1 // SPDX-License-Identifier: GPL-2.0
3 * inode.c - part of debugfs, a tiny little debug file system
5 * Copyright (C) 2004,2019 Greg Kroah-Hartman <greg@kroah.com>
6 * Copyright (C) 2004 IBM Inc.
7 * Copyright (C) 2019 Linux Foundation <gregkh@linuxfoundation.org>
9 * debugfs is for people to use instead of /proc or /sys.
10 * See ./Documentation/core-api/kernel-api.rst for more details.
13 #define pr_fmt(fmt) "debugfs: " fmt
15 #include <linux/module.h>
17 #include <linux/mount.h>
18 #include <linux/pagemap.h>
19 #include <linux/init.h>
20 #include <linux/kobject.h>
21 #include <linux/namei.h>
22 #include <linux/debugfs.h>
23 #include <linux/fsnotify.h>
24 #include <linux/string.h>
25 #include <linux/seq_file.h>
26 #include <linux/parser.h>
27 #include <linux/magic.h>
28 #include <linux/slab.h>
29 #include <linux/security.h>
33 #define DEBUGFS_DEFAULT_MODE 0700
35 static struct vfsmount *debugfs_mount;
36 static int debugfs_mount_count;
37 static bool debugfs_registered;
40 * Don't allow access attributes to be changed whilst the kernel is locked down
41 * so that we can use the file mode as part of a heuristic to determine whether
42 * to lock down individual files.
44 static int debugfs_setattr(struct dentry *dentry, struct iattr *ia)
46 int ret = security_locked_down(LOCKDOWN_DEBUGFS);
48 if (ret && (ia->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID)))
50 return simple_setattr(dentry, ia);
53 static const struct inode_operations debugfs_file_inode_operations = {
54 .setattr = debugfs_setattr,
56 static const struct inode_operations debugfs_dir_inode_operations = {
57 .lookup = simple_lookup,
58 .setattr = debugfs_setattr,
60 static const struct inode_operations debugfs_symlink_inode_operations = {
61 .get_link = simple_get_link,
62 .setattr = debugfs_setattr,
65 static struct inode *debugfs_get_inode(struct super_block *sb)
67 struct inode *inode = new_inode(sb);
69 inode->i_ino = get_next_ino();
70 inode->i_atime = inode->i_mtime =
71 inode->i_ctime = current_time(inode);
76 struct debugfs_mount_opts {
89 static const match_table_t tokens = {
92 {Opt_mode, "mode=%o"},
96 struct debugfs_fs_info {
97 struct debugfs_mount_opts mount_opts;
100 static int debugfs_parse_options(char *data, struct debugfs_mount_opts *opts)
102 substring_t args[MAX_OPT_ARGS];
109 opts->mode = DEBUGFS_DEFAULT_MODE;
111 while ((p = strsep(&data, ",")) != NULL) {
115 token = match_token(p, tokens, args);
118 if (match_int(&args[0], &option))
120 uid = make_kuid(current_user_ns(), option);
126 if (match_int(&args[0], &option))
128 gid = make_kgid(current_user_ns(), option);
134 if (match_octal(&args[0], &option))
136 opts->mode = option & S_IALLUGO;
139 * We might like to report bad mount options here;
140 * but traditionally debugfs has ignored all mount options
148 static int debugfs_apply_options(struct super_block *sb)
150 struct debugfs_fs_info *fsi = sb->s_fs_info;
151 struct inode *inode = d_inode(sb->s_root);
152 struct debugfs_mount_opts *opts = &fsi->mount_opts;
154 inode->i_mode &= ~S_IALLUGO;
155 inode->i_mode |= opts->mode;
157 inode->i_uid = opts->uid;
158 inode->i_gid = opts->gid;
163 static int debugfs_remount(struct super_block *sb, int *flags, char *data)
166 struct debugfs_fs_info *fsi = sb->s_fs_info;
169 err = debugfs_parse_options(data, &fsi->mount_opts);
173 debugfs_apply_options(sb);
179 static int debugfs_show_options(struct seq_file *m, struct dentry *root)
181 struct debugfs_fs_info *fsi = root->d_sb->s_fs_info;
182 struct debugfs_mount_opts *opts = &fsi->mount_opts;
184 if (!uid_eq(opts->uid, GLOBAL_ROOT_UID))
185 seq_printf(m, ",uid=%u",
186 from_kuid_munged(&init_user_ns, opts->uid));
187 if (!gid_eq(opts->gid, GLOBAL_ROOT_GID))
188 seq_printf(m, ",gid=%u",
189 from_kgid_munged(&init_user_ns, opts->gid));
190 if (opts->mode != DEBUGFS_DEFAULT_MODE)
191 seq_printf(m, ",mode=%o", opts->mode);
196 static void debugfs_free_inode(struct inode *inode)
198 if (S_ISLNK(inode->i_mode))
199 kfree(inode->i_link);
200 free_inode_nonrcu(inode);
203 static const struct super_operations debugfs_super_operations = {
204 .statfs = simple_statfs,
205 .remount_fs = debugfs_remount,
206 .show_options = debugfs_show_options,
207 .free_inode = debugfs_free_inode,
210 static void debugfs_release_dentry(struct dentry *dentry)
212 void *fsd = dentry->d_fsdata;
214 if (!((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT))
215 kfree(dentry->d_fsdata);
218 static struct vfsmount *debugfs_automount(struct path *path)
220 debugfs_automount_t f;
221 f = (debugfs_automount_t)path->dentry->d_fsdata;
222 return f(path->dentry, d_inode(path->dentry)->i_private);
225 static const struct dentry_operations debugfs_dops = {
226 .d_delete = always_delete_dentry,
227 .d_release = debugfs_release_dentry,
228 .d_automount = debugfs_automount,
231 static int debug_fill_super(struct super_block *sb, void *data, int silent)
233 static const struct tree_descr debug_files[] = {{""}};
234 struct debugfs_fs_info *fsi;
237 fsi = kzalloc(sizeof(struct debugfs_fs_info), GFP_KERNEL);
244 err = debugfs_parse_options(data, &fsi->mount_opts);
248 err = simple_fill_super(sb, DEBUGFS_MAGIC, debug_files);
252 sb->s_op = &debugfs_super_operations;
253 sb->s_d_op = &debugfs_dops;
255 debugfs_apply_options(sb);
261 sb->s_fs_info = NULL;
265 static struct dentry *debug_mount(struct file_system_type *fs_type,
266 int flags, const char *dev_name,
269 return mount_single(fs_type, flags, data, debug_fill_super);
272 static struct file_system_type debug_fs_type = {
273 .owner = THIS_MODULE,
275 .mount = debug_mount,
276 .kill_sb = kill_litter_super,
278 MODULE_ALIAS_FS("debugfs");
281 * debugfs_lookup() - look up an existing debugfs file
282 * @name: a pointer to a string containing the name of the file to look up.
283 * @parent: a pointer to the parent dentry of the file.
285 * This function will return a pointer to a dentry if it succeeds. If the file
286 * doesn't exist or an error occurs, %NULL will be returned. The returned
287 * dentry must be passed to dput() when it is no longer needed.
289 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
292 struct dentry *debugfs_lookup(const char *name, struct dentry *parent)
294 struct dentry *dentry;
300 parent = debugfs_mount->mnt_root;
302 dentry = lookup_positive_unlocked(name, parent, strlen(name));
307 EXPORT_SYMBOL_GPL(debugfs_lookup);
309 static struct dentry *start_creating(const char *name, struct dentry *parent)
311 struct dentry *dentry;
314 pr_debug("creating file '%s'\n", name);
319 error = simple_pin_fs(&debug_fs_type, &debugfs_mount,
320 &debugfs_mount_count);
322 pr_err("Unable to pin filesystem for file '%s'\n", name);
323 return ERR_PTR(error);
326 /* If the parent is not specified, we create it in the root.
327 * We need the root dentry to do this, which is in the super
328 * block. A pointer to that is in the struct vfsmount that we
332 parent = debugfs_mount->mnt_root;
334 inode_lock(d_inode(parent));
335 dentry = lookup_one_len(name, parent, strlen(name));
336 if (!IS_ERR(dentry) && d_really_is_positive(dentry)) {
337 if (d_is_dir(dentry))
338 pr_err("Directory '%s' with parent '%s' already present!\n",
339 name, parent->d_name.name);
341 pr_err("File '%s' in directory '%s' already present!\n",
342 name, parent->d_name.name);
344 dentry = ERR_PTR(-EEXIST);
347 if (IS_ERR(dentry)) {
348 inode_unlock(d_inode(parent));
349 simple_release_fs(&debugfs_mount, &debugfs_mount_count);
355 static struct dentry *failed_creating(struct dentry *dentry)
357 inode_unlock(d_inode(dentry->d_parent));
359 simple_release_fs(&debugfs_mount, &debugfs_mount_count);
360 return ERR_PTR(-ENOMEM);
363 static struct dentry *end_creating(struct dentry *dentry)
365 inode_unlock(d_inode(dentry->d_parent));
369 static struct dentry *__debugfs_create_file(const char *name, umode_t mode,
370 struct dentry *parent, void *data,
371 const struct file_operations *proxy_fops,
372 const struct file_operations *real_fops)
374 struct dentry *dentry;
377 if (!(mode & S_IFMT))
379 BUG_ON(!S_ISREG(mode));
380 dentry = start_creating(name, parent);
385 inode = debugfs_get_inode(dentry->d_sb);
386 if (unlikely(!inode)) {
387 pr_err("out of free dentries, can not create file '%s'\n",
389 return failed_creating(dentry);
392 inode->i_mode = mode;
393 inode->i_private = data;
395 inode->i_op = &debugfs_file_inode_operations;
396 inode->i_fop = proxy_fops;
397 dentry->d_fsdata = (void *)((unsigned long)real_fops |
398 DEBUGFS_FSDATA_IS_REAL_FOPS_BIT);
400 d_instantiate(dentry, inode);
401 fsnotify_create(d_inode(dentry->d_parent), dentry);
402 return end_creating(dentry);
406 * debugfs_create_file - create a file in the debugfs filesystem
407 * @name: a pointer to a string containing the name of the file to create.
408 * @mode: the permission that the file should have.
409 * @parent: a pointer to the parent dentry for this file. This should be a
410 * directory dentry if set. If this parameter is NULL, then the
411 * file will be created in the root of the debugfs filesystem.
412 * @data: a pointer to something that the caller will want to get to later
413 * on. The inode.i_private pointer will point to this value on
415 * @fops: a pointer to a struct file_operations that should be used for
418 * This is the basic "create a file" function for debugfs. It allows for a
419 * wide range of flexibility in creating a file, or a directory (if you want
420 * to create a directory, the debugfs_create_dir() function is
421 * recommended to be used instead.)
423 * This function will return a pointer to a dentry if it succeeds. This
424 * pointer must be passed to the debugfs_remove() function when the file is
425 * to be removed (no automatic cleanup happens if your module is unloaded,
426 * you are responsible here.) If an error occurs, ERR_PTR(-ERROR) will be
429 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
432 struct dentry *debugfs_create_file(const char *name, umode_t mode,
433 struct dentry *parent, void *data,
434 const struct file_operations *fops)
437 return __debugfs_create_file(name, mode, parent, data,
438 fops ? &debugfs_full_proxy_file_operations :
439 &debugfs_noop_file_operations,
442 EXPORT_SYMBOL_GPL(debugfs_create_file);
445 * debugfs_create_file_unsafe - create a file in the debugfs filesystem
446 * @name: a pointer to a string containing the name of the file to create.
447 * @mode: the permission that the file should have.
448 * @parent: a pointer to the parent dentry for this file. This should be a
449 * directory dentry if set. If this parameter is NULL, then the
450 * file will be created in the root of the debugfs filesystem.
451 * @data: a pointer to something that the caller will want to get to later
452 * on. The inode.i_private pointer will point to this value on
454 * @fops: a pointer to a struct file_operations that should be used for
457 * debugfs_create_file_unsafe() is completely analogous to
458 * debugfs_create_file(), the only difference being that the fops
459 * handed it will not get protected against file removals by the
462 * It is your responsibility to protect your struct file_operation
463 * methods against file removals by means of debugfs_file_get()
464 * and debugfs_file_put(). ->open() is still protected by
467 * Any struct file_operations defined by means of
468 * DEFINE_DEBUGFS_ATTRIBUTE() is protected against file removals and
469 * thus, may be used here.
471 struct dentry *debugfs_create_file_unsafe(const char *name, umode_t mode,
472 struct dentry *parent, void *data,
473 const struct file_operations *fops)
476 return __debugfs_create_file(name, mode, parent, data,
477 fops ? &debugfs_open_proxy_file_operations :
478 &debugfs_noop_file_operations,
481 EXPORT_SYMBOL_GPL(debugfs_create_file_unsafe);
484 * debugfs_create_file_size - create a file in the debugfs filesystem
485 * @name: a pointer to a string containing the name of the file to create.
486 * @mode: the permission that the file should have.
487 * @parent: a pointer to the parent dentry for this file. This should be a
488 * directory dentry if set. If this parameter is NULL, then the
489 * file will be created in the root of the debugfs filesystem.
490 * @data: a pointer to something that the caller will want to get to later
491 * on. The inode.i_private pointer will point to this value on
493 * @fops: a pointer to a struct file_operations that should be used for
495 * @file_size: initial file size
497 * This is the basic "create a file" function for debugfs. It allows for a
498 * wide range of flexibility in creating a file, or a directory (if you want
499 * to create a directory, the debugfs_create_dir() function is
500 * recommended to be used instead.)
502 * This function will return a pointer to a dentry if it succeeds. This
503 * pointer must be passed to the debugfs_remove() function when the file is
504 * to be removed (no automatic cleanup happens if your module is unloaded,
505 * you are responsible here.) If an error occurs, ERR_PTR(-ERROR) will be
508 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
511 struct dentry *debugfs_create_file_size(const char *name, umode_t mode,
512 struct dentry *parent, void *data,
513 const struct file_operations *fops,
516 struct dentry *de = debugfs_create_file(name, mode, parent, data, fops);
519 d_inode(de)->i_size = file_size;
522 EXPORT_SYMBOL_GPL(debugfs_create_file_size);
525 * debugfs_create_dir - create a directory in the debugfs filesystem
526 * @name: a pointer to a string containing the name of the directory to
528 * @parent: a pointer to the parent dentry for this file. This should be a
529 * directory dentry if set. If this parameter is NULL, then the
530 * directory will be created in the root of the debugfs filesystem.
532 * This function creates a directory in debugfs with the given name.
534 * This function will return a pointer to a dentry if it succeeds. This
535 * pointer must be passed to the debugfs_remove() function when the file is
536 * to be removed (no automatic cleanup happens if your module is unloaded,
537 * you are responsible here.) If an error occurs, ERR_PTR(-ERROR) will be
540 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
543 struct dentry *debugfs_create_dir(const char *name, struct dentry *parent)
545 struct dentry *dentry = start_creating(name, parent);
551 inode = debugfs_get_inode(dentry->d_sb);
552 if (unlikely(!inode)) {
553 pr_err("out of free dentries, can not create directory '%s'\n",
555 return failed_creating(dentry);
558 inode->i_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO;
559 inode->i_op = &debugfs_dir_inode_operations;
560 inode->i_fop = &simple_dir_operations;
562 /* directory inodes start off with i_nlink == 2 (for "." entry) */
564 d_instantiate(dentry, inode);
565 inc_nlink(d_inode(dentry->d_parent));
566 fsnotify_mkdir(d_inode(dentry->d_parent), dentry);
567 return end_creating(dentry);
569 EXPORT_SYMBOL_GPL(debugfs_create_dir);
572 * debugfs_create_automount - create automount point in the debugfs filesystem
573 * @name: a pointer to a string containing the name of the file to create.
574 * @parent: a pointer to the parent dentry for this file. This should be a
575 * directory dentry if set. If this parameter is NULL, then the
576 * file will be created in the root of the debugfs filesystem.
577 * @f: function to be called when pathname resolution steps on that one.
578 * @data: opaque argument to pass to f().
580 * @f should return what ->d_automount() would.
582 struct dentry *debugfs_create_automount(const char *name,
583 struct dentry *parent,
584 debugfs_automount_t f,
587 struct dentry *dentry = start_creating(name, parent);
593 inode = debugfs_get_inode(dentry->d_sb);
594 if (unlikely(!inode)) {
595 pr_err("out of free dentries, can not create automount '%s'\n",
597 return failed_creating(dentry);
600 make_empty_dir_inode(inode);
601 inode->i_flags |= S_AUTOMOUNT;
602 inode->i_private = data;
603 dentry->d_fsdata = (void *)f;
604 /* directory inodes start off with i_nlink == 2 (for "." entry) */
606 d_instantiate(dentry, inode);
607 inc_nlink(d_inode(dentry->d_parent));
608 fsnotify_mkdir(d_inode(dentry->d_parent), dentry);
609 return end_creating(dentry);
611 EXPORT_SYMBOL(debugfs_create_automount);
614 * debugfs_create_symlink- create a symbolic link in the debugfs filesystem
615 * @name: a pointer to a string containing the name of the symbolic link to
617 * @parent: a pointer to the parent dentry for this symbolic link. This
618 * should be a directory dentry if set. If this parameter is NULL,
619 * then the symbolic link will be created in the root of the debugfs
621 * @target: a pointer to a string containing the path to the target of the
624 * This function creates a symbolic link with the given name in debugfs that
625 * links to the given target path.
627 * This function will return a pointer to a dentry if it succeeds. This
628 * pointer must be passed to the debugfs_remove() function when the symbolic
629 * link is to be removed (no automatic cleanup happens if your module is
630 * unloaded, you are responsible here.) If an error occurs, ERR_PTR(-ERROR)
633 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
636 struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent,
639 struct dentry *dentry;
641 char *link = kstrdup(target, GFP_KERNEL);
643 return ERR_PTR(-ENOMEM);
645 dentry = start_creating(name, parent);
646 if (IS_ERR(dentry)) {
651 inode = debugfs_get_inode(dentry->d_sb);
652 if (unlikely(!inode)) {
653 pr_err("out of free dentries, can not create symlink '%s'\n",
656 return failed_creating(dentry);
658 inode->i_mode = S_IFLNK | S_IRWXUGO;
659 inode->i_op = &debugfs_symlink_inode_operations;
660 inode->i_link = link;
661 d_instantiate(dentry, inode);
662 return end_creating(dentry);
664 EXPORT_SYMBOL_GPL(debugfs_create_symlink);
666 static void __debugfs_file_removed(struct dentry *dentry)
668 struct debugfs_fsdata *fsd;
671 * Paired with the closing smp_mb() implied by a successful
672 * cmpxchg() in debugfs_file_get(): either
673 * debugfs_file_get() must see a dead dentry or we must see a
674 * debugfs_fsdata instance at ->d_fsdata here (or both).
677 fsd = READ_ONCE(dentry->d_fsdata);
678 if ((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT)
680 if (!refcount_dec_and_test(&fsd->active_users))
681 wait_for_completion(&fsd->active_users_drained);
684 static int __debugfs_remove(struct dentry *dentry, struct dentry *parent)
688 if (simple_positive(dentry)) {
690 if (d_is_dir(dentry)) {
691 ret = simple_rmdir(d_inode(parent), dentry);
693 fsnotify_rmdir(d_inode(parent), dentry);
695 simple_unlink(d_inode(parent), dentry);
696 fsnotify_unlink(d_inode(parent), dentry);
700 if (d_is_reg(dentry))
701 __debugfs_file_removed(dentry);
708 * debugfs_remove - removes a file or directory from the debugfs filesystem
709 * @dentry: a pointer to a the dentry of the file or directory to be
710 * removed. If this parameter is NULL or an error value, nothing
713 * This function removes a file or directory in debugfs that was previously
714 * created with a call to another debugfs function (like
715 * debugfs_create_file() or variants thereof.)
717 * This function is required to be called in order for the file to be
718 * removed, no automatic cleanup of files will happen when a module is
719 * removed, you are responsible here.
721 void debugfs_remove(struct dentry *dentry)
723 struct dentry *parent;
726 if (IS_ERR_OR_NULL(dentry))
729 parent = dentry->d_parent;
730 inode_lock(d_inode(parent));
731 ret = __debugfs_remove(dentry, parent);
732 inode_unlock(d_inode(parent));
734 simple_release_fs(&debugfs_mount, &debugfs_mount_count);
736 EXPORT_SYMBOL_GPL(debugfs_remove);
739 * debugfs_remove_recursive - recursively removes a directory
740 * @dentry: a pointer to a the dentry of the directory to be removed. If this
741 * parameter is NULL or an error value, nothing will be done.
743 * This function recursively removes a directory tree in debugfs that
744 * was previously created with a call to another debugfs function
745 * (like debugfs_create_file() or variants thereof.)
747 * This function is required to be called in order for the file to be
748 * removed, no automatic cleanup of files will happen when a module is
749 * removed, you are responsible here.
751 void debugfs_remove_recursive(struct dentry *dentry)
753 struct dentry *child, *parent;
755 if (IS_ERR_OR_NULL(dentry))
760 inode_lock(d_inode(parent));
763 * The parent->d_subdirs is protected by the d_lock. Outside that
764 * lock, the child can be unlinked and set to be freed which can
765 * use the d_u.d_child as the rcu head and corrupt this list.
767 spin_lock(&parent->d_lock);
768 list_for_each_entry(child, &parent->d_subdirs, d_child) {
769 if (!simple_positive(child))
772 /* perhaps simple_empty(child) makes more sense */
773 if (!list_empty(&child->d_subdirs)) {
774 spin_unlock(&parent->d_lock);
775 inode_unlock(d_inode(parent));
780 spin_unlock(&parent->d_lock);
782 if (!__debugfs_remove(child, parent))
783 simple_release_fs(&debugfs_mount, &debugfs_mount_count);
786 * The parent->d_lock protects agaist child from unlinking
787 * from d_subdirs. When releasing the parent->d_lock we can
788 * no longer trust that the next pointer is valid.
789 * Restart the loop. We'll skip this one with the
790 * simple_positive() check.
794 spin_unlock(&parent->d_lock);
796 inode_unlock(d_inode(parent));
798 parent = parent->d_parent;
799 inode_lock(d_inode(parent));
805 if (!__debugfs_remove(child, parent))
806 simple_release_fs(&debugfs_mount, &debugfs_mount_count);
807 inode_unlock(d_inode(parent));
809 EXPORT_SYMBOL_GPL(debugfs_remove_recursive);
812 * debugfs_rename - rename a file/directory in the debugfs filesystem
813 * @old_dir: a pointer to the parent dentry for the renamed object. This
814 * should be a directory dentry.
815 * @old_dentry: dentry of an object to be renamed.
816 * @new_dir: a pointer to the parent dentry where the object should be
817 * moved. This should be a directory dentry.
818 * @new_name: a pointer to a string containing the target name.
820 * This function renames a file/directory in debugfs. The target must not
821 * exist for rename to succeed.
823 * This function will return a pointer to old_dentry (which is updated to
824 * reflect renaming) if it succeeds. If an error occurs, %NULL will be
827 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
830 struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry,
831 struct dentry *new_dir, const char *new_name)
834 struct dentry *dentry = NULL, *trap;
835 struct name_snapshot old_name;
841 if (IS_ERR_OR_NULL(old_dentry))
844 trap = lock_rename(new_dir, old_dir);
845 /* Source or destination directories don't exist? */
846 if (d_really_is_negative(old_dir) || d_really_is_negative(new_dir))
848 /* Source does not exist, cyclic rename, or mountpoint? */
849 if (d_really_is_negative(old_dentry) || old_dentry == trap ||
850 d_mountpoint(old_dentry))
852 dentry = lookup_one_len(new_name, new_dir, strlen(new_name));
853 /* Lookup failed, cyclic rename or target exists? */
854 if (IS_ERR(dentry) || dentry == trap || d_really_is_positive(dentry))
857 take_dentry_name_snapshot(&old_name, old_dentry);
859 error = simple_rename(d_inode(old_dir), old_dentry, d_inode(new_dir),
862 release_dentry_name_snapshot(&old_name);
865 d_move(old_dentry, dentry);
866 fsnotify_move(d_inode(old_dir), d_inode(new_dir), &old_name.name,
867 d_is_dir(old_dentry),
869 release_dentry_name_snapshot(&old_name);
870 unlock_rename(new_dir, old_dir);
874 if (dentry && !IS_ERR(dentry))
876 unlock_rename(new_dir, old_dir);
879 return ERR_PTR(-EINVAL);
881 EXPORT_SYMBOL_GPL(debugfs_rename);
884 * debugfs_initialized - Tells whether debugfs has been registered
886 bool debugfs_initialized(void)
888 return debugfs_registered;
890 EXPORT_SYMBOL_GPL(debugfs_initialized);
892 static int __init debugfs_init(void)
896 retval = sysfs_create_mount_point(kernel_kobj, "debug");
900 retval = register_filesystem(&debug_fs_type);
902 sysfs_remove_mount_point(kernel_kobj, "debug");
904 debugfs_registered = true;
908 core_initcall(debugfs_init);