blob: b486169f42bf997e9e620f12996f7711070140e2 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * file.c - part of debugfs, a tiny little debug file system
3 *
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
16/* uncomment to get debug messages from the debug filesystem, ah the irony. */
17/* #define DEBUG */
18
Linus Torvalds1da177e2005-04-16 15:20:36 -070019#include <linux/module.h>
20#include <linux/fs.h>
21#include <linux/mount.h>
22#include <linux/pagemap.h>
23#include <linux/init.h>
Randy Dunlap4d8ebdd2006-11-25 11:09:26 -080024#include <linux/kobject.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070025#include <linux/namei.h>
26#include <linux/debugfs.h>
Mathieu Desnoyers4f365572006-11-24 13:45:37 -050027#include <linux/fsnotify.h>
Peter Oberparleiter66f54962007-02-13 12:13:54 +010028#include <linux/string.h>
Mimi Zohar92562922008-10-07 14:00:12 -040029#include <linux/magic.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070030
Linus Torvalds1da177e2005-04-16 15:20:36 -070031static struct vfsmount *debugfs_mount;
32static int debugfs_mount_count;
Frederic Weisbeckerc0f92ba2009-03-22 23:10:44 +010033static bool debugfs_registered;
Linus Torvalds1da177e2005-04-16 15:20:36 -070034
Mathieu Desnoyersd3a3b0a2009-11-17 14:40:26 -080035static struct inode *debugfs_get_inode(struct super_block *sb, int mode, dev_t dev,
36 void *data, const struct file_operations *fops)
37
Linus Torvalds1da177e2005-04-16 15:20:36 -070038{
39 struct inode *inode = new_inode(sb);
40
41 if (inode) {
42 inode->i_mode = mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -070043 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
44 switch (mode & S_IFMT) {
45 default:
46 init_special_inode(inode, mode, dev);
47 break;
48 case S_IFREG:
Mathieu Desnoyersd3a3b0a2009-11-17 14:40:26 -080049 inode->i_fop = fops ? fops : &debugfs_file_operations;
50 inode->i_private = data;
Linus Torvalds1da177e2005-04-16 15:20:36 -070051 break;
Peter Oberparleiter66f54962007-02-13 12:13:54 +010052 case S_IFLNK:
53 inode->i_op = &debugfs_link_operations;
Mathieu Desnoyersd3a3b0a2009-11-17 14:40:26 -080054 inode->i_fop = fops;
55 inode->i_private = data;
Peter Oberparleiter66f54962007-02-13 12:13:54 +010056 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -070057 case S_IFDIR:
58 inode->i_op = &simple_dir_inode_operations;
Mathieu Desnoyersd3a3b0a2009-11-17 14:40:26 -080059 inode->i_fop = fops ? fops : &simple_dir_operations;
60 inode->i_private = data;
Linus Torvalds1da177e2005-04-16 15:20:36 -070061
Mathieu Desnoyersbafb2322006-11-24 13:46:30 -050062 /* directory inodes start off with i_nlink == 2
63 * (for "." entry) */
Dave Hansend8c76e62006-09-30 23:29:04 -070064 inc_nlink(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -070065 break;
66 }
67 }
68 return inode;
69}
70
71/* SMP-safe */
72static int debugfs_mknod(struct inode *dir, struct dentry *dentry,
Mathieu Desnoyersd3a3b0a2009-11-17 14:40:26 -080073 int mode, dev_t dev, void *data,
74 const struct file_operations *fops)
Linus Torvalds1da177e2005-04-16 15:20:36 -070075{
Jens Axboe71601e22006-06-08 10:26:39 +020076 struct inode *inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -070077 int error = -EPERM;
78
79 if (dentry->d_inode)
80 return -EEXIST;
81
Mathieu Desnoyersd3a3b0a2009-11-17 14:40:26 -080082 inode = debugfs_get_inode(dir->i_sb, mode, dev, data, fops);
Linus Torvalds1da177e2005-04-16 15:20:36 -070083 if (inode) {
84 d_instantiate(dentry, inode);
85 dget(dentry);
86 error = 0;
87 }
88 return error;
89}
90
Mathieu Desnoyersd3a3b0a2009-11-17 14:40:26 -080091static int debugfs_mkdir(struct inode *dir, struct dentry *dentry, int mode,
92 void *data, const struct file_operations *fops)
Linus Torvalds1da177e2005-04-16 15:20:36 -070093{
94 int res;
95
96 mode = (mode & (S_IRWXUGO | S_ISVTX)) | S_IFDIR;
Mathieu Desnoyersd3a3b0a2009-11-17 14:40:26 -080097 res = debugfs_mknod(dir, dentry, mode, 0, data, fops);
Mathieu Desnoyers4f365572006-11-24 13:45:37 -050098 if (!res) {
Dave Hansend8c76e62006-09-30 23:29:04 -070099 inc_nlink(dir);
Mathieu Desnoyers4f365572006-11-24 13:45:37 -0500100 fsnotify_mkdir(dir, dentry);
101 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102 return res;
103}
104
Mathieu Desnoyersd3a3b0a2009-11-17 14:40:26 -0800105static int debugfs_link(struct inode *dir, struct dentry *dentry, int mode,
106 void *data, const struct file_operations *fops)
Peter Oberparleiter66f54962007-02-13 12:13:54 +0100107{
108 mode = (mode & S_IALLUGO) | S_IFLNK;
Mathieu Desnoyersd3a3b0a2009-11-17 14:40:26 -0800109 return debugfs_mknod(dir, dentry, mode, 0, data, fops);
Peter Oberparleiter66f54962007-02-13 12:13:54 +0100110}
111
Mathieu Desnoyersd3a3b0a2009-11-17 14:40:26 -0800112static int debugfs_create(struct inode *dir, struct dentry *dentry, int mode,
113 void *data, const struct file_operations *fops)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114{
Mathieu Desnoyers4f365572006-11-24 13:45:37 -0500115 int res;
116
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117 mode = (mode & S_IALLUGO) | S_IFREG;
Mathieu Desnoyersd3a3b0a2009-11-17 14:40:26 -0800118 res = debugfs_mknod(dir, dentry, mode, 0, data, fops);
Mathieu Desnoyers4f365572006-11-24 13:45:37 -0500119 if (!res)
120 fsnotify_create(dir, dentry);
121 return res;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700122}
123
124static inline int debugfs_positive(struct dentry *dentry)
125{
126 return dentry->d_inode && !d_unhashed(dentry);
127}
128
129static int debug_fill_super(struct super_block *sb, void *data, int silent)
130{
131 static struct tree_descr debug_files[] = {{""}};
132
133 return simple_fill_super(sb, DEBUGFS_MAGIC, debug_files);
134}
135
David Howells454e2392006-06-23 02:02:57 -0700136static int debug_get_sb(struct file_system_type *fs_type,
137 int flags, const char *dev_name,
138 void *data, struct vfsmount *mnt)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139{
David Howells454e2392006-06-23 02:02:57 -0700140 return get_sb_single(fs_type, flags, data, debug_fill_super, mnt);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141}
142
143static struct file_system_type debug_fs_type = {
144 .owner = THIS_MODULE,
145 .name = "debugfs",
146 .get_sb = debug_get_sb,
147 .kill_sb = kill_litter_super,
148};
149
150static int debugfs_create_by_name(const char *name, mode_t mode,
151 struct dentry *parent,
Mathieu Desnoyersd3a3b0a2009-11-17 14:40:26 -0800152 struct dentry **dentry,
153 void *data,
154 const struct file_operations *fops)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155{
156 int error = 0;
157
158 /* If the parent is not specified, we create it in the root.
159 * We need the root dentry to do this, which is in the super
160 * block. A pointer to that is in the struct vfsmount that we
161 * have around.
162 */
Mathieu Desnoyersbafb2322006-11-24 13:46:30 -0500163 if (!parent) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164 if (debugfs_mount && debugfs_mount->mnt_sb) {
165 parent = debugfs_mount->mnt_sb->s_root;
166 }
167 }
168 if (!parent) {
169 pr_debug("debugfs: Ah! can not find a parent!\n");
170 return -EFAULT;
171 }
172
173 *dentry = NULL;
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800174 mutex_lock(&parent->d_inode->i_mutex);
Christoph Hellwig5f45f1a2005-06-23 00:09:12 -0700175 *dentry = lookup_one_len(name, parent, strlen(name));
Akinobu Mita7bb03862006-10-19 12:24:42 +0900176 if (!IS_ERR(*dentry)) {
Peter Oberparleiter66f54962007-02-13 12:13:54 +0100177 switch (mode & S_IFMT) {
178 case S_IFDIR:
Mathieu Desnoyersd3a3b0a2009-11-17 14:40:26 -0800179 error = debugfs_mkdir(parent->d_inode, *dentry, mode,
180 data, fops);
Peter Oberparleiter66f54962007-02-13 12:13:54 +0100181 break;
182 case S_IFLNK:
Mathieu Desnoyersd3a3b0a2009-11-17 14:40:26 -0800183 error = debugfs_link(parent->d_inode, *dentry, mode,
184 data, fops);
Peter Oberparleiter66f54962007-02-13 12:13:54 +0100185 break;
186 default:
Mathieu Desnoyersd3a3b0a2009-11-17 14:40:26 -0800187 error = debugfs_create(parent->d_inode, *dentry, mode,
188 data, fops);
Peter Oberparleiter66f54962007-02-13 12:13:54 +0100189 break;
190 }
Mathieu Desnoyers65c33332006-11-24 13:50:09 -0500191 dput(*dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192 } else
Akinobu Mita7bb03862006-10-19 12:24:42 +0900193 error = PTR_ERR(*dentry);
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800194 mutex_unlock(&parent->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700195
196 return error;
197}
198
199/**
200 * debugfs_create_file - create a file in the debugfs filesystem
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201 * @name: a pointer to a string containing the name of the file to create.
Alberto Bertoglibe030e62009-10-31 18:26:52 -0300202 * @mode: the permission that the file should have.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203 * @parent: a pointer to the parent dentry for this file. This should be a
204 * directory dentry if set. If this paramater is NULL, then the
205 * file will be created in the root of the debugfs filesystem.
206 * @data: a pointer to something that the caller will want to get to later
Theodore Ts'o8e18e292006-09-27 01:50:46 -0700207 * on. The inode.i_private pointer will point to this value on
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208 * the open() call.
209 * @fops: a pointer to a struct file_operations that should be used for
210 * this file.
211 *
212 * This is the basic "create a file" function for debugfs. It allows for a
Alberto Bertoglibe030e62009-10-31 18:26:52 -0300213 * wide range of flexibility in creating a file, or a directory (if you want
214 * to create a directory, the debugfs_create_dir() function is
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215 * recommended to be used instead.)
216 *
217 * This function will return a pointer to a dentry if it succeeds. This
218 * pointer must be passed to the debugfs_remove() function when the file is
219 * to be removed (no automatic cleanup happens if your module is unloaded,
Randy Dunlap6468b3a2006-07-20 08:16:42 -0700220 * you are responsible here.) If an error occurs, %NULL will be returned.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221 *
Randy Dunlap6468b3a2006-07-20 08:16:42 -0700222 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
Cornelia Huck873760f2007-02-14 07:57:47 +0100223 * returned.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224 */
225struct dentry *debugfs_create_file(const char *name, mode_t mode,
226 struct dentry *parent, void *data,
Arjan van de Ven99ac48f2006-03-28 01:56:41 -0800227 const struct file_operations *fops)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228{
229 struct dentry *dentry = NULL;
230 int error;
231
232 pr_debug("debugfs: creating file '%s'\n",name);
233
Mathieu Desnoyers63223a02006-11-24 13:48:19 -0500234 error = simple_pin_fs(&debug_fs_type, &debugfs_mount,
235 &debugfs_mount_count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236 if (error)
237 goto exit;
238
Mathieu Desnoyersd3a3b0a2009-11-17 14:40:26 -0800239 error = debugfs_create_by_name(name, mode, parent, &dentry,
240 data, fops);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700241 if (error) {
242 dentry = NULL;
Mathieu Desnoyers63223a02006-11-24 13:48:19 -0500243 simple_release_fs(&debugfs_mount, &debugfs_mount_count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244 goto exit;
245 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246exit:
247 return dentry;
248}
249EXPORT_SYMBOL_GPL(debugfs_create_file);
250
251/**
252 * debugfs_create_dir - create a directory in the debugfs filesystem
Linus Torvalds1da177e2005-04-16 15:20:36 -0700253 * @name: a pointer to a string containing the name of the directory to
254 * create.
255 * @parent: a pointer to the parent dentry for this file. This should be a
256 * directory dentry if set. If this paramater is NULL, then the
257 * directory will be created in the root of the debugfs filesystem.
258 *
259 * This function creates a directory in debugfs with the given name.
260 *
261 * This function will return a pointer to a dentry if it succeeds. This
262 * pointer must be passed to the debugfs_remove() function when the file is
263 * to be removed (no automatic cleanup happens if your module is unloaded,
Randy Dunlap6468b3a2006-07-20 08:16:42 -0700264 * you are responsible here.) If an error occurs, %NULL will be returned.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700265 *
Randy Dunlap6468b3a2006-07-20 08:16:42 -0700266 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
Cornelia Huck873760f2007-02-14 07:57:47 +0100267 * returned.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268 */
269struct dentry *debugfs_create_dir(const char *name, struct dentry *parent)
270{
271 return debugfs_create_file(name,
272 S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
273 parent, NULL, NULL);
274}
275EXPORT_SYMBOL_GPL(debugfs_create_dir);
276
277/**
Peter Oberparleiter66f54962007-02-13 12:13:54 +0100278 * debugfs_create_symlink- create a symbolic link in the debugfs filesystem
279 * @name: a pointer to a string containing the name of the symbolic link to
280 * create.
281 * @parent: a pointer to the parent dentry for this symbolic link. This
282 * should be a directory dentry if set. If this paramater is NULL,
283 * then the symbolic link will be created in the root of the debugfs
284 * filesystem.
285 * @target: a pointer to a string containing the path to the target of the
286 * symbolic link.
287 *
288 * This function creates a symbolic link with the given name in debugfs that
289 * links to the given target path.
290 *
291 * This function will return a pointer to a dentry if it succeeds. This
292 * pointer must be passed to the debugfs_remove() function when the symbolic
293 * link is to be removed (no automatic cleanup happens if your module is
294 * unloaded, you are responsible here.) If an error occurs, %NULL will be
295 * returned.
296 *
297 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
Cornelia Huck873760f2007-02-14 07:57:47 +0100298 * returned.
Peter Oberparleiter66f54962007-02-13 12:13:54 +0100299 */
300struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent,
301 const char *target)
302{
303 struct dentry *result;
304 char *link;
305
306 link = kstrdup(target, GFP_KERNEL);
307 if (!link)
308 return NULL;
309
310 result = debugfs_create_file(name, S_IFLNK | S_IRWXUGO, parent, link,
311 NULL);
312 if (!result)
313 kfree(link);
314 return result;
315}
316EXPORT_SYMBOL_GPL(debugfs_create_symlink);
317
Haavard Skinnemoen9505e632008-07-01 15:14:51 +0200318static void __debugfs_remove(struct dentry *dentry, struct dentry *parent)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700319{
Mathieu Desnoyers65c33332006-11-24 13:50:09 -0500320 int ret = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321
Linus Torvalds1da177e2005-04-16 15:20:36 -0700322 if (debugfs_positive(dentry)) {
323 if (dentry->d_inode) {
Mathieu Desnoyers29a7f3a2006-11-24 13:51:14 -0500324 dget(dentry);
Peter Oberparleiter66f54962007-02-13 12:13:54 +0100325 switch (dentry->d_inode->i_mode & S_IFMT) {
326 case S_IFDIR:
Mathieu Desnoyers65c33332006-11-24 13:50:09 -0500327 ret = simple_rmdir(parent->d_inode, dentry);
Peter Oberparleiter66f54962007-02-13 12:13:54 +0100328 break;
329 case S_IFLNK:
330 kfree(dentry->d_inode->i_private);
331 /* fall through */
332 default:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333 simple_unlink(parent->d_inode, dentry);
Peter Oberparleiter66f54962007-02-13 12:13:54 +0100334 break;
335 }
Mathieu Desnoyers29a7f3a2006-11-24 13:51:14 -0500336 if (!ret)
337 d_delete(dentry);
338 dput(dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700339 }
340 }
Haavard Skinnemoen9505e632008-07-01 15:14:51 +0200341}
342
343/**
344 * debugfs_remove - removes a file or directory from the debugfs filesystem
345 * @dentry: a pointer to a the dentry of the file or directory to be
346 * removed.
347 *
348 * This function removes a file or directory in debugfs that was previously
349 * created with a call to another debugfs function (like
350 * debugfs_create_file() or variants thereof.)
351 *
352 * This function is required to be called in order for the file to be
353 * removed, no automatic cleanup of files will happen when a module is
354 * removed, you are responsible here.
355 */
356void debugfs_remove(struct dentry *dentry)
357{
358 struct dentry *parent;
359
360 if (!dentry)
361 return;
362
363 parent = dentry->d_parent;
364 if (!parent || !parent->d_inode)
365 return;
366
367 mutex_lock(&parent->d_inode->i_mutex);
368 __debugfs_remove(dentry, parent);
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800369 mutex_unlock(&parent->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700370 simple_release_fs(&debugfs_mount, &debugfs_mount_count);
371}
372EXPORT_SYMBOL_GPL(debugfs_remove);
373
Jan Karacfc94cd2007-05-09 13:19:52 +0200374/**
Haavard Skinnemoen9505e632008-07-01 15:14:51 +0200375 * debugfs_remove_recursive - recursively removes a directory
376 * @dentry: a pointer to a the dentry of the directory to be removed.
377 *
378 * This function recursively removes a directory tree in debugfs that
379 * was previously created with a call to another debugfs function
380 * (like debugfs_create_file() or variants thereof.)
381 *
382 * This function is required to be called in order for the file to be
383 * removed, no automatic cleanup of files will happen when a module is
384 * removed, you are responsible here.
385 */
386void debugfs_remove_recursive(struct dentry *dentry)
387{
388 struct dentry *child;
389 struct dentry *parent;
390
391 if (!dentry)
392 return;
393
394 parent = dentry->d_parent;
395 if (!parent || !parent->d_inode)
396 return;
397
398 parent = dentry;
399 mutex_lock(&parent->d_inode->i_mutex);
400
401 while (1) {
402 /*
403 * When all dentries under "parent" has been removed,
404 * walk up the tree until we reach our starting point.
405 */
406 if (list_empty(&parent->d_subdirs)) {
407 mutex_unlock(&parent->d_inode->i_mutex);
408 if (parent == dentry)
409 break;
410 parent = parent->d_parent;
411 mutex_lock(&parent->d_inode->i_mutex);
412 }
413 child = list_entry(parent->d_subdirs.next, struct dentry,
414 d_u.d_child);
Steven Rostedt56a83cc2009-04-25 00:39:40 -0400415 next_sibling:
Haavard Skinnemoen9505e632008-07-01 15:14:51 +0200416
417 /*
418 * If "child" isn't empty, walk down the tree and
419 * remove all its descendants first.
420 */
421 if (!list_empty(&child->d_subdirs)) {
422 mutex_unlock(&parent->d_inode->i_mutex);
423 parent = child;
424 mutex_lock(&parent->d_inode->i_mutex);
425 continue;
426 }
427 __debugfs_remove(child, parent);
428 if (parent->d_subdirs.next == &child->d_u.d_child) {
429 /*
Steven Rostedt56a83cc2009-04-25 00:39:40 -0400430 * Try the next sibling.
431 */
432 if (child->d_u.d_child.next != &parent->d_subdirs) {
433 child = list_entry(child->d_u.d_child.next,
434 struct dentry,
435 d_u.d_child);
436 goto next_sibling;
437 }
438
439 /*
Haavard Skinnemoen9505e632008-07-01 15:14:51 +0200440 * Avoid infinite loop if we fail to remove
441 * one dentry.
442 */
443 mutex_unlock(&parent->d_inode->i_mutex);
444 break;
445 }
446 simple_release_fs(&debugfs_mount, &debugfs_mount_count);
447 }
448
449 parent = dentry->d_parent;
450 mutex_lock(&parent->d_inode->i_mutex);
451 __debugfs_remove(dentry, parent);
452 mutex_unlock(&parent->d_inode->i_mutex);
453 simple_release_fs(&debugfs_mount, &debugfs_mount_count);
454}
455EXPORT_SYMBOL_GPL(debugfs_remove_recursive);
456
457/**
Jan Karacfc94cd2007-05-09 13:19:52 +0200458 * debugfs_rename - rename a file/directory in the debugfs filesystem
459 * @old_dir: a pointer to the parent dentry for the renamed object. This
460 * should be a directory dentry.
461 * @old_dentry: dentry of an object to be renamed.
462 * @new_dir: a pointer to the parent dentry where the object should be
463 * moved. This should be a directory dentry.
464 * @new_name: a pointer to a string containing the target name.
465 *
466 * This function renames a file/directory in debugfs. The target must not
467 * exist for rename to succeed.
468 *
469 * This function will return a pointer to old_dentry (which is updated to
470 * reflect renaming) if it succeeds. If an error occurs, %NULL will be
471 * returned.
472 *
473 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
474 * returned.
475 */
476struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry,
477 struct dentry *new_dir, const char *new_name)
478{
479 int error;
480 struct dentry *dentry = NULL, *trap;
481 const char *old_name;
482
483 trap = lock_rename(new_dir, old_dir);
484 /* Source or destination directories don't exist? */
485 if (!old_dir->d_inode || !new_dir->d_inode)
486 goto exit;
487 /* Source does not exist, cyclic rename, or mountpoint? */
488 if (!old_dentry->d_inode || old_dentry == trap ||
489 d_mountpoint(old_dentry))
490 goto exit;
491 dentry = lookup_one_len(new_name, new_dir, strlen(new_name));
492 /* Lookup failed, cyclic rename or target exists? */
493 if (IS_ERR(dentry) || dentry == trap || dentry->d_inode)
494 goto exit;
495
496 old_name = fsnotify_oldname_init(old_dentry->d_name.name);
497
498 error = simple_rename(old_dir->d_inode, old_dentry, new_dir->d_inode,
499 dentry);
500 if (error) {
501 fsnotify_oldname_free(old_name);
502 goto exit;
503 }
504 d_move(old_dentry, dentry);
505 fsnotify_move(old_dir->d_inode, new_dir->d_inode, old_name,
506 old_dentry->d_name.name, S_ISDIR(old_dentry->d_inode->i_mode),
Al Viro5a190ae2007-06-07 12:19:32 -0400507 NULL, old_dentry);
Jan Karacfc94cd2007-05-09 13:19:52 +0200508 fsnotify_oldname_free(old_name);
509 unlock_rename(new_dir, old_dir);
510 dput(dentry);
511 return old_dentry;
512exit:
513 if (dentry && !IS_ERR(dentry))
514 dput(dentry);
515 unlock_rename(new_dir, old_dir);
516 return NULL;
517}
518EXPORT_SYMBOL_GPL(debugfs_rename);
519
Frederic Weisbeckerc0f92ba2009-03-22 23:10:44 +0100520/**
521 * debugfs_initialized - Tells whether debugfs has been registered
522 */
523bool debugfs_initialized(void)
524{
525 return debugfs_registered;
526}
527EXPORT_SYMBOL_GPL(debugfs_initialized);
528
529
Greg Kroah-Hartman191e1862007-10-29 20:13:17 +0100530static struct kobject *debug_kobj;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700531
532static int __init debugfs_init(void)
533{
534 int retval;
535
Greg Kroah-Hartman0ff21e42007-11-06 10:36:58 -0800536 debug_kobj = kobject_create_and_add("debug", kernel_kobj);
Greg Kroah-Hartman191e1862007-10-29 20:13:17 +0100537 if (!debug_kobj)
538 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700539
540 retval = register_filesystem(&debug_fs_type);
541 if (retval)
Greg Kroah-Hartman197b12d2007-12-20 08:13:05 -0800542 kobject_put(debug_kobj);
Frederic Weisbeckerc0f92ba2009-03-22 23:10:44 +0100543 else
544 debugfs_registered = true;
545
Linus Torvalds1da177e2005-04-16 15:20:36 -0700546 return retval;
547}
548
549static void __exit debugfs_exit(void)
550{
Frederic Weisbeckerc0f92ba2009-03-22 23:10:44 +0100551 debugfs_registered = false;
552
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553 simple_release_fs(&debugfs_mount, &debugfs_mount_count);
554 unregister_filesystem(&debug_fs_type);
Greg Kroah-Hartman197b12d2007-12-20 08:13:05 -0800555 kobject_put(debug_kobj);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700556}
557
558core_initcall(debugfs_init);
559module_exit(debugfs_exit);
560MODULE_LICENSE("GPL");
561