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

/*
 * fs/kernfs/inode.c - kernfs inode implementation
 *
 * Copyright (c) 2001-3 Patrick Mochel
 * Copyright (c) 2007 SUSE Linux Products GmbH
 * Copyright (c) 2007, 2013 Tejun Heo <[email protected]>
 *
 * This file is released under the GPLv2.
 */

#include <linux/pagemap.h>
#include <linux/backing-dev.h>
#include <linux/capability.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/xattr.h>
#include <linux/security.h>

#include "kernfs-internal.h"

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

static const struct inode_operations kernfs_iops = {
	.permission	= kernfs_iop_permission,
	.setattr	= kernfs_iop_setattr,
	.getattr	= kernfs_iop_getattr,
	.setxattr	= kernfs_iop_setxattr,
	.removexattr	= kernfs_iop_removexattr,
	.getxattr	= kernfs_iop_getxattr,
	.listxattr	= kernfs_iop_listxattr,
};

static struct kernfs_iattrs *kernfs_iattrs(struct kernfs_node *kn)
{
	static DEFINE_MUTEX(iattr_mutex);
	struct kernfs_iattrs *ret;
	struct iattr *iattrs;

	mutex_lock(&iattr_mutex);

	if (kn->iattr)
		goto out_unlock;

	kn->iattr = kzalloc(sizeof(struct kernfs_iattrs), GFP_KERNEL);
	if (!kn->iattr)
		goto out_unlock;
	iattrs = &kn->iattr->ia_iattr;

	/* assign default attributes */
	iattrs->ia_mode = kn->mode;
	iattrs->ia_uid = GLOBAL_ROOT_UID;
	iattrs->ia_gid = GLOBAL_ROOT_GID;
	iattrs->ia_atime = iattrs->ia_mtime = iattrs->ia_ctime = CURRENT_TIME;

	simple_xattrs_init(&kn->iattr->xattrs);
out_unlock:
	ret = kn->iattr;
	mutex_unlock(&iattr_mutex);
	return ret;
}

static int __kernfs_setattr(struct kernfs_node *kn, const struct iattr *iattr)
{
	struct kernfs_iattrs *attrs;
	struct iattr *iattrs;
	unsigned int ia_valid = iattr->ia_valid;

	attrs = kernfs_iattrs(kn);
	if (!attrs)
		return -ENOMEM;

	iattrs = &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 = kn->mode = mode;
	}
	return 0;
}

/**
 * kernfs_setattr - set iattr on a node
 * @kn: target node
 * @iattr: iattr to set
 *
 * Returns 0 on success, -errno on failure.
 */
int kernfs_setattr(struct kernfs_node *kn, const struct iattr *iattr)
{
	int ret;

	mutex_lock(&kernfs_mutex);
	ret = __kernfs_setattr(kn, iattr);
	mutex_unlock(&kernfs_mutex);
	return ret;
}

int kernfs_iop_setattr(struct dentry *dentry, struct iattr *iattr)
{
	struct inode *inode = d_inode(dentry);
	struct kernfs_node *kn = dentry->d_fsdata;
	int error;

	if (!kn)
		return -EINVAL;

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

	error = __kernfs_setattr(kn, iattr);
	if (error)
		goto out;

	/* this ignores size changes */
	setattr_copy(inode, iattr);

out:
	mutex_unlock(&kernfs_mutex);
	return error;
}

static int kernfs_node_setsecdata(struct kernfs_node *kn, void **secdata,
				  u32 *secdata_len)
{
	struct kernfs_iattrs *attrs;
	void *old_secdata;
	size_t old_secdata_len;

	attrs = kernfs_iattrs(kn);
	if (!attrs)
		return -ENOMEM;

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

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

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

int kernfs_iop_setxattr(struct dentry *dentry, const char *name,
			const void *value, size_t size, int flags)
{
	struct kernfs_node *kn = dentry->d_fsdata;
	struct kernfs_iattrs *attrs;
	void *secdata;
	int error;
	u32 secdata_len = 0;

	attrs = kernfs_iattrs(kn);
	if (!attrs)
		return -ENOMEM;

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

		mutex_lock(&kernfs_mutex);
		error = kernfs_node_setsecdata(kn, &secdata, &secdata_len);
		mutex_unlock(&kernfs_mutex);

		if (secdata)
			security_release_secctx(secdata, secdata_len);
		return error;
	} else if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN)) {
		return simple_xattr_set(&attrs->xattrs, name, value, size,
					flags);
	}

	return -EINVAL;
}

int kernfs_iop_removexattr(struct dentry *dentry, const char *name)
{
	struct kernfs_node *kn = dentry->d_fsdata;
	struct kernfs_iattrs *attrs;

	attrs = kernfs_iattrs(kn);
	if (!attrs)
		return -ENOMEM;

	return simple_xattr_remove(&attrs->xattrs, name);
}

ssize_t kernfs_iop_getxattr(struct dentry *dentry, const char *name, void *buf,
			    size_t size)
{
	struct kernfs_node *kn = dentry->d_fsdata;
	struct kernfs_iattrs *attrs;

	attrs = kernfs_iattrs(kn);
	if (!attrs)
		return -ENOMEM;

	return simple_xattr_get(&attrs->xattrs, name, buf, size);
}

ssize_t kernfs_iop_listxattr(struct dentry *dentry, char *buf, size_t size)
{
	struct kernfs_node *kn = dentry->d_fsdata;
	struct kernfs_iattrs *attrs;

	attrs = kernfs_iattrs(kn);
	if (!attrs)
		return -ENOMEM;

	return simple_xattr_list(&attrs->xattrs, buf, size);
}

static inline void set_default_inode_attr(struct inode *inode, umode_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 void kernfs_refresh_inode(struct kernfs_node *kn, struct inode *inode)
{
	struct kernfs_iattrs *attrs = kn->iattr;

	inode->i_mode = kn->mode;
	if (attrs) {
		/*
		 * kernfs_node has non-default attributes get them from
		 * persistent copy in kernfs_node.
		 */
		set_inode_attr(inode, &attrs->ia_iattr);
		security_inode_notifysecctx(inode, attrs->ia_secdata,
					    attrs->ia_secdata_len);
	}

	if (kernfs_type(kn) == KERNFS_DIR)
		set_nlink(inode, kn->dir.subdirs + 2);
}

int kernfs_iop_getattr(struct vfsmount *mnt, struct dentry *dentry,
		   struct kstat *stat)
{
	struct kernfs_node *kn = dentry->d_fsdata;
	struct inode *inode = d_inode(dentry);

	mutex_lock(&kernfs_mutex);
	kernfs_refresh_inode(kn, inode);
	mutex_unlock(&kernfs_mutex);

	generic_fillattr(inode, stat);
	return 0;
}

static void kernfs_init_inode(struct kernfs_node *kn, struct inode *inode)
{
	kernfs_get(kn);
	inode->i_private = kn;
	inode->i_mapping->a_ops = &kernfs_aops;
	inode->i_op = &kernfs_iops;

	set_default_inode_attr(inode, kn->mode);
	kernfs_refresh_inode(kn, inode);

	/* initialize inode according to type */
	switch (kernfs_type(kn)) {
	case KERNFS_DIR:
		inode->i_op = &kernfs_dir_iops;
		inode->i_fop = &kernfs_dir_fops;
		if (kn->flags & KERNFS_EMPTY_DIR)
			make_empty_dir_inode(inode);
		break;
	case KERNFS_FILE:
		inode->i_size = kn->attr.size;
		inode->i_fop = &kernfs_file_fops;
		break;
	case KERNFS_LINK:
		inode->i_op = &kernfs_symlink_iops;
		break;
	default:
		BUG();
	}

	unlock_new_inode(inode);
}

/**
 *	kernfs_get_inode - get inode for kernfs_node
 *	@sb: super block
 *	@kn: kernfs_node to allocate inode for
 *
 *	Get inode for @kn.  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 *kernfs_get_inode(struct super_block *sb, struct kernfs_node *kn)
{
	struct inode *inode;

	inode = iget_locked(sb, kn->ino);
	if (inode && (inode->i_state & I_NEW))
		kernfs_init_inode(kn, inode);

	return inode;
}

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

	truncate_inode_pages_final(&inode->i_data);
	clear_inode(inode);
	kernfs_put(kn);
}

int kernfs_iop_permission(struct inode *inode, int mask)
{
	struct kernfs_node *kn;

	if (mask & MAY_NOT_BLOCK)
		return -ECHILD;

	kn = inode->i_private;

	mutex_lock(&kernfs_mutex);
	kernfs_refresh_inode(kn, inode);
	mutex_unlock(&kernfs_mutex);

	return generic_permission(inode, mask);
}
Commit	Line	Data
b8441ed2 TH	1	/*
	2	* fs/kernfs/inode.c - kernfs inode implementation
	3	*
	4	* Copyright (c) 2001-3 Patrick Mochel
	5	* Copyright (c) 2007 SUSE Linux Products GmbH
	6	* Copyright (c) 2007, 2013 Tejun Heo <[email protected]>
	7	*
	8	* This file is released under the GPLv2.
	9	*/
ffed24e2 TH	10
	11	#include <linux/pagemap.h>
	12	#include <linux/backing-dev.h>
	13	#include <linux/capability.h>
	14	#include <linux/errno.h>
	15	#include <linux/slab.h>
	16	#include <linux/xattr.h>
	17	#include <linux/security.h>
	18
	19	#include "kernfs-internal.h"
	20
a797bfc3	21	static const struct address_space_operations kernfs_aops = {
ffed24e2 TH	22	.readpage = simple_readpage,
	23	.write_begin = simple_write_begin,
	24	.write_end = simple_write_end,
	25	};
	26
a797bfc3	27	static const struct inode_operations kernfs_iops = {
c637b8ac TH	28	.permission = kernfs_iop_permission,
	29	.setattr = kernfs_iop_setattr,
	30	.getattr = kernfs_iop_getattr,
	31	.setxattr = kernfs_iop_setxattr,
	32	.removexattr = kernfs_iop_removexattr,
	33	.getxattr = kernfs_iop_getxattr,
	34	.listxattr = kernfs_iop_listxattr,
ffed24e2 TH	35	};
ffed24e2 TH	36
c525aadd	37	static struct kernfs_iattrs kernfs_iattrs(struct kernfs_node kn)
ffed24e2	38	{
4afddd60 TH	39	static DEFINE_MUTEX(iattr_mutex);
4afddd60 TH	40	struct kernfs_iattrs *ret;
ffed24e2 TH	41	struct iattr *iattrs;
ffed24e2 TH	42
4afddd60 TH	43	mutex_lock(&iattr_mutex);
4afddd60 TH	44
adc5e8b5	45	if (kn->iattr)
4afddd60	46	goto out_unlock;
9a8049af	47
c525aadd	48	kn->iattr = kzalloc(sizeof(struct kernfs_iattrs), GFP_KERNEL);
adc5e8b5	49	if (!kn->iattr)
4afddd60	50	goto out_unlock;
adc5e8b5	51	iattrs = &kn->iattr->ia_iattr;
ffed24e2 TH	52
ffed24e2 TH	53	/* assign default attributes */
adc5e8b5	54	iattrs->ia_mode = kn->mode;
ffed24e2 TH	55	iattrs->ia_uid = GLOBAL_ROOT_UID;
	56	iattrs->ia_gid = GLOBAL_ROOT_GID;
	57	iattrs->ia_atime = iattrs->ia_mtime = iattrs->ia_ctime = CURRENT_TIME;
	58
adc5e8b5	59	simple_xattrs_init(&kn->iattr->xattrs);
4afddd60 TH	60	out_unlock:
	61	ret = kn->iattr;
	62	mutex_unlock(&iattr_mutex);
	63	return ret;
ffed24e2 TH	64	}
ffed24e2 TH	65
324a56e1	66	static int __kernfs_setattr(struct kernfs_node kn, const struct iattr iattr)
ffed24e2	67	{
c525aadd	68	struct kernfs_iattrs *attrs;
ffed24e2 TH	69	struct iattr *iattrs;
	70	unsigned int ia_valid = iattr->ia_valid;
	71
c525aadd	72	attrs = kernfs_iattrs(kn);
9a8049af TH	73	if (!attrs)
9a8049af TH	74	return -ENOMEM;
ffed24e2	75
9a8049af	76	iattrs = &attrs->ia_iattr;
ffed24e2 TH	77
	78	if (ia_valid & ATTR_UID)
	79	iattrs->ia_uid = iattr->ia_uid;
	80	if (ia_valid & ATTR_GID)
	81	iattrs->ia_gid = iattr->ia_gid;
	82	if (ia_valid & ATTR_ATIME)
	83	iattrs->ia_atime = iattr->ia_atime;
	84	if (ia_valid & ATTR_MTIME)
	85	iattrs->ia_mtime = iattr->ia_mtime;
	86	if (ia_valid & ATTR_CTIME)
	87	iattrs->ia_ctime = iattr->ia_ctime;
	88	if (ia_valid & ATTR_MODE) {
	89	umode_t mode = iattr->ia_mode;
adc5e8b5	90	iattrs->ia_mode = kn->mode = mode;
ffed24e2 TH	91	}
	92	return 0;
	93	}
	94
	95	/**
	96	* kernfs_setattr - set iattr on a node
324a56e1	97	* @kn: target node
ffed24e2 TH	98	* @iattr: iattr to set
	99	*
	100	* Returns 0 on success, -errno on failure.
	101	*/
324a56e1	102	int kernfs_setattr(struct kernfs_node kn, const struct iattr iattr)
ffed24e2 TH	103	{
	104	int ret;
	105
a797bfc3	106	mutex_lock(&kernfs_mutex);
324a56e1	107	ret = __kernfs_setattr(kn, iattr);
a797bfc3	108	mutex_unlock(&kernfs_mutex);
ffed24e2 TH	109	return ret;
	110	}
	111
c637b8ac	112	int kernfs_iop_setattr(struct dentry dentry, struct iattr iattr)
ffed24e2	113	{
2b0143b5	114	struct inode *inode = d_inode(dentry);
324a56e1	115	struct kernfs_node *kn = dentry->d_fsdata;
ffed24e2 TH	116	int error;
ffed24e2 TH	117
324a56e1	118	if (!kn)
ffed24e2 TH	119	return -EINVAL;
ffed24e2 TH	120
a797bfc3	121	mutex_lock(&kernfs_mutex);
ffed24e2 TH	122	error = inode_change_ok(inode, iattr);
	123	if (error)
	124	goto out;
	125
324a56e1	126	error = __kernfs_setattr(kn, iattr);
ffed24e2 TH	127	if (error)
	128	goto out;
	129
	130	/* this ignores size changes */
	131	setattr_copy(inode, iattr);
	132
	133	out:
a797bfc3	134	mutex_unlock(&kernfs_mutex);
ffed24e2 TH	135	return error;
	136	}
	137
c637b8ac TH	138	static int kernfs_node_setsecdata(struct kernfs_node kn, void *secdata,
c637b8ac TH	139	u32 *secdata_len)
ffed24e2	140	{
c525aadd	141	struct kernfs_iattrs *attrs;
ffed24e2 TH	142	void *old_secdata;
	143	size_t old_secdata_len;
	144
c525aadd	145	attrs = kernfs_iattrs(kn);
9a8049af TH	146	if (!attrs)
9a8049af TH	147	return -ENOMEM;
ffed24e2	148
9a8049af TH	149	old_secdata = attrs->ia_secdata;
9a8049af TH	150	old_secdata_len = attrs->ia_secdata_len;
ffed24e2	151
9a8049af TH	152	attrs->ia_secdata = *secdata;
9a8049af TH	153	attrs->ia_secdata_len = *secdata_len;
ffed24e2 TH	154
	155	*secdata = old_secdata;
	156	*secdata_len = old_secdata_len;
	157	return 0;
	158	}
	159
c637b8ac TH	160	int kernfs_iop_setxattr(struct dentry dentry, const char name,
c637b8ac TH	161	const void *value, size_t size, int flags)
ffed24e2	162	{
324a56e1	163	struct kernfs_node *kn = dentry->d_fsdata;
c525aadd	164	struct kernfs_iattrs *attrs;
ffed24e2 TH	165	void *secdata;
	166	int error;
	167	u32 secdata_len = 0;
	168
c525aadd	169	attrs = kernfs_iattrs(kn);
2322392b TH	170	if (!attrs)
2322392b TH	171	return -ENOMEM;
ffed24e2 TH	172
	173	if (!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN)) {
	174	const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
2b0143b5	175	error = security_inode_setsecurity(d_inode(dentry), suffix,
ffed24e2 TH	176	value, size, flags);
ffed24e2 TH	177	if (error)
2322392b	178	return error;
2b0143b5	179	error = security_inode_getsecctx(d_inode(dentry),
ffed24e2 TH	180	&secdata, &secdata_len);
ffed24e2 TH	181	if (error)
2322392b	182	return error;
ffed24e2	183
a797bfc3	184	mutex_lock(&kernfs_mutex);
c637b8ac	185	error = kernfs_node_setsecdata(kn, &secdata, &secdata_len);
a797bfc3	186	mutex_unlock(&kernfs_mutex);
ffed24e2 TH	187
	188	if (secdata)
	189	security_release_secctx(secdata, secdata_len);
2322392b TH	190	return error;
	191	} else if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN)) {
	192	return simple_xattr_set(&attrs->xattrs, name, value, size,
	193	flags);
	194	}
	195
	196	return -EINVAL;
	197	}
	198
c637b8ac	199	int kernfs_iop_removexattr(struct dentry dentry, const char name)
2322392b	200	{
324a56e1	201	struct kernfs_node *kn = dentry->d_fsdata;
c525aadd	202	struct kernfs_iattrs *attrs;
2322392b	203
c525aadd	204	attrs = kernfs_iattrs(kn);
2322392b TH	205	if (!attrs)
	206	return -ENOMEM;
	207
	208	return simple_xattr_remove(&attrs->xattrs, name);
	209	}
	210
c637b8ac TH	211	ssize_t kernfs_iop_getxattr(struct dentry dentry, const char name, void *buf,
c637b8ac TH	212	size_t size)
2322392b	213	{
324a56e1	214	struct kernfs_node *kn = dentry->d_fsdata;
c525aadd	215	struct kernfs_iattrs *attrs;
2322392b	216
c525aadd	217	attrs = kernfs_iattrs(kn);
2322392b TH	218	if (!attrs)
	219	return -ENOMEM;
	220
	221	return simple_xattr_get(&attrs->xattrs, name, buf, size);
	222	}
	223
c637b8ac	224	ssize_t kernfs_iop_listxattr(struct dentry dentry, char buf, size_t size)
2322392b	225	{
324a56e1	226	struct kernfs_node *kn = dentry->d_fsdata;
c525aadd	227	struct kernfs_iattrs *attrs;
2322392b	228
c525aadd	229	attrs = kernfs_iattrs(kn);
2322392b TH	230	if (!attrs)
	231	return -ENOMEM;
	232
	233	return simple_xattr_list(&attrs->xattrs, buf, size);
ffed24e2 TH	234	}
	235
	236	static inline void set_default_inode_attr(struct inode *inode, umode_t mode)
	237	{
	238	inode->i_mode = mode;
	239	inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
	240	}
	241
	242	static inline void set_inode_attr(struct inode inode, struct iattr iattr)
	243	{
	244	inode->i_uid = iattr->ia_uid;
	245	inode->i_gid = iattr->ia_gid;
	246	inode->i_atime = iattr->ia_atime;
	247	inode->i_mtime = iattr->ia_mtime;
	248	inode->i_ctime = iattr->ia_ctime;
	249	}
	250
c637b8ac	251	static void kernfs_refresh_inode(struct kernfs_node kn, struct inode inode)
ffed24e2	252	{
c525aadd	253	struct kernfs_iattrs *attrs = kn->iattr;
ffed24e2	254
adc5e8b5	255	inode->i_mode = kn->mode;
9a8049af	256	if (attrs) {
324a56e1 TH	257	/*
	258	* kernfs_node has non-default attributes get them from
	259	* persistent copy in kernfs_node.
ffed24e2	260	*/
9a8049af TH	261	set_inode_attr(inode, &attrs->ia_iattr);
	262	security_inode_notifysecctx(inode, attrs->ia_secdata,
	263	attrs->ia_secdata_len);
ffed24e2 TH	264	}
ffed24e2 TH	265
df23fc39	266	if (kernfs_type(kn) == KERNFS_DIR)
adc5e8b5	267	set_nlink(inode, kn->dir.subdirs + 2);
ffed24e2 TH	268	}
ffed24e2 TH	269
c637b8ac TH	270	int kernfs_iop_getattr(struct vfsmount mnt, struct dentry dentry,
c637b8ac TH	271	struct kstat *stat)
ffed24e2	272	{
324a56e1	273	struct kernfs_node *kn = dentry->d_fsdata;
2b0143b5	274	struct inode *inode = d_inode(dentry);
ffed24e2	275
a797bfc3	276	mutex_lock(&kernfs_mutex);
c637b8ac	277	kernfs_refresh_inode(kn, inode);
a797bfc3	278	mutex_unlock(&kernfs_mutex);
ffed24e2 TH	279
	280	generic_fillattr(inode, stat);
	281	return 0;
	282	}
	283
c637b8ac	284	static void kernfs_init_inode(struct kernfs_node kn, struct inode inode)
ffed24e2	285	{
324a56e1 TH	286	kernfs_get(kn);
324a56e1 TH	287	inode->i_private = kn;
a797bfc3	288	inode->i_mapping->a_ops = &kernfs_aops;
a797bfc3	289	inode->i_op = &kernfs_iops;
ffed24e2	290
adc5e8b5	291	set_default_inode_attr(inode, kn->mode);
c637b8ac	292	kernfs_refresh_inode(kn, inode);
ffed24e2 TH	293
ffed24e2 TH	294	/* initialize inode according to type */
df23fc39 TH	295	switch (kernfs_type(kn)) {
df23fc39 TH	296	case KERNFS_DIR:
a797bfc3 TH	297	inode->i_op = &kernfs_dir_iops;
a797bfc3 TH	298	inode->i_fop = &kernfs_dir_fops;
ea015218 EB	299	if (kn->flags & KERNFS_EMPTY_DIR)
ea015218 EB	300	make_empty_dir_inode(inode);
ffed24e2	301	break;
df23fc39	302	case KERNFS_FILE:
adc5e8b5	303	inode->i_size = kn->attr.size;
a797bfc3	304	inode->i_fop = &kernfs_file_fops;
ffed24e2	305	break;
df23fc39	306	case KERNFS_LINK:
a797bfc3	307	inode->i_op = &kernfs_symlink_iops;
ffed24e2 TH	308	break;
	309	default:
	310	BUG();
	311	}
	312
	313	unlock_new_inode(inode);
	314	}
	315
	316	/**
c637b8ac	317	* kernfs_get_inode - get inode for kernfs_node
ffed24e2	318	* @sb: super block
324a56e1	319	* @kn: kernfs_node to allocate inode for
ffed24e2	320	*
324a56e1 TH	321	* Get inode for @kn. If such inode doesn't exist, a new inode is
	322	* allocated and basics are initialized. New inode is returned
	323	* locked.
ffed24e2 TH	324	*
	325	* LOCKING:
	326	* Kernel thread context (may sleep).
	327	*
	328	* RETURNS:
	329	* Pointer to allocated inode on success, NULL on failure.
	330	*/
c637b8ac	331	struct inode kernfs_get_inode(struct super_block sb, struct kernfs_node *kn)
ffed24e2 TH	332	{
	333	struct inode *inode;
	334
adc5e8b5	335	inode = iget_locked(sb, kn->ino);
ffed24e2	336	if (inode && (inode->i_state & I_NEW))
c637b8ac	337	kernfs_init_inode(kn, inode);
ffed24e2 TH	338
	339	return inode;
	340	}
	341
	342	/*
c637b8ac TH	343	* The kernfs_node serves as both an inode and a directory entry for
	344	* kernfs. To prevent the kernfs inode numbers from being freed
	345	* prematurely we take a reference to kernfs_node from the kernfs inode. A
ffed24e2 TH	346	* super_operations.evict_inode() implementation is needed to drop that
	347	* reference upon inode destruction.
	348	*/
c637b8ac	349	void kernfs_evict_inode(struct inode *inode)
ffed24e2	350	{
324a56e1	351	struct kernfs_node *kn = inode->i_private;
ffed24e2	352
91b0abe3	353	truncate_inode_pages_final(&inode->i_data);
ffed24e2	354	clear_inode(inode);
324a56e1	355	kernfs_put(kn);
ffed24e2 TH	356	}
ffed24e2 TH	357
c637b8ac	358	int kernfs_iop_permission(struct inode *inode, int mask)
ffed24e2	359	{
324a56e1	360	struct kernfs_node *kn;
ffed24e2 TH	361
	362	if (mask & MAY_NOT_BLOCK)
	363	return -ECHILD;
	364
324a56e1	365	kn = inode->i_private;
ffed24e2	366
a797bfc3	367	mutex_lock(&kernfs_mutex);
c637b8ac	368	kernfs_refresh_inode(kn, inode);
a797bfc3	369	mutex_unlock(&kernfs_mutex);
ffed24e2 TH	370
	371	return generic_permission(inode, mask);
	372	}