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.
11 #include <linux/sched.h>
13 #include <linux/namei.h>
14 #include <linux/idr.h>
15 #include <linux/slab.h>
16 #include <linux/security.h>
17 #include <linux/hash.h>
19 #include "kernfs-internal.h"
21 DEFINE_MUTEX(kernfs_mutex);
23 #define rb_to_kn(X) rb_entry((X), struct kernfs_node, rb)
25 static bool kernfs_lockdep(struct kernfs_node *kn)
27 #ifdef CONFIG_DEBUG_LOCK_ALLOC
28 return kn->flags & KERNFS_LOCKDEP;
36 * @name: Null terminated string to hash
37 * @ns: Namespace tag to hash
39 * Returns 31 bit hash of ns + name (so it fits in an off_t )
41 static unsigned int kernfs_name_hash(const char *name, const void *ns)
43 unsigned long hash = init_name_hash();
44 unsigned int len = strlen(name);
46 hash = partial_name_hash(*name++, hash);
47 hash = (end_name_hash(hash) ^ hash_ptr((void *)ns, 31));
49 /* Reserve hash numbers 0, 1 and INT_MAX for magic directory entries */
57 static int kernfs_name_compare(unsigned int hash, const char *name,
58 const void *ns, const struct kernfs_node *kn)
61 return hash - kn->hash;
64 return strcmp(name, kn->name);
67 static int kernfs_sd_compare(const struct kernfs_node *left,
68 const struct kernfs_node *right)
70 return kernfs_name_compare(left->hash, left->name, left->ns, right);
74 * kernfs_link_sibling - link kernfs_node into sibling rbtree
75 * @kn: kernfs_node of interest
77 * Link @kn into its sibling rbtree which starts from
78 * @kn->parent->dir.children.
81 * mutex_lock(kernfs_mutex)
84 * 0 on susccess -EEXIST on failure.
86 static int kernfs_link_sibling(struct kernfs_node *kn)
88 struct rb_node **node = &kn->parent->dir.children.rb_node;
89 struct rb_node *parent = NULL;
91 if (kernfs_type(kn) == KERNFS_DIR)
92 kn->parent->dir.subdirs++;
95 struct kernfs_node *pos;
98 pos = rb_to_kn(*node);
100 result = kernfs_sd_compare(kn, pos);
102 node = &pos->rb.rb_left;
104 node = &pos->rb.rb_right;
108 /* add new node and rebalance the tree */
109 rb_link_node(&kn->rb, parent, node);
110 rb_insert_color(&kn->rb, &kn->parent->dir.children);
115 * kernfs_unlink_sibling - unlink kernfs_node from sibling rbtree
116 * @kn: kernfs_node of interest
118 * Unlink @kn from its sibling rbtree which starts from
119 * kn->parent->dir.children.
122 * mutex_lock(kernfs_mutex)
124 static bool kernfs_unlink_sibling(struct kernfs_node *kn)
126 if (RB_EMPTY_NODE(&kn->rb))
129 if (kernfs_type(kn) == KERNFS_DIR)
130 kn->parent->dir.subdirs--;
132 rb_erase(&kn->rb, &kn->parent->dir.children);
133 RB_CLEAR_NODE(&kn->rb);
138 * kernfs_get_active - get an active reference to kernfs_node
139 * @kn: kernfs_node to get an active reference to
141 * Get an active reference of @kn. This function is noop if @kn
145 * Pointer to @kn on success, NULL on failure.
147 struct kernfs_node *kernfs_get_active(struct kernfs_node *kn)
152 if (kernfs_lockdep(kn))
153 rwsem_acquire_read(&kn->dep_map, 0, 1, _RET_IP_);
156 * Try to obtain an active ref. If @kn is deactivated, we block
157 * till either it's reactivated or killed.
160 if (atomic_inc_unless_negative(&kn->active))
163 wait_event(kernfs_root(kn)->deactivate_waitq,
164 atomic_read(&kn->active) >= 0 ||
165 RB_EMPTY_NODE(&kn->rb));
166 } while (!RB_EMPTY_NODE(&kn->rb));
168 if (kernfs_lockdep(kn))
169 rwsem_release(&kn->dep_map, 1, _RET_IP_);
174 * kernfs_put_active - put an active reference to kernfs_node
175 * @kn: kernfs_node to put an active reference to
177 * Put an active reference to @kn. This function is noop if @kn
180 void kernfs_put_active(struct kernfs_node *kn)
182 struct kernfs_root *root = kernfs_root(kn);
188 if (kernfs_lockdep(kn))
189 rwsem_release(&kn->dep_map, 1, _RET_IP_);
190 v = atomic_dec_return(&kn->active);
191 if (likely(v != KN_DEACTIVATED_BIAS))
194 wake_up_all(&root->deactivate_waitq);
198 * kernfs_drain - drain kernfs_node
199 * @kn: kernfs_node to drain
201 * Drain existing usages of @kn. Mutiple removers may invoke this function
202 * concurrently on @kn and all will return after draining is complete.
203 * Returns %true if drain is performed and kernfs_mutex was temporarily
204 * released. %false if @kn was already drained and no operation was
207 * The caller is responsible for ensuring @kn stays pinned while this
208 * function is in progress even if it gets removed by someone else.
210 static bool kernfs_drain(struct kernfs_node *kn)
211 __releases(&kernfs_mutex) __acquires(&kernfs_mutex)
213 struct kernfs_root *root = kernfs_root(kn);
215 lockdep_assert_held(&kernfs_mutex);
216 WARN_ON_ONCE(atomic_read(&kn->active) >= 0);
219 * We want to go through the active ref lockdep annotation at least
220 * once for all node removals, but the lockdep annotation can't be
221 * nested inside kernfs_mutex and deactivation can't make forward
222 * progress if we keep dropping the mutex. Use JUST_ACTIVATED to
223 * force the slow path once for each deactivation if lockdep is
226 if ((!kernfs_lockdep(kn) || !(kn->flags & KERNFS_JUST_DEACTIVATED)) &&
227 atomic_read(&kn->active) == KN_DEACTIVATED_BIAS)
230 kn->flags &= ~KERNFS_JUST_DEACTIVATED;
231 mutex_unlock(&kernfs_mutex);
233 if (kernfs_lockdep(kn)) {
234 rwsem_acquire(&kn->dep_map, 0, 0, _RET_IP_);
235 if (atomic_read(&kn->active) != KN_DEACTIVATED_BIAS)
236 lock_contended(&kn->dep_map, _RET_IP_);
239 wait_event(root->deactivate_waitq,
240 atomic_read(&kn->active) == KN_DEACTIVATED_BIAS);
242 if (kernfs_lockdep(kn)) {
243 lock_acquired(&kn->dep_map, _RET_IP_);
244 rwsem_release(&kn->dep_map, 1, _RET_IP_);
247 mutex_lock(&kernfs_mutex);
252 * kernfs_get - get a reference count on a kernfs_node
253 * @kn: the target kernfs_node
255 void kernfs_get(struct kernfs_node *kn)
258 WARN_ON(!atomic_read(&kn->count));
259 atomic_inc(&kn->count);
262 EXPORT_SYMBOL_GPL(kernfs_get);
265 * kernfs_put - put a reference count on a kernfs_node
266 * @kn: the target kernfs_node
268 * Put a reference count of @kn and destroy it if it reached zero.
270 void kernfs_put(struct kernfs_node *kn)
272 struct kernfs_node *parent;
273 struct kernfs_root *root;
275 if (!kn || !atomic_dec_and_test(&kn->count))
277 root = kernfs_root(kn);
280 * Moving/renaming is always done while holding reference.
281 * kn->parent won't change beneath us.
285 WARN_ONCE(atomic_read(&kn->active) != KN_DEACTIVATED_BIAS,
286 "kernfs_put: %s/%s: released with incorrect active_ref %d\n",
287 parent ? parent->name : "", kn->name, atomic_read(&kn->active));
289 if (kernfs_type(kn) == KERNFS_LINK)
290 kernfs_put(kn->symlink.target_kn);
291 if (!(kn->flags & KERNFS_STATIC_NAME))
294 if (kn->iattr->ia_secdata)
295 security_release_secctx(kn->iattr->ia_secdata,
296 kn->iattr->ia_secdata_len);
297 simple_xattrs_free(&kn->iattr->xattrs);
300 ida_simple_remove(&root->ino_ida, kn->ino);
301 kmem_cache_free(kernfs_node_cache, kn);
305 if (atomic_dec_and_test(&kn->count))
308 /* just released the root kn, free @root too */
309 ida_destroy(&root->ino_ida);
313 EXPORT_SYMBOL_GPL(kernfs_put);
315 static int kernfs_dop_revalidate(struct dentry *dentry, unsigned int flags)
317 struct kernfs_node *kn;
319 if (flags & LOOKUP_RCU)
322 /* Always perform fresh lookup for negatives */
323 if (!dentry->d_inode)
324 goto out_bad_unlocked;
326 kn = dentry->d_fsdata;
327 mutex_lock(&kernfs_mutex);
329 /* Force fresh lookup if removed */
330 if (kn->parent && RB_EMPTY_NODE(&kn->rb))
333 /* The kernfs node has been moved? */
334 if (dentry->d_parent->d_fsdata != kn->parent)
337 /* The kernfs node has been renamed */
338 if (strcmp(dentry->d_name.name, kn->name) != 0)
341 /* The kernfs node has been moved to a different namespace */
342 if (kn->parent && kernfs_ns_enabled(kn->parent) &&
343 kernfs_info(dentry->d_sb)->ns != kn->ns)
346 mutex_unlock(&kernfs_mutex);
350 mutex_unlock(&kernfs_mutex);
353 * @dentry doesn't match the underlying kernfs node, drop the
354 * dentry and force lookup. If we have submounts we must allow the
355 * vfs caches to lie about the state of the filesystem to prevent
356 * leaks and other nasty things, so use check_submounts_and_drop()
357 * instead of d_drop().
359 if (check_submounts_and_drop(dentry) != 0)
365 static void kernfs_dop_release(struct dentry *dentry)
367 kernfs_put(dentry->d_fsdata);
370 const struct dentry_operations kernfs_dops = {
371 .d_revalidate = kernfs_dop_revalidate,
372 .d_release = kernfs_dop_release,
375 struct kernfs_node *kernfs_new_node(struct kernfs_root *root, const char *name,
376 umode_t mode, unsigned flags)
378 char *dup_name = NULL;
379 struct kernfs_node *kn;
382 if (!(flags & KERNFS_STATIC_NAME)) {
383 name = dup_name = kstrdup(name, GFP_KERNEL);
388 kn = kmem_cache_zalloc(kernfs_node_cache, GFP_KERNEL);
392 ret = ida_simple_get(&root->ino_ida, 1, 0, GFP_KERNEL);
397 atomic_set(&kn->count, 1);
398 atomic_set(&kn->active, KN_DEACTIVATED_BIAS);
399 RB_CLEAR_NODE(&kn->rb);
408 kmem_cache_free(kernfs_node_cache, kn);
415 * kernfs_add_one - add kernfs_node to parent without warning
416 * @kn: kernfs_node to be added
417 * @parent: the parent kernfs_node to add @kn to
419 * Get @parent and set @kn->parent to it and increment nlink of the
420 * parent inode if @kn is a directory and link into the children list
424 * 0 on success, -EEXIST if entry with the given name already
427 int kernfs_add_one(struct kernfs_node *kn, struct kernfs_node *parent)
429 struct kernfs_iattrs *ps_iattr;
433 if (!kernfs_get_active(parent))
436 mutex_lock(&kernfs_mutex);
439 has_ns = kernfs_ns_enabled(parent);
440 if (WARN(has_ns != (bool)kn->ns, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n",
441 has_ns ? "required" : "invalid", parent->name, kn->name))
444 if (kernfs_type(parent) != KERNFS_DIR)
447 kn->hash = kernfs_name_hash(kn->name, kn->ns);
451 ret = kernfs_link_sibling(kn);
455 /* Update timestamps on the parent */
456 ps_iattr = parent->iattr;
458 struct iattr *ps_iattrs = &ps_iattr->ia_iattr;
459 ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME;
462 /* Mark the entry added into directory tree */
463 atomic_sub(KN_DEACTIVATED_BIAS, &kn->active);
466 mutex_unlock(&kernfs_mutex);
467 kernfs_put_active(parent);
472 * kernfs_find_ns - find kernfs_node with the given name
473 * @parent: kernfs_node to search under
474 * @name: name to look for
475 * @ns: the namespace tag to use
477 * Look for kernfs_node with name @name under @parent. Returns pointer to
478 * the found kernfs_node on success, %NULL on failure.
480 static struct kernfs_node *kernfs_find_ns(struct kernfs_node *parent,
481 const unsigned char *name,
484 struct rb_node *node = parent->dir.children.rb_node;
485 bool has_ns = kernfs_ns_enabled(parent);
488 lockdep_assert_held(&kernfs_mutex);
490 if (has_ns != (bool)ns) {
491 WARN(1, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n",
492 has_ns ? "required" : "invalid", parent->name, name);
496 hash = kernfs_name_hash(name, ns);
498 struct kernfs_node *kn;
502 result = kernfs_name_compare(hash, name, ns, kn);
504 node = node->rb_left;
506 node = node->rb_right;
514 * kernfs_find_and_get_ns - find and get kernfs_node with the given name
515 * @parent: kernfs_node to search under
516 * @name: name to look for
517 * @ns: the namespace tag to use
519 * Look for kernfs_node with name @name under @parent and get a reference
520 * if found. This function may sleep and returns pointer to the found
521 * kernfs_node on success, %NULL on failure.
523 struct kernfs_node *kernfs_find_and_get_ns(struct kernfs_node *parent,
524 const char *name, const void *ns)
526 struct kernfs_node *kn;
528 mutex_lock(&kernfs_mutex);
529 kn = kernfs_find_ns(parent, name, ns);
531 mutex_unlock(&kernfs_mutex);
535 EXPORT_SYMBOL_GPL(kernfs_find_and_get_ns);
538 * kernfs_create_root - create a new kernfs hierarchy
539 * @kdops: optional directory syscall operations for the hierarchy
540 * @priv: opaque data associated with the new directory
542 * Returns the root of the new hierarchy on success, ERR_PTR() value on
545 struct kernfs_root *kernfs_create_root(struct kernfs_dir_ops *kdops, void *priv)
547 struct kernfs_root *root;
548 struct kernfs_node *kn;
550 root = kzalloc(sizeof(*root), GFP_KERNEL);
552 return ERR_PTR(-ENOMEM);
554 ida_init(&root->ino_ida);
556 kn = kernfs_new_node(root, "", S_IFDIR | S_IRUGO | S_IXUGO, KERNFS_DIR);
558 ida_destroy(&root->ino_ida);
560 return ERR_PTR(-ENOMEM);
563 atomic_sub(KN_DEACTIVATED_BIAS, &kn->active);
567 root->dir_ops = kdops;
569 init_waitqueue_head(&root->deactivate_waitq);
575 * kernfs_destroy_root - destroy a kernfs hierarchy
576 * @root: root of the hierarchy to destroy
578 * Destroy the hierarchy anchored at @root by removing all existing
579 * directories and destroying @root.
581 void kernfs_destroy_root(struct kernfs_root *root)
583 kernfs_remove(root->kn); /* will also free @root */
587 * kernfs_create_dir_ns - create a directory
588 * @parent: parent in which to create a new directory
589 * @name: name of the new directory
590 * @mode: mode of the new directory
591 * @priv: opaque data associated with the new directory
592 * @ns: optional namespace tag of the directory
594 * Returns the created node on success, ERR_PTR() value on failure.
596 struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent,
597 const char *name, umode_t mode,
598 void *priv, const void *ns)
600 struct kernfs_node *kn;
604 kn = kernfs_new_node(kernfs_root(parent), name, mode | S_IFDIR,
607 return ERR_PTR(-ENOMEM);
609 kn->dir.root = parent->dir.root;
614 rc = kernfs_add_one(kn, parent);
622 static struct dentry *kernfs_iop_lookup(struct inode *dir,
623 struct dentry *dentry,
627 struct kernfs_node *parent = dentry->d_parent->d_fsdata;
628 struct kernfs_node *kn;
630 const void *ns = NULL;
632 mutex_lock(&kernfs_mutex);
634 if (kernfs_ns_enabled(parent))
635 ns = kernfs_info(dir->i_sb)->ns;
637 kn = kernfs_find_ns(parent, dentry->d_name.name, ns);
645 dentry->d_fsdata = kn;
647 /* attach dentry and inode */
648 inode = kernfs_get_inode(dir->i_sb, kn);
650 ret = ERR_PTR(-ENOMEM);
654 /* instantiate and hash dentry */
655 ret = d_materialise_unique(dentry, inode);
657 mutex_unlock(&kernfs_mutex);
661 static int kernfs_iop_mkdir(struct inode *dir, struct dentry *dentry,
664 struct kernfs_node *parent = dir->i_private;
665 struct kernfs_dir_ops *kdops = kernfs_root(parent)->dir_ops;
667 if (!kdops || !kdops->mkdir)
670 return kdops->mkdir(parent, dentry->d_name.name, mode);
673 static int kernfs_iop_rmdir(struct inode *dir, struct dentry *dentry)
675 struct kernfs_node *kn = dentry->d_fsdata;
676 struct kernfs_dir_ops *kdops = kernfs_root(kn)->dir_ops;
678 if (!kdops || !kdops->rmdir)
681 return kdops->rmdir(kn);
684 static int kernfs_iop_rename(struct inode *old_dir, struct dentry *old_dentry,
685 struct inode *new_dir, struct dentry *new_dentry)
687 struct kernfs_node *kn = old_dentry->d_fsdata;
688 struct kernfs_node *new_parent = new_dir->i_private;
689 struct kernfs_dir_ops *kdops = kernfs_root(kn)->dir_ops;
691 if (!kdops || !kdops->rename)
694 return kdops->rename(kn, new_parent, new_dentry->d_name.name);
697 const struct inode_operations kernfs_dir_iops = {
698 .lookup = kernfs_iop_lookup,
699 .permission = kernfs_iop_permission,
700 .setattr = kernfs_iop_setattr,
701 .getattr = kernfs_iop_getattr,
702 .setxattr = kernfs_iop_setxattr,
703 .removexattr = kernfs_iop_removexattr,
704 .getxattr = kernfs_iop_getxattr,
705 .listxattr = kernfs_iop_listxattr,
707 .mkdir = kernfs_iop_mkdir,
708 .rmdir = kernfs_iop_rmdir,
709 .rename = kernfs_iop_rename,
712 static struct kernfs_node *kernfs_leftmost_descendant(struct kernfs_node *pos)
714 struct kernfs_node *last;
721 if (kernfs_type(pos) != KERNFS_DIR)
724 rbn = rb_first(&pos->dir.children);
735 * kernfs_next_descendant_post - find the next descendant for post-order walk
736 * @pos: the current position (%NULL to initiate traversal)
737 * @root: kernfs_node whose descendants to walk
739 * Find the next descendant to visit for post-order traversal of @root's
740 * descendants. @root is included in the iteration and the last node to be
743 static struct kernfs_node *kernfs_next_descendant_post(struct kernfs_node *pos,
744 struct kernfs_node *root)
748 lockdep_assert_held(&kernfs_mutex);
750 /* if first iteration, visit leftmost descendant which may be root */
752 return kernfs_leftmost_descendant(root);
754 /* if we visited @root, we're done */
758 /* if there's an unvisited sibling, visit its leftmost descendant */
759 rbn = rb_next(&pos->rb);
761 return kernfs_leftmost_descendant(rb_to_kn(rbn));
763 /* no sibling left, visit parent */
767 static void __kernfs_deactivate(struct kernfs_node *kn)
769 struct kernfs_node *pos;
771 lockdep_assert_held(&kernfs_mutex);
773 /* prevent any new usage under @kn by deactivating all nodes */
775 while ((pos = kernfs_next_descendant_post(pos, kn))) {
776 if (atomic_read(&pos->active) >= 0) {
777 atomic_add(KN_DEACTIVATED_BIAS, &pos->active);
778 pos->flags |= KERNFS_JUST_DEACTIVATED;
783 * Drain the subtree. If kernfs_drain() blocked to drain, which is
784 * indicated by %true return, it temporarily released kernfs_mutex
785 * and the rbtree might have been modified inbetween breaking our
786 * future walk. Restart the walk after each %true return.
789 while ((pos = kernfs_next_descendant_post(pos, kn))) {
793 drained = kernfs_drain(pos);
800 static void __kernfs_remove(struct kernfs_node *kn)
802 struct kernfs_root *root = kernfs_root(kn);
803 struct kernfs_node *pos;
805 lockdep_assert_held(&kernfs_mutex);
810 pr_debug("kernfs %s: removing\n", kn->name);
812 __kernfs_deactivate(kn);
814 /* unlink the subtree node-by-node */
816 pos = kernfs_leftmost_descendant(kn);
819 * We're gonna release kernfs_mutex to unmap bin files,
820 * Make sure @pos doesn't go away inbetween.
825 * This must be come before unlinking; otherwise, when
826 * there are multiple removers, some may finish before
827 * unmapping is complete.
829 if (pos->flags & KERNFS_HAS_MMAP) {
830 mutex_unlock(&kernfs_mutex);
831 kernfs_unmap_file(pos);
832 mutex_lock(&kernfs_mutex);
836 * kernfs_unlink_sibling() succeeds once per node. Use it
837 * to decide who's responsible for cleanups.
839 if (!pos->parent || kernfs_unlink_sibling(pos)) {
840 struct kernfs_iattrs *ps_iattr =
841 pos->parent ? pos->parent->iattr : NULL;
843 /* update timestamps on the parent */
845 ps_iattr->ia_iattr.ia_ctime = CURRENT_TIME;
846 ps_iattr->ia_iattr.ia_mtime = CURRENT_TIME;
855 /* some nodes killed, kick get_active waiters */
856 wake_up_all(&root->deactivate_waitq);
860 * kernfs_remove - remove a kernfs_node recursively
861 * @kn: the kernfs_node to remove
863 * Remove @kn along with all its subdirectories and files.
865 void kernfs_remove(struct kernfs_node *kn)
867 mutex_lock(&kernfs_mutex);
869 mutex_unlock(&kernfs_mutex);
873 * kernfs_remove_by_name_ns - find a kernfs_node by name and remove it
874 * @parent: parent of the target
875 * @name: name of the kernfs_node to remove
876 * @ns: namespace tag of the kernfs_node to remove
878 * Look for the kernfs_node with @name and @ns under @parent and remove it.
879 * Returns 0 on success, -ENOENT if such entry doesn't exist.
881 int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name,
884 struct kernfs_node *kn;
887 WARN(1, KERN_WARNING "kernfs: can not remove '%s', no directory\n",
892 mutex_lock(&kernfs_mutex);
894 kn = kernfs_find_ns(parent, name, ns);
898 mutex_unlock(&kernfs_mutex);
907 * kernfs_rename_ns - move and rename a kernfs_node
909 * @new_parent: new parent to put @sd under
910 * @new_name: new name
911 * @new_ns: new namespace tag
913 int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent,
914 const char *new_name, const void *new_ns)
919 if (!kernfs_get_active(new_parent))
921 if (!kernfs_get_active(kn))
922 goto out_put_new_parent;
924 mutex_lock(&kernfs_mutex);
927 if ((kn->parent == new_parent) && (kn->ns == new_ns) &&
928 (strcmp(kn->name, new_name) == 0))
929 goto out_unlock; /* nothing to rename */
932 if (kernfs_find_ns(new_parent, new_name, new_ns))
935 /* rename kernfs_node */
936 if (strcmp(kn->name, new_name) != 0) {
938 new_name = kstrdup(new_name, GFP_KERNEL);
942 if (kn->flags & KERNFS_STATIC_NAME)
943 kn->flags &= ~KERNFS_STATIC_NAME;
951 * Move to the appropriate place in the appropriate directories rbtree.
953 kernfs_unlink_sibling(kn);
954 kernfs_get(new_parent);
955 kernfs_put(kn->parent);
957 kn->hash = kernfs_name_hash(kn->name, kn->ns);
958 kn->parent = new_parent;
959 kernfs_link_sibling(kn);
963 mutex_unlock(&kernfs_mutex);
964 kernfs_put_active(kn);
966 kernfs_put_active(new_parent);
971 /* Relationship between s_mode and the DT_xxx types */
972 static inline unsigned char dt_type(struct kernfs_node *kn)
974 return (kn->mode >> 12) & 15;
977 static int kernfs_dir_fop_release(struct inode *inode, struct file *filp)
979 kernfs_put(filp->private_data);
983 static struct kernfs_node *kernfs_dir_pos(const void *ns,
984 struct kernfs_node *parent, loff_t hash, struct kernfs_node *pos)
987 int valid = pos->parent == parent && hash == pos->hash;
992 if (!pos && (hash > 1) && (hash < INT_MAX)) {
993 struct rb_node *node = parent->dir.children.rb_node;
995 pos = rb_to_kn(node);
997 if (hash < pos->hash)
998 node = node->rb_left;
999 else if (hash > pos->hash)
1000 node = node->rb_right;
1005 /* Skip over entries in the wrong namespace */
1006 while (pos && pos->ns != ns) {
1007 struct rb_node *node = rb_next(&pos->rb);
1011 pos = rb_to_kn(node);
1016 static struct kernfs_node *kernfs_dir_next_pos(const void *ns,
1017 struct kernfs_node *parent, ino_t ino, struct kernfs_node *pos)
1019 pos = kernfs_dir_pos(ns, parent, ino, pos);
1022 struct rb_node *node = rb_next(&pos->rb);
1026 pos = rb_to_kn(node);
1027 } while (pos && pos->ns != ns);
1031 static int kernfs_fop_readdir(struct file *file, struct dir_context *ctx)
1033 struct dentry *dentry = file->f_path.dentry;
1034 struct kernfs_node *parent = dentry->d_fsdata;
1035 struct kernfs_node *pos = file->private_data;
1036 const void *ns = NULL;
1038 if (!dir_emit_dots(file, ctx))
1040 mutex_lock(&kernfs_mutex);
1042 if (kernfs_ns_enabled(parent))
1043 ns = kernfs_info(dentry->d_sb)->ns;
1045 for (pos = kernfs_dir_pos(ns, parent, ctx->pos, pos);
1047 pos = kernfs_dir_next_pos(ns, parent, ctx->pos, pos)) {
1048 const char *name = pos->name;
1049 unsigned int type = dt_type(pos);
1050 int len = strlen(name);
1051 ino_t ino = pos->ino;
1053 ctx->pos = pos->hash;
1054 file->private_data = pos;
1057 mutex_unlock(&kernfs_mutex);
1058 if (!dir_emit(ctx, name, len, ino, type))
1060 mutex_lock(&kernfs_mutex);
1062 mutex_unlock(&kernfs_mutex);
1063 file->private_data = NULL;
1068 static loff_t kernfs_dir_fop_llseek(struct file *file, loff_t offset,
1071 struct inode *inode = file_inode(file);
1074 mutex_lock(&inode->i_mutex);
1075 ret = generic_file_llseek(file, offset, whence);
1076 mutex_unlock(&inode->i_mutex);
1081 const struct file_operations kernfs_dir_fops = {
1082 .read = generic_read_dir,
1083 .iterate = kernfs_fop_readdir,
1084 .release = kernfs_dir_fop_release,
1085 .llseek = kernfs_dir_fop_llseek,