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v5.4
  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/* -*- mode: c; c-basic-offset: 8; -*-
  3 * vim: noexpandtab sw=8 ts=8 sts=0:
  4 *
  5 * inode.c - basic inode and dentry operations.
  6 *
  7 * Based on sysfs:
  8 * 	sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
  9 *
 10 * configfs Copyright (C) 2005 Oracle.  All rights reserved.
 11 *
 12 * Please see Documentation/filesystems/configfs/configfs.txt for more
 13 * information.
 14 */
 15
 16#undef DEBUG
 17
 18#include <linux/pagemap.h>
 19#include <linux/namei.h>
 20#include <linux/backing-dev.h>
 21#include <linux/capability.h>
 22#include <linux/sched.h>
 23#include <linux/lockdep.h>
 24#include <linux/slab.h>
 25
 26#include <linux/configfs.h>
 27#include "configfs_internal.h"
 28
 29#ifdef CONFIG_LOCKDEP
 30static struct lock_class_key default_group_class[MAX_LOCK_DEPTH];
 31#endif
 32
 33static const struct address_space_operations configfs_aops = {
 34	.readpage	= simple_readpage,
 35	.write_begin	= simple_write_begin,
 36	.write_end	= simple_write_end,
 37};
 38
 39static const struct inode_operations configfs_inode_operations ={
 40	.setattr	= configfs_setattr,
 41};
 42
 43int configfs_setattr(struct dentry * dentry, struct iattr * iattr)
 
 44{
 45	struct inode * inode = d_inode(dentry);
 46	struct configfs_dirent * sd = dentry->d_fsdata;
 47	struct iattr * sd_iattr;
 48	unsigned int ia_valid = iattr->ia_valid;
 49	int error;
 50
 51	if (!sd)
 52		return -EINVAL;
 53
 54	sd_iattr = sd->s_iattr;
 55	if (!sd_iattr) {
 56		/* setting attributes for the first time, allocate now */
 57		sd_iattr = kzalloc(sizeof(struct iattr), GFP_KERNEL);
 58		if (!sd_iattr)
 59			return -ENOMEM;
 60		/* assign default attributes */
 61		sd_iattr->ia_mode = sd->s_mode;
 62		sd_iattr->ia_uid = GLOBAL_ROOT_UID;
 63		sd_iattr->ia_gid = GLOBAL_ROOT_GID;
 64		sd_iattr->ia_atime = sd_iattr->ia_mtime =
 65			sd_iattr->ia_ctime = current_time(inode);
 66		sd->s_iattr = sd_iattr;
 67	}
 68	/* attributes were changed atleast once in past */
 69
 70	error = simple_setattr(dentry, iattr);
 71	if (error)
 72		return error;
 73
 74	if (ia_valid & ATTR_UID)
 75		sd_iattr->ia_uid = iattr->ia_uid;
 76	if (ia_valid & ATTR_GID)
 77		sd_iattr->ia_gid = iattr->ia_gid;
 78	if (ia_valid & ATTR_ATIME)
 79		sd_iattr->ia_atime = timestamp_truncate(iattr->ia_atime,
 80						      inode);
 81	if (ia_valid & ATTR_MTIME)
 82		sd_iattr->ia_mtime = timestamp_truncate(iattr->ia_mtime,
 83						      inode);
 84	if (ia_valid & ATTR_CTIME)
 85		sd_iattr->ia_ctime = timestamp_truncate(iattr->ia_ctime,
 86						      inode);
 87	if (ia_valid & ATTR_MODE) {
 88		umode_t mode = iattr->ia_mode;
 89
 90		if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
 91			mode &= ~S_ISGID;
 92		sd_iattr->ia_mode = sd->s_mode = mode;
 93	}
 94
 95	return error;
 96}
 97
 98static inline void set_default_inode_attr(struct inode * inode, umode_t mode)
 99{
100	inode->i_mode = mode;
101	inode->i_atime = inode->i_mtime =
102		inode->i_ctime = current_time(inode);
103}
104
105static inline void set_inode_attr(struct inode * inode, struct iattr * iattr)
106{
107	inode->i_mode = iattr->ia_mode;
108	inode->i_uid = iattr->ia_uid;
109	inode->i_gid = iattr->ia_gid;
110	inode->i_atime = iattr->ia_atime;
111	inode->i_mtime = iattr->ia_mtime;
112	inode->i_ctime = iattr->ia_ctime;
113}
114
115struct inode *configfs_new_inode(umode_t mode, struct configfs_dirent *sd,
116				 struct super_block *s)
117{
118	struct inode * inode = new_inode(s);
119	if (inode) {
120		inode->i_ino = get_next_ino();
121		inode->i_mapping->a_ops = &configfs_aops;
122		inode->i_op = &configfs_inode_operations;
123
124		if (sd->s_iattr) {
125			/* sysfs_dirent has non-default attributes
126			 * get them for the new inode from persistent copy
127			 * in sysfs_dirent
128			 */
129			set_inode_attr(inode, sd->s_iattr);
130		} else
131			set_default_inode_attr(inode, mode);
132	}
133	return inode;
134}
135
136#ifdef CONFIG_LOCKDEP
137
138static void configfs_set_inode_lock_class(struct configfs_dirent *sd,
139					  struct inode *inode)
140{
141	int depth = sd->s_depth;
142
143	if (depth > 0) {
144		if (depth <= ARRAY_SIZE(default_group_class)) {
145			lockdep_set_class(&inode->i_rwsem,
146					  &default_group_class[depth - 1]);
147		} else {
148			/*
149			 * In practice the maximum level of locking depth is
150			 * already reached. Just inform about possible reasons.
151			 */
152			pr_info("Too many levels of inodes for the locking correctness validator.\n");
153			pr_info("Spurious warnings may appear.\n");
154		}
155	}
156}
157
158#else /* CONFIG_LOCKDEP */
159
160static void configfs_set_inode_lock_class(struct configfs_dirent *sd,
161					  struct inode *inode)
162{
163}
164
165#endif /* CONFIG_LOCKDEP */
166
167struct inode *configfs_create(struct dentry *dentry, umode_t mode)
168{
169	struct inode *inode = NULL;
170	struct configfs_dirent *sd;
171	struct inode *p_inode;
172
173	if (!dentry)
174		return ERR_PTR(-ENOENT);
175
176	if (d_really_is_positive(dentry))
177		return ERR_PTR(-EEXIST);
178
179	sd = dentry->d_fsdata;
180	inode = configfs_new_inode(mode, sd, dentry->d_sb);
181	if (!inode)
182		return ERR_PTR(-ENOMEM);
183
184	p_inode = d_inode(dentry->d_parent);
185	p_inode->i_mtime = p_inode->i_ctime = current_time(p_inode);
186	configfs_set_inode_lock_class(sd, inode);
187	return inode;
188}
189
190/*
191 * Get the name for corresponding element represented by the given configfs_dirent
192 */
193const unsigned char * configfs_get_name(struct configfs_dirent *sd)
194{
195	struct configfs_attribute *attr;
196
197	BUG_ON(!sd || !sd->s_element);
198
199	/* These always have a dentry, so use that */
200	if (sd->s_type & (CONFIGFS_DIR | CONFIGFS_ITEM_LINK))
201		return sd->s_dentry->d_name.name;
202
203	if (sd->s_type & (CONFIGFS_ITEM_ATTR | CONFIGFS_ITEM_BIN_ATTR)) {
204		attr = sd->s_element;
205		return attr->ca_name;
206	}
207	return NULL;
208}
209
210
211/*
212 * Unhashes the dentry corresponding to given configfs_dirent
213 * Called with parent inode's i_mutex held.
214 */
215void configfs_drop_dentry(struct configfs_dirent * sd, struct dentry * parent)
216{
217	struct dentry * dentry = sd->s_dentry;
218
219	if (dentry) {
220		spin_lock(&dentry->d_lock);
221		if (simple_positive(dentry)) {
222			dget_dlock(dentry);
223			__d_drop(dentry);
224			spin_unlock(&dentry->d_lock);
225			simple_unlink(d_inode(parent), dentry);
226		} else
227			spin_unlock(&dentry->d_lock);
228	}
229}
230
231void configfs_hash_and_remove(struct dentry * dir, const char * name)
232{
233	struct configfs_dirent * sd;
234	struct configfs_dirent * parent_sd = dir->d_fsdata;
235
236	if (d_really_is_negative(dir))
237		/* no inode means this hasn't been made visible yet */
238		return;
239
240	inode_lock(d_inode(dir));
241	list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
242		if (!sd->s_element)
243			continue;
244		if (!strcmp(configfs_get_name(sd), name)) {
245			spin_lock(&configfs_dirent_lock);
246			list_del_init(&sd->s_sibling);
247			spin_unlock(&configfs_dirent_lock);
248			configfs_drop_dentry(sd, dir);
249			configfs_put(sd);
250			break;
251		}
252	}
253	inode_unlock(d_inode(dir));
254}
v6.8
  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 mnt_idmap *idmap, 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(idmap, 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	simple_inode_init_ts(inode);
 
 92}
 93
 94static inline void set_inode_attr(struct inode * inode, struct iattr * iattr)
 95{
 96	inode->i_mode = iattr->ia_mode;
 97	inode->i_uid = iattr->ia_uid;
 98	inode->i_gid = iattr->ia_gid;
 99	inode_set_atime_to_ts(inode, iattr->ia_atime);
100	inode_set_mtime_to_ts(inode, iattr->ia_mtime);
101	inode_set_ctime_to_ts(inode, iattr->ia_ctime);
102}
103
104struct inode *configfs_new_inode(umode_t mode, struct configfs_dirent *sd,
105				 struct super_block *s)
106{
107	struct inode * inode = new_inode(s);
108	if (inode) {
109		inode->i_ino = get_next_ino();
110		inode->i_mapping->a_ops = &ram_aops;
111		inode->i_op = &configfs_inode_operations;
112
113		if (sd->s_iattr) {
114			/* sysfs_dirent has non-default attributes
115			 * get them for the new inode from persistent copy
116			 * in sysfs_dirent
117			 */
118			set_inode_attr(inode, sd->s_iattr);
119		} else
120			set_default_inode_attr(inode, mode);
121	}
122	return inode;
123}
124
125#ifdef CONFIG_LOCKDEP
126
127static void configfs_set_inode_lock_class(struct configfs_dirent *sd,
128					  struct inode *inode)
129{
130	int depth = sd->s_depth;
131
132	if (depth > 0) {
133		if (depth <= ARRAY_SIZE(default_group_class)) {
134			lockdep_set_class(&inode->i_rwsem,
135					  &default_group_class[depth - 1]);
136		} else {
137			/*
138			 * In practice the maximum level of locking depth is
139			 * already reached. Just inform about possible reasons.
140			 */
141			pr_info("Too many levels of inodes for the locking correctness validator.\n");
142			pr_info("Spurious warnings may appear.\n");
143		}
144	}
145}
146
147#else /* CONFIG_LOCKDEP */
148
149static void configfs_set_inode_lock_class(struct configfs_dirent *sd,
150					  struct inode *inode)
151{
152}
153
154#endif /* CONFIG_LOCKDEP */
155
156struct inode *configfs_create(struct dentry *dentry, umode_t mode)
157{
158	struct inode *inode = NULL;
159	struct configfs_dirent *sd;
160	struct inode *p_inode;
161
162	if (!dentry)
163		return ERR_PTR(-ENOENT);
164
165	if (d_really_is_positive(dentry))
166		return ERR_PTR(-EEXIST);
167
168	sd = dentry->d_fsdata;
169	inode = configfs_new_inode(mode, sd, dentry->d_sb);
170	if (!inode)
171		return ERR_PTR(-ENOMEM);
172
173	p_inode = d_inode(dentry->d_parent);
174	inode_set_mtime_to_ts(p_inode, inode_set_ctime_current(p_inode));
175	configfs_set_inode_lock_class(sd, inode);
176	return inode;
177}
178
179/*
180 * Get the name for corresponding element represented by the given configfs_dirent
181 */
182const unsigned char * configfs_get_name(struct configfs_dirent *sd)
183{
184	struct configfs_attribute *attr;
185
186	BUG_ON(!sd || !sd->s_element);
187
188	/* These always have a dentry, so use that */
189	if (sd->s_type & (CONFIGFS_DIR | CONFIGFS_ITEM_LINK))
190		return sd->s_dentry->d_name.name;
191
192	if (sd->s_type & (CONFIGFS_ITEM_ATTR | CONFIGFS_ITEM_BIN_ATTR)) {
193		attr = sd->s_element;
194		return attr->ca_name;
195	}
196	return NULL;
197}
198
199
200/*
201 * Unhashes the dentry corresponding to given configfs_dirent
202 * Called with parent inode's i_mutex held.
203 */
204void configfs_drop_dentry(struct configfs_dirent * sd, struct dentry * parent)
205{
206	struct dentry * dentry = sd->s_dentry;
207
208	if (dentry) {
209		spin_lock(&dentry->d_lock);
210		if (simple_positive(dentry)) {
211			dget_dlock(dentry);
212			__d_drop(dentry);
213			spin_unlock(&dentry->d_lock);
214			simple_unlink(d_inode(parent), dentry);
215		} else
216			spin_unlock(&dentry->d_lock);
217	}
218}
219
220void configfs_hash_and_remove(struct dentry * dir, const char * name)
221{
222	struct configfs_dirent * sd;
223	struct configfs_dirent * parent_sd = dir->d_fsdata;
224
225	if (d_really_is_negative(dir))
226		/* no inode means this hasn't been made visible yet */
227		return;
228
229	inode_lock(d_inode(dir));
230	list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
231		if (!sd->s_element)
232			continue;
233		if (!strcmp(configfs_get_name(sd), name)) {
234			spin_lock(&configfs_dirent_lock);
235			list_del_init(&sd->s_sibling);
236			spin_unlock(&configfs_dirent_lock);
237			configfs_drop_dentry(sd, dir);
238			configfs_put(sd);
239			break;
240		}
241	}
242	inode_unlock(d_inode(dir));
243}