blob: 5cf137b63db952c2d496264c33533da40705ea28 [file] [log] [blame]
Tejun Heob8441ed2013-11-24 09:54:58 -05001/*
2 * fs/kernfs/dir.c - kernfs directory implementation
3 *
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>
7 *
8 * This file is released under the GPLv2.
9 */
Tejun Heofd7b9f72013-11-28 14:54:33 -050010
Tejun Heoabd54f02014-02-03 14:02:55 -050011#include <linux/sched.h>
Tejun Heofd7b9f72013-11-28 14:54:33 -050012#include <linux/fs.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>
18
19#include "kernfs-internal.h"
20
Tejun Heoa797bfc2013-12-11 14:11:57 -050021DEFINE_MUTEX(kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -050022
Tejun Heoadc5e8b2013-12-11 14:11:54 -050023#define rb_to_kn(X) rb_entry((X), struct kernfs_node, rb)
Tejun Heofd7b9f72013-11-28 14:54:33 -050024
Tejun Heo182fd642014-02-03 14:02:59 -050025static bool kernfs_lockdep(struct kernfs_node *kn)
26{
27#ifdef CONFIG_DEBUG_LOCK_ALLOC
28 return kn->flags & KERNFS_LOCKDEP;
29#else
30 return false;
31#endif
32}
33
Tejun Heofd7b9f72013-11-28 14:54:33 -050034/**
Tejun Heoc637b8a2013-12-11 14:11:58 -050035 * kernfs_name_hash
Tejun Heofd7b9f72013-11-28 14:54:33 -050036 * @name: Null terminated string to hash
37 * @ns: Namespace tag to hash
38 *
39 * Returns 31 bit hash of ns + name (so it fits in an off_t )
40 */
Tejun Heoc637b8a2013-12-11 14:11:58 -050041static unsigned int kernfs_name_hash(const char *name, const void *ns)
Tejun Heofd7b9f72013-11-28 14:54:33 -050042{
43 unsigned long hash = init_name_hash();
44 unsigned int len = strlen(name);
45 while (len--)
46 hash = partial_name_hash(*name++, hash);
47 hash = (end_name_hash(hash) ^ hash_ptr((void *)ns, 31));
48 hash &= 0x7fffffffU;
49 /* Reserve hash numbers 0, 1 and INT_MAX for magic directory entries */
50 if (hash < 1)
51 hash += 2;
52 if (hash >= INT_MAX)
53 hash = INT_MAX - 1;
54 return hash;
55}
56
Tejun Heoc637b8a2013-12-11 14:11:58 -050057static int kernfs_name_compare(unsigned int hash, const char *name,
58 const void *ns, const struct kernfs_node *kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -050059{
Tejun Heoadc5e8b2013-12-11 14:11:54 -050060 if (hash != kn->hash)
61 return hash - kn->hash;
62 if (ns != kn->ns)
63 return ns - kn->ns;
64 return strcmp(name, kn->name);
Tejun Heofd7b9f72013-11-28 14:54:33 -050065}
66
Tejun Heoc637b8a2013-12-11 14:11:58 -050067static int kernfs_sd_compare(const struct kernfs_node *left,
68 const struct kernfs_node *right)
Tejun Heofd7b9f72013-11-28 14:54:33 -050069{
Tejun Heoc637b8a2013-12-11 14:11:58 -050070 return kernfs_name_compare(left->hash, left->name, left->ns, right);
Tejun Heofd7b9f72013-11-28 14:54:33 -050071}
72
73/**
Tejun Heoc637b8a2013-12-11 14:11:58 -050074 * kernfs_link_sibling - link kernfs_node into sibling rbtree
Tejun Heo324a56e2013-12-11 14:11:53 -050075 * @kn: kernfs_node of interest
Tejun Heofd7b9f72013-11-28 14:54:33 -050076 *
Tejun Heo324a56e2013-12-11 14:11:53 -050077 * Link @kn into its sibling rbtree which starts from
Tejun Heoadc5e8b2013-12-11 14:11:54 -050078 * @kn->parent->dir.children.
Tejun Heofd7b9f72013-11-28 14:54:33 -050079 *
80 * Locking:
Tejun Heoa797bfc2013-12-11 14:11:57 -050081 * mutex_lock(kernfs_mutex)
Tejun Heofd7b9f72013-11-28 14:54:33 -050082 *
83 * RETURNS:
84 * 0 on susccess -EEXIST on failure.
85 */
Tejun Heoc637b8a2013-12-11 14:11:58 -050086static int kernfs_link_sibling(struct kernfs_node *kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -050087{
Tejun Heoadc5e8b2013-12-11 14:11:54 -050088 struct rb_node **node = &kn->parent->dir.children.rb_node;
Tejun Heofd7b9f72013-11-28 14:54:33 -050089 struct rb_node *parent = NULL;
90
Tejun Heodf23fc32013-12-11 14:11:56 -050091 if (kernfs_type(kn) == KERNFS_DIR)
Tejun Heoadc5e8b2013-12-11 14:11:54 -050092 kn->parent->dir.subdirs++;
Tejun Heofd7b9f72013-11-28 14:54:33 -050093
94 while (*node) {
Tejun Heo324a56e2013-12-11 14:11:53 -050095 struct kernfs_node *pos;
Tejun Heofd7b9f72013-11-28 14:54:33 -050096 int result;
97
Tejun Heo324a56e2013-12-11 14:11:53 -050098 pos = rb_to_kn(*node);
Tejun Heofd7b9f72013-11-28 14:54:33 -050099 parent = *node;
Tejun Heoc637b8a2013-12-11 14:11:58 -0500100 result = kernfs_sd_compare(kn, pos);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500101 if (result < 0)
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500102 node = &pos->rb.rb_left;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500103 else if (result > 0)
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500104 node = &pos->rb.rb_right;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500105 else
106 return -EEXIST;
107 }
108 /* add new node and rebalance the tree */
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500109 rb_link_node(&kn->rb, parent, node);
110 rb_insert_color(&kn->rb, &kn->parent->dir.children);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500111 return 0;
112}
113
114/**
Tejun Heoc637b8a2013-12-11 14:11:58 -0500115 * kernfs_unlink_sibling - unlink kernfs_node from sibling rbtree
Tejun Heo324a56e2013-12-11 14:11:53 -0500116 * @kn: kernfs_node of interest
Tejun Heofd7b9f72013-11-28 14:54:33 -0500117 *
Tejun Heo35beab02014-02-03 14:02:56 -0500118 * Try to unlink @kn from its sibling rbtree which starts from
119 * kn->parent->dir.children. Returns %true if @kn was actually
120 * removed, %false if @kn wasn't on the rbtree.
Tejun Heofd7b9f72013-11-28 14:54:33 -0500121 *
122 * Locking:
Tejun Heoa797bfc2013-12-11 14:11:57 -0500123 * mutex_lock(kernfs_mutex)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500124 */
Tejun Heo35beab02014-02-03 14:02:56 -0500125static bool kernfs_unlink_sibling(struct kernfs_node *kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500126{
Tejun Heo35beab02014-02-03 14:02:56 -0500127 if (RB_EMPTY_NODE(&kn->rb))
128 return false;
129
Tejun Heodf23fc32013-12-11 14:11:56 -0500130 if (kernfs_type(kn) == KERNFS_DIR)
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500131 kn->parent->dir.subdirs--;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500132
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500133 rb_erase(&kn->rb, &kn->parent->dir.children);
Tejun Heo35beab02014-02-03 14:02:56 -0500134 RB_CLEAR_NODE(&kn->rb);
135 return true;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500136}
137
138/**
Tejun Heoc637b8a2013-12-11 14:11:58 -0500139 * kernfs_get_active - get an active reference to kernfs_node
Tejun Heo324a56e2013-12-11 14:11:53 -0500140 * @kn: kernfs_node to get an active reference to
Tejun Heofd7b9f72013-11-28 14:54:33 -0500141 *
Tejun Heo324a56e2013-12-11 14:11:53 -0500142 * Get an active reference of @kn. This function is noop if @kn
Tejun Heofd7b9f72013-11-28 14:54:33 -0500143 * is NULL.
144 *
145 * RETURNS:
Tejun Heo324a56e2013-12-11 14:11:53 -0500146 * Pointer to @kn on success, NULL on failure.
Tejun Heofd7b9f72013-11-28 14:54:33 -0500147 */
Tejun Heoc637b8a2013-12-11 14:11:58 -0500148struct kernfs_node *kernfs_get_active(struct kernfs_node *kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500149{
Tejun Heo324a56e2013-12-11 14:11:53 -0500150 if (unlikely(!kn))
Tejun Heofd7b9f72013-11-28 14:54:33 -0500151 return NULL;
152
Greg Kroah-Hartmanf4b3e632014-01-13 14:13:39 -0800153 if (!atomic_inc_unless_negative(&kn->active))
154 return NULL;
155
Tejun Heo182fd642014-02-03 14:02:59 -0500156 if (kernfs_lockdep(kn))
Tejun Heo324a56e2013-12-11 14:11:53 -0500157 rwsem_acquire_read(&kn->dep_map, 0, 1, _RET_IP_);
Greg Kroah-Hartmanf4b3e632014-01-13 14:13:39 -0800158 return kn;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500159}
160
161/**
Tejun Heoc637b8a2013-12-11 14:11:58 -0500162 * kernfs_put_active - put an active reference to kernfs_node
Tejun Heo324a56e2013-12-11 14:11:53 -0500163 * @kn: kernfs_node to put an active reference to
Tejun Heofd7b9f72013-11-28 14:54:33 -0500164 *
Tejun Heo324a56e2013-12-11 14:11:53 -0500165 * Put an active reference to @kn. This function is noop if @kn
Tejun Heofd7b9f72013-11-28 14:54:33 -0500166 * is NULL.
167 */
Tejun Heoc637b8a2013-12-11 14:11:58 -0500168void kernfs_put_active(struct kernfs_node *kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500169{
Tejun Heoabd54f02014-02-03 14:02:55 -0500170 struct kernfs_root *root = kernfs_root(kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500171 int v;
172
Tejun Heo324a56e2013-12-11 14:11:53 -0500173 if (unlikely(!kn))
Tejun Heofd7b9f72013-11-28 14:54:33 -0500174 return;
175
Tejun Heo182fd642014-02-03 14:02:59 -0500176 if (kernfs_lockdep(kn))
Tejun Heo324a56e2013-12-11 14:11:53 -0500177 rwsem_release(&kn->dep_map, 1, _RET_IP_);
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500178 v = atomic_dec_return(&kn->active);
Tejun Heodf23fc32013-12-11 14:11:56 -0500179 if (likely(v != KN_DEACTIVATED_BIAS))
Tejun Heofd7b9f72013-11-28 14:54:33 -0500180 return;
181
Tejun Heoabd54f02014-02-03 14:02:55 -0500182 wake_up_all(&root->deactivate_waitq);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500183}
184
185/**
Greg Kroah-Hartman798c75a2014-01-13 14:36:03 -0800186 * kernfs_deactivate - deactivate kernfs_node
187 * @kn: kernfs_node to deactivate
Tejun Heofd7b9f72013-11-28 14:54:33 -0500188 *
Tejun Heoccf02aa2014-02-03 14:02:57 -0500189 * Deny new active references, drain existing ones and nuke all
190 * existing mmaps. Mutiple removers may invoke this function
191 * concurrently on @kn and all will return after deactivation and
192 * draining are complete.
Tejun Heofd7b9f72013-11-28 14:54:33 -0500193 */
Greg Kroah-Hartman798c75a2014-01-13 14:36:03 -0800194static void kernfs_deactivate(struct kernfs_node *kn)
Tejun Heo35beab02014-02-03 14:02:56 -0500195 __releases(&kernfs_mutex) __acquires(&kernfs_mutex)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500196{
Tejun Heoabd54f02014-02-03 14:02:55 -0500197 struct kernfs_root *root = kernfs_root(kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500198
Tejun Heo35beab02014-02-03 14:02:56 -0500199 lockdep_assert_held(&kernfs_mutex);
Greg Kroah-Hartman798c75a2014-01-13 14:36:03 -0800200 BUG_ON(!(kn->flags & KERNFS_REMOVED));
201
Tejun Heo35beab02014-02-03 14:02:56 -0500202 /* only the first invocation on @kn should deactivate it */
203 if (atomic_read(&kn->active) >= 0)
204 atomic_add(KN_DEACTIVATED_BIAS, &kn->active);
205
206 mutex_unlock(&kernfs_mutex);
207
Tejun Heo182fd642014-02-03 14:02:59 -0500208 if (kernfs_lockdep(kn)) {
Tejun Heoa6607932014-02-03 14:02:54 -0500209 rwsem_acquire(&kn->dep_map, 0, 0, _RET_IP_);
Tejun Heo35beab02014-02-03 14:02:56 -0500210 if (atomic_read(&kn->active) != KN_DEACTIVATED_BIAS)
211 lock_contended(&kn->dep_map, _RET_IP_);
212 }
Greg Kroah-Hartman08901472014-01-13 14:39:52 -0800213
Tejun Heo35beab02014-02-03 14:02:56 -0500214 /* but everyone should wait for draining */
Tejun Heoabd54f02014-02-03 14:02:55 -0500215 wait_event(root->deactivate_waitq,
216 atomic_read(&kn->active) == KN_DEACTIVATED_BIAS);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500217
Tejun Heo182fd642014-02-03 14:02:59 -0500218 if (kernfs_lockdep(kn)) {
Tejun Heoa6607932014-02-03 14:02:54 -0500219 lock_acquired(&kn->dep_map, _RET_IP_);
220 rwsem_release(&kn->dep_map, 1, _RET_IP_);
221 }
Tejun Heo35beab02014-02-03 14:02:56 -0500222
Tejun Heoccf02aa2014-02-03 14:02:57 -0500223 kernfs_unmap_bin_file(kn);
224
Tejun Heo35beab02014-02-03 14:02:56 -0500225 mutex_lock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500226}
227
Tejun Heofd7b9f72013-11-28 14:54:33 -0500228/**
Tejun Heo324a56e2013-12-11 14:11:53 -0500229 * kernfs_get - get a reference count on a kernfs_node
230 * @kn: the target kernfs_node
Tejun Heofd7b9f72013-11-28 14:54:33 -0500231 */
Tejun Heo324a56e2013-12-11 14:11:53 -0500232void kernfs_get(struct kernfs_node *kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500233{
Tejun Heo324a56e2013-12-11 14:11:53 -0500234 if (kn) {
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500235 WARN_ON(!atomic_read(&kn->count));
236 atomic_inc(&kn->count);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500237 }
238}
239EXPORT_SYMBOL_GPL(kernfs_get);
240
241/**
Tejun Heo324a56e2013-12-11 14:11:53 -0500242 * kernfs_put - put a reference count on a kernfs_node
243 * @kn: the target kernfs_node
Tejun Heofd7b9f72013-11-28 14:54:33 -0500244 *
Tejun Heo324a56e2013-12-11 14:11:53 -0500245 * Put a reference count of @kn and destroy it if it reached zero.
Tejun Heofd7b9f72013-11-28 14:54:33 -0500246 */
Tejun Heo324a56e2013-12-11 14:11:53 -0500247void kernfs_put(struct kernfs_node *kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500248{
Tejun Heo324a56e2013-12-11 14:11:53 -0500249 struct kernfs_node *parent;
Tejun Heoba7443b2013-11-28 14:54:40 -0500250 struct kernfs_root *root;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500251
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500252 if (!kn || !atomic_dec_and_test(&kn->count))
Tejun Heofd7b9f72013-11-28 14:54:33 -0500253 return;
Tejun Heo324a56e2013-12-11 14:11:53 -0500254 root = kernfs_root(kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500255 repeat:
Greg Kroah-Hartman798c75a2014-01-13 14:36:03 -0800256 /* Moving/renaming is always done while holding reference.
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500257 * kn->parent won't change beneath us.
Tejun Heofd7b9f72013-11-28 14:54:33 -0500258 */
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500259 parent = kn->parent;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500260
Greg Kroah-Hartman798c75a2014-01-13 14:36:03 -0800261 WARN(!(kn->flags & KERNFS_REMOVED), "kernfs: free using entry: %s/%s\n",
262 parent ? parent->name : "", kn->name);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500263
Tejun Heodf23fc32013-12-11 14:11:56 -0500264 if (kernfs_type(kn) == KERNFS_LINK)
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500265 kernfs_put(kn->symlink.target_kn);
Tejun Heo2063d602013-12-11 16:02:57 -0500266 if (!(kn->flags & KERNFS_STATIC_NAME))
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500267 kfree(kn->name);
268 if (kn->iattr) {
269 if (kn->iattr->ia_secdata)
270 security_release_secctx(kn->iattr->ia_secdata,
271 kn->iattr->ia_secdata_len);
272 simple_xattrs_free(&kn->iattr->xattrs);
Tejun Heo23223922013-11-23 17:40:02 -0500273 }
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500274 kfree(kn->iattr);
275 ida_simple_remove(&root->ino_ida, kn->ino);
Tejun Heoa797bfc2013-12-11 14:11:57 -0500276 kmem_cache_free(kernfs_node_cache, kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500277
Tejun Heo324a56e2013-12-11 14:11:53 -0500278 kn = parent;
279 if (kn) {
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500280 if (atomic_dec_and_test(&kn->count))
Tejun Heoba7443b2013-11-28 14:54:40 -0500281 goto repeat;
282 } else {
Tejun Heo324a56e2013-12-11 14:11:53 -0500283 /* just released the root kn, free @root too */
Tejun Heobc755552013-11-28 14:54:41 -0500284 ida_destroy(&root->ino_ida);
Tejun Heoba7443b2013-11-28 14:54:40 -0500285 kfree(root);
286 }
Tejun Heofd7b9f72013-11-28 14:54:33 -0500287}
288EXPORT_SYMBOL_GPL(kernfs_put);
289
Tejun Heoc637b8a2013-12-11 14:11:58 -0500290static int kernfs_dop_revalidate(struct dentry *dentry, unsigned int flags)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500291{
Tejun Heo324a56e2013-12-11 14:11:53 -0500292 struct kernfs_node *kn;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500293
294 if (flags & LOOKUP_RCU)
295 return -ECHILD;
296
Tejun Heo19bbb922013-12-11 16:02:59 -0500297 /* Always perform fresh lookup for negatives */
298 if (!dentry->d_inode)
299 goto out_bad_unlocked;
300
Tejun Heo324a56e2013-12-11 14:11:53 -0500301 kn = dentry->d_fsdata;
Tejun Heoa797bfc2013-12-11 14:11:57 -0500302 mutex_lock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500303
Greg Kroah-Hartman798c75a2014-01-13 14:36:03 -0800304 /* The kernfs node has been deleted */
305 if (kn->flags & KERNFS_REMOVED)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500306 goto out_bad;
307
Tejun Heoc637b8a2013-12-11 14:11:58 -0500308 /* The kernfs node has been moved? */
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500309 if (dentry->d_parent->d_fsdata != kn->parent)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500310 goto out_bad;
311
Tejun Heoc637b8a2013-12-11 14:11:58 -0500312 /* The kernfs node has been renamed */
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500313 if (strcmp(dentry->d_name.name, kn->name) != 0)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500314 goto out_bad;
315
Tejun Heoc637b8a2013-12-11 14:11:58 -0500316 /* The kernfs node has been moved to a different namespace */
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500317 if (kn->parent && kernfs_ns_enabled(kn->parent) &&
Tejun Heoc525aad2013-12-11 14:11:55 -0500318 kernfs_info(dentry->d_sb)->ns != kn->ns)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500319 goto out_bad;
320
Tejun Heoa797bfc2013-12-11 14:11:57 -0500321 mutex_unlock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500322out_valid:
323 return 1;
324out_bad:
Tejun Heoa797bfc2013-12-11 14:11:57 -0500325 mutex_unlock(&kernfs_mutex);
Tejun Heo19bbb922013-12-11 16:02:59 -0500326out_bad_unlocked:
327 /*
328 * @dentry doesn't match the underlying kernfs node, drop the
329 * dentry and force lookup. If we have submounts we must allow the
330 * vfs caches to lie about the state of the filesystem to prevent
331 * leaks and other nasty things, so use check_submounts_and_drop()
332 * instead of d_drop().
Tejun Heofd7b9f72013-11-28 14:54:33 -0500333 */
334 if (check_submounts_and_drop(dentry) != 0)
335 goto out_valid;
336
337 return 0;
338}
339
Tejun Heoc637b8a2013-12-11 14:11:58 -0500340static void kernfs_dop_release(struct dentry *dentry)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500341{
342 kernfs_put(dentry->d_fsdata);
343}
344
Tejun Heoa797bfc2013-12-11 14:11:57 -0500345const struct dentry_operations kernfs_dops = {
Tejun Heoc637b8a2013-12-11 14:11:58 -0500346 .d_revalidate = kernfs_dop_revalidate,
Tejun Heoc637b8a2013-12-11 14:11:58 -0500347 .d_release = kernfs_dop_release,
Tejun Heofd7b9f72013-11-28 14:54:33 -0500348};
349
Tejun Heodb4aad22014-01-17 09:58:25 -0500350static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root,
351 const char *name, umode_t mode,
352 unsigned flags)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500353{
354 char *dup_name = NULL;
Tejun Heo324a56e2013-12-11 14:11:53 -0500355 struct kernfs_node *kn;
Tejun Heobc755552013-11-28 14:54:41 -0500356 int ret;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500357
Tejun Heo2063d602013-12-11 16:02:57 -0500358 if (!(flags & KERNFS_STATIC_NAME)) {
Tejun Heofd7b9f72013-11-28 14:54:33 -0500359 name = dup_name = kstrdup(name, GFP_KERNEL);
360 if (!name)
361 return NULL;
362 }
363
Tejun Heoa797bfc2013-12-11 14:11:57 -0500364 kn = kmem_cache_zalloc(kernfs_node_cache, GFP_KERNEL);
Tejun Heo324a56e2013-12-11 14:11:53 -0500365 if (!kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500366 goto err_out1;
367
Tejun Heobc755552013-11-28 14:54:41 -0500368 ret = ida_simple_get(&root->ino_ida, 1, 0, GFP_KERNEL);
369 if (ret < 0)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500370 goto err_out2;
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500371 kn->ino = ret;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500372
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500373 atomic_set(&kn->count, 1);
Greg Kroah-Hartman798c75a2014-01-13 14:36:03 -0800374 atomic_set(&kn->active, 0);
Tejun Heo35beab02014-02-03 14:02:56 -0500375 RB_CLEAR_NODE(&kn->rb);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500376
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500377 kn->name = name;
378 kn->mode = mode;
Greg Kroah-Hartman798c75a2014-01-13 14:36:03 -0800379 kn->flags = flags | KERNFS_REMOVED;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500380
Tejun Heo324a56e2013-12-11 14:11:53 -0500381 return kn;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500382
383 err_out2:
Tejun Heoa797bfc2013-12-11 14:11:57 -0500384 kmem_cache_free(kernfs_node_cache, kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500385 err_out1:
386 kfree(dup_name);
387 return NULL;
388}
389
Tejun Heodb4aad22014-01-17 09:58:25 -0500390struct kernfs_node *kernfs_new_node(struct kernfs_node *parent,
391 const char *name, umode_t mode,
392 unsigned flags)
393{
394 struct kernfs_node *kn;
395
396 kn = __kernfs_new_node(kernfs_root(parent), name, mode, flags);
397 if (kn) {
398 kernfs_get(parent);
399 kn->parent = parent;
400 }
401 return kn;
402}
403
Tejun Heofd7b9f72013-11-28 14:54:33 -0500404/**
Tejun Heoc637b8a2013-12-11 14:11:58 -0500405 * kernfs_add_one - add kernfs_node to parent without warning
Tejun Heo324a56e2013-12-11 14:11:53 -0500406 * @kn: kernfs_node to be added
Tejun Heofd7b9f72013-11-28 14:54:33 -0500407 *
Tejun Heodb4aad22014-01-17 09:58:25 -0500408 * The caller must already have initialized @kn->parent. This
409 * function increments nlink of the parent's inode if @kn is a
410 * directory and link into the children list of the parent.
Tejun Heofd7b9f72013-11-28 14:54:33 -0500411 *
Tejun Heofd7b9f72013-11-28 14:54:33 -0500412 * RETURNS:
413 * 0 on success, -EEXIST if entry with the given name already
414 * exists.
415 */
Tejun Heo988cd7a2014-02-03 14:02:58 -0500416int kernfs_add_one(struct kernfs_node *kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500417{
Tejun Heodb4aad22014-01-17 09:58:25 -0500418 struct kernfs_node *parent = kn->parent;
Tejun Heoc525aad2013-12-11 14:11:55 -0500419 struct kernfs_iattrs *ps_iattr;
Tejun Heo988cd7a2014-02-03 14:02:58 -0500420 bool has_ns;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500421 int ret;
422
Tejun Heo988cd7a2014-02-03 14:02:58 -0500423 mutex_lock(&kernfs_mutex);
424
425 ret = -EINVAL;
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))
429 goto out_unlock;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500430
Tejun Heodf23fc32013-12-11 14:11:56 -0500431 if (kernfs_type(parent) != KERNFS_DIR)
Tejun Heo988cd7a2014-02-03 14:02:58 -0500432 goto out_unlock;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500433
Tejun Heo988cd7a2014-02-03 14:02:58 -0500434 ret = -ENOENT;
Greg Kroah-Hartman798c75a2014-01-13 14:36:03 -0800435 if (parent->flags & KERNFS_REMOVED)
Tejun Heo988cd7a2014-02-03 14:02:58 -0500436 goto out_unlock;
Greg Kroah-Hartman798c75a2014-01-13 14:36:03 -0800437
Tejun Heoc637b8a2013-12-11 14:11:58 -0500438 kn->hash = kernfs_name_hash(kn->name, kn->ns);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500439
Tejun Heoc637b8a2013-12-11 14:11:58 -0500440 ret = kernfs_link_sibling(kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500441 if (ret)
Tejun Heo988cd7a2014-02-03 14:02:58 -0500442 goto out_unlock;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500443
444 /* Update timestamps on the parent */
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500445 ps_iattr = parent->iattr;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500446 if (ps_iattr) {
447 struct iattr *ps_iattrs = &ps_iattr->ia_iattr;
448 ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME;
449 }
450
451 /* Mark the entry added into directory tree */
Greg Kroah-Hartman798c75a2014-01-13 14:36:03 -0800452 kn->flags &= ~KERNFS_REMOVED;
Tejun Heo988cd7a2014-02-03 14:02:58 -0500453 ret = 0;
454out_unlock:
Tejun Heoa797bfc2013-12-11 14:11:57 -0500455 mutex_unlock(&kernfs_mutex);
Tejun Heo988cd7a2014-02-03 14:02:58 -0500456 return ret;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500457}
458
459/**
Tejun Heo324a56e2013-12-11 14:11:53 -0500460 * kernfs_find_ns - find kernfs_node with the given name
461 * @parent: kernfs_node to search under
Tejun Heofd7b9f72013-11-28 14:54:33 -0500462 * @name: name to look for
463 * @ns: the namespace tag to use
464 *
Tejun Heo324a56e2013-12-11 14:11:53 -0500465 * Look for kernfs_node with name @name under @parent. Returns pointer to
466 * the found kernfs_node on success, %NULL on failure.
Tejun Heofd7b9f72013-11-28 14:54:33 -0500467 */
Tejun Heo324a56e2013-12-11 14:11:53 -0500468static struct kernfs_node *kernfs_find_ns(struct kernfs_node *parent,
469 const unsigned char *name,
470 const void *ns)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500471{
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500472 struct rb_node *node = parent->dir.children.rb_node;
Tejun Heoac9bba02013-11-29 17:19:09 -0500473 bool has_ns = kernfs_ns_enabled(parent);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500474 unsigned int hash;
475
Tejun Heoa797bfc2013-12-11 14:11:57 -0500476 lockdep_assert_held(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500477
478 if (has_ns != (bool)ns) {
Tejun Heoc637b8a2013-12-11 14:11:58 -0500479 WARN(1, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n",
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500480 has_ns ? "required" : "invalid", parent->name, name);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500481 return NULL;
482 }
483
Tejun Heoc637b8a2013-12-11 14:11:58 -0500484 hash = kernfs_name_hash(name, ns);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500485 while (node) {
Tejun Heo324a56e2013-12-11 14:11:53 -0500486 struct kernfs_node *kn;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500487 int result;
488
Tejun Heo324a56e2013-12-11 14:11:53 -0500489 kn = rb_to_kn(node);
Tejun Heoc637b8a2013-12-11 14:11:58 -0500490 result = kernfs_name_compare(hash, name, ns, kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500491 if (result < 0)
492 node = node->rb_left;
493 else if (result > 0)
494 node = node->rb_right;
495 else
Tejun Heo324a56e2013-12-11 14:11:53 -0500496 return kn;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500497 }
498 return NULL;
499}
500
501/**
Tejun Heo324a56e2013-12-11 14:11:53 -0500502 * kernfs_find_and_get_ns - find and get kernfs_node with the given name
503 * @parent: kernfs_node to search under
Tejun Heofd7b9f72013-11-28 14:54:33 -0500504 * @name: name to look for
505 * @ns: the namespace tag to use
506 *
Tejun Heo324a56e2013-12-11 14:11:53 -0500507 * Look for kernfs_node with name @name under @parent and get a reference
Tejun Heofd7b9f72013-11-28 14:54:33 -0500508 * if found. This function may sleep and returns pointer to the found
Tejun Heo324a56e2013-12-11 14:11:53 -0500509 * kernfs_node on success, %NULL on failure.
Tejun Heofd7b9f72013-11-28 14:54:33 -0500510 */
Tejun Heo324a56e2013-12-11 14:11:53 -0500511struct kernfs_node *kernfs_find_and_get_ns(struct kernfs_node *parent,
512 const char *name, const void *ns)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500513{
Tejun Heo324a56e2013-12-11 14:11:53 -0500514 struct kernfs_node *kn;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500515
Tejun Heoa797bfc2013-12-11 14:11:57 -0500516 mutex_lock(&kernfs_mutex);
Tejun Heo324a56e2013-12-11 14:11:53 -0500517 kn = kernfs_find_ns(parent, name, ns);
518 kernfs_get(kn);
Tejun Heoa797bfc2013-12-11 14:11:57 -0500519 mutex_unlock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500520
Tejun Heo324a56e2013-12-11 14:11:53 -0500521 return kn;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500522}
523EXPORT_SYMBOL_GPL(kernfs_find_and_get_ns);
524
525/**
Tejun Heoba7443b2013-11-28 14:54:40 -0500526 * kernfs_create_root - create a new kernfs hierarchy
Tejun Heo80b9bbe2013-12-11 16:03:00 -0500527 * @kdops: optional directory syscall operations for the hierarchy
Tejun Heoba7443b2013-11-28 14:54:40 -0500528 * @priv: opaque data associated with the new directory
529 *
530 * Returns the root of the new hierarchy on success, ERR_PTR() value on
531 * failure.
532 */
Tejun Heo80b9bbe2013-12-11 16:03:00 -0500533struct kernfs_root *kernfs_create_root(struct kernfs_dir_ops *kdops, void *priv)
Tejun Heoba7443b2013-11-28 14:54:40 -0500534{
535 struct kernfs_root *root;
Tejun Heo324a56e2013-12-11 14:11:53 -0500536 struct kernfs_node *kn;
Tejun Heoba7443b2013-11-28 14:54:40 -0500537
538 root = kzalloc(sizeof(*root), GFP_KERNEL);
539 if (!root)
540 return ERR_PTR(-ENOMEM);
541
Tejun Heobc755552013-11-28 14:54:41 -0500542 ida_init(&root->ino_ida);
543
Tejun Heodb4aad22014-01-17 09:58:25 -0500544 kn = __kernfs_new_node(root, "", S_IFDIR | S_IRUGO | S_IXUGO,
545 KERNFS_DIR);
Tejun Heo324a56e2013-12-11 14:11:53 -0500546 if (!kn) {
Tejun Heobc755552013-11-28 14:54:41 -0500547 ida_destroy(&root->ino_ida);
Tejun Heoba7443b2013-11-28 14:54:40 -0500548 kfree(root);
549 return ERR_PTR(-ENOMEM);
550 }
551
Greg Kroah-Hartman798c75a2014-01-13 14:36:03 -0800552 kn->flags &= ~KERNFS_REMOVED;
Tejun Heo324a56e2013-12-11 14:11:53 -0500553 kn->priv = priv;
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500554 kn->dir.root = root;
Tejun Heoba7443b2013-11-28 14:54:40 -0500555
Tejun Heo80b9bbe2013-12-11 16:03:00 -0500556 root->dir_ops = kdops;
Tejun Heo324a56e2013-12-11 14:11:53 -0500557 root->kn = kn;
Tejun Heoabd54f02014-02-03 14:02:55 -0500558 init_waitqueue_head(&root->deactivate_waitq);
Tejun Heoba7443b2013-11-28 14:54:40 -0500559
560 return root;
561}
562
563/**
564 * kernfs_destroy_root - destroy a kernfs hierarchy
565 * @root: root of the hierarchy to destroy
566 *
567 * Destroy the hierarchy anchored at @root by removing all existing
568 * directories and destroying @root.
569 */
570void kernfs_destroy_root(struct kernfs_root *root)
571{
Tejun Heo324a56e2013-12-11 14:11:53 -0500572 kernfs_remove(root->kn); /* will also free @root */
Tejun Heoba7443b2013-11-28 14:54:40 -0500573}
574
575/**
Tejun Heofd7b9f72013-11-28 14:54:33 -0500576 * kernfs_create_dir_ns - create a directory
577 * @parent: parent in which to create a new directory
578 * @name: name of the new directory
Tejun Heobb8b9d02013-12-11 16:02:55 -0500579 * @mode: mode of the new directory
Tejun Heofd7b9f72013-11-28 14:54:33 -0500580 * @priv: opaque data associated with the new directory
581 * @ns: optional namespace tag of the directory
582 *
583 * Returns the created node on success, ERR_PTR() value on failure.
584 */
Tejun Heo324a56e2013-12-11 14:11:53 -0500585struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent,
Tejun Heobb8b9d02013-12-11 16:02:55 -0500586 const char *name, umode_t mode,
587 void *priv, const void *ns)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500588{
Tejun Heo324a56e2013-12-11 14:11:53 -0500589 struct kernfs_node *kn;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500590 int rc;
591
592 /* allocate */
Tejun Heodb4aad22014-01-17 09:58:25 -0500593 kn = kernfs_new_node(parent, name, mode | S_IFDIR, KERNFS_DIR);
Tejun Heo324a56e2013-12-11 14:11:53 -0500594 if (!kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500595 return ERR_PTR(-ENOMEM);
596
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500597 kn->dir.root = parent->dir.root;
598 kn->ns = ns;
Tejun Heo324a56e2013-12-11 14:11:53 -0500599 kn->priv = priv;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500600
601 /* link in */
Tejun Heo988cd7a2014-02-03 14:02:58 -0500602 rc = kernfs_add_one(kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500603 if (!rc)
Tejun Heo324a56e2013-12-11 14:11:53 -0500604 return kn;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500605
Tejun Heo324a56e2013-12-11 14:11:53 -0500606 kernfs_put(kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500607 return ERR_PTR(rc);
608}
609
Tejun Heoc637b8a2013-12-11 14:11:58 -0500610static struct dentry *kernfs_iop_lookup(struct inode *dir,
611 struct dentry *dentry,
612 unsigned int flags)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500613{
Tejun Heo19bbb922013-12-11 16:02:59 -0500614 struct dentry *ret;
Tejun Heo324a56e2013-12-11 14:11:53 -0500615 struct kernfs_node *parent = dentry->d_parent->d_fsdata;
616 struct kernfs_node *kn;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500617 struct inode *inode;
618 const void *ns = NULL;
619
Tejun Heoa797bfc2013-12-11 14:11:57 -0500620 mutex_lock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500621
Tejun Heo324a56e2013-12-11 14:11:53 -0500622 if (kernfs_ns_enabled(parent))
Tejun Heoc525aad2013-12-11 14:11:55 -0500623 ns = kernfs_info(dir->i_sb)->ns;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500624
Tejun Heo324a56e2013-12-11 14:11:53 -0500625 kn = kernfs_find_ns(parent, dentry->d_name.name, ns);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500626
627 /* no such entry */
Tejun Heo324a56e2013-12-11 14:11:53 -0500628 if (!kn) {
Tejun Heo19bbb922013-12-11 16:02:59 -0500629 ret = NULL;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500630 goto out_unlock;
631 }
Tejun Heo324a56e2013-12-11 14:11:53 -0500632 kernfs_get(kn);
633 dentry->d_fsdata = kn;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500634
635 /* attach dentry and inode */
Tejun Heoc637b8a2013-12-11 14:11:58 -0500636 inode = kernfs_get_inode(dir->i_sb, kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500637 if (!inode) {
638 ret = ERR_PTR(-ENOMEM);
639 goto out_unlock;
640 }
641
642 /* instantiate and hash dentry */
643 ret = d_materialise_unique(dentry, inode);
644 out_unlock:
Tejun Heoa797bfc2013-12-11 14:11:57 -0500645 mutex_unlock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500646 return ret;
647}
648
Tejun Heo80b9bbe2013-12-11 16:03:00 -0500649static int kernfs_iop_mkdir(struct inode *dir, struct dentry *dentry,
650 umode_t mode)
651{
652 struct kernfs_node *parent = dir->i_private;
653 struct kernfs_dir_ops *kdops = kernfs_root(parent)->dir_ops;
654
655 if (!kdops || !kdops->mkdir)
656 return -EPERM;
657
658 return kdops->mkdir(parent, dentry->d_name.name, mode);
659}
660
661static int kernfs_iop_rmdir(struct inode *dir, struct dentry *dentry)
662{
663 struct kernfs_node *kn = dentry->d_fsdata;
664 struct kernfs_dir_ops *kdops = kernfs_root(kn)->dir_ops;
665
666 if (!kdops || !kdops->rmdir)
667 return -EPERM;
668
669 return kdops->rmdir(kn);
670}
671
672static int kernfs_iop_rename(struct inode *old_dir, struct dentry *old_dentry,
673 struct inode *new_dir, struct dentry *new_dentry)
674{
675 struct kernfs_node *kn = old_dentry->d_fsdata;
676 struct kernfs_node *new_parent = new_dir->i_private;
677 struct kernfs_dir_ops *kdops = kernfs_root(kn)->dir_ops;
678
679 if (!kdops || !kdops->rename)
680 return -EPERM;
681
682 return kdops->rename(kn, new_parent, new_dentry->d_name.name);
683}
684
Tejun Heoa797bfc2013-12-11 14:11:57 -0500685const struct inode_operations kernfs_dir_iops = {
Tejun Heoc637b8a2013-12-11 14:11:58 -0500686 .lookup = kernfs_iop_lookup,
687 .permission = kernfs_iop_permission,
688 .setattr = kernfs_iop_setattr,
689 .getattr = kernfs_iop_getattr,
690 .setxattr = kernfs_iop_setxattr,
691 .removexattr = kernfs_iop_removexattr,
692 .getxattr = kernfs_iop_getxattr,
693 .listxattr = kernfs_iop_listxattr,
Tejun Heo80b9bbe2013-12-11 16:03:00 -0500694
695 .mkdir = kernfs_iop_mkdir,
696 .rmdir = kernfs_iop_rmdir,
697 .rename = kernfs_iop_rename,
Tejun Heofd7b9f72013-11-28 14:54:33 -0500698};
699
Tejun Heoc637b8a2013-12-11 14:11:58 -0500700static struct kernfs_node *kernfs_leftmost_descendant(struct kernfs_node *pos)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500701{
Tejun Heo324a56e2013-12-11 14:11:53 -0500702 struct kernfs_node *last;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500703
704 while (true) {
705 struct rb_node *rbn;
706
707 last = pos;
708
Tejun Heodf23fc32013-12-11 14:11:56 -0500709 if (kernfs_type(pos) != KERNFS_DIR)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500710 break;
711
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500712 rbn = rb_first(&pos->dir.children);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500713 if (!rbn)
714 break;
715
Tejun Heo324a56e2013-12-11 14:11:53 -0500716 pos = rb_to_kn(rbn);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500717 }
718
719 return last;
720}
721
722/**
Tejun Heoc637b8a2013-12-11 14:11:58 -0500723 * kernfs_next_descendant_post - find the next descendant for post-order walk
Tejun Heofd7b9f72013-11-28 14:54:33 -0500724 * @pos: the current position (%NULL to initiate traversal)
Tejun Heo324a56e2013-12-11 14:11:53 -0500725 * @root: kernfs_node whose descendants to walk
Tejun Heofd7b9f72013-11-28 14:54:33 -0500726 *
727 * Find the next descendant to visit for post-order traversal of @root's
728 * descendants. @root is included in the iteration and the last node to be
729 * visited.
730 */
Tejun Heoc637b8a2013-12-11 14:11:58 -0500731static struct kernfs_node *kernfs_next_descendant_post(struct kernfs_node *pos,
732 struct kernfs_node *root)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500733{
734 struct rb_node *rbn;
735
Tejun Heoa797bfc2013-12-11 14:11:57 -0500736 lockdep_assert_held(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500737
738 /* if first iteration, visit leftmost descendant which may be root */
739 if (!pos)
Tejun Heoc637b8a2013-12-11 14:11:58 -0500740 return kernfs_leftmost_descendant(root);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500741
742 /* if we visited @root, we're done */
743 if (pos == root)
744 return NULL;
745
746 /* if there's an unvisited sibling, visit its leftmost descendant */
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500747 rbn = rb_next(&pos->rb);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500748 if (rbn)
Tejun Heoc637b8a2013-12-11 14:11:58 -0500749 return kernfs_leftmost_descendant(rb_to_kn(rbn));
Tejun Heofd7b9f72013-11-28 14:54:33 -0500750
751 /* no sibling left, visit parent */
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500752 return pos->parent;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500753}
754
Tejun Heo988cd7a2014-02-03 14:02:58 -0500755static void __kernfs_remove(struct kernfs_node *kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500756{
Tejun Heo35beab02014-02-03 14:02:56 -0500757 struct kernfs_node *pos;
758
759 lockdep_assert_held(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500760
Greg Kroah-Hartmance9b4992014-01-13 13:50:31 -0800761 if (!kn)
762 return;
763
Tejun Heoc637b8a2013-12-11 14:11:58 -0500764 pr_debug("kernfs %s: removing\n", kn->name);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500765
Tejun Heo35beab02014-02-03 14:02:56 -0500766 /* disable lookup and node creation under @kn */
767 pos = NULL;
768 while ((pos = kernfs_next_descendant_post(pos, kn)))
769 pos->flags |= KERNFS_REMOVED;
770
771 /* deactivate and unlink the subtree node-by-node */
Tejun Heofd7b9f72013-11-28 14:54:33 -0500772 do {
Tejun Heo35beab02014-02-03 14:02:56 -0500773 pos = kernfs_leftmost_descendant(kn);
774
775 /*
776 * kernfs_deactivate() drops kernfs_mutex temporarily and
777 * @pos's base ref could have been put by someone else by
778 * the time the function returns. Make sure it doesn't go
779 * away underneath us.
780 */
781 kernfs_get(pos);
782
783 kernfs_deactivate(pos);
784
785 /*
786 * kernfs_unlink_sibling() succeeds once per node. Use it
787 * to decide who's responsible for cleanups.
788 */
789 if (!pos->parent || kernfs_unlink_sibling(pos)) {
790 struct kernfs_iattrs *ps_iattr =
791 pos->parent ? pos->parent->iattr : NULL;
792
793 /* update timestamps on the parent */
794 if (ps_iattr) {
795 ps_iattr->ia_iattr.ia_ctime = CURRENT_TIME;
796 ps_iattr->ia_iattr.ia_mtime = CURRENT_TIME;
797 }
798
Tejun Heo988cd7a2014-02-03 14:02:58 -0500799 kernfs_put(pos);
Tejun Heo35beab02014-02-03 14:02:56 -0500800 }
801
802 kernfs_put(pos);
803 } while (pos != kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500804}
805
806/**
Tejun Heo324a56e2013-12-11 14:11:53 -0500807 * kernfs_remove - remove a kernfs_node recursively
808 * @kn: the kernfs_node to remove
Tejun Heofd7b9f72013-11-28 14:54:33 -0500809 *
Tejun Heo324a56e2013-12-11 14:11:53 -0500810 * Remove @kn along with all its subdirectories and files.
Tejun Heofd7b9f72013-11-28 14:54:33 -0500811 */
Tejun Heo324a56e2013-12-11 14:11:53 -0500812void kernfs_remove(struct kernfs_node *kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500813{
Tejun Heo988cd7a2014-02-03 14:02:58 -0500814 mutex_lock(&kernfs_mutex);
815 __kernfs_remove(kn);
816 mutex_unlock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500817}
818
819/**
Tejun Heo324a56e2013-12-11 14:11:53 -0500820 * kernfs_remove_by_name_ns - find a kernfs_node by name and remove it
821 * @parent: parent of the target
822 * @name: name of the kernfs_node to remove
823 * @ns: namespace tag of the kernfs_node to remove
Tejun Heofd7b9f72013-11-28 14:54:33 -0500824 *
Tejun Heo324a56e2013-12-11 14:11:53 -0500825 * Look for the kernfs_node with @name and @ns under @parent and remove it.
826 * Returns 0 on success, -ENOENT if such entry doesn't exist.
Tejun Heofd7b9f72013-11-28 14:54:33 -0500827 */
Tejun Heo324a56e2013-12-11 14:11:53 -0500828int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name,
Tejun Heofd7b9f72013-11-28 14:54:33 -0500829 const void *ns)
830{
Tejun Heo324a56e2013-12-11 14:11:53 -0500831 struct kernfs_node *kn;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500832
Tejun Heo324a56e2013-12-11 14:11:53 -0500833 if (!parent) {
Tejun Heoc637b8a2013-12-11 14:11:58 -0500834 WARN(1, KERN_WARNING "kernfs: can not remove '%s', no directory\n",
Tejun Heofd7b9f72013-11-28 14:54:33 -0500835 name);
836 return -ENOENT;
837 }
838
Tejun Heo988cd7a2014-02-03 14:02:58 -0500839 mutex_lock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500840
Tejun Heo324a56e2013-12-11 14:11:53 -0500841 kn = kernfs_find_ns(parent, name, ns);
842 if (kn)
Tejun Heo988cd7a2014-02-03 14:02:58 -0500843 __kernfs_remove(kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500844
Tejun Heo988cd7a2014-02-03 14:02:58 -0500845 mutex_unlock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500846
Tejun Heo324a56e2013-12-11 14:11:53 -0500847 if (kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500848 return 0;
849 else
850 return -ENOENT;
851}
852
853/**
854 * kernfs_rename_ns - move and rename a kernfs_node
Tejun Heo324a56e2013-12-11 14:11:53 -0500855 * @kn: target node
Tejun Heofd7b9f72013-11-28 14:54:33 -0500856 * @new_parent: new parent to put @sd under
857 * @new_name: new name
858 * @new_ns: new namespace tag
859 */
Tejun Heo324a56e2013-12-11 14:11:53 -0500860int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent,
Tejun Heofd7b9f72013-11-28 14:54:33 -0500861 const char *new_name, const void *new_ns)
862{
863 int error;
864
Tejun Heoae343722014-01-10 08:57:21 -0500865 mutex_lock(&kernfs_mutex);
Tejun Heod0ae3d42013-12-11 16:02:56 -0500866
Greg Kroah-Hartman798c75a2014-01-13 14:36:03 -0800867 error = -ENOENT;
868 if ((kn->flags | new_parent->flags) & KERNFS_REMOVED)
869 goto out;
870
Tejun Heofd7b9f72013-11-28 14:54:33 -0500871 error = 0;
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500872 if ((kn->parent == new_parent) && (kn->ns == new_ns) &&
873 (strcmp(kn->name, new_name) == 0))
Greg Kroah-Hartman798c75a2014-01-13 14:36:03 -0800874 goto out; /* nothing to rename */
Tejun Heofd7b9f72013-11-28 14:54:33 -0500875
876 error = -EEXIST;
877 if (kernfs_find_ns(new_parent, new_name, new_ns))
Greg Kroah-Hartman798c75a2014-01-13 14:36:03 -0800878 goto out;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500879
Tejun Heo324a56e2013-12-11 14:11:53 -0500880 /* rename kernfs_node */
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500881 if (strcmp(kn->name, new_name) != 0) {
Tejun Heofd7b9f72013-11-28 14:54:33 -0500882 error = -ENOMEM;
883 new_name = kstrdup(new_name, GFP_KERNEL);
884 if (!new_name)
Greg Kroah-Hartman798c75a2014-01-13 14:36:03 -0800885 goto out;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500886
Tejun Heo47a52e92013-12-11 16:02:58 -0500887 if (kn->flags & KERNFS_STATIC_NAME)
888 kn->flags &= ~KERNFS_STATIC_NAME;
889 else
890 kfree(kn->name);
891
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500892 kn->name = new_name;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500893 }
894
895 /*
896 * Move to the appropriate place in the appropriate directories rbtree.
897 */
Tejun Heoc637b8a2013-12-11 14:11:58 -0500898 kernfs_unlink_sibling(kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500899 kernfs_get(new_parent);
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500900 kernfs_put(kn->parent);
901 kn->ns = new_ns;
Tejun Heoc637b8a2013-12-11 14:11:58 -0500902 kn->hash = kernfs_name_hash(kn->name, kn->ns);
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500903 kn->parent = new_parent;
Tejun Heoc637b8a2013-12-11 14:11:58 -0500904 kernfs_link_sibling(kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500905
906 error = 0;
Greg Kroah-Hartman798c75a2014-01-13 14:36:03 -0800907 out:
Tejun Heoa797bfc2013-12-11 14:11:57 -0500908 mutex_unlock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500909 return error;
910}
911
Tejun Heofd7b9f72013-11-28 14:54:33 -0500912/* Relationship between s_mode and the DT_xxx types */
Tejun Heo324a56e2013-12-11 14:11:53 -0500913static inline unsigned char dt_type(struct kernfs_node *kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500914{
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500915 return (kn->mode >> 12) & 15;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500916}
917
Tejun Heoc637b8a2013-12-11 14:11:58 -0500918static int kernfs_dir_fop_release(struct inode *inode, struct file *filp)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500919{
920 kernfs_put(filp->private_data);
921 return 0;
922}
923
Tejun Heoc637b8a2013-12-11 14:11:58 -0500924static struct kernfs_node *kernfs_dir_pos(const void *ns,
Tejun Heo324a56e2013-12-11 14:11:53 -0500925 struct kernfs_node *parent, loff_t hash, struct kernfs_node *pos)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500926{
927 if (pos) {
Greg Kroah-Hartman798c75a2014-01-13 14:36:03 -0800928 int valid = !(pos->flags & KERNFS_REMOVED) &&
929 pos->parent == parent && hash == pos->hash;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500930 kernfs_put(pos);
931 if (!valid)
932 pos = NULL;
933 }
934 if (!pos && (hash > 1) && (hash < INT_MAX)) {
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500935 struct rb_node *node = parent->dir.children.rb_node;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500936 while (node) {
Tejun Heo324a56e2013-12-11 14:11:53 -0500937 pos = rb_to_kn(node);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500938
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500939 if (hash < pos->hash)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500940 node = node->rb_left;
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500941 else if (hash > pos->hash)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500942 node = node->rb_right;
943 else
944 break;
945 }
946 }
947 /* Skip over entries in the wrong namespace */
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500948 while (pos && pos->ns != ns) {
949 struct rb_node *node = rb_next(&pos->rb);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500950 if (!node)
951 pos = NULL;
952 else
Tejun Heo324a56e2013-12-11 14:11:53 -0500953 pos = rb_to_kn(node);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500954 }
955 return pos;
956}
957
Tejun Heoc637b8a2013-12-11 14:11:58 -0500958static struct kernfs_node *kernfs_dir_next_pos(const void *ns,
Tejun Heo324a56e2013-12-11 14:11:53 -0500959 struct kernfs_node *parent, ino_t ino, struct kernfs_node *pos)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500960{
Tejun Heoc637b8a2013-12-11 14:11:58 -0500961 pos = kernfs_dir_pos(ns, parent, ino, pos);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500962 if (pos)
963 do {
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500964 struct rb_node *node = rb_next(&pos->rb);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500965 if (!node)
966 pos = NULL;
967 else
Tejun Heo324a56e2013-12-11 14:11:53 -0500968 pos = rb_to_kn(node);
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500969 } while (pos && pos->ns != ns);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500970 return pos;
971}
972
Tejun Heoc637b8a2013-12-11 14:11:58 -0500973static int kernfs_fop_readdir(struct file *file, struct dir_context *ctx)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500974{
975 struct dentry *dentry = file->f_path.dentry;
Tejun Heo324a56e2013-12-11 14:11:53 -0500976 struct kernfs_node *parent = dentry->d_fsdata;
977 struct kernfs_node *pos = file->private_data;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500978 const void *ns = NULL;
979
980 if (!dir_emit_dots(file, ctx))
981 return 0;
Tejun Heoa797bfc2013-12-11 14:11:57 -0500982 mutex_lock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500983
Tejun Heo324a56e2013-12-11 14:11:53 -0500984 if (kernfs_ns_enabled(parent))
Tejun Heoc525aad2013-12-11 14:11:55 -0500985 ns = kernfs_info(dentry->d_sb)->ns;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500986
Tejun Heoc637b8a2013-12-11 14:11:58 -0500987 for (pos = kernfs_dir_pos(ns, parent, ctx->pos, pos);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500988 pos;
Tejun Heoc637b8a2013-12-11 14:11:58 -0500989 pos = kernfs_dir_next_pos(ns, parent, ctx->pos, pos)) {
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500990 const char *name = pos->name;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500991 unsigned int type = dt_type(pos);
992 int len = strlen(name);
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500993 ino_t ino = pos->ino;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500994
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500995 ctx->pos = pos->hash;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500996 file->private_data = pos;
997 kernfs_get(pos);
998
Tejun Heoa797bfc2013-12-11 14:11:57 -0500999 mutex_unlock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001000 if (!dir_emit(ctx, name, len, ino, type))
1001 return 0;
Tejun Heoa797bfc2013-12-11 14:11:57 -05001002 mutex_lock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001003 }
Tejun Heoa797bfc2013-12-11 14:11:57 -05001004 mutex_unlock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001005 file->private_data = NULL;
1006 ctx->pos = INT_MAX;
1007 return 0;
1008}
1009
Tejun Heoc637b8a2013-12-11 14:11:58 -05001010static loff_t kernfs_dir_fop_llseek(struct file *file, loff_t offset,
1011 int whence)
Tejun Heofd7b9f72013-11-28 14:54:33 -05001012{
1013 struct inode *inode = file_inode(file);
1014 loff_t ret;
1015
1016 mutex_lock(&inode->i_mutex);
1017 ret = generic_file_llseek(file, offset, whence);
1018 mutex_unlock(&inode->i_mutex);
1019
1020 return ret;
1021}
1022
Tejun Heoa797bfc2013-12-11 14:11:57 -05001023const struct file_operations kernfs_dir_fops = {
Tejun Heofd7b9f72013-11-28 14:54:33 -05001024 .read = generic_read_dir,
Tejun Heoc637b8a2013-12-11 14:11:58 -05001025 .iterate = kernfs_fop_readdir,
1026 .release = kernfs_dir_fop_release,
1027 .llseek = kernfs_dir_fop_llseek,
Tejun Heofd7b9f72013-11-28 14:54:33 -05001028};