linux-stable/fs/kernfs/inode.c
Linus Torvalds 14ab6d425e vfs-6.7.ctime
-----BEGIN PGP SIGNATURE-----
 
 iHUEABYKAB0WIQRAhzRXHqcMeLMyaSiRxhvAZXjcogUCZTppYgAKCRCRxhvAZXjc
 okIHAP9anLz1QDyMLH12ASuHjgBc0Of3jcB6NB97IWGpL4O21gEA46ohaD+vcJuC
 YkBLU3lXqQ87nfu28ExFAzh10hG2jwM=
 =m4pB
 -----END PGP SIGNATURE-----

Merge tag 'vfs-6.7.ctime' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs

Pull vfs inode time accessor updates from Christian Brauner:
 "This finishes the conversion of all inode time fields to accessor
  functions as discussed on list. Changing timestamps manually as we
  used to do before is error prone. Using accessors function makes this
  robust.

  It does not contain the switch of the time fields to discrete 64 bit
  integers to replace struct timespec and free up space in struct inode.
  But after this, the switch can be trivially made and the patch should
  only affect the vfs if we decide to do it"

* tag 'vfs-6.7.ctime' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs: (86 commits)
  fs: rename inode i_atime and i_mtime fields
  security: convert to new timestamp accessors
  selinux: convert to new timestamp accessors
  apparmor: convert to new timestamp accessors
  sunrpc: convert to new timestamp accessors
  mm: convert to new timestamp accessors
  bpf: convert to new timestamp accessors
  ipc: convert to new timestamp accessors
  linux: convert to new timestamp accessors
  zonefs: convert to new timestamp accessors
  xfs: convert to new timestamp accessors
  vboxsf: convert to new timestamp accessors
  ufs: convert to new timestamp accessors
  udf: convert to new timestamp accessors
  ubifs: convert to new timestamp accessors
  tracefs: convert to new timestamp accessors
  sysv: convert to new timestamp accessors
  squashfs: convert to new timestamp accessors
  server: convert to new timestamp accessors
  client: convert to new timestamp accessors
  ...
2023-10-30 09:47:13 -10:00

453 lines
11 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* fs/kernfs/inode.c - kernfs inode implementation
*
* Copyright (c) 2001-3 Patrick Mochel
* Copyright (c) 2007 SUSE Linux Products GmbH
* Copyright (c) 2007, 2013 Tejun Heo <tj@kernel.org>
*/
#include <linux/pagemap.h>
#include <linux/backing-dev.h>
#include <linux/capability.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/xattr.h>
#include <linux/security.h>
#include "kernfs-internal.h"
static const struct inode_operations kernfs_iops = {
.permission = kernfs_iop_permission,
.setattr = kernfs_iop_setattr,
.getattr = kernfs_iop_getattr,
.listxattr = kernfs_iop_listxattr,
};
static struct kernfs_iattrs *__kernfs_iattrs(struct kernfs_node *kn, int alloc)
{
static DEFINE_MUTEX(iattr_mutex);
struct kernfs_iattrs *ret;
mutex_lock(&iattr_mutex);
if (kn->iattr || !alloc)
goto out_unlock;
kn->iattr = kmem_cache_zalloc(kernfs_iattrs_cache, GFP_KERNEL);
if (!kn->iattr)
goto out_unlock;
/* assign default attributes */
kn->iattr->ia_uid = GLOBAL_ROOT_UID;
kn->iattr->ia_gid = GLOBAL_ROOT_GID;
ktime_get_real_ts64(&kn->iattr->ia_atime);
kn->iattr->ia_mtime = kn->iattr->ia_atime;
kn->iattr->ia_ctime = kn->iattr->ia_atime;
simple_xattrs_init(&kn->iattr->xattrs);
atomic_set(&kn->iattr->nr_user_xattrs, 0);
atomic_set(&kn->iattr->user_xattr_size, 0);
out_unlock:
ret = kn->iattr;
mutex_unlock(&iattr_mutex);
return ret;
}
static struct kernfs_iattrs *kernfs_iattrs(struct kernfs_node *kn)
{
return __kernfs_iattrs(kn, 1);
}
static struct kernfs_iattrs *kernfs_iattrs_noalloc(struct kernfs_node *kn)
{
return __kernfs_iattrs(kn, 0);
}
int __kernfs_setattr(struct kernfs_node *kn, const struct iattr *iattr)
{
struct kernfs_iattrs *attrs;
unsigned int ia_valid = iattr->ia_valid;
attrs = kernfs_iattrs(kn);
if (!attrs)
return -ENOMEM;
if (ia_valid & ATTR_UID)
attrs->ia_uid = iattr->ia_uid;
if (ia_valid & ATTR_GID)
attrs->ia_gid = iattr->ia_gid;
if (ia_valid & ATTR_ATIME)
attrs->ia_atime = iattr->ia_atime;
if (ia_valid & ATTR_MTIME)
attrs->ia_mtime = iattr->ia_mtime;
if (ia_valid & ATTR_CTIME)
attrs->ia_ctime = iattr->ia_ctime;
if (ia_valid & ATTR_MODE)
kn->mode = iattr->ia_mode;
return 0;
}
/**
* kernfs_setattr - set iattr on a node
* @kn: target node
* @iattr: iattr to set
*
* Return: %0 on success, -errno on failure.
*/
int kernfs_setattr(struct kernfs_node *kn, const struct iattr *iattr)
{
int ret;
struct kernfs_root *root = kernfs_root(kn);
down_write(&root->kernfs_iattr_rwsem);
ret = __kernfs_setattr(kn, iattr);
up_write(&root->kernfs_iattr_rwsem);
return ret;
}
int kernfs_iop_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
struct iattr *iattr)
{
struct inode *inode = d_inode(dentry);
struct kernfs_node *kn = inode->i_private;
struct kernfs_root *root;
int error;
if (!kn)
return -EINVAL;
root = kernfs_root(kn);
down_write(&root->kernfs_iattr_rwsem);
error = setattr_prepare(&nop_mnt_idmap, dentry, iattr);
if (error)
goto out;
error = __kernfs_setattr(kn, iattr);
if (error)
goto out;
/* this ignores size changes */
setattr_copy(&nop_mnt_idmap, inode, iattr);
out:
up_write(&root->kernfs_iattr_rwsem);
return error;
}
ssize_t kernfs_iop_listxattr(struct dentry *dentry, char *buf, size_t size)
{
struct kernfs_node *kn = kernfs_dentry_node(dentry);
struct kernfs_iattrs *attrs;
attrs = kernfs_iattrs(kn);
if (!attrs)
return -ENOMEM;
return simple_xattr_list(d_inode(dentry), &attrs->xattrs, buf, size);
}
static inline void set_default_inode_attr(struct inode *inode, umode_t mode)
{
inode->i_mode = mode;
simple_inode_init_ts(inode);
}
static inline void set_inode_attr(struct inode *inode,
struct kernfs_iattrs *attrs)
{
inode->i_uid = attrs->ia_uid;
inode->i_gid = attrs->ia_gid;
inode_set_atime_to_ts(inode, attrs->ia_atime);
inode_set_mtime_to_ts(inode, attrs->ia_mtime);
inode_set_ctime_to_ts(inode, attrs->ia_ctime);
}
static void kernfs_refresh_inode(struct kernfs_node *kn, struct inode *inode)
{
struct kernfs_iattrs *attrs = kn->iattr;
inode->i_mode = kn->mode;
if (attrs)
/*
* kernfs_node has non-default attributes get them from
* persistent copy in kernfs_node.
*/
set_inode_attr(inode, attrs);
if (kernfs_type(kn) == KERNFS_DIR)
set_nlink(inode, kn->dir.subdirs + 2);
}
int kernfs_iop_getattr(struct mnt_idmap *idmap,
const struct path *path, struct kstat *stat,
u32 request_mask, unsigned int query_flags)
{
struct inode *inode = d_inode(path->dentry);
struct kernfs_node *kn = inode->i_private;
struct kernfs_root *root = kernfs_root(kn);
down_read(&root->kernfs_iattr_rwsem);
kernfs_refresh_inode(kn, inode);
generic_fillattr(&nop_mnt_idmap, request_mask, inode, stat);
up_read(&root->kernfs_iattr_rwsem);
return 0;
}
static void kernfs_init_inode(struct kernfs_node *kn, struct inode *inode)
{
kernfs_get(kn);
inode->i_private = kn;
inode->i_mapping->a_ops = &ram_aops;
inode->i_op = &kernfs_iops;
inode->i_generation = kernfs_gen(kn);
set_default_inode_attr(inode, kn->mode);
kernfs_refresh_inode(kn, inode);
/* initialize inode according to type */
switch (kernfs_type(kn)) {
case KERNFS_DIR:
inode->i_op = &kernfs_dir_iops;
inode->i_fop = &kernfs_dir_fops;
if (kn->flags & KERNFS_EMPTY_DIR)
make_empty_dir_inode(inode);
break;
case KERNFS_FILE:
inode->i_size = kn->attr.size;
inode->i_fop = &kernfs_file_fops;
break;
case KERNFS_LINK:
inode->i_op = &kernfs_symlink_iops;
break;
default:
BUG();
}
unlock_new_inode(inode);
}
/**
* kernfs_get_inode - get inode for kernfs_node
* @sb: super block
* @kn: kernfs_node to allocate inode for
*
* Get inode for @kn. If such inode doesn't exist, a new inode is
* allocated and basics are initialized. New inode is returned
* locked.
*
* Locking:
* Kernel thread context (may sleep).
*
* Return:
* Pointer to allocated inode on success, %NULL on failure.
*/
struct inode *kernfs_get_inode(struct super_block *sb, struct kernfs_node *kn)
{
struct inode *inode;
inode = iget_locked(sb, kernfs_ino(kn));
if (inode && (inode->i_state & I_NEW))
kernfs_init_inode(kn, inode);
return inode;
}
/*
* The kernfs_node serves as both an inode and a directory entry for
* kernfs. To prevent the kernfs inode numbers from being freed
* prematurely we take a reference to kernfs_node from the kernfs inode. A
* super_operations.evict_inode() implementation is needed to drop that
* reference upon inode destruction.
*/
void kernfs_evict_inode(struct inode *inode)
{
struct kernfs_node *kn = inode->i_private;
truncate_inode_pages_final(&inode->i_data);
clear_inode(inode);
kernfs_put(kn);
}
int kernfs_iop_permission(struct mnt_idmap *idmap,
struct inode *inode, int mask)
{
struct kernfs_node *kn;
struct kernfs_root *root;
int ret;
if (mask & MAY_NOT_BLOCK)
return -ECHILD;
kn = inode->i_private;
root = kernfs_root(kn);
down_read(&root->kernfs_iattr_rwsem);
kernfs_refresh_inode(kn, inode);
ret = generic_permission(&nop_mnt_idmap, inode, mask);
up_read(&root->kernfs_iattr_rwsem);
return ret;
}
int kernfs_xattr_get(struct kernfs_node *kn, const char *name,
void *value, size_t size)
{
struct kernfs_iattrs *attrs = kernfs_iattrs_noalloc(kn);
if (!attrs)
return -ENODATA;
return simple_xattr_get(&attrs->xattrs, name, value, size);
}
int kernfs_xattr_set(struct kernfs_node *kn, const char *name,
const void *value, size_t size, int flags)
{
struct simple_xattr *old_xattr;
struct kernfs_iattrs *attrs = kernfs_iattrs(kn);
if (!attrs)
return -ENOMEM;
old_xattr = simple_xattr_set(&attrs->xattrs, name, value, size, flags);
if (IS_ERR(old_xattr))
return PTR_ERR(old_xattr);
simple_xattr_free(old_xattr);
return 0;
}
static int kernfs_vfs_xattr_get(const struct xattr_handler *handler,
struct dentry *unused, struct inode *inode,
const char *suffix, void *value, size_t size)
{
const char *name = xattr_full_name(handler, suffix);
struct kernfs_node *kn = inode->i_private;
return kernfs_xattr_get(kn, name, value, size);
}
static int kernfs_vfs_xattr_set(const struct xattr_handler *handler,
struct mnt_idmap *idmap,
struct dentry *unused, struct inode *inode,
const char *suffix, const void *value,
size_t size, int flags)
{
const char *name = xattr_full_name(handler, suffix);
struct kernfs_node *kn = inode->i_private;
return kernfs_xattr_set(kn, name, value, size, flags);
}
static int kernfs_vfs_user_xattr_add(struct kernfs_node *kn,
const char *full_name,
struct simple_xattrs *xattrs,
const void *value, size_t size, int flags)
{
atomic_t *sz = &kn->iattr->user_xattr_size;
atomic_t *nr = &kn->iattr->nr_user_xattrs;
struct simple_xattr *old_xattr;
int ret;
if (atomic_inc_return(nr) > KERNFS_MAX_USER_XATTRS) {
ret = -ENOSPC;
goto dec_count_out;
}
if (atomic_add_return(size, sz) > KERNFS_USER_XATTR_SIZE_LIMIT) {
ret = -ENOSPC;
goto dec_size_out;
}
old_xattr = simple_xattr_set(xattrs, full_name, value, size, flags);
if (!old_xattr)
return 0;
if (IS_ERR(old_xattr)) {
ret = PTR_ERR(old_xattr);
goto dec_size_out;
}
ret = 0;
size = old_xattr->size;
simple_xattr_free(old_xattr);
dec_size_out:
atomic_sub(size, sz);
dec_count_out:
atomic_dec(nr);
return ret;
}
static int kernfs_vfs_user_xattr_rm(struct kernfs_node *kn,
const char *full_name,
struct simple_xattrs *xattrs,
const void *value, size_t size, int flags)
{
atomic_t *sz = &kn->iattr->user_xattr_size;
atomic_t *nr = &kn->iattr->nr_user_xattrs;
struct simple_xattr *old_xattr;
old_xattr = simple_xattr_set(xattrs, full_name, value, size, flags);
if (!old_xattr)
return 0;
if (IS_ERR(old_xattr))
return PTR_ERR(old_xattr);
atomic_sub(old_xattr->size, sz);
atomic_dec(nr);
simple_xattr_free(old_xattr);
return 0;
}
static int kernfs_vfs_user_xattr_set(const struct xattr_handler *handler,
struct mnt_idmap *idmap,
struct dentry *unused, struct inode *inode,
const char *suffix, const void *value,
size_t size, int flags)
{
const char *full_name = xattr_full_name(handler, suffix);
struct kernfs_node *kn = inode->i_private;
struct kernfs_iattrs *attrs;
if (!(kernfs_root(kn)->flags & KERNFS_ROOT_SUPPORT_USER_XATTR))
return -EOPNOTSUPP;
attrs = kernfs_iattrs(kn);
if (!attrs)
return -ENOMEM;
if (value)
return kernfs_vfs_user_xattr_add(kn, full_name, &attrs->xattrs,
value, size, flags);
else
return kernfs_vfs_user_xattr_rm(kn, full_name, &attrs->xattrs,
value, size, flags);
}
static const struct xattr_handler kernfs_trusted_xattr_handler = {
.prefix = XATTR_TRUSTED_PREFIX,
.get = kernfs_vfs_xattr_get,
.set = kernfs_vfs_xattr_set,
};
static const struct xattr_handler kernfs_security_xattr_handler = {
.prefix = XATTR_SECURITY_PREFIX,
.get = kernfs_vfs_xattr_get,
.set = kernfs_vfs_xattr_set,
};
static const struct xattr_handler kernfs_user_xattr_handler = {
.prefix = XATTR_USER_PREFIX,
.get = kernfs_vfs_xattr_get,
.set = kernfs_vfs_user_xattr_set,
};
const struct xattr_handler * const kernfs_xattr_handlers[] = {
&kernfs_trusted_xattr_handler,
&kernfs_security_xattr_handler,
&kernfs_user_xattr_handler,
NULL
};