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 (!atomic_inc_unless_negative(&kn->active))
155 if (kernfs_lockdep(kn))
156 rwsem_acquire_read(&kn->dep_map, 0, 1, _RET_IP_);
161 * kernfs_put_active - put an active reference to kernfs_node
162 * @kn: kernfs_node to put an active reference to
164 * Put an active reference to @kn. This function is noop if @kn
167 void kernfs_put_active(struct kernfs_node *kn)
169 struct kernfs_root *root = kernfs_root(kn);
175 if (kernfs_lockdep(kn))
176 rwsem_release(&kn->dep_map, 1, _RET_IP_);
177 v = atomic_dec_return(&kn->active);
178 if (likely(v != KN_DEACTIVATED_BIAS))
181 wake_up_all(&root->deactivate_waitq);
185 * kernfs_drain - drain kernfs_node
186 * @kn: kernfs_node to drain
188 * Drain existing usages of @kn. Mutiple removers may invoke this function
189 * concurrently on @kn and all will return after draining is complete.
190 * Returns %true if drain is performed and kernfs_mutex was temporarily
191 * released. %false if @kn was already drained and no operation was
194 * The caller is responsible for ensuring @kn stays pinned while this
195 * function is in progress even if it gets removed by someone else.
197 static bool kernfs_drain(struct kernfs_node *kn)
198 __releases(&kernfs_mutex) __acquires(&kernfs_mutex)
200 struct kernfs_root *root = kernfs_root(kn);
202 lockdep_assert_held(&kernfs_mutex);
203 WARN_ON_ONCE(atomic_read(&kn->active) >= 0);
206 * We want to go through the active ref lockdep annotation at least
207 * once for all node removals, but the lockdep annotation can't be
208 * nested inside kernfs_mutex and deactivation can't make forward
209 * progress if we keep dropping the mutex. Use JUST_ACTIVATED to
210 * force the slow path once for each deactivation if lockdep is
213 if ((!kernfs_lockdep(kn) || !(kn->flags & KERNFS_JUST_DEACTIVATED)) &&
214 atomic_read(&kn->active) == KN_DEACTIVATED_BIAS)
217 kn->flags &= ~KERNFS_JUST_DEACTIVATED;
218 mutex_unlock(&kernfs_mutex);
220 if (kernfs_lockdep(kn)) {
221 rwsem_acquire(&kn->dep_map, 0, 0, _RET_IP_);
222 if (atomic_read(&kn->active) != KN_DEACTIVATED_BIAS)
223 lock_contended(&kn->dep_map, _RET_IP_);
226 wait_event(root->deactivate_waitq,
227 atomic_read(&kn->active) == KN_DEACTIVATED_BIAS);
229 if (kernfs_lockdep(kn)) {
230 lock_acquired(&kn->dep_map, _RET_IP_);
231 rwsem_release(&kn->dep_map, 1, _RET_IP_);
234 mutex_lock(&kernfs_mutex);
239 * kernfs_get - get a reference count on a kernfs_node
240 * @kn: the target kernfs_node
242 void kernfs_get(struct kernfs_node *kn)
245 WARN_ON(!atomic_read(&kn->count));
246 atomic_inc(&kn->count);
249 EXPORT_SYMBOL_GPL(kernfs_get);
252 * kernfs_put - put a reference count on a kernfs_node
253 * @kn: the target kernfs_node
255 * Put a reference count of @kn and destroy it if it reached zero.
257 void kernfs_put(struct kernfs_node *kn)
259 struct kernfs_node *parent;
260 struct kernfs_root *root;
262 if (!kn || !atomic_dec_and_test(&kn->count))
264 root = kernfs_root(kn);
267 * Moving/renaming is always done while holding reference.
268 * kn->parent won't change beneath us.
272 WARN_ONCE(atomic_read(&kn->active) != KN_DEACTIVATED_BIAS,
273 "kernfs_put: %s/%s: released with incorrect active_ref %d\n",
274 parent ? parent->name : "", kn->name, atomic_read(&kn->active));
276 if (kernfs_type(kn) == KERNFS_LINK)
277 kernfs_put(kn->symlink.target_kn);
278 if (!(kn->flags & KERNFS_STATIC_NAME))
281 if (kn->iattr->ia_secdata)
282 security_release_secctx(kn->iattr->ia_secdata,
283 kn->iattr->ia_secdata_len);
284 simple_xattrs_free(&kn->iattr->xattrs);
287 ida_simple_remove(&root->ino_ida, kn->ino);
288 kmem_cache_free(kernfs_node_cache, kn);
292 if (atomic_dec_and_test(&kn->count))
295 /* just released the root kn, free @root too */
296 ida_destroy(&root->ino_ida);
300 EXPORT_SYMBOL_GPL(kernfs_put);
302 static int kernfs_dop_revalidate(struct dentry *dentry, unsigned int flags)
304 struct kernfs_node *kn;
306 if (flags & LOOKUP_RCU)
309 /* Always perform fresh lookup for negatives */
310 if (!dentry->d_inode)
311 goto out_bad_unlocked;
313 kn = dentry->d_fsdata;
314 mutex_lock(&kernfs_mutex);
316 /* Force fresh lookup if removed */
317 if (kn->parent && RB_EMPTY_NODE(&kn->rb))
320 /* The kernfs node has been moved? */
321 if (dentry->d_parent->d_fsdata != kn->parent)
324 /* The kernfs node has been renamed */
325 if (strcmp(dentry->d_name.name, kn->name) != 0)
328 /* The kernfs node has been moved to a different namespace */
329 if (kn->parent && kernfs_ns_enabled(kn->parent) &&
330 kernfs_info(dentry->d_sb)->ns != kn->ns)
333 mutex_unlock(&kernfs_mutex);
337 mutex_unlock(&kernfs_mutex);
340 * @dentry doesn't match the underlying kernfs node, drop the
341 * dentry and force lookup. If we have submounts we must allow the
342 * vfs caches to lie about the state of the filesystem to prevent
343 * leaks and other nasty things, so use check_submounts_and_drop()
344 * instead of d_drop().
346 if (check_submounts_and_drop(dentry) != 0)
352 static void kernfs_dop_release(struct dentry *dentry)
354 kernfs_put(dentry->d_fsdata);
357 const struct dentry_operations kernfs_dops = {
358 .d_revalidate = kernfs_dop_revalidate,
359 .d_release = kernfs_dop_release,
362 struct kernfs_node *kernfs_new_node(struct kernfs_root *root, const char *name,
363 umode_t mode, unsigned flags)
365 char *dup_name = NULL;
366 struct kernfs_node *kn;
369 if (!(flags & KERNFS_STATIC_NAME)) {
370 name = dup_name = kstrdup(name, GFP_KERNEL);
375 kn = kmem_cache_zalloc(kernfs_node_cache, GFP_KERNEL);
379 ret = ida_simple_get(&root->ino_ida, 1, 0, GFP_KERNEL);
384 atomic_set(&kn->count, 1);
385 atomic_set(&kn->active, KN_DEACTIVATED_BIAS);
386 RB_CLEAR_NODE(&kn->rb);
395 kmem_cache_free(kernfs_node_cache, kn);
402 * kernfs_add_one - add kernfs_node to parent without warning
403 * @kn: kernfs_node to be added
404 * @parent: the parent kernfs_node to add @kn to
406 * Get @parent and set @kn->parent to it and increment nlink of the
407 * parent inode if @kn is a directory and link into the children list
411 * 0 on success, -EEXIST if entry with the given name already
414 int kernfs_add_one(struct kernfs_node *kn, struct kernfs_node *parent)
416 struct kernfs_iattrs *ps_iattr;
420 if (!kernfs_get_active(parent))
423 mutex_lock(&kernfs_mutex);
426 has_ns = kernfs_ns_enabled(parent);
427 if (WARN(has_ns != (bool)kn->ns, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n",
428 has_ns ? "required" : "invalid", parent->name, kn->name))
431 if (kernfs_type(parent) != KERNFS_DIR)
434 kn->hash = kernfs_name_hash(kn->name, kn->ns);
438 ret = kernfs_link_sibling(kn);
442 /* Update timestamps on the parent */
443 ps_iattr = parent->iattr;
445 struct iattr *ps_iattrs = &ps_iattr->ia_iattr;
446 ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME;
449 /* Mark the entry added into directory tree */
450 atomic_sub(KN_DEACTIVATED_BIAS, &kn->active);
453 mutex_unlock(&kernfs_mutex);
454 kernfs_put_active(parent);
459 * kernfs_find_ns - find kernfs_node with the given name
460 * @parent: kernfs_node to search under
461 * @name: name to look for
462 * @ns: the namespace tag to use
464 * Look for kernfs_node with name @name under @parent. Returns pointer to
465 * the found kernfs_node on success, %NULL on failure.
467 static struct kernfs_node *kernfs_find_ns(struct kernfs_node *parent,
468 const unsigned char *name,
471 struct rb_node *node = parent->dir.children.rb_node;
472 bool has_ns = kernfs_ns_enabled(parent);
475 lockdep_assert_held(&kernfs_mutex);
477 if (has_ns != (bool)ns) {
478 WARN(1, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n",
479 has_ns ? "required" : "invalid", parent->name, name);
483 hash = kernfs_name_hash(name, ns);
485 struct kernfs_node *kn;
489 result = kernfs_name_compare(hash, name, ns, kn);
491 node = node->rb_left;
493 node = node->rb_right;
501 * kernfs_find_and_get_ns - find and get kernfs_node with the given name
502 * @parent: kernfs_node to search under
503 * @name: name to look for
504 * @ns: the namespace tag to use
506 * Look for kernfs_node with name @name under @parent and get a reference
507 * if found. This function may sleep and returns pointer to the found
508 * kernfs_node on success, %NULL on failure.
510 struct kernfs_node *kernfs_find_and_get_ns(struct kernfs_node *parent,
511 const char *name, const void *ns)
513 struct kernfs_node *kn;
515 mutex_lock(&kernfs_mutex);
516 kn = kernfs_find_ns(parent, name, ns);
518 mutex_unlock(&kernfs_mutex);
522 EXPORT_SYMBOL_GPL(kernfs_find_and_get_ns);
525 * kernfs_create_root - create a new kernfs hierarchy
526 * @kdops: optional directory syscall operations for the hierarchy
527 * @priv: opaque data associated with the new directory
529 * Returns the root of the new hierarchy on success, ERR_PTR() value on
532 struct kernfs_root *kernfs_create_root(struct kernfs_dir_ops *kdops, void *priv)
534 struct kernfs_root *root;
535 struct kernfs_node *kn;
537 root = kzalloc(sizeof(*root), GFP_KERNEL);
539 return ERR_PTR(-ENOMEM);
541 ida_init(&root->ino_ida);
543 kn = kernfs_new_node(root, "", S_IFDIR | S_IRUGO | S_IXUGO, KERNFS_DIR);
545 ida_destroy(&root->ino_ida);
547 return ERR_PTR(-ENOMEM);
550 atomic_sub(KN_DEACTIVATED_BIAS, &kn->active);
554 root->dir_ops = kdops;
556 init_waitqueue_head(&root->deactivate_waitq);
562 * kernfs_destroy_root - destroy a kernfs hierarchy
563 * @root: root of the hierarchy to destroy
565 * Destroy the hierarchy anchored at @root by removing all existing
566 * directories and destroying @root.
568 void kernfs_destroy_root(struct kernfs_root *root)
570 kernfs_remove(root->kn); /* will also free @root */
574 * kernfs_create_dir_ns - create a directory
575 * @parent: parent in which to create a new directory
576 * @name: name of the new directory
577 * @mode: mode of the new directory
578 * @priv: opaque data associated with the new directory
579 * @ns: optional namespace tag of the directory
581 * Returns the created node on success, ERR_PTR() value on failure.
583 struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent,
584 const char *name, umode_t mode,
585 void *priv, const void *ns)
587 struct kernfs_node *kn;
591 kn = kernfs_new_node(kernfs_root(parent), name, mode | S_IFDIR,
594 return ERR_PTR(-ENOMEM);
596 kn->dir.root = parent->dir.root;
601 rc = kernfs_add_one(kn, parent);
609 static struct dentry *kernfs_iop_lookup(struct inode *dir,
610 struct dentry *dentry,
614 struct kernfs_node *parent = dentry->d_parent->d_fsdata;
615 struct kernfs_node *kn;
617 const void *ns = NULL;
619 mutex_lock(&kernfs_mutex);
621 if (kernfs_ns_enabled(parent))
622 ns = kernfs_info(dir->i_sb)->ns;
624 kn = kernfs_find_ns(parent, dentry->d_name.name, ns);
632 dentry->d_fsdata = kn;
634 /* attach dentry and inode */
635 inode = kernfs_get_inode(dir->i_sb, kn);
637 ret = ERR_PTR(-ENOMEM);
641 /* instantiate and hash dentry */
642 ret = d_materialise_unique(dentry, inode);
644 mutex_unlock(&kernfs_mutex);
648 static int kernfs_iop_mkdir(struct inode *dir, struct dentry *dentry,
651 struct kernfs_node *parent = dir->i_private;
652 struct kernfs_dir_ops *kdops = kernfs_root(parent)->dir_ops;
654 if (!kdops || !kdops->mkdir)
657 return kdops->mkdir(parent, dentry->d_name.name, mode);
660 static int kernfs_iop_rmdir(struct inode *dir, struct dentry *dentry)
662 struct kernfs_node *kn = dentry->d_fsdata;
663 struct kernfs_dir_ops *kdops = kernfs_root(kn)->dir_ops;
665 if (!kdops || !kdops->rmdir)
668 return kdops->rmdir(kn);
671 static int kernfs_iop_rename(struct inode *old_dir, struct dentry *old_dentry,
672 struct inode *new_dir, struct dentry *new_dentry)
674 struct kernfs_node *kn = old_dentry->d_fsdata;
675 struct kernfs_node *new_parent = new_dir->i_private;
676 struct kernfs_dir_ops *kdops = kernfs_root(kn)->dir_ops;
678 if (!kdops || !kdops->rename)
681 return kdops->rename(kn, new_parent, new_dentry->d_name.name);
684 const struct inode_operations kernfs_dir_iops = {
685 .lookup = kernfs_iop_lookup,
686 .permission = kernfs_iop_permission,
687 .setattr = kernfs_iop_setattr,
688 .getattr = kernfs_iop_getattr,
689 .setxattr = kernfs_iop_setxattr,
690 .removexattr = kernfs_iop_removexattr,
691 .getxattr = kernfs_iop_getxattr,
692 .listxattr = kernfs_iop_listxattr,
694 .mkdir = kernfs_iop_mkdir,
695 .rmdir = kernfs_iop_rmdir,
696 .rename = kernfs_iop_rename,
699 static struct kernfs_node *kernfs_leftmost_descendant(struct kernfs_node *pos)
701 struct kernfs_node *last;
708 if (kernfs_type(pos) != KERNFS_DIR)
711 rbn = rb_first(&pos->dir.children);
722 * kernfs_next_descendant_post - find the next descendant for post-order walk
723 * @pos: the current position (%NULL to initiate traversal)
724 * @root: kernfs_node whose descendants to walk
726 * Find the next descendant to visit for post-order traversal of @root's
727 * descendants. @root is included in the iteration and the last node to be
730 static struct kernfs_node *kernfs_next_descendant_post(struct kernfs_node *pos,
731 struct kernfs_node *root)
735 lockdep_assert_held(&kernfs_mutex);
737 /* if first iteration, visit leftmost descendant which may be root */
739 return kernfs_leftmost_descendant(root);
741 /* if we visited @root, we're done */
745 /* if there's an unvisited sibling, visit its leftmost descendant */
746 rbn = rb_next(&pos->rb);
748 return kernfs_leftmost_descendant(rb_to_kn(rbn));
750 /* no sibling left, visit parent */
754 static void __kernfs_deactivate(struct kernfs_node *kn)
756 struct kernfs_node *pos;
758 lockdep_assert_held(&kernfs_mutex);
760 /* prevent any new usage under @kn by deactivating all nodes */
762 while ((pos = kernfs_next_descendant_post(pos, kn))) {
763 if (atomic_read(&pos->active) >= 0) {
764 atomic_add(KN_DEACTIVATED_BIAS, &pos->active);
765 pos->flags |= KERNFS_JUST_DEACTIVATED;
770 * Drain the subtree. If kernfs_drain() blocked to drain, which is
771 * indicated by %true return, it temporarily released kernfs_mutex
772 * and the rbtree might have been modified inbetween breaking our
773 * future walk. Restart the walk after each %true return.
776 while ((pos = kernfs_next_descendant_post(pos, kn))) {
780 drained = kernfs_drain(pos);
787 static void __kernfs_remove(struct kernfs_node *kn)
789 struct kernfs_node *pos;
791 lockdep_assert_held(&kernfs_mutex);
796 pr_debug("kernfs %s: removing\n", kn->name);
798 __kernfs_deactivate(kn);
800 /* unlink the subtree node-by-node */
802 pos = kernfs_leftmost_descendant(kn);
805 * We're gonna release kernfs_mutex to unmap bin files,
806 * Make sure @pos doesn't go away inbetween.
811 * This must be come before unlinking; otherwise, when
812 * there are multiple removers, some may finish before
813 * unmapping is complete.
815 if (pos->flags & KERNFS_HAS_MMAP) {
816 mutex_unlock(&kernfs_mutex);
817 kernfs_unmap_file(pos);
818 mutex_lock(&kernfs_mutex);
822 * kernfs_unlink_sibling() succeeds once per node. Use it
823 * to decide who's responsible for cleanups.
825 if (!pos->parent || kernfs_unlink_sibling(pos)) {
826 struct kernfs_iattrs *ps_iattr =
827 pos->parent ? pos->parent->iattr : NULL;
829 /* update timestamps on the parent */
831 ps_iattr->ia_iattr.ia_ctime = CURRENT_TIME;
832 ps_iattr->ia_iattr.ia_mtime = CURRENT_TIME;
843 * kernfs_remove - remove a kernfs_node recursively
844 * @kn: the kernfs_node to remove
846 * Remove @kn along with all its subdirectories and files.
848 void kernfs_remove(struct kernfs_node *kn)
850 mutex_lock(&kernfs_mutex);
852 mutex_unlock(&kernfs_mutex);
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_node *kn;
870 WARN(1, KERN_WARNING "kernfs: can not remove '%s', no directory\n",
875 mutex_lock(&kernfs_mutex);
877 kn = kernfs_find_ns(parent, name, ns);
881 mutex_unlock(&kernfs_mutex);
890 * kernfs_rename_ns - move and rename a kernfs_node
892 * @new_parent: new parent to put @sd under
893 * @new_name: new name
894 * @new_ns: new namespace tag
896 int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent,
897 const char *new_name, const void *new_ns)
902 if (!kernfs_get_active(new_parent))
904 if (!kernfs_get_active(kn))
905 goto out_put_new_parent;
907 mutex_lock(&kernfs_mutex);
910 if ((kn->parent == new_parent) && (kn->ns == new_ns) &&
911 (strcmp(kn->name, new_name) == 0))
912 goto out_unlock; /* nothing to rename */
915 if (kernfs_find_ns(new_parent, new_name, new_ns))
918 /* rename kernfs_node */
919 if (strcmp(kn->name, new_name) != 0) {
921 new_name = kstrdup(new_name, GFP_KERNEL);
925 if (kn->flags & KERNFS_STATIC_NAME)
926 kn->flags &= ~KERNFS_STATIC_NAME;
934 * Move to the appropriate place in the appropriate directories rbtree.
936 kernfs_unlink_sibling(kn);
937 kernfs_get(new_parent);
938 kernfs_put(kn->parent);
940 kn->hash = kernfs_name_hash(kn->name, kn->ns);
941 kn->parent = new_parent;
942 kernfs_link_sibling(kn);
946 mutex_unlock(&kernfs_mutex);
947 kernfs_put_active(kn);
949 kernfs_put_active(new_parent);
954 /* Relationship between s_mode and the DT_xxx types */
955 static inline unsigned char dt_type(struct kernfs_node *kn)
957 return (kn->mode >> 12) & 15;
960 static int kernfs_dir_fop_release(struct inode *inode, struct file *filp)
962 kernfs_put(filp->private_data);
966 static struct kernfs_node *kernfs_dir_pos(const void *ns,
967 struct kernfs_node *parent, loff_t hash, struct kernfs_node *pos)
970 int valid = pos->parent == parent && hash == pos->hash;
975 if (!pos && (hash > 1) && (hash < INT_MAX)) {
976 struct rb_node *node = parent->dir.children.rb_node;
978 pos = rb_to_kn(node);
980 if (hash < pos->hash)
981 node = node->rb_left;
982 else if (hash > pos->hash)
983 node = node->rb_right;
988 /* Skip over entries in the wrong namespace */
989 while (pos && pos->ns != ns) {
990 struct rb_node *node = rb_next(&pos->rb);
994 pos = rb_to_kn(node);
999 static struct kernfs_node *kernfs_dir_next_pos(const void *ns,
1000 struct kernfs_node *parent, ino_t ino, struct kernfs_node *pos)
1002 pos = kernfs_dir_pos(ns, parent, ino, pos);
1005 struct rb_node *node = rb_next(&pos->rb);
1009 pos = rb_to_kn(node);
1010 } while (pos && pos->ns != ns);
1014 static int kernfs_fop_readdir(struct file *file, struct dir_context *ctx)
1016 struct dentry *dentry = file->f_path.dentry;
1017 struct kernfs_node *parent = dentry->d_fsdata;
1018 struct kernfs_node *pos = file->private_data;
1019 const void *ns = NULL;
1021 if (!dir_emit_dots(file, ctx))
1023 mutex_lock(&kernfs_mutex);
1025 if (kernfs_ns_enabled(parent))
1026 ns = kernfs_info(dentry->d_sb)->ns;
1028 for (pos = kernfs_dir_pos(ns, parent, ctx->pos, pos);
1030 pos = kernfs_dir_next_pos(ns, parent, ctx->pos, pos)) {
1031 const char *name = pos->name;
1032 unsigned int type = dt_type(pos);
1033 int len = strlen(name);
1034 ino_t ino = pos->ino;
1036 ctx->pos = pos->hash;
1037 file->private_data = pos;
1040 mutex_unlock(&kernfs_mutex);
1041 if (!dir_emit(ctx, name, len, ino, type))
1043 mutex_lock(&kernfs_mutex);
1045 mutex_unlock(&kernfs_mutex);
1046 file->private_data = NULL;
1051 static loff_t kernfs_dir_fop_llseek(struct file *file, loff_t offset,
1054 struct inode *inode = file_inode(file);
1057 mutex_lock(&inode->i_mutex);
1058 ret = generic_file_llseek(file, offset, whence);
1059 mutex_unlock(&inode->i_mutex);
1064 const struct file_operations kernfs_dir_fops = {
1065 .read = generic_read_dir,
1066 .iterate = kernfs_fop_readdir,
1067 .release = kernfs_dir_fop_release,
1068 .llseek = kernfs_dir_fop_llseek,