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
;
38 static unsigned int debugfs_allow __ro_after_init
= DEFAULT_DEBUGFS_ALLOW_BITS
;
41 * Don't allow access attributes to be changed whilst the kernel is locked down
42 * so that we can use the file mode as part of a heuristic to determine whether
43 * to lock down individual files.
45 static int debugfs_setattr(struct mnt_idmap
*idmap
,
46 struct dentry
*dentry
, struct iattr
*ia
)
50 if (ia
->ia_valid
& (ATTR_MODE
| ATTR_UID
| ATTR_GID
)) {
51 ret
= security_locked_down(LOCKDOWN_DEBUGFS
);
55 return simple_setattr(&nop_mnt_idmap
, dentry
, ia
);
58 static const struct inode_operations debugfs_file_inode_operations
= {
59 .setattr
= debugfs_setattr
,
61 static const struct inode_operations debugfs_dir_inode_operations
= {
62 .lookup
= simple_lookup
,
63 .setattr
= debugfs_setattr
,
65 static const struct inode_operations debugfs_symlink_inode_operations
= {
66 .get_link
= simple_get_link
,
67 .setattr
= debugfs_setattr
,
70 static struct inode
*debugfs_get_inode(struct super_block
*sb
)
72 struct inode
*inode
= new_inode(sb
);
74 inode
->i_ino
= get_next_ino();
75 simple_inode_init_ts(inode
);
80 struct debugfs_mount_opts
{
95 static const match_table_t tokens
= {
98 {Opt_mode
, "mode=%o"},
102 struct debugfs_fs_info
{
103 struct debugfs_mount_opts mount_opts
;
106 static int debugfs_parse_options(char *data
, struct debugfs_mount_opts
*opts
)
108 substring_t args
[MAX_OPT_ARGS
];
116 opts
->mode
= DEBUGFS_DEFAULT_MODE
;
118 while ((p
= strsep(&data
, ",")) != NULL
) {
122 token
= match_token(p
, tokens
, args
);
125 if (match_int(&args
[0], &option
))
127 uid
= make_kuid(current_user_ns(), option
);
133 if (match_int(&args
[0], &option
))
135 gid
= make_kgid(current_user_ns(), option
);
141 if (match_octal(&args
[0], &option
))
143 opts
->mode
= option
& S_IALLUGO
;
146 * We might like to report bad mount options here;
147 * but traditionally debugfs has ignored all mount options
151 opts
->opts
|= BIT(token
);
157 static void _debugfs_apply_options(struct super_block
*sb
, bool remount
)
159 struct debugfs_fs_info
*fsi
= sb
->s_fs_info
;
160 struct inode
*inode
= d_inode(sb
->s_root
);
161 struct debugfs_mount_opts
*opts
= &fsi
->mount_opts
;
164 * On remount, only reset mode/uid/gid if they were provided as mount
168 if (!remount
|| opts
->opts
& BIT(Opt_mode
)) {
169 inode
->i_mode
&= ~S_IALLUGO
;
170 inode
->i_mode
|= opts
->mode
;
173 if (!remount
|| opts
->opts
& BIT(Opt_uid
))
174 inode
->i_uid
= opts
->uid
;
176 if (!remount
|| opts
->opts
& BIT(Opt_gid
))
177 inode
->i_gid
= opts
->gid
;
180 static void debugfs_apply_options(struct super_block
*sb
)
182 _debugfs_apply_options(sb
, false);
185 static void debugfs_apply_options_remount(struct super_block
*sb
)
187 _debugfs_apply_options(sb
, true);
190 static int debugfs_remount(struct super_block
*sb
, int *flags
, char *data
)
193 struct debugfs_fs_info
*fsi
= sb
->s_fs_info
;
196 err
= debugfs_parse_options(data
, &fsi
->mount_opts
);
200 debugfs_apply_options_remount(sb
);
206 static int debugfs_show_options(struct seq_file
*m
, struct dentry
*root
)
208 struct debugfs_fs_info
*fsi
= root
->d_sb
->s_fs_info
;
209 struct debugfs_mount_opts
*opts
= &fsi
->mount_opts
;
211 if (!uid_eq(opts
->uid
, GLOBAL_ROOT_UID
))
212 seq_printf(m
, ",uid=%u",
213 from_kuid_munged(&init_user_ns
, opts
->uid
));
214 if (!gid_eq(opts
->gid
, GLOBAL_ROOT_GID
))
215 seq_printf(m
, ",gid=%u",
216 from_kgid_munged(&init_user_ns
, opts
->gid
));
217 if (opts
->mode
!= DEBUGFS_DEFAULT_MODE
)
218 seq_printf(m
, ",mode=%o", opts
->mode
);
223 static void debugfs_free_inode(struct inode
*inode
)
225 if (S_ISLNK(inode
->i_mode
))
226 kfree(inode
->i_link
);
227 free_inode_nonrcu(inode
);
230 static const struct super_operations debugfs_super_operations
= {
231 .statfs
= simple_statfs
,
232 .remount_fs
= debugfs_remount
,
233 .show_options
= debugfs_show_options
,
234 .free_inode
= debugfs_free_inode
,
237 static void debugfs_release_dentry(struct dentry
*dentry
)
239 struct debugfs_fsdata
*fsd
= dentry
->d_fsdata
;
241 if ((unsigned long)fsd
& DEBUGFS_FSDATA_IS_REAL_FOPS_BIT
)
244 /* check it wasn't a dir (no fsdata) or automount (no real_fops) */
245 if (fsd
&& fsd
->real_fops
) {
246 #ifdef CONFIG_LOCKDEP
247 lockdep_unregister_key(&fsd
->key
);
248 kfree(fsd
->lock_name
);
250 WARN_ON(!list_empty(&fsd
->cancellations
));
251 mutex_destroy(&fsd
->cancellations_mtx
);
257 static struct vfsmount
*debugfs_automount(struct path
*path
)
259 struct debugfs_fsdata
*fsd
= path
->dentry
->d_fsdata
;
261 return fsd
->automount(path
->dentry
, d_inode(path
->dentry
)->i_private
);
264 static const struct dentry_operations debugfs_dops
= {
265 .d_delete
= always_delete_dentry
,
266 .d_release
= debugfs_release_dentry
,
267 .d_automount
= debugfs_automount
,
270 static int debug_fill_super(struct super_block
*sb
, void *data
, int silent
)
272 static const struct tree_descr debug_files
[] = {{""}};
273 struct debugfs_fs_info
*fsi
;
276 fsi
= kzalloc(sizeof(struct debugfs_fs_info
), GFP_KERNEL
);
283 err
= debugfs_parse_options(data
, &fsi
->mount_opts
);
287 err
= simple_fill_super(sb
, DEBUGFS_MAGIC
, debug_files
);
291 sb
->s_op
= &debugfs_super_operations
;
292 sb
->s_d_op
= &debugfs_dops
;
294 debugfs_apply_options(sb
);
300 sb
->s_fs_info
= NULL
;
304 static struct dentry
*debug_mount(struct file_system_type
*fs_type
,
305 int flags
, const char *dev_name
,
308 if (!(debugfs_allow
& DEBUGFS_ALLOW_API
))
309 return ERR_PTR(-EPERM
);
311 return mount_single(fs_type
, flags
, data
, debug_fill_super
);
314 static struct file_system_type debug_fs_type
= {
315 .owner
= THIS_MODULE
,
317 .mount
= debug_mount
,
318 .kill_sb
= kill_litter_super
,
320 MODULE_ALIAS_FS("debugfs");
323 * debugfs_lookup() - look up an existing debugfs file
324 * @name: a pointer to a string containing the name of the file to look up.
325 * @parent: a pointer to the parent dentry of the file.
327 * This function will return a pointer to a dentry if it succeeds. If the file
328 * doesn't exist or an error occurs, %NULL will be returned. The returned
329 * dentry must be passed to dput() when it is no longer needed.
331 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
334 struct dentry
*debugfs_lookup(const char *name
, struct dentry
*parent
)
336 struct dentry
*dentry
;
338 if (!debugfs_initialized() || IS_ERR_OR_NULL(name
) || IS_ERR(parent
))
342 parent
= debugfs_mount
->mnt_root
;
344 dentry
= lookup_positive_unlocked(name
, parent
, strlen(name
));
349 EXPORT_SYMBOL_GPL(debugfs_lookup
);
351 static struct dentry
*start_creating(const char *name
, struct dentry
*parent
)
353 struct dentry
*dentry
;
356 if (!(debugfs_allow
& DEBUGFS_ALLOW_API
))
357 return ERR_PTR(-EPERM
);
359 if (!debugfs_initialized())
360 return ERR_PTR(-ENOENT
);
362 pr_debug("creating file '%s'\n", name
);
367 error
= simple_pin_fs(&debug_fs_type
, &debugfs_mount
,
368 &debugfs_mount_count
);
370 pr_err("Unable to pin filesystem for file '%s'\n", name
);
371 return ERR_PTR(error
);
374 /* If the parent is not specified, we create it in the root.
375 * We need the root dentry to do this, which is in the super
376 * block. A pointer to that is in the struct vfsmount that we
380 parent
= debugfs_mount
->mnt_root
;
382 inode_lock(d_inode(parent
));
383 if (unlikely(IS_DEADDIR(d_inode(parent
))))
384 dentry
= ERR_PTR(-ENOENT
);
386 dentry
= lookup_one_len(name
, parent
, strlen(name
));
387 if (!IS_ERR(dentry
) && d_really_is_positive(dentry
)) {
388 if (d_is_dir(dentry
))
389 pr_err("Directory '%s' with parent '%s' already present!\n",
390 name
, parent
->d_name
.name
);
392 pr_err("File '%s' in directory '%s' already present!\n",
393 name
, parent
->d_name
.name
);
395 dentry
= ERR_PTR(-EEXIST
);
398 if (IS_ERR(dentry
)) {
399 inode_unlock(d_inode(parent
));
400 simple_release_fs(&debugfs_mount
, &debugfs_mount_count
);
406 static struct dentry
*failed_creating(struct dentry
*dentry
)
408 inode_unlock(d_inode(dentry
->d_parent
));
410 simple_release_fs(&debugfs_mount
, &debugfs_mount_count
);
411 return ERR_PTR(-ENOMEM
);
414 static struct dentry
*end_creating(struct dentry
*dentry
)
416 inode_unlock(d_inode(dentry
->d_parent
));
420 static struct dentry
*__debugfs_create_file(const char *name
, umode_t mode
,
421 struct dentry
*parent
, void *data
,
422 const struct file_operations
*proxy_fops
,
423 const struct file_operations
*real_fops
)
425 struct dentry
*dentry
;
428 if (!(mode
& S_IFMT
))
430 BUG_ON(!S_ISREG(mode
));
431 dentry
= start_creating(name
, parent
);
436 if (!(debugfs_allow
& DEBUGFS_ALLOW_API
)) {
437 failed_creating(dentry
);
438 return ERR_PTR(-EPERM
);
441 inode
= debugfs_get_inode(dentry
->d_sb
);
442 if (unlikely(!inode
)) {
443 pr_err("out of free dentries, can not create file '%s'\n",
445 return failed_creating(dentry
);
448 inode
->i_mode
= mode
;
449 inode
->i_private
= data
;
451 inode
->i_op
= &debugfs_file_inode_operations
;
452 inode
->i_fop
= proxy_fops
;
453 dentry
->d_fsdata
= (void *)((unsigned long)real_fops
|
454 DEBUGFS_FSDATA_IS_REAL_FOPS_BIT
);
456 d_instantiate(dentry
, inode
);
457 fsnotify_create(d_inode(dentry
->d_parent
), dentry
);
458 return end_creating(dentry
);
462 * debugfs_create_file - create a file in the debugfs filesystem
463 * @name: a pointer to a string containing the name of the file to create.
464 * @mode: the permission that the file should have.
465 * @parent: a pointer to the parent dentry for this file. This should be a
466 * directory dentry if set. If this parameter is NULL, then the
467 * file will be created in the root of the debugfs filesystem.
468 * @data: a pointer to something that the caller will want to get to later
469 * on. The inode.i_private pointer will point to this value on
471 * @fops: a pointer to a struct file_operations that should be used for
474 * This is the basic "create a file" function for debugfs. It allows for a
475 * wide range of flexibility in creating a file, or a directory (if you want
476 * to create a directory, the debugfs_create_dir() function is
477 * recommended to be used instead.)
479 * This function will return a pointer to a dentry if it succeeds. This
480 * pointer must be passed to the debugfs_remove() function when the file is
481 * to be removed (no automatic cleanup happens if your module is unloaded,
482 * you are responsible here.) If an error occurs, ERR_PTR(-ERROR) will be
485 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
488 * NOTE: it's expected that most callers should _ignore_ the errors returned
489 * by this function. Other debugfs functions handle the fact that the "dentry"
490 * passed to them could be an error and they don't crash in that case.
491 * Drivers should generally work fine even if debugfs fails to init anyway.
493 struct dentry
*debugfs_create_file(const char *name
, umode_t mode
,
494 struct dentry
*parent
, void *data
,
495 const struct file_operations
*fops
)
498 return __debugfs_create_file(name
, mode
, parent
, data
,
499 fops
? &debugfs_full_proxy_file_operations
:
500 &debugfs_noop_file_operations
,
503 EXPORT_SYMBOL_GPL(debugfs_create_file
);
506 * debugfs_create_file_unsafe - create a file in the debugfs filesystem
507 * @name: a pointer to a string containing the name of the file to create.
508 * @mode: the permission that the file should have.
509 * @parent: a pointer to the parent dentry for this file. This should be a
510 * directory dentry if set. If this parameter is NULL, then the
511 * file will be created in the root of the debugfs filesystem.
512 * @data: a pointer to something that the caller will want to get to later
513 * on. The inode.i_private pointer will point to this value on
515 * @fops: a pointer to a struct file_operations that should be used for
518 * debugfs_create_file_unsafe() is completely analogous to
519 * debugfs_create_file(), the only difference being that the fops
520 * handed it will not get protected against file removals by the
523 * It is your responsibility to protect your struct file_operation
524 * methods against file removals by means of debugfs_file_get()
525 * and debugfs_file_put(). ->open() is still protected by
528 * Any struct file_operations defined by means of
529 * DEFINE_DEBUGFS_ATTRIBUTE() is protected against file removals and
530 * thus, may be used here.
532 struct dentry
*debugfs_create_file_unsafe(const char *name
, umode_t mode
,
533 struct dentry
*parent
, void *data
,
534 const struct file_operations
*fops
)
537 return __debugfs_create_file(name
, mode
, parent
, data
,
538 fops
? &debugfs_open_proxy_file_operations
:
539 &debugfs_noop_file_operations
,
542 EXPORT_SYMBOL_GPL(debugfs_create_file_unsafe
);
545 * debugfs_create_file_size - create a file in the debugfs filesystem
546 * @name: a pointer to a string containing the name of the file to create.
547 * @mode: the permission that the file should have.
548 * @parent: a pointer to the parent dentry for this file. This should be a
549 * directory dentry if set. If this parameter is NULL, then the
550 * file will be created in the root of the debugfs filesystem.
551 * @data: a pointer to something that the caller will want to get to later
552 * on. The inode.i_private pointer will point to this value on
554 * @fops: a pointer to a struct file_operations that should be used for
556 * @file_size: initial file size
558 * This is the basic "create a file" function for debugfs. It allows for a
559 * wide range of flexibility in creating a file, or a directory (if you want
560 * to create a directory, the debugfs_create_dir() function is
561 * recommended to be used instead.)
563 void debugfs_create_file_size(const char *name
, umode_t mode
,
564 struct dentry
*parent
, void *data
,
565 const struct file_operations
*fops
,
568 struct dentry
*de
= debugfs_create_file(name
, mode
, parent
, data
, fops
);
571 d_inode(de
)->i_size
= file_size
;
573 EXPORT_SYMBOL_GPL(debugfs_create_file_size
);
576 * debugfs_create_dir - create a directory in the debugfs filesystem
577 * @name: a pointer to a string containing the name of the directory to
579 * @parent: a pointer to the parent dentry for this file. This should be a
580 * directory dentry if set. If this parameter is NULL, then the
581 * directory will be created in the root of the debugfs filesystem.
583 * This function creates a directory in debugfs with the given name.
585 * This function will return a pointer to a dentry if it succeeds. This
586 * pointer must be passed to the debugfs_remove() function when the file is
587 * to be removed (no automatic cleanup happens if your module is unloaded,
588 * you are responsible here.) If an error occurs, ERR_PTR(-ERROR) will be
591 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
594 * NOTE: it's expected that most callers should _ignore_ the errors returned
595 * by this function. Other debugfs functions handle the fact that the "dentry"
596 * passed to them could be an error and they don't crash in that case.
597 * Drivers should generally work fine even if debugfs fails to init anyway.
599 struct dentry
*debugfs_create_dir(const char *name
, struct dentry
*parent
)
601 struct dentry
*dentry
= start_creating(name
, parent
);
607 if (!(debugfs_allow
& DEBUGFS_ALLOW_API
)) {
608 failed_creating(dentry
);
609 return ERR_PTR(-EPERM
);
612 inode
= debugfs_get_inode(dentry
->d_sb
);
613 if (unlikely(!inode
)) {
614 pr_err("out of free dentries, can not create directory '%s'\n",
616 return failed_creating(dentry
);
619 inode
->i_mode
= S_IFDIR
| S_IRWXU
| S_IRUGO
| S_IXUGO
;
620 inode
->i_op
= &debugfs_dir_inode_operations
;
621 inode
->i_fop
= &simple_dir_operations
;
623 /* directory inodes start off with i_nlink == 2 (for "." entry) */
625 d_instantiate(dentry
, inode
);
626 inc_nlink(d_inode(dentry
->d_parent
));
627 fsnotify_mkdir(d_inode(dentry
->d_parent
), dentry
);
628 return end_creating(dentry
);
630 EXPORT_SYMBOL_GPL(debugfs_create_dir
);
633 * debugfs_create_automount - create automount point in the debugfs filesystem
634 * @name: a pointer to a string containing the name of the file to create.
635 * @parent: a pointer to the parent dentry for this file. This should be a
636 * directory dentry if set. If this parameter is NULL, then the
637 * file will be created in the root of the debugfs filesystem.
638 * @f: function to be called when pathname resolution steps on that one.
639 * @data: opaque argument to pass to f().
641 * @f should return what ->d_automount() would.
643 struct dentry
*debugfs_create_automount(const char *name
,
644 struct dentry
*parent
,
645 debugfs_automount_t f
,
648 struct dentry
*dentry
= start_creating(name
, parent
);
649 struct debugfs_fsdata
*fsd
;
655 fsd
= kzalloc(sizeof(*fsd
), GFP_KERNEL
);
657 failed_creating(dentry
);
658 return ERR_PTR(-ENOMEM
);
663 if (!(debugfs_allow
& DEBUGFS_ALLOW_API
)) {
664 failed_creating(dentry
);
666 return ERR_PTR(-EPERM
);
669 inode
= debugfs_get_inode(dentry
->d_sb
);
670 if (unlikely(!inode
)) {
671 pr_err("out of free dentries, can not create automount '%s'\n",
674 return failed_creating(dentry
);
677 make_empty_dir_inode(inode
);
678 inode
->i_flags
|= S_AUTOMOUNT
;
679 inode
->i_private
= data
;
680 dentry
->d_fsdata
= fsd
;
681 /* directory inodes start off with i_nlink == 2 (for "." entry) */
683 d_instantiate(dentry
, inode
);
684 inc_nlink(d_inode(dentry
->d_parent
));
685 fsnotify_mkdir(d_inode(dentry
->d_parent
), dentry
);
686 return end_creating(dentry
);
688 EXPORT_SYMBOL(debugfs_create_automount
);
691 * debugfs_create_symlink- create a symbolic link in the debugfs filesystem
692 * @name: a pointer to a string containing the name of the symbolic link to
694 * @parent: a pointer to the parent dentry for this symbolic link. This
695 * should be a directory dentry if set. If this parameter is NULL,
696 * then the symbolic link will be created in the root of the debugfs
698 * @target: a pointer to a string containing the path to the target of the
701 * This function creates a symbolic link with the given name in debugfs that
702 * links to the given target path.
704 * This function will return a pointer to a dentry if it succeeds. This
705 * pointer must be passed to the debugfs_remove() function when the symbolic
706 * link is to be removed (no automatic cleanup happens if your module is
707 * unloaded, you are responsible here.) If an error occurs, ERR_PTR(-ERROR)
710 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
713 struct dentry
*debugfs_create_symlink(const char *name
, struct dentry
*parent
,
716 struct dentry
*dentry
;
718 char *link
= kstrdup(target
, GFP_KERNEL
);
720 return ERR_PTR(-ENOMEM
);
722 dentry
= start_creating(name
, parent
);
723 if (IS_ERR(dentry
)) {
728 inode
= debugfs_get_inode(dentry
->d_sb
);
729 if (unlikely(!inode
)) {
730 pr_err("out of free dentries, can not create symlink '%s'\n",
733 return failed_creating(dentry
);
735 inode
->i_mode
= S_IFLNK
| S_IRWXUGO
;
736 inode
->i_op
= &debugfs_symlink_inode_operations
;
737 inode
->i_link
= link
;
738 d_instantiate(dentry
, inode
);
739 return end_creating(dentry
);
741 EXPORT_SYMBOL_GPL(debugfs_create_symlink
);
743 static void __debugfs_file_removed(struct dentry
*dentry
)
745 struct debugfs_fsdata
*fsd
;
748 * Paired with the closing smp_mb() implied by a successful
749 * cmpxchg() in debugfs_file_get(): either
750 * debugfs_file_get() must see a dead dentry or we must see a
751 * debugfs_fsdata instance at ->d_fsdata here (or both).
754 fsd
= READ_ONCE(dentry
->d_fsdata
);
755 if ((unsigned long)fsd
& DEBUGFS_FSDATA_IS_REAL_FOPS_BIT
)
758 lock_map_acquire(&fsd
->lockdep_map
);
759 lock_map_release(&fsd
->lockdep_map
);
761 /* if we hit zero, just wait for all to finish */
762 if (!refcount_dec_and_test(&fsd
->active_users
)) {
763 wait_for_completion(&fsd
->active_users_drained
);
767 /* if we didn't hit zero, try to cancel any we can */
768 while (refcount_read(&fsd
->active_users
)) {
769 struct debugfs_cancellation
*c
;
772 * Lock the cancellations. Note that the cancellations
773 * structs are meant to be on the stack, so we need to
774 * ensure we either use them here or don't touch them,
775 * and debugfs_leave_cancellation() will wait for this
776 * to be finished processing before exiting one. It may
777 * of course win and remove the cancellation, but then
778 * chances are we never even got into this bit, we only
779 * do if the refcount isn't zero already.
781 mutex_lock(&fsd
->cancellations_mtx
);
782 while ((c
= list_first_entry_or_null(&fsd
->cancellations
,
783 typeof(*c
), list
))) {
784 list_del_init(&c
->list
);
785 c
->cancel(dentry
, c
->cancel_data
);
787 mutex_unlock(&fsd
->cancellations_mtx
);
789 wait_for_completion(&fsd
->active_users_drained
);
793 static void remove_one(struct dentry
*victim
)
795 if (d_is_reg(victim
))
796 __debugfs_file_removed(victim
);
797 simple_release_fs(&debugfs_mount
, &debugfs_mount_count
);
801 * debugfs_remove - recursively removes a directory
802 * @dentry: a pointer to a the dentry of the directory to be removed. If this
803 * parameter is NULL or an error value, nothing will be done.
805 * This function recursively removes a directory tree in debugfs that
806 * was previously created with a call to another debugfs function
807 * (like debugfs_create_file() or variants thereof.)
809 * This function is required to be called in order for the file to be
810 * removed, no automatic cleanup of files will happen when a module is
811 * removed, you are responsible here.
813 void debugfs_remove(struct dentry
*dentry
)
815 if (IS_ERR_OR_NULL(dentry
))
818 simple_pin_fs(&debug_fs_type
, &debugfs_mount
, &debugfs_mount_count
);
819 simple_recursive_removal(dentry
, remove_one
);
820 simple_release_fs(&debugfs_mount
, &debugfs_mount_count
);
822 EXPORT_SYMBOL_GPL(debugfs_remove
);
825 * debugfs_lookup_and_remove - lookup a directory or file and recursively remove it
826 * @name: a pointer to a string containing the name of the item to look up.
827 * @parent: a pointer to the parent dentry of the item.
829 * This is the equlivant of doing something like
830 * debugfs_remove(debugfs_lookup(..)) but with the proper reference counting
831 * handled for the directory being looked up.
833 void debugfs_lookup_and_remove(const char *name
, struct dentry
*parent
)
835 struct dentry
*dentry
;
837 dentry
= debugfs_lookup(name
, parent
);
841 debugfs_remove(dentry
);
844 EXPORT_SYMBOL_GPL(debugfs_lookup_and_remove
);
847 * debugfs_rename - rename a file/directory in the debugfs filesystem
848 * @old_dir: a pointer to the parent dentry for the renamed object. This
849 * should be a directory dentry.
850 * @old_dentry: dentry of an object to be renamed.
851 * @new_dir: a pointer to the parent dentry where the object should be
852 * moved. This should be a directory dentry.
853 * @new_name: a pointer to a string containing the target name.
855 * This function renames a file/directory in debugfs. The target must not
856 * exist for rename to succeed.
858 * This function will return a pointer to old_dentry (which is updated to
859 * reflect renaming) if it succeeds. If an error occurs, ERR_PTR(-ERROR)
862 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
865 struct dentry
*debugfs_rename(struct dentry
*old_dir
, struct dentry
*old_dentry
,
866 struct dentry
*new_dir
, const char *new_name
)
869 struct dentry
*dentry
= NULL
, *trap
;
870 struct name_snapshot old_name
;
876 if (IS_ERR_OR_NULL(old_dentry
))
879 trap
= lock_rename(new_dir
, old_dir
);
880 /* Source or destination directories don't exist? */
881 if (d_really_is_negative(old_dir
) || d_really_is_negative(new_dir
))
883 /* Source does not exist, cyclic rename, or mountpoint? */
884 if (d_really_is_negative(old_dentry
) || old_dentry
== trap
||
885 d_mountpoint(old_dentry
))
887 dentry
= lookup_one_len(new_name
, new_dir
, strlen(new_name
));
888 /* Lookup failed, cyclic rename or target exists? */
889 if (IS_ERR(dentry
) || dentry
== trap
|| d_really_is_positive(dentry
))
892 take_dentry_name_snapshot(&old_name
, old_dentry
);
894 error
= simple_rename(&nop_mnt_idmap
, d_inode(old_dir
), old_dentry
,
895 d_inode(new_dir
), dentry
, 0);
897 release_dentry_name_snapshot(&old_name
);
900 d_move(old_dentry
, dentry
);
901 fsnotify_move(d_inode(old_dir
), d_inode(new_dir
), &old_name
.name
,
902 d_is_dir(old_dentry
),
904 release_dentry_name_snapshot(&old_name
);
905 unlock_rename(new_dir
, old_dir
);
909 if (dentry
&& !IS_ERR(dentry
))
911 unlock_rename(new_dir
, old_dir
);
914 return ERR_PTR(-EINVAL
);
916 EXPORT_SYMBOL_GPL(debugfs_rename
);
919 * debugfs_initialized - Tells whether debugfs has been registered
921 bool debugfs_initialized(void)
923 return debugfs_registered
;
925 EXPORT_SYMBOL_GPL(debugfs_initialized
);
927 static int __init
debugfs_kernel(char *str
)
930 if (!strcmp(str
, "on"))
931 debugfs_allow
= DEBUGFS_ALLOW_API
| DEBUGFS_ALLOW_MOUNT
;
932 else if (!strcmp(str
, "no-mount"))
933 debugfs_allow
= DEBUGFS_ALLOW_API
;
934 else if (!strcmp(str
, "off"))
940 early_param("debugfs", debugfs_kernel
);
941 static int __init
debugfs_init(void)
945 if (!(debugfs_allow
& DEBUGFS_ALLOW_MOUNT
))
948 retval
= sysfs_create_mount_point(kernel_kobj
, "debug");
952 retval
= register_filesystem(&debug_fs_type
);
954 sysfs_remove_mount_point(kernel_kobj
, "debug");
956 debugfs_registered
= true;
960 core_initcall(debugfs_init
);