelated
1027 * directory using the seqlockt_t rename_lock.
1030 struct dentry
* d_lookup(struct dentry
* parent
, struct qstr
* name
)
1032 struct dentry
* dentry
= NULL
;
1036 seq
= read_seqbegin(&rename_lock
);
1037 dentry
= __d_lookup(parent
, name
);
1040 } while (read_seqretry(&rename_lock
, seq
));
1044 struct dentry
* __d_lookup(struct dentry
* parent
, struct qstr
* name
)
1046 unsigned int len
= name
->len
;
1047 unsigned int hash
= name
->hash
;
1048 const unsigned char *str
= name
->name
;
1049 struct hlist_head
*head
= d_hash(parent
,hash
);
1050 struct dentry
*found
= NULL
;
1051 struct hlist_node
*node
;
1052 struct dentry
*dentry
;
1056 hlist_for_each_entry_rcu(dentry
, node
, head
, d_hash
) {
1059 if (dentry
->d_name
.hash
!= hash
)
1061 if (dentry
->d_parent
!= parent
)
1064 spin_lock(&dentry
->d_lock
);
1067 * Recheck the dentry after taking the lock - d_move may have
1068 * changed things. Don't bother checking the hash because we're
1069 * about to compare the whole name anyway.
1071 if (dentry
->d_parent
!= parent
)
1075 * It is safe to compare names since d_move() cannot
1076 * change the qstr (protected by d_lock).
1078 qstr
= &dentry
->d_name
;
1079 if (parent
->d_op
&& parent
->d_op
->d_compare
) {
1080 if (parent
->d_op
->d_compare(parent
, qstr
, name
))
1083 if (qstr
->len
!= len
)
1085 if (memcmp(qstr
->name
, str
, len
))
1089 if (!d_unhashed(dentry
)) {
1090 atomic_inc(&dentry
->d_count
);
1093 spin_unlock(&dentry
->d_lock
);
1096 spin_unlock(&dentry
->d_lock
);
1104 * d_validate - verify dentry provided from insecure source
1105 * @dentry: The dentry alleged to be valid child of @dparent
1106 * @dparent: The parent dentry (known to be valid)
1107 * @hash: Hash of the dentry
1108 * @len: Length of the name
1110 * An insecure source has sent us a dentry, here we verify it and dget() it.
1111 * This is used by ncpfs in its readdir implementation.
1112 * Zero is returned in the dentry is invalid.
1115 int d_validate(struct dentry
*dentry
, struct dentry
*dparent
)
1117 struct hlist_head
*base
;
1118 struct hlist_node
*lhp
;
1120 /* Check whether the ptr might be valid at all.. */
1121 if (!kmem_ptr_validate(dentry_cache
, dentry
))
1124 if (dentry
->d_parent
!= dparent
)
1127 spin_lock(&dcache_lock
);
1128 base
= d_hash(dparent
, dentry
->d_name
.hash
);
1129 hlist_for_each(lhp
,base
) {
1130 /* hlist_for_each_entry_rcu() not required for d_hash list
1131 * as it is parsed under dcache_lock
1133 if (dentry
== hlist_entry(lhp
, struct dentry
, d_hash
)) {
1134 __dget_locked(dentry
);
1135 spin_unlock(&dcache_lock
);
1139 spin_unlock(&dcache_lock
);
1145 * When a file is deleted, we have two options:
1146 * - turn this dentry into a negative dentry
1147 * - unhash this dentry and free it.
1149 * Usually, we want to just turn this into
1150 * a negative dentry, but if anybody else is
1151 * currently using the dentry or the inode
1152 * we can't do that and we fall back on removing
1153 * it from the hash queues and waiting for
1154 * it to be deleted later when it has no users
1158 * d_delete - delete a dentry
1159 * @dentry: The dentry to delete
1161 * Turn the dentry into a negative dentry if possible, otherwise
1162 * remove it from the hash queues so it can be deleted later
1165 void d_delete(struct dentry
* dentry
)
1169 * Are we the only user?
1171 spin_lock(&dcache_lock
);
1172 spin_lock(&dentry
->d_lock
);
1173 isdir
= S_ISDIR(dentry
->d_inode
->i_mode
);
1174 if (atomic_read(&dentry
->d_count
) == 1) {
1175 /* remove this and other inotify debug checks after 2.6.18 */
1176 dentry
->d_flags
&= ~DCACHE_INOTIFY_PARENT_WATCHED
;
1178 dentry_iput(dentry
);
1179 fsnotify_nameremove(dentry
, isdir
);
1183 if (!d_unhashed(dentry
))
1186 spin_unlock(&dentry
->d_lock
);
1187 spin_unlock(&dcache_lock
);
1189 fsnotify_nameremove(dentry
, isdir
);
1192 static void __d_rehash(struct dentry
* entry
, struct hlist_head
*list
)
1195 entry
->d_flags
&= ~DCACHE_UNHASHED
;
1196 hlist_add_head_rcu(&entry
->d_hash
, list
);
1200 * d_rehash - add an entry back to the hash
1201 * @entry: dentry to add to the hash
1203 * Adds a dentry to the hash according to its name.
1206 void d_rehash(struct dentry
* entry
)
1208 struct hlist_head
*list
= d_hash(entry
->d_parent
, entry
->d_name
.hash
);
1210 spin_lock(&dcache_lock
);
1211 spin_lock(&entry
->d_lock
);
1212 __d_rehash(entry
, list
);
1213 spin_unlock(&entry
->d_lock
);
1214 spin_unlock(&dcache_lock
);
1217 #define do_switch(x,y) do { \
1218 __typeof__ (x) __tmp = x; \
1219 x = y; y = __tmp; } while (0)
1222 * When switching names, the actual string doesn't strictly have to
1223 * be preserved in the target - because we're dropping the target
1224 * anyway. As such, we can just do a simple memcpy() to copy over
1225 * the new name before we switch.
1227 * Note that we have to be a lot more careful about getting the hash
1228 * switched - we have to switch the hash value properly even if it
1229 * then no longer matches the actual (corrupted) string of the target.
1230 * The hash value has to match the hash queue that the dentry is on..
1232 static void switch_names(struct dentry
*dentry
, struct dentry
*target
)
1234 if (dname_external(target
)) {
1235 if (dname_external(dentry
)) {
1237 * Both external: swap the pointers
1239 do_switch(target
->d_name
.name
, dentry
->d_name
.name
);
1242 * dentry:internal, target:external. Steal target's
1243 * storage and make target internal.
1245 dentry
->d_name
.name
= target
->d_name
.name
;
1246 target
->d_name
.name
= target
->d_iname
;
1249 if (dname_external(dentry
)) {
1251 * dentry:external, target:internal. Give dentry's
1252 * storage to target and make dentry internal
1254 memcpy(dentry
->d_iname
, target
->d_name
.name
,
1255 target
->d_name
.len
+ 1);
1256 target
->d_name
.name
= dentry
->d_name
.name
;
1257 dentry
->d_name
.name
= dentry
->d_iname
;
1260 * Both are internal. Just copy target to dentry
1262 memcpy(dentry
->d_iname
, target
->d_name
.name
,
1263 target
->d_name
.len
+ 1);
1269 * We cannibalize "target" when moving dentry on top of it,
1270 * because it's going to be thrown away anyway. We could be more
1271 * polite about it, though.
1273 * This forceful removal will result in ugly /proc output if
1274 * somebody holds a file open that got deleted due to a rename.
1275 * We could be nicer about the deleted file, and let it show
1276 * up under the name it got deleted rather than the name that
1281 * d_move - move a dentry
1282 * @dentry: entry to move
1283 * @target: new dentry
1285 * Update the dcache to reflect the move of a file name. Negative
1286 * dcache entries should not be moved in this way.
1289 void d_move(struct dentry
* dentry
, struct dentry
* target
)
1291 struct hlist_head
*list
;
1293 if (!dentry
->d_inode
)
1294 printk(KERN_WARNING
"VFS: moving negative dcache entry\n");
1296 spin_lock(&dcache_lock
);
1297 write_seqlock(&rename_lock
);
1299 * XXXX: do we really need to take target->d_lock?
1301 if (target
< dentry
) {
1302 spin_lock(&target
->d_lock
);
1303 spin_lock(&dentry
->d_lock
);
1305 spin_lock(&dentry
->d_lock
);
1306 spin_lock(&target
->d_lock
);
1309 /* Move the dentry to the target hash queue, if on different bucket */
1310 if (dentry
->d_flags
& DCACHE_UNHASHED
)
1311 goto already_unhashed
;
1313 hlist_del_rcu(&dentry
->d_hash
);
1316 list
= d_hash(target
->d_parent
, target
->d_name
.hash
);
1317 __d_rehash(dentry
, list
);
1319 /* Unhash the target: dput() will then get rid of it */
1322 list_del(&dentry
->d_u
.d_child
);
1323 list_del(&target
->d_u
.d_child
);
1325 /* Switch the names.. */
1326 switch_names(dentry
, target
);
1327 do_switch(dentry
->d_name
.len
, target
->d_name
.len
);
1328 do_switch(dentry
->d_name
.hash
, target
->d_name
.hash
);
1330 /* ... and switch the parents */
1331 if (IS_ROOT(dentry
)) {
1332 dentry
->d_parent
= target
->d_parent
;
1333 target
->d_parent
= target
;
1334 INIT_LIST_HEAD(&target
->d_u
.d_child
);
1336 do_switch(dentry
->d_parent
, target
->d_parent
);
1338 /* And add them back to the (new) parent lists */
1339 list_add(&target
->d_u
.d_child
, &target
->d_parent
->d_subdirs
);
1342 list_add(&dentry
->d_u
.d_child
, &dentry
->d_parent
->d_subdirs
);
1343 spin_unlock(&target
->d_lock
);
1344 fsnotify_d_move(dentry
);
1345 spin_unlock(&dentry
->d_lock
);
1346 write_sequnlock(&rename_lock
);
1347 spin_unlock(&dcache_lock
);
1351 * d_path - return the path of a dentry
1352 * @dentry: dentry to report
1353 * @vfsmnt: vfsmnt to which the dentry belongs
1354 * @root: root dentry
1355 * @rootmnt: vfsmnt to which the root dentry belongs
1356 * @buffer: buffer to return value in
1357 * @buflen: buffer length
1359 * Convert a dentry into an ASCII path name. If the entry has been deleted
1360 * the string " (deleted)" is appended. Note that this is ambiguous.
1362 * Returns the buffer or an error code if the path was too long.
1364 * "buflen" should be positive. Caller holds the dcache_lock.
1366 static char * __d_path( struct dentry
*dentry
, struct vfsmount
*vfsmnt
,
1367 struct dentry
*root
, struct vfsmount
*rootmnt
,
1368 char *buffer
, int buflen
)
1370 char * end
= buffer
+buflen
;
1376 if (!IS_ROOT(dentry
) && d_unhashed(dentry
)) {
1381 memcpy(end
, " (deleted)", 10);
1391 struct dentry
* parent
;
1393 if (dentry
== root
&& vfsmnt
== rootmnt
)
1395 if (dentry
== vfsmnt
->mnt_root
|| IS_ROOT(dentry
)) {
1397 spin_lock(&vfsmount_lock
);
1398 if (vfsmnt
->mnt_parent
== vfsmnt
) {
1399 spin_unlock(&vfsmount_lock
);
1402 dentry
= vfsmnt
->mnt_mountpoint
;
1403 vfsmnt
= vfsmnt
->mnt_parent
;
1404 spin_unlock(&vfsmount_lock
);
1407 parent
= dentry
->d_parent
;
1409 namelen
= dentry
->d_name
.len
;
1410 buflen
-= namelen
+ 1;
1414 memcpy(end
, dentry
->d_name
.name
, namelen
);
1423 namelen
= dentry
->d_name
.len
;
1427 retval
-= namelen
-1; /* hit the slash */
1428 memcpy(retval
, dentry
->d_name
.name
, namelen
);
1431 return ERR_PTR(-ENAMETOOLONG
);
1434 /* write full pathname into buffer and return start of pathname */
1435 char * d_path(struct dentry
*dentry
, struct vfsmount
*vfsmnt
,
1436 char *buf
, int buflen
)
1439 struct vfsmount
*rootmnt
;
1440 struct dentry
*root
;
1442 read_lock(¤t
->fs
->lock
);
1443 rootmnt
= mntget(current
->fs
->rootmnt
);
1444 root
= dget(current
->fs
->root
);
1445 read_unlock(¤t
->fs
->lock
);
1446 spin_lock(&dcache_lock
);
1447 res
= __d_path(dentry
, vfsmnt
, root
, rootmnt
, buf
, buflen
);
1448 spin_unlock(&dcache_lock
);
1455 * NOTE! The user-level library version returns a
1456 * character pointer. The kernel system call just
1457 * returns the length of the buffer filled (which
1458 * includes the ending '\0' character), or a negative
1459 * error value. So libc would do something like
1461 * char *getcwd(char * buf, size_t size)
1465 * retval = sys_getcwd(buf, size);
1472 asmlinkage
long sys_getcwd(char __user
*buf
, unsigned long size
)
1475 struct vfsmount
*pwdmnt
, *rootmnt
;
1476 struct dentry
*pwd
, *root
;
1477 char *page
= (char *) __get_free_page(GFP_USER
);
1482 read_lock(¤t
->fs
->lock
);
1483 pwdmnt
= mntget(current
->fs
->pwdmnt
);
1484 pwd
= dget(current
->fs
->pwd
);
1485 rootmnt
= mntget(current
->fs
->rootmnt
);
1486 root
= dget(current
->fs
->root
);
1487 read_unlock(¤t
->fs
->lock
);
1490 /* Has the current directory has been unlinked? */
1491 spin_lock(&dcache_lock
);
1492 if (pwd
->d_parent
== pwd
|| !d_unhashed(pwd
)) {
1496 cwd
= __d_path(pwd
, pwdmnt
, root
, rootmnt
, page
, PAGE_SIZE
);
1497 spin_unlock(&dcache_lock
);
1499 error
= PTR_ERR(cwd
);
1504 len
= PAGE_SIZE
+ page
- cwd
;
1507 if (copy_to_user(buf
, cwd
, len
))
1511 spin_unlock(&dcache_lock
);
1518 free_page((unsigned long) page
);
1523 * Test whether new_dentry is a subdirectory of old_dentry.
1525 * Trivially implemented using the dcache structure
1529 * is_subdir - is new dentry a subdirectory of old_dentry
1530 * @new_dentry: new dentry
1531 * @old_dentry: old dentry
1533 * Returns 1 if new_dentry is a subdirectory of the parent (at any depth).
1534 * Returns 0 otherwise.
1535 * Caller must ensure that "new_dentry" is pinned before calling is_subdir()
1538 int is_subdir(struct dentry
* new_dentry
, struct dentry
* old_dentry
)
1541 struct dentry
* saved
= new_dentry
;
1544 /* need rcu_readlock to protect against the d_parent trashing due to
1549 /* for restarting inner loop in case of seq retry */
1552 seq
= read_seqbegin(&rename_lock
);
1554 if (new_dentry
!= old_dentry
) {
1555 struct dentry
* parent
= new_dentry
->d_parent
;
1556 if (parent
== new_dentry
)
1558 new_dentry
= parent
;
1564 } while (read_seqretry(&rename_lock
, seq
));
1570 void d_genocide(struct dentry
*root
)
1572 struct dentry
*this_parent
= root
;
1573 struct list_head
*next
;
1575 spin_lock(&dcache_lock
);
1577 next
= this_parent
->d_subdirs
.next
;
1579 while (next
!= &this_parent
->d_subdirs
) {
1580 struct list_head
*tmp
= next
;
1581 struct dentry
*dentry
= list_entry(tmp
, struct dentry
, d_u
.d_child
);
1583 if (d_unhashed(dentry
)||!dentry
->d_inode
)
1585 if (!list_empty(&dentry
->d_subdirs
)) {
1586 this_parent
= dentry
;
1589 atomic_dec(&dentry
->d_count
);
1591 if (this_parent
!= root
) {
1592 next
= this_parent
->d_u
.d_child
.next
;
1593 atomic_dec(&this_parent
->d_count
);
1594 this_parent
= this_parent
->d_parent
;
1597 spin_unlock(&dcache_lock
);
1601 * find_inode_number - check for dentry with name
1602 * @dir: directory to check
1603 * @name: Name to find.
1605 * Check whether a dentry already exists for the given name,
1606 * and return the inode number if it has an inode. Otherwise
1609 * This routine is used to post-process directory listings for
1610 * filesystems using synthetic inode numbers, and is necessary
1611 * to keep getcwd() working.
1614 ino_t
find_inode_number(struct dentry
*dir
, struct qstr
*name
)
1616 struct dentry
* dentry
;
1620 * Check for a fs-specific hash function. Note that we must
1621 * calculate the standard hash first, as the d_op->d_hash()
1622 * routine may choose to leave the hash value unchanged.
1624 name
->hash
= full_name_hash(name
->name
, name
->len
);
1625 if (dir
->d_op
&& dir
->d_op
->d_hash
)
1627 if (dir
->d_op
->d_hash(dir
, name
) != 0)
1631 dentry
= d_lookup(dir
, name
);
1634 if (dentry
->d_inode
)
1635 ino
= dentry
->d_inode
->i_ino
;
1642 static __initdata
unsigned long dhash_entries
;
1643 static int __init
set_dhash_entries(char *str
)
1647 dhash_entries
= simple_strtoul(str
, &str
, 0);
1650 __setup("dhash_entries=", set_dhash_entries
);
1652 static void __init
dcache_init_early(void)
1656 /* If hashes are distributed across NUMA nodes, defer
1657 * hash allocation until vmalloc space is available.
1663 alloc_large_system_hash("Dentry cache",
1664 sizeof(struct hlist_head
),
1672 for (loop
= 0; loop
< (1 << d_hash_shift
); loop
++)
1673 INIT_HLIST_HEAD(&dentry_hashtable
[loop
]);
1676 static void __init
dcache_init(unsigned long mempages
)
1681 * A constructor could be added for stable state like the lists,
1682 * but it is probably not worth it because of the cache nature
1685 dentry_cache
= kmem_cache_create("dentry_cache",
1686 sizeof(struct dentry
),
1688 (SLAB_RECLAIM_ACCOUNT
|SLAB_PANIC
|
1692 set_shrinker(DEFAULT_SEEKS
, shrink_dcache_memory
);
1694 /* Hash may have been set up in dcache_init_early */
1699 alloc_large_system_hash("Dentry cache",
1700 sizeof(struct hlist_head
),
1708 for (loop
= 0; loop
< (1 << d_hash_shift
); loop
++)
1709 INIT_HLIST_HEAD(&dentry_hashtable
[loop
]);
1712 /* SLAB cache for __getname() consumers */
1713 kmem_cache_t
*names_cachep __read_mostly
;
1715 /* SLAB cache for file structures */
1716 kmem_cache_t
*filp_cachep __read_mostly
;
1718 EXPORT_SYMBOL(d_genocide
);
1720 extern void bdev_cache_init(void);
1721 extern void chrdev_init(void);
1723 void __init
vfs_caches_init_early(void)
1725 dcache_init_early();
1729 void __init
vfs_caches_init(unsigned long mempages
)
1731 unsigned long reserve
;
1733 /* Base hash sizes on available memory, with a reserve equal to
1734 150% of current kernel size */
1736 reserve
= min((mempages
- nr_free_pages()) * 3/2, mempages
- 1);
1737 mempages
-= reserve
;
1739 names_cachep
= kmem_cache_create("names_cache", PATH_MAX
, 0,
1740 SLAB_HWCACHE_ALIGN
|SLAB_PANIC
, NULL
, NULL
);
1742 filp_cachep
= kmem_cache_create("filp", sizeof(struct file
), 0,
1743 SLAB_HWCACHE_ALIGN
|SLAB_PANIC
, NULL
, NULL
);
1745 dcache_init(mempages
);
1746 inode_init(mempages
);
1747 files_init(mempages
);
1753 EXPORT_SYMBOL(d_alloc
);
1754 EXPORT_SYMBOL(d_alloc_anon
);
1755 EXPORT_SYMBOL(d_alloc_root
);
1756 EXPORT_SYMBOL(d_delete
);
1757 EXPORT_SYMBOL(d_find_alias
);
1758 EXPORT_SYMBOL(d_instantiate
);
1759 EXPORT_SYMBOL(d_invalidate
);
1760 EXPORT_SYMBOL(d_lookup
);
1761 EXPORT_SYMBOL(d_move
);
1762 EXPORT_SYMBOL(d_path
);
1763 EXPORT_SYMBOL(d_prune_aliases
);
1764 EXPORT_SYMBOL(d_rehash
);
1765 EXPORT_SYMBOL(d_splice_alias
);
1766 EXPORT_SYMBOL(d_validate
);
1767 EXPORT_SYMBOL(dget_locked
);
1768 EXPORT_SYMBOL(dput
);
1769 EXPORT_SYMBOL(find_inode_number
);
1770 EXPORT_SYMBOL(have_submounts
);
1771 EXPORT_SYMBOL(names_cachep
);
1772 EXPORT_SYMBOL(shrink_dcache_parent
);
1773 EXPORT_SYMBOL(shrink_dcache_sb
);