acl.c
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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2007 Red Hat. All rights reserved.
*/
#include <linux/fs.h>
#include <linux/string.h>
#include <linux/xattr.h>
#include <linux/posix_acl_xattr.h>
#include <linux/posix_acl.h>
#include <linux/sched.h>
#include <linux/sched/mm.h>
#include <linux/slab.h>
#include "ctree.h"
#include "btrfs_inode.h"
#include "xattr.h"
struct posix_acl *btrfs_get_acl(struct inode *inode, int type)
{
int size;
const char *name;
char *value = NULL;
struct posix_acl *acl;
switch (type) {
case ACL_TYPE_ACCESS:
name = XATTR_NAME_POSIX_ACL_ACCESS;
break;
case ACL_TYPE_DEFAULT:
name = XATTR_NAME_POSIX_ACL_DEFAULT;
break;
default:
return ERR_PTR(-EINVAL);
}
size = btrfs_getxattr(inode, name, NULL, 0);
if (size > 0) {
value = kzalloc(size, GFP_KERNEL);
if (!value)
return ERR_PTR(-ENOMEM);
size = btrfs_getxattr(inode, name, value, size);
}
if (size > 0)
acl = posix_acl_from_xattr(&init_user_ns, value, size);
else if (size == -ENODATA || size == 0)
acl = NULL;
else
acl = ERR_PTR(size);
kfree(value);
return acl;
}
static int __btrfs_set_acl(struct btrfs_trans_handle *trans,
struct inode *inode, struct posix_acl *acl, int type)
{
int ret, size = 0;
const char *name;
char *value = NULL;
switch (type) {
case ACL_TYPE_ACCESS:
name = XATTR_NAME_POSIX_ACL_ACCESS;
break;
case ACL_TYPE_DEFAULT:
if (!S_ISDIR(inode->i_mode))
return acl ? -EINVAL : 0;
name = XATTR_NAME_POSIX_ACL_DEFAULT;
break;
default:
return -EINVAL;
}
if (acl) {
unsigned int nofs_flag;
size = posix_acl_xattr_size(acl->a_count);
/*
* We're holding a transaction handle, so use a NOFS memory
* allocation context to avoid deadlock if reclaim happens.
*/
nofs_flag = memalloc_nofs_save();
value = kmalloc(size, GFP_KERNEL);
memalloc_nofs_restore(nofs_flag);
if (!value) {
ret = -ENOMEM;
goto out;
}
ret = posix_acl_to_xattr(&init_user_ns, acl, value, size);
if (ret < 0)
goto out;
}
if (trans)
ret = btrfs_setxattr(trans, inode, name, value, size, 0);
else
ret = btrfs_setxattr_trans(inode, name, value, size, 0);
out:
kfree(value);
if (!ret)
set_cached_acl(inode, type, acl);
return ret;
}
int btrfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
{
int ret;
umode_t old_mode = inode->i_mode;
if (type == ACL_TYPE_ACCESS && acl) {
ret = posix_acl_update_mode(inode, &inode->i_mode, &acl);
if (ret)
return ret;
}
ret = __btrfs_set_acl(NULL, inode, acl, type);
if (ret)
inode->i_mode = old_mode;
return ret;
}
int btrfs_init_acl(struct btrfs_trans_handle *trans,
struct inode *inode, struct inode *dir)
{
struct posix_acl *default_acl, *acl;
int ret = 0;
/* this happens with subvols */
if (!dir)
return 0;
ret = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
if (ret)
return ret;
if (default_acl) {
ret = __btrfs_set_acl(trans, inode, default_acl,
ACL_TYPE_DEFAULT);
posix_acl_release(default_acl);
}
if (acl) {
if (!ret)
ret = __btrfs_set_acl(trans, inode, acl,
ACL_TYPE_ACCESS);
posix_acl_release(acl);
}
if (!default_acl && !acl)
cache_no_acl(inode);
return ret;
}