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
15 #include "ctree.h"
16 #include "btrfs_inode.h"
17 #include "xattr.h"
18
btrfs_get_acl(struct inode * inode,int type)19 struct posix_acl *btrfs_get_acl(struct inode *inode, int type)
20 {
21 int size;
22 const char *name;
23 char *value = NULL;
24 struct posix_acl *acl;
25
26 switch (type) {
27 case ACL_TYPE_ACCESS:
28 name = XATTR_NAME_POSIX_ACL_ACCESS;
29 break;
30 case ACL_TYPE_DEFAULT:
31 name = XATTR_NAME_POSIX_ACL_DEFAULT;
32 break;
33 default:
34 return ERR_PTR(-EINVAL);
35 }
36
37 size = btrfs_getxattr(inode, name, NULL, 0);
38 if (size > 0) {
39 value = kzalloc(size, GFP_KERNEL);
40 if (!value)
41 return ERR_PTR(-ENOMEM);
42 size = btrfs_getxattr(inode, name, value, size);
43 }
44 if (size > 0)
45 acl = posix_acl_from_xattr(&init_user_ns, value, size);
46 else if (size == -ENODATA || size == 0)
47 acl = NULL;
48 else
49 acl = ERR_PTR(size);
50 kfree(value);
51
52 return acl;
53 }
54
__btrfs_set_acl(struct btrfs_trans_handle * trans,struct inode * inode,struct posix_acl * acl,int type)55 static int __btrfs_set_acl(struct btrfs_trans_handle *trans,
56 struct inode *inode, struct posix_acl *acl, int type)
57 {
58 int ret, size = 0;
59 const char *name;
60 char *value = NULL;
61
62 switch (type) {
63 case ACL_TYPE_ACCESS:
64 name = XATTR_NAME_POSIX_ACL_ACCESS;
65 break;
66 case ACL_TYPE_DEFAULT:
67 if (!S_ISDIR(inode->i_mode))
68 return acl ? -EINVAL : 0;
69 name = XATTR_NAME_POSIX_ACL_DEFAULT;
70 break;
71 default:
72 return -EINVAL;
73 }
74
75 if (acl) {
76 unsigned int nofs_flag;
77
78 size = posix_acl_xattr_size(acl->a_count);
79 /*
80 * We're holding a transaction handle, so use a NOFS memory
81 * allocation context to avoid deadlock if reclaim happens.
82 */
83 nofs_flag = memalloc_nofs_save();
84 value = kmalloc(size, GFP_KERNEL);
85 memalloc_nofs_restore(nofs_flag);
86 if (!value) {
87 ret = -ENOMEM;
88 goto out;
89 }
90
91 ret = posix_acl_to_xattr(&init_user_ns, acl, value, size);
92 if (ret < 0)
93 goto out;
94 }
95
96 if (trans)
97 ret = btrfs_setxattr(trans, inode, name, value, size, 0);
98 else
99 ret = btrfs_setxattr_trans(inode, name, value, size, 0);
100
101 out:
102 kfree(value);
103
104 if (!ret)
105 set_cached_acl(inode, type, acl);
106
107 return ret;
108 }
109
btrfs_set_acl(struct inode * inode,struct posix_acl * acl,int type)110 int btrfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
111 {
112 int ret;
113 umode_t old_mode = inode->i_mode;
114
115 if (type == ACL_TYPE_ACCESS && acl) {
116 ret = posix_acl_update_mode(inode, &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
btrfs_init_acl(struct btrfs_trans_handle * trans,struct inode * inode,struct inode * dir)126 int btrfs_init_acl(struct btrfs_trans_handle *trans,
127 struct inode *inode, struct inode *dir)
128 {
129 struct posix_acl *default_acl, *acl;
130 int ret = 0;
131
132 /* this happens with subvols */
133 if (!dir)
134 return 0;
135
136 ret = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
137 if (ret)
138 return ret;
139
140 if (default_acl) {
141 ret = __btrfs_set_acl(trans, inode, default_acl,
142 ACL_TYPE_DEFAULT);
143 posix_acl_release(default_acl);
144 }
145
146 if (acl) {
147 if (!ret)
148 ret = __btrfs_set_acl(trans, inode, acl,
149 ACL_TYPE_ACCESS);
150 posix_acl_release(acl);
151 }
152
153 if (!default_acl && !acl)
154 cache_no_acl(inode);
155 return ret;
156 }
157