Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ryusuke...
[linux-2.6/mini2440.git] / fs / debugfs / inode.c
blobd22438ef7674870ad4987b9c2eb11555057e4dc8
1 /*
2 * file.c - part of debugfs, a tiny little debug file system
4 * Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com>
5 * Copyright (C) 2004 IBM Inc.
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.
11 * debugfs is for people to use instead of /proc or /sys.
12 * See Documentation/DocBook/kernel-api for more details.
16 /* uncomment to get debug messages from the debug filesystem, ah the irony. */
17 /* #define DEBUG */
19 #include <linux/module.h>
20 #include <linux/fs.h>
21 #include <linux/mount.h>
22 #include <linux/pagemap.h>
23 #include <linux/init.h>
24 #include <linux/kobject.h>
25 #include <linux/namei.h>
26 #include <linux/debugfs.h>
27 #include <linux/fsnotify.h>
28 #include <linux/string.h>
29 #include <linux/magic.h>
31 static struct vfsmount *debugfs_mount;
32 static int debugfs_mount_count;
33 static bool debugfs_registered;
35 static struct inode *debugfs_get_inode(struct super_block *sb, int mode, dev_t dev)
37 struct inode *inode = new_inode(sb);
39 if (inode) {
40 inode->i_mode = mode;
41 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
42 switch (mode & S_IFMT) {
43 default:
44 init_special_inode(inode, mode, dev);
45 break;
46 case S_IFREG:
47 inode->i_fop = &debugfs_file_operations;
48 break;
49 case S_IFLNK:
50 inode->i_op = &debugfs_link_operations;
51 break;
52 case S_IFDIR:
53 inode->i_op = &simple_dir_inode_operations;
54 inode->i_fop = &simple_dir_operations;
56 /* directory inodes start off with i_nlink == 2
57 * (for "." entry) */
58 inc_nlink(inode);
59 break;
62 return inode;
65 /* SMP-safe */
66 static int debugfs_mknod(struct inode *dir, struct dentry *dentry,
67 int mode, dev_t dev)
69 struct inode *inode;
70 int error = -EPERM;
72 if (dentry->d_inode)
73 return -EEXIST;
75 inode = debugfs_get_inode(dir->i_sb, mode, dev);
76 if (inode) {
77 d_instantiate(dentry, inode);
78 dget(dentry);
79 error = 0;
81 return error;
84 static int debugfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
86 int res;
88 mode = (mode & (S_IRWXUGO | S_ISVTX)) | S_IFDIR;
89 res = debugfs_mknod(dir, dentry, mode, 0);
90 if (!res) {
91 inc_nlink(dir);
92 fsnotify_mkdir(dir, dentry);
94 return res;
97 static int debugfs_link(struct inode *dir, struct dentry *dentry, int mode)
99 mode = (mode & S_IALLUGO) | S_IFLNK;
100 return debugfs_mknod(dir, dentry, mode, 0);
103 static int debugfs_create(struct inode *dir, struct dentry *dentry, int mode)
105 int res;
107 mode = (mode & S_IALLUGO) | S_IFREG;
108 res = debugfs_mknod(dir, dentry, mode, 0);
109 if (!res)
110 fsnotify_create(dir, dentry);
111 return res;
114 static inline int debugfs_positive(struct dentry *dentry)
116 return dentry->d_inode && !d_unhashed(dentry);
119 static int debug_fill_super(struct super_block *sb, void *data, int silent)
121 static struct tree_descr debug_files[] = {{""}};
123 return simple_fill_super(sb, DEBUGFS_MAGIC, debug_files);
126 static int debug_get_sb(struct file_system_type *fs_type,
127 int flags, const char *dev_name,
128 void *data, struct vfsmount *mnt)
130 return get_sb_single(fs_type, flags, data, debug_fill_super, mnt);
133 static struct file_system_type debug_fs_type = {
134 .owner = THIS_MODULE,
135 .name = "debugfs",
136 .get_sb = debug_get_sb,
137 .kill_sb = kill_litter_super,
140 static int debugfs_create_by_name(const char *name, mode_t mode,
141 struct dentry *parent,
142 struct dentry **dentry)
144 int error = 0;
146 /* If the parent is not specified, we create it in the root.
147 * We need the root dentry to do this, which is in the super
148 * block. A pointer to that is in the struct vfsmount that we
149 * have around.
151 if (!parent) {
152 if (debugfs_mount && debugfs_mount->mnt_sb) {
153 parent = debugfs_mount->mnt_sb->s_root;
156 if (!parent) {
157 pr_debug("debugfs: Ah! can not find a parent!\n");
158 return -EFAULT;
161 *dentry = NULL;
162 mutex_lock(&parent->d_inode->i_mutex);
163 *dentry = lookup_one_len(name, parent, strlen(name));
164 if (!IS_ERR(*dentry)) {
165 switch (mode & S_IFMT) {
166 case S_IFDIR:
167 error = debugfs_mkdir(parent->d_inode, *dentry, mode);
168 break;
169 case S_IFLNK:
170 error = debugfs_link(parent->d_inode, *dentry, mode);
171 break;
172 default:
173 error = debugfs_create(parent->d_inode, *dentry, mode);
174 break;
176 dput(*dentry);
177 } else
178 error = PTR_ERR(*dentry);
179 mutex_unlock(&parent->d_inode->i_mutex);
181 return error;
185 * debugfs_create_file - create a file in the debugfs filesystem
186 * @name: a pointer to a string containing the name of the file to create.
187 * @mode: the permission that the file should have
188 * @parent: a pointer to the parent dentry for this file. This should be a
189 * directory dentry if set. If this paramater is NULL, then the
190 * file will be created in the root of the debugfs filesystem.
191 * @data: a pointer to something that the caller will want to get to later
192 * on. The inode.i_private pointer will point to this value on
193 * the open() call.
194 * @fops: a pointer to a struct file_operations that should be used for
195 * this file.
197 * This is the basic "create a file" function for debugfs. It allows for a
198 * wide range of flexibility in createing a file, or a directory (if you
199 * want to create a directory, the debugfs_create_dir() function is
200 * recommended to be used instead.)
202 * This function will return a pointer to a dentry if it succeeds. This
203 * pointer must be passed to the debugfs_remove() function when the file is
204 * to be removed (no automatic cleanup happens if your module is unloaded,
205 * you are responsible here.) If an error occurs, %NULL will be returned.
207 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
208 * returned.
210 struct dentry *debugfs_create_file(const char *name, mode_t mode,
211 struct dentry *parent, void *data,
212 const struct file_operations *fops)
214 struct dentry *dentry = NULL;
215 int error;
217 pr_debug("debugfs: creating file '%s'\n",name);
219 error = simple_pin_fs(&debug_fs_type, &debugfs_mount,
220 &debugfs_mount_count);
221 if (error)
222 goto exit;
224 error = debugfs_create_by_name(name, mode, parent, &dentry);
225 if (error) {
226 dentry = NULL;
227 simple_release_fs(&debugfs_mount, &debugfs_mount_count);
228 goto exit;
231 if (dentry->d_inode) {
232 if (data)
233 dentry->d_inode->i_private = data;
234 if (fops)
235 dentry->d_inode->i_fop = fops;
237 exit:
238 return dentry;
240 EXPORT_SYMBOL_GPL(debugfs_create_file);
243 * debugfs_create_dir - create a directory in the debugfs filesystem
244 * @name: a pointer to a string containing the name of the directory to
245 * create.
246 * @parent: a pointer to the parent dentry for this file. This should be a
247 * directory dentry if set. If this paramater is NULL, then the
248 * directory will be created in the root of the debugfs filesystem.
250 * This function creates a directory in debugfs with the given name.
252 * This function will return a pointer to a dentry if it succeeds. This
253 * pointer must be passed to the debugfs_remove() function when the file is
254 * to be removed (no automatic cleanup happens if your module is unloaded,
255 * you are responsible here.) If an error occurs, %NULL will be returned.
257 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
258 * returned.
260 struct dentry *debugfs_create_dir(const char *name, struct dentry *parent)
262 return debugfs_create_file(name,
263 S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
264 parent, NULL, NULL);
266 EXPORT_SYMBOL_GPL(debugfs_create_dir);
269 * debugfs_create_symlink- create a symbolic link in the debugfs filesystem
270 * @name: a pointer to a string containing the name of the symbolic link to
271 * create.
272 * @parent: a pointer to the parent dentry for this symbolic link. This
273 * should be a directory dentry if set. If this paramater is NULL,
274 * then the symbolic link will be created in the root of the debugfs
275 * filesystem.
276 * @target: a pointer to a string containing the path to the target of the
277 * symbolic link.
279 * This function creates a symbolic link with the given name in debugfs that
280 * links to the given target path.
282 * This function will return a pointer to a dentry if it succeeds. This
283 * pointer must be passed to the debugfs_remove() function when the symbolic
284 * link is to be removed (no automatic cleanup happens if your module is
285 * unloaded, you are responsible here.) If an error occurs, %NULL will be
286 * returned.
288 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
289 * returned.
291 struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent,
292 const char *target)
294 struct dentry *result;
295 char *link;
297 link = kstrdup(target, GFP_KERNEL);
298 if (!link)
299 return NULL;
301 result = debugfs_create_file(name, S_IFLNK | S_IRWXUGO, parent, link,
302 NULL);
303 if (!result)
304 kfree(link);
305 return result;
307 EXPORT_SYMBOL_GPL(debugfs_create_symlink);
309 static void __debugfs_remove(struct dentry *dentry, struct dentry *parent)
311 int ret = 0;
313 if (debugfs_positive(dentry)) {
314 if (dentry->d_inode) {
315 dget(dentry);
316 switch (dentry->d_inode->i_mode & S_IFMT) {
317 case S_IFDIR:
318 ret = simple_rmdir(parent->d_inode, dentry);
319 break;
320 case S_IFLNK:
321 kfree(dentry->d_inode->i_private);
322 /* fall through */
323 default:
324 simple_unlink(parent->d_inode, dentry);
325 break;
327 if (!ret)
328 d_delete(dentry);
329 dput(dentry);
335 * debugfs_remove - removes a file or directory from the debugfs filesystem
336 * @dentry: a pointer to a the dentry of the file or directory to be
337 * removed.
339 * This function removes a file or directory in debugfs that was previously
340 * created with a call to another debugfs function (like
341 * debugfs_create_file() or variants thereof.)
343 * This function is required to be called in order for the file to be
344 * removed, no automatic cleanup of files will happen when a module is
345 * removed, you are responsible here.
347 void debugfs_remove(struct dentry *dentry)
349 struct dentry *parent;
351 if (!dentry)
352 return;
354 parent = dentry->d_parent;
355 if (!parent || !parent->d_inode)
356 return;
358 mutex_lock(&parent->d_inode->i_mutex);
359 __debugfs_remove(dentry, parent);
360 mutex_unlock(&parent->d_inode->i_mutex);
361 simple_release_fs(&debugfs_mount, &debugfs_mount_count);
363 EXPORT_SYMBOL_GPL(debugfs_remove);
366 * debugfs_remove_recursive - recursively removes a directory
367 * @dentry: a pointer to a the dentry of the directory to be removed.
369 * This function recursively removes a directory tree in debugfs that
370 * was previously created with a call to another debugfs function
371 * (like debugfs_create_file() or variants thereof.)
373 * This function is required to be called in order for the file to be
374 * removed, no automatic cleanup of files will happen when a module is
375 * removed, you are responsible here.
377 void debugfs_remove_recursive(struct dentry *dentry)
379 struct dentry *child;
380 struct dentry *parent;
382 if (!dentry)
383 return;
385 parent = dentry->d_parent;
386 if (!parent || !parent->d_inode)
387 return;
389 parent = dentry;
390 mutex_lock(&parent->d_inode->i_mutex);
392 while (1) {
394 * When all dentries under "parent" has been removed,
395 * walk up the tree until we reach our starting point.
397 if (list_empty(&parent->d_subdirs)) {
398 mutex_unlock(&parent->d_inode->i_mutex);
399 if (parent == dentry)
400 break;
401 parent = parent->d_parent;
402 mutex_lock(&parent->d_inode->i_mutex);
404 child = list_entry(parent->d_subdirs.next, struct dentry,
405 d_u.d_child);
406 next_sibling:
409 * If "child" isn't empty, walk down the tree and
410 * remove all its descendants first.
412 if (!list_empty(&child->d_subdirs)) {
413 mutex_unlock(&parent->d_inode->i_mutex);
414 parent = child;
415 mutex_lock(&parent->d_inode->i_mutex);
416 continue;
418 __debugfs_remove(child, parent);
419 if (parent->d_subdirs.next == &child->d_u.d_child) {
421 * Try the next sibling.
423 if (child->d_u.d_child.next != &parent->d_subdirs) {
424 child = list_entry(child->d_u.d_child.next,
425 struct dentry,
426 d_u.d_child);
427 goto next_sibling;
431 * Avoid infinite loop if we fail to remove
432 * one dentry.
434 mutex_unlock(&parent->d_inode->i_mutex);
435 break;
437 simple_release_fs(&debugfs_mount, &debugfs_mount_count);
440 parent = dentry->d_parent;
441 mutex_lock(&parent->d_inode->i_mutex);
442 __debugfs_remove(dentry, parent);
443 mutex_unlock(&parent->d_inode->i_mutex);
444 simple_release_fs(&debugfs_mount, &debugfs_mount_count);
446 EXPORT_SYMBOL_GPL(debugfs_remove_recursive);
449 * debugfs_rename - rename a file/directory in the debugfs filesystem
450 * @old_dir: a pointer to the parent dentry for the renamed object. This
451 * should be a directory dentry.
452 * @old_dentry: dentry of an object to be renamed.
453 * @new_dir: a pointer to the parent dentry where the object should be
454 * moved. This should be a directory dentry.
455 * @new_name: a pointer to a string containing the target name.
457 * This function renames a file/directory in debugfs. The target must not
458 * exist for rename to succeed.
460 * This function will return a pointer to old_dentry (which is updated to
461 * reflect renaming) if it succeeds. If an error occurs, %NULL will be
462 * returned.
464 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
465 * returned.
467 struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry,
468 struct dentry *new_dir, const char *new_name)
470 int error;
471 struct dentry *dentry = NULL, *trap;
472 const char *old_name;
474 trap = lock_rename(new_dir, old_dir);
475 /* Source or destination directories don't exist? */
476 if (!old_dir->d_inode || !new_dir->d_inode)
477 goto exit;
478 /* Source does not exist, cyclic rename, or mountpoint? */
479 if (!old_dentry->d_inode || old_dentry == trap ||
480 d_mountpoint(old_dentry))
481 goto exit;
482 dentry = lookup_one_len(new_name, new_dir, strlen(new_name));
483 /* Lookup failed, cyclic rename or target exists? */
484 if (IS_ERR(dentry) || dentry == trap || dentry->d_inode)
485 goto exit;
487 old_name = fsnotify_oldname_init(old_dentry->d_name.name);
489 error = simple_rename(old_dir->d_inode, old_dentry, new_dir->d_inode,
490 dentry);
491 if (error) {
492 fsnotify_oldname_free(old_name);
493 goto exit;
495 d_move(old_dentry, dentry);
496 fsnotify_move(old_dir->d_inode, new_dir->d_inode, old_name,
497 old_dentry->d_name.name, S_ISDIR(old_dentry->d_inode->i_mode),
498 NULL, old_dentry);
499 fsnotify_oldname_free(old_name);
500 unlock_rename(new_dir, old_dir);
501 dput(dentry);
502 return old_dentry;
503 exit:
504 if (dentry && !IS_ERR(dentry))
505 dput(dentry);
506 unlock_rename(new_dir, old_dir);
507 return NULL;
509 EXPORT_SYMBOL_GPL(debugfs_rename);
512 * debugfs_initialized - Tells whether debugfs has been registered
514 bool debugfs_initialized(void)
516 return debugfs_registered;
518 EXPORT_SYMBOL_GPL(debugfs_initialized);
521 static struct kobject *debug_kobj;
523 static int __init debugfs_init(void)
525 int retval;
527 debug_kobj = kobject_create_and_add("debug", kernel_kobj);
528 if (!debug_kobj)
529 return -EINVAL;
531 retval = register_filesystem(&debug_fs_type);
532 if (retval)
533 kobject_put(debug_kobj);
534 else
535 debugfs_registered = true;
537 return retval;
540 static void __exit debugfs_exit(void)
542 debugfs_registered = false;
544 simple_release_fs(&debugfs_mount, &debugfs_mount_count);
545 unregister_filesystem(&debug_fs_type);
546 kobject_put(debug_kobj);
549 core_initcall(debugfs_init);
550 module_exit(debugfs_exit);
551 MODULE_LICENSE("GPL");