summaryrefslogtreecommitdiff
path: root/fs/configfs/inode.c
blob: 42c348bb290394b80188d18142d6a0ebc943d866 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
// SPDX-License-Identifier: GPL-2.0-or-later
/* -*- mode: c; c-basic-offset: 8; -*-
 * vim: noexpandtab sw=8 ts=8 sts=0:
 *
 * inode.c - basic inode and dentry operations.
 *
 * Based on sysfs:
 * 	sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
 *
 * configfs Copyright (C) 2005 Oracle.  All rights reserved.
 *
 * Please see Documentation/filesystems/configfs.rst for more
 * information.
 */

#undef DEBUG

#include <linux/pagemap.h>
#include <linux/namei.h>
#include <linux/backing-dev.h>
#include <linux/capability.h>
#include <linux/sched.h>
#include <linux/lockdep.h>
#include <linux/slab.h>

#include <linux/configfs.h>
#include "configfs_internal.h"

#ifdef CONFIG_LOCKDEP
static struct lock_class_key default_group_class[MAX_LOCK_DEPTH];
#endif

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

static const struct inode_operations configfs_inode_operations ={
	.setattr	= configfs_setattr,
};

int configfs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
		     struct iattr *iattr)
{
	struct inode * inode = d_inode(dentry);
	struct configfs_dirent * sd = dentry->d_fsdata;
	struct iattr * sd_iattr;
	unsigned int ia_valid = iattr->ia_valid;
	int error;

	if (!sd)
		return -EINVAL;

	sd_iattr = sd->s_iattr;
	if (!sd_iattr) {
		/* setting attributes for the first time, allocate now */
		sd_iattr = kzalloc(sizeof(struct iattr), GFP_KERNEL);
		if (!sd_iattr)
			return -ENOMEM;
		/* assign default attributes */
		sd_iattr->ia_mode = sd->s_mode;
		sd_iattr->ia_uid = GLOBAL_ROOT_UID;
		sd_iattr->ia_gid = GLOBAL_ROOT_GID;
		sd_iattr->ia_atime = sd_iattr->ia_mtime =
			sd_iattr->ia_ctime = current_time(inode);
		sd->s_iattr = sd_iattr;
	}
	/* attributes were changed atleast once in past */

	error = simple_setattr(mnt_userns, dentry, iattr);
	if (error)
		return error;

	if (ia_valid & ATTR_UID)
		sd_iattr->ia_uid = iattr->ia_uid;
	if (ia_valid & ATTR_GID)
		sd_iattr->ia_gid = iattr->ia_gid;
	if (ia_valid & ATTR_ATIME)
		sd_iattr->ia_atime = iattr->ia_atime;
	if (ia_valid & ATTR_MTIME)
		sd_iattr->ia_mtime = iattr->ia_mtime;
	if (ia_valid & ATTR_CTIME)
		sd_iattr->ia_ctime = iattr->ia_ctime;
	if (ia_valid & ATTR_MODE) {
		umode_t mode = iattr->ia_mode;

		if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
			mode &= ~S_ISGID;
		sd_iattr->ia_mode = sd->s_mode = mode;
	}

	return error;
}

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(inode);
}

static inline void set_inode_attr(struct inode * inode, struct iattr * iattr)
{
	inode->i_mode = iattr->ia_mode;
	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;
}

struct inode *configfs_new_inode(umode_t mode, struct configfs_dirent *sd,
				 struct super_block *s)
{
	struct inode * inode = new_inode(s);
	if (inode) {
		inode->i_ino = get_next_ino();
		inode->i_mapping->a_ops = &configfs_aops;
		inode->i_op = &configfs_inode_operations;

		if (sd->s_iattr) {
			/* sysfs_dirent has non-default attributes
			 * get them for the new inode from persistent copy
			 * in sysfs_dirent
			 */
			set_inode_attr(inode, sd->s_iattr);
		} else
			set_default_inode_attr(inode, mode);
	}
	return inode;
}

#ifdef CONFIG_LOCKDEP

static void configfs_set_inode_lock_class(struct configfs_dirent *sd,
					  struct inode *inode)
{
	int depth = sd->s_depth;

	if (depth > 0) {
		if (depth <= ARRAY_SIZE(default_group_class)) {
			lockdep_set_class(&inode->i_rwsem,
					  &default_group_class[depth - 1]);
		} else {
			/*
			 * In practice the maximum level of locking depth is
			 * already reached. Just inform about possible reasons.
			 */
			pr_info("Too many levels of inodes for the locking correctness validator.\n");
			pr_info("Spurious warnings may appear.\n");
		}
	}
}

#else /* CONFIG_LOCKDEP */

static void configfs_set_inode_lock_class(struct configfs_dirent *sd,
					  struct inode *inode)
{
}

#endif /* CONFIG_LOCKDEP */

struct inode *configfs_create(struct dentry *dentry, umode_t mode)
{
	struct inode *inode = NULL;
	struct configfs_dirent *sd;
	struct inode *p_inode;

	if (!dentry)
		return ERR_PTR(-ENOENT);

	if (d_really_is_positive(dentry))
		return ERR_PTR(-EEXIST);

	sd = dentry->d_fsdata;
	inode = configfs_new_inode(mode, sd, dentry->d_sb);
	if (!inode)
		return ERR_PTR(-ENOMEM);

	p_inode = d_inode(dentry->d_parent);
	p_inode->i_mtime = p_inode->i_ctime = current_time(p_inode);
	configfs_set_inode_lock_class(sd, inode);
	return inode;
}

/*
 * Get the name for corresponding element represented by the given configfs_dirent
 */
const unsigned char * configfs_get_name(struct configfs_dirent *sd)
{
	struct configfs_attribute *attr;

	BUG_ON(!sd || !sd->s_element);

	/* These always have a dentry, so use that */
	if (sd->s_type & (CONFIGFS_DIR | CONFIGFS_ITEM_LINK))
		return sd->s_dentry->d_name.name;

	if (sd->s_type & (CONFIGFS_ITEM_ATTR | CONFIGFS_ITEM_BIN_ATTR)) {
		attr = sd->s_element;
		return attr->ca_name;
	}
	return NULL;
}


/*
 * Unhashes the dentry corresponding to given configfs_dirent
 * Called with parent inode's i_mutex held.
 */
void configfs_drop_dentry(struct configfs_dirent * sd, struct dentry * parent)
{
	struct dentry * dentry = sd->s_dentry;

	if (dentry) {
		spin_lock(&dentry->d_lock);
		if (simple_positive(dentry)) {
			dget_dlock(dentry);
			__d_drop(dentry);
			spin_unlock(&dentry->d_lock);
			simple_unlink(d_inode(parent), dentry);
		} else
			spin_unlock(&dentry->d_lock);
	}
}

void configfs_hash_and_remove(struct dentry * dir, const char * name)
{
	struct configfs_dirent * sd;
	struct configfs_dirent * parent_sd = dir->d_fsdata;

	if (d_really_is_negative(dir))
		/* no inode means this hasn't been made visible yet */
		return;

	inode_lock(d_inode(dir));
	list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
		if (!sd->s_element)
			continue;
		if (!strcmp(configfs_get_name(sd), name)) {
			spin_lock(&configfs_dirent_lock);
			list_del_init(&sd->s_sibling);
			spin_unlock(&configfs_dirent_lock);
			configfs_drop_dentry(sd, dir);
			configfs_put(sd);
			break;
		}
	}
	inode_unlock(d_inode(dir));
}