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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * inode.c - basic inode and dentry operations.
4 *
5 * Based on sysfs:
6 * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
7 *
8 * configfs Copyright (C) 2005 Oracle. All rights reserved.
9 *
10 * Please see Documentation/filesystems/configfs.rst for more
11 * information.
12 */
13
14#undef DEBUG
15
16#include <linux/pagemap.h>
17#include <linux/namei.h>
18#include <linux/backing-dev.h>
19#include <linux/capability.h>
20#include <linux/sched.h>
21#include <linux/lockdep.h>
22#include <linux/slab.h>
23
24#include <linux/configfs.h>
25#include "configfs_internal.h"
26
27#ifdef CONFIG_LOCKDEP
28static struct lock_class_key default_group_class[MAX_LOCK_DEPTH];
29#endif
30
31static const struct inode_operations configfs_inode_operations ={
32 .setattr = configfs_setattr,
33};
34
35int configfs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
36 struct iattr *iattr)
37{
38 struct inode * inode = d_inode(dentry);
39 struct configfs_dirent * sd = dentry->d_fsdata;
40 struct iattr * sd_iattr;
41 unsigned int ia_valid = iattr->ia_valid;
42 int error;
43
44 if (!sd)
45 return -EINVAL;
46
47 sd_iattr = sd->s_iattr;
48 if (!sd_iattr) {
49 /* setting attributes for the first time, allocate now */
50 sd_iattr = kzalloc(sizeof(struct iattr), GFP_KERNEL);
51 if (!sd_iattr)
52 return -ENOMEM;
53 /* assign default attributes */
54 sd_iattr->ia_mode = sd->s_mode;
55 sd_iattr->ia_uid = GLOBAL_ROOT_UID;
56 sd_iattr->ia_gid = GLOBAL_ROOT_GID;
57 sd_iattr->ia_atime = sd_iattr->ia_mtime =
58 sd_iattr->ia_ctime = current_time(inode);
59 sd->s_iattr = sd_iattr;
60 }
61 /* attributes were changed atleast once in past */
62
63 error = simple_setattr(mnt_userns, dentry, iattr);
64 if (error)
65 return error;
66
67 if (ia_valid & ATTR_UID)
68 sd_iattr->ia_uid = iattr->ia_uid;
69 if (ia_valid & ATTR_GID)
70 sd_iattr->ia_gid = iattr->ia_gid;
71 if (ia_valid & ATTR_ATIME)
72 sd_iattr->ia_atime = iattr->ia_atime;
73 if (ia_valid & ATTR_MTIME)
74 sd_iattr->ia_mtime = iattr->ia_mtime;
75 if (ia_valid & ATTR_CTIME)
76 sd_iattr->ia_ctime = iattr->ia_ctime;
77 if (ia_valid & ATTR_MODE) {
78 umode_t mode = iattr->ia_mode;
79
80 if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
81 mode &= ~S_ISGID;
82 sd_iattr->ia_mode = sd->s_mode = mode;
83 }
84
85 return error;
86}
87
88static inline void set_default_inode_attr(struct inode * inode, umode_t mode)
89{
90 inode->i_mode = mode;
91 inode->i_atime = inode->i_mtime =
92 inode->i_ctime = current_time(inode);
93}
94
95static inline void set_inode_attr(struct inode * inode, struct iattr * iattr)
96{
97 inode->i_mode = iattr->ia_mode;
98 inode->i_uid = iattr->ia_uid;
99 inode->i_gid = iattr->ia_gid;
100 inode->i_atime = iattr->ia_atime;
101 inode->i_mtime = iattr->ia_mtime;
102 inode->i_ctime = iattr->ia_ctime;
103}
104
105struct inode *configfs_new_inode(umode_t mode, struct configfs_dirent *sd,
106 struct super_block *s)
107{
108 struct inode * inode = new_inode(s);
109 if (inode) {
110 inode->i_ino = get_next_ino();
111 inode->i_mapping->a_ops = &ram_aops;
112 inode->i_op = &configfs_inode_operations;
113
114 if (sd->s_iattr) {
115 /* sysfs_dirent has non-default attributes
116 * get them for the new inode from persistent copy
117 * in sysfs_dirent
118 */
119 set_inode_attr(inode, sd->s_iattr);
120 } else
121 set_default_inode_attr(inode, mode);
122 }
123 return inode;
124}
125
126#ifdef CONFIG_LOCKDEP
127
128static void configfs_set_inode_lock_class(struct configfs_dirent *sd,
129 struct inode *inode)
130{
131 int depth = sd->s_depth;
132
133 if (depth > 0) {
134 if (depth <= ARRAY_SIZE(default_group_class)) {
135 lockdep_set_class(&inode->i_rwsem,
136 &default_group_class[depth - 1]);
137 } else {
138 /*
139 * In practice the maximum level of locking depth is
140 * already reached. Just inform about possible reasons.
141 */
142 pr_info("Too many levels of inodes for the locking correctness validator.\n");
143 pr_info("Spurious warnings may appear.\n");
144 }
145 }
146}
147
148#else /* CONFIG_LOCKDEP */
149
150static void configfs_set_inode_lock_class(struct configfs_dirent *sd,
151 struct inode *inode)
152{
153}
154
155#endif /* CONFIG_LOCKDEP */
156
157struct inode *configfs_create(struct dentry *dentry, umode_t mode)
158{
159 struct inode *inode = NULL;
160 struct configfs_dirent *sd;
161 struct inode *p_inode;
162
163 if (!dentry)
164 return ERR_PTR(-ENOENT);
165
166 if (d_really_is_positive(dentry))
167 return ERR_PTR(-EEXIST);
168
169 sd = dentry->d_fsdata;
170 inode = configfs_new_inode(mode, sd, dentry->d_sb);
171 if (!inode)
172 return ERR_PTR(-ENOMEM);
173
174 p_inode = d_inode(dentry->d_parent);
175 p_inode->i_mtime = p_inode->i_ctime = current_time(p_inode);
176 configfs_set_inode_lock_class(sd, inode);
177 return inode;
178}
179
180/*
181 * Get the name for corresponding element represented by the given configfs_dirent
182 */
183const unsigned char * configfs_get_name(struct configfs_dirent *sd)
184{
185 struct configfs_attribute *attr;
186
187 BUG_ON(!sd || !sd->s_element);
188
189 /* These always have a dentry, so use that */
190 if (sd->s_type & (CONFIGFS_DIR | CONFIGFS_ITEM_LINK))
191 return sd->s_dentry->d_name.name;
192
193 if (sd->s_type & (CONFIGFS_ITEM_ATTR | CONFIGFS_ITEM_BIN_ATTR)) {
194 attr = sd->s_element;
195 return attr->ca_name;
196 }
197 return NULL;
198}
199
200
201/*
202 * Unhashes the dentry corresponding to given configfs_dirent
203 * Called with parent inode's i_mutex held.
204 */
205void configfs_drop_dentry(struct configfs_dirent * sd, struct dentry * parent)
206{
207 struct dentry * dentry = sd->s_dentry;
208
209 if (dentry) {
210 spin_lock(&dentry->d_lock);
211 if (simple_positive(dentry)) {
212 dget_dlock(dentry);
213 __d_drop(dentry);
214 spin_unlock(&dentry->d_lock);
215 simple_unlink(d_inode(parent), dentry);
216 } else
217 spin_unlock(&dentry->d_lock);
218 }
219}
220
221void configfs_hash_and_remove(struct dentry * dir, const char * name)
222{
223 struct configfs_dirent * sd;
224 struct configfs_dirent * parent_sd = dir->d_fsdata;
225
226 if (d_really_is_negative(dir))
227 /* no inode means this hasn't been made visible yet */
228 return;
229
230 inode_lock(d_inode(dir));
231 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
232 if (!sd->s_element)
233 continue;
234 if (!strcmp(configfs_get_name(sd), name)) {
235 spin_lock(&configfs_dirent_lock);
236 list_del_init(&sd->s_sibling);
237 spin_unlock(&configfs_dirent_lock);
238 configfs_drop_dentry(sd, dir);
239 configfs_put(sd);
240 break;
241 }
242 }
243 inode_unlock(d_inode(dir));
244}
1/* -*- mode: c; c-basic-offset: 8; -*-
2 * vim: noexpandtab sw=8 ts=8 sts=0:
3 *
4 * inode.c - basic inode and dentry operations.
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public
8 * License as published by the Free Software Foundation; either
9 * version 2 of the License, or (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public
17 * License along with this program; if not, write to the
18 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
19 * Boston, MA 021110-1307, USA.
20 *
21 * Based on sysfs:
22 * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
23 *
24 * configfs Copyright (C) 2005 Oracle. All rights reserved.
25 *
26 * Please see Documentation/filesystems/configfs.txt for more information.
27 */
28
29#undef DEBUG
30
31#include <linux/pagemap.h>
32#include <linux/namei.h>
33#include <linux/backing-dev.h>
34#include <linux/capability.h>
35#include <linux/sched.h>
36#include <linux/lockdep.h>
37#include <linux/slab.h>
38
39#include <linux/configfs.h>
40#include "configfs_internal.h"
41
42#ifdef CONFIG_LOCKDEP
43static struct lock_class_key default_group_class[MAX_LOCK_DEPTH];
44#endif
45
46extern struct super_block * configfs_sb;
47
48static const struct address_space_operations configfs_aops = {
49 .readpage = simple_readpage,
50 .write_begin = simple_write_begin,
51 .write_end = simple_write_end,
52};
53
54static struct backing_dev_info configfs_backing_dev_info = {
55 .name = "configfs",
56 .ra_pages = 0, /* No readahead */
57 .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK,
58};
59
60static const struct inode_operations configfs_inode_operations ={
61 .setattr = configfs_setattr,
62};
63
64int configfs_setattr(struct dentry * dentry, struct iattr * iattr)
65{
66 struct inode * inode = dentry->d_inode;
67 struct configfs_dirent * sd = dentry->d_fsdata;
68 struct iattr * sd_iattr;
69 unsigned int ia_valid = iattr->ia_valid;
70 int error;
71
72 if (!sd)
73 return -EINVAL;
74
75 sd_iattr = sd->s_iattr;
76 if (!sd_iattr) {
77 /* setting attributes for the first time, allocate now */
78 sd_iattr = kzalloc(sizeof(struct iattr), GFP_KERNEL);
79 if (!sd_iattr)
80 return -ENOMEM;
81 /* assign default attributes */
82 sd_iattr->ia_mode = sd->s_mode;
83 sd_iattr->ia_uid = 0;
84 sd_iattr->ia_gid = 0;
85 sd_iattr->ia_atime = sd_iattr->ia_mtime = sd_iattr->ia_ctime = CURRENT_TIME;
86 sd->s_iattr = sd_iattr;
87 }
88 /* attributes were changed atleast once in past */
89
90 error = simple_setattr(dentry, iattr);
91 if (error)
92 return error;
93
94 if (ia_valid & ATTR_UID)
95 sd_iattr->ia_uid = iattr->ia_uid;
96 if (ia_valid & ATTR_GID)
97 sd_iattr->ia_gid = iattr->ia_gid;
98 if (ia_valid & ATTR_ATIME)
99 sd_iattr->ia_atime = timespec_trunc(iattr->ia_atime,
100 inode->i_sb->s_time_gran);
101 if (ia_valid & ATTR_MTIME)
102 sd_iattr->ia_mtime = timespec_trunc(iattr->ia_mtime,
103 inode->i_sb->s_time_gran);
104 if (ia_valid & ATTR_CTIME)
105 sd_iattr->ia_ctime = timespec_trunc(iattr->ia_ctime,
106 inode->i_sb->s_time_gran);
107 if (ia_valid & ATTR_MODE) {
108 umode_t mode = iattr->ia_mode;
109
110 if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
111 mode &= ~S_ISGID;
112 sd_iattr->ia_mode = sd->s_mode = mode;
113 }
114
115 return error;
116}
117
118static inline void set_default_inode_attr(struct inode * inode, mode_t mode)
119{
120 inode->i_mode = mode;
121 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
122}
123
124static inline void set_inode_attr(struct inode * inode, struct iattr * iattr)
125{
126 inode->i_mode = iattr->ia_mode;
127 inode->i_uid = iattr->ia_uid;
128 inode->i_gid = iattr->ia_gid;
129 inode->i_atime = iattr->ia_atime;
130 inode->i_mtime = iattr->ia_mtime;
131 inode->i_ctime = iattr->ia_ctime;
132}
133
134struct inode * configfs_new_inode(mode_t mode, struct configfs_dirent * sd)
135{
136 struct inode * inode = new_inode(configfs_sb);
137 if (inode) {
138 inode->i_ino = get_next_ino();
139 inode->i_mapping->a_ops = &configfs_aops;
140 inode->i_mapping->backing_dev_info = &configfs_backing_dev_info;
141 inode->i_op = &configfs_inode_operations;
142
143 if (sd->s_iattr) {
144 /* sysfs_dirent has non-default attributes
145 * get them for the new inode from persistent copy
146 * in sysfs_dirent
147 */
148 set_inode_attr(inode, sd->s_iattr);
149 } else
150 set_default_inode_attr(inode, mode);
151 }
152 return inode;
153}
154
155#ifdef CONFIG_LOCKDEP
156
157static void configfs_set_inode_lock_class(struct configfs_dirent *sd,
158 struct inode *inode)
159{
160 int depth = sd->s_depth;
161
162 if (depth > 0) {
163 if (depth <= ARRAY_SIZE(default_group_class)) {
164 lockdep_set_class(&inode->i_mutex,
165 &default_group_class[depth - 1]);
166 } else {
167 /*
168 * In practice the maximum level of locking depth is
169 * already reached. Just inform about possible reasons.
170 */
171 printk(KERN_INFO "configfs: Too many levels of inodes"
172 " for the locking correctness validator.\n");
173 printk(KERN_INFO "Spurious warnings may appear.\n");
174 }
175 }
176}
177
178#else /* CONFIG_LOCKDEP */
179
180static void configfs_set_inode_lock_class(struct configfs_dirent *sd,
181 struct inode *inode)
182{
183}
184
185#endif /* CONFIG_LOCKDEP */
186
187int configfs_create(struct dentry * dentry, int mode, int (*init)(struct inode *))
188{
189 int error = 0;
190 struct inode * inode = NULL;
191 if (dentry) {
192 if (!dentry->d_inode) {
193 struct configfs_dirent *sd = dentry->d_fsdata;
194 if ((inode = configfs_new_inode(mode, sd))) {
195 if (dentry->d_parent && dentry->d_parent->d_inode) {
196 struct inode *p_inode = dentry->d_parent->d_inode;
197 p_inode->i_mtime = p_inode->i_ctime = CURRENT_TIME;
198 }
199 configfs_set_inode_lock_class(sd, inode);
200 goto Proceed;
201 }
202 else
203 error = -ENOMEM;
204 } else
205 error = -EEXIST;
206 } else
207 error = -ENOENT;
208 goto Done;
209
210 Proceed:
211 if (init)
212 error = init(inode);
213 if (!error) {
214 d_instantiate(dentry, inode);
215 if (S_ISDIR(mode) || S_ISLNK(mode))
216 dget(dentry); /* pin link and directory dentries in core */
217 } else
218 iput(inode);
219 Done:
220 return error;
221}
222
223/*
224 * Get the name for corresponding element represented by the given configfs_dirent
225 */
226const unsigned char * configfs_get_name(struct configfs_dirent *sd)
227{
228 struct configfs_attribute *attr;
229
230 BUG_ON(!sd || !sd->s_element);
231
232 /* These always have a dentry, so use that */
233 if (sd->s_type & (CONFIGFS_DIR | CONFIGFS_ITEM_LINK))
234 return sd->s_dentry->d_name.name;
235
236 if (sd->s_type & CONFIGFS_ITEM_ATTR) {
237 attr = sd->s_element;
238 return attr->ca_name;
239 }
240 return NULL;
241}
242
243
244/*
245 * Unhashes the dentry corresponding to given configfs_dirent
246 * Called with parent inode's i_mutex held.
247 */
248void configfs_drop_dentry(struct configfs_dirent * sd, struct dentry * parent)
249{
250 struct dentry * dentry = sd->s_dentry;
251
252 if (dentry) {
253 spin_lock(&dentry->d_lock);
254 if (!(d_unhashed(dentry) && dentry->d_inode)) {
255 dget_dlock(dentry);
256 __d_drop(dentry);
257 spin_unlock(&dentry->d_lock);
258 simple_unlink(parent->d_inode, dentry);
259 } else
260 spin_unlock(&dentry->d_lock);
261 }
262}
263
264void configfs_hash_and_remove(struct dentry * dir, const char * name)
265{
266 struct configfs_dirent * sd;
267 struct configfs_dirent * parent_sd = dir->d_fsdata;
268
269 if (dir->d_inode == NULL)
270 /* no inode means this hasn't been made visible yet */
271 return;
272
273 mutex_lock(&dir->d_inode->i_mutex);
274 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
275 if (!sd->s_element)
276 continue;
277 if (!strcmp(configfs_get_name(sd), name)) {
278 spin_lock(&configfs_dirent_lock);
279 list_del_init(&sd->s_sibling);
280 spin_unlock(&configfs_dirent_lock);
281 configfs_drop_dentry(sd, dir);
282 configfs_put(sd);
283 break;
284 }
285 }
286 mutex_unlock(&dir->d_inode->i_mutex);
287}
288
289int __init configfs_inode_init(void)
290{
291 return bdi_init(&configfs_backing_dev_info);
292}
293
294void __exit configfs_inode_exit(void)
295{
296 bdi_destroy(&configfs_backing_dev_info);
297}