[net-next-2.6.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);
}

static inline struct posix_acl *
ext4_iget_acl(struct inode *inode, struct posix_acl **i_acl)
{
	struct posix_acl *acl = ACCESS_ONCE(*i_acl);

	if (acl) {
		spin_lock(&inode->i_lock);
		acl = *i_acl;
		if (acl != ACL_NOT_CACHED)
			acl = posix_acl_dup(acl);
		spin_unlock(&inode->i_lock);
	}

	return acl;
}

static inline void
ext4_iset_acl(struct inode *inode, struct posix_acl **i_acl,
		struct posix_acl *acl)
{
	spin_lock(&inode->i_lock);
	if (*i_acl != ACL_NOT_CACHED)
		posix_acl_release(*i_acl);
	*i_acl = posix_acl_dup(acl);
	spin_unlock(&inode->i_lock);
}

/*
 * 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;

	switch (type) {
	case ACL_TYPE_ACCESS:
		acl = ext4_iget_acl(inode, &inode->i_acl);
		if (acl != ACL_NOT_CACHED)
			return acl;
		name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
		break;

	case ACL_TYPE_DEFAULT:
		acl = ext4_iget_acl(inode, &inode->i_default_acl);
		if (acl != ACL_NOT_CACHED)
			return acl;
		name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
		break;

	default:
		return ERR_PTR(-EINVAL);
	}
	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)) {
		switch (type) {
		case ACL_TYPE_ACCESS:
			ext4_iset_acl(inode, &inode->i_acl, acl);
			break;

		case ACL_TYPE_DEFAULT:
			ext4_iset_acl(inode, &inode->i_default_acl, acl);
			break;
		}
	}
	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) {
		switch (type) {
		case ACL_TYPE_ACCESS:
			ext4_iset_acl(inode, &inode->i_acl, acl);
			break;

		case ACL_TYPE_DEFAULT:
			ext4_iset_acl(inode, &inode->i_default_acl, acl);
			break;
		}
	}
	return error;
}

static 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;
}

int
ext4_permission(struct inode *inode, int mask)
{
	return generic_permission(inode, mask, ext4_check_acl);
}

/*
 * 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 inode *inode, char *list, size_t list_len,
			   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_len)
		memcpy(list, POSIX_ACL_XATTR_ACCESS, size);
	return size;
}

static size_t
ext4_xattr_list_acl_default(struct inode *inode, char *list, size_t list_len,
			    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_len)
		memcpy(list, POSIX_ACL_XATTR_DEFAULT, size);
	return size;
}

static int
ext4_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 = ext4_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
ext4_xattr_get_acl_access(struct inode *inode, const char *name,
			  void *buffer, size_t size)
{
	if (strcmp(name, "") != 0)
		return -EINVAL;
	return ext4_xattr_get_acl(inode, ACL_TYPE_ACCESS, buffer, size);
}

static int
ext4_xattr_get_acl_default(struct inode *inode, const char *name,
			   void *buffer, size_t size)
{
	if (strcmp(name, "") != 0)
		return -EINVAL;
	return ext4_xattr_get_acl(inode, ACL_TYPE_DEFAULT, buffer, size);
}

static int
ext4_xattr_set_acl(struct inode *inode, int type, const void *value,
		   size_t size)
{
	handle_t *handle;
	struct posix_acl *acl;
	int error, retries = 0;

	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;
}

static int
ext4_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 ext4_xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size);
}

static int
ext4_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 ext4_xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size);
}

struct xattr_handler ext4_xattr_acl_access_handler = {
	.prefix	= POSIX_ACL_XATTR_ACCESS,
	.list	= ext4_xattr_list_acl_access,
	.get	= ext4_xattr_get_acl_access,
	.set	= ext4_xattr_set_acl_access,
};

struct xattr_handler ext4_xattr_acl_default_handler = {
	.prefix	= POSIX_ACL_XATTR_DEFAULT,
	.list	= ext4_xattr_list_acl_default,
	.get	= ext4_xattr_get_acl_default,
	.set	= ext4_xattr_set_acl_default,
};
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
	129	static inline struct posix_acl *
617ba13b	130	ext4_iget_acl(struct inode inode, struct posix_acl *i_acl)
ac27a0ec	131	{
210ad6ae TT	132	struct posix_acl acl = ACCESS_ONCE(i_acl);
	133
	134	if (acl) {
	135	spin_lock(&inode->i_lock);
	136	acl = *i_acl;
d4bfe2f7	137	if (acl != ACL_NOT_CACHED)
210ad6ae TT	138	acl = posix_acl_dup(acl);
	139	spin_unlock(&inode->i_lock);
	140	}
ac27a0ec DK	141
	142	return acl;
	143	}
	144
	145	static inline void
617ba13b	146	ext4_iset_acl(struct inode inode, struct posix_acl *i_acl,
63f57933	147	struct posix_acl *acl)
ac27a0ec DK	148	{
ac27a0ec DK	149	spin_lock(&inode->i_lock);
d4bfe2f7	150	if (*i_acl != ACL_NOT_CACHED)
ac27a0ec DK	151	posix_acl_release(*i_acl);
	152	*i_acl = posix_acl_dup(acl);
	153	spin_unlock(&inode->i_lock);
	154	}
	155
	156	/*
	157	* Inode operation get_posix_acl().
	158	*
	159	* inode->i_mutex: don't care
	160	*/
	161	static struct posix_acl *
617ba13b	162	ext4_get_acl(struct inode *inode, int type)
ac27a0ec	163	{
ac27a0ec DK	164	int name_index;
	165	char *value = NULL;
	166	struct posix_acl *acl;
	167	int retval;
	168
	169	if (!test_opt(inode->i_sb, POSIX_ACL))
	170	return NULL;
	171
2b2d6d01 TT	172	switch (type) {
2b2d6d01 TT	173	case ACL_TYPE_ACCESS:
d4bfe2f7 AV	174	acl = ext4_iget_acl(inode, &inode->i_acl);
d4bfe2f7 AV	175	if (acl != ACL_NOT_CACHED)
2b2d6d01 TT	176	return acl;
	177	name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
	178	break;
	179
	180	case ACL_TYPE_DEFAULT:
d4bfe2f7 AV	181	acl = ext4_iget_acl(inode, &inode->i_default_acl);
d4bfe2f7 AV	182	if (acl != ACL_NOT_CACHED)
2b2d6d01 TT	183	return acl;
	184	name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
	185	break;
	186
	187	default:
	188	return ERR_PTR(-EINVAL);
ac27a0ec	189	}
617ba13b	190	retval = ext4_xattr_get(inode, name_index, "", NULL, 0);
ac27a0ec	191	if (retval > 0) {
216553c4	192	value = kmalloc(retval, GFP_NOFS);
ac27a0ec DK	193	if (!value)
ac27a0ec DK	194	return ERR_PTR(-ENOMEM);
617ba13b	195	retval = ext4_xattr_get(inode, name_index, "", value, retval);
ac27a0ec DK	196	}
ac27a0ec DK	197	if (retval > 0)
617ba13b	198	acl = ext4_acl_from_disk(value, retval);
ac27a0ec DK	199	else if (retval == -ENODATA \|\| retval == -ENOSYS)
	200	acl = NULL;
	201	else
	202	acl = ERR_PTR(retval);
	203	kfree(value);
	204
	205	if (!IS_ERR(acl)) {
2b2d6d01 TT	206	switch (type) {
2b2d6d01 TT	207	case ACL_TYPE_ACCESS:
d4bfe2f7	208	ext4_iset_acl(inode, &inode->i_acl, acl);
2b2d6d01 TT	209	break;
	210
	211	case ACL_TYPE_DEFAULT:
d4bfe2f7	212	ext4_iset_acl(inode, &inode->i_default_acl, acl);
2b2d6d01	213	break;
ac27a0ec DK	214	}
	215	}
	216	return acl;
	217	}
	218
	219	/*
	220	* Set the access or default ACL of an inode.
	221	*
617ba13b	222	* inode->i_mutex: down unless called from ext4_new_inode
ac27a0ec DK	223	*/
ac27a0ec DK	224	static int
617ba13b	225	ext4_set_acl(handle_t handle, struct inode inode, int type,
ac27a0ec DK	226	struct posix_acl *acl)
ac27a0ec DK	227	{
ac27a0ec DK	228	int name_index;
	229	void *value = NULL;
	230	size_t size = 0;
	231	int error;
	232
	233	if (S_ISLNK(inode->i_mode))
	234	return -EOPNOTSUPP;
	235
2b2d6d01 TT	236	switch (type) {
	237	case ACL_TYPE_ACCESS:
	238	name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
	239	if (acl) {
	240	mode_t mode = inode->i_mode;
	241	error = posix_acl_equiv_mode(acl, &mode);
	242	if (error < 0)
	243	return error;
	244	else {
	245	inode->i_mode = mode;
	246	ext4_mark_inode_dirty(handle, inode);
	247	if (error == 0)
	248	acl = NULL;
ac27a0ec	249	}
2b2d6d01 TT	250	}
2b2d6d01 TT	251	break;
ac27a0ec	252
2b2d6d01 TT	253	case ACL_TYPE_DEFAULT:
	254	name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
	255	if (!S_ISDIR(inode->i_mode))
	256	return acl ? -EACCES : 0;
	257	break;
ac27a0ec	258
2b2d6d01 TT	259	default:
2b2d6d01 TT	260	return -EINVAL;
ac27a0ec DK	261	}
ac27a0ec DK	262	if (acl) {
617ba13b	263	value = ext4_acl_to_disk(acl, &size);
ac27a0ec DK	264	if (IS_ERR(value))
	265	return (int)PTR_ERR(value);
	266	}
	267
617ba13b	268	error = ext4_xattr_set_handle(handle, inode, name_index, "",
ac27a0ec DK	269	value, size, 0);
	270
	271	kfree(value);
	272	if (!error) {
2b2d6d01 TT	273	switch (type) {
2b2d6d01 TT	274	case ACL_TYPE_ACCESS:
d4bfe2f7	275	ext4_iset_acl(inode, &inode->i_acl, acl);
2b2d6d01 TT	276	break;
	277
	278	case ACL_TYPE_DEFAULT:
d4bfe2f7	279	ext4_iset_acl(inode, &inode->i_default_acl, acl);
2b2d6d01	280	break;
ac27a0ec DK	281	}
	282	}
	283	return error;
	284	}
	285
	286	static int
617ba13b	287	ext4_check_acl(struct inode *inode, int mask)
ac27a0ec	288	{
617ba13b	289	struct posix_acl *acl = ext4_get_acl(inode, ACL_TYPE_ACCESS);
ac27a0ec DK	290
	291	if (IS_ERR(acl))
	292	return PTR_ERR(acl);
	293	if (acl) {
	294	int error = posix_acl_permission(inode, acl, mask);
	295	posix_acl_release(acl);
	296	return error;
	297	}
	298
	299	return -EAGAIN;
	300	}
	301
	302	int
e6305c43	303	ext4_permission(struct inode *inode, int mask)
ac27a0ec	304	{
617ba13b	305	return generic_permission(inode, mask, ext4_check_acl);
ac27a0ec DK	306	}
	307
	308	/*
617ba13b	309	* Initialize the ACLs of a new inode. Called from ext4_new_inode.
ac27a0ec DK	310	*
	311	* dir->i_mutex: down
	312	* inode->i_mutex: up (access to inode is still exclusive)
	313	*/
	314	int
617ba13b	315	ext4_init_acl(handle_t handle, struct inode inode, struct inode *dir)
ac27a0ec DK	316	{
	317	struct posix_acl *acl = NULL;
	318	int error = 0;
	319
	320	if (!S_ISLNK(inode->i_mode)) {
	321	if (test_opt(dir->i_sb, POSIX_ACL)) {
617ba13b	322	acl = ext4_get_acl(dir, ACL_TYPE_DEFAULT);
ac27a0ec DK	323	if (IS_ERR(acl))
	324	return PTR_ERR(acl);
	325	}
	326	if (!acl)
ce3b0f8d	327	inode->i_mode &= ~current_umask();
ac27a0ec DK	328	}
	329	if (test_opt(inode->i_sb, POSIX_ACL) && acl) {
	330	struct posix_acl *clone;
	331	mode_t mode;
	332
	333	if (S_ISDIR(inode->i_mode)) {
617ba13b	334	error = ext4_set_acl(handle, inode,
ac27a0ec DK	335	ACL_TYPE_DEFAULT, acl);
	336	if (error)
	337	goto cleanup;
	338	}
216553c4	339	clone = posix_acl_clone(acl, GFP_NOFS);
ac27a0ec DK	340	error = -ENOMEM;
	341	if (!clone)
	342	goto cleanup;
	343
	344	mode = inode->i_mode;
	345	error = posix_acl_create_masq(clone, &mode);
	346	if (error >= 0) {
	347	inode->i_mode = mode;
	348	if (error > 0) {
	349	/* This is an extended ACL */
617ba13b	350	error = ext4_set_acl(handle, inode,
ac27a0ec DK	351	ACL_TYPE_ACCESS, clone);
	352	}
	353	}
	354	posix_acl_release(clone);
	355	}
	356	cleanup:
	357	posix_acl_release(acl);
	358	return error;
	359	}
	360
	361	/*
	362	* Does chmod for an inode that may have an Access Control List. The
	363	* inode->i_mode field must be updated to the desired value by the caller
	364	* before calling this function.
	365	* Returns 0 on success, or a negative error number.
	366	*
	367	* We change the ACL rather than storing some ACL entries in the file
	368	* mode permission bits (which would be more efficient), because that
	369	* would break once additional permissions (like ACL_APPEND, ACL_DELETE
	370	* for directories) are added. There are no more bits available in the
	371	* file mode.
	372	*
	373	* inode->i_mutex: down
	374	*/
	375	int
617ba13b	376	ext4_acl_chmod(struct inode *inode)
ac27a0ec DK	377	{
ac27a0ec DK	378	struct posix_acl acl, clone;
63f57933	379	int error;
ac27a0ec DK	380
	381	if (S_ISLNK(inode->i_mode))
	382	return -EOPNOTSUPP;
	383	if (!test_opt(inode->i_sb, POSIX_ACL))
	384	return 0;
617ba13b	385	acl = ext4_get_acl(inode, ACL_TYPE_ACCESS);
ac27a0ec DK	386	if (IS_ERR(acl) \|\| !acl)
	387	return PTR_ERR(acl);
	388	clone = posix_acl_clone(acl, GFP_KERNEL);
	389	posix_acl_release(acl);
	390	if (!clone)
	391	return -ENOMEM;
	392	error = posix_acl_chmod_masq(clone, inode->i_mode);
	393	if (!error) {
	394	handle_t *handle;
	395	int retries = 0;
	396
	397	retry:
617ba13b MC	398	handle = ext4_journal_start(inode,
617ba13b MC	399	EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
ac27a0ec DK	400	if (IS_ERR(handle)) {
ac27a0ec DK	401	error = PTR_ERR(handle);
617ba13b	402	ext4_std_error(inode->i_sb, error);
ac27a0ec DK	403	goto out;
ac27a0ec DK	404	}
617ba13b MC	405	error = ext4_set_acl(handle, inode, ACL_TYPE_ACCESS, clone);
617ba13b MC	406	ext4_journal_stop(handle);
ac27a0ec	407	if (error == -ENOSPC &&
617ba13b	408	ext4_should_retry_alloc(inode->i_sb, &retries))
ac27a0ec DK	409	goto retry;
	410	}
	411	out:
	412	posix_acl_release(clone);
	413	return error;
	414	}
	415
	416	/*
	417	* Extended attribute handlers
	418	*/
	419	static size_t
617ba13b	420	ext4_xattr_list_acl_access(struct inode inode, char list, size_t list_len,
ac27a0ec DK	421	const char *name, size_t name_len)
	422	{
	423	const size_t size = sizeof(POSIX_ACL_XATTR_ACCESS);
	424
	425	if (!test_opt(inode->i_sb, POSIX_ACL))
	426	return 0;
	427	if (list && size <= list_len)
	428	memcpy(list, POSIX_ACL_XATTR_ACCESS, size);
	429	return size;
	430	}
	431
	432	static size_t
617ba13b	433	ext4_xattr_list_acl_default(struct inode inode, char list, size_t list_len,
ac27a0ec DK	434	const char *name, size_t name_len)
	435	{
	436	const size_t size = sizeof(POSIX_ACL_XATTR_DEFAULT);
	437
	438	if (!test_opt(inode->i_sb, POSIX_ACL))
	439	return 0;
	440	if (list && size <= list_len)
	441	memcpy(list, POSIX_ACL_XATTR_DEFAULT, size);
	442	return size;
	443	}
	444
	445	static int
617ba13b	446	ext4_xattr_get_acl(struct inode inode, int type, void buffer, size_t size)
ac27a0ec DK	447	{
	448	struct posix_acl *acl;
	449	int error;
	450
	451	if (!test_opt(inode->i_sb, POSIX_ACL))
	452	return -EOPNOTSUPP;
	453
617ba13b	454	acl = ext4_get_acl(inode, type);
ac27a0ec DK	455	if (IS_ERR(acl))
	456	return PTR_ERR(acl);
	457	if (acl == NULL)
	458	return -ENODATA;
	459	error = posix_acl_to_xattr(acl, buffer, size);
	460	posix_acl_release(acl);
	461
	462	return error;
	463	}
	464
	465	static int
617ba13b	466	ext4_xattr_get_acl_access(struct inode inode, const char name,
ac27a0ec DK	467	void *buffer, size_t size)
	468	{
	469	if (strcmp(name, "") != 0)
	470	return -EINVAL;
617ba13b	471	return ext4_xattr_get_acl(inode, ACL_TYPE_ACCESS, buffer, size);
ac27a0ec DK	472	}
	473
	474	static int
617ba13b	475	ext4_xattr_get_acl_default(struct inode inode, const char name,
ac27a0ec DK	476	void *buffer, size_t size)
	477	{
	478	if (strcmp(name, "") != 0)
	479	return -EINVAL;
617ba13b	480	return ext4_xattr_get_acl(inode, ACL_TYPE_DEFAULT, buffer, size);
ac27a0ec DK	481	}
	482
	483	static int
617ba13b	484	ext4_xattr_set_acl(struct inode inode, int type, const void value,
ac27a0ec DK	485	size_t size)
	486	{
	487	handle_t *handle;
	488	struct posix_acl *acl;
	489	int error, retries = 0;
	490
	491	if (!test_opt(inode->i_sb, POSIX_ACL))
	492	return -EOPNOTSUPP;
3bd858ab	493	if (!is_owner_or_cap(inode))
ac27a0ec DK	494	return -EPERM;
	495
	496	if (value) {
	497	acl = posix_acl_from_xattr(value, size);
	498	if (IS_ERR(acl))
	499	return PTR_ERR(acl);
	500	else if (acl) {
	501	error = posix_acl_valid(acl);
	502	if (error)
	503	goto release_and_out;
	504	}
	505	} else
	506	acl = NULL;
	507
	508	retry:
617ba13b	509	handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
ac27a0ec DK	510	if (IS_ERR(handle))
ac27a0ec DK	511	return PTR_ERR(handle);
617ba13b MC	512	error = ext4_set_acl(handle, inode, type, acl);
	513	ext4_journal_stop(handle);
	514	if (error == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
ac27a0ec DK	515	goto retry;
	516
	517	release_and_out:
	518	posix_acl_release(acl);
	519	return error;
	520	}
	521
	522	static int
617ba13b	523	ext4_xattr_set_acl_access(struct inode inode, const char name,
ac27a0ec DK	524	const void *value, size_t size, int flags)
	525	{
	526	if (strcmp(name, "") != 0)
	527	return -EINVAL;
617ba13b	528	return ext4_xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size);
ac27a0ec DK	529	}
	530
	531	static int
617ba13b	532	ext4_xattr_set_acl_default(struct inode inode, const char name,
ac27a0ec DK	533	const void *value, size_t size, int flags)
	534	{
	535	if (strcmp(name, "") != 0)
	536	return -EINVAL;
617ba13b	537	return ext4_xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size);
ac27a0ec DK	538	}
ac27a0ec DK	539
617ba13b	540	struct xattr_handler ext4_xattr_acl_access_handler = {
ac27a0ec	541	.prefix = POSIX_ACL_XATTR_ACCESS,
617ba13b MC	542	.list = ext4_xattr_list_acl_access,
	543	.get = ext4_xattr_get_acl_access,
	544	.set = ext4_xattr_set_acl_access,
ac27a0ec DK	545	};
ac27a0ec DK	546
617ba13b	547	struct xattr_handler ext4_xattr_acl_default_handler = {
ac27a0ec	548	.prefix = POSIX_ACL_XATTR_DEFAULT,
617ba13b MC	549	.list = ext4_xattr_list_acl_default,
	550	.get = ext4_xattr_get_acl_default,
	551	.set = ext4_xattr_set_acl_default,
ac27a0ec	552	};