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 inode_operations configfs_inode_operations ={
32 .setattr = configfs_setattr,
35 int configfs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
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;
47 sd_iattr = sd->s_iattr;
49 /* setting attributes for the first time, allocate now */
50 sd_iattr = kzalloc(sizeof(struct iattr), GFP_KERNEL);
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;
61 /* attributes were changed atleast once in past */
63 error = simple_setattr(idmap, dentry, iattr);
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;
80 if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
82 sd_iattr->ia_mode = sd->s_mode = mode;
88 static inline void set_default_inode_attr(struct inode * inode, umode_t mode)
91 inode->i_atime = inode->i_mtime = inode_set_ctime_current(inode);
94 static inline void set_inode_attr(struct inode * inode, struct iattr * iattr)
96 inode->i_mode = iattr->ia_mode;
97 inode->i_uid = iattr->ia_uid;
98 inode->i_gid = iattr->ia_gid;
99 inode->i_atime = iattr->ia_atime;
100 inode->i_mtime = iattr->ia_mtime;
101 inode_set_ctime_to_ts(inode, iattr->ia_ctime);
104 struct inode *configfs_new_inode(umode_t mode, struct configfs_dirent *sd,
105 struct super_block *s)
107 struct inode * inode = new_inode(s);
109 inode->i_ino = get_next_ino();
110 inode->i_mapping->a_ops = &ram_aops;
111 inode->i_op = &configfs_inode_operations;
114 /* sysfs_dirent has non-default attributes
115 * get them for the new inode from persistent copy
118 set_inode_attr(inode, sd->s_iattr);
120 set_default_inode_attr(inode, mode);
125 #ifdef CONFIG_LOCKDEP
127 static void configfs_set_inode_lock_class(struct configfs_dirent *sd,
130 int depth = sd->s_depth;
133 if (depth <= ARRAY_SIZE(default_group_class)) {
134 lockdep_set_class(&inode->i_rwsem,
135 &default_group_class[depth - 1]);
138 * In practice the maximum level of locking depth is
139 * already reached. Just inform about possible reasons.
141 pr_info("Too many levels of inodes for the locking correctness validator.\n");
142 pr_info("Spurious warnings may appear.\n");
147 #else /* CONFIG_LOCKDEP */
149 static void configfs_set_inode_lock_class(struct configfs_dirent *sd,
154 #endif /* CONFIG_LOCKDEP */
156 struct inode *configfs_create(struct dentry *dentry, umode_t mode)
158 struct inode *inode = NULL;
159 struct configfs_dirent *sd;
160 struct inode *p_inode;
163 return ERR_PTR(-ENOENT);
165 if (d_really_is_positive(dentry))
166 return ERR_PTR(-EEXIST);
168 sd = dentry->d_fsdata;
169 inode = configfs_new_inode(mode, sd, dentry->d_sb);
171 return ERR_PTR(-ENOMEM);
173 p_inode = d_inode(dentry->d_parent);
174 p_inode->i_mtime = inode_set_ctime_current(p_inode);
175 configfs_set_inode_lock_class(sd, inode);
180 * Get the name for corresponding element represented by the given configfs_dirent
182 const unsigned char * configfs_get_name(struct configfs_dirent *sd)
184 struct configfs_attribute *attr;
186 BUG_ON(!sd || !sd->s_element);
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;
192 if (sd->s_type & (CONFIGFS_ITEM_ATTR | CONFIGFS_ITEM_BIN_ATTR)) {
193 attr = sd->s_element;
194 return attr->ca_name;
201 * Unhashes the dentry corresponding to given configfs_dirent
202 * Called with parent inode's i_mutex held.
204 void configfs_drop_dentry(struct configfs_dirent * sd, struct dentry * parent)
206 struct dentry * dentry = sd->s_dentry;
209 spin_lock(&dentry->d_lock);
210 if (simple_positive(dentry)) {
213 spin_unlock(&dentry->d_lock);
214 simple_unlink(d_inode(parent), dentry);
216 spin_unlock(&dentry->d_lock);
220 void configfs_hash_and_remove(struct dentry * dir, const char * name)
222 struct configfs_dirent * sd;
223 struct configfs_dirent * parent_sd = dir->d_fsdata;
225 if (d_really_is_negative(dir))
226 /* no inode means this hasn't been made visible yet */
229 inode_lock(d_inode(dir));
230 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
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);
242 inode_unlock(d_inode(dir));