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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Harry Weibd33d122011-07-16 16:45:13 +08002 * inode.c - part of debugfs, a tiny little debug file system
Linus Torvalds1da177e2005-04-16 15:20:36 -07003 *
4 * Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com>
5 * Copyright (C) 2004 IBM Inc.
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License version
9 * 2 as published by the Free Software Foundation.
10 *
11 * debugfs is for people to use instead of /proc or /sys.
12 * See Documentation/DocBook/kernel-api for more details.
13 *
14 */
15
Linus Torvalds1da177e2005-04-16 15:20:36 -070016#include <linux/module.h>
17#include <linux/fs.h>
18#include <linux/mount.h>
19#include <linux/pagemap.h>
20#include <linux/init.h>
Randy Dunlap4d8ebdd2006-11-25 11:09:26 -080021#include <linux/kobject.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070022#include <linux/namei.h>
23#include <linux/debugfs.h>
Mathieu Desnoyers4f365572006-11-24 13:45:37 -050024#include <linux/fsnotify.h>
Peter Oberparleiter66f54962007-02-13 12:13:54 +010025#include <linux/string.h>
Mimi Zohar92562922008-10-07 14:00:12 -040026#include <linux/magic.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090027#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070028
Linus Torvalds1da177e2005-04-16 15:20:36 -070029static struct vfsmount *debugfs_mount;
30static int debugfs_mount_count;
Frederic Weisbeckerc0f92ba2009-03-22 23:10:44 +010031static bool debugfs_registered;
Linus Torvalds1da177e2005-04-16 15:20:36 -070032
Mathieu Desnoyersd3a3b0a2009-11-17 14:40:26 -080033static struct inode *debugfs_get_inode(struct super_block *sb, int mode, dev_t dev,
34 void *data, const struct file_operations *fops)
35
Linus Torvalds1da177e2005-04-16 15:20:36 -070036{
37 struct inode *inode = new_inode(sb);
38
39 if (inode) {
Christoph Hellwig85fe4022010-10-23 11:19:54 -040040 inode->i_ino = get_next_ino();
Linus Torvalds1da177e2005-04-16 15:20:36 -070041 inode->i_mode = mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -070042 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
43 switch (mode & S_IFMT) {
44 default:
45 init_special_inode(inode, mode, dev);
46 break;
47 case S_IFREG:
Mathieu Desnoyersd3a3b0a2009-11-17 14:40:26 -080048 inode->i_fop = fops ? fops : &debugfs_file_operations;
49 inode->i_private = data;
Linus Torvalds1da177e2005-04-16 15:20:36 -070050 break;
Peter Oberparleiter66f54962007-02-13 12:13:54 +010051 case S_IFLNK:
52 inode->i_op = &debugfs_link_operations;
Mathieu Desnoyersd3a3b0a2009-11-17 14:40:26 -080053 inode->i_fop = fops;
54 inode->i_private = data;
Peter Oberparleiter66f54962007-02-13 12:13:54 +010055 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -070056 case S_IFDIR:
57 inode->i_op = &simple_dir_inode_operations;
Mathieu Desnoyersd3a3b0a2009-11-17 14:40:26 -080058 inode->i_fop = fops ? fops : &simple_dir_operations;
59 inode->i_private = data;
Linus Torvalds1da177e2005-04-16 15:20:36 -070060
Mathieu Desnoyersbafb232e2006-11-24 13:46:30 -050061 /* directory inodes start off with i_nlink == 2
62 * (for "." entry) */
Dave Hansend8c76e62006-09-30 23:29:04 -070063 inc_nlink(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -070064 break;
65 }
66 }
67 return inode;
68}
69
70/* SMP-safe */
71static int debugfs_mknod(struct inode *dir, struct dentry *dentry,
Mathieu Desnoyersd3a3b0a2009-11-17 14:40:26 -080072 int mode, dev_t dev, void *data,
73 const struct file_operations *fops)
Linus Torvalds1da177e2005-04-16 15:20:36 -070074{
Jens Axboe71601e2b2006-06-08 10:26:39 +020075 struct inode *inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -070076 int error = -EPERM;
77
78 if (dentry->d_inode)
79 return -EEXIST;
80
Mathieu Desnoyersd3a3b0a2009-11-17 14:40:26 -080081 inode = debugfs_get_inode(dir->i_sb, mode, dev, data, fops);
Linus Torvalds1da177e2005-04-16 15:20:36 -070082 if (inode) {
83 d_instantiate(dentry, inode);
84 dget(dentry);
85 error = 0;
86 }
87 return error;
88}
89
Mathieu Desnoyersd3a3b0a2009-11-17 14:40:26 -080090static int debugfs_mkdir(struct inode *dir, struct dentry *dentry, int mode,
91 void *data, const struct file_operations *fops)
Linus Torvalds1da177e2005-04-16 15:20:36 -070092{
93 int res;
94
95 mode = (mode & (S_IRWXUGO | S_ISVTX)) | S_IFDIR;
Mathieu Desnoyersd3a3b0a2009-11-17 14:40:26 -080096 res = debugfs_mknod(dir, dentry, mode, 0, data, fops);
Mathieu Desnoyers4f365572006-11-24 13:45:37 -050097 if (!res) {
Dave Hansend8c76e62006-09-30 23:29:04 -070098 inc_nlink(dir);
Mathieu Desnoyers4f365572006-11-24 13:45:37 -050099 fsnotify_mkdir(dir, dentry);
100 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101 return res;
102}
103
Mathieu Desnoyersd3a3b0a2009-11-17 14:40:26 -0800104static int debugfs_link(struct inode *dir, struct dentry *dentry, int mode,
105 void *data, const struct file_operations *fops)
Peter Oberparleiter66f54962007-02-13 12:13:54 +0100106{
107 mode = (mode & S_IALLUGO) | S_IFLNK;
Mathieu Desnoyersd3a3b0a2009-11-17 14:40:26 -0800108 return debugfs_mknod(dir, dentry, mode, 0, data, fops);
Peter Oberparleiter66f54962007-02-13 12:13:54 +0100109}
110
Mathieu Desnoyersd3a3b0a2009-11-17 14:40:26 -0800111static int debugfs_create(struct inode *dir, struct dentry *dentry, int mode,
112 void *data, const struct file_operations *fops)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113{
Mathieu Desnoyers4f365572006-11-24 13:45:37 -0500114 int res;
115
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116 mode = (mode & S_IALLUGO) | S_IFREG;
Mathieu Desnoyersd3a3b0a2009-11-17 14:40:26 -0800117 res = debugfs_mknod(dir, dentry, mode, 0, data, fops);
Mathieu Desnoyers4f365572006-11-24 13:45:37 -0500118 if (!res)
119 fsnotify_create(dir, dentry);
120 return res;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121}
122
123static inline int debugfs_positive(struct dentry *dentry)
124{
125 return dentry->d_inode && !d_unhashed(dentry);
126}
127
128static int debug_fill_super(struct super_block *sb, void *data, int silent)
129{
130 static struct tree_descr debug_files[] = {{""}};
131
132 return simple_fill_super(sb, DEBUGFS_MAGIC, debug_files);
133}
134
Al Virofc14f2f2010-07-25 01:48:30 +0400135static struct dentry *debug_mount(struct file_system_type *fs_type,
David Howells454e2392006-06-23 02:02:57 -0700136 int flags, const char *dev_name,
Al Virofc14f2f2010-07-25 01:48:30 +0400137 void *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138{
Al Virofc14f2f2010-07-25 01:48:30 +0400139 return mount_single(fs_type, flags, data, debug_fill_super);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140}
141
142static struct file_system_type debug_fs_type = {
143 .owner = THIS_MODULE,
144 .name = "debugfs",
Al Virofc14f2f2010-07-25 01:48:30 +0400145 .mount = debug_mount,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146 .kill_sb = kill_litter_super,
147};
148
149static int debugfs_create_by_name(const char *name, mode_t mode,
150 struct dentry *parent,
Mathieu Desnoyersd3a3b0a2009-11-17 14:40:26 -0800151 struct dentry **dentry,
152 void *data,
153 const struct file_operations *fops)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154{
155 int error = 0;
156
157 /* If the parent is not specified, we create it in the root.
158 * We need the root dentry to do this, which is in the super
159 * block. A pointer to that is in the struct vfsmount that we
160 * have around.
161 */
Al Viroef52c752010-01-25 04:50:43 -0500162 if (!parent)
163 parent = debugfs_mount->mnt_sb->s_root;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164
165 *dentry = NULL;
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800166 mutex_lock(&parent->d_inode->i_mutex);
Christoph Hellwig5f45f1a2005-06-23 00:09:12 -0700167 *dentry = lookup_one_len(name, parent, strlen(name));
Akinobu Mita7bb03862006-10-19 12:24:42 +0900168 if (!IS_ERR(*dentry)) {
Peter Oberparleiter66f54962007-02-13 12:13:54 +0100169 switch (mode & S_IFMT) {
170 case S_IFDIR:
Mathieu Desnoyersd3a3b0a2009-11-17 14:40:26 -0800171 error = debugfs_mkdir(parent->d_inode, *dentry, mode,
172 data, fops);
Peter Oberparleiter66f54962007-02-13 12:13:54 +0100173 break;
174 case S_IFLNK:
Mathieu Desnoyersd3a3b0a2009-11-17 14:40:26 -0800175 error = debugfs_link(parent->d_inode, *dentry, mode,
176 data, fops);
Peter Oberparleiter66f54962007-02-13 12:13:54 +0100177 break;
178 default:
Mathieu Desnoyersd3a3b0a2009-11-17 14:40:26 -0800179 error = debugfs_create(parent->d_inode, *dentry, mode,
180 data, fops);
Peter Oberparleiter66f54962007-02-13 12:13:54 +0100181 break;
182 }
Mathieu Desnoyers65c33332006-11-24 13:50:09 -0500183 dput(*dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184 } else
Akinobu Mita7bb03862006-10-19 12:24:42 +0900185 error = PTR_ERR(*dentry);
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800186 mutex_unlock(&parent->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187
188 return error;
189}
190
191/**
192 * debugfs_create_file - create a file in the debugfs filesystem
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193 * @name: a pointer to a string containing the name of the file to create.
Alberto Bertoglibe030e62009-10-31 18:26:52 -0300194 * @mode: the permission that the file should have.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700195 * @parent: a pointer to the parent dentry for this file. This should be a
196 * directory dentry if set. If this paramater is NULL, then the
197 * file will be created in the root of the debugfs filesystem.
198 * @data: a pointer to something that the caller will want to get to later
Theodore Ts'o8e18e292006-09-27 01:50:46 -0700199 * on. The inode.i_private pointer will point to this value on
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200 * the open() call.
201 * @fops: a pointer to a struct file_operations that should be used for
202 * this file.
203 *
204 * This is the basic "create a file" function for debugfs. It allows for a
Alberto Bertoglibe030e62009-10-31 18:26:52 -0300205 * wide range of flexibility in creating a file, or a directory (if you want
206 * to create a directory, the debugfs_create_dir() function is
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207 * recommended to be used instead.)
208 *
209 * This function will return a pointer to a dentry if it succeeds. This
210 * pointer must be passed to the debugfs_remove() function when the file is
211 * to be removed (no automatic cleanup happens if your module is unloaded,
Randy Dunlap6468b3a2006-07-20 08:16:42 -0700212 * you are responsible here.) If an error occurs, %NULL will be returned.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213 *
Randy Dunlap6468b3a2006-07-20 08:16:42 -0700214 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
Cornelia Huck873760f2007-02-14 07:57:47 +0100215 * returned.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216 */
217struct dentry *debugfs_create_file(const char *name, mode_t mode,
218 struct dentry *parent, void *data,
Arjan van de Ven99ac48f2006-03-28 01:56:41 -0800219 const struct file_operations *fops)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220{
221 struct dentry *dentry = NULL;
222 int error;
223
224 pr_debug("debugfs: creating file '%s'\n",name);
225
Mathieu Desnoyers63223a02006-11-24 13:48:19 -0500226 error = simple_pin_fs(&debug_fs_type, &debugfs_mount,
227 &debugfs_mount_count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228 if (error)
229 goto exit;
230
Mathieu Desnoyersd3a3b0a2009-11-17 14:40:26 -0800231 error = debugfs_create_by_name(name, mode, parent, &dentry,
232 data, fops);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700233 if (error) {
234 dentry = NULL;
Mathieu Desnoyers63223a02006-11-24 13:48:19 -0500235 simple_release_fs(&debugfs_mount, &debugfs_mount_count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236 goto exit;
237 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700238exit:
239 return dentry;
240}
241EXPORT_SYMBOL_GPL(debugfs_create_file);
242
243/**
244 * debugfs_create_dir - create a directory in the debugfs filesystem
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245 * @name: a pointer to a string containing the name of the directory to
246 * create.
247 * @parent: a pointer to the parent dentry for this file. This should be a
248 * directory dentry if set. If this paramater is NULL, then the
249 * directory will be created in the root of the debugfs filesystem.
250 *
251 * This function creates a directory in debugfs with the given name.
252 *
253 * This function will return a pointer to a dentry if it succeeds. This
254 * pointer must be passed to the debugfs_remove() function when the file is
255 * to be removed (no automatic cleanup happens if your module is unloaded,
Randy Dunlap6468b3a2006-07-20 08:16:42 -0700256 * you are responsible here.) If an error occurs, %NULL will be returned.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257 *
Randy Dunlap6468b3a2006-07-20 08:16:42 -0700258 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
Cornelia Huck873760f2007-02-14 07:57:47 +0100259 * returned.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260 */
261struct dentry *debugfs_create_dir(const char *name, struct dentry *parent)
262{
263 return debugfs_create_file(name,
264 S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
265 parent, NULL, NULL);
266}
267EXPORT_SYMBOL_GPL(debugfs_create_dir);
268
269/**
Peter Oberparleiter66f54962007-02-13 12:13:54 +0100270 * debugfs_create_symlink- create a symbolic link in the debugfs filesystem
271 * @name: a pointer to a string containing the name of the symbolic link to
272 * create.
273 * @parent: a pointer to the parent dentry for this symbolic link. This
274 * should be a directory dentry if set. If this paramater is NULL,
275 * then the symbolic link will be created in the root of the debugfs
276 * filesystem.
277 * @target: a pointer to a string containing the path to the target of the
278 * symbolic link.
279 *
280 * This function creates a symbolic link with the given name in debugfs that
281 * links to the given target path.
282 *
283 * This function will return a pointer to a dentry if it succeeds. This
284 * pointer must be passed to the debugfs_remove() function when the symbolic
285 * link is to be removed (no automatic cleanup happens if your module is
286 * unloaded, you are responsible here.) If an error occurs, %NULL will be
287 * returned.
288 *
289 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
Cornelia Huck873760f2007-02-14 07:57:47 +0100290 * returned.
Peter Oberparleiter66f54962007-02-13 12:13:54 +0100291 */
292struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent,
293 const char *target)
294{
295 struct dentry *result;
296 char *link;
297
298 link = kstrdup(target, GFP_KERNEL);
299 if (!link)
300 return NULL;
301
302 result = debugfs_create_file(name, S_IFLNK | S_IRWXUGO, parent, link,
303 NULL);
304 if (!result)
305 kfree(link);
306 return result;
307}
308EXPORT_SYMBOL_GPL(debugfs_create_symlink);
309
Jan Kara25d41d82011-02-07 15:00:27 +0100310static int __debugfs_remove(struct dentry *dentry, struct dentry *parent)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311{
Mathieu Desnoyers65c33332006-11-24 13:50:09 -0500312 int ret = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313
Linus Torvalds1da177e2005-04-16 15:20:36 -0700314 if (debugfs_positive(dentry)) {
315 if (dentry->d_inode) {
Mathieu Desnoyers29a7f3a2006-11-24 13:51:14 -0500316 dget(dentry);
Peter Oberparleiter66f54962007-02-13 12:13:54 +0100317 switch (dentry->d_inode->i_mode & S_IFMT) {
318 case S_IFDIR:
Mathieu Desnoyers65c33332006-11-24 13:50:09 -0500319 ret = simple_rmdir(parent->d_inode, dentry);
Peter Oberparleiter66f54962007-02-13 12:13:54 +0100320 break;
321 case S_IFLNK:
322 kfree(dentry->d_inode->i_private);
323 /* fall through */
324 default:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700325 simple_unlink(parent->d_inode, dentry);
Peter Oberparleiter66f54962007-02-13 12:13:54 +0100326 break;
327 }
Mathieu Desnoyers29a7f3a2006-11-24 13:51:14 -0500328 if (!ret)
329 d_delete(dentry);
330 dput(dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700331 }
332 }
Jan Kara25d41d82011-02-07 15:00:27 +0100333 return ret;
Haavard Skinnemoen9505e632008-07-01 15:14:51 +0200334}
335
336/**
337 * debugfs_remove - removes a file or directory from the debugfs filesystem
338 * @dentry: a pointer to a the dentry of the file or directory to be
339 * removed.
340 *
341 * This function removes a file or directory in debugfs that was previously
342 * created with a call to another debugfs function (like
343 * debugfs_create_file() or variants thereof.)
344 *
345 * This function is required to be called in order for the file to be
346 * removed, no automatic cleanup of files will happen when a module is
347 * removed, you are responsible here.
348 */
349void debugfs_remove(struct dentry *dentry)
350{
351 struct dentry *parent;
Jan Kara25d41d82011-02-07 15:00:27 +0100352 int ret;
353
Haavard Skinnemoen9505e632008-07-01 15:14:51 +0200354 if (!dentry)
355 return;
356
357 parent = dentry->d_parent;
358 if (!parent || !parent->d_inode)
359 return;
360
361 mutex_lock(&parent->d_inode->i_mutex);
Jan Kara25d41d82011-02-07 15:00:27 +0100362 ret = __debugfs_remove(dentry, parent);
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800363 mutex_unlock(&parent->d_inode->i_mutex);
Jan Kara25d41d82011-02-07 15:00:27 +0100364 if (!ret)
365 simple_release_fs(&debugfs_mount, &debugfs_mount_count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700366}
367EXPORT_SYMBOL_GPL(debugfs_remove);
368
Jan Karacfc94cd2007-05-09 13:19:52 +0200369/**
Haavard Skinnemoen9505e632008-07-01 15:14:51 +0200370 * debugfs_remove_recursive - recursively removes a directory
371 * @dentry: a pointer to a the dentry of the directory to be removed.
372 *
373 * This function recursively removes a directory tree in debugfs that
374 * was previously created with a call to another debugfs function
375 * (like debugfs_create_file() or variants thereof.)
376 *
377 * This function is required to be called in order for the file to be
378 * removed, no automatic cleanup of files will happen when a module is
379 * removed, you are responsible here.
380 */
381void debugfs_remove_recursive(struct dentry *dentry)
382{
383 struct dentry *child;
384 struct dentry *parent;
385
386 if (!dentry)
387 return;
388
389 parent = dentry->d_parent;
390 if (!parent || !parent->d_inode)
391 return;
392
393 parent = dentry;
394 mutex_lock(&parent->d_inode->i_mutex);
395
396 while (1) {
397 /*
398 * When all dentries under "parent" has been removed,
399 * walk up the tree until we reach our starting point.
400 */
401 if (list_empty(&parent->d_subdirs)) {
402 mutex_unlock(&parent->d_inode->i_mutex);
403 if (parent == dentry)
404 break;
405 parent = parent->d_parent;
406 mutex_lock(&parent->d_inode->i_mutex);
407 }
408 child = list_entry(parent->d_subdirs.next, struct dentry,
409 d_u.d_child);
Steven Rostedt56a83cc2009-04-25 00:39:40 -0400410 next_sibling:
Haavard Skinnemoen9505e632008-07-01 15:14:51 +0200411
412 /*
413 * If "child" isn't empty, walk down the tree and
414 * remove all its descendants first.
415 */
416 if (!list_empty(&child->d_subdirs)) {
417 mutex_unlock(&parent->d_inode->i_mutex);
418 parent = child;
419 mutex_lock(&parent->d_inode->i_mutex);
420 continue;
421 }
422 __debugfs_remove(child, parent);
423 if (parent->d_subdirs.next == &child->d_u.d_child) {
424 /*
Steven Rostedt56a83cc2009-04-25 00:39:40 -0400425 * Try the next sibling.
426 */
427 if (child->d_u.d_child.next != &parent->d_subdirs) {
428 child = list_entry(child->d_u.d_child.next,
429 struct dentry,
430 d_u.d_child);
431 goto next_sibling;
432 }
433
434 /*
Haavard Skinnemoen9505e632008-07-01 15:14:51 +0200435 * Avoid infinite loop if we fail to remove
436 * one dentry.
437 */
438 mutex_unlock(&parent->d_inode->i_mutex);
439 break;
440 }
441 simple_release_fs(&debugfs_mount, &debugfs_mount_count);
442 }
443
444 parent = dentry->d_parent;
445 mutex_lock(&parent->d_inode->i_mutex);
446 __debugfs_remove(dentry, parent);
447 mutex_unlock(&parent->d_inode->i_mutex);
448 simple_release_fs(&debugfs_mount, &debugfs_mount_count);
449}
450EXPORT_SYMBOL_GPL(debugfs_remove_recursive);
451
452/**
Jan Karacfc94cd2007-05-09 13:19:52 +0200453 * debugfs_rename - rename a file/directory in the debugfs filesystem
454 * @old_dir: a pointer to the parent dentry for the renamed object. This
455 * should be a directory dentry.
456 * @old_dentry: dentry of an object to be renamed.
457 * @new_dir: a pointer to the parent dentry where the object should be
458 * moved. This should be a directory dentry.
459 * @new_name: a pointer to a string containing the target name.
460 *
461 * This function renames a file/directory in debugfs. The target must not
462 * exist for rename to succeed.
463 *
464 * This function will return a pointer to old_dentry (which is updated to
465 * reflect renaming) if it succeeds. If an error occurs, %NULL will be
466 * returned.
467 *
468 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
469 * returned.
470 */
471struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry,
472 struct dentry *new_dir, const char *new_name)
473{
474 int error;
475 struct dentry *dentry = NULL, *trap;
476 const char *old_name;
477
478 trap = lock_rename(new_dir, old_dir);
479 /* Source or destination directories don't exist? */
480 if (!old_dir->d_inode || !new_dir->d_inode)
481 goto exit;
482 /* Source does not exist, cyclic rename, or mountpoint? */
483 if (!old_dentry->d_inode || old_dentry == trap ||
484 d_mountpoint(old_dentry))
485 goto exit;
486 dentry = lookup_one_len(new_name, new_dir, strlen(new_name));
487 /* Lookup failed, cyclic rename or target exists? */
488 if (IS_ERR(dentry) || dentry == trap || dentry->d_inode)
489 goto exit;
490
491 old_name = fsnotify_oldname_init(old_dentry->d_name.name);
492
493 error = simple_rename(old_dir->d_inode, old_dentry, new_dir->d_inode,
494 dentry);
495 if (error) {
496 fsnotify_oldname_free(old_name);
497 goto exit;
498 }
499 d_move(old_dentry, dentry);
500 fsnotify_move(old_dir->d_inode, new_dir->d_inode, old_name,
Al Viro123df292009-12-25 04:57:57 -0500501 S_ISDIR(old_dentry->d_inode->i_mode),
Al Viro5a190ae2007-06-07 12:19:32 -0400502 NULL, old_dentry);
Jan Karacfc94cd2007-05-09 13:19:52 +0200503 fsnotify_oldname_free(old_name);
504 unlock_rename(new_dir, old_dir);
505 dput(dentry);
506 return old_dentry;
507exit:
508 if (dentry && !IS_ERR(dentry))
509 dput(dentry);
510 unlock_rename(new_dir, old_dir);
511 return NULL;
512}
513EXPORT_SYMBOL_GPL(debugfs_rename);
514
Frederic Weisbeckerc0f92ba2009-03-22 23:10:44 +0100515/**
516 * debugfs_initialized - Tells whether debugfs has been registered
517 */
518bool debugfs_initialized(void)
519{
520 return debugfs_registered;
521}
522EXPORT_SYMBOL_GPL(debugfs_initialized);
523
524
Greg Kroah-Hartman191e1862007-10-29 20:13:17 +0100525static struct kobject *debug_kobj;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700526
527static int __init debugfs_init(void)
528{
529 int retval;
530
Greg Kroah-Hartman0ff21e42007-11-06 10:36:58 -0800531 debug_kobj = kobject_create_and_add("debug", kernel_kobj);
Greg Kroah-Hartman191e1862007-10-29 20:13:17 +0100532 if (!debug_kobj)
533 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700534
535 retval = register_filesystem(&debug_fs_type);
536 if (retval)
Greg Kroah-Hartman197b12d2007-12-20 08:13:05 -0800537 kobject_put(debug_kobj);
Frederic Weisbeckerc0f92ba2009-03-22 23:10:44 +0100538 else
539 debugfs_registered = true;
540
Linus Torvalds1da177e2005-04-16 15:20:36 -0700541 return retval;
542}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543core_initcall(debugfs_init);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700544