blob: 6acc9648f9869727dc9fb030d281d37bffdf3277 [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 Heo3eef34a2014-02-07 13:32:07 -050022static DEFINE_SPINLOCK(kernfs_rename_lock); /* kn->parent and ->name */
23static char kernfs_pr_cont_buf[PATH_MAX]; /* protected by rename_lock */
Tejun Heofd7b9f72013-11-28 14:54:33 -050024
Tejun Heoadc5e8b2013-12-11 14:11:54 -050025#define rb_to_kn(X) rb_entry((X), struct kernfs_node, rb)
Tejun Heofd7b9f72013-11-28 14:54:33 -050026
Tejun Heo81c173c2014-02-03 14:03:00 -050027static bool kernfs_active(struct kernfs_node *kn)
28{
29 lockdep_assert_held(&kernfs_mutex);
30 return atomic_read(&kn->active) >= 0;
31}
32
Tejun Heo182fd642014-02-03 14:02:59 -050033static bool kernfs_lockdep(struct kernfs_node *kn)
34{
35#ifdef CONFIG_DEBUG_LOCK_ALLOC
36 return kn->flags & KERNFS_LOCKDEP;
37#else
38 return false;
39#endif
40}
41
Tejun Heo3eef34a2014-02-07 13:32:07 -050042static int kernfs_name_locked(struct kernfs_node *kn, char *buf, size_t buflen)
43{
44 return strlcpy(buf, kn->parent ? kn->name : "/", buflen);
45}
46
47static char * __must_check kernfs_path_locked(struct kernfs_node *kn, char *buf,
48 size_t buflen)
49{
50 char *p = buf + buflen;
51 int len;
52
53 *--p = '\0';
54
55 do {
56 len = strlen(kn->name);
57 if (p - buf < len + 1) {
58 buf[0] = '\0';
59 p = NULL;
60 break;
61 }
62 p -= len;
63 memcpy(p, kn->name, len);
64 *--p = '/';
65 kn = kn->parent;
66 } while (kn && kn->parent);
67
68 return p;
69}
70
71/**
72 * kernfs_name - obtain the name of a given node
73 * @kn: kernfs_node of interest
74 * @buf: buffer to copy @kn's name into
75 * @buflen: size of @buf
76 *
77 * Copies the name of @kn into @buf of @buflen bytes. The behavior is
78 * similar to strlcpy(). It returns the length of @kn's name and if @buf
79 * isn't long enough, it's filled upto @buflen-1 and nul terminated.
80 *
81 * This function can be called from any context.
82 */
83int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen)
84{
85 unsigned long flags;
86 int ret;
87
88 spin_lock_irqsave(&kernfs_rename_lock, flags);
89 ret = kernfs_name_locked(kn, buf, buflen);
90 spin_unlock_irqrestore(&kernfs_rename_lock, flags);
91 return ret;
92}
93
94/**
95 * kernfs_path - build full path of a given node
96 * @kn: kernfs_node of interest
97 * @buf: buffer to copy @kn's name into
98 * @buflen: size of @buf
99 *
100 * Builds and returns the full path of @kn in @buf of @buflen bytes. The
101 * path is built from the end of @buf so the returned pointer usually
102 * doesn't match @buf. If @buf isn't long enough, @buf is nul terminated
103 * and %NULL is returned.
104 */
105char *kernfs_path(struct kernfs_node *kn, char *buf, size_t buflen)
106{
107 unsigned long flags;
108 char *p;
109
110 spin_lock_irqsave(&kernfs_rename_lock, flags);
111 p = kernfs_path_locked(kn, buf, buflen);
112 spin_unlock_irqrestore(&kernfs_rename_lock, flags);
113 return p;
114}
Tejun Heoe61734c2014-02-12 09:29:50 -0500115EXPORT_SYMBOL_GPL(kernfs_path);
Tejun Heo3eef34a2014-02-07 13:32:07 -0500116
117/**
118 * pr_cont_kernfs_name - pr_cont name of a kernfs_node
119 * @kn: kernfs_node of interest
120 *
121 * This function can be called from any context.
122 */
123void pr_cont_kernfs_name(struct kernfs_node *kn)
124{
125 unsigned long flags;
126
127 spin_lock_irqsave(&kernfs_rename_lock, flags);
128
129 kernfs_name_locked(kn, kernfs_pr_cont_buf, sizeof(kernfs_pr_cont_buf));
130 pr_cont("%s", kernfs_pr_cont_buf);
131
132 spin_unlock_irqrestore(&kernfs_rename_lock, flags);
133}
134
135/**
136 * pr_cont_kernfs_path - pr_cont path of a kernfs_node
137 * @kn: kernfs_node of interest
138 *
139 * This function can be called from any context.
140 */
141void pr_cont_kernfs_path(struct kernfs_node *kn)
142{
143 unsigned long flags;
144 char *p;
145
146 spin_lock_irqsave(&kernfs_rename_lock, flags);
147
148 p = kernfs_path_locked(kn, kernfs_pr_cont_buf,
149 sizeof(kernfs_pr_cont_buf));
150 if (p)
151 pr_cont("%s", p);
152 else
153 pr_cont("<name too long>");
154
155 spin_unlock_irqrestore(&kernfs_rename_lock, flags);
156}
157
158/**
159 * kernfs_get_parent - determine the parent node and pin it
160 * @kn: kernfs_node of interest
161 *
162 * Determines @kn's parent, pins and returns it. This function can be
163 * called from any context.
164 */
165struct kernfs_node *kernfs_get_parent(struct kernfs_node *kn)
166{
167 struct kernfs_node *parent;
168 unsigned long flags;
169
170 spin_lock_irqsave(&kernfs_rename_lock, flags);
171 parent = kn->parent;
172 kernfs_get(parent);
173 spin_unlock_irqrestore(&kernfs_rename_lock, flags);
174
175 return parent;
176}
177
Tejun Heofd7b9f72013-11-28 14:54:33 -0500178/**
Tejun Heoc637b8a2013-12-11 14:11:58 -0500179 * kernfs_name_hash
Tejun Heofd7b9f72013-11-28 14:54:33 -0500180 * @name: Null terminated string to hash
181 * @ns: Namespace tag to hash
182 *
183 * Returns 31 bit hash of ns + name (so it fits in an off_t )
184 */
Tejun Heoc637b8a2013-12-11 14:11:58 -0500185static unsigned int kernfs_name_hash(const char *name, const void *ns)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500186{
187 unsigned long hash = init_name_hash();
188 unsigned int len = strlen(name);
189 while (len--)
190 hash = partial_name_hash(*name++, hash);
191 hash = (end_name_hash(hash) ^ hash_ptr((void *)ns, 31));
192 hash &= 0x7fffffffU;
193 /* Reserve hash numbers 0, 1 and INT_MAX for magic directory entries */
Richard Cochran88391d42014-03-05 17:10:52 +0100194 if (hash < 2)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500195 hash += 2;
196 if (hash >= INT_MAX)
197 hash = INT_MAX - 1;
198 return hash;
199}
200
Tejun Heoc637b8a2013-12-11 14:11:58 -0500201static int kernfs_name_compare(unsigned int hash, const char *name,
202 const void *ns, const struct kernfs_node *kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500203{
Rasmus Villemoes72392ed2014-12-05 23:41:33 +0100204 if (hash < kn->hash)
205 return -1;
206 if (hash > kn->hash)
207 return 1;
208 if (ns < kn->ns)
209 return -1;
210 if (ns > kn->ns)
211 return 1;
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500212 return strcmp(name, kn->name);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500213}
214
Tejun Heoc637b8a2013-12-11 14:11:58 -0500215static int kernfs_sd_compare(const struct kernfs_node *left,
216 const struct kernfs_node *right)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500217{
Tejun Heoc637b8a2013-12-11 14:11:58 -0500218 return kernfs_name_compare(left->hash, left->name, left->ns, right);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500219}
220
221/**
Tejun Heoc637b8a2013-12-11 14:11:58 -0500222 * kernfs_link_sibling - link kernfs_node into sibling rbtree
Tejun Heo324a56e2013-12-11 14:11:53 -0500223 * @kn: kernfs_node of interest
Tejun Heofd7b9f72013-11-28 14:54:33 -0500224 *
Tejun Heo324a56e2013-12-11 14:11:53 -0500225 * Link @kn into its sibling rbtree which starts from
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500226 * @kn->parent->dir.children.
Tejun Heofd7b9f72013-11-28 14:54:33 -0500227 *
228 * Locking:
Tejun Heoa797bfc2013-12-11 14:11:57 -0500229 * mutex_lock(kernfs_mutex)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500230 *
231 * RETURNS:
232 * 0 on susccess -EEXIST on failure.
233 */
Tejun Heoc637b8a2013-12-11 14:11:58 -0500234static int kernfs_link_sibling(struct kernfs_node *kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500235{
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500236 struct rb_node **node = &kn->parent->dir.children.rb_node;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500237 struct rb_node *parent = NULL;
238
Tejun Heofd7b9f72013-11-28 14:54:33 -0500239 while (*node) {
Tejun Heo324a56e2013-12-11 14:11:53 -0500240 struct kernfs_node *pos;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500241 int result;
242
Tejun Heo324a56e2013-12-11 14:11:53 -0500243 pos = rb_to_kn(*node);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500244 parent = *node;
Tejun Heoc637b8a2013-12-11 14:11:58 -0500245 result = kernfs_sd_compare(kn, pos);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500246 if (result < 0)
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500247 node = &pos->rb.rb_left;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500248 else if (result > 0)
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500249 node = &pos->rb.rb_right;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500250 else
251 return -EEXIST;
252 }
Jianyu Zhanc1befb82014-04-17 17:52:10 +0800253
Tejun Heofd7b9f72013-11-28 14:54:33 -0500254 /* add new node and rebalance the tree */
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500255 rb_link_node(&kn->rb, parent, node);
256 rb_insert_color(&kn->rb, &kn->parent->dir.children);
Jianyu Zhanc1befb82014-04-17 17:52:10 +0800257
258 /* successfully added, account subdir number */
259 if (kernfs_type(kn) == KERNFS_DIR)
260 kn->parent->dir.subdirs++;
261
Tejun Heofd7b9f72013-11-28 14:54:33 -0500262 return 0;
263}
264
265/**
Tejun Heoc637b8a2013-12-11 14:11:58 -0500266 * kernfs_unlink_sibling - unlink kernfs_node from sibling rbtree
Tejun Heo324a56e2013-12-11 14:11:53 -0500267 * @kn: kernfs_node of interest
Tejun Heofd7b9f72013-11-28 14:54:33 -0500268 *
Tejun Heo35beab02014-02-03 14:02:56 -0500269 * Try to unlink @kn from its sibling rbtree which starts from
270 * kn->parent->dir.children. Returns %true if @kn was actually
271 * removed, %false if @kn wasn't on the rbtree.
Tejun Heofd7b9f72013-11-28 14:54:33 -0500272 *
273 * Locking:
Tejun Heoa797bfc2013-12-11 14:11:57 -0500274 * mutex_lock(kernfs_mutex)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500275 */
Tejun Heo35beab02014-02-03 14:02:56 -0500276static bool kernfs_unlink_sibling(struct kernfs_node *kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500277{
Tejun Heo35beab02014-02-03 14:02:56 -0500278 if (RB_EMPTY_NODE(&kn->rb))
279 return false;
280
Tejun Heodf23fc32013-12-11 14:11:56 -0500281 if (kernfs_type(kn) == KERNFS_DIR)
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500282 kn->parent->dir.subdirs--;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500283
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500284 rb_erase(&kn->rb, &kn->parent->dir.children);
Tejun Heo35beab02014-02-03 14:02:56 -0500285 RB_CLEAR_NODE(&kn->rb);
286 return true;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500287}
288
289/**
Tejun Heoc637b8a2013-12-11 14:11:58 -0500290 * kernfs_get_active - get an active reference to kernfs_node
Tejun Heo324a56e2013-12-11 14:11:53 -0500291 * @kn: kernfs_node to get an active reference to
Tejun Heofd7b9f72013-11-28 14:54:33 -0500292 *
Tejun Heo324a56e2013-12-11 14:11:53 -0500293 * Get an active reference of @kn. This function is noop if @kn
Tejun Heofd7b9f72013-11-28 14:54:33 -0500294 * is NULL.
295 *
296 * RETURNS:
Tejun Heo324a56e2013-12-11 14:11:53 -0500297 * Pointer to @kn on success, NULL on failure.
Tejun Heofd7b9f72013-11-28 14:54:33 -0500298 */
Tejun Heoc637b8a2013-12-11 14:11:58 -0500299struct kernfs_node *kernfs_get_active(struct kernfs_node *kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500300{
Tejun Heo324a56e2013-12-11 14:11:53 -0500301 if (unlikely(!kn))
Tejun Heofd7b9f72013-11-28 14:54:33 -0500302 return NULL;
303
Greg Kroah-Hartmanf4b3e632014-01-13 14:13:39 -0800304 if (!atomic_inc_unless_negative(&kn->active))
305 return NULL;
306
Tejun Heo182fd642014-02-03 14:02:59 -0500307 if (kernfs_lockdep(kn))
Tejun Heo324a56e2013-12-11 14:11:53 -0500308 rwsem_acquire_read(&kn->dep_map, 0, 1, _RET_IP_);
Greg Kroah-Hartmanf4b3e632014-01-13 14:13:39 -0800309 return kn;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500310}
311
312/**
Tejun Heoc637b8a2013-12-11 14:11:58 -0500313 * kernfs_put_active - put an active reference to kernfs_node
Tejun Heo324a56e2013-12-11 14:11:53 -0500314 * @kn: kernfs_node to put an active reference to
Tejun Heofd7b9f72013-11-28 14:54:33 -0500315 *
Tejun Heo324a56e2013-12-11 14:11:53 -0500316 * Put an active reference to @kn. This function is noop if @kn
Tejun Heofd7b9f72013-11-28 14:54:33 -0500317 * is NULL.
318 */
Tejun Heoc637b8a2013-12-11 14:11:58 -0500319void kernfs_put_active(struct kernfs_node *kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500320{
Tejun Heoabd54f02014-02-03 14:02:55 -0500321 struct kernfs_root *root = kernfs_root(kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500322 int v;
323
Tejun Heo324a56e2013-12-11 14:11:53 -0500324 if (unlikely(!kn))
Tejun Heofd7b9f72013-11-28 14:54:33 -0500325 return;
326
Tejun Heo182fd642014-02-03 14:02:59 -0500327 if (kernfs_lockdep(kn))
Tejun Heo324a56e2013-12-11 14:11:53 -0500328 rwsem_release(&kn->dep_map, 1, _RET_IP_);
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500329 v = atomic_dec_return(&kn->active);
Tejun Heodf23fc32013-12-11 14:11:56 -0500330 if (likely(v != KN_DEACTIVATED_BIAS))
Tejun Heofd7b9f72013-11-28 14:54:33 -0500331 return;
332
Tejun Heoabd54f02014-02-03 14:02:55 -0500333 wake_up_all(&root->deactivate_waitq);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500334}
335
336/**
Tejun Heo81c173c2014-02-03 14:03:00 -0500337 * kernfs_drain - drain kernfs_node
338 * @kn: kernfs_node to drain
Tejun Heofd7b9f72013-11-28 14:54:33 -0500339 *
Tejun Heo81c173c2014-02-03 14:03:00 -0500340 * Drain existing usages and nuke all existing mmaps of @kn. Mutiple
341 * removers may invoke this function concurrently on @kn and all will
342 * return after draining is complete.
Tejun Heofd7b9f72013-11-28 14:54:33 -0500343 */
Tejun Heo81c173c2014-02-03 14:03:00 -0500344static void kernfs_drain(struct kernfs_node *kn)
Tejun Heo35beab02014-02-03 14:02:56 -0500345 __releases(&kernfs_mutex) __acquires(&kernfs_mutex)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500346{
Tejun Heoabd54f02014-02-03 14:02:55 -0500347 struct kernfs_root *root = kernfs_root(kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500348
Tejun Heo35beab02014-02-03 14:02:56 -0500349 lockdep_assert_held(&kernfs_mutex);
Tejun Heo81c173c2014-02-03 14:03:00 -0500350 WARN_ON_ONCE(kernfs_active(kn));
Tejun Heo35beab02014-02-03 14:02:56 -0500351
352 mutex_unlock(&kernfs_mutex);
353
Tejun Heo182fd642014-02-03 14:02:59 -0500354 if (kernfs_lockdep(kn)) {
Tejun Heoa6607932014-02-03 14:02:54 -0500355 rwsem_acquire(&kn->dep_map, 0, 0, _RET_IP_);
Tejun Heo35beab02014-02-03 14:02:56 -0500356 if (atomic_read(&kn->active) != KN_DEACTIVATED_BIAS)
357 lock_contended(&kn->dep_map, _RET_IP_);
358 }
Greg Kroah-Hartman08901472014-01-13 14:39:52 -0800359
Tejun Heo35beab02014-02-03 14:02:56 -0500360 /* but everyone should wait for draining */
Tejun Heoabd54f02014-02-03 14:02:55 -0500361 wait_event(root->deactivate_waitq,
362 atomic_read(&kn->active) == KN_DEACTIVATED_BIAS);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500363
Tejun Heo182fd642014-02-03 14:02:59 -0500364 if (kernfs_lockdep(kn)) {
Tejun Heoa6607932014-02-03 14:02:54 -0500365 lock_acquired(&kn->dep_map, _RET_IP_);
366 rwsem_release(&kn->dep_map, 1, _RET_IP_);
367 }
Tejun Heo35beab02014-02-03 14:02:56 -0500368
Tejun Heoccf02aa2014-02-03 14:02:57 -0500369 kernfs_unmap_bin_file(kn);
370
Tejun Heo35beab02014-02-03 14:02:56 -0500371 mutex_lock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500372}
373
Tejun Heofd7b9f72013-11-28 14:54:33 -0500374/**
Tejun Heo324a56e2013-12-11 14:11:53 -0500375 * kernfs_get - get a reference count on a kernfs_node
376 * @kn: the target kernfs_node
Tejun Heofd7b9f72013-11-28 14:54:33 -0500377 */
Tejun Heo324a56e2013-12-11 14:11:53 -0500378void kernfs_get(struct kernfs_node *kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500379{
Tejun Heo324a56e2013-12-11 14:11:53 -0500380 if (kn) {
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500381 WARN_ON(!atomic_read(&kn->count));
382 atomic_inc(&kn->count);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500383 }
384}
385EXPORT_SYMBOL_GPL(kernfs_get);
386
387/**
Tejun Heo324a56e2013-12-11 14:11:53 -0500388 * kernfs_put - put a reference count on a kernfs_node
389 * @kn: the target kernfs_node
Tejun Heofd7b9f72013-11-28 14:54:33 -0500390 *
Tejun Heo324a56e2013-12-11 14:11:53 -0500391 * Put a reference count of @kn and destroy it if it reached zero.
Tejun Heofd7b9f72013-11-28 14:54:33 -0500392 */
Tejun Heo324a56e2013-12-11 14:11:53 -0500393void kernfs_put(struct kernfs_node *kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500394{
Tejun Heo324a56e2013-12-11 14:11:53 -0500395 struct kernfs_node *parent;
Tejun Heoba7443b2013-11-28 14:54:40 -0500396 struct kernfs_root *root;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500397
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500398 if (!kn || !atomic_dec_and_test(&kn->count))
Tejun Heofd7b9f72013-11-28 14:54:33 -0500399 return;
Tejun Heo324a56e2013-12-11 14:11:53 -0500400 root = kernfs_root(kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500401 repeat:
Tejun Heo81c173c2014-02-03 14:03:00 -0500402 /*
403 * Moving/renaming is always done while holding reference.
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500404 * kn->parent won't change beneath us.
Tejun Heofd7b9f72013-11-28 14:54:33 -0500405 */
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500406 parent = kn->parent;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500407
Tejun Heo81c173c2014-02-03 14:03:00 -0500408 WARN_ONCE(atomic_read(&kn->active) != KN_DEACTIVATED_BIAS,
409 "kernfs_put: %s/%s: released with incorrect active_ref %d\n",
410 parent ? parent->name : "", kn->name, atomic_read(&kn->active));
Tejun Heofd7b9f72013-11-28 14:54:33 -0500411
Tejun Heodf23fc32013-12-11 14:11:56 -0500412 if (kernfs_type(kn) == KERNFS_LINK)
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500413 kernfs_put(kn->symlink.target_kn);
Tejun Heodfeb07502015-02-13 14:36:31 -0800414
415 kfree_const(kn->name);
416
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500417 if (kn->iattr) {
418 if (kn->iattr->ia_secdata)
419 security_release_secctx(kn->iattr->ia_secdata,
420 kn->iattr->ia_secdata_len);
421 simple_xattrs_free(&kn->iattr->xattrs);
Tejun Heo23223922013-11-23 17:40:02 -0500422 }
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500423 kfree(kn->iattr);
424 ida_simple_remove(&root->ino_ida, kn->ino);
Tejun Heoa797bfc2013-12-11 14:11:57 -0500425 kmem_cache_free(kernfs_node_cache, kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500426
Tejun Heo324a56e2013-12-11 14:11:53 -0500427 kn = parent;
428 if (kn) {
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500429 if (atomic_dec_and_test(&kn->count))
Tejun Heoba7443b2013-11-28 14:54:40 -0500430 goto repeat;
431 } else {
Tejun Heo324a56e2013-12-11 14:11:53 -0500432 /* just released the root kn, free @root too */
Tejun Heobc755552013-11-28 14:54:41 -0500433 ida_destroy(&root->ino_ida);
Tejun Heoba7443b2013-11-28 14:54:40 -0500434 kfree(root);
435 }
Tejun Heofd7b9f72013-11-28 14:54:33 -0500436}
437EXPORT_SYMBOL_GPL(kernfs_put);
438
Tejun Heoc637b8a2013-12-11 14:11:58 -0500439static int kernfs_dop_revalidate(struct dentry *dentry, unsigned int flags)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500440{
Tejun Heo324a56e2013-12-11 14:11:53 -0500441 struct kernfs_node *kn;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500442
443 if (flags & LOOKUP_RCU)
444 return -ECHILD;
445
Tejun Heo19bbb922013-12-11 16:02:59 -0500446 /* Always perform fresh lookup for negatives */
447 if (!dentry->d_inode)
448 goto out_bad_unlocked;
449
Tejun Heo324a56e2013-12-11 14:11:53 -0500450 kn = dentry->d_fsdata;
Tejun Heoa797bfc2013-12-11 14:11:57 -0500451 mutex_lock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500452
Tejun Heo81c173c2014-02-03 14:03:00 -0500453 /* The kernfs node has been deactivated */
454 if (!kernfs_active(kn))
Tejun Heofd7b9f72013-11-28 14:54:33 -0500455 goto out_bad;
456
Tejun Heoc637b8a2013-12-11 14:11:58 -0500457 /* The kernfs node has been moved? */
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500458 if (dentry->d_parent->d_fsdata != kn->parent)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500459 goto out_bad;
460
Tejun Heoc637b8a2013-12-11 14:11:58 -0500461 /* The kernfs node has been renamed */
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500462 if (strcmp(dentry->d_name.name, kn->name) != 0)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500463 goto out_bad;
464
Tejun Heoc637b8a2013-12-11 14:11:58 -0500465 /* The kernfs node has been moved to a different namespace */
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500466 if (kn->parent && kernfs_ns_enabled(kn->parent) &&
Tejun Heoc525aad2013-12-11 14:11:55 -0500467 kernfs_info(dentry->d_sb)->ns != kn->ns)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500468 goto out_bad;
469
Tejun Heoa797bfc2013-12-11 14:11:57 -0500470 mutex_unlock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500471 return 1;
472out_bad:
Tejun Heoa797bfc2013-12-11 14:11:57 -0500473 mutex_unlock(&kernfs_mutex);
Tejun Heo19bbb922013-12-11 16:02:59 -0500474out_bad_unlocked:
Tejun Heofd7b9f72013-11-28 14:54:33 -0500475 return 0;
476}
477
Tejun Heoc637b8a2013-12-11 14:11:58 -0500478static void kernfs_dop_release(struct dentry *dentry)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500479{
480 kernfs_put(dentry->d_fsdata);
481}
482
Tejun Heoa797bfc2013-12-11 14:11:57 -0500483const struct dentry_operations kernfs_dops = {
Tejun Heoc637b8a2013-12-11 14:11:58 -0500484 .d_revalidate = kernfs_dop_revalidate,
Tejun Heoc637b8a2013-12-11 14:11:58 -0500485 .d_release = kernfs_dop_release,
Tejun Heofd7b9f72013-11-28 14:54:33 -0500486};
487
Tejun Heo0c23b222014-02-03 14:09:15 -0500488/**
489 * kernfs_node_from_dentry - determine kernfs_node associated with a dentry
490 * @dentry: the dentry in question
491 *
492 * Return the kernfs_node associated with @dentry. If @dentry is not a
493 * kernfs one, %NULL is returned.
494 *
495 * While the returned kernfs_node will stay accessible as long as @dentry
496 * is accessible, the returned node can be in any state and the caller is
497 * fully responsible for determining what's accessible.
498 */
499struct kernfs_node *kernfs_node_from_dentry(struct dentry *dentry)
500{
Li Zefanf41c5932014-02-14 16:57:27 +0800501 if (dentry->d_sb->s_op == &kernfs_sops)
Tejun Heo0c23b222014-02-03 14:09:15 -0500502 return dentry->d_fsdata;
503 return NULL;
504}
505
Tejun Heodb4aad22014-01-17 09:58:25 -0500506static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root,
507 const char *name, umode_t mode,
508 unsigned flags)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500509{
Tejun Heo324a56e2013-12-11 14:11:53 -0500510 struct kernfs_node *kn;
Tejun Heobc755552013-11-28 14:54:41 -0500511 int ret;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500512
Tejun Heodfeb07502015-02-13 14:36:31 -0800513 name = kstrdup_const(name, GFP_KERNEL);
514 if (!name)
515 return NULL;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500516
Tejun Heoa797bfc2013-12-11 14:11:57 -0500517 kn = kmem_cache_zalloc(kernfs_node_cache, GFP_KERNEL);
Tejun Heo324a56e2013-12-11 14:11:53 -0500518 if (!kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500519 goto err_out1;
520
Tejun Heobc755552013-11-28 14:54:41 -0500521 ret = ida_simple_get(&root->ino_ida, 1, 0, GFP_KERNEL);
522 if (ret < 0)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500523 goto err_out2;
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500524 kn->ino = ret;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500525
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500526 atomic_set(&kn->count, 1);
Tejun Heo81c173c2014-02-03 14:03:00 -0500527 atomic_set(&kn->active, KN_DEACTIVATED_BIAS);
Tejun Heo35beab02014-02-03 14:02:56 -0500528 RB_CLEAR_NODE(&kn->rb);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500529
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500530 kn->name = name;
531 kn->mode = mode;
Tejun Heo81c173c2014-02-03 14:03:00 -0500532 kn->flags = flags;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500533
Tejun Heo324a56e2013-12-11 14:11:53 -0500534 return kn;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500535
536 err_out2:
Tejun Heoa797bfc2013-12-11 14:11:57 -0500537 kmem_cache_free(kernfs_node_cache, kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500538 err_out1:
Tejun Heodfeb07502015-02-13 14:36:31 -0800539 kfree_const(name);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500540 return NULL;
541}
542
Tejun Heodb4aad22014-01-17 09:58:25 -0500543struct kernfs_node *kernfs_new_node(struct kernfs_node *parent,
544 const char *name, umode_t mode,
545 unsigned flags)
546{
547 struct kernfs_node *kn;
548
549 kn = __kernfs_new_node(kernfs_root(parent), name, mode, flags);
550 if (kn) {
551 kernfs_get(parent);
552 kn->parent = parent;
553 }
554 return kn;
555}
556
Tejun Heofd7b9f72013-11-28 14:54:33 -0500557/**
Tejun Heoc637b8a2013-12-11 14:11:58 -0500558 * kernfs_add_one - add kernfs_node to parent without warning
Tejun Heo324a56e2013-12-11 14:11:53 -0500559 * @kn: kernfs_node to be added
Tejun Heofd7b9f72013-11-28 14:54:33 -0500560 *
Tejun Heodb4aad22014-01-17 09:58:25 -0500561 * The caller must already have initialized @kn->parent. This
562 * function increments nlink of the parent's inode if @kn is a
563 * directory and link into the children list of the parent.
Tejun Heofd7b9f72013-11-28 14:54:33 -0500564 *
Tejun Heofd7b9f72013-11-28 14:54:33 -0500565 * RETURNS:
566 * 0 on success, -EEXIST if entry with the given name already
567 * exists.
568 */
Tejun Heo988cd7a2014-02-03 14:02:58 -0500569int kernfs_add_one(struct kernfs_node *kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500570{
Tejun Heodb4aad22014-01-17 09:58:25 -0500571 struct kernfs_node *parent = kn->parent;
Tejun Heoc525aad2013-12-11 14:11:55 -0500572 struct kernfs_iattrs *ps_iattr;
Tejun Heo988cd7a2014-02-03 14:02:58 -0500573 bool has_ns;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500574 int ret;
575
Tejun Heo988cd7a2014-02-03 14:02:58 -0500576 mutex_lock(&kernfs_mutex);
577
578 ret = -EINVAL;
579 has_ns = kernfs_ns_enabled(parent);
580 if (WARN(has_ns != (bool)kn->ns, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n",
581 has_ns ? "required" : "invalid", parent->name, kn->name))
582 goto out_unlock;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500583
Tejun Heodf23fc32013-12-11 14:11:56 -0500584 if (kernfs_type(parent) != KERNFS_DIR)
Tejun Heo988cd7a2014-02-03 14:02:58 -0500585 goto out_unlock;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500586
Tejun Heo988cd7a2014-02-03 14:02:58 -0500587 ret = -ENOENT;
Tejun Heod35258e2014-02-03 14:09:12 -0500588 if ((parent->flags & KERNFS_ACTIVATED) && !kernfs_active(parent))
Tejun Heo988cd7a2014-02-03 14:02:58 -0500589 goto out_unlock;
Greg Kroah-Hartman798c75a2014-01-13 14:36:03 -0800590
Tejun Heoc637b8a2013-12-11 14:11:58 -0500591 kn->hash = kernfs_name_hash(kn->name, kn->ns);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500592
Tejun Heoc637b8a2013-12-11 14:11:58 -0500593 ret = kernfs_link_sibling(kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500594 if (ret)
Tejun Heo988cd7a2014-02-03 14:02:58 -0500595 goto out_unlock;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500596
597 /* Update timestamps on the parent */
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500598 ps_iattr = parent->iattr;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500599 if (ps_iattr) {
600 struct iattr *ps_iattrs = &ps_iattr->ia_iattr;
601 ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME;
602 }
603
Tejun Heod35258e2014-02-03 14:09:12 -0500604 mutex_unlock(&kernfs_mutex);
605
606 /*
607 * Activate the new node unless CREATE_DEACTIVATED is requested.
608 * If not activated here, the kernfs user is responsible for
609 * activating the node with kernfs_activate(). A node which hasn't
610 * been activated is not visible to userland and its removal won't
611 * trigger deactivation.
612 */
613 if (!(kernfs_root(kn)->flags & KERNFS_ROOT_CREATE_DEACTIVATED))
614 kernfs_activate(kn);
615 return 0;
616
Tejun Heo988cd7a2014-02-03 14:02:58 -0500617out_unlock:
Tejun Heoa797bfc2013-12-11 14:11:57 -0500618 mutex_unlock(&kernfs_mutex);
Tejun Heo988cd7a2014-02-03 14:02:58 -0500619 return ret;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500620}
621
622/**
Tejun Heo324a56e2013-12-11 14:11:53 -0500623 * kernfs_find_ns - find kernfs_node with the given name
624 * @parent: kernfs_node to search under
Tejun Heofd7b9f72013-11-28 14:54:33 -0500625 * @name: name to look for
626 * @ns: the namespace tag to use
627 *
Tejun Heo324a56e2013-12-11 14:11:53 -0500628 * Look for kernfs_node with name @name under @parent. Returns pointer to
629 * the found kernfs_node on success, %NULL on failure.
Tejun Heofd7b9f72013-11-28 14:54:33 -0500630 */
Tejun Heo324a56e2013-12-11 14:11:53 -0500631static struct kernfs_node *kernfs_find_ns(struct kernfs_node *parent,
632 const unsigned char *name,
633 const void *ns)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500634{
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500635 struct rb_node *node = parent->dir.children.rb_node;
Tejun Heoac9bba02013-11-29 17:19:09 -0500636 bool has_ns = kernfs_ns_enabled(parent);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500637 unsigned int hash;
638
Tejun Heoa797bfc2013-12-11 14:11:57 -0500639 lockdep_assert_held(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500640
641 if (has_ns != (bool)ns) {
Tejun Heoc637b8a2013-12-11 14:11:58 -0500642 WARN(1, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n",
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500643 has_ns ? "required" : "invalid", parent->name, name);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500644 return NULL;
645 }
646
Tejun Heoc637b8a2013-12-11 14:11:58 -0500647 hash = kernfs_name_hash(name, ns);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500648 while (node) {
Tejun Heo324a56e2013-12-11 14:11:53 -0500649 struct kernfs_node *kn;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500650 int result;
651
Tejun Heo324a56e2013-12-11 14:11:53 -0500652 kn = rb_to_kn(node);
Tejun Heoc637b8a2013-12-11 14:11:58 -0500653 result = kernfs_name_compare(hash, name, ns, kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500654 if (result < 0)
655 node = node->rb_left;
656 else if (result > 0)
657 node = node->rb_right;
658 else
Tejun Heo324a56e2013-12-11 14:11:53 -0500659 return kn;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500660 }
661 return NULL;
662}
663
664/**
Tejun Heo324a56e2013-12-11 14:11:53 -0500665 * kernfs_find_and_get_ns - find and get kernfs_node with the given name
666 * @parent: kernfs_node to search under
Tejun Heofd7b9f72013-11-28 14:54:33 -0500667 * @name: name to look for
668 * @ns: the namespace tag to use
669 *
Tejun Heo324a56e2013-12-11 14:11:53 -0500670 * Look for kernfs_node with name @name under @parent and get a reference
Tejun Heofd7b9f72013-11-28 14:54:33 -0500671 * if found. This function may sleep and returns pointer to the found
Tejun Heo324a56e2013-12-11 14:11:53 -0500672 * kernfs_node on success, %NULL on failure.
Tejun Heofd7b9f72013-11-28 14:54:33 -0500673 */
Tejun Heo324a56e2013-12-11 14:11:53 -0500674struct kernfs_node *kernfs_find_and_get_ns(struct kernfs_node *parent,
675 const char *name, const void *ns)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500676{
Tejun Heo324a56e2013-12-11 14:11:53 -0500677 struct kernfs_node *kn;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500678
Tejun Heoa797bfc2013-12-11 14:11:57 -0500679 mutex_lock(&kernfs_mutex);
Tejun Heo324a56e2013-12-11 14:11:53 -0500680 kn = kernfs_find_ns(parent, name, ns);
681 kernfs_get(kn);
Tejun Heoa797bfc2013-12-11 14:11:57 -0500682 mutex_unlock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500683
Tejun Heo324a56e2013-12-11 14:11:53 -0500684 return kn;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500685}
686EXPORT_SYMBOL_GPL(kernfs_find_and_get_ns);
687
688/**
Tejun Heoba7443b2013-11-28 14:54:40 -0500689 * kernfs_create_root - create a new kernfs hierarchy
Tejun Heo90c07c82014-02-03 14:09:09 -0500690 * @scops: optional syscall operations for the hierarchy
Tejun Heod35258e2014-02-03 14:09:12 -0500691 * @flags: KERNFS_ROOT_* flags
Tejun Heoba7443b2013-11-28 14:54:40 -0500692 * @priv: opaque data associated with the new directory
693 *
694 * Returns the root of the new hierarchy on success, ERR_PTR() value on
695 * failure.
696 */
Tejun Heo90c07c82014-02-03 14:09:09 -0500697struct kernfs_root *kernfs_create_root(struct kernfs_syscall_ops *scops,
Tejun Heod35258e2014-02-03 14:09:12 -0500698 unsigned int flags, void *priv)
Tejun Heoba7443b2013-11-28 14:54:40 -0500699{
700 struct kernfs_root *root;
Tejun Heo324a56e2013-12-11 14:11:53 -0500701 struct kernfs_node *kn;
Tejun Heoba7443b2013-11-28 14:54:40 -0500702
703 root = kzalloc(sizeof(*root), GFP_KERNEL);
704 if (!root)
705 return ERR_PTR(-ENOMEM);
706
Tejun Heobc755552013-11-28 14:54:41 -0500707 ida_init(&root->ino_ida);
Tejun Heo7d568a82014-04-09 11:07:30 -0400708 INIT_LIST_HEAD(&root->supers);
Tejun Heobc755552013-11-28 14:54:41 -0500709
Tejun Heodb4aad22014-01-17 09:58:25 -0500710 kn = __kernfs_new_node(root, "", S_IFDIR | S_IRUGO | S_IXUGO,
711 KERNFS_DIR);
Tejun Heo324a56e2013-12-11 14:11:53 -0500712 if (!kn) {
Tejun Heobc755552013-11-28 14:54:41 -0500713 ida_destroy(&root->ino_ida);
Tejun Heoba7443b2013-11-28 14:54:40 -0500714 kfree(root);
715 return ERR_PTR(-ENOMEM);
716 }
717
Tejun Heo324a56e2013-12-11 14:11:53 -0500718 kn->priv = priv;
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500719 kn->dir.root = root;
Tejun Heoba7443b2013-11-28 14:54:40 -0500720
Tejun Heo90c07c82014-02-03 14:09:09 -0500721 root->syscall_ops = scops;
Tejun Heod35258e2014-02-03 14:09:12 -0500722 root->flags = flags;
Tejun Heo324a56e2013-12-11 14:11:53 -0500723 root->kn = kn;
Tejun Heoabd54f02014-02-03 14:02:55 -0500724 init_waitqueue_head(&root->deactivate_waitq);
Tejun Heoba7443b2013-11-28 14:54:40 -0500725
Tejun Heod35258e2014-02-03 14:09:12 -0500726 if (!(root->flags & KERNFS_ROOT_CREATE_DEACTIVATED))
727 kernfs_activate(kn);
728
Tejun Heoba7443b2013-11-28 14:54:40 -0500729 return root;
730}
731
732/**
733 * kernfs_destroy_root - destroy a kernfs hierarchy
734 * @root: root of the hierarchy to destroy
735 *
736 * Destroy the hierarchy anchored at @root by removing all existing
737 * directories and destroying @root.
738 */
739void kernfs_destroy_root(struct kernfs_root *root)
740{
Tejun Heo324a56e2013-12-11 14:11:53 -0500741 kernfs_remove(root->kn); /* will also free @root */
Tejun Heoba7443b2013-11-28 14:54:40 -0500742}
743
744/**
Tejun Heofd7b9f72013-11-28 14:54:33 -0500745 * kernfs_create_dir_ns - create a directory
746 * @parent: parent in which to create a new directory
747 * @name: name of the new directory
Tejun Heobb8b9d092013-12-11 16:02:55 -0500748 * @mode: mode of the new directory
Tejun Heofd7b9f72013-11-28 14:54:33 -0500749 * @priv: opaque data associated with the new directory
750 * @ns: optional namespace tag of the directory
751 *
752 * Returns the created node on success, ERR_PTR() value on failure.
753 */
Tejun Heo324a56e2013-12-11 14:11:53 -0500754struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent,
Tejun Heobb8b9d092013-12-11 16:02:55 -0500755 const char *name, umode_t mode,
756 void *priv, const void *ns)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500757{
Tejun Heo324a56e2013-12-11 14:11:53 -0500758 struct kernfs_node *kn;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500759 int rc;
760
761 /* allocate */
Tejun Heodb4aad22014-01-17 09:58:25 -0500762 kn = kernfs_new_node(parent, name, mode | S_IFDIR, KERNFS_DIR);
Tejun Heo324a56e2013-12-11 14:11:53 -0500763 if (!kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500764 return ERR_PTR(-ENOMEM);
765
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500766 kn->dir.root = parent->dir.root;
767 kn->ns = ns;
Tejun Heo324a56e2013-12-11 14:11:53 -0500768 kn->priv = priv;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500769
770 /* link in */
Tejun Heo988cd7a2014-02-03 14:02:58 -0500771 rc = kernfs_add_one(kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500772 if (!rc)
Tejun Heo324a56e2013-12-11 14:11:53 -0500773 return kn;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500774
Tejun Heo324a56e2013-12-11 14:11:53 -0500775 kernfs_put(kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500776 return ERR_PTR(rc);
777}
778
Tejun Heoc637b8a2013-12-11 14:11:58 -0500779static struct dentry *kernfs_iop_lookup(struct inode *dir,
780 struct dentry *dentry,
781 unsigned int flags)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500782{
Tejun Heo19bbb922013-12-11 16:02:59 -0500783 struct dentry *ret;
Tejun Heo324a56e2013-12-11 14:11:53 -0500784 struct kernfs_node *parent = dentry->d_parent->d_fsdata;
785 struct kernfs_node *kn;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500786 struct inode *inode;
787 const void *ns = NULL;
788
Tejun Heoa797bfc2013-12-11 14:11:57 -0500789 mutex_lock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500790
Tejun Heo324a56e2013-12-11 14:11:53 -0500791 if (kernfs_ns_enabled(parent))
Tejun Heoc525aad2013-12-11 14:11:55 -0500792 ns = kernfs_info(dir->i_sb)->ns;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500793
Tejun Heo324a56e2013-12-11 14:11:53 -0500794 kn = kernfs_find_ns(parent, dentry->d_name.name, ns);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500795
796 /* no such entry */
Tejun Heob9c9dad2014-02-03 14:09:11 -0500797 if (!kn || !kernfs_active(kn)) {
Tejun Heo19bbb922013-12-11 16:02:59 -0500798 ret = NULL;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500799 goto out_unlock;
800 }
Tejun Heo324a56e2013-12-11 14:11:53 -0500801 kernfs_get(kn);
802 dentry->d_fsdata = kn;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500803
804 /* attach dentry and inode */
Tejun Heoc637b8a2013-12-11 14:11:58 -0500805 inode = kernfs_get_inode(dir->i_sb, kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500806 if (!inode) {
807 ret = ERR_PTR(-ENOMEM);
808 goto out_unlock;
809 }
810
811 /* instantiate and hash dentry */
Al Viro41d28bc2014-10-12 22:24:21 -0400812 ret = d_splice_alias(inode, dentry);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500813 out_unlock:
Tejun Heoa797bfc2013-12-11 14:11:57 -0500814 mutex_unlock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500815 return ret;
816}
817
Tejun Heo80b9bbe2013-12-11 16:03:00 -0500818static int kernfs_iop_mkdir(struct inode *dir, struct dentry *dentry,
819 umode_t mode)
820{
821 struct kernfs_node *parent = dir->i_private;
Tejun Heo90c07c82014-02-03 14:09:09 -0500822 struct kernfs_syscall_ops *scops = kernfs_root(parent)->syscall_ops;
Tejun Heo07c75302014-02-03 14:09:08 -0500823 int ret;
Tejun Heo80b9bbe2013-12-11 16:03:00 -0500824
Tejun Heo90c07c82014-02-03 14:09:09 -0500825 if (!scops || !scops->mkdir)
Tejun Heo80b9bbe2013-12-11 16:03:00 -0500826 return -EPERM;
827
Tejun Heo07c75302014-02-03 14:09:08 -0500828 if (!kernfs_get_active(parent))
829 return -ENODEV;
830
Tejun Heo90c07c82014-02-03 14:09:09 -0500831 ret = scops->mkdir(parent, dentry->d_name.name, mode);
Tejun Heo07c75302014-02-03 14:09:08 -0500832
833 kernfs_put_active(parent);
834 return ret;
Tejun Heo80b9bbe2013-12-11 16:03:00 -0500835}
836
837static int kernfs_iop_rmdir(struct inode *dir, struct dentry *dentry)
838{
839 struct kernfs_node *kn = dentry->d_fsdata;
Tejun Heo90c07c82014-02-03 14:09:09 -0500840 struct kernfs_syscall_ops *scops = kernfs_root(kn)->syscall_ops;
Tejun Heo07c75302014-02-03 14:09:08 -0500841 int ret;
Tejun Heo80b9bbe2013-12-11 16:03:00 -0500842
Tejun Heo90c07c82014-02-03 14:09:09 -0500843 if (!scops || !scops->rmdir)
Tejun Heo80b9bbe2013-12-11 16:03:00 -0500844 return -EPERM;
845
Tejun Heo07c75302014-02-03 14:09:08 -0500846 if (!kernfs_get_active(kn))
847 return -ENODEV;
848
Tejun Heo90c07c82014-02-03 14:09:09 -0500849 ret = scops->rmdir(kn);
Tejun Heo07c75302014-02-03 14:09:08 -0500850
851 kernfs_put_active(kn);
852 return ret;
Tejun Heo80b9bbe2013-12-11 16:03:00 -0500853}
854
855static int kernfs_iop_rename(struct inode *old_dir, struct dentry *old_dentry,
856 struct inode *new_dir, struct dentry *new_dentry)
857{
858 struct kernfs_node *kn = old_dentry->d_fsdata;
859 struct kernfs_node *new_parent = new_dir->i_private;
Tejun Heo90c07c82014-02-03 14:09:09 -0500860 struct kernfs_syscall_ops *scops = kernfs_root(kn)->syscall_ops;
Tejun Heo07c75302014-02-03 14:09:08 -0500861 int ret;
Tejun Heo80b9bbe2013-12-11 16:03:00 -0500862
Tejun Heo90c07c82014-02-03 14:09:09 -0500863 if (!scops || !scops->rename)
Tejun Heo80b9bbe2013-12-11 16:03:00 -0500864 return -EPERM;
865
Tejun Heo07c75302014-02-03 14:09:08 -0500866 if (!kernfs_get_active(kn))
867 return -ENODEV;
868
869 if (!kernfs_get_active(new_parent)) {
870 kernfs_put_active(kn);
871 return -ENODEV;
872 }
873
Tejun Heo90c07c82014-02-03 14:09:09 -0500874 ret = scops->rename(kn, new_parent, new_dentry->d_name.name);
Tejun Heo07c75302014-02-03 14:09:08 -0500875
876 kernfs_put_active(new_parent);
877 kernfs_put_active(kn);
878 return ret;
Tejun Heo80b9bbe2013-12-11 16:03:00 -0500879}
880
Tejun Heoa797bfc2013-12-11 14:11:57 -0500881const struct inode_operations kernfs_dir_iops = {
Tejun Heoc637b8a2013-12-11 14:11:58 -0500882 .lookup = kernfs_iop_lookup,
883 .permission = kernfs_iop_permission,
884 .setattr = kernfs_iop_setattr,
885 .getattr = kernfs_iop_getattr,
886 .setxattr = kernfs_iop_setxattr,
887 .removexattr = kernfs_iop_removexattr,
888 .getxattr = kernfs_iop_getxattr,
889 .listxattr = kernfs_iop_listxattr,
Tejun Heo80b9bbe2013-12-11 16:03:00 -0500890
891 .mkdir = kernfs_iop_mkdir,
892 .rmdir = kernfs_iop_rmdir,
893 .rename = kernfs_iop_rename,
Tejun Heofd7b9f72013-11-28 14:54:33 -0500894};
895
Tejun Heoc637b8a2013-12-11 14:11:58 -0500896static struct kernfs_node *kernfs_leftmost_descendant(struct kernfs_node *pos)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500897{
Tejun Heo324a56e2013-12-11 14:11:53 -0500898 struct kernfs_node *last;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500899
900 while (true) {
901 struct rb_node *rbn;
902
903 last = pos;
904
Tejun Heodf23fc32013-12-11 14:11:56 -0500905 if (kernfs_type(pos) != KERNFS_DIR)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500906 break;
907
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500908 rbn = rb_first(&pos->dir.children);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500909 if (!rbn)
910 break;
911
Tejun Heo324a56e2013-12-11 14:11:53 -0500912 pos = rb_to_kn(rbn);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500913 }
914
915 return last;
916}
917
918/**
Tejun Heoc637b8a2013-12-11 14:11:58 -0500919 * kernfs_next_descendant_post - find the next descendant for post-order walk
Tejun Heofd7b9f72013-11-28 14:54:33 -0500920 * @pos: the current position (%NULL to initiate traversal)
Tejun Heo324a56e2013-12-11 14:11:53 -0500921 * @root: kernfs_node whose descendants to walk
Tejun Heofd7b9f72013-11-28 14:54:33 -0500922 *
923 * Find the next descendant to visit for post-order traversal of @root's
924 * descendants. @root is included in the iteration and the last node to be
925 * visited.
926 */
Tejun Heoc637b8a2013-12-11 14:11:58 -0500927static struct kernfs_node *kernfs_next_descendant_post(struct kernfs_node *pos,
928 struct kernfs_node *root)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500929{
930 struct rb_node *rbn;
931
Tejun Heoa797bfc2013-12-11 14:11:57 -0500932 lockdep_assert_held(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500933
934 /* if first iteration, visit leftmost descendant which may be root */
935 if (!pos)
Tejun Heoc637b8a2013-12-11 14:11:58 -0500936 return kernfs_leftmost_descendant(root);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500937
938 /* if we visited @root, we're done */
939 if (pos == root)
940 return NULL;
941
942 /* if there's an unvisited sibling, visit its leftmost descendant */
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500943 rbn = rb_next(&pos->rb);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500944 if (rbn)
Tejun Heoc637b8a2013-12-11 14:11:58 -0500945 return kernfs_leftmost_descendant(rb_to_kn(rbn));
Tejun Heofd7b9f72013-11-28 14:54:33 -0500946
947 /* no sibling left, visit parent */
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500948 return pos->parent;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500949}
950
Tejun Heod35258e2014-02-03 14:09:12 -0500951/**
952 * kernfs_activate - activate a node which started deactivated
953 * @kn: kernfs_node whose subtree is to be activated
954 *
955 * If the root has KERNFS_ROOT_CREATE_DEACTIVATED set, a newly created node
956 * needs to be explicitly activated. A node which hasn't been activated
957 * isn't visible to userland and deactivation is skipped during its
958 * removal. This is useful to construct atomic init sequences where
959 * creation of multiple nodes should either succeed or fail atomically.
960 *
961 * The caller is responsible for ensuring that this function is not called
962 * after kernfs_remove*() is invoked on @kn.
963 */
964void kernfs_activate(struct kernfs_node *kn)
965{
966 struct kernfs_node *pos;
967
968 mutex_lock(&kernfs_mutex);
969
970 pos = NULL;
971 while ((pos = kernfs_next_descendant_post(pos, kn))) {
972 if (!pos || (pos->flags & KERNFS_ACTIVATED))
973 continue;
974
975 WARN_ON_ONCE(pos->parent && RB_EMPTY_NODE(&pos->rb));
976 WARN_ON_ONCE(atomic_read(&pos->active) != KN_DEACTIVATED_BIAS);
977
978 atomic_sub(KN_DEACTIVATED_BIAS, &pos->active);
979 pos->flags |= KERNFS_ACTIVATED;
980 }
981
982 mutex_unlock(&kernfs_mutex);
983}
984
Tejun Heo988cd7a2014-02-03 14:02:58 -0500985static void __kernfs_remove(struct kernfs_node *kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500986{
Tejun Heo35beab02014-02-03 14:02:56 -0500987 struct kernfs_node *pos;
988
989 lockdep_assert_held(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500990
Tejun Heo6b0afc22014-02-03 14:03:01 -0500991 /*
992 * Short-circuit if non-root @kn has already finished removal.
993 * This is for kernfs_remove_self() which plays with active ref
994 * after removal.
995 */
996 if (!kn || (kn->parent && RB_EMPTY_NODE(&kn->rb)))
Greg Kroah-Hartmance9b4992014-01-13 13:50:31 -0800997 return;
998
Tejun Heoc637b8a2013-12-11 14:11:58 -0500999 pr_debug("kernfs %s: removing\n", kn->name);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001000
Tejun Heo81c173c2014-02-03 14:03:00 -05001001 /* prevent any new usage under @kn by deactivating all nodes */
Tejun Heo35beab02014-02-03 14:02:56 -05001002 pos = NULL;
1003 while ((pos = kernfs_next_descendant_post(pos, kn)))
Tejun Heo81c173c2014-02-03 14:03:00 -05001004 if (kernfs_active(pos))
1005 atomic_add(KN_DEACTIVATED_BIAS, &pos->active);
Tejun Heo35beab02014-02-03 14:02:56 -05001006
1007 /* deactivate and unlink the subtree node-by-node */
Tejun Heofd7b9f72013-11-28 14:54:33 -05001008 do {
Tejun Heo35beab02014-02-03 14:02:56 -05001009 pos = kernfs_leftmost_descendant(kn);
1010
1011 /*
Tejun Heo81c173c2014-02-03 14:03:00 -05001012 * kernfs_drain() drops kernfs_mutex temporarily and @pos's
1013 * base ref could have been put by someone else by the time
1014 * the function returns. Make sure it doesn't go away
1015 * underneath us.
Tejun Heo35beab02014-02-03 14:02:56 -05001016 */
1017 kernfs_get(pos);
1018
Tejun Heod35258e2014-02-03 14:09:12 -05001019 /*
1020 * Drain iff @kn was activated. This avoids draining and
1021 * its lockdep annotations for nodes which have never been
1022 * activated and allows embedding kernfs_remove() in create
1023 * error paths without worrying about draining.
1024 */
1025 if (kn->flags & KERNFS_ACTIVATED)
1026 kernfs_drain(pos);
1027 else
1028 WARN_ON_ONCE(atomic_read(&kn->active) != KN_DEACTIVATED_BIAS);
Tejun Heo35beab02014-02-03 14:02:56 -05001029
1030 /*
1031 * kernfs_unlink_sibling() succeeds once per node. Use it
1032 * to decide who's responsible for cleanups.
1033 */
1034 if (!pos->parent || kernfs_unlink_sibling(pos)) {
1035 struct kernfs_iattrs *ps_iattr =
1036 pos->parent ? pos->parent->iattr : NULL;
1037
1038 /* update timestamps on the parent */
1039 if (ps_iattr) {
1040 ps_iattr->ia_iattr.ia_ctime = CURRENT_TIME;
1041 ps_iattr->ia_iattr.ia_mtime = CURRENT_TIME;
1042 }
1043
Tejun Heo988cd7a2014-02-03 14:02:58 -05001044 kernfs_put(pos);
Tejun Heo35beab02014-02-03 14:02:56 -05001045 }
1046
1047 kernfs_put(pos);
1048 } while (pos != kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001049}
1050
1051/**
Tejun Heo324a56e2013-12-11 14:11:53 -05001052 * kernfs_remove - remove a kernfs_node recursively
1053 * @kn: the kernfs_node to remove
Tejun Heofd7b9f72013-11-28 14:54:33 -05001054 *
Tejun Heo324a56e2013-12-11 14:11:53 -05001055 * Remove @kn along with all its subdirectories and files.
Tejun Heofd7b9f72013-11-28 14:54:33 -05001056 */
Tejun Heo324a56e2013-12-11 14:11:53 -05001057void kernfs_remove(struct kernfs_node *kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -05001058{
Tejun Heo988cd7a2014-02-03 14:02:58 -05001059 mutex_lock(&kernfs_mutex);
1060 __kernfs_remove(kn);
1061 mutex_unlock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001062}
1063
1064/**
Tejun Heo6b0afc22014-02-03 14:03:01 -05001065 * kernfs_break_active_protection - break out of active protection
1066 * @kn: the self kernfs_node
1067 *
1068 * The caller must be running off of a kernfs operation which is invoked
1069 * with an active reference - e.g. one of kernfs_ops. Each invocation of
1070 * this function must also be matched with an invocation of
1071 * kernfs_unbreak_active_protection().
1072 *
1073 * This function releases the active reference of @kn the caller is
1074 * holding. Once this function is called, @kn may be removed at any point
1075 * and the caller is solely responsible for ensuring that the objects it
1076 * dereferences are accessible.
1077 */
1078void kernfs_break_active_protection(struct kernfs_node *kn)
1079{
1080 /*
1081 * Take out ourself out of the active ref dependency chain. If
1082 * we're called without an active ref, lockdep will complain.
1083 */
1084 kernfs_put_active(kn);
1085}
1086
1087/**
1088 * kernfs_unbreak_active_protection - undo kernfs_break_active_protection()
1089 * @kn: the self kernfs_node
1090 *
1091 * If kernfs_break_active_protection() was called, this function must be
1092 * invoked before finishing the kernfs operation. Note that while this
1093 * function restores the active reference, it doesn't and can't actually
1094 * restore the active protection - @kn may already or be in the process of
1095 * being removed. Once kernfs_break_active_protection() is invoked, that
1096 * protection is irreversibly gone for the kernfs operation instance.
1097 *
1098 * While this function may be called at any point after
1099 * kernfs_break_active_protection() is invoked, its most useful location
1100 * would be right before the enclosing kernfs operation returns.
1101 */
1102void kernfs_unbreak_active_protection(struct kernfs_node *kn)
1103{
1104 /*
1105 * @kn->active could be in any state; however, the increment we do
1106 * here will be undone as soon as the enclosing kernfs operation
1107 * finishes and this temporary bump can't break anything. If @kn
1108 * is alive, nothing changes. If @kn is being deactivated, the
1109 * soon-to-follow put will either finish deactivation or restore
1110 * deactivated state. If @kn is already removed, the temporary
1111 * bump is guaranteed to be gone before @kn is released.
1112 */
1113 atomic_inc(&kn->active);
1114 if (kernfs_lockdep(kn))
1115 rwsem_acquire(&kn->dep_map, 0, 1, _RET_IP_);
1116}
1117
1118/**
1119 * kernfs_remove_self - remove a kernfs_node from its own method
1120 * @kn: the self kernfs_node to remove
1121 *
1122 * The caller must be running off of a kernfs operation which is invoked
1123 * with an active reference - e.g. one of kernfs_ops. This can be used to
1124 * implement a file operation which deletes itself.
1125 *
1126 * For example, the "delete" file for a sysfs device directory can be
1127 * implemented by invoking kernfs_remove_self() on the "delete" file
1128 * itself. This function breaks the circular dependency of trying to
1129 * deactivate self while holding an active ref itself. It isn't necessary
1130 * to modify the usual removal path to use kernfs_remove_self(). The
1131 * "delete" implementation can simply invoke kernfs_remove_self() on self
1132 * before proceeding with the usual removal path. kernfs will ignore later
1133 * kernfs_remove() on self.
1134 *
1135 * kernfs_remove_self() can be called multiple times concurrently on the
1136 * same kernfs_node. Only the first one actually performs removal and
1137 * returns %true. All others will wait until the kernfs operation which
1138 * won self-removal finishes and return %false. Note that the losers wait
1139 * for the completion of not only the winning kernfs_remove_self() but also
1140 * the whole kernfs_ops which won the arbitration. This can be used to
1141 * guarantee, for example, all concurrent writes to a "delete" file to
1142 * finish only after the whole operation is complete.
1143 */
1144bool kernfs_remove_self(struct kernfs_node *kn)
1145{
1146 bool ret;
1147
1148 mutex_lock(&kernfs_mutex);
1149 kernfs_break_active_protection(kn);
1150
1151 /*
1152 * SUICIDAL is used to arbitrate among competing invocations. Only
1153 * the first one will actually perform removal. When the removal
1154 * is complete, SUICIDED is set and the active ref is restored
1155 * while holding kernfs_mutex. The ones which lost arbitration
1156 * waits for SUICDED && drained which can happen only after the
1157 * enclosing kernfs operation which executed the winning instance
1158 * of kernfs_remove_self() finished.
1159 */
1160 if (!(kn->flags & KERNFS_SUICIDAL)) {
1161 kn->flags |= KERNFS_SUICIDAL;
1162 __kernfs_remove(kn);
1163 kn->flags |= KERNFS_SUICIDED;
1164 ret = true;
1165 } else {
1166 wait_queue_head_t *waitq = &kernfs_root(kn)->deactivate_waitq;
1167 DEFINE_WAIT(wait);
1168
1169 while (true) {
1170 prepare_to_wait(waitq, &wait, TASK_UNINTERRUPTIBLE);
1171
1172 if ((kn->flags & KERNFS_SUICIDED) &&
1173 atomic_read(&kn->active) == KN_DEACTIVATED_BIAS)
1174 break;
1175
1176 mutex_unlock(&kernfs_mutex);
1177 schedule();
1178 mutex_lock(&kernfs_mutex);
1179 }
1180 finish_wait(waitq, &wait);
1181 WARN_ON_ONCE(!RB_EMPTY_NODE(&kn->rb));
1182 ret = false;
1183 }
1184
1185 /*
1186 * This must be done while holding kernfs_mutex; otherwise, waiting
1187 * for SUICIDED && deactivated could finish prematurely.
1188 */
1189 kernfs_unbreak_active_protection(kn);
1190
1191 mutex_unlock(&kernfs_mutex);
1192 return ret;
1193}
1194
1195/**
Tejun Heo324a56e2013-12-11 14:11:53 -05001196 * kernfs_remove_by_name_ns - find a kernfs_node by name and remove it
1197 * @parent: parent of the target
1198 * @name: name of the kernfs_node to remove
1199 * @ns: namespace tag of the kernfs_node to remove
Tejun Heofd7b9f72013-11-28 14:54:33 -05001200 *
Tejun Heo324a56e2013-12-11 14:11:53 -05001201 * Look for the kernfs_node with @name and @ns under @parent and remove it.
1202 * Returns 0 on success, -ENOENT if such entry doesn't exist.
Tejun Heofd7b9f72013-11-28 14:54:33 -05001203 */
Tejun Heo324a56e2013-12-11 14:11:53 -05001204int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name,
Tejun Heofd7b9f72013-11-28 14:54:33 -05001205 const void *ns)
1206{
Tejun Heo324a56e2013-12-11 14:11:53 -05001207 struct kernfs_node *kn;
Tejun Heofd7b9f72013-11-28 14:54:33 -05001208
Tejun Heo324a56e2013-12-11 14:11:53 -05001209 if (!parent) {
Tejun Heoc637b8a2013-12-11 14:11:58 -05001210 WARN(1, KERN_WARNING "kernfs: can not remove '%s', no directory\n",
Tejun Heofd7b9f72013-11-28 14:54:33 -05001211 name);
1212 return -ENOENT;
1213 }
1214
Tejun Heo988cd7a2014-02-03 14:02:58 -05001215 mutex_lock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001216
Tejun Heo324a56e2013-12-11 14:11:53 -05001217 kn = kernfs_find_ns(parent, name, ns);
1218 if (kn)
Tejun Heo988cd7a2014-02-03 14:02:58 -05001219 __kernfs_remove(kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001220
Tejun Heo988cd7a2014-02-03 14:02:58 -05001221 mutex_unlock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001222
Tejun Heo324a56e2013-12-11 14:11:53 -05001223 if (kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -05001224 return 0;
1225 else
1226 return -ENOENT;
1227}
1228
1229/**
1230 * kernfs_rename_ns - move and rename a kernfs_node
Tejun Heo324a56e2013-12-11 14:11:53 -05001231 * @kn: target node
Tejun Heofd7b9f72013-11-28 14:54:33 -05001232 * @new_parent: new parent to put @sd under
1233 * @new_name: new name
1234 * @new_ns: new namespace tag
1235 */
Tejun Heo324a56e2013-12-11 14:11:53 -05001236int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent,
Tejun Heofd7b9f72013-11-28 14:54:33 -05001237 const char *new_name, const void *new_ns)
1238{
Tejun Heo3eef34a2014-02-07 13:32:07 -05001239 struct kernfs_node *old_parent;
1240 const char *old_name = NULL;
Tejun Heofd7b9f72013-11-28 14:54:33 -05001241 int error;
1242
Tejun Heo3eef34a2014-02-07 13:32:07 -05001243 /* can't move or rename root */
1244 if (!kn->parent)
1245 return -EINVAL;
1246
Tejun Heoae343722014-01-10 08:57:21 -05001247 mutex_lock(&kernfs_mutex);
Tejun Heod0ae3d42013-12-11 16:02:56 -05001248
Greg Kroah-Hartman798c75a2014-01-13 14:36:03 -08001249 error = -ENOENT;
Tejun Heo81c173c2014-02-03 14:03:00 -05001250 if (!kernfs_active(kn) || !kernfs_active(new_parent))
Greg Kroah-Hartman798c75a2014-01-13 14:36:03 -08001251 goto out;
1252
Tejun Heofd7b9f72013-11-28 14:54:33 -05001253 error = 0;
Tejun Heoadc5e8b2013-12-11 14:11:54 -05001254 if ((kn->parent == new_parent) && (kn->ns == new_ns) &&
1255 (strcmp(kn->name, new_name) == 0))
Greg Kroah-Hartman798c75a2014-01-13 14:36:03 -08001256 goto out; /* nothing to rename */
Tejun Heofd7b9f72013-11-28 14:54:33 -05001257
1258 error = -EEXIST;
1259 if (kernfs_find_ns(new_parent, new_name, new_ns))
Greg Kroah-Hartman798c75a2014-01-13 14:36:03 -08001260 goto out;
Tejun Heofd7b9f72013-11-28 14:54:33 -05001261
Tejun Heo324a56e2013-12-11 14:11:53 -05001262 /* rename kernfs_node */
Tejun Heoadc5e8b2013-12-11 14:11:54 -05001263 if (strcmp(kn->name, new_name) != 0) {
Tejun Heofd7b9f72013-11-28 14:54:33 -05001264 error = -ENOMEM;
Andrzej Hajda75287a62015-02-13 14:36:27 -08001265 new_name = kstrdup_const(new_name, GFP_KERNEL);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001266 if (!new_name)
Greg Kroah-Hartman798c75a2014-01-13 14:36:03 -08001267 goto out;
Tejun Heo3eef34a2014-02-07 13:32:07 -05001268 } else {
1269 new_name = NULL;
Tejun Heofd7b9f72013-11-28 14:54:33 -05001270 }
1271
1272 /*
1273 * Move to the appropriate place in the appropriate directories rbtree.
1274 */
Tejun Heoc637b8a2013-12-11 14:11:58 -05001275 kernfs_unlink_sibling(kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001276 kernfs_get(new_parent);
Tejun Heo3eef34a2014-02-07 13:32:07 -05001277
1278 /* rename_lock protects ->parent and ->name accessors */
1279 spin_lock_irq(&kernfs_rename_lock);
1280
1281 old_parent = kn->parent;
Tejun Heoadc5e8b2013-12-11 14:11:54 -05001282 kn->parent = new_parent;
Tejun Heo3eef34a2014-02-07 13:32:07 -05001283
1284 kn->ns = new_ns;
1285 if (new_name) {
Tejun Heodfeb07502015-02-13 14:36:31 -08001286 old_name = kn->name;
Tejun Heo3eef34a2014-02-07 13:32:07 -05001287 kn->name = new_name;
1288 }
1289
1290 spin_unlock_irq(&kernfs_rename_lock);
1291
Tejun Heo9561a892014-02-10 17:57:09 -05001292 kn->hash = kernfs_name_hash(kn->name, kn->ns);
Tejun Heoc637b8a2013-12-11 14:11:58 -05001293 kernfs_link_sibling(kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001294
Tejun Heo3eef34a2014-02-07 13:32:07 -05001295 kernfs_put(old_parent);
Andrzej Hajda75287a62015-02-13 14:36:27 -08001296 kfree_const(old_name);
Tejun Heo3eef34a2014-02-07 13:32:07 -05001297
Tejun Heofd7b9f72013-11-28 14:54:33 -05001298 error = 0;
Greg Kroah-Hartman798c75a2014-01-13 14:36:03 -08001299 out:
Tejun Heoa797bfc2013-12-11 14:11:57 -05001300 mutex_unlock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001301 return error;
1302}
1303
Tejun Heofd7b9f72013-11-28 14:54:33 -05001304/* Relationship between s_mode and the DT_xxx types */
Tejun Heo324a56e2013-12-11 14:11:53 -05001305static inline unsigned char dt_type(struct kernfs_node *kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -05001306{
Tejun Heoadc5e8b2013-12-11 14:11:54 -05001307 return (kn->mode >> 12) & 15;
Tejun Heofd7b9f72013-11-28 14:54:33 -05001308}
1309
Tejun Heoc637b8a2013-12-11 14:11:58 -05001310static int kernfs_dir_fop_release(struct inode *inode, struct file *filp)
Tejun Heofd7b9f72013-11-28 14:54:33 -05001311{
1312 kernfs_put(filp->private_data);
1313 return 0;
1314}
1315
Tejun Heoc637b8a2013-12-11 14:11:58 -05001316static struct kernfs_node *kernfs_dir_pos(const void *ns,
Tejun Heo324a56e2013-12-11 14:11:53 -05001317 struct kernfs_node *parent, loff_t hash, struct kernfs_node *pos)
Tejun Heofd7b9f72013-11-28 14:54:33 -05001318{
1319 if (pos) {
Tejun Heo81c173c2014-02-03 14:03:00 -05001320 int valid = kernfs_active(pos) &&
Greg Kroah-Hartman798c75a2014-01-13 14:36:03 -08001321 pos->parent == parent && hash == pos->hash;
Tejun Heofd7b9f72013-11-28 14:54:33 -05001322 kernfs_put(pos);
1323 if (!valid)
1324 pos = NULL;
1325 }
1326 if (!pos && (hash > 1) && (hash < INT_MAX)) {
Tejun Heoadc5e8b2013-12-11 14:11:54 -05001327 struct rb_node *node = parent->dir.children.rb_node;
Tejun Heofd7b9f72013-11-28 14:54:33 -05001328 while (node) {
Tejun Heo324a56e2013-12-11 14:11:53 -05001329 pos = rb_to_kn(node);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001330
Tejun Heoadc5e8b2013-12-11 14:11:54 -05001331 if (hash < pos->hash)
Tejun Heofd7b9f72013-11-28 14:54:33 -05001332 node = node->rb_left;
Tejun Heoadc5e8b2013-12-11 14:11:54 -05001333 else if (hash > pos->hash)
Tejun Heofd7b9f72013-11-28 14:54:33 -05001334 node = node->rb_right;
1335 else
1336 break;
1337 }
1338 }
Tejun Heob9c9dad2014-02-03 14:09:11 -05001339 /* Skip over entries which are dying/dead or in the wrong namespace */
1340 while (pos && (!kernfs_active(pos) || pos->ns != ns)) {
Tejun Heoadc5e8b2013-12-11 14:11:54 -05001341 struct rb_node *node = rb_next(&pos->rb);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001342 if (!node)
1343 pos = NULL;
1344 else
Tejun Heo324a56e2013-12-11 14:11:53 -05001345 pos = rb_to_kn(node);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001346 }
1347 return pos;
1348}
1349
Tejun Heoc637b8a2013-12-11 14:11:58 -05001350static struct kernfs_node *kernfs_dir_next_pos(const void *ns,
Tejun Heo324a56e2013-12-11 14:11:53 -05001351 struct kernfs_node *parent, ino_t ino, struct kernfs_node *pos)
Tejun Heofd7b9f72013-11-28 14:54:33 -05001352{
Tejun Heoc637b8a2013-12-11 14:11:58 -05001353 pos = kernfs_dir_pos(ns, parent, ino, pos);
Tejun Heob9c9dad2014-02-03 14:09:11 -05001354 if (pos) {
Tejun Heofd7b9f72013-11-28 14:54:33 -05001355 do {
Tejun Heoadc5e8b2013-12-11 14:11:54 -05001356 struct rb_node *node = rb_next(&pos->rb);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001357 if (!node)
1358 pos = NULL;
1359 else
Tejun Heo324a56e2013-12-11 14:11:53 -05001360 pos = rb_to_kn(node);
Tejun Heob9c9dad2014-02-03 14:09:11 -05001361 } while (pos && (!kernfs_active(pos) || pos->ns != ns));
1362 }
Tejun Heofd7b9f72013-11-28 14:54:33 -05001363 return pos;
1364}
1365
Tejun Heoc637b8a2013-12-11 14:11:58 -05001366static int kernfs_fop_readdir(struct file *file, struct dir_context *ctx)
Tejun Heofd7b9f72013-11-28 14:54:33 -05001367{
1368 struct dentry *dentry = file->f_path.dentry;
Tejun Heo324a56e2013-12-11 14:11:53 -05001369 struct kernfs_node *parent = dentry->d_fsdata;
1370 struct kernfs_node *pos = file->private_data;
Tejun Heofd7b9f72013-11-28 14:54:33 -05001371 const void *ns = NULL;
1372
1373 if (!dir_emit_dots(file, ctx))
1374 return 0;
Tejun Heoa797bfc2013-12-11 14:11:57 -05001375 mutex_lock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001376
Tejun Heo324a56e2013-12-11 14:11:53 -05001377 if (kernfs_ns_enabled(parent))
Tejun Heoc525aad2013-12-11 14:11:55 -05001378 ns = kernfs_info(dentry->d_sb)->ns;
Tejun Heofd7b9f72013-11-28 14:54:33 -05001379
Tejun Heoc637b8a2013-12-11 14:11:58 -05001380 for (pos = kernfs_dir_pos(ns, parent, ctx->pos, pos);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001381 pos;
Tejun Heoc637b8a2013-12-11 14:11:58 -05001382 pos = kernfs_dir_next_pos(ns, parent, ctx->pos, pos)) {
Tejun Heoadc5e8b2013-12-11 14:11:54 -05001383 const char *name = pos->name;
Tejun Heofd7b9f72013-11-28 14:54:33 -05001384 unsigned int type = dt_type(pos);
1385 int len = strlen(name);
Tejun Heoadc5e8b2013-12-11 14:11:54 -05001386 ino_t ino = pos->ino;
Tejun Heofd7b9f72013-11-28 14:54:33 -05001387
Tejun Heoadc5e8b2013-12-11 14:11:54 -05001388 ctx->pos = pos->hash;
Tejun Heofd7b9f72013-11-28 14:54:33 -05001389 file->private_data = pos;
1390 kernfs_get(pos);
1391
Tejun Heoa797bfc2013-12-11 14:11:57 -05001392 mutex_unlock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001393 if (!dir_emit(ctx, name, len, ino, type))
1394 return 0;
Tejun Heoa797bfc2013-12-11 14:11:57 -05001395 mutex_lock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001396 }
Tejun Heoa797bfc2013-12-11 14:11:57 -05001397 mutex_unlock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001398 file->private_data = NULL;
1399 ctx->pos = INT_MAX;
1400 return 0;
1401}
1402
Tejun Heoc637b8a2013-12-11 14:11:58 -05001403static loff_t kernfs_dir_fop_llseek(struct file *file, loff_t offset,
1404 int whence)
Tejun Heofd7b9f72013-11-28 14:54:33 -05001405{
1406 struct inode *inode = file_inode(file);
1407 loff_t ret;
1408
1409 mutex_lock(&inode->i_mutex);
1410 ret = generic_file_llseek(file, offset, whence);
1411 mutex_unlock(&inode->i_mutex);
1412
1413 return ret;
1414}
1415
Tejun Heoa797bfc2013-12-11 14:11:57 -05001416const struct file_operations kernfs_dir_fops = {
Tejun Heofd7b9f72013-11-28 14:54:33 -05001417 .read = generic_read_dir,
Tejun Heoc637b8a2013-12-11 14:11:58 -05001418 .iterate = kernfs_fop_readdir,
1419 .release = kernfs_dir_fop_release,
1420 .llseek = kernfs_dir_fop_llseek,
Tejun Heofd7b9f72013-11-28 14:54:33 -05001421};