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_active(struct kernfs_node *kn)
27 lockdep_assert_held(&kernfs_mutex);
28 return atomic_read(&kn->active) >= 0;
31 static bool kernfs_lockdep(struct kernfs_node *kn)
33 #ifdef CONFIG_DEBUG_LOCK_ALLOC
34 return kn->flags & KERNFS_LOCKDEP;
42 * @name: Null terminated string to hash
43 * @ns: Namespace tag to hash
45 * Returns 31 bit hash of ns + name (so it fits in an off_t )
47 static unsigned int kernfs_name_hash(const char *name, const void *ns)
49 unsigned long hash = init_name_hash();
50 unsigned int len = strlen(name);
52 hash = partial_name_hash(*name++, hash);
53 hash = (end_name_hash(hash) ^ hash_ptr((void *)ns, 31));
55 /* Reserve hash numbers 0, 1 and INT_MAX for magic directory entries */
63 static int kernfs_name_compare(unsigned int hash, const char *name,
64 const void *ns, const struct kernfs_node *kn)
67 return hash - kn->hash;
70 return strcmp(name, kn->name);
73 static int kernfs_sd_compare(const struct kernfs_node *left,
74 const struct kernfs_node *right)
76 return kernfs_name_compare(left->hash, left->name, left->ns, right);
80 * kernfs_link_sibling - link kernfs_node into sibling rbtree
81 * @kn: kernfs_node of interest
83 * Link @kn into its sibling rbtree which starts from
84 * @kn->parent->dir.children.
87 * mutex_lock(kernfs_mutex)
90 * 0 on susccess -EEXIST on failure.
92 static int kernfs_link_sibling(struct kernfs_node *kn)
94 struct rb_node **node = &kn->parent->dir.children.rb_node;
95 struct rb_node *parent = NULL;
97 if (kernfs_type(kn) == KERNFS_DIR)
98 kn->parent->dir.subdirs++;
101 struct kernfs_node *pos;
104 pos = rb_to_kn(*node);
106 result = kernfs_sd_compare(kn, pos);
108 node = &pos->rb.rb_left;
110 node = &pos->rb.rb_right;
114 /* add new node and rebalance the tree */
115 rb_link_node(&kn->rb, parent, node);
116 rb_insert_color(&kn->rb, &kn->parent->dir.children);
121 * kernfs_unlink_sibling - unlink kernfs_node from sibling rbtree
122 * @kn: kernfs_node of interest
124 * Try to unlink @kn from its sibling rbtree which starts from
125 * kn->parent->dir.children. Returns %true if @kn was actually
126 * removed, %false if @kn wasn't on the rbtree.
129 * mutex_lock(kernfs_mutex)
131 static bool kernfs_unlink_sibling(struct kernfs_node *kn)
133 if (RB_EMPTY_NODE(&kn->rb))
136 if (kernfs_type(kn) == KERNFS_DIR)
137 kn->parent->dir.subdirs--;
139 rb_erase(&kn->rb, &kn->parent->dir.children);
140 RB_CLEAR_NODE(&kn->rb);
145 * kernfs_get_active - get an active reference to kernfs_node
146 * @kn: kernfs_node to get an active reference to
148 * Get an active reference of @kn. This function is noop if @kn
152 * Pointer to @kn on success, NULL on failure.
154 struct kernfs_node *kernfs_get_active(struct kernfs_node *kn)
159 if (!atomic_inc_unless_negative(&kn->active))
162 if (kernfs_lockdep(kn))
163 rwsem_acquire_read(&kn->dep_map, 0, 1, _RET_IP_);
168 * kernfs_put_active - put an active reference to kernfs_node
169 * @kn: kernfs_node to put an active reference to
171 * Put an active reference to @kn. This function is noop if @kn
174 void kernfs_put_active(struct kernfs_node *kn)
176 struct kernfs_root *root = kernfs_root(kn);
182 if (kernfs_lockdep(kn))
183 rwsem_release(&kn->dep_map, 1, _RET_IP_);
184 v = atomic_dec_return(&kn->active);
185 if (likely(v != KN_DEACTIVATED_BIAS))
188 wake_up_all(&root->deactivate_waitq);
192 * kernfs_drain - drain kernfs_node
193 * @kn: kernfs_node to drain
195 * Drain existing usages and nuke all existing mmaps of @kn. Mutiple
196 * removers may invoke this function concurrently on @kn and all will
197 * return after draining is complete.
199 static void kernfs_drain(struct kernfs_node *kn)
200 __releases(&kernfs_mutex) __acquires(&kernfs_mutex)
202 struct kernfs_root *root = kernfs_root(kn);
204 lockdep_assert_held(&kernfs_mutex);
205 WARN_ON_ONCE(kernfs_active(kn));
207 mutex_unlock(&kernfs_mutex);
209 if (kernfs_lockdep(kn)) {
210 rwsem_acquire(&kn->dep_map, 0, 0, _RET_IP_);
211 if (atomic_read(&kn->active) != KN_DEACTIVATED_BIAS)
212 lock_contended(&kn->dep_map, _RET_IP_);
215 /* but everyone should wait for draining */
216 wait_event(root->deactivate_waitq,
217 atomic_read(&kn->active) == KN_DEACTIVATED_BIAS);
219 if (kernfs_lockdep(kn)) {
220 lock_acquired(&kn->dep_map, _RET_IP_);
221 rwsem_release(&kn->dep_map, 1, _RET_IP_);
224 kernfs_unmap_bin_file(kn);
226 mutex_lock(&kernfs_mutex);
230 * kernfs_get - get a reference count on a kernfs_node
231 * @kn: the target kernfs_node
233 void kernfs_get(struct kernfs_node *kn)
236 WARN_ON(!atomic_read(&kn->count));
237 atomic_inc(&kn->count);
240 EXPORT_SYMBOL_GPL(kernfs_get);
243 * kernfs_put - put a reference count on a kernfs_node
244 * @kn: the target kernfs_node
246 * Put a reference count of @kn and destroy it if it reached zero.
248 void kernfs_put(struct kernfs_node *kn)
250 struct kernfs_node *parent;
251 struct kernfs_root *root;
253 if (!kn || !atomic_dec_and_test(&kn->count))
255 root = kernfs_root(kn);
258 * Moving/renaming is always done while holding reference.
259 * kn->parent won't change beneath us.
263 WARN_ONCE(atomic_read(&kn->active) != KN_DEACTIVATED_BIAS,
264 "kernfs_put: %s/%s: released with incorrect active_ref %d\n",
265 parent ? parent->name : "", kn->name, atomic_read(&kn->active));
267 if (kernfs_type(kn) == KERNFS_LINK)
268 kernfs_put(kn->symlink.target_kn);
269 if (!(kn->flags & KERNFS_STATIC_NAME))
272 if (kn->iattr->ia_secdata)
273 security_release_secctx(kn->iattr->ia_secdata,
274 kn->iattr->ia_secdata_len);
275 simple_xattrs_free(&kn->iattr->xattrs);
278 ida_simple_remove(&root->ino_ida, kn->ino);
279 kmem_cache_free(kernfs_node_cache, kn);
283 if (atomic_dec_and_test(&kn->count))
286 /* just released the root kn, free @root too */
287 ida_destroy(&root->ino_ida);
291 EXPORT_SYMBOL_GPL(kernfs_put);
293 static int kernfs_dop_revalidate(struct dentry *dentry, unsigned int flags)
295 struct kernfs_node *kn;
297 if (flags & LOOKUP_RCU)
300 /* Always perform fresh lookup for negatives */
301 if (!dentry->d_inode)
302 goto out_bad_unlocked;
304 kn = dentry->d_fsdata;
305 mutex_lock(&kernfs_mutex);
307 /* The kernfs node has been deactivated */
308 if (!kernfs_active(kn))
311 /* The kernfs node has been moved? */
312 if (dentry->d_parent->d_fsdata != kn->parent)
315 /* The kernfs node has been renamed */
316 if (strcmp(dentry->d_name.name, kn->name) != 0)
319 /* The kernfs node has been moved to a different namespace */
320 if (kn->parent && kernfs_ns_enabled(kn->parent) &&
321 kernfs_info(dentry->d_sb)->ns != kn->ns)
324 mutex_unlock(&kernfs_mutex);
328 mutex_unlock(&kernfs_mutex);
331 * @dentry doesn't match the underlying kernfs node, drop the
332 * dentry and force lookup. If we have submounts we must allow the
333 * vfs caches to lie about the state of the filesystem to prevent
334 * leaks and other nasty things, so use check_submounts_and_drop()
335 * instead of d_drop().
337 if (check_submounts_and_drop(dentry) != 0)
343 static void kernfs_dop_release(struct dentry *dentry)
345 kernfs_put(dentry->d_fsdata);
348 const struct dentry_operations kernfs_dops = {
349 .d_revalidate = kernfs_dop_revalidate,
350 .d_release = kernfs_dop_release,
353 static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root,
354 const char *name, umode_t mode,
357 char *dup_name = NULL;
358 struct kernfs_node *kn;
361 if (!(flags & KERNFS_STATIC_NAME)) {
362 name = dup_name = kstrdup(name, GFP_KERNEL);
367 kn = kmem_cache_zalloc(kernfs_node_cache, GFP_KERNEL);
371 ret = ida_simple_get(&root->ino_ida, 1, 0, GFP_KERNEL);
376 atomic_set(&kn->count, 1);
377 atomic_set(&kn->active, KN_DEACTIVATED_BIAS);
378 RB_CLEAR_NODE(&kn->rb);
387 kmem_cache_free(kernfs_node_cache, kn);
393 struct kernfs_node *kernfs_new_node(struct kernfs_node *parent,
394 const char *name, umode_t mode,
397 struct kernfs_node *kn;
399 kn = __kernfs_new_node(kernfs_root(parent), name, mode, flags);
408 * kernfs_add_one - add kernfs_node to parent without warning
409 * @kn: kernfs_node to be added
411 * The caller must already have initialized @kn->parent. This
412 * function increments nlink of the parent's inode if @kn is a
413 * directory and link into the children list of the parent.
416 * 0 on success, -EEXIST if entry with the given name already
419 int kernfs_add_one(struct kernfs_node *kn)
421 struct kernfs_node *parent = kn->parent;
422 struct kernfs_iattrs *ps_iattr;
426 mutex_lock(&kernfs_mutex);
429 has_ns = kernfs_ns_enabled(parent);
430 if (WARN(has_ns != (bool)kn->ns, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n",
431 has_ns ? "required" : "invalid", parent->name, kn->name))
434 if (kernfs_type(parent) != KERNFS_DIR)
438 if (!kernfs_active(parent))
441 kn->hash = kernfs_name_hash(kn->name, kn->ns);
443 ret = kernfs_link_sibling(kn);
447 /* Update timestamps on the parent */
448 ps_iattr = parent->iattr;
450 struct iattr *ps_iattrs = &ps_iattr->ia_iattr;
451 ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME;
454 /* Mark the entry added into directory tree */
455 atomic_sub(KN_DEACTIVATED_BIAS, &kn->active);
458 mutex_unlock(&kernfs_mutex);
463 * kernfs_find_ns - find kernfs_node with the given name
464 * @parent: kernfs_node to search under
465 * @name: name to look for
466 * @ns: the namespace tag to use
468 * Look for kernfs_node with name @name under @parent. Returns pointer to
469 * the found kernfs_node on success, %NULL on failure.
471 static struct kernfs_node *kernfs_find_ns(struct kernfs_node *parent,
472 const unsigned char *name,
475 struct rb_node *node = parent->dir.children.rb_node;
476 bool has_ns = kernfs_ns_enabled(parent);
479 lockdep_assert_held(&kernfs_mutex);
481 if (has_ns != (bool)ns) {
482 WARN(1, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n",
483 has_ns ? "required" : "invalid", parent->name, name);
487 hash = kernfs_name_hash(name, ns);
489 struct kernfs_node *kn;
493 result = kernfs_name_compare(hash, name, ns, kn);
495 node = node->rb_left;
497 node = node->rb_right;
505 * kernfs_find_and_get_ns - find and get kernfs_node with the given name
506 * @parent: kernfs_node to search under
507 * @name: name to look for
508 * @ns: the namespace tag to use
510 * Look for kernfs_node with name @name under @parent and get a reference
511 * if found. This function may sleep and returns pointer to the found
512 * kernfs_node on success, %NULL on failure.
514 struct kernfs_node *kernfs_find_and_get_ns(struct kernfs_node *parent,
515 const char *name, const void *ns)
517 struct kernfs_node *kn;
519 mutex_lock(&kernfs_mutex);
520 kn = kernfs_find_ns(parent, name, ns);
522 mutex_unlock(&kernfs_mutex);
526 EXPORT_SYMBOL_GPL(kernfs_find_and_get_ns);
529 * kernfs_create_root - create a new kernfs hierarchy
530 * @kdops: optional directory syscall operations for the hierarchy
531 * @priv: opaque data associated with the new directory
533 * Returns the root of the new hierarchy on success, ERR_PTR() value on
536 struct kernfs_root *kernfs_create_root(struct kernfs_dir_ops *kdops, void *priv)
538 struct kernfs_root *root;
539 struct kernfs_node *kn;
541 root = kzalloc(sizeof(*root), GFP_KERNEL);
543 return ERR_PTR(-ENOMEM);
545 ida_init(&root->ino_ida);
547 kn = __kernfs_new_node(root, "", S_IFDIR | S_IRUGO | S_IXUGO,
550 ida_destroy(&root->ino_ida);
552 return ERR_PTR(-ENOMEM);
555 atomic_sub(KN_DEACTIVATED_BIAS, &kn->active);
559 root->dir_ops = kdops;
561 init_waitqueue_head(&root->deactivate_waitq);
567 * kernfs_destroy_root - destroy a kernfs hierarchy
568 * @root: root of the hierarchy to destroy
570 * Destroy the hierarchy anchored at @root by removing all existing
571 * directories and destroying @root.
573 void kernfs_destroy_root(struct kernfs_root *root)
575 kernfs_remove(root->kn); /* will also free @root */
579 * kernfs_create_dir_ns - create a directory
580 * @parent: parent in which to create a new directory
581 * @name: name of the new directory
582 * @mode: mode of the new directory
583 * @priv: opaque data associated with the new directory
584 * @ns: optional namespace tag of the directory
586 * Returns the created node on success, ERR_PTR() value on failure.
588 struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent,
589 const char *name, umode_t mode,
590 void *priv, const void *ns)
592 struct kernfs_node *kn;
596 kn = kernfs_new_node(parent, name, mode | S_IFDIR, KERNFS_DIR);
598 return ERR_PTR(-ENOMEM);
600 kn->dir.root = parent->dir.root;
605 rc = kernfs_add_one(kn);
613 static struct dentry *kernfs_iop_lookup(struct inode *dir,
614 struct dentry *dentry,
618 struct kernfs_node *parent = dentry->d_parent->d_fsdata;
619 struct kernfs_node *kn;
621 const void *ns = NULL;
623 mutex_lock(&kernfs_mutex);
625 if (kernfs_ns_enabled(parent))
626 ns = kernfs_info(dir->i_sb)->ns;
628 kn = kernfs_find_ns(parent, dentry->d_name.name, ns);
636 dentry->d_fsdata = kn;
638 /* attach dentry and inode */
639 inode = kernfs_get_inode(dir->i_sb, kn);
641 ret = ERR_PTR(-ENOMEM);
645 /* instantiate and hash dentry */
646 ret = d_materialise_unique(dentry, inode);
648 mutex_unlock(&kernfs_mutex);
652 static int kernfs_iop_mkdir(struct inode *dir, struct dentry *dentry,
655 struct kernfs_node *parent = dir->i_private;
656 struct kernfs_dir_ops *kdops = kernfs_root(parent)->dir_ops;
658 if (!kdops || !kdops->mkdir)
661 return kdops->mkdir(parent, dentry->d_name.name, mode);
664 static int kernfs_iop_rmdir(struct inode *dir, struct dentry *dentry)
666 struct kernfs_node *kn = dentry->d_fsdata;
667 struct kernfs_dir_ops *kdops = kernfs_root(kn)->dir_ops;
669 if (!kdops || !kdops->rmdir)
672 return kdops->rmdir(kn);
675 static int kernfs_iop_rename(struct inode *old_dir, struct dentry *old_dentry,
676 struct inode *new_dir, struct dentry *new_dentry)
678 struct kernfs_node *kn = old_dentry->d_fsdata;
679 struct kernfs_node *new_parent = new_dir->i_private;
680 struct kernfs_dir_ops *kdops = kernfs_root(kn)->dir_ops;
682 if (!kdops || !kdops->rename)
685 return kdops->rename(kn, new_parent, new_dentry->d_name.name);
688 const struct inode_operations kernfs_dir_iops = {
689 .lookup = kernfs_iop_lookup,
690 .permission = kernfs_iop_permission,
691 .setattr = kernfs_iop_setattr,
692 .getattr = kernfs_iop_getattr,
693 .setxattr = kernfs_iop_setxattr,
694 .removexattr = kernfs_iop_removexattr,
695 .getxattr = kernfs_iop_getxattr,
696 .listxattr = kernfs_iop_listxattr,
698 .mkdir = kernfs_iop_mkdir,
699 .rmdir = kernfs_iop_rmdir,
700 .rename = kernfs_iop_rename,
703 static struct kernfs_node *kernfs_leftmost_descendant(struct kernfs_node *pos)
705 struct kernfs_node *last;
712 if (kernfs_type(pos) != KERNFS_DIR)
715 rbn = rb_first(&pos->dir.children);
726 * kernfs_next_descendant_post - find the next descendant for post-order walk
727 * @pos: the current position (%NULL to initiate traversal)
728 * @root: kernfs_node whose descendants to walk
730 * Find the next descendant to visit for post-order traversal of @root's
731 * descendants. @root is included in the iteration and the last node to be
734 static struct kernfs_node *kernfs_next_descendant_post(struct kernfs_node *pos,
735 struct kernfs_node *root)
739 lockdep_assert_held(&kernfs_mutex);
741 /* if first iteration, visit leftmost descendant which may be root */
743 return kernfs_leftmost_descendant(root);
745 /* if we visited @root, we're done */
749 /* if there's an unvisited sibling, visit its leftmost descendant */
750 rbn = rb_next(&pos->rb);
752 return kernfs_leftmost_descendant(rb_to_kn(rbn));
754 /* no sibling left, visit parent */
758 static void __kernfs_remove(struct kernfs_node *kn)
760 struct kernfs_node *pos;
762 lockdep_assert_held(&kernfs_mutex);
767 pr_debug("kernfs %s: removing\n", kn->name);
769 /* prevent any new usage under @kn by deactivating all nodes */
771 while ((pos = kernfs_next_descendant_post(pos, kn)))
772 if (kernfs_active(pos))
773 atomic_add(KN_DEACTIVATED_BIAS, &pos->active);
775 /* deactivate and unlink the subtree node-by-node */
777 pos = kernfs_leftmost_descendant(kn);
780 * kernfs_drain() drops kernfs_mutex temporarily and @pos's
781 * base ref could have been put by someone else by the time
782 * the function returns. Make sure it doesn't go away
790 * kernfs_unlink_sibling() succeeds once per node. Use it
791 * to decide who's responsible for cleanups.
793 if (!pos->parent || kernfs_unlink_sibling(pos)) {
794 struct kernfs_iattrs *ps_iattr =
795 pos->parent ? pos->parent->iattr : NULL;
797 /* update timestamps on the parent */
799 ps_iattr->ia_iattr.ia_ctime = CURRENT_TIME;
800 ps_iattr->ia_iattr.ia_mtime = CURRENT_TIME;
811 * kernfs_remove - remove a kernfs_node recursively
812 * @kn: the kernfs_node to remove
814 * Remove @kn along with all its subdirectories and files.
816 void kernfs_remove(struct kernfs_node *kn)
818 mutex_lock(&kernfs_mutex);
820 mutex_unlock(&kernfs_mutex);
824 * kernfs_remove_by_name_ns - find a kernfs_node by name and remove it
825 * @parent: parent of the target
826 * @name: name of the kernfs_node to remove
827 * @ns: namespace tag of the kernfs_node to remove
829 * Look for the kernfs_node with @name and @ns under @parent and remove it.
830 * Returns 0 on success, -ENOENT if such entry doesn't exist.
832 int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name,
835 struct kernfs_node *kn;
838 WARN(1, KERN_WARNING "kernfs: can not remove '%s', no directory\n",
843 mutex_lock(&kernfs_mutex);
845 kn = kernfs_find_ns(parent, name, ns);
849 mutex_unlock(&kernfs_mutex);
858 * kernfs_rename_ns - move and rename a kernfs_node
860 * @new_parent: new parent to put @sd under
861 * @new_name: new name
862 * @new_ns: new namespace tag
864 int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent,
865 const char *new_name, const void *new_ns)
869 mutex_lock(&kernfs_mutex);
872 if (!kernfs_active(kn) || !kernfs_active(new_parent))
876 if ((kn->parent == new_parent) && (kn->ns == new_ns) &&
877 (strcmp(kn->name, new_name) == 0))
878 goto out; /* nothing to rename */
881 if (kernfs_find_ns(new_parent, new_name, new_ns))
884 /* rename kernfs_node */
885 if (strcmp(kn->name, new_name) != 0) {
887 new_name = kstrdup(new_name, GFP_KERNEL);
891 if (kn->flags & KERNFS_STATIC_NAME)
892 kn->flags &= ~KERNFS_STATIC_NAME;
900 * Move to the appropriate place in the appropriate directories rbtree.
902 kernfs_unlink_sibling(kn);
903 kernfs_get(new_parent);
904 kernfs_put(kn->parent);
906 kn->hash = kernfs_name_hash(kn->name, kn->ns);
907 kn->parent = new_parent;
908 kernfs_link_sibling(kn);
912 mutex_unlock(&kernfs_mutex);
916 /* Relationship between s_mode and the DT_xxx types */
917 static inline unsigned char dt_type(struct kernfs_node *kn)
919 return (kn->mode >> 12) & 15;
922 static int kernfs_dir_fop_release(struct inode *inode, struct file *filp)
924 kernfs_put(filp->private_data);
928 static struct kernfs_node *kernfs_dir_pos(const void *ns,
929 struct kernfs_node *parent, loff_t hash, struct kernfs_node *pos)
932 int valid = kernfs_active(pos) &&
933 pos->parent == parent && hash == pos->hash;
938 if (!pos && (hash > 1) && (hash < INT_MAX)) {
939 struct rb_node *node = parent->dir.children.rb_node;
941 pos = rb_to_kn(node);
943 if (hash < pos->hash)
944 node = node->rb_left;
945 else if (hash > pos->hash)
946 node = node->rb_right;
951 /* Skip over entries in the wrong namespace */
952 while (pos && pos->ns != ns) {
953 struct rb_node *node = rb_next(&pos->rb);
957 pos = rb_to_kn(node);
962 static struct kernfs_node *kernfs_dir_next_pos(const void *ns,
963 struct kernfs_node *parent, ino_t ino, struct kernfs_node *pos)
965 pos = kernfs_dir_pos(ns, parent, ino, pos);
968 struct rb_node *node = rb_next(&pos->rb);
972 pos = rb_to_kn(node);
973 } while (pos && pos->ns != ns);
977 static int kernfs_fop_readdir(struct file *file, struct dir_context *ctx)
979 struct dentry *dentry = file->f_path.dentry;
980 struct kernfs_node *parent = dentry->d_fsdata;
981 struct kernfs_node *pos = file->private_data;
982 const void *ns = NULL;
984 if (!dir_emit_dots(file, ctx))
986 mutex_lock(&kernfs_mutex);
988 if (kernfs_ns_enabled(parent))
989 ns = kernfs_info(dentry->d_sb)->ns;
991 for (pos = kernfs_dir_pos(ns, parent, ctx->pos, pos);
993 pos = kernfs_dir_next_pos(ns, parent, ctx->pos, pos)) {
994 const char *name = pos->name;
995 unsigned int type = dt_type(pos);
996 int len = strlen(name);
997 ino_t ino = pos->ino;
999 ctx->pos = pos->hash;
1000 file->private_data = pos;
1003 mutex_unlock(&kernfs_mutex);
1004 if (!dir_emit(ctx, name, len, ino, type))
1006 mutex_lock(&kernfs_mutex);
1008 mutex_unlock(&kernfs_mutex);
1009 file->private_data = NULL;
1014 static loff_t kernfs_dir_fop_llseek(struct file *file, loff_t offset,
1017 struct inode *inode = file_inode(file);
1020 mutex_lock(&inode->i_mutex);
1021 ret = generic_file_llseek(file, offset, whence);
1022 mutex_unlock(&inode->i_mutex);
1027 const struct file_operations kernfs_dir_fops = {
1028 .read = generic_read_dir,
1029 .iterate = kernfs_fop_readdir,
1030 .release = kernfs_dir_fop_release,
1031 .llseek = kernfs_dir_fop_llseek,