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
18 struct posix_acl *btrfs_get_acl(struct inode *inode, int type, bool rcu)
19 {
20 int size;
21 const char *name;
22 char *value = NULL;
23 struct posix_acl *acl;
24
25 if (rcu)
26 return ERR_PTR(-ECHILD);
27
28 switch (type) {
29 case ACL_TYPE_ACCESS:
30 name = XATTR_NAME_POSIX_ACL_ACCESS;
31 break;
32 case ACL_TYPE_DEFAULT:
33 name = XATTR_NAME_POSIX_ACL_DEFAULT;
34 break;
35 default:
36 return ERR_PTR(-EINVAL);
37 }
38
39 size = btrfs_getxattr(inode, name, NULL, 0);
40 if (size > 0) {
41 value = kzalloc(size, GFP_KERNEL);
42 if (!value)
43 return ERR_PTR(-ENOMEM);
44 size = btrfs_getxattr(inode, name, value, size);
45 }
46 if (size > 0)
47 acl = posix_acl_from_xattr(&init_user_ns, value, size);
48 else if (size == -ENODATA || size == 0)
49 acl = NULL;
50 else
51 acl = ERR_PTR(size);
52 kfree(value);
53
54 return acl;
55 }
56
57 int __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 *value = NULL;
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(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(nofs_flag);
88 if (!value) {
89 ret = -ENOMEM;
90 goto out;
91 }
92
93 ret = posix_acl_to_xattr(&init_user_ns, acl, value, size);
94 if (ret < 0)
95 goto out;
96 }
97
98 if (trans)
99 ret = btrfs_setxattr(trans, inode, name, value, size, 0);
100 else
101 ret = btrfs_setxattr_trans(inode, name, value, size, 0);
102
103 out:
104 kfree(value);
105
106 if (!ret)
107 set_cached_acl(inode, type, acl);
108
109 return ret;
110 }
111
112 int btrfs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
113 struct posix_acl *acl, int type)
114 {
115 int ret;
116 struct inode *inode = d_inode(dentry);
117 umode_t old_mode = inode->i_mode;
118
119 if (type == ACL_TYPE_ACCESS && acl) {
120 ret = posix_acl_update_mode(idmap, inode,
121 &inode->i_mode, &acl);
122 if (ret)
123 return ret;
124 }
125 ret = __btrfs_set_acl(NULL, inode, acl, type);
126 if (ret)
127 inode->i_mode = old_mode;
128 return ret;
129 }
130
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.