[linux.git] / fs / debugfs / inode.c

/*
 *  file.c - part of debugfs, a tiny little debug file system
 *
 *  Copyright (C) 2004 Greg Kroah-Hartman <[email protected]>
 *  Copyright (C) 2004 IBM Inc.
 *
 *	This program is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU General Public License version
 *	2 as published by the Free Software Foundation.
 *
 *  debugfs is for people to use instead of /proc or /sys.
 *  See Documentation/DocBook/kernel-api for more details.
 *
 */

/* uncomment to get debug messages from the debug filesystem, ah the irony. */
/* #define DEBUG */

#include <linux/module.h>
#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/pagemap.h>
#include <linux/init.h>
#include <linux/kobject.h>
#include <linux/namei.h>
#include <linux/debugfs.h>
#include <linux/fsnotify.h>
#include <linux/string.h>

#define DEBUGFS_MAGIC	0x64626720

static struct vfsmount *debugfs_mount;
static int debugfs_mount_count;

static struct inode *debugfs_get_inode(struct super_block *sb, int mode, dev_t dev)
{
	struct inode *inode = new_inode(sb);

	if (inode) {
		inode->i_mode = mode;
		inode->i_uid = 0;
		inode->i_gid = 0;
		inode->i_blocks = 0;
		inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
		switch (mode & S_IFMT) {
		default:
			init_special_inode(inode, mode, dev);
			break;
		case S_IFREG:
			inode->i_fop = &debugfs_file_operations;
			break;
		case S_IFLNK:
			inode->i_op = &debugfs_link_operations;
			break;
		case S_IFDIR:
			inode->i_op = &simple_dir_inode_operations;
			inode->i_fop = &simple_dir_operations;

			/* directory inodes start off with i_nlink == 2
			 * (for "." entry) */
			inc_nlink(inode);
			break;
		}
	}
	return inode; 
}

/* SMP-safe */
static int debugfs_mknod(struct inode *dir, struct dentry *dentry,
			 int mode, dev_t dev)
{
	struct inode *inode;
	int error = -EPERM;

	if (dentry->d_inode)
		return -EEXIST;

	inode = debugfs_get_inode(dir->i_sb, mode, dev);
	if (inode) {
		d_instantiate(dentry, inode);
		dget(dentry);
		error = 0;
	}
	return error;
}

static int debugfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
{
	int res;

	mode = (mode & (S_IRWXUGO | S_ISVTX)) | S_IFDIR;
	res = debugfs_mknod(dir, dentry, mode, 0);
	if (!res) {
		inc_nlink(dir);
		fsnotify_mkdir(dir, dentry);
	}
	return res;
}

static int debugfs_link(struct inode *dir, struct dentry *dentry, int mode)
{
	mode = (mode & S_IALLUGO) | S_IFLNK;
	return debugfs_mknod(dir, dentry, mode, 0);
}

static int debugfs_create(struct inode *dir, struct dentry *dentry, int mode)
{
	int res;

	mode = (mode & S_IALLUGO) | S_IFREG;
	res = debugfs_mknod(dir, dentry, mode, 0);
	if (!res)
		fsnotify_create(dir, dentry);
	return res;
}

static inline int debugfs_positive(struct dentry *dentry)
{
	return dentry->d_inode && !d_unhashed(dentry);
}

static int debug_fill_super(struct super_block *sb, void *data, int silent)
{
	static struct tree_descr debug_files[] = {{""}};

	return simple_fill_super(sb, DEBUGFS_MAGIC, debug_files);
}

static int debug_get_sb(struct file_system_type *fs_type,
			int flags, const char *dev_name,
			void *data, struct vfsmount *mnt)
{
	return get_sb_single(fs_type, flags, data, debug_fill_super, mnt);
}

static struct file_system_type debug_fs_type = {
	.owner =	THIS_MODULE,
	.name =		"debugfs",
	.get_sb =	debug_get_sb,
	.kill_sb =	kill_litter_super,
};

static int debugfs_create_by_name(const char *name, mode_t mode,
				  struct dentry *parent,
				  struct dentry **dentry)
{
	int error = 0;

	/* If the parent is not specified, we create it in the root.
	 * We need the root dentry to do this, which is in the super 
	 * block. A pointer to that is in the struct vfsmount that we
	 * have around.
	 */
	if (!parent) {
		if (debugfs_mount && debugfs_mount->mnt_sb) {
			parent = debugfs_mount->mnt_sb->s_root;
		}
	}
	if (!parent) {
		pr_debug("debugfs: Ah! can not find a parent!\n");
		return -EFAULT;
	}

	*dentry = NULL;
	mutex_lock(&parent->d_inode->i_mutex);
	*dentry = lookup_one_len(name, parent, strlen(name));
	if (!IS_ERR(*dentry)) {
		switch (mode & S_IFMT) {
		case S_IFDIR:
			error = debugfs_mkdir(parent->d_inode, *dentry, mode);
			break;
		case S_IFLNK:
			error = debugfs_link(parent->d_inode, *dentry, mode);
			break;
		default:
			error = debugfs_create(parent->d_inode, *dentry, mode);
			break;
		}
		dput(*dentry);
	} else
		error = PTR_ERR(*dentry);
	mutex_unlock(&parent->d_inode->i_mutex);

	return error;
}

/**
 * debugfs_create_file - create a file in the debugfs filesystem
 * @name: a pointer to a string containing the name of the file to create.
 * @mode: the permission that the file should have
 * @parent: a pointer to the parent dentry for this file.  This should be a
 *          directory dentry if set.  If this paramater is NULL, then the
 *          file will be created in the root of the debugfs filesystem.
 * @data: a pointer to something that the caller will want to get to later
 *        on.  The inode.i_private pointer will point to this value on
 *        the open() call.
 * @fops: a pointer to a struct file_operations that should be used for
 *        this file.
 *
 * This is the basic "create a file" function for debugfs.  It allows for a
 * wide range of flexibility in createing a file, or a directory (if you
 * want to create a directory, the debugfs_create_dir() function is
 * recommended to be used instead.)
 *
 * This function will return a pointer to a dentry if it succeeds.  This
 * pointer must be passed to the debugfs_remove() function when the file is
 * to be removed (no automatic cleanup happens if your module is unloaded,
 * you are responsible here.)  If an error occurs, %NULL will be returned.
 *
 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
 * returned.
 */
struct dentry *debugfs_create_file(const char *name, mode_t mode,
				   struct dentry *parent, void *data,
				   const struct file_operations *fops)
{
	struct dentry *dentry = NULL;
	int error;

	pr_debug("debugfs: creating file '%s'\n",name);

	error = simple_pin_fs(&debug_fs_type, &debugfs_mount,
			      &debugfs_mount_count);
	if (error)
		goto exit;

	error = debugfs_create_by_name(name, mode, parent, &dentry);
	if (error) {
		dentry = NULL;
		simple_release_fs(&debugfs_mount, &debugfs_mount_count);
		goto exit;
	}

	if (dentry->d_inode) {
		if (data)
			dentry->d_inode->i_private = data;
		if (fops)
			dentry->d_inode->i_fop = fops;
	}
exit:
	return dentry;
}
EXPORT_SYMBOL_GPL(debugfs_create_file);

/**
 * debugfs_create_dir - create a directory in the debugfs filesystem
 * @name: a pointer to a string containing the name of the directory to
 *        create.
 * @parent: a pointer to the parent dentry for this file.  This should be a
 *          directory dentry if set.  If this paramater is NULL, then the
 *          directory will be created in the root of the debugfs filesystem.
 *
 * This function creates a directory in debugfs with the given name.
 *
 * This function will return a pointer to a dentry if it succeeds.  This
 * pointer must be passed to the debugfs_remove() function when the file is
 * to be removed (no automatic cleanup happens if your module is unloaded,
 * you are responsible here.)  If an error occurs, %NULL will be returned.
 *
 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
 * returned.
 */
struct dentry *debugfs_create_dir(const char *name, struct dentry *parent)
{
	return debugfs_create_file(name, 
				   S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
				   parent, NULL, NULL);
}
EXPORT_SYMBOL_GPL(debugfs_create_dir);

/**
 * debugfs_create_symlink- create a symbolic link in the debugfs filesystem
 * @name: a pointer to a string containing the name of the symbolic link to
 *        create.
 * @parent: a pointer to the parent dentry for this symbolic link.  This
 *          should be a directory dentry if set.  If this paramater is NULL,
 *          then the symbolic link will be created in the root of the debugfs
 *          filesystem.
 * @target: a pointer to a string containing the path to the target of the
 *          symbolic link.
 *
 * This function creates a symbolic link with the given name in debugfs that
 * links to the given target path.
 *
 * This function will return a pointer to a dentry if it succeeds.  This
 * pointer must be passed to the debugfs_remove() function when the symbolic
 * link is to be removed (no automatic cleanup happens if your module is
 * unloaded, you are responsible here.)  If an error occurs, %NULL will be
 * returned.
 *
 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
 * returned.
 */
struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent,
				      const char *target)
{
	struct dentry *result;
	char *link;

	link = kstrdup(target, GFP_KERNEL);
	if (!link)
		return NULL;

	result = debugfs_create_file(name, S_IFLNK | S_IRWXUGO, parent, link,
				     NULL);
	if (!result)
		kfree(link);
	return result;
}
EXPORT_SYMBOL_GPL(debugfs_create_symlink);

/**
 * debugfs_remove - removes a file or directory from the debugfs filesystem
 * @dentry: a pointer to a the dentry of the file or directory to be
 *          removed.
 *
 * This function removes a file or directory in debugfs that was previously
 * created with a call to another debugfs function (like
 * debugfs_create_file() or variants thereof.)
 *
 * This function is required to be called in order for the file to be
 * removed, no automatic cleanup of files will happen when a module is
 * removed, you are responsible here.
 */
void debugfs_remove(struct dentry *dentry)
{
	struct dentry *parent;
	int ret = 0;
	
	if (!dentry)
		return;

	parent = dentry->d_parent;
	if (!parent || !parent->d_inode)
		return;

	mutex_lock(&parent->d_inode->i_mutex);
	if (debugfs_positive(dentry)) {
		if (dentry->d_inode) {
			dget(dentry);
			switch (dentry->d_inode->i_mode & S_IFMT) {
			case S_IFDIR:
				ret = simple_rmdir(parent->d_inode, dentry);
				break;
			case S_IFLNK:
				kfree(dentry->d_inode->i_private);
				/* fall through */
			default:
				simple_unlink(parent->d_inode, dentry);
				break;
			}
			if (!ret)
				d_delete(dentry);
			dput(dentry);
		}
	}
	mutex_unlock(&parent->d_inode->i_mutex);
	simple_release_fs(&debugfs_mount, &debugfs_mount_count);
}
EXPORT_SYMBOL_GPL(debugfs_remove);

/**
 * debugfs_rename - rename a file/directory in the debugfs filesystem
 * @old_dir: a pointer to the parent dentry for the renamed object. This
 *          should be a directory dentry.
 * @old_dentry: dentry of an object to be renamed.
 * @new_dir: a pointer to the parent dentry where the object should be
 *          moved. This should be a directory dentry.
 * @new_name: a pointer to a string containing the target name.
 *
 * This function renames a file/directory in debugfs.  The target must not
 * exist for rename to succeed.
 *
 * This function will return a pointer to old_dentry (which is updated to
 * reflect renaming) if it succeeds. If an error occurs, %NULL will be
 * returned.
 *
 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
 * returned.
 */
struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry,
		struct dentry *new_dir, const char *new_name)
{
	int error;
	struct dentry *dentry = NULL, *trap;
	const char *old_name;

	trap = lock_rename(new_dir, old_dir);
	/* Source or destination directories don't exist? */
	if (!old_dir->d_inode || !new_dir->d_inode)
		goto exit;
	/* Source does not exist, cyclic rename, or mountpoint? */
	if (!old_dentry->d_inode || old_dentry == trap ||
	    d_mountpoint(old_dentry))
		goto exit;
	dentry = lookup_one_len(new_name, new_dir, strlen(new_name));
	/* Lookup failed, cyclic rename or target exists? */
	if (IS_ERR(dentry) || dentry == trap || dentry->d_inode)
		goto exit;

	old_name = fsnotify_oldname_init(old_dentry->d_name.name);

	error = simple_rename(old_dir->d_inode, old_dentry, new_dir->d_inode,
		dentry);
	if (error) {
		fsnotify_oldname_free(old_name);
		goto exit;
	}
	d_move(old_dentry, dentry);
	fsnotify_move(old_dir->d_inode, new_dir->d_inode, old_name,
		old_dentry->d_name.name, S_ISDIR(old_dentry->d_inode->i_mode),
		NULL, old_dentry);
	fsnotify_oldname_free(old_name);
	unlock_rename(new_dir, old_dir);
	dput(dentry);
	return old_dentry;
exit:
	if (dentry && !IS_ERR(dentry))
		dput(dentry);
	unlock_rename(new_dir, old_dir);
	return NULL;
}
EXPORT_SYMBOL_GPL(debugfs_rename);

static struct kobject *debug_kobj;

static int __init debugfs_init(void)
{
	int retval;

	debug_kobj = kobject_create_and_add("debug", kernel_kobj);
	if (!debug_kobj)
		return -EINVAL;

	retval = register_filesystem(&debug_fs_type);
	if (retval)
		kobject_put(debug_kobj);
	return retval;
}

static void __exit debugfs_exit(void)
{
	simple_release_fs(&debugfs_mount, &debugfs_mount_count);
	unregister_filesystem(&debug_fs_type);
	kobject_put(debug_kobj);
}

core_initcall(debugfs_init);
module_exit(debugfs_exit);
MODULE_LICENSE("GPL");
Commit	Line	Data
1da177e4 LT	1	/*
	2	* file.c - part of debugfs, a tiny little debug file system
	3	*
	4	* Copyright (C) 2004 Greg Kroah-Hartman <[email protected]>
	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
1da177e4 LT	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>
4d8ebddc	24	#include <linux/kobject.h>
1da177e4 LT	25	#include <linux/namei.h>
1da177e4 LT	26	#include <linux/debugfs.h>
4f36557f	27	#include <linux/fsnotify.h>
66f54963	28	#include <linux/string.h>
1da177e4 LT	29
	30	#define DEBUGFS_MAGIC 0x64626720
	31
1da177e4 LT	32	static struct vfsmount *debugfs_mount;
	33	static int debugfs_mount_count;
	34
	35	static struct inode debugfs_get_inode(struct super_block sb, int mode, dev_t dev)
	36	{
	37	struct inode *inode = new_inode(sb);
	38
	39	if (inode) {
	40	inode->i_mode = mode;
	41	inode->i_uid = 0;
	42	inode->i_gid = 0;
1da177e4 LT	43	inode->i_blocks = 0;
	44	inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
	45	switch (mode & S_IFMT) {
	46	default:
	47	init_special_inode(inode, mode, dev);
	48	break;
	49	case S_IFREG:
	50	inode->i_fop = &debugfs_file_operations;
	51	break;
66f54963 PO	52	case S_IFLNK:
	53	inode->i_op = &debugfs_link_operations;
	54	break;
1da177e4 LT	55	case S_IFDIR:
	56	inode->i_op = &simple_dir_inode_operations;
	57	inode->i_fop = &simple_dir_operations;
	58
bafb232e MD	59	/* directory inodes start off with i_nlink == 2
bafb232e MD	60	* (for "." entry) */
d8c76e6f	61	inc_nlink(inode);
1da177e4 LT	62	break;
	63	}
	64	}
	65	return inode;
	66	}
	67
	68	/* SMP-safe */
	69	static int debugfs_mknod(struct inode dir, struct dentry dentry,
	70	int mode, dev_t dev)
	71	{
71601e2b	72	struct inode *inode;
1da177e4 LT	73	int error = -EPERM;
	74
	75	if (dentry->d_inode)
	76	return -EEXIST;
	77
71601e2b	78	inode = debugfs_get_inode(dir->i_sb, mode, dev);
1da177e4 LT	79	if (inode) {
	80	d_instantiate(dentry, inode);
	81	dget(dentry);
	82	error = 0;
	83	}
	84	return error;
	85	}
	86
	87	static int debugfs_mkdir(struct inode dir, struct dentry dentry, int mode)
	88	{
	89	int res;
	90
	91	mode = (mode & (S_IRWXUGO \| S_ISVTX)) \| S_IFDIR;
	92	res = debugfs_mknod(dir, dentry, mode, 0);
4f36557f	93	if (!res) {
d8c76e6f	94	inc_nlink(dir);
4f36557f MD	95	fsnotify_mkdir(dir, dentry);
4f36557f MD	96	}
1da177e4 LT	97	return res;
	98	}
	99
66f54963 PO	100	static int debugfs_link(struct inode dir, struct dentry dentry, int mode)
	101	{
	102	mode = (mode & S_IALLUGO) \| S_IFLNK;
	103	return debugfs_mknod(dir, dentry, mode, 0);
	104	}
	105
1da177e4 LT	106	static int debugfs_create(struct inode dir, struct dentry dentry, int mode)
1da177e4 LT	107	{
4f36557f MD	108	int res;
4f36557f MD	109
1da177e4	110	mode = (mode & S_IALLUGO) \| S_IFREG;
4f36557f MD	111	res = debugfs_mknod(dir, dentry, mode, 0);
	112	if (!res)
	113	fsnotify_create(dir, dentry);
	114	return res;
1da177e4 LT	115	}
	116
	117	static inline int debugfs_positive(struct dentry *dentry)
	118	{
	119	return dentry->d_inode && !d_unhashed(dentry);
	120	}
	121
	122	static int debug_fill_super(struct super_block sb, void data, int silent)
	123	{
	124	static struct tree_descr debug_files[] = {{""}};
	125
	126	return simple_fill_super(sb, DEBUGFS_MAGIC, debug_files);
	127	}
	128
454e2398 DH	129	static int debug_get_sb(struct file_system_type *fs_type,
	130	int flags, const char *dev_name,
	131	void data, struct vfsmount mnt)
1da177e4	132	{
454e2398	133	return get_sb_single(fs_type, flags, data, debug_fill_super, mnt);
1da177e4 LT	134	}
	135
	136	static struct file_system_type debug_fs_type = {
	137	.owner = THIS_MODULE,
	138	.name = "debugfs",
	139	.get_sb = debug_get_sb,
	140	.kill_sb = kill_litter_super,
	141	};
	142
	143	static int debugfs_create_by_name(const char *name, mode_t mode,
	144	struct dentry *parent,
	145	struct dentry **dentry)
	146	{
	147	int error = 0;
	148
	149	/* If the parent is not specified, we create it in the root.
	150	* We need the root dentry to do this, which is in the super
	151	* block. A pointer to that is in the struct vfsmount that we
	152	* have around.
	153	*/
bafb232e	154	if (!parent) {
1da177e4 LT	155	if (debugfs_mount && debugfs_mount->mnt_sb) {
	156	parent = debugfs_mount->mnt_sb->s_root;
	157	}
	158	}
	159	if (!parent) {
	160	pr_debug("debugfs: Ah! can not find a parent!\n");
	161	return -EFAULT;
	162	}
	163
	164	*dentry = NULL;
1b1dcc1b	165	mutex_lock(&parent->d_inode->i_mutex);
5f45f1a7	166	*dentry = lookup_one_len(name, parent, strlen(name));
7bb0386f	167	if (!IS_ERR(*dentry)) {
66f54963 PO	168	switch (mode & S_IFMT) {
66f54963 PO	169	case S_IFDIR:
1da177e4	170	error = debugfs_mkdir(parent->d_inode, *dentry, mode);
66f54963 PO	171	break;
	172	case S_IFLNK:
	173	error = debugfs_link(parent->d_inode, *dentry, mode);
	174	break;
	175	default:
1da177e4	176	error = debugfs_create(parent->d_inode, *dentry, mode);
66f54963 PO	177	break;
66f54963 PO	178	}
65c33336	179	dput(*dentry);
1da177e4	180	} else
7bb0386f	181	error = PTR_ERR(*dentry);
1b1dcc1b	182	mutex_unlock(&parent->d_inode->i_mutex);
1da177e4 LT	183
	184	return error;
	185	}
	186
	187	/**
	188	* debugfs_create_file - create a file in the debugfs filesystem
1da177e4 LT	189	* @name: a pointer to a string containing the name of the file to create.
	190	* @mode: the permission that the file should have
	191	* @parent: a pointer to the parent dentry for this file. This should be a
	192	* directory dentry if set. If this paramater is NULL, then the
	193	* file will be created in the root of the debugfs filesystem.
	194	* @data: a pointer to something that the caller will want to get to later
8e18e294	195	* on. The inode.i_private pointer will point to this value on
1da177e4 LT	196	* the open() call.
	197	* @fops: a pointer to a struct file_operations that should be used for
	198	* this file.
	199	*
	200	* This is the basic "create a file" function for debugfs. It allows for a
	201	* wide range of flexibility in createing a file, or a directory (if you
	202	* want to create a directory, the debugfs_create_dir() function is
	203	* recommended to be used instead.)
	204	*
	205	* This function will return a pointer to a dentry if it succeeds. This
	206	* pointer must be passed to the debugfs_remove() function when the file is
	207	* to be removed (no automatic cleanup happens if your module is unloaded,
6468b3af	208	* you are responsible here.) If an error occurs, %NULL will be returned.
1da177e4	209	*
6468b3af	210	* If debugfs is not enabled in the kernel, the value -%ENODEV will be
873760fb	211	* returned.
1da177e4 LT	212	*/
	213	struct dentry debugfs_create_file(const char name, mode_t mode,
	214	struct dentry parent, void data,
99ac48f5	215	const struct file_operations *fops)
1da177e4 LT	216	{
	217	struct dentry *dentry = NULL;
	218	int error;
	219
	220	pr_debug("debugfs: creating file '%s'\n",name);
	221
63223a06 MD	222	error = simple_pin_fs(&debug_fs_type, &debugfs_mount,
63223a06 MD	223	&debugfs_mount_count);
1da177e4 LT	224	if (error)
	225	goto exit;
	226
	227	error = debugfs_create_by_name(name, mode, parent, &dentry);
	228	if (error) {
	229	dentry = NULL;
63223a06	230	simple_release_fs(&debugfs_mount, &debugfs_mount_count);
1da177e4 LT	231	goto exit;
	232	}
	233
	234	if (dentry->d_inode) {
	235	if (data)
8e18e294	236	dentry->d_inode->i_private = data;
1da177e4 LT	237	if (fops)
	238	dentry->d_inode->i_fop = fops;
	239	}
	240	exit:
	241	return dentry;
	242	}
	243	EXPORT_SYMBOL_GPL(debugfs_create_file);
	244
	245	/**
	246	* debugfs_create_dir - create a directory in the debugfs filesystem
1da177e4 LT	247	* @name: a pointer to a string containing the name of the directory to
	248	* create.
	249	* @parent: a pointer to the parent dentry for this file. This should be a
	250	* directory dentry if set. If this paramater is NULL, then the
	251	* directory will be created in the root of the debugfs filesystem.
	252	*
	253	* This function creates a directory in debugfs with the given name.
	254	*
	255	* This function will return a pointer to a dentry if it succeeds. This
	256	* pointer must be passed to the debugfs_remove() function when the file is
	257	* to be removed (no automatic cleanup happens if your module is unloaded,
6468b3af	258	* you are responsible here.) If an error occurs, %NULL will be returned.
1da177e4	259	*
6468b3af	260	* If debugfs is not enabled in the kernel, the value -%ENODEV will be
873760fb	261	* returned.
1da177e4 LT	262	*/
	263	struct dentry debugfs_create_dir(const char name, struct dentry *parent)
	264	{
	265	return debugfs_create_file(name,
	266	S_IFDIR \| S_IRWXU \| S_IRUGO \| S_IXUGO,
	267	parent, NULL, NULL);
	268	}
	269	EXPORT_SYMBOL_GPL(debugfs_create_dir);
	270
66f54963 PO	271	/**
	272	* debugfs_create_symlink- create a symbolic link in the debugfs filesystem
	273	* @name: a pointer to a string containing the name of the symbolic link to
	274	* create.
	275	* @parent: a pointer to the parent dentry for this symbolic link. This
	276	* should be a directory dentry if set. If this paramater is NULL,
	277	* then the symbolic link will be created in the root of the debugfs
	278	* filesystem.
	279	* @target: a pointer to a string containing the path to the target of the
	280	* symbolic link.
	281	*
	282	* This function creates a symbolic link with the given name in debugfs that
	283	* links to the given target path.
	284	*
	285	* This function will return a pointer to a dentry if it succeeds. This
	286	* pointer must be passed to the debugfs_remove() function when the symbolic
	287	* link is to be removed (no automatic cleanup happens if your module is
	288	* unloaded, you are responsible here.) If an error occurs, %NULL will be
	289	* returned.
	290	*
	291	* If debugfs is not enabled in the kernel, the value -%ENODEV will be
873760fb	292	* returned.
66f54963 PO	293	*/
	294	struct dentry debugfs_create_symlink(const char name, struct dentry *parent,
	295	const char *target)
	296	{
	297	struct dentry *result;
	298	char *link;
	299
	300	link = kstrdup(target, GFP_KERNEL);
	301	if (!link)
	302	return NULL;
	303
	304	result = debugfs_create_file(name, S_IFLNK \| S_IRWXUGO, parent, link,
	305	NULL);
	306	if (!result)
	307	kfree(link);
	308	return result;
	309	}
	310	EXPORT_SYMBOL_GPL(debugfs_create_symlink);
	311
1da177e4 LT	312	/**
1da177e4 LT	313	* debugfs_remove - removes a file or directory from the debugfs filesystem
1da177e4 LT	314	* @dentry: a pointer to a the dentry of the file or directory to be
	315	* removed.
	316	*
	317	* This function removes a file or directory in debugfs that was previously
	318	* created with a call to another debugfs function (like
5a65980e	319	* debugfs_create_file() or variants thereof.)
1da177e4 LT	320	*
	321	* This function is required to be called in order for the file to be
	322	* removed, no automatic cleanup of files will happen when a module is
	323	* removed, you are responsible here.
	324	*/
	325	void debugfs_remove(struct dentry *dentry)
	326	{
	327	struct dentry *parent;
65c33336	328	int ret = 0;
1da177e4 LT	329
	330	if (!dentry)
	331	return;
	332
	333	parent = dentry->d_parent;
	334	if (!parent \|\| !parent->d_inode)
	335	return;
	336
1b1dcc1b	337	mutex_lock(&parent->d_inode->i_mutex);
1da177e4 LT	338	if (debugfs_positive(dentry)) {
1da177e4 LT	339	if (dentry->d_inode) {
29a7f3ad	340	dget(dentry);
66f54963 PO	341	switch (dentry->d_inode->i_mode & S_IFMT) {
66f54963 PO	342	case S_IFDIR:
65c33336	343	ret = simple_rmdir(parent->d_inode, dentry);
66f54963 PO	344	break;
	345	case S_IFLNK:
	346	kfree(dentry->d_inode->i_private);
	347	/* fall through */
	348	default:
1da177e4	349	simple_unlink(parent->d_inode, dentry);
66f54963 PO	350	break;
66f54963 PO	351	}
29a7f3ad MD	352	if (!ret)
	353	d_delete(dentry);
	354	dput(dentry);
1da177e4 LT	355	}
1da177e4 LT	356	}
1b1dcc1b	357	mutex_unlock(&parent->d_inode->i_mutex);
1da177e4 LT	358	simple_release_fs(&debugfs_mount, &debugfs_mount_count);
	359	}
	360	EXPORT_SYMBOL_GPL(debugfs_remove);
	361
cfc94cdf JK	362	/**
	363	* debugfs_rename - rename a file/directory in the debugfs filesystem
	364	* @old_dir: a pointer to the parent dentry for the renamed object. This
	365	* should be a directory dentry.
	366	* @old_dentry: dentry of an object to be renamed.
	367	* @new_dir: a pointer to the parent dentry where the object should be
	368	* moved. This should be a directory dentry.
	369	* @new_name: a pointer to a string containing the target name.
	370	*
	371	* This function renames a file/directory in debugfs. The target must not
	372	* exist for rename to succeed.
	373	*
	374	* This function will return a pointer to old_dentry (which is updated to
	375	* reflect renaming) if it succeeds. If an error occurs, %NULL will be
	376	* returned.
	377	*
	378	* If debugfs is not enabled in the kernel, the value -%ENODEV will be
	379	* returned.
	380	*/
	381	struct dentry debugfs_rename(struct dentry old_dir, struct dentry *old_dentry,
	382	struct dentry new_dir, const char new_name)
	383	{
	384	int error;
	385	struct dentry dentry = NULL, trap;
	386	const char *old_name;
	387
	388	trap = lock_rename(new_dir, old_dir);
	389	/* Source or destination directories don't exist? */
	390	if (!old_dir->d_inode \|\| !new_dir->d_inode)
	391	goto exit;
	392	/* Source does not exist, cyclic rename, or mountpoint? */
	393	if (!old_dentry->d_inode \|\| old_dentry == trap \|\|
	394	d_mountpoint(old_dentry))
	395	goto exit;
	396	dentry = lookup_one_len(new_name, new_dir, strlen(new_name));
	397	/* Lookup failed, cyclic rename or target exists? */
	398	if (IS_ERR(dentry) \|\| dentry == trap \|\| dentry->d_inode)
	399	goto exit;
	400
	401	old_name = fsnotify_oldname_init(old_dentry->d_name.name);
	402
	403	error = simple_rename(old_dir->d_inode, old_dentry, new_dir->d_inode,
	404	dentry);
	405	if (error) {
	406	fsnotify_oldname_free(old_name);
	407	goto exit;
	408	}
	409	d_move(old_dentry, dentry);
	410	fsnotify_move(old_dir->d_inode, new_dir->d_inode, old_name,
	411	old_dentry->d_name.name, S_ISDIR(old_dentry->d_inode->i_mode),
5a190ae6	412	NULL, old_dentry);
cfc94cdf JK	413	fsnotify_oldname_free(old_name);
	414	unlock_rename(new_dir, old_dir);
	415	dput(dentry);
	416	return old_dentry;
	417	exit:
	418	if (dentry && !IS_ERR(dentry))
	419	dput(dentry);
	420	unlock_rename(new_dir, old_dir);
	421	return NULL;
	422	}
	423	EXPORT_SYMBOL_GPL(debugfs_rename);
	424
191e186b	425	static struct kobject *debug_kobj;
1da177e4 LT	426
	427	static int __init debugfs_init(void)
	428	{
	429	int retval;
	430
0ff21e46	431	debug_kobj = kobject_create_and_add("debug", kernel_kobj);
191e186b GKH	432	if (!debug_kobj)
191e186b GKH	433	return -EINVAL;
1da177e4 LT	434
	435	retval = register_filesystem(&debug_fs_type);
	436	if (retval)
197b12d6	437	kobject_put(debug_kobj);
1da177e4 LT	438	return retval;
	439	}
	440
	441	static void __exit debugfs_exit(void)
	442	{
	443	simple_release_fs(&debugfs_mount, &debugfs_mount_count);
	444	unregister_filesystem(&debug_fs_type);
197b12d6	445	kobject_put(debug_kobj);
1da177e4 LT	446	}
	447
	448	core_initcall(debugfs_init);
	449	module_exit(debugfs_exit);
	450	MODULE_LICENSE("GPL");
	451