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:
5 * inode.c - basic inode and dentry operations.
8 * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
10 * configfs Copyright (C) 2005 Oracle. All rights reserved.
12 * Please see Documentation/filesystems/configfs.rst for more
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>
26 #include <linux/configfs.h>
27 #include "configfs_internal.h"
30 static struct lock_class_key default_group_class[MAX_LOCK_DEPTH];
33 static const struct address_space_operations configfs_aops = {
34 .readpage = simple_readpage,
35 .write_begin = simple_write_begin,
36 .write_end = simple_write_end,
39 static const struct inode_operations configfs_inode_operations ={
40 .setattr = configfs_setattr,
43 int configfs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
46 struct inode * inode = d_inode(dentry);
47 struct configfs_dirent * sd = dentry->d_fsdata;
48 struct iattr * sd_iattr;
49 unsigned int ia_valid = iattr->ia_valid;
55 sd_iattr = sd->s_iattr;
57 /* setting attributes for the first time, allocate now */
58 sd_iattr = kzalloc(sizeof(struct iattr), GFP_KERNEL);
61 /* assign default attributes */
62 sd_iattr->ia_mode = sd->s_mode;
63 sd_iattr->ia_uid = GLOBAL_ROOT_UID;
64 sd_iattr->ia_gid = GLOBAL_ROOT_GID;
65 sd_iattr->ia_atime = sd_iattr->ia_mtime =
66 sd_iattr->ia_ctime = current_time(inode);
67 sd->s_iattr = sd_iattr;
69 /* attributes were changed atleast once in past */
71 error = simple_setattr(mnt_userns, dentry, iattr);
75 if (ia_valid & ATTR_UID)
76 sd_iattr->ia_uid = iattr->ia_uid;
77 if (ia_valid & ATTR_GID)
78 sd_iattr->ia_gid = iattr->ia_gid;
79 if (ia_valid & ATTR_ATIME)
80 sd_iattr->ia_atime = iattr->ia_atime;
81 if (ia_valid & ATTR_MTIME)
82 sd_iattr->ia_mtime = iattr->ia_mtime;
83 if (ia_valid & ATTR_CTIME)
84 sd_iattr->ia_ctime = iattr->ia_ctime;
85 if (ia_valid & ATTR_MODE) {
86 umode_t mode = iattr->ia_mode;
88 if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
90 sd_iattr->ia_mode = sd->s_mode = mode;
96 static inline void set_default_inode_attr(struct inode * inode, umode_t mode)
99 inode->i_atime = inode->i_mtime =
100 inode->i_ctime = current_time(inode);
103 static inline void set_inode_attr(struct inode * inode, struct iattr * iattr)
105 inode->i_mode = iattr->ia_mode;
106 inode->i_uid = iattr->ia_uid;
107 inode->i_gid = iattr->ia_gid;
108 inode->i_atime = iattr->ia_atime;
109 inode->i_mtime = iattr->ia_mtime;
110 inode->i_ctime = iattr->ia_ctime;
113 struct inode *configfs_new_inode(umode_t mode, struct configfs_dirent *sd,
114 struct super_block *s)
116 struct inode * inode = new_inode(s);
118 inode->i_ino = get_next_ino();
119 inode->i_mapping->a_ops = &configfs_aops;
120 inode->i_op = &configfs_inode_operations;
123 /* sysfs_dirent has non-default attributes
124 * get them for the new inode from persistent copy
127 set_inode_attr(inode, sd->s_iattr);
129 set_default_inode_attr(inode, mode);
134 #ifdef CONFIG_LOCKDEP
136 static void configfs_set_inode_lock_class(struct configfs_dirent *sd,
139 int depth = sd->s_depth;
142 if (depth <= ARRAY_SIZE(default_group_class)) {
143 lockdep_set_class(&inode->i_rwsem,
144 &default_group_class[depth - 1]);
147 * In practice the maximum level of locking depth is
148 * already reached. Just inform about possible reasons.
150 pr_info("Too many levels of inodes for the locking correctness validator.\n");
151 pr_info("Spurious warnings may appear.\n");
156 #else /* CONFIG_LOCKDEP */
158 static void configfs_set_inode_lock_class(struct configfs_dirent *sd,
163 #endif /* CONFIG_LOCKDEP */
165 struct inode *configfs_create(struct dentry *dentry, umode_t mode)
167 struct inode *inode = NULL;
168 struct configfs_dirent *sd;
169 struct inode *p_inode;
172 return ERR_PTR(-ENOENT);
174 if (d_really_is_positive(dentry))
175 return ERR_PTR(-EEXIST);
177 sd = dentry->d_fsdata;
178 inode = configfs_new_inode(mode, sd, dentry->d_sb);
180 return ERR_PTR(-ENOMEM);
182 p_inode = d_inode(dentry->d_parent);
183 p_inode->i_mtime = p_inode->i_ctime = current_time(p_inode);
184 configfs_set_inode_lock_class(sd, inode);
189 * Get the name for corresponding element represented by the given configfs_dirent
191 const unsigned char * configfs_get_name(struct configfs_dirent *sd)
193 struct configfs_attribute *attr;
195 BUG_ON(!sd || !sd->s_element);
197 /* These always have a dentry, so use that */
198 if (sd->s_type & (CONFIGFS_DIR | CONFIGFS_ITEM_LINK))
199 return sd->s_dentry->d_name.name;
201 if (sd->s_type & (CONFIGFS_ITEM_ATTR | CONFIGFS_ITEM_BIN_ATTR)) {
202 attr = sd->s_element;
203 return attr->ca_name;
210 * Unhashes the dentry corresponding to given configfs_dirent
211 * Called with parent inode's i_mutex held.
213 void configfs_drop_dentry(struct configfs_dirent * sd, struct dentry * parent)
215 struct dentry * dentry = sd->s_dentry;
218 spin_lock(&dentry->d_lock);
219 if (simple_positive(dentry)) {
222 spin_unlock(&dentry->d_lock);
223 simple_unlink(d_inode(parent), dentry);
225 spin_unlock(&dentry->d_lock);
229 void configfs_hash_and_remove(struct dentry * dir, const char * name)
231 struct configfs_dirent * sd;
232 struct configfs_dirent * parent_sd = dir->d_fsdata;
234 if (d_really_is_negative(dir))
235 /* no inode means this hasn't been made visible yet */
238 inode_lock(d_inode(dir));
239 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
242 if (!strcmp(configfs_get_name(sd), name)) {
243 spin_lock(&configfs_dirent_lock);
244 list_del_init(&sd->s_sibling);
245 spin_unlock(&configfs_dirent_lock);
246 configfs_drop_dentry(sd, dir);
251 inode_unlock(d_inode(dir));