xref: /kernel/linux/linux-5.10/fs/gfs2/acl.c (revision 8c2ecf20)
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
4 * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
5 */
6
7#include <linux/sched.h>
8#include <linux/slab.h>
9#include <linux/spinlock.h>
10#include <linux/completion.h>
11#include <linux/buffer_head.h>
12#include <linux/xattr.h>
13#include <linux/posix_acl.h>
14#include <linux/posix_acl_xattr.h>
15#include <linux/gfs2_ondisk.h>
16
17#include "gfs2.h"
18#include "incore.h"
19#include "acl.h"
20#include "xattr.h"
21#include "glock.h"
22#include "inode.h"
23#include "meta_io.h"
24#include "quota.h"
25#include "rgrp.h"
26#include "trans.h"
27#include "util.h"
28
29static const char *gfs2_acl_name(int type)
30{
31	switch (type) {
32	case ACL_TYPE_ACCESS:
33		return XATTR_POSIX_ACL_ACCESS;
34	case ACL_TYPE_DEFAULT:
35		return XATTR_POSIX_ACL_DEFAULT;
36	}
37	return NULL;
38}
39
40static struct posix_acl *__gfs2_get_acl(struct inode *inode, int type)
41{
42	struct gfs2_inode *ip = GFS2_I(inode);
43	struct posix_acl *acl;
44	const char *name;
45	char *data;
46	int len;
47
48	if (!ip->i_eattr)
49		return NULL;
50
51	name = gfs2_acl_name(type);
52	len = gfs2_xattr_acl_get(ip, name, &data);
53	if (len <= 0)
54		return ERR_PTR(len);
55	acl = posix_acl_from_xattr(&init_user_ns, data, len);
56	kfree(data);
57	return acl;
58}
59
60struct posix_acl *gfs2_get_acl(struct inode *inode, int type)
61{
62	struct gfs2_inode *ip = GFS2_I(inode);
63	struct gfs2_holder gh;
64	bool need_unlock = false;
65	struct posix_acl *acl;
66
67	if (!gfs2_glock_is_locked_by_me(ip->i_gl)) {
68		int ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED,
69					     LM_FLAG_ANY, &gh);
70		if (ret)
71			return ERR_PTR(ret);
72		need_unlock = true;
73	}
74	acl = __gfs2_get_acl(inode, type);
75	if (need_unlock)
76		gfs2_glock_dq_uninit(&gh);
77	return acl;
78}
79
80int __gfs2_set_acl(struct inode *inode, struct posix_acl *acl, int type)
81{
82	int error;
83	size_t len;
84	char *data;
85	const char *name = gfs2_acl_name(type);
86
87	if (acl) {
88		len = posix_acl_xattr_size(acl->a_count);
89		data = kmalloc(len, GFP_NOFS);
90		if (data == NULL)
91			return -ENOMEM;
92		error = posix_acl_to_xattr(&init_user_ns, acl, data, len);
93		if (error < 0)
94			goto out;
95	} else {
96		data = NULL;
97		len = 0;
98	}
99
100	error = __gfs2_xattr_set(inode, name, data, len, 0, GFS2_EATYPE_SYS);
101	if (error)
102		goto out;
103	set_cached_acl(inode, type, acl);
104out:
105	kfree(data);
106	return error;
107}
108
109int gfs2_set_acl(struct inode *inode, struct posix_acl *acl, int type)
110{
111	struct gfs2_inode *ip = GFS2_I(inode);
112	struct gfs2_holder gh;
113	bool need_unlock = false;
114	int ret;
115	umode_t mode;
116
117	if (acl && acl->a_count > GFS2_ACL_MAX_ENTRIES(GFS2_SB(inode)))
118		return -E2BIG;
119
120	ret = gfs2_qa_get(ip);
121	if (ret)
122		return ret;
123
124	if (!gfs2_glock_is_locked_by_me(ip->i_gl)) {
125		ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh);
126		if (ret)
127			goto out;
128		need_unlock = true;
129	}
130
131	mode = inode->i_mode;
132	if (type == ACL_TYPE_ACCESS && acl) {
133		ret = posix_acl_update_mode(inode, &mode, &acl);
134		if (ret)
135			goto unlock;
136	}
137
138	ret = __gfs2_set_acl(inode, acl, type);
139	if (!ret && mode != inode->i_mode) {
140		inode->i_ctime = current_time(inode);
141		inode->i_mode = mode;
142		mark_inode_dirty(inode);
143	}
144unlock:
145	if (need_unlock)
146		gfs2_glock_dq_uninit(&gh);
147out:
148	gfs2_qa_put(ip);
149	return ret;
150}
151