[mirror_ubuntu-artful-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;
				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 = 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 (!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;

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;
}

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,
};

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;
	207	ext4_mark_inode_dirty(handle, inode);
	208	if (error == 0)
	209	acl = NULL;
ac27a0ec	210	}
2b2d6d01 TT	211	}
2b2d6d01 TT	212	break;
ac27a0ec	213
2b2d6d01 TT	214	case ACL_TYPE_DEFAULT:
	215	name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
	216	if (!S_ISDIR(inode->i_mode))
	217	return acl ? -EACCES : 0;
	218	break;
ac27a0ec	219
2b2d6d01 TT	220	default:
2b2d6d01 TT	221	return -EINVAL;
ac27a0ec DK	222	}
ac27a0ec DK	223	if (acl) {
617ba13b	224	value = ext4_acl_to_disk(acl, &size);
ac27a0ec DK	225	if (IS_ERR(value))
	226	return (int)PTR_ERR(value);
	227	}
	228
617ba13b	229	error = ext4_xattr_set_handle(handle, inode, name_index, "",
ac27a0ec DK	230	value, size, 0);
	231
	232	kfree(value);
073aaa1b AV	233	if (!error)
073aaa1b AV	234	set_cached_acl(inode, type, acl);
2b2d6d01	235
ac27a0ec DK	236	return error;
	237	}
	238
1d5ccd1c	239	int
617ba13b	240	ext4_check_acl(struct inode *inode, int mask)
ac27a0ec	241	{
617ba13b	242	struct posix_acl *acl = ext4_get_acl(inode, ACL_TYPE_ACCESS);
ac27a0ec DK	243
	244	if (IS_ERR(acl))
	245	return PTR_ERR(acl);
	246	if (acl) {
	247	int error = posix_acl_permission(inode, acl, mask);
	248	posix_acl_release(acl);
	249	return error;
	250	}
	251
	252	return -EAGAIN;
	253	}
	254
ac27a0ec	255	/*
617ba13b	256	* Initialize the ACLs of a new inode. Called from ext4_new_inode.
ac27a0ec DK	257	*
	258	* dir->i_mutex: down
	259	* inode->i_mutex: up (access to inode is still exclusive)
	260	*/
	261	int
617ba13b	262	ext4_init_acl(handle_t handle, struct inode inode, struct inode *dir)
ac27a0ec DK	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)) {
617ba13b	269	acl = ext4_get_acl(dir, ACL_TYPE_DEFAULT);
ac27a0ec DK	270	if (IS_ERR(acl))
	271	return PTR_ERR(acl);
	272	}
	273	if (!acl)
ce3b0f8d	274	inode->i_mode &= ~current_umask();
ac27a0ec DK	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)) {
617ba13b	281	error = ext4_set_acl(handle, inode,
ac27a0ec DK	282	ACL_TYPE_DEFAULT, acl);
	283	if (error)
	284	goto cleanup;
	285	}
216553c4	286	clone = posix_acl_clone(acl, GFP_NOFS);
ac27a0ec DK	287	error = -ENOMEM;
	288	if (!clone)
	289	goto cleanup;
	290
	291	mode = inode->i_mode;
	292	error = posix_acl_create_masq(clone, &mode);
	293	if (error >= 0) {
	294	inode->i_mode = mode;
	295	if (error > 0) {
	296	/* This is an extended ACL */
617ba13b	297	error = ext4_set_acl(handle, inode,
ac27a0ec DK	298	ACL_TYPE_ACCESS, clone);
	299	}
	300	}
	301	posix_acl_release(clone);
	302	}
	303	cleanup:
	304	posix_acl_release(acl);
	305	return error;
	306	}
	307
	308	/*
	309	* Does chmod for an inode that may have an Access Control List. The
	310	* inode->i_mode field must be updated to the desired value by the caller
	311	* before calling this function.
	312	* Returns 0 on success, or a negative error number.
	313	*
	314	* We change the ACL rather than storing some ACL entries in the file
	315	* mode permission bits (which would be more efficient), because that
	316	* would break once additional permissions (like ACL_APPEND, ACL_DELETE
	317	* for directories) are added. There are no more bits available in the
	318	* file mode.
	319	*
	320	* inode->i_mutex: down
	321	*/
	322	int
617ba13b	323	ext4_acl_chmod(struct inode *inode)
ac27a0ec DK	324	{
ac27a0ec DK	325	struct posix_acl acl, clone;
63f57933	326	int error;
ac27a0ec DK	327
	328	if (S_ISLNK(inode->i_mode))
	329	return -EOPNOTSUPP;
	330	if (!test_opt(inode->i_sb, POSIX_ACL))
	331	return 0;
617ba13b	332	acl = ext4_get_acl(inode, ACL_TYPE_ACCESS);
ac27a0ec DK	333	if (IS_ERR(acl) \|\| !acl)
	334	return PTR_ERR(acl);
	335	clone = posix_acl_clone(acl, GFP_KERNEL);
	336	posix_acl_release(acl);
	337	if (!clone)
	338	return -ENOMEM;
	339	error = posix_acl_chmod_masq(clone, inode->i_mode);
	340	if (!error) {
	341	handle_t *handle;
	342	int retries = 0;
	343
	344	retry:
617ba13b MC	345	handle = ext4_journal_start(inode,
617ba13b MC	346	EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
ac27a0ec DK	347	if (IS_ERR(handle)) {
ac27a0ec DK	348	error = PTR_ERR(handle);
617ba13b	349	ext4_std_error(inode->i_sb, error);
ac27a0ec DK	350	goto out;
ac27a0ec DK	351	}
617ba13b MC	352	error = ext4_set_acl(handle, inode, ACL_TYPE_ACCESS, clone);
617ba13b MC	353	ext4_journal_stop(handle);
ac27a0ec	354	if (error == -ENOSPC &&
617ba13b	355	ext4_should_retry_alloc(inode->i_sb, &retries))
ac27a0ec DK	356	goto retry;
	357	}
	358	out:
	359	posix_acl_release(clone);
	360	return error;
	361	}
	362
	363	/*
	364	* Extended attribute handlers
	365	*/
	366	static size_t
431547b3 CH	367	ext4_xattr_list_acl_access(struct dentry dentry, char list, size_t list_len,
431547b3 CH	368	const char *name, size_t name_len, int type)
ac27a0ec DK	369	{
	370	const size_t size = sizeof(POSIX_ACL_XATTR_ACCESS);
	371
431547b3	372	if (!test_opt(dentry->d_sb, POSIX_ACL))
ac27a0ec DK	373	return 0;
	374	if (list && size <= list_len)
	375	memcpy(list, POSIX_ACL_XATTR_ACCESS, size);
	376	return size;
	377	}
	378
	379	static size_t
431547b3 CH	380	ext4_xattr_list_acl_default(struct dentry dentry, char list, size_t list_len,
431547b3 CH	381	const char *name, size_t name_len, int type)
ac27a0ec DK	382	{
	383	const size_t size = sizeof(POSIX_ACL_XATTR_DEFAULT);
	384
431547b3	385	if (!test_opt(dentry->d_sb, POSIX_ACL))
ac27a0ec DK	386	return 0;
	387	if (list && size <= list_len)
	388	memcpy(list, POSIX_ACL_XATTR_DEFAULT, size);
	389	return size;
	390	}
	391
	392	static int
431547b3 CH	393	ext4_xattr_get_acl(struct dentry dentry, const char name, void *buffer,
431547b3 CH	394	size_t size, int type)
ac27a0ec DK	395	{
	396	struct posix_acl *acl;
	397	int error;
	398
431547b3 CH	399	if (strcmp(name, "") != 0)
	400	return -EINVAL;
	401	if (!test_opt(dentry->d_sb, POSIX_ACL))
ac27a0ec DK	402	return -EOPNOTSUPP;
ac27a0ec DK	403
431547b3	404	acl = ext4_get_acl(dentry->d_inode, type);
ac27a0ec DK	405	if (IS_ERR(acl))
	406	return PTR_ERR(acl);
	407	if (acl == NULL)
	408	return -ENODATA;
	409	error = posix_acl_to_xattr(acl, buffer, size);
	410	posix_acl_release(acl);
	411
	412	return error;
	413	}
	414
	415	static int
431547b3 CH	416	ext4_xattr_set_acl(struct dentry dentry, const char name, const void *value,
431547b3 CH	417	size_t size, int flags, int type)
ac27a0ec	418	{
431547b3	419	struct inode *inode = dentry->d_inode;
ac27a0ec DK	420	handle_t *handle;
	421	struct posix_acl *acl;
	422	int error, retries = 0;
	423
431547b3 CH	424	if (strcmp(name, "") != 0)
431547b3 CH	425	return -EINVAL;
ac27a0ec DK	426	if (!test_opt(inode->i_sb, POSIX_ACL))
ac27a0ec DK	427	return -EOPNOTSUPP;
3bd858ab	428	if (!is_owner_or_cap(inode))
ac27a0ec DK	429	return -EPERM;
	430
	431	if (value) {
	432	acl = posix_acl_from_xattr(value, size);
	433	if (IS_ERR(acl))
	434	return PTR_ERR(acl);
	435	else if (acl) {
	436	error = posix_acl_valid(acl);
	437	if (error)
	438	goto release_and_out;
	439	}
	440	} else
	441	acl = NULL;
	442
	443	retry:
617ba13b	444	handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
ac27a0ec DK	445	if (IS_ERR(handle))
ac27a0ec DK	446	return PTR_ERR(handle);
617ba13b MC	447	error = ext4_set_acl(handle, inode, type, acl);
	448	ext4_journal_stop(handle);
	449	if (error == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
ac27a0ec DK	450	goto retry;
	451
	452	release_and_out:
	453	posix_acl_release(acl);
	454	return error;
	455	}
	456
617ba13b	457	struct xattr_handler ext4_xattr_acl_access_handler = {
ac27a0ec	458	.prefix = POSIX_ACL_XATTR_ACCESS,
431547b3	459	.flags = ACL_TYPE_ACCESS,
617ba13b	460	.list = ext4_xattr_list_acl_access,
431547b3 CH	461	.get = ext4_xattr_get_acl,
431547b3 CH	462	.set = ext4_xattr_set_acl,
ac27a0ec DK	463	};
ac27a0ec DK	464
617ba13b	465	struct xattr_handler ext4_xattr_acl_default_handler = {
ac27a0ec	466	.prefix = POSIX_ACL_XATTR_DEFAULT,
431547b3	467	.flags = ACL_TYPE_DEFAULT,
617ba13b	468	.list = ext4_xattr_list_acl_default,
431547b3 CH	469	.get = ext4_xattr_get_acl,
431547b3 CH	470	.set = ext4_xattr_set_acl,
ac27a0ec	471	};