[linux-2.6-block.git] / fs / ext3 / acl.c

/*
 * linux/fs/ext3/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 <linux/ext3_jbd.h>
#include <linux/ext3_fs.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);
				acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
				break;

			case ACL_USER:
			case ACL_GROUP:
				value = (char *)value + sizeof(ext3_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 *
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++) {
		ext3_acl_entry *entry = (ext3_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(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);
}

static inline struct posix_acl *
ext3_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 != EXT3_ACL_NOT_CACHED)
			acl = posix_acl_dup(acl);
		spin_unlock(&inode->i_lock);
	}

	return acl;
}

static inline void
ext3_iset_acl(struct inode *inode, struct posix_acl **i_acl,
                  struct posix_acl *acl)
{
	spin_lock(&inode->i_lock);
	if (*i_acl != EXT3_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 *
ext3_get_acl(struct inode *inode, int type)
{
	struct ext3_inode_info *ei = EXT3_I(inode);
	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 = ext3_iget_acl(inode, &ei->i_acl);
			if (acl != EXT3_ACL_NOT_CACHED)
				return acl;
			name_index = EXT3_XATTR_INDEX_POSIX_ACL_ACCESS;
			break;

		case ACL_TYPE_DEFAULT:
			acl = ext3_iget_acl(inode, &ei->i_default_acl);
			if (acl != EXT3_ACL_NOT_CACHED)
				return acl;
			name_index = EXT3_XATTR_INDEX_POSIX_ACL_DEFAULT;
			break;

		default:
			return ERR_PTR(-EINVAL);
	}
	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)) {
		switch(type) {
			case ACL_TYPE_ACCESS:
				ext3_iset_acl(inode, &ei->i_acl, acl);
				break;

			case ACL_TYPE_DEFAULT:
				ext3_iset_acl(inode, &ei->i_default_acl, acl);
				break;
		}
	}
	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)
{
	struct ext3_inode_info *ei = EXT3_I(inode);
	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) {
				mode_t mode = inode->i_mode;
				error = posix_acl_equiv_mode(acl, &mode);
				if (error < 0)
					return error;
				else {
					inode->i_mode = mode;
					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) {
		switch(type) {
			case ACL_TYPE_ACCESS:
				ext3_iset_acl(inode, &ei->i_acl, acl);
				break;

			case ACL_TYPE_DEFAULT:
				ext3_iset_acl(inode, &ei->i_default_acl, acl);
				break;
		}
	}
	return error;
}

static int
ext3_check_acl(struct inode *inode, int mask)
{
	struct posix_acl *acl = ext3_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
ext3_permission(struct inode *inode, int mask)
{
	return generic_permission(inode, mask, ext3_check_acl);
}

/*
 * 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) {
		struct posix_acl *clone;
		mode_t mode;

		if (S_ISDIR(inode->i_mode)) {
			error = ext3_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 = ext3_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
ext3_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 = ext3_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 = 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, clone);
		ext3_journal_stop(handle);
		if (error == -ENOSPC &&
		    ext3_should_retry_alloc(inode->i_sb, &retries))
			goto retry;
	}
out:
	posix_acl_release(clone);
	return error;
}

/*
 * Extended attribute handlers
 */
static size_t
ext3_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
ext3_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
ext3_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 = ext3_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
ext3_xattr_get_acl_access(struct inode *inode, const char *name,
			  void *buffer, size_t size)
{
	if (strcmp(name, "") != 0)
		return -EINVAL;
	return ext3_xattr_get_acl(inode, ACL_TYPE_ACCESS, buffer, size);
}

static int
ext3_xattr_get_acl_default(struct inode *inode, const char *name,
			   void *buffer, size_t size)
{
	if (strcmp(name, "") != 0)
		return -EINVAL;
	return ext3_xattr_get_acl(inode, ACL_TYPE_DEFAULT, buffer, size);
}

static int
ext3_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 = 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;
}

static int
ext3_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 ext3_xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size);
}

static int
ext3_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 ext3_xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size);
}

struct xattr_handler ext3_xattr_acl_access_handler = {
	.prefix	= POSIX_ACL_XATTR_ACCESS,
	.list	= ext3_xattr_list_acl_access,
	.get	= ext3_xattr_get_acl_access,
	.set	= ext3_xattr_set_acl_access,
};

struct xattr_handler ext3_xattr_acl_default_handler = {
	.prefix	= POSIX_ACL_XATTR_DEFAULT,
	.list	= ext3_xattr_list_acl_default,
	.get	= ext3_xattr_get_acl_default,
	.set	= ext3_xattr_set_acl_default,
};
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
	7	#include <linux/init.h>
	8	#include <linux/sched.h>
	9	#include <linux/slab.h>
16f7e0fe	10	#include <linux/capability.h>
1da177e4 LT	11	#include <linux/fs.h>
	12	#include <linux/ext3_jbd.h>
	13	#include <linux/ext3_fs.h>
	14	#include "xattr.h"
	15	#include "acl.h"
	16
	17	/*
	18	* Convert from filesystem to in-memory representation.
	19	*/
	20	static struct posix_acl *
	21	ext3_acl_from_disk(const void *value, size_t size)
	22	{
	23	const char end = (char )value + size;
	24	int n, count;
	25	struct posix_acl *acl;
	26
	27	if (!value)
	28	return NULL;
	29	if (size < sizeof(ext3_acl_header))
	30	return ERR_PTR(-EINVAL);
	31	if (((ext3_acl_header *)value)->a_version !=
	32	cpu_to_le32(EXT3_ACL_VERSION))
	33	return ERR_PTR(-EINVAL);
	34	value = (char *)value + sizeof(ext3_acl_header);
	35	count = ext3_acl_count(size);
	36	if (count < 0)
	37	return ERR_PTR(-EINVAL);
	38	if (count == 0)
	39	return NULL;
c587f0c0	40	acl = posix_acl_alloc(count, GFP_NOFS);
1da177e4 LT	41	if (!acl)
	42	return ERR_PTR(-ENOMEM);
	43	for (n=0; n < count; n++) {
	44	ext3_acl_entry *entry =
	45	(ext3_acl_entry *)value;
	46	if ((char *)value + sizeof(ext3_acl_entry_short) > end)
	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);
	50	switch(acl->a_entries[n].e_tag) {
	51	case ACL_USER_OBJ:
	52	case ACL_GROUP_OBJ:
	53	case ACL_MASK:
	54	case ACL_OTHER:
	55	value = (char *)value +
	56	sizeof(ext3_acl_entry_short);
	57	acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
	58	break;
	59
	60	case ACL_USER:
	61	case ACL_GROUP:
	62	value = (char *)value + sizeof(ext3_acl_entry);
	63	if ((char *)value > end)
	64	goto fail;
	65	acl->a_entries[n].e_id =
	66	le32_to_cpu(entry->e_id);
	67	break;
	68
	69	default:
	70	goto fail;
	71	}
	72	}
	73	if (value != end)
	74	goto fail;
	75	return acl;
	76
	77	fail:
	78	posix_acl_release(acl);
	79	return ERR_PTR(-EINVAL);
	80	}
	81
	82	/*
	83	* Convert from in-memory to filesystem representation.
	84	*/
	85	static void *
	86	ext3_acl_to_disk(const struct posix_acl acl, size_t size)
	87	{
	88	ext3_acl_header *ext_acl;
	89	char *e;
	90	size_t n;
	91
	92	*size = ext3_acl_size(acl->a_count);
f52720ca	93	ext_acl = kmalloc(sizeof(ext3_acl_header) + acl->a_count *
c587f0c0	94	sizeof(ext3_acl_entry), GFP_NOFS);
1da177e4 LT	95	if (!ext_acl)
	96	return ERR_PTR(-ENOMEM);
	97	ext_acl->a_version = cpu_to_le32(EXT3_ACL_VERSION);
	98	e = (char *)ext_acl + sizeof(ext3_acl_header);
	99	for (n=0; n < acl->a_count; n++) {
	100	ext3_acl_entry entry = (ext3_acl_entry )e;
	101	entry->e_tag = cpu_to_le16(acl->a_entries[n].e_tag);
	102	entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
	103	switch(acl->a_entries[n].e_tag) {
	104	case ACL_USER:
	105	case ACL_GROUP:
	106	entry->e_id =
	107	cpu_to_le32(acl->a_entries[n].e_id);
	108	e += sizeof(ext3_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(ext3_acl_entry_short);
	116	break;
	117
	118	default:
	119	goto fail;
	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 *
	130	ext3_iget_acl(struct inode inode, struct posix_acl *i_acl)
	131	{
9c64daff	132	struct posix_acl acl = ACCESS_ONCE(i_acl);
1da177e4	133
9c64daff LT	134	if (acl) {
	135	spin_lock(&inode->i_lock);
	136	acl = *i_acl;
	137	if (acl != EXT3_ACL_NOT_CACHED)
	138	acl = posix_acl_dup(acl);
	139	spin_unlock(&inode->i_lock);
	140	}
1da177e4 LT	141
	142	return acl;
	143	}
	144
	145	static inline void
	146	ext3_iset_acl(struct inode inode, struct posix_acl *i_acl,
	147	struct posix_acl *acl)
	148	{
	149	spin_lock(&inode->i_lock);
	150	if (*i_acl != EXT3_ACL_NOT_CACHED)
	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	*
1b1dcc1b	159	* inode->i_mutex: don't care
1da177e4 LT	160	*/
	161	static struct posix_acl *
	162	ext3_get_acl(struct inode *inode, int type)
	163	{
	164	struct ext3_inode_info *ei = EXT3_I(inode);
	165	int name_index;
	166	char *value = NULL;
	167	struct posix_acl *acl;
	168	int retval;
	169
	170	if (!test_opt(inode->i_sb, POSIX_ACL))
	171	return NULL;
	172
	173	switch(type) {
	174	case ACL_TYPE_ACCESS:
	175	acl = ext3_iget_acl(inode, &ei->i_acl);
	176	if (acl != EXT3_ACL_NOT_CACHED)
	177	return acl;
	178	name_index = EXT3_XATTR_INDEX_POSIX_ACL_ACCESS;
	179	break;
	180
	181	case ACL_TYPE_DEFAULT:
	182	acl = ext3_iget_acl(inode, &ei->i_default_acl);
	183	if (acl != EXT3_ACL_NOT_CACHED)
	184	return acl;
	185	name_index = EXT3_XATTR_INDEX_POSIX_ACL_DEFAULT;
	186	break;
	187
	188	default:
	189	return ERR_PTR(-EINVAL);
	190	}
	191	retval = ext3_xattr_get(inode, name_index, "", NULL, 0);
	192	if (retval > 0) {
c587f0c0	193	value = kmalloc(retval, GFP_NOFS);
1da177e4 LT	194	if (!value)
	195	return ERR_PTR(-ENOMEM);
	196	retval = ext3_xattr_get(inode, name_index, "", value, retval);
	197	}
	198	if (retval > 0)
	199	acl = ext3_acl_from_disk(value, retval);
	200	else if (retval == -ENODATA \|\| retval == -ENOSYS)
	201	acl = NULL;
	202	else
	203	acl = ERR_PTR(retval);
	204	kfree(value);
	205
	206	if (!IS_ERR(acl)) {
	207	switch(type) {
	208	case ACL_TYPE_ACCESS:
	209	ext3_iset_acl(inode, &ei->i_acl, acl);
	210	break;
	211
	212	case ACL_TYPE_DEFAULT:
	213	ext3_iset_acl(inode, &ei->i_default_acl, acl);
	214	break;
	215	}
	216	}
	217	return acl;
	218	}
	219
	220	/*
	221	* Set the access or default ACL of an inode.
	222	*
1b1dcc1b	223	* inode->i_mutex: down unless called from ext3_new_inode
1da177e4 LT	224	*/
	225	static int
	226	ext3_set_acl(handle_t handle, struct inode inode, int type,
	227	struct posix_acl *acl)
	228	{
	229	struct ext3_inode_info *ei = EXT3_I(inode);
	230	int name_index;
	231	void *value = NULL;
dfa08592	232	size_t size = 0;
1da177e4 LT	233	int error;
	234
	235	if (S_ISLNK(inode->i_mode))
	236	return -EOPNOTSUPP;
	237
	238	switch(type) {
	239	case ACL_TYPE_ACCESS:
	240	name_index = EXT3_XATTR_INDEX_POSIX_ACL_ACCESS;
	241	if (acl) {
	242	mode_t mode = inode->i_mode;
	243	error = posix_acl_equiv_mode(acl, &mode);
	244	if (error < 0)
	245	return error;
	246	else {
	247	inode->i_mode = mode;
	248	ext3_mark_inode_dirty(handle, inode);
	249	if (error == 0)
	250	acl = NULL;
	251	}
	252	}
	253	break;
	254
	255	case ACL_TYPE_DEFAULT:
	256	name_index = EXT3_XATTR_INDEX_POSIX_ACL_DEFAULT;
	257	if (!S_ISDIR(inode->i_mode))
	258	return acl ? -EACCES : 0;
	259	break;
	260
	261	default:
	262	return -EINVAL;
	263	}
e9ad5620	264	if (acl) {
1da177e4 LT	265	value = ext3_acl_to_disk(acl, &size);
	266	if (IS_ERR(value))
	267	return (int)PTR_ERR(value);
	268	}
	269
	270	error = ext3_xattr_set_handle(handle, inode, name_index, "",
	271	value, size, 0);
	272
	273	kfree(value);
	274	if (!error) {
	275	switch(type) {
	276	case ACL_TYPE_ACCESS:
	277	ext3_iset_acl(inode, &ei->i_acl, acl);
	278	break;
	279
	280	case ACL_TYPE_DEFAULT:
	281	ext3_iset_acl(inode, &ei->i_default_acl, acl);
	282	break;
	283	}
	284	}
	285	return error;
	286	}
	287
	288	static int
	289	ext3_check_acl(struct inode *inode, int mask)
	290	{
	291	struct posix_acl *acl = ext3_get_acl(inode, ACL_TYPE_ACCESS);
	292
e493073d	293	if (IS_ERR(acl))
e493073d	294	return PTR_ERR(acl);
1da177e4 LT	295	if (acl) {
	296	int error = posix_acl_permission(inode, acl, mask);
	297	posix_acl_release(acl);
	298	return error;
	299	}
	300
	301	return -EAGAIN;
	302	}
	303
	304	int
e6305c43	305	ext3_permission(struct inode *inode, int mask)
1da177e4 LT	306	{
	307	return generic_permission(inode, mask, ext3_check_acl);
	308	}
	309
	310	/*
	311	* Initialize the ACLs of a new inode. Called from ext3_new_inode.
	312	*
1b1dcc1b JS	313	* dir->i_mutex: down
1b1dcc1b JS	314	* inode->i_mutex: up (access to inode is still exclusive)
1da177e4 LT	315	*/
	316	int
	317	ext3_init_acl(handle_t handle, struct inode inode, struct inode *dir)
	318	{
	319	struct posix_acl *acl = NULL;
	320	int error = 0;
	321
	322	if (!S_ISLNK(inode->i_mode)) {
	323	if (test_opt(dir->i_sb, POSIX_ACL)) {
	324	acl = ext3_get_acl(dir, ACL_TYPE_DEFAULT);
	325	if (IS_ERR(acl))
	326	return PTR_ERR(acl);
	327	}
	328	if (!acl)
ce3b0f8d	329	inode->i_mode &= ~current_umask();
1da177e4 LT	330	}
	331	if (test_opt(inode->i_sb, POSIX_ACL) && acl) {
	332	struct posix_acl *clone;
	333	mode_t mode;
	334
	335	if (S_ISDIR(inode->i_mode)) {
	336	error = ext3_set_acl(handle, inode,
	337	ACL_TYPE_DEFAULT, acl);
	338	if (error)
	339	goto cleanup;
	340	}
c587f0c0	341	clone = posix_acl_clone(acl, GFP_NOFS);
1da177e4 LT	342	error = -ENOMEM;
	343	if (!clone)
	344	goto cleanup;
	345
	346	mode = inode->i_mode;
	347	error = posix_acl_create_masq(clone, &mode);
	348	if (error >= 0) {
	349	inode->i_mode = mode;
	350	if (error > 0) {
	351	/* This is an extended ACL */
	352	error = ext3_set_acl(handle, inode,
	353	ACL_TYPE_ACCESS, clone);
	354	}
	355	}
	356	posix_acl_release(clone);
	357	}
	358	cleanup:
	359	posix_acl_release(acl);
	360	return error;
	361	}
	362
	363	/*
	364	* Does chmod for an inode that may have an Access Control List. The
	365	* inode->i_mode field must be updated to the desired value by the caller
	366	* before calling this function.
	367	* Returns 0 on success, or a negative error number.
	368	*
	369	* We change the ACL rather than storing some ACL entries in the file
	370	* mode permission bits (which would be more efficient), because that
	371	* would break once additional permissions (like ACL_APPEND, ACL_DELETE
	372	* for directories) are added. There are no more bits available in the
	373	* file mode.
	374	*
1b1dcc1b	375	* inode->i_mutex: down
1da177e4 LT	376	*/
	377	int
	378	ext3_acl_chmod(struct inode *inode)
	379	{
	380	struct posix_acl acl, clone;
	381	int error;
	382
	383	if (S_ISLNK(inode->i_mode))
	384	return -EOPNOTSUPP;
	385	if (!test_opt(inode->i_sb, POSIX_ACL))
	386	return 0;
	387	acl = ext3_get_acl(inode, ACL_TYPE_ACCESS);
	388	if (IS_ERR(acl) \|\| !acl)
	389	return PTR_ERR(acl);
	390	clone = posix_acl_clone(acl, GFP_KERNEL);
	391	posix_acl_release(acl);
	392	if (!clone)
	393	return -ENOMEM;
	394	error = posix_acl_chmod_masq(clone, inode->i_mode);
	395	if (!error) {
	396	handle_t *handle;
	397	int retries = 0;
	398
	399	retry:
1f54587b JK	400	handle = ext3_journal_start(inode,
1f54587b JK	401	EXT3_DATA_TRANS_BLOCKS(inode->i_sb));
1da177e4 LT	402	if (IS_ERR(handle)) {
	403	error = PTR_ERR(handle);
	404	ext3_std_error(inode->i_sb, error);
	405	goto out;
	406	}
	407	error = ext3_set_acl(handle, inode, ACL_TYPE_ACCESS, clone);
	408	ext3_journal_stop(handle);
	409	if (error == -ENOSPC &&
	410	ext3_should_retry_alloc(inode->i_sb, &retries))
	411	goto retry;
	412	}
	413	out:
	414	posix_acl_release(clone);
	415	return error;
	416	}
	417
	418	/*
	419	* Extended attribute handlers
	420	*/
	421	static size_t
	422	ext3_xattr_list_acl_access(struct inode inode, char list, size_t list_len,
	423	const char *name, size_t name_len)
	424	{
9a59f452	425	const size_t size = sizeof(POSIX_ACL_XATTR_ACCESS);
1da177e4 LT	426
	427	if (!test_opt(inode->i_sb, POSIX_ACL))
	428	return 0;
	429	if (list && size <= list_len)
9a59f452	430	memcpy(list, POSIX_ACL_XATTR_ACCESS, size);
1da177e4 LT	431	return size;
	432	}
	433
	434	static size_t
	435	ext3_xattr_list_acl_default(struct inode inode, char list, size_t list_len,
	436	const char *name, size_t name_len)
	437	{
9a59f452	438	const size_t size = sizeof(POSIX_ACL_XATTR_DEFAULT);
1da177e4 LT	439
	440	if (!test_opt(inode->i_sb, POSIX_ACL))
	441	return 0;
	442	if (list && size <= list_len)
9a59f452	443	memcpy(list, POSIX_ACL_XATTR_DEFAULT, size);
1da177e4 LT	444	return size;
	445	}
	446
	447	static int
	448	ext3_xattr_get_acl(struct inode inode, int type, void buffer, size_t size)
	449	{
	450	struct posix_acl *acl;
	451	int error;
	452
	453	if (!test_opt(inode->i_sb, POSIX_ACL))
	454	return -EOPNOTSUPP;
	455
	456	acl = ext3_get_acl(inode, type);
	457	if (IS_ERR(acl))
	458	return PTR_ERR(acl);
	459	if (acl == NULL)
	460	return -ENODATA;
	461	error = posix_acl_to_xattr(acl, buffer, size);
	462	posix_acl_release(acl);
	463
	464	return error;
	465	}
	466
	467	static int
	468	ext3_xattr_get_acl_access(struct inode inode, const char name,
	469	void *buffer, size_t size)
	470	{
	471	if (strcmp(name, "") != 0)
	472	return -EINVAL;
	473	return ext3_xattr_get_acl(inode, ACL_TYPE_ACCESS, buffer, size);
	474	}
	475
	476	static int
	477	ext3_xattr_get_acl_default(struct inode inode, const char name,
	478	void *buffer, size_t size)
	479	{
	480	if (strcmp(name, "") != 0)
	481	return -EINVAL;
	482	return ext3_xattr_get_acl(inode, ACL_TYPE_DEFAULT, buffer, size);
	483	}
	484
	485	static int
	486	ext3_xattr_set_acl(struct inode inode, int type, const void value,
	487	size_t size)
	488	{
	489	handle_t *handle;
	490	struct posix_acl *acl;
	491	int error, retries = 0;
	492
	493	if (!test_opt(inode->i_sb, POSIX_ACL))
	494	return -EOPNOTSUPP;
3bd858ab	495	if (!is_owner_or_cap(inode))
1da177e4 LT	496	return -EPERM;
	497
	498	if (value) {
	499	acl = posix_acl_from_xattr(value, size);
	500	if (IS_ERR(acl))
	501	return PTR_ERR(acl);
	502	else if (acl) {
	503	error = posix_acl_valid(acl);
	504	if (error)
	505	goto release_and_out;
	506	}
	507	} else
	508	acl = NULL;
	509
	510	retry:
1f54587b	511	handle = ext3_journal_start(inode, EXT3_DATA_TRANS_BLOCKS(inode->i_sb));
1da177e4 LT	512	if (IS_ERR(handle))
	513	return PTR_ERR(handle);
	514	error = ext3_set_acl(handle, inode, type, acl);
	515	ext3_journal_stop(handle);
	516	if (error == -ENOSPC && ext3_should_retry_alloc(inode->i_sb, &retries))
	517	goto retry;
	518
	519	release_and_out:
	520	posix_acl_release(acl);
	521	return error;
	522	}
	523
	524	static int
	525	ext3_xattr_set_acl_access(struct inode inode, const char name,
	526	const void *value, size_t size, int flags)
	527	{
	528	if (strcmp(name, "") != 0)
	529	return -EINVAL;
	530	return ext3_xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size);
	531	}
	532
	533	static int
	534	ext3_xattr_set_acl_default(struct inode inode, const char name,
	535	const void *value, size_t size, int flags)
	536	{
	537	if (strcmp(name, "") != 0)
	538	return -EINVAL;
	539	return ext3_xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size);
	540	}
	541
	542	struct xattr_handler ext3_xattr_acl_access_handler = {
9a59f452	543	.prefix = POSIX_ACL_XATTR_ACCESS,
1da177e4 LT	544	.list = ext3_xattr_list_acl_access,
	545	.get = ext3_xattr_get_acl_access,
	546	.set = ext3_xattr_set_acl_access,
	547	};
	548
	549	struct xattr_handler ext3_xattr_acl_default_handler = {
9a59f452	550	.prefix = POSIX_ACL_XATTR_DEFAULT,
1da177e4 LT	551	.list = ext3_xattr_list_acl_default,
	552	.get = ext3_xattr_get_acl_default,
	553	.set = ext3_xattr_set_acl_default,
	554	};