[linux-2.6-block.git] / fs / xfs / xfs_acl.c

/*
 * Copyright (c) 2008, Christoph Hellwig
 * 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 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would 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 the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
#include "xfs.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_inode.h"
#include "xfs_acl.h"
#include "xfs_attr.h"
#include "xfs_trace.h"
#include <linux/slab.h>
#include <linux/xattr.h>
#include <linux/posix_acl_xattr.h>


/*
 * Locking scheme:
 *  - all ACL updates are protected by inode->i_mutex, which is taken before
 *    calling into this file.
 */

STATIC struct posix_acl *
xfs_acl_from_disk(
	struct xfs_acl	*aclp,
	int		max_entries)
{
	struct posix_acl_entry *acl_e;
	struct posix_acl *acl;
	struct xfs_acl_entry *ace;
	unsigned int count, i;

	count = be32_to_cpu(aclp->acl_cnt);
	if (count > max_entries)
		return ERR_PTR(-EFSCORRUPTED);

	acl = posix_acl_alloc(count, GFP_KERNEL);
	if (!acl)
		return ERR_PTR(-ENOMEM);

	for (i = 0; i < count; i++) {
		acl_e = &acl->a_entries[i];
		ace = &aclp->acl_entry[i];

		/*
		 * The tag is 32 bits on disk and 16 bits in core.
		 *
		 * Because every access to it goes through the core
		 * format first this is not a problem.
		 */
		acl_e->e_tag = be32_to_cpu(ace->ae_tag);
		acl_e->e_perm = be16_to_cpu(ace->ae_perm);

		switch (acl_e->e_tag) {
		case ACL_USER:
			acl_e->e_uid = xfs_uid_to_kuid(be32_to_cpu(ace->ae_id));
			break;
		case ACL_GROUP:
			acl_e->e_gid = xfs_gid_to_kgid(be32_to_cpu(ace->ae_id));
			break;
		case ACL_USER_OBJ:
		case ACL_GROUP_OBJ:
		case ACL_MASK:
		case ACL_OTHER:
			break;
		default:
			goto fail;
		}
	}
	return acl;

fail:
	posix_acl_release(acl);
	return ERR_PTR(-EINVAL);
}

STATIC void
xfs_acl_to_disk(struct xfs_acl *aclp, const struct posix_acl *acl)
{
	const struct posix_acl_entry *acl_e;
	struct xfs_acl_entry *ace;
	int i;

	aclp->acl_cnt = cpu_to_be32(acl->a_count);
	for (i = 0; i < acl->a_count; i++) {
		ace = &aclp->acl_entry[i];
		acl_e = &acl->a_entries[i];

		ace->ae_tag = cpu_to_be32(acl_e->e_tag);
		switch (acl_e->e_tag) {
		case ACL_USER:
			ace->ae_id = cpu_to_be32(xfs_kuid_to_uid(acl_e->e_uid));
			break;
		case ACL_GROUP:
			ace->ae_id = cpu_to_be32(xfs_kgid_to_gid(acl_e->e_gid));
			break;
		default:
			ace->ae_id = cpu_to_be32(ACL_UNDEFINED_ID);
			break;
		}

		ace->ae_perm = cpu_to_be16(acl_e->e_perm);
	}
}

struct posix_acl *
xfs_get_acl(struct inode *inode, int type)
{
	struct xfs_inode *ip = XFS_I(inode);
	struct posix_acl *acl = NULL;
	struct xfs_acl *xfs_acl;
	unsigned char *ea_name;
	int error;
	int len;

	trace_xfs_get_acl(ip);

	switch (type) {
	case ACL_TYPE_ACCESS:
		ea_name = SGI_ACL_FILE;
		break;
	case ACL_TYPE_DEFAULT:
		ea_name = SGI_ACL_DEFAULT;
		break;
	default:
		BUG();
	}

	/*
	 * If we have a cached ACLs value just return it, not need to
	 * go out to the disk.
	 */
	len = XFS_ACL_MAX_SIZE(ip->i_mount);
	xfs_acl = kmem_zalloc_large(len, KM_SLEEP);
	if (!xfs_acl)
		return ERR_PTR(-ENOMEM);

	error = xfs_attr_get(ip, ea_name, (unsigned char *)xfs_acl,
							&len, ATTR_ROOT);
	if (error) {
		/*
		 * If the attribute doesn't exist make sure we have a negative
		 * cache entry, for any other error assume it is transient and
		 * leave the cache entry as ACL_NOT_CACHED.
		 */
		if (error == -ENOATTR)
			goto out_update_cache;
		goto out;
	}

	acl = xfs_acl_from_disk(xfs_acl, XFS_ACL_MAX_ENTRIES(ip->i_mount));
	if (IS_ERR(acl))
		goto out;

out_update_cache:
	set_cached_acl(inode, type, acl);
out:
	kmem_free(xfs_acl);
	return acl;
}

STATIC int
__xfs_set_acl(struct inode *inode, int type, struct posix_acl *acl)
{
	struct xfs_inode *ip = XFS_I(inode);
	unsigned char *ea_name;
	int error;

	switch (type) {
	case ACL_TYPE_ACCESS:
		ea_name = SGI_ACL_FILE;
		break;
	case ACL_TYPE_DEFAULT:
		if (!S_ISDIR(inode->i_mode))
			return acl ? -EACCES : 0;
		ea_name = SGI_ACL_DEFAULT;
		break;
	default:
		return -EINVAL;
	}

	if (acl) {
		struct xfs_acl *xfs_acl;
		int len = XFS_ACL_MAX_SIZE(ip->i_mount);

		xfs_acl = kmem_zalloc_large(len, KM_SLEEP);
		if (!xfs_acl)
			return -ENOMEM;

		xfs_acl_to_disk(xfs_acl, acl);

		/* subtract away the unused acl entries */
		len -= sizeof(struct xfs_acl_entry) *
			 (XFS_ACL_MAX_ENTRIES(ip->i_mount) - acl->a_count);

		error = xfs_attr_set(ip, ea_name, (unsigned char *)xfs_acl,
				len, ATTR_ROOT);

		kmem_free(xfs_acl);
	} else {
		/*
		 * A NULL ACL argument means we want to remove the ACL.
		 */
		error = xfs_attr_remove(ip, ea_name, ATTR_ROOT);

		/*
		 * If the attribute didn't exist to start with that's fine.
		 */
		if (error == -ENOATTR)
			error = 0;
	}

	if (!error)
		set_cached_acl(inode, type, acl);
	return error;
}

static int
xfs_set_mode(struct inode *inode, umode_t mode)
{
	int error = 0;

	if (mode != inode->i_mode) {
		struct iattr iattr;

		iattr.ia_valid = ATTR_MODE | ATTR_CTIME;
		iattr.ia_mode = mode;
		iattr.ia_ctime = current_fs_time(inode->i_sb);

		error = xfs_setattr_nonsize(XFS_I(inode), &iattr, XFS_ATTR_NOACL);
	}

	return error;
}

static int
xfs_acl_exists(struct inode *inode, unsigned char *name)
{
	int len = XFS_ACL_MAX_SIZE(XFS_M(inode->i_sb));

	return (xfs_attr_get(XFS_I(inode), name, NULL, &len,
			    ATTR_ROOT|ATTR_KERNOVAL) == 0);
}

int
posix_acl_access_exists(struct inode *inode)
{
	return xfs_acl_exists(inode, SGI_ACL_FILE);
}

int
posix_acl_default_exists(struct inode *inode)
{
	if (!S_ISDIR(inode->i_mode))
		return 0;
	return xfs_acl_exists(inode, SGI_ACL_DEFAULT);
}

int
xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
{
	int error = 0;

	if (!acl)
		goto set_acl;

	error = -E2BIG;
	if (acl->a_count > XFS_ACL_MAX_ENTRIES(XFS_M(inode->i_sb)))
		return error;

	if (type == ACL_TYPE_ACCESS) {
		umode_t mode = inode->i_mode;
		error = posix_acl_equiv_mode(acl, &mode);

		if (error <= 0) {
			acl = NULL;

			if (error < 0)
				return error;
		}

		error = xfs_set_mode(inode, mode);
		if (error)
			return error;
	}

 set_acl:
	return __xfs_set_acl(inode, type, acl);
}
Commit	Line	Data
ef14f0c1 CH	1	/*
	2	* Copyright (c) 2008, Christoph Hellwig
	3	* All Rights Reserved.
	4	*
	5	* This program is free software; you can redistribute it and/or
	6	* modify it under the terms of the GNU General Public License as
	7	* published by the Free Software Foundation.
	8	*
	9	* This program is distributed in the hope that it would be useful,
	10	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	12	* GNU General Public License for more details.
	13	*
	14	* You should have received a copy of the GNU General Public License
	15	* along with this program; if not, write the Free Software Foundation,
	16	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
	17	*/
	18	#include "xfs.h"
a4fbe6ab	19	#include "xfs_format.h"
69432832	20	#include "xfs_log_format.h"
7fd36c44	21	#include "xfs_trans_resv.h"
0a8aa193	22	#include "xfs_mount.h"
a4fbe6ab DC	23	#include "xfs_inode.h"
	24	#include "xfs_acl.h"
	25	#include "xfs_attr.h"
0b1b213f	26	#include "xfs_trace.h"
5a0e3ad6	27	#include <linux/slab.h>
ef14f0c1 CH	28	#include <linux/xattr.h>
	29	#include <linux/posix_acl_xattr.h>
	30
	31
ef14f0c1 CH	32	/*
	33	* Locking scheme:
	34	* - all ACL updates are protected by inode->i_mutex, which is taken before
	35	* calling into this file.
ef14f0c1 CH	36	*/
	37
	38	STATIC struct posix_acl *
0a8aa193 DC	39	xfs_acl_from_disk(
	40	struct xfs_acl *aclp,
	41	int max_entries)
ef14f0c1 CH	42	{
	43	struct posix_acl_entry *acl_e;
	44	struct posix_acl *acl;
	45	struct xfs_acl_entry *ace;
093019cf	46	unsigned int count, i;
ef14f0c1 CH	47
ef14f0c1 CH	48	count = be32_to_cpu(aclp->acl_cnt);
0a8aa193	49	if (count > max_entries)
fa8b18ed	50	return ERR_PTR(-EFSCORRUPTED);
ef14f0c1 CH	51
	52	acl = posix_acl_alloc(count, GFP_KERNEL);
	53	if (!acl)
	54	return ERR_PTR(-ENOMEM);
	55
	56	for (i = 0; i < count; i++) {
	57	acl_e = &acl->a_entries[i];
	58	ace = &aclp->acl_entry[i];
	59
	60	/*
	61	* The tag is 32 bits on disk and 16 bits in core.
	62	*
	63	* Because every access to it goes through the core
	64	* format first this is not a problem.
	65	*/
	66	acl_e->e_tag = be32_to_cpu(ace->ae_tag);
	67	acl_e->e_perm = be16_to_cpu(ace->ae_perm);
	68
	69	switch (acl_e->e_tag) {
	70	case ACL_USER:
288bbe0e DE	71	acl_e->e_uid = xfs_uid_to_kuid(be32_to_cpu(ace->ae_id));
288bbe0e DE	72	break;
ef14f0c1	73	case ACL_GROUP:
288bbe0e	74	acl_e->e_gid = xfs_gid_to_kgid(be32_to_cpu(ace->ae_id));
ef14f0c1 CH	75	break;
	76	case ACL_USER_OBJ:
	77	case ACL_GROUP_OBJ:
	78	case ACL_MASK:
	79	case ACL_OTHER:
ef14f0c1 CH	80	break;
	81	default:
	82	goto fail;
	83	}
	84	}
	85	return acl;
	86
	87	fail:
	88	posix_acl_release(acl);
	89	return ERR_PTR(-EINVAL);
	90	}
	91
	92	STATIC void
	93	xfs_acl_to_disk(struct xfs_acl aclp, const struct posix_acl acl)
	94	{
	95	const struct posix_acl_entry *acl_e;
	96	struct xfs_acl_entry *ace;
	97	int i;
	98
	99	aclp->acl_cnt = cpu_to_be32(acl->a_count);
	100	for (i = 0; i < acl->a_count; i++) {
	101	ace = &aclp->acl_entry[i];
	102	acl_e = &acl->a_entries[i];
	103
	104	ace->ae_tag = cpu_to_be32(acl_e->e_tag);
288bbe0e DE	105	switch (acl_e->e_tag) {
	106	case ACL_USER:
	107	ace->ae_id = cpu_to_be32(xfs_kuid_to_uid(acl_e->e_uid));
	108	break;
	109	case ACL_GROUP:
	110	ace->ae_id = cpu_to_be32(xfs_kgid_to_gid(acl_e->e_gid));
	111	break;
	112	default:
	113	ace->ae_id = cpu_to_be32(ACL_UNDEFINED_ID);
	114	break;
	115	}
	116
ef14f0c1 CH	117	ace->ae_perm = cpu_to_be16(acl_e->e_perm);
	118	}
	119	}
	120
ef14f0c1 CH	121	struct posix_acl *
	122	xfs_get_acl(struct inode *inode, int type)
	123	{
	124	struct xfs_inode *ip = XFS_I(inode);
2401dc29	125	struct posix_acl *acl = NULL;
ef14f0c1	126	struct xfs_acl *xfs_acl;
a9273ca5	127	unsigned char *ea_name;
ef14f0c1	128	int error;
0a8aa193	129	int len;
ef14f0c1	130
4e34e719 CH	131	trace_xfs_get_acl(ip);
4e34e719 CH	132
ef14f0c1 CH	133	switch (type) {
	134	case ACL_TYPE_ACCESS:
	135	ea_name = SGI_ACL_FILE;
ef14f0c1 CH	136	break;
	137	case ACL_TYPE_DEFAULT:
	138	ea_name = SGI_ACL_DEFAULT;
ef14f0c1 CH	139	break;
ef14f0c1 CH	140	default:
1cbd20d8	141	BUG();
ef14f0c1 CH	142	}
ef14f0c1 CH	143
ef14f0c1 CH	144	/*
	145	* If we have a cached ACLs value just return it, not need to
	146	* go out to the disk.
	147	*/
0a8aa193	148	len = XFS_ACL_MAX_SIZE(ip->i_mount);
fdd3ccee DC	149	xfs_acl = kmem_zalloc_large(len, KM_SLEEP);
	150	if (!xfs_acl)
	151	return ERR_PTR(-ENOMEM);
ef14f0c1	152
2451337d	153	error = xfs_attr_get(ip, ea_name, (unsigned char *)xfs_acl,
a9273ca5	154	&len, ATTR_ROOT);
ef14f0c1 CH	155	if (error) {
	156	/*
	157	* If the attribute doesn't exist make sure we have a negative
	158	* cache entry, for any other error assume it is transient and
1cbd20d8	159	* leave the cache entry as ACL_NOT_CACHED.
ef14f0c1	160	*/
2401dc29	161	if (error == -ENOATTR)
ef14f0c1	162	goto out_update_cache;
ef14f0c1 CH	163	goto out;
	164	}
	165
0a8aa193	166	acl = xfs_acl_from_disk(xfs_acl, XFS_ACL_MAX_ENTRIES(ip->i_mount));
ef14f0c1 CH	167	if (IS_ERR(acl))
	168	goto out;
	169
2dc164f2	170	out_update_cache:
1cbd20d8	171	set_cached_acl(inode, type, acl);
2dc164f2	172	out:
fdd3ccee	173	kmem_free(xfs_acl);
ef14f0c1 CH	174	return acl;
	175	}
	176
	177	STATIC int
2401dc29	178	__xfs_set_acl(struct inode inode, int type, struct posix_acl acl)
ef14f0c1 CH	179	{
ef14f0c1 CH	180	struct xfs_inode *ip = XFS_I(inode);
a9273ca5	181	unsigned char *ea_name;
ef14f0c1 CH	182	int error;
ef14f0c1 CH	183
ef14f0c1 CH	184	switch (type) {
	185	case ACL_TYPE_ACCESS:
	186	ea_name = SGI_ACL_FILE;
ef14f0c1 CH	187	break;
	188	case ACL_TYPE_DEFAULT:
	189	if (!S_ISDIR(inode->i_mode))
	190	return acl ? -EACCES : 0;
	191	ea_name = SGI_ACL_DEFAULT;
ef14f0c1 CH	192	break;
	193	default:
	194	return -EINVAL;
	195	}
	196
	197	if (acl) {
	198	struct xfs_acl *xfs_acl;
0a8aa193	199	int len = XFS_ACL_MAX_SIZE(ip->i_mount);
ef14f0c1	200
fdd3ccee DC	201	xfs_acl = kmem_zalloc_large(len, KM_SLEEP);
	202	if (!xfs_acl)
	203	return -ENOMEM;
ef14f0c1 CH	204
ef14f0c1 CH	205	xfs_acl_to_disk(xfs_acl, acl);
0a8aa193 DC	206
	207	/* subtract away the unused acl entries */
	208	len -= sizeof(struct xfs_acl_entry) *
	209	(XFS_ACL_MAX_ENTRIES(ip->i_mount) - acl->a_count);
ef14f0c1	210
2451337d	211	error = xfs_attr_set(ip, ea_name, (unsigned char *)xfs_acl,
ef14f0c1 CH	212	len, ATTR_ROOT);
ef14f0c1 CH	213
fdd3ccee	214	kmem_free(xfs_acl);
ef14f0c1 CH	215	} else {
	216	/*
	217	* A NULL ACL argument means we want to remove the ACL.
	218	*/
2451337d	219	error = xfs_attr_remove(ip, ea_name, ATTR_ROOT);
ef14f0c1 CH	220
	221	/*
	222	* If the attribute didn't exist to start with that's fine.
	223	*/
	224	if (error == -ENOATTR)
	225	error = 0;
	226	}
	227
	228	if (!error)
1cbd20d8	229	set_cached_acl(inode, type, acl);
ef14f0c1 CH	230	return error;
	231	}
	232
ef14f0c1	233	static int
d3fb6120	234	xfs_set_mode(struct inode *inode, umode_t mode)
ef14f0c1 CH	235	{
	236	int error = 0;
	237
	238	if (mode != inode->i_mode) {
	239	struct iattr iattr;
	240
d6d59bad	241	iattr.ia_valid = ATTR_MODE \| ATTR_CTIME;
ef14f0c1	242	iattr.ia_mode = mode;
d6d59bad	243	iattr.ia_ctime = current_fs_time(inode->i_sb);
ef14f0c1	244
2451337d	245	error = xfs_setattr_nonsize(XFS_I(inode), &iattr, XFS_ATTR_NOACL);
ef14f0c1 CH	246	}
	247
	248	return error;
	249	}
	250
	251	static int
a9273ca5	252	xfs_acl_exists(struct inode inode, unsigned char name)
ef14f0c1	253	{
0a8aa193	254	int len = XFS_ACL_MAX_SIZE(XFS_M(inode->i_sb));
ef14f0c1 CH	255
	256	return (xfs_attr_get(XFS_I(inode), name, NULL, &len,
	257	ATTR_ROOT\|ATTR_KERNOVAL) == 0);
	258	}
	259
	260	int
	261	posix_acl_access_exists(struct inode *inode)
	262	{
	263	return xfs_acl_exists(inode, SGI_ACL_FILE);
	264	}
	265
	266	int
	267	posix_acl_default_exists(struct inode *inode)
	268	{
	269	if (!S_ISDIR(inode->i_mode))
	270	return 0;
	271	return xfs_acl_exists(inode, SGI_ACL_DEFAULT);
	272	}
	273
ef14f0c1	274	int
2401dc29	275	xfs_set_acl(struct inode inode, struct posix_acl acl, int type)
ef14f0c1	276	{
431547b3	277	int error = 0;
ef14f0c1	278
2401dc29	279	if (!acl)
ef14f0c1 CH	280	goto set_acl;
ef14f0c1 CH	281
4ae69fea	282	error = -E2BIG;
0a8aa193	283	if (acl->a_count > XFS_ACL_MAX_ENTRIES(XFS_M(inode->i_sb)))
2401dc29	284	return error;
ef14f0c1 CH	285
ef14f0c1 CH	286	if (type == ACL_TYPE_ACCESS) {
d6952123	287	umode_t mode = inode->i_mode;
ef14f0c1 CH	288	error = posix_acl_equiv_mode(acl, &mode);
	289
	290	if (error <= 0) {
ef14f0c1 CH	291	acl = NULL;
	292
	293	if (error < 0)
	294	return error;
	295	}
	296
	297	error = xfs_set_mode(inode, mode);
	298	if (error)
2401dc29	299	return error;
ef14f0c1 CH	300	}
	301
	302	set_acl:
2401dc29	303	return __xfs_set_acl(inode, type, acl);
ef14f0c1	304	}