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 "xattr.h"
16#include "acl.h"
17#include "misc.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 AUTO_KFREE(value);
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
54 return acl;
55}
56
57int __btrfs_set_acl(struct btrfs_trans_handle *trans, struct inode *inode,
58 struct posix_acl *acl, int type)
59{
60 int ret, size = 0;
61 const char *name;
62 char AUTO_KFREE(value);
63
64 switch (type) {
65 case ACL_TYPE_ACCESS:
66 name = XATTR_NAME_POSIX_ACL_ACCESS;
67 break;
68 case ACL_TYPE_DEFAULT:
69 if (!S_ISDIR(inode->i_mode))
70 return acl ? -EINVAL : 0;
71 name = XATTR_NAME_POSIX_ACL_DEFAULT;
72 break;
73 default:
74 return -EINVAL;
75 }
76
77 if (acl) {
78 unsigned int nofs_flag;
79
80 size = posix_acl_xattr_size(count: acl->a_count);
81 /*
82 * We're holding a transaction handle, so use a NOFS memory
83 * allocation context to avoid deadlock if reclaim happens.
84 */
85 nofs_flag = memalloc_nofs_save();
86 value = kmalloc(size, GFP_KERNEL);
87 memalloc_nofs_restore(flags: nofs_flag);
88 if (!value)
89 return -ENOMEM;
90
91 ret = posix_acl_to_xattr(user_ns: &init_user_ns, acl, buffer: value, size);
92 if (ret < 0)
93 return ret;
94 }
95
96 if (trans)
97 ret = btrfs_setxattr(trans, inode, name, value, size, flags: 0);
98 else
99 ret = btrfs_setxattr_trans(inode, name, value, size, flags: 0);
100 if (ret < 0)
101 return ret;
102
103 set_cached_acl(inode, type, acl);
104 return 0;
105}
106
107int btrfs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
108 struct posix_acl *acl, int type)
109{
110 int ret;
111 struct inode *inode = d_inode(dentry);
112 umode_t old_mode = inode->i_mode;
113
114 if (type == ACL_TYPE_ACCESS && acl) {
115 ret = posix_acl_update_mode(idmap, inode,
116 &inode->i_mode, &acl);
117 if (ret)
118 return ret;
119 }
120 ret = __btrfs_set_acl(NULL, inode, acl, type);
121 if (ret)
122 inode->i_mode = old_mode;
123 return ret;
124}
125

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