xref: /linux/fs/gfs2/acl.c (revision fbce3befd60d40639bf3c6b60f7477b2f988f92d)
1 /*
2  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
3  * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
4  *
5  * This copyrighted material is made available to anyone wishing to use,
6  * modify, copy, or redistribute it subject to the terms and conditions
7  * of the GNU General Public License version 2.
8  */
9 
10 #include <linux/sched.h>
11 #include <linux/slab.h>
12 #include <linux/spinlock.h>
13 #include <linux/completion.h>
14 #include <linux/buffer_head.h>
15 #include <linux/xattr.h>
16 #include <linux/posix_acl.h>
17 #include <linux/posix_acl_xattr.h>
18 #include <linux/gfs2_ondisk.h>
19 
20 #include "gfs2.h"
21 #include "incore.h"
22 #include "acl.h"
23 #include "xattr.h"
24 #include "glock.h"
25 #include "inode.h"
26 #include "meta_io.h"
27 #include "trans.h"
28 #include "util.h"
29 
30 static const char *gfs2_acl_name(int type)
31 {
32 	switch (type) {
33 	case ACL_TYPE_ACCESS:
34 		return XATTR_POSIX_ACL_ACCESS;
35 	case ACL_TYPE_DEFAULT:
36 		return XATTR_POSIX_ACL_DEFAULT;
37 	}
38 	return NULL;
39 }
40 
41 struct posix_acl *gfs2_get_acl(struct inode *inode, int type)
42 {
43 	struct gfs2_inode *ip = GFS2_I(inode);
44 	struct posix_acl *acl;
45 	const char *name;
46 	char *data;
47 	int len;
48 
49 	if (!ip->i_eattr)
50 		return NULL;
51 
52 	name = gfs2_acl_name(type);
53 	if (name == NULL)
54 		return ERR_PTR(-EINVAL);
55 
56 	len = gfs2_xattr_acl_get(ip, name, &data);
57 	if (len < 0)
58 		return ERR_PTR(len);
59 	if (len == 0)
60 		return NULL;
61 
62 	acl = posix_acl_from_xattr(&init_user_ns, data, len);
63 	kfree(data);
64 	return acl;
65 }
66 
67 int gfs2_set_acl(struct inode *inode, struct posix_acl *acl, int type)
68 {
69 	int error;
70 	int len;
71 	char *data;
72 	const char *name = gfs2_acl_name(type);
73 
74 	BUG_ON(name == NULL);
75 
76 	if (acl && acl->a_count > GFS2_ACL_MAX_ENTRIES(GFS2_SB(inode)))
77 		return -E2BIG;
78 
79 	if (type == ACL_TYPE_ACCESS) {
80 		umode_t mode = inode->i_mode;
81 
82 		error = posix_acl_equiv_mode(acl, &mode);
83 		if (error < 0)
84 			return error;
85 
86 		if (error == 0)
87 			acl = NULL;
88 
89 		if (mode != inode->i_mode) {
90 			inode->i_mode = mode;
91 			mark_inode_dirty(inode);
92 		}
93 	}
94 
95 	if (acl) {
96 		len = posix_acl_to_xattr(&init_user_ns, acl, NULL, 0);
97 		if (len == 0)
98 			return 0;
99 		data = kmalloc(len, GFP_NOFS);
100 		if (data == NULL)
101 			return -ENOMEM;
102 		error = posix_acl_to_xattr(&init_user_ns, acl, data, len);
103 		if (error < 0)
104 			goto out;
105 	} else {
106 		data = NULL;
107 		len = 0;
108 	}
109 
110 	error = __gfs2_xattr_set(inode, name, data, len, 0, GFS2_EATYPE_SYS);
111 	if (error)
112 		goto out;
113 	set_cached_acl(inode, type, acl);
114 out:
115 	kfree(data);
116 	return error;
117 }
118