1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2007 Red Hat. All rights reserved.
4 */
5
6#include <linux/fs.h>
7#include <linux/string.h>
8#include <linux/xattr.h>
9#include <linux/posix_acl_xattr.h>
10#include <linux/posix_acl.h>
11#include <linux/sched.h>
12#include <linux/sched/mm.h>
13#include <linux/slab.h>
14#include "ctree.h"
15#include "btrfs_inode.h"
16#include "xattr.h"
17#include "acl.h"
18
19struct posix_acl *btrfs_get_acl(struct inode *inode, int type, bool rcu)
20{
21 int size;
22 const char *name;
23 char *value = NULL;
24 struct posix_acl *acl;
25
26 if (rcu)
27 return ERR_PTR(error: -ECHILD);
28
29 switch (type) {
30 case ACL_TYPE_ACCESS:
31 name = XATTR_NAME_POSIX_ACL_ACCESS;
32 break;
33 case ACL_TYPE_DEFAULT:
34 name = XATTR_NAME_POSIX_ACL_DEFAULT;
35 break;
36 default:
37 return ERR_PTR(error: -EINVAL);
38 }
39
40 size = btrfs_getxattr(inode, name, NULL, size: 0);
41 if (size > 0) {
42 value = kzalloc(size, GFP_KERNEL);
43 if (!value)
44 return ERR_PTR(error: -ENOMEM);
45 size = btrfs_getxattr(inode, name, buffer: value, size);
46 }
47 if (size > 0)
48 acl = posix_acl_from_xattr(user_ns: &init_user_ns, value, size);
49 else if (size == -ENODATA || size == 0)
50 acl = NULL;
51 else
52 acl = ERR_PTR(error: size);
53 kfree(objp: value);
54
55 return acl;
56}
57
58int __btrfs_set_acl(struct btrfs_trans_handle *trans, struct inode *inode,
59 struct posix_acl *acl, int type)
60{
61 int ret, size = 0;
62 const char *name;
63 char *value = NULL;
64
65 switch (type) {
66 case ACL_TYPE_ACCESS:
67 name = XATTR_NAME_POSIX_ACL_ACCESS;
68 break;
69 case ACL_TYPE_DEFAULT:
70 if (!S_ISDIR(inode->i_mode))
71 return acl ? -EINVAL : 0;
72 name = XATTR_NAME_POSIX_ACL_DEFAULT;
73 break;
74 default:
75 return -EINVAL;
76 }
77
78 if (acl) {
79 unsigned int nofs_flag;
80
81 size = posix_acl_xattr_size(count: acl->a_count);
82 /*
83 * We're holding a transaction handle, so use a NOFS memory
84 * allocation context to avoid deadlock if reclaim happens.
85 */
86 nofs_flag = memalloc_nofs_save();
87 value = kmalloc(size, GFP_KERNEL);
88 memalloc_nofs_restore(flags: nofs_flag);
89 if (!value) {
90 ret = -ENOMEM;
91 goto out;
92 }
93
94 ret = posix_acl_to_xattr(user_ns: &init_user_ns, acl, buffer: value, size);
95 if (ret < 0)
96 goto out;
97 }
98
99 if (trans)
100 ret = btrfs_setxattr(trans, inode, name, value, size, flags: 0);
101 else
102 ret = btrfs_setxattr_trans(inode, name, value, size, flags: 0);
103
104out:
105 kfree(objp: value);
106
107 if (!ret)
108 set_cached_acl(inode, type, acl);
109
110 return ret;
111}
112
113int btrfs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
114 struct posix_acl *acl, int type)
115{
116 int ret;
117 struct inode *inode = d_inode(dentry);
118 umode_t old_mode = inode->i_mode;
119
120 if (type == ACL_TYPE_ACCESS && acl) {
121 ret = posix_acl_update_mode(idmap, inode,
122 &inode->i_mode, &acl);
123 if (ret)
124 return ret;
125 }
126 ret = __btrfs_set_acl(NULL, inode, acl, type);
127 if (ret)
128 inode->i_mode = old_mode;
129 return ret;
130}
131

source code of linux/fs/btrfs/acl.c