[mirror_ubuntu-bionic-kernel.git] / fs / ext3 / acl.c

/*
 * linux/fs/ext3/acl.c
 *
 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
 */

#include "ext3.h"
#include "xattr.h"
#include "acl.h"

/*
 * Convert from filesystem to in-memory representation.
 */
static struct posix_acl *
ext3_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(ext3_acl_header))
		 return ERR_PTR(-EINVAL);
	if (((ext3_acl_header *)value)->a_version !=
	    cpu_to_le32(EXT3_ACL_VERSION))
		return ERR_PTR(-EINVAL);
	value = (char *)value + sizeof(ext3_acl_header);
	count = ext3_acl_count(size);
	if (count < 0)
		return ERR_PTR(-EINVAL);
	if (count == 0)
		return NULL;
	acl = posix_acl_alloc(count, GFP_NOFS);
	if (!acl)
		return ERR_PTR(-ENOMEM);
	for (n=0; n < count; n++) {
		ext3_acl_entry *entry =
			(ext3_acl_entry *)value;
		if ((char *)value + sizeof(ext3_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(ext3_acl_entry_short);
				break;

			case ACL_USER:
				value = (char *)value + sizeof(ext3_acl_entry);
				if ((char *)value > end)
					goto fail;
				acl->a_entries[n].e_uid =
					make_kuid(&init_user_ns,
						  le32_to_cpu(entry->e_id));
				break;
			case ACL_GROUP:
				value = (char *)value + sizeof(ext3_acl_entry);
				if ((char *)value > end)
					goto fail;
				acl->a_entries[n].e_gid =
					make_kgid(&init_user_ns,
						  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 *
ext3_acl_to_disk(const struct posix_acl *acl, size_t *size)
{
	ext3_acl_header *ext_acl;
	char *e;
	size_t n;

	*size = ext3_acl_size(acl->a_count);
	ext_acl = kmalloc(sizeof(ext3_acl_header) + acl->a_count *
			sizeof(ext3_acl_entry), GFP_NOFS);
	if (!ext_acl)
		return ERR_PTR(-ENOMEM);
	ext_acl->a_version = cpu_to_le32(EXT3_ACL_VERSION);
	e = (char *)ext_acl + sizeof(ext3_acl_header);
	for (n=0; n < acl->a_count; n++) {
		const struct posix_acl_entry *acl_e = &acl->a_entries[n];
		ext3_acl_entry *entry = (ext3_acl_entry *)e;
		entry->e_tag  = cpu_to_le16(acl_e->e_tag);
		entry->e_perm = cpu_to_le16(acl_e->e_perm);
		switch(acl_e->e_tag) {
			case ACL_USER:
				entry->e_id = cpu_to_le32(
					from_kuid(&init_user_ns, acl_e->e_uid));
				e += sizeof(ext3_acl_entry);
				break;
			case ACL_GROUP:
				entry->e_id = cpu_to_le32(
					from_kgid(&init_user_ns, acl_e->e_gid));
				e += sizeof(ext3_acl_entry);
				break;

			case ACL_USER_OBJ:
			case ACL_GROUP_OBJ:
			case ACL_MASK:
			case ACL_OTHER:
				e += sizeof(ext3_acl_entry_short);
				break;

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

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

/*
 * Inode operation get_posix_acl().
 *
 * inode->i_mutex: don't care
 */
struct posix_acl *
ext3_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 = EXT3_XATTR_INDEX_POSIX_ACL_ACCESS;
		break;
	case ACL_TYPE_DEFAULT:
		name_index = EXT3_XATTR_INDEX_POSIX_ACL_DEFAULT;
		break;
	default:
		BUG();
	}

	retval = ext3_xattr_get(inode, name_index, "", NULL, 0);
	if (retval > 0) {
		value = kmalloc(retval, GFP_NOFS);
		if (!value)
			return ERR_PTR(-ENOMEM);
		retval = ext3_xattr_get(inode, name_index, "", value, retval);
	}
	if (retval > 0)
		acl = ext3_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;
}

/*
 * Set the access or default ACL of an inode.
 *
 * inode->i_mutex: down unless called from ext3_new_inode
 */
static int
ext3_set_acl(handle_t *handle, 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;

	switch(type) {
		case ACL_TYPE_ACCESS:
			name_index = EXT3_XATTR_INDEX_POSIX_ACL_ACCESS;
			if (acl) {
				error = posix_acl_equiv_mode(acl, &inode->i_mode);
				if (error < 0)
					return error;
				else {
					inode->i_ctime = CURRENT_TIME_SEC;
					ext3_mark_inode_dirty(handle, inode);
					if (error == 0)
						acl = NULL;
				}
			}
			break;

		case ACL_TYPE_DEFAULT:
			name_index = EXT3_XATTR_INDEX_POSIX_ACL_DEFAULT;
			if (!S_ISDIR(inode->i_mode))
				return acl ? -EACCES : 0;
			break;

		default:
			return -EINVAL;
	}
	if (acl) {
		value = ext3_acl_to_disk(acl, &size);
		if (IS_ERR(value))
			return (int)PTR_ERR(value);
	}

	error = ext3_xattr_set_handle(handle, inode, name_index, "",
				      value, size, 0);

	kfree(value);

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

	return error;
}

/*
 * Initialize the ACLs of a new inode. Called from ext3_new_inode.
 *
 * dir->i_mutex: down
 * inode->i_mutex: up (access to inode is still exclusive)
 */
int
ext3_init_acl(handle_t *handle, 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 = ext3_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) {
		if (S_ISDIR(inode->i_mode)) {
			error = ext3_set_acl(handle, inode,
					     ACL_TYPE_DEFAULT, acl);
			if (error)
				goto cleanup;
		}
		error = posix_acl_create(&acl, GFP_NOFS, &inode->i_mode);
		if (error < 0)
			return error;

		if (error > 0) {
			/* This is an extended ACL */
			error = ext3_set_acl(handle, inode, ACL_TYPE_ACCESS, acl);
		}
	}
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
ext3_acl_chmod(struct inode *inode)
{
	struct posix_acl *acl;
	handle_t *handle;
	int retries = 0;
        int error;

	if (S_ISLNK(inode->i_mode))
		return -EOPNOTSUPP;
	if (!test_opt(inode->i_sb, POSIX_ACL))
		return 0;
	acl = ext3_get_acl(inode, ACL_TYPE_ACCESS);
	if (IS_ERR(acl) || !acl)
		return PTR_ERR(acl);
	error = posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode);
	if (error)
		return error;
retry:
	handle = ext3_journal_start(inode,
			EXT3_DATA_TRANS_BLOCKS(inode->i_sb));
	if (IS_ERR(handle)) {
		error = PTR_ERR(handle);
		ext3_std_error(inode->i_sb, error);
		goto out;
	}
	error = ext3_set_acl(handle, inode, ACL_TYPE_ACCESS, acl);
	ext3_journal_stop(handle);
	if (error == -ENOSPC &&
	    ext3_should_retry_alloc(inode->i_sb, &retries))
		goto retry;
out:
	posix_acl_release(acl);
	return error;
}

/*
 * Extended attribute handlers
 */
static size_t
ext3_xattr_list_acl_access(struct dentry *dentry, char *list, size_t list_len,
			   const char *name, size_t name_len, int type)
{
	const size_t size = sizeof(POSIX_ACL_XATTR_ACCESS);

	if (!test_opt(dentry->d_sb, POSIX_ACL))
		return 0;
	if (list && size <= list_len)
		memcpy(list, POSIX_ACL_XATTR_ACCESS, size);
	return size;
}

static size_t
ext3_xattr_list_acl_default(struct dentry *dentry, char *list, size_t list_len,
			    const char *name, size_t name_len, int type)
{
	const size_t size = sizeof(POSIX_ACL_XATTR_DEFAULT);

	if (!test_opt(dentry->d_sb, POSIX_ACL))
		return 0;
	if (list && size <= list_len)
		memcpy(list, POSIX_ACL_XATTR_DEFAULT, size);
	return size;
}

static int
ext3_xattr_get_acl(struct dentry *dentry, const char *name, void *buffer,
		   size_t size, int type)
{
	struct posix_acl *acl;
	int error;

	if (strcmp(name, "") != 0)
		return -EINVAL;
	if (!test_opt(dentry->d_sb, POSIX_ACL))
		return -EOPNOTSUPP;

	acl = ext3_get_acl(dentry->d_inode, type);
	if (IS_ERR(acl))
		return PTR_ERR(acl);
	if (acl == NULL)
		return -ENODATA;
	error = posix_acl_to_xattr(&init_user_ns, acl, buffer, size);
	posix_acl_release(acl);

	return error;
}

static int
ext3_xattr_set_acl(struct dentry *dentry, const char *name, const void *value,
		   size_t size, int flags, int type)
{
	struct inode *inode = dentry->d_inode;
	handle_t *handle;
	struct posix_acl *acl;
	int error, retries = 0;

	if (strcmp(name, "") != 0)
		return -EINVAL;
	if (!test_opt(inode->i_sb, POSIX_ACL))
		return -EOPNOTSUPP;
	if (!inode_owner_or_capable(inode))
		return -EPERM;

	if (value) {
		acl = posix_acl_from_xattr(&init_user_ns, 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;

retry:
	handle = ext3_journal_start(inode, EXT3_DATA_TRANS_BLOCKS(inode->i_sb));
	if (IS_ERR(handle))
		return PTR_ERR(handle);
	error = ext3_set_acl(handle, inode, type, acl);
	ext3_journal_stop(handle);
	if (error == -ENOSPC && ext3_should_retry_alloc(inode->i_sb, &retries))
		goto retry;

release_and_out:
	posix_acl_release(acl);
	return error;
}

const struct xattr_handler ext3_xattr_acl_access_handler = {
	.prefix	= POSIX_ACL_XATTR_ACCESS,
	.flags	= ACL_TYPE_ACCESS,
	.list	= ext3_xattr_list_acl_access,
	.get	= ext3_xattr_get_acl,
	.set	= ext3_xattr_set_acl,
};

const struct xattr_handler ext3_xattr_acl_default_handler = {
	.prefix	= POSIX_ACL_XATTR_DEFAULT,
	.flags	= ACL_TYPE_DEFAULT,
	.list	= ext3_xattr_list_acl_default,
	.get	= ext3_xattr_get_acl,
	.set	= ext3_xattr_set_acl,
};
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/fs/ext3/acl.c
	3	*
	4	* Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
	5	*/
	6
4613ad18	7	#include "ext3.h"
1da177e4 LT	8	#include "xattr.h"
	9	#include "acl.h"
	10
	11	/*
	12	* Convert from filesystem to in-memory representation.
	13	*/
	14	static struct posix_acl *
	15	ext3_acl_from_disk(const void *value, size_t size)
	16	{
	17	const char end = (char )value + size;
	18	int n, count;
	19	struct posix_acl *acl;
	20
	21	if (!value)
	22	return NULL;
	23	if (size < sizeof(ext3_acl_header))
	24	return ERR_PTR(-EINVAL);
	25	if (((ext3_acl_header *)value)->a_version !=
	26	cpu_to_le32(EXT3_ACL_VERSION))
	27	return ERR_PTR(-EINVAL);
	28	value = (char *)value + sizeof(ext3_acl_header);
	29	count = ext3_acl_count(size);
	30	if (count < 0)
	31	return ERR_PTR(-EINVAL);
	32	if (count == 0)
	33	return NULL;
c587f0c0	34	acl = posix_acl_alloc(count, GFP_NOFS);
1da177e4 LT	35	if (!acl)
	36	return ERR_PTR(-ENOMEM);
	37	for (n=0; n < count; n++) {
	38	ext3_acl_entry *entry =
	39	(ext3_acl_entry *)value;
	40	if ((char *)value + sizeof(ext3_acl_entry_short) > end)
	41	goto fail;
	42	acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag);
	43	acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
	44	switch(acl->a_entries[n].e_tag) {
	45	case ACL_USER_OBJ:
	46	case ACL_GROUP_OBJ:
	47	case ACL_MASK:
	48	case ACL_OTHER:
	49	value = (char *)value +
	50	sizeof(ext3_acl_entry_short);
1da177e4 LT	51	break;
	52
	53	case ACL_USER:
af84df93 EB	54	value = (char *)value + sizeof(ext3_acl_entry);
	55	if ((char *)value > end)
	56	goto fail;
	57	acl->a_entries[n].e_uid =
	58	make_kuid(&init_user_ns,
	59	le32_to_cpu(entry->e_id));
	60	break;
1da177e4 LT	61	case ACL_GROUP:
	62	value = (char *)value + sizeof(ext3_acl_entry);
	63	if ((char *)value > end)
	64	goto fail;
af84df93 EB	65	acl->a_entries[n].e_gid =
	66	make_kgid(&init_user_ns,
	67	le32_to_cpu(entry->e_id));
1da177e4 LT	68	break;
	69
	70	default:
	71	goto fail;
	72	}
	73	}
	74	if (value != end)
	75	goto fail;
	76	return acl;
	77
	78	fail:
	79	posix_acl_release(acl);
	80	return ERR_PTR(-EINVAL);
	81	}
	82
	83	/*
	84	* Convert from in-memory to filesystem representation.
	85	*/
	86	static void *
	87	ext3_acl_to_disk(const struct posix_acl acl, size_t size)
	88	{
	89	ext3_acl_header *ext_acl;
	90	char *e;
	91	size_t n;
	92
	93	*size = ext3_acl_size(acl->a_count);
f52720ca	94	ext_acl = kmalloc(sizeof(ext3_acl_header) + acl->a_count *
c587f0c0	95	sizeof(ext3_acl_entry), GFP_NOFS);
1da177e4 LT	96	if (!ext_acl)
	97	return ERR_PTR(-ENOMEM);
	98	ext_acl->a_version = cpu_to_le32(EXT3_ACL_VERSION);
	99	e = (char *)ext_acl + sizeof(ext3_acl_header);
	100	for (n=0; n < acl->a_count; n++) {
af84df93	101	const struct posix_acl_entry *acl_e = &acl->a_entries[n];
1da177e4	102	ext3_acl_entry entry = (ext3_acl_entry )e;
af84df93 EB	103	entry->e_tag = cpu_to_le16(acl_e->e_tag);
	104	entry->e_perm = cpu_to_le16(acl_e->e_perm);
	105	switch(acl_e->e_tag) {
1da177e4	106	case ACL_USER:
af84df93 EB	107	entry->e_id = cpu_to_le32(
	108	from_kuid(&init_user_ns, acl_e->e_uid));
	109	e += sizeof(ext3_acl_entry);
	110	break;
1da177e4	111	case ACL_GROUP:
af84df93 EB	112	entry->e_id = cpu_to_le32(
af84df93 EB	113	from_kgid(&init_user_ns, acl_e->e_gid));
1da177e4 LT	114	e += sizeof(ext3_acl_entry);
	115	break;
	116
	117	case ACL_USER_OBJ:
	118	case ACL_GROUP_OBJ:
	119	case ACL_MASK:
	120	case ACL_OTHER:
	121	e += sizeof(ext3_acl_entry_short);
	122	break;
	123
	124	default:
	125	goto fail;
	126	}
	127	}
	128	return (char *)ext_acl;
	129
	130	fail:
	131	kfree(ext_acl);
	132	return ERR_PTR(-EINVAL);
	133	}
	134
1da177e4 LT	135	/*
	136	* Inode operation get_posix_acl().
	137	*
1b1dcc1b	138	* inode->i_mutex: don't care
1da177e4	139	*/
4e34e719	140	struct posix_acl *
1da177e4 LT	141	ext3_get_acl(struct inode *inode, int type)
1da177e4 LT	142	{
1da177e4 LT	143	int name_index;
	144	char *value = NULL;
	145	struct posix_acl *acl;
	146	int retval;
	147
	148	if (!test_opt(inode->i_sb, POSIX_ACL))
	149	return NULL;
	150
073aaa1b AV	151	acl = get_cached_acl(inode, type);
	152	if (acl != ACL_NOT_CACHED)
	153	return acl;
	154
	155	switch (type) {
	156	case ACL_TYPE_ACCESS:
	157	name_index = EXT3_XATTR_INDEX_POSIX_ACL_ACCESS;
	158	break;
	159	case ACL_TYPE_DEFAULT:
	160	name_index = EXT3_XATTR_INDEX_POSIX_ACL_DEFAULT;
	161	break;
	162	default:
	163	BUG();
1da177e4	164	}
073aaa1b	165
1da177e4 LT	166	retval = ext3_xattr_get(inode, name_index, "", NULL, 0);
1da177e4 LT	167	if (retval > 0) {
c587f0c0	168	value = kmalloc(retval, GFP_NOFS);
1da177e4 LT	169	if (!value)
	170	return ERR_PTR(-ENOMEM);
	171	retval = ext3_xattr_get(inode, name_index, "", value, retval);
	172	}
	173	if (retval > 0)
	174	acl = ext3_acl_from_disk(value, retval);
	175	else if (retval == -ENODATA \|\| retval == -ENOSYS)
	176	acl = NULL;
	177	else
	178	acl = ERR_PTR(retval);
	179	kfree(value);
	180
073aaa1b AV	181	if (!IS_ERR(acl))
073aaa1b AV	182	set_cached_acl(inode, type, acl);
1da177e4	183
1da177e4 LT	184	return acl;
	185	}
	186
	187	/*
	188	* Set the access or default ACL of an inode.
	189	*
1b1dcc1b	190	* inode->i_mutex: down unless called from ext3_new_inode
1da177e4 LT	191	*/
	192	static int
	193	ext3_set_acl(handle_t handle, struct inode inode, int type,
	194	struct posix_acl *acl)
	195	{
1da177e4 LT	196	int name_index;
1da177e4 LT	197	void *value = NULL;
dfa08592	198	size_t size = 0;
1da177e4 LT	199	int error;
	200
	201	if (S_ISLNK(inode->i_mode))
	202	return -EOPNOTSUPP;
	203
	204	switch(type) {
	205	case ACL_TYPE_ACCESS:
	206	name_index = EXT3_XATTR_INDEX_POSIX_ACL_ACCESS;
	207	if (acl) {
d6952123	208	error = posix_acl_equiv_mode(acl, &inode->i_mode);
1da177e4 LT	209	if (error < 0)
	210	return error;
	211	else {
30e2bab2	212	inode->i_ctime = CURRENT_TIME_SEC;
1da177e4 LT	213	ext3_mark_inode_dirty(handle, inode);
	214	if (error == 0)
	215	acl = NULL;
	216	}
	217	}
	218	break;
	219
	220	case ACL_TYPE_DEFAULT:
	221	name_index = EXT3_XATTR_INDEX_POSIX_ACL_DEFAULT;
	222	if (!S_ISDIR(inode->i_mode))
	223	return acl ? -EACCES : 0;
	224	break;
	225
	226	default:
	227	return -EINVAL;
	228	}
e9ad5620	229	if (acl) {
1da177e4 LT	230	value = ext3_acl_to_disk(acl, &size);
	231	if (IS_ERR(value))
	232	return (int)PTR_ERR(value);
	233	}
	234
	235	error = ext3_xattr_set_handle(handle, inode, name_index, "",
	236	value, size, 0);
	237
	238	kfree(value);
1da177e4	239
073aaa1b AV	240	if (!error)
	241	set_cached_acl(inode, type, acl);
	242
1da177e4 LT	243	return error;
	244	}
	245
1da177e4 LT	246	/*
	247	* Initialize the ACLs of a new inode. Called from ext3_new_inode.
	248	*
1b1dcc1b JS	249	* dir->i_mutex: down
1b1dcc1b JS	250	* inode->i_mutex: up (access to inode is still exclusive)
1da177e4 LT	251	*/
	252	int
	253	ext3_init_acl(handle_t handle, struct inode inode, struct inode *dir)
	254	{
	255	struct posix_acl *acl = NULL;
	256	int error = 0;
	257
	258	if (!S_ISLNK(inode->i_mode)) {
	259	if (test_opt(dir->i_sb, POSIX_ACL)) {
	260	acl = ext3_get_acl(dir, ACL_TYPE_DEFAULT);
	261	if (IS_ERR(acl))
	262	return PTR_ERR(acl);
	263	}
	264	if (!acl)
ce3b0f8d	265	inode->i_mode &= ~current_umask();
1da177e4 LT	266	}
1da177e4 LT	267	if (test_opt(inode->i_sb, POSIX_ACL) && acl) {
1da177e4 LT	268	if (S_ISDIR(inode->i_mode)) {
	269	error = ext3_set_acl(handle, inode,
	270	ACL_TYPE_DEFAULT, acl);
	271	if (error)
	272	goto cleanup;
	273	}
d3fb6120	274	error = posix_acl_create(&acl, GFP_NOFS, &inode->i_mode);
826cae2f AV	275	if (error < 0)
	276	return error;
	277
826cae2f AV	278	if (error > 0) {
	279	/* This is an extended ACL */
	280	error = ext3_set_acl(handle, inode, ACL_TYPE_ACCESS, acl);
1da177e4	281	}
1da177e4 LT	282	}
	283	cleanup:
	284	posix_acl_release(acl);
	285	return error;
	286	}
	287
	288	/*
	289	* Does chmod for an inode that may have an Access Control List. The
	290	* inode->i_mode field must be updated to the desired value by the caller
	291	* before calling this function.
	292	* Returns 0 on success, or a negative error number.
	293	*
	294	* We change the ACL rather than storing some ACL entries in the file
	295	* mode permission bits (which would be more efficient), because that
	296	* would break once additional permissions (like ACL_APPEND, ACL_DELETE
	297	* for directories) are added. There are no more bits available in the
	298	* file mode.
	299	*
1b1dcc1b	300	* inode->i_mutex: down
1da177e4 LT	301	*/
	302	int
	303	ext3_acl_chmod(struct inode *inode)
	304	{
bc26ab5f AV	305	struct posix_acl *acl;
	306	handle_t *handle;
	307	int retries = 0;
1da177e4 LT	308	int error;
	309
	310	if (S_ISLNK(inode->i_mode))
	311	return -EOPNOTSUPP;
	312	if (!test_opt(inode->i_sb, POSIX_ACL))
	313	return 0;
	314	acl = ext3_get_acl(inode, ACL_TYPE_ACCESS);
	315	if (IS_ERR(acl) \|\| !acl)
	316	return PTR_ERR(acl);
bc26ab5f AV	317	error = posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode);
	318	if (error)
	319	return error;
	320	retry:
	321	handle = ext3_journal_start(inode,
	322	EXT3_DATA_TRANS_BLOCKS(inode->i_sb));
	323	if (IS_ERR(handle)) {
	324	error = PTR_ERR(handle);
	325	ext3_std_error(inode->i_sb, error);
	326	goto out;
1da177e4	327	}
bc26ab5f AV	328	error = ext3_set_acl(handle, inode, ACL_TYPE_ACCESS, acl);
	329	ext3_journal_stop(handle);
	330	if (error == -ENOSPC &&
	331	ext3_should_retry_alloc(inode->i_sb, &retries))
	332	goto retry;
1da177e4	333	out:
bc26ab5f	334	posix_acl_release(acl);
1da177e4 LT	335	return error;
	336	}
	337
	338	/*
	339	* Extended attribute handlers
	340	*/
	341	static size_t
431547b3 CH	342	ext3_xattr_list_acl_access(struct dentry dentry, char list, size_t list_len,
431547b3 CH	343	const char *name, size_t name_len, int type)
1da177e4	344	{
9a59f452	345	const size_t size = sizeof(POSIX_ACL_XATTR_ACCESS);
1da177e4	346
431547b3	347	if (!test_opt(dentry->d_sb, POSIX_ACL))
1da177e4 LT	348	return 0;
1da177e4 LT	349	if (list && size <= list_len)
9a59f452	350	memcpy(list, POSIX_ACL_XATTR_ACCESS, size);
1da177e4 LT	351	return size;
	352	}
	353
	354	static size_t
431547b3 CH	355	ext3_xattr_list_acl_default(struct dentry dentry, char list, size_t list_len,
431547b3 CH	356	const char *name, size_t name_len, int type)
1da177e4	357	{
9a59f452	358	const size_t size = sizeof(POSIX_ACL_XATTR_DEFAULT);
1da177e4	359
431547b3	360	if (!test_opt(dentry->d_sb, POSIX_ACL))
1da177e4 LT	361	return 0;
1da177e4 LT	362	if (list && size <= list_len)
9a59f452	363	memcpy(list, POSIX_ACL_XATTR_DEFAULT, size);
1da177e4 LT	364	return size;
	365	}
	366
	367	static int
431547b3 CH	368	ext3_xattr_get_acl(struct dentry dentry, const char name, void *buffer,
431547b3 CH	369	size_t size, int type)
1da177e4 LT	370	{
	371	struct posix_acl *acl;
	372	int error;
	373
431547b3 CH	374	if (strcmp(name, "") != 0)
	375	return -EINVAL;
	376	if (!test_opt(dentry->d_sb, POSIX_ACL))
1da177e4 LT	377	return -EOPNOTSUPP;
1da177e4 LT	378
431547b3	379	acl = ext3_get_acl(dentry->d_inode, type);
1da177e4 LT	380	if (IS_ERR(acl))
	381	return PTR_ERR(acl);
	382	if (acl == NULL)
	383	return -ENODATA;
5f3a4a28	384	error = posix_acl_to_xattr(&init_user_ns, acl, buffer, size);
1da177e4 LT	385	posix_acl_release(acl);
	386
	387	return error;
	388	}
	389
	390	static int
431547b3 CH	391	ext3_xattr_set_acl(struct dentry dentry, const char name, const void *value,
431547b3 CH	392	size_t size, int flags, int type)
1da177e4	393	{
431547b3	394	struct inode *inode = dentry->d_inode;
1da177e4 LT	395	handle_t *handle;
	396	struct posix_acl *acl;
	397	int error, retries = 0;
	398
431547b3 CH	399	if (strcmp(name, "") != 0)
431547b3 CH	400	return -EINVAL;
1da177e4 LT	401	if (!test_opt(inode->i_sb, POSIX_ACL))
1da177e4 LT	402	return -EOPNOTSUPP;
2e149670	403	if (!inode_owner_or_capable(inode))
1da177e4 LT	404	return -EPERM;
	405
	406	if (value) {
5f3a4a28	407	acl = posix_acl_from_xattr(&init_user_ns, value, size);
1da177e4 LT	408	if (IS_ERR(acl))
	409	return PTR_ERR(acl);
	410	else if (acl) {
	411	error = posix_acl_valid(acl);
	412	if (error)
	413	goto release_and_out;
	414	}
	415	} else
	416	acl = NULL;
	417
	418	retry:
1f54587b	419	handle = ext3_journal_start(inode, EXT3_DATA_TRANS_BLOCKS(inode->i_sb));
1da177e4 LT	420	if (IS_ERR(handle))
	421	return PTR_ERR(handle);
	422	error = ext3_set_acl(handle, inode, type, acl);
	423	ext3_journal_stop(handle);
	424	if (error == -ENOSPC && ext3_should_retry_alloc(inode->i_sb, &retries))
	425	goto retry;
	426
	427	release_and_out:
	428	posix_acl_release(acl);
	429	return error;
	430	}
	431
d1f21049	432	const struct xattr_handler ext3_xattr_acl_access_handler = {
9a59f452	433	.prefix = POSIX_ACL_XATTR_ACCESS,
431547b3	434	.flags = ACL_TYPE_ACCESS,
1da177e4	435	.list = ext3_xattr_list_acl_access,
431547b3 CH	436	.get = ext3_xattr_get_acl,
431547b3 CH	437	.set = ext3_xattr_set_acl,
1da177e4 LT	438	};
1da177e4 LT	439
d1f21049	440	const struct xattr_handler ext3_xattr_acl_default_handler = {
9a59f452	441	.prefix = POSIX_ACL_XATTR_DEFAULT,
431547b3	442	.flags = ACL_TYPE_DEFAULT,
1da177e4	443	.list = ext3_xattr_list_acl_default,
431547b3 CH	444	.get = ext3_xattr_get_acl,
431547b3 CH	445	.set = ext3_xattr_set_acl,
1da177e4	446	};