[linux-block.git] / fs / btrfs / acl.c

/*
 * 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 "ctree.h"
#include "btrfs_inode.h"
#include "xattr.h"

#ifdef CONFIG_FS_POSIX_ACL

static void btrfs_update_cached_acl(struct inode *inode,
				    struct posix_acl **p_acl,
				    struct posix_acl *acl)
{
	spin_lock(&inode->i_lock);
	if (*p_acl && *p_acl != ACL_NOT_CACHED)
		posix_acl_release(*p_acl);
	*p_acl = posix_acl_dup(acl);
	spin_unlock(&inode->i_lock);
}

static struct posix_acl *btrfs_get_acl(struct inode *inode, int type)
{
	int size;
	const char *name;
	char *value = NULL;
	struct posix_acl *acl = NULL, **p_acl;

	switch (type) {
	case ACL_TYPE_ACCESS:
		name = POSIX_ACL_XATTR_ACCESS;
		p_acl = &inode->i_acl;
		break;
	case ACL_TYPE_DEFAULT:
		name = POSIX_ACL_XATTR_DEFAULT;
		p_acl = &inode->i_default_acl;
		break;
	default:
		return ERR_PTR(-EINVAL);
	}

	/* Handle the cached NULL acl case without locking */
	acl = ACCESS_ONCE(*p_acl);
	if (!acl)
		return acl;

	spin_lock(&inode->i_lock);
	acl = *p_acl;
	if (acl != ACL_NOT_CACHED)
		acl = posix_acl_dup(acl);
	spin_unlock(&inode->i_lock);

	if (acl != ACL_NOT_CACHED)
		return acl;

	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(value, size);
			btrfs_update_cached_acl(inode, p_acl, acl);
		}
		kfree(value);
	} else if (size == -ENOENT || size == -ENODATA || size == 0) {
		/* FIXME, who returns -ENOENT?  I think nobody */
		acl = NULL;
		btrfs_update_cached_acl(inode, p_acl, acl);
	} else {
		acl = ERR_PTR(-EIO);
	}

	return acl;
}

static int btrfs_xattr_get_acl(struct inode *inode, int type,
			       void *value, size_t size)
{
	struct posix_acl *acl;
	int ret = 0;

	acl = btrfs_get_acl(inode, type);

	if (IS_ERR(acl))
		return PTR_ERR(acl);
	if (acl == NULL)
		return -ENODATA;
	ret = posix_acl_to_xattr(acl, value, size);
	posix_acl_release(acl);

	return ret;
}

/*
 * Needs to be called with fs_mutex held
 */
static int btrfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
{
	int ret, size = 0;
	const char *name;
	struct posix_acl **p_acl;
	char *value = NULL;
	mode_t mode;

	if (acl) {
		ret = posix_acl_valid(acl);
		if (ret < 0)
			return ret;
		ret = 0;
	}

	switch (type) {
	case ACL_TYPE_ACCESS:
		mode = inode->i_mode;
		ret = posix_acl_equiv_mode(acl, &mode);
		if (ret < 0)
			return ret;
		ret = 0;
		inode->i_mode = mode;
		name = POSIX_ACL_XATTR_ACCESS;
		p_acl = &inode->i_acl;
		break;
	case ACL_TYPE_DEFAULT:
		if (!S_ISDIR(inode->i_mode))
			return acl ? -EINVAL : 0;
		name = POSIX_ACL_XATTR_DEFAULT;
		p_acl = &inode->i_default_acl;
		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(acl, value, size);
		if (ret < 0)
			goto out;
	}

	ret = __btrfs_setxattr(inode, name, value, size, 0);

out:
	kfree(value);

	if (!ret)
		btrfs_update_cached_acl(inode, p_acl, acl);

	return ret;
}

static int btrfs_xattr_set_acl(struct inode *inode, int type,
			       const void *value, size_t size)
{
	int ret = 0;
	struct posix_acl *acl = NULL;

	if (value) {
		acl = posix_acl_from_xattr(value, size);
		if (acl == NULL) {
			value = NULL;
			size = 0;
		} else if (IS_ERR(acl)) {
			return PTR_ERR(acl);
		}
	}

	ret = btrfs_set_acl(inode, acl, type);

	posix_acl_release(acl);

	return ret;
}


static int btrfs_xattr_acl_access_get(struct inode *inode, const char *name,
				      void *value, size_t size)
{
	return btrfs_xattr_get_acl(inode, ACL_TYPE_ACCESS, value, size);
}

static int btrfs_xattr_acl_access_set(struct inode *inode, const char *name,
				      const void *value, size_t size, int flags)
{
	return btrfs_xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size);
}

static int btrfs_xattr_acl_default_get(struct inode *inode, const char *name,
				       void *value, size_t size)
{
	return btrfs_xattr_get_acl(inode, ACL_TYPE_DEFAULT, value, size);
}

static int btrfs_xattr_acl_default_set(struct inode *inode, const char *name,
			       const void *value, size_t size, int flags)
{
	return btrfs_xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size);
}

int btrfs_check_acl(struct inode *inode, int mask)
{
	struct posix_acl *acl;
	int error = -EAGAIN;

	acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS);

	if (IS_ERR(acl))
		return PTR_ERR(acl);
	if (acl) {
		error = posix_acl_permission(inode, acl, mask);
		posix_acl_release(acl);
	}

	return error;
}

/*
 * 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 inode *inode, struct inode *dir)
{
	struct posix_acl *acl = NULL;
	int ret = 0;

	/* this happens with subvols */
	if (!dir)
		return 0;

	if (!S_ISLNK(inode->i_mode)) {
		if (IS_POSIXACL(dir)) {
			acl = btrfs_get_acl(dir, ACL_TYPE_DEFAULT);
			if (IS_ERR(acl))
				return PTR_ERR(acl);
		}

		if (!acl)
			inode->i_mode &= ~current_umask();
	}

	if (IS_POSIXACL(dir) && acl) {
		struct posix_acl *clone;
		mode_t mode;

		if (S_ISDIR(inode->i_mode)) {
			ret = btrfs_set_acl(inode, acl, ACL_TYPE_DEFAULT);
			if (ret)
				goto failed;
		}
		clone = posix_acl_clone(acl, GFP_NOFS);
		ret = -ENOMEM;
		if (!clone)
			goto failed;

		mode = inode->i_mode;
		ret = posix_acl_create_masq(clone, &mode);
		if (ret >= 0) {
			inode->i_mode = mode;
			if (ret > 0) {
				/* we need an acl */
				ret = btrfs_set_acl(inode, clone,
						    ACL_TYPE_ACCESS);
			}
		}
	}
failed:
	posix_acl_release(acl);

	return ret;
}

int btrfs_acl_chmod(struct inode *inode)
{
	struct posix_acl *acl, *clone;
	int ret = 0;

	if (S_ISLNK(inode->i_mode))
		return -EOPNOTSUPP;

	if (!IS_POSIXACL(inode))
		return 0;

	acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS);
	if (IS_ERR(acl) || !acl)
		return PTR_ERR(acl);

	clone = posix_acl_clone(acl, GFP_KERNEL);
	posix_acl_release(acl);
	if (!clone)
		return -ENOMEM;

	ret = posix_acl_chmod_masq(clone, inode->i_mode);
	if (!ret)
		ret = btrfs_set_acl(inode, clone, ACL_TYPE_ACCESS);

	posix_acl_release(clone);

	return ret;
}

struct xattr_handler btrfs_xattr_acl_default_handler = {
	.prefix = POSIX_ACL_XATTR_DEFAULT,
	.get	= btrfs_xattr_acl_default_get,
	.set	= btrfs_xattr_acl_default_set,
};

struct xattr_handler btrfs_xattr_acl_access_handler = {
	.prefix = POSIX_ACL_XATTR_ACCESS,
	.get	= btrfs_xattr_acl_access_get,
	.set	= btrfs_xattr_acl_access_set,
};

#else /* CONFIG_FS_POSIX_ACL */

int btrfs_acl_chmod(struct inode *inode)
{
	return 0;
}

int btrfs_init_acl(struct inode *inode, struct inode *dir)
{
	return 0;
}

#endif /* CONFIG_FS_POSIX_ACL */
Commit	Line	Data
5103e947 JB	1	/*
	2	* Copyright (C) 2007 Red Hat. All rights reserved.
	3	*
	4	* This program is free software; you can redistribute it and/or
	5	* modify it under the terms of the GNU General Public
	6	* License v2 as published by the Free Software Foundation.
	7	*
	8	* This program is distributed in the hope that it will be useful,
	9	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	10	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	11	* General Public License for more details.
	12	*
	13	* You should have received a copy of the GNU General Public
	14	* License along with this program; if not, write to the
	15	* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
	16	* Boston, MA 021110-1307, USA.
	17	*/
	18
	19	#include <linux/fs.h>
	20	#include <linux/string.h>
	21	#include <linux/xattr.h>
	22	#include <linux/posix_acl_xattr.h>
33268eaf	23	#include <linux/posix_acl.h>
c1e32da6	24	#include <linux/sched.h>
33268eaf	25
5103e947	26	#include "ctree.h"
33268eaf	27	#include "btrfs_inode.h"
5103e947	28	#include "xattr.h"
33268eaf	29
eab922ec JB	30	#ifdef CONFIG_FS_POSIX_ACL
eab922ec JB	31
33268eaf JB	32	static void btrfs_update_cached_acl(struct inode *inode,
	33	struct posix_acl **p_acl,
	34	struct posix_acl *acl)
	35	{
	36	spin_lock(&inode->i_lock);
5affd88a	37	if (p_acl && p_acl != ACL_NOT_CACHED)
33268eaf JB	38	posix_acl_release(*p_acl);
	39	*p_acl = posix_acl_dup(acl);
	40	spin_unlock(&inode->i_lock);
	41	}
	42
	43	static struct posix_acl btrfs_get_acl(struct inode inode, int type)
	44	{
95819c05 CH	45	int size;
95819c05 CH	46	const char *name;
33268eaf JB	47	char *value = NULL;
	48	struct posix_acl acl = NULL, *p_acl;
	49
	50	switch (type) {
	51	case ACL_TYPE_ACCESS:
95819c05	52	name = POSIX_ACL_XATTR_ACCESS;
5affd88a	53	p_acl = &inode->i_acl;
33268eaf JB	54	break;
33268eaf JB	55	case ACL_TYPE_DEFAULT:
95819c05	56	name = POSIX_ACL_XATTR_DEFAULT;
5affd88a	57	p_acl = &inode->i_default_acl;
33268eaf JB	58	break;
	59	default:
	60	return ERR_PTR(-EINVAL);
	61	}
	62
7b1a14bb CM	63	/* Handle the cached NULL acl case without locking */
	64	acl = ACCESS_ONCE(*p_acl);
	65	if (!acl)
	66	return acl;
	67
33268eaf	68	spin_lock(&inode->i_lock);
7b1a14bb	69	acl = *p_acl;
5affd88a	70	if (acl != ACL_NOT_CACHED)
7b1a14bb	71	acl = posix_acl_dup(acl);
33268eaf JB	72	spin_unlock(&inode->i_lock);
33268eaf JB	73
5affd88a	74	if (acl != ACL_NOT_CACHED)
33268eaf JB	75	return acl;
33268eaf JB	76
95819c05	77	size = __btrfs_getxattr(inode, name, "", 0);
33268eaf JB	78	if (size > 0) {
	79	value = kzalloc(size, GFP_NOFS);
	80	if (!value)
	81	return ERR_PTR(-ENOMEM);
95819c05	82	size = __btrfs_getxattr(inode, name, value, size);
33268eaf JB	83	if (size > 0) {
	84	acl = posix_acl_from_xattr(value, size);
	85	btrfs_update_cached_acl(inode, p_acl, acl);
	86	}
	87	kfree(value);
7b1a14bb CM	88	} else if (size == -ENOENT \|\| size == -ENODATA \|\| size == 0) {
7b1a14bb CM	89	/* FIXME, who returns -ENOENT? I think nobody */
33268eaf JB	90	acl = NULL;
33268eaf JB	91	btrfs_update_cached_acl(inode, p_acl, acl);
7b1a14bb CM	92	} else {
7b1a14bb CM	93	acl = ERR_PTR(-EIO);
33268eaf JB	94	}
	95
	96	return acl;
	97	}
	98
	99	static int btrfs_xattr_get_acl(struct inode *inode, int type,
	100	void *value, size_t size)
	101	{
	102	struct posix_acl *acl;
	103	int ret = 0;
	104
	105	acl = btrfs_get_acl(inode, type);
	106
	107	if (IS_ERR(acl))
	108	return PTR_ERR(acl);
	109	if (acl == NULL)
	110	return -ENODATA;
	111	ret = posix_acl_to_xattr(acl, value, size);
	112	posix_acl_release(acl);
	113
	114	return ret;
	115	}
	116
	117	/*
	118	* Needs to be called with fs_mutex held
	119	*/
	120	static int btrfs_set_acl(struct inode inode, struct posix_acl acl, int type)
	121	{
95819c05 CH	122	int ret, size = 0;
95819c05 CH	123	const char *name;
33268eaf JB	124	struct posix_acl **p_acl;
	125	char *value = NULL;
	126	mode_t mode;
	127
	128	if (acl) {
	129	ret = posix_acl_valid(acl);
	130	if (ret < 0)
	131	return ret;
	132	ret = 0;
	133	}
	134
	135	switch (type) {
	136	case ACL_TYPE_ACCESS:
	137	mode = inode->i_mode;
	138	ret = posix_acl_equiv_mode(acl, &mode);
	139	if (ret < 0)
	140	return ret;
	141	ret = 0;
	142	inode->i_mode = mode;
95819c05	143	name = POSIX_ACL_XATTR_ACCESS;
5affd88a	144	p_acl = &inode->i_acl;
33268eaf JB	145	break;
	146	case ACL_TYPE_DEFAULT:
	147	if (!S_ISDIR(inode->i_mode))
	148	return acl ? -EINVAL : 0;
95819c05	149	name = POSIX_ACL_XATTR_DEFAULT;
5affd88a	150	p_acl = &inode->i_default_acl;
33268eaf JB	151	break;
	152	default:
	153	return -EINVAL;
	154	}
	155
	156	if (acl) {
	157	size = posix_acl_xattr_size(acl->a_count);
	158	value = kmalloc(size, GFP_NOFS);
	159	if (!value) {
	160	ret = -ENOMEM;
	161	goto out;
	162	}
	163
	164	ret = posix_acl_to_xattr(acl, value, size);
	165	if (ret < 0)
	166	goto out;
	167	}
	168
95819c05	169	ret = __btrfs_setxattr(inode, name, value, size, 0);
33268eaf JB	170
33268eaf JB	171	out:
d397712b	172	kfree(value);
33268eaf JB	173
	174	if (!ret)
	175	btrfs_update_cached_acl(inode, p_acl, acl);
	176
	177	return ret;
	178	}
fb4bc1e0	179
744f52f9 Y	180	static int btrfs_xattr_set_acl(struct inode *inode, int type,
	181	const void *value, size_t size)
	182	{
	183	int ret = 0;
33268eaf	184	struct posix_acl *acl = NULL;
5103e947	185
744f52f9 Y	186	if (value) {
	187	acl = posix_acl_from_xattr(value, size);
	188	if (acl == NULL) {
	189	value = NULL;
	190	size = 0;
	191	} else if (IS_ERR(acl)) {
33268eaf	192	return PTR_ERR(acl);
744f52f9	193	}
744f52f9	194	}
1caf9342	195
33268eaf JB	196	ret = btrfs_set_acl(inode, acl, type);
	197
	198	posix_acl_release(acl);
	199
	200	return ret;
744f52f9	201	}
33268eaf JB	202
33268eaf JB	203
5103e947 JB	204	static int btrfs_xattr_acl_access_get(struct inode inode, const char name,
	205	void *value, size_t size)
	206	{
33268eaf	207	return btrfs_xattr_get_acl(inode, ACL_TYPE_ACCESS, value, size);
5103e947	208	}
33268eaf	209
5103e947 JB	210	static int btrfs_xattr_acl_access_set(struct inode inode, const char name,
	211	const void *value, size_t size, int flags)
	212	{
33268eaf	213	return btrfs_xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size);
5103e947	214	}
33268eaf	215
5103e947 JB	216	static int btrfs_xattr_acl_default_get(struct inode inode, const char name,
	217	void *value, size_t size)
	218	{
33268eaf	219	return btrfs_xattr_get_acl(inode, ACL_TYPE_DEFAULT, value, size);
5103e947	220	}
33268eaf	221
5103e947	222	static int btrfs_xattr_acl_default_set(struct inode inode, const char name,
d397712b	223	const void *value, size_t size, int flags)
5103e947	224	{
33268eaf JB	225	return btrfs_xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size);
	226	}
	227
	228	int btrfs_check_acl(struct inode *inode, int mask)
	229	{
	230	struct posix_acl *acl;
	231	int error = -EAGAIN;
	232
	233	acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS);
	234
	235	if (IS_ERR(acl))
	236	return PTR_ERR(acl);
	237	if (acl) {
	238	error = posix_acl_permission(inode, acl, mask);
	239	posix_acl_release(acl);
	240	}
	241
	242	return error;
	243	}
	244
	245	/*
	246	* btrfs_init_acl is already generally called under fs_mutex, so the locking
	247	* stuff has been fixed to work with that. If the locking stuff changes, we
	248	* need to re-evaluate the acl locking stuff.
	249	*/
	250	int btrfs_init_acl(struct inode inode, struct inode dir)
	251	{
	252	struct posix_acl *acl = NULL;
	253	int ret = 0;
	254
	255	/* this happens with subvols */
	256	if (!dir)
	257	return 0;
	258
	259	if (!S_ISLNK(inode->i_mode)) {
	260	if (IS_POSIXACL(dir)) {
	261	acl = btrfs_get_acl(dir, ACL_TYPE_DEFAULT);
	262	if (IS_ERR(acl))
	263	return PTR_ERR(acl);
	264	}
	265
	266	if (!acl)
ce3b0f8d	267	inode->i_mode &= ~current_umask();
33268eaf JB	268	}
	269
	270	if (IS_POSIXACL(dir) && acl) {
	271	struct posix_acl *clone;
	272	mode_t mode;
	273
	274	if (S_ISDIR(inode->i_mode)) {
	275	ret = btrfs_set_acl(inode, acl, ACL_TYPE_DEFAULT);
	276	if (ret)
	277	goto failed;
	278	}
	279	clone = posix_acl_clone(acl, GFP_NOFS);
	280	ret = -ENOMEM;
	281	if (!clone)
	282	goto failed;
	283
	284	mode = inode->i_mode;
	285	ret = posix_acl_create_masq(clone, &mode);
	286	if (ret >= 0) {
	287	inode->i_mode = mode;
	288	if (ret > 0) {
	289	/* we need an acl */
	290	ret = btrfs_set_acl(inode, clone,
	291	ACL_TYPE_ACCESS);
	292	}
	293	}
	294	}
	295	failed:
	296	posix_acl_release(acl);
	297
	298	return ret;
	299	}
	300
	301	int btrfs_acl_chmod(struct inode *inode)
	302	{
	303	struct posix_acl acl, clone;
	304	int ret = 0;
	305
	306	if (S_ISLNK(inode->i_mode))
	307	return -EOPNOTSUPP;
	308
	309	if (!IS_POSIXACL(inode))
	310	return 0;
	311
	312	acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS);
	313	if (IS_ERR(acl) \|\| !acl)
	314	return PTR_ERR(acl);
	315
	316	clone = posix_acl_clone(acl, GFP_KERNEL);
	317	posix_acl_release(acl);
	318	if (!clone)
	319	return -ENOMEM;
	320
	321	ret = posix_acl_chmod_masq(clone, inode->i_mode);
	322	if (!ret)
	323	ret = btrfs_set_acl(inode, clone, ACL_TYPE_ACCESS);
	324
	325	posix_acl_release(clone);
	326
	327	return ret;
5103e947	328	}
33268eaf	329
5103e947 JB	330	struct xattr_handler btrfs_xattr_acl_default_handler = {
5103e947 JB	331	.prefix = POSIX_ACL_XATTR_DEFAULT,
5103e947 JB	332	.get = btrfs_xattr_acl_default_get,
	333	.set = btrfs_xattr_acl_default_set,
	334	};
	335
	336	struct xattr_handler btrfs_xattr_acl_access_handler = {
	337	.prefix = POSIX_ACL_XATTR_ACCESS,
5103e947 JB	338	.get = btrfs_xattr_acl_access_get,
	339	.set = btrfs_xattr_acl_access_set,
	340	};
eab922ec JB	341
	342	#else /* CONFIG_FS_POSIX_ACL */
	343
	344	int btrfs_acl_chmod(struct inode *inode)
	345	{
	346	return 0;
	347	}
	348
	349	int btrfs_init_acl(struct inode inode, struct inode dir)
	350	{
	351	return 0;
	352	}
	353
eab922ec	354	#endif /* CONFIG_FS_POSIX_ACL */