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 void kernfs_unlink_sibling(struct kernfs_node *kn)
126 if (kernfs_type(kn) == KERNFS_DIR)
127 kn->parent->dir.subdirs--;
129 rb_erase(&kn->rb, &kn->parent->dir.children);
133 * kernfs_get_active - get an active reference to kernfs_node
134 * @kn: kernfs_node to get an active reference to
136 * Get an active reference of @kn. This function is noop if @kn
140 * Pointer to @kn on success, NULL on failure.
142 struct kernfs_node *kernfs_get_active(struct kernfs_node *kn)
147 if (!atomic_inc_unless_negative(&kn->active))
150 if (kernfs_lockdep(kn))
151 rwsem_acquire_read(&kn->dep_map, 0, 1, _RET_IP_);
156 * kernfs_put_active - put an active reference to kernfs_node
157 * @kn: kernfs_node to put an active reference to
159 * Put an active reference to @kn. This function is noop if @kn
162 void kernfs_put_active(struct kernfs_node *kn)
164 struct kernfs_root *root = kernfs_root(kn);
170 if (kernfs_lockdep(kn))
171 rwsem_release(&kn->dep_map, 1, _RET_IP_);
172 v = atomic_dec_return(&kn->active);
173 if (likely(v != KN_DEACTIVATED_BIAS))
176 wake_up_all(&root->deactivate_waitq);
180 * kernfs_deactivate - deactivate kernfs_node
181 * @kn: kernfs_node to deactivate
183 * Deny new active references and drain existing ones.
185 static void kernfs_deactivate(struct kernfs_node *kn)
187 struct kernfs_root *root = kernfs_root(kn);
189 BUG_ON(!(kn->flags & KERNFS_REMOVED));
191 atomic_add(KN_DEACTIVATED_BIAS, &kn->active);
193 if (kernfs_lockdep(kn)) {
194 rwsem_acquire(&kn->dep_map, 0, 0, _RET_IP_);
195 if (atomic_read(&kn->active) != KN_DEACTIVATED_BIAS)
196 lock_contended(&kn->dep_map, _RET_IP_);
199 wait_event(root->deactivate_waitq,
200 atomic_read(&kn->active) == KN_DEACTIVATED_BIAS);
202 if (kernfs_lockdep(kn)) {
203 lock_acquired(&kn->dep_map, _RET_IP_);
204 rwsem_release(&kn->dep_map, 1, _RET_IP_);
209 * kernfs_get - get a reference count on a kernfs_node
210 * @kn: the target kernfs_node
212 void kernfs_get(struct kernfs_node *kn)
215 WARN_ON(!atomic_read(&kn->count));
216 atomic_inc(&kn->count);
219 EXPORT_SYMBOL_GPL(kernfs_get);
222 * kernfs_put - put a reference count on a kernfs_node
223 * @kn: the target kernfs_node
225 * Put a reference count of @kn and destroy it if it reached zero.
227 void kernfs_put(struct kernfs_node *kn)
229 struct kernfs_node *parent;
230 struct kernfs_root *root;
232 if (!kn || !atomic_dec_and_test(&kn->count))
234 root = kernfs_root(kn);
236 /* Moving/renaming is always done while holding reference.
237 * kn->parent won't change beneath us.
241 WARN(!(kn->flags & KERNFS_REMOVED), "kernfs: free using entry: %s/%s\n",
242 parent ? parent->name : "", kn->name);
244 if (kernfs_type(kn) == KERNFS_LINK)
245 kernfs_put(kn->symlink.target_kn);
246 if (!(kn->flags & KERNFS_STATIC_NAME))
249 if (kn->iattr->ia_secdata)
250 security_release_secctx(kn->iattr->ia_secdata,
251 kn->iattr->ia_secdata_len);
252 simple_xattrs_free(&kn->iattr->xattrs);
255 ida_simple_remove(&root->ino_ida, kn->ino);
256 kmem_cache_free(kernfs_node_cache, kn);
260 if (atomic_dec_and_test(&kn->count))
263 /* just released the root kn, free @root too */
264 ida_destroy(&root->ino_ida);
268 EXPORT_SYMBOL_GPL(kernfs_put);
270 static int kernfs_dop_revalidate(struct dentry *dentry, unsigned int flags)
272 struct kernfs_node *kn;
274 if (flags & LOOKUP_RCU)
277 /* Always perform fresh lookup for negatives */
278 if (!dentry->d_inode)
279 goto out_bad_unlocked;
281 kn = dentry->d_fsdata;
282 mutex_lock(&kernfs_mutex);
284 /* The kernfs node has been deleted */
285 if (kn->flags & KERNFS_REMOVED)
288 /* The kernfs node has been moved? */
289 if (dentry->d_parent->d_fsdata != kn->parent)
292 /* The kernfs node has been renamed */
293 if (strcmp(dentry->d_name.name, kn->name) != 0)
296 /* The kernfs node has been moved to a different namespace */
297 if (kn->parent && kernfs_ns_enabled(kn->parent) &&
298 kernfs_info(dentry->d_sb)->ns != kn->ns)
301 mutex_unlock(&kernfs_mutex);
305 mutex_unlock(&kernfs_mutex);
308 * @dentry doesn't match the underlying kernfs node, drop the
309 * dentry and force lookup. If we have submounts we must allow the
310 * vfs caches to lie about the state of the filesystem to prevent
311 * leaks and other nasty things, so use check_submounts_and_drop()
312 * instead of d_drop().
314 if (check_submounts_and_drop(dentry) != 0)
320 static void kernfs_dop_release(struct dentry *dentry)
322 kernfs_put(dentry->d_fsdata);
325 const struct dentry_operations kernfs_dops = {
326 .d_revalidate = kernfs_dop_revalidate,
327 .d_release = kernfs_dop_release,
330 struct kernfs_node *kernfs_new_node(struct kernfs_root *root, const char *name,
331 umode_t mode, unsigned flags)
333 char *dup_name = NULL;
334 struct kernfs_node *kn;
337 if (!(flags & KERNFS_STATIC_NAME)) {
338 name = dup_name = kstrdup(name, GFP_KERNEL);
343 kn = kmem_cache_zalloc(kernfs_node_cache, GFP_KERNEL);
347 ret = ida_simple_get(&root->ino_ida, 1, 0, GFP_KERNEL);
352 atomic_set(&kn->count, 1);
353 atomic_set(&kn->active, 0);
357 kn->flags = flags | KERNFS_REMOVED;
362 kmem_cache_free(kernfs_node_cache, kn);
369 * kernfs_addrm_start - prepare for kernfs_node add/remove
370 * @acxt: pointer to kernfs_addrm_cxt to be used
372 * This function is called when the caller is about to add or remove
373 * kernfs_node. This function acquires kernfs_mutex. @acxt is used
374 * to keep and pass context to other addrm functions.
377 * Kernel thread context (may sleep). kernfs_mutex is locked on
380 void kernfs_addrm_start(struct kernfs_addrm_cxt *acxt)
381 __acquires(kernfs_mutex)
383 memset(acxt, 0, sizeof(*acxt));
385 mutex_lock(&kernfs_mutex);
389 * kernfs_add_one - add kernfs_node to parent without warning
390 * @acxt: addrm context to use
391 * @kn: kernfs_node to be added
392 * @parent: the parent kernfs_node to add @kn to
394 * Get @parent and set @kn->parent to it and increment nlink of the
395 * parent inode if @kn is a directory and link into the children list
398 * This function should be called between calls to
399 * kernfs_addrm_start() and kernfs_addrm_finish() and should be passed
400 * the same @acxt as passed to kernfs_addrm_start().
403 * Determined by kernfs_addrm_start().
406 * 0 on success, -EEXIST if entry with the given name already
409 int kernfs_add_one(struct kernfs_addrm_cxt *acxt, struct kernfs_node *kn,
410 struct kernfs_node *parent)
412 bool has_ns = kernfs_ns_enabled(parent);
413 struct kernfs_iattrs *ps_iattr;
416 if (has_ns != (bool)kn->ns) {
417 WARN(1, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n",
418 has_ns ? "required" : "invalid", parent->name, kn->name);
422 if (kernfs_type(parent) != KERNFS_DIR)
425 if (parent->flags & KERNFS_REMOVED)
428 kn->hash = kernfs_name_hash(kn->name, kn->ns);
432 ret = kernfs_link_sibling(kn);
436 /* Update timestamps on the parent */
437 ps_iattr = parent->iattr;
439 struct iattr *ps_iattrs = &ps_iattr->ia_iattr;
440 ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME;
443 /* Mark the entry added into directory tree */
444 kn->flags &= ~KERNFS_REMOVED;
450 * kernfs_remove_one - remove kernfs_node from parent
451 * @acxt: addrm context to use
452 * @kn: kernfs_node to be removed
454 * Mark @kn removed and drop nlink of parent inode if @kn is a
455 * directory. @kn is unlinked from the children list.
457 * This function should be called between calls to
458 * kernfs_addrm_start() and kernfs_addrm_finish() and should be
459 * passed the same @acxt as passed to kernfs_addrm_start().
462 * Determined by kernfs_addrm_start().
464 static void kernfs_remove_one(struct kernfs_addrm_cxt *acxt,
465 struct kernfs_node *kn)
467 struct kernfs_iattrs *ps_iattr;
470 * Removal can be called multiple times on the same node. Only the
471 * first invocation is effective and puts the base ref.
473 if (kn->flags & KERNFS_REMOVED)
477 kernfs_unlink_sibling(kn);
479 /* Update timestamps on the parent */
480 ps_iattr = kn->parent->iattr;
482 ps_iattr->ia_iattr.ia_ctime = CURRENT_TIME;
483 ps_iattr->ia_iattr.ia_mtime = CURRENT_TIME;
487 kn->flags |= KERNFS_REMOVED;
488 kn->u.removed_list = acxt->removed;
493 * kernfs_addrm_finish - finish up kernfs_node add/remove
494 * @acxt: addrm context to finish up
496 * Finish up kernfs_node add/remove. Resources acquired by
497 * kernfs_addrm_start() are released and removed kernfs_nodes are
501 * kernfs_mutex is released.
503 void kernfs_addrm_finish(struct kernfs_addrm_cxt *acxt)
504 __releases(kernfs_mutex)
506 /* release resources acquired by kernfs_addrm_start() */
507 mutex_unlock(&kernfs_mutex);
509 /* kill removed kernfs_nodes */
510 while (acxt->removed) {
511 struct kernfs_node *kn = acxt->removed;
513 acxt->removed = kn->u.removed_list;
515 kernfs_deactivate(kn);
516 kernfs_unmap_bin_file(kn);
522 * kernfs_find_ns - find kernfs_node with the given name
523 * @parent: kernfs_node to search under
524 * @name: name to look for
525 * @ns: the namespace tag to use
527 * Look for kernfs_node with name @name under @parent. Returns pointer to
528 * the found kernfs_node on success, %NULL on failure.
530 static struct kernfs_node *kernfs_find_ns(struct kernfs_node *parent,
531 const unsigned char *name,
534 struct rb_node *node = parent->dir.children.rb_node;
535 bool has_ns = kernfs_ns_enabled(parent);
538 lockdep_assert_held(&kernfs_mutex);
540 if (has_ns != (bool)ns) {
541 WARN(1, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n",
542 has_ns ? "required" : "invalid", parent->name, name);
546 hash = kernfs_name_hash(name, ns);
548 struct kernfs_node *kn;
552 result = kernfs_name_compare(hash, name, ns, kn);
554 node = node->rb_left;
556 node = node->rb_right;
564 * kernfs_find_and_get_ns - find and get kernfs_node with the given name
565 * @parent: kernfs_node to search under
566 * @name: name to look for
567 * @ns: the namespace tag to use
569 * Look for kernfs_node with name @name under @parent and get a reference
570 * if found. This function may sleep and returns pointer to the found
571 * kernfs_node on success, %NULL on failure.
573 struct kernfs_node *kernfs_find_and_get_ns(struct kernfs_node *parent,
574 const char *name, const void *ns)
576 struct kernfs_node *kn;
578 mutex_lock(&kernfs_mutex);
579 kn = kernfs_find_ns(parent, name, ns);
581 mutex_unlock(&kernfs_mutex);
585 EXPORT_SYMBOL_GPL(kernfs_find_and_get_ns);
588 * kernfs_create_root - create a new kernfs hierarchy
589 * @kdops: optional directory syscall operations for the hierarchy
590 * @priv: opaque data associated with the new directory
592 * Returns the root of the new hierarchy on success, ERR_PTR() value on
595 struct kernfs_root *kernfs_create_root(struct kernfs_dir_ops *kdops, void *priv)
597 struct kernfs_root *root;
598 struct kernfs_node *kn;
600 root = kzalloc(sizeof(*root), GFP_KERNEL);
602 return ERR_PTR(-ENOMEM);
604 ida_init(&root->ino_ida);
606 kn = kernfs_new_node(root, "", S_IFDIR | S_IRUGO | S_IXUGO, KERNFS_DIR);
608 ida_destroy(&root->ino_ida);
610 return ERR_PTR(-ENOMEM);
613 kn->flags &= ~KERNFS_REMOVED;
617 root->dir_ops = kdops;
619 init_waitqueue_head(&root->deactivate_waitq);
625 * kernfs_destroy_root - destroy a kernfs hierarchy
626 * @root: root of the hierarchy to destroy
628 * Destroy the hierarchy anchored at @root by removing all existing
629 * directories and destroying @root.
631 void kernfs_destroy_root(struct kernfs_root *root)
633 kernfs_remove(root->kn); /* will also free @root */
637 * kernfs_create_dir_ns - create a directory
638 * @parent: parent in which to create a new directory
639 * @name: name of the new directory
640 * @mode: mode of the new directory
641 * @priv: opaque data associated with the new directory
642 * @ns: optional namespace tag of the directory
644 * Returns the created node on success, ERR_PTR() value on failure.
646 struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent,
647 const char *name, umode_t mode,
648 void *priv, const void *ns)
650 struct kernfs_addrm_cxt acxt;
651 struct kernfs_node *kn;
655 kn = kernfs_new_node(kernfs_root(parent), name, mode | S_IFDIR,
658 return ERR_PTR(-ENOMEM);
660 kn->dir.root = parent->dir.root;
665 kernfs_addrm_start(&acxt);
666 rc = kernfs_add_one(&acxt, kn, parent);
667 kernfs_addrm_finish(&acxt);
676 static struct dentry *kernfs_iop_lookup(struct inode *dir,
677 struct dentry *dentry,
681 struct kernfs_node *parent = dentry->d_parent->d_fsdata;
682 struct kernfs_node *kn;
684 const void *ns = NULL;
686 mutex_lock(&kernfs_mutex);
688 if (kernfs_ns_enabled(parent))
689 ns = kernfs_info(dir->i_sb)->ns;
691 kn = kernfs_find_ns(parent, dentry->d_name.name, ns);
699 dentry->d_fsdata = kn;
701 /* attach dentry and inode */
702 inode = kernfs_get_inode(dir->i_sb, kn);
704 ret = ERR_PTR(-ENOMEM);
708 /* instantiate and hash dentry */
709 ret = d_materialise_unique(dentry, inode);
711 mutex_unlock(&kernfs_mutex);
715 static int kernfs_iop_mkdir(struct inode *dir, struct dentry *dentry,
718 struct kernfs_node *parent = dir->i_private;
719 struct kernfs_dir_ops *kdops = kernfs_root(parent)->dir_ops;
721 if (!kdops || !kdops->mkdir)
724 return kdops->mkdir(parent, dentry->d_name.name, mode);
727 static int kernfs_iop_rmdir(struct inode *dir, struct dentry *dentry)
729 struct kernfs_node *kn = dentry->d_fsdata;
730 struct kernfs_dir_ops *kdops = kernfs_root(kn)->dir_ops;
732 if (!kdops || !kdops->rmdir)
735 return kdops->rmdir(kn);
738 static int kernfs_iop_rename(struct inode *old_dir, struct dentry *old_dentry,
739 struct inode *new_dir, struct dentry *new_dentry)
741 struct kernfs_node *kn = old_dentry->d_fsdata;
742 struct kernfs_node *new_parent = new_dir->i_private;
743 struct kernfs_dir_ops *kdops = kernfs_root(kn)->dir_ops;
745 if (!kdops || !kdops->rename)
748 return kdops->rename(kn, new_parent, new_dentry->d_name.name);
751 const struct inode_operations kernfs_dir_iops = {
752 .lookup = kernfs_iop_lookup,
753 .permission = kernfs_iop_permission,
754 .setattr = kernfs_iop_setattr,
755 .getattr = kernfs_iop_getattr,
756 .setxattr = kernfs_iop_setxattr,
757 .removexattr = kernfs_iop_removexattr,
758 .getxattr = kernfs_iop_getxattr,
759 .listxattr = kernfs_iop_listxattr,
761 .mkdir = kernfs_iop_mkdir,
762 .rmdir = kernfs_iop_rmdir,
763 .rename = kernfs_iop_rename,
766 static struct kernfs_node *kernfs_leftmost_descendant(struct kernfs_node *pos)
768 struct kernfs_node *last;
775 if (kernfs_type(pos) != KERNFS_DIR)
778 rbn = rb_first(&pos->dir.children);
789 * kernfs_next_descendant_post - find the next descendant for post-order walk
790 * @pos: the current position (%NULL to initiate traversal)
791 * @root: kernfs_node whose descendants to walk
793 * Find the next descendant to visit for post-order traversal of @root's
794 * descendants. @root is included in the iteration and the last node to be
797 static struct kernfs_node *kernfs_next_descendant_post(struct kernfs_node *pos,
798 struct kernfs_node *root)
802 lockdep_assert_held(&kernfs_mutex);
804 /* if first iteration, visit leftmost descendant which may be root */
806 return kernfs_leftmost_descendant(root);
808 /* if we visited @root, we're done */
812 /* if there's an unvisited sibling, visit its leftmost descendant */
813 rbn = rb_next(&pos->rb);
815 return kernfs_leftmost_descendant(rb_to_kn(rbn));
817 /* no sibling left, visit parent */
821 static void __kernfs_remove(struct kernfs_addrm_cxt *acxt,
822 struct kernfs_node *kn)
824 struct kernfs_node *pos, *next;
829 pr_debug("kernfs %s: removing\n", kn->name);
834 next = kernfs_next_descendant_post(pos, kn);
836 kernfs_remove_one(acxt, pos);
841 * kernfs_remove - remove a kernfs_node recursively
842 * @kn: the kernfs_node to remove
844 * Remove @kn along with all its subdirectories and files.
846 void kernfs_remove(struct kernfs_node *kn)
848 struct kernfs_addrm_cxt acxt;
850 kernfs_addrm_start(&acxt);
851 __kernfs_remove(&acxt, kn);
852 kernfs_addrm_finish(&acxt);
856 * kernfs_remove_by_name_ns - find a kernfs_node by name and remove it
857 * @parent: parent of the target
858 * @name: name of the kernfs_node to remove
859 * @ns: namespace tag of the kernfs_node to remove
861 * Look for the kernfs_node with @name and @ns under @parent and remove it.
862 * Returns 0 on success, -ENOENT if such entry doesn't exist.
864 int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name,
867 struct kernfs_addrm_cxt acxt;
868 struct kernfs_node *kn;
871 WARN(1, KERN_WARNING "kernfs: can not remove '%s', no directory\n",
876 kernfs_addrm_start(&acxt);
878 kn = kernfs_find_ns(parent, name, ns);
880 __kernfs_remove(&acxt, kn);
882 kernfs_addrm_finish(&acxt);
891 * kernfs_rename_ns - move and rename a kernfs_node
893 * @new_parent: new parent to put @sd under
894 * @new_name: new name
895 * @new_ns: new namespace tag
897 int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent,
898 const char *new_name, const void *new_ns)
902 mutex_lock(&kernfs_mutex);
905 if ((kn->flags | new_parent->flags) & KERNFS_REMOVED)
909 if ((kn->parent == new_parent) && (kn->ns == new_ns) &&
910 (strcmp(kn->name, new_name) == 0))
911 goto out; /* nothing to rename */
914 if (kernfs_find_ns(new_parent, new_name, new_ns))
917 /* rename kernfs_node */
918 if (strcmp(kn->name, new_name) != 0) {
920 new_name = kstrdup(new_name, GFP_KERNEL);
924 if (kn->flags & KERNFS_STATIC_NAME)
925 kn->flags &= ~KERNFS_STATIC_NAME;
933 * Move to the appropriate place in the appropriate directories rbtree.
935 kernfs_unlink_sibling(kn);
936 kernfs_get(new_parent);
937 kernfs_put(kn->parent);
939 kn->hash = kernfs_name_hash(kn->name, kn->ns);
940 kn->parent = new_parent;
941 kernfs_link_sibling(kn);
945 mutex_unlock(&kernfs_mutex);
949 /* Relationship between s_mode and the DT_xxx types */
950 static inline unsigned char dt_type(struct kernfs_node *kn)
952 return (kn->mode >> 12) & 15;
955 static int kernfs_dir_fop_release(struct inode *inode, struct file *filp)
957 kernfs_put(filp->private_data);
961 static struct kernfs_node *kernfs_dir_pos(const void *ns,
962 struct kernfs_node *parent, loff_t hash, struct kernfs_node *pos)
965 int valid = !(pos->flags & KERNFS_REMOVED) &&
966 pos->parent == parent && hash == pos->hash;
971 if (!pos && (hash > 1) && (hash < INT_MAX)) {
972 struct rb_node *node = parent->dir.children.rb_node;
974 pos = rb_to_kn(node);
976 if (hash < pos->hash)
977 node = node->rb_left;
978 else if (hash > pos->hash)
979 node = node->rb_right;
984 /* Skip over entries in the wrong namespace */
985 while (pos && pos->ns != ns) {
986 struct rb_node *node = rb_next(&pos->rb);
990 pos = rb_to_kn(node);
995 static struct kernfs_node *kernfs_dir_next_pos(const void *ns,
996 struct kernfs_node *parent, ino_t ino, struct kernfs_node *pos)
998 pos = kernfs_dir_pos(ns, parent, ino, pos);
1001 struct rb_node *node = rb_next(&pos->rb);
1005 pos = rb_to_kn(node);
1006 } while (pos && pos->ns != ns);
1010 static int kernfs_fop_readdir(struct file *file, struct dir_context *ctx)
1012 struct dentry *dentry = file->f_path.dentry;
1013 struct kernfs_node *parent = dentry->d_fsdata;
1014 struct kernfs_node *pos = file->private_data;
1015 const void *ns = NULL;
1017 if (!dir_emit_dots(file, ctx))
1019 mutex_lock(&kernfs_mutex);
1021 if (kernfs_ns_enabled(parent))
1022 ns = kernfs_info(dentry->d_sb)->ns;
1024 for (pos = kernfs_dir_pos(ns, parent, ctx->pos, pos);
1026 pos = kernfs_dir_next_pos(ns, parent, ctx->pos, pos)) {
1027 const char *name = pos->name;
1028 unsigned int type = dt_type(pos);
1029 int len = strlen(name);
1030 ino_t ino = pos->ino;
1032 ctx->pos = pos->hash;
1033 file->private_data = pos;
1036 mutex_unlock(&kernfs_mutex);
1037 if (!dir_emit(ctx, name, len, ino, type))
1039 mutex_lock(&kernfs_mutex);
1041 mutex_unlock(&kernfs_mutex);
1042 file->private_data = NULL;
1047 static loff_t kernfs_dir_fop_llseek(struct file *file, loff_t offset,
1050 struct inode *inode = file_inode(file);
1053 mutex_lock(&inode->i_mutex);
1054 ret = generic_file_llseek(file, offset, whence);
1055 mutex_unlock(&inode->i_mutex);
1060 const struct file_operations kernfs_dir_fops = {
1061 .read = generic_read_dir,
1062 .iterate = kernfs_fop_readdir,
1063 .release = kernfs_dir_fop_release,
1064 .llseek = kernfs_dir_fop_llseek,