summaryrefslogtreecommitdiff
path: root/fs/btrfs/acl.c
blob: fb3e64d37cb4ca6d2faf4fadefd85b1477a95f2e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
/*
 * Copyright (C) 2007 Red Hat.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License v2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 */

#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/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 = POSIX_ACL_XATTR_ACCESS;
		break;
	case ACL_TYPE_DEFAULT:
		name = POSIX_ACL_XATTR_DEFAULT;
		break;
	default:
		BUG();
	}

	size = __btrfs_getxattr(inode, name, "", 0);
	if (size > 0) {
		value = kzalloc(size, GFP_NOFS);
		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 == -ENOENT || size == -ENODATA || size == 0) {
		/* FIXME, who returns -ENOENT?  I think nobody */
		acl = NULL;
	} else {
		acl = ERR_PTR(-EIO);
	}
	kfree(value);

	if (!IS_ERR(acl))
		set_cached_acl(inode, type, acl);

	return acl;
}

/*
 * Needs to be called with fs_mutex held
 */
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 = POSIX_ACL_XATTR_ACCESS;
		if (acl) {
			ret = posix_acl_update_mode(inode, &inode->i_mode, &acl);
			if (ret)
				return ret;
		}
		ret = 0;
		break;
	case ACL_TYPE_DEFAULT:
		if (!S_ISDIR(inode->i_mode))
			return acl ? -EINVAL : 0;
		name = POSIX_ACL_XATTR_DEFAULT;
		break;
	default:
		return -EINVAL;
	}

	if (acl) {
		size = posix_acl_xattr_size(acl->a_count);
		value = kmalloc(size, GFP_NOFS);
		if (!value) {
			ret = -ENOMEM;
			goto out;
		}

		ret = posix_acl_to_xattr(&init_user_ns, acl, value, size);
		if (ret < 0)
			goto out;
	}

	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)
{
	return __btrfs_set_acl(NULL, inode, acl, type);
}

/*
 * btrfs_init_acl is already generally called under fs_mutex, so the locking
 * stuff has been fixed to work with that.  If the locking stuff changes, we
 * need to re-evaluate the acl locking stuff.
 */
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;
}