1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * inode.c - basic inode and dentry operations.
6 * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
8 * configfs Copyright (C) 2005 Oracle. All rights reserved.
10 * Please see Documentation/filesystems/configfs.rst for more
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>
24 #include <linux/configfs.h>
25 #include "configfs_internal.h"
28 static struct lock_class_key default_group_class[MAX_LOCK_DEPTH];
31 static const struct address_space_operations configfs_aops = {
32 .readpage = simple_readpage,
33 .write_begin = simple_write_begin,
34 .write_end = simple_write_end,
37 static const struct inode_operations configfs_inode_operations ={
38 .setattr = configfs_setattr,
41 int configfs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
44 struct inode * inode = d_inode(dentry);
45 struct configfs_dirent * sd = dentry->d_fsdata;
46 struct iattr * sd_iattr;
47 unsigned int ia_valid = iattr->ia_valid;
53 sd_iattr = sd->s_iattr;
55 /* setting attributes for the first time, allocate now */
56 sd_iattr = kzalloc(sizeof(struct iattr), GFP_KERNEL);
59 /* assign default attributes */
60 sd_iattr->ia_mode = sd->s_mode;
61 sd_iattr->ia_uid = GLOBAL_ROOT_UID;
62 sd_iattr->ia_gid = GLOBAL_ROOT_GID;
63 sd_iattr->ia_atime = sd_iattr->ia_mtime =
64 sd_iattr->ia_ctime = current_time(inode);
65 sd->s_iattr = sd_iattr;
67 /* attributes were changed atleast once in past */
69 error = simple_setattr(mnt_userns, dentry, iattr);
73 if (ia_valid & ATTR_UID)
74 sd_iattr->ia_uid = iattr->ia_uid;
75 if (ia_valid & ATTR_GID)
76 sd_iattr->ia_gid = iattr->ia_gid;
77 if (ia_valid & ATTR_ATIME)
78 sd_iattr->ia_atime = iattr->ia_atime;
79 if (ia_valid & ATTR_MTIME)
80 sd_iattr->ia_mtime = iattr->ia_mtime;
81 if (ia_valid & ATTR_CTIME)
82 sd_iattr->ia_ctime = iattr->ia_ctime;
83 if (ia_valid & ATTR_MODE) {
84 umode_t mode = iattr->ia_mode;
86 if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
88 sd_iattr->ia_mode = sd->s_mode = mode;
94 static inline void set_default_inode_attr(struct inode * inode, umode_t mode)
97 inode->i_atime = inode->i_mtime =
98 inode->i_ctime = current_time(inode);
101 static inline void set_inode_attr(struct inode * inode, struct iattr * iattr)
103 inode->i_mode = iattr->ia_mode;
104 inode->i_uid = iattr->ia_uid;
105 inode->i_gid = iattr->ia_gid;
106 inode->i_atime = iattr->ia_atime;
107 inode->i_mtime = iattr->ia_mtime;
108 inode->i_ctime = iattr->ia_ctime;
111 struct inode *configfs_new_inode(umode_t mode, struct configfs_dirent *sd,
112 struct super_block *s)
114 struct inode * inode = new_inode(s);
116 inode->i_ino = get_next_ino();
117 inode->i_mapping->a_ops = &configfs_aops;
118 inode->i_op = &configfs_inode_operations;
121 /* sysfs_dirent has non-default attributes
122 * get them for the new inode from persistent copy
125 set_inode_attr(inode, sd->s_iattr);
127 set_default_inode_attr(inode, mode);
132 #ifdef CONFIG_LOCKDEP
134 static void configfs_set_inode_lock_class(struct configfs_dirent *sd,
137 int depth = sd->s_depth;
140 if (depth <= ARRAY_SIZE(default_group_class)) {
141 lockdep_set_class(&inode->i_rwsem,
142 &default_group_class[depth - 1]);
145 * In practice the maximum level of locking depth is
146 * already reached. Just inform about possible reasons.
148 pr_info("Too many levels of inodes for the locking correctness validator.\n");
149 pr_info("Spurious warnings may appear.\n");
154 #else /* CONFIG_LOCKDEP */
156 static void configfs_set_inode_lock_class(struct configfs_dirent *sd,
161 #endif /* CONFIG_LOCKDEP */
163 struct inode *configfs_create(struct dentry *dentry, umode_t mode)
165 struct inode *inode = NULL;
166 struct configfs_dirent *sd;
167 struct inode *p_inode;
170 return ERR_PTR(-ENOENT);
172 if (d_really_is_positive(dentry))
173 return ERR_PTR(-EEXIST);
175 sd = dentry->d_fsdata;
176 inode = configfs_new_inode(mode, sd, dentry->d_sb);
178 return ERR_PTR(-ENOMEM);
180 p_inode = d_inode(dentry->d_parent);
181 p_inode->i_mtime = p_inode->i_ctime = current_time(p_inode);
182 configfs_set_inode_lock_class(sd, inode);
187 * Get the name for corresponding element represented by the given configfs_dirent
189 const unsigned char * configfs_get_name(struct configfs_dirent *sd)
191 struct configfs_attribute *attr;
193 BUG_ON(!sd || !sd->s_element);
195 /* These always have a dentry, so use that */
196 if (sd->s_type & (CONFIGFS_DIR | CONFIGFS_ITEM_LINK))
197 return sd->s_dentry->d_name.name;
199 if (sd->s_type & (CONFIGFS_ITEM_ATTR | CONFIGFS_ITEM_BIN_ATTR)) {
200 attr = sd->s_element;
201 return attr->ca_name;
208 * Unhashes the dentry corresponding to given configfs_dirent
209 * Called with parent inode's i_mutex held.
211 void configfs_drop_dentry(struct configfs_dirent * sd, struct dentry * parent)
213 struct dentry * dentry = sd->s_dentry;
216 spin_lock(&dentry->d_lock);
217 if (simple_positive(dentry)) {
220 spin_unlock(&dentry->d_lock);
221 simple_unlink(d_inode(parent), dentry);
223 spin_unlock(&dentry->d_lock);
227 void configfs_hash_and_remove(struct dentry * dir, const char * name)
229 struct configfs_dirent * sd;
230 struct configfs_dirent * parent_sd = dir->d_fsdata;
232 if (d_really_is_negative(dir))
233 /* no inode means this hasn't been made visible yet */
236 inode_lock(d_inode(dir));
237 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
240 if (!strcmp(configfs_get_name(sd), name)) {
241 spin_lock(&configfs_dirent_lock);
242 list_del_init(&sd->s_sibling);
243 spin_unlock(&configfs_dirent_lock);
244 configfs_drop_dentry(sd, dir);
249 inode_unlock(d_inode(dir));