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// SPDX-License-Identifier: GPL-2.0-or-later
/* -*- mode: c; c-basic-offset: 8; -*-
* vim: noexpandtab sw=8 ts=8 sts=0:
*
* inode.c - basic inode and dentry operations.
*
* Based on sysfs:
* sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
*
* configfs Copyright (C) 2005 Oracle. All rights reserved.
*
* Please see Documentation/filesystems/configfs.rst for more
* information.
*/
#undef DEBUG
#include <linux/pagemap.h>
#include <linux/namei.h>
#include <linux/backing-dev.h>
#include <linux/capability.h>
#include <linux/sched.h>
#include <linux/lockdep.h>
#include <linux/slab.h>
#include <linux/configfs.h>
#include "configfs_internal.h"
#ifdef CONFIG_LOCKDEP
static struct lock_class_key default_group_class[MAX_LOCK_DEPTH];
#endif
static const struct address_space_operations configfs_aops = {
.readpage = simple_readpage,
.write_begin = simple_write_begin,
.write_end = simple_write_end,
};
static const struct inode_operations configfs_inode_operations ={
.setattr = configfs_setattr,
};
int configfs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
struct iattr *iattr)
{
struct inode * inode = d_inode(dentry);
struct configfs_dirent * sd = dentry->d_fsdata;
struct iattr * sd_iattr;
unsigned int ia_valid = iattr->ia_valid;
int error;
if (!sd)
return -EINVAL;
sd_iattr = sd->s_iattr;
if (!sd_iattr) {
/* setting attributes for the first time, allocate now */
sd_iattr = kzalloc(sizeof(struct iattr), GFP_KERNEL);
if (!sd_iattr)
return -ENOMEM;
/* assign default attributes */
sd_iattr->ia_mode = sd->s_mode;
sd_iattr->ia_uid = GLOBAL_ROOT_UID;
sd_iattr->ia_gid = GLOBAL_ROOT_GID;
sd_iattr->ia_atime = sd_iattr->ia_mtime =
sd_iattr->ia_ctime = current_time(inode);
sd->s_iattr = sd_iattr;
}
/* attributes were changed atleast once in past */
error = simple_setattr(mnt_userns, dentry, iattr);
if (error)
return error;
if (ia_valid & ATTR_UID)
sd_iattr->ia_uid = iattr->ia_uid;
if (ia_valid & ATTR_GID)
sd_iattr->ia_gid = iattr->ia_gid;
if (ia_valid & ATTR_ATIME)
sd_iattr->ia_atime = iattr->ia_atime;
if (ia_valid & ATTR_MTIME)
sd_iattr->ia_mtime = iattr->ia_mtime;
if (ia_valid & ATTR_CTIME)
sd_iattr->ia_ctime = iattr->ia_ctime;
if (ia_valid & ATTR_MODE) {
umode_t mode = iattr->ia_mode;
if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
mode &= ~S_ISGID;
sd_iattr->ia_mode = sd->s_mode = mode;
}
return error;
}
static inline void set_default_inode_attr(struct inode * inode, umode_t mode)
{
inode->i_mode = mode;
inode->i_atime = inode->i_mtime =
inode->i_ctime = current_time(inode);
}
static inline void set_inode_attr(struct inode * inode, struct iattr * iattr)
{
inode->i_mode = iattr->ia_mode;
inode->i_uid = iattr->ia_uid;
inode->i_gid = iattr->ia_gid;
inode->i_atime = iattr->ia_atime;
inode->i_mtime = iattr->ia_mtime;
inode->i_ctime = iattr->ia_ctime;
}
struct inode *configfs_new_inode(umode_t mode, struct configfs_dirent *sd,
struct super_block *s)
{
struct inode * inode = new_inode(s);
if (inode) {
inode->i_ino = get_next_ino();
inode->i_mapping->a_ops = &configfs_aops;
inode->i_op = &configfs_inode_operations;
if (sd->s_iattr) {
/* sysfs_dirent has non-default attributes
* get them for the new inode from persistent copy
* in sysfs_dirent
*/
set_inode_attr(inode, sd->s_iattr);
} else
set_default_inode_attr(inode, mode);
}
return inode;
}
#ifdef CONFIG_LOCKDEP
static void configfs_set_inode_lock_class(struct configfs_dirent *sd,
struct inode *inode)
{
int depth = sd->s_depth;
if (depth > 0) {
if (depth <= ARRAY_SIZE(default_group_class)) {
lockdep_set_class(&inode->i_rwsem,
&default_group_class[depth - 1]);
} else {
/*
* In practice the maximum level of locking depth is
* already reached. Just inform about possible reasons.
*/
pr_info("Too many levels of inodes for the locking correctness validator.\n");
pr_info("Spurious warnings may appear.\n");
}
}
}
#else /* CONFIG_LOCKDEP */
static void configfs_set_inode_lock_class(struct configfs_dirent *sd,
struct inode *inode)
{
}
#endif /* CONFIG_LOCKDEP */
struct inode *configfs_create(struct dentry *dentry, umode_t mode)
{
struct inode *inode = NULL;
struct configfs_dirent *sd;
struct inode *p_inode;
if (!dentry)
return ERR_PTR(-ENOENT);
if (d_really_is_positive(dentry))
return ERR_PTR(-EEXIST);
sd = dentry->d_fsdata;
inode = configfs_new_inode(mode, sd, dentry->d_sb);
if (!inode)
return ERR_PTR(-ENOMEM);
p_inode = d_inode(dentry->d_parent);
p_inode->i_mtime = p_inode->i_ctime = current_time(p_inode);
configfs_set_inode_lock_class(sd, inode);
return inode;
}
/*
* Get the name for corresponding element represented by the given configfs_dirent
*/
const unsigned char * configfs_get_name(struct configfs_dirent *sd)
{
struct configfs_attribute *attr;
BUG_ON(!sd || !sd->s_element);
/* These always have a dentry, so use that */
if (sd->s_type & (CONFIGFS_DIR | CONFIGFS_ITEM_LINK))
return sd->s_dentry->d_name.name;
if (sd->s_type & (CONFIGFS_ITEM_ATTR | CONFIGFS_ITEM_BIN_ATTR)) {
attr = sd->s_element;
return attr->ca_name;
}
return NULL;
}
/*
* Unhashes the dentry corresponding to given configfs_dirent
* Called with parent inode's i_mutex held.
*/
void configfs_drop_dentry(struct configfs_dirent * sd, struct dentry * parent)
{
struct dentry * dentry = sd->s_dentry;
if (dentry) {
spin_lock(&dentry->d_lock);
if (simple_positive(dentry)) {
dget_dlock(dentry);
__d_drop(dentry);
spin_unlock(&dentry->d_lock);
simple_unlink(d_inode(parent), dentry);
} else
spin_unlock(&dentry->d_lock);
}
}
void configfs_hash_and_remove(struct dentry * dir, const char * name)
{
struct configfs_dirent * sd;
struct configfs_dirent * parent_sd = dir->d_fsdata;
if (d_really_is_negative(dir))
/* no inode means this hasn't been made visible yet */
return;
inode_lock(d_inode(dir));
list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
if (!sd->s_element)
continue;
if (!strcmp(configfs_get_name(sd), name)) {
spin_lock(&configfs_dirent_lock);
list_del_init(&sd->s_sibling);
spin_unlock(&configfs_dirent_lock);
configfs_drop_dentry(sd, dir);
configfs_put(sd);
break;
}
}
inode_unlock(d_inode(dir));
}
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