[linux.git] / fs / ext2 / acl.c

/*
 * linux/fs/ext2/acl.c
 *
 * Copyright (C) 2001-2003 Andreas Gruenbacher, <[email protected]>
 */

#include <linux/capability.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include "ext2.h"
#include "xattr.h"
#include "acl.h"

/*
 * Convert from filesystem to in-memory representation.
 */
static struct posix_acl *
ext2_acl_from_disk(const void *value, size_t size)
{
	const char *end = (char *)value + size;
	int n, count;
	struct posix_acl *acl;

	if (!value)
		return NULL;
	if (size < sizeof(ext2_acl_header))
		 return ERR_PTR(-EINVAL);
	if (((ext2_acl_header *)value)->a_version !=
	    cpu_to_le32(EXT2_ACL_VERSION))
		return ERR_PTR(-EINVAL);
	value = (char *)value + sizeof(ext2_acl_header);
	count = ext2_acl_count(size);
	if (count < 0)
		return ERR_PTR(-EINVAL);
	if (count == 0)
		return NULL;
	acl = posix_acl_alloc(count, GFP_KERNEL);
	if (!acl)
		return ERR_PTR(-ENOMEM);
	for (n=0; n < count; n++) {
		ext2_acl_entry *entry =
			(ext2_acl_entry *)value;
		if ((char *)value + sizeof(ext2_acl_entry_short) > end)
			goto fail;
		acl->a_entries[n].e_tag  = le16_to_cpu(entry->e_tag);
		acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
		switch(acl->a_entries[n].e_tag) {
			case ACL_USER_OBJ:
			case ACL_GROUP_OBJ:
			case ACL_MASK:
			case ACL_OTHER:
				value = (char *)value +
					sizeof(ext2_acl_entry_short);
				acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
				break;

			case ACL_USER:
			case ACL_GROUP:
				value = (char *)value + sizeof(ext2_acl_entry);
				if ((char *)value > end)
					goto fail;
				acl->a_entries[n].e_id =
					le32_to_cpu(entry->e_id);
				break;

			default:
				goto fail;
		}
	}
	if (value != end)
		goto fail;
	return acl;

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

/*
 * Convert from in-memory to filesystem representation.
 */
static void *
ext2_acl_to_disk(const struct posix_acl *acl, size_t *size)
{
	ext2_acl_header *ext_acl;
	char *e;
	size_t n;

	*size = ext2_acl_size(acl->a_count);
	ext_acl = kmalloc(sizeof(ext2_acl_header) + acl->a_count *
			sizeof(ext2_acl_entry), GFP_KERNEL);
	if (!ext_acl)
		return ERR_PTR(-ENOMEM);
	ext_acl->a_version = cpu_to_le32(EXT2_ACL_VERSION);
	e = (char *)ext_acl + sizeof(ext2_acl_header);
	for (n=0; n < acl->a_count; n++) {
		ext2_acl_entry *entry = (ext2_acl_entry *)e;
		entry->e_tag  = cpu_to_le16(acl->a_entries[n].e_tag);
		entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
		switch(acl->a_entries[n].e_tag) {
			case ACL_USER:
			case ACL_GROUP:
				entry->e_id =
					cpu_to_le32(acl->a_entries[n].e_id);
				e += sizeof(ext2_acl_entry);
				break;

			case ACL_USER_OBJ:
			case ACL_GROUP_OBJ:
			case ACL_MASK:
			case ACL_OTHER:
				e += sizeof(ext2_acl_entry_short);
				break;

			default:
				goto fail;
		}
	}
	return (char *)ext_acl;

fail:
	kfree(ext_acl);
	return ERR_PTR(-EINVAL);
}

/*
 * inode->i_mutex: don't care
 */
static struct posix_acl *
ext2_get_acl(struct inode *inode, int type)
{
	int name_index;
	char *value = NULL;
	struct posix_acl *acl;
	int retval;

	if (!test_opt(inode->i_sb, POSIX_ACL))
		return NULL;

	acl = get_cached_acl(inode, type);
	if (acl != ACL_NOT_CACHED)
		return acl;

	switch (type) {
	case ACL_TYPE_ACCESS:
		name_index = EXT2_XATTR_INDEX_POSIX_ACL_ACCESS;
		break;
	case ACL_TYPE_DEFAULT:
		name_index = EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT;
		break;
	default:
		BUG();
	}
	retval = ext2_xattr_get(inode, name_index, "", NULL, 0);
	if (retval > 0) {
		value = kmalloc(retval, GFP_KERNEL);
		if (!value)
			return ERR_PTR(-ENOMEM);
		retval = ext2_xattr_get(inode, name_index, "", value, retval);
	}
	if (retval > 0)
		acl = ext2_acl_from_disk(value, retval);
	else if (retval == -ENODATA || retval == -ENOSYS)
		acl = NULL;
	else
		acl = ERR_PTR(retval);
	kfree(value);

	if (!IS_ERR(acl))
		set_cached_acl(inode, type, acl);

	return acl;
}

/*
 * inode->i_mutex: down
 */
static int
ext2_set_acl(struct inode *inode, int type, struct posix_acl *acl)
{
	int name_index;
	void *value = NULL;
	size_t size = 0;
	int error;

	if (S_ISLNK(inode->i_mode))
		return -EOPNOTSUPP;
	if (!test_opt(inode->i_sb, POSIX_ACL))
		return 0;

	switch(type) {
		case ACL_TYPE_ACCESS:
			name_index = EXT2_XATTR_INDEX_POSIX_ACL_ACCESS;
			if (acl) {
				mode_t mode = inode->i_mode;
				error = posix_acl_equiv_mode(acl, &mode);
				if (error < 0)
					return error;
				else {
					inode->i_mode = mode;
					mark_inode_dirty(inode);
					if (error == 0)
						acl = NULL;
				}
			}
			break;

		case ACL_TYPE_DEFAULT:
			name_index = EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT;
			if (!S_ISDIR(inode->i_mode))
				return acl ? -EACCES : 0;
			break;

		default:
			return -EINVAL;
	}
 	if (acl) {
		value = ext2_acl_to_disk(acl, &size);
		if (IS_ERR(value))
			return (int)PTR_ERR(value);
	}

	error = ext2_xattr_set(inode, name_index, "", value, size, 0);

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

static int
ext2_check_acl(struct inode *inode, int mask)
{
	struct posix_acl *acl = ext2_get_acl(inode, ACL_TYPE_ACCESS);

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

	return -EAGAIN;
}

int
ext2_permission(struct inode *inode, int mask)
{
	return generic_permission(inode, mask, ext2_check_acl);
}

/*
 * Initialize the ACLs of a new inode. Called from ext2_new_inode.
 *
 * dir->i_mutex: down
 * inode->i_mutex: up (access to inode is still exclusive)
 */
int
ext2_init_acl(struct inode *inode, struct inode *dir)
{
	struct posix_acl *acl = NULL;
	int error = 0;

	if (!S_ISLNK(inode->i_mode)) {
		if (test_opt(dir->i_sb, POSIX_ACL)) {
			acl = ext2_get_acl(dir, ACL_TYPE_DEFAULT);
			if (IS_ERR(acl))
				return PTR_ERR(acl);
		}
		if (!acl)
			inode->i_mode &= ~current_umask();
	}
	if (test_opt(inode->i_sb, POSIX_ACL) && acl) {
               struct posix_acl *clone;
	       mode_t mode;

		if (S_ISDIR(inode->i_mode)) {
			error = ext2_set_acl(inode, ACL_TYPE_DEFAULT, acl);
			if (error)
				goto cleanup;
		}
		clone = posix_acl_clone(acl, GFP_KERNEL);
		error = -ENOMEM;
		if (!clone)
			goto cleanup;
		mode = inode->i_mode;
		error = posix_acl_create_masq(clone, &mode);
		if (error >= 0) {
			inode->i_mode = mode;
			if (error > 0) {
				/* This is an extended ACL */
				error = ext2_set_acl(inode,
						     ACL_TYPE_ACCESS, clone);
			}
		}
		posix_acl_release(clone);
	}
cleanup:
       posix_acl_release(acl);
       return error;
}

/*
 * Does chmod for an inode that may have an Access Control List. The
 * inode->i_mode field must be updated to the desired value by the caller
 * before calling this function.
 * Returns 0 on success, or a negative error number.
 *
 * We change the ACL rather than storing some ACL entries in the file
 * mode permission bits (which would be more efficient), because that
 * would break once additional permissions (like  ACL_APPEND, ACL_DELETE
 * for directories) are added. There are no more bits available in the
 * file mode.
 *
 * inode->i_mutex: down
 */
int
ext2_acl_chmod(struct inode *inode)
{
	struct posix_acl *acl, *clone;
        int error;

	if (!test_opt(inode->i_sb, POSIX_ACL))
		return 0;
	if (S_ISLNK(inode->i_mode))
		return -EOPNOTSUPP;
	acl = ext2_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;
	error = posix_acl_chmod_masq(clone, inode->i_mode);
	if (!error)
		error = ext2_set_acl(inode, ACL_TYPE_ACCESS, clone);
	posix_acl_release(clone);
	return error;
}

/*
 * Extended attribut handlers
 */
static size_t
ext2_xattr_list_acl_access(struct inode *inode, char *list, size_t list_size,
			   const char *name, size_t name_len)
{
	const size_t size = sizeof(POSIX_ACL_XATTR_ACCESS);

	if (!test_opt(inode->i_sb, POSIX_ACL))
		return 0;
	if (list && size <= list_size)
		memcpy(list, POSIX_ACL_XATTR_ACCESS, size);
	return size;
}

static size_t
ext2_xattr_list_acl_default(struct inode *inode, char *list, size_t list_size,
			    const char *name, size_t name_len)
{
	const size_t size = sizeof(POSIX_ACL_XATTR_DEFAULT);

	if (!test_opt(inode->i_sb, POSIX_ACL))
		return 0;
	if (list && size <= list_size)
		memcpy(list, POSIX_ACL_XATTR_DEFAULT, size);
	return size;
}

static int
ext2_xattr_get_acl(struct inode *inode, int type, void *buffer, size_t size)
{
	struct posix_acl *acl;
	int error;

	if (!test_opt(inode->i_sb, POSIX_ACL))
		return -EOPNOTSUPP;

	acl = ext2_get_acl(inode, type);
	if (IS_ERR(acl))
		return PTR_ERR(acl);
	if (acl == NULL)
		return -ENODATA;
	error = posix_acl_to_xattr(acl, buffer, size);
	posix_acl_release(acl);

	return error;
}

static int
ext2_xattr_get_acl_access(struct inode *inode, const char *name,
			  void *buffer, size_t size)
{
	if (strcmp(name, "") != 0)
		return -EINVAL;
	return ext2_xattr_get_acl(inode, ACL_TYPE_ACCESS, buffer, size);
}

static int
ext2_xattr_get_acl_default(struct inode *inode, const char *name,
			   void *buffer, size_t size)
{
	if (strcmp(name, "") != 0)
		return -EINVAL;
	return ext2_xattr_get_acl(inode, ACL_TYPE_DEFAULT, buffer, size);
}

static int
ext2_xattr_set_acl(struct inode *inode, int type, const void *value,
		   size_t size)
{
	struct posix_acl *acl;
	int error;

	if (!test_opt(inode->i_sb, POSIX_ACL))
		return -EOPNOTSUPP;
	if (!is_owner_or_cap(inode))
		return -EPERM;

	if (value) {
		acl = posix_acl_from_xattr(value, size);
		if (IS_ERR(acl))
			return PTR_ERR(acl);
		else if (acl) {
			error = posix_acl_valid(acl);
			if (error)
				goto release_and_out;
		}
	} else
		acl = NULL;

	error = ext2_set_acl(inode, type, acl);

release_and_out:
	posix_acl_release(acl);
	return error;
}

static int
ext2_xattr_set_acl_access(struct inode *inode, const char *name,
			  const void *value, size_t size, int flags)
{
	if (strcmp(name, "") != 0)
		return -EINVAL;
	return ext2_xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size);
}

static int
ext2_xattr_set_acl_default(struct inode *inode, const char *name,
			   const void *value, size_t size, int flags)
{
	if (strcmp(name, "") != 0)
		return -EINVAL;
	return ext2_xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size);
}

struct xattr_handler ext2_xattr_acl_access_handler = {
	.prefix	= POSIX_ACL_XATTR_ACCESS,
	.list	= ext2_xattr_list_acl_access,
	.get	= ext2_xattr_get_acl_access,
	.set	= ext2_xattr_set_acl_access,
};

struct xattr_handler ext2_xattr_acl_default_handler = {
	.prefix	= POSIX_ACL_XATTR_DEFAULT,
	.list	= ext2_xattr_list_acl_default,
	.get	= ext2_xattr_get_acl_default,
	.set	= ext2_xattr_set_acl_default,
};
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/fs/ext2/acl.c
	3	*
	4	* Copyright (C) 2001-2003 Andreas Gruenbacher, <[email protected]>
	5	*/
	6
16f7e0fe	7	#include <linux/capability.h>
1da177e4 LT	8	#include <linux/init.h>
	9	#include <linux/sched.h>
	10	#include <linux/slab.h>
	11	#include <linux/fs.h>
	12	#include "ext2.h"
	13	#include "xattr.h"
	14	#include "acl.h"
	15
	16	/*
	17	* Convert from filesystem to in-memory representation.
	18	*/
	19	static struct posix_acl *
	20	ext2_acl_from_disk(const void *value, size_t size)
	21	{
	22	const char end = (char )value + size;
	23	int n, count;
	24	struct posix_acl *acl;
	25
	26	if (!value)
	27	return NULL;
	28	if (size < sizeof(ext2_acl_header))
	29	return ERR_PTR(-EINVAL);
	30	if (((ext2_acl_header *)value)->a_version !=
	31	cpu_to_le32(EXT2_ACL_VERSION))
	32	return ERR_PTR(-EINVAL);
	33	value = (char *)value + sizeof(ext2_acl_header);
	34	count = ext2_acl_count(size);
	35	if (count < 0)
	36	return ERR_PTR(-EINVAL);
	37	if (count == 0)
	38	return NULL;
	39	acl = posix_acl_alloc(count, GFP_KERNEL);
	40	if (!acl)
	41	return ERR_PTR(-ENOMEM);
	42	for (n=0; n < count; n++) {
	43	ext2_acl_entry *entry =
	44	(ext2_acl_entry *)value;
	45	if ((char *)value + sizeof(ext2_acl_entry_short) > end)
	46	goto fail;
	47	acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag);
	48	acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
	49	switch(acl->a_entries[n].e_tag) {
	50	case ACL_USER_OBJ:
	51	case ACL_GROUP_OBJ:
	52	case ACL_MASK:
	53	case ACL_OTHER:
	54	value = (char *)value +
	55	sizeof(ext2_acl_entry_short);
	56	acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
	57	break;
	58
	59	case ACL_USER:
	60	case ACL_GROUP:
	61	value = (char *)value + sizeof(ext2_acl_entry);
	62	if ((char *)value > end)
	63	goto fail;
	64	acl->a_entries[n].e_id =
	65	le32_to_cpu(entry->e_id);
	66	break;
	67
	68	default:
	69	goto fail;
	70	}
	71	}
72	if (value != end)
73	goto fail;
74	return acl;
75
76	fail:
77	posix_acl_release(acl);
78	return ERR_PTR(-EINVAL);
79	}
80
81	/*
82	* Convert from in-memory to filesystem representation.
83	*/
84	static void *
85	ext2_acl_to_disk(const struct posix_acl acl, size_t size)
86	{
87	ext2_acl_header *ext_acl;
88	char *e;
89	size_t n;
90
91	*size = ext2_acl_size(acl->a_count);
f52720ca PI	92	ext_acl = kmalloc(sizeof(ext2_acl_header) + acl->a_count *
f52720ca PI	93	sizeof(ext2_acl_entry), GFP_KERNEL);
1da177e4 LT	94	if (!ext_acl)
	95	return ERR_PTR(-ENOMEM);
	96	ext_acl->a_version = cpu_to_le32(EXT2_ACL_VERSION);
	97	e = (char *)ext_acl + sizeof(ext2_acl_header);
	98	for (n=0; n < acl->a_count; n++) {
	99	ext2_acl_entry entry = (ext2_acl_entry )e;
	100	entry->e_tag = cpu_to_le16(acl->a_entries[n].e_tag);
	101	entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
	102	switch(acl->a_entries[n].e_tag) {
	103	case ACL_USER:
	104	case ACL_GROUP:
	105	entry->e_id =
	106	cpu_to_le32(acl->a_entries[n].e_id);
	107	e += sizeof(ext2_acl_entry);
	108	break;
	109
	110	case ACL_USER_OBJ:
	111	case ACL_GROUP_OBJ:
	112	case ACL_MASK:
	113	case ACL_OTHER:
	114	e += sizeof(ext2_acl_entry_short);
	115	break;
	116
	117	default:
	118	goto fail;
	119	}
	120	}
	121	return (char *)ext_acl;
	122
	123	fail:
	124	kfree(ext_acl);
	125	return ERR_PTR(-EINVAL);
	126	}
	127
1da177e4	128	/*
1b1dcc1b	129	* inode->i_mutex: don't care
1da177e4 LT	130	*/
	131	static struct posix_acl *
	132	ext2_get_acl(struct inode *inode, int type)
	133	{
1da177e4 LT	134	int name_index;
	135	char *value = NULL;
	136	struct posix_acl *acl;
	137	int retval;
	138
	139	if (!test_opt(inode->i_sb, POSIX_ACL))
	140	return NULL;
	141
073aaa1b AV	142	acl = get_cached_acl(inode, type);
	143	if (acl != ACL_NOT_CACHED)
	144	return acl;
	145
	146	switch (type) {
	147	case ACL_TYPE_ACCESS:
	148	name_index = EXT2_XATTR_INDEX_POSIX_ACL_ACCESS;
	149	break;
	150	case ACL_TYPE_DEFAULT:
	151	name_index = EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT;
	152	break;
	153	default:
	154	BUG();
1da177e4 LT	155	}
	156	retval = ext2_xattr_get(inode, name_index, "", NULL, 0);
	157	if (retval > 0) {
	158	value = kmalloc(retval, GFP_KERNEL);
	159	if (!value)
	160	return ERR_PTR(-ENOMEM);
	161	retval = ext2_xattr_get(inode, name_index, "", value, retval);
	162	}
	163	if (retval > 0)
	164	acl = ext2_acl_from_disk(value, retval);
	165	else if (retval == -ENODATA \|\| retval == -ENOSYS)
	166	acl = NULL;
	167	else
	168	acl = ERR_PTR(retval);
f99d49ad	169	kfree(value);
1da177e4	170
073aaa1b AV	171	if (!IS_ERR(acl))
073aaa1b AV	172	set_cached_acl(inode, type, acl);
1da177e4	173
1da177e4 LT	174	return acl;
	175	}
	176
	177	/*
1b1dcc1b	178	* inode->i_mutex: down
1da177e4 LT	179	*/
	180	static int
	181	ext2_set_acl(struct inode inode, int type, struct posix_acl acl)
	182	{
1da177e4 LT	183	int name_index;
1da177e4 LT	184	void *value = NULL;
dfa08592	185	size_t size = 0;
1da177e4 LT	186	int error;
	187
	188	if (S_ISLNK(inode->i_mode))
	189	return -EOPNOTSUPP;
	190	if (!test_opt(inode->i_sb, POSIX_ACL))
	191	return 0;
	192
	193	switch(type) {
	194	case ACL_TYPE_ACCESS:
	195	name_index = EXT2_XATTR_INDEX_POSIX_ACL_ACCESS;
	196	if (acl) {
	197	mode_t mode = inode->i_mode;
	198	error = posix_acl_equiv_mode(acl, &mode);
	199	if (error < 0)
	200	return error;
	201	else {
	202	inode->i_mode = mode;
	203	mark_inode_dirty(inode);
	204	if (error == 0)
	205	acl = NULL;
	206	}
	207	}
	208	break;
	209
	210	case ACL_TYPE_DEFAULT:
	211	name_index = EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT;
	212	if (!S_ISDIR(inode->i_mode))
	213	return acl ? -EACCES : 0;
	214	break;
	215
	216	default:
	217	return -EINVAL;
	218	}
	219	if (acl) {
	220	value = ext2_acl_to_disk(acl, &size);
	221	if (IS_ERR(value))
	222	return (int)PTR_ERR(value);
	223	}
	224
	225	error = ext2_xattr_set(inode, name_index, "", value, size, 0);
	226
f99d49ad	227	kfree(value);
073aaa1b AV	228	if (!error)
073aaa1b AV	229	set_cached_acl(inode, type, acl);
1da177e4 LT	230	return error;
	231	}
	232
	233	static int
	234	ext2_check_acl(struct inode *inode, int mask)
	235	{
	236	struct posix_acl *acl = ext2_get_acl(inode, ACL_TYPE_ACCESS);
	237
e493073d	238	if (IS_ERR(acl))
e493073d	239	return PTR_ERR(acl);
1da177e4 LT	240	if (acl) {
	241	int error = posix_acl_permission(inode, acl, mask);
	242	posix_acl_release(acl);
	243	return error;
	244	}
	245
	246	return -EAGAIN;
	247	}
	248
	249	int
e6305c43	250	ext2_permission(struct inode *inode, int mask)
1da177e4 LT	251	{
	252	return generic_permission(inode, mask, ext2_check_acl);
	253	}
	254
	255	/*
	256	* Initialize the ACLs of a new inode. Called from ext2_new_inode.
	257	*
1b1dcc1b JS	258	* dir->i_mutex: down
1b1dcc1b JS	259	* inode->i_mutex: up (access to inode is still exclusive)
1da177e4 LT	260	*/
	261	int
	262	ext2_init_acl(struct inode inode, struct inode dir)
	263	{
	264	struct posix_acl *acl = NULL;
	265	int error = 0;
	266
	267	if (!S_ISLNK(inode->i_mode)) {
	268	if (test_opt(dir->i_sb, POSIX_ACL)) {
	269	acl = ext2_get_acl(dir, ACL_TYPE_DEFAULT);
	270	if (IS_ERR(acl))
	271	return PTR_ERR(acl);
	272	}
	273	if (!acl)
ce3b0f8d	274	inode->i_mode &= ~current_umask();
1da177e4 LT	275	}
	276	if (test_opt(inode->i_sb, POSIX_ACL) && acl) {
	277	struct posix_acl *clone;
	278	mode_t mode;
	279
	280	if (S_ISDIR(inode->i_mode)) {
	281	error = ext2_set_acl(inode, ACL_TYPE_DEFAULT, acl);
	282	if (error)
	283	goto cleanup;
	284	}
	285	clone = posix_acl_clone(acl, GFP_KERNEL);
	286	error = -ENOMEM;
	287	if (!clone)
	288	goto cleanup;
	289	mode = inode->i_mode;
	290	error = posix_acl_create_masq(clone, &mode);
	291	if (error >= 0) {
	292	inode->i_mode = mode;
	293	if (error > 0) {
	294	/* This is an extended ACL */
	295	error = ext2_set_acl(inode,
	296	ACL_TYPE_ACCESS, clone);
	297	}
	298	}
	299	posix_acl_release(clone);
	300	}
	301	cleanup:
	302	posix_acl_release(acl);
	303	return error;
	304	}
	305
	306	/*
	307	* Does chmod for an inode that may have an Access Control List. The
	308	* inode->i_mode field must be updated to the desired value by the caller
	309	* before calling this function.
	310	* Returns 0 on success, or a negative error number.
	311	*
	312	* We change the ACL rather than storing some ACL entries in the file
	313	* mode permission bits (which would be more efficient), because that
	314	* would break once additional permissions (like ACL_APPEND, ACL_DELETE
	315	* for directories) are added. There are no more bits available in the
	316	* file mode.
	317	*
1b1dcc1b	318	* inode->i_mutex: down
1da177e4 LT	319	*/
	320	int
	321	ext2_acl_chmod(struct inode *inode)
	322	{
	323	struct posix_acl acl, clone;
	324	int error;
	325
	326	if (!test_opt(inode->i_sb, POSIX_ACL))
	327	return 0;
	328	if (S_ISLNK(inode->i_mode))
	329	return -EOPNOTSUPP;
	330	acl = ext2_get_acl(inode, ACL_TYPE_ACCESS);
	331	if (IS_ERR(acl) \|\| !acl)
	332	return PTR_ERR(acl);
	333	clone = posix_acl_clone(acl, GFP_KERNEL);
	334	posix_acl_release(acl);
	335	if (!clone)
	336	return -ENOMEM;
	337	error = posix_acl_chmod_masq(clone, inode->i_mode);
	338	if (!error)
	339	error = ext2_set_acl(inode, ACL_TYPE_ACCESS, clone);
	340	posix_acl_release(clone);
	341	return error;
	342	}
	343
	344	/*
	345	* Extended attribut handlers
	346	*/
	347	static size_t
	348	ext2_xattr_list_acl_access(struct inode inode, char list, size_t list_size,
	349	const char *name, size_t name_len)
	350	{
9a59f452	351	const size_t size = sizeof(POSIX_ACL_XATTR_ACCESS);
1da177e4 LT	352
	353	if (!test_opt(inode->i_sb, POSIX_ACL))
	354	return 0;
	355	if (list && size <= list_size)
9a59f452	356	memcpy(list, POSIX_ACL_XATTR_ACCESS, size);
1da177e4 LT	357	return size;
	358	}
	359
	360	static size_t
	361	ext2_xattr_list_acl_default(struct inode inode, char list, size_t list_size,
	362	const char *name, size_t name_len)
	363	{
9a59f452	364	const size_t size = sizeof(POSIX_ACL_XATTR_DEFAULT);
1da177e4 LT	365
	366	if (!test_opt(inode->i_sb, POSIX_ACL))
	367	return 0;
	368	if (list && size <= list_size)
9a59f452	369	memcpy(list, POSIX_ACL_XATTR_DEFAULT, size);
1da177e4 LT	370	return size;
	371	}
	372
	373	static int
	374	ext2_xattr_get_acl(struct inode inode, int type, void buffer, size_t size)
	375	{
	376	struct posix_acl *acl;
	377	int error;
	378
	379	if (!test_opt(inode->i_sb, POSIX_ACL))
	380	return -EOPNOTSUPP;
	381
	382	acl = ext2_get_acl(inode, type);
	383	if (IS_ERR(acl))
	384	return PTR_ERR(acl);
	385	if (acl == NULL)
	386	return -ENODATA;
	387	error = posix_acl_to_xattr(acl, buffer, size);
	388	posix_acl_release(acl);
	389
	390	return error;
	391	}
	392
	393	static int
	394	ext2_xattr_get_acl_access(struct inode inode, const char name,
	395	void *buffer, size_t size)
	396	{
	397	if (strcmp(name, "") != 0)
	398	return -EINVAL;
	399	return ext2_xattr_get_acl(inode, ACL_TYPE_ACCESS, buffer, size);
	400	}
	401
	402	static int
	403	ext2_xattr_get_acl_default(struct inode inode, const char name,
	404	void *buffer, size_t size)
	405	{
	406	if (strcmp(name, "") != 0)
	407	return -EINVAL;
	408	return ext2_xattr_get_acl(inode, ACL_TYPE_DEFAULT, buffer, size);
	409	}
	410
	411	static int
	412	ext2_xattr_set_acl(struct inode inode, int type, const void value,
	413	size_t size)
	414	{
	415	struct posix_acl *acl;
	416	int error;
	417
	418	if (!test_opt(inode->i_sb, POSIX_ACL))
	419	return -EOPNOTSUPP;
3bd858ab	420	if (!is_owner_or_cap(inode))
1da177e4 LT	421	return -EPERM;
	422
	423	if (value) {
	424	acl = posix_acl_from_xattr(value, size);
	425	if (IS_ERR(acl))
	426	return PTR_ERR(acl);
	427	else if (acl) {
	428	error = posix_acl_valid(acl);
	429	if (error)
	430	goto release_and_out;
	431	}
	432	} else
	433	acl = NULL;
	434
	435	error = ext2_set_acl(inode, type, acl);
	436
	437	release_and_out:
	438	posix_acl_release(acl);
	439	return error;
	440	}
	441
	442	static int
	443	ext2_xattr_set_acl_access(struct inode inode, const char name,
	444	const void *value, size_t size, int flags)
	445	{
	446	if (strcmp(name, "") != 0)
	447	return -EINVAL;
	448	return ext2_xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size);
	449	}
	450
	451	static int
	452	ext2_xattr_set_acl_default(struct inode inode, const char name,
	453	const void *value, size_t size, int flags)
	454	{
	455	if (strcmp(name, "") != 0)
	456	return -EINVAL;
	457	return ext2_xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size);
	458	}
	459
	460	struct xattr_handler ext2_xattr_acl_access_handler = {
9a59f452	461	.prefix = POSIX_ACL_XATTR_ACCESS,
1da177e4 LT	462	.list = ext2_xattr_list_acl_access,
	463	.get = ext2_xattr_get_acl_access,
	464	.set = ext2_xattr_set_acl_access,
	465	};
	466
	467	struct xattr_handler ext2_xattr_acl_default_handler = {
9a59f452	468	.prefix = POSIX_ACL_XATTR_DEFAULT,
1da177e4 LT	469	.list = ext2_xattr_list_acl_default,
	470	.get = ext2_xattr_get_acl_default,
	471	.set = ext2_xattr_set_acl_default,
	472	};