[mirror_ubuntu-zesty-kernel.git] / fs / ext4 / acl.c

/*
 * linux/fs/ext4/acl.c
 *
 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
 */

#include <linux/init.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/capability.h>
#include <linux/fs.h>
#include "ext4_jbd2.h"
#include "ext4.h"
#include "xattr.h"
#include "acl.h"

/*
 * Convert from filesystem to in-memory representation.
 */
static struct posix_acl *
ext4_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(ext4_acl_header))
		 return ERR_PTR(-EINVAL);
	if (((ext4_acl_header *)value)->a_version !=
	    cpu_to_le32(EXT4_ACL_VERSION))
		return ERR_PTR(-EINVAL);
	value = (char *)value + sizeof(ext4_acl_header);
	count = ext4_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++) {
		ext4_acl_entry *entry =
			(ext4_acl_entry *)value;
		if ((char *)value + sizeof(ext4_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(ext4_acl_entry_short);
			acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
			break;

		case ACL_USER:
		case ACL_GROUP:
			value = (char *)value + sizeof(ext4_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 *
ext4_acl_to_disk(const struct posix_acl *acl, size_t *size)
{
	ext4_acl_header *ext_acl;
	char *e;
	size_t n;

	*size = ext4_acl_size(acl->a_count);
	ext_acl = kmalloc(sizeof(ext4_acl_header) + acl->a_count *
			sizeof(ext4_acl_entry), GFP_NOFS);
	if (!ext_acl)
		return ERR_PTR(-ENOMEM);
	ext_acl->a_version = cpu_to_le32(EXT4_ACL_VERSION);
	e = (char *)ext_acl + sizeof(ext4_acl_header);
	for (n = 0; n < acl->a_count; n++) {
		ext4_acl_entry *entry = (ext4_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(ext4_acl_entry);
			break;

		case ACL_USER_OBJ:
		case ACL_GROUP_OBJ:
		case ACL_MASK:
		case ACL_OTHER:
			e += sizeof(ext4_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
 */
static struct posix_acl *
ext4_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 = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
		break;
	case ACL_TYPE_DEFAULT:
		name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
		break;
	default:
		BUG();
	}
	retval = ext4_xattr_get(inode, name_index, "", NULL, 0);
	if (retval > 0) {
		value = kmalloc(retval, GFP_NOFS);
		if (!value)
			return ERR_PTR(-ENOMEM);
		retval = ext4_xattr_get(inode, name_index, "", value, retval);
	}
	if (retval > 0)
		acl = ext4_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 ext4_new_inode
 */
static int
ext4_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 = EXT4_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;
				inode->i_ctime = ext4_current_time(inode);
				ext4_mark_inode_dirty(handle, inode);
				if (error == 0)
					acl = NULL;
			}
		}
		break;

	case ACL_TYPE_DEFAULT:
		name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
		if (!S_ISDIR(inode->i_mode))
			return acl ? -EACCES : 0;
		break;

	default:
		return -EINVAL;
	}
	if (acl) {
		value = ext4_acl_to_disk(acl, &size);
		if (IS_ERR(value))
			return (int)PTR_ERR(value);
	}

	error = ext4_xattr_set_handle(handle, inode, name_index, "",
				      value, size, 0);

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

	return error;
}

int
ext4_check_acl(struct inode *inode, int mask)
{
	struct posix_acl *acl;

	acl = ext4_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;
}

/*
 * Initialize the ACLs of a new inode. Called from ext4_new_inode.
 *
 * dir->i_mutex: down
 * inode->i_mutex: up (access to inode is still exclusive)
 */
int
ext4_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 = ext4_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 = ext4_set_acl(handle, inode,
					     ACL_TYPE_DEFAULT, acl);
			if (error)
				goto cleanup;
		}
		clone = posix_acl_clone(acl, GFP_NOFS);
		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 = ext4_set_acl(handle, 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
ext4_acl_chmod(struct inode *inode)
{
	struct posix_acl *acl, *clone;
	int error;

	if (S_ISLNK(inode->i_mode))
		return -EOPNOTSUPP;
	if (!test_opt(inode->i_sb, POSIX_ACL))
		return 0;
	acl = ext4_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) {
		handle_t *handle;
		int retries = 0;

	retry:
		handle = ext4_journal_start(inode,
				EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
		if (IS_ERR(handle)) {
			error = PTR_ERR(handle);
			ext4_std_error(inode->i_sb, error);
			goto out;
		}
		error = ext4_set_acl(handle, inode, ACL_TYPE_ACCESS, clone);
		ext4_journal_stop(handle);
		if (error == -ENOSPC &&
		    ext4_should_retry_alloc(inode->i_sb, &retries))
			goto retry;
	}
out:
	posix_acl_release(clone);
	return error;
}

/*
 * Extended attribute handlers
 */
static size_t
ext4_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
ext4_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
ext4_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 = ext4_get_acl(dentry->d_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
ext4_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(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 = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
	if (IS_ERR(handle))
		return PTR_ERR(handle);
	error = ext4_set_acl(handle, inode, type, acl);
	ext4_journal_stop(handle);
	if (error == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
		goto retry;

release_and_out:
	posix_acl_release(acl);
	return error;
}

const struct xattr_handler ext4_xattr_acl_access_handler = {
	.prefix	= POSIX_ACL_XATTR_ACCESS,
	.flags	= ACL_TYPE_ACCESS,
	.list	= ext4_xattr_list_acl_access,
	.get	= ext4_xattr_get_acl,
	.set	= ext4_xattr_set_acl,
};

const struct xattr_handler ext4_xattr_acl_default_handler = {
	.prefix	= POSIX_ACL_XATTR_DEFAULT,
	.flags	= ACL_TYPE_DEFAULT,
	.list	= ext4_xattr_list_acl_default,
	.get	= ext4_xattr_get_acl,
	.set	= ext4_xattr_set_acl,
};
Commit	Line	Data
ac27a0ec	1	/*
617ba13b	2	* linux/fs/ext4/acl.c
ac27a0ec DK	3	*
	4	* Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
	5	*/
	6
	7	#include <linux/init.h>
	8	#include <linux/sched.h>
	9	#include <linux/slab.h>
	10	#include <linux/capability.h>
	11	#include <linux/fs.h>
3dcf5451 CH	12	#include "ext4_jbd2.h"
3dcf5451 CH	13	#include "ext4.h"
ac27a0ec DK	14	#include "xattr.h"
	15	#include "acl.h"
	16
	17	/*
	18	* Convert from filesystem to in-memory representation.
	19	*/
	20	static struct posix_acl *
617ba13b	21	ext4_acl_from_disk(const void *value, size_t size)
ac27a0ec DK	22	{
	23	const char end = (char )value + size;
	24	int n, count;
	25	struct posix_acl *acl;
	26
	27	if (!value)
	28	return NULL;
617ba13b	29	if (size < sizeof(ext4_acl_header))
ac27a0ec	30	return ERR_PTR(-EINVAL);
617ba13b MC	31	if (((ext4_acl_header *)value)->a_version !=
617ba13b MC	32	cpu_to_le32(EXT4_ACL_VERSION))
ac27a0ec	33	return ERR_PTR(-EINVAL);
617ba13b MC	34	value = (char *)value + sizeof(ext4_acl_header);
617ba13b MC	35	count = ext4_acl_count(size);
ac27a0ec DK	36	if (count < 0)
	37	return ERR_PTR(-EINVAL);
	38	if (count == 0)
	39	return NULL;
216553c4	40	acl = posix_acl_alloc(count, GFP_NOFS);
ac27a0ec DK	41	if (!acl)
ac27a0ec DK	42	return ERR_PTR(-ENOMEM);
2b2d6d01	43	for (n = 0; n < count; n++) {
617ba13b MC	44	ext4_acl_entry *entry =
	45	(ext4_acl_entry *)value;
	46	if ((char *)value + sizeof(ext4_acl_entry_short) > end)
ac27a0ec DK	47	goto fail;
	48	acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag);
	49	acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
2b2d6d01 TT	50
	51	switch (acl->a_entries[n].e_tag) {
	52	case ACL_USER_OBJ:
	53	case ACL_GROUP_OBJ:
	54	case ACL_MASK:
	55	case ACL_OTHER:
	56	value = (char *)value +
	57	sizeof(ext4_acl_entry_short);
	58	acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
	59	break;
	60
	61	case ACL_USER:
	62	case ACL_GROUP:
	63	value = (char *)value + sizeof(ext4_acl_entry);
	64	if ((char *)value > end)
ac27a0ec	65	goto fail;
2b2d6d01 TT	66	acl->a_entries[n].e_id =
	67	le32_to_cpu(entry->e_id);
	68	break;
	69
	70	default:
	71	goto fail;
ac27a0ec DK	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 *
617ba13b	87	ext4_acl_to_disk(const struct posix_acl acl, size_t size)
ac27a0ec	88	{
617ba13b	89	ext4_acl_header *ext_acl;
ac27a0ec DK	90	char *e;
	91	size_t n;
	92
617ba13b MC	93	*size = ext4_acl_size(acl->a_count);
617ba13b MC	94	ext_acl = kmalloc(sizeof(ext4_acl_header) + acl->a_count *
216553c4	95	sizeof(ext4_acl_entry), GFP_NOFS);
ac27a0ec DK	96	if (!ext_acl)
ac27a0ec DK	97	return ERR_PTR(-ENOMEM);
617ba13b MC	98	ext_acl->a_version = cpu_to_le32(EXT4_ACL_VERSION);
617ba13b MC	99	e = (char *)ext_acl + sizeof(ext4_acl_header);
2b2d6d01	100	for (n = 0; n < acl->a_count; n++) {
617ba13b	101	ext4_acl_entry entry = (ext4_acl_entry )e;
ac27a0ec DK	102	entry->e_tag = cpu_to_le16(acl->a_entries[n].e_tag);
ac27a0ec DK	103	entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
2b2d6d01 TT	104	switch (acl->a_entries[n].e_tag) {
	105	case ACL_USER:
	106	case ACL_GROUP:
	107	entry->e_id = cpu_to_le32(acl->a_entries[n].e_id);
	108	e += sizeof(ext4_acl_entry);
	109	break;
	110
	111	case ACL_USER_OBJ:
	112	case ACL_GROUP_OBJ:
	113	case ACL_MASK:
	114	case ACL_OTHER:
	115	e += sizeof(ext4_acl_entry_short);
	116	break;
	117
	118	default:
	119	goto fail;
ac27a0ec DK	120	}
	121	}
	122	return (char *)ext_acl;
	123
	124	fail:
	125	kfree(ext_acl);
	126	return ERR_PTR(-EINVAL);
	127	}
	128
ac27a0ec DK	129	/*
	130	* Inode operation get_posix_acl().
	131	*
	132	* inode->i_mutex: don't care
	133	*/
	134	static struct posix_acl *
617ba13b	135	ext4_get_acl(struct inode *inode, int type)
ac27a0ec	136	{
ac27a0ec DK	137	int name_index;
	138	char *value = NULL;
	139	struct posix_acl *acl;
	140	int retval;
	141
	142	if (!test_opt(inode->i_sb, POSIX_ACL))
	143	return NULL;
	144
073aaa1b AV	145	acl = get_cached_acl(inode, type);
	146	if (acl != ACL_NOT_CACHED)
	147	return acl;
	148
2b2d6d01 TT	149	switch (type) {
2b2d6d01 TT	150	case ACL_TYPE_ACCESS:
2b2d6d01 TT	151	name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
2b2d6d01 TT	152	break;
2b2d6d01	153	case ACL_TYPE_DEFAULT:
2b2d6d01 TT	154	name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
2b2d6d01 TT	155	break;
2b2d6d01	156	default:
073aaa1b	157	BUG();
ac27a0ec	158	}
617ba13b	159	retval = ext4_xattr_get(inode, name_index, "", NULL, 0);
ac27a0ec	160	if (retval > 0) {
216553c4	161	value = kmalloc(retval, GFP_NOFS);
ac27a0ec DK	162	if (!value)
ac27a0ec DK	163	return ERR_PTR(-ENOMEM);
617ba13b	164	retval = ext4_xattr_get(inode, name_index, "", value, retval);
ac27a0ec DK	165	}
ac27a0ec DK	166	if (retval > 0)
617ba13b	167	acl = ext4_acl_from_disk(value, retval);
ac27a0ec DK	168	else if (retval == -ENODATA \|\| retval == -ENOSYS)
	169	acl = NULL;
	170	else
	171	acl = ERR_PTR(retval);
	172	kfree(value);
	173
073aaa1b AV	174	if (!IS_ERR(acl))
073aaa1b AV	175	set_cached_acl(inode, type, acl);
2b2d6d01	176
ac27a0ec DK	177	return acl;
	178	}
	179
	180	/*
	181	* Set the access or default ACL of an inode.
	182	*
617ba13b	183	* inode->i_mutex: down unless called from ext4_new_inode
ac27a0ec DK	184	*/
ac27a0ec DK	185	static int
617ba13b	186	ext4_set_acl(handle_t handle, struct inode inode, int type,
ac27a0ec DK	187	struct posix_acl *acl)
ac27a0ec DK	188	{
ac27a0ec DK	189	int name_index;
	190	void *value = NULL;
	191	size_t size = 0;
	192	int error;
	193
	194	if (S_ISLNK(inode->i_mode))
	195	return -EOPNOTSUPP;
	196
2b2d6d01 TT	197	switch (type) {
	198	case ACL_TYPE_ACCESS:
	199	name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
	200	if (acl) {
	201	mode_t mode = inode->i_mode;
	202	error = posix_acl_equiv_mode(acl, &mode);
	203	if (error < 0)
	204	return error;
	205	else {
	206	inode->i_mode = mode;
c6ac12a6	207	inode->i_ctime = ext4_current_time(inode);
2b2d6d01 TT	208	ext4_mark_inode_dirty(handle, inode);
	209	if (error == 0)
	210	acl = NULL;
ac27a0ec	211	}
2b2d6d01 TT	212	}
2b2d6d01 TT	213	break;
ac27a0ec	214
2b2d6d01 TT	215	case ACL_TYPE_DEFAULT:
	216	name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
	217	if (!S_ISDIR(inode->i_mode))
	218	return acl ? -EACCES : 0;
	219	break;
ac27a0ec	220
2b2d6d01 TT	221	default:
2b2d6d01 TT	222	return -EINVAL;
ac27a0ec DK	223	}
ac27a0ec DK	224	if (acl) {
617ba13b	225	value = ext4_acl_to_disk(acl, &size);
ac27a0ec DK	226	if (IS_ERR(value))
	227	return (int)PTR_ERR(value);
	228	}
	229
617ba13b	230	error = ext4_xattr_set_handle(handle, inode, name_index, "",
ac27a0ec DK	231	value, size, 0);
	232
	233	kfree(value);
073aaa1b AV	234	if (!error)
073aaa1b AV	235	set_cached_acl(inode, type, acl);
2b2d6d01	236
ac27a0ec DK	237	return error;
	238	}
	239
1d5ccd1c	240	int
7e40145e	241	ext4_check_acl(struct inode *inode, int mask)
ac27a0ec	242	{
b74c79e9 NP	243	struct posix_acl *acl;
b74c79e9 NP	244
b74c79e9	245	acl = ext4_get_acl(inode, ACL_TYPE_ACCESS);
ac27a0ec DK	246	if (IS_ERR(acl))
	247	return PTR_ERR(acl);
	248	if (acl) {
	249	int error = posix_acl_permission(inode, acl, mask);
	250	posix_acl_release(acl);
	251	return error;
	252	}
	253
	254	return -EAGAIN;
	255	}
	256
ac27a0ec	257	/*
617ba13b	258	* Initialize the ACLs of a new inode. Called from ext4_new_inode.
ac27a0ec DK	259	*
	260	* dir->i_mutex: down
	261	* inode->i_mutex: up (access to inode is still exclusive)
	262	*/
	263	int
617ba13b	264	ext4_init_acl(handle_t handle, struct inode inode, struct inode *dir)
ac27a0ec DK	265	{
	266	struct posix_acl *acl = NULL;
	267	int error = 0;
	268
	269	if (!S_ISLNK(inode->i_mode)) {
	270	if (test_opt(dir->i_sb, POSIX_ACL)) {
617ba13b	271	acl = ext4_get_acl(dir, ACL_TYPE_DEFAULT);
ac27a0ec DK	272	if (IS_ERR(acl))
	273	return PTR_ERR(acl);
	274	}
	275	if (!acl)
ce3b0f8d	276	inode->i_mode &= ~current_umask();
ac27a0ec DK	277	}
	278	if (test_opt(inode->i_sb, POSIX_ACL) && acl) {
	279	struct posix_acl *clone;
	280	mode_t mode;
	281
	282	if (S_ISDIR(inode->i_mode)) {
617ba13b	283	error = ext4_set_acl(handle, inode,
ac27a0ec DK	284	ACL_TYPE_DEFAULT, acl);
	285	if (error)
	286	goto cleanup;
	287	}
216553c4	288	clone = posix_acl_clone(acl, GFP_NOFS);
ac27a0ec DK	289	error = -ENOMEM;
	290	if (!clone)
	291	goto cleanup;
	292
	293	mode = inode->i_mode;
	294	error = posix_acl_create_masq(clone, &mode);
	295	if (error >= 0) {
	296	inode->i_mode = mode;
	297	if (error > 0) {
	298	/* This is an extended ACL */
617ba13b	299	error = ext4_set_acl(handle, inode,
ac27a0ec DK	300	ACL_TYPE_ACCESS, clone);
	301	}
	302	}
	303	posix_acl_release(clone);
	304	}
	305	cleanup:
	306	posix_acl_release(acl);
	307	return error;
	308	}
	309
	310	/*
	311	* Does chmod for an inode that may have an Access Control List. The
	312	* inode->i_mode field must be updated to the desired value by the caller
	313	* before calling this function.
	314	* Returns 0 on success, or a negative error number.
	315	*
	316	* We change the ACL rather than storing some ACL entries in the file
	317	* mode permission bits (which would be more efficient), because that
	318	* would break once additional permissions (like ACL_APPEND, ACL_DELETE
	319	* for directories) are added. There are no more bits available in the
	320	* file mode.
	321	*
	322	* inode->i_mutex: down
	323	*/
	324	int
617ba13b	325	ext4_acl_chmod(struct inode *inode)
ac27a0ec DK	326	{
ac27a0ec DK	327	struct posix_acl acl, clone;
63f57933	328	int error;
ac27a0ec DK	329
	330	if (S_ISLNK(inode->i_mode))
	331	return -EOPNOTSUPP;
	332	if (!test_opt(inode->i_sb, POSIX_ACL))
	333	return 0;
617ba13b	334	acl = ext4_get_acl(inode, ACL_TYPE_ACCESS);
ac27a0ec DK	335	if (IS_ERR(acl) \|\| !acl)
	336	return PTR_ERR(acl);
	337	clone = posix_acl_clone(acl, GFP_KERNEL);
	338	posix_acl_release(acl);
	339	if (!clone)
	340	return -ENOMEM;
	341	error = posix_acl_chmod_masq(clone, inode->i_mode);
	342	if (!error) {
	343	handle_t *handle;
	344	int retries = 0;
	345
	346	retry:
617ba13b MC	347	handle = ext4_journal_start(inode,
617ba13b MC	348	EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
ac27a0ec DK	349	if (IS_ERR(handle)) {
ac27a0ec DK	350	error = PTR_ERR(handle);
617ba13b	351	ext4_std_error(inode->i_sb, error);
ac27a0ec DK	352	goto out;
ac27a0ec DK	353	}
617ba13b MC	354	error = ext4_set_acl(handle, inode, ACL_TYPE_ACCESS, clone);
617ba13b MC	355	ext4_journal_stop(handle);
ac27a0ec	356	if (error == -ENOSPC &&
617ba13b	357	ext4_should_retry_alloc(inode->i_sb, &retries))
ac27a0ec DK	358	goto retry;
	359	}
	360	out:
	361	posix_acl_release(clone);
	362	return error;
	363	}
	364
	365	/*
	366	* Extended attribute handlers
	367	*/
	368	static size_t
431547b3 CH	369	ext4_xattr_list_acl_access(struct dentry dentry, char list, size_t list_len,
431547b3 CH	370	const char *name, size_t name_len, int type)
ac27a0ec DK	371	{
	372	const size_t size = sizeof(POSIX_ACL_XATTR_ACCESS);
	373
431547b3	374	if (!test_opt(dentry->d_sb, POSIX_ACL))
ac27a0ec DK	375	return 0;
	376	if (list && size <= list_len)
	377	memcpy(list, POSIX_ACL_XATTR_ACCESS, size);
	378	return size;
	379	}
	380
	381	static size_t
431547b3 CH	382	ext4_xattr_list_acl_default(struct dentry dentry, char list, size_t list_len,
431547b3 CH	383	const char *name, size_t name_len, int type)
ac27a0ec DK	384	{
	385	const size_t size = sizeof(POSIX_ACL_XATTR_DEFAULT);
	386
431547b3	387	if (!test_opt(dentry->d_sb, POSIX_ACL))
ac27a0ec DK	388	return 0;
	389	if (list && size <= list_len)
	390	memcpy(list, POSIX_ACL_XATTR_DEFAULT, size);
	391	return size;
	392	}
	393
	394	static int
431547b3 CH	395	ext4_xattr_get_acl(struct dentry dentry, const char name, void *buffer,
431547b3 CH	396	size_t size, int type)
ac27a0ec DK	397	{
	398	struct posix_acl *acl;
	399	int error;
	400
431547b3 CH	401	if (strcmp(name, "") != 0)
	402	return -EINVAL;
	403	if (!test_opt(dentry->d_sb, POSIX_ACL))
ac27a0ec DK	404	return -EOPNOTSUPP;
ac27a0ec DK	405
431547b3	406	acl = ext4_get_acl(dentry->d_inode, type);
ac27a0ec DK	407	if (IS_ERR(acl))
	408	return PTR_ERR(acl);
	409	if (acl == NULL)
	410	return -ENODATA;
	411	error = posix_acl_to_xattr(acl, buffer, size);
	412	posix_acl_release(acl);
	413
	414	return error;
	415	}
	416
	417	static int
431547b3 CH	418	ext4_xattr_set_acl(struct dentry dentry, const char name, const void *value,
431547b3 CH	419	size_t size, int flags, int type)
ac27a0ec	420	{
431547b3	421	struct inode *inode = dentry->d_inode;
ac27a0ec DK	422	handle_t *handle;
	423	struct posix_acl *acl;
	424	int error, retries = 0;
	425
431547b3 CH	426	if (strcmp(name, "") != 0)
431547b3 CH	427	return -EINVAL;
ac27a0ec DK	428	if (!test_opt(inode->i_sb, POSIX_ACL))
ac27a0ec DK	429	return -EOPNOTSUPP;
2e149670	430	if (!inode_owner_or_capable(inode))
ac27a0ec DK	431	return -EPERM;
	432
	433	if (value) {
	434	acl = posix_acl_from_xattr(value, size);
	435	if (IS_ERR(acl))
	436	return PTR_ERR(acl);
	437	else if (acl) {
	438	error = posix_acl_valid(acl);
	439	if (error)
	440	goto release_and_out;
	441	}
	442	} else
	443	acl = NULL;
	444
	445	retry:
617ba13b	446	handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
ac27a0ec DK	447	if (IS_ERR(handle))
ac27a0ec DK	448	return PTR_ERR(handle);
617ba13b MC	449	error = ext4_set_acl(handle, inode, type, acl);
	450	ext4_journal_stop(handle);
	451	if (error == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
ac27a0ec DK	452	goto retry;
	453
	454	release_and_out:
	455	posix_acl_release(acl);
	456	return error;
	457	}
	458
11e27528	459	const struct xattr_handler ext4_xattr_acl_access_handler = {
ac27a0ec	460	.prefix = POSIX_ACL_XATTR_ACCESS,
431547b3	461	.flags = ACL_TYPE_ACCESS,
617ba13b	462	.list = ext4_xattr_list_acl_access,
431547b3 CH	463	.get = ext4_xattr_get_acl,
431547b3 CH	464	.set = ext4_xattr_set_acl,
ac27a0ec DK	465	};
ac27a0ec DK	466
11e27528	467	const struct xattr_handler ext4_xattr_acl_default_handler = {
ac27a0ec	468	.prefix = POSIX_ACL_XATTR_DEFAULT,
431547b3	469	.flags = ACL_TYPE_DEFAULT,
617ba13b	470	.list = ext4_xattr_list_acl_default,
431547b3 CH	471	.get = ext4_xattr_get_acl,
431547b3 CH	472	.set = ext4_xattr_set_acl,
ac27a0ec	473	};