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
 57struct posix_acl *ceph_get_acl(struct inode *inode, int type)
 58{
 59	int size;
 60	const char *name;
 61	char *value = NULL;
 62	struct posix_acl *acl;
 63
 64	switch (type) {
 65	case ACL_TYPE_ACCESS:
 66		name = POSIX_ACL_XATTR_ACCESS;
 67		break;
 68	case ACL_TYPE_DEFAULT:
 69		name = POSIX_ACL_XATTR_DEFAULT;
 70		break;
 71	default:
 72		BUG();
 73	}
 74
 75	size = __ceph_getxattr(inode, name, "", 0);
 76	if (size > 0) {
 77		value = kzalloc(size, GFP_NOFS);
 78		if (!value)
 79			return ERR_PTR(-ENOMEM);
 80		size = __ceph_getxattr(inode, name, value, size);
 81	}
 82
 83	if (size > 0)
 84		acl = posix_acl_from_xattr(&init_user_ns, value, size);
 85	else if (size == -ERANGE || size == -ENODATA || size == 0)
 86		acl = NULL;
 87	else
 88		acl = ERR_PTR(-EIO);
 89
 90	kfree(value);
 91
 92	if (!IS_ERR(acl))
 93		ceph_set_cached_acl(inode, type, acl);
 94
 95	return acl;
 96}
 97
 98int ceph_set_acl(struct inode *inode, struct posix_acl *acl, int type)
 99{
100	int ret = 0, size = 0;
101	const char *name = NULL;
102	char *value = NULL;
103	struct iattr newattrs;
104	umode_t new_mode = inode->i_mode, old_mode = inode->i_mode;
105	struct dentry *dentry;
106
107	if (acl) {
108		ret = posix_acl_valid(acl);
109		if (ret < 0)
110			goto out;
111	}
112
113	switch (type) {
114	case ACL_TYPE_ACCESS:
115		name = POSIX_ACL_XATTR_ACCESS;
116		if (acl) {
117			ret = posix_acl_equiv_mode(acl, &new_mode);
118			if (ret < 0)
119				goto out;
120			if (ret == 0)
121				acl = NULL;
122		}
123		break;
124	case ACL_TYPE_DEFAULT:
125		if (!S_ISDIR(inode->i_mode)) {
126			ret = acl ? -EINVAL : 0;
127			goto out;
128		}
129		name = POSIX_ACL_XATTR_DEFAULT;
130		break;
131	default:
132		ret = -EINVAL;
133		goto out;
134	}
135
136	if (acl) {
137		size = posix_acl_xattr_size(acl->a_count);
138		value = kmalloc(size, GFP_NOFS);
139		if (!value) {
140			ret = -ENOMEM;
141			goto out;
142		}
143
144		ret = posix_acl_to_xattr(&init_user_ns, acl, value, size);
145		if (ret < 0)
146			goto out_free;
147	}
148
149	dentry = d_find_alias(inode);
150	if (new_mode != old_mode) {
151		newattrs.ia_mode = new_mode;
152		newattrs.ia_valid = ATTR_MODE;
153		ret = ceph_setattr(dentry, &newattrs);
154		if (ret)
155			goto out_dput;
156	}
157
158	ret = __ceph_setxattr(dentry, name, value, size, 0);
159	if (ret) {
160		if (new_mode != old_mode) {
161			newattrs.ia_mode = old_mode;
162			newattrs.ia_valid = ATTR_MODE;
163			ceph_setattr(dentry, &newattrs);
164		}
165		goto out_dput;
166	}
167
168	ceph_set_cached_acl(inode, type, acl);
169
170out_dput:
171	dput(dentry);
172out_free:
173	kfree(value);
174out:
175	return ret;
176}
177
178int ceph_init_acl(struct dentry *dentry, struct inode *inode, struct inode *dir)
179{
180	struct posix_acl *default_acl, *acl;
181	int error;
182
183	error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
184	if (error)
185		return error;
186
187	if (!default_acl && !acl)
188		cache_no_acl(inode);
189
190	if (default_acl) {
191		error = ceph_set_acl(inode, default_acl, ACL_TYPE_DEFAULT);
192		posix_acl_release(default_acl);
193	}
194	if (acl) {
195		if (!error)
196			error = ceph_set_acl(inode, acl, ACL_TYPE_ACCESS);
197		posix_acl_release(acl);
198	}
199	return error;
200}