[net-next-2.6.git] / fs / sysfs / inode.c

/*
 * fs/sysfs/inode.c - basic sysfs inode and dentry operations
 *
 * Copyright (c) 2001-3 Patrick Mochel
 * Copyright (c) 2007 SUSE Linux Products GmbH
 * Copyright (c) 2007 Tejun Heo <teheo@suse.de>
 *
 * This file is released under the GPLv2.
 *
 * Please see Documentation/filesystems/sysfs.txt for more information.
 */

#undef DEBUG 

#include <linux/pagemap.h>
#include <linux/namei.h>
#include <linux/backing-dev.h>
#include <linux/capability.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/xattr.h>
#include <linux/security.h>
#include "sysfs.h"

extern struct super_block * sysfs_sb;

static const struct address_space_operations sysfs_aops = {
	.readpage	= simple_readpage,
	.write_begin	= simple_write_begin,
	.write_end	= simple_write_end,
};

static struct backing_dev_info sysfs_backing_dev_info = {
	.name		= "sysfs",
	.ra_pages	= 0,	/* No readahead */
	.capabilities	= BDI_CAP_NO_ACCT_AND_WRITEBACK,
};

static const struct inode_operations sysfs_inode_operations ={
	.permission	= sysfs_permission,
	.setattr	= sysfs_setattr,
	.getattr	= sysfs_getattr,
	.setxattr	= sysfs_setxattr,
};

int __init sysfs_inode_init(void)
{
	return bdi_init(&sysfs_backing_dev_info);
}

static struct sysfs_inode_attrs *sysfs_init_inode_attrs(struct sysfs_dirent *sd)
{
	struct sysfs_inode_attrs *attrs;
	struct iattr *iattrs;

	attrs = kzalloc(sizeof(struct sysfs_inode_attrs), GFP_KERNEL);
	if (!attrs)
		return NULL;
	iattrs = &attrs->ia_iattr;

	/* assign default attributes */
	iattrs->ia_mode = sd->s_mode;
	iattrs->ia_uid = 0;
	iattrs->ia_gid = 0;
	iattrs->ia_atime = iattrs->ia_mtime = iattrs->ia_ctime = CURRENT_TIME;

	return attrs;
}

int sysfs_sd_setattr(struct sysfs_dirent *sd, struct iattr * iattr)
{
	struct sysfs_inode_attrs *sd_attrs;
	struct iattr *iattrs;
	unsigned int ia_valid = iattr->ia_valid;

	sd_attrs = sd->s_iattr;

	if (!sd_attrs) {
		/* setting attributes for the first time, allocate now */
		sd_attrs = sysfs_init_inode_attrs(sd);
		if (!sd_attrs)
			return -ENOMEM;
		sd->s_iattr = sd_attrs;
	}
	/* attributes were changed at least once in past */
	iattrs = &sd_attrs->ia_iattr;

	if (ia_valid & ATTR_UID)
		iattrs->ia_uid = iattr->ia_uid;
	if (ia_valid & ATTR_GID)
		iattrs->ia_gid = iattr->ia_gid;
	if (ia_valid & ATTR_ATIME)
		iattrs->ia_atime = iattr->ia_atime;
	if (ia_valid & ATTR_MTIME)
		iattrs->ia_mtime = iattr->ia_mtime;
	if (ia_valid & ATTR_CTIME)
		iattrs->ia_ctime = iattr->ia_ctime;
	if (ia_valid & ATTR_MODE) {
		umode_t mode = iattr->ia_mode;
		iattrs->ia_mode = sd->s_mode = mode;
	}
	return 0;
}

int sysfs_setattr(struct dentry *dentry, struct iattr *iattr)
{
	struct inode *inode = dentry->d_inode;
	struct sysfs_dirent *sd = dentry->d_fsdata;
	int error;

	if (!sd)
		return -EINVAL;

	mutex_lock(&sysfs_mutex);
	error = inode_change_ok(inode, iattr);
	if (error)
		goto out;

	iattr->ia_valid &= ~ATTR_SIZE; /* ignore size changes */

	error = inode_setattr(inode, iattr);
	if (error)
		goto out;

	error = sysfs_sd_setattr(sd, iattr);
out:
	mutex_unlock(&sysfs_mutex);
	return error;
}

static int sysfs_sd_setsecdata(struct sysfs_dirent *sd, void **secdata, u32 *secdata_len)
{
	struct sysfs_inode_attrs *iattrs;
	void *old_secdata;
	size_t old_secdata_len;

	iattrs = sd->s_iattr;
	if (!iattrs)
		iattrs = sysfs_init_inode_attrs(sd);
	if (!iattrs)
		return -ENOMEM;

	old_secdata = iattrs->ia_secdata;
	old_secdata_len = iattrs->ia_secdata_len;

	iattrs->ia_secdata = *secdata;
	iattrs->ia_secdata_len = *secdata_len;

	*secdata = old_secdata;
	*secdata_len = old_secdata_len;
	return 0;
}

int sysfs_setxattr(struct dentry *dentry, const char *name, const void *value,
		size_t size, int flags)
{
	struct sysfs_dirent *sd = dentry->d_fsdata;
	void *secdata;
	int error;
	u32 secdata_len = 0;

	if (!sd)
		return -EINVAL;

	if (!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN)) {
		const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
		error = security_inode_setsecurity(dentry->d_inode, suffix,
						value, size, flags);
		if (error)
			goto out;
		error = security_inode_getsecctx(dentry->d_inode,
						&secdata, &secdata_len);
		if (error)
			goto out;

		mutex_lock(&sysfs_mutex);
		error = sysfs_sd_setsecdata(sd, &secdata, &secdata_len);
		mutex_unlock(&sysfs_mutex);

		if (secdata)
			security_release_secctx(secdata, secdata_len);
	} else
		return -EINVAL;
out:
	return error;
}

static inline void set_default_inode_attr(struct inode * inode, mode_t mode)
{
	inode->i_mode = mode;
	inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
}

static inline void set_inode_attr(struct inode * inode, struct iattr * iattr)
{
	inode->i_uid = iattr->ia_uid;
	inode->i_gid = iattr->ia_gid;
	inode->i_atime = iattr->ia_atime;
	inode->i_mtime = iattr->ia_mtime;
	inode->i_ctime = iattr->ia_ctime;
}

static int sysfs_count_nlink(struct sysfs_dirent *sd)
{
	struct sysfs_dirent *child;
	int nr = 0;

	for (child = sd->s_dir.children; child; child = child->s_sibling)
		if (sysfs_type(child) == SYSFS_DIR)
			nr++;

	return nr + 2;
}

static void sysfs_refresh_inode(struct sysfs_dirent *sd, struct inode *inode)
{
	struct sysfs_inode_attrs *iattrs = sd->s_iattr;

	inode->i_mode = sd->s_mode;
	if (iattrs) {
		/* sysfs_dirent has non-default attributes
		 * get them from persistent copy in sysfs_dirent
		 */
		set_inode_attr(inode, &iattrs->ia_iattr);
		security_inode_notifysecctx(inode,
					    iattrs->ia_secdata,
					    iattrs->ia_secdata_len);
	}

	if (sysfs_type(sd) == SYSFS_DIR)
		inode->i_nlink = sysfs_count_nlink(sd);
}

int sysfs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
{
	struct sysfs_dirent *sd = dentry->d_fsdata;
	struct inode *inode = dentry->d_inode;

	mutex_lock(&sysfs_mutex);
	sysfs_refresh_inode(sd, inode);
	mutex_unlock(&sysfs_mutex);

	generic_fillattr(inode, stat);
	return 0;
}

static void sysfs_init_inode(struct sysfs_dirent *sd, struct inode *inode)
{
	struct bin_attribute *bin_attr;

	inode->i_private = sysfs_get(sd);
	inode->i_mapping->a_ops = &sysfs_aops;
	inode->i_mapping->backing_dev_info = &sysfs_backing_dev_info;
	inode->i_op = &sysfs_inode_operations;

	set_default_inode_attr(inode, sd->s_mode);
	sysfs_refresh_inode(sd, inode);

	/* initialize inode according to type */
	switch (sysfs_type(sd)) {
	case SYSFS_DIR:
		inode->i_op = &sysfs_dir_inode_operations;
		inode->i_fop = &sysfs_dir_operations;
		break;
	case SYSFS_KOBJ_ATTR:
		inode->i_size = PAGE_SIZE;
		inode->i_fop = &sysfs_file_operations;
		break;
	case SYSFS_KOBJ_BIN_ATTR:
		bin_attr = sd->s_bin_attr.bin_attr;
		inode->i_size = bin_attr->size;
		inode->i_fop = &bin_fops;
		break;
	case SYSFS_KOBJ_LINK:
		inode->i_op = &sysfs_symlink_inode_operations;
		break;
	default:
		BUG();
	}

	unlock_new_inode(inode);
}

/**
 *	sysfs_get_inode - get inode for sysfs_dirent
 *	@sb: super block
 *	@sd: sysfs_dirent to allocate inode for
 *
 *	Get inode for @sd.  If such inode doesn't exist, a new inode
 *	is allocated and basics are initialized.  New inode is
 *	returned locked.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 *
 *	RETURNS:
 *	Pointer to allocated inode on success, NULL on failure.
 */
struct inode * sysfs_get_inode(struct super_block *sb, struct sysfs_dirent *sd)
{
	struct inode *inode;

	inode = iget_locked(sb, sd->s_ino);
	if (inode && (inode->i_state & I_NEW))
		sysfs_init_inode(sd, inode);

	return inode;
}

/*
 * The sysfs_dirent serves as both an inode and a directory entry for sysfs.
 * To prevent the sysfs inode numbers from being freed prematurely we take a
 * reference to sysfs_dirent from the sysfs inode.  A
 * super_operations.delete_inode() implementation is needed to drop that
 * reference upon inode destruction.
 */
void sysfs_delete_inode(struct inode *inode)
{
	struct sysfs_dirent *sd  = inode->i_private;

	truncate_inode_pages(&inode->i_data, 0);
	clear_inode(inode);
	sysfs_put(sd);
}

int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const char *name)
{
	struct sysfs_addrm_cxt acxt;
	struct sysfs_dirent *sd;

	if (!dir_sd)
		return -ENOENT;

	sysfs_addrm_start(&acxt, dir_sd);

	sd = sysfs_find_dirent(dir_sd, name);
	if (sd)
		sysfs_remove_one(&acxt, sd);

	sysfs_addrm_finish(&acxt);

	if (sd)
		return 0;
	else
		return -ENOENT;
}

int sysfs_permission(struct inode *inode, int mask)
{
	struct sysfs_dirent *sd = inode->i_private;

	mutex_lock(&sysfs_mutex);
	sysfs_refresh_inode(sd, inode);
	mutex_unlock(&sysfs_mutex);

	return generic_permission(inode, mask, NULL);
}
Commit	Line	Data
1da177e4	1	/*
6d66f5cd	2	* fs/sysfs/inode.c - basic sysfs inode and dentry operations
1da177e4	3	*
6d66f5cd TH	4	* Copyright (c) 2001-3 Patrick Mochel
	5	* Copyright (c) 2007 SUSE Linux Products GmbH
	6	* Copyright (c) 2007 Tejun Heo <teheo@suse.de>
	7	*
	8	* This file is released under the GPLv2.
1da177e4 LT	9	*
	10	* Please see Documentation/filesystems/sysfs.txt for more information.
	11	*/
	12
	13	#undef DEBUG
	14
	15	#include <linux/pagemap.h>
	16	#include <linux/namei.h>
	17	#include <linux/backing-dev.h>
16f7e0fe	18	#include <linux/capability.h>
995982ca	19	#include <linux/errno.h>
e8edc6e0	20	#include <linux/sched.h>
ddd29ec6 DQ	21	#include <linux/xattr.h>
ddd29ec6 DQ	22	#include <linux/security.h>
1da177e4 LT	23	#include "sysfs.h"
	24
	25	extern struct super_block * sysfs_sb;
	26
f5e54d6e	27	static const struct address_space_operations sysfs_aops = {
1da177e4	28	.readpage = simple_readpage,
800d15a5 NP	29	.write_begin = simple_write_begin,
800d15a5 NP	30	.write_end = simple_write_end,
1da177e4 LT	31	};
	32
	33	static struct backing_dev_info sysfs_backing_dev_info = {
d993831f	34	.name = "sysfs",
1da177e4	35	.ra_pages = 0, /* No readahead */
e4ad08fe	36	.capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK,
1da177e4 LT	37	};
1da177e4 LT	38
c5ef1c42	39	static const struct inode_operations sysfs_inode_operations ={
e61ab4ae	40	.permission = sysfs_permission,
988d186d	41	.setattr = sysfs_setattr,
e61ab4ae	42	.getattr = sysfs_getattr,
ddd29ec6	43	.setxattr = sysfs_setxattr,
988d186d MS	44	};
988d186d MS	45
e0bf68dd PZ	46	int __init sysfs_inode_init(void)
	47	{
	48	return bdi_init(&sysfs_backing_dev_info);
	49	}
	50
f38506c4	51	static struct sysfs_inode_attrs sysfs_init_inode_attrs(struct sysfs_dirent sd)
ddd29ec6 DQ	52	{
	53	struct sysfs_inode_attrs *attrs;
	54	struct iattr *iattrs;
	55
	56	attrs = kzalloc(sizeof(struct sysfs_inode_attrs), GFP_KERNEL);
	57	if (!attrs)
	58	return NULL;
	59	iattrs = &attrs->ia_iattr;
	60
	61	/* assign default attributes */
	62	iattrs->ia_mode = sd->s_mode;
	63	iattrs->ia_uid = 0;
	64	iattrs->ia_gid = 0;
	65	iattrs->ia_atime = iattrs->ia_mtime = iattrs->ia_ctime = CURRENT_TIME;
	66
	67	return attrs;
	68	}
f38506c4	69
35df63c4	70	int sysfs_sd_setattr(struct sysfs_dirent sd, struct iattr iattr)
988d186d	71	{
ddd29ec6 DQ	72	struct sysfs_inode_attrs *sd_attrs;
ddd29ec6 DQ	73	struct iattr *iattrs;
988d186d	74	unsigned int ia_valid = iattr->ia_valid;
988d186d	75
ddd29ec6	76	sd_attrs = sd->s_iattr;
988d186d	77
ddd29ec6	78	if (!sd_attrs) {
988d186d	79	/* setting attributes for the first time, allocate now */
ddd29ec6 DQ	80	sd_attrs = sysfs_init_inode_attrs(sd);
ddd29ec6 DQ	81	if (!sd_attrs)
988d186d	82	return -ENOMEM;
ddd29ec6	83	sd->s_iattr = sd_attrs;
7c0ff870 EB	84	}
	85	/* attributes were changed at least once in past */
	86	iattrs = &sd_attrs->ia_iattr;
	87
	88	if (ia_valid & ATTR_UID)
	89	iattrs->ia_uid = iattr->ia_uid;
	90	if (ia_valid & ATTR_GID)
	91	iattrs->ia_gid = iattr->ia_gid;
	92	if (ia_valid & ATTR_ATIME)
	93	iattrs->ia_atime = iattr->ia_atime;
	94	if (ia_valid & ATTR_MTIME)
	95	iattrs->ia_mtime = iattr->ia_mtime;
	96	if (ia_valid & ATTR_CTIME)
	97	iattrs->ia_ctime = iattr->ia_ctime;
	98	if (ia_valid & ATTR_MODE) {
	99	umode_t mode = iattr->ia_mode;
	100	iattrs->ia_mode = sd->s_mode = mode;
988d186d	101	}
35df63c4 EB	102	return 0;
	103	}
	104
	105	int sysfs_setattr(struct dentry dentry, struct iattr iattr)
	106	{
	107	struct inode *inode = dentry->d_inode;
	108	struct sysfs_dirent *sd = dentry->d_fsdata;
	109	int error;
	110
	111	if (!sd)
	112	return -EINVAL;
	113
f8d4f618	114	mutex_lock(&sysfs_mutex);
35df63c4 EB	115	error = inode_change_ok(inode, iattr);
35df63c4 EB	116	if (error)
f8d4f618	117	goto out;
35df63c4 EB	118
35df63c4 EB	119	iattr->ia_valid &= ~ATTR_SIZE; /* ignore size changes */
35df63c4 EB	120
	121	error = inode_setattr(inode, iattr);
	122	if (error)
f8d4f618	123	goto out;
35df63c4	124
35df63c4	125	error = sysfs_sd_setattr(sd, iattr);
f8d4f618	126	out:
35df63c4	127	mutex_unlock(&sysfs_mutex);
ddd29ec6 DQ	128	return error;
ddd29ec6 DQ	129	}
988d186d	130
f44d3e78 EB	131	static int sysfs_sd_setsecdata(struct sysfs_dirent sd, void secdata, u32 secdata_len)
	132	{
	133	struct sysfs_inode_attrs *iattrs;
	134	void *old_secdata;
	135	size_t old_secdata_len;
	136
	137	iattrs = sd->s_iattr;
	138	if (!iattrs)
	139	iattrs = sysfs_init_inode_attrs(sd);
	140	if (!iattrs)
	141	return -ENOMEM;
	142
	143	old_secdata = iattrs->ia_secdata;
	144	old_secdata_len = iattrs->ia_secdata_len;
	145
	146	iattrs->ia_secdata = *secdata;
	147	iattrs->ia_secdata_len = *secdata_len;
	148
	149	*secdata = old_secdata;
	150	*secdata_len = old_secdata_len;
	151	return 0;
	152	}
	153
ddd29ec6 DQ	154	int sysfs_setxattr(struct dentry dentry, const char name, const void *value,
	155	size_t size, int flags)
	156	{
	157	struct sysfs_dirent *sd = dentry->d_fsdata;
ddd29ec6 DQ	158	void *secdata;
	159	int error;
	160	u32 secdata_len = 0;
	161
	162	if (!sd)
	163	return -EINVAL;
ddd29ec6 DQ	164
	165	if (!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN)) {
	166	const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
	167	error = security_inode_setsecurity(dentry->d_inode, suffix,
	168	value, size, flags);
	169	if (error)
	170	goto out;
	171	error = security_inode_getsecctx(dentry->d_inode,
	172	&secdata, &secdata_len);
	173	if (error)
	174	goto out;
988d186d	175
f44d3e78 EB	176	mutex_lock(&sysfs_mutex);
	177	error = sysfs_sd_setsecdata(sd, &secdata, &secdata_len);
	178	mutex_unlock(&sysfs_mutex);
	179
	180	if (secdata)
	181	security_release_secctx(secdata, secdata_len);
ddd29ec6 DQ	182	} else
	183	return -EINVAL;
	184	out:
988d186d MS	185	return error;
	186	}
	187
8215534c MS	188	static inline void set_default_inode_attr(struct inode * inode, mode_t mode)
	189	{
	190	inode->i_mode = mode;
8215534c MS	191	inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
	192	}
	193
	194	static inline void set_inode_attr(struct inode * inode, struct iattr * iattr)
	195	{
8215534c MS	196	inode->i_uid = iattr->ia_uid;
	197	inode->i_gid = iattr->ia_gid;
	198	inode->i_atime = iattr->ia_atime;
	199	inode->i_mtime = iattr->ia_mtime;
	200	inode->i_ctime = iattr->ia_ctime;
	201	}
	202
372e88bd EB	203	static int sysfs_count_nlink(struct sysfs_dirent *sd)
	204	{
	205	struct sysfs_dirent *child;
	206	int nr = 0;
	207
bc747f37	208	for (child = sd->s_dir.children; child; child = child->s_sibling)
372e88bd EB	209	if (sysfs_type(child) == SYSFS_DIR)
	210	nr++;
	211
	212	return nr + 2;
	213	}
	214
e61ab4ae EB	215	static void sysfs_refresh_inode(struct sysfs_dirent sd, struct inode inode)
	216	{
	217	struct sysfs_inode_attrs *iattrs = sd->s_iattr;
	218
	219	inode->i_mode = sd->s_mode;
	220	if (iattrs) {
	221	/* sysfs_dirent has non-default attributes
	222	* get them from persistent copy in sysfs_dirent
	223	*/
	224	set_inode_attr(inode, &iattrs->ia_iattr);
	225	security_inode_notifysecctx(inode,
	226	iattrs->ia_secdata,
	227	iattrs->ia_secdata_len);
	228	}
	229
	230	if (sysfs_type(sd) == SYSFS_DIR)
	231	inode->i_nlink = sysfs_count_nlink(sd);
	232	}
	233
	234	int sysfs_getattr(struct vfsmount mnt, struct dentry dentry, struct kstat *stat)
	235	{
	236	struct sysfs_dirent *sd = dentry->d_fsdata;
	237	struct inode *inode = dentry->d_inode;
	238
	239	mutex_lock(&sysfs_mutex);
	240	sysfs_refresh_inode(sd, inode);
	241	mutex_unlock(&sysfs_mutex);
	242
	243	generic_fillattr(inode, stat);
	244	return 0;
	245	}
	246
bc37e283	247	static void sysfs_init_inode(struct sysfs_dirent sd, struct inode inode)
1da177e4	248	{
372e88bd EB	249	struct bin_attribute *bin_attr;
372e88bd EB	250
04256b4a	251	inode->i_private = sysfs_get(sd);
fc9f54b9 TH	252	inode->i_mapping->a_ops = &sysfs_aops;
	253	inode->i_mapping->backing_dev_info = &sysfs_backing_dev_info;
	254	inode->i_op = &sysfs_inode_operations;
fc9f54b9	255
e61ab4ae EB	256	set_default_inode_attr(inode, sd->s_mode);
e61ab4ae EB	257	sysfs_refresh_inode(sd, inode);
372e88bd	258
372e88bd EB	259	/* initialize inode according to type */
372e88bd EB	260	switch (sysfs_type(sd)) {
372e88bd EB	261	case SYSFS_DIR:
	262	inode->i_op = &sysfs_dir_inode_operations;
	263	inode->i_fop = &sysfs_dir_operations;
372e88bd EB	264	break;
	265	case SYSFS_KOBJ_ATTR:
	266	inode->i_size = PAGE_SIZE;
	267	inode->i_fop = &sysfs_file_operations;
	268	break;
	269	case SYSFS_KOBJ_BIN_ATTR:
b1fc3d61	270	bin_attr = sd->s_bin_attr.bin_attr;
372e88bd EB	271	inode->i_size = bin_attr->size;
	272	inode->i_fop = &bin_fops;
	273	break;
	274	case SYSFS_KOBJ_LINK:
	275	inode->i_op = &sysfs_symlink_inode_operations;
	276	break;
	277	default:
	278	BUG();
	279	}
	280
	281	unlock_new_inode(inode);
fc9f54b9 TH	282	}
	283
	284	/**
8312a8d7	285	* sysfs_get_inode - get inode for sysfs_dirent
fac2622b	286	* @sb: super block
fc9f54b9 TH	287	* @sd: sysfs_dirent to allocate inode for
fc9f54b9 TH	288	*
8312a8d7 TH	289	* Get inode for @sd. If such inode doesn't exist, a new inode
	290	* is allocated and basics are initialized. New inode is
	291	* returned locked.
fc9f54b9 TH	292	*
	293	* LOCKING:
	294	* Kernel thread context (may sleep).
	295	*
	296	* RETURNS:
	297	* Pointer to allocated inode on success, NULL on failure.
	298	*/
fac2622b	299	struct inode * sysfs_get_inode(struct super_block sb, struct sysfs_dirent sd)
fc9f54b9 TH	300	{
	301	struct inode *inode;
	302
fac2622b	303	inode = iget_locked(sb, sd->s_ino);
8312a8d7	304	if (inode && (inode->i_state & I_NEW))
fc9f54b9 TH	305	sysfs_init_inode(sd, inode);
fc9f54b9 TH	306
1da177e4 LT	307	return inode;
	308	}
	309
04256b4a EB	310	/*
	311	* The sysfs_dirent serves as both an inode and a directory entry for sysfs.
	312	* To prevent the sysfs inode numbers from being freed prematurely we take a
	313	* reference to sysfs_dirent from the sysfs inode. A
	314	* super_operations.delete_inode() implementation is needed to drop that
	315	* reference upon inode destruction.
	316	*/
	317	void sysfs_delete_inode(struct inode *inode)
	318	{
	319	struct sysfs_dirent *sd = inode->i_private;
	320
	321	truncate_inode_pages(&inode->i_data, 0);
	322	clear_inode(inode);
	323	sysfs_put(sd);
	324	}
	325
608e266a	326	int sysfs_hash_and_remove(struct sysfs_dirent dir_sd, const char name)
1da177e4	327	{
fb6896da	328	struct sysfs_addrm_cxt acxt;
41fc1c27	329	struct sysfs_dirent *sd;
641e6f30	330
608e266a	331	if (!dir_sd)
995982ca	332	return -ENOENT;
1da177e4	333
fb6896da	334	sysfs_addrm_start(&acxt, dir_sd);
608e266a	335
41fc1c27 TH	336	sd = sysfs_find_dirent(dir_sd, name);
	337	if (sd)
	338	sysfs_remove_one(&acxt, sd);
3007e997	339
990e53f8 TH	340	sysfs_addrm_finish(&acxt);
	341
	342	if (sd)
fb6896da	343	return 0;
990e53f8 TH	344	else
990e53f8 TH	345	return -ENOENT;
1da177e4	346	}
e61ab4ae EB	347
	348	int sysfs_permission(struct inode *inode, int mask)
	349	{
	350	struct sysfs_dirent *sd = inode->i_private;
	351
	352	mutex_lock(&sysfs_mutex);
	353	sysfs_refresh_inode(sd, inode);
	354	mutex_unlock(&sysfs_mutex);
	355
	356	return generic_permission(inode, mask, NULL);
	357	}