[GitHub/mt8127/android_kernel_alcatel_ttab.git] / fs / btrfs / xattr.c

/*
 * Copyright (C) 2007 Red Hat.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License v2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 */

#include <linux/init.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/rwsem.h>
#include <linux/xattr.h>
#include <linux/security.h>
#include "ctree.h"
#include "btrfs_inode.h"
#include "transaction.h"
#include "xattr.h"
#include "disk-io.h"


ssize_t __btrfs_getxattr(struct inode *inode, const char *name,
				void *buffer, size_t size)
{
	struct btrfs_dir_item *di;
	struct btrfs_root *root = BTRFS_I(inode)->root;
	struct btrfs_path *path;
	struct extent_buffer *leaf;
	int ret = 0;
	unsigned long data_ptr;

	path = btrfs_alloc_path();
	if (!path)
		return -ENOMEM;

	/* lookup the xattr by name */
	di = btrfs_lookup_xattr(NULL, root, path, btrfs_ino(inode), name,
				strlen(name), 0);
	if (!di) {
		ret = -ENODATA;
		goto out;
	} else if (IS_ERR(di)) {
		ret = PTR_ERR(di);
		goto out;
	}

	leaf = path->nodes[0];
	/* if size is 0, that means we want the size of the attr */
	if (!size) {
		ret = btrfs_dir_data_len(leaf, di);
		goto out;
	}

	/* now get the data out of our dir_item */
	if (btrfs_dir_data_len(leaf, di) > size) {
		ret = -ERANGE;
		goto out;
	}

	/*
	 * The way things are packed into the leaf is like this
	 * |struct btrfs_dir_item|name|data|
	 * where name is the xattr name, so security.foo, and data is the
	 * content of the xattr.  data_ptr points to the location in memory
	 * where the data starts in the in memory leaf
	 */
	data_ptr = (unsigned long)((char *)(di + 1) +
				   btrfs_dir_name_len(leaf, di));
	read_extent_buffer(leaf, buffer, data_ptr,
			   btrfs_dir_data_len(leaf, di));
	ret = btrfs_dir_data_len(leaf, di);

out:
	btrfs_free_path(path);
	return ret;
}

static int do_setxattr(struct btrfs_trans_handle *trans,
		       struct inode *inode, const char *name,
		       const void *value, size_t size, int flags)
{
	struct btrfs_dir_item *di;
	struct btrfs_root *root = BTRFS_I(inode)->root;
	struct btrfs_path *path;
	size_t name_len = strlen(name);
	int ret = 0;

	if (name_len + size > BTRFS_MAX_XATTR_SIZE(root))
		return -ENOSPC;

	path = btrfs_alloc_path();
	if (!path)
		return -ENOMEM;

	/* first lets see if we already have this xattr */
	di = btrfs_lookup_xattr(trans, root, path, btrfs_ino(inode), name,
				strlen(name), -1);
	if (IS_ERR(di)) {
		ret = PTR_ERR(di);
		goto out;
	}

	/* ok we already have this xattr, lets remove it */
	if (di) {
		/* if we want create only exit */
		if (flags & XATTR_CREATE) {
			ret = -EEXIST;
			goto out;
		}

		ret = btrfs_delete_one_dir_name(trans, root, path, di);
		BUG_ON(ret);
		btrfs_release_path(root, path);

		/* if we don't have a value then we are removing the xattr */
		if (!value)
			goto out;
	} else {
		btrfs_release_path(root, path);

		if (flags & XATTR_REPLACE) {
			/* we couldn't find the attr to replace */
			ret = -ENODATA;
			goto out;
		}
	}

	/* ok we have to create a completely new xattr */
	ret = btrfs_insert_xattr_item(trans, root, path, btrfs_ino(inode),
				      name, name_len, value, size);
	BUG_ON(ret);
out:
	btrfs_free_path(path);
	return ret;
}

int __btrfs_setxattr(struct btrfs_trans_handle *trans,
		     struct inode *inode, const char *name,
		     const void *value, size_t size, int flags)
{
	struct btrfs_root *root = BTRFS_I(inode)->root;
	int ret;

	if (trans)
		return do_setxattr(trans, inode, name, value, size, flags);

	trans = btrfs_start_transaction(root, 2);
	if (IS_ERR(trans))
		return PTR_ERR(trans);

	btrfs_set_trans_block_group(trans, inode);

	ret = do_setxattr(trans, inode, name, value, size, flags);
	if (ret)
		goto out;

	inode->i_ctime = CURRENT_TIME;
	ret = btrfs_update_inode(trans, root, inode);
	BUG_ON(ret);
out:
	btrfs_end_transaction_throttle(trans, root);
	return ret;
}

ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size)
{
	struct btrfs_key key, found_key;
	struct inode *inode = dentry->d_inode;
	struct btrfs_root *root = BTRFS_I(inode)->root;
	struct btrfs_path *path;
	struct extent_buffer *leaf;
	struct btrfs_dir_item *di;
	int ret = 0, slot;
	size_t total_size = 0, size_left = size;
	unsigned long name_ptr;
	size_t name_len;

	/*
	 * ok we want all objects associated with this id.
	 * NOTE: we set key.offset = 0; because we want to start with the
	 * first xattr that we find and walk forward
	 */
	key.objectid = btrfs_ino(inode);
	btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
	key.offset = 0;

	path = btrfs_alloc_path();
	if (!path)
		return -ENOMEM;
	path->reada = 2;

	/* search for our xattrs */
	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
	if (ret < 0)
		goto err;

	while (1) {
		leaf = path->nodes[0];
		slot = path->slots[0];

		/* this is where we start walking through the path */
		if (slot >= btrfs_header_nritems(leaf)) {
			/*
			 * if we've reached the last slot in this leaf we need
			 * to go to the next leaf and reset everything
			 */
			ret = btrfs_next_leaf(root, path);
			if (ret < 0)
				goto err;
			else if (ret > 0)
				break;
			continue;
		}

		btrfs_item_key_to_cpu(leaf, &found_key, slot);

		/* check to make sure this item is what we want */
		if (found_key.objectid != key.objectid)
			break;
		if (btrfs_key_type(&found_key) != BTRFS_XATTR_ITEM_KEY)
			break;

		di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
		if (verify_dir_item(root, leaf, di))
			continue;

		name_len = btrfs_dir_name_len(leaf, di);
		total_size += name_len + 1;

		/* we are just looking for how big our buffer needs to be */
		if (!size)
			goto next;

		if (!buffer || (name_len + 1) > size_left) {
			ret = -ERANGE;
			goto err;
		}

		name_ptr = (unsigned long)(di + 1);
		read_extent_buffer(leaf, buffer, name_ptr, name_len);
		buffer[name_len] = '\0';

		size_left -= name_len + 1;
		buffer += name_len + 1;
next:
		path->slots[0]++;
	}
	ret = total_size;

err:
	btrfs_free_path(path);

	return ret;
}

/*
 * List of handlers for synthetic system.* attributes.  All real ondisk
 * attributes are handled directly.
 */
const struct xattr_handler *btrfs_xattr_handlers[] = {
#ifdef CONFIG_BTRFS_FS_POSIX_ACL
	&btrfs_xattr_acl_access_handler,
	&btrfs_xattr_acl_default_handler,
#endif
	NULL,
};

/*
 * Check if the attribute is in a supported namespace.
 *
 * This applied after the check for the synthetic attributes in the system
 * namespace.
 */
static bool btrfs_is_valid_xattr(const char *name)
{
	return !strncmp(name, XATTR_SECURITY_PREFIX,
			XATTR_SECURITY_PREFIX_LEN) ||
	       !strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) ||
	       !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) ||
	       !strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN);
}

ssize_t btrfs_getxattr(struct dentry *dentry, const char *name,
		       void *buffer, size_t size)
{
	/*
	 * If this is a request for a synthetic attribute in the system.*
	 * namespace use the generic infrastructure to resolve a handler
	 * for it via sb->s_xattr.
	 */
	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
		return generic_getxattr(dentry, name, buffer, size);

	if (!btrfs_is_valid_xattr(name))
		return -EOPNOTSUPP;
	return __btrfs_getxattr(dentry->d_inode, name, buffer, size);
}

int btrfs_setxattr(struct dentry *dentry, const char *name, const void *value,
		   size_t size, int flags)
{
	struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root;

	/*
	 * The permission on security.* and system.* is not checked
	 * in permission().
	 */
	if (btrfs_root_readonly(root))
		return -EROFS;

	/*
	 * If this is a request for a synthetic attribute in the system.*
	 * namespace use the generic infrastructure to resolve a handler
	 * for it via sb->s_xattr.
	 */
	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
		return generic_setxattr(dentry, name, value, size, flags);

	if (!btrfs_is_valid_xattr(name))
		return -EOPNOTSUPP;

	if (size == 0)
		value = "";  /* empty EA, do not remove */

	return __btrfs_setxattr(NULL, dentry->d_inode, name, value, size,
				flags);
}

int btrfs_removexattr(struct dentry *dentry, const char *name)
{
	struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root;

	/*
	 * The permission on security.* and system.* is not checked
	 * in permission().
	 */
	if (btrfs_root_readonly(root))
		return -EROFS;

	/*
	 * If this is a request for a synthetic attribute in the system.*
	 * namespace use the generic infrastructure to resolve a handler
	 * for it via sb->s_xattr.
	 */
	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
		return generic_removexattr(dentry, name);

	if (!btrfs_is_valid_xattr(name))
		return -EOPNOTSUPP;

	return __btrfs_setxattr(NULL, dentry->d_inode, name, NULL, 0,
				XATTR_REPLACE);
}

int btrfs_xattr_security_init(struct btrfs_trans_handle *trans,
			      struct inode *inode, struct inode *dir)
{
	int err;
	size_t len;
	void *value;
	char *suffix;
	char *name;

	err = security_inode_init_security(inode, dir, &suffix, &value, &len);
	if (err) {
		if (err == -EOPNOTSUPP)
			return 0;
		return err;
	}

	name = kmalloc(XATTR_SECURITY_PREFIX_LEN + strlen(suffix) + 1,
		       GFP_NOFS);
	if (!name) {
		err = -ENOMEM;
	} else {
		strcpy(name, XATTR_SECURITY_PREFIX);
		strcpy(name + XATTR_SECURITY_PREFIX_LEN, suffix);
		err = __btrfs_setxattr(trans, inode, name, value, len, 0);
		kfree(name);
	}

	kfree(suffix);
	kfree(value);
	return err;
}
Commit	Line	Data
5103e947 JB	1	/*
	2	* Copyright (C) 2007 Red Hat. All rights reserved.
	3	*
	4	* This program is free software; you can redistribute it and/or
	5	* modify it under the terms of the GNU General Public
	6	* License v2 as published by the Free Software Foundation.
	7	*
	8	* This program is distributed in the hope that it will be useful,
	9	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	10	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	11	* General Public License for more details.
	12	*
	13	* You should have received a copy of the GNU General Public
	14	* License along with this program; if not, write to the
	15	* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
	16	* Boston, MA 021110-1307, USA.
	17	*/
	18
	19	#include <linux/init.h>
	20	#include <linux/fs.h>
	21	#include <linux/slab.h>
	22	#include <linux/rwsem.h>
	23	#include <linux/xattr.h>
0279b4cd	24	#include <linux/security.h>
5103e947 JB	25	#include "ctree.h"
	26	#include "btrfs_inode.h"
	27	#include "transaction.h"
	28	#include "xattr.h"
	29	#include "disk-io.h"
33268eaf	30
5103e947	31
95819c05 CH	32	ssize_t __btrfs_getxattr(struct inode inode, const char name,
95819c05 CH	33	void *buffer, size_t size)
5103e947 JB	34	{
	35	struct btrfs_dir_item *di;
	36	struct btrfs_root *root = BTRFS_I(inode)->root;
	37	struct btrfs_path *path;
	38	struct extent_buffer *leaf;
5103e947 JB	39	int ret = 0;
5103e947 JB	40	unsigned long data_ptr;
5103e947 JB	41
5103e947 JB	42	path = btrfs_alloc_path();
95819c05	43	if (!path)
5103e947	44	return -ENOMEM;
5103e947	45
5103e947	46	/* lookup the xattr by name */
33345d01	47	di = btrfs_lookup_xattr(NULL, root, path, btrfs_ino(inode), name,
5103e947	48	strlen(name), 0);
07060404	49	if (!di) {
5103e947 JB	50	ret = -ENODATA;
5103e947 JB	51	goto out;
07060404 JB	52	} else if (IS_ERR(di)) {
	53	ret = PTR_ERR(di);
	54	goto out;
5103e947 JB	55	}
	56
	57	leaf = path->nodes[0];
	58	/* if size is 0, that means we want the size of the attr */
	59	if (!size) {
	60	ret = btrfs_dir_data_len(leaf, di);
	61	goto out;
	62	}
	63
	64	/* now get the data out of our dir_item */
	65	if (btrfs_dir_data_len(leaf, di) > size) {
	66	ret = -ERANGE;
	67	goto out;
	68	}
07060404 JB	69
	70	/*
	71	* The way things are packed into the leaf is like this
	72	* \|struct btrfs_dir_item\|name\|data\|
	73	* where name is the xattr name, so security.foo, and data is the
	74	* content of the xattr. data_ptr points to the location in memory
	75	* where the data starts in the in memory leaf
	76	*/
5103e947 JB	77	data_ptr = (unsigned long)((char *)(di + 1) +
	78	btrfs_dir_name_len(leaf, di));
	79	read_extent_buffer(leaf, buffer, data_ptr,
3acd7ee8	80	btrfs_dir_data_len(leaf, di));
5103e947 JB	81	ret = btrfs_dir_data_len(leaf, di);
	82
	83	out:
5103e947 JB	84	btrfs_free_path(path);
	85	return ret;
	86	}
	87
f34f57a3 YZ	88	static int do_setxattr(struct btrfs_trans_handle *trans,
	89	struct inode inode, const char name,
	90	const void *value, size_t size, int flags)
5103e947 JB	91	{
	92	struct btrfs_dir_item *di;
	93	struct btrfs_root *root = BTRFS_I(inode)->root;
5103e947	94	struct btrfs_path *path;
f34f57a3 YZ	95	size_t name_len = strlen(name);
	96	int ret = 0;
	97
	98	if (name_len + size > BTRFS_MAX_XATTR_SIZE(root))
	99	return -ENOSPC;
5103e947 JB	100
5103e947 JB	101	path = btrfs_alloc_path();
95819c05	102	if (!path)
5103e947	103	return -ENOMEM;
5103e947	104
5103e947	105	/* first lets see if we already have this xattr */
33345d01	106	di = btrfs_lookup_xattr(trans, root, path, btrfs_ino(inode), name,
5103e947 JB	107	strlen(name), -1);
	108	if (IS_ERR(di)) {
	109	ret = PTR_ERR(di);
	110	goto out;
	111	}
	112
	113	/* ok we already have this xattr, lets remove it */
	114	if (di) {
	115	/* if we want create only exit */
	116	if (flags & XATTR_CREATE) {
	117	ret = -EEXIST;
	118	goto out;
	119	}
	120
	121	ret = btrfs_delete_one_dir_name(trans, root, path, di);
f34f57a3	122	BUG_ON(ret);
5103e947 JB	123	btrfs_release_path(root, path);
	124
	125	/* if we don't have a value then we are removing the xattr */
f34f57a3	126	if (!value)
5103e947	127	goto out;
33268eaf JB	128	} else {
	129	btrfs_release_path(root, path);
	130
	131	if (flags & XATTR_REPLACE) {
	132	/* we couldn't find the attr to replace */
	133	ret = -ENODATA;
	134	goto out;
	135	}
5103e947 JB	136	}
	137
	138	/* ok we have to create a completely new xattr */
33345d01	139	ret = btrfs_insert_xattr_item(trans, root, path, btrfs_ino(inode),
f34f57a3 YZ	140	name, name_len, value, size);
	141	BUG_ON(ret);
	142	out:
	143	btrfs_free_path(path);
	144	return ret;
	145	}
	146
	147	int __btrfs_setxattr(struct btrfs_trans_handle *trans,
	148	struct inode inode, const char name,
	149	const void *value, size_t size, int flags)
	150	{
	151	struct btrfs_root *root = BTRFS_I(inode)->root;
	152	int ret;
	153
	154	if (trans)
	155	return do_setxattr(trans, inode, name, value, size, flags);
	156
a22285a6 YZ	157	trans = btrfs_start_transaction(root, 2);
	158	if (IS_ERR(trans))
	159	return PTR_ERR(trans);
5103e947	160
f34f57a3	161	btrfs_set_trans_block_group(trans, inode);
5103e947	162
f34f57a3 YZ	163	ret = do_setxattr(trans, inode, name, value, size, flags);
	164	if (ret)
	165	goto out;
	166
	167	inode->i_ctime = CURRENT_TIME;
	168	ret = btrfs_update_inode(trans, root, inode);
	169	BUG_ON(ret);
	170	out:
	171	btrfs_end_transaction_throttle(trans, root);
5103e947 JB	172	return ret;
	173	}
	174
	175	ssize_t btrfs_listxattr(struct dentry dentry, char buffer, size_t size)
	176	{
	177	struct btrfs_key key, found_key;
	178	struct inode *inode = dentry->d_inode;
	179	struct btrfs_root *root = BTRFS_I(inode)->root;
	180	struct btrfs_path *path;
5103e947 JB	181	struct extent_buffer *leaf;
5103e947 JB	182	struct btrfs_dir_item *di;
2e6a0035	183	int ret = 0, slot;
eaa47d86	184	size_t total_size = 0, size_left = size;
5103e947	185	unsigned long name_ptr;
eaa47d86	186	size_t name_len;
5103e947 JB	187
	188	/*
	189	* ok we want all objects associated with this id.
	190	* NOTE: we set key.offset = 0; because we want to start with the
	191	* first xattr that we find and walk forward
	192	*/
33345d01	193	key.objectid = btrfs_ino(inode);
5103e947 JB	194	btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
	195	key.offset = 0;
	196
	197	path = btrfs_alloc_path();
5103e947 JB	198	if (!path)
5103e947 JB	199	return -ENOMEM;
1caf9342	200	path->reada = 2;
5103e947	201
5103e947 JB	202	/* search for our xattrs */
	203	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
	204	if (ret < 0)
	205	goto err;
2e6a0035	206
5103e947 JB	207	while (1) {
5103e947 JB	208	leaf = path->nodes[0];
5103e947 JB	209	slot = path->slots[0];
	210
	211	/* this is where we start walking through the path */
2e6a0035	212	if (slot >= btrfs_header_nritems(leaf)) {
5103e947 JB	213	/*
	214	* if we've reached the last slot in this leaf we need
	215	* to go to the next leaf and reset everything
	216	*/
2e6a0035 LZ	217	ret = btrfs_next_leaf(root, path);
	218	if (ret < 0)
	219	goto err;
	220	else if (ret > 0)
	221	break;
	222	continue;
5103e947	223	}
5103e947	224
5103e947 JB	225	btrfs_item_key_to_cpu(leaf, &found_key, slot);
	226
	227	/* check to make sure this item is what we want */
	228	if (found_key.objectid != key.objectid)
	229	break;
	230	if (btrfs_key_type(&found_key) != BTRFS_XATTR_ITEM_KEY)
	231	break;
	232
	233	di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
22a94d44 JB	234	if (verify_dir_item(root, leaf, di))
22a94d44 JB	235	continue;
5103e947	236
eaa47d86 CH	237	name_len = btrfs_dir_name_len(leaf, di);
eaa47d86 CH	238	total_size += name_len + 1;
5103e947 JB	239
	240	/* we are just looking for how big our buffer needs to be */
	241	if (!size)
2e6a0035	242	goto next;
5103e947	243
eaa47d86	244	if (!buffer \|\| (name_len + 1) > size_left) {
5103e947	245	ret = -ERANGE;
b16281c3	246	goto err;
5103e947 JB	247	}
5103e947 JB	248
eaa47d86 CH	249	name_ptr = (unsigned long)(di + 1);
	250	read_extent_buffer(leaf, buffer, name_ptr, name_len);
	251	buffer[name_len] = '\0';
	252
	253	size_left -= name_len + 1;
	254	buffer += name_len + 1;
2e6a0035 LZ	255	next:
2e6a0035 LZ	256	path->slots[0]++;
5103e947 JB	257	}
	258	ret = total_size;
	259
	260	err:
5103e947 JB	261	btrfs_free_path(path);
	262
	263	return ret;
	264	}
	265
5103e947	266	/*
95819c05 CH	267	* List of handlers for synthetic system.* attributes. All real ondisk
	268	* attributes are handled directly.
	269	*/
f01cbd3f	270	const struct xattr_handler *btrfs_xattr_handlers[] = {
0eda294d	271	#ifdef CONFIG_BTRFS_FS_POSIX_ACL
95819c05 CH	272	&btrfs_xattr_acl_access_handler,
	273	&btrfs_xattr_acl_default_handler,
	274	#endif
	275	NULL,
	276	};
	277
	278	/*
	279	* Check if the attribute is in a supported namespace.
	280	*
	281	* This applied after the check for the synthetic attributes in the system
	282	* namespace.
5103e947	283	*/
95819c05 CH	284	static bool btrfs_is_valid_xattr(const char *name)
95819c05 CH	285	{
d397712b CM	286	return !strncmp(name, XATTR_SECURITY_PREFIX,
d397712b CM	287	XATTR_SECURITY_PREFIX_LEN) \|\|
95819c05 CH	288	!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) \|\|
	289	!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) \|\|
	290	!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN);
69a32ac5 CM	291	}
69a32ac5 CM	292
95819c05 CH	293	ssize_t btrfs_getxattr(struct dentry dentry, const char name,
	294	void *buffer, size_t size)
	295	{
	296	/*
	297	* If this is a request for a synthetic attribute in the system.*
	298	* namespace use the generic infrastructure to resolve a handler
	299	* for it via sb->s_xattr.
	300	*/
	301	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
	302	return generic_getxattr(dentry, name, buffer, size);
5103e947	303
95819c05 CH	304	if (!btrfs_is_valid_xattr(name))
	305	return -EOPNOTSUPP;
	306	return __btrfs_getxattr(dentry->d_inode, name, buffer, size);
	307	}
5103e947	308
95819c05 CH	309	int btrfs_setxattr(struct dentry dentry, const char name, const void *value,
	310	size_t size, int flags)
	311	{
b83cc969 LZ	312	struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root;
	313
	314	/*
	315	* The permission on security.* and system.* is not checked
	316	* in permission().
	317	*/
	318	if (btrfs_root_readonly(root))
	319	return -EROFS;
	320
95819c05 CH	321	/*
	322	* If this is a request for a synthetic attribute in the system.*
	323	* namespace use the generic infrastructure to resolve a handler
	324	* for it via sb->s_xattr.
	325	*/
	326	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
	327	return generic_setxattr(dentry, name, value, size, flags);
5103e947	328
95819c05 CH	329	if (!btrfs_is_valid_xattr(name))
95819c05 CH	330	return -EOPNOTSUPP;
5103e947	331
95819c05 CH	332	if (size == 0)
95819c05 CH	333	value = ""; /* empty EA, do not remove */
f34f57a3 YZ	334
	335	return __btrfs_setxattr(NULL, dentry->d_inode, name, value, size,
	336	flags);
95819c05 CH	337	}
	338
	339	int btrfs_removexattr(struct dentry dentry, const char name)
	340	{
b83cc969 LZ	341	struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root;
	342
	343	/*
	344	* The permission on security.* and system.* is not checked
	345	* in permission().
	346	*/
	347	if (btrfs_root_readonly(root))
	348	return -EROFS;
	349
95819c05 CH	350	/*
	351	* If this is a request for a synthetic attribute in the system.*
	352	* namespace use the generic infrastructure to resolve a handler
	353	* for it via sb->s_xattr.
	354	*/
	355	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
	356	return generic_removexattr(dentry, name);
	357
	358	if (!btrfs_is_valid_xattr(name))
	359	return -EOPNOTSUPP;
f34f57a3 YZ	360
	361	return __btrfs_setxattr(NULL, dentry->d_inode, name, NULL, 0,
	362	XATTR_REPLACE);
95819c05	363	}
0279b4cd	364
f34f57a3 YZ	365	int btrfs_xattr_security_init(struct btrfs_trans_handle *trans,
f34f57a3 YZ	366	struct inode inode, struct inode dir)
0279b4cd JO	367	{
	368	int err;
	369	size_t len;
	370	void *value;
	371	char *suffix;
	372	char *name;
	373
	374	err = security_inode_init_security(inode, dir, &suffix, &value, &len);
	375	if (err) {
	376	if (err == -EOPNOTSUPP)
	377	return 0;
	378	return err;
	379	}
	380
	381	name = kmalloc(XATTR_SECURITY_PREFIX_LEN + strlen(suffix) + 1,
	382	GFP_NOFS);
	383	if (!name) {
	384	err = -ENOMEM;
	385	} else {
	386	strcpy(name, XATTR_SECURITY_PREFIX);
	387	strcpy(name + XATTR_SECURITY_PREFIX_LEN, suffix);
f34f57a3	388	err = __btrfs_setxattr(trans, inode, name, value, len, 0);
0279b4cd JO	389	kfree(name);
	390	}
	391
	392	kfree(suffix);
	393	kfree(value);
	394	return err;
	395	}