blob: 03b688d19f6964010c27c16759520315892c780d [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
Aditya Kali9f6df572016-01-29 02:54:04 -060047/* kernfs_node_depth - compute depth from @from to @to */
48static size_t kernfs_depth(struct kernfs_node *from, struct kernfs_node *to)
Tejun Heo3eef34a2014-02-07 13:32:07 -050049{
Aditya Kali9f6df572016-01-29 02:54:04 -060050 size_t depth = 0;
Tejun Heo3eef34a2014-02-07 13:32:07 -050051
Aditya Kali9f6df572016-01-29 02:54:04 -060052 while (to->parent && to != from) {
53 depth++;
54 to = to->parent;
55 }
56 return depth;
57}
Tejun Heo3eef34a2014-02-07 13:32:07 -050058
Aditya Kali9f6df572016-01-29 02:54:04 -060059static struct kernfs_node *kernfs_common_ancestor(struct kernfs_node *a,
60 struct kernfs_node *b)
61{
62 size_t da, db;
63 struct kernfs_root *ra = kernfs_root(a), *rb = kernfs_root(b);
Tejun Heo3eef34a2014-02-07 13:32:07 -050064
Aditya Kali9f6df572016-01-29 02:54:04 -060065 if (ra != rb)
66 return NULL;
67
68 da = kernfs_depth(ra->kn, a);
69 db = kernfs_depth(rb->kn, b);
70
71 while (da > db) {
72 a = a->parent;
73 da--;
74 }
75 while (db > da) {
76 b = b->parent;
77 db--;
78 }
79
80 /* worst case b and a will be the same at root */
81 while (b != a) {
82 b = b->parent;
83 a = a->parent;
84 }
85
86 return a;
87}
88
89/**
90 * kernfs_path_from_node_locked - find a pseudo-absolute path to @kn_to,
91 * where kn_from is treated as root of the path.
92 * @kn_from: kernfs node which should be treated as root for the path
93 * @kn_to: kernfs node to which path is needed
94 * @buf: buffer to copy the path into
95 * @buflen: size of @buf
96 *
97 * We need to handle couple of scenarios here:
98 * [1] when @kn_from is an ancestor of @kn_to at some level
99 * kn_from: /n1/n2/n3
100 * kn_to: /n1/n2/n3/n4/n5
101 * result: /n4/n5
102 *
103 * [2] when @kn_from is on a different hierarchy and we need to find common
104 * ancestor between @kn_from and @kn_to.
105 * kn_from: /n1/n2/n3/n4
106 * kn_to: /n1/n2/n5
107 * result: /../../n5
108 * OR
109 * kn_from: /n1/n2/n3/n4/n5 [depth=5]
110 * kn_to: /n1/n2/n3 [depth=3]
111 * result: /../..
112 *
113 * return value: length of the string. If greater than buflen,
114 * then contents of buf are undefined. On error, -1 is returned.
115 */
116static int kernfs_path_from_node_locked(struct kernfs_node *kn_to,
117 struct kernfs_node *kn_from,
118 char *buf, size_t buflen)
119{
120 struct kernfs_node *kn, *common;
121 const char parent_str[] = "/..";
122 size_t depth_from, depth_to, len = 0, nlen = 0;
123 char *p;
124 int i;
125
126 if (!kn_from)
127 kn_from = kernfs_root(kn_to)->kn;
128
129 if (kn_from == kn_to)
130 return strlcpy(buf, "/", buflen);
131
132 common = kernfs_common_ancestor(kn_from, kn_to);
133 if (WARN_ON(!common))
134 return -1;
135
136 depth_to = kernfs_depth(common, kn_to);
137 depth_from = kernfs_depth(common, kn_from);
138
139 if (buf)
140 buf[0] = '\0';
141
142 for (i = 0; i < depth_from; i++)
143 len += strlcpy(buf + len, parent_str,
144 len < buflen ? buflen - len : 0);
145
146 /* Calculate how many bytes we need for the rest */
147 for (kn = kn_to; kn != common; kn = kn->parent)
148 nlen += strlen(kn->name) + 1;
149
150 if (len + nlen >= buflen)
151 return len + nlen;
152
153 p = buf + len + nlen;
154 *p = '\0';
155 for (kn = kn_to; kn != common; kn = kn->parent) {
156 nlen = strlen(kn->name);
157 p -= nlen;
158 memcpy(p, kn->name, nlen);
159 *(--p) = '/';
160 }
161
162 return len + nlen;
Tejun Heo3eef34a2014-02-07 13:32:07 -0500163}
164
165/**
166 * kernfs_name - obtain the name of a given node
167 * @kn: kernfs_node of interest
168 * @buf: buffer to copy @kn's name into
169 * @buflen: size of @buf
170 *
171 * Copies the name of @kn into @buf of @buflen bytes. The behavior is
172 * similar to strlcpy(). It returns the length of @kn's name and if @buf
173 * isn't long enough, it's filled upto @buflen-1 and nul terminated.
174 *
175 * This function can be called from any context.
176 */
177int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen)
178{
179 unsigned long flags;
180 int ret;
181
182 spin_lock_irqsave(&kernfs_rename_lock, flags);
183 ret = kernfs_name_locked(kn, buf, buflen);
184 spin_unlock_irqrestore(&kernfs_rename_lock, flags);
185 return ret;
186}
187
188/**
Tejun Heo9acee9c2015-08-18 14:54:55 -0700189 * kernfs_path_len - determine the length of the full path of a given node
190 * @kn: kernfs_node of interest
191 *
192 * The returned length doesn't include the space for the terminating '\0'.
193 */
194size_t kernfs_path_len(struct kernfs_node *kn)
195{
196 size_t len = 0;
197 unsigned long flags;
198
199 spin_lock_irqsave(&kernfs_rename_lock, flags);
200
201 do {
202 len += strlen(kn->name) + 1;
203 kn = kn->parent;
204 } while (kn && kn->parent);
205
206 spin_unlock_irqrestore(&kernfs_rename_lock, flags);
207
208 return len;
209}
210
211/**
Aditya Kali9f6df572016-01-29 02:54:04 -0600212 * kernfs_path_from_node - build path of node @to relative to @from.
213 * @from: parent kernfs_node relative to which we need to build the path
214 * @to: kernfs_node of interest
215 * @buf: buffer to copy @to's path into
216 * @buflen: size of @buf
217 *
218 * Builds @to's path relative to @from in @buf. @from and @to must
219 * be on the same kernfs-root. If @from is not parent of @to, then a relative
220 * path (which includes '..'s) as needed to reach from @from to @to is
221 * returned.
222 *
223 * If @buf isn't long enough, the return value will be greater than @buflen
224 * and @buf contents are undefined.
225 */
226int kernfs_path_from_node(struct kernfs_node *to, struct kernfs_node *from,
227 char *buf, size_t buflen)
228{
229 unsigned long flags;
230 int ret;
231
232 spin_lock_irqsave(&kernfs_rename_lock, flags);
233 ret = kernfs_path_from_node_locked(to, from, buf, buflen);
234 spin_unlock_irqrestore(&kernfs_rename_lock, flags);
235 return ret;
236}
237EXPORT_SYMBOL_GPL(kernfs_path_from_node);
238
239/**
Tejun Heo3eef34a2014-02-07 13:32:07 -0500240 * kernfs_path - build full path of a given node
241 * @kn: kernfs_node of interest
242 * @buf: buffer to copy @kn's name into
243 * @buflen: size of @buf
244 *
245 * Builds and returns the full path of @kn in @buf of @buflen bytes. The
246 * path is built from the end of @buf so the returned pointer usually
247 * doesn't match @buf. If @buf isn't long enough, @buf is nul terminated
248 * and %NULL is returned.
249 */
250char *kernfs_path(struct kernfs_node *kn, char *buf, size_t buflen)
251{
Aditya Kali9f6df572016-01-29 02:54:04 -0600252 int ret;
Tejun Heo3eef34a2014-02-07 13:32:07 -0500253
Aditya Kali9f6df572016-01-29 02:54:04 -0600254 ret = kernfs_path_from_node(kn, NULL, buf, buflen);
255 if (ret < 0 || ret >= buflen)
256 return NULL;
257 return buf;
Tejun Heo3eef34a2014-02-07 13:32:07 -0500258}
Tejun Heoe61734c2014-02-12 09:29:50 -0500259EXPORT_SYMBOL_GPL(kernfs_path);
Tejun Heo3eef34a2014-02-07 13:32:07 -0500260
261/**
262 * pr_cont_kernfs_name - pr_cont name of a kernfs_node
263 * @kn: kernfs_node of interest
264 *
265 * This function can be called from any context.
266 */
267void pr_cont_kernfs_name(struct kernfs_node *kn)
268{
269 unsigned long flags;
270
271 spin_lock_irqsave(&kernfs_rename_lock, flags);
272
273 kernfs_name_locked(kn, kernfs_pr_cont_buf, sizeof(kernfs_pr_cont_buf));
274 pr_cont("%s", kernfs_pr_cont_buf);
275
276 spin_unlock_irqrestore(&kernfs_rename_lock, flags);
277}
278
279/**
280 * pr_cont_kernfs_path - pr_cont path of a kernfs_node
281 * @kn: kernfs_node of interest
282 *
283 * This function can be called from any context.
284 */
285void pr_cont_kernfs_path(struct kernfs_node *kn)
286{
287 unsigned long flags;
Aditya Kali9f6df572016-01-29 02:54:04 -0600288 int sz;
Tejun Heo3eef34a2014-02-07 13:32:07 -0500289
290 spin_lock_irqsave(&kernfs_rename_lock, flags);
291
Aditya Kali9f6df572016-01-29 02:54:04 -0600292 sz = kernfs_path_from_node_locked(kn, NULL, kernfs_pr_cont_buf,
293 sizeof(kernfs_pr_cont_buf));
294 if (sz < 0) {
295 pr_cont("(error)");
296 goto out;
297 }
Tejun Heo3eef34a2014-02-07 13:32:07 -0500298
Aditya Kali9f6df572016-01-29 02:54:04 -0600299 if (sz >= sizeof(kernfs_pr_cont_buf)) {
300 pr_cont("(name too long)");
301 goto out;
302 }
303
304 pr_cont("%s", kernfs_pr_cont_buf);
305
306out:
Tejun Heo3eef34a2014-02-07 13:32:07 -0500307 spin_unlock_irqrestore(&kernfs_rename_lock, flags);
308}
309
310/**
311 * kernfs_get_parent - determine the parent node and pin it
312 * @kn: kernfs_node of interest
313 *
314 * Determines @kn's parent, pins and returns it. This function can be
315 * called from any context.
316 */
317struct kernfs_node *kernfs_get_parent(struct kernfs_node *kn)
318{
319 struct kernfs_node *parent;
320 unsigned long flags;
321
322 spin_lock_irqsave(&kernfs_rename_lock, flags);
323 parent = kn->parent;
324 kernfs_get(parent);
325 spin_unlock_irqrestore(&kernfs_rename_lock, flags);
326
327 return parent;
328}
329
Tejun Heofd7b9f72013-11-28 14:54:33 -0500330/**
Tejun Heoc637b8a2013-12-11 14:11:58 -0500331 * kernfs_name_hash
Tejun Heofd7b9f72013-11-28 14:54:33 -0500332 * @name: Null terminated string to hash
333 * @ns: Namespace tag to hash
334 *
335 * Returns 31 bit hash of ns + name (so it fits in an off_t )
336 */
Tejun Heoc637b8a2013-12-11 14:11:58 -0500337static unsigned int kernfs_name_hash(const char *name, const void *ns)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500338{
339 unsigned long hash = init_name_hash();
340 unsigned int len = strlen(name);
341 while (len--)
342 hash = partial_name_hash(*name++, hash);
343 hash = (end_name_hash(hash) ^ hash_ptr((void *)ns, 31));
344 hash &= 0x7fffffffU;
345 /* Reserve hash numbers 0, 1 and INT_MAX for magic directory entries */
Richard Cochran88391d42014-03-05 17:10:52 +0100346 if (hash < 2)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500347 hash += 2;
348 if (hash >= INT_MAX)
349 hash = INT_MAX - 1;
350 return hash;
351}
352
Tejun Heoc637b8a2013-12-11 14:11:58 -0500353static int kernfs_name_compare(unsigned int hash, const char *name,
354 const void *ns, const struct kernfs_node *kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500355{
Rasmus Villemoes72392ed2014-12-05 23:41:33 +0100356 if (hash < kn->hash)
357 return -1;
358 if (hash > kn->hash)
359 return 1;
360 if (ns < kn->ns)
361 return -1;
362 if (ns > kn->ns)
363 return 1;
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500364 return strcmp(name, kn->name);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500365}
366
Tejun Heoc637b8a2013-12-11 14:11:58 -0500367static int kernfs_sd_compare(const struct kernfs_node *left,
368 const struct kernfs_node *right)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500369{
Tejun Heoc637b8a2013-12-11 14:11:58 -0500370 return kernfs_name_compare(left->hash, left->name, left->ns, right);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500371}
372
373/**
Tejun Heoc637b8a2013-12-11 14:11:58 -0500374 * kernfs_link_sibling - link kernfs_node into sibling rbtree
Tejun Heo324a56e2013-12-11 14:11:53 -0500375 * @kn: kernfs_node of interest
Tejun Heofd7b9f72013-11-28 14:54:33 -0500376 *
Tejun Heo324a56e2013-12-11 14:11:53 -0500377 * Link @kn into its sibling rbtree which starts from
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500378 * @kn->parent->dir.children.
Tejun Heofd7b9f72013-11-28 14:54:33 -0500379 *
380 * Locking:
Tejun Heoa797bfc2013-12-11 14:11:57 -0500381 * mutex_lock(kernfs_mutex)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500382 *
383 * RETURNS:
384 * 0 on susccess -EEXIST on failure.
385 */
Tejun Heoc637b8a2013-12-11 14:11:58 -0500386static int kernfs_link_sibling(struct kernfs_node *kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500387{
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500388 struct rb_node **node = &kn->parent->dir.children.rb_node;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500389 struct rb_node *parent = NULL;
390
Tejun Heofd7b9f72013-11-28 14:54:33 -0500391 while (*node) {
Tejun Heo324a56e2013-12-11 14:11:53 -0500392 struct kernfs_node *pos;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500393 int result;
394
Tejun Heo324a56e2013-12-11 14:11:53 -0500395 pos = rb_to_kn(*node);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500396 parent = *node;
Tejun Heoc637b8a2013-12-11 14:11:58 -0500397 result = kernfs_sd_compare(kn, pos);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500398 if (result < 0)
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500399 node = &pos->rb.rb_left;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500400 else if (result > 0)
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500401 node = &pos->rb.rb_right;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500402 else
403 return -EEXIST;
404 }
Jianyu Zhanc1befb82014-04-17 17:52:10 +0800405
Tejun Heofd7b9f72013-11-28 14:54:33 -0500406 /* add new node and rebalance the tree */
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500407 rb_link_node(&kn->rb, parent, node);
408 rb_insert_color(&kn->rb, &kn->parent->dir.children);
Jianyu Zhanc1befb82014-04-17 17:52:10 +0800409
410 /* successfully added, account subdir number */
411 if (kernfs_type(kn) == KERNFS_DIR)
412 kn->parent->dir.subdirs++;
413
Tejun Heofd7b9f72013-11-28 14:54:33 -0500414 return 0;
415}
416
417/**
Tejun Heoc637b8a2013-12-11 14:11:58 -0500418 * kernfs_unlink_sibling - unlink kernfs_node from sibling rbtree
Tejun Heo324a56e2013-12-11 14:11:53 -0500419 * @kn: kernfs_node of interest
Tejun Heofd7b9f72013-11-28 14:54:33 -0500420 *
Tejun Heo35beab02014-02-03 14:02:56 -0500421 * Try to unlink @kn from its sibling rbtree which starts from
422 * kn->parent->dir.children. Returns %true if @kn was actually
423 * removed, %false if @kn wasn't on the rbtree.
Tejun Heofd7b9f72013-11-28 14:54:33 -0500424 *
425 * Locking:
Tejun Heoa797bfc2013-12-11 14:11:57 -0500426 * mutex_lock(kernfs_mutex)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500427 */
Tejun Heo35beab02014-02-03 14:02:56 -0500428static bool kernfs_unlink_sibling(struct kernfs_node *kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500429{
Tejun Heo35beab02014-02-03 14:02:56 -0500430 if (RB_EMPTY_NODE(&kn->rb))
431 return false;
432
Tejun Heodf23fc32013-12-11 14:11:56 -0500433 if (kernfs_type(kn) == KERNFS_DIR)
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500434 kn->parent->dir.subdirs--;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500435
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500436 rb_erase(&kn->rb, &kn->parent->dir.children);
Tejun Heo35beab02014-02-03 14:02:56 -0500437 RB_CLEAR_NODE(&kn->rb);
438 return true;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500439}
440
441/**
Tejun Heoc637b8a2013-12-11 14:11:58 -0500442 * kernfs_get_active - get an active reference to kernfs_node
Tejun Heo324a56e2013-12-11 14:11:53 -0500443 * @kn: kernfs_node to get an active reference to
Tejun Heofd7b9f72013-11-28 14:54:33 -0500444 *
Tejun Heo324a56e2013-12-11 14:11:53 -0500445 * Get an active reference of @kn. This function is noop if @kn
Tejun Heofd7b9f72013-11-28 14:54:33 -0500446 * is NULL.
447 *
448 * RETURNS:
Tejun Heo324a56e2013-12-11 14:11:53 -0500449 * Pointer to @kn on success, NULL on failure.
Tejun Heofd7b9f72013-11-28 14:54:33 -0500450 */
Tejun Heoc637b8a2013-12-11 14:11:58 -0500451struct kernfs_node *kernfs_get_active(struct kernfs_node *kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500452{
Tejun Heo324a56e2013-12-11 14:11:53 -0500453 if (unlikely(!kn))
Tejun Heofd7b9f72013-11-28 14:54:33 -0500454 return NULL;
455
Greg Kroah-Hartmanf4b3e632014-01-13 14:13:39 -0800456 if (!atomic_inc_unless_negative(&kn->active))
457 return NULL;
458
Tejun Heo182fd642014-02-03 14:02:59 -0500459 if (kernfs_lockdep(kn))
Tejun Heo324a56e2013-12-11 14:11:53 -0500460 rwsem_acquire_read(&kn->dep_map, 0, 1, _RET_IP_);
Greg Kroah-Hartmanf4b3e632014-01-13 14:13:39 -0800461 return kn;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500462}
463
464/**
Tejun Heoc637b8a2013-12-11 14:11:58 -0500465 * kernfs_put_active - put an active reference to kernfs_node
Tejun Heo324a56e2013-12-11 14:11:53 -0500466 * @kn: kernfs_node to put an active reference to
Tejun Heofd7b9f72013-11-28 14:54:33 -0500467 *
Tejun Heo324a56e2013-12-11 14:11:53 -0500468 * Put an active reference to @kn. This function is noop if @kn
Tejun Heofd7b9f72013-11-28 14:54:33 -0500469 * is NULL.
470 */
Tejun Heoc637b8a2013-12-11 14:11:58 -0500471void kernfs_put_active(struct kernfs_node *kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500472{
Tejun Heoabd54f02014-02-03 14:02:55 -0500473 struct kernfs_root *root = kernfs_root(kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500474 int v;
475
Tejun Heo324a56e2013-12-11 14:11:53 -0500476 if (unlikely(!kn))
Tejun Heofd7b9f72013-11-28 14:54:33 -0500477 return;
478
Tejun Heo182fd642014-02-03 14:02:59 -0500479 if (kernfs_lockdep(kn))
Tejun Heo324a56e2013-12-11 14:11:53 -0500480 rwsem_release(&kn->dep_map, 1, _RET_IP_);
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500481 v = atomic_dec_return(&kn->active);
Tejun Heodf23fc32013-12-11 14:11:56 -0500482 if (likely(v != KN_DEACTIVATED_BIAS))
Tejun Heofd7b9f72013-11-28 14:54:33 -0500483 return;
484
Tejun Heoabd54f02014-02-03 14:02:55 -0500485 wake_up_all(&root->deactivate_waitq);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500486}
487
488/**
Tejun Heo81c173c2014-02-03 14:03:00 -0500489 * kernfs_drain - drain kernfs_node
490 * @kn: kernfs_node to drain
Tejun Heofd7b9f72013-11-28 14:54:33 -0500491 *
Tejun Heo81c173c2014-02-03 14:03:00 -0500492 * Drain existing usages and nuke all existing mmaps of @kn. Mutiple
493 * removers may invoke this function concurrently on @kn and all will
494 * return after draining is complete.
Tejun Heofd7b9f72013-11-28 14:54:33 -0500495 */
Tejun Heo81c173c2014-02-03 14:03:00 -0500496static void kernfs_drain(struct kernfs_node *kn)
Tejun Heo35beab02014-02-03 14:02:56 -0500497 __releases(&kernfs_mutex) __acquires(&kernfs_mutex)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500498{
Tejun Heoabd54f02014-02-03 14:02:55 -0500499 struct kernfs_root *root = kernfs_root(kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500500
Tejun Heo35beab02014-02-03 14:02:56 -0500501 lockdep_assert_held(&kernfs_mutex);
Tejun Heo81c173c2014-02-03 14:03:00 -0500502 WARN_ON_ONCE(kernfs_active(kn));
Tejun Heo35beab02014-02-03 14:02:56 -0500503
504 mutex_unlock(&kernfs_mutex);
505
Tejun Heo182fd642014-02-03 14:02:59 -0500506 if (kernfs_lockdep(kn)) {
Tejun Heoa6607932014-02-03 14:02:54 -0500507 rwsem_acquire(&kn->dep_map, 0, 0, _RET_IP_);
Tejun Heo35beab02014-02-03 14:02:56 -0500508 if (atomic_read(&kn->active) != KN_DEACTIVATED_BIAS)
509 lock_contended(&kn->dep_map, _RET_IP_);
510 }
Greg Kroah-Hartman08901472014-01-13 14:39:52 -0800511
Tejun Heo35beab02014-02-03 14:02:56 -0500512 /* but everyone should wait for draining */
Tejun Heoabd54f02014-02-03 14:02:55 -0500513 wait_event(root->deactivate_waitq,
514 atomic_read(&kn->active) == KN_DEACTIVATED_BIAS);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500515
Tejun Heo182fd642014-02-03 14:02:59 -0500516 if (kernfs_lockdep(kn)) {
Tejun Heoa6607932014-02-03 14:02:54 -0500517 lock_acquired(&kn->dep_map, _RET_IP_);
518 rwsem_release(&kn->dep_map, 1, _RET_IP_);
519 }
Tejun Heo35beab02014-02-03 14:02:56 -0500520
Tejun Heoccf02aa2014-02-03 14:02:57 -0500521 kernfs_unmap_bin_file(kn);
522
Tejun Heo35beab02014-02-03 14:02:56 -0500523 mutex_lock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500524}
525
Tejun Heofd7b9f72013-11-28 14:54:33 -0500526/**
Tejun Heo324a56e2013-12-11 14:11:53 -0500527 * kernfs_get - get a reference count on a kernfs_node
528 * @kn: the target kernfs_node
Tejun Heofd7b9f72013-11-28 14:54:33 -0500529 */
Tejun Heo324a56e2013-12-11 14:11:53 -0500530void kernfs_get(struct kernfs_node *kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500531{
Tejun Heo324a56e2013-12-11 14:11:53 -0500532 if (kn) {
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500533 WARN_ON(!atomic_read(&kn->count));
534 atomic_inc(&kn->count);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500535 }
536}
537EXPORT_SYMBOL_GPL(kernfs_get);
538
539/**
Tejun Heo324a56e2013-12-11 14:11:53 -0500540 * kernfs_put - put a reference count on a kernfs_node
541 * @kn: the target kernfs_node
Tejun Heofd7b9f72013-11-28 14:54:33 -0500542 *
Tejun Heo324a56e2013-12-11 14:11:53 -0500543 * Put a reference count of @kn and destroy it if it reached zero.
Tejun Heofd7b9f72013-11-28 14:54:33 -0500544 */
Tejun Heo324a56e2013-12-11 14:11:53 -0500545void kernfs_put(struct kernfs_node *kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500546{
Tejun Heo324a56e2013-12-11 14:11:53 -0500547 struct kernfs_node *parent;
Tejun Heoba7443b2013-11-28 14:54:40 -0500548 struct kernfs_root *root;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500549
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500550 if (!kn || !atomic_dec_and_test(&kn->count))
Tejun Heofd7b9f72013-11-28 14:54:33 -0500551 return;
Tejun Heo324a56e2013-12-11 14:11:53 -0500552 root = kernfs_root(kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500553 repeat:
Tejun Heo81c173c2014-02-03 14:03:00 -0500554 /*
555 * Moving/renaming is always done while holding reference.
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500556 * kn->parent won't change beneath us.
Tejun Heofd7b9f72013-11-28 14:54:33 -0500557 */
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500558 parent = kn->parent;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500559
Tejun Heo81c173c2014-02-03 14:03:00 -0500560 WARN_ONCE(atomic_read(&kn->active) != KN_DEACTIVATED_BIAS,
561 "kernfs_put: %s/%s: released with incorrect active_ref %d\n",
562 parent ? parent->name : "", kn->name, atomic_read(&kn->active));
Tejun Heofd7b9f72013-11-28 14:54:33 -0500563
Tejun Heodf23fc32013-12-11 14:11:56 -0500564 if (kernfs_type(kn) == KERNFS_LINK)
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500565 kernfs_put(kn->symlink.target_kn);
Tejun Heodfeb07502015-02-13 14:36:31 -0800566
567 kfree_const(kn->name);
568
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500569 if (kn->iattr) {
570 if (kn->iattr->ia_secdata)
571 security_release_secctx(kn->iattr->ia_secdata,
572 kn->iattr->ia_secdata_len);
573 simple_xattrs_free(&kn->iattr->xattrs);
Tejun Heo23223922013-11-23 17:40:02 -0500574 }
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500575 kfree(kn->iattr);
576 ida_simple_remove(&root->ino_ida, kn->ino);
Tejun Heoa797bfc2013-12-11 14:11:57 -0500577 kmem_cache_free(kernfs_node_cache, kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500578
Tejun Heo324a56e2013-12-11 14:11:53 -0500579 kn = parent;
580 if (kn) {
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500581 if (atomic_dec_and_test(&kn->count))
Tejun Heoba7443b2013-11-28 14:54:40 -0500582 goto repeat;
583 } else {
Tejun Heo324a56e2013-12-11 14:11:53 -0500584 /* just released the root kn, free @root too */
Tejun Heobc755552013-11-28 14:54:41 -0500585 ida_destroy(&root->ino_ida);
Tejun Heoba7443b2013-11-28 14:54:40 -0500586 kfree(root);
587 }
Tejun Heofd7b9f72013-11-28 14:54:33 -0500588}
589EXPORT_SYMBOL_GPL(kernfs_put);
590
Tejun Heoc637b8a2013-12-11 14:11:58 -0500591static int kernfs_dop_revalidate(struct dentry *dentry, unsigned int flags)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500592{
Tejun Heo324a56e2013-12-11 14:11:53 -0500593 struct kernfs_node *kn;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500594
595 if (flags & LOOKUP_RCU)
596 return -ECHILD;
597
Tejun Heo19bbb922013-12-11 16:02:59 -0500598 /* Always perform fresh lookup for negatives */
David Howells2b0143b2015-03-17 22:25:59 +0000599 if (d_really_is_negative(dentry))
Tejun Heo19bbb922013-12-11 16:02:59 -0500600 goto out_bad_unlocked;
601
Tejun Heo324a56e2013-12-11 14:11:53 -0500602 kn = dentry->d_fsdata;
Tejun Heoa797bfc2013-12-11 14:11:57 -0500603 mutex_lock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500604
Tejun Heo81c173c2014-02-03 14:03:00 -0500605 /* The kernfs node has been deactivated */
606 if (!kernfs_active(kn))
Tejun Heofd7b9f72013-11-28 14:54:33 -0500607 goto out_bad;
608
Tejun Heoc637b8a2013-12-11 14:11:58 -0500609 /* The kernfs node has been moved? */
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500610 if (dentry->d_parent->d_fsdata != kn->parent)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500611 goto out_bad;
612
Tejun Heoc637b8a2013-12-11 14:11:58 -0500613 /* The kernfs node has been renamed */
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500614 if (strcmp(dentry->d_name.name, kn->name) != 0)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500615 goto out_bad;
616
Tejun Heoc637b8a2013-12-11 14:11:58 -0500617 /* The kernfs node has been moved to a different namespace */
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500618 if (kn->parent && kernfs_ns_enabled(kn->parent) &&
Tejun Heoc525aad2013-12-11 14:11:55 -0500619 kernfs_info(dentry->d_sb)->ns != kn->ns)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500620 goto out_bad;
621
Tejun Heoa797bfc2013-12-11 14:11:57 -0500622 mutex_unlock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500623 return 1;
624out_bad:
Tejun Heoa797bfc2013-12-11 14:11:57 -0500625 mutex_unlock(&kernfs_mutex);
Tejun Heo19bbb922013-12-11 16:02:59 -0500626out_bad_unlocked:
Tejun Heofd7b9f72013-11-28 14:54:33 -0500627 return 0;
628}
629
Tejun Heoc637b8a2013-12-11 14:11:58 -0500630static void kernfs_dop_release(struct dentry *dentry)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500631{
632 kernfs_put(dentry->d_fsdata);
633}
634
Tejun Heoa797bfc2013-12-11 14:11:57 -0500635const struct dentry_operations kernfs_dops = {
Tejun Heoc637b8a2013-12-11 14:11:58 -0500636 .d_revalidate = kernfs_dop_revalidate,
Tejun Heoc637b8a2013-12-11 14:11:58 -0500637 .d_release = kernfs_dop_release,
Tejun Heofd7b9f72013-11-28 14:54:33 -0500638};
639
Tejun Heo0c23b222014-02-03 14:09:15 -0500640/**
641 * kernfs_node_from_dentry - determine kernfs_node associated with a dentry
642 * @dentry: the dentry in question
643 *
644 * Return the kernfs_node associated with @dentry. If @dentry is not a
645 * kernfs one, %NULL is returned.
646 *
647 * While the returned kernfs_node will stay accessible as long as @dentry
648 * is accessible, the returned node can be in any state and the caller is
649 * fully responsible for determining what's accessible.
650 */
651struct kernfs_node *kernfs_node_from_dentry(struct dentry *dentry)
652{
Li Zefanf41c5932014-02-14 16:57:27 +0800653 if (dentry->d_sb->s_op == &kernfs_sops)
Tejun Heo0c23b222014-02-03 14:09:15 -0500654 return dentry->d_fsdata;
655 return NULL;
656}
657
Tejun Heodb4aad22014-01-17 09:58:25 -0500658static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root,
659 const char *name, umode_t mode,
660 unsigned flags)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500661{
Tejun Heo324a56e2013-12-11 14:11:53 -0500662 struct kernfs_node *kn;
Tejun Heobc755552013-11-28 14:54:41 -0500663 int ret;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500664
Tejun Heodfeb07502015-02-13 14:36:31 -0800665 name = kstrdup_const(name, GFP_KERNEL);
666 if (!name)
667 return NULL;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500668
Tejun Heoa797bfc2013-12-11 14:11:57 -0500669 kn = kmem_cache_zalloc(kernfs_node_cache, GFP_KERNEL);
Tejun Heo324a56e2013-12-11 14:11:53 -0500670 if (!kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500671 goto err_out1;
672
Vladimir Davydovb2a209f2016-01-14 15:18:05 -0800673 ret = ida_simple_get(&root->ino_ida, 1, 0, GFP_KERNEL);
Tejun Heobc755552013-11-28 14:54:41 -0500674 if (ret < 0)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500675 goto err_out2;
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500676 kn->ino = ret;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500677
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500678 atomic_set(&kn->count, 1);
Tejun Heo81c173c2014-02-03 14:03:00 -0500679 atomic_set(&kn->active, KN_DEACTIVATED_BIAS);
Tejun Heo35beab02014-02-03 14:02:56 -0500680 RB_CLEAR_NODE(&kn->rb);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500681
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500682 kn->name = name;
683 kn->mode = mode;
Tejun Heo81c173c2014-02-03 14:03:00 -0500684 kn->flags = flags;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500685
Tejun Heo324a56e2013-12-11 14:11:53 -0500686 return kn;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500687
688 err_out2:
Tejun Heoa797bfc2013-12-11 14:11:57 -0500689 kmem_cache_free(kernfs_node_cache, kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500690 err_out1:
Tejun Heodfeb07502015-02-13 14:36:31 -0800691 kfree_const(name);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500692 return NULL;
693}
694
Tejun Heodb4aad22014-01-17 09:58:25 -0500695struct kernfs_node *kernfs_new_node(struct kernfs_node *parent,
696 const char *name, umode_t mode,
697 unsigned flags)
698{
699 struct kernfs_node *kn;
700
701 kn = __kernfs_new_node(kernfs_root(parent), name, mode, flags);
702 if (kn) {
703 kernfs_get(parent);
704 kn->parent = parent;
705 }
706 return kn;
707}
708
Tejun Heofd7b9f72013-11-28 14:54:33 -0500709/**
Tejun Heoc637b8a2013-12-11 14:11:58 -0500710 * kernfs_add_one - add kernfs_node to parent without warning
Tejun Heo324a56e2013-12-11 14:11:53 -0500711 * @kn: kernfs_node to be added
Tejun Heofd7b9f72013-11-28 14:54:33 -0500712 *
Tejun Heodb4aad22014-01-17 09:58:25 -0500713 * The caller must already have initialized @kn->parent. This
714 * function increments nlink of the parent's inode if @kn is a
715 * directory and link into the children list of the parent.
Tejun Heofd7b9f72013-11-28 14:54:33 -0500716 *
Tejun Heofd7b9f72013-11-28 14:54:33 -0500717 * RETURNS:
718 * 0 on success, -EEXIST if entry with the given name already
719 * exists.
720 */
Tejun Heo988cd7a2014-02-03 14:02:58 -0500721int kernfs_add_one(struct kernfs_node *kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500722{
Tejun Heodb4aad22014-01-17 09:58:25 -0500723 struct kernfs_node *parent = kn->parent;
Tejun Heoc525aad2013-12-11 14:11:55 -0500724 struct kernfs_iattrs *ps_iattr;
Tejun Heo988cd7a2014-02-03 14:02:58 -0500725 bool has_ns;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500726 int ret;
727
Tejun Heo988cd7a2014-02-03 14:02:58 -0500728 mutex_lock(&kernfs_mutex);
729
730 ret = -EINVAL;
731 has_ns = kernfs_ns_enabled(parent);
732 if (WARN(has_ns != (bool)kn->ns, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n",
733 has_ns ? "required" : "invalid", parent->name, kn->name))
734 goto out_unlock;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500735
Tejun Heodf23fc32013-12-11 14:11:56 -0500736 if (kernfs_type(parent) != KERNFS_DIR)
Tejun Heo988cd7a2014-02-03 14:02:58 -0500737 goto out_unlock;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500738
Tejun Heo988cd7a2014-02-03 14:02:58 -0500739 ret = -ENOENT;
Eric W. Biedermanea015212015-05-13 16:09:29 -0500740 if (parent->flags & KERNFS_EMPTY_DIR)
741 goto out_unlock;
742
Tejun Heod35258e2014-02-03 14:09:12 -0500743 if ((parent->flags & KERNFS_ACTIVATED) && !kernfs_active(parent))
Tejun Heo988cd7a2014-02-03 14:02:58 -0500744 goto out_unlock;
Greg Kroah-Hartman798c75a2014-01-13 14:36:03 -0800745
Tejun Heoc637b8a2013-12-11 14:11:58 -0500746 kn->hash = kernfs_name_hash(kn->name, kn->ns);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500747
Tejun Heoc637b8a2013-12-11 14:11:58 -0500748 ret = kernfs_link_sibling(kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500749 if (ret)
Tejun Heo988cd7a2014-02-03 14:02:58 -0500750 goto out_unlock;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500751
752 /* Update timestamps on the parent */
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500753 ps_iattr = parent->iattr;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500754 if (ps_iattr) {
755 struct iattr *ps_iattrs = &ps_iattr->ia_iattr;
756 ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME;
757 }
758
Tejun Heod35258e2014-02-03 14:09:12 -0500759 mutex_unlock(&kernfs_mutex);
760
761 /*
762 * Activate the new node unless CREATE_DEACTIVATED is requested.
763 * If not activated here, the kernfs user is responsible for
764 * activating the node with kernfs_activate(). A node which hasn't
765 * been activated is not visible to userland and its removal won't
766 * trigger deactivation.
767 */
768 if (!(kernfs_root(kn)->flags & KERNFS_ROOT_CREATE_DEACTIVATED))
769 kernfs_activate(kn);
770 return 0;
771
Tejun Heo988cd7a2014-02-03 14:02:58 -0500772out_unlock:
Tejun Heoa797bfc2013-12-11 14:11:57 -0500773 mutex_unlock(&kernfs_mutex);
Tejun Heo988cd7a2014-02-03 14:02:58 -0500774 return ret;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500775}
776
777/**
Tejun Heo324a56e2013-12-11 14:11:53 -0500778 * kernfs_find_ns - find kernfs_node with the given name
779 * @parent: kernfs_node to search under
Tejun Heofd7b9f72013-11-28 14:54:33 -0500780 * @name: name to look for
781 * @ns: the namespace tag to use
782 *
Tejun Heo324a56e2013-12-11 14:11:53 -0500783 * Look for kernfs_node with name @name under @parent. Returns pointer to
784 * the found kernfs_node on success, %NULL on failure.
Tejun Heofd7b9f72013-11-28 14:54:33 -0500785 */
Tejun Heo324a56e2013-12-11 14:11:53 -0500786static struct kernfs_node *kernfs_find_ns(struct kernfs_node *parent,
787 const unsigned char *name,
788 const void *ns)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500789{
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500790 struct rb_node *node = parent->dir.children.rb_node;
Tejun Heoac9bba02013-11-29 17:19:09 -0500791 bool has_ns = kernfs_ns_enabled(parent);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500792 unsigned int hash;
793
Tejun Heoa797bfc2013-12-11 14:11:57 -0500794 lockdep_assert_held(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500795
796 if (has_ns != (bool)ns) {
Tejun Heoc637b8a2013-12-11 14:11:58 -0500797 WARN(1, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n",
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500798 has_ns ? "required" : "invalid", parent->name, name);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500799 return NULL;
800 }
801
Tejun Heoc637b8a2013-12-11 14:11:58 -0500802 hash = kernfs_name_hash(name, ns);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500803 while (node) {
Tejun Heo324a56e2013-12-11 14:11:53 -0500804 struct kernfs_node *kn;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500805 int result;
806
Tejun Heo324a56e2013-12-11 14:11:53 -0500807 kn = rb_to_kn(node);
Tejun Heoc637b8a2013-12-11 14:11:58 -0500808 result = kernfs_name_compare(hash, name, ns, kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500809 if (result < 0)
810 node = node->rb_left;
811 else if (result > 0)
812 node = node->rb_right;
813 else
Tejun Heo324a56e2013-12-11 14:11:53 -0500814 return kn;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500815 }
816 return NULL;
817}
818
Tejun Heobd96f762015-11-20 15:55:52 -0500819static struct kernfs_node *kernfs_walk_ns(struct kernfs_node *parent,
820 const unsigned char *path,
821 const void *ns)
822{
Tejun Heoe56ed3582016-01-15 12:30:14 -0500823 size_t len;
824 char *p, *name;
Tejun Heobd96f762015-11-20 15:55:52 -0500825
826 lockdep_assert_held(&kernfs_mutex);
827
Tejun Heoe56ed3582016-01-15 12:30:14 -0500828 /* grab kernfs_rename_lock to piggy back on kernfs_pr_cont_buf */
829 spin_lock_irq(&kernfs_rename_lock);
830
831 len = strlcpy(kernfs_pr_cont_buf, path, sizeof(kernfs_pr_cont_buf));
832
833 if (len >= sizeof(kernfs_pr_cont_buf)) {
834 spin_unlock_irq(&kernfs_rename_lock);
Tejun Heobd96f762015-11-20 15:55:52 -0500835 return NULL;
Tejun Heoe56ed3582016-01-15 12:30:14 -0500836 }
837
838 p = kernfs_pr_cont_buf;
Tejun Heobd96f762015-11-20 15:55:52 -0500839
840 while ((name = strsep(&p, "/")) && parent) {
841 if (*name == '\0')
842 continue;
843 parent = kernfs_find_ns(parent, name, ns);
844 }
845
Tejun Heoe56ed3582016-01-15 12:30:14 -0500846 spin_unlock_irq(&kernfs_rename_lock);
847
Tejun Heobd96f762015-11-20 15:55:52 -0500848 return parent;
849}
850
Tejun Heofd7b9f72013-11-28 14:54:33 -0500851/**
Tejun Heo324a56e2013-12-11 14:11:53 -0500852 * kernfs_find_and_get_ns - find and get kernfs_node with the given name
853 * @parent: kernfs_node to search under
Tejun Heofd7b9f72013-11-28 14:54:33 -0500854 * @name: name to look for
855 * @ns: the namespace tag to use
856 *
Tejun Heo324a56e2013-12-11 14:11:53 -0500857 * Look for kernfs_node with name @name under @parent and get a reference
Tejun Heofd7b9f72013-11-28 14:54:33 -0500858 * if found. This function may sleep and returns pointer to the found
Tejun Heo324a56e2013-12-11 14:11:53 -0500859 * kernfs_node on success, %NULL on failure.
Tejun Heofd7b9f72013-11-28 14:54:33 -0500860 */
Tejun Heo324a56e2013-12-11 14:11:53 -0500861struct kernfs_node *kernfs_find_and_get_ns(struct kernfs_node *parent,
862 const char *name, const void *ns)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500863{
Tejun Heo324a56e2013-12-11 14:11:53 -0500864 struct kernfs_node *kn;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500865
Tejun Heoa797bfc2013-12-11 14:11:57 -0500866 mutex_lock(&kernfs_mutex);
Tejun Heo324a56e2013-12-11 14:11:53 -0500867 kn = kernfs_find_ns(parent, name, ns);
868 kernfs_get(kn);
Tejun Heoa797bfc2013-12-11 14:11:57 -0500869 mutex_unlock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500870
Tejun Heo324a56e2013-12-11 14:11:53 -0500871 return kn;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500872}
873EXPORT_SYMBOL_GPL(kernfs_find_and_get_ns);
874
875/**
Tejun Heobd96f762015-11-20 15:55:52 -0500876 * kernfs_walk_and_get_ns - find and get kernfs_node with the given path
877 * @parent: kernfs_node to search under
878 * @path: path to look for
879 * @ns: the namespace tag to use
880 *
881 * Look for kernfs_node with path @path under @parent and get a reference
882 * if found. This function may sleep and returns pointer to the found
883 * kernfs_node on success, %NULL on failure.
884 */
885struct kernfs_node *kernfs_walk_and_get_ns(struct kernfs_node *parent,
886 const char *path, const void *ns)
887{
888 struct kernfs_node *kn;
889
890 mutex_lock(&kernfs_mutex);
891 kn = kernfs_walk_ns(parent, path, ns);
892 kernfs_get(kn);
893 mutex_unlock(&kernfs_mutex);
894
895 return kn;
896}
897
898/**
Tejun Heoba7443b2013-11-28 14:54:40 -0500899 * kernfs_create_root - create a new kernfs hierarchy
Tejun Heo90c07c82014-02-03 14:09:09 -0500900 * @scops: optional syscall operations for the hierarchy
Tejun Heod35258e2014-02-03 14:09:12 -0500901 * @flags: KERNFS_ROOT_* flags
Tejun Heoba7443b2013-11-28 14:54:40 -0500902 * @priv: opaque data associated with the new directory
903 *
904 * Returns the root of the new hierarchy on success, ERR_PTR() value on
905 * failure.
906 */
Tejun Heo90c07c82014-02-03 14:09:09 -0500907struct kernfs_root *kernfs_create_root(struct kernfs_syscall_ops *scops,
Tejun Heod35258e2014-02-03 14:09:12 -0500908 unsigned int flags, void *priv)
Tejun Heoba7443b2013-11-28 14:54:40 -0500909{
910 struct kernfs_root *root;
Tejun Heo324a56e2013-12-11 14:11:53 -0500911 struct kernfs_node *kn;
Tejun Heoba7443b2013-11-28 14:54:40 -0500912
913 root = kzalloc(sizeof(*root), GFP_KERNEL);
914 if (!root)
915 return ERR_PTR(-ENOMEM);
916
Tejun Heobc755552013-11-28 14:54:41 -0500917 ida_init(&root->ino_ida);
Tejun Heo7d568a82014-04-09 11:07:30 -0400918 INIT_LIST_HEAD(&root->supers);
Tejun Heobc755552013-11-28 14:54:41 -0500919
Tejun Heodb4aad22014-01-17 09:58:25 -0500920 kn = __kernfs_new_node(root, "", S_IFDIR | S_IRUGO | S_IXUGO,
921 KERNFS_DIR);
Tejun Heo324a56e2013-12-11 14:11:53 -0500922 if (!kn) {
Tejun Heobc755552013-11-28 14:54:41 -0500923 ida_destroy(&root->ino_ida);
Tejun Heoba7443b2013-11-28 14:54:40 -0500924 kfree(root);
925 return ERR_PTR(-ENOMEM);
926 }
927
Tejun Heo324a56e2013-12-11 14:11:53 -0500928 kn->priv = priv;
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500929 kn->dir.root = root;
Tejun Heoba7443b2013-11-28 14:54:40 -0500930
Tejun Heo90c07c82014-02-03 14:09:09 -0500931 root->syscall_ops = scops;
Tejun Heod35258e2014-02-03 14:09:12 -0500932 root->flags = flags;
Tejun Heo324a56e2013-12-11 14:11:53 -0500933 root->kn = kn;
Tejun Heoabd54f02014-02-03 14:02:55 -0500934 init_waitqueue_head(&root->deactivate_waitq);
Tejun Heoba7443b2013-11-28 14:54:40 -0500935
Tejun Heod35258e2014-02-03 14:09:12 -0500936 if (!(root->flags & KERNFS_ROOT_CREATE_DEACTIVATED))
937 kernfs_activate(kn);
938
Tejun Heoba7443b2013-11-28 14:54:40 -0500939 return root;
940}
941
942/**
943 * kernfs_destroy_root - destroy a kernfs hierarchy
944 * @root: root of the hierarchy to destroy
945 *
946 * Destroy the hierarchy anchored at @root by removing all existing
947 * directories and destroying @root.
948 */
949void kernfs_destroy_root(struct kernfs_root *root)
950{
Tejun Heo324a56e2013-12-11 14:11:53 -0500951 kernfs_remove(root->kn); /* will also free @root */
Tejun Heoba7443b2013-11-28 14:54:40 -0500952}
953
954/**
Tejun Heofd7b9f72013-11-28 14:54:33 -0500955 * kernfs_create_dir_ns - create a directory
956 * @parent: parent in which to create a new directory
957 * @name: name of the new directory
Tejun Heobb8b9d092013-12-11 16:02:55 -0500958 * @mode: mode of the new directory
Tejun Heofd7b9f72013-11-28 14:54:33 -0500959 * @priv: opaque data associated with the new directory
960 * @ns: optional namespace tag of the directory
961 *
962 * Returns the created node on success, ERR_PTR() value on failure.
963 */
Tejun Heo324a56e2013-12-11 14:11:53 -0500964struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent,
Tejun Heobb8b9d092013-12-11 16:02:55 -0500965 const char *name, umode_t mode,
966 void *priv, const void *ns)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500967{
Tejun Heo324a56e2013-12-11 14:11:53 -0500968 struct kernfs_node *kn;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500969 int rc;
970
971 /* allocate */
Tejun Heodb4aad22014-01-17 09:58:25 -0500972 kn = kernfs_new_node(parent, name, mode | S_IFDIR, KERNFS_DIR);
Tejun Heo324a56e2013-12-11 14:11:53 -0500973 if (!kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -0500974 return ERR_PTR(-ENOMEM);
975
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500976 kn->dir.root = parent->dir.root;
977 kn->ns = ns;
Tejun Heo324a56e2013-12-11 14:11:53 -0500978 kn->priv = priv;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500979
980 /* link in */
Tejun Heo988cd7a2014-02-03 14:02:58 -0500981 rc = kernfs_add_one(kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500982 if (!rc)
Tejun Heo324a56e2013-12-11 14:11:53 -0500983 return kn;
Tejun Heofd7b9f72013-11-28 14:54:33 -0500984
Tejun Heo324a56e2013-12-11 14:11:53 -0500985 kernfs_put(kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -0500986 return ERR_PTR(rc);
987}
988
Eric W. Biedermanea015212015-05-13 16:09:29 -0500989/**
990 * kernfs_create_empty_dir - create an always empty directory
991 * @parent: parent in which to create a new directory
992 * @name: name of the new directory
993 *
994 * Returns the created node on success, ERR_PTR() value on failure.
995 */
996struct kernfs_node *kernfs_create_empty_dir(struct kernfs_node *parent,
997 const char *name)
998{
999 struct kernfs_node *kn;
1000 int rc;
1001
1002 /* allocate */
1003 kn = kernfs_new_node(parent, name, S_IRUGO|S_IXUGO|S_IFDIR, KERNFS_DIR);
1004 if (!kn)
1005 return ERR_PTR(-ENOMEM);
1006
1007 kn->flags |= KERNFS_EMPTY_DIR;
1008 kn->dir.root = parent->dir.root;
1009 kn->ns = NULL;
1010 kn->priv = NULL;
1011
1012 /* link in */
1013 rc = kernfs_add_one(kn);
1014 if (!rc)
1015 return kn;
1016
1017 kernfs_put(kn);
1018 return ERR_PTR(rc);
1019}
1020
Tejun Heoc637b8a2013-12-11 14:11:58 -05001021static struct dentry *kernfs_iop_lookup(struct inode *dir,
1022 struct dentry *dentry,
1023 unsigned int flags)
Tejun Heofd7b9f72013-11-28 14:54:33 -05001024{
Tejun Heo19bbb922013-12-11 16:02:59 -05001025 struct dentry *ret;
Tejun Heo324a56e2013-12-11 14:11:53 -05001026 struct kernfs_node *parent = dentry->d_parent->d_fsdata;
1027 struct kernfs_node *kn;
Tejun Heofd7b9f72013-11-28 14:54:33 -05001028 struct inode *inode;
1029 const void *ns = NULL;
1030
Tejun Heoa797bfc2013-12-11 14:11:57 -05001031 mutex_lock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001032
Tejun Heo324a56e2013-12-11 14:11:53 -05001033 if (kernfs_ns_enabled(parent))
Tejun Heoc525aad2013-12-11 14:11:55 -05001034 ns = kernfs_info(dir->i_sb)->ns;
Tejun Heofd7b9f72013-11-28 14:54:33 -05001035
Tejun Heo324a56e2013-12-11 14:11:53 -05001036 kn = kernfs_find_ns(parent, dentry->d_name.name, ns);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001037
1038 /* no such entry */
Tejun Heob9c9dad2014-02-03 14:09:11 -05001039 if (!kn || !kernfs_active(kn)) {
Tejun Heo19bbb922013-12-11 16:02:59 -05001040 ret = NULL;
Tejun Heofd7b9f72013-11-28 14:54:33 -05001041 goto out_unlock;
1042 }
Tejun Heo324a56e2013-12-11 14:11:53 -05001043 kernfs_get(kn);
1044 dentry->d_fsdata = kn;
Tejun Heofd7b9f72013-11-28 14:54:33 -05001045
1046 /* attach dentry and inode */
Tejun Heoc637b8a2013-12-11 14:11:58 -05001047 inode = kernfs_get_inode(dir->i_sb, kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001048 if (!inode) {
1049 ret = ERR_PTR(-ENOMEM);
1050 goto out_unlock;
1051 }
1052
1053 /* instantiate and hash dentry */
Al Viro41d28bc2014-10-12 22:24:21 -04001054 ret = d_splice_alias(inode, dentry);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001055 out_unlock:
Tejun Heoa797bfc2013-12-11 14:11:57 -05001056 mutex_unlock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001057 return ret;
1058}
1059
Tejun Heo80b9bbe2013-12-11 16:03:00 -05001060static int kernfs_iop_mkdir(struct inode *dir, struct dentry *dentry,
1061 umode_t mode)
1062{
1063 struct kernfs_node *parent = dir->i_private;
Tejun Heo90c07c82014-02-03 14:09:09 -05001064 struct kernfs_syscall_ops *scops = kernfs_root(parent)->syscall_ops;
Tejun Heo07c75302014-02-03 14:09:08 -05001065 int ret;
Tejun Heo80b9bbe2013-12-11 16:03:00 -05001066
Tejun Heo90c07c82014-02-03 14:09:09 -05001067 if (!scops || !scops->mkdir)
Tejun Heo80b9bbe2013-12-11 16:03:00 -05001068 return -EPERM;
1069
Tejun Heo07c75302014-02-03 14:09:08 -05001070 if (!kernfs_get_active(parent))
1071 return -ENODEV;
1072
Tejun Heo90c07c82014-02-03 14:09:09 -05001073 ret = scops->mkdir(parent, dentry->d_name.name, mode);
Tejun Heo07c75302014-02-03 14:09:08 -05001074
1075 kernfs_put_active(parent);
1076 return ret;
Tejun Heo80b9bbe2013-12-11 16:03:00 -05001077}
1078
1079static int kernfs_iop_rmdir(struct inode *dir, struct dentry *dentry)
1080{
1081 struct kernfs_node *kn = dentry->d_fsdata;
Tejun Heo90c07c82014-02-03 14:09:09 -05001082 struct kernfs_syscall_ops *scops = kernfs_root(kn)->syscall_ops;
Tejun Heo07c75302014-02-03 14:09:08 -05001083 int ret;
Tejun Heo80b9bbe2013-12-11 16:03:00 -05001084
Tejun Heo90c07c82014-02-03 14:09:09 -05001085 if (!scops || !scops->rmdir)
Tejun Heo80b9bbe2013-12-11 16:03:00 -05001086 return -EPERM;
1087
Tejun Heo07c75302014-02-03 14:09:08 -05001088 if (!kernfs_get_active(kn))
1089 return -ENODEV;
1090
Tejun Heo90c07c82014-02-03 14:09:09 -05001091 ret = scops->rmdir(kn);
Tejun Heo07c75302014-02-03 14:09:08 -05001092
1093 kernfs_put_active(kn);
1094 return ret;
Tejun Heo80b9bbe2013-12-11 16:03:00 -05001095}
1096
1097static int kernfs_iop_rename(struct inode *old_dir, struct dentry *old_dentry,
1098 struct inode *new_dir, struct dentry *new_dentry)
1099{
1100 struct kernfs_node *kn = old_dentry->d_fsdata;
1101 struct kernfs_node *new_parent = new_dir->i_private;
Tejun Heo90c07c82014-02-03 14:09:09 -05001102 struct kernfs_syscall_ops *scops = kernfs_root(kn)->syscall_ops;
Tejun Heo07c75302014-02-03 14:09:08 -05001103 int ret;
Tejun Heo80b9bbe2013-12-11 16:03:00 -05001104
Tejun Heo90c07c82014-02-03 14:09:09 -05001105 if (!scops || !scops->rename)
Tejun Heo80b9bbe2013-12-11 16:03:00 -05001106 return -EPERM;
1107
Tejun Heo07c75302014-02-03 14:09:08 -05001108 if (!kernfs_get_active(kn))
1109 return -ENODEV;
1110
1111 if (!kernfs_get_active(new_parent)) {
1112 kernfs_put_active(kn);
1113 return -ENODEV;
1114 }
1115
Tejun Heo90c07c82014-02-03 14:09:09 -05001116 ret = scops->rename(kn, new_parent, new_dentry->d_name.name);
Tejun Heo07c75302014-02-03 14:09:08 -05001117
1118 kernfs_put_active(new_parent);
1119 kernfs_put_active(kn);
1120 return ret;
Tejun Heo80b9bbe2013-12-11 16:03:00 -05001121}
1122
Tejun Heoa797bfc2013-12-11 14:11:57 -05001123const struct inode_operations kernfs_dir_iops = {
Tejun Heoc637b8a2013-12-11 14:11:58 -05001124 .lookup = kernfs_iop_lookup,
1125 .permission = kernfs_iop_permission,
1126 .setattr = kernfs_iop_setattr,
1127 .getattr = kernfs_iop_getattr,
1128 .setxattr = kernfs_iop_setxattr,
1129 .removexattr = kernfs_iop_removexattr,
1130 .getxattr = kernfs_iop_getxattr,
1131 .listxattr = kernfs_iop_listxattr,
Tejun Heo80b9bbe2013-12-11 16:03:00 -05001132
1133 .mkdir = kernfs_iop_mkdir,
1134 .rmdir = kernfs_iop_rmdir,
1135 .rename = kernfs_iop_rename,
Tejun Heofd7b9f72013-11-28 14:54:33 -05001136};
1137
Tejun Heoc637b8a2013-12-11 14:11:58 -05001138static struct kernfs_node *kernfs_leftmost_descendant(struct kernfs_node *pos)
Tejun Heofd7b9f72013-11-28 14:54:33 -05001139{
Tejun Heo324a56e2013-12-11 14:11:53 -05001140 struct kernfs_node *last;
Tejun Heofd7b9f72013-11-28 14:54:33 -05001141
1142 while (true) {
1143 struct rb_node *rbn;
1144
1145 last = pos;
1146
Tejun Heodf23fc32013-12-11 14:11:56 -05001147 if (kernfs_type(pos) != KERNFS_DIR)
Tejun Heofd7b9f72013-11-28 14:54:33 -05001148 break;
1149
Tejun Heoadc5e8b2013-12-11 14:11:54 -05001150 rbn = rb_first(&pos->dir.children);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001151 if (!rbn)
1152 break;
1153
Tejun Heo324a56e2013-12-11 14:11:53 -05001154 pos = rb_to_kn(rbn);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001155 }
1156
1157 return last;
1158}
1159
1160/**
Tejun Heoc637b8a2013-12-11 14:11:58 -05001161 * kernfs_next_descendant_post - find the next descendant for post-order walk
Tejun Heofd7b9f72013-11-28 14:54:33 -05001162 * @pos: the current position (%NULL to initiate traversal)
Tejun Heo324a56e2013-12-11 14:11:53 -05001163 * @root: kernfs_node whose descendants to walk
Tejun Heofd7b9f72013-11-28 14:54:33 -05001164 *
1165 * Find the next descendant to visit for post-order traversal of @root's
1166 * descendants. @root is included in the iteration and the last node to be
1167 * visited.
1168 */
Tejun Heoc637b8a2013-12-11 14:11:58 -05001169static struct kernfs_node *kernfs_next_descendant_post(struct kernfs_node *pos,
1170 struct kernfs_node *root)
Tejun Heofd7b9f72013-11-28 14:54:33 -05001171{
1172 struct rb_node *rbn;
1173
Tejun Heoa797bfc2013-12-11 14:11:57 -05001174 lockdep_assert_held(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001175
1176 /* if first iteration, visit leftmost descendant which may be root */
1177 if (!pos)
Tejun Heoc637b8a2013-12-11 14:11:58 -05001178 return kernfs_leftmost_descendant(root);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001179
1180 /* if we visited @root, we're done */
1181 if (pos == root)
1182 return NULL;
1183
1184 /* if there's an unvisited sibling, visit its leftmost descendant */
Tejun Heoadc5e8b2013-12-11 14:11:54 -05001185 rbn = rb_next(&pos->rb);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001186 if (rbn)
Tejun Heoc637b8a2013-12-11 14:11:58 -05001187 return kernfs_leftmost_descendant(rb_to_kn(rbn));
Tejun Heofd7b9f72013-11-28 14:54:33 -05001188
1189 /* no sibling left, visit parent */
Tejun Heoadc5e8b2013-12-11 14:11:54 -05001190 return pos->parent;
Tejun Heofd7b9f72013-11-28 14:54:33 -05001191}
1192
Tejun Heod35258e2014-02-03 14:09:12 -05001193/**
1194 * kernfs_activate - activate a node which started deactivated
1195 * @kn: kernfs_node whose subtree is to be activated
1196 *
1197 * If the root has KERNFS_ROOT_CREATE_DEACTIVATED set, a newly created node
1198 * needs to be explicitly activated. A node which hasn't been activated
1199 * isn't visible to userland and deactivation is skipped during its
1200 * removal. This is useful to construct atomic init sequences where
1201 * creation of multiple nodes should either succeed or fail atomically.
1202 *
1203 * The caller is responsible for ensuring that this function is not called
1204 * after kernfs_remove*() is invoked on @kn.
1205 */
1206void kernfs_activate(struct kernfs_node *kn)
1207{
1208 struct kernfs_node *pos;
1209
1210 mutex_lock(&kernfs_mutex);
1211
1212 pos = NULL;
1213 while ((pos = kernfs_next_descendant_post(pos, kn))) {
1214 if (!pos || (pos->flags & KERNFS_ACTIVATED))
1215 continue;
1216
1217 WARN_ON_ONCE(pos->parent && RB_EMPTY_NODE(&pos->rb));
1218 WARN_ON_ONCE(atomic_read(&pos->active) != KN_DEACTIVATED_BIAS);
1219
1220 atomic_sub(KN_DEACTIVATED_BIAS, &pos->active);
1221 pos->flags |= KERNFS_ACTIVATED;
1222 }
1223
1224 mutex_unlock(&kernfs_mutex);
1225}
1226
Tejun Heo988cd7a2014-02-03 14:02:58 -05001227static void __kernfs_remove(struct kernfs_node *kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -05001228{
Tejun Heo35beab02014-02-03 14:02:56 -05001229 struct kernfs_node *pos;
1230
1231 lockdep_assert_held(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001232
Tejun Heo6b0afc22014-02-03 14:03:01 -05001233 /*
1234 * Short-circuit if non-root @kn has already finished removal.
1235 * This is for kernfs_remove_self() which plays with active ref
1236 * after removal.
1237 */
1238 if (!kn || (kn->parent && RB_EMPTY_NODE(&kn->rb)))
Greg Kroah-Hartmance9b4992014-01-13 13:50:31 -08001239 return;
1240
Tejun Heoc637b8a2013-12-11 14:11:58 -05001241 pr_debug("kernfs %s: removing\n", kn->name);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001242
Tejun Heo81c173c2014-02-03 14:03:00 -05001243 /* prevent any new usage under @kn by deactivating all nodes */
Tejun Heo35beab02014-02-03 14:02:56 -05001244 pos = NULL;
1245 while ((pos = kernfs_next_descendant_post(pos, kn)))
Tejun Heo81c173c2014-02-03 14:03:00 -05001246 if (kernfs_active(pos))
1247 atomic_add(KN_DEACTIVATED_BIAS, &pos->active);
Tejun Heo35beab02014-02-03 14:02:56 -05001248
1249 /* deactivate and unlink the subtree node-by-node */
Tejun Heofd7b9f72013-11-28 14:54:33 -05001250 do {
Tejun Heo35beab02014-02-03 14:02:56 -05001251 pos = kernfs_leftmost_descendant(kn);
1252
1253 /*
Tejun Heo81c173c2014-02-03 14:03:00 -05001254 * kernfs_drain() drops kernfs_mutex temporarily and @pos's
1255 * base ref could have been put by someone else by the time
1256 * the function returns. Make sure it doesn't go away
1257 * underneath us.
Tejun Heo35beab02014-02-03 14:02:56 -05001258 */
1259 kernfs_get(pos);
1260
Tejun Heod35258e2014-02-03 14:09:12 -05001261 /*
1262 * Drain iff @kn was activated. This avoids draining and
1263 * its lockdep annotations for nodes which have never been
1264 * activated and allows embedding kernfs_remove() in create
1265 * error paths without worrying about draining.
1266 */
1267 if (kn->flags & KERNFS_ACTIVATED)
1268 kernfs_drain(pos);
1269 else
1270 WARN_ON_ONCE(atomic_read(&kn->active) != KN_DEACTIVATED_BIAS);
Tejun Heo35beab02014-02-03 14:02:56 -05001271
1272 /*
1273 * kernfs_unlink_sibling() succeeds once per node. Use it
1274 * to decide who's responsible for cleanups.
1275 */
1276 if (!pos->parent || kernfs_unlink_sibling(pos)) {
1277 struct kernfs_iattrs *ps_iattr =
1278 pos->parent ? pos->parent->iattr : NULL;
1279
1280 /* update timestamps on the parent */
1281 if (ps_iattr) {
1282 ps_iattr->ia_iattr.ia_ctime = CURRENT_TIME;
1283 ps_iattr->ia_iattr.ia_mtime = CURRENT_TIME;
1284 }
1285
Tejun Heo988cd7a2014-02-03 14:02:58 -05001286 kernfs_put(pos);
Tejun Heo35beab02014-02-03 14:02:56 -05001287 }
1288
1289 kernfs_put(pos);
1290 } while (pos != kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001291}
1292
1293/**
Tejun Heo324a56e2013-12-11 14:11:53 -05001294 * kernfs_remove - remove a kernfs_node recursively
1295 * @kn: the kernfs_node to remove
Tejun Heofd7b9f72013-11-28 14:54:33 -05001296 *
Tejun Heo324a56e2013-12-11 14:11:53 -05001297 * Remove @kn along with all its subdirectories and files.
Tejun Heofd7b9f72013-11-28 14:54:33 -05001298 */
Tejun Heo324a56e2013-12-11 14:11:53 -05001299void kernfs_remove(struct kernfs_node *kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -05001300{
Tejun Heo988cd7a2014-02-03 14:02:58 -05001301 mutex_lock(&kernfs_mutex);
1302 __kernfs_remove(kn);
1303 mutex_unlock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001304}
1305
1306/**
Tejun Heo6b0afc22014-02-03 14:03:01 -05001307 * kernfs_break_active_protection - break out of active protection
1308 * @kn: the self kernfs_node
1309 *
1310 * The caller must be running off of a kernfs operation which is invoked
1311 * with an active reference - e.g. one of kernfs_ops. Each invocation of
1312 * this function must also be matched with an invocation of
1313 * kernfs_unbreak_active_protection().
1314 *
1315 * This function releases the active reference of @kn the caller is
1316 * holding. Once this function is called, @kn may be removed at any point
1317 * and the caller is solely responsible for ensuring that the objects it
1318 * dereferences are accessible.
1319 */
1320void kernfs_break_active_protection(struct kernfs_node *kn)
1321{
1322 /*
1323 * Take out ourself out of the active ref dependency chain. If
1324 * we're called without an active ref, lockdep will complain.
1325 */
1326 kernfs_put_active(kn);
1327}
1328
1329/**
1330 * kernfs_unbreak_active_protection - undo kernfs_break_active_protection()
1331 * @kn: the self kernfs_node
1332 *
1333 * If kernfs_break_active_protection() was called, this function must be
1334 * invoked before finishing the kernfs operation. Note that while this
1335 * function restores the active reference, it doesn't and can't actually
1336 * restore the active protection - @kn may already or be in the process of
1337 * being removed. Once kernfs_break_active_protection() is invoked, that
1338 * protection is irreversibly gone for the kernfs operation instance.
1339 *
1340 * While this function may be called at any point after
1341 * kernfs_break_active_protection() is invoked, its most useful location
1342 * would be right before the enclosing kernfs operation returns.
1343 */
1344void kernfs_unbreak_active_protection(struct kernfs_node *kn)
1345{
1346 /*
1347 * @kn->active could be in any state; however, the increment we do
1348 * here will be undone as soon as the enclosing kernfs operation
1349 * finishes and this temporary bump can't break anything. If @kn
1350 * is alive, nothing changes. If @kn is being deactivated, the
1351 * soon-to-follow put will either finish deactivation or restore
1352 * deactivated state. If @kn is already removed, the temporary
1353 * bump is guaranteed to be gone before @kn is released.
1354 */
1355 atomic_inc(&kn->active);
1356 if (kernfs_lockdep(kn))
1357 rwsem_acquire(&kn->dep_map, 0, 1, _RET_IP_);
1358}
1359
1360/**
1361 * kernfs_remove_self - remove a kernfs_node from its own method
1362 * @kn: the self kernfs_node to remove
1363 *
1364 * The caller must be running off of a kernfs operation which is invoked
1365 * with an active reference - e.g. one of kernfs_ops. This can be used to
1366 * implement a file operation which deletes itself.
1367 *
1368 * For example, the "delete" file for a sysfs device directory can be
1369 * implemented by invoking kernfs_remove_self() on the "delete" file
1370 * itself. This function breaks the circular dependency of trying to
1371 * deactivate self while holding an active ref itself. It isn't necessary
1372 * to modify the usual removal path to use kernfs_remove_self(). The
1373 * "delete" implementation can simply invoke kernfs_remove_self() on self
1374 * before proceeding with the usual removal path. kernfs will ignore later
1375 * kernfs_remove() on self.
1376 *
1377 * kernfs_remove_self() can be called multiple times concurrently on the
1378 * same kernfs_node. Only the first one actually performs removal and
1379 * returns %true. All others will wait until the kernfs operation which
1380 * won self-removal finishes and return %false. Note that the losers wait
1381 * for the completion of not only the winning kernfs_remove_self() but also
1382 * the whole kernfs_ops which won the arbitration. This can be used to
1383 * guarantee, for example, all concurrent writes to a "delete" file to
1384 * finish only after the whole operation is complete.
1385 */
1386bool kernfs_remove_self(struct kernfs_node *kn)
1387{
1388 bool ret;
1389
1390 mutex_lock(&kernfs_mutex);
1391 kernfs_break_active_protection(kn);
1392
1393 /*
1394 * SUICIDAL is used to arbitrate among competing invocations. Only
1395 * the first one will actually perform removal. When the removal
1396 * is complete, SUICIDED is set and the active ref is restored
1397 * while holding kernfs_mutex. The ones which lost arbitration
1398 * waits for SUICDED && drained which can happen only after the
1399 * enclosing kernfs operation which executed the winning instance
1400 * of kernfs_remove_self() finished.
1401 */
1402 if (!(kn->flags & KERNFS_SUICIDAL)) {
1403 kn->flags |= KERNFS_SUICIDAL;
1404 __kernfs_remove(kn);
1405 kn->flags |= KERNFS_SUICIDED;
1406 ret = true;
1407 } else {
1408 wait_queue_head_t *waitq = &kernfs_root(kn)->deactivate_waitq;
1409 DEFINE_WAIT(wait);
1410
1411 while (true) {
1412 prepare_to_wait(waitq, &wait, TASK_UNINTERRUPTIBLE);
1413
1414 if ((kn->flags & KERNFS_SUICIDED) &&
1415 atomic_read(&kn->active) == KN_DEACTIVATED_BIAS)
1416 break;
1417
1418 mutex_unlock(&kernfs_mutex);
1419 schedule();
1420 mutex_lock(&kernfs_mutex);
1421 }
1422 finish_wait(waitq, &wait);
1423 WARN_ON_ONCE(!RB_EMPTY_NODE(&kn->rb));
1424 ret = false;
1425 }
1426
1427 /*
1428 * This must be done while holding kernfs_mutex; otherwise, waiting
1429 * for SUICIDED && deactivated could finish prematurely.
1430 */
1431 kernfs_unbreak_active_protection(kn);
1432
1433 mutex_unlock(&kernfs_mutex);
1434 return ret;
1435}
1436
1437/**
Tejun Heo324a56e2013-12-11 14:11:53 -05001438 * kernfs_remove_by_name_ns - find a kernfs_node by name and remove it
1439 * @parent: parent of the target
1440 * @name: name of the kernfs_node to remove
1441 * @ns: namespace tag of the kernfs_node to remove
Tejun Heofd7b9f72013-11-28 14:54:33 -05001442 *
Tejun Heo324a56e2013-12-11 14:11:53 -05001443 * Look for the kernfs_node with @name and @ns under @parent and remove it.
1444 * Returns 0 on success, -ENOENT if such entry doesn't exist.
Tejun Heofd7b9f72013-11-28 14:54:33 -05001445 */
Tejun Heo324a56e2013-12-11 14:11:53 -05001446int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name,
Tejun Heofd7b9f72013-11-28 14:54:33 -05001447 const void *ns)
1448{
Tejun Heo324a56e2013-12-11 14:11:53 -05001449 struct kernfs_node *kn;
Tejun Heofd7b9f72013-11-28 14:54:33 -05001450
Tejun Heo324a56e2013-12-11 14:11:53 -05001451 if (!parent) {
Tejun Heoc637b8a2013-12-11 14:11:58 -05001452 WARN(1, KERN_WARNING "kernfs: can not remove '%s', no directory\n",
Tejun Heofd7b9f72013-11-28 14:54:33 -05001453 name);
1454 return -ENOENT;
1455 }
1456
Tejun Heo988cd7a2014-02-03 14:02:58 -05001457 mutex_lock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001458
Tejun Heo324a56e2013-12-11 14:11:53 -05001459 kn = kernfs_find_ns(parent, name, ns);
1460 if (kn)
Tejun Heo988cd7a2014-02-03 14:02:58 -05001461 __kernfs_remove(kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001462
Tejun Heo988cd7a2014-02-03 14:02:58 -05001463 mutex_unlock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001464
Tejun Heo324a56e2013-12-11 14:11:53 -05001465 if (kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -05001466 return 0;
1467 else
1468 return -ENOENT;
1469}
1470
1471/**
1472 * kernfs_rename_ns - move and rename a kernfs_node
Tejun Heo324a56e2013-12-11 14:11:53 -05001473 * @kn: target node
Tejun Heofd7b9f72013-11-28 14:54:33 -05001474 * @new_parent: new parent to put @sd under
1475 * @new_name: new name
1476 * @new_ns: new namespace tag
1477 */
Tejun Heo324a56e2013-12-11 14:11:53 -05001478int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent,
Tejun Heofd7b9f72013-11-28 14:54:33 -05001479 const char *new_name, const void *new_ns)
1480{
Tejun Heo3eef34a2014-02-07 13:32:07 -05001481 struct kernfs_node *old_parent;
1482 const char *old_name = NULL;
Tejun Heofd7b9f72013-11-28 14:54:33 -05001483 int error;
1484
Tejun Heo3eef34a2014-02-07 13:32:07 -05001485 /* can't move or rename root */
1486 if (!kn->parent)
1487 return -EINVAL;
1488
Tejun Heoae343722014-01-10 08:57:21 -05001489 mutex_lock(&kernfs_mutex);
Tejun Heod0ae3d42013-12-11 16:02:56 -05001490
Greg Kroah-Hartman798c75a2014-01-13 14:36:03 -08001491 error = -ENOENT;
Eric W. Biedermanea015212015-05-13 16:09:29 -05001492 if (!kernfs_active(kn) || !kernfs_active(new_parent) ||
1493 (new_parent->flags & KERNFS_EMPTY_DIR))
Greg Kroah-Hartman798c75a2014-01-13 14:36:03 -08001494 goto out;
1495
Tejun Heofd7b9f72013-11-28 14:54:33 -05001496 error = 0;
Tejun Heoadc5e8b2013-12-11 14:11:54 -05001497 if ((kn->parent == new_parent) && (kn->ns == new_ns) &&
1498 (strcmp(kn->name, new_name) == 0))
Greg Kroah-Hartman798c75a2014-01-13 14:36:03 -08001499 goto out; /* nothing to rename */
Tejun Heofd7b9f72013-11-28 14:54:33 -05001500
1501 error = -EEXIST;
1502 if (kernfs_find_ns(new_parent, new_name, new_ns))
Greg Kroah-Hartman798c75a2014-01-13 14:36:03 -08001503 goto out;
Tejun Heofd7b9f72013-11-28 14:54:33 -05001504
Tejun Heo324a56e2013-12-11 14:11:53 -05001505 /* rename kernfs_node */
Tejun Heoadc5e8b2013-12-11 14:11:54 -05001506 if (strcmp(kn->name, new_name) != 0) {
Tejun Heofd7b9f72013-11-28 14:54:33 -05001507 error = -ENOMEM;
Andrzej Hajda75287a62015-02-13 14:36:27 -08001508 new_name = kstrdup_const(new_name, GFP_KERNEL);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001509 if (!new_name)
Greg Kroah-Hartman798c75a2014-01-13 14:36:03 -08001510 goto out;
Tejun Heo3eef34a2014-02-07 13:32:07 -05001511 } else {
1512 new_name = NULL;
Tejun Heofd7b9f72013-11-28 14:54:33 -05001513 }
1514
1515 /*
1516 * Move to the appropriate place in the appropriate directories rbtree.
1517 */
Tejun Heoc637b8a2013-12-11 14:11:58 -05001518 kernfs_unlink_sibling(kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001519 kernfs_get(new_parent);
Tejun Heo3eef34a2014-02-07 13:32:07 -05001520
1521 /* rename_lock protects ->parent and ->name accessors */
1522 spin_lock_irq(&kernfs_rename_lock);
1523
1524 old_parent = kn->parent;
Tejun Heoadc5e8b2013-12-11 14:11:54 -05001525 kn->parent = new_parent;
Tejun Heo3eef34a2014-02-07 13:32:07 -05001526
1527 kn->ns = new_ns;
1528 if (new_name) {
Tejun Heodfeb07502015-02-13 14:36:31 -08001529 old_name = kn->name;
Tejun Heo3eef34a2014-02-07 13:32:07 -05001530 kn->name = new_name;
1531 }
1532
1533 spin_unlock_irq(&kernfs_rename_lock);
1534
Tejun Heo9561a892014-02-10 17:57:09 -05001535 kn->hash = kernfs_name_hash(kn->name, kn->ns);
Tejun Heoc637b8a2013-12-11 14:11:58 -05001536 kernfs_link_sibling(kn);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001537
Tejun Heo3eef34a2014-02-07 13:32:07 -05001538 kernfs_put(old_parent);
Andrzej Hajda75287a62015-02-13 14:36:27 -08001539 kfree_const(old_name);
Tejun Heo3eef34a2014-02-07 13:32:07 -05001540
Tejun Heofd7b9f72013-11-28 14:54:33 -05001541 error = 0;
Greg Kroah-Hartman798c75a2014-01-13 14:36:03 -08001542 out:
Tejun Heoa797bfc2013-12-11 14:11:57 -05001543 mutex_unlock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001544 return error;
1545}
1546
Tejun Heofd7b9f72013-11-28 14:54:33 -05001547/* Relationship between s_mode and the DT_xxx types */
Tejun Heo324a56e2013-12-11 14:11:53 -05001548static inline unsigned char dt_type(struct kernfs_node *kn)
Tejun Heofd7b9f72013-11-28 14:54:33 -05001549{
Tejun Heoadc5e8b2013-12-11 14:11:54 -05001550 return (kn->mode >> 12) & 15;
Tejun Heofd7b9f72013-11-28 14:54:33 -05001551}
1552
Tejun Heoc637b8a2013-12-11 14:11:58 -05001553static int kernfs_dir_fop_release(struct inode *inode, struct file *filp)
Tejun Heofd7b9f72013-11-28 14:54:33 -05001554{
1555 kernfs_put(filp->private_data);
1556 return 0;
1557}
1558
Tejun Heoc637b8a2013-12-11 14:11:58 -05001559static struct kernfs_node *kernfs_dir_pos(const void *ns,
Tejun Heo324a56e2013-12-11 14:11:53 -05001560 struct kernfs_node *parent, loff_t hash, struct kernfs_node *pos)
Tejun Heofd7b9f72013-11-28 14:54:33 -05001561{
1562 if (pos) {
Tejun Heo81c173c2014-02-03 14:03:00 -05001563 int valid = kernfs_active(pos) &&
Greg Kroah-Hartman798c75a2014-01-13 14:36:03 -08001564 pos->parent == parent && hash == pos->hash;
Tejun Heofd7b9f72013-11-28 14:54:33 -05001565 kernfs_put(pos);
1566 if (!valid)
1567 pos = NULL;
1568 }
1569 if (!pos && (hash > 1) && (hash < INT_MAX)) {
Tejun Heoadc5e8b2013-12-11 14:11:54 -05001570 struct rb_node *node = parent->dir.children.rb_node;
Tejun Heofd7b9f72013-11-28 14:54:33 -05001571 while (node) {
Tejun Heo324a56e2013-12-11 14:11:53 -05001572 pos = rb_to_kn(node);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001573
Tejun Heoadc5e8b2013-12-11 14:11:54 -05001574 if (hash < pos->hash)
Tejun Heofd7b9f72013-11-28 14:54:33 -05001575 node = node->rb_left;
Tejun Heoadc5e8b2013-12-11 14:11:54 -05001576 else if (hash > pos->hash)
Tejun Heofd7b9f72013-11-28 14:54:33 -05001577 node = node->rb_right;
1578 else
1579 break;
1580 }
1581 }
Tejun Heob9c9dad2014-02-03 14:09:11 -05001582 /* Skip over entries which are dying/dead or in the wrong namespace */
1583 while (pos && (!kernfs_active(pos) || pos->ns != ns)) {
Tejun Heoadc5e8b2013-12-11 14:11:54 -05001584 struct rb_node *node = rb_next(&pos->rb);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001585 if (!node)
1586 pos = NULL;
1587 else
Tejun Heo324a56e2013-12-11 14:11:53 -05001588 pos = rb_to_kn(node);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001589 }
1590 return pos;
1591}
1592
Tejun Heoc637b8a2013-12-11 14:11:58 -05001593static struct kernfs_node *kernfs_dir_next_pos(const void *ns,
Tejun Heo324a56e2013-12-11 14:11:53 -05001594 struct kernfs_node *parent, ino_t ino, struct kernfs_node *pos)
Tejun Heofd7b9f72013-11-28 14:54:33 -05001595{
Tejun Heoc637b8a2013-12-11 14:11:58 -05001596 pos = kernfs_dir_pos(ns, parent, ino, pos);
Tejun Heob9c9dad2014-02-03 14:09:11 -05001597 if (pos) {
Tejun Heofd7b9f72013-11-28 14:54:33 -05001598 do {
Tejun Heoadc5e8b2013-12-11 14:11:54 -05001599 struct rb_node *node = rb_next(&pos->rb);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001600 if (!node)
1601 pos = NULL;
1602 else
Tejun Heo324a56e2013-12-11 14:11:53 -05001603 pos = rb_to_kn(node);
Tejun Heob9c9dad2014-02-03 14:09:11 -05001604 } while (pos && (!kernfs_active(pos) || pos->ns != ns));
1605 }
Tejun Heofd7b9f72013-11-28 14:54:33 -05001606 return pos;
1607}
1608
Tejun Heoc637b8a2013-12-11 14:11:58 -05001609static int kernfs_fop_readdir(struct file *file, struct dir_context *ctx)
Tejun Heofd7b9f72013-11-28 14:54:33 -05001610{
1611 struct dentry *dentry = file->f_path.dentry;
Tejun Heo324a56e2013-12-11 14:11:53 -05001612 struct kernfs_node *parent = dentry->d_fsdata;
1613 struct kernfs_node *pos = file->private_data;
Tejun Heofd7b9f72013-11-28 14:54:33 -05001614 const void *ns = NULL;
1615
1616 if (!dir_emit_dots(file, ctx))
1617 return 0;
Tejun Heoa797bfc2013-12-11 14:11:57 -05001618 mutex_lock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001619
Tejun Heo324a56e2013-12-11 14:11:53 -05001620 if (kernfs_ns_enabled(parent))
Tejun Heoc525aad2013-12-11 14:11:55 -05001621 ns = kernfs_info(dentry->d_sb)->ns;
Tejun Heofd7b9f72013-11-28 14:54:33 -05001622
Tejun Heoc637b8a2013-12-11 14:11:58 -05001623 for (pos = kernfs_dir_pos(ns, parent, ctx->pos, pos);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001624 pos;
Tejun Heoc637b8a2013-12-11 14:11:58 -05001625 pos = kernfs_dir_next_pos(ns, parent, ctx->pos, pos)) {
Tejun Heoadc5e8b2013-12-11 14:11:54 -05001626 const char *name = pos->name;
Tejun Heofd7b9f72013-11-28 14:54:33 -05001627 unsigned int type = dt_type(pos);
1628 int len = strlen(name);
Tejun Heoadc5e8b2013-12-11 14:11:54 -05001629 ino_t ino = pos->ino;
Tejun Heofd7b9f72013-11-28 14:54:33 -05001630
Tejun Heoadc5e8b2013-12-11 14:11:54 -05001631 ctx->pos = pos->hash;
Tejun Heofd7b9f72013-11-28 14:54:33 -05001632 file->private_data = pos;
1633 kernfs_get(pos);
1634
Tejun Heoa797bfc2013-12-11 14:11:57 -05001635 mutex_unlock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001636 if (!dir_emit(ctx, name, len, ino, type))
1637 return 0;
Tejun Heoa797bfc2013-12-11 14:11:57 -05001638 mutex_lock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001639 }
Tejun Heoa797bfc2013-12-11 14:11:57 -05001640 mutex_unlock(&kernfs_mutex);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001641 file->private_data = NULL;
1642 ctx->pos = INT_MAX;
1643 return 0;
1644}
1645
Tejun Heoc637b8a2013-12-11 14:11:58 -05001646static loff_t kernfs_dir_fop_llseek(struct file *file, loff_t offset,
1647 int whence)
Tejun Heofd7b9f72013-11-28 14:54:33 -05001648{
1649 struct inode *inode = file_inode(file);
1650 loff_t ret;
1651
Al Viro59551022016-01-22 15:40:57 -05001652 inode_lock(inode);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001653 ret = generic_file_llseek(file, offset, whence);
Al Viro59551022016-01-22 15:40:57 -05001654 inode_unlock(inode);
Tejun Heofd7b9f72013-11-28 14:54:33 -05001655
1656 return ret;
1657}
1658
Tejun Heoa797bfc2013-12-11 14:11:57 -05001659const struct file_operations kernfs_dir_fops = {
Tejun Heofd7b9f72013-11-28 14:54:33 -05001660 .read = generic_read_dir,
Tejun Heoc637b8a2013-12-11 14:11:58 -05001661 .iterate = kernfs_fop_readdir,
1662 .release = kernfs_dir_fop_release,
1663 .llseek = kernfs_dir_fop_llseek,
Tejun Heofd7b9f72013-11-28 14:54:33 -05001664};