[deliverable/linux.git] / fs / sysfs / dir.c

/*
 * dir.c - Operations for sysfs directories.
 */

#undef DEBUG

#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/module.h>
#include <linux/kobject.h>
#include "sysfs.h"

DECLARE_RWSEM(sysfs_rename_sem);

static void sysfs_d_iput(struct dentry * dentry, struct inode * inode)
{
	struct sysfs_dirent * sd = dentry->d_fsdata;

	if (sd) {
		BUG_ON(sd->s_dentry != dentry);
		sd->s_dentry = NULL;
		sysfs_put(sd);
	}
	iput(inode);
}

static struct dentry_operations sysfs_dentry_ops = {
	.d_iput		= sysfs_d_iput,
};

/*
 * Allocates a new sysfs_dirent and links it to the parent sysfs_dirent
 */
static struct sysfs_dirent * sysfs_new_dirent(struct sysfs_dirent * parent_sd,
						void * element)
{
	struct sysfs_dirent * sd;

	sd = kmem_cache_alloc(sysfs_dir_cachep, GFP_KERNEL);
	if (!sd)
		return NULL;

	memset(sd, 0, sizeof(*sd));
	atomic_set(&sd->s_count, 1);
	INIT_LIST_HEAD(&sd->s_children);
	list_add(&sd->s_sibling, &parent_sd->s_children);
	sd->s_element = element;

	return sd;
}

int sysfs_make_dirent(struct sysfs_dirent * parent_sd, struct dentry * dentry,
			void * element, umode_t mode, int type)
{
	struct sysfs_dirent * sd;

	sd = sysfs_new_dirent(parent_sd, element);
	if (!sd)
		return -ENOMEM;

	sd->s_mode = mode;
	sd->s_type = type;
	sd->s_dentry = dentry;
	if (dentry) {
		dentry->d_fsdata = sysfs_get(sd);
		dentry->d_op = &sysfs_dentry_ops;
	}

	return 0;
}

static int init_dir(struct inode * inode)
{
	inode->i_op = &sysfs_dir_inode_operations;
	inode->i_fop = &sysfs_dir_operations;

	/* directory inodes start off with i_nlink == 2 (for "." entry) */
	inode->i_nlink++;
	return 0;
}

static int init_file(struct inode * inode)
{
	inode->i_size = PAGE_SIZE;
	inode->i_fop = &sysfs_file_operations;
	return 0;
}

static int init_symlink(struct inode * inode)
{
	inode->i_op = &sysfs_symlink_inode_operations;
	return 0;
}

static int create_dir(struct kobject * k, struct dentry * p,
		      const char * n, struct dentry ** d)
{
	int error;
	umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;

	down(&p->d_inode->i_sem);
	*d = sysfs_get_dentry(p,n);
	if (!IS_ERR(*d)) {
		error = sysfs_make_dirent(p->d_fsdata, *d, k, mode, SYSFS_DIR);
		if (!error) {
			error = sysfs_create(*d, mode, init_dir);
			if (!error) {
				p->d_inode->i_nlink++;
				(*d)->d_op = &sysfs_dentry_ops;
				d_rehash(*d);
			}
		}
		if (error && (error != -EEXIST)) {
			sysfs_put((*d)->d_fsdata);
			d_drop(*d);
		}
		dput(*d);
	} else
		error = PTR_ERR(*d);
	up(&p->d_inode->i_sem);
	return error;
}


int sysfs_create_subdir(struct kobject * k, const char * n, struct dentry ** d)
{
	return create_dir(k,k->dentry,n,d);
}

/**
 *	sysfs_create_dir - create a directory for an object.
 *	@parent:	parent parent object.
 *	@kobj:		object we're creating directory for. 
 */

int sysfs_create_dir(struct kobject * kobj)
{
	struct dentry * dentry = NULL;
	struct dentry * parent;
	int error = 0;

	BUG_ON(!kobj);

	if (kobj->parent)
		parent = kobj->parent->dentry;
	else if (sysfs_mount && sysfs_mount->mnt_sb)
		parent = sysfs_mount->mnt_sb->s_root;
	else
		return -EFAULT;

	error = create_dir(kobj,parent,kobject_name(kobj),&dentry);
	if (!error)
		kobj->dentry = dentry;
	return error;
}

/* attaches attribute's sysfs_dirent to the dentry corresponding to the
 * attribute file
 */
static int sysfs_attach_attr(struct sysfs_dirent * sd, struct dentry * dentry)
{
	struct attribute * attr = NULL;
	struct bin_attribute * bin_attr = NULL;
	int (* init) (struct inode *) = NULL;
	int error = 0;

        if (sd->s_type & SYSFS_KOBJ_BIN_ATTR) {
                bin_attr = sd->s_element;
                attr = &bin_attr->attr;
        } else {
                attr = sd->s_element;
                init = init_file;
        }

	dentry->d_fsdata = sysfs_get(sd);
	sd->s_dentry = dentry;
	error = sysfs_create(dentry, (attr->mode & S_IALLUGO) | S_IFREG, init);
	if (error) {
		sysfs_put(sd);
		return error;
	}

        if (bin_attr) {
		dentry->d_inode->i_size = bin_attr->size;
		dentry->d_inode->i_fop = &bin_fops;
	}
	dentry->d_op = &sysfs_dentry_ops;
	d_rehash(dentry);

	return 0;
}

static int sysfs_attach_link(struct sysfs_dirent * sd, struct dentry * dentry)
{
	int err = 0;

	dentry->d_fsdata = sysfs_get(sd);
	sd->s_dentry = dentry;
	err = sysfs_create(dentry, S_IFLNK|S_IRWXUGO, init_symlink);
	if (!err) {
		dentry->d_op = &sysfs_dentry_ops;
		d_rehash(dentry);
	} else
		sysfs_put(sd);

	return err;
}

static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry,
				struct nameidata *nd)
{
	struct sysfs_dirent * parent_sd = dentry->d_parent->d_fsdata;
	struct sysfs_dirent * sd;
	int err = 0;

	list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
		if (sd->s_type & SYSFS_NOT_PINNED) {
			const unsigned char * name = sysfs_get_name(sd);

			if (strcmp(name, dentry->d_name.name))
				continue;

			if (sd->s_type & SYSFS_KOBJ_LINK)
				err = sysfs_attach_link(sd, dentry);
			else
				err = sysfs_attach_attr(sd, dentry);
			break;
		}
	}

	return ERR_PTR(err);
}

struct inode_operations sysfs_dir_inode_operations = {
	.lookup		= sysfs_lookup,
};

static void remove_dir(struct dentry * d)
{
	struct dentry * parent = dget(d->d_parent);
	struct sysfs_dirent * sd;

	down(&parent->d_inode->i_sem);
	d_delete(d);
	sd = d->d_fsdata;
 	list_del_init(&sd->s_sibling);
	sysfs_put(sd);
	if (d->d_inode)
		simple_rmdir(parent->d_inode,d);

	pr_debug(" o %s removing done (%d)\n",d->d_name.name,
		 atomic_read(&d->d_count));

	up(&parent->d_inode->i_sem);
	dput(parent);
}

void sysfs_remove_subdir(struct dentry * d)
{
	remove_dir(d);
}


/**
 *	sysfs_remove_dir - remove an object's directory.
 *	@kobj:	object. 
 *
 *	The only thing special about this is that we remove any files in 
 *	the directory before we remove the directory, and we've inlined
 *	what used to be sysfs_rmdir() below, instead of calling separately.
 */

void sysfs_remove_dir(struct kobject * kobj)
{
	struct dentry * dentry = dget(kobj->dentry);
	struct sysfs_dirent * parent_sd;
	struct sysfs_dirent * sd, * tmp;

	if (!dentry)
		return;

	pr_debug("sysfs %s: removing dir\n",dentry->d_name.name);
	down(&dentry->d_inode->i_sem);
	parent_sd = dentry->d_fsdata;
	list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) {
		if (!sd->s_element || !(sd->s_type & SYSFS_NOT_PINNED))
			continue;
		list_del_init(&sd->s_sibling);
		sysfs_drop_dentry(sd, dentry);
		sysfs_put(sd);
	}
	up(&dentry->d_inode->i_sem);

	remove_dir(dentry);
	/**
	 * Drop reference from dget() on entrance.
	 */
	dput(dentry);
}

int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
{
	int error = 0;
	struct dentry * new_dentry, * parent;

	if (!strcmp(kobject_name(kobj), new_name))
		return -EINVAL;

	if (!kobj->parent)
		return -EINVAL;

	down_write(&sysfs_rename_sem);
	parent = kobj->parent->dentry;

	down(&parent->d_inode->i_sem);

	new_dentry = sysfs_get_dentry(parent, new_name);
	if (!IS_ERR(new_dentry)) {
  		if (!new_dentry->d_inode) {
			error = kobject_set_name(kobj, "%s", new_name);
			if (!error) {
				d_add(new_dentry, NULL);
				d_move(kobj->dentry, new_dentry);
			}
			else
				d_drop(new_dentry);
		} else
			error = -EEXIST;
		dput(new_dentry);
	}
	up(&parent->d_inode->i_sem);	
	up_write(&sysfs_rename_sem);

	return error;
}

static int sysfs_dir_open(struct inode *inode, struct file *file)
{
	struct dentry * dentry = file->f_dentry;
	struct sysfs_dirent * parent_sd = dentry->d_fsdata;

	down(&dentry->d_inode->i_sem);
	file->private_data = sysfs_new_dirent(parent_sd, NULL);
	up(&dentry->d_inode->i_sem);

	return file->private_data ? 0 : -ENOMEM;

}

static int sysfs_dir_close(struct inode *inode, struct file *file)
{
	struct dentry * dentry = file->f_dentry;
	struct sysfs_dirent * cursor = file->private_data;

	down(&dentry->d_inode->i_sem);
	list_del_init(&cursor->s_sibling);
	up(&dentry->d_inode->i_sem);

	release_sysfs_dirent(cursor);

	return 0;
}

/* Relationship between s_mode and the DT_xxx types */
static inline unsigned char dt_type(struct sysfs_dirent *sd)
{
	return (sd->s_mode >> 12) & 15;
}

static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
{
	struct dentry *dentry = filp->f_dentry;
	struct sysfs_dirent * parent_sd = dentry->d_fsdata;
	struct sysfs_dirent *cursor = filp->private_data;
	struct list_head *p, *q = &cursor->s_sibling;
	ino_t ino;
	int i = filp->f_pos;

	switch (i) {
		case 0:
			ino = dentry->d_inode->i_ino;
			if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
				break;
			filp->f_pos++;
			i++;
			/* fallthrough */
		case 1:
			ino = parent_ino(dentry);
			if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
				break;
			filp->f_pos++;
			i++;
			/* fallthrough */
		default:
			if (filp->f_pos == 2) {
				list_del(q);
				list_add(q, &parent_sd->s_children);
			}
			for (p=q->next; p!= &parent_sd->s_children; p=p->next) {
				struct sysfs_dirent *next;
				const char * name;
				int len;

				next = list_entry(p, struct sysfs_dirent,
						   s_sibling);
				if (!next->s_element)
					continue;

				name = sysfs_get_name(next);
				len = strlen(name);
				if (next->s_dentry)
					ino = next->s_dentry->d_inode->i_ino;
				else
					ino = iunique(sysfs_sb, 2);

				if (filldir(dirent, name, len, filp->f_pos, ino,
						 dt_type(next)) < 0)
					return 0;

				list_del(q);
				list_add(q, p);
				p = q;
				filp->f_pos++;
			}
	}
	return 0;
}

static loff_t sysfs_dir_lseek(struct file * file, loff_t offset, int origin)
{
	struct dentry * dentry = file->f_dentry;

	down(&dentry->d_inode->i_sem);
	switch (origin) {
		case 1:
			offset += file->f_pos;
		case 0:
			if (offset >= 0)
				break;
		default:
			up(&file->f_dentry->d_inode->i_sem);
			return -EINVAL;
	}
	if (offset != file->f_pos) {
		file->f_pos = offset;
		if (file->f_pos >= 2) {
			struct sysfs_dirent *sd = dentry->d_fsdata;
			struct sysfs_dirent *cursor = file->private_data;
			struct list_head *p;
			loff_t n = file->f_pos - 2;

			list_del(&cursor->s_sibling);
			p = sd->s_children.next;
			while (n && p != &sd->s_children) {
				struct sysfs_dirent *next;
				next = list_entry(p, struct sysfs_dirent,
						   s_sibling);
				if (next->s_element)
					n--;
				p = p->next;
			}
			list_add_tail(&cursor->s_sibling, p);
		}
	}
	up(&dentry->d_inode->i_sem);
	return offset;
}

struct file_operations sysfs_dir_operations = {
	.open		= sysfs_dir_open,
	.release	= sysfs_dir_close,
	.llseek		= sysfs_dir_lseek,
	.read		= generic_read_dir,
	.readdir	= sysfs_readdir,
};

EXPORT_SYMBOL_GPL(sysfs_create_dir);
EXPORT_SYMBOL_GPL(sysfs_remove_dir);
EXPORT_SYMBOL_GPL(sysfs_rename_dir);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* dir.c - Operations for sysfs directories.
	3	*/
	4
	5	#undef DEBUG
	6
	7	#include <linux/fs.h>
	8	#include <linux/mount.h>
	9	#include <linux/module.h>
	10	#include <linux/kobject.h>
	11	#include "sysfs.h"
	12
	13	DECLARE_RWSEM(sysfs_rename_sem);
	14
	15	static void sysfs_d_iput(struct dentry * dentry, struct inode * inode)
	16	{
	17	struct sysfs_dirent * sd = dentry->d_fsdata;
	18
	19	if (sd) {
	20	BUG_ON(sd->s_dentry != dentry);
	21	sd->s_dentry = NULL;
	22	sysfs_put(sd);
	23	}
	24	iput(inode);
	25	}
	26
	27	static struct dentry_operations sysfs_dentry_ops = {
	28	.d_iput = sysfs_d_iput,
	29	};
	30
	31	/*
	32	* Allocates a new sysfs_dirent and links it to the parent sysfs_dirent
	33	*/
	34	static struct sysfs_dirent * sysfs_new_dirent(struct sysfs_dirent * parent_sd,
	35	void * element)
	36	{
	37	struct sysfs_dirent * sd;
	38
	39	sd = kmem_cache_alloc(sysfs_dir_cachep, GFP_KERNEL);
	40	if (!sd)
	41	return NULL;
	42
	43	memset(sd, 0, sizeof(*sd));
	44	atomic_set(&sd->s_count, 1);
	45	INIT_LIST_HEAD(&sd->s_children);
	46	list_add(&sd->s_sibling, &parent_sd->s_children);
	47	sd->s_element = element;
	48
	49	return sd;
	50	}
	51
	52	int sysfs_make_dirent(struct sysfs_dirent * parent_sd, struct dentry * dentry,
	53	void * element, umode_t mode, int type)
	54	{
	55	struct sysfs_dirent * sd;
	56
	57	sd = sysfs_new_dirent(parent_sd, element);
	58	if (!sd)
	59	return -ENOMEM;
	60
	61	sd->s_mode = mode;
	62	sd->s_type = type;
	63	sd->s_dentry = dentry;
	64	if (dentry) {
65	dentry->d_fsdata = sysfs_get(sd);
66	dentry->d_op = &sysfs_dentry_ops;
67	}
68
69	return 0;
70	}
71
72	static int init_dir(struct inode * inode)
73	{
74	inode->i_op = &sysfs_dir_inode_operations;
75	inode->i_fop = &sysfs_dir_operations;
76
77	/* directory inodes start off with i_nlink == 2 (for "." entry) */
78	inode->i_nlink++;
79	return 0;
80	}
81
82	static int init_file(struct inode * inode)
83	{
84	inode->i_size = PAGE_SIZE;
85	inode->i_fop = &sysfs_file_operations;
86	return 0;
87	}
88
89	static int init_symlink(struct inode * inode)
90	{
91	inode->i_op = &sysfs_symlink_inode_operations;
92	return 0;
93	}
94
95	static int create_dir(struct kobject * k, struct dentry * p,
96	const char * n, struct dentry ** d)
97	{
98	int error;
99	umode_t mode = S_IFDIR\| S_IRWXU \| S_IRUGO \| S_IXUGO;
100
101	down(&p->d_inode->i_sem);
102	*d = sysfs_get_dentry(p,n);
103	if (!IS_ERR(*d)) {
6fa5c828	104	error = sysfs_make_dirent(p->d_fsdata, *d, k, mode, SYSFS_DIR);
1da177e4	105	if (!error) {
6fa5c828	106	error = sysfs_create(*d, mode, init_dir);
1da177e4 LT	107	if (!error) {
	108	p->d_inode->i_nlink++;
	109	(*d)->d_op = &sysfs_dentry_ops;
	110	d_rehash(*d);
	111	}
	112	}
6fa5c828 MS	113	if (error && (error != -EEXIST)) {
6fa5c828 MS	114	sysfs_put((*d)->d_fsdata);
1da177e4	115	d_drop(*d);
6fa5c828	116	}
1da177e4 LT	117	dput(*d);
	118	} else
	119	error = PTR_ERR(*d);
	120	up(&p->d_inode->i_sem);
	121	return error;
	122	}
	123
	124
	125	int sysfs_create_subdir(struct kobject * k, const char * n, struct dentry ** d)
	126	{
	127	return create_dir(k,k->dentry,n,d);
	128	}
	129
	130	/**
	131	* sysfs_create_dir - create a directory for an object.
	132	* @parent: parent parent object.
	133	* @kobj: object we're creating directory for.
	134	*/
	135
	136	int sysfs_create_dir(struct kobject * kobj)
	137	{
	138	struct dentry * dentry = NULL;
	139	struct dentry * parent;
	140	int error = 0;
	141
	142	BUG_ON(!kobj);
	143
	144	if (kobj->parent)
	145	parent = kobj->parent->dentry;
	146	else if (sysfs_mount && sysfs_mount->mnt_sb)
	147	parent = sysfs_mount->mnt_sb->s_root;
	148	else
	149	return -EFAULT;
	150
	151	error = create_dir(kobj,parent,kobject_name(kobj),&dentry);
	152	if (!error)
	153	kobj->dentry = dentry;
	154	return error;
	155	}
	156
	157	/* attaches attribute's sysfs_dirent to the dentry corresponding to the
	158	* attribute file
	159	*/
	160	static int sysfs_attach_attr(struct sysfs_dirent * sd, struct dentry * dentry)
	161	{
	162	struct attribute * attr = NULL;
	163	struct bin_attribute * bin_attr = NULL;
	164	int (* init) (struct inode *) = NULL;
	165	int error = 0;
	166
	167	if (sd->s_type & SYSFS_KOBJ_BIN_ATTR) {
	168	bin_attr = sd->s_element;
	169	attr = &bin_attr->attr;
	170	} else {
	171	attr = sd->s_element;
	172	init = init_file;
	173	}
	174
6fa5c828 MS	175	dentry->d_fsdata = sysfs_get(sd);
6fa5c828 MS	176	sd->s_dentry = dentry;
1da177e4	177	error = sysfs_create(dentry, (attr->mode & S_IALLUGO) \| S_IFREG, init);
6fa5c828 MS	178	if (error) {
6fa5c828 MS	179	sysfs_put(sd);
1da177e4	180	return error;
6fa5c828	181	}
1da177e4 LT	182
	183	if (bin_attr) {
	184	dentry->d_inode->i_size = bin_attr->size;
	185	dentry->d_inode->i_fop = &bin_fops;
	186	}
	187	dentry->d_op = &sysfs_dentry_ops;
1da177e4 LT	188	d_rehash(dentry);
	189
	190	return 0;
	191	}
	192
	193	static int sysfs_attach_link(struct sysfs_dirent * sd, struct dentry * dentry)
	194	{
	195	int err = 0;
	196
6fa5c828 MS	197	dentry->d_fsdata = sysfs_get(sd);
6fa5c828 MS	198	sd->s_dentry = dentry;
1da177e4 LT	199	err = sysfs_create(dentry, S_IFLNK\|S_IRWXUGO, init_symlink);
	200	if (!err) {
	201	dentry->d_op = &sysfs_dentry_ops;
1da177e4	202	d_rehash(dentry);
6fa5c828 MS	203	} else
	204	sysfs_put(sd);
	205
1da177e4 LT	206	return err;
	207	}
	208
	209	static struct dentry * sysfs_lookup(struct inode dir, struct dentry dentry,
	210	struct nameidata *nd)
	211	{
	212	struct sysfs_dirent * parent_sd = dentry->d_parent->d_fsdata;
	213	struct sysfs_dirent * sd;
	214	int err = 0;
	215
	216	list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
	217	if (sd->s_type & SYSFS_NOT_PINNED) {
	218	const unsigned char * name = sysfs_get_name(sd);
	219
	220	if (strcmp(name, dentry->d_name.name))
	221	continue;
	222
	223	if (sd->s_type & SYSFS_KOBJ_LINK)
	224	err = sysfs_attach_link(sd, dentry);
	225	else
	226	err = sysfs_attach_attr(sd, dentry);
	227	break;
	228	}
	229	}
	230
	231	return ERR_PTR(err);
	232	}
	233
	234	struct inode_operations sysfs_dir_inode_operations = {
	235	.lookup = sysfs_lookup,
	236	};
	237
	238	static void remove_dir(struct dentry * d)
	239	{
	240	struct dentry * parent = dget(d->d_parent);
	241	struct sysfs_dirent * sd;
	242
	243	down(&parent->d_inode->i_sem);
	244	d_delete(d);
	245	sd = d->d_fsdata;
	246	list_del_init(&sd->s_sibling);
	247	sysfs_put(sd);
	248	if (d->d_inode)
	249	simple_rmdir(parent->d_inode,d);
	250
	251	pr_debug(" o %s removing done (%d)\n",d->d_name.name,
	252	atomic_read(&d->d_count));
	253
	254	up(&parent->d_inode->i_sem);
	255	dput(parent);
	256	}
	257
	258	void sysfs_remove_subdir(struct dentry * d)
	259	{
	260	remove_dir(d);
	261	}
	262
	263
	264	/**
	265	* sysfs_remove_dir - remove an object's directory.
	266	* @kobj: object.
	267	*
	268	* The only thing special about this is that we remove any files in
	269	* the directory before we remove the directory, and we've inlined
270	* what used to be sysfs_rmdir() below, instead of calling separately.
271	*/
272
273	void sysfs_remove_dir(struct kobject * kobj)
274	{
275	struct dentry * dentry = dget(kobj->dentry);
276	struct sysfs_dirent * parent_sd;
277	struct sysfs_dirent * sd, * tmp;
278
279	if (!dentry)
280	return;
281
282	pr_debug("sysfs %s: removing dir\n",dentry->d_name.name);
283	down(&dentry->d_inode->i_sem);
284	parent_sd = dentry->d_fsdata;
285	list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) {
286	if (!sd->s_element \|\| !(sd->s_type & SYSFS_NOT_PINNED))
287	continue;
288	list_del_init(&sd->s_sibling);
289	sysfs_drop_dentry(sd, dentry);
290	sysfs_put(sd);
291	}
292	up(&dentry->d_inode->i_sem);
293
294	remove_dir(dentry);
295	/**
296	* Drop reference from dget() on entrance.
297	*/
298	dput(dentry);
299	}
300
301	int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
302	{
303	int error = 0;
304	struct dentry * new_dentry, * parent;
305
306	if (!strcmp(kobject_name(kobj), new_name))
307	return -EINVAL;
308
309	if (!kobj->parent)
310	return -EINVAL;
311
312	down_write(&sysfs_rename_sem);
313	parent = kobj->parent->dentry;
314
315	down(&parent->d_inode->i_sem);
316
317	new_dentry = sysfs_get_dentry(parent, new_name);
318	if (!IS_ERR(new_dentry)) {
319	if (!new_dentry->d_inode) {
320	error = kobject_set_name(kobj, "%s", new_name);
321	if (!error) {
322	d_add(new_dentry, NULL);
323	d_move(kobj->dentry, new_dentry);
324	}
325	else
326	d_drop(new_dentry);
327	} else
328	error = -EEXIST;
329	dput(new_dentry);
330	}
331	up(&parent->d_inode->i_sem);
332	up_write(&sysfs_rename_sem);
333
334	return error;
335	}
336
337	static int sysfs_dir_open(struct inode inode, struct file file)
338	{
339	struct dentry * dentry = file->f_dentry;
340	struct sysfs_dirent * parent_sd = dentry->d_fsdata;
341
342	down(&dentry->d_inode->i_sem);
343	file->private_data = sysfs_new_dirent(parent_sd, NULL);
344	up(&dentry->d_inode->i_sem);
345
346	return file->private_data ? 0 : -ENOMEM;
347
348	}
349
350	static int sysfs_dir_close(struct inode inode, struct file file)
351	{
352	struct dentry * dentry = file->f_dentry;
353	struct sysfs_dirent * cursor = file->private_data;
354
355	down(&dentry->d_inode->i_sem);
356	list_del_init(&cursor->s_sibling);
357	up(&dentry->d_inode->i_sem);
358
359	release_sysfs_dirent(cursor);
360
361	return 0;
362	}
363
364	/* Relationship between s_mode and the DT_xxx types */
365	static inline unsigned char dt_type(struct sysfs_dirent *sd)
366	{
367	return (sd->s_mode >> 12) & 15;
368	}
369
370	static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
371	{
372	struct dentry *dentry = filp->f_dentry;
373	struct sysfs_dirent * parent_sd = dentry->d_fsdata;
374	struct sysfs_dirent *cursor = filp->private_data;
375	struct list_head p, q = &cursor->s_sibling;
376	ino_t ino;
377	int i = filp->f_pos;
378
379	switch (i) {
380	case 0:
381	ino = dentry->d_inode->i_ino;
382	if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
383	break;
384	filp->f_pos++;
385	i++;
386	/* fallthrough */
387	case 1:
388	ino = parent_ino(dentry);
389	if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
390	break;
391	filp->f_pos++;
392	i++;
393	/* fallthrough */
394	default:
395	if (filp->f_pos == 2) {
396	list_del(q);
397	list_add(q, &parent_sd->s_children);
398	}
399	for (p=q->next; p!= &parent_sd->s_children; p=p->next) {
400	struct sysfs_dirent *next;
401	const char * name;
402	int len;
403
404	next = list_entry(p, struct sysfs_dirent,
405	s_sibling);
406	if (!next->s_element)
407	continue;
408
409	name = sysfs_get_name(next);
410	len = strlen(name);
411	if (next->s_dentry)
412	ino = next->s_dentry->d_inode->i_ino;
413	else
414	ino = iunique(sysfs_sb, 2);
415
416	if (filldir(dirent, name, len, filp->f_pos, ino,
417	dt_type(next)) < 0)
418	return 0;
419
420	list_del(q);
421	list_add(q, p);
422	p = q;
423	filp->f_pos++;
424	}
425	}
426	return 0;
427	}
428
429	static loff_t sysfs_dir_lseek(struct file * file, loff_t offset, int origin)
430	{
431	struct dentry * dentry = file->f_dentry;
432
433	down(&dentry->d_inode->i_sem);
434	switch (origin) {
435	case 1:
436	offset += file->f_pos;
437	case 0:
438	if (offset >= 0)
439	break;
440	default:
441	up(&file->f_dentry->d_inode->i_sem);
442	return -EINVAL;
443	}
444	if (offset != file->f_pos) {
445	file->f_pos = offset;
446	if (file->f_pos >= 2) {
447	struct sysfs_dirent *sd = dentry->d_fsdata;
448	struct sysfs_dirent *cursor = file->private_data;
449	struct list_head *p;
450	loff_t n = file->f_pos - 2;
451
452	list_del(&cursor->s_sibling);
453	p = sd->s_children.next;
454	while (n && p != &sd->s_children) {
455	struct sysfs_dirent *next;
456	next = list_entry(p, struct sysfs_dirent,
457	s_sibling);
458	if (next->s_element)
459	n--;
460	p = p->next;
461	}
462	list_add_tail(&cursor->s_sibling, p);
463	}
464	}
465	up(&dentry->d_inode->i_sem);
466	return offset;
467	}
468
469	struct file_operations sysfs_dir_operations = {
470	.open = sysfs_dir_open,
471	.release = sysfs_dir_close,
472	.llseek = sysfs_dir_lseek,
473	.read = generic_read_dir,
474	.readdir = sysfs_readdir,
475	};
476
477	EXPORT_SYMBOL_GPL(sysfs_create_dir);
478	EXPORT_SYMBOL_GPL(sysfs_remove_dir);
479	EXPORT_SYMBOL_GPL(sysfs_rename_dir);
480