2 * fs/kernfs/dir.c - kernfs directory implementation
4 * Copyright (c) 2001-3 Patrick Mochel
5 * Copyright (c) 2007 SUSE Linux Products GmbH
6 * Copyright (c) 2007, 2013 Tejun Heo <tj@kernel.org>
8 * This file is released under the GPLv2.
12 #include <linux/namei.h>
13 #include <linux/idr.h>
14 #include <linux/slab.h>
15 #include <linux/security.h>
16 #include <linux/hash.h>
18 #include "kernfs-internal.h"
20 DEFINE_MUTEX(kernfs_mutex
);
22 #define rb_to_kn(X) rb_entry((X), struct kernfs_node, rb)
26 * @name: Null terminated string to hash
27 * @ns: Namespace tag to hash
29 * Returns 31 bit hash of ns + name (so it fits in an off_t )
31 static unsigned int kernfs_name_hash(const char *name
, const void *ns
)
33 unsigned long hash
= init_name_hash();
34 unsigned int len
= strlen(name
);
36 hash
= partial_name_hash(*name
++, hash
);
37 hash
= (end_name_hash(hash
) ^ hash_ptr((void *)ns
, 31));
39 /* Reserve hash numbers 0, 1 and INT_MAX for magic directory entries */
47 static int kernfs_name_compare(unsigned int hash
, const char *name
,
48 const void *ns
, const struct kernfs_node
*kn
)
51 return hash
- kn
->hash
;
54 return strcmp(name
, kn
->name
);
57 static int kernfs_sd_compare(const struct kernfs_node
*left
,
58 const struct kernfs_node
*right
)
60 return kernfs_name_compare(left
->hash
, left
->name
, left
->ns
, right
);
64 * kernfs_link_sibling - link kernfs_node into sibling rbtree
65 * @kn: kernfs_node of interest
67 * Link @kn into its sibling rbtree which starts from
68 * @kn->parent->dir.children.
71 * mutex_lock(kernfs_mutex)
74 * 0 on susccess -EEXIST on failure.
76 static int kernfs_link_sibling(struct kernfs_node
*kn
)
78 struct rb_node
**node
= &kn
->parent
->dir
.children
.rb_node
;
79 struct rb_node
*parent
= NULL
;
81 if (kernfs_type(kn
) == KERNFS_DIR
)
82 kn
->parent
->dir
.subdirs
++;
85 struct kernfs_node
*pos
;
88 pos
= rb_to_kn(*node
);
90 result
= kernfs_sd_compare(kn
, pos
);
92 node
= &pos
->rb
.rb_left
;
94 node
= &pos
->rb
.rb_right
;
98 /* add new node and rebalance the tree */
99 rb_link_node(&kn
->rb
, parent
, node
);
100 rb_insert_color(&kn
->rb
, &kn
->parent
->dir
.children
);
105 * kernfs_unlink_sibling - unlink kernfs_node from sibling rbtree
106 * @kn: kernfs_node of interest
108 * Unlink @kn from its sibling rbtree which starts from
109 * kn->parent->dir.children.
112 * mutex_lock(kernfs_mutex)
114 static void kernfs_unlink_sibling(struct kernfs_node
*kn
)
116 if (kernfs_type(kn
) == KERNFS_DIR
)
117 kn
->parent
->dir
.subdirs
--;
119 rb_erase(&kn
->rb
, &kn
->parent
->dir
.children
);
123 * kernfs_get_active - get an active reference to kernfs_node
124 * @kn: kernfs_node to get an active reference to
126 * Get an active reference of @kn. This function is noop if @kn
130 * Pointer to @kn on success, NULL on failure.
132 struct kernfs_node
*kernfs_get_active(struct kernfs_node
*kn
)
137 if (!atomic_inc_unless_negative(&kn
->active
))
140 if (kn
->flags
& KERNFS_LOCKDEP
)
141 rwsem_acquire_read(&kn
->dep_map
, 0, 1, _RET_IP_
);
146 * kernfs_put_active - put an active reference to kernfs_node
147 * @kn: kernfs_node to put an active reference to
149 * Put an active reference to @kn. This function is noop if @kn
152 void kernfs_put_active(struct kernfs_node
*kn
)
159 if (kn
->flags
& KERNFS_LOCKDEP
)
160 rwsem_release(&kn
->dep_map
, 1, _RET_IP_
);
161 v
= atomic_dec_return(&kn
->active
);
162 if (likely(v
!= KN_DEACTIVATED_BIAS
))
166 * atomic_dec_return() is a mb(), we'll always see the updated
169 complete(kn
->u
.completion
);
173 * kernfs_deactivate - deactivate kernfs_node
174 * @kn: kernfs_node to deactivate
176 * Deny new active references and drain existing ones.
178 static void kernfs_deactivate(struct kernfs_node
*kn
)
180 DECLARE_COMPLETION_ONSTACK(wait
);
183 BUG_ON(!(kn
->flags
& KERNFS_REMOVED
));
185 if (!(kernfs_type(kn
) & KERNFS_ACTIVE_REF
))
188 kn
->u
.completion
= (void *)&wait
;
190 rwsem_acquire(&kn
->dep_map
, 0, 0, _RET_IP_
);
191 /* atomic_add_return() is a mb(), put_active() will always see
192 * the updated kn->u.completion.
194 v
= atomic_add_return(KN_DEACTIVATED_BIAS
, &kn
->active
);
196 if (v
!= KN_DEACTIVATED_BIAS
) {
197 lock_contended(&kn
->dep_map
, _RET_IP_
);
198 wait_for_completion(&wait
);
201 lock_acquired(&kn
->dep_map
, _RET_IP_
);
202 rwsem_release(&kn
->dep_map
, 1, _RET_IP_
);
206 * kernfs_get - get a reference count on a kernfs_node
207 * @kn: the target kernfs_node
209 void kernfs_get(struct kernfs_node
*kn
)
212 WARN_ON(!atomic_read(&kn
->count
));
213 atomic_inc(&kn
->count
);
216 EXPORT_SYMBOL_GPL(kernfs_get
);
219 * kernfs_put - put a reference count on a kernfs_node
220 * @kn: the target kernfs_node
222 * Put a reference count of @kn and destroy it if it reached zero.
224 void kernfs_put(struct kernfs_node
*kn
)
226 struct kernfs_node
*parent
;
227 struct kernfs_root
*root
;
229 if (!kn
|| !atomic_dec_and_test(&kn
->count
))
231 root
= kernfs_root(kn
);
233 /* Moving/renaming is always done while holding reference.
234 * kn->parent won't change beneath us.
238 WARN(!(kn
->flags
& KERNFS_REMOVED
), "kernfs: free using entry: %s/%s\n",
239 parent
? parent
->name
: "", kn
->name
);
241 if (kernfs_type(kn
) == KERNFS_LINK
)
242 kernfs_put(kn
->symlink
.target_kn
);
243 if (!(kn
->flags
& KERNFS_STATIC_NAME
))
246 if (kn
->iattr
->ia_secdata
)
247 security_release_secctx(kn
->iattr
->ia_secdata
,
248 kn
->iattr
->ia_secdata_len
);
249 simple_xattrs_free(&kn
->iattr
->xattrs
);
252 ida_simple_remove(&root
->ino_ida
, kn
->ino
);
253 kmem_cache_free(kernfs_node_cache
, kn
);
257 if (atomic_dec_and_test(&kn
->count
))
260 /* just released the root kn, free @root too */
261 ida_destroy(&root
->ino_ida
);
265 EXPORT_SYMBOL_GPL(kernfs_put
);
267 static int kernfs_dop_revalidate(struct dentry
*dentry
, unsigned int flags
)
269 struct kernfs_node
*kn
;
271 if (flags
& LOOKUP_RCU
)
274 /* Always perform fresh lookup for negatives */
275 if (!dentry
->d_inode
)
276 goto out_bad_unlocked
;
278 kn
= dentry
->d_fsdata
;
279 mutex_lock(&kernfs_mutex
);
281 /* The kernfs node has been deleted */
282 if (kn
->flags
& KERNFS_REMOVED
)
285 /* The kernfs node has been moved? */
286 if (dentry
->d_parent
->d_fsdata
!= kn
->parent
)
289 /* The kernfs node has been renamed */
290 if (strcmp(dentry
->d_name
.name
, kn
->name
) != 0)
293 /* The kernfs node has been moved to a different namespace */
294 if (kn
->parent
&& kernfs_ns_enabled(kn
->parent
) &&
295 kernfs_info(dentry
->d_sb
)->ns
!= kn
->ns
)
298 mutex_unlock(&kernfs_mutex
);
302 mutex_unlock(&kernfs_mutex
);
305 * @dentry doesn't match the underlying kernfs node, drop the
306 * dentry and force lookup. If we have submounts we must allow the
307 * vfs caches to lie about the state of the filesystem to prevent
308 * leaks and other nasty things, so use check_submounts_and_drop()
309 * instead of d_drop().
311 if (check_submounts_and_drop(dentry
) != 0)
317 static void kernfs_dop_release(struct dentry
*dentry
)
319 kernfs_put(dentry
->d_fsdata
);
322 const struct dentry_operations kernfs_dops
= {
323 .d_revalidate
= kernfs_dop_revalidate
,
324 .d_release
= kernfs_dop_release
,
327 static struct kernfs_node
*__kernfs_new_node(struct kernfs_root
*root
,
328 const char *name
, umode_t mode
,
331 char *dup_name
= NULL
;
332 struct kernfs_node
*kn
;
335 if (!(flags
& KERNFS_STATIC_NAME
)) {
336 name
= dup_name
= kstrdup(name
, GFP_KERNEL
);
341 kn
= kmem_cache_zalloc(kernfs_node_cache
, GFP_KERNEL
);
345 ret
= ida_simple_get(&root
->ino_ida
, 1, 0, GFP_KERNEL
);
350 atomic_set(&kn
->count
, 1);
351 atomic_set(&kn
->active
, 0);
355 kn
->flags
= flags
| KERNFS_REMOVED
;
360 kmem_cache_free(kernfs_node_cache
, kn
);
366 struct kernfs_node
*kernfs_new_node(struct kernfs_node
*parent
,
367 const char *name
, umode_t mode
,
370 struct kernfs_node
*kn
;
372 kn
= __kernfs_new_node(kernfs_root(parent
), name
, mode
, flags
);
381 * kernfs_addrm_start - prepare for kernfs_node add/remove
382 * @acxt: pointer to kernfs_addrm_cxt to be used
384 * This function is called when the caller is about to add or remove
385 * kernfs_node. This function acquires kernfs_mutex. @acxt is used
386 * to keep and pass context to other addrm functions.
389 * Kernel thread context (may sleep). kernfs_mutex is locked on
392 void kernfs_addrm_start(struct kernfs_addrm_cxt
*acxt
)
393 __acquires(kernfs_mutex
)
395 memset(acxt
, 0, sizeof(*acxt
));
397 mutex_lock(&kernfs_mutex
);
401 * kernfs_add_one - add kernfs_node to parent without warning
402 * @acxt: addrm context to use
403 * @kn: kernfs_node to be added
405 * The caller must already have initialized @kn->parent. This
406 * function increments nlink of the parent's inode if @kn is a
407 * directory and link into the children list of the parent.
409 * This function should be called between calls to
410 * kernfs_addrm_start() and kernfs_addrm_finish() and should be passed
411 * the same @acxt as passed to kernfs_addrm_start().
414 * Determined by kernfs_addrm_start().
417 * 0 on success, -EEXIST if entry with the given name already
420 int kernfs_add_one(struct kernfs_addrm_cxt
*acxt
, struct kernfs_node
*kn
)
422 struct kernfs_node
*parent
= kn
->parent
;
423 bool has_ns
= kernfs_ns_enabled(parent
);
424 struct kernfs_iattrs
*ps_iattr
;
427 if (has_ns
!= (bool)kn
->ns
) {
428 WARN(1, KERN_WARNING
"kernfs: ns %s in '%s' for '%s'\n",
429 has_ns
? "required" : "invalid", parent
->name
, kn
->name
);
433 if (kernfs_type(parent
) != KERNFS_DIR
)
436 if (parent
->flags
& KERNFS_REMOVED
)
439 kn
->hash
= kernfs_name_hash(kn
->name
, kn
->ns
);
441 ret
= kernfs_link_sibling(kn
);
445 /* Update timestamps on the parent */
446 ps_iattr
= parent
->iattr
;
448 struct iattr
*ps_iattrs
= &ps_iattr
->ia_iattr
;
449 ps_iattrs
->ia_ctime
= ps_iattrs
->ia_mtime
= CURRENT_TIME
;
452 /* Mark the entry added into directory tree */
453 kn
->flags
&= ~KERNFS_REMOVED
;
459 * kernfs_remove_one - remove kernfs_node from parent
460 * @acxt: addrm context to use
461 * @kn: kernfs_node to be removed
463 * Mark @kn removed and drop nlink of parent inode if @kn is a
464 * directory. @kn is unlinked from the children list.
466 * This function should be called between calls to
467 * kernfs_addrm_start() and kernfs_addrm_finish() and should be
468 * passed the same @acxt as passed to kernfs_addrm_start().
471 * Determined by kernfs_addrm_start().
473 static void kernfs_remove_one(struct kernfs_addrm_cxt
*acxt
,
474 struct kernfs_node
*kn
)
476 struct kernfs_iattrs
*ps_iattr
;
479 * Removal can be called multiple times on the same node. Only the
480 * first invocation is effective and puts the base ref.
482 if (kn
->flags
& KERNFS_REMOVED
)
486 kernfs_unlink_sibling(kn
);
488 /* Update timestamps on the parent */
489 ps_iattr
= kn
->parent
->iattr
;
491 ps_iattr
->ia_iattr
.ia_ctime
= CURRENT_TIME
;
492 ps_iattr
->ia_iattr
.ia_mtime
= CURRENT_TIME
;
496 kn
->flags
|= KERNFS_REMOVED
;
497 kn
->u
.removed_list
= acxt
->removed
;
502 * kernfs_addrm_finish - finish up kernfs_node add/remove
503 * @acxt: addrm context to finish up
505 * Finish up kernfs_node add/remove. Resources acquired by
506 * kernfs_addrm_start() are released and removed kernfs_nodes are
510 * kernfs_mutex is released.
512 void kernfs_addrm_finish(struct kernfs_addrm_cxt
*acxt
)
513 __releases(kernfs_mutex
)
515 /* release resources acquired by kernfs_addrm_start() */
516 mutex_unlock(&kernfs_mutex
);
518 /* kill removed kernfs_nodes */
519 while (acxt
->removed
) {
520 struct kernfs_node
*kn
= acxt
->removed
;
522 acxt
->removed
= kn
->u
.removed_list
;
524 kernfs_deactivate(kn
);
525 kernfs_unmap_bin_file(kn
);
531 * kernfs_find_ns - find kernfs_node with the given name
532 * @parent: kernfs_node to search under
533 * @name: name to look for
534 * @ns: the namespace tag to use
536 * Look for kernfs_node with name @name under @parent. Returns pointer to
537 * the found kernfs_node on success, %NULL on failure.
539 static struct kernfs_node
*kernfs_find_ns(struct kernfs_node
*parent
,
540 const unsigned char *name
,
543 struct rb_node
*node
= parent
->dir
.children
.rb_node
;
544 bool has_ns
= kernfs_ns_enabled(parent
);
547 lockdep_assert_held(&kernfs_mutex
);
549 if (has_ns
!= (bool)ns
) {
550 WARN(1, KERN_WARNING
"kernfs: ns %s in '%s' for '%s'\n",
551 has_ns
? "required" : "invalid", parent
->name
, name
);
555 hash
= kernfs_name_hash(name
, ns
);
557 struct kernfs_node
*kn
;
561 result
= kernfs_name_compare(hash
, name
, ns
, kn
);
563 node
= node
->rb_left
;
565 node
= node
->rb_right
;
573 * kernfs_find_and_get_ns - find and get kernfs_node with the given name
574 * @parent: kernfs_node to search under
575 * @name: name to look for
576 * @ns: the namespace tag to use
578 * Look for kernfs_node with name @name under @parent and get a reference
579 * if found. This function may sleep and returns pointer to the found
580 * kernfs_node on success, %NULL on failure.
582 struct kernfs_node
*kernfs_find_and_get_ns(struct kernfs_node
*parent
,
583 const char *name
, const void *ns
)
585 struct kernfs_node
*kn
;
587 mutex_lock(&kernfs_mutex
);
588 kn
= kernfs_find_ns(parent
, name
, ns
);
590 mutex_unlock(&kernfs_mutex
);
594 EXPORT_SYMBOL_GPL(kernfs_find_and_get_ns
);
597 * kernfs_create_root - create a new kernfs hierarchy
598 * @kdops: optional directory syscall operations for the hierarchy
599 * @priv: opaque data associated with the new directory
601 * Returns the root of the new hierarchy on success, ERR_PTR() value on
604 struct kernfs_root
*kernfs_create_root(struct kernfs_dir_ops
*kdops
, void *priv
)
606 struct kernfs_root
*root
;
607 struct kernfs_node
*kn
;
609 root
= kzalloc(sizeof(*root
), GFP_KERNEL
);
611 return ERR_PTR(-ENOMEM
);
613 ida_init(&root
->ino_ida
);
615 kn
= __kernfs_new_node(root
, "", S_IFDIR
| S_IRUGO
| S_IXUGO
,
618 ida_destroy(&root
->ino_ida
);
620 return ERR_PTR(-ENOMEM
);
623 kn
->flags
&= ~KERNFS_REMOVED
;
627 root
->dir_ops
= kdops
;
634 * kernfs_destroy_root - destroy a kernfs hierarchy
635 * @root: root of the hierarchy to destroy
637 * Destroy the hierarchy anchored at @root by removing all existing
638 * directories and destroying @root.
640 void kernfs_destroy_root(struct kernfs_root
*root
)
642 kernfs_remove(root
->kn
); /* will also free @root */
646 * kernfs_create_dir_ns - create a directory
647 * @parent: parent in which to create a new directory
648 * @name: name of the new directory
649 * @mode: mode of the new directory
650 * @priv: opaque data associated with the new directory
651 * @ns: optional namespace tag of the directory
653 * Returns the created node on success, ERR_PTR() value on failure.
655 struct kernfs_node
*kernfs_create_dir_ns(struct kernfs_node
*parent
,
656 const char *name
, umode_t mode
,
657 void *priv
, const void *ns
)
659 struct kernfs_addrm_cxt acxt
;
660 struct kernfs_node
*kn
;
664 kn
= kernfs_new_node(parent
, name
, mode
| S_IFDIR
, KERNFS_DIR
);
666 return ERR_PTR(-ENOMEM
);
668 kn
->dir
.root
= parent
->dir
.root
;
673 kernfs_addrm_start(&acxt
);
674 rc
= kernfs_add_one(&acxt
, kn
);
675 kernfs_addrm_finish(&acxt
);
684 static struct dentry
*kernfs_iop_lookup(struct inode
*dir
,
685 struct dentry
*dentry
,
689 struct kernfs_node
*parent
= dentry
->d_parent
->d_fsdata
;
690 struct kernfs_node
*kn
;
692 const void *ns
= NULL
;
694 mutex_lock(&kernfs_mutex
);
696 if (kernfs_ns_enabled(parent
))
697 ns
= kernfs_info(dir
->i_sb
)->ns
;
699 kn
= kernfs_find_ns(parent
, dentry
->d_name
.name
, ns
);
707 dentry
->d_fsdata
= kn
;
709 /* attach dentry and inode */
710 inode
= kernfs_get_inode(dir
->i_sb
, kn
);
712 ret
= ERR_PTR(-ENOMEM
);
716 /* instantiate and hash dentry */
717 ret
= d_materialise_unique(dentry
, inode
);
719 mutex_unlock(&kernfs_mutex
);
723 static int kernfs_iop_mkdir(struct inode
*dir
, struct dentry
*dentry
,
726 struct kernfs_node
*parent
= dir
->i_private
;
727 struct kernfs_dir_ops
*kdops
= kernfs_root(parent
)->dir_ops
;
729 if (!kdops
|| !kdops
->mkdir
)
732 return kdops
->mkdir(parent
, dentry
->d_name
.name
, mode
);
735 static int kernfs_iop_rmdir(struct inode
*dir
, struct dentry
*dentry
)
737 struct kernfs_node
*kn
= dentry
->d_fsdata
;
738 struct kernfs_dir_ops
*kdops
= kernfs_root(kn
)->dir_ops
;
740 if (!kdops
|| !kdops
->rmdir
)
743 return kdops
->rmdir(kn
);
746 static int kernfs_iop_rename(struct inode
*old_dir
, struct dentry
*old_dentry
,
747 struct inode
*new_dir
, struct dentry
*new_dentry
)
749 struct kernfs_node
*kn
= old_dentry
->d_fsdata
;
750 struct kernfs_node
*new_parent
= new_dir
->i_private
;
751 struct kernfs_dir_ops
*kdops
= kernfs_root(kn
)->dir_ops
;
753 if (!kdops
|| !kdops
->rename
)
756 return kdops
->rename(kn
, new_parent
, new_dentry
->d_name
.name
);
759 const struct inode_operations kernfs_dir_iops
= {
760 .lookup
= kernfs_iop_lookup
,
761 .permission
= kernfs_iop_permission
,
762 .setattr
= kernfs_iop_setattr
,
763 .getattr
= kernfs_iop_getattr
,
764 .setxattr
= kernfs_iop_setxattr
,
765 .removexattr
= kernfs_iop_removexattr
,
766 .getxattr
= kernfs_iop_getxattr
,
767 .listxattr
= kernfs_iop_listxattr
,
769 .mkdir
= kernfs_iop_mkdir
,
770 .rmdir
= kernfs_iop_rmdir
,
771 .rename
= kernfs_iop_rename
,
774 static struct kernfs_node
*kernfs_leftmost_descendant(struct kernfs_node
*pos
)
776 struct kernfs_node
*last
;
783 if (kernfs_type(pos
) != KERNFS_DIR
)
786 rbn
= rb_first(&pos
->dir
.children
);
797 * kernfs_next_descendant_post - find the next descendant for post-order walk
798 * @pos: the current position (%NULL to initiate traversal)
799 * @root: kernfs_node whose descendants to walk
801 * Find the next descendant to visit for post-order traversal of @root's
802 * descendants. @root is included in the iteration and the last node to be
805 static struct kernfs_node
*kernfs_next_descendant_post(struct kernfs_node
*pos
,
806 struct kernfs_node
*root
)
810 lockdep_assert_held(&kernfs_mutex
);
812 /* if first iteration, visit leftmost descendant which may be root */
814 return kernfs_leftmost_descendant(root
);
816 /* if we visited @root, we're done */
820 /* if there's an unvisited sibling, visit its leftmost descendant */
821 rbn
= rb_next(&pos
->rb
);
823 return kernfs_leftmost_descendant(rb_to_kn(rbn
));
825 /* no sibling left, visit parent */
829 static void __kernfs_remove(struct kernfs_addrm_cxt
*acxt
,
830 struct kernfs_node
*kn
)
832 struct kernfs_node
*pos
, *next
;
837 pr_debug("kernfs %s: removing\n", kn
->name
);
842 next
= kernfs_next_descendant_post(pos
, kn
);
844 kernfs_remove_one(acxt
, pos
);
849 * kernfs_remove - remove a kernfs_node recursively
850 * @kn: the kernfs_node to remove
852 * Remove @kn along with all its subdirectories and files.
854 void kernfs_remove(struct kernfs_node
*kn
)
856 struct kernfs_addrm_cxt acxt
;
858 kernfs_addrm_start(&acxt
);
859 __kernfs_remove(&acxt
, kn
);
860 kernfs_addrm_finish(&acxt
);
864 * kernfs_remove_by_name_ns - find a kernfs_node by name and remove it
865 * @parent: parent of the target
866 * @name: name of the kernfs_node to remove
867 * @ns: namespace tag of the kernfs_node to remove
869 * Look for the kernfs_node with @name and @ns under @parent and remove it.
870 * Returns 0 on success, -ENOENT if such entry doesn't exist.
872 int kernfs_remove_by_name_ns(struct kernfs_node
*parent
, const char *name
,
875 struct kernfs_addrm_cxt acxt
;
876 struct kernfs_node
*kn
;
879 WARN(1, KERN_WARNING
"kernfs: can not remove '%s', no directory\n",
884 kernfs_addrm_start(&acxt
);
886 kn
= kernfs_find_ns(parent
, name
, ns
);
888 __kernfs_remove(&acxt
, kn
);
890 kernfs_addrm_finish(&acxt
);
899 * kernfs_rename_ns - move and rename a kernfs_node
901 * @new_parent: new parent to put @sd under
902 * @new_name: new name
903 * @new_ns: new namespace tag
905 int kernfs_rename_ns(struct kernfs_node
*kn
, struct kernfs_node
*new_parent
,
906 const char *new_name
, const void *new_ns
)
910 mutex_lock(&kernfs_mutex
);
913 if ((kn
->flags
| new_parent
->flags
) & KERNFS_REMOVED
)
917 if ((kn
->parent
== new_parent
) && (kn
->ns
== new_ns
) &&
918 (strcmp(kn
->name
, new_name
) == 0))
919 goto out
; /* nothing to rename */
922 if (kernfs_find_ns(new_parent
, new_name
, new_ns
))
925 /* rename kernfs_node */
926 if (strcmp(kn
->name
, new_name
) != 0) {
928 new_name
= kstrdup(new_name
, GFP_KERNEL
);
932 if (kn
->flags
& KERNFS_STATIC_NAME
)
933 kn
->flags
&= ~KERNFS_STATIC_NAME
;
941 * Move to the appropriate place in the appropriate directories rbtree.
943 kernfs_unlink_sibling(kn
);
944 kernfs_get(new_parent
);
945 kernfs_put(kn
->parent
);
947 kn
->hash
= kernfs_name_hash(kn
->name
, kn
->ns
);
948 kn
->parent
= new_parent
;
949 kernfs_link_sibling(kn
);
953 mutex_unlock(&kernfs_mutex
);
957 /* Relationship between s_mode and the DT_xxx types */
958 static inline unsigned char dt_type(struct kernfs_node
*kn
)
960 return (kn
->mode
>> 12) & 15;
963 static int kernfs_dir_fop_release(struct inode
*inode
, struct file
*filp
)
965 kernfs_put(filp
->private_data
);
969 static struct kernfs_node
*kernfs_dir_pos(const void *ns
,
970 struct kernfs_node
*parent
, loff_t hash
, struct kernfs_node
*pos
)
973 int valid
= !(pos
->flags
& KERNFS_REMOVED
) &&
974 pos
->parent
== parent
&& hash
== pos
->hash
;
979 if (!pos
&& (hash
> 1) && (hash
< INT_MAX
)) {
980 struct rb_node
*node
= parent
->dir
.children
.rb_node
;
982 pos
= rb_to_kn(node
);
984 if (hash
< pos
->hash
)
985 node
= node
->rb_left
;
986 else if (hash
> pos
->hash
)
987 node
= node
->rb_right
;
992 /* Skip over entries in the wrong namespace */
993 while (pos
&& pos
->ns
!= ns
) {
994 struct rb_node
*node
= rb_next(&pos
->rb
);
998 pos
= rb_to_kn(node
);
1003 static struct kernfs_node
*kernfs_dir_next_pos(const void *ns
,
1004 struct kernfs_node
*parent
, ino_t ino
, struct kernfs_node
*pos
)
1006 pos
= kernfs_dir_pos(ns
, parent
, ino
, pos
);
1009 struct rb_node
*node
= rb_next(&pos
->rb
);
1013 pos
= rb_to_kn(node
);
1014 } while (pos
&& pos
->ns
!= ns
);
1018 static int kernfs_fop_readdir(struct file
*file
, struct dir_context
*ctx
)
1020 struct dentry
*dentry
= file
->f_path
.dentry
;
1021 struct kernfs_node
*parent
= dentry
->d_fsdata
;
1022 struct kernfs_node
*pos
= file
->private_data
;
1023 const void *ns
= NULL
;
1025 if (!dir_emit_dots(file
, ctx
))
1027 mutex_lock(&kernfs_mutex
);
1029 if (kernfs_ns_enabled(parent
))
1030 ns
= kernfs_info(dentry
->d_sb
)->ns
;
1032 for (pos
= kernfs_dir_pos(ns
, parent
, ctx
->pos
, pos
);
1034 pos
= kernfs_dir_next_pos(ns
, parent
, ctx
->pos
, pos
)) {
1035 const char *name
= pos
->name
;
1036 unsigned int type
= dt_type(pos
);
1037 int len
= strlen(name
);
1038 ino_t ino
= pos
->ino
;
1040 ctx
->pos
= pos
->hash
;
1041 file
->private_data
= pos
;
1044 mutex_unlock(&kernfs_mutex
);
1045 if (!dir_emit(ctx
, name
, len
, ino
, type
))
1047 mutex_lock(&kernfs_mutex
);
1049 mutex_unlock(&kernfs_mutex
);
1050 file
->private_data
= NULL
;
1055 static loff_t
kernfs_dir_fop_llseek(struct file
*file
, loff_t offset
,
1058 struct inode
*inode
= file_inode(file
);
1061 mutex_lock(&inode
->i_mutex
);
1062 ret
= generic_file_llseek(file
, offset
, whence
);
1063 mutex_unlock(&inode
->i_mutex
);
1068 const struct file_operations kernfs_dir_fops
= {
1069 .read
= generic_read_dir
,
1070 .iterate
= kernfs_fop_readdir
,
1071 .release
= kernfs_dir_fop_release
,
1072 .llseek
= kernfs_dir_fop_llseek
,