acl.c revision 758582361976e9640a1cb9516c0af10cdf8e4753 
1/*
2 * linux/fs/ceph/acl.c
3 *
4 * Copyright (C) 2013 Guangliang Zhao, <lucienchao@gmail.com>
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public
8 * License v2 as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13 * General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public
16 * License along with this program; if not, write to the
17 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
18 * Boston, MA 021110-1307, USA.
19 */
20
21#include <linux/ceph/ceph_debug.h>
22#include <linux/fs.h>
23#include <linux/string.h>
24#include <linux/xattr.h>
25#include <linux/posix_acl_xattr.h>
26#include <linux/posix_acl.h>
27#include <linux/sched.h>
28#include <linux/slab.h>
29
30#include "super.h"
31
32static inline void ceph_set_cached_acl(struct inode *inode,
33					int type, struct posix_acl *acl)
34{
35	struct ceph_inode_info *ci = ceph_inode(inode);
36
37	spin_lock(&ci->i_ceph_lock);
38	if (__ceph_caps_issued_mask(ci, CEPH_CAP_XATTR_SHARED, 0))
39		set_cached_acl(inode, type, acl);
40	spin_unlock(&ci->i_ceph_lock);
41}
42
43static inline struct posix_acl *ceph_get_cached_acl(struct inode *inode,
44							int type)
45{
46	struct ceph_inode_info *ci = ceph_inode(inode);
47	struct posix_acl *acl = ACL_NOT_CACHED;
48
49	spin_lock(&ci->i_ceph_lock);
50	if (__ceph_caps_issued_mask(ci, CEPH_CAP_XATTR_SHARED, 0))
51		acl = get_cached_acl(inode, type);
52	spin_unlock(&ci->i_ceph_lock);
53
54	return acl;
55}
56
57void ceph_forget_all_cached_acls(struct inode *inode)
58{
59	forget_all_cached_acls(inode);
60}
61
62struct posix_acl *ceph_get_acl(struct inode *inode, int type)
63{
64	int size;
65	const char *name;
66	char *value = NULL;
67	struct posix_acl *acl;
68
69	switch (type) {
70	case ACL_TYPE_ACCESS:
71		name = POSIX_ACL_XATTR_ACCESS;
72		break;
73	case ACL_TYPE_DEFAULT:
74		name = POSIX_ACL_XATTR_DEFAULT;
75		break;
76	default:
77		BUG();
78	}
79
80	size = __ceph_getxattr(inode, name, "", 0);
81	if (size > 0) {
82		value = kzalloc(size, GFP_NOFS);
83		if (!value)
84			return ERR_PTR(-ENOMEM);
85		size = __ceph_getxattr(inode, name, value, size);
86	}
87
88	if (size > 0)
89		acl = posix_acl_from_xattr(&init_user_ns, value, size);
90	else if (size == -ERANGE || size == -ENODATA || size == 0)
91		acl = NULL;
92	else
93		acl = ERR_PTR(-EIO);
94
95	kfree(value);
96
97	if (!IS_ERR(acl))
98		ceph_set_cached_acl(inode, type, acl);
99
100	return acl;
101}
102
103int ceph_set_acl(struct inode *inode, struct posix_acl *acl, int type)
104{
105	int ret = 0, size = 0;
106	const char *name = NULL;
107	char *value = NULL;
108	struct iattr newattrs;
109	umode_t new_mode = inode->i_mode, old_mode = inode->i_mode;
110	struct dentry *dentry = d_find_alias(inode);
111
112	if (acl) {
113		ret = posix_acl_valid(acl);
114		if (ret < 0)
115			goto out;
116	}
117
118	switch (type) {
119	case ACL_TYPE_ACCESS:
120		name = POSIX_ACL_XATTR_ACCESS;
121		if (acl) {
122			ret = posix_acl_equiv_mode(acl, &new_mode);
123			if (ret < 0)
124				goto out;
125			if (ret == 0)
126				acl = NULL;
127		}
128		break;
129	case ACL_TYPE_DEFAULT:
130		if (!S_ISDIR(inode->i_mode)) {
131			ret = acl ? -EINVAL : 0;
132			goto out;
133		}
134		name = POSIX_ACL_XATTR_DEFAULT;
135		break;
136	default:
137		ret = -EINVAL;
138		goto out;
139	}
140
141	if (acl) {
142		size = posix_acl_xattr_size(acl->a_count);
143		value = kmalloc(size, GFP_NOFS);
144		if (!value) {
145			ret = -ENOMEM;
146			goto out;
147		}
148
149		ret = posix_acl_to_xattr(&init_user_ns, acl, value, size);
150		if (ret < 0)
151			goto out_free;
152	}
153
154	if (new_mode != old_mode) {
155		newattrs.ia_mode = new_mode;
156		newattrs.ia_valid = ATTR_MODE;
157		ret = ceph_setattr(dentry, &newattrs);
158		if (ret)
159			goto out_free;
160	}
161
162	if (value)
163		ret = __ceph_setxattr(dentry, name, value, size, 0);
164	else
165		ret = __ceph_removexattr(dentry, name);
166
167	if (ret) {
168		if (new_mode != old_mode) {
169			newattrs.ia_mode = old_mode;
170			newattrs.ia_valid = ATTR_MODE;
171			ceph_setattr(dentry, &newattrs);
172		}
173		goto out_free;
174	}
175
176	ceph_set_cached_acl(inode, type, acl);
177
178out_free:
179	kfree(value);
180out:
181	return ret;
182}
183
184int ceph_init_acl(struct dentry *dentry, struct inode *inode, struct inode *dir)
185{
186	struct posix_acl *default_acl, *acl;
187	int error;
188
189	error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
190	if (error)
191		return error;
192
193	if (!default_acl && !acl)
194		cache_no_acl(inode);
195
196	if (default_acl) {
197		error = ceph_set_acl(inode, default_acl, ACL_TYPE_DEFAULT);
198		posix_acl_release(default_acl);
199	}
200	if (acl) {
201		if (!error)
202			error = ceph_set_acl(inode, acl, ACL_TYPE_ACCESS);
203		posix_acl_release(acl);
204	}
205	return error;
206}
207